Initial Position Detection Strategy for PMSM Based on Improved Gradient Descent Algorithm and Elliptical Excitation Voltage Injection

The paper proposes an initial rotor position detection strategy for permanent magnet synchronous motors (PMSMs) based on high-frequency elliptical voltage injection. By analyzing the response current model of PMSM, the strategy utilizes the improved gradient descent algorithm to update and optimize the skew angle of the elliptical voltage, thereby analyzing the variation characteristics of the response current and obtaining the initial position of the rotor from it. Compared with traditional methods of initial rotor position detection, this strategy has a simpler structure, does not require specific motor parameters, and no longer relies on the cooperation of multiple filters to obtain positional information from the response current. It avoids the impact of filters on the current amplitude and reduces phase shifts caused by signal processing. The proposed initial rotor position detection strategy has been validated through simulation.