A Torque Control Method Based on <italic>I-MR</italic> Controller for IPMSM Drive With Small DC-Link Capacitor

Abstract

In traditional motor drive system, large volume electrolytic capacitors are utilized to buffer energy and stabilize the dc-link voltage. However, these capacitors affect the reliability of the drives and narrow the conduction angle of diode-rectifier. As a result, the grid side current is distorted and the power factor is deteriorated. In order to settle these issues, small dc-link capacitors can replace the electrolytic capacitors. In this paper, a motor torque control method with dc-link voltage feed-forward compensation for an interior permanent magnet synchronous motor (IPMSM) drive system is proposed. Hence, an integration multi-resonant (I-MR) controller is established to regulate the motor torque to obtain high input power factor and low grid current harmonics. In addition, a voltage feed-forward compensation is used to diminish the error of motor torque control. The effectiveness of the proposed method is verified through simulation and experiments. Results indicate that the input power factor can reach about 99.4% and the grid current harmonics are considerably lower than the requirement of EN-61000-3-2 standard.

Keywords

• IPMSM
• small dc-link capacitor
• high power factor
• torque control
• integration multi-resonant controller
• voltage feed-forward compensation