A Remedial Method Based on Field-Oriented Control for Five-Phase PMSM Under Single-Phase Open-Circuit Fault

Abstract

Field-oriented control (FOC) based on vector space decomposition (VSD) is a common method for the high-performance operation of five-phase motors. In this paper, a remedial method based on FOC for five-phase permanent magnet synchronous motor (FPMSM) with sinusoidal back electromotive force (EMF) is proposed to suppress the current distortion and torque ripple under single phase open-circuit fault (OCF). For FPMSM with sinusoidal back EMF, the circular trajectory of current in the stationary $\alpha-\beta$ frame can produce circular rotating magnetomotive force to output constant torque. After single phase OCF, the motor model based on VSD keeps unchanged because the prefault normal matrix is adopted in the decoupling transformation. However, the modulation voltages of the inverter are no longer equal to the phase voltages of the motor, resulting in current distortion and torque fluctuation. By analyzing the inverter model and motor model under single phase OCF, a remedial method is proposed, which the disturbances are suppressed by reconstructing the voltage transformation matrix and using voltage feedforward. Compared with conventional methods based on PR or double PI controllers, the structures of current controllers are no need to be changed, so this method has the advantages of simple application and avoiding complex parameter design. The simulation verifies the effectiveness of the proposed method.