Bridge Inductance of Induction Motor with Closed Rotor Slots
NASA Astrophysics Data System (ADS)
Matsushita, Makoto; Ishibashi, Fuminori; Suzuki, Takao; Noda, Shinichi
Closed rotor slots are widely employed in low-power squirrel-cage induction motors with die-cast aluminum cage rotors. Die-cast aluminum cages with closed rotor slots can be manufactured commercially. They help reduce flux pulsation in air gaps, attenuate acoustic noises, and achieve high efficiency. However, it is difficult to calculate bridge inductance of a closed rotor slot accurately because the main flux passes through the bridge and iron saturation can be achieved depending upon the bar current. In this study, bridge inductance was investigated by using a search coil and by FEM analysis and conventional equations. The bridge flux density and the bridge linkage flux were measured by using 4P-0.75kW motor with closed rotor slots, and the bridge inductance was calculated as a function of rotor bar current. The bridge inductance was also analyzed by FEM, and the results were analytically checked by using the calculated conventional equations. From these analyses, it is seen that the measured values of the bridge inductance are in good agreement with the values calculated by FEM and conventional methods. It is verified that the bridge inductance shows a trend similar to that of the μ-H curve of the rotor steel sheet.
Equivalence Between Squirrel Cage and Sheet Rotor Induction Motor
NASA Astrophysics Data System (ADS)
Dwivedi, Ankita; Singh, S. K.; Srivastava, R. K.
2015-03-01
Due to topological changes in dual stator induction motor and high cost of its fabrication, it is convenient to replace the squirrel cage rotor with a composite sheet rotor. For an experimental machine, the inner and outer stator stampings are normally available whereas the procurement of rotor stampings is quite cumbersome and is not always cost effective. In this paper, the equivalence between sheet/solid rotor induction motor and squirrel cage induction motor has been investigated using layer theory of electrical machines, so as to enable one to utilize sheet/solid rotor in dual port experimental machines.
Equivalence Between Squirrel Cage and Sheet Rotor Induction Motor
NASA Astrophysics Data System (ADS)
Dwivedi, Ankita; Singh, S. K.; Srivastava, R. K.
2016-06-01
Due to topological changes in dual stator induction motor and high cost of its fabrication, it is convenient to replace the squirrel cage rotor with a composite sheet rotor. For an experimental machine, the inner and outer stator stampings are normally available whereas the procurement of rotor stampings is quite cumbersome and is not always cost effective. In this paper, the equivalence between sheet/solid rotor induction motor and squirrel cage induction motor has been investigated using layer theory of electrical machines, so as to enable one to utilize sheet/solid rotor in dual port experimental machines.
Vibration of Induction Motor Rotor in Rotating Magnetic Field
NASA Astrophysics Data System (ADS)
Iwata, Yoshio; Sato, Hidenori; Komatsuzaki, Toshihiko; Saito, Takuhiro
The rotor vibration of two-pole induction motor with rotating magnetic field has been investigated. The vibration is measured at any relative location of the stator and the rotor with various power supply frequencies in the experiment and is analyzed in consideration of mechanical factors of the rotor. The following conclusion is obtained through the experiment and the analysis; (1) 2ω vibration of twice the power supply frequency ω is generated because of offset between the stator center and the gyrational center of the rotor. (2) Two vibrations of ω(1-s) and ω(1+s) where s is slip ratio are generated because of the rotor unbalance or the disagreement between the gyrational center and geometrical center of the rotor. (3) An unstable vibration is predicted in the analysis when the power supply frequency is equal to natural frequency of the rotor, however, the unstable vibration was not generated in the experiment because of the damping.
Fuzzy Logic Based Rotor Health Index of Induction Motor
NASA Astrophysics Data System (ADS)
Misra, Rajul; Pahuja, G. L.
2015-10-01
This paper presents an experimental study on detection and diagnosis of broken rotor bars in Squirrel Cage Induction Motor (SQIM). The proposed scheme is based on Motor Current Signature Analysis (MCSA) which uses amplitude difference of supply frequency to upper and lower side bands. Initially traditional MCSA has been used for rotor fault detection. It provides rotor health index on full load conditions. However in real practice if a fault occurs motor can not run at full load. To overcome the issue of reduced load condition a Fuzzy Logic based MCSA has been designed, implemented, tested and compared with traditional MCSA. A simulation result shows that proposed scheme is not only capable of detecting the severity of rotor fault but also provides remarkable performance at reduced load conditions.
Offline detection of broken rotor bars in AC induction motors
NASA Astrophysics Data System (ADS)
Powers, Craig Stephen
ABSTRACT. OFFLINE DETECTION OF BROKEN ROTOR BARS IN AC INDUCTION MOTORS. The detection of the broken rotor bar defect in medium- and large-sized AC induction machines is currently one of the most difficult tasks for the motor condition and monitoring industry. If a broken rotor bar defect goes undetected, it can cause a catastrophic failure of an expensive machine. If a broken rotor bar defect is falsely determined, it wastes time and money to physically tear down and inspect the machine only to find an incorrect diagnosis. Previous work in 2009 at Baker/SKF-USA in collaboration with the Korea University has developed a prototype instrument that has been highly successful in correctly detecting the broken rotor bar defect in ACIMs where other methods have failed. Dr. Sang Bin and his students at the Korea University have been using this prototype instrument to help the industry save money in the successful detection of the BRB defect. A review of the current state of motor conditioning and monitoring technology for detecting the broken rotor bar defect in ACIMs shows improved detection of this fault is still relevant. An analysis of previous work in the creation of this prototype instrument leads into the refactoring of the software and hardware into something more deployable, cost effective and commercially viable.
Rotor resistance estimator design for indirect field-oriented induction motors
NASA Astrophysics Data System (ADS)
Zhao, Jianhui; Wu, Zhong
2006-11-01
Exact information of the rotor resistance is the key to realize high-performance indirect field-oriented control of the induction motors. However, rotor resistance is time-varying when the motor works. Therefore, a new estimator of the rotor resistance is designed for the indirect field-oriented induction motors to attenuate the effect of the rotor resistance uncertainty. This estimator is derived from the steady-state procedure of the rotor flux using Lyapunov stability theory. Furthermore, this estimator is shown to be able to minimize the steady-state error the rotor flux and improve the control performance of the induction motor drive effectively. Compared with the previous studies, this estimator has a simple form and is easy to implement. Simulation results of a certain IFOC induction motor indicate that the estimator presented above is feasible.
Sensorless Detection of Induction Motor Rotor Faults Using the Clarke Vector Approach
NASA Astrophysics Data System (ADS)
Vaimann, Toomas; Kallaste, Ants; Kilk, Aleksander
2011-01-01
Due to their rugged build, simplicity and cost effective performance, induction motors are used in a vast number of industries, where they play a significant role in responsible operations, where faults and downtimes are either not desirable or even unthinkable. As different faults can affect the performance of the induction motors, among them broken rotor bars, it is important to have a certain condition monitoring or diagnostic system that is guarding the state of the motor. This paper deals with induction motor broken rotor bars detection, using Clarke vector approach.
Matsuse, Kouki; Katsuta, Seiji; Tsukakoshi, Masahiko; Ohta, Masaru; Huang, L.
1995-12-31
A method of using an adaptive rotor flux observer to rapidly control the rotor flux of direct-field-oriented induction motors driven by a deadbeat rotor flux controller has been developed. The method ensures maximum efficiency in the steady state without degradation of the dynamic response. Furthermore, to solve the problem of flux current variations that arise from small errors in the measurement of the stator voltage and current, a flux current reference is calculated from the appropriate rotor flux in the steady state. Simulation and experimental results for an induction motor have demonstrated that this method yields the maximum efficiency and good speed response to changes in both torque and motor speed without any degradation in the transient characteristics.
Novel indices for broken rotor bars fault diagnosis in induction motors using wavelet transform
NASA Astrophysics Data System (ADS)
Ebrahimi, Bashir Mahdi; Faiz, Jawad; Lotfi-fard, S.; Pillay, P.
2012-07-01
This paper introduces novel indices for broken rotor bars diagnosis in three-phase induction motors based on wavelet coefficients of stator current in a specific frequency band. These indices enable to diagnose occurrence and determine number of broken bars in different loads precisely. Besides thanks to the suitability of wavelet transform in transient conditions, it is possible to detect the fault during the start-up of the motor. This is important in the case of start-up of large induction motors with long starting time and also motors with frequent start-up. Furthermore, broken rotor bars in induction motor are detected using spectra analysis of the stator current. It is also shown that rise of number of broken bars and load levels increases amplitude of the particular side-band components of the stator currents in the faulty case. An induction motor with 1, 2, 3 and 4 broken bars at the rated load and the motor with 4 broken bars at no-load, 33%, 66%, 100% and 133% rated load are investigated. Time stepping finite element method is used for modeling broken rotor bars faults in induction motors. In this modeling, effects of the stator winding distribution, stator and rotor slots, geometrical and physical characteristics of different parts of the motor and non-linearity of the core materials are taken into account. The simulation results are are verified by the experimental results.
A Comparison of Different Techniques for Induction Motor Rotor Fault Diagnosis
NASA Astrophysics Data System (ADS)
Alwodai, A.; Gu, F.; Ball, A. D.
2012-05-01
The problem of failures in induction motors is a large concern due to its significant influence over industrial production. Therefore a large number of detection techniques were presented to avoid this problem. This paper presents the comparison results of induction motor rotor fault detection using three methods: motor current signature analysis (MCSA), surface vibration (SV), and instantaneous angular speed (IAS). These three measurements were performed under different loads with three rotor conditions: baseline, one rotor bar broken and two rotor bar broken. The faults can be detected and diagnosed based on the amplitude difference of the characteristic frequency components of power spectrum. However IAS may be the best technique because it gives the clearest spectrum representation in which the largest amplitude change is observed due to the faults.
Loss Calculation of Induction Motors Considering Harmonic Electromagnetic Fields in Stator and Rotor
NASA Astrophysics Data System (ADS)
Yamazaki, Katsumi
A method of loss calculation for induction motors is proposed. The combined 3D-2D time stepping finite element analysis is carried out to obtain the copper loss and the time-variation of the magnetic field in the motor. The iron loss is calculated approximately considering the time-variation of the magnetic field direction and the minor hysteresis loops caused by the time-harmonic fields using practical computer resources. The proposed method is applied to 4 types of induction motors, which are the solid rotor induction motors with/without slot and the cage induction motors with/without skew. The measured and the calculated total losses and the iron losses agree well in all cases. The differences of the loss distributions of each motor are also compared and investigated.
Diagnostics of an induction-motor rotor by the spectral analysis of stator currents
NASA Astrophysics Data System (ADS)
Weinreb, K.
2013-12-01
A method for achieving more efficient revealing and more unambiguous evaluation of various kinds of defects in the induction-motor (IM) rotor, which is based on changes occurring in the characteristic signs of the spectrum of the stator current, is presented. The results and analysis of measurements performed for artificially specified cases of faults in the rotor of a small-capacity IM are presented.
Disk-shaped superconducting rotor for an axial flux induction motor
NASA Astrophysics Data System (ADS)
Álvarez, A.; Suárez, P.; Cáceres, D.; Granados, X.; Pérez, B.; Ceballos, J. M.
2003-11-01
Most work on bulk-based superconducting electrical motors has been done with superconducting materials in the rotor only, due to the difficulty in machining the material into the conventional coil shape. As part of the design of a superconducting induction motor with superconductors in both rotor and stator, we made a disk-shaped rotor from the same YBCO bulks that we use to fabricate ceramic coils in constructing a modular stator for a biphasic axial flux motor, and studied this rotor’s working behaviour. To this end we constructed a system to simulate the working environment of a YBCO disk within the motor, and measured the magnetic field in the disk and the speed-torque characteristic.
NASA Astrophysics Data System (ADS)
Kiyotake, Hirofumi; Shinohara, Katsuji; Yamamoto, Kichiro
Speed sensorless vector controlled induction motor drives are the standard choice in many industrial applications, but this can hardly control torque and rotor speed at low speed. Recently, a method based on the high-frequency signal injection has been studied. This paper presents a method for suppressing the effects of the saturation saliency by using high pass filter, and a new approach to estimate the rotor speed. The effectiveness of these methods are demonstrated through experimental results showing both good suppression of saturation harmonics and good sensorless speed control at low speed.
A new diagnosis of broken rotor bar fault extent in three phase squirrel cage induction motor
NASA Astrophysics Data System (ADS)
Shi, Pu; Chen, Zheng; Vagapov, Yuriy; Zouaoui, Zoubir
2014-01-01
This paper proposes a new induction motor broken bar fault extent diagnostic approach under varying load conditions based on wavelet coefficients of stator current in a specific frequency band. In this paper, winding function approach (WFA) is used to develop a mathematical model to provide indication references for parameters under different load levels and different fault cases. It is shown that rise of number of broken bars and load levels increases amplitude of the particular side band components of the stator currents in faulty case. Stator current, rotor speed and torque are used to demonstrate the relationship between these parameters and broken rotor bar severity. An induction motor with 1, 2 and 3 broken bars and the motor with 3 broken bars in experiment at no-load, 50% and 100% load are investigated. A novel criterion is then developed to assess rotor fault severity based on the stator current and the rotor speed. Simulations and experimental results confirm the validity of the proposed approach.
NASA Astrophysics Data System (ADS)
Park, Chang-Woo; Hwang, Jung-Hoon
2013-03-01
This paper presents an observer design for the estimation of magnetic rotor flux of induction motors. We characterize the class of MIMO induction motor systems that consists of the linear observable and the nonlinear part with a block triangular structure. The similarity transformation that plays an important role in proving the convergence of the proposed observer is generalized to the systems. Since the gain of the proposed observer minimizes a nonlinear part of the system to suppress for the stability of the error dynamics, it improves the transient performance of the high gain observer. Moreover, by using the generalized similarity transformation, it is shown that under some observability and boundedness conditions, the proposed observer guarantees the global exponential convergence to zero of the estimation error. Since the proposed scheme minimizes the nonlinearity of an induction motor system, it improves the transient performance of the observer and guarantees the global exponential convergence to zero of the estimation error. The estimation results of magnetic rotor fluxes through experiments are shown and it is presented that the proposed magnetic flux observer exhibits less transient oscillation and faster convergence time than the general observer.
Emotional Learning Based Intelligent Controllers for Rotor Flux Oriented Control of Induction Motor
NASA Astrophysics Data System (ADS)
Abdollahi, Rohollah; Farhangi, Reza; Yarahmadi, Ali
2014-08-01
This paper presents design and evaluation of a novel approach based on emotional learning to improve the speed control system of rotor flux oriented control of induction motor. The controller includes a neuro-fuzzy system with speed error and its derivative as inputs. A fuzzy critic evaluates the present situation, and provides the emotional signal (stress). The controller modifies its characteristics so that the critics stress is reduced. The comparative simulation results show that the proposed controller is more robust and hence found to be a suitable replacement of the conventional PI controller for the high performance industrial drive applications.
The Design and its Verification of the Double Rotor Double Cage Induction Motor
NASA Astrophysics Data System (ADS)
Sinha, Sumita; Deb, Nirmal K.; Biswas, Sujit K.
2016-06-01
The concept of a double rotor motor presented earlier and its equivalent circuit has been developed, showing a non-linear parameter content. The two rotors (which are recommended to be double cage type for development of high starting torque) can run with equal or unequal speed independently, depending on their individual loading. This paper presents the elaborate design procedure, step-by-step, for the double rotor double cage motor and verifies the designed data with that obtained from three separate tests (compared to two for conventional motor) on a prototype, such that optimum performance can be obtained from the motor.
NASA Astrophysics Data System (ADS)
Redinz, José Arnaldo
2015-09-01
We obtain analytical expressions for the torques and angular speed of an induction motor with a simple geometry, resembling the geometry of the first induction motor investigated by Arago in 1824. The rotor is a conducting disc rotating between the magnetic poles of two off-axis solenoids, displaced in space by 90^\\circ from each other. We apply our results to discuss a theory for the ubiquitous electromechanical watt-hour meter. For comparison of the theoretical result for the angular speed with measurements, we propose a simple experiment in which an induction motor with an aluminum disc rotor is constructed.
Talhaoui, Hicham; Menacer, Arezki; Kessal, Abdelhalim; Kechida, Ridha
2014-09-01
This paper presents new techniques to evaluate faults in case of broken rotor bars of induction motors. Procedures are applied with closed-loop control. Electrical and mechanical variables are treated using fast Fourier transform (FFT), and discrete wavelet transform (DWT) at start-up and steady state. The wavelet transform has proven to be an excellent mathematical tool for the detection of the faults particularly broken rotor bars type. As a performance, DWT can provide a local representation of the non-stationary current signals for the healthy machine and with fault. For sensorless control, a Luenberger observer is applied; the estimation rotor speed is analyzed; the effect of the faults in the speed pulsation is compensated; a quadratic current appears and used for fault detection. PMID:25004798
Elkasabgy, N.M.; Di Pietro, C.
1994-05-15
In this paper the authors describe a novel technique to model induction motors with a diecast stator and rotor and to examine the effects of various magnetic materials on the electrical performance of the motor. For electric vehicle applications, a high volume production operation of the electric motor requires the motor to be small and inexpensive. The expensive labor and material used to manufacture the motor encouraged the researchers to find new methods and techniques to reduce the cost and improve the performance. Diecast rotor and stator windings reduce motor cost and size. For diecasting induction motors, the motor laminations should be designed to optimize the electromagnetic field distribution over the cross section and along the axial direction. The magnetic material used for the laminations should also reduce losses and improve the overall efficiency. A 100 hp four-pole induction motor was modeled with finite elements, and the field distribution, the magnetic flux density, and the mechanical performance of the motor were computed using nonlinear magnetostatic and complex steady-state eddy current techniques. The difference in the electrical and mechanical performance of the motor were evaluated for copper and aluminum diecasting. The results show that copper diecasting of the rotor and the stator of the induction motor with magnetic material properties and identified slotting shape is the way to achieve better motor performance and low cost operation. 5 refs.
Gutierrez-Villalobos, Jose M; Rodriguez-Resendiz, Juvenal; Rivas-Araiza, Edgar A; Martínez-Hernández, Moisés A
2015-01-01
Three-phase induction motor drive requires high accuracy in high performance processes in industrial applications. Field oriented control, which is one of the most employed control schemes for induction motors, bases its function on the electrical parameter estimation coming from the motor. These parameters make an electrical machine driver work improperly, since these electrical parameter values change at low speeds, temperature changes, and especially with load and duty changes. The focus of this paper is the real-time and on-line electrical parameters with a CMAC-ADALINE block added in the standard FOC scheme to improve the IM driver performance and endure the driver and the induction motor lifetime. Two kinds of neural network structures are used; one to estimate rotor speed and the other one to estimate rotor resistance of an induction motor. PMID:26131677
Gutierrez-Villalobos, Jose M.; Rodriguez-Resendiz, Juvenal; Rivas-Araiza, Edgar A.; Martínez-Hernández, Moisés A.
2015-01-01
Three-phase induction motor drive requires high accuracy in high performance processes in industrial applications. Field oriented control, which is one of the most employed control schemes for induction motors, bases its function on the electrical parameter estimation coming from the motor. These parameters make an electrical machine driver work improperly, since these electrical parameter values change at low speeds, temperature changes, and especially with load and duty changes. The focus of this paper is the real-time and on-line electrical parameters with a CMAC-ADALINE block added in the standard FOC scheme to improve the IM driver performance and endure the driver and the induction motor lifetime. Two kinds of neural network structures are used; one to estimate rotor speed and the other one to estimate rotor resistance of an induction motor. PMID:26131677
NASA Astrophysics Data System (ADS)
Marčič, T.; Štumberger, B.; Štumberger, G.; Hadžiselimović, M.; Zagradišnik, I.
The electromechanical characteristics of induction motors depend on the used stator and rotor slot combination. The correlation between the usage of different stator and rotor slot number combinations, magnetic flux density distributions, no-load iron losses and rated load winding over-temperatures for a specific induction motor is presented. The motor's magnetic field was analyzed by traces of the magnetic flux density vector, obtained by FEM. Post-processing of FE magnetic field solution was used for posterior iron loss calculation of the motor iron loss at no-load. The examined motor stator lamination had 36 semi-closed slots and the rotor laminations had 28, 33, 34, 44 and 46 semi-closed slots.
NASA Astrophysics Data System (ADS)
Ghorbanian, Vahid; Faiz, Jawad
2015-03-01
This paper deals with the comprehensive detailed concepts of the rotor broken bars fault in industrial induction motors. It reviews the most important and applicable techniques for fault detection, and addresses fault diagnosing procedures at different supply modes including line-start and inverter-fed modes. Moreover, new analytical and experimental aspects of fault are proposed using the time and frequency domain variations of the motor variables such as current, voltage, electromagnetic torque and speed. Since the faulty motor behavior cannot be correctly identified without considering the motor operating condition, and the capability of the previous fault indicators are studied deeply in order to investigate their applicability at different conditions. These conditions include various faults, load and reference speed levels and also fault location. All in all, a precise condition assessment of the rotor broken bar induction motors, suitable for industrial purposes, is presented considering motor supply and conditions changes.
Rotor position sensor switches currents in brushless dc motors
NASA Technical Reports Server (NTRS)
1965-01-01
Reluctance switch incorporated in an induction motor is used for sensing rotor position and switching armature circuits in a brushless dc motor. This device drives the solar array system of an unmanned space satellite.
Homopolar motor with dual rotors
Hsu, John S.
1998-01-01
A homopolar motor (10) has a field rotor (15) mounted on a frame (11) for rotation in a first rotational direction and for producing an electromagnetic field, and an armature rotor (17) mounted for rotation on said frame (11) within said electromagnetic field and in a second rotational direction counter to said first rotational direction of said field rotor (15). The two rotors (15, 17) are coupled through a 1:1 gearing mechanism (19), so as to travel at the same speed but in opposite directions. This doubles the output voltage and output power, as compared to a motor in which only the armature is rotated. Several embodiments are disclosed.
Homopolar motor with dual rotors
Hsu, J.S.
1998-12-01
A homopolar motor has a field rotor mounted on a frame for rotation in a first rotational direction and for producing an electromagnetic field, and an armature rotor mounted for rotation on said frame within said electromagnetic field and in a second rotational direction counter to said first rotational direction of said field rotor. The two rotors are coupled through a 1:1 gearing mechanism, so as to travel at the same speed but in opposite directions. This doubles the output voltage and output power, as compared to a motor in which only the armature is rotated. Several embodiments are disclosed. 7 figs.
NASA Astrophysics Data System (ADS)
Kondo, Minoru; Kawamura, Junya; Terauchi, Nobuo
Performance tests are carried out to demonstrate the superiority of a permanent magnet synchronous motor to an induction motor as a traction motor for high-speed train. A prototype motor was manufactured by replacing the rotor of a conventional induction motor. The test results show that the permanent magnet motor is lighter, efficient and more silent than the induction motor because of the different rotor structure.
Hwang, Don-Ha; Woo, Byung-Chul; Sun, Jong-Ho; Kang, Dong-Sik; Han, Sang-Bo; Kim, Byung-Kuk; Cho, Youn-Hyun
2008-04-01
A new method for detecting eccentricity and broken rotor bar conditions in a squirrel-cage induction motor is proposed. Air-gap flux variation analysis is done using search coils, which are inserted at stator slots. Using this method, the leakage flux in radial direction can be directly detected. Using finite element method, the air-gap flux variation is accurately modeled and analyzed. From the results of the simulation, a motor under normal condition shows maximum magnetic flux density of 1.3 T. On the other hand, the eccentric air-gap condition displays about 1.1 T at 60 deg. and 1.6 T at 240 deg. A difference of flux density is 0.5 T in the abnormal condition, whereas no difference is detected in the normal motor. In the broken rotor bar conditions, the flux densities at 65 deg. and 155 deg. are about 0.4 T and 0.8 T, respectively. These simulation results are coincided with those of experiment. Consequently, the measurement of the magnetic flux at air gap is one of effective ways to discriminate the faulted conditions of the eccentricity and broken rotor bars.
NASA Astrophysics Data System (ADS)
Hwang, Don-Ha; Han, Sang-Bo; Woo, Byung-Chul; Sun, Jong-Ho; Kang, Dong-Sik; Kim, Byung-Kuk; Cho, Youn-Hyun
2008-04-01
A new method for detecting eccentricity and broken rotor bar conditions in a squirrel-cage induction motor is proposed. Air-gap flux variation analysis is done using search coils, which are inserted at stator slots. Using this method, the leakage flux in radial direction can be directly detected. Using finite element method, the air-gap flux variation is accurately modeled and analyzed. From the results of the simulation, a motor under normal condition shows maximum magnetic flux density of 1.3T. On the other hand, the eccentric air-gap condition displays about 1.1T at 60° and 1.6T at 240°. A difference of flux density is 0.5T in the abnormal condition, whereas no difference is detected in the normal motor. In the broken rotor bar conditions, the flux densities at 65° and 155° are about 0.4 T and 0.8T, respectively. These simulation results are coincided with those of experiment. Consequently, the measurement of the magnetic flux at air gap is one of effective ways to discriminate the faulted conditions of the eccentricity and broken rotor bars.
Comparison of capabilities of reluctance synchronous motor and induction motor
NASA Astrophysics Data System (ADS)
Štumberger, Gorazd; Hadžiselimović, Miralem; Štumberger, Bojan; Miljavec, Damijan; Dolinar, Drago; Zagradišnik, Ivan
2006-09-01
This paper compares the capabilities of a reluctance synchronous motor (RSM) with those of an induction motor (IM). An RSM and IM were designed and made, with the same rated power and speed. They differ only in the rotor portion while their stators, housings and cooling systems are identical. The capabilities of both motors in a variable speed drive are evaluated by comparison of the results obtained by magnetically nonlinear models and by measurements.
Novel rotor position estimation technique for switched reluctance motor (SRM)
NASA Astrophysics Data System (ADS)
Moradi, Hassan; Afjei, Ebrahim
2011-09-01
This article presents a new and novel method which is designed to detect the rotor position at standstill and at low speeds in switched reluctance motor. Since the inductance parameter plays a significant role both in the steady state and in the dynamic characteristics of an electromagnetic device, the rotor position can be determined using inductance bridge systems to measure unknown inductance and resistance values. In this method we use motor winding in Maxwell-Wien Bridge, with the standard capacitor and the resistor in parallel with it adjusted to achieve balance in an aligned position when the maximum inductance occurs. The supply voltage, in conjunction with the drive transistor, produces short pulses for this AC bridge. The condition of the balanced bridge v 0 = 0 leads to the relation between the impedances of the bridge branches. The phase inductance varies with the rotor position. Therefore the motor goes into an unaligned position and the Maxwell-Wien Bridge goes into an unbalanced condition thus causing variation in the state of the bridge output. It then continues to sense the rotor position with the motor running by applying the same procedure, but only to the un-energised phases winding. The simulation and experimentally obtained results demonstrate the feasibility and practicability of this method.
NASA Technical Reports Server (NTRS)
Hansen, Irving G.
1990-01-01
Electromechanical actuators developed to date have commonly utilized permanent magnet (PM) synchronous motors. More recently switched reluctance (SR) motors have been advocated due to their robust characteristics. Implications of work which utilizes induction motors and advanced control techniques are discussed. When induction motors are operated from an energy source capable of controlling voltages and frequencies independently, drive characteristics are obtained which are superior to either PM or SR motors. By synthesizing the machine frequency from a high frequency carrier (nominally 20 kHz), high efficiencies, low distortion, and rapid torque response are available. At this time multiple horsepower machine drives were demonstrated, and work is on-going to develop a 20 hp average, 40 hp peak class of aerospace actuators. This effort is based upon high frequency power distribution and management techniques developed by NASA for Space Station Freedom.
NASA Technical Reports Server (NTRS)
Hansen, Irving G.
1990-01-01
Electromechanical actuators developed to date have commonly ultilized permanent magnet (PM) synchronous motors. More recently switched reluctance (SR) motors have been advocated due to their robust characteristics. Implications of work which utilized induction motors and advanced control techniques are discussed. When induction motors are operated from an energy source capable of controlling voltages and frequencies independently, drive characteristics are obtained which are superior to either PM or SR motors. By synthesizing the machine frequency from a high-frequency carrier (nominally 20 kHz), high efficiencies, low distortion, and rapid torque response are available. At this time multiple horsepower machine drives were demonstrated, and work is on-going to develop a 20 hp average, 40 hp peak class of aerospace actuators. This effort is based upon high-frequency power distribution and management techniques developed by NASA for Space Station Freedom.
NASA Astrophysics Data System (ADS)
Hansen, Irving G.
Electromechanical actuators developed to date have commonly ultilized permanent magnet (PM) synchronous motors. More recently switched reluctance (SR) motors have been advocated due to their robust characteristics. Implications of work which utilized induction motors and advanced control techniques are discussed. When induction motors are operated from an energy source capable of controlling voltages and frequencies independently, drive characteristics are obtained which are superior to either PM or SR motors. By synthesizing the machine frequency from a high-frequency carrier (nominally 20 kHz), high efficiencies, low distortion, and rapid torque response are available. At this time multiple horsepower machine drives were demonstrated, and work is on-going to develop a 20 hp average, 40 hp peak class of aerospace actuators. This effort is based upon high-frequency power distribution and management techniques developed by NASA for Space Station Freedom.
Kelledes, William L.; St. John, Don K.
1992-01-01
The present invention maintains constant torque in an inverter driven AC induction motor during variations in rotor temperature. It is known that the torque output of a given AC induction motor is dependent upon rotor temperature. At rotor temperatures higher than the nominal operating condition the rotor impedance increases, reducing the rotor current and motor torque. In a similar fashion, the rotor impedance is reduced resulting in increased rotor current and motor torque when the rotor temperature is lower than the nominal operating condition. The present invention monitors the bus current from the DC supply to the inverter and adjusts the slip frequency of the inverter drive to maintain a constant motor torque. This adjustment is based upon whether predetermined conditions implying increased rotor temperature or decreased rotor temperature exist for longer that a predetermined interval of time.
Load Characteristics of Induction Motor Manufactured by Soft Magnetic Composite
NASA Astrophysics Data System (ADS)
Fukuda, Tomohiro; Sasaki, Yutaka; Morimoto, Masayuki
The load characteristics of induction motor manufactured by soft magnetic composite (SMC) are presented. We manufactured three kinds of induction motors experimentally. One is a conventional laminated iron core motor. The others are SMC motors. One of the SMC motor uses SMC only for stator, while the other SMC motor uses SMC for stator and rotor. The experimental comparisons of load characteristics and loss analysis are shown. As a result, the difference between the efficiency of the SMC motor and the conventional laminated motor is 4.6%, in spite of the permeability of SMC being 20% lower than the conventional electromagnetic steel.
Prospects for Brushless ac Motors with HTS Rotors
NASA Astrophysics Data System (ADS)
McCulloch, M. D.; Jim, K.; Kawai, Y.; Dew-Hughes, D.; Morgan, C.; Goringe, M. J.; Grovenor, C. R. M.
1997-03-01
There is a superconducting equivalent for every type of brushless ac motor; permanent magnet, reluctance, hysteresis and induction (squirrel cage) motor. The particular advantage of superconducting versions of these machines is that they are expected to provide much higher power densities than their conventional equivalents. The behaviour of superconducting rotors fabricated in the form of (a) squirrell cages from silver coated with melt-processed Bi-2212, (b) tubes cast centifugally from Bi-2212, and (c) small cylinders of melt-processed and seeded YBCO has been studied in rotating magnetic fields provided by conventional motor coils. Measurements of static torque, and values of dynamic torque deduced from angular velocity and acceleration have been used to characterise the potential performance of these embryonic machines. Two broad types of behaviour have been observed. In the Bi-2212 rotors the torque decreases with increasing rotor speed; this behaviour is believed due to flux creep. By contrast the strong-pinning YBCO rotors maintain a constant torque up to synchronous speed. Mathematical modelling of flux penetration and distribution within the rotors is able to reproduce both types of the observed behaviour. Power densities some 5 to 10 times that of conventional machines are predicted to be achievable in optimised prototype machines.
Electromechanical interaction in rotordynamics of cage induction motors
NASA Astrophysics Data System (ADS)
Holopainen, Timo P.; Tenhunen, Asmo; Arkkio, Antero
2005-06-01
Eccentric rotor motion induces an unbalanced magnetic pull between the rotor and stator of cage induction motors. Recently, a linear parametric model of this eccentricity force due to the arbitrary rotor motion was presented. The purpose of this study is to combine this electromagnetic force model with a simple mechanical rotor model, and further, to demonstrate the rotordynamic response induced by this electromechanical interaction. An electromechanical rotor model is derived on the basis of the Jeffcott rotor with two additional variables for the harmonic currents of the rotor cage. Applying this model, the rotordynamic effects of electromechanical interaction were studied. Three induction motors were used in the numerical examples. The electromechanical parameters of these motors were estimated from the numerical simulations carried out separately. The results obtained show that the electromechanical interaction may decrease the natural frequencies of the rotor, induce additional damping or cause rotordynamic instability. These interaction effects are most significant in motors operating at or near the first bending critical speed. Excluding the potential rotordynamic instability, the numerical results indicate that the electromechanical interaction reduces effectively the unbalance response close to the first bending critical speed.
A new approach to detect broken rotor bars in induction machines by current spectrum analysis
NASA Astrophysics Data System (ADS)
Didier, G.; Ternisien, E.; Caspary, O.; Razik, H.
2007-02-01
This paper deals with a new technique to detect broken rotor bars in polyphase induction machines. Like most techniques, we employ the Fourier Transform of the stator current to make detection. But where the other methods use the Fourier Transform modulus, this alternative approach proposes to analyse its phase. As shown by results, the Fourier Transform phase allows to detect one broken rotor bar when the motor operates under a low load but the method robustness decreases for a half-broken rotor bar. So, in order to improve the diagnosis and to permit the detection of incipient broken rotor bar, the analysis is completed with the Hilbert Transform. This transform provides good results and a partially broken rotor bar can be detected when the load torque is equal or greater than 25%. The main advantage of these methods is that the final decision on the rotor cage state is took without the healthy motor reference.
Diagnostics of DC and Induction Motors Based on the Analysis of Acoustic Signals
NASA Astrophysics Data System (ADS)
Glowacz, A.
2014-10-01
In this paper, a non-invasive method of early fault diagnostics of electric motors was proposed. This method uses acoustic signals generated by electric motors. Essential features were extracted from acoustic signals of motors. A plan of study of acoustic signals of electric motors was proposed. Researches were carried out for faultless induction motor, induction motor with one faulty rotor bar, induction motor with two faulty rotor bars and flawless Direct Current, and Direct Current motor with shorted rotor coils. Researches were carried out for methods of signal processing: log area ratio coefficients, Multiple signal classification, Nearest Neighbor classifier and the Bayes classifier. A pattern creation process was carried out using 40 samples of sound. In the identification process 130 five-second test samples were used. The proposed approach will also reduce the costs of maintenance and the number of faulty motors in the industry.
NASA Astrophysics Data System (ADS)
Kong, Xiangxi; Zhang, Xueliang; Chen, Xiaozhe; Wen, Bangchun; Wang, Bo
2016-05-01
In this paper, phase and speed synchronization control of four eccentric rotors (ERs) driven by induction motors in a linear vibratory feeder with unknown time-varying load torques is studied. Firstly, the electromechanical coupling model of the linear vibratory feeder is established by associating induction motor's model with the dynamic model of the system, which is a typical under actuated model. According to the characteristics of the linear vibratory feeder, the complex control problem of the under actuated electromechanical coupling model converts to phase and speed synchronization control of four ERs. In order to keep the four ERs operating synchronously with zero phase differences, phase and speed synchronization controllers are designed by employing adaptive sliding mode control (ASMC) algorithm via a modified master-slave structure. The stability of the controllers is proved by Lyapunov stability theorem. The proposed controllers are verified by simulation via Matlab/Simulink program and compared with the conventional sliding mode control (SMC) algorithm. The results show the proposed controllers can reject the time-varying load torques effectively and four ERs can operate synchronously with zero phase differences. Moreover, the control performance is better than the conventional SMC algorithm and the chattering phenomenon is attenuated. Furthermore, the effects of reference speed and parametric perturbations are discussed to show the strong robustness of the proposed controllers. Finally, experiments on a simple vibratory test bench are operated by using the proposed controllers and without control, respectively, to validate the effectiveness of the proposed controllers further.
Demonstration of Lenz's Law with an Induction Motor
ERIC Educational Resources Information Center
Kraftmakher, Yaakov
2005-01-01
The interaction of a conductor with a time-dependent magnetic field is an important topic of electromagnetic theory. A computerized classroom demonstration shows how the eddy currents induced in the rotor of an induction motor cause its rotation or braking. Both phenomena are directly related to Lenz's law.
Segmented rail linear induction motor
Cowan, Jr., Maynard; Marder, Barry M.
1996-01-01
A segmented rail linear induction motor has a segmented rail consisting of a plurality of nonferrous electrically conductive segments aligned along a guideway. The motor further includes a carriage including at least one pair of opposed coils fastened to the carriage for moving the carriage. A power source applies an electric current to the coils to induce currents in the conductive surfaces to repel the coils from adjacent edges of the conductive surfaces.
Segmented rail linear induction motor
Cowan, M. Jr.; Marder, B.M.
1996-09-03
A segmented rail linear induction motor has a segmented rail consisting of a plurality of nonferrous electrically conductive segments aligned along a guideway. The motor further includes a carriage including at least one pair of opposed coils fastened to the carriage for moving the carriage. A power source applies an electric current to the coils to induce currents in the conductive surfaces to repel the coils from adjacent edges of the conductive surfaces. 6 figs.
Rotor fault condition monitoring techniques for squirrel-cage induction machine—A review
NASA Astrophysics Data System (ADS)
Mehrjou, Mohammad Rezazadeh; Mariun, Norman; Hamiruce Marhaban, Mohammad; Misron, Norhisam
2011-11-01
Nowadays, manufacturing companies are making great efforts to implement an effective machinery maintenance program, which provides incipient fault detection. The machine problem and its irregularity can be detected at an early stage by employing a suitable condition monitoring accompanied with powerful signal processing technique. Among various defects occurred in machines, rotor faults are of significant importance as they cause secondary failures that lead to a serious motor malfunction. Diagnosis of rotor failures has long been an important but complicated task in the area of motor faults detection. This paper intends to review and summarize the recent researches and developments performed in condition monitoring of the induction machine with the purpose of rotor faults detection. The aim of this article is to provide a broad outlook on rotor fault monitoring techniques for the researchers and engineers.
Forward and reverse control system for induction motors
Wright, J.T.
1987-09-15
A control system for controlling the direction of rotation of a rotor of an induction motor includes an array of five triacs with one of the triacs applying a current of fixed phase to the windings of the rotor and four of the triacs being switchable to apply either hot ac current or return ac current to the stator windings so as to reverse the phase of current in the stator relative to that of the rotor and thereby reverse the direction of rotation of the rotor. Switching current phase in the stator is accomplished by operating the gates of pairs of the triacs so as to connect either hot ac current or return ac current to the input winding of the stator. 1 fig.
Disc rotors with permanent magnets for brushless DC motor
Hawsey, Robert A.; Bailey, J. Milton
1992-01-01
A brushless dc permanent magnet motor drives an autonomous underwater vehe. In one embodiment, the motor comprises four substantially flat stators in stacked relationship, with pairs of the stators axially spaced, each of the stators comprising a tape-wound stator coil, and first and second substantially flat rotors disposed between the spaced pairs of stators. Each of the rotors includes an annular array of permanent magnets embedded therein. A first shaft is connected to the first rotor and a second, concentric shaft is connected to the second rotor, and a drive unit causes rotation of the two shafts in opposite directions. The second shaft comprises a hollow tube having a central bore in which the first shaft is disposed. Two different sets of bearings support the first and second shafts. In another embodiment, the motor comprises two ironless stators and pairs of rotors mounted on opposite sides of the stators and driven by counterrotating shafts.
An Estimation Approach for PWM Carrier Loss on Rotor in Slotless Permanent Magnet Motors
NASA Astrophysics Data System (ADS)
Kosaka, Takashi; Shikayama, Toru; Matsui, Nobuyuki
This paper presents an analytical estimation approach for PWM carrier loss on the rotor in the design stage of slotless permanent magnet motors. The experimental studies using 400W, 3000r/min test motor show that the eddy current on the rotor surfaced by rare-earth magnets decreases the winding inductance and increases the winding resistance as the supplied frequency rises. The resultant lower inductance for high frequency over 10kHz produces a large amount of current harmonics caused by voltage PWM as well as the carrier loss combined with the resistance increment. At first, the frequency dependent winding inductance and resistance of test motor are estimated by 3D-finite element method considering the eddy current on the rotor. The current spectrum is subsequently calculated from the obtained frequency dependent winding impedance and the simulated voltage spectrum. The carrier loss is finally derived from the current spectrum and the calculated resistance increment. The effectiveness of the proposed estimation approach for PWM carrier loss on the rotor is experimentally verified using test motor.
Online Monitoring of Induction Motors
McJunkin, Timothy R.; Agarwal, Vivek; Lybeck, Nancy Jean
2016-01-01
The online monitoring of active components project, under the Advanced Instrumentation, Information, and Control Technologies Pathway of the Light Water Reactor Sustainability Program, researched diagnostic and prognostic models for alternating current induction motors (IM). Idaho National Laboratory (INL) worked with the Electric Power Research Institute (EPRI) to augment and revise the fault signatures previously implemented in the Asset Fault Signature Database of EPRI’s Fleet Wide Prognostic and Health Management (FW PHM) Suite software. Induction Motor diagnostic models were researched using the experimental data collected by Idaho State University. Prognostic models were explored in the set of literature and through a limited experiment with 40HP to seek the Remaining Useful Life Database of the FW PHM Suite.
Position Sensing for Rotor in Hybrid Stepper Motor
NASA Technical Reports Server (NTRS)
Howard, David E. (Inventor); Alhorn, Dean C. (Inventor); Smith, Dennis A. (Inventor)
2011-01-01
A method and system are provided for sensing the position of a rotor in a hybrid stepper motor. First and second Hall sensors are positioned in a spaced-apart relationship with the first and second armatures of the rotor such that the first and second Hall sensors generate electrical outputs that are 90.degree. out of phase with one another as the rotor rotates. The electrical outputs are adjusted relative to a reference, and the amplitude of the electrical outputs is further adjusted to account for spacing differences between the rotor and each of the first and second Hall sensors.
Theoretical analysis of a YBCO squirrel-cage type induction motor based on an equivalent circuit
NASA Astrophysics Data System (ADS)
Morita, G.; Nakamura, T.; Muta, I.
2006-06-01
A HTS induction motor, with a HTS squirrel-cage rotor, is analysed using an electrical equivalent circuit. The squirrel-cage winding in the rotor consists of rotor bars and end rings, and both are considered to be made of YBCO film conductors. A wide range of electric field versus current density in YBCO film is formulated based on the Weibull function, and analysed as a non-linear resistance in the equivalent circuit. It is shown that starting and accelerating torques of the HTS induction motor are improved drastically compared to those of a conventional induction motor. Furthermore, large synchronous torque can also be realized by trapping the magnetic flux in the rotor circuit because of the persistent current mode.
Exchange of rotor components in functioning bacterial flagellar motor
Fukuoka, Hajime; Inoue, Yuichi; Terasawa, Shun; Takahashi, Hiroto; Ishijima, Akihiko
2010-03-26
The bacterial flagellar motor is a rotary motor driven by the electrochemical potential of a coupling ion. The interaction between a rotor and stator units is thought to generate torque. The overall structure of flagellar motor has been thought to be static, however, it was recently proved that stators are exchanged in a rotating motor. Understanding the dynamics of rotor components in functioning motor is important for the clarifying of working mechanism of bacterial flagellar motor. In this study, we focused on the dynamics and the turnover of rotor components in a functioning flagellar motor. Expression systems for GFP-FliN, FliM-GFP, and GFP-FliG were constructed, and each GFP-fusion was functionally incorporated into the flagellar motor. To investigate whether the rotor components are exchanged in a rotating motor, we performed fluorescence recovery after photobleaching experiments using total internal reflection fluorescence microscopy. After photobleaching, in a tethered cell producing GFP-FliN or FliM-GFP, the recovery of fluorescence at the rotational center was observed. However, in a cell producing GFP-FliG, no recovery of fluorescence was observed. The transition phase of fluorescence intensity after full or partially photobleaching allowed the turnover of FliN subunits to be calculated as 0.0007 s{sup -1}, meaning that FliN would be exchanged in tens of minutes. These novel findings indicate that a bacterial flagellar motor is not a static structure even in functioning state. This is the first report for the exchange of rotor components in a functioning bacterial flagellar motor.
Analytical and experimental study of high phase order induction motors
NASA Astrophysics Data System (ADS)
Klingshirn, Eugene A.
1989-08-01
Induction motors having more than three phases were investigated to determine their suitability for electric vehicle applications. The objective was to have a motor with a current rating lower than that of a three-phase motor. The name chosen for these is high phase order (HPO) motors. Motors having six phases and nine phases were given the most attention. It was found that HPO motors are quite suitable for electric vehicles, and for many other applications as well. They have characteristics which are as good as or better than three-phase motors for practically all applications where polyphase induction motors are appropriate. Some of the analysis methods are presented, and several of the equivalent circuits which facilitate the determination of harmonic currents and losses, or currents with unbalanced sources, are included. The sometimes large stator currents due to harmonics in the source voltages are pointed out. Filters which can limit these currents were developed. An analysis and description of these filters is included. Experimental results which confirm and illustrate much of the theory are also included. These include locked rotor test results and full-load performance with an open phase. Also shown are oscillograms which display the reduction in harmonic currents when a filter is used with the experimental motor supplied by a non-sinusoidal source.
Analytical and experimental study of high phase order induction motors
NASA Technical Reports Server (NTRS)
Klingshirn, Eugene A.
1989-01-01
Induction motors having more than three phases were investigated to determine their suitability for electric vehicle applications. The objective was to have a motor with a current rating lower than that of a three-phase motor. The name chosen for these is high phase order (HPO) motors. Motors having six phases and nine phases were given the most attention. It was found that HPO motors are quite suitable for electric vehicles, and for many other applications as well. They have characteristics which are as good as or better than three-phase motors for practically all applications where polyphase induction motors are appropriate. Some of the analysis methods are presented, and several of the equivalent circuits which facilitate the determination of harmonic currents and losses, or currents with unbalanced sources, are included. The sometimes large stator currents due to harmonics in the source voltages are pointed out. Filters which can limit these currents were developed. An analysis and description of these filters is included. Experimental results which confirm and illustrate much of the theory are also included. These include locked rotor test results and full-load performance with an open phase. Also shown are oscillograms which display the reduction in harmonic currents when a filter is used with the experimental motor supplied by a non-sinusoidal source.
Analytical calculation of the RFOC method in single-phase induction motor
NASA Astrophysics Data System (ADS)
Jannati, M.; Monadi, A.; Idris, N. R. N.; Faudzi, A. A. M.
2016-05-01
This study discusses the different techniques for speed control of single-phase induction motor with two asymmetrical main and auxiliary windings based on Rotor Field-Oriented Control (RFOC) method. In the presented methods, transformation matrices are introduced and applied to the equations of single-phase induction motor. It is shown by applying these rotational transformations to the unbalanced equations of single-phase induction motor, equations of single-phase induction motor are transformed into symmetrical equations. These rotational transformations are achieved based from the steady-state equivalent circuit of single-phase induction motor. Finally, a method for RFOC of single-phase induction motor is proposed. Results show the good performance of the proposed method.
Three-phase induction motor integrated with a magnetic frequency changer
NASA Astrophysics Data System (ADS)
Goleman, Ryszard
2003-01-01
The new solution of the high-speed induction motor model is presented. The basic structural part of the motor is magnetic circuit with non-linear elements in which the third harmonic of the flux is generated. The finite element method is used to solve the coupled equations for the magnetic field, the stator windings and conductors of the rotor.
Owen, Whitney H.
1980-01-01
A polyphase rotary induction machine for use as a motor or generator utilizing a single rotor assembly having two series connected sets of rotor windings, a first stator winding disposed around the first rotor winding and means for controlling the current induced in one set of the rotor windings compared to the current induced in the other set of the rotor windings. The rotor windings may be wound rotor windings or squirrel cage windings.
Unstable force analysis for induction motor eccentricity
NASA Astrophysics Data System (ADS)
Han, Xu; Palazzolo, Alan
2016-05-01
The increasing popularity of motors in machinery trains has led to an intensified interest in the forces they produce that may influence machinery vibration. Motor design typically assumes a uniform air gap, however in practice all motors operate with the rotor slightly displaced from the motor centerline in what is referred to as an eccentric position. Rotor center eccentricity can cause a radially unbalanced magnetic field when the motor is operating. This will results in both a radial force pulling the motor further away from the center, and a tangential force which can induce a vibration stability problem. In this paper, a magnetic equivalent circuit MEC modeling method is proposed to calculate both the radial and tangential motor eccentric force. The treatment of tangential force determination is rarely addressed, but it is very important for rotordynamic vibration stability evaluation. The proposed model is also coupled with the motor electric circuit model to provide capability for transient vibration simulations. FEM is used to verify the MEC model. A parametric study is performed on the motor radial and tangential eccentric forces. Also a Jeffcott rotor model is used to study the influence of the motor eccentric force on mechanical vibration stability and nonlinear behavior. Furthermore, a stability criteria for the bearing damping is provided. The motor radial and tangential eccentric forces are both curved fitted to include their nonlinearity in time domain transient simulation for both a Jeffcott rotor model and a geared machinery train with coupled torsional-lateral motion. Nonlinear motions are observed, including limit cycles and bifurcation induced vibration amplitude jumps.
Method and system for determining induction motor speed
Parlos, Alexander G.; Bharadwaj, Raj M.
2004-03-30
A non-linear, semi-parametric neural network-based adaptive filter is utilized to determine the dynamic speed of a rotating rotor within an induction motor, without the explicit use of a speed sensor, such as a tachometer, is disclosed. The neural network-based filter is developed using actual motor current measurements, voltage measurements, and nameplate information. The neural network-based adaptive filter is trained using an estimated speed calculator derived from the actual current and voltage measurements. The neural network-based adaptive filter uses voltage and current measurements to determine the instantaneous speed of a rotating rotor. The neural network-based adaptive filter also includes an on-line adaptation scheme that permits the filter to be readily adapted for new operating conditions during operations.
Research on a novel Rotor Structure Switched Reluctance Motor
NASA Astrophysics Data System (ADS)
Zeng, Lingquan; Yu, Haiwei
The paper proposes a novel switched reluctance motor with improved rotor structure, in which the segment core is embedded in aluminum rotor block in order to increase the mechanical strength and easy manufacturing as well as to improve the performance characteristics and reduce the vibration and acoustic noise. The effect of design parameters on the average torque is investigated using the finite element method. Comparison with conventional VR type SRM and segment type SRM without conductive metal construction rotor show the proposed novel SRM has advantages in the torque performances and the vibration and noise characteristics. The performance is also investigated by experiment.
Reluctance network analysis of an orthogonal-core type parametric induction motor
Tajima, Katsubumi; Sato, Kohei; Komukai, Toshihiko; Ichinokura, Osamu
1999-09-01
In this paper, an analytical method of an orthogonal-core type parametric induction motor is proposed, based on a reluctance network model of the stator. The model is derived by a similar technique applied to an orthogonal-core transformer. Using this model the parametric oscillation characteristic of the motor, without a rotor, is computed. The simulation results agree well with the experiments. It is obvious that the analytical model of the stator presented here is proper for analysis of the motor and that, by use of this model and suitable analytical model of the rotor, the motor characteristics can be analyzed.
Linearization Method for Starting Control of Speed-Sensorless Vector-Controlled Induction Motors
NASA Astrophysics Data System (ADS)
Fujinami, Kazuki; Kondo, Keiichiro
A linearization method is proposed for controlling the start-up operation of a rotating induction motor. The dynamics of this motor are deteriorated when the starting operation is carried out at high frequencies. In this method, the characteristics of the method are analyzed to reveal that the aforementioned problem is caused by the low equivalent gain of the induced voltage during the rotor flux establishment. A method to compensate for the angle of the rotor-flux-induced voltage vector is proposed to overcome this problem. The proposed method is experimentally verified by a test set, and the influence of changes in the rotor resistance is analyzed.
NASA Astrophysics Data System (ADS)
Laiho, Antti; Tammi, Kari; Orivuori, Juha; Sinervo, Anssi; Zenger, Kai; Arkkio, Antero
In this paper, flexural rotor vibration in a two-pole cage induction machine equipped with a built-in force actuator is examined. The built-in force actuator is based on the self-bearing machine technology in which a supplementary winding is placed in the machine for force production. The built-in force actuator enables active vibration control, but also it enables excitation of the machine for purposes of condition monitoring, for instance. A low-order parametric model is derived for the actuator-rotor system. In the model, the arbitrary eccentric rotor motion is coupled with the voltage-flux equations for the supplementary winding and eccentric rotor cage. Furthermore, based on frequency-domain system identification, a control method is examined for compensating synchronous rotor vibration. Experimental results are given for a two-pole cage induction motor. The main contribution of the article is to couple eccentric rotor motion, the built-in force actuator and the mechanical rotor model to obtain a low-order parametric model of the actuator-rotor system which can be applied to control design for rotor vibration suppression.
Save power in AC induction motors
NASA Technical Reports Server (NTRS)
Nola, F. J.
1977-01-01
Relatively simple and inexpensive circuitry improves power factor and reduces power dissipation in induction motors operating below full load. Electronic control loop conserves energy by reducing voltage applied to lightly loaded motor. Circuit forces motor to run at constant predetermined optimum power factor, regardless of load or line voltage variations. Solid-state switch varies voltage.
Rotor Design of Permanent Magnet Synchronous Motor for Railway Vehicle
NASA Astrophysics Data System (ADS)
Kondo, Minoru; Kondo, Keiichiro; Fujishima, Yasushi; Wakao, Shinji
The permanent magnet synchronous motor (PMSM) is an efficient machine, which has found application over wide power and speed ranges. This paper presents the optimal rotor design of a PMSM for use on a railway vehicle. This design utilizes reluctance torque in order to develop higher torque at starting with low open circuit voltage at high speed.
John G. Cowie; Edwin F. Brush, Jr.; Dale T. Peters; Stephen P. Midson; Darryl J. Van Son
2003-05-01
The objective of the study, Application of High-Temperature Mold Materials to Die Cast Copper Motor Rotor for Improved Efficiency, was to support the Copper Development Association (CDA) in its effort to design, fabricate and demonstrate mold technologies designed to withstand the copper motor rotor die casting environment for an economically acceptable life. The anticipated result from the compiled data and tests were to: (1) identify materials suitable for die casting copper, (2) fabricate motor rotor molds and (3) supply copper rotor motors for testing in actual compressor systems. Compressor manufacturers can apply the results to assess the technical and economical viability of copper rotor motors.
Effect of skewing the rotor teeth on the performance of doubly salient permanent magnet motors
NASA Astrophysics Data System (ADS)
Sheth, N. K.; Sekharbabu, A. R. C.; Rajagopal, K. R.
2006-04-01
This paper presents the effects of skewing the rotor teeth on the performance characteristics such as flux linkage, back emf, phase inductance, and reluctance torque of an 8/6 doubly salient permanent magnet motor using a simple method, which utilizes the results obtained from the two-dimensional finite element analysis. The optimum skewing angle is obtained as 12°-15° for the least ripple torque without much reduction in the back emf. Skewing the rotor teeth of an 8/6 doubly salient permanent magnet motor by 12°-15° will reduce the total harmonic distortion of the back emf profile to 29.69% from the original value of 44.69%. The reduction in the amplitude of the back emf in this case will be 18.79% only.
A simplified scheme for induction motor condition monitoring
NASA Astrophysics Data System (ADS)
Rodríguez, Pedro Vicente Jover; Negrea, Marian; Arkkio, Antero
2008-07-01
This work proposes a general scheme to detect induction motor fault by monitoring the motor current. The scheme is based on signal processing (predictive filters) and soft computing technique (fuzzy logic). The predictive filter is used in order to separate the fundamental component from the harmonic components. Fuzzy logic is used to identify the motor state. Finite element method (FEM) is utilised to generate virtual data that allows to test the proposed technique and foresee the change in the current under different motor conditions. A simple and reliable method for the detection of stator winding failures based on the phase current amplitudes is implemented and tested. The layout has been proved in MATLAB/SIMULINK, with both data from FEM motor simulation program and real measurements. The proposed method has the ability to work with variable speed drives and avoids the detailed spectral analysis of the motor current. This work shows the feasibility of spotting broken rotor bars, eccentricities and inter-turn short-circuit by monitoring the motor currents.
NASA Astrophysics Data System (ADS)
Arkkio, Antero
1987-12-01
A method for the analysis of induction motors based on the combined solution of the magnetic field equations and the circuit equations of the windings is presented. The equations are discretized by the finite element method. The magnetic field is assumed to be two-dimensional. The three-dimensional features, i.e., the skew of the rotor slots and the end-region fields, are taken into account within the two-dimensional formulation. The general time-dependence of the field and the motion of the rotor are modelled correctly in a step-by-step solution. The amount of computation is reduced significantly if the time-dependence is assumed to be sinusoidal and phasor quantities are used in the solution. The method is applied to the calculation of a cage rotor motor and of a solid rotor motor. The sinusoidal approximation gives good results in the computation of steady-state locked-rotor quantities, but it does not model the motion of the rotor properly. The step-by-step method is used for computing machine quantities in steady and transient states. The operation of the solid rotor motor supplied by a static frequency converter is simulated. The results obtained by the method agree well with the measured ones.
Concept for sleeve induction motor with 1-msec mechanical time constant
NASA Technical Reports Server (NTRS)
Wiegand, D. E.
1968-01-01
Conductive sleeve induction motor having a 1-msec mechanical time constant is used with solid-state devices to control all-electric servo power systems. The servomotor rotor inertia is small compared to the maximum force rating of the servo motion, permitting high no-load acceleration.
Design optimization of axially laminated rotors for synchronous reluctance motors
NASA Astrophysics Data System (ADS)
Wakao, S.; Nishimura, Y.; Ando, H.; Onuki, T.
2000-05-01
This article describes a design optimization of an axially laminated rotor of the synchronous reluctance motor, using the optimization method combined with the magnetic field analysis. The magnetic flux distribution in the synchronous reluctance motor is distorted due to the complicated rotor configuration and the influence of magnetic saturation, which results in a large number of local minimum solutions. Therefore, taking account of the magnetic saturation by the finite element method, the authors propose a novel optimization approach by coupling the stochastic search method with the deterministic one. In the optimization process a suitable objective function for the stability of machine performances is also proposed. Finally some numerical results that demonstrate the validity of the proposed approach are presented.
An Inverter-Driven Induction Motor System with a Deadlock Breaking Capability
NASA Astrophysics Data System (ADS)
Ichikawa, Takuto; Yoshida, Toshiya; Miyashita, Osamu
Induction motors are very widely used in various industrial applications. In semiconductor manufacturing processes, deadlock failure of pumps may occur by the adhering of glass material contained in the gas to the rotor. This can lead to the shutdown of the manufacturing plant. Therefore, a countermeasure to prevent deadlocking of a motor is required. This paper proposes a method for generating an impulse torque in an induction motor fed by an inverter. The proposed inverter circuit is composed of a conventional inverter and a few additional relays. The on-and-off control of the relays supplies an appropriate magnetizing current and a large torque current from the dc-link capacitor. In experiment, a 1.5-kW cage-type induction motor generated a torque that was approximately seven times larger than the rated torque of the motor. This large impulse torque is useful for breaking the motor deadlock.
Four quadrant control of induction motors
NASA Technical Reports Server (NTRS)
Hansen, Irving G.
1991-01-01
Induction motors are the nation's workhorse, being the motor of choice in most applications due to their simple rugged construction. It has been estimated that 14 to 27 percent of the country's total electricity use could be saved with adjustable speed drives. Until now, induction motors have not been suited well for variable speed or servo-drives, due to the inherent complexity, size, and inefficiency of their variable speed controls. Work at NASA Lewis Research Center on field oriented control of induction motors using pulse population modulation method holds the promise for the desired drive electronics. The system allows for a variable voltage to frequency ratio which enables the user to operate the motor at maximum efficiency, while having independent control of both the speed and torque of an induction motor in all four quadrants of the speed torque map. Multiple horsepower machine drives were demonstrated, and work is on-going to develop a 20 hp average, 40 hp peak class of machine. The pulse population technique, results to date, and projections for implementation of this existing new motor control technology are discussed.
Stability synthesis of control system in current fed inverter driven induction motor
Veda, R.; Irisa, T.; Ito, T.; Mochizuki, T.; Sonoda, T.
1983-01-01
This paper presents a new method of synthesizing a stabilizing control system in current fed inverter driven induction motor (CFIDIM). The method is focused on rotor dynamics and a concept of ''damping torque coefficient (DTC)'' is introduced concerning the electrical torque. At first the control system is synthesized on the assumption that an induction motor is driven by an ideally controllable current source. Then perturbed linearized technique indicates that the system can be stabilized if the stator current or frequency is controlled so as to make the DTC positive by feeding back a signal composed of rotor speed. Next, based on this fact, an approach of synthesizing the converter output voltage is presented under a fixed stator frequency. This result clarifies that the stable operation can be achieved by controlling the voltage in proportion to the acceleration of rotor speed or the deviation of electrical torque. These analytical results are verified with laboratory field tests.
Control of rotor motion in a light-driven molecular motor: towards a molecular gearbox.
Ter Wiel, Matthijs K J; van Delden, Richard A; Meetsma, Auke; Feringa, Ben L
2005-11-21
Controlled intramolecular movement and coupling of motor and rotor functions is exerted by this new molecular device. The rate of rotation of the rotor part of the molecule can be adjusted by alteration of the conformation of the motor part of the molecule. For all states of the motor part, different rates of rotation were measured for the rotor part. Conversion between the four propeller orientations was achieved by irradiation and heating. PMID:16267585
Rotor compound concept for designing an industrial HTS synchronous motor
NASA Astrophysics Data System (ADS)
Kashani, M.; Hosseina, M.; Sarrafan, K.; Darabi, A.
2013-06-01
Recently, producing power with smaller amount of losses become as a goal in our daily life. Today, large amount of energy waste in power networks all around the world. The main reason is “resistive electric equipments” of power networks. Since early 1980s, simultaneous with the development of high temperature superconductive (HTS) technology, superconductors gently attracted the mankind attentions. Using superconductive equipments instead of conventional resistive ones are result in salient electric loss reduction in power systems. Especially to reduce losses in power networks superconductive industrial rotating machines can potentially perform a significant role. In early recent century, first generation of HTS rotating machines was born. But unfortunately they have long way to penetrate the commercial markets yet. In HTS rotating machines the conventional copper made windings are replaced with the HTS superconductors. In this paper an industrial HTS synchronous motor with YBCO coated conductor field windings was designed. As a new approach, model was equipped with a compound rotor that includes both magnetic and non-magnetic materials. So, large amount of heavy iron made part was replaced by light non-magnetic material such as G-10 fiberglass. Furthermore, in this structure iron loss in rotor could be reduced to its lowest value. Also less weight and more air gap energy density were the additional advantages. Regarding zero electric loss production in field windings and less iron loss in rotor construction, this model potentially is more effective than the other iron made HTS motors.
FORTRAN program for induction motor analysis
NASA Technical Reports Server (NTRS)
Bollenbacher, G.
1976-01-01
A FORTRAN program for induction motor analysis is described. The analysis includes calculations of torque-speed characteristics, efficiency, losses, magnetic flux densities, weights, and various electrical parameters. The program is limited to three-phase Y-connected, squirrel-cage motors. Detailed instructions for using the program are given. The analysis equations are documented, and the sources of the equations are referenced. The appendixes include a FORTRAN symbol list, a complete explanation of input requirements, and a list of error messages.
INSPECTION MEANS FOR INDUCTION MOTORS
Williams, A.W.
1959-03-10
an appartus is descripbe for inspcting electric motors and more expecially an appartus for detecting falty end rings inn suqirrel cage inductio motors while the motor is running. In its broua aspects, the mer would around ce of reference tedtor means also itons in the phase ition of the An electronic circuit for conversion of excess-3 binary coded serial decimal numbers to straight binary coded serial decimal numbers is reported. The converter of the invention in its basic form generally coded pulse words of a type having an algebraic sign digit followed serially by a plurality of decimal digits in order of decreasing significance preceding a y algebraic sign digit followed serially by a plurality of decimal digits in order of decreasing significance. A switching martix is coupled to said input circuit and is internally connected to produce serial straight binary coded pulse groups indicative of the excess-3 coded input. A stepping circuit is coupled to the switching matrix and to a synchronous counter having a plurality of x decimal digit and plurality of y decimal digit indicator terminals. The stepping circuit steps the counter in synchornism with the serial binary pulse group output from the switching matrix to successively produce pulses at corresponding ones of the x and y decimal digit indicator terminals. The combinations of straight binary coded pulse groups and corresponding decimal digit indicator signals so produced comprise a basic output suitable for application to a variety of output apparatus.
Effects of time-varying loads on rotor fault detection in induction machines
Schoen, R.R.; Habetler, T.G.
1995-07-01
This paper addresses the problem of motor current spectral analysis for the detection of nonidealities in the air gap flux density when in the presence of an oscillating or position-varying load torque. Several schemes have been proposed for the detection of air gap eccentricities and broken rotor bars. The analysis of these effects, however, generally assumes that the load torque is constant. If the load torque varies with the rotational speed, then the motor current spectral harmonics produced by the load will overlap the harmonics caused by the fault conditions. The motor current spectral components in the presence of various fault and load conditions are reviewed. The interaction of the effects on the actual stator current spectrum caused by the fault condition and the torque oscillations are shown to be separable only if the angular position of the fault with respect to the load torque characteristic is known. This is an important result in the formulation of an on-line fault detection scheme that measures only a single phase of the stator current. Since the spatial location of the fault is not known, its influence on a specific current harmonic component cannot be separated from the load effects. Therefore, on-line detection schemes must rely on monitoring a multiple frequency signature and identifying those components not obscured by the load effect. Experimental results which show the current spectra of an induction machine under eccentric air gap and broken rotor bar conditions are given for both fixed and oscillating loads.
Three-Dimensional Temperature Field Simulation for the Rotor of an Asynchronous Motor
ERIC Educational Resources Information Center
Wang, Yanwu; Fan, Chunli; Yang, Li; Sun, Fengrui
2010-01-01
A three-dimensional heat transfer model is built according to the rotor structure of an asynchronous motor, and three-dimensional temperature fields of the rotor under different working conditions, such as the unloaded, rated loaded and that with broken rotor bars, are studied based on the finite element numerical method and experiments. The…
Sensorless speed estimation of an AC induction motor by using an artificial neural network approach
NASA Astrophysics Data System (ADS)
Alkhoraif, Abdulelah Ali
Sensorless speed detection of an induction motor is an attractive area for researchers to enhance the reliability of the system and to reduce the cost of the components. This paper presents a simple method of estimating a rotational speed by utilizing an artificial neural network (ANN) that would be fed by a set of stator current frequencies that contain some saliency harmonics. This approach allows operators to detect the speed in induction motors such an approach also provides reliability, low cost, and simplicity. First, the proposed method is based on converting the stator current signals to the frequency domain and then applying a tracking algorithm to the stator current spectrum in order to detect frequency peaks. Secondly, the ANN has to be trained by the detected peaks; the training data must be from very precise data to provide an accurate rotor speed. Moreover, the desired output of the training is the speed, which is measured by a tachometer simultaneously with the stator current signal. The databases were collected at many different speeds from two different types of AC induction motors, wound rotor and squirrel cage. They were trained and tested, so when the difference between the desired speed value and the ANN output value reached the wanted accuracy, the system does not need to use the tachometer anymore. Eventually, the experimental results show that in an optimal ANN design, the speed of the wound rotor induction motor was estimated accurately, where the testing average error was 1 RPM. The proposed method has not succeeded to predict the rotor speed of the squirrel cage induction motor precisely, where the smallest testingaverage error that was achieved was 5 RPM.
Harmonic Electromagnetic Forces in Induction Motors
NASA Astrophysics Data System (ADS)
Ishibashi, Fuminori; Matsushita, Makoto; Noda, Shinichi
Recently, there has been increasing demand for quiet motors, and the same trend has been observed in the case of induction motors. In induction motors, electromagnetic noise is sometimes the predominant acoustic noise. In small motors, the major cause of vibration and noise is electromagnetic forces resulting from the combination of harmonic fluxes in the air gap. In this study, the spatial distribution of fundamental and harmonic time electromagnetic forces was studied by using search coils, by performing FEM analysis, and by using conventional equations. In a four-pole 2.2kW motor, harmonic electromagnetic forces were measured using 36 search coils on the inner surface of the stator teeth, and the spatial distribution of electromagnetic forces was obtained at each time harmonic frequency. Spatial distribution was also analyzed by FEM, and the results were analytically validated by using conventional equations. On the basis of these analyses, the spatial distribution of electromagnetic forces for various time harmonics was confirmed. These results can be used in the design and development of quiet motors.
Rotor Displacement of the Ultrasonic Motor Having an Angular Displacement Self-Correction Function
NASA Astrophysics Data System (ADS)
Chen, Xiaoduo; Kusakabe, Chiharu; Tomikawa, Yoshiro; Takano, Takehiro
1993-09-01
This paper deals with the experimental investigation for confirmation of rotor displacement of the ultrasonic stepping motor having an angular displacement self-correction function. The experiment focused on the relationship between the rotor’s vibration displacement and its staying position for the self-correction. The result proved that the rotor always stays at the position where the displacement is smallest by cutting a slit into the rotor. Moreover, it has also been found that the stable self-correction of rotor angular displacement depends upon both the rotor driving frequency and rotor clamping force.
An Experimental Research on Vector Control of Induction Motor Based on Simple Model
NASA Astrophysics Data System (ADS)
Zhang, Yinhai; Ge, Jinfa; Liu, Weixia; Wang, Qin
Given the heavy computation, easy saturation and cumulate errors of conventional direct vector control, the vector control of induction motor based on simple model is studied and the detailed scheme is described on the basis of the decomposing and approximating the rotor flux. Because of the direct closed-loop control of the magnetizing current and the torque current and the complex current regulator is completed by PI regulator, so the direct vector control of induction motor is simplified. The experimental results show that the proposed method is effective in decreasing the dynamic disturbance and has the advantages of the simplicity of the code program, rare saturation and shocks.
Variable speed induction motor operation from a 20-kHz power bus
NASA Technical Reports Server (NTRS)
Hansen, Irving G.
1989-01-01
Induction motors are recognized for their simple rugged construction. To date, however, their application to variable speed or servo drives was hampered by limitations on their control. Induction motor drives tend to be complex and to display troublesome low speed characteristics due in part to nonsinusoidal driving voltages. A technique was developed which involves direct synthesis of sinusoidal driving voltages from a high frequency power bus and independent control of frequency and voltages. Separation of frequency and voltage allows independent control of rotor and stator flux, full four quadrant operation, and instantaneous torque control. Recent test results, current status of the technology, and proposed aerospace applications will be discussed.
Fault diagnosis in induction motors using radial magnetic field measurement with an antenna
NASA Astrophysics Data System (ADS)
Belkhayat, D.; Romary, R.; El Adnani, M.; Corton, R.; Brudny, J. F.
2003-09-01
In this paper the emf induced in a search coil is measured in order to detect faults in an induction motor. Anomalous operations caused by a broken rotor bar or a faulty stator cutting phase are analysed. Starting from a theoretical analysis of the radial field spectrum associated with these faults, the measurement of the corresponding emf in the search antenna is examined. The saturation and harmonic components of the permeance produced by the slotting effect are taken into account. Their interactions are analysed, allowing the identification of the frequencies which are of interest for the detection of stator cutting phase faults in a working induction motor.
Variable speed induction motor operation from a 20-kHz power bus
NASA Technical Reports Server (NTRS)
Hansen, Irving G.
1989-01-01
Induction motors are recognized for their simple rugged construction to date, however, their application to variable speed or servo drives has been hampered by limitations on their control. Induction motor drives tend to be complex and to display troublesome low speed characteristics due in part to nonsinusoidal driving voltages. A technique was developed which involves direct synthesis of sinusoidal driving voltages from a high frequency power bus and independent control of frequency and voltages. Separation offrequency and voltage allows independent control of rotor and stator flux, full four-quadrant operation, and instantaneous torque control. Recent test results, current status of the technology, and proposed aerospace applications will be discussed.
Field oriented control of induction motors
NASA Technical Reports Server (NTRS)
Burrows, Linda M.; Zinger, Don S.; Roth, Mary Ellen
1990-01-01
Induction motors have always been known for their simple rugged construction, but until lately were not suitable for variable speed or servo drives due to the inherent complexity of the controls. With the advent of field oriented control (FOC), however, the induction motor has become an attractive option for these types of drive systems. An FOC system which utilizes the pulse population modulation method to synthesize the motor drive frequencies is examined. This system allows for a variable voltage to frequency ratio and enables the user to have independent control of both the speed and torque of an induction motor. A second generation of the control boards were developed and tested with the next point of focus being the minimization of the size and complexity of these controls. Many options were considered with the best approach being the use of a digital signal processor (DSP) due to its inherent ability to quickly evaluate control algorithms. The present test results of the system and the status of the optimization process using a DSP are discussed.
Analytical analysis of single- and three-phase induction motors
Davey, K.R.
1998-09-01
The analysis of single and multiphase induction motors continues to represent a challenge to researchers in computational electromagnetics due to the presence of r{Omega} x B electric fields. This contribution cannot be inserted into the Green`s function for boundary element codes; finite difference and finite element approaches are forced to hard code these effects, compensating at high speeds with upwinding techniques. The direct computation of these affects using transfer relations in a linear environment offers an analytical backdrop both for benchmark testing numerical codes and for design assessment criteria. In addition to torque-speed predictions, the terminal relations and total power dissipation in the rotor are computed for an exposed winding three-phase and single-phase machine.
Control system for a wound-rotor motor
Ellis, James N.
1983-01-01
A load switching circuit for switching two or more transformer taps under load carrying conditions includes first and second parallel connected bridge rectifier circuits which control the selective connection of a direct current load to taps of a transformer. The first bridge circuit is normally conducting so that the load is connected to a first tap through the first bridge circuit. To transfer the load to the second tap, a switch is operable to connect the second bridge circuit to a second tap, and when the second bridge circuit begins to conduct, the first bridge circuit ceases conduction because the potential at the second tap is higher than the potential at the first tap, and the load is thus connected to the second tap through the second bridge circuit. The load switching circuit is applicable in a motor speed controller for a wound-rotor motor for effecting tap switching as a function of motor speed while providing a stepless motor speed control characteristic.
Lyapunov exponent for aging process in induction motor
NASA Astrophysics Data System (ADS)
Bayram, Duygu; Ünnü, Sezen Yıdırım; Şeker, Serhat
2012-09-01
focused on the controlling the mechanical parameters of the electrical machines. Brushless DC motor (BLDCM) and the other general purpose permanent magnet (PM) motors are the most widely examined motors [1, 8, 9]. But the researches, about Lyapunov Exponent, subjected to the induction motors are mostly focused on the control theory of the motors. Flux estimation of rotor, external load disturbances and speed tracking and vector control position system are the main research areas for induction motors [10, 11, 12-14]. For all the data sets which can be collected from an induction motor, vibration data have the key role for understanding the mechanical behaviours like aging, bearing damage and stator insulation damage [15-18]. In this paper aging of an induction motor is investigated by using the vibration signals. The signals consist of new and aged motor data. These data are examined by their 2 dimensional phase portraits and the geometric interpretation is applied for detecting the Lyapunov Exponents. These values are compared in order to define the character and state estimation of the aging processes.
Adaptive speed/position control of induction motor based on SPR approach
NASA Astrophysics Data System (ADS)
Lee, Hou-Tsan
2014-11-01
A sensorless speed/position tracking control scheme for induction motors is proposed subject to unknown load torque via adaptive strictly positive real (SPR) approach design. A special nonlinear coordinate transform is first provided to reform the dynamical model of the induction motor. The information on rotor fluxes can thus be derived from the dynamical model to decide on the proportion of input voltage in the d-q frame under the constraint of the maximum power transfer property of induction motors. Based on the SPR approach, the speed and position control objectives can be achieved. The proposed control scheme is to provide the speed/position control of induction motors while lacking the knowledge of some mechanical system parameters, such as the motor inertia, motor damping coefficient, and the unknown payload. The adaptive control technique is thus involved in the field oriented control scheme to deal with the unknown parameters. The thorough proof is derived to guarantee the stability of the speed and position of control systems of induction motors. Besides, numerical simulation and experimental results are also provided to validate the effectiveness of the proposed control scheme.
Analysis of axially non-uniform loss distribution in 3-phase induction motor considering skew effect
Kown, B.I.; Kim, B.T.; Jun, C.S.; Park, S.C. )
1999-05-01
This paper discusses the phenomena of the axially non-uniform distribution of magnetic flux densities and losses in a 3-phase squirrel cage induction motor of which the rotor bars are skewed. A 2-dimensional complex finite element method taking account of the effects of the skewed rotor bars is utilized for the analysis of characteristics such as copper and iron losses and the loss distributions are examined. The summing up values of non-uniform losses resulted from the finite element analysis are compared with measurement values.
Capacitance and Inductance based Rotor Ground Fault Location Method for Synchronous Machines
NASA Astrophysics Data System (ADS)
Palanisamy, Ramanathan
2016-06-01
This paper presents a capacitance and inductance based rotor ground fault location method for synchronous machines, which can detect and locate the ground fault in the rotor. The main contribution of this technique is to find the location of the ground fault in the rotor winding and reduce the repair time. This detection method is based on the measurement of inductance and capacitance of the rotor winding. It is suitable for salient pole synchronous machines. This method has been validated through experimental tests at the site.
NASA Astrophysics Data System (ADS)
Othman, Syed Muhammad Naufal bin Syed; Sulaiman, Erwan bin; Husin, Zhafir Aizat; Khan, Faisal; Mazlan, Mohamed Mubin Aizat
2015-05-01
This paper proposes an initial design of 12 slot, 10 pole outer-rotor field-excitation flux switching motor (FEFSM) with two different rotor width based from 2 different formula to design the rotor width. Hence, initial design include the three coil test to determine the U, W, V-phase, the flux strengthening and weakening, flux at various armature coil and field-excitation coil current, and finally the torque at various JA and JE. As for the materials, the stator and rotor consists of steel sheets made of electromagnetic steels, copper for armature coils and field excitation coils as the only field for magnetic flux source. There will be some design specification and restriction on outer-rotor FEFSM based on 2D-Finite Element Analysis will be applied to design the proposed machine.
NASA Astrophysics Data System (ADS)
Lasaad, Sbita; Dalila, Zaltni; Naceurq, Abdelkrim Mohamed
This study demonstrates that high performance speed control can be obtained by using an adaptative sliding mode control method for a direct vector controlled Squirrel Cage Induction Motor (SCIM). In this study a new method of designing a simple and effective adaptative sliding mode rotational speed control law is developed. The design includes an accurate sliding mode flux observation from the measured stator terminals and rotor speed. The performance of the Direct Field-Orientation Control (DFOC) is ensured by online tuning based on a Model Reference Adaptative System (MRAS) rotor time constant estimator. The control strategy is derived in the sense of Lyapunov stability theory so that the stable tracking performance can be guaranteed under the occurrence of system uncertainties and external disturbances. The proposed scheme is a solution for a robust and high performance induction motor servo drives. Simulation results are provided to validate the effectiveness and robustness of the developed methodology.
Steady-state, lumped-parameter model for capacitor-run, single-phase induction motors
Umans, S.D.
1996-01-01
This paper documents a technique for deriving a steady-state, lumped-parameter model for capacitor-run, single-phase induction motors. The objective of this model is to predict motor performance parameters such as torque, loss distribution, and efficiency as a function of applied voltage and motor speed as well as the temperatures of the stator windings and of the rotor. The model includes representations of both the main and auxiliary windings (including arbitrary external impedances) and also the effects of core and rotational losses. The technique can be easily implemented and the resultant model can be used in a wide variety of analyses to investigate motor performance as a function of load, speed, and winding and rotor temperatures. The technique is based upon a coupled-circuit representation of the induction motor. A notable feature of the model is the technique used for representing core loss. In equivalent-circuit representations of transformers and induction motors, core loss is typically represented by a core-loss resistance in shunt with the magnetizing inductance. In order to maintain the coupled-circuit viewpoint adopted in this paper, this technique was modified slightly; core loss is represented by a set of core-loss resistances connected to the ``secondaries`` of a set of windings which perfectly couple to the air-gap flux of the motor. An example of the technique is presented based upon a 3.5 kW, single-phase, capacitor-run motor and the validity of the technique is demonstrated by comparing predicted and measured motor performance.
Control for stabilizing the alignment position of the rotor of a synchronous motor
Donley, Lawrence I.
1988-01-01
A method and apparatus for damping oscillations in the rotor load angle of a synchronous motor to provide stable rotational alignment in high precision applications. The damping method includes sensing the angular position of the rotor and utilizing the position signal to generate an error signal in response to changes in the period of rotation of the rotor. The error signal is coupled to phase shift amplifiers which shift the phase of the motor drive signal in a direction to damp out the oscillations in the rotor load angle.
Control for stabilizing the alignment position of the rotor of the synchronous motor
Donley, L.I.
1985-03-12
A method and apparatus is described for damping oscillations in the rotor load angle of a synchronous motor to provide stable rotational alignment in high precision applications. The damping method includes sensing the angular position of the rotor and utilizing the position signal to generate an error signal in response to changes in the period of rotation of the rotor. The error signal is coupled to phase shift amplifiers which shift the phase of the motor drive signal in a direction to damp out the oscillations in the rotor load angle.
Improvements of Power Factor and Torque of a Synchronous Reluctance Motor with a Slit Rotor
NASA Astrophysics Data System (ADS)
Nashiki, Masayuki; Inoue, Yoshimitu; Kawai, Youichi; Yokochi, Takanori; Satake, Akiyoshi; Okuma, Shigeru
Power factor and torque of synchronous reluctance motors with a slit rotor are studied. In there stators, divided teeth made of powder magnetic core are adopted and windings are improved to get high space factor of stator windings and to shorten coil ends. In there rotors, stainless sheets are inserted among soft magnetic metal sheets with adhesive to strengthen the rotors and rotor structure is improved to enlarge the saliency ratio (Ld/Lq). As the result, the power factor 0.78 and 1.6 times torque at same motor size are attained.
A thermal network model for induction motors of hermetic reciprocating compressors
NASA Astrophysics Data System (ADS)
Dutra, T.; Deschamps, C. J.
2015-08-01
This paper describes a simulation model for small reciprocating compressors with emphasis on the electrical motor modelling. Heat transfer is solved through algebraic equations derived from lumped thermal energy balances applied to the compressor components. Thermal conductances between the motor components are characterized via a thermal network model. The single-phase induction motor is modelled via an equivalent circuit, allowing predictions for the motor performance and distributed losses. The predicted temperature distribution is used to evaluate the stator and rotor windings resistances. The thermal and electric models are solved in a coupled manner with a model for the compression cycle. Predictions of temperature distribution, motor efficiency, as well as isentropic and volumetric efficiencies, are compared with experimental data at different operating conditions. The model is then applied to analyse the motor temperature as a function of input voltage and stator wire diameter.
Identifying three-phase induction motor faults using artificial neural networks
Kolla; Varatharasa
2000-01-01
This paper presents an artificial neural network (ANN) based technique to identify faults in a three-phase induction motor. The main types of faults considered are overload, single phasing, unbalanced supply voltage, locked rotor, ground fault, over-voltage and under-voltage. Three-phase currents and voltages from the induction motor are used in the proposed approach. A feedforward layered neural network structure is used. The network is trained using the backpropagation algorithm. The trained network is tested with simulated fault current and voltage data. Fault detection is attempted in the no fault to fault transition period. Off-line testing results on a 3 HP induction motor model show that the proposed ANN based method is effective in identifying various types of faults. PMID:11106295
Induction generator-induction motor wind-powered pumping system
Miranda, M.S.; Lyra, R.O.C.; Silva, S.R.
1997-12-31
The energy storage matter plays an important role in wind-electric conversion systems for isolated applications. Having that in mind, two different approaches can be basically considered: either the immediate conversion of the generated electric energy, as in a water pumping system or electric energy storage for later use, as in a battery charging system. Due to some features such as no need of an external reactive power source and, sometimes, a gearbox, permanent-magnet synchronous generators have been broadly used in low rated power isolated systems. Despite that, system performance can be affected when the generator is feeding an inductive load (e.g., an induction motor) under variable-speed-variable-frequency operational conditions. Since there is no effective flux control, motor overload may occur at high wind speeds. Thus, good system performance can be obtained through additional control devices which may increase system cost. Although being rugged and cheap, induction machines always work as a reactive power drain; therefore, they demand an external reactive power source. Considering that, reactive static compensators appear as an attractive alternative to the cost x performance problem. In addition to that, different control strategies can be used so that system performance can be improved.
A New Manufacturing Technology for Induction Machine Copper Rotors
Hsu, J.S.
2001-09-04
The benefits of energy and operational cost savings from using copper rotors are well recognized. The main barrier to die casting copper rotors is short mold life. This paper introduces a new approach for manufacturing copper-bar rotors. Either copper, aluminum, or their alloys can be used for the end rings. Both solid-core and laminated-core rotors were built. High quality joints of aluminum to copper were produced and evaluated. This technology can also be used for manufacturing aluminum bar rotors with aluminum end rings. Further development is needed to study the life time reliability of the joint, to optimize manufacturing fixtures, and to conduct large-rotor tests.
Fuzzy efficiency optimization of AC induction motors
NASA Technical Reports Server (NTRS)
Jani, Yashvant; Sousa, Gilberto; Turner, Wayne; Spiegel, Ron; Chappell, Jeff
1993-01-01
This paper describes the early states of work to implement a fuzzy logic controller to optimize the efficiency of AC induction motor/adjustable speed drive (ASD) systems running at less than optimal speed and torque conditions. In this paper, the process by which the membership functions of the controller were tuned is discussed and a controller which operates on frequency as well as voltage is proposed. The membership functions for this dual-variable controller are sketched. Additional topics include an approach for fuzzy logic to motor current control which can be used with vector-controlled drives. Incorporation of a fuzzy controller as an application-specific integrated circuit (ASIC) microchip is planned.
Investigation of a rotary ultrasonic motor using a longitudinal vibrator and spiral fin rotor.
Peng, Taijiang; Wu, Xiaoyu; Liang, Xiong; Shi, Hongyan; Luo, Feng
2015-08-01
A Langevin transducer can provide longitudinal vibration with larger amplitude while also possessing a greater fatigue life than other types of piezoelectric vibrators. A novel rotary Ultrasonic Motor (USM) was proposed based on the use of a longitudinal transducer (acting as the stator) and a spiral fin rotor: the front cover of the Langevin transducer was designed as a double-layer cup-shaped structure, with the rotor sustained by the inner-layer, and the bearing cover fixed to the outer-layer; the rotor consisted of a shaft and spiral fins which acted as the elastic coupler. It is different from a traditional traveling USM, because the stator provides longitudinal vibration and the rotor generates the elliptical motion. This paper analyzed the motion locus equation of the fin contact points. Additionally, a theoretical analysis was performed in regards to the mechanism and the motor's rotor motion characteristics, which demonstrates the relationships among the motor's driving force, the torque, the revolution speed, and the motor structure parameters. A motor prototype has been manufactured and surveyed to demonstrate the motor performance. The relationships between the amplitude and the preload on the rotor, the free revolution speed, and the torque of the motor have also been studied. PMID:25971158
Direct Rotor-Position Estimation Method for Salient Pole PM Motor by Using High-Frequency Voltage
NASA Astrophysics Data System (ADS)
Ito, Masato; Kinpara, Yoshihiko
Recently, a number of methods have been proposed for estimating the rotor position of a salient pole PM motor, and methods using a high-frequency voltage can estimate the rotor position accurately, even at low speeds. In the conventional method, the rotor position is estimated indirectly by minimizing the position error signal associated with the difference between the estimated position and the real one. This paper proposes a novel direct rotor-position estimation method for salient pole PM motors. In this method, a rotating high-frequency voltage is supplied to the motor, and the rotor position is estimated directly from the high-frequency current in the motor.
Power factor control system for AC induction motors
NASA Technical Reports Server (NTRS)
Nola, F. J. (Inventor)
1977-01-01
A power factor control system for use with ac induction motors was designed which samples lines voltage and current through the motor and decreases power input to the motor proportional to the detected phase displacement between current and voltage. This system provides, less power to the motor, as it is less loaded.
NASA Astrophysics Data System (ADS)
Ohara, Masaki; Noguchi, Toshihiko
This paper describes a new method for a rotor position sensorless control of a surface permanent magnet synchronous motor based on a model reference adaptive system (MRAS). This method features the MRAS in a current control loop to estimate a rotor speed and position by using only current sensors. This method as well as almost all the conventional methods incorporates a mathematical model of the motor, which consists of parameters such as winding resistances, inductances, and an induced voltage constant. Hence, the important thing is to investigate how the deviation of these parameters affects the estimated rotor position. First, this paper proposes a structure of the sensorless control applied in the current control loop. Next, it proves the stability of the proposed method when motor parameters deviate from the nominal values, and derives the relationship between the estimated position and the deviation of the parameters in a steady state. Finally, some experimental results are presented to show performance and effectiveness of the proposed method.
Speed and efficiency control of an induction motor with input-output linearization
Wang, W.J.; Wang, C.C.
1999-09-01
A combination of a composite adaptive speed controller and an explicit efficiency control algorithm is proposed to control the speed and power efficiency of the induction motor in this paper. First, the input-output linearization method is used to dynamically decouple the motor speed and rotor flux. Then, a composite adaptive control algorithm is designed to control the speed of the induction motor. At steady-state light-load conditions, the magnetizing current command is adjusted on the basis of the product of magnetizing current command and torque current command such that the steady-state power loss is minimum. A PC-based experimental drive system has been implemented, and some experimental results are provided to demonstrate the effectiveness of the presented approach.
A current monitoring system for diagnosing electrical failures in induction motors
NASA Astrophysics Data System (ADS)
Acosta, G. G.; Verucchi, C. J.; Gelso, E. R.
2006-05-01
Induction motors are critical components in industrial processes. A motor failure may yield an unexpected interruption at the industrial plant, with consequences in costs, product quality, and safety. Many of these faulty situations in three phase induction motors have an electrical reason. Among different detection approaches proposed in the literature, those based on stator current monitoring are advantageous due to its non-invasive properties. One of these techniques resorts to spectrum analysis of machine line current. Another non-invasive technique is the Extended Park's Vector Approach, which allows the detection of inter-turn short circuits in the stator winding. This article presents the development of an on-line current monitoring system that uses both techniques for fault detection and diagnosis in the stator and in the rotor. Based on experimental observations and on the knowledge of the electrical machine, a knowledge-based system was constructed in order to carry out the diagnosis task from these estimated data.
Two simple and novel SISO controllers for induction motors based on adaptive passivity.
Travieso-Torres, Juan C; Duarte-Mermoud, Manuel A
2008-01-01
The design of two single-input single-output (SISO) controllers for induction motors based on adaptive passivity is presented in this paper. The two controllers work together with a field orientation block. Because of the adaptive nature of the proposed controllers, the knowledge of the set motor-load parameters is not needed and robustness under variations of such parameters is guaranteed. Simple proportional controllers for the torque, rotor flux and stator current control loops are used, due to the control simplification given by the use of feedback passive equivalence. A new principle called the "Torque-Flux Control Principle" is also stated in this article, which considerably simplifies the controller design, diminishing the control efforts and avoiding also rotor flux estimation. PMID:17714715
Umans, Stephen D; Nisley, Donald L; Melfi, Michael J
2014-10-28
A line-start synchronous motor has a housing, a rotor shaft, and an output shaft. A soft-start coupling portion is operatively coupled to the output shaft and the rotor shaft. The soft-start coupling portion is configurable to enable the synchronous motor to obtain synchronous operation and to drive, at least near synchronous speed during normal steady state operation of the motor, a load having characteristics sufficient to prevent obtaining normal synchronous operation of the motor when the motor is operatively connected to the load in the absence of the soft-start coupling. The synchronous motor is sufficiently rated to obtain synchronous operation and to drive, at least near synchronous speed during normal steady state operation of the motor, a load having characteristics sufficient to prevent obtaining normal synchronous operation of the motor when the motor is operatively connected to the load in the absence of the soft-start coupling.
Induction Motor Drive System Based on Linear Active Disturbance Rejection Controller
NASA Astrophysics Data System (ADS)
Liu, Liying; Zhang, Yongli; Yao, Qingmei
It is difficult to establish an exact mathematical model for the induction motor and the robustness is poor of the vector control system using PI regulator. This paper adopts the linear active disturbance rejection controller (LADRC) to control inductor motor. LADRC doesn't need the exact mathematical model of motor and it can not only estimate but also compensate the general disturbance that includes the coupling items in model of motor and parameters perturbations by linear extended state observer (LESO), so the rotor flux and torque fully decouple. As a result, the performance is improved. To prove the above control scheme, the proposed control system has been simulated in MATLAB/SIMULINK, and the comparison was made with PID. Simulation results show that LADRC' has better performance and robustness than PID.
NASA Astrophysics Data System (ADS)
Liu, Z. J.; Li, J. T.; Jabbar, M. A.
2006-04-01
In design of permanent magnet motors for high-precision applications, it is sometimes necessary, early in the design stage, to have a detailed analysis of the effect of rotor eccentricity that may result from manufacturing imperfectness or use of fluid dynamic or aerodynamic bearings. This paper presents an analytical model for electromagnetic torque and forces in permanent magnet motors with rotor eccentricity. The model gives an insight to the relationship between the effect of the eccentricity and the other motor design parameters on the electromagnetic forces. It is shown that the calculated magnetic forces obtained from this model agree well with those obtained from numerical simulations that are very computationally demanding.
Matsuse, Kouki; Yoshizumi, Tatsuya; Katsuta, Seiji; Taniguchi, Shotaro
1999-01-01
Stator core loss has significant adverse effects when an induction motor is controlled by the conventional field-oriented method. Therefore, taking core loss into account should make it possible to control the torque very precisely. In this paper, a direct-field-oriented induction motor with a deadbeat rotor flux controller was developed. The method ensures maximum efficiency in the steady state without degradation of the dynamic response. Simulation and experimental results have demonstrated that this method has higher efficiency and good speed response without any degradation in the transient characteristics.
Predictive Direct Torque Control for Induction Motor Drive
NASA Astrophysics Data System (ADS)
Benzaioua, A.; Ouhrouche, M.; Merabet, A.
2008-06-01
A predictive control combined with the direct torque control (DTC) to induction motor drive is presented. A new switching strategy is used in DTC, where the constant switching frequency is taken constant, and the speed tracking is done by a predictive controller. The scheme control is applied to induction motor drive in order to perform the dynamic responses of electromagnetic torque, stator flux and speed. A comparison between the PI controller and predictive controller for speed tracking is done. Results of simulation show that the performance of the proposed control scheme for induction motor drive is accurately achieved.
Zhou, P.; Gilmore, J.; Badics, Z.; Cendes, Z.J.
1998-09-01
A method for accurately predicting the steady-state performance of squirrel cage induction motors is presented. The approach is based on the use of complex two-dimensional finite element solutions to deduce per-phase equivalent circuit parameters for any operating condition. Core saturation and skin effect are directly considered in the field calculation. Corrections can be introduced to include three-dimensional effects such as end-winding and rotor skew. An application example is provided to demonstrate the effectiveness of the proposed approach.
Influence of the inverter characteristics on the iron losses in PWM inverter fed induction motors
Boglietti, A.; Ferraris, P.; Lazzari, M.; Pastorelli, M.
1995-12-31
In this paper the authors deal with the effects of the inverter characteristics on the iron losses increment in induction motors fed by PWM controlled converters. Laboratory tests based on no-load input power measurement were carried out and in order to avoid the influence of mechanical losses and rotor copper losses, difficult to be measured or computed, a special test bench with an unconventional test device was employed. In particular the influence of the following inverter parameters are considered: modulation index; modulation waveform; switching frequency. Complete experimental results are presented and discussed.
Q-Axis Flux-Based Sensorless Vector Control of Induction Motor Taking into Account Iron Loss
NASA Astrophysics Data System (ADS)
Tsuji, Mineo; Chen, Shuo; Kai, Toshihiro; Hamasaki, Shin-Ichi
This paper presents a sensorless vector control system for induction motors by taking into account iron loss, in which a flux-observer-based method is applied. Since the flux observer is constructed in a synchronously rotating reference frame with respect to the rotor flux of a current model and the iron loss resistance of parallel exiting circuit is used, the proposed system is very simple and the compensation of iron loss related to the operating frequency is directly realized while calculating rotor fluxes and slip frequency. The accuracies of estimated torque and speed are improved. The effectiveness of the proposed system has been verified by digital simulation and experimentation.
Counteracting Rotor Imbalance in a Bearingless Motor System with Feedforward Control
NASA Technical Reports Server (NTRS)
Kascak, Peter Eugene; Jansen, Ralph H.; Dever, Timothy; Nagorny, Aleksandr; Loparo, Kenneth
2012-01-01
In standard motor applications, traditional mechanical bearings represent the most economical approach to rotor suspension. However, in certain high performance applications, rotor suspension without bearing contact is either required or highly beneficial. Such applications include very high speed, extreme environment, or limited maintenance access applications. This paper extends upon a novel bearingless motor concept, in which full five-axis levitation and rotation of the rotor is achieved using two motors with opposing conical air-gaps. By leaving the motors' pole-pairs unconnected, different d-axis flux in each pole-pair is created, generating a flux imbalance which creates lateral force. Note this is approach is different than that used in previous bearingless motors, which use separate windings for levitation and rotation. This paper will examine the use of feedforward control to counteract synchronous whirl caused by rotor imbalance. Experimental results will be presented showing the performance of a prototype bearingless system, which was sized for a high speed flywheel energy storage application, with and without feedforward control.
FUZZY LOGIC CONTROL OF AC INDUCTION MOTORS
The paper discusses the fuzzy logic control (FLC) of electric motors, being investigated under the sponsorship of the U.S. EPA to reduce energy consumption when motors are operated at less than rated speeds and loads. lectric motors use 60% of the electrical energy generated in t...
An Induction Motor Based Wind Turbine Emulator
NASA Astrophysics Data System (ADS)
Sokolovs, A.; Grigans, L.; Kamolins, E.; Voitkans, J.
2014-04-01
The authors present a small-scale wind turbine emulator based on the AC drive system and discuss the methods for power coefficient calculation. In the work, the experimental set-up consisting of an AC induction motor, a frequency converter, a synchronous permanent magnet generator, a DC-DC boost converter and DC load was simulated and tested using real-life equipment. The experimentally obtained wind turbine power and torque diagrams using the emulator are in a good agreement with the theoretical ones. Šajā rakstā parādīta mazas jaudas vēja turbīnas emulatora izveide ar maiņstrāvas piedziņas sistēmu, kā arī analizētas vairākas turbīnas jaudas koeficienta analītiskās aprēķina metodes. Vēja turbīnas emulatora eksperimentālais stends, kas sastāv no asinhronā elektromotora, frekvenču pārveidotāja, sinhronā pastāvīgo magnētu ģeneratora, līdzstrāvas paaugstinošā pārveidotāja un slodzes, tika pārbaudīts gan simulēšanas vidē, gan uz reālām iekārtām. Eksperimentāli iegūtās vēja turbīnas emulatora jaudas un momenta diagrammas ir salīdzinātas ar teorētiskajām.
NASA Astrophysics Data System (ADS)
Kucuk, Fuat; Goto, Hiroki; Guo, Hai-Jiao; Ichinokura, Osamu
2009-04-01
Feedback of motor torque is required in most of switched reluctance (SR) motor applications in order to control torque and its ripple. An SR motor shows highly nonlinear property which does not allow calculating torque analytically. Torque can be directly measured by torque sensor, but it inevitably increases the cost and has to be properly mounted on the motor shaft. Instead of torque sensor, finite element analysis (FEA) may be employed for torque calculation. However, motor modeling and calculation takes relatively long time. The results of FEA may also differ from the actual results. The most convenient way seems to calculate torque from the measured values of rotor position, current, and flux linkage while locking the rotor at definite positions. However, this method needs an extra assembly to lock the rotor. In this study, a novel torque calculation based on artificial neural networks (ANNs) is presented. Magnetizing data are collected while a 6/4 SR motor is running. They need to be interpolated for torque calculation. ANN is very strong tool for data interpolation. ANN based torque estimation is verified on the 6/4 SR motor and is compared by FEA based torque estimation to show its validity.
Control system for an induction motor with energy recovery
NASA Technical Reports Server (NTRS)
Nola, F. J. (Inventor)
1983-01-01
A control circuit for an induction motor powered system is disclosed in which a power factor controlled servo loop is used to control, via the phase angle of firing of a triac, the power input to the motor, as a function of load placed on the motor by machinery of the powered system. Then, upon application of torque by this machinery to the motor, which tends to overspeed the motor, the firing angle of the triac is automatically set to a fixed, and relatively short, firing angle.
Design of outer-rotor type multipolar SR motor for electric vehicle
NASA Astrophysics Data System (ADS)
Nakamura, Kenji; Suzuki, Yosuke; Goto, Hiroki; Ichinokura, Osamu
2005-04-01
In this paper, we design an outer-rotor type multipolar switched reluctance (SR) motor, and examine an application of the SR motor to an electric vehicle (EV). The design is based on a nonlinear magnetic circuit model proposed by the authors. Using the model, we can calculate dynamic characteristics of a SR motor accurately. Furthermore, by combining the nonlinear magnetic circuit model with a motor drive circuit and motion equation of an EV, we can predict dynamic characteristics such as the maximum speed, acceleration torque, and a battery current of the EV.
Speed Sensorless Induction Motor Drives for Electrical Actuators: Schemes, Trends and Tradeoffs
NASA Technical Reports Server (NTRS)
Elbuluk, Malik E.; Kankam, M. David
1997-01-01
For a decade, induction motor drive-based electrical actuators have been under investigation as potential replacement for the conventional hydraulic and pneumatic actuators in aircraft. Advantages of electric actuator include lower weight and size, reduced maintenance and operating costs, improved safety due to the elimination of hazardous fluids and high pressure hydraulic and pneumatic actuators, and increased efficiency. Recently, the emphasis of research on induction motor drives has been on sensorless vector control which eliminates flux and speed sensors mounted on the motor. Also, the development of effective speed and flux estimators has allowed good rotor flux-oriented (RFO) performance at all speeds except those close to zero. Sensorless control has improved the motor performance, compared to the Volts/Hertz (or constant flux) controls. This report evaluates documented schemes for speed sensorless drives, and discusses the trends and tradeoffs involved in selecting a particular scheme. These schemes combine the attributes of the direct and indirect field-oriented control (FOC) or use model adaptive reference systems (MRAS) with a speed-dependent current model for flux estimation which tracks the voltage model-based flux estimator. Many factors are important in comparing the effectiveness of a speed sensorless scheme. Among them are the wide speed range capability, motor parameter insensitivity and noise reduction. Although a number of schemes have been proposed for solving the speed estimation, zero-speed FOC with robustness against parameter variations still remains an area of research for speed sensorless control.
Performance Analysis of Saturated Induction Motors by Virtual Tests
ERIC Educational Resources Information Center
Ojaghi, M.; Faiz, J.; Kazemi, M.; Rezaei, M.
2012-01-01
Many undergraduate-level electrical machines textbooks give detailed treatments of the performance of induction motors. Students can deepen this understanding of motor performance by performing the appropriate practical work in laboratories or in simulation using proper software packages. This paper considers various common and less-common tests…
Power factor control system for ac induction motors
NASA Technical Reports Server (NTRS)
Nola, F. J. (Inventor)
1981-01-01
A power control circuit for an induction motor is disclosed in which a servo loop is used to control power input by controlling the power factor of motor operation. The power factor is measured by summing the voltage and current derived square wave signals.
Soft Computing Application in Fault Detection of Induction Motor
Konar, P.; Puhan, P. S.; Chattopadhyay, P. Dr.
2010-10-26
The paper investigates the effectiveness of different patter classifier like Feed Forward Back Propagation (FFBPN), Radial Basis Function (RBF) and Support Vector Machine (SVM) for detection of bearing faults in Induction Motor. The steady state motor current with Park's Transformation has been used for discrimination of inner race and outer race bearing defects. The RBF neural network shows very encouraging results for multi-class classification problems and is hoped to set up a base for incipient fault detection of induction motor. SVM is also found to be a very good fault classifier which is highly competitive with RBF.
Motor power control circuit for ac induction motors
NASA Technical Reports Server (NTRS)
Nola, F. J. (Inventor)
1983-01-01
A motor power control of the type which functions by controlling the power factor wherein one of the parameters of power factor current on time is determined by the on time of a triac through which current is supplied to the motor. By means of a positive feedback circuit, a wider range of control is effected.
Transistorized PWM inverter-induction motor drive system
NASA Technical Reports Server (NTRS)
Peak, S. C.; Plunkett, A. B.
1982-01-01
This paper describes the development of a transistorized PWM inverter-induction motor traction drive system. A vehicle performance analysis was performed to establish the vehicle tractive effort-speed requirements. These requirements were then converted into a set of inverter and motor specifications. The inverter was a transistorized three-phase bridge using General Electric power Darlington transistors. The description of the design and development of this inverter is the principal object of this paper. The high-speed induction motor is a design which is optimized for use with an inverter power source. The primary feedback control is a torque angle control with voltage and torque outer loop controls. A current-controlled PWM technique is used to control the motor voltage. The drive has a constant torque output with PWM operation to base motor speed and a constant horsepower output with square wave operation to maximum speed. The drive system was dynamometer tested and the results are presented.
Zorgani, Youssef Agrebi; Koubaa, Yassine; Boussak, Mohamed
2016-03-01
This paper presents a novel method for estimating the load torque of a sensorless indirect stator flux oriented controlled (ISFOC) induction motor drive based on the model reference adaptive system (MRAS) scheme. As a matter of fact, this method is meant to inter-connect a speed estimator with the load torque observer. For this purpose, a MRAS has been applied to estimate the rotor speed with tuned load torque in order to obtain a high performance ISFOC induction motor drive. The reference and adjustable models, developed in the stationary stator reference frame, are used in the MRAS scheme in an attempt to estimate the speed of the measured terminal voltages and currents. The load torque is estimated by means of a Luenberger observer defined throughout the mechanical equation. Every observer state matrix depends on the mechanical characteristics of the machine taking into account the vicious friction coefficient and inertia moment. Accordingly, some simulation results are presented to validate the proposed method and to highlight the influence of the variation of the inertia moment and the friction coefficient on the speed and the estimated load torque. The experimental results, concerning to the sensorless speed with a load torque estimation, are elaborated in order to validate the effectiveness of the proposed method. The complete sensorless ISFOC with load torque estimation is successfully implemented in real time using a digital signal processor board DSpace DS1104 for a laboratory 3 kW induction motor. PMID:26775088
Chiba, Akira; Fukao, Tadashi
1995-12-31
In this paper, a mathematical analysis based on a simple model is carried out. The operating characteristics of switched reluctance motors fed by square waveform voltage are analyzed. Inductance variations with respect to the rotor rotational position is approximated with only a sinusoidal function and a constant. Square waveform voltage is approximated by a fundamental component only. Based on this simple representation, it is possible to analyze operating characteristics mathematically in normalized planes and to derive a general control method. It is found that there exists a particular voltage phase angle which realizes the maximum output per current. It was also found that the maximum output per voltage can be achieved at the another particular voltage phase angle. These characteristics are found to be very similar to those of synchronous reluctance motors. As a result of the analysis, an efficient operating method is proposed. These results are confirmed by a 6,000 r/min., 2kW prototype machine.
Torsional stress analysis of the squirrel-cage rotor for three phase asynchronous motors
NASA Astrophysics Data System (ADS)
Axinte, T.; Nutu, C.
2015-11-01
The paper aims to determine the torsional stress occurring in the rotor's shaft of the three phase asynchronous motors for a given rotational speed of the rotor. The three phase asynchronous motor is started using the main starting variants, each variant having its own torque characteristic which produces a certain maximum shear stress. The model uses several hypotheses regarding the geometry of the domain, the dynamic behavior, the friction phenomenon and the mass of the shaft which is disregarded in a model and it is considered in a more accurate model. The maximum shear stress is produced by the shock which occurs in the starting process of the motors. This maximum stress may lead to the failure of the rotor either because it breaks, or because of the fatigue of the material produced by frequent starting of the motor. Information resulted from this study are useful for the selection of the appropriate material, of the according geometry of the design and elaboration of the specifications for the in-service use of the motor.This theoretical study will be followed by the development of more accurate models which will also include experimental studies employed to calibrate the theoretical models and to verify their accuracy.
Motor technology for mining applications advances
Fiscor, S.
2009-08-15
AC motors are steadily replacing DC motors in mining and mineral processing equipment, requiring less maintenance. The permanent magnet rotor, or the synchronous motor, has enabled Blador to introduce a line of cooling tower motors. Synchronous motors are soon likely to take over from the induction motor. 1 photo.
NASA Astrophysics Data System (ADS)
Saxena, Anand
The focus of this research was to demonstrate a four blade rotor trim in forward flight using integrated trailing edge flaps instead of using a swashplate controls. A compact brushless DC motor was evaluated as an on-blade actuator, with the possibility of achieving large trailing edge flap amplitudes. A control strategy to actuate the trailing edge flap at desired frequency and amplitude was developed and large trailing edge flap amplitudes from the motor (instead of rotational motion) were obtained. Once the actuator was tested on the bench-top, a lightweight mechanism was designed to incorporate the motor in the blade and actuate the trailing edge flaps. A six feet diameter, four bladed composite rotor with motor-flap system integrated into the NACA 0012 airfoil section was fabricated. Systematic testing was carried out for a range of load conditions, first in the vacuum chamber followed by hover tests. Large trailing edge flap deflections were observed during the hover testing, and a peak to peak trailing edge flap amplitude of 18 degree was achieved at 2000 rotor RPM with hover tip Mach number of 0.628. A closed loop controller was designed to demonstrate trailing edge flap mean position and the peak to peak amplitude control. Further, a soft pitch link was designed and fabricated, to replace the stiff pitch link and thereby reduce the torsional stiffness of the blade to 2/rev. This soft pitch link allowed for blade root pitch motion in response to the trailing edge flap inputs. Blade pitch response due to both steady as well as sinusoidal flap deflections were demonstrated. Finally, tests were performed in Glenn L. Martin wind tunnel using a model rotor rig to assess the performance of motor-flap system in forward flight. A swashplateless trim using brushless DC motor actuated trailing edge flaps was achieved for a rotor operating at 1200 RPM and an advance ratio of 0.28. Also, preliminary exploration was carried out to test the scalability of the motor
Fault tolerant vector control of induction motor drive
NASA Astrophysics Data System (ADS)
Odnokopylov, G.; Bragin, A.
2014-10-01
For electric composed of technical objects hazardous industries, such as nuclear, military, chemical, etc. an urgent task is to increase their resiliency and survivability. The construction principle of vector control system fault-tolerant asynchronous electric. Displaying recovery efficiency three-phase induction motor drive in emergency mode using two-phase vector control system. The process of formation of a simulation model of the asynchronous electric unbalance in emergency mode. When modeling used coordinate transformation, providing emergency operation electric unbalance work. The results of modeling transient phase loss motor stator. During a power failure phase induction motor cannot save circular rotating field in the air gap of the motor and ensure the restoration of its efficiency at rated torque and speed.
Indirect rotor position sensing in real time for brushless permanent magnet motor drives
Ertugrul, N.; Acarnley, P.P.
1998-07-01
This paper describes a modern solution to real-time rotor position estimation of brushless permanent magnet (PM) motor drives. The position estimation scheme, based on flux linkage and line-current estimation, is implemented in real time by using the abc reference frame, and it is tested dynamically. The position estimation model of the test motor, development of hardware, and basic operation of the digital signal processor (DSP) are discussed. The overall position estimation strategy is accomplished with a fast DSP (TMS320C30). The method is a shaft position sensorless method that is applicable to a wide range of excitation types in brushless PM motors without any restriction on the motor model and the current excitation. Both rectangular and sinewave-excited brushless PM motor drives are examined, and the results are given to demonstrate the effectiveness of the method with dynamic loads in closed estimated position loop.
Flux-Based Deadbeat Control of Induction-Motor Torque
NASA Technical Reports Server (NTRS)
Kenny, Barbara H.; Lorenz, Robert D.
2003-01-01
An improved method and prior methods of deadbeat direct torque control involve the use of pulse-width modulation (PWM) of applied voltages. The prior methods are based on the use of stator flux and stator current as state variables, leading to mathematical solutions of control equations in forms that do not lend themselves to clear visualization of solution spaces. In contrast, the use of rotor and stator fluxes as the state variables in the present improved method lends itself to graphical representations that aid in understanding possible solutions under various operating conditions. In addition, the present improved method incorporates the superposition of high-frequency carrier signals for use in a motor-self-sensing technique for estimating the rotor shaft angle at any speed (including low or even zero speed) without need for additional shaft-angle-measuring sensors.
Improved magnetic field analysis of induction motor models
Enokizono, Masato; Sadanaga, Yuichiro
1998-09-01
This paper presents an improved magnetic field analysis for induction motor models. In the analysis with the conventional numerical modeling of magnetic materials, the vector relations between the flux density and the field intensity under a rotating field cannot be expressed exactly. In this paper, the authors derived the tensor magnetic reluctivity from the data measured with two-dimensional measurement method. This expression is applied to analyze a three-phase induction motor model core. The examples show that the calculated results obtained by the new method are different from those of the conventional modeling.
Bearing Fault Detection in Induction Motor-Gearbox Drivetrain
NASA Astrophysics Data System (ADS)
Cibulka, Jaroslav; Ebbesen, Morten K.; Robbersmyr, Kjell G.
2012-05-01
The main contribution in the hereby presented paper is to investigate the fault detection capability of a motor current signature analysis by expanding its scope to include the gearbox, and not only the induction motor. Detecting bearing faults outside the induction motor through the stator current analysis represents an interesting alternative to traditional vibration analysis. Bearing faults cause changes in the stator current spectrum that can be used for fault diagnosis purposes. A time-domain simulation of the drivetrain model is developed. The drivetrain system consists of a loaded single stage gearbox driven by a line-fed induction motor. Three typical bearing faults in the gearbox are addressed, i.e. defects in the outer raceway, the inner raceway, and the rolling element. The interaction with the fault is modelled by means of kinematical and mechanical relations. The fault region is modelled in order to achieve gradual loss and gain of contact. A bearing fault generates an additional torque component that varies at the specific bearing defect frequency. The presented dynamic electromagnetic dq-model of an induction motor is adjusted for diagnostic purpose and considers such torque variations. The bearing fault is detected as a phase modulation of the stator current sine wave at the expected bearing defect frequency.
Transient effects in application of PWM inverters to induction motors
Persson, E. )
1992-10-01
Standard squirrel cage induction (SCI) motors are subjected to nonsinusoidal waveshapes when supplied form adjustable-frequency inverters. In addition to causing increased heating, these wave patterns can be destructive to the insulation. In particular, pulse width modulated (PWM) inverter output amplitudes and rise times are investigated. Motor insulation capabilities are discussed. In this paper, voltage reflections are simulated for various cable lengths and rise times and are presented graphically. Simulations confirm potential problems with long cables and short rise times.
NASA Astrophysics Data System (ADS)
Enomoto, Yuji; Miyata, Kenji; Oonishi, Kazuo; Motegi, Yasuaki
The three-dimensional magnetic field analysis has clarified the effect of several structural and manufacturing factors on the properties of the outer rotor type stepping motors. (1) The number of rotor teeth, 128, can make a unit step angle under 0.5 degree and a cogging torque under 1mNm for the outer rotor type stepping motor with the outer diameter under 60mm and with the output torque above 0.4Nm. (2) The permanent magnet flux has an optimal value dependent on the thickness of the laminated core to maximize the motor torque. (3) The lamination stacking error of the small teeth of the rotor and stator has a large effect on the cogging torque of the stepping motor.
HTS axial flux induction motor with analytic and FEA modeling
NASA Astrophysics Data System (ADS)
Li, S.; Fan, Y.; Fang, J.; Qin, W.; Lv, G.; Li, J. H.
2013-11-01
This paper presents a high-temperature superconductor (HTS) axial-flux induction motor, which can output levitation force and torque simultaneously. In order to analyze the character of the force, analytic method and finite element method are adopted to model the motor. To make sure the HTS can carry sufficiently large current and work well, the magnetic field distribution in HTS coil is calculated. An effective method to improve the critical current of HTS coil is presented. Then, AC losses in HTS windings in the motor are estimated and tested.
Induction motor inter turn fault detection using infrared thermographic analysis
NASA Astrophysics Data System (ADS)
Singh, Gurmeet; Anil Kumar, T. Ch.; Naikan, V. N. A.
2016-07-01
Induction motors are the most commonly used prime movers in industries. These are subjected to various environmental, thermal and load stresses that ultimately reduces the motor efficiency and later leads to failure. Inter turn fault is the second most commonly observed faults in the motors and is considered the most severe. It can lead to the failure of complete phase and can even cause accidents, if left undetected or untreated. This paper proposes an online and non invasive technique that uses infrared thermography, in order to detect the presence of inter turn fault in induction motor drive. Two methods have been proposed that detect the fault and estimate its severity. One method uses transient thermal monitoring during the start of motor and other applies pseudo coloring technique on infrared image of the motor, after it reaches a thermal steady state. The designed template for pseudo-coloring is in acquiescence with the InterNational Electrical Testing Association (NETA) thermographic standard. An index is proposed to assess the severity of the fault present in the motor.
Field-Oriented Control Of Induction Motors
NASA Technical Reports Server (NTRS)
Burrows, Linda M.; Roth, Mary Ellen; Zinger, Don S.
1993-01-01
Field-oriented control system provides for feedback control of torque or speed or both. Developed for use with commercial three-phase, 400-Hz, 208-V, 5-hp motor. Systems include resonant power supply operating at 20 kHz. Pulse-population-modulation subsystem selects individual pulses of 20-kHz single-phase waveform as needed to synthesize three waveforms of appropriate lower frequency applied to three phase windings of motor. Electric actuation systems using technology currently being built to peak powers of 70 kW. Amplitude of voltage of effective machine-frequency waveform determined by momentary frequency of pulses, while machine frequency determined by rate of repetition of overall temporal pattern of pulses. System enables independent control of both voltage and frequency.
Supply-pollution (SP) loss in induction motor
Hsu, J.S.
1995-07-01
Power supply in the field is often noticeably polluted with various degrees of harmonics content and unbalanced voltages. In order to assess the energy loss caused by the supply pollution in the widely used induction motors, a method based on the air-gap torque power is discussed.
A novel induction motor starting method using superconduction
NASA Astrophysics Data System (ADS)
Silva, F. B. B.; Orlando, M. T. D.; Fardin, J. F.; Simonetti, D. S.; Baldan, C. A.
2014-12-01
In this paper, an alternative method for starting up induction motors is proposed, taking into account experimental measurements. The new starting current limitation method is based on using a high-temperature superconductor. A prototype of the superconducting starting current limiter was constructed with a commercially available second-generation high-temperature superconductor YBCO tape, and this was tested with a 55-kW industrial induction motor in a 440-V/60-Hz three-phase power grid. Performance evaluations of the superconducting limiter method (applied to startup of the induction motor) were performed and were compared with a direct-on-line starter and an electronic soft starter. In addition, a computational model was developed and used for electromagnetic torque analysis of the system. As significant characteristics, our method offers the ability to limit the starting current of the induction motor with greater electromagnetic torque, reduced current waveform distortion and therefore lower harmonic pollution during startup when compared to the soft starter method.
Close up of backup exciter showing induction motor at left ...
Close up of backup exciter showing induction motor at left and direct current generator at right. View to west - Mystic Lake Hydroelectric Facility, Powerhouse, Along West Rosebud Creek, 1 3/4 miles northeast of Mystic Lake Dam, Fishtail, Stillwater County, MT
Hashim, P K; Thomas, Reji; Tamaoki, Nobuyuki
2011-06-20
New phototriggered molecular machines based on cyclic azobenzene were synthesized in which a 2,5-dimethoxy, 2,5-dimethyl, 2,5-difluorine or unsubstituted-1,4-dioxybenzene rotating unit and a photoisomerizable 3,3'-dioxyazobenzene moiety are bridged together by fixed bismethylene spacers. Depending upon substitution on the benzene moiety and on the E/Z conformation of the azobenzene unit, these molecules suffer various degrees of restriction on the free rotation of the benzene rotor. The rotation of the substituted benzene rotor within the cyclic azobenzene cavity imparts planar chirality to the molecules. Cyclic azobenzene 1, with methoxy groups at both the 2- and 5-positions of the benzene rotor, was so conformationally restricted that free rotation of the rotor was prevented in both the E and Z isomers and the respective planar chiral enantiomers were resolved. In contrast, compound 2, with 2,5-dimethylbenzene as the rotor, demonstrated the property of a light-controlled molecular brake, whereby rotation of the 2,5-dimethylbenzene moiety is completely stopped in the E isomer (brake ON, rotation OFF), while the rotation is allowed in the Z isomer (brake OFF, rotation ON). The cyclic azobenzene 3, with fluorine substitution on the benzene rotor, was in the brake OFF state regardless of E/Z photoisomerization of the azobenzene moiety. More interestingly, for the first time, we demonstrated the induction of molecular chirality in a simple monocyclic azobenzene by circular-polarized light. The key characteristics of cyclic azobenzene 2, that is, stability of the chiral structure in the E isomer, fast racemization in the Z isomer, and the circular dichroism of enantiomers of both E and Z isomers, resulted in a simple reversible enantio-differentiating photoisomerization directly between the E enantiomers. Upon exposure to r- or l-circularly polarized light at 488 nm, partial enrichment of the (S)- or (R)-enantiomers of 2 was observed. PMID:21567494
Analysis of a three phase induction motor directly from Maxwell's equations
NASA Astrophysics Data System (ADS)
Bhattacharjee, Shayak
2012-01-01
The torque developed in a three phase AC squirrel cage motor is usually expressed in terms of resistances and reactances of the stator, the rotor, and the motor as a whole. We use Maxwell's equations to find the torque in terms of geometrical parameters. This formulation allows us to estimate the torque developed by a motor without knowing the details of its circuitry.
Quantitative analysis of noninvasive diagnostic procedures for induction motor drives
NASA Astrophysics Data System (ADS)
Eltabach, Mario; Antoni, Jerome; Najjar, Micheline
2007-10-01
This paper reports quantitative analyses of spectral fault components in five noninvasive diagnostic procedures that use input electric signals to detect different types of abnormalities in induction motors. Besides the traditional one phase current spectrum analysis "SC", the diagnostic procedures based on spectrum analysis of the instantaneous partial powers " P ab", " P cb", total power " P abc", and the current space vector modulus " csvm" are considered. The aim of this comparison study is to improve the diagnosis tools for detection of electromechanical faults in electrical machines by using the best suitable diagnostic procedure knowing some motor and fault characteristics. Defining a severity factor as the increase in amplitude of the fault characteristic frequency, with respect to the healthy condition, enables us to study the sensitivity of the electrical diagnostic tools. As a result, it is shown that the relationship between the angular displacement of the current side-bands components at frequencies ( f± fosc) is directly related to the type of induction motor faults. It is also proved that the total instantaneous power diagnostic procedure was observed to exhibit the highest values of the detection criterion in case of mechanical faults while in case of electrical ones the most reliable diagnostic procedure is tightly related to the value of the motor power factor angle and the group motor-load inertia. Finally, simulation and experimental results show good agreement with the fault modeling theoretical results.
Cai, K; Yu, J Z; Yin, H; Qin, Q H
2015-03-01
In a thermally driven rotary motor made from double-walled carbon nanotubes, the rotor (inner tube) can be actuated to rotate within the stator (outer tube) when the environmental temperature is high enough. A sudden stoppage of the rotor can occur when the inner tube has been actuated to rotate at a stable high speed. To find the mechanisms of such sudden stoppages, eight motor models with the same rotor but different stators are built and simulated in the canonical NVT ensembles. Numerical results demonstrate that the sudden stoppage of the rotor occurs when the difference between radii is near 0.34 nm at a high environmental temperature. A smaller difference between radii does not imply easier activation of the sudden rotor stoppage. During rotation, the positions and electron density distribution of atoms at the ends of the motor show that a sp(1) bonded atom on the rotor is attracted by the sp(1) atom with the biggest deviation of radial position on the stator, after which they become two sp(2) atoms. The strong bond interaction between the two atoms leads to the loss of rotational speed of the rotor within 1 ps. Hence, the sudden stoppage is attributed to two factors: the deviation of radial position of atoms at the stator's ends and the drastic thermal vibration of atoms on the rotor in rotation. For a stable motor, sudden stoppage could be avoided by reducing deviation of the radial position of atoms at the stator's ends. A nanobrake can be, thus, achieved by adjusting a sp1 atom at the ends of stator to stop the rotation of rotor quickly. PMID:25676848
Nonlinear servo control of an induction motor with saturation
Bodson, M.; Chiasson, J.; Novotnak, R.
1994-12-31
This work is an extension of the authors` previous work on high-performance induction motor control in which the magnetic model of the motor was assumed to be linear. Saturation of the iron in the main path of the induction machine is taken into account. The saturation is modeled in the dq coordinate frame and the model is then used to design an input-output linearization controller to provide independent (decoupled) control of the speed and flux. With this controller, the flux reference becomes an extra degree of freedom for the designer to help achieve performance objectives. Taking into account saturation, the flux reference is chosen to achieve the optimal torque (maximum for acceleration & minimum for deceleration) at any given speed. The input-output controller is used to provide tracking of a given position & speed trajectory while simultaneously tracking the optimal flux reference. Experimental results are given to validate the approach.
NASA Astrophysics Data System (ADS)
Antonino-Daviu, J.; Jover, P.; Riera, M.; Arkkio, A.; Roger-Folch, J.
2007-08-01
The behaviour of an induction machine during a startup transient can provide useful information for the diagnosis of electromechanical faults. During this process, the machine works under high stresses and the effects of the faults may also be larger than those in steady-state. These facts may help to amplify the magnitude of the indicators of some incipient faults. In addition, fault components with frequencies dependant on the slip evolve in a particular way during that transient, a fact that allows the diagnosis of the corresponding fault and the discrimination between different faults. The discrete wavelet transform (DWT) is an ideal tool for analysing signals with frequency spectrum variable in time. Some research works have applied with success the DWT to the stator startup current in order to diagnose the presence of broken rotor bars in induction machines. However, few works have used this technique for the study of other common faults, such as eccentricities. In this work, time-frequency analysis of the stator startup current is carried out in order to detect the presence of dynamic eccentricities in an induction motor. For this purpose, the DWT is applied and wavelet signals at different levels are studied. Data are obtained from simulations, using a finite element (FE) model of an induction motor, which allows forcing several kinds of faults in the machine, and also from experimental tests. The results show the validity of the approach for detecting the fault and discriminating with respect to other failures, presenting for certain applications (or working conditions) some advantages over the traditional stationary analysis.
Voltage oscillatory instability caused by induction motor loads
Mello, F.P. de; Feltes, J.W.
1996-08-01
Isolated power systems which fit the structure of a single equivalent generator supplying an equivalent composite load can experience a voltage oscillatory instability entirely traceable to effects of induction motor loads interacting with automatic voltage regulators. This scenario is one where an AVR properly tuned for open circuit conditions is not necessarily well tuned for the on load condition. The phenomenon is explained and a simple solution through AVR compensation is suggested.
Optimized performance of solar powered variable speed induction motor drive
Singh, B.N.; Singh, B.P.; Singh, B.; Chandra, A.; Al-Haddad, K.
1995-12-31
This paper deals with the design and development of a photo voltaic (PV) array fed cage induction motor for an isolated water pumping system. A drive system using a chopper circuit to track maximum power from the PV for different solar insolation and a current controlled voltage source inverter (CC-VSI) to optimally match the motor to PV characteristics is presented. The model equations governing interaction of torque and flux producing components of motor current with available solar power is developed for the operation of the system at optimum efficiency. Performance of the system is presented for different realistic operating conditions, which demonstrates its special features for applications such as solar water pumping system, solar vehicles and floor mills located in hilly and isolated areas.
Ac hysteresis loop measurement of stator-tooth in induction motor
Son, D.
1999-09-01
The properties of ac hysteresis loop of a stator tooth in a 5 hp induction motor was measured and analyzed. The load increase on the motor decreased magnetic induction, however increase the minor hysteresis loops in the high induction region. This effect caused increase in the core loss. Depending on condition of the motor, the core loss of the stator tooth can be 50% greater than the core loss under sinusoidal magnetic induction waveform.
NASA Technical Reports Server (NTRS)
Morrison, Carlos R.; Siebert, Mark W.; Ho, Eric J.
2007-01-01
Analysis and experimental measurement of the electromagnet force loads on the hybrid rotor in a novel bearingless switched-reluctance motor (BSRM) have been performed. A BSRM has the combined characteristics of a switched-reluctance motor and a magnetic bearing. The BSRM has an eight-pole stator and a six-pole hybrid rotor, which is composed of circular and scalloped lamination segments. The hybrid rotor is levitated using only one set of stator poles. A second set of stator poles imparts torque to the scalloped portion of the rotor, which is driven in a traditional switched reluctance manner by a processor. Analysis was done for nonrotating rotor poles that were oriented to achieve maximum and minimum radial force loads on the rotor. The objective is to assess whether simple one-dimensional magnetic circuit analysis is sufficient for preliminary evaluation of this machine, which may exhibit strong three-dimensional electromagnetic field behavior. Two magnetic circuit geometries, approximating the complex topology of the magnetic fields in and around the hybrid rotor, were employed in formulating the electromagnetic radial force equations. Reasonable agreement between the experimental results and the theoretical predictions was obtained with typical magnetic bearing derating factors applied to the predictions.
Evaluation of quasi-square wave inverter as a power source for induction motors
NASA Technical Reports Server (NTRS)
Guynes, B. V.; Haggard, R. L.; Lanier, J. R., Jr.
1977-01-01
The relative merits of quasi-square wave inverter-motor technology versus a sine wave inverter-motor system were investigated. The empirical results of several tests on various sizes of wye-wound induction motors are presented with mathematical analysis to support the conclusions of the study. It was concluded that, within the limitations presented, the quasi-square wave inverter-motor system is superior to the more complex sine wave system for most induction motor applications in space.
Effect of Pressing Force Applied to a Rotor on Disk-Type Ultrasonic Motor Driven by Self-Oscillation
NASA Astrophysics Data System (ADS)
Kusakabe, Chiharu; Tomikawa, Yoshiro; Takahashi, Sadayuki; Takano, Takehiro
1998-05-01
In this paper the relationship between the pressing force applied to a rotor and the rotation characteristic of an ultrasonic motor driven by self-oscillation are discussed.The motor used here is an in-phase drive-type ultrasonic motor using two degenerate bending vibration modes of a disk.The picking-up electrical signal caused by self-oscillation is positively fed back into the piezoelectric ceramics for driving through an operational amplifier and a step-up transformer. The pressing force applied to a rotor was measured using a force gauge coupled to the shaft of the ultrasonic motor. As a result, it was confirmed that the selection of the picking-up position for the feedback signal is important for a stable starting and running of the disk-type ultrasonic motor driven by self-oscillation.
NASA Astrophysics Data System (ADS)
Chiariotti, P.; Ciarmatori, R.; Castellini, P.; Bastari, A.; Paone, N.
2012-06-01
When designing a test bench for vibration based diagnostics of machines with external rotating parts, such as electric motors having a rotating external rotor, one may choose among single point vibrometry, rotational vibrometry or in-plane vibrometry. The paper discusses these different options, taking the assumption that the minimum number of measuring instruments is preferred when instrumenting a quality control system and provides an insight into advantages and limitations of each instrument. In particular the following issues are discussed: a) possible installation lay-outs; b) alignment problems (and possible advantages for diagnostics), c) typical signals and diagnostic features which can be observed. The research presented refers to electric motors for home appliances, but potentially has wider application fields to other rotating machines.
Metamodels for New Designs of Outer-Rotor Brushless Synchronous Electric Motors
NASA Astrophysics Data System (ADS)
Dirba, J.; Lavrinovicha, L.
2014-04-01
The authors consider the possibilities to synthesise metamodels for the analysis and optimisation of brushless synchronous motors. The metamodels are presented for new designs of the outer-rotor permanent magnet synchronous motor and the outer-rotor reluctance motor. The metamodels are synthesised based on the results obtained by the numerical calculations of magnetic field taking into account magnetic saturation. Analysis of the results for the motor magnetic field and tests of the metamodels at the selected and intermediate points shows that these can be synthesised with acceptable accuracy using numerical calculations instead of expensive real experiments. Rakstā ir apskatītas metamodeļu iegūšanas iespējas to izmantošanai bezkontaktu sinhrono dzinēju analīzē un optimizācijā. Ir iegūti metamodeļi sinhronam dzinējam ar pastāvīgajiem magnētiem un reaktīvam dzinējam ar ārējo rotoru. Sintezēto metamodeļu iegūšanai izmantoti elektrisko dzinēju magnētiskā lauka skaitlisko aprēķinu rezultāti, ievērojot magnētiskās ķēdes piesātinājumu. Metamodeļu pārbaude aprēķinu un starppunktos parādīja, ka to iegūšanai dārgo reālo eksperimentu vietā var izmantot magnētiskā lauka aprēķinu rezultātus.
Empirical mode decomposition and neural networks on FPGA for fault diagnosis in induction motors.
Camarena-Martinez, David; Valtierra-Rodriguez, Martin; Garcia-Perez, Arturo; Osornio-Rios, Roque Alfredo; Romero-Troncoso, Rene de Jesus
2014-01-01
Nowadays, many industrial applications require online systems that combine several processing techniques in order to offer solutions to complex problems as the case of detection and classification of multiple faults in induction motors. In this work, a novel digital structure to implement the empirical mode decomposition (EMD) for processing nonstationary and nonlinear signals using the full spline-cubic function is presented; besides, it is combined with an adaptive linear network (ADALINE)-based frequency estimator and a feed forward neural network (FFNN)-based classifier to provide an intelligent methodology for the automatic diagnosis during the startup transient of motor faults such as: one and two broken rotor bars, bearing defects, and unbalance. Moreover, the overall methodology implementation into a field-programmable gate array (FPGA) allows an online and real-time operation, thanks to its parallelism and high-performance capabilities as a system-on-a-chip (SoC) solution. The detection and classification results show the effectiveness of the proposed fused techniques; besides, the high precision and minimum resource usage of the developed digital structures make them a suitable and low-cost solution for this and many other industrial applications. PMID:24678281
Empirical Mode Decomposition and Neural Networks on FPGA for Fault Diagnosis in Induction Motors
Garcia-Perez, Arturo; Osornio-Rios, Roque Alfredo; Romero-Troncoso, Rene de Jesus
2014-01-01
Nowadays, many industrial applications require online systems that combine several processing techniques in order to offer solutions to complex problems as the case of detection and classification of multiple faults in induction motors. In this work, a novel digital structure to implement the empirical mode decomposition (EMD) for processing nonstationary and nonlinear signals using the full spline-cubic function is presented; besides, it is combined with an adaptive linear network (ADALINE)-based frequency estimator and a feed forward neural network (FFNN)-based classifier to provide an intelligent methodology for the automatic diagnosis during the startup transient of motor faults such as: one and two broken rotor bars, bearing defects, and unbalance. Moreover, the overall methodology implementation into a field-programmable gate array (FPGA) allows an online and real-time operation, thanks to its parallelism and high-performance capabilities as a system-on-a-chip (SoC) solution. The detection and classification results show the effectiveness of the proposed fused techniques; besides, the high precision and minimum resource usage of the developed digital structures make them a suitable and low-cost solution for this and many other industrial applications. PMID:24678281
Prediction of induction motor line current spectra from design data
NASA Astrophysics Data System (ADS)
Guldemir, Hanifi
The thesis concentrates on the estimation of the magnitude and frequency of the spectral components of line current that may be used for sensorless speed detection. The prediction method uses a mixture of permeance-mmf, finite element and reluctance mesh techniques to establish the air gap magnetic field. This traditional type of approach is chosen to maintain a visible link between cause and effect so enhancing understanding. The approach is enhanced by the use of slot permanence effects calculated by finite element techniques where saturation due to the current carrying conductors in the slots is incorporated. This is essential for closed slots. Further enhancements include examining slot permeance effects over one or more poles so that the influence of the spatial distribution of slot currents, and slot top saturation can be incorporated. The harmonic chain equivalent circuit is extensively modified to provide a vehicle for predicting the correct saturation conditions in a skewed machine and the correct winding currents for the field solutions. Rotor pole aliasing is introduced to explain the large number of independent speed harmonic terms found experimentally. Special equivalent circuits are introduced to enable these current harmonic to be predicted. A thorough experimental validation is then conducted of the model using a 30 kW experimental machine with adjustable eccentricity with rotors of different slotting form, slot number and skew to determine their effect on the speed dependent harmonic components. Very good agreement is demonstrated. Finally, the improved prediction model is used to provide information on the significance of saturation, skew, slot number and rotor eccentricity on the level of speed dependent harmonic signals. All of this information helps formulate important rules to assist in the choice of motors for satisfactory operation with sensorless speed control of drives using RSH. This in itself is an important extension to the knowledge
Variable-frequency inverter controls torque, speed, and braking in ac induction motors
NASA Technical Reports Server (NTRS)
Nola, F. J.
1974-01-01
Dc to ac inverter provides optimum frequency and voltage to ac induction motor, in response to different motor-load and speed requirements. Inverter varies slip frequency of motor in proportion to required torque. Inverter protects motor from high current surges, controls negative slip to apply braking, and returns energy stored in momentum of load to dc power source.
Augmenting Plasticity Induction in Human Motor Cortex by Disinhibition Stimulation.
Cash, Robin F H; Murakami, Takenobu; Chen, Robert; Thickbroom, Gary W; Ziemann, Ulf
2016-01-01
Cellular studies showed that disinhibition, evoked pharmacologically or by a suitably timed priming stimulus, can augment long-term plasticity (LTP) induction. We demonstrated previously that transcranial magnetic stimulation evokes a period of presumably GABA(B)ergic late cortical disinhibition (LCD) in human primary motor cortex (M1). Here, we hypothesized that, in keeping with cellular studies, LCD can augment LTP-like plasticity in humans. In Experiment 1, patterned repetitive TMS was applied to left M1, consisting of 6 trains (intertrain interval, 8 s) of 4 doublets (interpulse interval equal to individual peak I-wave facilitation, 1.3-1.5 ms) spaced by the individual peak LCD (interdoublet interval (IDI), 200-250 ms). This intervention (total of 48 pulses applied over ∼45 s) increased motor-evoked potential amplitude, a marker of corticospinal excitability, in a right hand muscle by 147% ± 4%. Control experiments showed that IDIs shorter or longer than LCD did not result in LTP-like plasticity. Experiment 2 indicated topographic specificity to the M1 hand region stimulated by TMS and duration of the LTP-like plasticity of 60 min. In conclusion, GABA(B)ergic LCD offers a powerful new approach for augmenting LTP-like plasticity induction in human cortex. We refer to this protocol as disinhibition stimulation (DIS). PMID:25100853
NASA Astrophysics Data System (ADS)
Takahata, Ryoichi; Wakui, Shinichi; Miyata, Kenji; Noma, Keiji; Senoo, Masaharu
Recently, global warming and the problem with successfully incorporating environmental safeguards have promoted the need for a more power-efficient motor. Therefore, as a driving source, permanent magnet synchronous motor (PMSM) with concentrated winding is widely used as the important device for a variety of fields. However, a PMSM with concentrated winding generates more vibrations than that with distributed winding because of a radial electromagnetic force. This paper describes the influence of a new skewed rotor on the characteristics of a concentrated winding PMSM. We investigated the influence by using a three-dimensional finite element analysis (3-D FEM) and several measurements. In addition, we presented that the proposed rotor is effective in reducing the radial electromagnetic force without decreasing the motor efficiency.
NASA Astrophysics Data System (ADS)
Mazlan, Mohamed Mubin Aizat; Sulaiman, Erwan; Husin, Zhafir Aizat; Othman, Syed Muhammad Naufal Syed; Khan, Faisal
2015-05-01
In hybrid excitation machines (HEMs), there are two main flux sources which are permanent magnet (PM) and field excitation coil (FEC). These HEMs have better features when compared with the interior permanent magnet synchronous machines (IPMSM) used in conventional hybrid electric vehicles (HEVs). Since all flux sources including PM, FEC and armature coils are located on the stator core, the rotor becomes a single piece structure similar with switch reluctance machine (SRM). The combined flux generated by PM and FEC established more excitation fluxes that are required to produce much higher torque of the motor. In addition, variable DC FEC can control the flux capabilities of the motor, thus the machine can be applied for high-speed motor drive system. In this paper, the comparisons of single-phase 8S-4P outer and inner rotor hybrid excitation flux switching machine (HEFSM) are presented. Initially, design procedures of the HEFSM including parts drawing, materials and conditions setting, and properties setting are explained. Flux comparisons analysis is performed to investigate the flux capabilities at various current densities. Then the flux linkages of PM with DC FEC of various DC FEC current densities are examined. Finally torque performances are analyzed at various armature and FEC current densities for both designs. As a result, the outer-rotor HEFSM has higher flux linkage of PM with DC FEC and higher average torque of approximately 10% when compared with inner-rotor HEFSM.
NASA Astrophysics Data System (ADS)
Zhu, Z. Q.; Chen, Y.; Howe, D.
2005-05-01
The stator iron loss and rotor eddy current loss which results in a high-speed permanent magnet brushless motor when operated in brushless dc and ac modes, on both open-circuit and at rated load, with four different current control strategies, is investigated by finite element analysis. It has highlighted the significant influence of the phase current wave form. It has also shown that, on load, the rotor eddy current loss can be the dominant loss component, particularly in brushless dc mode.
Speed sensorless hybrid vector controlled induction motor drive
Bose, B.K.; Simoes, M.G.; Crecelius, D.R.; Rajashekara, K.; Martin, R.
1995-12-31
The paper describes a speed and flux sensorless vector-controlled induction motor drive primarily aimed for electric vehicle type applications. The stator flux oriented drive starts at zero speed in indirect vector control mode, transitions to direct vector control mode as the speed develops, and then transitions back to indirect vector control at zero speed. The vector control uses stator flux orientation in both indirect and direct vector control modes with the stator resistance variation compensated by measurement of stator temperature. The problem of integration at low stator frequency is solved by cascaded low pass filters with programmable time constants. The control strategy of the four-quadrant drive has been analyzed, validated by simulation study, and finally evaluated by experimental study on a laboratory 5 hp drive system.
Dynamic Performance of Subway Vehicle with Linear Induction Motor System
NASA Astrophysics Data System (ADS)
Wu, Pingbo; Luo, Ren; Hu, Yan; Zeng, Jing
The light rail vehicle with Linear Induction Motor (LIM) bogie, which is a new type of urban rail traffic tool, has the advantages of low costs, wide applicability, low noise, simple maintenance and better dynamic behavior. This kind of vehicle, supported and guided by the wheel and rail, is not driven by the wheel/rail adhesion force, but driven by the electromagnetic force between LIM and reaction plate. In this paper, three different types of suspensions and their characteristic are discussed with considering the interactions both between wheel and rail and between LIM and reaction plate. A nonlinear mathematical model of the vehicle with LIM bogie is set up by using the software SIMPACK, and the electromechanical model is also set up on Simulink roof. Then the running behavior of the LIM vehicle is simulated, and the influence of suspension on the vehicle dynamic performance is investigated.
Induction motor control system with voltage controlled oscillator circuit
NASA Technical Reports Server (NTRS)
Nola, F. J.; Currie, J. R.; Reid, H., Jr. (Inventor)
1973-01-01
A voltage controlled oscillator circuit is reported in which there are employed first and second differential amplifiers. The first differential amplifier, being employed as an integrator, develops equal and opposite slopes proportional to an input voltage, and the second differential amplifier functions as a comparator to detect equal amplitude positive and negative selected limits and provides switching signals which gate a transistor switch. The integrating differential amplifier is switched between charging and discharging modes to provide an output of the first differential amplifier which upon the application of wave shaping provides a substantially sinusoidal output signal. A two phased version with a second integrator provides a second 90 deg phase shifted output for induction motor control.
FUZZY-LOGIC-BASED CONTROLLERS FOR EFFICIENCY OPTIMIZATION OF INVERTER-FED INDUCTION MOTOR DRIVES
This paper describes a fuzzy-logic-based energy optimizing controller to improve the efficiency of induction motor/drives operating at various load (torque) and speed conditions. Improvement of induction motor efficiency is important not only from the considerations of energy sav...
Magnetically induced rotor vibration in dual-stator permanent magnet motors
NASA Astrophysics Data System (ADS)
Xie, Bang; Wang, Shiyu; Wang, Yaoyao; Zhao, Zhifu; Xiu, Jie
2015-07-01
Magnetically induced vibration is a major concern in permanent magnet (PM) motors, which is especially true for dual-stator motors. This work develops a two-dimensional model of the rotor by using energy method, and employs this model to examine the rigid- and elastic-body vibrations induced by the inner stator tooth passage force and that by the outer. The analytical results imply that there exist three typical vibration modes. Their presence or absence depends on the combination of magnet/slot, force's frequency and amplitude, the relative position between two stators, and other structural parameters. The combination and relative position affect these modes via altering the force phase. The predicted results are verified by magnetic force wave analysis by finite element method (FEM) and comparison with the existing results. Potential directions are also given with the anticipation of bringing forth more interesting and useful findings. As an engineering application, the magnetically induced vibration can be first reduced via the combination and then a suitable relative position.
Neural and Fuzzy Adaptive Control of Induction Motor Drives
Bensalem, Y.; Sbita, L.; Abdelkrim, M. N.
2008-06-12
This paper proposes an adaptive neural network speed control scheme for an induction motor (IM) drive. The proposed scheme consists of an adaptive neural network identifier (ANNI) and an adaptive neural network controller (ANNC). For learning the quoted neural networks, a back propagation algorithm was used to automatically adjust the weights of the ANNI and ANNC in order to minimize the performance functions. Here, the ANNI can quickly estimate the plant parameters and the ANNC is used to provide on-line identification of the command and to produce a control force, such that the motor speed can accurately track the reference command. By combining artificial neural network techniques with fuzzy logic concept, a neural and fuzzy adaptive control scheme is developed. Fuzzy logic was used for the adaptation of the neural controller to improve the robustness of the generated command. The developed method is robust to load torque disturbance and the speed target variations when it ensures precise trajectory tracking with the prescribed dynamics. The algorithm was verified by simulation and the results obtained demonstrate the effectiveness of the IM designed controller.
Neural and Fuzzy Adaptive Control of Induction Motor Drives
NASA Astrophysics Data System (ADS)
Bensalem, Y.; Sbita, L.; Abdelkrim, M. N.
2008-06-01
This paper proposes an adaptive neural network speed control scheme for an induction motor (IM) drive. The proposed scheme consists of an adaptive neural network identifier (ANNI) and an adaptive neural network controller (ANNC). For learning the quoted neural networks, a back propagation algorithm was used to automatically adjust the weights of the ANNI and ANNC in order to minimize the performance functions. Here, the ANNI can quickly estimate the plant parameters and the ANNC is used to provide on-line identification of the command and to produce a control force, such that the motor speed can accurately track the reference command. By combining artificial neural network techniques with fuzzy logic concept, a neural and fuzzy adaptive control scheme is developed. Fuzzy logic was used for the adaptation of the neural controller to improve the robustness of the generated command. The developed method is robust to load torque disturbance and the speed target variations when it ensures precise trajectory tracking with the prescribed dynamics. The algorithm was verified by simulation and the results obtained demonstrate the effectiveness of the IM designed controller.
Variable frequency inverter for ac induction motors with torque, speed and braking control
NASA Technical Reports Server (NTRS)
Nola, F. J. (Inventor)
1975-01-01
A variable frequency inverter was designed for driving an ac induction motor which varies the frequency and voltage to the motor windings in response to varying torque requirements for the motor so that the applied voltage amplitude and frequency are of optimal value for any motor load and speed requirement. The slip frequency of the motor is caused to vary proportionally to the torque and feedback is provided so that the most efficient operating voltage is applied to the motor. Winding current surge is limited and a controlled negative slip causes motor braking and return of load energy to a dc power source.
Field assessment of induction motor efficiency through air-gap torque
Hsu, J.S.; Sorenson, P.L.
1995-11-01
Induction motors are the most popular motors used in industry. This paper further suggests the use of air-gap torque method to evaluate their efficiency and load changes. The fundamental difference between Method E and the air-gap torque method is discussed. Efficiency assessments conducted on induction motors under various conditions show the accuracy and potential of the air-gap torque method.
Fault analysis for condition monitoring of induction motors
NASA Astrophysics Data System (ADS)
Nandi, Subhasis
Recently, research has picked up a fervent pace in the area of fault diagnosis of electrical machines. Like adjustable speed drives, fault prognosis has become almost indispensable. The manufacturers of these drives are now keen to include diagnostic features in the software to decrease machine down time and improve salability. Prodigious improvement in signal processing hardware and software has made this possible. Primarily, these techniques depend upon locating specific harmonic components in the line current, also known as motor current signature analysis (MCSA). These harmonic components are usually different for different types of faults. However, with multiple faults or different varieties of drive schemes, MCSA can become an onerous task as different types of faults and time harmonics may end up generating similar signatures. Thus, other signals such as speed, torque, noise, vibration, etc., are also explored for their frequency contents. Sometimes, altogether different techniques such as thermal measurements, chemical analysis, etc., are also employed to find out the nature and the degree of the fault. It is indeed evident that this area is vast in scope. Going by the present trend, human involvement in the actual fault detection decision making is slowly being replaced by automated tools such as expert systems, neural networks, fuzzy logic based systems; to name a few. However, this cannot be achieved without detailed fault analysis and subsequent recognition of the fault pattern. Keeping this in mind, simulation studies of the broken bar and eccentricity related faults using MCSA have been taken up. Also, a common theoretical basis for the different types (static, dynamic and mixed) of eccentricity related faults which give different signatures for different pole and rotor bar combinations has been developed. This will be of great importance both from fault diagnosis as well as sensorless drive applications' viewpoint. Finally, the insight gained from
Method and apparatus for monitoring the rotating frequency of de-energized induction motors
Mikesell, H.E.; Lucy, E.
1998-02-03
The rotational speed of a coasting induction motor is measured by sensing e residual electrical voltages at the power terminals of the motor, thus eliminating the need for conventional tachometer equipment, additional mechanical components or modifications to the induction motor itself. The power terminal voltage signal is detected and transformed into a DC voltage proportional to the frequency of the signal. This DC voltage can be input to the control system of a variable frequency motor controller to regulate the output characteristics thereof relative to the speed of the coasting motor. 6 figs.
Method and apparatus for monitoring the rotating frequency of de-energized induction motors
Mikesell, Harvey E.; Lucy, Eric
1998-01-01
The rotational speed of a coasting induction motor is measured by sensing e residual electrical voltages at the power terminals of the motor, thus eliminating the need for conventional tachometer equipment, additional mechanical components or modifications to the induction motor itself. The power terminal voltage signal is detected and transformed into a DC voltage proportional to the frequency of the signal. This DC voltage can be input to the control system of a variable frequency motor controller to regulate the output characteristics thereof relative to the speed of the coasting motor.
Isaac, F.N.; Arkadan, A.A.; Russell, A.A.; El-Antably, A.
1998-09-01
In the last few years, increased attention has been paid to the performance characterization and evaluation of the performance of synchronous reluctance machines. Extensive research has concentrated on different rotor structures in order to achieve high performance variable speed drives for applications such as electric vehicles. The effects of accounting for anisotropy on the performance characteristics of Axially Laminated Anisotropic (ALA) rotor Synchronous Reluctance Motor (SynRM) drive systems are studied. These effects are evaluated from the simulations of a computer aided model. The model is based on the use of an iterative approach which indirectly couples a two dimensional (2D) nonlinear finite element (FE) model, which accounts for anisotropy, to a state space model describing the SynRM drive system. The simulation results are also validated by comparison to test data of a prototype ALA rotor SynRM drive system.
NASA Astrophysics Data System (ADS)
Akar, Mehmet
2013-01-01
In this study, a new method was presented for the detection of a static eccentricity fault in a closed loop operating induction motor driven by inverter. Contrary to the motors supplied by the line, if the speed and load, and therefore the amplitude and frequency, of the current constantly change then this also causes a continuous change in the location of fault harmonics in the frequency spectrum. Angular Domain Order Tracking analysis (AD-OT) is one of the most frequently used fault diagnosis methods in the monitoring of rotating machines and the analysis of dynamic vibration signals. In the presented experimental study, motor phase current and rotor speed were monitored at various speeds and load levels with a healthy and static eccentricity fault in the closed loop driven induction motor with vector control. The AD-OT method was applied to the motor current and the results were compared with the traditional FFT and Fourier Transform based Order Tracking (FT-OT) methods. The experimental results demonstrate that AD-OT method is more efficient than the FFT and FT-OT methods for fault diagnosis, especially while the motor is operating run-up and run-down. Also the AD-OT does not incur any additional cost for the user because in inverter driven systems, current and speed sensor coexist in the system. The main innovative parts of this study are that AD-OT method was implemented on the motor current signal for the first time.
NASA Astrophysics Data System (ADS)
Gu, F.; Wang, T.; Alwodai, A.; Tian, X.; Shao, Y.; Ball, A. D.
2015-01-01
Motor current signature analysis (MCSA) has been an effective way of monitoring electrical machines for many years. However, inadequate accuracy in diagnosing incipient broken rotor bars (BRB) has motivated many studies into improving this method. In this paper a modulation signal bispectrum (MSB) analysis is applied to motor currents from different broken bar cases and a new MSB based sideband estimator (MSB-SE) and sideband amplitude estimator are introduced for obtaining the amplitude at (1 ± 2 s)fs (s is the rotor slip and fs is the fundamental supply frequency) with high accuracy. As the MSB-SE has a good performance of noise suppression, the new estimator produces more accurate results in predicting the number of BRB, compared with conventional power spectrum analysis. Moreover, the paper has also developed an improved model for motor current signals under rotor fault conditions and an effective method to decouple the BRB current which interferes with that of speed oscillations associated with BRB. These provide theoretical supports for the new estimators and clarify the issues in using conventional bispectrum analysis.
Integrated Cooling System for Induction Motor Traction Drives, CARAT Program Phase Two Final Report
Konrad, Charles E.
2002-12-03
This Program is directed toward improvements in electric vehicle/hybrid electric vehicle traction systems, and in particular, the development of a low cost, highly efficient, compact traction motor-controller system targeted for high volume automotive use. Because of the complex inter-relationships between the motor and the controller, the combination of motor and controller must be considered as a system in the design and evaluation of overall cost and performance. The induction motor is ideally suited for use as a traction motor because of its basic ruggedness, low cost, and high efficiency. As one can see in Figure 1.1, the induction motor traction drive has been continually evolving through a succession of programs spanning the past fifteen years. VPT marketed an induction motor-based traction drive system, the EV2000, which proved to be a reliable, high performance system that was used in a wide range of vehicles. The EV2000 drives evolved from the Modular Electric Vehicle Program (MEVP) and has been used in vehicles ranging in size from 3,000 lb. autos and utility vans, to 32,000 lb. city transit buses. Vehicles powered by the EV2000 induction motor powertrain have accumulated over 2 million miles of service. The EV2000 induction motor system represents 1993 state-of-the-art technology, and evolved from earlier induction motor programs that drove induction motor speeds up to 15,000 rpm to reduce the motor size and cost. It was recognized that the improvements in power density and motor cost sought in the PNGV program could only be achieved through increases in motor speed. Esson’s Rule for motor power clearly states that the power obtainable from a given motor design is the product of motor speed and volume. In order to meet the CARAT Program objectives, the maximum speed goal of the induction motor designed in this Program was increased from 15,000 rpm to 20,000 rpm while maintaining the efficiency and durability demonstrated by lower speed designs done in
Aerospace induction motor actuators driven from a 20-kHz power link
NASA Technical Reports Server (NTRS)
Hansen, Irving G.
1990-01-01
Aerospace electromechanical actuators utilizing induction motors are under development in sizes up to 40 kW. While these actuators have immediate application to the Advanced Launch System (ALS) program, several potential applications are currently under study including the Advanced Aircraft Program. Several recent advances developed for the Space Station Freedom have allowed induction motors to be selected as a first choice for such applications. Among these technologies are bi-directional electronics and high frequency power distribution techniques. Each of these technologies are discussed with emphasis on their impact upon induction motor operation.
Energy-saving technology of vector controlled induction motor based on the adaptive neuro-controller
NASA Astrophysics Data System (ADS)
Engel, E.; Kovalev, I. V.; Karandeev, D.
2015-10-01
The ongoing evolution of the power system towards a Smart Grid implies an important role of intelligent technologies, but poses strict requirements on their control schemes to preserve stability and controllability. This paper presents the adaptive neuro-controller for the vector control of induction motor within Smart Gird. The validity and effectiveness of the proposed energy-saving technology of vector controlled induction motor based on adaptive neuro-controller are verified by simulation results at different operating conditions over a wide speed range of induction motor.
Detection of broken rotor bars in induction machines: An approach using wavelet packets in MCSA
NASA Astrophysics Data System (ADS)
Escobar-Moreira, León; Antonino-Daviu, José; Riera-Guasp, Martin
2012-12-01
Bar breaking diagnosis in electrical induction cage motors is a topic of interest due to their extensive use in industry. In contrast to the typical method of using Fourier analysis of the steady-state stator current, Discrete Wavelet Transform (DWT) methods have been found to better analyze the time changing nature of the current spectrum of these machines at start-up when broken bars exist [1]. This paper advances the analysis to Wavelet Packets (WP) in order to study the high order harmonic components of the spectrum which constitute a useful source of information in situations where tracing the low-frequency fault harmonics (sideband components) may not reach a definite diagnostic (i.e. presence of low-frequency load torque oscillations, effect of inter-bar currents, etc...).
The right {mu}P simplifies using induction motors to propel electric cars
Baum, J.; Berringer, K.
1994-03-31
In electric vehicles (EVs), AC induction motors can provide variable speed at low cost. The most common method for controlling induction motors uses a 3-phase AC voltage-source inverter with sine-wave PWM (pulse width modulation). Because the motor`s speed and acceleration depend on amplitude as well as frequency, the inverter must produce sine waves of variable voltage and frequency. The authors describe how a single microcontroller can provide such control functions while generating PWM waveforms in which the modulation is sinusoidal.
NASA Astrophysics Data System (ADS)
Zhao, J.; Zheng, T. Q.; Zhang, W.; Fang, J.; Liu, Y. M.
2011-11-01
A new type high temperature superconductor linear induction motor is designed and analyzed as a prototype to ensure applicability aimed at industrial motors. Made of Bi-2223/Ag, primary windings are distributed with the double-layer concentrated structure. The motor is analyzed by 2D electromagnetic Finite Element Method to get magnetic field distribution, thrust force, vertical force and so on. The critical current of motor and the electromagnetic force are mostly decided by the leakage flux density of primary slot and by the main magnetic flux and eddy current respectively. The structural parameters of motor have a great influence on the distribution of magnetic field. Under constant currents, the properties of motor are analyzed with different slot widths, slot heights and winding turns. The properties of motor, such as the maximum slot leakage flux density, motor thrust and motor vertical force, are analyzed with different structural parameters.
Modelling and simulation of voltage inverter fed induction motor with stator flux orientation
Rafajlovski, G.; Ratz, E.; Manov, D.; Mircevski, S.
1995-12-31
This paper deals with the application of a non-linear control technique in a three phase inverter-fed induction motor. Also mathematical model for dynamic analysis of an induction motor and voltage controlled inverter in stator coordinate system is described. Digital simulation has been utilized to prove the performance and simplicity of the induction motor mathematical formulation. These models can be easily transformed for freely chosen rotating frame of reference. In this control system of stator flux controlled induction motor the instantaneous values of the flux and torque are calculated from only the primary current variables. By using instantaneous voltage space vectors with selection of optimum inverter switching modes employing vector modulation technique, the direct control of torque and stator flux is achieved.
Optimal efficiency vector control of induction motor drive system for drum washing machine
NASA Astrophysics Data System (ADS)
Lee, Won Cheol; Yu, Jae Sung; Jang, Bong An; Won, Chung Yuen
2005-12-01
In home appliances, electric energy is optimally controlled by using power electronics technology, creating a comfortable environment in terms of energy saving, low sound generation, and reduced time consumption. Usually simplicity and robustness make the three phase induction motor attractive for use in domestic appliance, including washing machines. Two main types of domestic washing machine have evolved. We focus on efficiency of the front loading machine favored in Europe, which has a horizontal drum axis. This paper presents the control algorithm for optimal efficiency drives of an induction motor for drum washing machine. This system uses a simple model of the induction motor that include equations of the iron losses. The proposed optimal efficiency control algorithm calculates commands of the reference torque and flux currents for the flux oriented control of the induction motor. The proposed algorithm is verified through digital simulation.
Jeon, W.J.; Katoh, S.; Iwamoto, T.; Kamiya, Y.; Onuki, T.
1999-09-01
This paper treats a novel linear hybrid motor (LHM) by both induction and synchronous operations. The proposed motor consists of one pair of linear synchronous motors (LSMs) and a linear induction motor (LIM). The primary-cores of both LSM and LIM have a common ring winding, and the secondary solid-conductor is arranged in both LIM and the interpole space of LSM. The feature of the motor is that the undesirable vertical force in LSM is offset by the symmetrical double-sided construction and the secondary is capable of self-starting by induction operation. From the investigation by the three-dimensional finite element analysis and experiment, the authors derive an optimal exciting condition for starting, and then verify that the proposed LHM is effective for practical use.
Use of fuzzy inference system for condition monitoring of induction motor
NASA Astrophysics Data System (ADS)
Janier, Josefina B.; Zaim Zaharia, M. F.; Karim, Samsul Ariffin Abd.
2012-09-01
Three phase induction motors are commonly used in industry due to its robustness, simplicity of its construction and high reliability. The tasks performed by these motors grow increasingly complex because of modern industries hence there is a need to determine the faults. Early detection of faults will reduce an unscheduled machine downtime that can upset production deadlines and may cause heavy financial losses. This paper is focused in developing a computer based system using Fuzzy Inference system's membership function. An unusual increase in vibration of the motor could be an indicator of faulty condition hence the vibration of the motor of an induction motor was used as an input, whereas the output is the motor condition. An inference system of the Fuzzy Logic was created to classify the vibration characteristics of the motor which is called vibration analysis. The system classified the motor of the gas distribution pump condition as from 'acceptable' to 'monitor closely'. The early detection of unusual increase in vibration of the induction motor is an important part of a predictive maintenance for motor driven machinery.
Passive magnetic bearing for a motor-generator
Post, Richard F.
2006-07-18
Conductive lap windings are interleaved with conventional loops in the stator of a motor-generator. The rotor provides magnetic induction lines that, when rotated, cut across the lap windings and the loops. When the rotor is laterally displaced from its equilibrium axis of rotation, its magnetic lines of induction induce a current in the interleaved lap windings. The induced current interacts with the magnetic lines of induction of the rotor in accordance with Lenz's law to generate a radial force that returns the rotor to its equilibrium axis of rotation.
NASA Astrophysics Data System (ADS)
Liu, Chengcheng; Zhu, Jianguo; Wang, Youhua; Guo, Youguang; Lei, Gang; Liu, Xiaojing
2015-05-01
This paper proposes a low-cost double rotor axial flux motor (DRAFM) with low cost soft magnetic composite (SMC) core and ferrite permanent magnets (PMs). The topology and operating principle of DRAFM and design considerations for best use of magnetic materials are presented. A 905 W 4800 rpm DRAFM is designed for replacing the high cost NdFeB permanent magnet synchronous motor (PMSM) in a refrigerator compressor. By using the finite element method, the electromagnetic parameters and performance of the DRAFM operated under the field oriented control scheme are calculated. Through the analysis, it is shown that that the SMC and ferrite PM materials can be good candidates for low-cost electric motor applications.
Baskin, J. M.; Miller, G. E.; Wiesner, W.
1985-12-10
A fixed pitch wind turbine rotor is teeter mounted onto a low speed input shaft which is connected to the input of a step-up transmission. The output of the transmission is connected to a rotary pole amplitude modulated induction machine which is operable as a generator at a plurality of discreet speeds of rotation and is also operable as a startup motor for the rotor. A switch responsive to the rotational speed of the wind turbine rotor switches the generator from one speed of operation to the other. The rotor hub and the inner body portions of two blades which extend radially outwardly in opposite directions from the hub, are constructed from steel. The outer end portions of the blade are constructed from a lighter material, such as wood, and are both thinner and narrower than the remainder of the rotor. The outer end section of each blade includes a main body portion and a trailing edge portion which is hinge-connected to the main body portion. Each blade includes a centrifugal force operated positioning means which normally holds the drag brake section in a retracted position, but operates in response to a predetermined magnitude of centrifugal force to move the drag brake section into its deployed position. Each blade has an airfoil cross section and each blade has a plus twist inner portion adjacent the hub changing to first a zero twist and then a minus twist as it extends radially outwardly from the hub.
Sound based induction motor fault diagnosis using Kohonen self-organizing map
NASA Astrophysics Data System (ADS)
Germen, Emin; Başaran, Murat; Fidan, Mehmet
2014-05-01
The induction motors, which have simple structures and design, are the essential elements of the industry. Their long-lasting utilization in critical processes possibly causes unavoidable mechanical and electrical defects that can deteriorate the production. The early diagnosis of the defects in induction motors is crucial in order to avoid interruption of manufacturing. In this work, the mechanical and the electrical faults which can be observed frequently on the induction motors are classified by means of analysis of the acoustic data of squirrel cage induction motors recorded by using several microphones simultaneously since the true nature of propagation of sound around the running motor provides specific clues about the types of the faults. In order to reveal the traces of the faults, multiple microphones are placed in a hemispherical shape around the motor. Correlation and wavelet-based analyses are applied for extracting necessary features from the recorded data. The features obtained from same types of motors with different kind of faults are used for the classification using the Self-Organizing Maps method. As it is described in this paper, highly motivating results are obtained both on the separation of healthy motor and faulty one and on the classification of fault types.
Chen, J.E.
1995-12-31
This paper describes non-linear models of a 2-phase permanent magnet synchronous motor drive in brushless DC and microstepping modes. The models account for everything from the main power bus up to and including the mechanical load and velocity feedback loop. In particular, the models include the power electronics for each phase complete with their internal feedback loops. Classical state space averaged power electronics models are transformed to the rotor reference frame along with the usual electromechanical variables. Since SPICE linearizes the rotor reference frame model about shaft velocity, instead of shaft angle, frequency domain methods apply. The frequency domain analysis detects unstable interactions between torque angle and deliberate feedback within the drives. Time domain simulations using stator reference frame models confirm the results. All models are SPICE-compatible but were developed on Cadence`s Analog Workbench.
Rotor Losses in a Switched Reluctance Motor - Analysis and Reduction Methods
NASA Astrophysics Data System (ADS)
Schweighofer, B.; Recheis, M.; Fulmek, P.; Wegleiter, H.
2013-01-01
Due to the increasing hybridization and electrification of vehicles, flywheel energy storage devices are an important area of research. In automotive application besides the weight criteria, some additionally constrains, such as size, eﬃciency and especially cost have to be fulfilled. Therefore typically a compact design, in which the rotor of the needed electrical machine simultaneously acts as storage mass is chosen. Since the machine is running in vacuum and the rotor can dissipate its heat only by means of thermal radiation or through the bearings if conventional bearings are used, the rotor losses play a vital role. In this work the rotor losses of a switched reluctance machine are analyzed in detail and a method to reduce the rotor losses is proposed.
NASA Astrophysics Data System (ADS)
Walkhoff, Lutz-Ruediger
1989-12-01
With the utilization of high value magnets with stiff magnetization, it is possible to establish a 3-D, analytic field calculation process in which the influence of the permeability is taken into account. The process is based on the reflection laws for the scalar magnetic potential and allows examination of the influence of the permeability on the profile of the induction in gap. The inductivity of the windings is approximately obtained with the magnetic field of the stator windings, that is found three dimensionally in the winding area. Since the permanent magnet material used is a good electrical conductor, eddy current losses can appear in the magnet with phase currents. For the first losses estimation, the stationary stator field in the magnet area was calculated. The induction in the rotor is relatively low for maximal currents so that only very minimal losses occur. The dissipation was calculated with the Paynting vector from the vector potential.
NASA Astrophysics Data System (ADS)
Cai, Jun; Deng, Zhiquan
2015-02-01
Accurate rotor position signal is highly required for controlling the switched reluctance motor (SRM). The use of galvanic isolated sensing coils can provide independent circuit for position estimation without affecting the SRM actuation. However, the cross-coupling between main winding and sensing coil, and the mutual coupling between adjacent phase sensing coils may affect the position estimation performance seriously. In this paper, three sensing coil configurations in a 12/8 structure SRM are analyzed and compared for selecting an optimal configuration that can effectively minimize the bad effects of the cross-coupling factors. The finite element analysis and experimental results are provided for verification.
Cai, Jun; Deng, Zhiquan
2015-02-01
Accurate rotor position signal is highly required for controlling the switched reluctance motor (SRM). The use of galvanic isolated sensing coils can provide independent circuit for position estimation without affecting the SRM actuation. However, the cross-coupling between main winding and sensing coil, and the mutual coupling between adjacent phase sensing coils may affect the position estimation performance seriously. In this paper, three sensing coil configurations in a 12/8 structure SRM are analyzed and compared for selecting an optimal configuration that can effectively minimize the bad effects of the cross-coupling factors. The finite element analysis and experimental results are provided for verification. PMID:25725876
EFFICIENCY OPTIMIZATION CONTROL OF AC INDUCTION MOTORS: INITIAL LABORATORY RESULTS
The report discusses the development of a fuzzy logic, energy-optimizing controller to improve the efficiency of motor/drive combinations that operate at varying loads and speeds. his energy optimizer is complemented by a sensorless speed controller that maintains motor shaft rev...
EFFICIENCY OPTIMIZATIN CONTROL OF AC INDUCTION MOTORS: INITIAL LABORATORY RESULTS
The report discusses the development of a fuzzy logic, energy-optimizing controller to improve the efficiency of motor/drive combinations that operate at varying loads and speeds. This energy optimizer is complemented by a sensorless speed controller that maintains motor shaft re...
Thermal and vibration dynamic analysis of an induction motor using optical fiber Bragg gratings
NASA Astrophysics Data System (ADS)
Sousa, Kleiton d. M.; Dreyer, Uilian J.; Martelli, Cicero; Cardozo da Silva, Jean Carlos
2015-09-01
In this paper it is presented the results of temperature and vibration measurements in a Three-phase Induction Motor (TIM) running at no-load condition. Vibration and temperature analysis are the most successful techniques used for condition monitoring of induction motors. The vibration is measured using two FBGs installed inside of the motor between two subsequent stator teeth. The motor spectrum of vibration when power is at 60 Hz presents the frequencies 60 Hz, 120 Hz, 180 Hz, and 240 Hz as theoretically expected. For the temperature measurement two FBGs are encapsulated in an alumina tube fixed along the stator. The results show 0.9°C difference between the two FBG caused by the motor ventilation nearer of one FBG. These measurements can be used to determine TIM parameters and still be predictive maintenance tool.
NASA Astrophysics Data System (ADS)
Mosallanejad, Ali; Shoulaie, Abbas
2011-07-01
This paper reports a study of coil inductance profile in all positions of plunger in tubular linear reluctance motors (TLRMs) with open type magnetic circuits. In this paper, maximum inductance calculation methods in winding of tubular linear reluctance motors are described based on energy method. Furthermore, in order to calculate the maximum inductance, equivalent permeability is measured. Electromagnetic finite-element analysis for simulation and calculation of coil inductance in this motor is used. Simulation results of coil inductance calculation using 3-D FEM with coil current excitation is compared to theoretical and experimental results. The comparison yields a good agreement.
Research on Direct Torque Control of Induction Motor Based on TMS320LF2407A
NASA Astrophysics Data System (ADS)
Lufei, Xu; Guangqun, Nan
The direct torque control of Induction Motor is one of the high performance control system, which was proposed after the vector control scheme. During the recent 20 years, It has been developed rapidly for its concise system scheme, excellent dynamic and static performances. DTC system directly controls the electromagnetic torque and stator flux, using the analyzing method of space vector and stator flux orientation. This paper establishes the mathematical model of direct torque control (DTC) system of induction motor, and direct torque control (DTC) scheme of induction motor based on TMS320LF2407A is introduced. The control scheme gets the switch control signal of inverter with the space voltage vector modulation technology. Finally the approach has been implemented on DSP in a 1.1 kW drive. The results show that the DTC with SVPWM has many merits such as simple realization, good running performance and high voltage utilization ratio.
Simple and Robust Indirect Thrust Control for Positioning of Linear Induction Motors
NASA Astrophysics Data System (ADS)
Martínez-Iturralde, Miguel; Martínez, Gonzalo; Castelli, Marcelo; Rico, Andrés García; Flórez, Julián
Dealing with position control of Linear Induction Motors (LIM), most strategies in bibliography are based on Secondary Flux Oriented Control (SFOC) and Direct Thrust Control (DTC). However, SFOC of linear induction motors needs complex identification methods to compensate parameter variation during operation, mainly due to local heating and end-effects. On the other hand, DTC based methods for LIMs present thrust ripple and have problems at low and zero speeds. In this paper, a new Indirect Thrust Control (ITC) based strategy for position control of linear induction motors that makes up for these drawbacks is presented. The position control loop design methodology and the method for automatic adjustment of compensators are described. Experimental results are presented to evaluate the performance and sensitivity of the control strategy. Finally, some conclusions are drawn about the applicability of the new algorithm that demonstrate the main advantages versus SFOC and DTC.
Implementation of DSP Based Cost Effective Inverter Fed Induction Motor Drive with VisSim
NASA Astrophysics Data System (ADS)
Mohanty, Nalin K.; Muthu, Ranganath
2012-03-01
The implementation of a Digital Signal Processor (DSP) based high-performance cost effective fed Induction Motor drive with VisSim/Embedded Controls Developer (ECD) is presented in this paper. In the experimental work VisSim/ECD software automatically converts the in built block diagram to C code and compiles, links, and downloads the code to DSP processor TMS320F2812. The DSP processor generates the required PWM to a cost effective
Evaluation of half wave induction motor drive for use in passenger vehicles
NASA Technical Reports Server (NTRS)
Hoft, R. G.; Kawamura, A.; Goodarzi, A.; Yang, G. Q.; Erickson, C. L.
1985-01-01
Research performed at the University of Missouri-Columbia to devise and design a lower cost inverter induction motor drive for electrical propulsion of passenger vehicles is described. A two phase inverter motor system is recommended. The new design is predicted to provide comparable vehicle performance, improved reliability and a cost advantage for a high production vehicle, decreased total rating of the power semiconductor switches, and a somewhat simpler control hardware compared to the conventional three phase bridge inverter motor drive system. The major disadvantages of the two phase inverter motor drive are that it is larger and more expensive than a three phase machine, the design of snubbers for the power leakage inductances produce higher transient voltages, and the torque pulsations are relatively large because of the necessity to limit the inverter switching frequency to achieve high efficiency.
Heat transfer enhancement in the unfinned frame of an externally cooled induction motor
Jeon, C.S.; Yoon, M.K.; Kauh, S.K.
2000-02-01
This article describes an experimental investigation to study the effect of guide vanes on the heat transfer coefficient over the unfinned frame of an externally cooled induction motor. Guide vanes with various heights and spacings have been tested. In general, the guide vanes modify the air flow over the frame, hence increasing the heat transfer coefficient. An optimum heat transfer case is found, for which the average heat transfer coefficient is 70% higher than for the case without guide vanes. The velocity distributions of the air flow are measured for comparison with the heat transfer coefficient fields. The location of the terminal box is optimized, resulting in a 1 C drop in the average temperature rise of the coil motor. Finally, the results of this research are applied to a real induction motor and its average coil temperature becomes 9 C lower than that of a commercial motor.
Constant slip control of induction motor at light load
Feng Xiaogang; Chen Boshi
1996-12-31
The most widely used AC motor drives adopt Rated Flux Control (RFC) method. However, at light load condition, RFC causes excessive iron loss, thus the conversion efficiency of the drive system impaired. This paper introduces a new control approach--Constant Slip Control (CSC), which minimize the stator current at light load, so that the iron loss and reactive power consumption of the motor are decreased. Simulation results compare the power consumption of CSC with that of RFC in order to validate the theoretical development. In the last part, realization of CSC is discussed.
NASA Astrophysics Data System (ADS)
Cabal-Yepez, E.; Valtierra-Rodriguez, M.; Romero-Troncoso, R. J.; Garcia-Perez, A.; Osornio-Rios, R. A.; Miranda-Vidales, H.; Alvarez-Salas, R.
2012-07-01
For industry, a faulty induction motor signifies production reduction and cost increase. Real-world induction motors can have one or more faults present at the same time that can mislead to a wrong decision about its operational condition. The detection of multiple combined faults is a demanding task, difficult to accomplish even with computing intensive techniques. This work introduces information entropy and artificial neural networks for detecting multiple combined faults by analyzing the 3-axis startup vibration signals of the rotating machine. A field programmable gate array implementation is developed for automatic online detection of single and combined faults in real time.
A high-speed induction motor making use of the third harmonic of the magnetic flux
NASA Astrophysics Data System (ADS)
Goleman, Ryszard
1994-05-01
This paper indicates some possibilities of construction of high-speed induction motors taking advantage of the magnetic flux third harmonic due to a process of magnetization of nonlinear magnetic circuits. Configurations of magnetic frequency triplers, which can be used as basic stator structures and generate a distorted flux, are presented. The paper also describes an experimental high-speed induction motor supplied from a single-phase source via a magnetic frequency tripler that make possible to obtain a rotating field having a synchronous speed equal to 9000 rpm at a supply voltage angular frequency of 314 rd.
Variable-Speed Induction Motor Drives for Aircraft Environmental Control Compressors
NASA Technical Reports Server (NTRS)
Mildice, J. W.; Hansen, I. G.; Schreiner, K. E.; Roth, M. E.
1996-01-01
New, more-efficient designs for aircraft jet engines are not capable of supplying the large quantities of bleed air necessary to provide pressurization and air conditioning for the environmental control systems (ECS) of the next generation of large passenger aircraft. System analysis and engineering have determined that electrically-driven ECS can help to maintain the improved fuel efficiencies; and electronic controllers and induction motors are now being developed in a NASA/NPD SBIR Program to drive both types of ECS compressors. Previous variable-speed induction motor/controller system developments and publications have primarily focused on field-oriented control, with large transient reserve power, for maximum acceleration and optimum response in actuator and robotics systems. The application area addressed herein is characterized by slowly-changing inputs and outputs, small reserve power capability for acceleration, and optimization for maximum efficiency. This paper therefore focuses on the differences between this case and the optimum response case, and shows the development of this new motor/controller approach. It starts with the creation of a new set of controller requirements. In response to those requirements, new control algorithms are being developed and implemented in an embedded computer, which is integrated into the motor controller closed loop. Buffered logic outputs are used to drive the power switches in a resonant-technology, power processor/motor-controller, at switching/resonant frequencies high enough to support efficient high-frequency induction motor operation at speeds up to 50,000-RPA
Methods of torque ripple reduction for flux reversal motor
NASA Astrophysics Data System (ADS)
Vakil, Gaurang; Sheth, N. K.; Miller, David
2009-04-01
This paper presents two-dimensional finite element based results for various methods of torque ripple reduction in flux-reversal motors. The effects of variation in magnet and rotor pole heights, rotor pole skewing, and multiple teeth per rotor pole on the cogging torque, developed torque, torque ripple, and phase inductance and also an optimum value of the magnet and rotor pole heights, skew angle, and choice of teeth per rotor pole with the teeth depth resulting in torque ripple reduction are presented.
Dual-circuit segmented rail phased induction motor
Marder, Barry M.; Cowan, Jr., Maynard
2002-01-01
An improved linear motor utilizes two circuits, rather that one circuit and an opposed plate, to gain efficiency. The powered circuit is a flat conductive coil. The opposed segmented rail circuit is either a plurality of similar conductive coils that are shorted, or a plurality of ladders formed of opposed conductive bars connected by a plurality of spaced conductors. In each embodiment, the conductors are preferably cables formed from a plurality of intertwined insulated wires to carry current evenly.
NASA Astrophysics Data System (ADS)
Kang, Myeongsu; Kim, Jong-Myon
2013-12-01
This paper proposes singular value decomposition (SVD)-based feature extraction methods for fault classification of an induction motor: a short-time energy (STE) plus SVD technique in the time-domain analysis, and a discrete cosine transform (DCT) plus SVD technique in the frequency-domain analysis. To early identify induction motor faults, the extracted features are utilized as the inputs of multi-layer support vector machines (MLSVMs). Since SVMs perform well with the radial basis function (RBF) kernel for appropriately categorizing the faults of the induction motor, it is important to explore the impact of the σ values for the RBF kernel, which affects the classification accuracy. Likewise, this paper quantitatively evaluates the classification accuracy with different numbers of features, because the number of features affects the classification accuracy. According to the experimental results, although SVD-based features are effective for a noiseless environment, the STE plus SVD feature extraction approach is more effective with and without sensor noise in terms of the classification accuracy than the DCT plus SVD feature extraction approach. To demonstrate the improved classification of the proposed approach for identifying faults of the induction motor, the proposed SVD based feature extraction approach is compared with other state-of-the art methods and yields higher classification accuracies for both noiseless and noisy environments than conventional approaches.
Fuzzy Logic Controlled Solar Module for Driving Three- Phase Induction Motor
NASA Astrophysics Data System (ADS)
Afiqah Zainal, Nurul; Sooi Tat, Chan; Ajisman
2016-02-01
Renewable energy produced by solar module gives advantages for generated three- phase induction motor in remote area. But, solar module's ou tput is uncertain and complex. Fuzzy logic controller is one of controllers that can handle non-linear system and maximum power of solar module. Fuzzy logic controller used for Maximum Power Point Tracking (MPPT) technique to control Pulse-Width Modulation (PWM) for switching power electronics circuit. DC-DC boost converter used to boost up photovoltaic voltage to desired output and supply voltage source inverter which controlled by three-phase PWM generated by microcontroller. IGBT switched Voltage source inverter (VSI) produced alternating current (AC) voltage from direct current (DC) source to control speed of three-phase induction motor from boost converter output. Results showed that, the output power of solar module is optimized and controlled by using fuzzy logic controller. Besides that, the three-phase induction motor can be drive and control using VSI switching by the PWM signal generated by the fuzzy logic controller. This concluded that the non-linear system can be controlled and used in driving three-phase induction motor.
Smart Sensor for Online Detection of Multiple-Combined Faults in VSD-Fed Induction Motors
Garcia-Ramirez, Armando G.; Osornio-Rios, Roque A.; Granados-Lieberman, David; Garcia-Perez, Arturo; Romero-Troncoso, Rene J.
2012-01-01
Induction motors fed through variable speed drives (VSD) are widely used in different industrial processes. Nowadays, the industry demands the integration of smart sensors to improve the fault detection in order to reduce cost, maintenance and power consumption. Induction motors can develop one or more faults at the same time that can be produce severe damages. The combined fault identification in induction motors is a demanding task, but it has been rarely considered in spite of being a common situation, because it is difficult to identify two or more faults simultaneously. This work presents a smart sensor for online detection of simple and multiple-combined faults in induction motors fed through a VSD in a wide frequency range covering low frequencies from 3 Hz and high frequencies up to 60 Hz based on a primary sensor being a commercially available current clamp or a hall-effect sensor. The proposed smart sensor implements a methodology based on the fast Fourier transform (FFT), RMS calculation and artificial neural networks (ANN), which are processed online using digital hardware signal processing based on field programmable gate array (FPGA).
Wächter, André; Bi, Yumin; Dunn, Stanley D.; Cain, Brian D.; Sielaff, Hendrik; Wintermann, Frank; Engelbrecht, Siegfried; Junge, Wolfgang
2011-01-01
ATP is synthesized by ATP synthase (FOF1-ATPase). Its rotary electromotor (FO) translocates protons (in some organisms sodium cations) and generates torque to drive the rotary chemical generator (F1). Elastic power transmission between FO and F1 is essential for smoothing the cooperation of these stepping motors, thereby increasing their kinetic efficiency. A particularly compliant elastic domain is located on the central rotor (c10–15/ϵ/γ), right between the two sites of torque generation and consumption. The hinge on the active lever on subunit β adds further compliance. It is under contention whether or not the peripheral stalk (and the “stator” as a whole) also serves as elastic buffer. In the enzyme from Escherichia coli, the most extended component of the stalk is the homodimer b2, a right-handed α-helical coiled coil. By fluctuation analysis we determined the spring constant of the stator in response to twisting and bending, and compared wild-type with b-mutant enzymes. In both deformation modes, the stator was very stiff in the wild type. It was more compliant if b was elongated by 11 amino acid residues. Substitution of three consecutive residues in b by glycine, expected to destabilize its α-helical structure, further reduced the stiffness against bending deformation. In any case, the stator was at least 10-fold stiffer than the rotor, and the enzyme retained its proton-coupled activity. PMID:21368147
Wächter, André; Bi, Yumin; Dunn, Stanley D; Cain, Brian D; Sielaff, Hendrik; Wintermann, Frank; Engelbrecht, Siegfried; Junge, Wolfgang
2011-03-01
ATP is synthesized by ATP synthase (F(O)F(1)-ATPase). Its rotary electromotor (F(O)) translocates protons (in some organisms sodium cations) and generates torque to drive the rotary chemical generator (F(1)). Elastic power transmission between F(O) and F(1) is essential for smoothing the cooperation of these stepping motors, thereby increasing their kinetic efficiency. A particularly compliant elastic domain is located on the central rotor (c(10-15)/ε/γ), right between the two sites of torque generation and consumption. The hinge on the active lever on subunit β adds further compliance. It is under contention whether or not the peripheral stalk (and the "stator" as a whole) also serves as elastic buffer. In the enzyme from Escherichia coli, the most extended component of the stalk is the homodimer b(2), a right-handed α-helical coiled coil. By fluctuation analysis we determined the spring constant of the stator in response to twisting and bending, and compared wild-type with b-mutant enzymes. In both deformation modes, the stator was very stiff in the wild type. It was more compliant if b was elongated by 11 amino acid residues. Substitution of three consecutive residues in b by glycine, expected to destabilize its α-helical structure, further reduced the stiffness against bending deformation. In any case, the stator was at least 10-fold stiffer than the rotor, and the enzyme retained its proton-coupled activity. PMID:21368147
NASA Astrophysics Data System (ADS)
Tutelea, L. N.; Deaconu, S. I.; Boldea, I.; Popa, G. N.
2014-03-01
The actual e - continuously variable transmission (e-CVT) solution for the parallel Hybrid Electric Vehicle (HEV) requires two electric machines, two inverters, and a planetary gear. A distinct electric generator and a propulsion electric motor, both with full power converters, are typical for a series HEV. In an effort to simplify the planetary-geared e-CVT for the parallel HEV or the series HEV we hereby propose to replace the basically two electric machines and their two power converters by a single, axial-air-gap, electric machine central stator, fed from a single PWM converter with dual frequency voltage output and two independent PM rotors, destined for hybrid electric vehicles (HEV) and military vehicles applications. The proposed topologies and the magneto-motive force analysis are the core of the paper.
An innovative direct self-control scheme for induction motor drives
Bonanno, F.; Consoli, A.; Raciti, A.; Testa, A.
1997-09-01
The paper presents a new direct self-control (DSC) scheme for induction motor drives using the stator voltage third harmonic component in order to estimate the air-gap flux and the torque as well as to synchronize the supply voltage vector. Compared to previous DSC schemes the new one is independent from any motor parameter variation, specifically on stator resistance thus showing better performances at low speeds. The paper starts with a quick review on standard DSC main features pointing out the influence of stator resistance variations on the flux and torque control. The new DSC scheme is then introduced and evaluated by simulations and experimental tests on a 1.5-kW induction motor drive.
A Fast Induction Motor Speed Estimation based on Hybrid Particle Swarm Optimization (HPSO)
NASA Astrophysics Data System (ADS)
Aryza, Solly; Abdallah, Ahmed N.; Khalidin, Zulkeflee bin; Lubis, Zulkarnain; Jie, Ma
Intelligent control and estimation of power electronic systems by fuzzy logic and neural network techniques with fast torque and flux show tremendous promise in future. This paper proposed the application of Hybrid Particle Swarm Optimization (HPSO) for losses and operating cost minimization control in the induction motor drives. The main advantages of the proposed technique are; its simple structure and its straightforward maximization of induction motor efficiency and its operating cost for a given load torque. As will be demonstrated, Hybrid Particle Swarm Optimization (HPSO) is so efficient in finding the optimum operating machine's flux level. The results demonstrate the good quality and robustness in the system dynamic response and reduction in the steady-state and transient motor ripple torque.
Modeling and Simulating of Single Side Short Stator Linear Induction Motor with the End Effect
NASA Astrophysics Data System (ADS)
Hamzehbahmani, Hamed
2011-09-01
Linear induction motors are under development for a variety of demanding applications including high speed ground transportation and specific industrial applications. These applications require machines that can produce large forces, operate at high speeds, and can be controlled precisely to meet performance requirements. The design and implementation of these systems require fast and accurate techniques for performing system simulation and control system design. In this paper, a mathematical model for a single side short stator linear induction motor with a consideration of the end effects is presented; and to study the dynamic performance of this linear motor, MATLAB/SIMULINK based simulations are carried out, and finally, the experimental results are compared to simulation results.
NASA Astrophysics Data System (ADS)
Eftekhari, M.; Moallem, M.; Sadri, S.; Hsieh, Min-Fu
2013-11-01
In this paper, a novel online and non-destructive algorithm is proposed to detect inter-turn short circuit faults in the stator windings of an induction motor. This fault detection algorithm is based on the features extracted from infrared images taken from the hottest region of the motor surface. Feature extraction method from infrared thermal images has been developed based on histogram of temperature profile, correlation between fault severity and the hottest region on the motor body, and comparison with healthy motor features. Experiments are conducted to demonstrate the effectiveness of the proposed method using a 2-hp induction motor.
NASA Astrophysics Data System (ADS)
Fang, J.; Sheng, L.; Li, D.; Zhao, J.; Li, Sh.; Qin, W.; Fan, Y.; Zheng, Q. L.; Zhang, W.
A novel High Temperature Superconductor Linear Induction Motor (HTS LIM) is researched in this paper. Since the critical current and the electromagnetic force of the motor are determined mainly by the primary slot leakage flux, the main magnetic flux and eddy current respectively, in order to research the influence of structural parameters and operating parameters on electromagnetic properties of HTS LIM, the motor was analyzed by 2D transient Finite Element Method (FEM). The properties of the motor, such as the maximum slot leakage flux density, motor thrust, motor vertical force and critical current are analyzed with different structural parameters and operating parameters. In addition, an experimental investigation was carried out on prototype HTS motor. Electrical parameters were deduced from these tests and also compared with the analysis results from FEM. AC losses of one HTS coil in the motor were measured and AC losses of all HTS coils in HTS LIM were estimated. The results in this paper could provide reference for the design and research on the HTS LIM.
A current-source inverter fed induction motor drive system with reduced losses
Espinoza, J.R.; Joos, G.
1995-12-31
Standard low and medium induction power motor drives are based on the PWM voltage source inverter (VSI) fed from a diode rectifier. The dual topology, based on the current source inverter/rectifier structure is used in medium and high power applications. This paper addresses some of the drawbacks of this approach compared to the voltage source approach. The proposed drive features: (a) an on-line operated PWM inverter, using instantaneous output capacitor voltage control based on space vector modulation; (b) a line-synchronized PWM rectifier, with dc bus current control; (c) an additional inverter modulation index control loop, ensuring a constant inverter modulation index. The resulting advantages include: (a) ruggedness and inherent continuous regeneration capability; (b) near unity global input power factor; (c) reduced motor voltage distortion; (d) reduced dc bus inductor and switch conduction losses; (e) fast motor dynamic response; (f) elimination of motor circuit resonances. Simulated and experimental results based on a DSP implementation are given.
Inductance Calculation and New Modeling of a Synchronous Reluctance Motor Using Flux Linkages
NASA Astrophysics Data System (ADS)
Nashiki, Masayuki; Inoue, Yoshimitu; Kawai, Youichi; Okuma, Shigeru
New modeling of a synchronous reluctance motor SynRM which has non-linear magnetic characteristics is proposed. And a control method of the SynRM using the new model is developed. The new model is based on the inductance data table or the flux linkage data table which is calculated with the flux linkages of the SynRM at each current (id, iq). Detailed calculation method of the inductances is described. The calculated torque TA with the inductance data table is compared with the torque Tfem which is calculated by FEM and the difference is less than 5% at the rated torque. Therefore the accuracy of the new model is certified. And the same method is applicable to an interior permanent magnet synchronous motor IPMSM. The high performance motor control is realized. The exact current commands (id, iq), the exact voltage feed-forward commands (FFd, FFq) and the adaptive current loop gain (Gd, Gq) are obtained using the FEM data of the motor.
Vuckovic, V.; Vukosavic, S. )
1992-01-01
This paper brings out a control algorithm for VSI fed induction motor drives based on the converter DC link current feedback. It is shown that the speed and flux can be controlled over the wide speed and load range quite satisfactorily for simpler drives. The base commands of both the inverter voltage and frequency are proportional to the reference speed, but each of them is further modified by the signals derived from the DC current sensor. The algorithm is based on the equations well known from the vector control theory, and is aimed to obtain the constant rotor flux and proportionality between the electrical torque, the slip frequency and the active component of the stator current. In this way, the problems of slip compensation, Ri compensation and correction of U/f characteristics are solved in the same time. Analytical considerations and computer simulations of the proposed control structure are in close agreement with the experimental results measured on a prototype drive.
Stator and Rotor Flux Based Deadbeat Direct Torque Control of Induction Machines
NASA Technical Reports Server (NTRS)
Kenny, Barbara H.; Lorenz, Robert D.
2001-01-01
A new, deadbeat type of direct torque control is proposed, analyzed, and experimentally verified in this paper. The control is based on stator and rotor flux as state variables. This choice of state variables allows a graphical representation which is transparent and insightful. The graphical solution shows the effects of realistic considerations such as voltage and current limits. A position and speed sensorless implementation of the control, based on the self-sensing signal injection technique, is also demonstrated experimentally for low speed operation. The paper first develops the new, deadbeat DTC methodology and graphical representation of the new algorithm. It then evaluates feasibility via simulation and experimentally demonstrates performance of the new method with a laboratory prototype including the sensorless methods.
Stator and Rotor Flux Based Deadbeat Direct Torque Control of Induction Machines. Revision 1
NASA Technical Reports Server (NTRS)
Kenny, Barbara H.; Lorenz, Robert D.
2002-01-01
A new, deadbeat type of direct torque control is proposed, analyzed, and experimentally verified in this paper. The control is based on stator and rotor flux as state variables. This choice of state variables allows a graphical representation which is transparent and insightful. The graphical solution shows the effects of realistic considerations such as voltage and current limits. A position and speed sensorless implementation of the control, based on the self-sensing signal injection technique, is also demonstrated experimentally for low speed operation. The paper first develops the new, deadbeat DTC methodology and graphical representation of the new algorithm. It then evaluates feasibility via simulation and experimentally demonstrates performance of the new method with a laboratory prototype including the sensorless methods.
Stator and Rotor Flux Based Deadbeat Direct Torque Control of Induction Machines
NASA Technical Reports Server (NTRS)
Kenny, Barbara H.; Lorenz, Robert D.
2003-01-01
A new, deadbeat type of direct torque control is proposed, analyzed and experimentally verified in this paper. The control is based on stator and rotor flux as state variables. This choice of state variables allows a graphical representation which is transparent and insightful. The graphical solution shows the effects of realistic considerations such as voltage and current limits. A position and speed sensorless implementation of the control, based on the self-sensing signal injection technique, is also demonstrated experimentally for low speed operation. The paper first develops the new, deadbeat DTC methodology and graphical representation of the new algorithm. It then evaluates feasibility via simulation and experimentally demonstrates performance of the new method with a laboratory prototype including the sensorless methods.
Evaluation of induction motor performance using an electronic power factor controller
NASA Technical Reports Server (NTRS)
1978-01-01
The concept of reducing the losses in an induction motor by electronically controlling the time interval between the zero crossing of the applied voltage and the zero crossing of the armature current was evaluated. The effect on power losses and power factor of reducing the applied sinusoidal voltages below the rated value was investigated experimentally. The reduction in power losses was measured using an electronic controller designed and built at MSFC. Modifications to the MSFC controller are described as well as a manually controlled electronic device which does not require that the motor be wye connected and the neutral available. Possible energy savings are examined.
Flywheel induction motor-generator for magnet power supply in small fusion device
NASA Astrophysics Data System (ADS)
Hatakeyma, S.; Yoshino, F.; Tsutsui, H.; Tsuji-Iio, S.
2016-04-01
A flywheel motor-generator (MG) for the toroidal field (TF) coils of a small fusion device was developed which utilizes a commercially available squirrel-cage induction motor. Advantages of the MG are comparably-long duration, quick power response, and easy implementation of power control compared with conventional capacitor-type power supply. A 55-kW MG was fabricated, and TF coils of a small fusion device were energized. The duration of the current flat-top was extended to 1 s which is much longer than those of conventional small devices (around 10-100 ms).
Flywheel induction motor-generator for magnet power supply in small fusion device.
Hatakeyma, S; Yoshino, F; Tsutsui, H; Tsuji-Iio, S
2016-04-01
A flywheel motor-generator (MG) for the toroidal field (TF) coils of a small fusion device was developed which utilizes a commercially available squirrel-cage induction motor. Advantages of the MG are comparably-long duration, quick power response, and easy implementation of power control compared with conventional capacitor-type power supply. A 55-kW MG was fabricated, and TF coils of a small fusion device were energized. The duration of the current flat-top was extended to 1 s which is much longer than those of conventional small devices (around 10-100 ms). PMID:27131676
NASA Astrophysics Data System (ADS)
Kato, Shuhei; Takaku, Taku; Sumitani, Hideo; Shimada, Ryuichi
Flywheel energy storage systems are focused as uninterruptible power supplies (UPS) from the viewpoint of environmental friendliness and high durability performance. Using a low-speed and heavy flywheel, and a low-cost squirrel-cage induction motor/generator, two applications are proposed; 1) 11kW voltage sag compensator using a capacitor self-excited induction generator without semiconductor converters; 2) UPS composed of the flywheel system and an engine generator. From some experimental results, an ideal voltage sag compensator and UPS are realized by the low-technology flywheel system.
Hussey, John H.; Rose, John Scott; Meystrik, Jeffrey J.; White, Kent Lee
2001-01-23
A laminated rotor for an induction motor has a plurality of ferro-magnetic laminations mounted axially on a rotor shaft. Each of the plurality of laminations has a central aperture in the shape of a polygon with sides of equal length. The laminations are alternatingly rotated 180.degree. from one another so that the straight sides of the polygon shaped apertures are misaligned. As a circular rotor shaft is press fit into a stack of laminations, the point of maximum interference occurs at the midpoints of the sides of the polygon (i.e., at the smallest radius of the central apertures of the laminations). Because the laminates are alternatingly rotated, the laminate material at the points of maximum interference yields relatively easily into the vertices (i.e., the greatest radius of the central aperture) of the polygonal central aperture of the next lamination as the shaft is inserted into the stack of laminations. Because of this yielding process, the amount of force required to insert the shaft is reduced, and a tighter fit is achieved.
Tuning the stator resistance of induction motors using artificial neural network
Cabrera, L.A.; Elbuluk, M.E.; Husain, I.
1997-09-01
Tuning the stator resistance of induction motors is very important, especially when it is used to implement direct torque control (DTC) in which the stator resistance is a main parameter. In this paper, an artificial network (ANN) is used to accomplish tuning of the stator resistance of an induction motor. The parallel recursive prediction error and backpropagation training algorithms were used in training the neural network for the simulation and experimental results, respectively. The neural network used to tune the stator resistance was trained on-line, making the DTC strategy more robust and accurate. Simulation results are presented for three different neural-network configurations showing the efficiency of the tuning process. Experimental results were obtained for the one of the three neural-network configuration. Both simulation and experimental results showed that the ANN have tuned the stator resistance in the controller to track actual resistance of the machine.
Induction motor fault diagnosis based on the k-NN and optimal feature selection
NASA Astrophysics Data System (ADS)
Nguyen, Ngoc-Tu; Lee, Hong-Hee
2010-09-01
The k-nearest neighbour (k-NN) rule is applied to diagnose the conditions of induction motors. The features are extracted from the time vibration signals while the optimal features are selected by a genetic algorithm based on a distance criterion. A weight value is assigned to each feature to help select the best quality features. To improve the classification performance of the k-NN rule, each of the k neighbours are evaluated by a weight factor based on the distance to the test pattern. The proposed k-NN is compared to the conventional k-NN and support vector machine classification to verify the performance of an induction motor fault diagnosis.
A novel sliding-mode control of induction motor using space vector modulation technique.
Fu, Tian-Jun; Xie, Wen-Fang
2005-10-01
This paper presents a novel sliding-mode control method for torque control of induction motors. The control principle is based on sliding-mode control combined with space vector modulation technique. The sliding-mode control contributes to the robustness of induction motor drives, and the space vector modulation improves the torque, flux, and current steady-state performance by reducing the ripple. The Lyapunov direct method is used to ensure the reaching and sustaining of sliding mode and stability of the control system. The performance of the proposed system is compared with those of conventional sliding-mode controller and classical PI controller. Finally, computer simulation results show that the proposed control scheme provides robust dynamic characteristics with low torque ripple. PMID:16294775
A combined lift and propulsion system of a steel plate by transverse flux linear induction motors
Hayashiya, H.; Ohsaki, H.; Masada, E.
1999-09-01
To realize a non-contacting conveyance of a steel plate, a combined lift and propulsion system of a steel plate by transverse flux linear induction motors (LIMs) is proposed. By introducing the DC biased AC feeding to the LIM< a steel plate is supported stably and efficiently. In this paper, after showing the advantages of the system, the magnetic levitation experiments are carried out to investigate the feasibility of the system.