一种带开关电容的二次型高增益Boost变换器的研究

光伏、燃料电池等发电系统的输出电压等级较低且输出电压不稳定,需要通过高增益Boost变换器把较低等级的直流电压进行升压以满足并网要求。提出一种带开关电容的二次型高增益Boost变换器,在传统二次型Boost变换器的基础上引入开关电容单元,提高了变换器的升压能力,实现了以较小的占空比获得较大的电压增益,拓宽了输入电压范围。同时,该变换器改进了传统二次型Boost变换器开关管和二极管电压应力过大的缺点,减小了开关管的导通损耗和二极管的反向恢复损耗。另外,该变换器还有输入电流连续、输出电压纹波小的优点。分析了该变换器的工作原理及工作特性,在理论研究的基础上搭建了一台12 V/60 V的实验样机,实验结果证明了理论分析的正确性。

Research on Quadratic High-gain Boost Converter with a Switched-capacitor

The output voltage level of the solar energy and fuel cell power generation system is low. Moreover the output voltage is unstable. In order to meet the requirements, high step-up converters are need to boost the low level DC voltage. This paper proposed a Quadratic high step-up boost converter with a switched-capacitor. The switched-capacitor cell is introducted on the basis of a conventional quadratic high step-up boost converter secondary. Compared with previous high step-up voltage gain converters, the novel converter provides a higher voltage conversion ratio and can get higher voltage gain under a small duty ratio, and is suitable for application of wide input voltage. At the same time, the novel converter proposed in this paper improves the shortcomings of high voltage stresses of switch and diodes over the conventional quadratic boost converter, hence the switching loss and conduction loss. In addition, the converter proposed in this paper has the advantages of the continuous input current and small output voltage ripple. This paper analyzes the working principle and Operating Characteristics of the proposed converter. A prototype with 12 V-input and 60 V-output was built and the experimental results verify the correction of the theoretical analysis.