Project supported by National Natural Science Foundation of China(51577019)
在无需变压器隔离的光伏并网发电系统中，在光伏电池和并网逆变器之间须采用非隔离DC/DC变换器完成高增益变换。为此，提出了一种高增益软开关直流变换器，在相同电压增益条件下，其相对于传统升压变换器具有占空比更低、开关损耗更小、电压应力更低的优势。在分析变换器工作原理的基础上，对其性能进行了详细分析，最后搭建了一台48 V输入、380 V输出、额定功率为250 W的试验样机，实测最高效率为92.48%，实验结果验证了理论分析的正确性。
In a transformer-less photovoltaic(PV) grid-connected power generation system, the transformation with a high voltage gain is realized by means of a non-isolated DC/DC converter between the PV cell and the grid-connected converter. In this context, a high-gain soft-switching DC/DC converter is proposed in this paper. Compared with the conventional Boost converter, this converter has advantages of a lower duty cycle, a smaller switching loss, and a lower voltage stress under the same voltage gain condition. Based on the analysis of the operating principle for the proposed converter, its performance is analyzed in detail. Finally, a 250 W prototype with 48 V input and 380 V output was built, and its highest measured efficiency was about 92.48%. Experimental results verified the correctness of the theoretical analysis.