motor speed control, consider the use of alternating current (AC) variable frequency drive ... AC variable frequency systems for motor speed control offer ...
NASA Website
... Adjustable Speed Drives (ASD), AC induction motors, AC synchronous motors, centrifugal pumps, and positive displacement pumps were ...
DTIC Science & Technology
The objectives of this program for an improved ac motor controller for battery powered urban electric passenger vehicles were: the design, fabrication, test, evaluation and cost analysis of an engineering model controller for an ac induction motor drive s...
National Technical Information Service (NTIS)
A variable frequency inverter is described for driving an ac induction motor which varies the frequency and voltage to the motor windings in response to varying torque requirements for the motor so that the applied voltage amplitude and frequency are of o...
This paper presents the potential electrical energy efficiency improvements for utilizing alternating current (AC) motors controlled by variable frequency drives (VFD) in place of direct current (DC) motors to drive plastic extrusion machines. A brief background on the extrusion process is ...
E-print Network
A piezoelectric motor has peak performance at a specific frequency f.sub.1 that may vary over a range of frequencies. A drive system is disclosed for operating such a motor at peak performance without feedback. The drive system consists of the motor and an ac source ...
DOE Information Bridge
A prototype system consisting of closely integrated motor, inverter, and transaxle has been built in
NASA Technical Reports Server (NTRS)
An ac motor controller for an induction motor electric vehicle drive system was designed, fabricated, tested, evaluated, and cost analyzed. A vehicle performance analysis was done to establish the vehicle tractive effort-speed requirements. These requirem...
This book is divided into: technology of energy-efficient motors, selection and application of energy-efficient motors, efficiency labeling and verification, power factor, single-phase and synchronous motors, adjustable speed drives, and ac motor control and protection. ...
Energy Citations Database
The paper discusses EPA's research program to develop fuzzy-logic-based energy optimizers for alternating-current (AC) induction motors driven by Adjustable Speed Drives (ASDs). The technical goals of the program are to increase the efficiency of ASD/moto...
Featuring low maintenance requirements and high durability, a direct-digital-controlled AC servo-motor drive system employing a synchronous motor with a permanent-magnetic rotor as well as an induction motor has been developed. This system attains flexibl...
The paper treats of problems relating to the use of different types of motors in autonomous and partially autonomous systems of artificial heart (AH) and auxiliary circulation (AC). Demonstrates that the use of d. c. valve engines (VE) in the drives of the AH and AC systems is highly advisable. Provides the ...
PubMed
The systems described comprise, an automatic microprocessor control of a gearbox drive system, the development of an optimized disc motor design, a partial hydrostatic/electric drive system, a novel 9 phase ac drive, developments in control and power swit...
"The Electric Motors Reference Center, from Machine Design, is designed to provide design engineers with the information they need to specify or purchase electric motors including: AC motors, DC motors, stepper motors and servo motors. The Electric ...
NSDL National Science Digital Library
The motor to be controlled is powered by two energizing circuits. Each of the circuits consists of an A.C. supply connected in series through a current control, such as a thyratron tube, to the motor. One of the energizing circuits provides a driving powe...
The report discusses the development of a fuzzy logic, energy-optimizing controller to improve the efficiency of motor/drive combinations that operate at varying loads and speeds. This energy optimizer is complemented by a sensorless speed controller that maintains motor shaft re...
EPA Science Inventory
This citation summarizes a one-page announcement of technology available for utilization. In a proposed linear magnetic motor and generator, originally developed for cryogenic refrigerators that will be used on future spacecraft, magnetic forces drive a r...
The report discusses the development of a fuzzy logic, energy-optimizing controller to improve the efficiency of motor/drive combinations that operate at varying loads and speeds. his energy optimizer is complemented by a sensorless speed controller that maintains motor shaft rev...
Techniques for energy conservation of reducing losses in ac motor driven systems were compared. The impact on electric utility system as a harmonics, power factor of operation, and Electro Magnetic Interference (EMI) is considered. The techniques evaluated are: (1) the NASA Power Factor Controller, a simple device for reducing power losses in lightly ...
NASA Astrophysics Data System (ADS)
The paper describes briefly the following components of hydrogen-electric power drives: chilled hydrogen gas tank, liquid oxygen tank, fuel cell bank, dc/ac converter, ac drive motors, solid-state ac speed control, dc sputter-ion vacuum pumps, steam turbine generator, and ...
Urban rail propulsion systems in use around the world are carefully discussed in this single-source book. It especially spotlights the status of advanced propulsion systems and their electromagnetic compatability characteristics. It presents actual operating experience of transit systems. Systems covered include: Cam controlled and chopper controlled dc drives, inverter ...
... netic Gun Program under which a compact homopolar generator (HPG) was ... 2 MA HPG that is driven with a variable speed AC-induction motor drive ...
... Specific projects involved the permanent magnet synchronous, switch reluctance, induction and DC motors, power electronics devices, including ...
In the 400 Hz AC systems the probe capacitance is the key factor in producing the necessary 90 degree phase shift for servo motor drive. ...
May 31, 2011 ... Several topologies of AC filters have been implemented and compared. ... trap filter (an inductor and capacitor connected in parallel). ...
... of the dry disk brake on the induction motor is ... ME AC DC), and the DC generator (ME DC ... DC generators can take three basic forms; a commutated ...
This paper presents and discusses techniques for energy conservation by reducing losses in ac motor driven systems, proposed by the technical community in response to surging cost of energy. An important aspect considered is the impact on electric utility systems in terms of harmonics and power factor of operation. The techniques evaluated in this paper ...
This paper reports a novel driving method for an annular plate-type ultrasonic motor. Instead of the direct current/alternating current (DC/AC) converter type driver using conventional electromagnetic transformer, a compact disc-type piezoelectric transformer is used to obtain high voltage output for driving the ...
A shearer-type mineral winning machine has three-phase A.C. Motors on its main body for driving cutting drums and for propelling the machine along a mineral face. The frequency of the A.C. power supplied to the motor which serves to move the machine is varied and controlled in dependence on the ...
A scheme for optimizing the efficiency of an AC motor drive operated in a pulse-width-modulated mode provides that the modulation frequency of the power furnished to the motor is a function of commanded motor torque and is higher at lower torque requirements than at higher torque requirements. ...
DOEpatents
A scheme for optimizing the efficiency of an AC motor drive operated in a pulse-width-modulated mode provides that the modulation frequency of the power furnished to the motor is a function of commanded motor torque and is higher at lower torque requirements than at higher torque requirements.
The bibliography contains citations concerning types and applications of adjustable speed drives (ASD). Uses in heat pumps, fans, compressors, electric motors, boiler feed systems, and power transmission are described. Coverage includes AC-DC motors, induction motors, and brushless electric ...
Converter-fed synchronous-motor drive systems provide optimum control of medium- and high-speed large-capacity AC motors. The article reports on recent technical advances in control methods, large-capacity thyristor converters, and motors, and introduces ...
This article reports that simulations indicate that a 15% longer electric-vehicle driving range is possible with permanent magnet synchronous motor drive systems compared with asynchronous types. The simplified driveline made possible by a permanent magnet design more than offsets its extra cost. A number of ...
This paper discusses the characteristics of the concept and includes discussion of the system constraints, including traction battery constraints, and brief descriptions of the major subsystems being developed. The components discussed include: the system controller, dc to ac inverter, an internal permanent magnet ac motor and a ...
An AC electric motor drive system has been evaluated as a means of engine loading for production engine hot testing. It has been demonstrated that an 80% reduction in test cycle stabilization time is possible when compared with the water brake dynamometer that is commonly used in production engine testing. Hot testing is normally a ...
General-purpose inverters and servo drivers are used for many types of devices, including FA equipment, and the fields of application have been expanding significantly. On the other hand, reducing the motor acoustic noise is one of the major concerns in s...
A 45 to 55% drop in prices makes the variable-speed alternating current motor drives already used in air control systems increasingly popular in industrial process control despite early fears among users that failure of the drives could have a costly negative effect on production. The devices can cut motor energy ...
The cost and feasibility of electric winch drives for underway replenishment highline/spanwire winches is investigated. The winch drives of interest are those using Silicon Controlled Rectifier (SCR) solid state motor controls. Service requirements including performance parameters and reliability/maintainability requirements are ...
The paper discusses EPA's research program to develop fuzzy-logic-based energy optimizers for alternating-current (AC) induction motors driven by Adjustable Speed Drives (ASDs). he technical goals of the program are to increase the efficiency of ASD/motor combinations (especially...
An ac permanent magnet axial flux disc motor was developed to operate with a thyristor load commutated inverter as part of an electric vehicle drive system. The motor was required to deliver 29.8 kW (40 hp) peak and 10.4 kW (14 hp) average with a maximum ...
Strategy for a Synchronous Direct Drive Motor F. Aghili , M. Buehler and J. M. Hollerbach y Centre estimation, synchronous motor. 1 Introduction Direct drive robots whose joints are directly ac- tuated] implemented an adaptive method to con- trol the speed of a permanent-magnet synchronous ...
The MOS-Controlled Thyristor (MCT) is emerging as a powerful switch that combines the better characteristics of existing power devices. A study of switching stresses on an MCT switch under zero voltage resonant switching is presented. The MCT is used as a bidirectional switch in an ac/ac pulse density modulated inverter for induction motor ...
A new battery configuration technique and accompanying control circuitry, termed a Synergetic Battery Pack (SBP), is designed to work with Lithium batteries, and can be used as both an inverter for an electric vehicle AC induction motor drive and as a battery charger. In this paper, the performance of a Synergetic Battery Pack during ...
In this paper, a new single-phase to three-phase converter for low-cost ac motor drive is proposed. The proposed converter employs only six switches and incorporates an active input current shaping feature that results in sinusoidal input current at close to unity power factor. The front-end rectifier in the proposed converter permits ...
A drive train for an electric vehicle includes a traction battery, a power drive circuit, a main contactor for connecting and disconnecting the traction battery and the power drive circuit, a voltage detector across contacts of the main contactor, and a controller for controlling the main contactor to prevent movement of its contacts ...
This patent describes an improved energy efficient control system in conventional air-conditioning and heat pump system. The systems normally including a compressor means, a compressor motor for operating the compressor means, a compressor contactor for turning the compressor motor on and off, an evaporator means, a conditioned air delivery blower fan, a ...
Partial Contents: Ball Screw Nut Direct Driving AC Servo Motor; Ultralow Speed Servo System; Absolute System (Encoder and Driver); Economy-Type Low Noise Inverter DV-651 Series; Industrial Sewing Machine 'Pana-Servo AC' C Series; Circuit-Combination Type ...
The present invention maintains constant torque in an inverter driven AC induction motor during variations in rotor temperature. It is known that the torque output of a given AC induction motor is dependent upon rotor temperature. At rotor temperatures higher than the nominal operating condition the rotor impedance ...
Techniques for energy conservation of reducing losses in ac motor-driven systems proposed by the technical community in response to surging cost of energy are evaluated and compared. Report objectives are to provide better understanding of underlying principles and to evaluate technical and economic viability of these techniques for various applications. ...
In the field of ac spindle drives, the induction motor is widely adopted. Synchronous solutions (reluctance, interior permanent magnets) are often suggested to overcome some drawbacks of the induction motor. This paper compares the different options by considering the machine torque-density and the inverter power ...
The present device is power system for providing an uninterruptible power supply to an external load comprising a flywheel generator, a first motor, a standby generator, and a transfer controller. The flywheel generator is adapted to supply energy to the external load. The first motor is drivingly connected to the flywheel generator. ...
Electric motor efficiency could save the US 100 billion kW of electricity a year. Previous efforts to improve alternating current (AC) motor efficiency focused on improving motor design, bringing efficiency to 95%. But peak efficiency is often only available under a full load, and few motors ...
In this paper, filtering techniques are investigated to reduce the motor terminal overvoltage, ringing and dv/dt in inverter-fed ac motor drive systems where long leads are required. Analysis is presented to show that the distributed LC of a cable and the pulse-width modulated (PWM) inverter switching action lead ...
is considered for use as an AC motor drive. The basic idea is that the capacitor H-bridges supply the reactiveHigh Dynamic Performance Programmed PWM Control of a Multilevel Inverter with Capacitor DC Sources supplied by a capacitor is considered for use as a motor drive. The capacitor ...
It is recognized that wide applications of electric vehicles (EVs) will bring tremendous social, economical and ecological benefits. With the growing interests in electric vehicles, much effort is demanded for the development of efficient, reliable and economical AC drives` for EV propulsion purpose. Both induction motor (IM) ...
Variable structure control systems are characterized and a continuous real-time demonstration of the speed control of a dc motor using a variable structure design is described. A variable structure design for ac drives is also addressed. Problems with var...
The first part of the paper presents the results of measurements on torque and force irregularities of running reaction wheels. Six different, current technology European wheels, both with ball- and magnet bearings, and with d.c. and a.c. drive motors are...
The paper reviews the development of electrical machines of the reluctance type over the past twenty years. Reluctance machines are grouped into two broad categories, viz the AC reluctance machine with magnetically coupled stator phases, and the DC, or sw...
automatic method for tracking the cavity resonance and impedance match would ... ac motor driving an eccentric crank on its shaft to modulate the stub tuner ...
Electric motors are significant users of electricity in the United States. Approximately 66 percent of the total electricity in the U.S. is used by electric motors. Electronic adjustable speed drives (ASDs) can save energy, lower maintenance cost and improve product quality. By providing a variable frequency output to ...
This motor is a permanent magnet type a-c motor with two field windings. As an a-c motor it has a speed of 72 rpm; however, when direct voltage is applied to the field windings, the motor will lock into a magnetic hold position, and if the voltage is then switched, ...
This paper presents a medium-voltage motor drive with a modular multilevel PWM inverter, and focuses on a startup method and its performance. It is formed by six modular arms, each of which consists of a cascaded stack of multiple bidirectional chopper-cells. The frequency of the dominant ac-voltage fluctuation is equal to the ...
Adjustable speed AC drives have become the preferred choice in many industrial applications where controlled speed is required. At the same time, the maturing of the technology and the availability of fast and efficient solid state power semiconductor switches (IGBTs) has resulted in voltage source, PWM controlled inverters becoming a standard ...
A transistorized control circuit including a frequency-determining crystal oscillator feeds a voltage chopper which doubles the 28-v d-c supply and divides the driving frequency is described. The a-c pulsed output then drives a synchronous clock motor. The system measures time intervals from 10 sec to ...
This paper evaluates the performance of a MOS-Controlled Thyristor (MCT) in a practical application. The {ital P}-type MCT is used in an AC Resonant Link Converter (ACRLC) which synthesizes three phase motor line currents from a high frequency AC (20 kHz) input. Based on the principle of discrete pulse modulation, the ACRLC operates as ...
This invention relates to a power supply system having the capability of furnishing to a load sensitive to electrical faults and interruptions, electrical power for prolonged periods of time after a utility or other external power supply source thereto is interrupted. The system comprises a main A.C. generator furnishing A.C. potential at a selected ...
