基于BOOST-BUCK变换器的低压控制系统
摘要:本文从提高光伏发电系统整体效率的角度出发,以光伏发电系统中电能变换装置作为研究对象,研究光伏发电中的关键技术环节之一 ——光伏阵列的最大功率跟踪点技术。主要研究适用于光伏发电系统的最大功率跟踪变换器的拓扑;研究光伏发电系统的最大功率点跟踪变换器的控制方法。本文在分析研究了几种基于DC/DC变换器的最大功率跟踪算法及各自优缺点和适用场合。在拓扑研究方面,分析研究了Buck、Boost和Boost-Buck电路应用于光伏发电中的优缺点以及适用的最佳功率等级,并对这三种电路的功率损耗进行分析,通过仿真实验进行验证。探讨了把软开关技术、三电平技术应用于光伏发电的可行性,并详细分析了应用于光伏发电系统的Boost-Buck DC/DC变换器电路的换流过程。在理论分析的基础上,将传统的Buck变换器与Boost变换器相结合,采用变换器结合的方式,研究了一种双开关Boost-Buck变换器。该变换器根据输入输出条件,可分别工作于Boost模式,Buck模式和临界模式。与传统的Boost-Buck变换器相比较,具有正极性的输出电压和更宽的输入电压范围。仿真结果表明该电路性能良好。
关键字: 光伏发电系统 Boost-Buck变换器 DC/DC变换器 软开关 三电平
最大功率跟踪点
The low-pressure starting systems based on boost-buck topology
Abstract: In order to improve the overall efficiency of photovoltaic power generation system, these articles close the conversion devices as a researcher goal and did some researches on the key Technologies of photovoltaic power generation—the maximum power point tracking techno- -logy of photovoltaic array. It did some major researches on the topology applicable to the maximum power point tracking convector and on its control methods.Analyzing the principle and output characteristics of solar cells,this article introduced several maximum power point tracking algorithms based on the DC/DC convector and their respective advantages and dis- -advantages.On the topology research,this article analyzed the advantages and disadvantages of the Buck and Boost and BUCK-BOOST circuits when they were applied in the photovo- -ltaic power generation and summarized their best applicable power rating.Then it provedThe correctness of Theoretical calculation by simulation. Discussed the feasibility of the appl- -ication of soft-switch and three-level technology using in the photovoltaic power generation and detailed the converter process of the phase—BUCK-BOOST DC/DC converter. through the theoretical analysis,combine a traditional buck converter with a boost converter. The buck-boost converter includes a boost-voltage mode, a buck-voltage mode and a critical working mode in accordance with the input and output conditions. Compared with the tradi- -tional. buck-boost converter, its output voltage is positive and the input voltage ranges are wider. The simulation results prove that the buck-boost converter has good performance.
Keywords: PV generation system , buck-boost converter, DC/DC convector, soft-switch, three-level technology, the maximum power point tracking