Novel Dynamic Overmodulation Method for Six-Step Operation with Enhanced Transient Performance of Current Control in IPMSM Drives

This paper proposes a novel dynamic overmodulation (OVM) method for six-step operation that maximizes the output voltage of inverter, while enhancing the transient performance of current control in interior permanent magnet synchronous motor (IPMSM) drives. It modifies the reference voltage to converge at six vertices of voltage hexagon as its magnitude increases. This ensures the six-step operation. Also, it can achieve the low overshoot of negative d-axis current and fast dynamic performance of current control by simply using the scaled voltage modification based on cross-coupled characteristics of IPMSM. Consequently, the proposed OVM method can improve both the voltage utilization of inverter and transient performance of current control. Its effectiveness is verified through the simulation tests.