Research on Anti-DC Bias and High-Order Harmonics of a Fifth-Order Flux Observer for IPMSM Sensorless Drive

Due to various nonideal factors, including the motor parameter mismatches, detection errors, converter nonlinearities, noise, etc., dc bias and high-order harmonics exist in the flux model, which make the traditional flux observer estimation inaccurate. In order to suppress dc bias and high-order harmonics, an interior permanent magnet synchronous motors (IPMSM) sensorless drive method based on a fifth-order flux observer (FOFO) is proposed in this article. The proposed FOFO can completely remove dc bias and has a strong filtering ability for high-order harmonics. Additionally, the parameters of the FOFO are set through the s -domain analysis. Then, the discrete FOFO is obtained for better implementation in digital systems. The proposed FOFO is verified by experiments on a 2.0-kW IPMSM drive platform.