An Improved Sensorless Method of IPMSM Considering Magnetic Saturation and Cross-Coupling Effect

Aiming at the defects of traditional high-frequency voltage injection method, such as complex demodulation process, bandwidth limitation and estimation accuracy susceptible to magnetic circuit saturation and cross-coupling effect, an interior permanent magnet synchronous machine (IPMSM) sensorless optimization algorithm based on discrete current characteristic analysis and on-line identification of inductance error is proposed. Firstly, a high-frequency voltage model considering cross-saturation effect is established, and two orthogonal high-frequency square-wave voltage signals are injected into the stationary coordinate system, and the high-frequency responsecurrentsare separated by the designed comb filter. A comb filter is designed to separate the high-frequency response current, and the initial value of the rotor position is demodulated by using the high-frequency current at the adjacent sampling time. In the process of separation and demodulation, the disadvantages of the filter are eliminated, and the amount of calculation is small. Then, the relationship between inductance parameters and estimation error is analyzed. The inductance identification method and rotor position estimation error compensation strategy for orthogonal square-wave injection method are proposed. Finally, the estimated error identification result is compensated to the initial value of the rotor position, which improves the estimation accuracy. The experiment on the 15kW motor control platform proves the feasibility and effectiveness of the strategy. The experimental results show that the method is simple and reliable, and is not affected by the change of inductance parameters under load. © 2020, Electrical Technology Press Co. Ltd. All right reserved.