Pulse-width-modulation schemes for an integrated traction and compressor drive system

This paper presents pulse-width-modulation schemes for an integrated traction and compressor drive system for automotive applications. The integrated drive system employs a five-leg inverter to control a three-phase traction motor and a two-phase compressor motor and can significantly reduce the component count of the compressor drive for heating, ventilating and air-conditioning in fuel cell and hybrid electric vehicles. Because the common terminal of the two-phase motor is tied to the neutral point of the three-phase traction motor, PWM schemes that generate a zero-sequence voltage to the three-phase motor may produce an unwanted zero-sequence current. This paper presents PWM strategies for the two-phase motor to avoid this zero-sequence current and discusses in detail three commonly used three-phase PWM schemes. Experimental results are included to verify the effectiveness of the proposed methods.