A Virtual Space Vector Modulation Method to Reduce Capacitor Voltage Ripple in Dual Inverters

The dual inverter with a floating capacitor when the voltage ratio is 1:0.5 can effectively control the capacitor voltage in the fully modulated region, though it exhibits significant voltage ripple. This paper utilizes the concept of virtual space vectors, where the synthesized virtual space vector does not cause voltage fluctuations during modulation. Combining the conventional method and virtual space vector method successfully reduces capacitor voltage ripple without damaging power quality. As a result, the required floating capacitor capacitance is reduced under specific voltage fluctuation conditions, which reduces the system volume and mass. Reflected in the increased power density of the drive system. Finally, simulation results confirm that this method suppresses capacitor voltage ripple exceeding 50% under various operating conditions.