Zero-Sequence Current Suppression for Open-Winding Permanent Magnet Brushless Motor Driving System Based on Second Order Generalized Integrator

Abstract

The open-winding driving system can improve power density and torque output capacity of the motor. However, the open-winding topology with a common direct current (DC) power supply provides a path for the zero-sequence current, which contributes to the power loss but not the torque output. The zero-sequence current is produced by the common-mode voltage and zero-sequence components of the back electromotive force (EMF). For the purpose of eliminating the common-mode voltage as well as improving the utilization of DC supply voltage, a 120° decoupling space vector pulse width modulation strategy is adopted. Meanwhile, a proportional unit combined with second order generalized integrator (SOGI) is proposed to suppress the zero-sequence current caused by the zero-sequence components of the back EMF. A test bench is built for the experiment. The effectiveness of the proposed suppression strategy is verified by the experimental results.

Keywords

• Electric machines
• permanent magnet machines
• open-winding motor
• zero-sequence current suppression