Abstract：In recent years, LLC resonant converter has been widely used because of its superior performance. The structure of parallel LLC resonant converter is very suitable for low voltage and large current applications, but it has the difficulty of current sharing between modules. A small difference in the parameters of the resonant network may cause large module current imbalance. In this paper, the virtual impedance is used to simulate the series impedance of the resonant network from the point of impedance. To improve the current sharing characteristics, the equivalent output impedance is adjusted by the series impedance. Taking two-parallel LLC module as an example, the control block diagram and the realization method based on the virtual impedance are given. Finally, using DSP digital control, a prototype of a two-phase parallel LLC resonant converter with 400V input and 12V/80A output is built. The experimental results show that the proposed control method can reduce the output current imbalance to 5% within the full load range, which verifies the proposed method.
任小永, 王亚坤, 陈宇, 张之梁, 陈乾宏. 基于虚拟阻抗的LLC谐振变换器并联均流控制[J]. 电工技术学报, 2019, 34(21): 4540-4550.
Ren Xiaoyong, Wang Yakun, Chen Yu, Zhang Zhiliang, Chen Qianhong. Parallel Current Sharing Control of LLC Resonant Converter Based on Virtual Impedance. Transactions of China Electrotechnical Society, 2019, 34(21): 4540-4550.
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2019, Vol. 34 
