Westinghouse Electric Corporation

Aeg Westinghouse Transportation Systems

David J Shero

Habib Dadpey

Paul J Merlino

Lalan G Miller

C Scott Magee

An AC induction motor control apparatus includes the determination of the motor torque by one of the use of a torque versus dc input power lookup table for each of selected motor speeds below a predetermined speed and by a mathematical calculation of a plurality of power losses in relation to the dc input power and the inverter frequency for motor speeds above that selected speed.

Torque determination for control of an induction motor apparatus

An AC induction motor is energized by a voltage fed inverter coupled with a DC power source and is controlled in response to a torque request signal that is provided to accelerate or decelerate the motor as desired to maintain a desired torque output. The motor is operated to have each of a power and brake operation below the base speed of the motor and to have each of a power and brake operation above the base speed of the motor.

Induction motor control apparatus and method

An AC induction motor brake control apparatus and method are provided for energizing the motor with an inverter supplied first voltage and an additional brake circuit supplied second voltage in phase with and additive to the first voltage as required to determine a desired brake torque above base speed operation.

Induction motor regenerative brake control apparatus and method

A control apparatus and method are provided for a load energized by an inverter coupled with a DC power source. The lag current angle between the current and the load voltage is utilized to determine when the output current is positive and when the output current is negative. The conduction times of the respective upper and lower gate turn off thyristors of each pole of the inverter are controlled in relation to the established current angle, with a provided modification of those conduction times being phased out in response to the desired output voltage for said load.

AC induction motor energized by an inverter coupled with a DC power source. Upon shutdown of the inverter because of a fault condition or a rail gap between adjacent power sources, if the motor rotating frequency is greater than a minimum frequency then a decreased motor voltage is applied to the motor and increased as a ramp over a provided time delay period, after which the motor slip is controlled to provide a desired motor torque that is increased over a subsequent time delay period.

Induction motor control apparatus and method for restart when rotating

An arrangement of interconnected timers is provided for operation with a microprocessor programmed to determine time delay counts that are fed out to these timers such that the timers can take care of the actual task of firing GTO inverter switches or not firing GTO inverter switches coupled with an AC traction motor for a vehicle. It is necessary to have correct transitions between the minus GTO switch and the plus GTO switch being ON for providing the desired motor voltage conditions with minimum electromagnetic interference in relation to the power supply. In addition the use of timer queues in complicated synthesis modes like the PWM and the quasi six-step operates to give the microprocessor adequate operating time for reasonable control signal time duration calculations. The timers are synchronized in hardware by a single crystal frequency, and they are synchronized in software such that the three phase independent waveforms stay 120.degree. apart.

Growing community of inventors

South Park Township, PA, United States of America

David J Shero