An improved initial rotor position estimation method using high-frequency pulsating voltage injection for PMSM

High frequency pulsating voltage injection method is a good candidate for detecting the initial rotor position of permanent magnet synchronous motor. However, traditional methods require a large number of filters, which leads to the deterioration of system stability and dynamic performance. In order to solve these problems, a new signal demodulation method is proposed in this paper. The proposed new method can directly obtain the amplitude of high-frequency current, thus eliminating the use of filters, improving system stability and dynamic performance and saving the work of adjusting filter parameters. In addition, a new magnetic polarity detection method is proposed, which is robust to current measurement noise. Finally, experiments verify the effectiveness of the method.