Design of a High-Voltage-Insulation and High-Efficiency Medium Frequency Transformer

Within a power electronics transformer (PET), the medium frequency transformer (MFT) is one of the key components for the whole system providing the required isolation and the voltage conversion between primary and secondary sides. A comprehensive design procedure is presented aiming to achieve high-voltage-insulation and high-efficiency. Referring to insulation standard, transformer insulation parameters are determined. To achieve the high efficiency, the number of turns is discussed considering both the calculated core loss and the estimated winding loss. A 30kVA transformer prototype is constructed and extensive measurements are performed including insulation tests, transformer loss and parasitic capacitance. The transformer prototype passes the IEEE Std. C57.12.01 standard in terms of insulation and performs well in a resonant DC-DC converter. The measured winding and core losses under rated voltage and current are 117.9W and 72.4W respectively.