基于准Z源与开关电容的高增益三端口变换器

A High Step-up Three-port Converter Based on Quasi-Z Source and Switched Capacitor

针对光伏、燃料电池等新能源混合供电系统输入电压低、范围宽等问题,提出了一种基于准Z源与开关电容的高增益三端口变换器。变换器3个端口分别连接新能源、蓄电池和负载,实现了3个端口之间的能量流动。采用准Z源结构限制开关管占空比,避免了开关管工作在极限占空比的情况,并且能够使变换器在较低的占空比下获得更高的电压增益。同时引入开关电容单元,提供额外的2倍电压增益,并且易于拓展。详细分析了所提变换器拓扑结构、工作原理以及稳态特性。最后,搭建了实验样机平台,实验结果验证了理论分析的正确性,该变换器可以在较低的占空比下获得较高的电压增益,同时具有良好的动态性能。

Addressing the issues of low input voltage and wide input range in new energy hybrid power supply systems,such as photovoltaic and fuel cells,a high step-up three-port converter based on quasi-Z source and switched capacitor is proposed.The three ports of the converter are connected to new energy,battery and load respectively,among which the flow of energy-is realized.The quasi-Z source structure is utilized to limit the duty cycle of the switch tube,which avoids the situation that the switch tube works at the limit duty cycle,and enables the converter to obtain a higher voltage gain at a lower duty cycle.Moreover,the switched capacitor unit is introduced to provide an extra 2times voltage gain and is easy to expand.The topological structure,working principle and steady-state characteristics of the proposed converter are analyzed in detail.Finally,an experimental prototype platform is constructed to verify the correctness of the theoretical analysis.Experiments show that the converter can obtain higher voltage gain at lower duty cycle and has good dynamic performance.