Minimized Overmodulation Voltage Extension for PMSM Field-Weakening Control With Adaptive Dynamic Enhancement

Overmodulation-combined field-weakening (OCFW) control scheme is a necessary access for PMSM to extend the torque to extreme. However, traditional OCFW method always uses six-step fundamental voltage as the F-W reference regardless of operation conditions, leading to redundant voltage extension as well as harmonics. To solve it, a minimized overmodulation voltage extension method is proposed to eliminate the unnecessary voltage extension through reasonable F-W reference compensation. Through the relation between voltage reference and overmodulation depth, the minimized F-W reference can be depicted on the operation plane considering torque and speed. Moreover, a dynamic enhancement module ensures rapidity by holding six-step operation in dynamic state. The proposed method can eliminate the redundant voltage extension and reduce torque harmonics of OCFW control, with its effectiveness experimentally validated on a 2.2 kW PMSM test bench.