Low-cost SRM drive system with reduced current sensors and position sensors

Abstract

This study presents a low-cost switched reluctance machine (SRM) drive system with reduced current sensors and position sensors. The reduction of current sensors is achieved by rearranging the location of adopted sensors, and each phase current is calculated by decomposing the current from two special positions. The reduction of position sensors is realised by optimising conventional slotted disc. Being different from the conventional three-phase 12/8 SRM drive system, the developed low-cost system only requires two current sensors and one position sensor. First, the proposed phase current detection method is illustrated in details. Second, the measures to solve the three key problems in rotor position sensing strategy are represented considering the forward and reverse direction of SRM. Third, the reliability function and the mean time to failure indicators are compared between the conventional and proposed methods. Finally, the effectiveness of the proposed methods is experimentally validated on a three-phase 12/8 SRM drive. The proposed low-cost system is easily extended to the widely used four-phase 8/6 SRM system. Moreover, the proposed strategies for the low-cost SRM drive system are not relying on the analytical motor model and easy for online implementation without additional hardware.