DC-Link Current Ripple Reduction in Switched Reluctance Machine Drives

Switched reluctance machine (SRM) drive requires a large dc-link capacitor due to the low-frequency harmonics in dc-link current, which is generated during the current commutation between phases. Installing a bulky capacitor bank in the drive has a significant impact on the cost and the overall volumetric power density of the drive. This article analyzes the dc-link current ripple in SRM drive and proposes a control algorithm to reduce the dc-link current ripple while maintaining the machine performance. The proposed algorithm extracts the ripple components from the dc-link current using a high-pass filter. The controller ensures ripple energy circulation between the phases and reduces the pulsating energy requirement from the dc supply. The dc-link ripple is suppressed at a wide speed range of operation to enable efficient and reliable drive operation without adding any external hardware system. Simulation and experimental results are provided to prove the effectiveness of the proposed control technique for both steady-state and transient conditions.