General Electric Company

General Electric Corporation Gmbh

Bimal K Bose

Paul M Espelage

John S Sicko

Franz C Zach

Paul Michael Szczesny

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.

Induction motor drive system

A start-up control for a switched reluctance motor employs an encloder for generating a rotor position information signal for each stator phase and a start-up signal processor. The processor receives the rotor position information signals and processes them in accordance with a direction command. To initiate forward rotation, the information signals are complemented; to initiate reverse rotation, the information signals for adjacent phases are AND-coupled.

Start-up control for switched reluctance motor

A programmable, closed-loop four quadrant control system for a switched reluctance motor employs feedback control, angle control and current control. The feedback control can be implemented with a speed feedback loop and/or a torque feedback loop. The angle control digitally synchronizes stator phase current pulses with rotor position, and the current control acts as a chopping or bang-bang controller to limit magnitude of the stator phase current pulses.

Control system for switched reluctance motor

A microcomputer based method for adjusting feedback loop gains ensures a fast, predetermined response of an induction motor drive system. A pre-computed look-up table contains gain values to be loaded into feedback regulators, the gain values corresponding to each operating point of the induction motor having the values necessary to keep the poles of the closed loop system substantially constant.

Method of real time operating point identification and pole adjustment

A microcomputer for use with a direct current machine drive system processes machine drive system currents and voltages to compute real time machine efficiency. From real time machine efficiency, the microcomputer determines optimum, that is to say, desired machine armature current and optimum machine air gap flux. Machine armature current and field current are regulated, respectively, by controlling machine armature voltage responsive to the difference in magnitude between optimum armature current and actual armature current, and by controlling machine field voltage responsive to the difference in magnitude between optimum machine air gap flux and actual machine armature flux, respectively, to assure machine operation at maximum efficiency irrespective of machine load conditions.

Microprocessor-based control apparatus for a direct current machine

A microprocessor based pulse-width modulated variable speed drive control system providing optimal switching angles based on minimizing r.m.s. current ripple. In addition, a closed loop double deadband control interacts with the optimal switching angles to insure close following of a desired function of a specified variable to be controlled.

Method for providing adaptive control of variable speed AC motor drives

A scalar control supplemented by a decoupler transfer function control is provided to develop frequency and current commands for a current controlled inverter driving an induction machine. The machine torque is controlled by the slip and corresponding torque producing component of stator current. The rotor flux is maintained constant by the flux component of stator current. The total stator current is controlled to hold rotor flux constant with desired torque during steady state conditions and the decoupler compensator varies stator current to maintain rotor flux constant during transient conditions.

Scalar decoupled control for an induction machine using current control

A microcomputer for use with an induction motor drive system processes machine drive system currents, voltages and speed to compute real time machine efficiency. From real time machine efficiency determinations, the microcomputer determines the optimum combination of machine slip frequency and machine air gap flux. The magnitude and frequency of machine stator current are regulated, responsive to the difference in magnitude between optimum machine air gap flux and actual machine air gap flux, and the difference in magnitude between optimum slip frequency and actual slip frequency, respectively, to assure machine steady state operation at maximum efficiency irrespective of machine load conditions.

Microprocessor-based efficiency optimization control for an induction

A scalar control supplemented by a decoupler transfer function control is provided to develop frequency and voltage commands for a voltage controlled inverter driving an induction machine. The machine torque is controlled by the slip and corresponding torque producing component of stator current. The rotor flux is maintained constant by the flux component of stator current. The total stator current is controlled in the outer loop to hold rotor flux constant with desired torque during steady state conditions and the decoupler compensator varies stator voltage to maintain rotor flux constant during transient conditions.

Scalar decoupled control for an induction machine

Regulation of inverter-machine drive system torque and frequency in accordance with operator commands is achieved by the use of an improved, microcomputer-based, control apparatus. At machine frequencies less than a preselected machine frequency, inverter pulse width modulation signal pulses and half cycle polarity signal pulses are supplied by the control apparatus to the inverter to regulate the duration and conduction sequence, respectively, of inverter switching devices in accordance with pulse width modulation signal data computed by equilateral triangulation and stored half cycle polarity signal data. At frequencies above the preselected machine frequency, when computation of inverter pulse width modulation signal data becomes impractical, inverter pulse width modulation signal pulses are synthesized from stored data. This achieves simplification of control hardware and provides improved machine drive system performance.

Microcomputer-based pulse width modulated inverter fed machine drive

Optimal and adaptive control of variable speed AC motor drives

A load-commutated inverter synchronous machine drive system control apparatus comprises at least one microcomputer for determining optimum or desired values for inverter turn-off time, inverter link current and machine air gap flux from machine drive system voltage and currents. Inverter frequency is regulated in accordance with the difference in magnitude between optimum and actual inverter turn-off time to minimize the inverter turn-off angle irrespective of machine frequency, thereby reducing synchronous machine reactive power. Inverter link current and synchronous machine field current are regulated responsive to the difference in magnitude between optimum and actual inverter link current and the difference in magnitude between optimum and actual machine air gap flux, respectively, thereby assuring machine operation at maximum efficiency.

Microcomputer-based control apparatus for a load-commutated inverter

Variable frequency sine waves are converted to constant amplitude cosine waves using the relationship cos .omega.t = .sqroot.1-sin.sup.2 .omega.t. The converter has an almost instantaneous response characteristic and is suitable for a wide frequency range. An application is cosine timing waves for phase controlled converters and cycloconverters.

Frequency insensitive sine wave-to-cosine wave converter

A phase shifter circuit generates cycloconverter reference signals for independently and linearly controlling the real power and input power factor or real and reactive power in either polarity. Using the per phase line voltage as a reference phasor, its amplitude and phase are adjusted by a sine-cosine converter, analog multipliers and summing amplifiers. The phase shifter has an almost instantaneous response and can be controlled by polarity reversing dc control signals.

Phase shifter for controlling the power components and power factor of a

In a system including an input cycloconverter which operates a high frequency resonant tank circuit from a source of low frequency voltage supplied through an input reactor, with or without an output cycloconverter, an input cycloconverter control method and circuit maintains the tank voltage within predetermined limits for both directions of power flow. An additional feature is that the input power factor is programmable. In the voltage control scheme the cycloconverter reference signals vary with the commanded real power and power factor and respectively control the quadrature and direct components of induced cycloconverter voltage.

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Latham, NY, United States of America

Bimal K Bose