Impact of Parasitic Capacitors on Cell Capacitor Voltage Balance in Power Converters Having Integrated Capacitor Blocked Transistor Cells

Power converters built with series-connected Integrated Capacitor Blocked Transistor (ICBT) cells have the capability to transfer power at higher voltages while using switching devices with lower voltage ratings. ICBT cells bring little additional losses and do not require large cell capacitors or fast capacitor voltage balancing control methods. However, the converter operation may be impacted by the parasitic capacitors because of the fast voltage changes across the parasitic capacitors during the switching transients. Specifically, the parasitic capacitors between device terminals to ground may cause voltage unbalance among the cell capacitors. The impact of different types of parasitic capacitors at different converter operation conditions are analyzed. Based on the results, solutions to mitigate and compensate the impact are explored.