Voltage Angle Regulated Field Weakening Control Based on Overmodulation Strategy for PMa-SynRM Drives

Due to the issue of voltage saturation by the voltage closed-loop field weakening (FW) method in the overmodulation (OVM) region, the current performance of the permanent magnet assisted synchronous reluctance motor (PMa-SynRM) would deteriorate. In this paper, a voltage angle regulated FW control based on OVM strategy is proposed to extend the speed and torque range and reduce the current harmonics. The d-q axis voltages are directly decoupled by the voltage angle, which solves the issue of the coupling of the current loop and the voltage loop. Based on this, the output voltages are corrected according to the OVM region judgement, and the six-step operation is adopted to increase the utilization of the DC-bus voltage. The experimental results show the effectiveness of the proposed method under different operation conditions.