基于改进滑模控制的光伏并网逆变器控制策略

Control Strategy for PV Grid-connected Inverter Based on Improved Sliding Mode Control

针对直流侧和网侧不确定干扰对光伏并网逆变器控制性能造成影响的问题,提出了一种改进双闭环滑模控制策略。外环选取直流侧电压为状态变量,采用积分滑模控制,以减小系统稳态误差;基于趋近律函数对系统控制特性的影响,内环滑模控制中引入一种新型的趋近律,削弱了抖振。在MATLAB/Simulink平台上进行了仿真分析。结果表明,所提出的控制策略在使光伏发电系统稳定运行的同时,有效提升了系统的动态性能,降低了入网电流谐波畸变率,并可使系统保持较强的抗干扰能力。

An improved dual closed-loop sliding mode control strategy is proposed to improve the control performance of PV grid-connected inverters due to uncertain interference from DC side and grid side.The outer loop adopts integral sliding mode control to reduce the steady-state error of the system,and the DC voltage is selected as the state variable.Based on the influence of reaching law function on the control characteristics of the system,a new type reaching law is introduced into the inner loop sliding mode control to reduce chattering while ensuring the response speed of the system.Finally,simulation analysis is carried out in MATLAB/Simulink platform,and the results show that the designed control strategy can effectively improve the dynamic performance of the system,reduce the harmonic distortion rate of the incoming current,and maintain the system with strong anti-interference capability under the premise of making the PV power generation system operate stably.