Research on Sensorless Control of High Frequency Square Wave Injection PMSM Based on Improved SOGI

When the sensorless control system of permanent magnet synchronous motor (PMSM) uses the traditional high-frequency square wave voltage injection algorithm to extract the feedback current of the current loop and the high-frequency response current to obtain the rotor position information, the filtering delay caused by the use of multiple filters affects the system estimation accuracy and the problem of error accumulation. A sensorless control strategy based on the generalized second-order integrator is proposed. Firstly, in the current loop part, the generalized second-order integrator is used to extract the feedback fundamental frequency current signal; Secondly, the high-frequency response current is extracted by taking advantage of the frequency selection characteristic of SOGI. Combined with the notch characteristics of notch filter, a new type of SOGI is designed to filter out the second harmonic of the injected signal, replacing the bandpass filter and low-pass filter in the traditional error signal extraction link. The parameter setting is simple and it has the advantage of taking into account both filtering accuracy and bandwidth, improving its dynamic performance. Finally, a simulation model was built and verified in Simulink. The experimental results show that this method has better response speed and rotor position estimation accuracy compared with the traditional methods.