用于电动汽车充电的部分功率处理LLC变换器

Partial Power Processing LLC Converter for Electric Vehicle Charging

  • 摘要: 随着电动汽车的普及,电动汽车充电桩的需求不断增加。目前,家庭或办公场所主要采用交流充电方式,然而,其主要缺点是充电时间较长,通常需要4~20 h,不利于电动汽车的推广和发展。为解决这一问题,提出了一种基于LLC谐振变换器的充电桩设计方案。该拓扑采用部分功率处理的结构,允许充电桩将大部分功率直接传输到电动汽车,而只有少部分功率经过变换器处理后再传输到电动汽车。这种设计有效地减少了中间环节的功率损耗,提高充电效率。对部分功率处理的连接方式进行分析选择,对拓扑的参数和控制策略进行讨论。最后通过Matlab/Simulink仿真验证控制策略的可行性,通过搭建一个等比例缩小的硬件试验平台进行试验,验证当通过全桥LLC谐振变换器的功率仅为额定功率的一部分时,变换器仍能输出稳定的功率,证明了所提拓扑的有效性。将部分功率处理的LLC和全功率处理的LLC在相同工况下进行比较,证明了在全电压增益范围内,所提拓扑均能实现效率提升。部分功率变换器仅处理35%功率时,满载效率提高0.8%,在50%负载时效率提高了1.5%。

     

    Abstract: With the popularization of electric vehicles, the demand for electric vehicle charging piles is increasing. Currently, AC charging is mainly used in homes or offices, however, its main drawback is the long charging time, which usually takes 4~20 h, which is not conducive to the promotion and development of electric vehicles. In order to solve this problem, a charging pile design scheme based on LLC resonant converter is proposed. The topology adopts a partial power processing structure, which allows the charging pile to transmit most of the power directly to the electric vehicle, while only a small portion of the power is processed by the converter and then transmitted to the electric vehicle. This design effectively reduces the power loss in the intermediate links and improves the charging efficiency. The connection method of partial power processing is analysed and selected, and the parameters of the topology and the control strategy are discussed. Finally, the feasibility of the control strategy is verified by Matlab/Simulink simulation, and the effectiveness of the proposed topology is proved by building an equally scaled-down hardware experimental platform for experiments, which verifies that the converter still outputs stable power when the power passing through the full-bridge LLC resonant converter is only a part of the rated power. The partial power treated LLC and the full power treated LLC are then compared under the same operating conditions, proving that the proposed topology achieves efficiency improvement over the full voltage gain range. The partial power converter handles only 35% power with 0.8% efficiency improvement at full load and 1.5% efficiency improvement at 50% load.

     

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