A Medium Voltage Input Multiport Isolated Output DC Transformer With Power Self-Balancing and Output Fault Isolation

Medium voltage dc converters with multiple output ports have the challenges of series input module power balancing control and fault isolation between output ports. This article proposes a new medium voltage input multiport isolated output dc transformer topology. The proposed topology can be extended to up to 2 k-1 output ports of different voltages with k modules input connected in series. Moreover, the proposed topology has the voltage self-balancing feature of input modules since they are coupled via the balancing capacitors. Current self-balancing of all mosfets is also achieved, as the equivalent impedance of multiple voltage sources discharging to multiple loads is the same under the influence of the split resonant inductor. Besides, the proposed topology can limit the shorted current in the output port automatically without affecting other ports, due to the impedance of the resonant tank of the faulty port being clamped. A 2 kV dc input with three output ports of 410 V, 380 V, and 40 V prototype is built to verify the feasibility of the proposed topology. The results show that the proposed topology has multiple module power self-balancing feature, and can improve the reliability of the multiport power supply systems. Therefore, it has good prospects for subsea dc power distribution systems and ship electric power distribution systems.