一种非隔离型高增益三端口DC-DC变换器

Non-isolated high step-up three-port DC-DC converter

针对光伏储能联合供电系统输出电压低、供电可靠性差等问题,提出了一种具备多种工作模式的非隔离型高增益三端口DC-DC变换器。变换器的3个端口共地,分别连接光伏发电单元、储能单元和负载,通过改进二次型结构提升电压增益,并降低开关器件应力。变换器具有5种工作模式,可满足离网光储发电系统的各种工况需求。此外,变换器对光伏端口和储能端口之间没有电压约束,能够适应更多的应用场合。详细分析了变换器在各工作模式下的工作原理和稳态特性,并与现有同类变换器进行了工作特性对比。根据光伏储能联合供电系统的控制要求和变换器在不同工况下的功率流动情况,研究了相应的模式运行与切换控制策略。最后,搭建了一台300 W的实验样机进行验证。

Aiming at the problems of low output voltage and poor power supply reliability of solar-storage combined power supply system,a non-isolated high step-up three-port DC-DC converter with multiple working modes is proposed.The three ports of the converter share the ground,which are respectively connected to the photovoltaic power generation unit,the energy storage unit and the load.The improved quadratic structure improves the voltage gain and reduces the stress of the switching device.The converter has five working modes,which can meet the requirements of various operating conditions of the off-grid solar-storage power generation systems.In addition,the converter has no voltage constraints between the photovoltaic port and the energy storage port,and is suitable for more occasions.The working principle and steady-state characteristics of the converter in each working mode were analyzed in detail,and the working characteristics were compared with the existing similar converters.According to the control requirements of the solar-storage combined power supply system and the power flow of the converter under different working conditions,the corresponding mode operation and switching control strategies were studied.Finally,a 300 W experimental prototype was built for verification.