LCL滤波并网逆变器的电流控制技术研究综述

并网逆变器是新能源发电、微电网等与大电网之间的接口电路,其进网电流质量控制是关键技术之一。LCL滤波的并网逆变器可有效地抑制进网电流中的开关频率次谐波电流,但其高阶属性导致的谐振问题易使进网电流发生振荡而控制困难,是目前各国学者广泛研究的课题。针对LCL滤波并网逆变器的电流控制技术,从滤波器谐振现象及其抑制策略、电流准确跟踪控制以及电网适应性等方面分析并评述了现有的典型控制方案。最后,指出了LCL滤波并网逆变器电流控制需要进一步研究的问题。

Overview of Current Control Strategy for Grid-Tied Inverters with LCL Filters

Grid-tied inverters are the commonly-adopted interface between renewable energy power generation, micro-grid and the utility. The control of injected grid current is one of the key technologies. Generally, with LCL-type filter, the switching harmonics in injected grid current can be effectively eliminated. However, current is easily resonated because of the resonance phenomenon associated with the high-order filter. Consequently, the design of the control is difficult and has been concerned all over the world. In this paper, an overview of the current control for grid-connected LCL-filtered inverters is presented and evaluated. It consists of resonance phenomenon and its rejection strategy, precise tracking control and grid applicability control. Furthermore, the prospect research focuses for grid-tied LCL-filtered inverters are given.