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Sample records for pwm speed controller

  1. Performance of High-Speed PWM Control Chips at Cryogenic Temperatures

    NASA Technical Reports Server (NTRS)

    Elbuluk, Malik E.; Gerber, Scott; Hammoud, Ahmad; Patterson, Richard; Overton, Eric

    2001-01-01

    The operation of power electronic systems at cryogenic temperatures is anticipated in many NASA space missions such as planetary exploration and deep space probes. In addition to surviving the space hostile environment, electronics capable of low temperature operation would contribute to improving circuit performance, increasing system efficiency, and reducing development and launch costs. As part of the NASA Glenn Low Temperature Electronics Program, several commercial high-speed Pulse Width Modulation (PWM) chips have been characterized in terms of their performance as a function of temperature in the range of 25 to -196 C (liquid nitrogen). These chips ranged in their electrical characteristics, modes of control, packaging options, and applications. The experimental procedures along with the experimental data obtained on the investigated chips are presented and discussed.

  2. Discrete/PWM Ballast-Resistor Controller

    NASA Technical Reports Server (NTRS)

    King, Roger J.

    1994-01-01

    Circuit offers low switching loss and automatic compensation for failure of ballast resistor. Discrete/PWM ballast-resistor controller improved shunt voltage-regulator circuit designed to supply power from high-resistance source to low-impedance bus. Provides both coarse discrete voltage levels (by switching of ballast resistors) and continuous fine control of voltage via pulse-width modulation.

  3. Robust Design of Motor PWM Control using Modeling and Simulation

    NASA Astrophysics Data System (ADS)

    Zhan, Wei

    A robust design method is developed for Pulse Width Modulation (PWM) motor speed control. A first principle model for DC permanent magnetic motor is used to build a Simulink model for simulation and analysis. Based on the simulation result, the main factors that contributed to the average speed variation are identified using Design of Experiment (DOE). A robust solution is derived to reduce the aver age speed control variation using Response Surface Method (RSM). The robustness of the new design is verified using the simulation model.

  4. PWM control techniques for rectifier filter minimization

    SciTech Connect

    Ziogas, P.D.; Kang, Y-G; Stefanovic, V.R.

    1985-09-01

    Minimization of input/output filters is an essential step towards manufacturing compact low-cost static power supplies. Three PWM control techniques that yield substantial filter size reduction for three-phase (self-commutated) rectifiers are presented and analyzed. Filters required by typical line-commutated rectifiers are used as the basis for comparison. Moreover, it is shown that in addition to filter minimization two of the proposed three control techniques improve substantially the rectifier total input power factor.

  5. PLL/PID Motor Control System by Using Time-Domain Differential Operation of PWM Signal

    NASA Astrophysics Data System (ADS)

    Machida, Hidekazu; Kobayashi, Fuminori

    In PLL motor speed control systems, PID-type loop filter can improve disturbance sensitivity. In this short-paper, we show that, an existing PI-type PLL/PWM motor speed controller can be supplemented with addition a difference operation including the I-counter, together with FPGA experimental result.

  6. A Composite PWM Control Strategy for Boost Converter

    NASA Astrophysics Data System (ADS)

    Qingfeng, Liu; Zhaoxia, Leng; Jinkun, Sun; Huamin, Wang

    In order to improve the control performance of boost converter with large signal disturbance, a composite PWM control strategy for boost converter operating in continuous condition mode (CCM) was proposed in this paper. The parasitical loss of Boost converter was analyzed and a loss compensation strategy was adopted to design feed-forward tracker for converter. The composite PWM controller consisted of the tracker and PID controller. Simulation and experiment results validated the validity of the control strategy presented in this paper.

  7. Temperature prediction in high speed bone grinding using motor PWM signal.

    PubMed

    Tai, Bruce L; Zhang, Lihui; Wang, Anthony C; Sullivan, Stephen; Wang, Guangjun; Shih, Albert J

    2013-10-01

    This research explores the feasibility of using motor electrical feedback to estimate temperature rise during a surgical bone grinding procedure. High-speed bone grinding is often used during skull base neurosurgery to remove cranial bone and approach skull base tumors through the nasal corridor. Grinding-induced heat could propagate and potentially injure surrounding nerves and arteries, and therefore, predicting the temperature in the grinding region would benefit neurosurgeons during the operation. High-speed electric motors are controlled by pulse-width-modulation (PWM) to alter the current input and thus maintain the rotational speed. Assuming full mechanical to thermal power conversion in the grinding process, PWM can be used as feedback for heat generation and temperature prediction. In this study, the conversion model was established from experiments under a variety of grinding conditions and an inverse heat transfer method to determine heat flux. Given a constant rotational speed, the heat conversion was represented by a linear function, and could predict temperature from the experimental data with less than 20% errors. Such results support the advance of this technology for practical application. PMID:23806419

  8. Improved PWM control for GTO inverters with pulse number modulation

    SciTech Connect

    Tadakuma, Susuma; Tanaka, Shigeru; Miura, Kazutoshi; Ofosu-Amaah, W.

    1996-05-01

    This paper proposes pulse number modulation (PNM)-assisted pulse-width modulation (PWM) control to improve the modulation factor of bridge inverters and to solve voltage uncontrollability in neutral point clamped (NPC) inverters. The basic idea is to enlarge the linear region of PWM control via PNM technology. The authors will show the following through simulation and experimental results: (1) conventional bridge inverters can utilize at most 80% of the nominal inverter capacity because of the limit of the modulation factor. The PWM and PNM combined control is able to improve the modulation factor up to approximately 1.0; (2) the PWM and PNM control enables linear voltage control in the NPC inverter even for an extremely small reference. The PNM technology also contributes to a reduction in switching losses.

  9. Monte Carlo Analysis For The Inverse Problem For Motor PWM Control

    NASA Astrophysics Data System (ADS)

    Zhan, Wei

    2009-05-01

    The sensitivity of the steady-state average motor speed for Pulse Width Modulation (PWM) control of DC permanent magnetic motors is analyzed in this paper. Using Maple's symbolic computation capability, an analytic form for the steady-state average motor speed is derived based on a first-principle model. Compared to previous result based on a MATLAB/Simulink model, this analytic form greatly reduces the time required to conduct statistical analysis. As a result, five hundred sets of randomly generated motor parameters are used to determine the standard deviation in the steady-state average motor speed as a function of the standard deviation in the motor parameters. This new approach allows for a detailed sensitivity analysis and the design feasibility study for motor PWM control.

  10. Mixed Modulation Method of PWM Inverter by Considering Acceleration Torque and Voltage Saturation for Speed Servo System

    NASA Astrophysics Data System (ADS)

    Takahashi, Kenji; Ohishi, Kiyoshi; Kanmachi, Tosiyuki

    The speed servo system of an AC motor should always have a rapid and smooth response without current ripple. For this purpose, this paper proposes a new mixed modulation method of the PWM inverter by considering acceleration torque and voltage saturation. The rapid and robust speed servo system often has the high gain speed controller and the high gain current controller. In this case, this speed servo system often has the voltage saturation in the transient state. This paper discusses the amplitude and THD of output voltage on the condition of voltage saturation for each voltage modulation method of three phase inverter such as the carrier comparison inverter using the two phase modulation (2ph. M) and the space voltage vector modulation (SVM) inverter. The carrier comparison inverter using the 2ph. M has the large voltage with large harmonic current. The SVM inverter has the smooth voltage response with small harmonic current. The proposed method switches over the SVM and the 2ph. M methods properly by considering acceleration torque and voltage saturation. The experimental results confirm the effectiveness of the proposed mixed modulation method of the PWM inverter.

  11. Fast controller for a unity-power-factor PWM rectifier

    SciTech Connect

    Eissa, M.O.; Leeb, S.B.; Verghese, G.C.; Stankovic, A.M.

    1996-01-01

    This paper presents an analog implementation of a fast controller for a unity-power-factor (UPF) PWM rectifier. The best settling times of many popular controllers for this type of converter are on the order of a few line cycles, corresponding to bandwidths under 20 Hz. The fast controller demonstrated in this paper can exercise control action at a rate comparable to the switching frequency rather than the line frequency. In order to accomplish this while maintaining unity power factor during steady-state operation, the fast controller employs a ripple-feedback cancellation scheme.

  12. Development of a PWM precision spraying controller for unmanned aerial vehicles

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This paper presents a new pulse width modulation (PWM) controller for unmanned aerial vehicle (UAV) precision sprayer for agriculture using a TL494 fix-frequency pulse width modulator together with a data acquisition board and developed software. The PWM controller was implemented through the guidan...

  13. PWM Inverter control and the application thereof within electric vehicles

    DOEpatents

    Geppert, Steven

    1982-01-01

    An inverter (34) which provides power to an A.C. machine (28) is controlled by a circuit (36) employing PWM control strategy whereby A.C. power is supplied to the machine at a preselectable frequency and preselectable voltage. This is accomplished by the technique of waveform notching in which the shapes of the notches are varied to determine the average energy content of the overall waveform. Through this arrangement, the operational efficiency of the A.C. machine is optimized. The control circuit includes a micro-computer and memory element which receive various parametric inputs and calculate optimized machine control data signals therefrom. The control data is asynchronously loaded into the inverter through an intermediate buffer (38). In its preferred embodiment, the present invention is incorporated within an electric vehicle (10) employing a 144 VDC battery pack (32) and a three-phase induction motor (18).

  14. Efficiency optimal control for AC drives with PWM inverters

    SciTech Connect

    Zach, F.C.; Ertl, H.

    1985-07-01

    For electrical drives using pulsewidth modulation (PWM) inverters and ac motors, methods for efficiency optimal control (EOC) have been developed. They are based on the most complete motor models, including such features as rotor skin effect. Furthermore, new solutions for selected harmonic elimination (SHE) are given. These new solutions come close to EOC. Also, it has been found that EOC solutions (although basically load-dependent as opposed to SHE) do not vary much with the motor used or the motor model applied. Even using a simple R-L series circuit as motor model does not change the solutions much. It is found that using the solutions gained from such a simple model is not more than two points off the real optimum based on a very complete motor model. (For this definition, the absolute harmonic loss minimum is given as zero points, the overall maximum as 100 points with a linear scale in between.) Therefore, one can use one EOC solution for all motors with sufficient accuracy, or, as second best solution, the new form of SHE. Therefore, the EOC solution can be judged load-independent. The implementation by microprocessor-based systems is as easy for other PWM methods. EOC for three and five switching angles per quarter period is discussed, as well as the new solutions for SHE for up to nine angles.

  15. Improved control configuration of PWM rectifiers based on neuro-fuzzy controller.

    PubMed

    Acikgoz, Hakan; Kececioglu, O Fatih; Gani, Ahmet; Yildiz, Ceyhun; Sekkeli, Mustafa

    2016-01-01

    It is well-known that rectifiers are used widely in many applications required AC/DC transformation. With technological advances, many studies are performed for AC/DC converters and many control methods are proposed in order to improve the performance of these rectifiers in recent years. Pulse width modulation (PWM) based rectifiers are one of the most popular rectifier types. PWM rectifiers have lower input current harmonics and higher power factor compared to classical diode and thyristor rectifiers. In this study, neuro-fuzzy controller (NFC) which has robust, nonlinear structure and do not require the mathematical model of the system to be controlled has been proposed for PWM rectifiers. Three NFCs are used in control scheme of proposed PWM rectifier in order to control the dq-axis currents and DC voltage of PWM rectifier. Moreover, simulation studies are carried out to demonstrate the performance of the proposed control scheme at MATLAB/Simulink environment in terms of rise time, settling time, overshoot, power factor, total harmonic distortion and power quality. PMID:27504240

  16. An improved fault-tolerant control scheme for PWM inverter-fed induction motor-based EVs.

    PubMed

    Tabbache, Bekheïra; Benbouzid, Mohamed; Kheloui, Abdelaziz; Bourgeot, Jean-Matthieu; Mamoune, Abdeslam

    2013-11-01

    This paper proposes an improved fault-tolerant control scheme for PWM inverter-fed induction motor-based electric vehicles. The proposed strategy deals with power switch (IGBTs) failures mitigation within a reconfigurable induction motor control. To increase the vehicle powertrain reliability regarding IGBT open-circuit failures, 4-wire and 4-leg PWM inverter topologies are investigated and their performances discussed in a vehicle context. The proposed fault-tolerant topologies require only minimum hardware modifications to the conventional off-the-shelf six-switch three-phase drive, mitigating the IGBTs failures by specific inverter control. Indeed, the two topologies exploit the induction motor neutral accessibility for fault-tolerant purposes. The 4-wire topology uses then classical hysteresis controllers to account for the IGBT failures. The 4-leg topology, meanwhile, uses a specific 3D space vector PWM to handle vehicle requirements in terms of size (DC bus capacitors) and cost (IGBTs number). Experiments on an induction motor drive and simulations on an electric vehicle are carried-out using a European urban driving cycle to show that the proposed fault-tolerant control approach is effective and provides a simple configuration with high performance in terms of speed and torque responses. PMID:23916869

  17. New current control concept -- Minimum time current control in the three-phase PWM converter

    SciTech Connect

    Choi, J.W.; Sul, S.K.

    1997-01-01

    In this paper, a new current controller that guarantees the fastest transient response is proposed. The basic concept is to find the optimal control voltage for tracking the reference current with minimum time under the voltage limit constraint. Though this minimum time control concept is also applicable to all the machine drive systems, this paper focuses on the current regulation in the three-phase pulse width modulation (PWM) converter. In the simulation and experimental results, it is observed that the proposed controller has much less transient time than the conventional synchronous PI regulator and the performance of the dc link voltage control is also greatly improved with the proposed current controller.

  18. Modeling and identification of a solenoid valve for PWM control applications

    NASA Astrophysics Data System (ADS)

    Taghizadeh, M.; Ghaffari, A.; Najafi, F.

    2009-03-01

    In this Note, a nonlinear dynamic model of a PWM-driven pneumatic fast switching valve is presented. The electro-magnetic, mechanical and fluid subsystems of the valve are investigated, including their interactions. Unknown parameters are identified using direct search optimization and model validation is performed by comparing the simulated and measured current curves. In order to use this model in PWM control applications, a simplification strategy is also proposed and a static model is obtained between the duty cycle input and the moving average of the spool position. The simplified static model is validated again by experiments. To cite this article: M. Taghizadeh et al., C. R. Mecanique 337 (2009).

  19. Control of an ultrasonic transducer to realize low speed driven.

    PubMed

    Zhangfan; Chen, Weishan; Liu, Junkao; Zhao, Xuetao

    2006-12-22

    This paper deals with the control of a transducer to realize low speed. A new PWM control is proposed to fit the transducer. By this control method, the transducer is directly excited by pulses whose width can be modulated. The noise induced by conventional PWM control is eliminated and the motor works more steadily and more quietly. Instead of the general method of decreasing vibrating amplitude of ultrasonic motor to realize low speed, in this paper, two fast contrary elliptical vibrations of the transducer's two Langevin vibrators are excited to restrain skip-slip influence on ultrasonic motor's low speed performance and the driven is realized by the difference of the two vibrators' vibrating amplitudes. Experiments had been carried out by driving an aerostatic guide and fuzzy control is applied. The controlled speed reached 0.1 mm/s. PMID:16793079

  20. PWM Strategy and Its Output Control Range of Single-Phase to Three-Phase Matrix Converters

    NASA Astrophysics Data System (ADS)

    Yamashita, Tomomi; Takeshita, Takaharu

    This paper presents a novel PWM strategy for single-phase to three-phase matrix converters with a small capacitor that compensates for single-phase instanteneous electric power fluctuation. Output voltage and input current references are derived for obtaining a unity input power factor. In the proposed PWM strategy, the number of commutations in all the three phases during a control period is reduced to four. A design method for the small capacitor is developed on the basis of the control ranges of the output voltage and current. The effectiveness of the proposed PWM strategy is verified by experiments.

  1. A digitally controlled PWM/PSM dual-mode DC/DC converter

    NASA Astrophysics Data System (ADS)

    Shaowei, Zhen; Bo, Zhang; Ping, Luo; Sijian, Hou; Jingxin, Ye; Xiao, Ma

    2011-11-01

    A digitally controlled pulse width modulation/pulse skip modulation (PWM/PSM) dual-mode buck DC/DC converter is proposed. Its operation mode can be automatically chosen as continuous conduction mode (CCM) or discontinuous conduction mode (DCM). The converter works in PSM at DCM and in 2 MHz PWM at CCM. Switching loss is reduced at a light load by skipping cycles. Thus high conversion efficiency is realized in a wide load current. The implementations of PWM control blocks, such as the ADC, the digital pulse width modulator (DPWM) and the loop compensator, and PSM control blocks are described in detail. The parameters of the loop compensator can be programmed for different external component values and switching frequencies, which is much more flexible than its analog rivals. The chip is manufactured in 0.13 μm CMOS technology and the chip area is 1.21 mm2. Experimental results show that the conversion efficiency is high, being 90% at 200 mA and 67% at 20 mA. Meanwhile, the measured load step response shows that the proposed dual-mode converter has good stability.

  2. Position control of an electro-pneumatic system based on PWM technique and FLC.

    PubMed

    Najjari, Behrouz; Barakati, S Masoud; Mohammadi, Ali; Futohi, Muhammad J; Bostanian, Muhammad

    2014-03-01

    In this paper, modeling and PWM based control of an electro-pneumatic system, including the four 2-2 valves and a double acting cylinder are studied. Dynamic nonlinear behavior of the system, containing fast switching solenoid valves and a pneumatic cylinder, as well as electrical, magnetic, mechanical, and fluid subsystems are modeled. A DC-DC power converter is employed to improve solenoid valve performance and suppress system delay. Among different position control methods, a proportional integrator derivative (PID) controller and fuzzy logic controller (FLC) are evaluated. An experimental setup, using an AVR microcontroller is implemented. Simulation and experimental results verify the effectiveness of the proposed control strategies. PMID:24485509

  3. Vehicle speed control device

    SciTech Connect

    Thornton-Trump, W.E.

    1987-03-10

    An apparatus is described for automatically limiting the speed of a vehicle powered by an internal combustion engine having a spark ignition system with an ignition coil, comprising: sensor means for generating a speed signal directly representative of the speed of the vehicle comprising a series of speed signal pulses having a pulse repetition frequency proportional to the speed of the vehicle; control means for converting speed signal pulses into a DC voltage proportional to the vehicle speed; means for comparing the DC voltage to a predetermined DC voltage having substantially zero AC components representative of a predetermined maximum speed and for generating a difference signal in response thereto; and means for generating a pulse-width modulated control signal responsive to the difference signal; power means responsive to the control signal for intermittently interrupting the ignition system.

  4. Adaptive control in series load PWM induction heating inverters

    NASA Astrophysics Data System (ADS)

    Szelitzky, Tibor; Henrietta Dulf, Eva

    2013-12-01

    Permanent variations of the electric properties of the load in induction heating equipment make difficult to control the plant. To overcome these disadvantages, the authors propose a new approach based on adaptive control methods. For real plants it is enough to present desired performances or start-up variables for the controller, from which the algorithms tune the controllers by itself. To present the advantages of the proposed controllers, comparisons are made to a PI controller tuned through Ziegler-Nichols method.

  5. 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.

  6. Vehicle speed control system

    SciTech Connect

    Yoshida, D.; Tanno, T.; Fukunaga, T.

    1987-06-16

    This patent describes a vehicle speed control system for performing vehicle speed control by controlling the displacement of at least one of a hydraulic pump and a hydraulic motor of a hydraulic transmission through an electric servo device, comprising: vehicle speed setting means for generating a voltage signal corresponding to a vehicle speed to be set; compensating means interposed between the vehicle speed setting means and the electric servo device, the compensating means comprising a first delay element; and second delay element having a response characteristic slower than that of the first delay element. A selecting means for judging as to whether a voltage signal changed by the operation of the vehicle speed setting means represents an acceleration command or a deceleration command and for selecting the first delay element when the voltage signal represents an acceleration command and for selecting the second delay element when the voltage signal represents a deceleration command.

  7. Real-time multi-DSP control of three-phase current-source unity power factor PWM rectifier

    SciTech Connect

    Xiao Wang; Boon-Teck Ooi . Dept. of Electrical Engineering)

    1993-07-01

    The design of a real-time multi-DSP controller for a high-quality six-valve three-phase current-source unity power factor PWM rectifier is discussed in this paper. With the decoupler preprocessor and the dynamic trilogic PWM trigger scheme, each of the three input currents can be controlled independently. Based on the a-b-c frame system model and the fast parallel computer control, the pole-placement control method is implemented successfully to achieve fast response in the ac currents. The low-frequency resonance in the ac filter L-C networks has been damped effectively. The experimental results are obtained from a 1-kVA bipolar transistor current-source PWM rectifier with a real-time controller using three TMS320C25 DSP's.

  8. Engine speed control apparatus

    SciTech Connect

    Ishii, M.; Miyazaki, M.; Nakamura, N.; Kakinuma, H.

    1986-11-04

    This patent describes an engine speed control apparatus. The system comprises an actuator for adjusting an engine speed, a first unit for computing a desired engine speed, a second unit for detecting the actual engine speed, and a third unit for detecting the difference between the outputs of the first and second units. The system also includes a fourth unit for computing a control pulse width for the actuator in accordance with the output of the third unit, a fifth unit for generating a control signal, a sixth unit for driving the actuator in response to the output of the fifth unit, and a seventh unit for computing an optimal halt time to interrupt the driving of the actuator. The actuator is driven intermittently in conformity in the control pulse width and the halt time.

  9. Pulsewidth modulated speed control of brushless dc motors

    NASA Astrophysics Data System (ADS)

    Askinas, A. A.

    1984-09-01

    Until recently, few alternatives existed for the use of hydraulic and pneumatic actuators in primary flight control applications. With the advent of the samarium-cobalt permanent magnet brushless DC motor, consideration must now be given to the utilization of an electromechanical actuator in missiles which require significant maneuvering capability and hence, greater torques. This thesis investigates the theory and techniques of pulse width modulator speed control of brushless DC motors. After describing basic pulse width modulation (PWM) concepts, two constant velocity control schemes are presented: current feedback and a limit cycle scheme. By calculating the motor form factor (a figure of merit for power losses in the switching transistors which comprise the PWM network), the relative worth of each scheme is then evaluated. An in depth study is conducted of the limit cycle approach, with an emphasis on the power loss reductions obtained through the reduction of the velocity limit settings.

  10. Optimum PWM waveform synthesis - a filtering approach

    SciTech Connect

    Divan, D.M.

    1985-09-01

    A fundamentally different approach is proposed for the synthesis of optimum pulsewidth modulated (PWM) waveforms for highpower inverter applications. Conventional optimum PWM waveform synthesis techniques which seek to control harmonic levels in the inverter output directly are seen to be equivalent to a filtering operation. Digital filter structures capable of processing PWM waveforms are examined and waveform synthesis strategies are proposed and verified experimentally. Finally, the design of a high-performance PWM waveform generator is detailed.

  11. Variable speed controller

    NASA Technical Reports Server (NTRS)

    Estes, Christa; Spiggle, Charles; Swift, Shannon; Vangeffen, Stephen; Younger, Frank

    1992-01-01

    This report details a new design for a variable speed controller which can be used to operate lunar machinery without the astronaut using his or her upper body. In order to demonstrate the design, a treadle for an industrial sewing machine was redesigned to be used by a standing operator. Since the invention of an electrically powered sewing machine, the operator has been seated. Today, companies are switching from sit down to stand up operation involving modular stations. The old treadle worked well with a sitting operator, but problems have been found when trying to use the same treadle with a standing operator. Emphasis is placed on the ease of use by the operator along with the ergonomics involved. Included with the design analysis are suggestions for possible uses for the speed controller in other applications.

  12. Digital state feedback control of a three phase sinusoidal PWM inverter

    SciTech Connect

    Matin, Md.A.; Divsalar, D.

    1994-12-31

    This paper proposes a method of three phase voltage control sinusoidal PWM (Pulse Width Modulation) inverter. The state equation of the inverter main circuit has been derived and transformed to the d-q frame. Afterwards, an algorithm of dead-beat control has been developed by considering only the load current as disturbing variable. The advantage of dead-beat control is that it can control very fast within short time (sampling period) comparing to other methods. The main objective of the controller design is to get the sinusoidal voltage at inverter`s output with low harmonic distortions. To compensate the calculation delay and to realize physically, a 3d order prediction method has been adopted. A new switching technique has been developed. This switching technique can reduce unnecessary switching so that switching loss can be minimized. Finally, simulations has been done under a typical load condition (rectifier with capacitor load) and harmonic analysis has also been done. Throughout all simulations, very good results have been found where total harmonic distortions (THD) is less than 5%.

  13. A rule-based fuzzy logic controller for a PWM inverter in a stand alone wind energy conversion scheme

    SciTech Connect

    Hilloowala, R.M.; Sharaf, A.M.

    1996-01-01

    The paper presents a rule-based fuzzy logic controller to control the output power of a pulse width modulated (PWM) inverter used in a stand alone wind energy conversion scheme (SAWECS). The self-excited induction generator used in SAWECS has the inherent problem of fluctuations in the magnitude and frequency of its terminal voltage with changes in wind velocity and load. To overcome this drawback the variable magnitude, variable frequency voltage at the generator terminals is rectified and the dc power is transferred to the load through a PWM inverter. The objective is to track and extract maximum power from the wind energy system (WES) and transfer this power to the local isolated load. This is achieved by using the fuzzy logic controller which regulates the modulation index of the PWM inverter based on the input signals: the power error e = (P{sub ref} {minus} P{sub o}) and its rate of change {dot e}. These input signals are fuzzified, that is defined by a set of linguistic labels characterized by their membership functions predefined for each class. Using a set of 49 rules which relate the fuzzified input signals (e, {dot e}) to the fuzzy controller output U, fuzzy set theory and associated fuzzy logic operations, the fuzzy controller`s output (in terms of linguistic labels) is defuzzified to obtain the actual analog (numerical) output signal which is then used to control the PWM inverter and ensure complete utilization of the available wind energy. The proposed rule-based fuzzy logic controller is simulated and the results are experimentally verified on a scaled down laboratory prototype of the SAWECS.

  14. A novel PWM control for a bi-directional full-bridge DC-DC converter with smooth conversion mode transitions

    NASA Astrophysics Data System (ADS)

    Lorentz, V. R. H.; Schwarzmann, H.; März, M.; Bauer, A. J.; Ryssel, H.; Frey, L.; Poure, P.; Braun, F.

    2011-08-01

    A novel CMOS integrated pulse-width modulation (PWM) control circuit allowing smooth transitions between conversion modes in full-bridge based bi-directional DC-DC converters operating at high switching frequencies is presented. The novel PWM control circuit is able to drive full-bridge based DC-DC converters performing step-down (i.e. buck) and step-up (i.e. boost) voltage conversion in both directions, thus allowing charging and discharging of the batteries in mobile systems. It provides smooth transitions between buck, buck-boost and boost modes. Additionally, the novel PWM control loop circuit uses a symmetrical triangular carrier, which overcomes the necessity of using an output phasing circuit previously required in PWM controllers based on sawtooth oscillators. The novel PWM control also enables to build bi-directional DC-DC converters operating at high switching frequencies (i.e. up to 10 MHz and above). Finally, the proposed PWM control circuit also allows the use of an average lossless inductor-current sensor for sensing the average load current even at very high switching frequencies. In this article, the proposed PWM control circuit is modelled and the integrated CMOS schematic is given. The corresponding theory is analysed and presented in detail. The circuit simulations realised in the Cadence Spectre software with a commercially available 0.18 µm mixed-signal CMOS technology from UMC are shown. The PWM control circuit was implemented in a monolithic integrated bi-directional CMOS DC-DC converter ASIC prototype. The fabricated prototype was tested experimentally and has shown performances in accordance with the theory.

  15. Co-existence of multiple attractors in the PWM controlled DC drives

    NASA Astrophysics Data System (ADS)

    Kundu, Susmita; Kar, Urmila; Chakrabarty, K.

    2013-07-01

    DC shunt and series drives are extensively used in the industry. The occurrence of bifurcation and chaos in dc shunt and permanent magnet drives are well known. It is observed that the behavior of the drives not only depends on the value of system parameters but also on the value of initial conditions. Multiple attractors can exist for same parameter value. Different choice of initial conditions gives different periodic behavior of the system. The drive is intended to operate in a parameter range to give period-1 behavior. We report the existence of sub- harmonic oscillations in the period-1 region of the bifurcation diagram along with co-existing attractor with fractal basin boundaries in PWM controlled dc series drives. The series drive is extensively used in electric traction and other applications. The dc drives are run with dc input voltage. This dc voltage may be derived from a dc source or an ac source with a rectifier. The dc series drive shows different bifurcation behavior when different types of input voltage and switching elements are used. The existence of period-1, period-2 and period-4 orbits are observed with different initial conditions in the desired period-1 region of the bifurcation diagram. The dependence of system's behavior on initial condition may render the system's behavior unpredictable. These phenomena may have serious implication in performance.

  16. Frequency-controlable sine signal based on PWM and its implementation on FPGA

    NASA Astrophysics Data System (ADS)

    Huang, Lianzhen; Li, Jiangang; Zhang, Dongjun

    2012-09-01

    A sine generation method that the different frequent sine signals can be generated by the different Pulse-Width Modulation (PWM) signals generated by Field-Programmable Gate Array (FPGA) through low-pass filter of fixed parameters was proposed. The method just takes a few FPGA resources and was proved feasible by the theory. The experiment results and theory analysis tally.

  17. Speed control for synchronous motors

    NASA Technical Reports Server (NTRS)

    Packard, H.; Schott, J.

    1981-01-01

    Feedback circuit controls fluctuations in speed of synchronous ac motor. Voltage proportional to phase angle is developed by phase detector, rectified, amplified, compared to threshold, and reapplied positively or negatively to motor excitation circuit. Speed control reduces wow and flutter of audio turntables and tape recorders, and enhances hunting in gyroscope motors.

  18. Common-Mode Voltage Characteristics of Matrix Converter According to PWM Method

    NASA Astrophysics Data System (ADS)

    Hara, Hidenori; Yamamoto, Eiji; Yamada, Kenji; Yamanaka, Katsutoshi; Zenke, Michihiko; Kang, Jun-Koo; Kume, Tsuneo Joe

    The matrix converter (MxC) is an ac-to-ac conversion device that can generate variable magnitude variable frequency output voltage. Nine bi-directional switches of MxC allow PWM control of output voltages and input currents. PWM switching needs “switch commutations” from one switch to another. During the switch commutations, however, unwanted voltage error occurs similar to the dead time effects in Voltage Source Inverter (VSI). When PWM pulse width is narrower than the time required for the commutation, voltage error increases rapidly. This voltage distortion is critical in the low speed operation as system becomes sensitive to even a small voltage error. In this paper, a new PWM strategy is proposed for improving voltage control performance in the low voltage region. Based on the input and output voltage information, PWM pulse-widths are controlled to avoid incomplete commutations. The feasibility of the proposed method is proved by simulation and experimental results. In addition, common mode voltage characteristics of MxC are discussed. Common-mode voltage and dv/dt cause motor bearing and ground leakage currents through the parasitic capacitances. Leakage current creates noise problems that can interfere with other equipment. Common-mode voltage characteristics of MxC are presented and discussed using two PWM methods. Simulated and experimental results are presented. Common-mode voltage of two-level VSI and MxC are also compared.

  19. PWM Switching Strategy for Torque Ripple Minimization in BLDC Motor

    NASA Astrophysics Data System (ADS)

    Salah, Wael A.; Ishak, Dahaman; Hammadi, Khaleel J.

    2011-05-01

    This paper describes a new PWM switching strategy to minimize the torque ripples in BLDC motor which is based on sensored rotor position control. The scheme has been implemented using a PIC microcontroller to generate a modified Pulse Width Modulation (PWM) signals for driving power inverter bridge. The modified PWM signals are successfully applied to the next up-coming phase current such that its current rise is slightly delayed during the commutation instant. Experimental results show that the current waveforms of the modified PWM are smoother than that in conventional PWM technique. Hence, the output torque exhibits lower ripple contents.

  20. Simulation and experimental control of a 3-RPR parallel robot using optimal fuzzy controller and fast on/off solenoid valves based on the PWM wave.

    PubMed

    Moezi, Seyed Alireza; Rafeeyan, Mansour; Zakeri, Ehsan; Zare, Amin

    2016-03-01

    In this paper, a robust optimal fuzzy controller based on the Pulse Width Modulation (PWM) technique is proposed to control a laboratory parallel robot using inexpensive on/off solenoid valves. The controller coefficients are determined using Modified Cuckoo Optimization Algorithm. The objective function of this method is considered such that the results show the position tracking by the robot with less force and more efficiency. Regarding the results of experimental tests, the control strategy with on/off valves indicates good performance such that the maximum value of RMS of error for a circular path with increasing force on the system is 3.1mm. Furthermore, the results show the superiority of the optimal fuzzy controller compared with optimal PID controller in tracking paths with different conditions and uncertainties. PMID:26794489

  1. Closed-Loop Motor-Speed Control

    NASA Technical Reports Server (NTRS)

    Smith, Matthew A.; Delcher, Ray C.; Huston, Steven W.

    1989-01-01

    Electronic motor-speed control circuit designed to operate in electrically noisy environment. Includes optoelectronic pick-up device, placed inside motor housing to provide speed feedback signal. Automatically maintains speed motor at commanded value. Measures speed of motor in terms of frequency of pulses of infrared light chopped by fan blades of motor. Difference between measured and commanded speeds serves as control signal for external amplifier driving motor. Major advantage of circuit is low cost.

  2. The effect of La(SSB) on PWM-induced immunoglobulin synthesis by anti-La(SSB) positive SLE patients and healthy controls.

    PubMed Central

    Smith, G; Morrison, C A; Maddison, P J

    1987-01-01

    The effect of affinity purified La(SSB) on immunoglobulin synthesis in vitro by mononuclear cells (MNC) from anti-La(SSB)-positive systemic lupus erythematosus (SLE) patients and healthy controls was studied. La(SSB) was prepared from calf thymus extract and characterized by SDS-polyacrylamide gel electrophoresis and immunoblotting. Silver staining of gels reveals nine major bands at 68 kD, 43-48 kD and 30-33 kD, of which six were recognized on immunoblots by sera from anti-La(SSB) positive SLE patients. Studies in vitro showed that La(SSB) alone did not stimulate total IgG or IgM synthesis in controls or SLE patients. Low concentrations of La(SSB) (optimal dose less than 0.02 ng/ml) suppressed pokeweed mitogen (PWM)-driven IgG synthesis by controls but not by anti-La(SSB) positive SLE patients. IgM responses were unaffected. Anti-La(SSB) and anti-DNA were detected in PWM-stimulated cultures from both study groups. In the presence of La(SSB) IgM anti-La(SSB) synthesis was enhanced in anti-La(SSB)-positive patients in a dose-dependent manner. In contrast, La(SSB) inhibited anti-La(SSB) production by controls (maximal at 2 ng/ml). La(SSB) had no effect on anti-DNA production in either group. Pre-incubation of control or anti-La(SSB)-positive SLE MNC with La(SSB) before addition to autologous PWM-driven cultures did not induce suppressor cells, although pre-incubation with Concanavalin A (ConA) did. Thus we suggest that La(SSB)-induced suppression of IgG synthesis in PWM-driven control cultures may not be due to induction of regulator cells, possibly missing from SLE cultures, but perhaps is a direct effect on B cells. Images Fig. 1 PMID:2958189

  3. FPGA implementation of high-frequency multiple PWM for variable voltage variable frequency controller

    NASA Astrophysics Data System (ADS)

    Boumaaraf, Abdelâali; Mohamadi, Tayeb; Gourmat, Laïd

    2016-07-01

    In this paper, we present the FPGA implementation of the multiple pulse width modulation (MPWM) signal generation with repetition of data segments, applied to the variable frequency variable voltage systems and specially at to the photovoltaic water pumping system, in order to generate a signal command very easily between 10hz to 60 hz with a small frequency and reduce the cost of the control system.

  4. A flexible active and reactive power control strategy for a variable speed constant frequency generating system

    SciTech Connect

    Tang, Y.; Xu, L.

    1995-07-01

    Variable-speed constant-frequency generating systems are used in wind power, hydro power, aerospace, and naval power generations to enhance efficiency and reduce friction. In these applications, an attractive candidate is the slip power recovery system comprising of doubly excited induction machine or doubly excited brushless reluctance machine and PWM converters with a dc link. In this paper, a flexible active and reactive power control strategy is developed, such that the optimal torque-speed profile of the turbine can be followed and overall reactive power can be controlled, while the machine copper losses have been minimized. At the same time, harmonics injected into the power network has also been minimized. In this manner, the system can function as both a high-efficient power generator and a flexible reactive power compensator.

  5. Modeling and Simulation of DSP Controlled SV PWM Three Phase VSI

    NASA Astrophysics Data System (ADS)

    Saadoun, A.; Yousfi, A.; Amirat, Y.

    The present research is concerned with the development of two space vector pulse width modulated VSI models using the software package Matlab. The theoretical principles underlying the space vector modulation technique are presented but have been limited to the few relations needed for the model implementation. The first model, the formulation of which is based on the concept of switching function associated with the semiconductor power switches, is a switched mode inverter while the second model, the sine mode inverter, is formulated in terms of the duty times cycles of the pole switches is a nearly perfect sine wave space vector controlled generator. By comparison to the switched mode inverter, the sine mode inverter exhibits a larger bandwidth to frequency demand. The reliability of the sine mode model has been checked against the experimental results available in the literature provided by Analog Device Corporation.

  6. Low speed phaselock speed control system. [for brushless dc motor

    NASA Technical Reports Server (NTRS)

    Fulcher, R. W.; Sudey, J. (Inventor)

    1975-01-01

    A motor speed control system for an electronically commutated brushless dc motor is provided which includes a phaselock loop with bidirectional torque control for locking the frequency output of a high density encoder, responsive to actual speed conditions, to a reference frequency signal, corresponding to the desired speed. The system includes a phase comparator, which produces an output in accordance with the difference in phase between the reference and encoder frequency signals, and an integrator-digital-to-analog converter unit, which converts the comparator output into an analog error signal voltage. Compensation circuitry, including a biasing means, is provided to convert the analog error signal voltage to a bidirectional error signal voltage which is utilized by an absolute value amplifier, rotational decoder, power amplifier-commutators, and an arrangement of commutation circuitry.

  7. Filtering and Control of High Speed Motor Current in a Flywheel Energy Storage System

    NASA Technical Reports Server (NTRS)

    Kenny, Barbara H.; Santiago, Walter

    2004-01-01

    The NASA Glenn Research Center has been developing technology to enable the use of high speed flywheel energy storage units in future spacecraft for the last several years. An integral part of the flywheel unit is the three phase motor/generator that is used to accelerate and decelerate the flywheel. The motor/generator voltage is supplied from a pulse width modulated (PWM) inverter operating from a fixed DC voltage supply. The motor current is regulated through a closed loop current control that commands the necessary voltage from the inverter to achieve the desired current. The current regulation loop is the innermost control loop of the overall flywheel system and, as a result, must be fast and accurate over the entire operating speed range (20,000 to 60,000 rpm) of the flywheel. The voltage applied to the motor is a high frequency PWM version of the DC bus voltage that results in the commanded fundamental value plus higher order harmonics. Most of the harmonic content is at the switching frequency and above. The higher order harmonics cause a rapid change in voltage to be applied to the motor that can result in large voltage stresses across the motor windings. In addition, the high frequency content in the motor causes sensor noise in the magnetic bearings that leads to disturbances for the bearing control. To alleviate these problems, a filter is used to present a more sinusoidal voltage to the motor/generator. However, the filter adds additional dynamics and phase lag to the motor system that can interfere with the performance of the current regulator. This paper will discuss the tuning methodology and results for the motor/generator current regulator and the impact of the filter on the control. Results at speeds up to 50,000 rpm are presented.

  8. High-Speed Photography with Computer Control.

    ERIC Educational Resources Information Center

    Winters, Loren M.

    1991-01-01

    Describes the use of a microcomputer as an intervalometer for the control and timing of several flash units to photograph high-speed events. Applies this technology to study the oscillations of a stretched rubber band, the deceleration of high-speed projectiles in water, the splashes of milk drops, and the bursts of popcorn kernels. (MDH)

  9. Speed control with end cushion for high speed air cylinder

    DOEpatents

    Stevens, Wayne W.; Solbrig, Charles W.

    1991-01-01

    A high speed air cylinder in which the longitudinal movement of the piston within the air cylinder tube is controlled by pressurizing the air cylinder tube on the accelerating side of the piston and releasing pressure at a controlled rate on the decelerating side of the piston. The invention also includes a method for determining the pressure required on both the accelerating and decelerating sides of the piston to move the piston with a given load through a predetermined distance at the desired velocity, bringing the piston to rest safely without piston bounce at the end of its complete stroke.

  10. Active control system for high speed windmills

    DOEpatents

    Avery, D.E.

    1988-01-12

    A pump stroke is matched to the operating speed of a high speed windmill. The windmill drives a hydraulic pump for a control. Changes in speed of a wind driven shaft open supply and exhaust valves to opposite ends of a hydraulic actuator to lengthen and shorten an oscillating arm thereby lengthening and shortening the stroke of an output pump. Diminishing wind to a stall speed causes the valves to operate the hydraulic cylinder to shorten the oscillating arm to zero. A pressure accumulator in the hydraulic system provides the force necessary to supply the hydraulic fluid under pressure to drive the actuator into and out of the zero position in response to the windmill shaft speed approaching and exceeding windmill stall speed. 4 figs.

  11. Active control system for high speed windmills

    DOEpatents

    Avery, Don E.

    1988-01-01

    A pump stroke is matched to the operating speed of a high speed windmill. The windmill drives a hydraulic pump for a control. Changes in speed of a wind driven shaft open supply and exhaust valves to opposite ends of a hydraulic actuator to lengthen and shorten an oscillating arm thereby lengthening and shortening the stroke of an output pump. Diminishing wind to a stall speed causes the valves to operate the hydraulic cylinder to shorten the oscillating arm to zero. A pressure accumulator in the hydraulic system provides the force necessary to supply the hydraulic fluid under pressure to drive the actuator into and out of the zero position in response to the windmill shaft speed approaching and exceeding windmill stall speed.

  12. Speed control system for a windmill

    SciTech Connect

    Kenney, C.E.

    1981-06-23

    A speed control system for a windmill having blades which can be feathered for altering speed and with the blades under the control of a mechanism which includes a piston assembly and a fluid governor associated therewith. Spring means are used to feather the blades against the force of the piston assembly which is interconnected with the blades, and the speed of blade rotation actually creates the fluid pressure acting on the piston assembly and a governor is associated with the piston assembly for controlling the position of the piston and thus controlling the feathering of the blades, all according to the speed of rotation of the windmill blades. The windmill can be used for generating electric power, and fail-safe mechanisms are employed for protecting in the event of a windmill blade breakage.

  13. Position and speed control of brushless DC motors using sensorless techniques and application trends.

    PubMed

    Gamazo-Real, José Carlos; Vázquez-Sánchez, Ernesto; Gómez-Gil, Jaime

    2010-01-01

    This paper provides a technical review of position and speed sensorless methods for controlling Brushless Direct Current (BLDC) motor drives, including the background analysis using sensors, limitations and advances. The performance and reliability of BLDC motor drivers have been improved because the conventional control and sensing techniques have been improved through sensorless technology. Then, in this paper sensorless advances are reviewed and recent developments in this area are introduced with their inherent advantages and drawbacks, including the analysis of practical implementation issues and applications. The study includes a deep overview of state-of-the-art back-EMF sensing methods, which includes Terminal Voltage Sensing, Third Harmonic Voltage Integration, Terminal Current Sensing, Back-EMF Integration and PWM strategies. Also, the most relevant techniques based on estimation and models are briefly analysed, such as Sliding-mode Observer, Extended Kalman Filter, Model Reference Adaptive System, Adaptive observers (Full-order and Pseudoreduced-order) and Artificial Neural Networks. PMID:22163582

  14. Position and Speed Control of Brushless DC Motors Using Sensorless Techniques and Application Trends

    PubMed Central

    Gamazo-Real, José Carlos; Vázquez-Sánchez, Ernesto; Gómez-Gil, Jaime

    2010-01-01

    This paper provides a technical review of position and speed sensorless methods for controlling Brushless Direct Current (BLDC) motor drives, including the background analysis using sensors, limitations and advances. The performance and reliability of BLDC motor drivers have been improved because the conventional control and sensing techniques have been improved through sensorless technology. Then, in this paper sensorless advances are reviewed and recent developments in this area are introduced with their inherent advantages and drawbacks, including the analysis of practical implementation issues and applications. The study includes a deep overview of state-of-the-art back-EMF sensing methods, which includes Terminal Voltage Sensing, Third Harmonic Voltage Integration, Terminal Current Sensing, Back-EMF Integration and PWM strategies. Also, the most relevant techniques based on estimation and models are briefly analysed, such as Sliding-mode Observer, Extended Kalman Filter, Model Reference Adaptive System, Adaptive observers (Full-order and Pseudoreduced-order) and Artificial Neural Networks. PMID:22163582

  15. Power quality control and design of power converter for variable-speed wind energy conversion system with permanent-magnet synchronous generator.

    PubMed

    Oğuz, Yüksel; Güney, İrfan; Çalık, Hüseyin

    2013-01-01

    The control strategy and design of an AC/DC/AC IGBT-PMW power converter for PMSG-based variable-speed wind energy conversion systems (VSWECS) operation in grid/load-connected mode are presented. VSWECS consists of a PMSG connected to a AC-DC IGBT-based PWM rectifier and a DC/AC IGBT-based PWM inverter with LCL filter. In VSWECS, AC/DC/AC power converter is employed to convert the variable frequency variable speed generator output to the fixed frequency fixed voltage grid. The DC/AC power conversion has been managed out using adaptive neurofuzzy controlled inverter located at the output of controlled AC/DC IGBT-based PWM rectifier. In this study, the dynamic performance and power quality of the proposed power converter connected to the grid/load by output LCL filter is focused on. Dynamic modeling and control of the VSWECS with the proposed power converter is performed by using MATLAB/Simulink. Simulation results show that the output voltage, power, and frequency of VSWECS reach to desirable operation values in a very short time. In addition, when PMSG based VSWECS works continuously with the 4.5 kHz switching frequency, the THD rate of voltage in the load terminal is 0.00672%. PMID:24453905

  16. Power Quality Control and Design of Power Converter for Variable-Speed Wind Energy Conversion System with Permanent-Magnet Synchronous Generator

    PubMed Central

    Oğuz, Yüksel; Güney, İrfan; Çalık, Hüseyin

    2013-01-01

    The control strategy and design of an AC/DC/AC IGBT-PMW power converter for PMSG-based variable-speed wind energy conversion systems (VSWECS) operation in grid/load-connected mode are presented. VSWECS consists of a PMSG connected to a AC-DC IGBT-based PWM rectifier and a DC/AC IGBT-based PWM inverter with LCL filter. In VSWECS, AC/DC/AC power converter is employed to convert the variable frequency variable speed generator output to the fixed frequency fixed voltage grid. The DC/AC power conversion has been managed out using adaptive neurofuzzy controlled inverter located at the output of controlled AC/DC IGBT-based PWM rectifier. In this study, the dynamic performance and power quality of the proposed power converter connected to the grid/load by output LCL filter is focused on. Dynamic modeling and control of the VSWECS with the proposed power converter is performed by using MATLAB/Simulink. Simulation results show that the output voltage, power, and frequency of VSWECS reach to desirable operation values in a very short time. In addition, when PMSG based VSWECS works continuously with the 4.5 kHz switching frequency, the THD rate of voltage in the load terminal is 0.00672%. PMID:24453905

  17. PWM rectifier with low dc voltage ripple for magnet supply

    SciTech Connect

    Ciscato, D. ); Malesani, L.; Rosetto, L.; Tenti, P. ); Basile, G.L.; Pasti, M. ); Voelker, F. )

    1992-04-01

    PWM bridge rectifiers with GTO switches are considered for application to particle accelerator magnet power supplies, where two-quadrant operation and extremely low dc current ripple are required. Different control strategies, with both preprogrammed and variable switching patterns, are examined and compared in view of optimization of the system performance. In particular, optimum digital PWM, multilevel delta modulation, and hybrid PWM/delta techniques are analyzed. In this paper the validity of the control methods is verified by simulation and experimental tests on a 60-kW prototype.

  18. Helicopter low-speed yaw control

    NASA Technical Reports Server (NTRS)

    Wilson, John C. (Inventor); Kelley, Henry L. (Inventor); Crowell, Cynthia A. (Inventor)

    1993-01-01

    A system for improving yaw control at low speeds consists of one strake placed on the upper portion of the fuselage facing the retreating rotor blade and another strake placed on the lower portion of the fuselage facing the advancing rotor blade. These strakes spoil the airflow on the helicopter tail boom during hover, low speed flight, and right or left sidewards flight so that less side thrust is required from the tail rotor.

  19. Speed control system for an access gate

    SciTech Connect

    Bzorgi, Fariborz M.

    2012-03-20

    An access control apparatus for an access gate. The access gate typically has a rotator that is configured to rotate around a rotator axis at a first variable speed in a forward direction. The access control apparatus may include a transmission that typically has an input element that is operatively connected to the rotator. The input element is generally configured to rotate at an input speed that is proportional to the first variable speed. The transmission typically also has an output element that has an output speed that is higher than the input speed. The input element and the output element may rotate around a common transmission axis. A retardation mechanism may be employed. The retardation mechanism is typically configured to rotate around a retardation mechanism axis. Generally the retardation mechanism is operatively connected to the output element of the transmission and is configured to retard motion of the access gate in the forward direction when the first variable speed is above a control-limit speed. In many embodiments the transmission axis and the retardation mechanism axis are substantially co-axial. Some embodiments include a freewheel/catch mechanism that has an input connection that is operatively connected to the rotator. The input connection may be configured to engage an output connection when the rotator is rotated at the first variable speed in a forward direction and configured for substantially unrestricted rotation when the rotator is rotated in a reverse direction opposite the forward direction. The input element of the transmission is typically operatively connected to the output connection of the freewheel/catch mechanism.

  20. Power Electronic Transformer based Three-Phase PWM AC Drives

    NASA Astrophysics Data System (ADS)

    Basu, Kaushik

    A Transformer is used to provide galvanic isolation and to connect systems at different voltage levels. It is one of the largest and most expensive component in most of the high voltage and high power systems. Its size is inversely proportional to the operating frequency. The central idea behind a power electronic transformer (PET) also known as solid state transformer is to reduce the size of the transformer by increasing the frequency. Power electronic converters are used to change the frequency of operation. Steady reduction in the cost of the semiconductor switches and the advent of advanced magnetic materials with very low loss density and high saturation flux density implies economic viability and feasibility of a design with high power density. Application of PET is in generation of power from renewable energy sources, especially wind and solar. Other important application include grid tied inverters, UPS e.t.c. In this thesis non-resonant, single stage, bi-directional PET is considered. The main objective of this converter is to generate adjustable speed and magnitude pulse width modulated (PWM) ac waveforms from an ac or dc grid with a high frequency ac link. The windings of a high frequency transformer contains leakage inductance. Any switching transition of the power electronic converter connecting the inductive load and the transformer requires commutation of leakage energy. Commutation by passive means results in power loss, decrease in the frequency of operation, distortion in the output voltage waveform, reduction in reliability and power density. In this work a source based partially loss-less commutation of leakage energy has been proposed. This technique also results in partial soft-switching. A series of converters with novel PWM strategies have been proposed to minimize the frequency of leakage inductance commutation. These PETs achieve most of the important features of modern PWM ac drives including 1) Input power factor correction, 2) Common

  1. Miniature, Variable-Speed Control Moment Gyroscope

    NASA Technical Reports Server (NTRS)

    Bilski, Steve; Kline-Schoder, Robert; Sorensen, Paul

    2011-01-01

    The Miniature Variable-Speed Control Moment Gyroscope (MVS-CMG) was designed for small satellites (mass from less than 1 kg up to 500 kg). Currently available CMGs are too large and heavy, and available miniature CMGs do not provide sufficient control authority for use on practical satellites. This primarily results from the need to greatly increase the speed of rotation of the flywheel in order to reduce the flywheel size and mass. This goal was achieved by making use of a proprietary, space-qualified, high-speed (100,000 rpm) motor technology to spin the flywheel at a speed ten times faster than other known miniature CMGs under development. NASA is supporting innovations in propulsion, power, and guidance and navigation systems for low-cost small spacecraft. One of the key enabling technologies is attitude control mechanisms. CMGs are particularly attractive for spacecraft attitude control since they can achieve higher torques with lower mass and power than reaction wheels, and they provide continuous torque capability that enables precision pointing (in contrast to on-off thruster control). The aim of this work was to develop a miniature, variable-speed CMG that is sized for use on small satellites. To achieve improved agility, these spacecraft must be able to slew at high rate, which requires attitude control actuators that can apply torques on the order of 5 N-m. The MVS-CMG is specifically designed to achieve a high-torque output with a minimum flywheel and system mass. The flywheel can be run over a wide range of speeds, which is important to help reduce/eliminate potential gimbal lock, and can be used to optimize the operational envelope of the CMG.

  2. Congestion control of high-speed networks

    NASA Astrophysics Data System (ADS)

    1993-06-01

    We report on four areas of activity in the past six months. These areas include the following: (1) work on the control of integrated video and image traffic, both at the access to a network and within a high-speed network; (2) more general/game theoretic models for flow control in networks; (3) work on fault management for high-speed heterogeneous networks to improve survivability; and (4) work on all-optical (lightwave) networks of the future, designed to take advantage of the enormous bandwidth capability available at optical frequencies.

  3. Development of microheaters for gas sensor with an AT-Mega 8535 temperature controller using a PWM (pulse width modulation) method

    NASA Astrophysics Data System (ADS)

    Megayanti, Meti; Panatarani, Camellia; Joni, I. Made

    2016-03-01

    Microheater is the main component in gas sensor characterized by their sensitivity, selectivity, and time response of gas sensor which is depend on the microheater temperature stability. A Cu microheater was developed and utilized AT-Mega 8535 controller using a PWM (pulse width modulation) method. This control system is interfaced to the PC to observe the real time temperature response of the microheater. Three initial resistance (R0) variations of microheater were developed in an open loop control system. The power characteristic of designed microheater depends on the specified microheater initial resistance. The smaller R0, the less power required to reach a temperature setting value. The developed microheater was designed to reach a temperature setting value of 250°C having resistance 0.531 Ω for 1.979 Watt and 0.265 Ω for 1.072 Watt respectively. The results of the investigation on the control performances shows microheater-control system achieved operating temperature up to 250°C. The response of the temperature control shows smallest R0 resulted in a high stability with short settling time, short delay time and small ripple for temperature setting values higher than 150°C. The obtained error of microheater temperature with R0 = 0.265 is 8.596 %. It is concluded that the developed microheater can be utilized as a component of a gas sensor.

  4. Hysteresis modeling of synchronous reluctance motor considering PWM input voltage

    NASA Astrophysics Data System (ADS)

    Lee, J. H.; Kim, J. C.; Hyun, D. S.

    2000-01-01

    This paper deals with the hysteresis characteristics analysis in PWM fed synchronous reluctance motor (SynRM) using a coupled finite element method (FEM) and Preisach's modeling, which is presented to analyze the characteristics under the effect of saturation and hysteresis loss. With regard to the PWM characteristics, a vector control inverter is combined with an analysis tool. Also, a moving mesh technique is used with regard to rotation due to velocity. The focus of this paper is the applied method of Preisach modeling for rotating machines and the characteristics analysis of a SynRM using the proposed method of analysis. For the propriety of proposed method of analysis, TMS320C31 DSP-installed experimental devices are used. And then, computer simulation and experimental result for the i- λ loci, speed, current response, show the propriety of the proposed method. The characteristic analysis is performed in relation to the maximum efficiency condition for a SynRM in simulation and experiment.

  5. 14 CFR 23.373 - Speed control devices.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Speed control devices. 23.373 Section 23....373 Speed control devices. If speed control devices (such as spoilers and drag flaps) are incorporated....441 and 23.443, with the device extended at speeds up to the placard device extended speed; and (b)...

  6. 14 CFR 23.373 - Speed control devices.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Speed control devices. 23.373 Section 23....373 Speed control devices. If speed control devices (such as spoilers and drag flaps) are incorporated....441 and 23.443, with the device extended at speeds up to the placard device extended speed; and (b)...

  7. 14 CFR 23.373 - Speed control devices.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Speed control devices. 23.373 Section 23....373 Speed control devices. If speed control devices (such as spoilers and drag flaps) are incorporated....441 and 23.443, with the device extended at speeds up to the placard device extended speed; and (b)...

  8. 14 CFR 23.373 - Speed control devices.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Speed control devices. 23.373 Section 23....373 Speed control devices. If speed control devices (such as spoilers and drag flaps) are incorporated....441 and 23.443, with the device extended at speeds up to the placard device extended speed; and (b)...

  9. 14 CFR 23.373 - Speed control devices.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Speed control devices. 23.373 Section 23....373 Speed control devices. If speed control devices (such as spoilers and drag flaps) are incorporated....441 and 23.443, with the device extended at speeds up to the placard device extended speed; and (b)...

  10. Novel multilevel inverter carrier-based PWM method

    SciTech Connect

    Tolbert, L.M.; Habetler, T.G.

    1999-10-01

    The advent of the transformerless multilevel inverter topology has brought forth various pulsewidth modulation (PWM) schemes as a means to control the switching of the active devices in each of the multiple voltage levels in the inverter. An analysis of how existing multilevel carrier-based PWM affects switch utilization for the different levels of a diode-clamped inverter is conducted. Two novel carrier-based multilevel PWM schemes are presented which help to optimize or balance the switch utilization in multilevel inverters. A 10-kW prototype six-level diode-clamped inverter has been built and controlled with the novel PWM strategies proposed in this paper to act as a voltage-source inverter for a motor drive.

  11. 14 CFR 25.149 - Minimum control speed.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Minimum control speed. 25.149 Section 25... Minimum control speed. (a) In establishing the minimum control speeds required by this section, the method... prevent a heading change of more than 20 degrees. (e) VMCG, the minimum control speed on the ground,...

  12. 14 CFR 25.149 - Minimum control speed.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Minimum control speed. 25.149 Section 25... Minimum control speed. (a) In establishing the minimum control speeds required by this section, the method... prevent a heading change of more than 20 degrees. (e) VMCG, the minimum control speed on the ground,...

  13. 21 CFR 870.4380 - Cardiopulmonary bypass pump speed control.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cardiopulmonary bypass pump speed control. 870... Cardiopulmonary bypass pump speed control. (a) Identification. A cardiopulmonary bypass pump speed control is a... control the speed of blood pumps used in cardiopulmonary bypass surgery. (b) Classification. Class...

  14. 21 CFR 870.4380 - Cardiopulmonary bypass pump speed control.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Cardiopulmonary bypass pump speed control. 870... Cardiopulmonary bypass pump speed control. (a) Identification. A cardiopulmonary bypass pump speed control is a... control the speed of blood pumps used in cardiopulmonary bypass surgery. (b) Classification. Class...

  15. 14 CFR 25.149 - Minimum control speed.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Minimum control speed. 25.149 Section 25... Minimum control speed. (a) In establishing the minimum control speeds required by this section, the method... prevent a heading change of more than 20 degrees. (e) VMCG, the minimum control speed on the ground,...

  16. 14 CFR 25.149 - Minimum control speed.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Minimum control speed. 25.149 Section 25... Minimum control speed. (a) In establishing the minimum control speeds required by this section, the method... prevent a heading change of more than 20 degrees. (e) VMCG, the minimum control speed on the ground,...

  17. 14 CFR 25.1149 - Propeller speed and pitch controls.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Propeller speed and pitch controls. 25.1149... Accessories § 25.1149 Propeller speed and pitch controls. (a) There must be a separate propeller speed and... synchronization of all propellers. (d) The propeller speed and pitch controls must be to the right of, and...

  18. 14 CFR 25.1149 - Propeller speed and pitch controls.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Propeller speed and pitch controls. 25.1149... Accessories § 25.1149 Propeller speed and pitch controls. (a) There must be a separate propeller speed and... synchronization of all propellers. (d) The propeller speed and pitch controls must be to the right of, and...

  19. 14 CFR 25.1149 - Propeller speed and pitch controls.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Propeller speed and pitch controls. 25.1149... Accessories § 25.1149 Propeller speed and pitch controls. (a) There must be a separate propeller speed and... synchronization of all propellers. (d) The propeller speed and pitch controls must be to the right of, and...

  20. 14 CFR 25.1149 - Propeller speed and pitch controls.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Propeller speed and pitch controls. 25.1149... Accessories § 25.1149 Propeller speed and pitch controls. (a) There must be a separate propeller speed and... synchronization of all propellers. (d) The propeller speed and pitch controls must be to the right of, and...

  1. 14 CFR 25.1149 - Propeller speed and pitch controls.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Propeller speed and pitch controls. 25.1149... Accessories § 25.1149 Propeller speed and pitch controls. (a) There must be a separate propeller speed and... synchronization of all propellers. (d) The propeller speed and pitch controls must be to the right of, and...

  2. Minimum-loss vector PWM strategy for three-phase inverters. [Pulse Width Modulation

    SciTech Connect

    Trzynadlowski, A.M. . Dept. of Electrical Engineering); Legowski, S. . Dept. of Electrical Engineering)

    1994-01-01

    A novel vector Pulse Width Modulation (PWM) method for three-phase voltage-controlled inverters is described. The so-called Minimum-Loss Vector PWM (MLVPWM) strategy is characterized by the minimum amount of switching losses incurred in the inverter switches. Comparative analysis proving superiority of the MLVPWM technique over the existing regular-sampling PWM methods, and results of experimental investigation of a prototype modulator are presented.

  3. Planktonic foraminifera: factors controlling sinking speeds

    NASA Astrophysics Data System (ADS)

    Takahashi, Kozo; Be, Allan W. H.

    1984-12-01

    Sinking speeds of 330 specimens belonging to 10 extant species of planktonic foraminifera were determined in a sinking column device filled with 3°C seawater. The sinking speed is governed primarily by shell weight and presence/absence of spines. For example, preserved planktonic specimens of Orbulina universa, whose shell weight ranged from 2 to 21 μg, sank 122 to 583 m day -1, with a correlation coefficient of 0.92 on log-log scale. Progressive shell thickening during foraminiferal growth accounts for some of the higher sinking speeds. In addition, shells from sediment on the average sink about three times faster than shells (of equivalent size and species) of planktonic foraminifera collected in near-surface waters. These high values are in part due to the shells often being encrusted with clay and nannoplankton remains. In contrast, the sinking speeds of the spinose species are approximately 3-fold slower than those of the non-spinose species. Based on data from plankton tows, most planktonic foraminifera > 150 μm reach the mean ocean depth of 3800 m in 3 to 12 days depending upon shell weight and presence or absence of spines. Estimated Reynolds numbers range from 0.05 to 24.85 and most exceed a value of 0.5 which is an upper for limit Stokes' Law range, suggesting that foraminifera are out of Stokes' sinking range. The Reynolds number and drag coefficients are negatively well correlated, indicating that drag is one of the important controlling factors in the sinking regime. The presence of spines is significant in increasing drag, decreasing the Reynolds number, and hence reducing the sinking speed.

  4. A PWM Buck Converter With Load-Adaptive Power Transistor Scaling Scheme Using Analog-Digital Hybrid Control for High Energy Efficiency in Implantable Biomedical Systems.

    PubMed

    Park, Sung-Yun; Cho, Jihyun; Lee, Kyuseok; Yoon, Euisik

    2015-12-01

    We report a pulse width modulation (PWM) buck converter that is able to achieve a power conversion efficiency (PCE) of > 80% in light loads 100 μA) for implantable biomedical systems. In order to achieve a high PCE for the given light loads, the buck converter adaptively reconfigures the size of power PMOS and NMOS transistors and their gate drivers in accordance with load currents, while operating at a fixed frequency of 1 MHz. The buck converter employs the analog-digital hybrid control scheme for coarse/fine adjustment of power transistors. The coarse digital control generates an approximate duty cycle necessary for driving a given load and selects an appropriate width of power transistors to minimize redundant power dissipation. The fine analog control provides the final tuning of the duty cycle to compensate for the error from the coarse digital control. The mode switching between the analog and digital controls is accomplished by a mode arbiter which estimates the average of duty cycles for the given load condition from limit cycle oscillations (LCO) induced by coarse adjustment. The fabricated buck converter achieved a peak efficiency of 86.3% at 1.4 mA and > 80% efficiency for a wide range of load conditions from 45 μA to 4.1 mA, while generating 1 V output from 2.5-3.3 V supply. The converter occupies 0.375 mm(2) in 0.18 μm CMOS processes and requires two external components: 1.2 μF capacitor and 6.8 μH inductor. PMID:26742139

  5. 14 CFR 23.1149 - Propeller speed and pitch controls.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Propeller speed and pitch controls. 23.1149... Powerplant Controls and Accessories § 23.1149 Propeller speed and pitch controls. (a) If there are propeller speed or pitch controls, they must be grouped and arranged to allow— (1) Separate control of...

  6. 14 CFR 23.1149 - Propeller speed and pitch controls.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Propeller speed and pitch controls. 23.1149... Powerplant Controls and Accessories § 23.1149 Propeller speed and pitch controls. (a) If there are propeller speed or pitch controls, they must be grouped and arranged to allow— (1) Separate control of...

  7. 14 CFR 23.1149 - Propeller speed and pitch controls.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Propeller speed and pitch controls. 23.1149... Powerplant Controls and Accessories § 23.1149 Propeller speed and pitch controls. (a) If there are propeller speed or pitch controls, they must be grouped and arranged to allow— (1) Separate control of...

  8. 14 CFR 23.1149 - Propeller speed and pitch controls.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Propeller speed and pitch controls. 23.1149... Powerplant Controls and Accessories § 23.1149 Propeller speed and pitch controls. (a) If there are propeller speed or pitch controls, they must be grouped and arranged to allow— (1) Separate control of...

  9. 14 CFR 23.1149 - Propeller speed and pitch controls.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Propeller speed and pitch controls. 23.1149... Powerplant Controls and Accessories § 23.1149 Propeller speed and pitch controls. (a) If there are propeller speed or pitch controls, they must be grouped and arranged to allow— (1) Separate control of...

  10. Controlled Speed Accessory Drive demonstration program

    NASA Technical Reports Server (NTRS)

    Hoehn, F. W.

    1981-01-01

    A Controlled Speed Accessory Drive System was examined in an effort to improve the fuel economy of passenger cars. Concept feasibility and the performance of a typical system during actual road driving conditions were demonstrated. The CSAD system is described as a mechanical device which limits engine accessory speeds, thereby reducing parasitic horsepower losses and improving overall vehicle fuel economy. Fuel consumption data were compiled for fleets of GSA vehicles. Various motor pool locations were selected, each representing different climatic conditions. On the basis of a total accumulated fleet usage of nearly three million miles, an overall fuel economy improvement of 6 percent to 7 percent was demonstrated. Coincident chassis dynamometer tests were accomplished on selected vehicles to establish the effect of different accessory drive systems on exhaust emissions, and to evaluate the magnitude of the mileage benefits which could be derived.

  11. Quantum speed problem: Theoretical hints for control

    NASA Astrophysics Data System (ADS)

    Lisboa, Alexandre Coutinho; Piqueira, José Roberto Castilho

    2016-06-01

    The transition time between states plays an important role in designing quantum devices as they are very sensitive to environmental influences. Decoherence phenomenon is responsible for possible destructions of the entanglement that is a fundamental requirement to implement quantum information processing systems. If the time between states is minimized, the decoherence effects can be reduced, thus, it is advantageous to the designer to develop expressions for time performance measures. Quantum speed limit (QSL) problem has been studied from the theoretical point of view, providing general results. Considering the implementation of quantum control systems, as the decoherence phenomenon is unavoidable, it is important to apply these general results to particular cases, developing expressions and performance measures, to assist control engineering designers. Here, a minimum time performance measure is defined for quantum control problems, for time-independent or time-dependent Hamiltonians, and applied to some practical examples, providing hints that may be useful for researchers pursuing optimization strategies for quantum control systems.

  12. Rotor Speed Detection Method for Vector Control of Induction Motor without Speed Sensor Utilizing Slot Harmonics

    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.

  13. Low Speed Control for Automatic Welding

    NASA Technical Reports Server (NTRS)

    Iceland, W. E.

    1982-01-01

    Amplifier module allows rotating positioner of automatic welding machine to operate at speeds below normal range. Low speeds are precisely regulated by a servomechanism as are normal-range speeds. Addition of module to standard welding machine makes it unnecessary to purchase new equipment for low-speed welding.

  14. Speed control of automotive diesel engines

    NASA Astrophysics Data System (ADS)

    Outbib, Rachid; Graton, Guillaume; Dovifaaz, Xavier; Younes, Rafic

    2014-04-01

    This paper deals with Diesel engine control. More precisely, a model-based approach is considered to stabilise engine speed around a defined value. The model taken into account is nonlinear and contains explicitly the expression of fuel conversion efficiency. In general in the literature, this experimentally obtained quantity is modelled with either a polynomial or an exponential form (see for instance Younes, R. (1993). Elaboration d'un modèle de connaissance du moteur diesel avec turbocompresseur à géométrie variable en vue de l'optimisation de ses émissions. Ecole Centrale de Lyon; Omran, R., Younes, R., Champoussin, J., & Outbib, R. (2011). New indicated mean effective pressure (IMEP) model for predicting crankshaft movement. Energy Conversion and Management, 52, 3376-3382). This paper focuses on engine speed feedback stabilisation when fuel conversion efficiency is modelled with an exponential form, which is more suitable for automative applications. Simulation results are proposed to highlight the closed-loop control performances.

  15. 14 CFR 25.373 - Speed control devices.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Speed control devices. 25.373 Section 25... AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Structure Supplementary Conditions § 25.373 Speed control devices. If speed control devices (such as spoilers and drag flaps) are installed for use in en...

  16. 14 CFR 23.1513 - Minimum control speed.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Minimum control speed. 23.1513 Section 23.1513 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... Information § 23.1513 Minimum control speed. The minimum control speed V MC, determined under § 23.149,...

  17. 14 CFR 23.1513 - Minimum control speed.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Minimum control speed. 23.1513 Section 23.1513 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... Information § 23.1513 Minimum control speed. The minimum control speed V MC, determined under § 23.149,...

  18. 14 CFR 25.373 - Speed control devices.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Speed control devices. 25.373 Section 25... AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Structure Supplementary Conditions § 25.373 Speed control devices. If speed control devices (such as spoilers and drag flaps) are installed for use in en...

  19. 14 CFR 25.1513 - Minimum control speed.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Minimum control speed. 25.1513 Section 25.1513 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... Limitations § 25.1513 Minimum control speed. The minimum control speed V MC determined under § 25.149 must...

  20. 14 CFR 25.373 - Speed control devices.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Speed control devices. 25.373 Section 25... AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Structure Supplementary Conditions § 25.373 Speed control devices. If speed control devices (such as spoilers and drag flaps) are installed for use in en...

  1. 14 CFR 23.1513 - Minimum control speed.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Minimum control speed. 23.1513 Section 23.1513 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... Information § 23.1513 Minimum control speed. The minimum control speed V MC, determined under § 23.149,...

  2. 14 CFR 25.1513 - Minimum control speed.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Minimum control speed. 25.1513 Section 25.1513 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... Limitations § 25.1513 Minimum control speed. The minimum control speed V MC determined under § 25.149 must...

  3. 14 CFR 25.1513 - Minimum control speed.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Minimum control speed. 25.1513 Section 25.1513 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... Limitations § 25.1513 Minimum control speed. The minimum control speed V MC determined under § 25.149 must...

  4. 14 CFR 25.373 - Speed control devices.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Speed control devices. 25.373 Section 25... AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Structure Supplementary Conditions § 25.373 Speed control devices. If speed control devices (such as spoilers and drag flaps) are installed for use in en...

  5. 14 CFR 23.1513 - Minimum control speed.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Minimum control speed. 23.1513 Section 23.1513 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... Information § 23.1513 Minimum control speed. The minimum control speed V MC, determined under § 23.149,...

  6. 14 CFR 25.1513 - Minimum control speed.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Minimum control speed. 25.1513 Section 25.1513 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... Limitations § 25.1513 Minimum control speed. The minimum control speed V MC determined under § 25.149 must...

  7. 14 CFR 25.1513 - Minimum control speed.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Minimum control speed. 25.1513 Section 25.1513 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... Limitations § 25.1513 Minimum control speed. The minimum control speed V MC determined under § 25.149 must...

  8. 14 CFR 23.1513 - Minimum control speed.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Minimum control speed. 23.1513 Section 23.1513 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... Information § 23.1513 Minimum control speed. The minimum control speed V MC, determined under § 23.149,...

  9. 14 CFR 25.373 - Speed control devices.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Speed control devices. 25.373 Section 25... AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Structure Supplementary Conditions § 25.373 Speed control devices. If speed control devices (such as spoilers and drag flaps) are installed for use in en...

  10. Adjustable Speed Drive Study, Part 2.

    SciTech Connect

    Wallace, Alan K.; Oregon State University. Dept. of Electrical and Computer Engineering.

    1989-08-01

    Advances in speed control for motors in recent years, notably those in power electronics, have widened the range of application for several adjustable speed drive (ASD) types to include the smaller horsepower sizes. The DC motor drive, formerly in almost universal use for speed control, is being challenged by the high efficiency induction motor/pulse width modulation (PWM) drive; and for special small horsepower size applications, by the permanent magnet motor/PWM inverter drive or by the switched reluctance motor drive. The main characteristics of the several ASD types suitable for small horsepower size applications are discussed, as well as their unwanted side effects: poor power factor, harmonic distortion of the supply, acoustic noise, and electromagnetic interference. A procedure is recommended for determining which, if any, ASD to use.

  11. Adjustable speed drive study, part 1

    NASA Astrophysics Data System (ADS)

    Wallace, A.

    1989-08-01

    Advances in speed control for motors in recent years, notably those in power electronics, have widened the range of application for several adjustable speed drive (ASD) types to include the smaller horsepower sizes. The dc motor drive, formerly in almost universal use for speed control, is being challenged by the high efficiency induction motor/pulse width modulation (PWM) drive; and for special small horsepower size applications, by the permanent magnet motor/PWM inverter drive or by the switched reluctance motor drive. The main characteristics of the several ASD types suitable for small horsepower size applications are discussed, as well as their unwanted side effects: poor power factor, harmonic distortion of the supply, acoustic noise, and electromagnetic interference. A procedure is recommended for determining which, if any, ASD to use.

  12. Adjustable Speed Drive Study, Part 1.

    SciTech Connect

    Wallace, Alan K.; Oregon State University. Dept. of Electrical and Computer Engineering.

    1989-08-01

    Advances in speed control for motors in recent years, notably those in power electronics, have widened the range of application for several adjustable speed drive (ASD) types to include the smaller horsepower sizes. The dc motor drive, formerly in almost universal use for speed control, is being challenged by the high efficiency induction motor/pulse width modulation (PWM) drive; and for special small horsepower size applications, by the permanent magnet motor/PWM inverter drive or by the switched reluctance motor drive. The main characteristics of the several ASD types suitable for small horsepower size applications are discussed, as well as their unwanted side effects: poor power factor, harmonic distortion of the supply, acoustic noise, and electromagnetic interference. A procedure is recommended for determining which, if any, ASD to use. 31 figs., 6 tabs.

  13. On Zero Steady-State Error Voltage Control of Single-Phase PWM Inverters With Different Load Types

    SciTech Connect

    Dong, Dong; Timothy, Thacker; Burgos, Rolando; Wang, Fei; Boroyevich, Dushan

    2011-01-01

    This paper comprehensively investigates and compares different multiloop linear control schemes for single-phase pulsewidth modulation inverters, both in stationary and synchronous (d-q) frames, by focusing on their steady-state error under different loading conditions. Specifically, it is shown how proportional plus resonant (P + R) control and load current feedback (LCF) control can, respectively, improve the steady-state and transient performance of the inverter, leading to the proposal of a PID + R + LCF control scheme. Furthermore, the LCF control and capacitive current feedback control schemes are shown to be subject to stability issues under second and higher order filter loads. Additionally, the equivalence between the stationary frame and d-q frame controllers is discussed depending on the orthogonal term generation method, and a d-q frame voltage control strategy is proposed eliminating the need for the generation of this orthogonal component. This is achieved while retaining all the advantages of operating in the synchronous d-q frame, i.e., zero steady-state error and ease of implementation. All theoretical findings are validated experimentally using a 1.5 kW laboratory prototype.

  14. 49 CFR 236.501 - Forestalling device and speed control.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Forestalling device and speed control. 236.501... Train Stop, Train Control and Cab Signal Systems Standards § 236.501 Forestalling device and speed... the following features: (1) Low-speed restriction, requiring the train to proceed under slow...

  15. 49 CFR 236.501 - Forestalling device and speed control.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Forestalling device and speed control. 236.501... Train Stop, Train Control and Cab Signal Systems Standards § 236.501 Forestalling device and speed... the following features: (1) Low-speed restriction, requiring the train to proceed under slow...

  16. 49 CFR 236.501 - Forestalling device and speed control.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Forestalling device and speed control. 236.501... Train Stop, Train Control and Cab Signal Systems Standards § 236.501 Forestalling device and speed... the following features: (1) Low-speed restriction, requiring the train to proceed under slow...

  17. 49 CFR 236.501 - Forestalling device and speed control.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Forestalling device and speed control. 236.501... Train Stop, Train Control and Cab Signal Systems Standards § 236.501 Forestalling device and speed... the following features: (1) Low-speed restriction, requiring the train to proceed under slow...

  18. 14 CFR 23.149 - Minimum control speed.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Minimum control speed. 23.149 Section 23... Maneuverability § 23.149 Minimum control speed. (a) VMC is the calibrated airspeed at which, when the critical... still inoperative, and thereafter maintain straight flight at the same speed with an angle of bank...

  19. 14 CFR 23.149 - Minimum control speed.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Minimum control speed. 23.149 Section 23... Maneuverability § 23.149 Minimum control speed. (a) VMC is the calibrated airspeed at which, when the critical... still inoperative, and thereafter maintain straight flight at the same speed with an angle of bank...

  20. 49 CFR 236.501 - Forestalling device and speed control.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Forestalling device and speed control. 236.501... Train Stop, Train Control and Cab Signal Systems Standards § 236.501 Forestalling device and speed... the following features: (1) Low-speed restriction, requiring the train to proceed under slow...

  1. Vibration suppression of speed-controlled robots with nonlinear control

    NASA Astrophysics Data System (ADS)

    Boscariol, Paolo; Gasparetto, Alessandro

    2016-06-01

    In this paper, a simple nonlinear control strategy for the simultaneous position tracking and vibration damping of robots is presented. The control is developed for devices actuated by speed-controlled servo drives. The conditions for the asymptotic stability of the closed-loop system are derived by ensuring its passivity. The capability of achieving improved trajectory tracking and vibration suppression is shown through experimental tests conducted on a three-axis Cartesian robot. The control is aimed to be compatible with most industrial applications given the simplicity of implementation, the reduced computational requirements, and the use of joint position as the only measured signal.

  2. Vibration suppression of speed-controlled robots with nonlinear control

    NASA Astrophysics Data System (ADS)

    Boscariol, Paolo; Gasparetto, Alessandro

    2016-04-01

    In this paper, a simple nonlinear control strategy for the simultaneous position tracking and vibration damping of robots is presented. The control is developed for devices actuated by speed-controlled servo drives. The conditions for the asymptotic stability of the closed-loop system are derived by ensuring its passivity. The capability of achieving improved trajectory tracking and vibration suppression is shown through experimental tests conducted on a three-axis Cartesian robot. The control is aimed to be compatible with most industrial applications given the simplicity of implementation, the reduced computational requirements, and the use of joint position as the only measured signal.

  3. Sequential control by speed drive for ac motor

    NASA Astrophysics Data System (ADS)

    Barsoum, Nader

    2012-11-01

    The speed drive for ac motor is widely used in the industrial field to allow direct control for the speed and torque without any feedback from the motor shaft. By using the ABB ACS800 speed drive unit, the speed and torque can be controlled using sequential control method. Sequential control is one of the application control method provided in the ABB ACS800 Drive, where a set of events or action performed in a particular order one after the other to control the speed and torque of the ac motor. It was claimed that sequential control method is using the preset seven constant speeds being provided in ABB ACS800 drive to control the speed and torque in a continuous and sequential manner. The characteristics and features of controlling the speed and torque using sequential control method can be investigated by observing the graphs and curves plotted which are obtained from the practical result. Sequential control can run either in the Direct Torque Control (DTC) or Scalar motor control mode. By using sequential control method, the ABB ACS800 drive can be programmed to run the motor automatically according to the time setting of the seven preset constant speeds. Besides, the intention of this project is to generate a new form of the experimental set up.

  4. Scalar control on speed drive for ac motor

    NASA Astrophysics Data System (ADS)

    Barsoum, Nader

    2012-11-01

    This paper aims to investigate the performance of ABB ACS800 variable speed drive operating under Scalar Control mode, and eventually develop a set of experimental procedures for undergraduate laboratory purposes. Scalar Control is the most widespread form of ac drive, for its low cost and simplicity especially implemented in the open loop mode. Scalar control is achieved by controlling the stator voltage and frequency, thus maintaining the motor's air-gap flux at a constant value. To illustrate the control method, the ac drive is configured according to the wiring diagram in the firmware manual that the drive control location can be both local and external. The drive is selected to operate under Factory application macro, whereby either ordinary speed control applications or constant speeds applications may be used. Under ordinary speed control, frequency reference signals are provided to the drive through the analogue input AI1. The drive will operate at the given frequency reference value throughout the operation regardless of any changes in the load. The torque speed curve moves along the speed axis with no changes to the shape as the supply frequencies changes. On the other hand, the drive allows three preset constant speed through digital inputs DI5 and DI6. The drive operate at a constant speed value over a time period, and only switch from one constant speed to another constant speed by triggering the two input switches. Scalar control is most suitable for applications not required high precision, such as blowers, fans and pumps.

  5. Digital phase-locked-loop speed sensor for accuracy improvement in analog speed controls. [feedback control and integrated circuits

    NASA Technical Reports Server (NTRS)

    Birchenough, A. G.

    1975-01-01

    A digital speed control that can be combined with a proportional analog controller is described. The stability and transient response of the analog controller were retained and combined with the long-term accuracy of a crystal-controlled integral controller. A relatively simple circuit was developed by using phase-locked-loop techniques and total error storage. The integral digital controller will maintain speed control accuracy equal to that of the crystal reference oscillator.

  6. Dithering Digital Ripple Correlation Control for Photovoltaic Maximum Power Point Tracking

    SciTech Connect

    Barth, C; Pilawa-Podgurski, RCN

    2015-08-01

    This study demonstrates a new method for rapid and precise maximum power point tracking in photovoltaic (PV) applications using dithered PWM control. Constraints imposed by efficiency, cost, and component size limit the available PWM resolution of a power converter, and may in turn limit the MPP tracking efficiency of the PV system. In these scenarios, PWM dithering can be used to improve average PWM resolution. In this study, we present a control technique that uses ripple correlation control (RCC) on the dithering ripple, thereby achieving simultaneous fast tracking speed and high tracking accuracy. Moreover, the proposed method solves some of the practical challenges that have to date limited the effectiveness of RCC in solar PV applications. We present a theoretical derivation of the principles behind dithering digital ripple correlation control, as well as experimental results that show excellent tracking speed and accuracy with basic hardware requirements.

  7. A digital input class-D audio amplifier with sixth-order PWM

    NASA Astrophysics Data System (ADS)

    Shumeng, Luo; Dongmei, Li

    2013-11-01

    A digital input class-D audio amplifier with a sixth-order pulse-width modulation (PWM) modulator is presented. This modulator moves the PWM generator into the closed sigma—delta modulator loop. The noise and distortions generated at the PWM generator module are suppressed by the high gain of the forward loop of the sigma—delta modulator. Therefore, at the output of the modulator, a very clean PWM signal is acquired for driving the power stage of the class-D amplifier. A sixth-order modulator is designed to balance the performance and the system clock speed. Fabricated in standard 0.18 μm CMOS technology, this class-D amplifier achieves 110 dB dynamic range, 100 dB signal-to-noise rate, and 0.0056% total harmonic distortion plus noise.

  8. Turbine speed control system based on a fuzzy-PID

    NASA Astrophysics Data System (ADS)

    Sun, Jian-Hua; Wang, Wei; Yu, Hai-Yan

    2008-12-01

    The flexibility demand of marine nuclear power plant is very high, the multiple parameters of the marine nuclear power plant with the once-through steam generator are strongly coupled, and the normal PID control of the turbine speed can’t meet the control demand. This paper introduces a turbine speed Fuzzy-PID controller to coordinately control the steam pressure and thus realize the demand for quick tracking and steady state control over the turbine speed by using the Fuzzy control’s quick dynamic response and PID control’s steady state performance. The simulation shows the improvement of the response time and steady state performance of the control system.

  9. Engine control system having speed-based timing

    DOEpatents

    Willi, Martin L.; Fiveland, Scott B.; Montgomery, David T.; Gong, Weidong

    2012-02-14

    A control system for an engine having a cylinder is disclosed having an engine valve movable to regulate a fluid flow of the cylinder and an actuator associated with the engine valve. The control system also has a controller in communication with the actuator. The controller is configured to receive a signal indicative of engine speed and compare the engine speed signal with a desired engine speed. The controller is also configured to selectively regulate the actuator to adjust a timing of the engine valve to control an amount of air/fuel mixture delivered to the cylinder based on the comparison.

  10. Color adjustable LED driver design based on PWM

    NASA Astrophysics Data System (ADS)

    Du, Yiying; Yu, Caideng; Que, Longcheng; Zhou, Yun; Lv, Jian

    2012-10-01

    Light-emitting diode (LED) is a liquid cold source light source that rapidly develops in recent years. The merits of high brightness efficiency, long duration, high credibility and no pollution make it satisfy our demands for consumption and natural life, and gradually replace the traditional lamp-house-incandescent light and fluorescent light. However, because of the high cost and unstable drive circuit, the application range is restricted. To popularize the applications of the LED, we focus on improving the LED driver circuit to change this phenomenon. Basing on the traditional LED drive circuit, we adopt pre-setup constant current model and introduce pulse width modulation (PWM) control method to realize adjustable 256 level-grays display. In this paper, basing on human visual characteristics and the traditional PWM control method, we propose a new PWM control timing clock to alter the duty cycle of PWM signal to realize the simple gamma correction. Consequently, the brightness can accord with our visual characteristics.

  11. A Sequential Shifting Algorithm for Variable Rotor Speed Control

    NASA Technical Reports Server (NTRS)

    Litt, Jonathan S.; Edwards, Jason M.; DeCastro, Jonathan A.

    2007-01-01

    A proof of concept of a continuously variable rotor speed control methodology for rotorcraft is described. Variable rotor speed is desirable for several reasons including improved maneuverability, agility, and noise reduction. However, it has been difficult to implement because turboshaft engines are designed to operate within a narrow speed band, and a reliable drive train that can provide continuous power over a wide speed range does not exist. The new methodology proposed here is a sequential shifting control for twin-engine rotorcraft that coordinates the disengagement and engagement of the two turboshaft engines in such a way that the rotor speed may vary over a wide range, but the engines remain within their prescribed speed bands and provide continuous torque to the rotor; two multi-speed gearboxes facilitate the wide rotor speed variation. The shifting process begins when one engine slows down and disengages from the transmission by way of a standard freewheeling clutch mechanism; the other engine continues to apply torque to the rotor. Once one engine disengages, its gear shifts, the multi-speed gearbox output shaft speed resynchronizes and it re-engages. This process is then repeated with the other engine. By tailoring the sequential shifting, the rotor may perform large, rapid speed changes smoothly, as demonstrated in several examples. The emphasis of this effort is on the coordination and control aspects for proof of concept. The engines, rotor, and transmission are all simplified linear models, integrated to capture the basic dynamics of the problem.

  12. A novel robust speed controller scheme for PMBLDC motor.

    PubMed

    Thirusakthimurugan, P; Dananjayan, P

    2007-10-01

    The design of speed and position controllers for permanent magnet brushless DC motor (PMBLDC) drive remains as an open problem in the field of motor drives. A precise speed control of PMBLDC motor is complex due to nonlinear coupling between winding currents and rotor speed. In addition, the nonlinearity present in the developed torque due to magnetic saturation of the rotor further complicates this issue. This paper presents a novel control scheme to the conventional PMBLDC motor drive, which aims at improving the robustness by complete decoupling of the design besides minimizing the mutual influence among the speed and current control loops. The interesting feature of this robust control scheme is its suitability for both static and dynamic aspects. The effectiveness of the proposed robust speed control scheme is verified through simulations. PMID:17544426

  13. Variable current speed controller for eddy current motors

    DOEpatents

    Gerth, H.L.; Bailey, J.M.; Casstevens, J.M.; Dixon, J.H.; Griffith, B.O.; Igou, R.E.

    1982-03-12

    A speed control system for eddy current motors is provided in which the current to the motor from a constant frequency power source is varied by comparing the actual motor speed signal with a setpoint speed signal to control the motor speed according to the selected setpoint speed. A three-phase variable voltage autotransformer is provided for controlling the voltage from a three-phase power supply. A corresponding plurality of current control resistors is provided in series with each phase of the autotransformer output connected to inputs of a three-phase motor. Each resistor is connected in parallel with a set of normally closed contacts of plurality of relays which are operated by control logic. A logic circuit compares the selected speed with the actual motor speed obtained from a digital tachometer monitoring the motor spindle speed and operated the relays to add or substract resistance equally in each phase of the motor input to vary the motor current to control the motor at the selected speed.

  14. Speed control of a small turbine using electrical loading.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Small wind turbines with permanent magnet alternators (PMA) seldom have active speed control systems. The turbines rely on passive mechanisms such as furling and/or blade flutter to control the rotational speed. These passive methods cause high mechanical stresses and undesirable noise. One metho...

  15. Avoiding the hazards of pulse-width modulated adjustable-speed drives

    SciTech Connect

    Howe, B.

    1993-12-31

    Pulse-width modulated (PWM) adjustable-speed drives are taking over the market for ASDs under 200 horsepower because they are less expensive and more reliable than competing technologies and because they provide more precise control of motor acceleration, speed, and torque. Misapplication of PWM drives has led to numerous motor failures, however, which could discourage use of this promising technology. Such problems can be readily prevented by careful specification and installation of the drive, the motor, and the cabling between them. What`s behind these costly and inconvenient technical difficulties? They`re caused by interactions between the extremely rapid voltage pulses from the drive and the motor windings, which can lead to excessive voltages that damage the winding insulation and lead to motor failure. PWM drives can also cause radio frequency interference and excessive heating of conduit systems.

  16. A Sensorless Speed Control System for DC Motor Drives

    NASA Astrophysics Data System (ADS)

    Georgiev, Tsolo; Mikhov, Mikho

    2009-01-01

    An approach to sensorless speed control of permanent magnet DC motor drives is presented in this paper. The motor speed has been estimated indirectly by the respective back EMF voltage. Using a discrete vector-matrix description of the controlled object, an optimal modal state observer has been synthesized, as well as an optimal modal controller. The results obtained show that the applied control method can ensure good performance.

  17. Speed sensorless hybrid vector controlled induction motor drive

    SciTech Connect

    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.

  18. Implementation of Temperature Sequential Controller on Variable Speed Drive

    NASA Astrophysics Data System (ADS)

    Cheong, Z. X.; Barsoum, N. N.

    2008-10-01

    There are many pump and motor installations with quite extensive speed variation, such as Sago conveyor, heating, ventilation and air conditioning (HVAC) and water pumping system. A common solution for these applications is to run several fixed speed motors in parallel, with flow control accomplish by turning the motors on and off. This type of control method causes high in-rush current, and adds a risk of damage caused by pressure transients. This paper explains the design and implementation of a temperature speed control system for use in industrial and commercial sectors. Advanced temperature speed control can be achieved by using ABB ACS800 variable speed drive-direct torque sequential control macro, programmable logic controller and temperature transmitter. The principle of direct torque sequential control macro (DTC-SC) is based on the control of torque and flux utilizing the stator flux field orientation over seven preset constant speed. As a result of continuous comparison of ambient temperature to the references temperatures; electromagnetic torque response is particularly fast to the motor state and it is able maintain constant speeds. Experimental tests have been carried out by using ABB ACS800-U1-0003-2, to validate the effectiveness and dynamic respond of ABB ACS800 against temperature variation, loads, and mechanical shocks.

  19. Internal Model Controller of an ANN Speed Sensorless Controlled Induction Motor Drives

    NASA Astrophysics Data System (ADS)

    Hamed Mouna, Ben; Lassaad, Sbita

    This study deals with the performance analysis and implementation of a robust sensorless speed controller. The robustness is guaranteed by the use of the Internal Model Controller (IMC). An intelligent algorithm is evolved to eliminate the mechanical speed. It is based on the Artificial Neural Network (ANN) principle. Verification of the proposed robust sensorless controller is provided by experimental realistic tests on a scalar controlled induction motor drive. Sensorless robust speed control at low speeds and in field weakening region (high speeds) is studied in order to show the robustness of the speed controller under a wide range of load.

  20. Implementation of PMSM speed control software based on CAN bus

    NASA Astrophysics Data System (ADS)

    Cao, Wenlun; Chen, Bei; He, Yuyao

    2013-03-01

    In this paper, the driver's hardware structure based on TMS320F28335 is introduced, the control software flow of host computer based on CAN bus is designed, the rule of CAN communication protocol is fulfilled and accordingly the hybrid programming is realized in the background of low speed and large sinusoid operation. This system can realize the CAN communication setting, download the PID parameters to DSP, operate at constant rotate speed and at given large sinusoid rotate speed. Meanwhile the dynamical monitoring and alarm are implemented. Finally the real-time display and storage of measured current, voltage and rotate speed are completed well.

  1. Redundant speed control for brushless Hall effect motor

    NASA Technical Reports Server (NTRS)

    Nola, F. J. (Inventor)

    1973-01-01

    A speed control system for a brushless Hall effect device equipped direct current (D.C.) motor is described. Separate windings of the motor are powered by separate speed responsive power sources. A change in speed, upward or downward, because of the failure of a component of one of the power sources results in a corrective signal being generated in the other power source to supply an appropriate power level and polarity to one winding to cause the motor to be corrected in speed.

  2. Hardware Evolution of Analog Speed Controllers for a DC Motor

    NASA Technical Reports Server (NTRS)

    Gwaltney, David A.; Ferguson, Michael I.

    2003-01-01

    This viewgraph presentation provides information on the design of analog speed controllers for DC motors on aerospace systems. The presentation includes an overview of controller evolution, evolvable controller configuration, an emphasis on proportion integral (PI) controllers, schematic diagrams, and experimental results.

  3. Using Simulation Speeds to Differentiate Controller Interface Concepts

    NASA Technical Reports Server (NTRS)

    Trujillo, Anna; Pope, Alan

    2008-01-01

    This study investigated two concepts: (1) whether speeding a human-in-the-loop simulation (or the subject's "world") scales time stress in such a way as to cause primary task performance to reveal workload differences between experimental conditions and (2) whether using natural hand motions to control the attitude of an aircraft makes controlling the aircraft easier and more intuitive. This was accomplished by having pilots and non-pilots make altitude and heading changes using three different control inceptors at three simulation speeds. Results indicate that simulation speed does affect workload and controllability. The bank and pitch angle error was affected by simulation speed but not by a simulation speed by controller type interaction; this may have been due to the relatively easy flying task. Results also indicate that pilots could control the bank and pitch angle of an aircraft about equally as well with the glove as with the sidestick. Non-pilots approached the pilots ability to control the bank and pitch angle of an aircraft using the positional glove - where the hand angle is directly proportional to the commanded aircraft angle. Therefore, (1) changing the simulation speed lends itself to objectively indexing a subject s workload and may also aid in differentiating among interface concepts based upon performance if the task being studied is sufficiently challenging and (2) using natural body movements to mimic the movement of an airplane for attitude control is feasible.

  4. Follow the leader: Visual control of speed in pedestrian following

    PubMed Central

    Rio, Kevin W.; Rhea, Christopher K.; Warren, William H.

    2014-01-01

    When people walk together in groups or crowds they must coordinate their walking speed and direction with their neighbors. This paper investigates how a pedestrian visually controls speed when following a leader on a straight path (one-dimensional following). To model the behavioral dynamics of following, participants in Experiment 1 walked behind a confederate who randomly increased or decreased his walking speed. The data were used to test six models of speed control that used the leader's speed, distance, or combinations of both to regulate the follower's acceleration. To test the optical information used to control speed, participants in Experiment 2 walked behind a virtual moving pole, whose visual angle and binocular disparity were independently manipulated. The results indicate the followers match the speed of the leader, and do so using a visual control law that primarily nulls the leader's optical expansion (change in visual angle), with little influence of change in disparity. This finding has direct applications to understanding the coordination among neighbors in human crowds. PMID:24511143

  5. Telemetry Speeds Forest-Fire Control

    NASA Technical Reports Server (NTRS)

    Arvesen, J. C.; Cherbonneaux, J. W.

    1984-01-01

    Airborne system rapidly delivers hard copy to firefighters. Sensors in airplane send data to ground station for image processing. Imagery immediately transferred to U.S. Geologic Survey (USGS) maps by photo interpreter. Maps transmitted by telecopies directly to fire-control camps. Receipt by fire camp less than 10 minutes. Information aids in decisions involving deployment of firefighters and equipment, flood control, monitoring oilspills, observing thermal currents, and pollutions monitoring.

  6. An Automatic Speed Control for Wind Tunnels

    NASA Technical Reports Server (NTRS)

    Zahm, A F

    1928-01-01

    Described here is an automatic control that has been used in several forms in wind tunnels at the Washington Navy Yard. The form now in use with the 8-foot tunnel at the Navy Yard is considered here. Details of the design and operation of the automatic control system are given. Leads from a Pitot tube are joined to an inverted cup manometer located above a rheostat. When the sliding weight of this instrument is set to a given notch, say for 40 m.p.h, the beam tip vibrates between two electric contacts that feed the little motor. Thus, when the wind is too strong or too weak, the motor automatically throws the rheostat slide forward and backward. If it failed to function well, the operator would notice the effect on his meniscus, and would operate the hand control by merely pressing the switch.

  7. Flow Control Effectiveness at High Speed Flows

    NASA Astrophysics Data System (ADS)

    Kontis, K.; Lada, C.

    2005-02-01

    The effects of two important flow control techniques, i.e. jet control and dimples, on the aerodynamic characteristics and performance of a number of body configurations have been studied experimentally. The dimple studies have been carried out in a transonic-supersonic wind tunnel and the jet studies in a hypersonic gun tunnel at a Mach number of 8.2. Air was used as the working gas. The tests employed schlieren photography and oil-flow to study the overall flow field. Quantitative studies have been made by pressure measurements.

  8. Automotive speed control and cruise controls. (Bibliography from the Global Mobility database). Published Search

    SciTech Connect

    1996-08-01

    The bibliography contains citations concerning speed controls and cruise controls for automobiles, trucks, and industrial forklifts. Topics include stability analysis, H-infinity control theory, Proportional Integrative Derivative (PID) control, and idle speed control. The use and effect of controls in various highway situations are reviewed. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

  9. PWM Switching Frequency Effects on Eddy Current Sensors for Magnetically Suspended Flywheel Systems

    NASA Technical Reports Server (NTRS)

    Jansen, Ralph; Lebron, Ramon; Dever, Timothy P.; Birchenough, Arthur G.

    2003-01-01

    A flywheel magnetic bearing (MB) pulse width modulated power amplifier (PWM) configuration is selected to minimize noise generated by the PWMs in the flywheel position sensor system. Two types of noise are addressed: beat frequency noise caused by variations in PWM switching frequencies, and demodulation noise caused by demodulation of high order harmonics of the switching voltage into the MB control band. Beat frequency noise is eliminated by synchronizing the PWM switch frequencies, and demodulation noise is minimized by selection of a switching frequency which does not have harmonics at the carrier frequency of the sensor. The recommended MB PWM system has five synchronized PWMs switching at a non-integer harmonic of the sensor carrier.

  10. Hardware Evolution of Analog Speed Controllers for a DC Motor

    NASA Technical Reports Server (NTRS)

    Gwaltney, David A.; Ferguson, Michael I.

    2003-01-01

    Evolvable hardware provides the capability to evolve analog circuits to produce amplifier and filter functions. Conventional analog controller designs employ these same functions. Analog controllers for the control of the shaft speed of a DC motor are evolved on an evolvable hardware platform utilizing a Field Programmable Transistor Array (FPTA). The performance of these evolved controllers is compared to that of a conventional proportional-integral (PI) controller.

  11. Control structures for high speed processors

    NASA Technical Reports Server (NTRS)

    Maki, G. K.; Mankin, R.; Owsley, P. A.; Kim, G. M.

    1982-01-01

    A special processor was designed to function as a Reed Solomon decoder with throughput data rate in the Mhz range. This data rate is significantly greater than is possible with conventional digital architectures. To achieve this rate, the processor design includes sequential, pipelined, distributed, and parallel processing. The processor was designed using a high level language register transfer language. The RTL can be used to describe how the different processes are implemented by the hardware. One problem of special interest was the development of dependent processes which are analogous to software subroutines. For greater flexibility, the RTL control structure was implemented in ROM. The special purpose hardware required approximately 1000 SSI and MSI components. The data rate throughput is 2.5 megabits/second. This data rate is achieved through the use of pipelined and distributed processing. This data rate can be compared with 800 kilobits/second in a recently proposed very large scale integration design of a Reed Solomon encoder.

  12. Systematic Controller Design Methodology for Variable-Speed Wind Turbines

    SciTech Connect

    Hand, M. M.; Balas, M. J.

    2002-02-01

    Variable-speed, horizontal axis wind turbines use blade-pitch control to meet specified objectives for three operational regions. This paper provides a guide for controller design for the constant power production regime. A simple, rigid, non-linear turbine model was used to systematically perform trade-off studies between two performance metrics. Minimization of both the deviation of the rotor speed from the desired speed and the motion of the actuator is desired. The robust nature of the proportional-integral-derivative controller is illustrated, and optimal operating conditions are determined. Because numerous simulation runs may be completed in a short time, the relationship between the two opposing metrics is easily visualized.

  13. Speed limit and ramp meter control for traffic flow networks

    NASA Astrophysics Data System (ADS)

    Goatin, Paola; Göttlich, Simone; Kolb, Oliver

    2016-07-01

    The control of traffic flow can be related to different applications. In this work, a method to manage variable speed limits combined with coordinated ramp metering within the framework of the Lighthill-Whitham-Richards (LWR) network model is introduced. Following a 'first-discretize-then-optimize' approach, the first order optimality system is derived and the switch of speeds at certain fixed points in time is explained, together with the boundary control for the ramp metering. Sequential quadratic programming methods are used to solve the control problem numerically. For application purposes, experimental setups are presented wherein variable speed limits are used as a traffic guidance system to avoid traffic jams on highway interchanges and on-ramps.

  14. Rotating speed control apparatus for an internal combustion engine

    SciTech Connect

    Umehara, K.

    1987-10-06

    A rotating speed control apparatus is described for controlling the rotating speed of an internal combustion engine, comprising: a capacitive discharge ignition circuit; rotating speed detecting circuit means for monitoring the rotating speed for the engine; overspeed preventing circuit means cooperable with the capacitive discharge ignition circuit and responsive to the rotating speed detecting circuit means; and independently manually actuable cut-off circuit means for disabling the overspeed preventing circuit means so as to prevent the overspeed preventing circuit means from limiting the rotating speed of the engine; wherein the cut-off circuit means includes a reset switch and is actuated in response to manual actuation of the reset switch; wherein the reset switch is a momentary push button switch; wherein following manual actuation of the momentary push button switch the cut-off circuit means remains continuously actuated until the engine is stopped, and wherein at a subsequent restart of the engine the cut-off circuit means is deactuated; wherein the ignition circuit includes a capacitive charging coil, wherein the push button switch has first and second terminals; and wherein the cut-off circuit means includes: a thyristor; a first resistor; a second resistor; a third resistor; a capacitor; first means electrically coupling the capacitive charging coil of the ignition circuit to the first terminal of the push button switch; and second means electrically coupling the anode of the thyristor to the overspeed preventing circuit means.

  15. Neural rotational speed control for wave energy converters

    NASA Astrophysics Data System (ADS)

    Amundarain, M.; Alberdi, M.; Garrido, A. J.; Garrido, I.

    2011-02-01

    Among the benefits arising from an increasing use of renewable energy are: enhanced security of energy supply, stimulation of economic growth, job creation and protection of the environment. In this context, this study analyses the performance of an oscillating water column device for wave energy conversion in function of the stalling behaviour in Wells turbines, one of the most widely used turbines in wave energy plants. For this purpose, a model of neural rotational speed control system is presented, simulated and implemented. This scheme is employed to appropriately adapt the speed of the doubly-fed induction generator coupled to the turbine according to the pressure drop entry, so as to avoid the undesired stalling behaviour. It is demonstrated that the proposed neural rotational speed control design adequately matches the desired relationship between the slip of the doubly-fed induction generator and the pressure drop input, improving the power generated by the turbine generator module.

  16. Implementation of motor speed control using PID control in programmable logic controller

    NASA Astrophysics Data System (ADS)

    Samin, R. E.; Azmi, N. A.; Ahmad, M. A.; Ghazali, M. R.; Zawawi, M. A.

    2012-11-01

    This paper presents the implementation of motor speed control using Proportional Integral Derrivative (PID) controller using Programmable Logic Controller (PLC). Proportional Integral Derrivative (PID) controller is the technique used to actively control the speed of the motor. An AC motor is used in the research together with the PLC, encoder and Proface touch screen. The model of the PLC that has been used in this project is OMRON CJIG-CPU42P where this PLC has a build in loop control that can be made the ladder diagram quite simple using function block in CX-process tools. A complete experimental analysis of the technique in terms of system response is presented. Comparative assessment of the impact of Proportional, Integral and Derivative in the controller on the system performance is presented and discussed.

  17. Controlled Speed Accessory Drive Program: Programmatic environmental assessment

    SciTech Connect

    Not Available

    1980-04-14

    This document is a programmatic environmental assessment of the Department of Energy's Controlled Speed Accessory Drive (CSAD) program and alternatives. Its purpose is to evaluate CSAD alternatives to assure that environmental priorities are considered at the earliest meaningful point in the decision-making process, and to facilitate the choice of preferable options. This document accords with both the letter and the spirit of the National Environmental Policy Act (NEPA) requirements as interpreted and standardized by the Council on Environmental Quality. The major conclusions reached in this assessment are as follows: (1) controlled speed accessory drive bolted onto existing automobile designs may not provide adequate engine cooling when operated at high ambient temperatures or under heavy loading; (2) when the CSAD is adopted for production, the emissions effect of controlled speed accessory drive will not be a problem. Auto emissions are already controlled by existing regulations, and automobiles with a CSAD must meet the same emission standards as non-CSAD vehicles; (3) the nature of the impact is such that significant expansion of the market will not affect it. The one adverse environmental concern, the engine cooling problem, will probably be remedied by proper optimization of automobiles for controlled speed accessory drive, or, until the problem can be alleviated, it will delay commercialization of the drive. No safety hazard will be introduced to the American roadways. In addition, no adverse environmental concerns directly related to the Controlled Speed Accessory Drive demonstration program are anticipated. Therefore, it is recommended that a finding of no significant impact be prepared.

  18. 14 CFR 23.149 - Minimum control speed.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... operating. (d) A minimum speed to intentionally render the critical engine inoperative must be established... engine is suddenly made inoperative, it is possible to maintain control of the airplane with that engine... not more than 5 degrees. The method used to simulate critical engine failure must represent the...

  19. 14 CFR 23.149 - Minimum control speed.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... operating. (d) A minimum speed to intentionally render the critical engine inoperative must be established... engine is suddenly made inoperative, it is possible to maintain control of the airplane with that engine... not more than 5 degrees. The method used to simulate critical engine failure must represent the...

  20. 14 CFR 23.149 - Minimum control speed.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... operating. (d) A minimum speed to intentionally render the critical engine inoperative must be established... engine is suddenly made inoperative, it is possible to maintain control of the airplane with that engine... not more than 5 degrees. The method used to simulate critical engine failure must represent the...

  1. 6. GOVERNOR AND SPEED CONTROL MECHANISMS TANK, AT LEFT AN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. GOVERNOR AND SPEED CONTROL MECHANISMS TANK, AT LEFT AN ACCUMULATOR TANK WHICH STORE AIR PRESSURE TO OPEN GATES AND GET GENERATOR STARTED. LARGE TANK AT RIGHT IS THE MAIN GUARD VALVE FOR THE GENERATOR - Los Angeles Aqueduct, Haiwee Power Plant, Los Angeles, Los Angeles County, CA

  2. Multivariable Techniques for High-Speed Research Flight Control Systems

    NASA Technical Reports Server (NTRS)

    Newman, Brett A.

    1999-01-01

    This report describes the activities and findings conducted under contract with NASA Langley Research Center. Subject matter is the investigation of suitable multivariable flight control design methodologies and solutions for large, flexible high-speed vehicles. Specifically, methodologies are to address the inner control loops used for stabilization and augmentation of a highly coupled airframe system possibly involving rigid-body motion, structural vibrations, unsteady aerodynamics, and actuator dynamics. Design and analysis techniques considered in this body of work are both conventional-based and contemporary-based, and the vehicle of interest is the High-Speed Civil Transport (HSCT). Major findings include: (1) control architectures based on aft tail only are not well suited for highly flexible, high-speed vehicles, (2) theoretical underpinnings of the Wykes structural mode control logic is based on several assumptions concerning vehicle dynamic characteristics, and if not satisfied, the control logic can break down leading to mode destabilization, (3) two-loop control architectures that utilize small forward vanes with the aft tail provide highly attractive and feasible solutions to the longitudinal axis control challenges, and (4) closed-loop simulation sizing analyses indicate the baseline vane model utilized in this report is most likely oversized for normal loading conditions.

  3. Adjustable speed drive study, June 1985 to September 1988. Part 2: Appendices

    NASA Astrophysics Data System (ADS)

    Wallace, Alan

    1989-08-01

    Advances in speed control for motors in recent years, notably those in power electronics, have widened the range of application for several adjustable speed drive (ASD) types to include the smaller horsepower sizes. The dc motor drive, formerly in almost universal use for speed control, is being challenged by the high efficiency induction motor/pulse width modulation (PWM) drive; and for special small horsepower size applications, by the permanent magnet motor/PWM inverter drive or by the switched reluctance motor drive. The main characteristics of the several ASD types suitable for small horsepower size applications are discussed, as well as their unwanted side effects: poor power factor, harmonic distortion of the supply, acoustic noise, and electromagnetic interference. A procedure is recommended for determining which, if any, ASD to use.

  4. Precision electronic speed controller for an alternating-current motor

    DOEpatents

    Bolie, V.W.

    A high precision controller for an alternating-current multi-phase electrical motor that is subject to a large inertial load. The controller was developed for controlling, in a neutron chopper system, a heavy spinning rotor that must be rotated in phase-locked synchronism with a reference pulse train that is representative of an ac power supply signal having a meandering line frequency. The controller includes a shaft revolution sensor which provides a feedback pulse train representative of the actual speed of the motor. An internal digital timing signal generator provides a reference signal which is compared with the feedback signal in a computing unit to provide a motor control signal. The motor control signal is a weighted linear sum of a speed error voltage, a phase error voltage, and a drift error voltage, each of which is computed anew with each revolution of the motor shaft. The speed error signal is generated by a novel vernier-logic circuit which is drift-free and highly sensitive to small speed changes. The phase error is also computed by digital logic, with adjustable sensitivity around a 0 mid-scale value. The drift error signal, generated by long-term counting of the phase error, is used to compensate for any slow changes in the average friction drag on the motor. An auxillary drift-byte status sensor prevents any disruptive overflow or underflow of the drift-error counter. An adjustable clocked-delay unit is inserted between the controller and the source of the reference pulse train to permit phase alignment of the rotor to any desired offset angle. The stator windings of the motor are driven by two amplifiers which are provided with input signals having the proper quadrature relationship by an exciter unit consisting of a voltage controlled oscillator, a binary counter, a pair of read-only memories, and a pair of digital-to-analog converters.

  5. Magnetic Bearing Controller Improvements for High Speed Flywheel System

    NASA Technical Reports Server (NTRS)

    Dever, Timothy P.; Brown, Gerald V.; Jansen, Ralph H.; Kascak, Peter E.; Provenza, Andrew J.

    2003-01-01

    A magnetic bearing control system for a high-speed flywheel system is described. The flywheel utilizes a five axis active magnetic bearing system, using eddy current sensors for position feedback to the bearing controller. Magnetic bearing controller features designed to improve flywheel operation and testing are described. Operational improvements include feed forward control to compensate for rotor imbalance, moving notch filtering to compensate for synchronous and harmonic rotational noise, and fixed notching to prevent rotor bending mode excitation. Testing improvements include adding safe gain, bearing current hold, bearing current zero, and excitation input features. Performance and testing improvements provided by these features are measured and discussed.

  6. A Novel 500kW High-Speed Turbine PM Synchronous Generator Set for Distributed Power Generation

    NASA Astrophysics Data System (ADS)

    Wendt, Sven; Benecke, Frank; Güldner, Henry

    The paper presents a power generation system based on the cogeneration of heat and electricity with a novel high speed turbogenerator. The machine consists of a single stage steam turbine and a directly coupled permanent magnet synchronous generator in one constructional unit. A PWM IGBT rectifier is the load to the generator and a PWM IGBT three-phase four-wire inverter feeds the power into the low voltage mains. In order to increase the turbine efficiency at light load, variable speed operation of the turbogenerator is realized. Different control schemes for mains parallel operation and stand alone operation are presented. The control schemes allow for the use of a lookup table based control with a speed-power-characteristic or for the use of a maximum power point tracker. Measurement results from the successfully tested turbogenerator set are presented.

  7. A speed feedback control strategy for car-following model

    NASA Astrophysics Data System (ADS)

    Zhu, Wen-Xing; Zhang, Li-Dong

    2014-11-01

    A speed feedback control mechanism was introduced into the system to improve the dynamical performance of the traffic flow. The modern control theory was used to analyze the stability of the system. It is found that the stability region varies with the feedback coefficient proportionally. In addition, the unit step responses in time domain and phase-frequency curves in frequency domain were given with different feedback coefficients in step response diagram and Bode diagram respectively. The overshoot and phase margins are inversely proportional to the speed feedback coefficients in an underdamped condition. The simulations were conducted to verify the validity of the improvement. The conclusion can be drawn that the analytical result and the simulation result are in good agreement with each other.

  8. Precision electronic speed controller for an alternating-current

    DOEpatents

    Bolie, Victor W.

    1988-01-01

    A high precision controller for an alternating-current multi-phase electrical motor that is subject to a large inertial load. The controller was developed for and is particularly suitable for controlling, in a neutron chopper system, a heavy spinning rotor that must be rotated in phase-locked synchronism with a reference pulse train that is representative of an ac power supply signal having a meandering line frequency. The controller includes a shaft revolution sensor which provides a feedback pulse train representative of the actual speed of the motor. An internal digital timing signal generator provides a reference signal which is compared with the feedback signal in a computing unit to provide a motor control signal. In the preferred embodiment, the motor control signal is a weighted linear sum of a speed error voltage, a phase error voltage, and a drift error voltage, each of which is computed anew with each revolution of the motor shaft. The stator windings of the motor are driven by two amplifiers which are provided with input signals having the proper quadrature relationship by an exciter unit consisting of a voltage controlled oscillator, a binary counter, a pair of readonly memories, and a pair of digital-to-analog converters.

  9. Speed Control of General Purpose Engine with Electronic Governor

    NASA Astrophysics Data System (ADS)

    Sawut, Umerujan; Tohti, Gheyret; Takigawa, Buso; Tsuji, Teruo

    This paper presents a general purpose engine speed control system with an electronic governor in order to improve the current system with a mechanical governor which shows unstable characteristics by change of mecanical friction or A/F ratio (Air/Fuel ratio). For the control system above, there are problems that the feedback signal is only a crank angle because of cost and the controlled object is a general purpose engine which is strongly nonlinear. In order to overcome these problems, the system model is shown for the dynamic estimation of the amount of air flow and the robust controller is designed. That is, the proposed system includes the robust sliding-mode controller by the feedback signal of only a crank angle where Genetic Algorithm is applied for the controller design. The simulation and the experiments by MATLAB/Simulink are performed to show the effectiveness of our proposal.

  10. Speed control system design and experimentation for interior PMSM drives

    NASA Astrophysics Data System (ADS)

    Quang Dang, Dong; Thi-Thuy Vu, Nga; Choi, Han Ho; Jung, Jin-Woo

    2015-05-01

    This paper presents a robust speed-control strategy using a Takagi-Sugeno fuzzy model for interior permanent magnet synchronous motor (IPMSM) drives. The sufficient conditions of linear matrix inequalities, which can guarantee the existence of the fuzzy controller gains, are derived from a common quadratic Lyapunov function. Moreover, the maximum torque per ampere control is incorporated to improve the torque production in the constant torque region and the efficiency of the IPMSM drive. The global stability of an observer-based control system is analytically proven. Simulations and experiments are conducted to demonstrate the feasibility of the proposed approach through a prototype IPMSM drive system. Consequently, the proposed fuzzy control methodology can achieve less steady-state error and less sensitivity than the conventional feedback linearisation control method under motor parameter variations and external disturbances.

  11. Vector control and fuzzy logic control of doubly fed variable speed drives with DSP implementation

    SciTech Connect

    Tang, Y.; Xu, L.

    1995-12-01

    Field orientation control and fuzzy logic control are designed for variable speed drive systems with a doubly fed machine in slip power recovery configuration. Laboratory implementation with a general purpose DSP (digital signal processing) system is described and experimental results are given. High performance potential of a slip power recovery system is realized with these advanced controls, while flexible reactive power control becomes possible, and compared to the ordinary variable speed drives with singly fed induction machine, power converter rating is reduced.

  12. High speed parametric processing controlled by few photons

    NASA Astrophysics Data System (ADS)

    Pejkic, Ana; Radic, Stojan

    2015-11-01

    Optical signal processing has long been recognized as a promising route to a new class of fast and energy efficient devices. The former parameter, the speed, has indeed been addressed in a number of different signal processing roles, confirming the superiority of optical signal processing devices with respect to their electronic counterpart. After gaining some maturity, the field has now advanced to reducing the energy consumption. In this regard, new efforts are directed toward designing an efficient photon interaction mediator, expected to provide both fast and energy efficient devices. The key topic of this review is the progress in longitudinal silica fiber dispersion engineering enabling efficient, non-reciprocal parametric mixers. We present how longitudinal dispersion fluctuations, once considered detrimental, can now be exploited to alter the phase matching condition, and thus, enable fast control of a high power beam by few photons. The potential of such a functionality in high-speed optical signal processing and sensing is discussed.

  13. Speed control of switched reluctance motor using sliding mode control strategy

    SciTech Connect

    John, G.; Eastham, A.R.

    1995-12-31

    A robust speed drive system for a switched reluctance motor (SRM) using sliding mode control strategy (SLMC) is presented. After reviewing the operation of an SRM drive, a SLMC based scheme is formulated to control the drive speed. The scheme is implemented using a micro-controller and a high resolution position sensor. The parameter insensitive characteristics are demonstrated through computer simulations and experimental verification.

  14. The hippocampus participates in the control of locomotion speed.

    PubMed

    López Ruiz, J R; Osuna Carrasco, L P; López Valenzuela, C L; Franco Rodríguez, N E; de la Torre Valdovinos, B; Jiménez Estrada, I; Dueñas Jiménez, J M; Dueñas Jiménez, S H

    2015-12-17

    The hippocampus role in sensory-motor integration remains unclear. In these experiments we study its function in the locomotor control. To establish the connection between the hippocampus and the locomotor system, electrical stimulation in the CA1 region was applied and EMG recordings were obtained. We also evaluated the hindlimbs and forelimbs kinematic patterns in rats with a penetrating injury (PI) in the hippocampus as well as in a cortex-injured group (CI), which served as control. After the PI, tamoxifen a selective estrogen receptor modulator (SERM) that has been described as a neuroprotector and antiinflammatory drug, or vehicle was administered. Electrical stimulation in the hippocampus produces muscle contractions in the contralateral triceps, when 6 Hz or 8 Hz pulse trains were applied. The penetrating injury in the hippocampus reduced the EMG amplitude after the electrical stimulation. At 7 DPI (days post-injury) we observed an increase in the strides speed in all four limbs of the non-treated group, decreasing the correlation percentage of the studied joints. After 15 DPI the strides speed in the non-treated returned to normal. These changes did not occur in the tamoxifen group nor in cortex-injured group. After 30 days, the nontreated group presented a reduction in the number of pyramidal cell layer neurons at the injury site, in comparison to the tam-treated group. The loss of neurons, may cause the interruption of the trisynaptic circuit and changes in the locomotion speed. Tamoxifen preserves the pyramidal neurons after the injury, probably resulting in the strides speed recovery. PMID:26597762

  15. Speed Isn't Everything: Complex Processing Speed Measures Mask Individual Differences and Developmental Changes in Executive Control

    ERIC Educational Resources Information Center

    Cepeda, Nicholas J.; Blackwell, Katharine A.; Munakata, Yuko

    2013-01-01

    The rate at which people process information appears to influence many aspects of cognition across the lifespan. However, many commonly accepted measures of "processing speed" may require goal maintenance, manipulation of information in working memory, and decision-making, blurring the distinction between processing speed and executive control and…

  16. A current-type PWM rectifier with active damping function

    SciTech Connect

    Sato, Yukihiko; Kataoka, Teruo

    1996-05-01

    A new control method for current-type pulse-width modulation (PWM) rectifiers which can provide active damping function is presented. This damping function is effective only on the harmonic components of ac input current selectively. Thus steady-state waveform distortion and transient oscillation of the input current are reduced by the active damping effects. The active damping function can be realized by feedback control of an LC filter connected to the ac side of the rectifier, and it does not require any additional components in the main circuits, permitting a simple circuit configuration. The control system of the proposed PWM rectifier is analyzed by using a simple block diagram developed in the present paper. From the analytical results, the influence of the circuit parameters and control delay on the active damping effects and the stability of the operation are clarified to establish the design method. To confirm the effectiveness of the active damping function, some results of basic experiments are included. As an example of application of the active damping function, the proposed rectifier is applied to reduce the harmonic currents generated by conventional rectifiers operating in parallel with the proposed rectifier. Some experimental results in this application are also included.

  17. Inverter Output Filter Effect on PWM Motor Drives of a Flywheel Energy Storage System

    NASA Technical Reports Server (NTRS)

    Santiago, Walter

    2004-01-01

    NASA Glenn Research Center (GRC) has been involved in the research and development of high speed flywheel systems for small satellite energy storage and attitude control applications. One research and development area has been the minimization of the switching noise produced by the pulsed width modulated (PWM) inverter that drives the flywheel permanent magnet motor/generator (PM M/G). This noise can interfere with the flywheel M/G hardware and the system avionics hampering the full speed performance of the flywheel system. One way to attenuate the inverter switching noise is by placing an AC filter at the three phase output terminals of the inverter with the filter neutral point connected to the DC link (DC bus) midpoint capacitors. The main benefit of using an AC filter in this fashion is the significant reduction of the inverter s high dv/dt switching and its harmonics components. Additionally, common mode (CM) and differential mode (DM) voltages caused by the inverter s high dv/dt switching are also reduced. Several topologies of AC filters have been implemented and compared. One AC filter topology consists of a two-stage R-L-C low pass filter. The other topology consists of the same two-stage R-L-C low pass filter with a series connected trap filter (an inductor and capacitor connected in parallel). This paper presents the analysis, design and experimental results of these AC filter topologies and the comparison between the no filter case and conventional AC filter.

  18. Low-Speed Active Flow Control Laboratory Developed

    NASA Technical Reports Server (NTRS)

    Culley, Dennis E.; Bright, Michelle M.

    2005-01-01

    The future of aviation propulsion systems is increasingly focused on the application of control technologies to significantly enhance the performance of a new generation of air vehicles. Active flow control refers to a set of technologies that manipulate the flow of air and combustion gases deep within the confines of an engine to dynamically alter its performance during flight. By employing active flow control, designers can create engines that are significantly lighter, are more fuel efficient, and produce lower emissions. In addition, the operating range of an engine can be extended, yielding safer transportation systems. The realization of these future propulsion systems requires the collaborative development of many base technologies to achieve intelligent, embedded control at the engine locations where it will be most effective. NASA Glenn Research Center s Controls and Dynamics Technology Branch has developed a state-of-the-art low-speed Active Flow Control Laboratory in which emerging technologies can be integrated and explored in a flexible, low-cost environment. The facility allows the most promising developments to be prescreened and optimized before being tested on higher fidelity platforms, thereby reducing the cost of experimentation and improving research effectiveness.

  19. Adaptive torque control of variable speed wind turbines

    NASA Astrophysics Data System (ADS)

    Johnson, Kathryn E.

    Wind is a clean, renewable resource that has become more popular in recent years due to numerous advances in technology and public awareness. Wind energy is quickly becoming cost competitive with fossil fuels, but further reductions in the cost of wind energy are necessary before it can grow into a fully mature technology. One reason for higher-than-necessary cost of the wind energy is uncertainty in the aerodynamic parameters, which leads to inefficient controllers. This thesis explores an adaptive control technique designed to reduce the negative effects of this uncertainty. The primary focus of this work is a new adaptive controller that is designed to resemble the standard non-adaptive controller used by the wind industry. The standard controller was developed for variable speed wind turbines operating below rated power. The new adaptive controller uses a simple, highly intuitive gain adaptation law intended to seek out the optimal gain for maximizing the turbine's energy capture. It is designed to work even in real, time-varying winds. The adaptive controller has been tested both in simulation and on a real turbine, with numerous experimental results provided in this work. Simulations have considered the effects of erroneous wind measurements and time-varying turbine parameters, both of which are concerns on the real turbine. The adaptive controller has been found to operate as desired under realistic operating conditions, and energy capture has increased on the real turbine as a result. Theoretical analyses of the standard and adaptive controllers were performed, as well, providing additional insight into the system. Finally, a few extensions were made with the intent of making the adaptive control idea even more appealing in the commercial wind turbine market.

  20. Fractional order PID controller for improvement of PMSM speed control in aerospace applications

    NASA Astrophysics Data System (ADS)

    Saraji, Ali Motalebi; Ghanbari, Mahmood

    2014-12-01

    Because of the benefits reduced size, cost and maintenance, noise, CO2 emissions and increased control flexibility and precision, to meet these expectations, electrical equipment increasingly utilize in modern aircraft systems and aerospace industry rather than conventional mechanic, hydraulic, and pneumatic power systems. Electric motor drives are capable of converting electrical power to drive actuators, pumps, compressors, and other subsystems at variable speeds. In the past decades, permanent magnet synchronous motor (PMSM) and brushless dc (BLDC) motor were investigated for aerospace applications such as aircraft actuators. In this paper, the fractional-order PID controller is used in the design of speed loop of PMSM speed control system. Having more parameters for tuning fractional order PID controller lead to good performance ratio to integer order. This good performance is shown by comparison fractional order PID controller with the conventional PI and tuned PID controller by Genetic algorithm in MATLAB soft wear.

  1. Fractional order PID controller for improvement of PMSM speed control in aerospace applications

    SciTech Connect

    Saraji, Ali Motalebi; Ghanbari, Mahmood

    2014-12-10

    Because of the benefits reduced size, cost and maintenance, noise, CO2 emissions and increased control flexibility and precision, to meet these expectations, electrical equipment increasingly utilize in modern aircraft systems and aerospace industry rather than conventional mechanic, hydraulic, and pneumatic power systems. Electric motor drives are capable of converting electrical power to drive actuators, pumps, compressors, and other subsystems at variable speeds. In the past decades, permanent magnet synchronous motor (PMSM) and brushless dc (BLDC) motor were investigated for aerospace applications such as aircraft actuators. In this paper, the fractional-order PID controller is used in the design of speed loop of PMSM speed control system. Having more parameters for tuning fractional order PID controller lead to good performance ratio to integer order. This good performance is shown by comparison fractional order PID controller with the conventional PI and tuned PID controller by Genetic algorithm in MATLAB soft wear.

  2. Method and system for controlling a rotational speed of a rotor of a turbogenerator

    DOEpatents

    Stahlhut, Ronnie Dean; Vuk, Carl Thomas

    2008-12-30

    A system and method controls a rotational speed of a rotor or shaft of a turbogenerator in accordance with a present voltage level on a direct current bus. A lower threshold and a higher threshold are established for a speed of a rotor or shaft of a turbogenerator. A speed sensor determines speed data or a speed signal for the rotor or shaft associated with a turbogenerator. A voltage regulator adjusts a voltage level associated with a direct current bus within a target voltage range if the speed data or speed signal indicates that the speed is above the higher threshold or below the lower threshold.

  3. Reliable 3-phase PWM boost rectifiers employing a stacked dual boost converter subtopology

    SciTech Connect

    Salmon, J.C.

    1996-05-01

    This paper describes circuit topologies for 3-phase pulse-width modulation (PWM) boost rectifiers that operate with a unity fundamental power factor and a low-distortion ac line current. Overlap delays between the switching of the upper and lower devices in a PWM rectifier leg are not critical and diodes eliminates the possibility of the dc-link capacitor discharging into short circuits and shoot-through fault conditions. The rectifiers are controlled using a stacked dual boost converter cell subtopology model that can be used in two current control modes. The dual current-control mode shapes two line currents and can achieve current distortion levels below 5%. The single current-control mode shapes one line current and can achieve current distortion levels close to 5% with the rectifier output dc voltage at the standard level associated with a rectified mains voltage. The per-unit current ratings for the switches in the 3-phase PWM switch networks are around 15--20% of the input rms line current as compared to 71% for a standard 3-phase PWM rectifier. Circuit simulations and experimental results are used to demonstrate the performance and feasibility of the rectifiers described.

  4. Control methods for high-speed supercavitating vehicles

    NASA Astrophysics Data System (ADS)

    Vanek, Balint

    Supercavitation is an emerging technology that enables underwater vehicles to reach unprecedented speed. With proper design of cavitator attached to the vehicle nose, the vehicle body is surrounded by water vapor cavity, eliminating skin friction drag. This technology offers unprecedented drag reduction, though poses problems for vehicle design. The gas bubble surrounding the hull introduces highly coupled dynamic behavior, representing a challenge for the control designer. Development of stable, controllable supercavitating vehicles requires solution for several open problems. This dissertation addresses the problem of control oriented modeling, stability augmentation, and reference tracking using parameter dependent control techniques for supercavitating vehicles. The thesis is divided into three parts. A nonlinear dynamical model capturing the most important properties of the vehicle motion is developed from a control design perspective. The model includes memory effects associated with the time evolution of the cavity and uses lookup tables to determine forces. To aid understanding the cavity-vehicle interaction, a longitudinal control scenario is developed for a simplified longitudinal dynamical model with guaranteed properties. Significant insight is gained on planing behavior and operating envelope using constrained control inputs. Extending the longitudinal control problem, a linear parameter varying model of the coupled motion is developed to provide a platform for parameter dependent control synthesis. The mathematical model is scheduled with aerodynamic angles, uses steady-state approximation of the cavity, leading to uncertainty in the governing equations. Two Linear Parameter Varying (LPV) controllers are synthesized for the angle rate tracking problem, taking uncertainty into account. One uses traditional decoupled loops for pitch-, roll- and yaw-rate tracking. Ignoring the cross coupling, leads to more tractable subproblems. A controller, taking

  5. Distributed control architecture of high-speed networks

    NASA Astrophysics Data System (ADS)

    Cidon, Israel; Gopal, Inder; Kaplan, Marc A.; Kutten, Shay

    1995-05-01

    A control architecture for a high-speed packet-switched network is described. The architecture was designed and implemented as part of the PARIS (subsequently plaNET and BBNS) networking project at IBM. This high bandwidth network for integrated communication (data, voice, video) is currently operational as a laboratory prototype. It will also be deployed within the AURORA Testbed that is part of the NSF/DARPA gigabit networking program. The high bandwidth dictates the need for specialized hardware to support faster packet handling for both point-to-point and multicast connections. A faster and more efficient network control is also required in order to support the increased number of connections and their changing requirements with time. The new network control architecture presented exploits specialized hardware, thereby enabling tasks to be performed faster and with less computation overhead. In particular, since control information can be distributed quickly using hardware packet handling mechanisms, decisions can be made based upon more complete and accurate information. In some respects, this has the effect of having the benefits of centralized control (e.g., easier bandwidth resource allocation to connections), while retaining the fault tolerance and scalability of a distributed architecture.

  6. Performance analysis of SHE-PWM using Fourier Series and Newton-Raphson analysis

    NASA Astrophysics Data System (ADS)

    Lada, M. Y.; Khiar, M. S. A.; Ghani, S. A.; Nawawi, M. R. M.; Nor, A. S. M.; Yuen, J. G. M.

    2015-05-01

    The performance of inverter has become a vital role in contributing effective power system nowadays. However the major issue that will reduce the inverter performance is the harmonic distortions that contribute to power losses. Thus, there are a variety of controls techniques have been implemented for inverters switching such as square wave, SHE-PWM, unipolar and bipolar. The square wave type inverter produces output voltage in square shape which has simple logic control and power switches. Next, unipolar and bipolar techniques are using comparator to compare the reference voltage waveform with the triangular waveform. The difference between unipolar and bipolar is there are two reference signals which are compared with the triangular waveform for unipolar switching. On the other hand, bipolar switching compares triangular waveform with a reference signal. Selective Harmonic Elimination Pulse-Width Modulation (SHE-PWM) is another control technique for inverters. This research propose SHE-PWM as a low switching frequency strategy that uses Fourier Series and Newton-Raphson analysis to calculate the switching angles for elimination of harmonic distortion. Fourier Series is used to determine the amplitude of any odd harmonic in the output signal whereas Newton-Raphson is used to solve the equation for finding switching angles. As a result, SHE-PWM can select the low frequency harmonic components need to be eliminated and reduce the harmonic distortion. It also prevents the harmonic distortion that sensitive to the inverter performance

  7. A new low-cost, fully fault-protected PWM-VSI inverter with true phase-current information

    SciTech Connect

    Blaabjerg, F.; Pedersen, J.K.

    1997-01-01

    This paper proposes a new topology for a low-cost three-phase pulse width modulation (PWM) VSI inverter where a true phase current information exists with the use of only one current sensor in the dc link. The topology also has the benefits of full protection of the inverter such as short circuits in the dc link, output phase faults, and output earth faults. Previously suggested methods have problems at low speed in detecting the phase current, but by the use of space vector modulation in a double-sided implementation, the PWM-pulses are adjusted so true information about the phase current exists even at very low speed. The dc link current is sampled twice during one switching period, and it is proposed to sample in the center of the PWM-pulses to obtain a real average phase current. The effects of blanking-time and overmodulation are also discussed. The strategy is implemented in a 16-b microcontroller, and the test results show the technique is useful in the whole speed range. It is concluded by the use of the proposed topology that only one current sensor will be necessary in the future for PWM-VSI inverters.

  8. Highly Precise Rotational Speed Control by a Hybrid of PLL and Repetitive Control

    NASA Astrophysics Data System (ADS)

    Machida, Hidekazu; Inoue, Takashi; Kobayashi, Fuminori

    PLL speed control system has excellent ‘macroscopic’, or long-term, steadiness. However, ‘microscopic’ speed fluctuation is another important issue. It is called ‘cogging,’ caused by electro-magnetic structural property of motor. Although repetitive control is useful for reducing such fluctuation, stability condition is hard to be satisfied for PLL which inevitably includes integrator. In this article, we propose a D repetitive controller to ease this condition. Rather simple implementation with an FPGA and effective experimental results revealing 60% reduction in fluctuation are shown.

  9. Low-Speed Stability-and-Control and Ground-Effects Measurements on the Industry Reference High Speed Civil Transport

    NASA Technical Reports Server (NTRS)

    Kemmerly, Guy T.; Campbell, Bryan A.; Banks, Daniel W.; Yaros, Steven F.

    1999-01-01

    As a part of a national effort to develop an economically feasible High Speed Civil Transport (HSCT), a single configuration has been accepted as the testing baseline by the organizations working in the High Speed Research (HSR) program. The configuration is based on a design developed by the Boeing Company and is referred to as the Reference H (Ref H). The data contained in this report are low-speed stability-and-control and ground-effect measurements obtained on a 0.06 scale model of the Ref H in a subsonic tunnel.

  10. Motor cortical control of movement speed with implications for brain-machine interface control

    PubMed Central

    Golub, Matthew D.; Yu, Byron M.; Schwartz, Andrew B.

    2014-01-01

    Motor cortex plays a substantial role in driving movement, yet the details underlying this control remain unresolved. We analyzed the extent to which movement-related information could be extracted from single-trial motor cortical activity recorded while monkeys performed center-out reaching. Using information theoretic techniques, we found that single units carry relatively little speed-related information compared with direction-related information. This result is not mitigated at the population level: simultaneously recorded population activity predicted speed with significantly lower accuracy relative to direction predictions. Furthermore, a unit-dropping analysis revealed that speed accuracy would likely remain lower than direction accuracy, even given larger populations. These results suggest that the instantaneous details of single-trial movement speed are difficult to extract using commonly assumed coding schemes. This apparent paucity of speed information takes particular importance in the context of brain-machine interfaces (BMIs), which rely on extracting kinematic information from motor cortex. Previous studies have highlighted subjects' difficulties in holding a BMI cursor stable at targets. These studies, along with our finding of relatively little speed information in motor cortex, inspired a speed-dampening Kalman filter (SDKF) that automatically slows the cursor upon detecting changes in decoded movement direction. Effectively, SDKF enhances speed control by using prevalent directional signals, rather than requiring speed to be directly decoded from neural activity. SDKF improved success rates by a factor of 1.7 relative to a standard Kalman filter in a closed-loop BMI task requiring stable stops at targets. BMI systems enabling stable stops will be more effective and user-friendly when translated into clinical applications. PMID:24717350

  11. Large-signal stability analysis of PWM converters

    SciTech Connect

    Huynh, P.T.; Cho, B.H.

    1995-12-31

    Investigation of the effects of existing nonlinearities on the stability of PWM converters is performed. The bilinear structure, the duty cycle saturation, and the opamp saturation are the principal nonlinearities in PWM converters. These nonlinearities are incorporated in the large-signal analytical models of PWM converters, and the basic input-output stability theory is applied to analyze their stability. Design and optimization of the small-signal loop gains to counteract the undesirable nonlinear effects are also discussed.

  12. FASTBUS Readout Controller card for high speed data acquisition

    SciTech Connect

    Zimmermann, S. Rio Grande do Sul Univ., Porto Alegre, RS . Dept. of Electrical Engineering); Areti, V.H.; Foster, G.W.; Joshi, U.; Treptow, K. )

    1991-10-01

    This article describes a FASTBUS Readout Controller (FRC) for high speed data acquisition in FASTBUS based systems. The controller has two main interfaces: to FASTBUS and to a Readout Port. The FASTBUS interface performs FASTBUS master and slave operations at a maximum transfer rate exceeding 40 MBytes/s. The Readout Port can be adapted for a variety of protocols. Currently, it will be interfaced to a VME bus based processor with a VSB port. The on-board LR33000 embedded processor controls the readout, executing a list of operations download into its memory. It scans the FASTBUS modules and stores the data in a triple port DRAM (TPDRAM), through one of the Serial Access Memory (SAM) ports of the (TPDRAM). Later, it transfers this data to the readout port using the other SAM. The FRC also supports serial communication via RS232 and Ethernet interfaces. This device is intended for use in the data acquisition system at the Collider Detector at Fermilab. 5 refs., 3 figs.

  13. 30 CFR 57.9101 - Operating speeds and control of equipment.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Operating speeds and control of equipment. 57... Loading, Hauling, and Dumping Traffic Safety § 57.9101 Operating speeds and control of equipment.... Operating speeds shall be consistent with conditions of roadways, tracks, grades, clearance, visibility,...

  14. 30 CFR 57.9101 - Operating speeds and control of equipment.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Operating speeds and control of equipment. 57... Loading, Hauling, and Dumping Traffic Safety § 57.9101 Operating speeds and control of equipment.... Operating speeds shall be consistent with conditions of roadways, tracks, grades, clearance, visibility,...

  15. 30 CFR 57.9101 - Operating speeds and control of equipment.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Operating speeds and control of equipment. 57... Loading, Hauling, and Dumping Traffic Safety § 57.9101 Operating speeds and control of equipment.... Operating speeds shall be consistent with conditions of roadways, tracks, grades, clearance, visibility,...

  16. 30 CFR 56.9101 - Operating speeds and control of equipment.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Operating speeds and control of equipment. 56... Loading, Hauling, and Dumping Traffic Safety § 56.9101 Operating speeds and control of equipment.... Operating speeds shall be consistent with conditions of roadways, tracks, grades, clearance, visibility,...

  17. 30 CFR 56.9101 - Operating speeds and control of equipment.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Operating speeds and control of equipment. 56... Loading, Hauling, and Dumping Traffic Safety § 56.9101 Operating speeds and control of equipment.... Operating speeds shall be consistent with conditions of roadways, tracks, grades, clearance, visibility,...

  18. 30 CFR 56.9101 - Operating speeds and control of equipment.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Operating speeds and control of equipment. 56... Loading, Hauling, and Dumping Traffic Safety § 56.9101 Operating speeds and control of equipment.... Operating speeds shall be consistent with conditions of roadways, tracks, grades, clearance, visibility,...

  19. 30 CFR 57.9101 - Operating speeds and control of equipment.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Operating speeds and control of equipment. 57... Loading, Hauling, and Dumping Traffic Safety § 57.9101 Operating speeds and control of equipment.... Operating speeds shall be consistent with conditions of roadways, tracks, grades, clearance, visibility,...

  20. 30 CFR 56.9101 - Operating speeds and control of equipment.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Operating speeds and control of equipment. 56... Loading, Hauling, and Dumping Traffic Safety § 56.9101 Operating speeds and control of equipment.... Operating speeds shall be consistent with conditions of roadways, tracks, grades, clearance, visibility,...

  1. 30 CFR 57.9101 - Operating speeds and control of equipment.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Operating speeds and control of equipment. 57... Loading, Hauling, and Dumping Traffic Safety § 57.9101 Operating speeds and control of equipment.... Operating speeds shall be consistent with conditions of roadways, tracks, grades, clearance, visibility,...

  2. 30 CFR 56.9101 - Operating speeds and control of equipment.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Operating speeds and control of equipment. 56... Loading, Hauling, and Dumping Traffic Safety § 56.9101 Operating speeds and control of equipment.... Operating speeds shall be consistent with conditions of roadways, tracks, grades, clearance, visibility,...

  3. Active vibration control for high speed train bogies

    NASA Astrophysics Data System (ADS)

    Peiffer, Alexander; Storm, Stefan; Röder, Arno; Maier, Rudolf; Frank, Paul-Gerhard

    2005-02-01

    This report deals with the design of an active vibration control (AVC) system integrated into the primary suspension of the bogie of a German high-speed train (ICE). As a design case a prototype bogie (WU92) for the ICE2 was taken. This paper comprises all parts and stages of the development of an AVC system. First, a transfer path analysis was performed in order to identify the main paths of propagation and to determine the boundary conditions at the actuator contact points. A detailed FE-analysis performed on the basis of an already existing FE-model serves as a support to investigate the actuator performance and evaluate several actuator concepts. However, the evaluation of a multifold of varying configurations of actuator, error sensor and monitor sensor positions is obviously not possible in the experiment, but is in the simulation. Based on the simulations and the experiments the control system is implemented on a digital signal processor (DSP) system. The structure borne noise level was determined during running tests at the ICE3 and measurements at the WU92 installed in the test rig. The design of the actuator system includes the layout of the specific system as well as the selection of the piezoelectric elements. A specifically developed amplifier drives the actuators. Finally the system is integrated into one axle of the WU92 and tested during roller-rig measurements.

  4. A Novel Three-Phase UPS Inverter Driven by Error-Tracking-Mode PWM Scheme

    NASA Astrophysics Data System (ADS)

    Ohshima, Masaaki; Nakamura, Fuminori; Tamai, Shinzo; Yamamoto, Yuushin; Yoshida, Kouichi

    With prevalence of information technology into our modern society and advance of automation technology in modern production process, the UPS market is assumed to make sustainable expansion. Error-Tracking-Mode PWM scheme offers novel constantly-sampled current-regulated switching algorithm to voltage-source power converters. This paper proposes a UPS in which Error-Tracking-Mode PWM scheme is applied to the current minor loop. The upper voltage control loop (ac-AVR) is developed afresh, that makes best of the PWM attributes. The equivalent output impedance of the UPS is derived theoretically for not only small signal but also large signal operation, that value can be arbitrarily specified by the ac-AVR parameters. A 3 kVA experimental setup was designed and fabricated, which has demonstrated the theoretical characteristics satisfactorily. The paper discusses the experimental results in detail. The authors believe that the paper presents a clue to realize independent and autonomic operation of dispersed PWM converters.

  5. Prediction of 2-level PWM inverter efficiency using MATLAB/Simulink

    NASA Astrophysics Data System (ADS)

    Kim, Yoon-Ho; Kim, Seong-Je

    2015-10-01

    This article proposes a direct approach for the prediction of inverter efficiency using MATLAB/Simulink, instead of an indirect loss calculation approach based on analytical models. In analytical approach, efficiency is obtained by calculating individual losses separately, such as switching losses, conduction losses and harmonic losses using analytical models. However, this approach requires accurate analytical models and complicated calculations, due to the variation in the switching frequency, switching transient and modulation techniques. In the proposed approach, the actual waveform of the inverter system is directly generated using MATLAB/Simulink. The instantaneous voltage and current waveform including switching transients are generated. Thus, the proposed approach is very simple and convenient for efficiency prediction. The proposed approach also works for any system parameters or control methods, such as various pulse-width modulation (PWM) techniques, different switching frequencies, switching devices and load types. The proposed approach can be adopted for the efficiency prediction of any switching strategies and any types of inverters such as neutral-point-clamped (NPC) inverters, H bridge inverters and H5 topology, since the topologies are modelled as circuits in the MATLAB/Simulink program and no analytical model is required for the proposed approach. Furthermore, the proposed approach can provide operation techniques and conditions such as PWM techniques and switching frequency that offer high efficiency. In this article, inverter performance is evaluated for various PWM techniques and switching frequencies. The PWM technique and switching frequency that offer high efficiency is obtained. Finally, the proposed approach is verified by experimental results.

  6. A new method for speed control of a DC motor using magnetorheological clutch

    NASA Astrophysics Data System (ADS)

    Nguyen, Quoc Hung; Choi, Seung-Bok

    2014-03-01

    In this research, a new method to control speed of DC motor using magnetorheological (MR) clutch is proposed and realized. Firstly, the strategy of a DC motor speed control using MR clutch is proposed. The MR clutch configuration is then proposed and analyzed based on Bingham-plastic rheological model of MR fluid. An optimal designed of the MR clutch is then studied to find out the optimal geometric dimensions of the clutch that can transform a required torque with minimum mass. A prototype of the optimized MR clutch is then manufactured and its performance characteristics are experimentally investigated. A DC motor speed control system featuring the optimized MR clutch is designed and manufactured. A PID controller is then designed to control the output speed of the system. In order to evaluate the effectiveness of the proposed DC motor speed control system, experimental results of the system such as speed tracking performance are obtained and presented with discussions.

  7. Type-2 fuzzy logic control based MRAS speed estimator for speed sensorless direct torque and flux control of an induction motor drive.

    PubMed

    Ramesh, Tejavathu; Kumar Panda, Anup; Shiva Kumar, S

    2015-07-01

    In this research study, a model reference adaptive system (MRAS) speed estimator for speed sensorless direct torque and flux control (DTFC) of an induction motor drive (IMD) using two adaptation mechanism schemes are proposed to replace the conventional proportional integral controller (PIC). The first adaptation mechanism scheme is based on Type-1 fuzzy logic controller (T1FLC), which is used to achieve high performance sensorless drive in both transient as well as steady state conditions. However, the Type-1 fuzzy sets are certain and unable to work effectively when higher degree of uncertainties presents in the system which can be caused by sudden change in speed or different load disturbances, process noise etc. Therefore, a new Type-2 fuzzy logic controller (T2FLC) based adaptation mechanism scheme is proposed to better handle the higher degree of uncertainties and improves the performance and also robust to various load torque and sudden change in speed conditions, respectively. The detailed performances of various adaptation mechanism schemes are carried out in a MATLAB/Simulink environment with a speed sensor and speed sensorless modes of operation when an IMD is operating under different operating conditions, such as, no-load, load and sudden change in speed, respectively. To validate the different control approaches, the system also implemented on real-time system and adequate results are reported for its validation. PMID:25887841

  8. Analysis and control of high-speed wheeled vehicles

    NASA Astrophysics Data System (ADS)

    Velenis, Efstathios

    In this work we reproduce driving techniques to mimic expert race drivers and obtain the open-loop control signals that may be used by auto-pilot agents driving autonomous ground wheeled vehicles. Race drivers operate their vehicles at the limits of the acceleration envelope. An accurate characterization of the acceleration capacity of the vehicle is required. Understanding and reproduction of such complex maneuvers also require a physics-based mathematical description of the vehicle dynamics. While most of the modeling issues of ground-vehicles/automobiles are already well established in the literature, lack of understanding of the physics associated with friction generation results in ad-hoc approaches to tire friction modeling. In this work we revisit this aspect of the overall vehicle modeling and develop a tire friction model that provides physical interpretation of the tire forces. The new model is free of those singularities at low vehicle speed and wheel angular rate that are inherent in the widely used empirical static models. In addition, the dynamic nature of the tire model proposed herein allows the study of dynamic effects such as transients and hysteresis. The trajectory-planning problem for an autonomous ground wheeled vehicle is formulated in an optimal control framework aiming to minimize the time of travel and maximize the use of the available acceleration capacity. The first approach to solve the optimal control problem is using numerical techniques. Numerical optimization allows incorporation of a vehicle model of high fidelity and generates realistic solutions. Such an optimization scheme provides an ideal platform to study the limit operation of the vehicle, which would not be possible via straightforward simulation. In this work we emphasize the importance of online applicability of the proposed methodologies. This underlines the need for optimal solutions that require little computational cost and are able to incorporate real, unpredictable

  9. Control of the variable speed generator on the Sandia 34-metre vertical axis wind turbine

    NASA Astrophysics Data System (ADS)

    Ralph, Mark E.

    The DOE/Sandia 34-meter VAWT Test Bed is a 500kW variable-speed wind turbine. The turbine is operated between 25 and 38 rpm and has been characterized from a structural and aerodynamic standpoint. A preliminary variable speed control algorithm has been implemented on the Test Bed. This paper describes the initial variable-speed control algorithm developed for the Test Bed and the performance of that algorithm to date. Initial performance comparisons between variable-speed and fixed-speed operation are made as well as some thoughts on the expansion of the operating envelope of the Test Bed.

  10. Control of the variable speed generator on the Sandia 34-metre vertical axis wind turbine

    SciTech Connect

    Ralph, M.E.

    1989-01-01

    The DOE/Sandia 34-metre VAWT Test Bed is a 500kW variable-speed wind turbine. The turbine is operated between 25 and 38 rpm and has been characterized from a structural and aerodynamic stand point. A preliminary variable speed control algorithm has been implemented on the Test Bed. This paper describes the initial variable-speed control algorithm developed for the Test Bed and the performance of that algorithm to date. Initial performance comparisons between variable-speed and fixed-speed operation are made as well as some thoughts on the expansion of the operating envelope of the Test Bed. 7 refs., 4 figs.

  11. Control of a High Speed Flywheel System for Energy Storage in Space Applications

    NASA Technical Reports Server (NTRS)

    Kenny, Barbara H.; Kascak, Peter E.; Jansen, Ralph; Dever, Timothy; Santiago, Walter

    2004-01-01

    A novel control algorithm for the charge and discharge modes of operation of a flywheel energy storage system for space applications is presented. The motor control portion of the algorithm uses sensorless field oriented control with position and speed estimates determined from a signal injection technique at low speeds and a back EMF technique at higher speeds. The charge and discharge portion of the algorithm use command feed-forward and disturbance decoupling, respectively, to achieve fast response with low gains. Simulation and experimental results are presented demonstrating the successful operation of the flywheel control up to the rated speed of 60,000 rpm.

  12. Stability control for high speed tracked unmanned vehicles

    NASA Astrophysics Data System (ADS)

    Pape, Olivier; Morillon, Joel G.; Houbloup, Philippe; Leveque, Stephane; Fialaire, Cecile; Gauthier, Thierry; Ropars, Patrice

    2005-05-01

    The French Military Robotic Study Program (introduced in Aerosense 2003), sponsored by the French Defense Procurement Agency and managed by Thales as the prime contractor, focuses on about 15 robotic themes which can provide an immediate "operational add-on value". The paper details the "automatic speed adjustment" behavior (named SYR4), developed by Giat Industries Company, which main goal is to secure the teleoperated mobility of high speed tracked vehicles on rough grounds; more precisely, the validated low level behavior continuously adjusts the vehicle speed taking into account the teleperator wish AND the maximum speed that the vehicle can manage safely according to the commanded radius of curvature. The algorithm is based on a realistic physical model of the ground-tracks relation, taking into account many vehicle and ground parameters (such as ground adherence and dynamic specificities of tracked vehicles). It also deals with the teleoperator-machine interface, providing a balanced strategy between both extreme behaviors: a) maximum speed reduction before initiating the commanded curve; b) executing the minimum possible radius without decreasing the commanded speed. The paper presents the results got from the military acceptance tests performed on tracked SYRANO vehicle (French Operational Demonstrator).

  13. The selective use of functional optical variables in the control of forward speed

    NASA Technical Reports Server (NTRS)

    Johnson, Walter W.; Awe, Cynthia A.

    1994-01-01

    Previous work on the perception and control of simulated vehicle speed has examined the contributions of optical flow rate (angular visual speed) and texture, or edge rate (frequency of passing terrain objects or markings) on the perception and control of forward speed. However, these studies have not examined the ability to selectively use edge rate or flow rate. The two studies presented here show that this ability is far greater for pilots than non-pilots, as would be expected since pilots must control vehicular speed over a variety of altitudes where flow rates change independently of forward speed. These studies also show that this ability to selectively use these variables is linked to the visual contextual information about the relative validity (linkage with speed) of the two variables. Subjective judgment data also indicated that awareness of altitude and ground texture density did not mediate ground speed awareness.

  14. Intelligent modified internal model control for speed control of nonlinear uncertain heavy duty vehicles.

    PubMed

    Yadav, Anil Kumar; Gaur, Prerna

    2015-05-01

    The objective of this paper is to control the speed of heavy duty vehicle (HDV) through angular position of throttle valve. Modified internal model control (IMC) schemes with fuzzy supervisor as an adaptive tuning are proposed to control the speed of HDV. Internal model (IM) plays a key role in design of various IMC structures with robust and adaptive features. The motivation to design an IM is to produce nearly stable performance as of the system itself. Clustering algorithm and Hankel approximation based model order reduction techniques are used for the design of suitable IM. The time domain performance specifications such as overshoot, settling time, rise time and integral error performance indices such as the integral of the absolute error and the integral of the square of error are taken into consideration for performance analysis of HDV for various uncertainties. PMID:25563057

  15. Measurement of whole-body vibration exposure from speed control humps

    NASA Astrophysics Data System (ADS)

    Khorshid, E.; Alkalby, F.; Kamal, H.

    2007-07-01

    The main objective of speed control humps is to introduce shocks and high vibration levels when a car passes over them if its speed is higher than the allowable limit. Hump geometry is a major factor in altering the level of these shocks and specifying the speed limit. However, there is no study of the relationship between whole body vibration due to passing over a speed control hump and lower back pain or occupational diseases. In this study, an experimental investigation is conducted to evaluate health risks associated with different geometry speed control humps. Vibration levels and shocks are measured by a seat pad accelerometer placed under the driver's seat to evaluate hazard risks on the human body's lower back. The assessment is based on two standard methods of measuring whole body vibration: the British standard BS 6841 and the new ISO/DIS standard 2631-5. These methods are used to assess the effects of vehicle type, passenger location in the vehicle, vehicle speed, and speed control hump geometry. It was found that circular speed control humps currently installed on many public roads should be modified in order to eliminate hazards. Two newly designed speed humps were proved to be less hazardous than circular speed control humps.

  16. High-Speed Current dq PI Controller for Vector Controlled PMSM Drive

    PubMed Central

    Reaz, Mamun Bin Ibne; Rahman, Labonnah Farzana; Chang, Tae Gyu

    2014-01-01

    High-speed current controller for vector controlled permanent magnet synchronous motor (PMSM) is presented. The controller is developed based on modular design for faster calculation and uses fixed-point proportional-integral (PI) method for improved accuracy. Current dq controller is usually implemented in digital signal processor (DSP) based computer. However, DSP based solutions are reaching their physical limits, which are few microseconds. Besides, digital solutions suffer from high implementation cost. In this research, the overall controller is realizing in field programmable gate array (FPGA). FPGA implementation of the overall controlling algorithm will certainly trim down the execution time significantly to guarantee the steadiness of the motor. Agilent 16821A Logic Analyzer is employed to validate the result of the implemented design in FPGA. Experimental results indicate that the proposed current dq PI controller needs only 50 ns of execution time in 40 MHz clock, which is the lowest computational cycle for the era. PMID:24574913

  17. Speed And Power Control Of An Engine By Modulation Of The Load Torque

    DOEpatents

    Ziph, Benjamin; Strodtman, Scott; Rose, Thomas K

    1999-01-26

    A system and method of speed and power control for an engine in which speed and power of the engine is controlled by modulation of the load torque. The load torque is manipulated in order to cause engine speed, and hence power to be changed. To accomplish such control, the load torque undergoes a temporary excursion in the opposite direction of the desired speed and power change. The engine and the driven equipment will accelerate or decelerate accordingly as the load torque is decreased or increased, relative to the essentially fixed or constant engine torque. As the engine accelerates or decelerates, its power increases or decreases in proportion.

  18. Gravitational search algorithm based tuning of a PI speed controller for an induction motor drive

    NASA Astrophysics Data System (ADS)

    Abd Ali, Jamal; Hannan, M. A.; Mohamed, Azah

    2016-03-01

    Proportional-integral (PI)-controller is very useful for controlling speed and mechanical load variables for the three-phase induction motor (TIM) operation. However, the conventional PI-controller has a very exhaustive trial and error procedure for obtaining it is parameters. In this paper, PI speed controller has been improved in it is design technique to suite TIM by utilizing a gravitational search algorithm (GSA) optimization technique. The mean absolute error (MAE) of the speed response has been used as an objective function. An optimal GSA based PI speed controller (GSA-PI) objective function is also employed to tune and minimize the MAE for developing the performance of the TIM in terms of changes speed and mechanical load. This experiment use space vector pulse width modulation (SVPWM) technique to create pulse width modulation for switching devices for three phase bridge inverter. Results obtained from the GSA-PI speed controller are compared with those obtained through particle swarm optimization (PSO) to validate the developed controller. Then it has been proved that the robustness of the GSA-PI speed controller is far better than that of the1 PSO controller in all tested cases in terms of damping capability and transient response under different mechanical loads and speeds.

  19. Benefits of variable rotor speed in integrated helicopter/engine control

    NASA Technical Reports Server (NTRS)

    Iwata, Takanori; Rock, Stephen M.

    1993-01-01

    Current helicopter flight and propulsion controls are typically designed with the assumption that rotor speed will be held to a constant setpoint. A new flight and propulsion control system using a continuously variable rotor speed command is proposed to improve the maneuverability and agility of helicopter systems. In this new approach, the flight control system generates an optimal variable rotor speed command in addition to conventional control commands in a framework of integrated flight/propulsion control. The benefits (i.e. improved maneuverability and agility) of varying rotor speed during transient maneuvers are demonstrated using a bob-up maneuver as an example. In particular, two types of benefits are identified in different maneuver conditions. One comes from a thrust augmentation, while the other comes from an exchange of rotational and translational energy. In the example, a simple linear dynamic hover model is used with an optimal control design method to generate the optimal rotor speed command.

  20. A utility-connected residential PV system adapted a novel single-phase composite PWM voltage source inverter

    SciTech Connect

    Nonaka, Sakutaro

    1994-12-31

    A Utility-interactive residential PV system adapted a novel single-phase composite PWM voltage source inverter (VSI) is proposed. The proposed system is equipped with PV array, battery storage, and a single-phase VSI, which has a new circuit configuration and PWM method. The VSI circuit consists of the normal single-phase bridge circuit and an additional arm. The two auxiliary self-turn-off devices for the arm adopt to a composite PWM control, which contributes to reduce the ripple in the AC output current. Also, the VSI has a LC series resonance circuit tuned to twice the utility frequency connected in parallel with the smoothing capacitor. The series resonance circuit absorbs the double-frequency AC components included in the DC pulsed current. Consequently, the smoothing capacitor is drastically reduced. It was found with the computer simulation and the experiment that the waveform of AC output current shows an ideal sine wave.

  1. Optimal V/f control of super high-speed PMSM and its application

    NASA Astrophysics Data System (ADS)

    Bian, Chunyuan; Ren, Shuangyan; Yan, Shijie; Man, Yongkui; Wang, Zhiqiang

    2006-11-01

    Due to the features such as high efficiency, small volume and high power density, super high-speed permanent magnet synchronous motor (PMSM) are becoming attractive in many fields such as high-speed micro-turbine generators, centrifugal compressors and pumps. V/f control is flexible and easy to be realized, moreover, voltage utilization ratio of SVPWM modulation is high, so the plan combined with V/f control and SVPWM modulation can be adopted for PMSM. The effects of the stator resistance and the dead-time on the control are generally neglected in traditional V/f control, which leads to that the low-speed performance is poor and the system is not stable at high speed. Based on considering the effects of stator resistance and dead-time, an optimal V/f control of the super high-speed PMSM is presented. Combined with the optimal V/f control and SVPWM modulation, soft starting and operating experiments for PMSM generator (105Kw, 61000rpm) are successfully implemented in the designed system of super high-speed gas micro-turbine based on DSP 320F2407A. The experiment results shows that this optimal V/f control is virtual and feasible for super high-speed PMSM. The proposed scheme provided dynamic stability and high performance of the super high-speed PMSM with an open-loop control.

  2. A solid-state PWM phase-shifter. [Pulse Width Modulation

    SciTech Connect

    Ooi, Boon Teck; Dai, Shu Zu; Galiana, F.D. )

    1993-04-01

    The solid-state, pulse width modulated (PWM) phase-shifter is based on gate-turn-off (GTO) thyristors or other valves with force commutation capabilities. Besides serving the phase-shifter function, it offers regulated control over 3 independent quantities: the real power passing through it and the VARs on both sides to which it is connected. The power transferred can be bidirectional and the VARs can be leading or lagging.

  3. Proposal of Current Control Method for High-Speed AC Motor System

    NASA Astrophysics Data System (ADS)

    Furutani, Shinichi; Satake, Akira

    In this paper, current control method for High-Speed AC Motor System is proposed. In High-Speed driving operation, Current controller tends to lose stability because of dead time caused by computational delay and Electromagnetic coupling included AC Motor Model. The Main purpose of the proposed method is reduction of dead time on current controller. Proposed method based model predictive control and optimizing of start timing. The Effectiveness of proposed method is confirmed by simulation results.

  4. Direct Torque Control System for Permanent Magnet Synchronous Machine with Fuzzy Speed Pi Regulator

    NASA Astrophysics Data System (ADS)

    Nabti, K.; Abed, K.; Benalla, H.

    2008-06-01

    The Permanent Magnet Synchronous Machine (PMSM) speed regulation with a conventional PI regulator reduces the speed control precision, increase the torque fluctuation, and consequentially low performances of the whole system. With utilisation of fuzzy logic method, this paper presents the self adaptation of conventional PI regulator parameters Kp and Ki (proportional and integral coefficients respectively), using to regulate the speed in Direct Torque Control strategy (DTC). The ripples of both torque and flux are reduced remarkable, small overshooting and good dynamic of the speed and torque. Simulation results verify the proposed method validity.

  5. Anti-Windup Algorithm with Priority to Proportinal Control Output of Speed PI Controller for Position Servo System

    NASA Astrophysics Data System (ADS)

    Sazawa, Masaki; Yamada, Takahiro; Ohishi, Kiyoshi; Katsura, Seiichiro

    A robust servo system is important for performance improvement of motion control system in several industry applications. Generally, a high speed positioning servo system consists of robust control systems with integrator, such as PI controller. The industrial servo system always has the limitation for the capacity of actuator and power amplifier. An ordinary industrial position servo system often has the saturation of motor current and motor speed. It is difficult for the high speed positioning servo system to keep the robust position control against the saturation of motor current and motor speed. Because, an ordinary position servo system has the complicated control structure with many control loops. Hence, it sometimes has the large overshoot and the oscillated response by the limitation of motor current and motor speed. In order to overcome this problem, this paper proposes a new robust high speed positioning servo system considering the saturation of torque current and motor speed. The experimental results show that the proposed robust high speed positioning servo system the quick and stable position response for the saturation of motor current and motor speed.

  6. Speed control device for a heavy duty shaft. [solar sails for spacecraft propulsion

    NASA Technical Reports Server (NTRS)

    Ford, A. G. (Inventor)

    1980-01-01

    A speed control device is characterized by a reference speed shaft spatially related to a heavy duty shaft, a drive train for driving the reference speed shaft at a constant angular velocity, a drive train for driving the heavy duty shaft at a variable angular velocity and a speed control assembly for continuously comparing the angular velocity of the heavy duty shaft with the angular velocity of the reference speed shaft. A brake assembly is connected to the heavy duty shaft and is adapted to respond to errors in the angular velocity of the heavy duty shaft in order to reduce the angular velocity of the heavy duty shaft to that of the reference speed shaft.

  7. Wind tunnel experiments to prove a hydraulic passive torque control concept for variable speed wind turbines

    NASA Astrophysics Data System (ADS)

    Diepeveen, N. F. B.; Jarquin-Laguna, A.

    2014-12-01

    In this paper the results are presented of experiments to prove an innovative concept for passive torque control of variable speed wind turbines using fluid power technology. It is demonstrated that by correctly configuring the hydraulic drive train, the wind turbine rotor operates at or near maximum aerodynamic efficiency for below rated wind speeds. The experiments with a small horizontal-axis wind turbine rotor, coupled to a hydraulic circuit, were conducted at the Open Jet Facility of the Delft University of Technology. In theory, the placement of a nozzle at the end of the hydraulic circuit causes the pressure and hence the rotor torque to increase quadratically with flow speed and hence rotation speed. The rotor torque is limited by a pressure relief valve. Results from the experiments proved the functionality of this passive speed control concept. By selecting the correct nozzle outlet area the rotor operates at or near the optimum tip speed ratio.

  8. Attitude Control for an Aero-Vehicle Using Vector Thrusting and Variable Speed Control Moment Gyros

    NASA Technical Reports Server (NTRS)

    Shin, Jong-Yeob; Lim, K. B.; Moerder, D. D.

    2005-01-01

    Stabilization of passively unstable thrust-levitated vehicles can require significant control inputs. Although thrust vectoring is a straightforward choice for realizing these inputs, this may lead to difficulties discussed in the paper. This paper examines supplementing thrust vectoring with Variable-Speed Control Moment Gyroscopes (VSCMGs). The paper describes how to allocate VSCMGs and the vectored thrust mechanism for attitude stabilization in frequency domain and also shows trade-off between vectored thrust and VSCMGs. Using an H2 control synthesis methodology in LMI optimization, a feedback control law is designed for a thrust-levitated research vehicle and is simulated with the full nonlinear model. It is demonstrated that VSCMGs can reduce the use of vectored thrust variation for stabilizing the hovering platform in the presence of strong wind gusts.

  9. Maneuver and vibration control of flexible manipulators using variable-speed control moment gyros

    NASA Astrophysics Data System (ADS)

    Hu, Quan; Zhang, Jingrui

    2015-08-01

    In this paper, the variable-speed control moment gyros (VS-CMGs) are adopted as actuators for vibration suppression of space flexible manipulators. They are directly mounted on the flexible links of the manipulator. Such system can be viewed as a flexible multibody system in chain topology actuated by both joint motors and VS-CMGs. We first develop a general approach for establishing the system equations of motion through Kane's method. Then, two controllers are designed for trajectory tracking and vibration suppression: one is an inverse dynamics control, whereas the other is based on the singular perturbation method. The proposed two control strategies are applied to a free-flying platform with a flexible manipulator. Sample numerical results show that the VS-CMGs can significantly suppress the induced vibration of the flexible links during the large angle maneuver.

  10. Direct Space Vector PWM Strategy for Matrix Converters with Reduced Number of Switching Transitions

    NASA Astrophysics Data System (ADS)

    Tadano, Yugo; Hamada, Shizunori; Urushibata, Shota; Nomura, Masakatsu; Sato, Yukihiko; Ishida, Muneaki

    This paper proposes a novel “Direct Space Vector PWM (Direct SVPWM)” strategy based on the direct AC/AC conversion approach for three-phase to three-phase matrix converters. This method allows the sine input and sine output waveforms as a major premise, and gives top priority to the improvement of the output control performance in motor drive applications, for instance, provides maximum riding comfort for an elevator, etc. Output voltage harmonics, switching losses, and common-mode voltage can be reduced across the entire voltage region. In addition, the switching count can be reduced even further by fully utilizing the output current detection value. Direct space vectors are first defined, and the selection method of space vectors is described. Next, the PWM duty calculation technique is explained. Finally, the validity of the proposed method is proven from the comparison with the conventional virtual indirect method based on the experimental and analysis results.

  11. A Motor Speed Servo System Based on the Dual Loop PLL

    NASA Astrophysics Data System (ADS)

    Machida, Hidekazu; Kambara, Michinobu; Tanaka, Kouta; Kobayashi, Fuminori

    PLL-MSC (Phase Locked Loop Motor Speed Control) systems can completely reject speed error and steady-state phase error for constant-speed input signals. However, it is not usually applied to systems with inputs including acceleration, because they have poor tracking speed and strange pull-in behavior. In the field of radio communication, “dual-loop PLL” is very effective for such signals. It can not only enable high-speed tracking, but also cancel phase error. In the digital implementation of the PLL-MSC, it can achive easily by inserting loop filters into both feed back paths, and employed a special adder in PWM to implement loop addition for the two phase detector outputs. The scheme was implemented by programming an FPGA, and satisfiable results were obtained.

  12. Load speed regulation in compliant mechanical transmission systems using feedback and feedforward control actions.

    PubMed

    Raul, P R; Dwivedula, R V; Pagilla, P R

    2016-07-01

    The problem of controlling the load speed of a mechanical transmission system consisting of a belt-pulley and gear-pair is considered. The system is modeled as two inertia (motor and load) connected by a compliant transmission. If the transmission is assumed to be rigid, then using either the motor or load speed feedback provides the same result. However, with transmission compliance, due to belts or long shafts, the stability characteristics and performance of the closed-loop system are quite different when either motor or load speed feedback is employed. We investigate motor and load speed feedback schemes by utilizing the singular perturbation method. We propose and discuss a control scheme that utilizes both motor and load speed feedback, and design an adaptive feedforward action to reject load torque disturbances. The control algorithms are implemented on an experimental platform that is typically used in roll-to-roll manufacturing and results are shown and discussed. PMID:27126600

  13. Analysis of Single Phase PWM Rectifier for Different Applications

    NASA Astrophysics Data System (ADS)

    Mitra, Arkendu; Chowdhuri, Sumana

    2016-06-01

    This research work investigates the various applications of a PWM rectifier based on its input power factor. Most of the cases, the papers describe the operation of the rectifier used for unity power factor (UPF) operation. Beside this mode of operation, this paper compiles the application of the rectifier as STATCOM also, where the rectifier deals only with reactive power exchange. In this work, the controller is implemented by inserting a loop for reference input of phase angle which will be compared with the actual one, so that user can operate the rectifier at any power factor. Some basic formulae are derived for the input current, active power and reactive power based on which the control circuit is to be designed. Here two Proportional-Integral (PI) controllers are used. A brief description of tuning these two PI controllers is incorporated in this paper. Also some calculations are given to determine the harmonic factors of the input line current from which it is found that the rectifier when operated in each mode operation, the order of the harmonics are very low.

  14. Estimator Based Controller for High Speed Flywheel Magnetic Bearing System

    NASA Technical Reports Server (NTRS)

    Dever, Timothy P.; Brown, Gerald V.; Jansen, Ralph H.

    2002-01-01

    A flywheel system and its operator interface are described. Measurements of magnetic bearing negative stiffness are performed. Two digital magnetic bearing control algorithms (PD and estimator based) are defined and their implementations are described. Tuning of each controller is discussed. Comparison of the two controllers' stability, damping noise, and operating current are described. Results describing the superiority of the estimator-based controller are presented and discussed.

  15. 2-SPEED, a single-gimbal control moment gyro attitude control system.

    NASA Technical Reports Server (NTRS)

    Crenshaw, J. W.

    1973-01-01

    In 2-SPEED (Two Scissored Pair Ensemble, Explicit Distribution) four single-gimbal control moment gyros (SGCMGs) configured into two scissored pairs are combined with an explicit distribution of angular momentum between pairs to produce a system relatively insensitive to the singularity problems which have plagued other SGCMG concepts. In this system, the singularity surfaces in momentum space degenerate to discrete curves. Further, the system permits a smooth passage through these remaining singularities with, at worst, a temporary delay while momentum redistribution takes place. Finally, CMG-out operation is possible within the full volume of the reduced momentum envelope.

  16. Speed and efficiency control of an induction motor with input-output linearization

    SciTech Connect

    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.

  17. Integrated High-Speed Torque Control System for a Robotic Joint

    NASA Technical Reports Server (NTRS)

    Davis, Donald R. (Inventor); Radford, Nicolaus A. (Inventor); Permenter, Frank Noble (Inventor); Valvo, Michael C. (Inventor); Askew, R. Scott (Inventor)

    2013-01-01

    A control system for achieving high-speed torque for a joint of a robot includes a printed circuit board assembly (PCBA) having a collocated joint processor and high-speed communication bus. The PCBA may also include a power inverter module (PIM) and local sensor conditioning electronics (SCE) for processing sensor data from one or more motor position sensors. Torque control of a motor of the joint is provided via the PCBA as a high-speed torque loop. Each joint processor may be embedded within or collocated with the robotic joint being controlled. Collocation of the joint processor, PIM, and high-speed bus may increase noise immunity of the control system, and the localized processing of sensor data from the joint motor at the joint level may minimize bus cabling to and from each control node. The joint processor may include a field programmable gate array (FPGA).

  18. Measuring Ability, Speed, or Both? Challenges, Psychometric Solutions, and What Can Be Gained From Experimental Control

    PubMed Central

    Goldhammer, Frank

    2015-01-01

    The main challenge of ability tests relates to the difficulty of items, whereas speed tests demand that test takers complete very easy items quickly. This article proposes a conceptual framework to represent how performance depends on both between-person differences in speed and ability and the speed-ability compromise within persons. Related measurement challenges and psychometric models that have been proposed to deal with the challenges are discussed. It is argued that addressing individual differences in the speed-ability trade-off requires the control of item response times. In this way, response behavior can be captured exclusively with the response variable remedying problems in traditional measurement approaches. PMID:26807063

  19. Fuzzy logic based intelligent control of a variable speed cage machine wind generation system

    SciTech Connect

    Simoes, M.G.; Bose, B.K.; Spiegel, R.J.

    1997-01-01

    The paper describes a variable speed wind generation system where fuzzy logic principles are used for efficiency optimization and performance enhancement control. A squirrel cage induction generator feeds the power to a double-sided pulse width modulated converter system which pumps power to a utility grid or can supply to an autonomous system. The generation system has fuzzy logic control with vector control in the inner loops. A fuzzy controller tracks the generator speed with the wind velocity to extract the maximum power. A second fuzzy controller programs the machine flux for light load efficiency improvement, and a third fuzzy controller gives robust speed control against wind gust and turbine oscillatory torque. The complete control system has been developed, analyzed, and validated by simulation study. Performances have then been evaluated in detail.

  20. Functional integration of vertical flight path and speed control using energy principles

    NASA Technical Reports Server (NTRS)

    Lambregts, A. A.

    1984-01-01

    A generalized automatic flight control system was developed which integrates all longitudinal flight path and speed control functions previously provided by a pitch autopilot and autothrottle. In this design, a net thrust command is computed based on total energy demand arising from both flight path and speed targets. The elevator command is computed based on the energy distribution error between flight path and speed. The engine control is configured to produce the commanded net thrust. The design incorporates control strategies and hierarchy to deal systematically and effectively with all aircraft operational requirements, control nonlinearities, and performance limits. Consistent decoupled maneuver control is achieved for all modes and flight conditions without outer loop gain schedules, control law submodes, or control function duplication.

  1. Comprehensive analysis of the carbon impacts of vehicle intelligent speed control

    NASA Astrophysics Data System (ADS)

    Carslaw, David C.; Goodman, Paul S.; Lai, Frank C. H.; Carsten, Oliver M. J.

    2010-07-01

    In recent years sophisticated technologies have been developed to control vehicle speed based on the type of road the vehicle is driven on using Global Positioning Systems and in-car technology that can alter the speed of the vehicle. While reducing the speed of road vehicles is primarily of interest from a safety perspective, vehicle speed is also an important determinant of vehicle emissions and thus these technologies can be expected to have impacts on a range of exhaust emissions. This work analyses the results from a very large, comprehensive field trial that used 20 instrumented vehicles with and without speed control driven almost 500,000 km measuring vehicle speed at 10 Hz. We develop individual vehicle modal emissions models for CO 2 for 30 Euro III and Euro IV cars at a 1-Hz time resolution. Generalized Additive Models were used to describe how emissions from individual vehicles vary depending on their driving conditions, taking account of variable interactions and time-lag effects. We quantify the impact that vehicle speed control has on-vehicle emissions of CO 2 by road type, fuel type and driver behaviour. Savings in CO 2 of ≈6% were found on average for motorway-type roads when mandatory speed control was used compared with base case conditions. For most other types of road, speed control has very little effect on emissions of CO 2 and in some cases can result in increased emissions for low-speed limit urban roads. We also find that there is on average a 20% difference in CO 2 emission between the lowest and highest emitting driver, which highlights the importance of driver behaviour in general as a means of reducing emissions of CO 2.

  2. Scale-Free Correlations, Influential Neighbours and Speed Control in Flocks of Birds

    NASA Astrophysics Data System (ADS)

    Hemelrijk, Charlotte K.; Hildenbrandt, Hanno

    2015-02-01

    Coordination of birds in large flocks is amazing, especially, since individual birds only interact with a few neighbors (the so-called `influential neighbours'). Yet, empirical data show that fluctuations of velocity and speed of different birds are correlated beyond the influential neighbours and are correlated over a larger distance in a larger flock. This correlation between the correlation length of velocity or speed and flock size was found to be linear, called a scale-free correlation. It depends on the way individuals interact in the flock, for instance, on the number of influential neighbours and speed control. It is unknown however, how exactly the number of influential neighbours affects this scale-free correlation. Recent empirical data show that different degrees of control of speed affect the scale-free correlation for speed fluctuations. Theoretically, based on statistical mechanics, it is predicted that at very high speed control, the correlation is no longer scale-free but saturates at a certain correlation length and this hampers coordination in flocks. We study these issues in a model, called StarDisplay, because its behavioural rules are biologically inspired and many of its flocking patterns resemble empirical data. Our results show that the correlation length of fluctuations of velocity as well as speed correlate with flock size in a scale-free manner. A higher number of influential neighbours causes a diminishing increase of the slope of the scale-free correlation with velocity, resulting thus in flocks that coordinate more uniformly. Similar to recent empirical data higher speed control reduces the correlation length of speed fluctuations in our model. As predicted theoretically, at very high speed control the model generates a non-scale free correlation, and although there are still flocks, they are in the process of disintegrating.

  3. A high-speed GaAs MESFET optical controller

    NASA Technical Reports Server (NTRS)

    Claspy, P. C.; Bhasin, K. B.; Richard, M.; Bendett, M.; Gustafson, G.

    1989-01-01

    Optical interconnects are being considered for control signal distribution in phased array antennas. A packaged hybrid GaAs optical controller with a 1:16 demultiplexed output that is suitable for this application is described. The controller, which was fabricated using enhancement/depletion mode MESFET technology, operates at demultiplexer-limited input data rates up to 305 Mb/s and requires less than 200 microW optical input power.

  4. Rotational speed control of Na +-driven flagellar motor by dual pipettes.

    PubMed

    Nogawa, Kousuke; Kojima, Masaru; Nakajima, Masahiro; Kojima, Seiji; Homma, Michio; Fukuda, Toshio

    2009-12-01

    Single cell analysis has attracted much attention to reveal the detailed and localized biological information. Local environmental control technique is desired to analyze the detailed and localized properties of single cells. In this paper, we propose the local environmental control system with nano/micro dual pipettes to control the local reagent concentration dynamically and arbitrarily. Local environmental control by dual pipettes is applied to the rotational speed control of bacterial flagellar motor, which is a rotary molecular machine. We demonstrate quick response and iterative rotational speed control of Na (+)-driven flagellar motor in both accelerating and relaxing directions by switching the local spout between Na (+)-containing and Na (+) -free solutions with dual pipettes. It is shown that the rotational speed might be controllable by changing the spouting velocity of Na (+)-containing solution with multiplying the applied dc voltage. PMID:19887330

  5. Servo control system for friction drive with ultra-low speed and high accuracy

    NASA Astrophysics Data System (ADS)

    Yang, Shihai; Zhang, Zhenchao

    2008-07-01

    Due to its high accuracy and good performance at low speed, friction drive is widely used in turntable and large astronomical telescopes such as LAMOST and Keck. Especially, friction drives are implemented on the axes of azimuth, altitude and field rotation in LAMOST telescope. This paper describes the study on servo control system for friction drive with ultra-low speed and high accuracy. The principle, constitution, control algorithm and realization of servo system based on friction drive are analyzed and explored.

  6. An interdisciplinary school project using a Nintendo Wii controller for measuring car speed

    NASA Astrophysics Data System (ADS)

    Hansen, Nils Kristian; Mitchell, James Robert

    2013-03-01

    This work examines the feasibility of employing a Nintendo Wii game controller for measuring car speed in an interdisciplinary school project. It discusses the physical characteristics of the controller and of vehicle headlights. It suggests how an experiment may be linked to topics in mathematics, statistics, physics and computer science. An algorithm for calculating speed from repeated recordings of car headlights is provided. Finally the results of repeated experiments with an approaching car are provided.

  7. Improvement of speed control performance using PID type neurocontroller in an electric vehicle system

    SciTech Connect

    Matsumura, S.; Omatu, S.; Higasa, H.

    1994-12-31

    In order to develop an efficient driving system for electric vehicle (EV), a testing system using motors has been built to simulate the driving performance of EVs. In the testing system, the PID (Proportional Integral Derivative) controller is used to control rotating speed of motor when the EV drives. In this paper, in order to improve the performance of speed control, a neural network is applied to tuning parameters of PID controller. It is shown, through experiments that a neural network can reduce output error effectively while the PID controller parameters are being tuned online. 6 refs.

  8. Solid state circuit controls direction, speed, and braking of dc motor

    NASA Technical Reports Server (NTRS)

    Hanna, M. F.

    1966-01-01

    Full-wave bridge rectifier circuit controls the direction, speed, and braking of a dc motor. Gating in the circuit of Silicon Controlled Rectifiers /SCRS/ controls output polarity and braking is provided by an SCR that is gated to short circuit the reverse voltage generated by reversal of motor rotation.

  9. Regardless-of-Speed Superconducting LSM Controlled-Repulsive MAGLEV Vehicle

    NASA Technical Reports Server (NTRS)

    Yoshida, Kinjiro; Egashira, Tatsuya; Hirai, Ryuichi

    1996-01-01

    This paper proposes a new repulsive Maglev vehicle which a superconducting linear synchronous motor (LSM) can levitate and propel simultaneously, independently of the vehicle speeds. The combined levitation and propulsion control is carried out by controlling mechanical-load angle and armature-current. Dynamic simulations show successful operations with good ride-quality by using a compact control method proposed here.

  10. Hi-speed versatile serial crate controller for CAMAC

    SciTech Connect

    Horelick, D.

    1984-10-01

    A serial crate controller, primarily for use in the SLC CAMAC control system, has been designed, and has been in use for about 2 years. The design supports a party line approach, with up to 16 crates on a single twisted pair for data transfers, plus another pair for prompt L response. The bit rate is 5 megabits/s, and complete transaction times of about 10 ..mu..s are achieved for 16-bit data transfers over cables up to 1000 feet long. One of the primary objects of the design was simplicity - there are approximately 60 chips in the two-board unit.