A Novel MMC Topology for Decoupling Capacitance Minimization with an Integrated Three-Port Coupling Transformer

This paper proposed an MMC topology integrated with a three-port coupling transformer and its modulation strategy. The coupling of the three-phase sub-module capacitor greatly reduces the voltage ripple of the sub-module capacitor, thereby greatly reducing the volume and cost of the system. In addition, by integrating an arm of the additional circuit with the half-bridge of the MMC, the structure of the additional circuit can be further simplified. This paper also studies the parameter design scheme of the system. The research shows that by configuring the system parameters, partial soft switching of the decoupling circuit can be realized, thereby reducing the power loss of the system. Simulation results validate the effectiveness of the proposed topology and modulation strategy.