随着社会的发展，能源短缺和生态环境恶化问题日益突出。发展低污染、可再生的新能源成为世界各国在21世纪能源战略的重点。太阳能以其清洁、资源分布均匀且丰富的优点，已成为各国政府发展新能源的热点，并且由于近年来光伏电池成本的降低，太阳能发电更是得到了迅速发展。光伏并网发电技术是太阳能发电的主要方向。本文深入研究了小功率并网系统的控制方法，并详细阐述了一套小功率光伏并网逆变系统的软硬件设计。 首先，本文介绍了光伏电池板的曲线特性，并建立了光伏电池板的仿真模型。通过对传统MPPT算法缺点的分析，提出了一种改进的新型算法，该算法可以有效的防止在外界光照发生变化时系统所产生的功率误判现象。 其次，对本文逆变控制器的控制方法做了详细的分析，选用电压电流双环控制。电压外环用于稳定逆变器直流母线电压，电流内环用于调节逆变器输出电流，并且采用数字锁相技术实时的检测电网电压的频率和相位，使得逆变器输出电流与电网电压同频同相。为防止电网电压变化对并网电流的影响，本文使用的电网电压前馈技术。 然后，针对本文所采用的两级式控制结构，搭建了硬件实验平台，它包括：前级DC/DC电路、后级逆变电路、模拟采样电路、驱动电路、保护电路等，并且对文章中的重要参数的选取方法做了详细的计算。 最后，基于DSP对MPPT模块和后级逆变电路模块做了软件编程，通过对电池板输出电压电流值和对逆变器输出电流电压的采集以及对电网电压信号的采样，将这些信号输入DSP中，在主程序中通过编程来完成MPPT功能和逆变器输出电流与电网电压同频同相功能。在最后给出了光伏并网系统的仿真图形和硬件输出波形，证明本文设计的算法和硬件电路是合理的。

With the development of society, energy shortages and the deterioration of ecological environment have become an increasingly prominent problem. To develop less polluting, renewable energy has become the focus of the countries energy strategy in the 21st century. The advantages of clean, evenly distributed, rich make solar energy become the focus of the countries in the development of new energy. And the decline in the cost of solar cells to make photovoltaic (PV) technology has been developing rapidly. Grid-connected PV technology is the main direction of solar power. This article studies the topology and control methods of the low-power photovoltaic grid-connected system, and elaborates the design of hardware and software in low-power photovoltaic grid-connected system. Firstly, the article describes the curve characteristics of the photovoltaic panels, and the establishment of the simulation model of the PV panels. Through the analysis of the drawbacks of conventional MPPT algorithm, proposed a new and improved algorithm, which can effectively prevent the phenomenon of the power generated by the system when the change in the external light misjudgment. Secondly, the controller of this inverter control method to do a detailed analysis, the choice of voltage and current double loop control. Outer voltage loop is used to stabilize the inverter DC bus voltage, the inner current loop is used to adjust the output current of the inverter, and the use of digital technology real-time detection of the frequency and phase of the grid voltage, such that the output current of the inverter and the grid voltage same frequency and phase. To prevent the grid current of the grid voltage changes, the article uses the grid voltage feed-forward technology. Then, for a two-stage control structure used in this paper, to build a hardware test platform, which includes: the previous level DC / DC circuit, after stage inverter circuit, analog sampling circuit, drive circuit, circuit protection, and articlethe important parameters for the selection of methods to do a detailed calculation. Finally, based on DSP on the the MPPT module and the subsequent stage inverter circuit module software programming, collected on the output voltage and current values of the battery plate and the inverter output current and voltage and the grid voltage signal sampling,signal input DSP in the main program, be programmed to perform MPPT function and inverter output current same frequency and phase with the grid voltage. Algorithms and hardware circuit is designed in this paper given at the end of photovoltaic grid-connected system simulation graphics and hardware output waveform to prove reasonable.