A novel rotor position estimation method of permanent magnet synchronous motor based on DC compensation and cascade filter

The traditional rotor position estimation method of permanent magnet synchronous motor at zero and low speed based on high-frequency pulse voltage signal injection inevitably adopts band-pass and low-pass filters, which reduces the dynamic response speed of the system. In this paper, a new rotor position estimation strategy is proposed. First, in the static coordinate system, the pulse vibration high-frequency signal with the same frequency and amplitude is injected into the α and β axis respectively. At the same time, the DC offset for rotor position estimation is extracted. Then the high-frequency pulse vibration signal is injected into the α axis, the obtained DC offset is used to compensate the current response signal, and the cascade filter is used to expand the bandwidth of the position estimation link and improve the dynamic response; Finally, at zero speed, the positive and negative square wave signals are injected into the α axis or β axis, and the initial position is determined by comparing the current amplitude of the corresponding shaft. The effectiveness of this method is verified by simulation. The results show that this method can quickly and accurately obtain the rotor position information at zero and low speed, and has good stability and dynamic characteristics.