General Electric Company

James W Sember

Loren H Walker

Herbert W Weiss

David G Porter

Stephen E Williams

Donald S Berkowitz

Stephen R MacMinn

Leland C Tupper

Thomas Walker

A method of controlling a switched reluctance motor during high speed operation in an operational range when the counter electromotive force exceeds the available DC source voltage and, therefore, the maximum desired converter current cannot be obtained, establishes torque control in a feedforward manner by controlling current pulse position.

Control system for high speed switched reluctance motor

A method for operating a multi-phase switched reluctance motor is a generator mode includes gating switches connected in series with selected ones of the phase windings of the motor into conduction to establish current flow in a selected one of the windings. The switches are thereafter disabled and current is forced to commutate into flyback diodes whereby the current is returned to an associated DC bus. The instant at which the conducting switches are gated out of conduction is selected or measured in angular displacement between an associated stator pole and a corresponding rotor pole by establishing a preselected magnitude of current such that when the current in the winding reaches that magnitude, the switches are disabled. The voltage at the DC bus is regulated during generator mode operation by adjusting the phase angle measured between a stator pole and a corresponding rotor pole at which the switches are gated into conduction. The voltage is alternatively regulated at the DC bus by adjusting the phase angle at which the switches are disabled if the generated current does not reach the preselected magnitude. Overcurrent protection is included to reduce the turn-on angle if the current in the DC bus exceeds another preselected magnitude.

Control system for switched reluctance motor operating as a power

A method and apparatus for improving the operation of a switched reluctance motor at low speed incorporates an advance angle regulator which regulates the firing angle of current pulses to the switched reluctance motor so that over a wide range of speeds and levels for direct current source voltages, the winding current reaches a commanded set point at a commanded angle. The advance angle regulator may comprise a closed loop regulator which includes apparatus for detecting the actual angular position at which motor current reaches a commanded level and adjusts the turn-on angle to shift the angle at which current reaches its desired level to a desired angle. The regulator incorporates a feedforward portion and an integral portion. The feedforward portion is utilized primarily to accommodate situations in which there is no current feedback. The integral portion provides the primary regulation when current is regulated to its desired value. The regulator causes the torque versus current command to have a transfer function which does not depend upon speed or DC source voltage over a wide range of speed, voltage and torque.

Control system for low speed switched reluctance motor

A method of developing a signal representative of the instantaneous frequency of an alternating current signal encompasses first determining the apparent frequency of the signal at the ends of sampling periods (e.g., half cycles). From successively derived apparent frequencies the rate of change in frequency is calculated. The actual frequency signal is then generated as a function of the apparent frequency and the rate of change. In a specific implementation, the method is employed to develop a signal representative of the rotational speed of a motor.

Frequency measurement system

A system for controlling the operation of an alternating current induction motor having windings supplied by electrical power from the polyphase alternating current source includes a load commutated inverter circuit which is connected between the power source and the induction motor for furnishing electrical power to the motor. Controllers responsive to a command signal and a feedback signal indicative of motor operating parameters control the operation of said load commutated inverter circuit. There is further provided a fixed capacitor circuit connected between the windings of the motor for supplying reactive volt amperes (VARs) to said load commutated inverter circuit and said motor. Finally, there is provided a variable VAR generator connected between the motor windings for supplying VARs to said load commutated inverter circuit and said motor in response to the output of a third feedback control path which is also responsive to a command signal and prescribed operating parameter(s) of said load and/or said commutated inverter.

Flux control for induction motor drive using load commutated inverter

Excitation current control for induction motor drive using load

A variable aspect arc chute comprises a stack of pivotally-mounted plates which are held in electrical contact along one edge thereof by means of a bias spring or other device. The arc chute may be employed in a circuit interrupter, connected in parallel arrangement across main contacts which the present invention protects from excessive arcing damage.

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Roanoke, VA, United States of America

James W Sember