光伏发电系统中高升压比DC-DC变换器

摘要

Photovoltaic(PV) generation system is an important application for the use of solar energy and attracts more and more attention. It usually contains a former DC-DC converter and an afterward inverter. Single-phase inverter output voltage is typically 220 V(AC), so the former DC-DC converter need to reach a high step-up ratio, which is out of the capability of the single-stage converter. A two-stage structure with a Boost converter and a full-bridge converter is used in this paper. Moreover, the LLC resonant network is introduced to the full-bridge converter for the further improvement of performance. Two 1 kW prototypes of DC-DC converter are built in the lab for comparison. The experimental results verify the theoretical analysis and satisfy the design requirements.%光伏发电作为太阳能的重要应用方式正受到越来越广泛的关注,普遍采用前级DC-DC变换和后级逆变的结构.单相逆变器的输出电压通常为220 V(AC),这就要求首级DC-DC变换器具有很高的升压比.由于单级式DC-DC变换器难以满足要求,本文采用Boost变换器加ZVS全桥直流变压器的两级式结构.针对ZVS全桥直流变压器的不足,将LLC谐振网络应用于全桥直流变压器电路,提出了一种全桥LLC谐振直流变压器,从而实现整个负载范围内开关管的ZVS和整流二极管的ZCS.最后,分别制作了两台1 kW的原理样机进行实验验证,实验结果验证了理论分析的正确性.