A Novel 4-level Converter with Inherent Voltage Boosting for 4-Phase SRM

Abstract

The paper proposes a new 4-level converter configuration for a 4-phase, 8/6 switched reluctance motor (SRM) drive. The proposed converter is based on double bridge topology and shares a common leg for the quadrature phases in 4-phase SRM. The common leg allows the discharging quadrature-phase energy to charge the corresponding capacitor in the bridge. This, during the energization of the corresponding quadrature-phase, provides a maximum boost in voltage. Thus, an inherent voltage boosting is achieved. Analysis of different operating modes of the proposed converter is discussed. The proposed converter's effectiveness is verified through the simulation studies in the MATLAB/Simulink environment on a prototype 4-phase 8/6 SRM, designed in ANSYS/Maxwell. The proposed converter configuration uses the same number of switches and diodes as in a conventional three-level asymmetric half-bridge converter (TL-AHB). However, due to inherent boosting capability in the proposed converter configuration, the constant torque region, and the smooth torque output region are extended by 25%, compared with TL-AHB.