基于LCL滤波器的光伏并网逆变器研究

摘要

光伏并网发电系统采用LCL滤波器有利于抑制开关谐波电流进入电网，改善电网的电能质量，但是LCL滤波器增加了系统的阶数，易发生谐振在谐振频率处产生很高的谐振尖峰。提出了有源阻尼双闭环并网控制策略，电感电流外环电流控制并网电流和功率因数，通过电容电流内环来增加系统的阻尼，抑制系统的谐振。推导了系统的传递函数，分析了控制参数对系统闭环极点分布和稳定性的影响，并提出LCL滤波器参数设计方法。仿真和实验结果验证了所提控制策略的可行性。%Photovoltaic grid power generation system using LCL filter is helpful for restraining harmonic current into the grid, Improve the power quality of power grid, but LCL filter increases, the order of the system is easy to happen at the resonant frequency to produce high resonant peak. Active damping double closed- loop grid- connection control strategy is proposed, inductor current loop current control grid, current and power factor by capacitive current environment to increase the system damping, inhibit the resonance of the system. Derivation of the system trans-fer function analysis of the control parameters of the system closed- loop poles distribution and stability, and proposed LCL filter parameter design method. Simulation and experimental results verify the feasibility of the proposed control strategy.