Rotor position tolerant detection method for SRM drive system with misaligned position sensors

Abstract

Accurate rotor position is necessary for the control of switched reluctance motors (SRMs). Generally, three position sensors are ideally installed 120 electrical degrees apart for three-phase SRMs. However, the placement of position sensors may be inaccurate, particularly in small-size SRMs, and there is no method reported to deal with this problem up to now. Firstly, the position signals and the influence of the misaligned sensors on the detected rotor position are investigated. Then a novel method is developed to identify the misaligned position sensors with dynamic time warping (DTW) algorithm. The DTW distance versus the misaligned angle is calculated, and the relationship between them is described with linear regression analysis algorithm. Then the rotor position tolerant detection method is realised by compensating the misaligned angle in real time. Finally, comparative experiments are carried out on a three-phase 12/8 SRM drive system, and it can be found that the proposed strategy is capable of providing an accurate rotor position for the SRM drive system. The presented method is easy for online implementation and can be integrated into the control system conveniently.