Minimized current sensor and power switches for four-phase low-cost switched reluctance motors

SRMs are widely used for propulsion in EVs because of their simple structure and fault-tolerant capabilities. Nonetheless, the cost of the drive system is a critical factor for large scale commercialization. This paper proposes a low-cost drive system for a four-phase SRM. Firstly, a simplified converter topology with fewer power switches compared to the standard one is developed. Then, unlike the conventional current sensing scheme where a current sensor is employed in each phase for current detection, a single current sensor is placed in the lower dc-link for current control. The SRM was well controlled through the simplified power converter and single current sensor. Finally, the proposed techniques are thoroughly verified through MATLAB simulations using an 8/6-pole SRM model. The simulation results well demonstrate the feasibility of the presented schemes.