A Mutual Inductance Estimation Based Sensorless Control for IPMSM with Complex-Coefficient Filter in Low-Speed Range

The sensorless control of interior permanent magnet synchronous motor (IPMSM) based on high-frequency voltage injection for low-speed range has been widely studied. However, mutual inductance brings error to the rotor position estimation and decreases the robustness under the non-ideal condition of electromagnetic saturation caused by excessive current. In order to reduce the estimation error of rotor position and speed, this paper proposes a sensorless control method for IPMSM based on online mutual inductance estimation. In addition, in order to reduce the phase shift, a complex-coefficient filter (CCF) is adopted in this paper to replace the conventionally used bandpass filter (BPF) to improve the accuracy of rotor position and speed estimation. Since CCF has no phase shift and amplitude attenuation at the center frequency, high-frequency current component can be accurately extracted without any additional phase compensation.