A Measurement Method of Winding Loss for High-Frequency Transformer Based on Auxiliary Winding

The measurement of winding loss is a difficult issue in the modeling and design of high-power high-frequency transformers (HFT), and a high precision winding loss measurement method is an important tool for verifying the correctness of winding loss theory and improving the accuracy of modeling and simulation. The accuracy of short-circuit impedance measurement method widely used at present decreases with the increase of measurement frequency, so it is not suitable for HFT. Creating additional measurement nodes by aiding auxiliary windings (AW) is an effective measure to improve the measurement accuracy of winding loss. An equivalent circuit model including stray parameters of AW was established, and the analysis results show that the leakage inductance and coupling capacitance between AW and winding under test (WUT) greatly affect the frequency range and accuracy of winding loss measurement. A correction method of winding resistance measurement considering coupling capacitance was proposed, which extended the measurement range of frequency and kept the measurement accuracy under high frequency. A single strand in Litz wire winding was used as AW, the leakage between AW and WUT was thus reduced to a very low level, and the engineering practice of winding loss measurement was simplified. By measuring the winding parameters of a 100kVA HFT prototype, the circuit model and the correction method were verified, and the effective measurement of the winding AC resistance at 1MHz was realized. © 2022, Electrical Technology Press Co. Ltd. All right reserved.