Bidirectional, three-port, three-phase multilevel inverter based on switched-capacitor cells

Multiport power conversion hardware offers a means of combining multiple renewable energy sources into a single piece of hardware. Most approaches add additional hardware to existing topologies to achieve this aim. In contrast to previous work, the following paper examines existing topologies to uncover hidden nodes that can be used to add additional ports. Furthermore, high speed switching devices created from wide bandgap materials are employed to realize this new functionality. Presented to support this theory is a three-port, three-phase, multilevel inverter based on switched-capacitor cells. It takes advantage of silicon carbide's (SiC) faster switching speed to realize an extra port by modifying only the pulse width modulation strategy. It is capable of transferring power in any direction between any of its three ports: a DC bus, a two level inverter, and a three level inverter. Included in the paper, are the theory behind the circuit's operation. Additionally, a SiC based prototype has been created and tested. Experimental results demonstrate the dual 3Φ AC output capability of this topology.