Harmonic Analysis and Suppression of Position Sensorless Control by PMSM High Frequency Signal Injection Method Considering Inductive Asymmetry

In the position sensorless control of permanent magnet synchronous motor (PMSM) based on pulsed vibration high-frequency voltage injection method, the position detection accuracy is very important. In this paper, firstly, the second harmonic error brought by the asymmetry of motor three-phase inductance to the sensorless control of PMSM based on carrier signal injection is theoretically analyzed, the specific expression of the second harmonic error is derived, and simulations are carried out to verify it. In addition, a novel position observation structure is proposed to suppress the second harmonic error using a second-order generalized integrator (SOGI), and a new strategy for suppressing the second harmonic error in combination with SOGI is proposed. Finally, simulation experiments using MATLAB/Simulink are conducted to verify that the proposed strategy can not only have better static performance, but also effectively eliminate the second harmonic error of position estimation during sudden changes in PMSM speed and load.