250kW High-Frequency Transformer Design and Verification for MVDC Collection System for Renewable Energy Resources

In the medium-voltage dc collection system for renewable energy sources, the high-power high-frequency transformer is one of the key equipment. To lower down the parasitic capacitance of high-power high-frequency transformer, the multi-layer and multi-section structure is adopted for the secondary winding. Furthermore, the multiwinding output series structure on the high-voltage side is employed as well, which is beneficial to reduce the voltage stress and voltage sharing difficulty of the rectifier diodes. A special bobbin is designed to implement the multi-winding output series structure. At last, a 250 kW high-frequency transformer is designed and manufactured with the good performance verified.