太阳能是重要的可再生能源之一，近几年来光伏发电产业发展迅猛。其中光伏并网发电已经成为光伏发电的主流趋势。作为并网发电系统能量转换与控制核心装置的光伏并网逆变器成为电力电子行业研究和开发的热点。由于光伏并网逆变器的容量较大，为了降低系统损耗，一般采用较低的开关频率。若采用L型滤波器连接逆变桥和电网，则需要较大的电感值，增加了体积和成本，降低了控制的响应速度。所以在比较大的功率等级的并网逆变器系统中，通常采用LCL型滤波器来代替L型滤波器。 本文针对基于LCL型滤波器的三相光伏并网逆变器，开展了以下研究工作： 首先，分析了三相光伏并网逆变器的拓扑结构，选择三相全桥逆变拓扑作为主要的电路拓扑结构；推导了基于L型、LC型和LCL型滤波器的三相光伏并网逆变器的状态空间数学模型；对逆变器的两种调制技术进行比较分析，重点阐述了空间矢量脉宽调制的原理，并在Matlab中的Simulink平台进行了仿真模型的搭建。 其次，采用电网侧电感电流和电容电流的双闭环控制策略，在分析重复控制与双环PI控制的互补特性的基础上，将重复控制器与电流环并联以提高三相光伏并网逆变器的稳态性能，设计了基于电网电压定向的复合控制方案。 然后，利用Matlab中的Simulink平台搭建了三相光伏并网逆变器的仿真模型，通过仿真实验，验证了引入重复控制的复合控制方案能够进一步降低并网电流畸变，提高并网电流波形质量。 最后，设计了三相光伏并网逆变器样机的硬件系统，包括主电路中主要元器件的参数设计和以TMS320F2812为主控芯片的控制电路中的信号采样电路和功率驱动电路的设计，为进一步的样机实验打下了基础。

The solar energy is one of the most important renewable energy, and photovoltaic industry has developed rapidly in recent years. The grid-connected power generation has become the main trend of photovoltaic power generation. As the core device of energy conversion and control for grid-connected power system, the photovoltaic grid-connected inverter is becoming a hot spot research and development in power electronics industry. Due to large capacity of photovoltaic grid-connected inverter, generally the lower switch frequency is used in order to reduce system loss. If an L filter connects an inverter bridge to the grid, large inductance value is required, which increase the bulk and cost and reduces the response speed of control. So in the high power grid-connected inverter system, the LCL filter usually replaces the L filter. In this paper, the main work is as follows for the three-phase photovoltaic grid-connected inverter based on the LCL filter. Firstly,the topology of the three-phase photovoltaic grid-connected inverter is analyzed, and the three-phase full bridge inverter topology is selected as the main circuit topology; The state space mathematical model of the three-phase photovoltaic grid-connected inverter based on L filter is deduced as well as LCL filter. The two inverter modulation technology is compared and the principle of space vector pulse width modulation is expounded particularly. Secondly,the double loop control strategy with the inductor current of grid side and capacitor current is used, and the basic principle and internal structure of repetitive control is analyzed .Repetitive controller is paralleled to the double current loop to improve the steady state performance of the three-phase photovoltaic grid-connected inverter on the basis of the complementary characteristics of repetitive control and double loop PI control, forming a compound control strategy based on grid voltage orientation. Then,Simulation models for the system are set up in Matlab platform. The results of simulation experiments verify this compound control strategy with repetitive control can further reduce the grid current distortion and improve the quality of grid current waveform. Finaly,the three-phase photovoltaic grid-connected inverter prototype hardware system is designed, including the parameter design of the main components in the main circuit and the signal sampling circuits and driver circuit in control board with main control chip TMS320F2812.These lay a foundation for further prototype experiments.