About the experimental results of an electric driving system based on asynchronous motor and PWM converter

The paper deals with special features related to the a.c. electric driving system of a trolley-bus. One presents the driving system consisting of an asynchronous motor and inverter and some aspects regarding the PWM inverter control. The tests over the manufactured asynchronous motor were performed at a frequency equal to 50 Hz (for the rated speed) and a frequency equal to 106.6 Hz corresponding to a synchronous speed equal to 3200 rpm. The inverter was separately tested, before its inclusion in the driving system and some of the tests results presented (heating tests for the main components, the behavior at the discontinuous variation of line voltage, a.o.). Some tests concerning the behavior of the entire system at forward and backward running regimes are also presented.