基于电流解耦控制的光伏并网系统仿真分析

光伏并网发电是太阳能利用的重要途径,而并网逆变器结构的选择和控制策略的改进是其研究的重点。在PSCAD/EMTDC平台上搭建了单级三相光伏并网系统的仿真模型,仿真模型中的并网逆变器采用双闭环的控制策略,其中电流内环根据非线性控制理论中反馈线性化的思想,实现电流的解耦控制,电压功率外环采用PI控制。仿真结果表明:该控制策略不仅控制精度高,稳定工作域大,并且必要时能在一定范围内对配网的无功进行调节,提高配网稳定性。

Simulation analysis of a grid-connected PV system based on current decoupled controlling

Grid-connected photovoltaic（PV） system is considered as an important part of the solar energy.Aiming at grid-connected inverter＇s structure and control strategy of PV systems,a single-stage three-phase grid-connected PV system with double closed-loop controlling was established in PSCAD/EMTDC.According to the theory of the feedback linearization of nonlinear system,a current decoupled controller based on input-output variable feedback linearization was designed as current inner loop,PI controllers were used in the outside loop.The simulation results verify that the control strategy has high control accuracy,great stability domain.Meanwhile,the grid-connected PV systems can regulate reactive power in certain range to improve the stability of distribution network.