Equilibrating Winding Currents in a DC Transformer for Future Electric Transport Application based on Inductive Power Transfer

Due to the large currents circulating through the inductive link that act as a transformer in DC Transformer application, it is needed to design it using parallel litz-wire conductors to reduce the power losses. A problem of unbalanced currents arises because of not optimum winding techniques and not uniform flux distribution among the windings. In this work, we have analyzed this problem by conducting FE simulation and we propose a methodology to solve the detected problem, verified and validated using FE tools and experimental results. With the implemented improvement, we can reduce the current unbalance in the high current windings up to 50%, increasing the overall efficiency up to 2%. All the experiments were done with a 17 kW prototype that converts 2.4 kV to 200 V with an efficiency of 95%.