Analysis and Design Considerations of a Buck-Boost Energy Recovery-Based Power Converter for SRM Drive

This article presents the development of a dynamic model and a design approach for the recently proposed buck-boost energy recovery circuit (BBERC) based power converter for a switched reluctance motor (SRM). The advantage of an increased demagnetization voltage in reducing the commutation torque ripple is analyzed using analytical and simulation-based studies. Though there have been several studies on the steady state behavior of the energy recovery stage in the literature, the dynamics of the same have never been investigated. An equation-based small signal model to describe the dynamic behavior of the energy recovery stage is proposed, which can be used to estimate the overshoots and oscillations in the inductor current and capacitor voltage during the dynamics. This article also evaluates the effects of discontinuous conduction mode (DCM) of operation of the BBERC on the drive performance, which has also not been addressed in the prior art. Furthermore, a method for the design of the energy recovery stage considering the continuous conduction of the energy recovery inductor is proposed. Additionally, the advantages of BBERC are reemphasized by comparing it with other energy recovery-based topologies such as energy efficient C-dump converter (EECDC). The analyses presented in this article are validated with experiments and simulations.