基于传统直接功率控制的策略思想,改变以L电感并入电网的拓扑结构,提出基于LCL滤波器的直接功率控制,系统分析有源阻尼,谐波抑制,虚拟磁通估计和锁相环PLL等控制算法,进而提出改进的直接功率控制策略.在MATLAB/SIMULINK的仿真平台上,分别搭建光伏并网的主电路模型,以及包含有源阻尼,谐波抑制,虚拟磁通估计和PLL模块的统一协调的控制系统,仿真结果表明改进的直接功率控制能有效改善并网逆变器的电流质量,降低总谐波畸变率,并使电网电压和注入电网电流同相,功率因数为1.%Based on the concept of conventional direct power control, the topology with L filter connected to power grid is changed in this paper. The direct power control based on LCL filter is proposed, and after the control algorithms such as active damping, harmonic suppression, virtual flux estimation and phase lock logic etc are systematically analyzed, an improved direct power control strategy is put forward. Based on the simulation environment of MATLAB/SIMULINK, a main circuit mudel of photovoltaic grid-connected, and a unified and coordinated control system including active damping, harmonic suppression, virtual flux estimation and PLL etc are built respectively. The simulation results show that the proposed direct power control can improve the current quality of the grid-connected inverter effectively, decrease the total harmonic distortion, and help the power grid voltage to synchronize with the injected current with the power factor being 1.
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