Output power maximization and optimal symmetric freewheeling excitation for Switched Reluctance Generators

Space constraint is a limiting factor in widespread commercial adaptation of Switched Reluctance Generators (SRG). Maximizing the output power of the SRG, and minimizing the DC bus filter size, are among possible solutions. The output power profiles of a typical SRG are determined by applying various excitation angles. Excitation for maximum output power is obtained while considering the maximum RMS value of the phase current as a constraint. DC bus current of an SRG drive, operating in single pulse mode, is highly distorted by low frequency ripples. Introducing a freewheeling angle in the excitation pattern can lower the current ripple factor. A novel transform is proposed to establish a correspondence between the conventional and freewheeling excitation patterns. Based on which, optimal symmetric freewheeling excitation is proposed that achieves the optimal freewheeling angle and minimizes the ripple factor of the DC bus current, while preserving the maximum output power. Numerical simulation and hardware measurements verify the proposed methodology.