Research on MTPA Control of Permanent Magnet Synchronous Motor Based on Virtual Signal Injection

This study aims to explore the Maximum Torque Per Ampere (MTPA) control strategy for Interior Permanent Magnet Synchronous Motor (IPMSM) based on Virtual Signal Injection (VSI). As a nonlinear dynamic system, the mathematical model of IPMSM is established under ideal conditions that ignore hysteresis and eddy current losses, including voltage and electromagnetic torque formulas. The core of the MTPA control strategy is to minimize the current while maintaining the same torque output, achieved by analyzing the stator current vector in the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$d-q$</tex> axis coordinate system. The study further proposes the VSI-MTPA control strategy to reduce the impact of motor parameter variations on the control strategy and improve the accuracy of operating point tracking. By transforming the voltage formulas during stable motor operation into a simpler form and combining them with the virtual signal injection method, we derived the expression of electromagnetic torque concerning the current angle, thereby avoiding the influence of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$q$</tex>-axis inductance and permanent magnet flux linkage on the operating point. The proposed control strategy not only improves the efficiency and accuracy of motor operation but also exhibits good robustness against motor parameter variations, providing a new perspective for the control of IPMSM.