Loss Minimum Control of Surface Permanent Magnet Synchronous Motor Based on Virtual Complementary Square Wave Signal Injection

In order to improve the effectiveness of the virtual signal injection method in the efficiency optimization of surface permanent magnet synchronous motor (SPMSM), this article analyzes the influence factors affecting the inaccurate acquisition of the efficiency derivative to current angular in the traditional method and then proposes a loss minimum control (LMC) strategy based on virtual complementary square wave signal injection. First, the drawbacks of virtual square wave signal injection based on the traditional method are analyzed. Then, based on the mathematical model considering iron loss, this article proposes a criterion reflecting the loss of SPMSM. Meanwhile, to accurately acquire the loss derivative to d-axis current, the method injects a pair of complementary square wave signals into the d- and q-axis magnetizing current components and then obtains the iron loss derivative to d- and q-axis magnetizing current components. Finally, the online setting of the d-axis current reference is designed by using the extracted derivative information. This method not only avoids the high-order derivative term in the traditional method but also avoids the approximate simplification of the equation, thereby improving the accuracy of the current reference setting. The effectiveness of the proposed method is verified by experiment.