Optimal Design of Planar Magnetic Integrated Matrix Transformer for High Frequency LLC Converter
Xiao Long1,2, Wu Liang1, Li Xin1, Zhao Jun1, Chen Guozhu1
1. College of Electrical Engineering Zhejiang University Hangzhou 310027 China; 2. School of Electronic and Electrical Engineering Minnan University of Science and Technology Quanzhou 362700 China
Abstract：Matrix transformer is widely used that the input side windings are connected in series and output side windings are connected in parallel, which can improve the efficiency and power density of LLC converter applied in low voltage and large current application as well as solving the problems of current imbalance and hot spot caused by device paralleling. However, traditional matrix transformers are mostly implemented with separate magnetic cores, causing considerably large winding loss and magnetic core loss, while also limiting further improvement of power density. Based on magnetic flux cancellation principle, a single core integrated matrix transformer is proposed to replace the traditional two separate magnetic cores, which can decrease the volume and loss of magnetic core. An optimal design method based on the proposed winding loss and magnetic core loss model is demonstrated to implement the tradeoff between the total loss and the footprint of the designed matrix transformer. At last, the correctness and effectiveness of the proposed matrix transformer optimal design method are verified by a 400W, 1.5MHz LLC converter prototype based on high frequency wide band-gap gallium nitride power semiconductor device.
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2020, Vol. 35 
