A $15$ kW three$-$phase five$-$level flying capacitor inverter is fed by $600$ VDC and is expected to achieve an RMS output line$-$to$-$line voltage that varies between $208$ and $240$ V RMS$.$

a$.$ From the literature, choose a modulation or switching strategy that allows this inverter to achieve the desired output voltage. Explain the strategy and draw a full inverter output voltage regulation control block diagram.

b$.$ Simulate this inverter with a resistive load at full power, and verify that the switching or modulation strategy you selected achieves the correct RMS values across the desired output voltage range.