Optimal Switching Angles for Switched Reluctance Generator Operating Under Modified Single-Pulse-Mode

Switched reluctance machine (SRM) is a viable option in vehicular applications. SRM operates in single-pulse mode at speeds equal to or above its base speed. In this mode, the introduction of a zero-voltage interval between the positive and negative pulses is known to reduce the output current ripple. This excitation pattern is defined as a modified single-pulse-mode where turn-on, freewheeling, and turn-off switching angles are the only parameters determining the output of SRM at a given DC-bus voltage and speed. Multiple triplets of these switching angles can result in the same output power. The optimal choice of these switching angle triplets for desired output power is challenging. This paper proposes two novel optimal techniques, namely, optimal-1 and optima1-2, which minimize the phase rms current and DC-bus rms current, respectively, while extracting the desired output power from the SRM. The proposed optimal techniques are compared with the existing methods of operating SRM in modified single-pulse-mode. Both the optimal techniques are validated through simulations and experiments on a 4 kW, 280 V, 1500 rpm SRM running as a generator.