并网型逆变电源LCL滤波器的优化设计

Optimal Design of LCL Filter for Grid-connected Inverter

近年来,在对可再生能源进行利用的过程中,逆变器担负着能量转换和控制的任务,逆变器属于开关器件,在能量转换过程中会产生大量谐波。由于LCL型并网逆变器拥有较好的滤波性能,因此广泛应用于高压大功率场合。本文基于电流闭环的前馈解耦控制方案,通过PI控制,设计了三相并网逆变系统。选用LCL滤波器进行并网逆变系统的滤波,构建并网逆变器的数学模型,并对参数进行设计,将LCL滤波器的各个参数进行精确量化。选用有源阻尼法来增加系统阻尼,利用自控原理的等效原则,在控制方法中加入一个等效电阻取代电路中的实际电阻,抑制谐振。利用Simulink模块搭建三相并网逆变器仿真模型,在理想电网下对三相并网逆变器仿真模型进行稳态和动态分析,验证设计方案的合理性。

In recent years, in the process of utilizing renewable energy, the inverter is responsible for energy conversion and control. The inverter is a switching device, which generates a large number of harmonics during the energy conversion process. Because LCL type grid-connected inverter has better filtering performance, it is widely used in high voltage and high power applications. In this paper, based on the current closed-loop feedforward decoupling control scheme, a three-phase grid-connected inverter system is designed by PI control. The LCL filter is used to filter the grid-connected inverter system, the mathematical model of the grid-connected inverter is constructed, and the parameters are designed to accurately quantify the parameters of the LCL filter. The active damping method is used to increase the system damping. By using the equivalent principle of the self-control principle, an equivalent resistance is added to the control method to replace the actual resistance in the circuit to suppress the resonance. The Simulink module is used to construct the three-phase grid-connected inverter simulation model. The steady-state and dynamic analysis of the three-phase grid-connected inverter simulation model is carried out under the ideal power grid to verify the rationality of the design scheme.