Inverter-Induction Motor Drive for Transit Cars

The advent of large power semiconductors has made it possible to apply inverters and ac motors to traction applications. Either synchronous or induction motors and several types of power converters can be considered. The induction motor and the pulsewidth modulated (PWM) inverter are selected as favorable for application to a transit car drive. A general method of sizing the PWM inverter and induction motor in terms of the car performance requirements is out-lined. This method results in a minimum size inverter and allows optimization of system weight and cost. A discussion of wheel size effects and the optimization of regenerated energy is included.