Performance improvement of ultra-high-speed PMSM drive system based on DTC by using SiC inverter

This paper examines the control performance of a permanent magnet synchronous motor drive system based on direct torque control (DTC) using a SiC-MOSFET inverter (SiC inverter). The dead-time of the inverter affects the performance of the motor control. In high-speed drives, the dead-time effect increases because the control period becomes shorter. By using a SiC inverter for which the switching speed is faster than that of the Si-IGBT inverter, the dead-time can be shortened, and performance improvement of the control is expected. This paper also proposes a sensorless starting method using DTC. It is difficult to start the motor in a drive system without a position sensor. In the conventional ultra-high-speed drive using DTC, the motor is started by open-loop control. Experiments reveal the effectiveness of using a SiC inverter and shortening the dead-time. In addition, the experimental results reveal the applicability of the proposed starting method.