新型微型光伏并网逆变器的分析与实验

Analysis and Experiment of Novel Micro Photovoltaic Grid-connected Inverter

微型光伏并网逆变器具有高可靠性、可模块化等优点。针对一种新型的微型光伏并网逆变器(T型三电平逆变器)进行研究,分析其在边界电流导通模式(BCM)下的工作原理和中点电位不平衡原因,提出均压调制策略;采用自适应复位电流控制方法,优化了逆变器的效率,同时解决了轻载条件下开关频率过高的问题;搭建了一台300 W实验样机,实验结果验证了控制策略的可行性,提高了逆变器的效率。

The micro photovoltaic grid-connected inverter has the advantages of high reliability and modularity.A novel micro photovoltaic grid-connected inverter(T-type three-level inverter)is researched.Operation principle of the inverter in boundary conduction mode(BCM)is analyzed,and a modulation strategy of voltage balance is prerented.An adaptive reset current control method is adopted to improve the efficiency and solve the problem of excessively high switching frequency under light load condition.A 300 W prototype is built,and the feasibility of the control strategy is verified and the efficiency of the inverter is improved by the experimental results.