Research on Modular Inverter Control Technology of Dual Three-Phase Permanent Magnet Synchronous Motor

Using medium-voltage DC transmission instead of traditional three-phase AC transmission can significantly reduce cable losses. However, high DC bus voltages pose challenges for voltage equalization across inverter modules. This paper proposes a topology for a modular dual three-phase permanent magnet synchronous motor (PMSM) inverter, and studies its dual closed-loop vector control and modular inverter voltage equalization control strategies. By using a series connection of inverters and three-phase decoupled PWM technology for individual control of inverter modules, a modular inverter series bus voltage equalization control strategy is established. Compared to parallel modular inverter, it can further reduce voltage fluctuations and enhance the dynamic performance of the motor. Simulation has verified the performance of the motor operation based on this control strategy, demonstrating that this method can achieve effective voltage equalization.