Modeling Of High-frequency Transformer Distributed Parameter And Research Of Its Test Method

With the rapid development of power electronic technology, switching power supplies develop towards high-frequency and miniaturization. As an important part of switching power supply, the working frequency of high-frequency transformer is continuously increasing in order to coordinate with the development of switching power supply. However, different transformer models are required for different frequencies to describe the operating performance. And measuring stay parameters accurately is the precondition of establishing the model of the transformer. So the research of stray parameters of the model and its test method have practical application value.This thesis begins with the project of high-frequency transformer based on AP method, the impact of leakage inductance and stray capacitance on the characteristics of the transformer are analyzed, and the theoretical calculation formulas of leakage inductance and stray capacitance are derived. All the existing stray parameter models of transformer are classified according to the number of distributed capacitances in high-frequency transformer models. The structure, advantages and disadvantages, and the scope of application of each type of transformer models are detailed later. Based on a specification of 40kHz/10 kVA, the Ansoft Maxwell Software is used for the finite element analysis, more accurate results are got by means of reasonable modeling and post-processing of electromagnetic field.Finally, all the existing measurement methods of stray parameters are summarized in this thesis, a new method of measurement and its calculation process are given based on three capacitance model that engineering commonly used. The stray parameters of transformer are calculated according to the results measured by this method, and comparison and analysis are made with the finite element simulation results. Then, the simulation of three capacitances model is compared with physical experiment, the tri-capacitance stray parameters of the above sample transformer are figured out. Analyse the accuracy of the model when the frequency of the model is changed, then the corresponding conclusions are acquired.