A cost-effective dual bus current measurement scheme for current control of three-phase switched reluctance motors

Switched reluctance motors (SRMs) have been considered as a low-cost alternative for EVs/HEVs applications, which require precise current measurement for their precise control. Conventionally, a current sensor is placed in each phase for current regulation, which not only increases the cost and volume but also reduces the running reliability of the motor drives. In order to minimize the current sensors, the switching functions, working states and converter topology of a 12/8 SRM have been analyzed and a simple dual-bus current detection scheme based on two current sensors is proposed. The sensors are installed in such a way that the first sensor measures the currents of phase A and C, and the second one detects the currents of phase B and C. A special switching strategy is defined for each phase to extract the excitation currents from the detected currents through the dual sensors. Finally, simulation and experimental results based on a 12/8-pole SRM drive are provided to verify the effectiveness of the proposed scheme.