A dual three-phase drive system with a reduced switch count

A dual CRPWM VSI based on multiple two-phase PWM inverters, also called a B4 topology, requiring a dual three-phase drive system with reduced switch count is proposed. The drive utilizes a total of only eight switches to produce two sets of three-phase sinusoidal output currents. This new scheme minimizes the single-phase current flow through the DC-link capacitors, which is a common problem in reduced switch count topologies. By controlling the phase and magnitude of the currents generated by each inverter it is possible to cancel out the single-phase current flow through the DC-link capacitors. The paper presents a mathematical model of the proposed dual motor drive system including a control strategy that minimizes the capacitor's voltage variations and the single-phase current flow through the DC-link capacitors. In order to verify the performance of the proposed drive system, an application on traction of an electric vehicle is carried out. The simulation results show that the single-phase current flow through the DC-link can be eliminated or minimized when the vehicle moves in a straight-line regime, turning regime, or slippage condition.