中文摘要：

为改善光伏并网逆变器控制系统的动态性能，根据并网逆变器数学模型，提出利用指数滑模变结构控制律和平方根滑模控制律，设计基于改进滑模变结构的单相电流环光伏并网逆变器控制系统。推导了滑模变结构控制在并网逆变器应用的滑模面存在性，并利用李亚普诺夫定理证明了系统稳定性。针对所选滑模控制律存在的非线性可能引起系统抖振的问题，采用单位控制连续化方法，使改进后的控制算法在切换面附近具有高增益特性，使系统具有抵抗干扰和参数摄动的能力。最后对2种控制方法进行了比较，证明改进的指数滑模变结构有更精准的跟随特性。

英文摘要：

According to the mathematical model of grid-connected inverter, the exponential sliding mode control law and square root sliding mode control law are used to improve the dynamic performance of gridconnected PV inverter control system, and a grid-connected PV inverter control system with single-phase current loop is designed based on modified sliding mode variable structure. The existence of sliding surface in the variable structure control of grid-connected inverter is deduced, and the system stability is proven by Lyapunov theorem. As the nonlinearity of the chosen sliding mode control law may cause the system buffeting, the continuous unit control method is adopted to increase the gain of control algorithm nearby the switching surface, enhancing the system capability against disturbance and parameter perturbation. Comparison of two control strategies shows that the modified exponential sliding mode variable structure provides better control precision and follow-up characteristics.