Comparative study of control characteristics in ultra-high-speed PMSM drives

This paper discusses effects of short control period on control characteristics in an ultra-high-speed permanent magnet synchronous motor (PMSM) drive system based on direct torque control (DTC). High-performance control in ultra-high-speed region requires fast response time of control system and also short computation time. The DTC-based drive system has several advantages, including simple structure and sensorless drive, which are important for ultra-high-speed drives. In addition, short control period is achieved by using high-speed logic circuit. In this study, the DTC is implemented in a field programmable gate array (FPGA). Simulation and experiment are performed to discuss the effects of short control period in the steady-state. In particular, this paper shows control characteristics such as torque ripple and harmonics of the phase current under various control periods.