Medium Voltage Auxiliary Power Supply using Forward Converter integrated with Switched Capacitor Cells

This paper proposes a new DC-DC converter for auxiliary power applications with high input voltage. The proposed structure integrates switched capacitor cells with a forward converter. The input voltage is divided through the SC (switched-capacitor) cells, enabling switches rated for a lower voltage level. The proposed integration is performed using a method in which switches are shared between the SC and forward stages, which requires only a pair of complementary PWM signals to control it. The paper addresses the theoretical study of the integration, the static characteristics, and the study of ZVS (zero voltage switching). The converter employs CPM (current programmed control), and its modeling is presented along with the validation of dynamic models through simulation. Due to the SC cell's natural self-balance characteristic, no additional control loops are required to balance the voltage on the SC cell capacitors. Experimental results are presented for the proposed topology with four SC cells, rated power of 200 W, input voltage of 2 kV, and output voltage of 24 V. An efficiency of 90.66% at rated power was obtained.