Improved Pulse Voltage Injection Method for Initial Position Estimation in Surface-Mounted Permanent Magnet Synchronous Motor

When the Permanent Magnet Synchronous Motor (PMSM) is at a standstill, an improved pulse voltage injection technique is employed. This method involves sequentially injecting short-duration, high-frequency pulse voltages with sufficient amplitude into different phases of the stator windings. This process induces significant magnetization, leading to magnetic saturation effects. The varying degrees of magnetic saturation cause different current responses, which can then be used to infer the relative position between the rotor and stator, thereby estimating the initial rotor position.