An Adaptive MTPA Control Method for Interior Permanent Magnet Synchronous Motors Considering Demagnetization and Temperature Effects

For the interior permanent magnet synchronous motors (IPMSMs), the flux linkage variations caused by demagnetization and temperature effects commonly exist, which deteriorate the accuracy of maximum torque per ampere (MTPA) operation. This paper proposes an adaptive MTPA control method for IPMSM drives that takes into account the flux variations. The method works by considering the relationships among the flux linkage of the permanent magnet, the d-axis current, and the temperature using the knowledge of the demagnetization curves. The optimal current angle for the MTPA operation is online computed by updating the flux linkage. The proposed adaptive MTPA control strategy is demonstrated on a speed servo control system of the IPMSM. Simulation studies are carried out to validate the effectiveness and robustness of the proposed control method.