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Showing papers on "Induction motor published in 1985"


Journal ArticleDOI
Kenichi Iizuka1, Hideo Uzuhashi1, Minoru Kano1, Tsunehiro Endo1, Katsuo Mohri1 
TL;DR: In this article, the motor voltage is chopped by commutator transistors to change the motor speed, and the motor rotor position is determined by the back electromotive force induced in the stator windings.
Abstract: The microcomputer control of a brushless motor without a shaft position sensor is studied. A method which permits the determination of the permanent magnet rotor position by the back electromotive force (EMF) induced in the stator windings and the starting technique which uses the motor as a synchronous motor at standstill are explained. The motor voltage is chopped by commutator transistors to change the motor speed. The control system consists of a 4-b single-chip microcomputer and two quad-comparators.

455 citations


Journal ArticleDOI
TL;DR: In this article, a rotor parameter identification technique for the purpose of updating the control gains of an induction motor vector controller is described, which utilizes the current source nature of a current-regulated PWM inverter by injecting a prescribed negative sequence current perturbation signal.
Abstract: A rotor parameter identification technique for the purpose of updating the control gains of an induction motor vector controller is described. The approach utilizes the current source nature of a current-regulated PWM inverter by injecting a prescribed negative sequence current perturbation signal. The corresponding negative sequence voltage is sensed and decomposed into its d and q components. By injecting the signal at two widely separated frequencies (one perhaps dc), it is shown that the rotor resistance can be uniquely derived. Verification of the validity of the technique is obtained by a full-scale simulation of a vector controlled induction motor drive.

291 citations


Journal ArticleDOI
TL;DR: In this paper, the rotor position was detected by monitoring the winding currents of the rotor rotor in a helicopter or series-resistance drive over the complete speed range of a stepping motor.
Abstract: The paper describes new methods of detecting rotor position in stepping and switched motors, with chopper or series-resistance drives, by monitoring winding currents. In contrast to previous methods of waveform detection, the new techniques are reliable over the complete speed range. It is shown that the most useful indicators of rotor position are: i) current rise times arising from chopping an unexcited phase at low current and ii) the initial rate of current rise as a phase is switched on in a series-resistance drive. Implementation is via simple low-cost electronic circuits and the paper includes discussion of how the techniques can be applied to closed-loop stepping motor control, ministep drives, and optimization of step response.

273 citations


Journal ArticleDOI
TL;DR: In this article, a simple method for minimizing the global system losses is presented based on the adaptive control of the rotor flux in a field-oriented drive system, which is verified using digital simulation.
Abstract: The problems associated with the implementation of an optimal efficiency controller in variable frequency induction motor drives are examined. A simple method for minimizing, on-line, the global system losses is presented. This method is based on the adaptive control of the rotor flux in a field-oriented drive system. The effectiveness of this control strategy is verified using digital simulation.

253 citations


Journal ArticleDOI
TL;DR: In this article, a generalised method of harmonic analysis is proposed to predict the performance of a cage motor with a stator winding fault, for the particular instances of a phase-to-neutral fault and a phaseto-phase fault.
Abstract: The paper outlines a generalised method of harmonic analysis which enables the performance of a cage motor with a stator winding fault to be predicted. The method is verified using experimental measurements made on a ten-pole motor, for the particular instances of a phase-to-neutral fault and a phase-to-phase fault.

197 citations


Journal ArticleDOI
TL;DR: In this paper, different ways of considering the movement in field equations are presented, and the proposed methods and the accuracy of the obtained results are illustrated by simulation examples, where the authors show that the results obtained by these methods are accurate.
Abstract: The different ways of considering the movement in field equations are first presented. Then the proposed methods and the accuracy of the obtained results are illustrated by simulation examples.

167 citations


Journal ArticleDOI
TL;DR: In this article, a doubly salient switched reluctance motor was analyzed for varying excitations at different positions of the rotor and the flux levels through different magnetic paths were obtained, and the variation of inductance with rotor position can be predicted more accurately.
Abstract: This paper describes the application of two-dimensional finite element analysis of a doubly salient switched reluctance motor. The motor has six poles on the stator and four poles on the rotor. The magnetic field patterns are determined for varying excitations at different positions of the rotor. The flux levels through different magnetic paths are obtained. The flux that passes through the rotor and stator core, the flux that flows through the interpolar air gap linking only the excited winding and the flux that links both the excited and the adjacent pole windings are clearly identified. From the results obtained, the variation of inductance with rotor position can be predicted more accurately.

109 citations


Patent
Walter J. Pohl1
20 Sep 1985
TL;DR: In this article, the authors present a self-calibrating compressor motor protection and defrost control system that can be used in a variety of different air conditioner or heat pump models of different sizes and capacities.
Abstract: Disclosed are refrigeration system control systems and methods for compressor motor protection and defrost control. The disclosed systems and methods are generic in the sense that they are self-calibrating and so may be employed in a variety of different air conditioner or heat pump models of different sizes and capacities, without being specifically tailored for a particular model. The disclosed systems and methods sense loading on the compressor and evaporator fan motors, preferably by sensing the voltage across the capacitor-run winding of an AC induction motor and normalizing with respect to line voltage. The self-calibrating capability is implemented by taking advantage of the changing loads as a function of time on both the compressor and fan motors during both normal and abnormal operation of a refrigeration system. In overview, a reference value of motor loading is established for each motor at certain times during an ON cycle. At later times the then-prevailing motor loading is compared to the stored reference in order to provide a basis for control decisions. The ratio of capacitor-run winding voltage to line voltage is an advantageous indicator of motor loading. In one embodiment, a reference ratio of capacitor-run winding voltage to line voltage is established, and at later times is compared to the then-prevailing ratio of capacitor-run winding voltage to line voltage.

96 citations


Journal ArticleDOI
TL;DR: In this paper, a unified theoretical approach for the calculation of the performance of the single-phase capacitor-start permanent-magnet (PM) ac line-start motor is presented, and a common set of reference frame transformations for steady-state, transient and asynchronous performance is also provided, permitting the use of all the theory developed for the balanced polyphase PM motor.
Abstract: A unified theoretical approach is presented for the calculation of the performance of the single-phase capacitor-start permanent-magnet (PM) ac line-start motor. The earlier work of Chang and of Finch and Lawrenson on capacitor reluctance motors is extended. As far as possible, a common set of reference frame transformations for steady-state, transient, and asynchronous performance is also provided, permitting the use of all the theory developed for the analysis of the balanced polyphase PM motor. A new approximate technique is given for estimating the average asynchronous torque/speed curve from computed acceleration curves.

93 citations


Journal ArticleDOI
TL;DR: A computer study to determine various operating quantities of squirrel-cage induction motors as a function of unbalanced voltage and mechanical loading utilizing a new analytical technique will aid in selecting and setting relays to provide protection against voltage unbalance.
Abstract: The results are presented of a computer study to determine various operating quantities of squirrel-cage induction motors as a function of unbalanced voltage and mechanical loading utilizing a new analytical technique. A similar study with the extreme unbalance of single phasing was reported elsewhere. The operating characteristics of various motor protective devices are then superimposed on the motor operating curves to evaluate the effectiveness of the specific relay. The results of this study will aid in selecting and setting relays to provide protection against voltage unbalance and may possibly provide an engineering rationale for the development of future protective devices.

91 citations


Patent
14 Oct 1985
TL;DR: In this article, a waveform generator is used to determine the relative magnitude of motor phase current for every position of the rotor during the period of energization of a motor phase, subject to the waveform pattern established by the generator.
Abstract: A drive system includes a reluctance motor, driving a load. The motor has stator and rotor poles and magnetizing windings for each stator pole. The airgap is small so that saturation occurs during pole overlap, and the poles are constructed so that there is torque overlap between phases as successive phases are energized during rotor rotation. A sensor provides a rotor position input to a reference waveform generator. The output of the generator is determined by rotor position and is applied to a power converter through a current controller. Accordingly the waveform generator establishes a relative magnitude for motor phase current for every position of the rotor during the period of energization of a motor phase. A further input may be applied to the system to determine the absolute magnitude of the phase current, subject to the waveform pattern established by the generator. The rotor poles may be skewed to modify the static torque versus rotor angle characteristic of the motor, the skew being between one-quarter and one-half of rotor pole arcuate extent.

Patent
08 Jul 1985
TL;DR: In this paper, the stator and bearing support are separated from one another by an air gap adjacent at least part of their facing faces by means of an elastic damper, which is used to reduce noise emissions.
Abstract: Electric motor with a substantially cylindrical air gap between the stator and the rotor, the stator being fitted to a bearing support for the rotor shaft bearing. In order to reduce noise emissions, the stator is connected to the bearing support by means of an elastic damper and the stator and bearing support are separated from one another by an air gap adjacent at least part of their facing faces.

Journal ArticleDOI
TL;DR: In this paper, an adaptive power factor controller for three-phase inducti on generators and also for motors is proposed, which senses the reactive current drawn by the machine and accordingly provides the needed reactive power to improve the power factor to as close to unity as possible.
Abstract: An adaptive power factor controllerfor three-phase inducti on generators (and also for motors) is proposed in this paper. The controller senses the reactive current drawn by the machine and accordingly provides the needed reactive power to improve the power factor to as close to unity as possible. The controller is a modular, low-cost, harmonic free device. It does not create any transients in line current. It is designed to eliminate the self-excitation problems associated with induction generators. The controller is tested on an induction generator, which is being used in wind energy and similar applications.

Journal ArticleDOI
TL;DR: In this paper, a simplified method to calculate harmonic currents of an induction motor and optimum PWM switching patterns to minimize the harmonic loss is presented, which is very small under normal operating condition.
Abstract: A simplified method to calculate harmonic currents of an induction motor and optimum PWM switching patterns to minimize the harmonic loss are presented. Neglecting the harmonic iron loss, the harmonic loss of the motor is proportional to the square of the rms current. The waveform of the harmonic current is approximately equal to that of the leakage reactance applied to the same PWM voltage. Its approximation error is very small under normal operating condition. The main results obtained using these approximation are as follows: 1) the optimum PWM patterns of the pulsenumber from seven to 41; 2) how to choose the optimum pattern and calculate it by using a computer; 3) the effect of a resistance of the windings and skin effect of the secondary conductor; and 4) microcomputer PWM optimum voltage control schemes. Comparison with other controls is shown by using experimental and calculating results and confirms the effectiveness of this control scheme.

Journal ArticleDOI
TL;DR: In this article, a generalized induction motor model in the arbitrary reference frame that includes saturation of the magnetizing branch is presented, and the model incorporates the spatially dependent or cross saturation effect.
Abstract: A generalized induction motor model in the arbitrary reference frame that includes saturation of the magnetizing branch is presented. The model incorporates the spatially dependent or cross saturation effect. Steady-state, dynamic, and transient analyses and tests are presented to show the importance saturation has to induction motor dynamics. Comparisons with other simulation approaches show that the proposed model has clear advantages in computational accuracy and efficiency.

Journal ArticleDOI
TL;DR: In this paper, the authors present a design and analysis study for the conceptual design of an economical high-efficiency ac motor based on permanent magnets, and the study results indicate that a motor with ferrite magnets meets the objectives of the program in ratings of up to 25 hp.
Abstract: The design and analysis study for the conceptual design of an economical high-efficiency ac motor based on permanent magnets is summarized. Material considerations, design trade-off options as well as transient and steady-state performance under normal and abnormal conditions have been considered. The baseline comparison is the high-efficiency induction motor. The permanent magnet (PM) motor must fit into the same frame size and surpass the induction motor on a life cost basis that includes 2.5 years of operation at a 50 percent duty cycle. The study results indicate that a motor with ferrite magnets meets the objectives of the program in ratings of up to 25 hp. A 7.5-hp motor design is carried through the conceptual design stage.

Patent
19 Aug 1985
TL;DR: In this article, the rotational speed of an induction motor is estimated based on the detected torque current component and the speed of the motor is controlled such that the estimated speed signal coincides with a speed command signal.
Abstract: In induction motor driven by a voltage-type inverter, the torque current component is determined by detecting a primary current flowing to the induction motor. On the basis of the torque current component determined, the output voltage and frequency of the voltage-type inverter are controlled. Additionally, the rotational speed of the induction motor is estimated on the basis of the detected torque current component and the speed of the induction motor is controlled such that the estimated speed signal coincides with a speed command signal.

Journal ArticleDOI
TL;DR: In this paper, two types of vector control induction motors are discussed: the conventional vector control with high gain current feedback loop, and the decoupling control based on the voltage model of an induction motor with no current feedback.
Abstract: Two types of vector control induction motor are discussed. One is the conventional vector control with high gain current feedback loop, the other is the decoupling control based on the voltage model of an induction motor with no current feedback. Several comparison tests show the superiorities of the decoupling control. The multimicroprocessor-based hardware configuration is presented.

Journal ArticleDOI
TL;DR: In this article, a concept of decoupling control in the strategy of the speed regulation of the squirrel cage induction motor with controlled voltage source is represented, which intends to cancel out the cross terms between the secondary flux and the secondary current.
Abstract: A concept of decoupling control in the strategy of the speed regulation of the squirrel cage induction motor with controlled voltage source is represented. The decoupling control intends to cancel out the cross terms between the secondary flux and the secondary current. Three necessary and sufficient conditions for the decoupling control are offered that correspond to taking into account the effect of the primary impedance in the control strategy. Phase lead compensation with the slip frequency control allows the realization of the decoupling control, which is found to be an extension of both the conventional vector control and the constant volts/hertz control. Numerical and experimental results are also shown.

Patent
Bimal K. Bose1
10 Jul 1985
TL;DR: In this paper, an induction motor is operated under sliding mode control such that the motor shaft position follows a predetermined trajectory, and a sliding mode controller determines the correct torque command which causes the motors shaft position to follow the desired trajectory.
Abstract: An induction motor is operated under sliding mode control such that the motor shaft position follows a predetermined trajectory. The motor drive's improved insensitivity to load disturbances makes it particularly well adapted to servo applications such as robot and machine tool applications. A sliding mode controller determines the correct torque command which causes the motor shaft position to follow the desired trajectory.

Patent
Nobuyoshi Mutoh1, Keijiro Sakai1, Akiteru Ueda1, Akira Ishibashi1, Ikuo Okajima1 
15 Apr 1985
TL;DR: In this paper, a current polarity detector detects positive and negative components of a DC current flowing in the input side of the inverter circuit, and the frequency setting signal is so corrected as to be decreased when only the positive current component flows in excess of one period of the carrier wave signal or increased if only the negative current component flow in the excess of the one period.
Abstract: An AC motor such as an induction motor or a synchronous motor is driven by a PWM inverter circuit. Power switching elements of the inverter circuit are ignited by PWM pulses resulting from comparison of a carrier wave signal with a sine wave modulation signal at a frequency proportional to a frequency setting signal so as to control the inverter circuit. A current polarity detector detects positive and negative components of a DC current flowing in the input side of the inverter circuit. The frequency setting signal is so corrected as to be decreased when only the positive current component flows in excess of one period of the carrier wave signal or increased when only the negative current component flows in excess of the one period.

Patent
29 Nov 1985
TL;DR: In this paper, a sinusoidally weighted pulse width modulated signal is used to switch a pair of solid state power switches on and off in alternation in order to connect the motor alternately across positive and negative power supplies.
Abstract: A substantially perfect single phase sinusoidal shaped voltage waveform may be generated for driving a single phase a-c induction motor by employing a sinusoidally weighted pulse width modulated signal to switch a pair of solid state power switches on and off in alternation in order to connect the motor alternately across positive and negative power supplies. A low pass filter is effectively connected in series with the single phase motor to filter out all of the signal components except the fundamental of the sine wave modulating frequency. In this way, only a sinusoidal voltage is applied to the motor. By making the switching frequency very high relative to the sine wave modulation component, the filter size and cost are minimized and it is unnecessary to correlate or synchronize the sine wave modulation and switching frequencies.

Patent
02 Oct 1985
TL;DR: In this paper, an energy-saving system for feeding an electric induction motor serving as a load, which is operated from a 3-phase voltage power line, and in conjunction with feeding conductors for the motor, is presented.
Abstract: An energy-saving system for feeding an electric induction motor serving as a load, and which is operated from a 3-phase voltage power line, and in conjunction with feeding conductors for the motor includes a power-delivery sub-system operating in a magnetically linear region and coupled to the 3-phase voltage power line for providing variable feeding voltages to the induction motor, a sensing device coupled to the induction motor for generating a signal indicative of the derivatives of active power consumed by the induction motor with respect to the voltage of at least one phase provided to the induction motor, and a control apparatus coupled to the sensing device and to the power-delivery sub-system for regulating at least one of the feeding voltages, so that the derivative of the active power with respect to the voltage of that at least one phase is always substantially zero; thus for a given mechanical power output the power consumption of the induction motor is optimized, while concurrently losses in the feeding conductors are being minimized.

Journal ArticleDOI
01 May 1985
TL;DR: In this paper, a generalised technique for applying harmonic analysis to determine the steady-state performance of a cage induction motor with any stator winding connection and any excitation configuration, is described.
Abstract: A generalised technique for applying harmonic analysis to determine the steady-state performance of a cage induction motor with any stator winding connection and any excitation configuration, is described. Explicit formulas are given for all the impedances required. The method is verified by means of comparison between experimentally measured variations of input power, input current, and electromagnetic torque and those calculated using the technique.

Journal ArticleDOI
TL;DR: A means is provided to compare results for different optimization criteria in order to reach an overall optimum as the best compromise between the results gained from the different optimization methods.
Abstract: Several optimization criteria exist for pulsewidth modulation (PWM) inverter control as applied to ac motor drives. Drive dynamics, i.e., torque and speed ripples, are analyzed and optimized. As a representative example, the PWM inverter control is assumed to have three and five degrees of freedom. These degrees of freedom are realized by so-called switching angles which determine the inverter output voltage waveshape. This voltage is applied to an induction motor. Analysis is executed for a steady-state approximation (using Fourier analysis) as well as for the rigorous fifth-order dynamic equations. The results are compared. The optimal solution for the switching angles as a function of the voltage fundamental is shown. The location of the optima is compared with the efficiency optimal control presented in an earlier paper. A means is provided to compare results for different optimization criteria in order to reach an overall optimum as the best compromise between the results gained from the different optimization methods.

Patent
04 Mar 1985
TL;DR: In this paper, a non-interruptive motor generator power system for generating and supplying to a load of irregular and interruptible A.C. is presented. But the generator is not equipped with a generator generator.
Abstract: A compact, high efficiency non-interruptive motor generator power system for generating and supplying to a load A.C. of a substantially constant frequency and of a substantially constant voltage, the motor thereof being a synchronous A.C. motor energizable from a source of irregular and interruptible A.C. line power, the generator being capable of converting its rotational energy into the A.C. output for many seconds after interruption of the A.C. line power. The power system comprises a high efficiency, synchronous permanent magnet A.C. motor and an A.C. generator coupled to and driven by the motor. Both the motor and generator have a high rotational enertia common rotor wherein an outer cylindrical shell contains motor and generator rotor elements of high permeability soft magnetic material with a surface layer of magnetizable permanent magnetic material, and in each stator is an excitation coil, energizable with A.C., having a pole piece adjacent a layer of permanent magnetic material whereby to magnetize the layer into a selected pattern of north and south magnetic poles. The motor stator is within and encircled by the common rotor and has power windings producing a rotating magnetic field while the generator stator has windings for generating the A.C. power to the load during rotation of the so-magnetized rotor. Both stators also have feedback windings. In the motor stator, the feedback windings generate A.C. of a selected magnitude and phase which is conveyed by a resonant circuit to the excitation coil and there combined so as to provide energization thereof by A.C. of such strength and phase condition as to magnetize the layer of permanent magnetic material into the selected pattern. In the generator, the A.C. generated in the feedback windings is conveyed by an electrical circuit to the generator excitation coil which will essentially neutralize any A.C. induced therein by the magnetic field as the speed changes through the synchronous speed.

Patent
12 Dec 1985
TL;DR: In this paper, a high speed induction motor consisting of a stator and a rotor coaxially positioned within the stator, and mounted in a suitable frame having a water cooled jacket is described.
Abstract: A high speed induction motor comprising a stator and a rotor coaxially positioned within the stator, and mounted in a suitable frame having a water cooled jacket. The stator includes a multiphase winding 16 on a laminated core 18, and having stainless steel end plates 24. Cooling coils 30 are around the end turn portions of the windings, and layers of insulation 28 are between the windings and the cooling coils. The rotor 12 has a core section 37 and an integral shaft 38. A plurality of elongated conductor bars 40 fit tightly into semiclosed elongated slots 42 in the rotor core 37, the slots and bars preferably having a wedge shaped cross section, and having a narrow neck portion adjacent the outer periphery of the rotor core, forming rotor teeth 54 between adjacent conductor bars. Copper end rings 68 are provided at opposite ends of the rotor core, with reduced opposite end portions 76 of the conductor bars received and brazed within spaced slots 70 around the periphery of the end rings. The copper end rings are spaced from the ends of the rotor core by non-magnetic spacers 78 and retained by titanium end caps.

Patent
21 May 1985
TL;DR: In this paper, a control circuit is provided for automatically re-applying starting torque to a single phase AC induction motor by reconnecting the auxiliary or starting winding (2) to the AC power source (3) if the motor has not accelerated to a given cut-out speed, or otherwise begins to stall.
Abstract: A control circuit (10) is provided for automatically re-applying starting torque to a single phase AC induction motor by reconnecting the auxiliary or starting winding (2) to the AC power source (3) if the motor has not accelerated to a given cut-out speed, or otherwise begins to stall. Multiple reconnections of the auxiliary winding (2) are automatically provided as needed, without external intervention, to provide multiple bumping action. The auxiliary winding (2) is connected to the AC source (3) during initial energization of the motor, and is disconnected after a given starting interval. Induced voltage in the auxiliary winding (2) is sensed and compared against a reference voltage (17) for reconnecting the auxiliary winding (2) when the sensed auxiliary winding voltage drops below a given value relative to the reference voltage. The disconnecting, sensing and reconnecting functions are accomplished with a minimum number of components.

Patent
27 Feb 1985
TL;DR: In this paper, a speed control apparatus for an elevator in which a temperature detector for detecting the ambient temperature of an induction motor is disposed, and an arithmetic unit employing a microcomputer is additionally furnished with the function of evaluating the component of temperature rise of a rotor and obtaining the resistance value of the rotor, to evaluate the optimum instantaneous current command by the use of the temperature-compensated resistance value, whereby the overvoltage and insufficient torque of the induction motor can be obviated.
Abstract: A speed control apparatus for an elevator in which a temperature detector for detecting the ambient temperature of an induction motor is disposed, and an arithmetic unit employing a microcomputer is additionally furnished with the function of evaluating the component of temperature rise of a rotor and obtaining the resistance value of the rotor by the use of this component of temperature rise and the temperature detection signal of the temperature detector, to evaluate the optimum instantaneous current command by the use of the temperature-compensated resistance value, whereby the overvoltage and the insufficient torque of the induction motor can be obviated.

Patent
19 Apr 1985
TL;DR: In this paper, a double delta run winding with the phase windings connected in parallel and a double-delta start winding is defined. But the double delta start wound coils are paired and selectively connected to each other by speed responsive switches.
Abstract: The alternating current motor stator (2) of a polyphase motor has each coil (9) wound of at least two separate conductors (10, 11 ). The terminal ends (12, 13, 14, 15) of each conductor is encoded for separate circuit interconnection to other conductors of other coils of the motor stator. The coils are inserted into the stator with a single coil side per slot and appears as a conventional chain winding. The bi-filar wound coils have the encoded ends connected to obtain the benefits of double delta winding connections. The coils are paired and selectively connected to each other by speed responsive switches to define a double delta run winding with the phase windings connected in parallel and a double-delta start winding.