基于重复多谐振的LCL并网逆变器复合控制策略

A Multiple Control Strategy for LCL Grid-connected Inverter Based on Repetitive Multi-resonance

在LCL型逆变并网系统中,谐波的出现会导致电力电子器件损耗、电机和变压器效率降低、电容器发热损耗以及干扰通讯控制系统等诸多危害。本文在分析LCL型并网逆变器拓扑结构之后,利用准PR控制可以实现无静差跟踪,以及重复控制可以抑制电网周期性扰动的特性,提出一种多谐振控制与重复控制级联的新型控制策略,通过设定谐波次数,更大程度降低并网电流中的谐波含量,实现无静差跟踪基波频率同时,改善并网电能质量,增强高频抗干扰能力,使得并网电流具有更好的稳态和动态性能。从理论和仿真实验方面验证了LCL逆变系统中新型控制策略对并网电流的控制作用以及对系统稳定性的影响。

In the LCL inverter grid-connected system,the occurrence of harmonics can lead to loss of power electronics,reduction efficiency of the motor and transformer,loss of capacitor heating and interference with communication control systems.After analyzing the LCL-type grid-connected inverter topology,this paper prevents the repetitive control based on multi-resonance control combining the advantage of the quasi-PR control which can realize the tracking without static tracking and the repeated control which can suppress the periodic disturbance of the grid voltage.The new control strategy of the joint reduces the harmonic content in the grid-connected current to a greater extent by setting the harmonic order,and tracks the fundamental frequency without static,and improves the power quality of the grid,and enhance the high-frequency anti-interference ability,the grid-connected current has better steady state and dynamic performance.From the theoretical and simulation experiments,the control effect of the new control strategy on the grid-connected current in the LCL-type inverter system and its influence on the stability of the system are verified.