光伏并网逆变中全桥LLC谐振技术的应用

Application of Full-bridge LLC Resonant Technology in PV Grid-connected Inverter

传统家庭式光伏并网逆变器中的升压电源多采用脉宽调制（PWM）硬开关推挽升压技术．存在开关损耗大、转换效率低以及故障率高等缺点。针对上述问题，提出一种在家庭式光伏升压电源中应用全桥LLC谐振软开关技术的方法。分析了全桥LLC变换器中谐振元件的参数和变压器的设计：通过Saber仿真验证了理论参数的可行性；最后研制了一台250W基于全桥LLC谐振结构并采用脉冲频率调制（PFM）的家庭式光伏升压电源样机。实验结果表明，该电源样机输入电压为20—40v可调，输出电压可恒定为360V；在整个输入电压范围内均实现了开关管的零电压开关（ZVS）。所提升压电源提高了光伏升压电源的效率。同时满足了节能减排要求。

The Boost power source of the traditional family type PV inverter mostly uses the pulse width modulation （PWM） hard-switching push-pull Boost technology.There are so many issues of big switch loss ,low conversion efficiency,and high failure rate,ere.Aimed at these disadvantages,this paper describes the application of the full-bridge LLC resonant technology soft-switching technology.Firstly, the design of the resonant component parameters in the full- bridge LLC inverter and the transformer is analyzed.The feasibility of the theoretical parameters is verified by Saber simulation.Finally,a 250 W experimental prototype based on the full-bridge LLC resonant structure and pulse frequency modulation （PFM） modulation is developed.The experimental results show that the input voltage of the power source is adjustable （20-40 V） and the output voltage is constant（360 V）.The switch tubes zero voltage switching （ZVS） is achieved in the entire input voltage range.The efficiency of the PV boost power source is improved.