Online Self-Commissioning of Unsaturated Inductance Characteristics for Low-Speed Position Sensorless Control in Switched Reluctance Machines
Abstract
In this article, a novel method for online self-commissioning of the unsaturated inductance characteristics is proposed, which is utilized for low-speed sensorless control in switched reluctance machines. First, a dual-phase current chopping method is proposed to tune the rotor to any desired position, which does not need any clamping devices or position sensors. Then, the unsaturated inductance values at some sample positions are identified by the well-known current slope difference (CSD) method. Afterward, a feature position identification method combined with a regional linear interpolation method is proposed to construct the accurate full-cycle unsaturated inductance. To this extent, the self-commissioning process finishes and the controller switches to normal sensorless control mode. High-frequency (HF) pulses are first injected into the idle phase and the discrete inductance value during each pulse is identified by CSD. Based on the self-commissioning of unsaturated inductance characteristics, the discrete rotor position corresponding to the discrete inductance value is calculated. Accordingly, the more precise real-time rotational speed and rotor position are calculated based on a phase-locked loop. Finally, the constructed unsaturated inductance and the sensorless control scheme are both verified by experiments, which demonstrates the effectiveness and accuracy of the proposed method.
