A Study on the Application of the PMSM Vector Control System for High Speed Motor in Inverter Overmodulation Range

Abstract

This paper describes a study on the vector control system for PMSM driven in frequency over kHz. As PMSM is generally driven by inverter, of which switching frequency is around 10kHz, driving voltage waveform become a pseudo rectangular wave rather than pseudo sinusoidal wave in the drive frequency (overmodulation mode of inverter). Therefore unavoidable low order harmonic current appears in current control loop and makes some troubles. Especially, the harmonics components disturb the closed current control system and limit the maximum speed/torque as a results. To solve this problem, authors have proposed a control system with harmonic current estimator, which reduces the harmonic components in the feedback current. Then, the control system has been evaluated in only driving frequency below 100Hz. In this paper, the proposed system is advanced for driving PMSM in frequency over kHz. The simulation results confirmed that the improved system can be applied to high speed motor.