Linear Inductance Model Reshaping-Based Sensorless Position Estimation Method for SRM With Antimagnetic Saturation Capability

This article focuses on the linear inductance model-based sensorless position estimation for medium- and low-speed switched reluctance motor (SRM) drive. With the developed model reshaping schemes, the position estimation error caused by magnetic saturation is effectively suppressed. Given the specific constant sum characteristics of phase inductances under unsaturation condition, a virtual inductance construction strategy is specially proposed for three-phase SRMs to avoid the impact of magnetic saturation, which shows excellent enforceability and simplicity. On the other hand, to meet the requirement of strong portability for three-phase and above multiphase SRMs, an equivalent position triangle is built in real time to recognize the position error caused by magnetic saturation and assist in a novel self-calibration technique of the inductance linearity. Both the reshaping schemes can achieve the high-precision sensorless position estimation under severer magnetic saturation. The simulation and experiments on a 150-W three-phase 12-/8-pole SRM prototype validate the feasibility and effectiveness of the proposed sensorless estimation schemes.