A Control Strategy and Design Method for Interleaved LLC Converters Operating at Variable Switching Frequency
A Control Strategy and Design Method for Interleaved LLC Converters Operating at Variable Switching Frequency
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DOI：
10.1109/tpel.2014.2300165
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发表时间：
2014-01
影响因子：
6.7
通讯作者：
Zhiyuan Hu;Ya-jie Qiu;Yanfei Liu;P. Sen
中科院分区：
文献类型：
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作者：
Zhiyuan Hu;Ya-jie Qiu;Yanfei Liu;P. Sen
LLC转换器在大电流应用中面临挑战，其中高传导损耗限制了最大负载容量并降低了效率。交错并联技术可以解决这一问题，但谐振回路的元件容差会导致严重的负载分配问题。提出了SCC-LLC变换器来解决负载分配问题。然而，由于其恒定的开关频率操作，与传统的LLC转换器相比，它在整个线路和负载变化方面具有一些限制。在本文中，提出了一种新的控制策略的SCC-LLC转换器，使可变开关频率操作，因此，它提供了不折不扣的性能，同时实现交错操作。给出了分析和设计方法，并搭建了一台600 W的两相交错并联SCC-LLC样机，验证了该方案的可行性。
LLC converters face challenges in high-current applications, where the high conduction loss limits the maximum load capacity and reduces efficiency. Interleaving technique can be used to solve this problem, but the component tolerances of the resonant tanks will cause severe load sharing problem. The SCC-LLC converter was proposed to solve the load sharing problem. However, due to its constant switching frequency operation, it has some limitations over complete line and load variation compared to conventional LLC converters. In this paper, a new control strategy is proposed for the SCC-LLC converter, which enables variable switching frequency operation; thus, it provides uncompromised performance while achieving interleaved operation. Analyses and a design method are provided, and a 600-W two-phase interleaved SCC-LLC prototype is built to verify the feasibility.