Multilevel, multiport, switched-capacitor based inverter for utility applications

The following paper proposes an improved pulse width modulation (PWM) strategy for the three-phase, three-port, multilevel inverter (3PPMLI). This method enables a single DC source to produce two AC outputs with different frequencies. The theoretical background for this strategy is presented including the operating limitations for the 3PPMLI. Experimental results for a silicon carbide (SiC) base prototype validate the proposed method. Two sets of experimental results are included. The first demonstrates the ability of the 3PPMLI to output two signals with the same frequency, but with a phase shift relative to each other. The second results shows the unit outputting two different frequencies.