基于半桥LLC谐振变换器的电动客车充电设备的研究

Research on Electric Bus Charging Equipment Based on Half Bridge LLC Resonant Converter

电动客车充电设备的开关电源通常采用谐振变换器作为DC-DC隔离型拓扑结构,传统的LC串联、LC并联或LCC串并联谐振变换器在输入电压波动较大情况下存在较大关断电流,因此,基于半桥LLC谐振变换器的电动客车充电设备,采用基波近似法分析品质因数、电感比等参数对变换器直流增益的影响,研制了充电设备样机,对电动客车蓄电池进行了多阶段充电策略的状态控制测试,结果表明基于半桥LLC谐振变换器的电动客车充电设备具有优异的软开关性能,有效地提升了设备直流输出电压的质量。

Under the vision of energy saving and emission reduction in public transportation, electric buses have a broad development market. The switching power supply of the electric bus charging device usually adopts a resonant converter as a DC-DC isolated topology. The conventional LC series, LC parallel or LCC series-parallel resonant converter has a large off current when the input voltage fluctuates greatly. Therefore, the electric bus charging equipment based on half-bridge LLC resonant converter is studied. The influence of quality factor and inductance ratio on the DC gain of the converter is analyzed by the FHA (first harmonic approximation) method. The prototype of the charging equipment is designed and developed for the electric bus battery. The state control test of the multi-stage charging strategy shows that the electric bus charging device based on the half-bridge LLC resonant converter has excellent soft switching performance and effectively improves the quality of the DC output voltage of the device.