Modeling and Optimization of an Integrated Magnetic Component for Bidirectional On-Board Charger Applications

Lu Qu
Shenzhen Institute & Information Technology, Shenzhen 518000, Gugangdong Province, China
Jiayu Xu
Guangdong Gongye Technology Co., Ltd, Dongguan 523000, Gugangdong Province, China

Abstract:

The bidirectional CLLC topology operates over a wide range of voltages in constant-bus on-board chargers. The magnetic elements in the resonant topology have a large frequency span, high conversion power. Under heat dissipation by water cooling method, it is necessary to carry out accurate loss analysis and temperature prediction for the magnetic components. This paper presents a design method for magnetic integrated elements for inductors and transformers in resonant topology and establishes the loss model of the entire magnetic element. Based on the model, the variation trend of the loss and its influence on the design of the resonant parameters in a wide range of output conditions were analyzed. The finite element analysis software COMSOL was used to build a temperature model of the magnetic integrated components and predict their rise in temperature. This paper also summarizes the step-by-step design method for magnetically integrated components. A 6.6-kW bidirectional on-board charger was built to verify the proposed magnetically integrated components. The designed magnetic integrated components can satisfy the requirements of a wide range of battery voltages. The overall charger adopts a Si tube, with a CLLC topological efficiency of up to 97.5% and a volume of 182.7 cm3.