中文摘要：

为了实现单相光伏逆变器交流并网电流的无静差输出，获得良好的并网性能，提出一种基于δ算子（Delta 算子）实现广义二阶积分（SOGI）的单相同步旋转坐标系并网电流数字控制策略。运用二阶广义积分器，使单相电网电压与并网电流产生90°相移，得到α、β正交坐标系下的电压电流矢量，并构造出单相同步旋转坐标系。实现了基于同步旋转坐标系的单相电网电压数字锁相环控制与并网电流的无静差输出控制。与基于移位算子q的Z变换数字实现方法相比，在快速采样情形下离散模型更能趋近于连续模型，避免了SOGI幅值和相移的误差以及Z变换引起的数值不稳定等问题。仿真与实验结果证明了理论分析的可行性，系统具有良好的并网性能。

英文摘要：

In order to eliminate the steady-state error of AC output connected performance, implementing digital control strategy of grid integral （SOGI） single-phase synchronous rotating coordinate system algorithm, making orthogonal of single-phase PV inverter and get connected current in secondary order a good grid generalized based on δ operator was put forward. Using SOGI single phase voltage and current produced the 90° phase shift, and voltage and current vectors in α-β frame were obtained, and single phase synchronous gyral frame was created accurately. Then single phase PLL control and grid current control without steady-state error were achieved based on synchronous gyral reference frame. Comparing with the digital implementation of Z transform based on the shifting operator q, the discrete model in a fast sampling situation could approximate to continuous model. The errors of amplitude and phase shift in SOGI was avoided, also the numerical value instability problems caused by the Z transform. The simulation and experimental results prove that theoretical analysis is feasible and system has good grid connected performance.