光伏并网逆变器的LCL滤波器效率优化

Efficiency Optimization of LCL Filter for Grid-connected Photovoltaic Inverter

为了提高光伏发电系统的并网效率,降低并网谐波,根据模拟滤波器的理论和设计方法,指出LCL滤波器的优势所在。结合逆变器应用详细介绍了LCL滤波器主要参数的设计优化方法,对滤波器主要器件的损耗计算和效率优化做了量化分析。将滤波器与实际300 kW光伏逆变器连接试验,仿真和试验结果验证了设计的正确性,根据实验结果绘制的负载-效率曲线在50%负载和100%负载时滤波器电能转换效率均在99%之上,电流总谐波畸变率THD在100%负载时小于1%,均大大优于各国际、国内标准和技术规范的要求。

In order to improve the power efficiency and reduce the harmonic of grid-connected photovoltaic （PV） inverter system, the advantages of LCL filter were pointed out based on design theory of analog filter. Combined with the application of inverter, the design optimization method of main parameters of LCL filter was introduced in detail as well as the losses calculation of main components in the filter, and its quantitatively analysis regarding efficiency improvement. The design-optimized LCL filter was tested after connecting to real 300 kW PV inverter and power network. The result of simulation and test verified the optimization. The load-efficiency curve which based on the test result displayed the efficiency of filter reaching more than 99% with 50% and 100% load, the total harmonic distortion （THD）of current less than 1% which is much better than the requests from standards and norms.