Loss Characteristics of PMSM Drive System for Inverter Switching

The demand for energy conservation has led to a need for higher efficiency in the permanent magnet synchronous motor (PMSM) drive system, including the inverter. To date, studies have focused on the trade-off between inverter switching losses and motor copper and iron losses. Focusing on the recent development of power semiconductor devices, higher breakdown voltages, and lower losses have been realized. Therefore, in this trade-off relationship in the future, increasing the switching frequency and reducing motor losses are expected to lead to higher efficiency of the PMSM drive system. In this study, PMSM drive system losses were measured and analyzed in a system of a 1 kW PMSM and insulated gate bipolar transistor (IGBT) inverter when driven in the asynchronous pulse width modulation (PWM) carrier frequency of 10 kHz and the synchronous PWM 3-pulse mode. The results reveal that effectively reducing motor losses by increasing the switching frequency is more effective for the efficiency of the PMSM drive system than reducing inverter losses by decreasing the switching frequency.