A modular buck-boost drive system for torque ripple minimization of switched reluctance machines

Abstract

In this paper, a modular three-phase buck-boost switched reluctance machine (SRM) drive system is proposed. In this topology, the three-phase SRM drive is composed of three single-phase modules that are connected in parallel where each single-phase inverter module is formed with a bidirectional buck-boost DC/DC converter and a cascaded H-bridge inverter. The DC/DC converter generates the rectified form of the phase voltage and the H-bridge inverter alternates and controls the polarity of the output voltage. This structure allows one to adjust the phase voltages independently, which provides faster excitation and demagnetization for a wide range of operating conditions. Since the voltage is always regulated dynamically, the need for bulky DC-bus capacitors is eliminated; hence, the size and the cost of the drive system are reduced. To validate the superiority of the proposed system and compare it with the traditional one, a set of simulations are done in MATLAB® /Simulink® . Not only the torque ripple is reduced, but also a higher torque per ampere ratio is achieved with the proposed system.