Buck-Boost Operation by Zero-Sequence Current Control for Negative-Point-Connected Dual Inverter with Variable Voltage Capacitor

This paper proposes a circuit topology and a control strategy to expand the speed range of an open-end winding interior permanent magnet synchronous motor by dual inverter topology. In the proposed circuit configuration, the primary voltage-source-inverter has an DC voltage supply, while the secondary voltage-source-inverter has a capacitor. In addition, the negative-point of both inverters' DC link is commonly connected. This configuration can remove the isolated power source suppling to the gate driver in the negative side switches. The aim of this study is to achieve the speed range expansion by boosting the secondary capacitor voltage. In this paper, a basic principle of the negative-point-connected dual inverter topology and its control strategy are introduced. Furthermore, by the proposed control strategy, the capacitor voltage control operation using zero-sequence voltage is confirmed by simulation.