基于粒子群的三电平并网逆变器LCL滤波参数的高效精确设计方法

Efficient and Accurate Design Method of LCL Filter for Three-level Grid-connected Inverter Based on Particle Swarm Optimization

LCL滤波器性能主要取决于LCL参数的设计,试凑法是LCL参数设计的传统方法,其效率较低且难以获得同时满足约束和校验条件时的最佳参数。同时,由于缺少对逆变器输出电压谐波的详细分析,故得到的LCL参数过于保守致使滤波器体积过大,或其高频滤波性能不够理想。基于上述问题,该文以层叠载波调制的三电平并网逆变器为研究对象,首先,通过二重傅里叶级数对逆变器输出电压谐波进行详细分析,构建包含入网电流高频谐波畸变率和价值函数等在内的多目标优化函数;其次,提出一种基于筛选法和粒子群算法的LCL参数设计方法;最后,通过仿真和实验验证谐波分析和LCL参数设计方法的有效性。

The performance of LCL filter mainly depends on the design of LCL parameters. The trial and error method is a traditional method for LCL parameters design, which has low efficiency and it is difficult to obtain the optimal parameters which meet both the constraints and verification conditions. Furthermore, due to the lack of detailed analysis of inverter output voltage harmonics, the LCL parameters obtained are too conservative, resulting in too large filter size, or its high-frequency filtering performance is not ideal. Based on the above problems, the three-level grid-connected inverter with cascaded carrier modulation was taken as research object in this paper. Firstly, the output voltage harmonics of the inverter were analyzed in detail through the double Fourier series, then the multi-objective optimization function including the high-frequency harmonic distortion rate of the grid-connected current, cost function, etc. was constructed. Secondly, a design method of LCL parameters based on the screening method and particle swarm optimization was proposed. Finally, the effectiveness of harmonic analysis and LCL parameters design method was verified by simulation and experiment.