High power resonant Switched-Capacitor step-down converter

This paper treats a new type of high power switched-capacitor-DC-DC-converter (SCDDC), which is characterized by resonant switching transitions. This drastically reduces switching losses and opens up the possibility to employ thyristors instead of turn-off power semiconductors. At the same time a larger energy can be transferred per switching cycle and/or the application of the SCDDCs can be extended into the megawatt power range. For operation with high switching frequency thyristors are replaced by IGCTs which allow to avoid a turn-off time in reverse-blocking mode. The new converter topology is extensively analyzed using simulations. To gain practical results a small scale prototype is designed and the operation of the proposed converter is experimentally verified including the resonant operation of IGCTs which results in significantly reduced switching losses.