Initial position estimation for IPMSMs using comb filters and effects on various injected signal frequencies

Abstract

This paper proposes fast initial position estimation of IPMSMs (Interior Permanent Magnet Synchronous Motors), which is based on intentional pulse voltage injection and comb filters. Most initial position estimation methods utilize the amplitude or differential values of high-frequency currents and the performance of sensorless control depends on the algorithm to reconstruct these values. Although Fourier series expansion which requires some Low-Pass Filters(LPFs) is utilized in general, the filters degrade the response of position estimation. This paper focuses on the algorithm for initial position estimation of IPMSM at standstill, and proposes a new algorithm using comb filters which can rapidly calculate amplitude values of high-frequency currents and can improve the initial position estimation performance. In addition, this paper experimentally shows the performances of the initial position estimation, starting characteristics of sensorless control and characteristics of sensorless control including standstill under the load.