燃料电池系统宽范围输入电压变换器设计

燃料电池输出特性较软使得其系统中单向DC/DC变换器需要较宽的输入电压,从而限制了该变换器的应用。文章利用双管Buck-Boost级联电路可根据输入电压的大小自动切换升/降压工作状态来获得合适的恒定的输出电压的优点,对该级联电路设计了基于平均电流控制的电压、电流双闭环控制环路,从而实现其在宽范围输入电压下得到恒定的输出电压,可为燃料电池系统后级变换器提供稳定的输入电压,并降低其设计和优化的难度,还有效解决传统单管Buck-Boost电路开关管电压应力过高的问题。仿真和小功率样机的实验研究验证了所提采用双闭环控制环路的升降压变换器在宽范围输入电压下均具有良好的性能。

Design of wide-range input voltage converter in fuel cell system

The wide-range input voltage for unidirectional DC/DC converter in fuel cell system will be caused by soft output characteristic of fuel cell,which limits the applications of the DC/DC converters.The dual switch Buck-Boost cascaded circuit can automatically change the Buck or Boost working mode according to the input voltage to acquire proper constant or adjustable output voltage,the dual voltage/current close-loop control circuit based on the average current control has been designed for this circuit in this paper,in order to realize the dual switch Buck-Boost cascaded circuit acquire constant output voltage during wide-range input voltage,which can provide stable input voltage for later stage converter in fuel cell system to decreases the difficulties in design,optimization of later stage converter,and effectively solve the high voltage stress in conventional single switch Buck-Boost circuit.Simulation results and experiment research with low power prototype verify the excellent performance of dual switch Buck-Boost cascaded circuit with the proposed dual close-loop control circuit during wide-range input voltage.