随着社会的发展，煤、石油、天然气等非可再生能源短缺以及其过渡使用而引发的环境问题日益突出，大力发展低污染、可再生的新能源已成为世界各国的共识。其中太阳能以其清洁、资源丰富等优点而更受到各国政府的青睐。但是目前发电成本较高是制约太阳能发展的一大瓶颈，而通过有效的控制以提高太阳能的利用率来降低光伏发电成本一直是太阳能发电领域研究的重要课题之一。本文针对这一问题对离网光伏发电系统进行了深入的研究。 文中所设计的光伏发电系统选用DC/DC和DC/AC两级逆变结构。DC/DC采用Boost升压电路完成光伏最大功率点(MPP)的跟踪；DC/AC采用基于SPWM的双闭环控制理论完成逆变功能。 首先，通过建立光伏电池的仿真模型，在分析光伏电池输出特性和定步长扰动观测法的误判与震荡问题的基础上，提出了一种改进的最大功率点跟踪(MPPT)控制方法，并以Matlab/Simulink为平台搭建仿真模型，对该算法的最大功率点跟踪效果进行了验证。 其次，分析了SPWM的调制方法，建立了单相全桥逆变电路的数学模型并进行了分析。深入研究分析了电压外环电流内环的逆变器双闭环控制策略，在设计中电压外环采用PI调节器，电流内环采用P调节器，并采用极点配置法对双闭环逆变控制系统的参数进行了整定。 最后，在上述理论研究和仿真的基础上，以TI公司的TMS320F2812作为控制核心，对小功率离网光伏发电系统的软硬件系统进行了设计。结合实验室条件搭建了实验平台，从相关实验电路的调试结果中可以看出，所设计的电路实现了各部分的功能，验证了所设计软硬件系统是合理的。

With the development of society, coal, petroleum, natural gas and other fossil energy shortage and environmental problems caused by the use of fossil energy have become increasingly prominent, and developing less pollution, renewable energy has become the consensus of the world. In all of the new energy resources, solar energy is more favored by governments , because the solar energy has the advantages of clean and widely distributed. But the cost is too high is the biggest obstacle to the development of solar energy, and through effective control to improve the utilization of solar energy has been an important task in the field of solar power to reduce the cost of photovoltaic power generation. About this problem, this paper conducted in-depth study of off-grid photovoltaic power generation system. Photovoltaic power generation system is designed in this paper useing DC/DC and DC/AC two level inverter. The DC/DC uses boost circuit to complete photovoltaic maximum power point tracking (MPPT),and the DC/AC part based on SPWM double closed loop control theory to realize the inverse function. First of all, established simulation model of photovoltaic cells, On the basis of analysis of photovoltaic cell output characteristic curve and the misjudgment and oscillation problems of fixed step disturbance observer method, an improved maximum power point tracking (MPPT) control method is proposed. And then build the simulation model in the Matlab/Simulink environment to verify the improved method. Then, analyzes the modulation method of SPWM, established the mathematical model of single-phase full-bridge inverter circuit and analysis. In-depth analysis of the double closed loop control strategy of inverter voltage outer loop current loop, voltage in the design loop with PI regulator, current inner loop P regulator, and the parameters of the double closed loop control system are set by pole placement method. Finally, based on the theory study and simulation, using TI's TMS320F2812 as the control chip, the power from the hardware and software system of photovoltaic power generation system is designed. Combined with laboratory conditions to build an experimental platform, from the test results can be seen in the experimental circuit, the circuit design to realize the function of each part, validate the rationality of design.