Phase Current Reconstruction Scheme of SRM Drives Based on Interleaved Pulse Injection Using Single DC-Link Current Sensor

For the control and drive protection of switched reluctance motor (SRM), it is necessary to acquire accurate phase current. A phase current reconstruction method is proposed for the single-current-sensor SRM drive system. Firstly, the operating principles of SRM are analyzed based on the three-phase asymmetric half bridge (AHB) topology. Then, a phase current reconstruction method based on interleaved pulse injection is proposed, which injects interleaved pulses with large duty cycle into the down switch of conduction phase, decouples the dc-link current under different operating states, and reconstructs the phase current. The number of current sensors, the size and cost of the driver are reduced by the proposed method. Moreover, it improves the reliability of the system and is appropriate for control modes such as current chopping control (CCC), voltage-pulsewidth modulation (PWM) control and single pulse control (SPC). It does not require additional circuits or change of the converter topology, and can realize current reconstruction of the conduction phase and the idle phase. Finally, combined with the proposed method, the overall control strategy is realized. The effectiveness of the proposed phase current reconstruction method is verified on a 750 W 12/8 SRM.