三相光伏逆变器的研制

发布时间：2018-03-26 12:20

本文选题：光伏发电　切入点：逆变器　出处：《湖南大学》2014年硕士论文

【摘要】：随着社会经济的高速发展，人类对电力的需求日益增大，而能源紧缺与环境污染问题日益加重，促进了人类对可再生能源发电技术的研究。太阳能取之不尽，用之不竭，绿色环保，发展前景巨大，因此光伏发电成为近年来研究的热点。本文以三相光伏逆变器为研究对象，从工程实现的角度出发，深入研究了三相光伏并网逆变器的拓扑结构、主电路工作原理和参数设计、并网控制方法和基于DSP控制系统的硬件软件设计，并在此基础上研制开发了一套三相光伏并网逆变器样机。本文首先分析了光伏并网逆变器系统的主电路结构。在对比分析了几种常用的三相光伏逆变器主电路原理及特性的基础上，确定了三相光伏并网逆变器系统的主电路采用单级式非隔离型的拓扑结构。并详细分析讨论了直流侧电容、逆变器输出滤波电感等主电路元器件参数的设计方法。在确定了系统主电路方案后，本文提出了一种直流侧电压外环、逆变器输出电流内环的双闭环控制策略。通过对逆变器输出电流内环建立内环电气模型，并运用理论分析与仿真验证，对比分析了电流内环分别采用PI控制和无差拍控制时逆变器输出性能的差异，最终本文逆变器输出电流内环确定采用无差拍控制的方法。然后对比分析了目前常用的几种最大功率跟踪算法，综合考虑各种算法的优缺点，从装置实现的角度出发，提出了一种改进的变步长扰动观测法作为本文的最大功率跟踪算法。最后，通过对比分析确定了一种被动电压/频率检测法的孤岛检测方案，并给出了详细的软件实现流程。控制器系统硬件软件设计与实现是本文研究的重点之一。文中首先就主要硬件电路，包括外围采样电路、过零捕获电路、保护电路、串口通信电路等设计方法作了详细介绍，，并给出了主要检测元件参数的设计方法。然后设计了主程序、中断程序、串口通信程序等软件的详细流程。最后本文用PSIM软件搭建了三相光伏逆变器的仿真模型，对其性能进行了仿真验证。根据前文的设计，在实验室研制了一台三相光伏并网逆变器样机，并对其并网性能进行了实验测试，验证了本文所设计电路结构及控制算法的合理性。本文研究设计内容可以为各功率等级光伏逆变并网技术提供借鉴与参考。
[Abstract]:With the rapid development of social economy, the demand for electricity is increasing, and the problems of energy shortage and environmental pollution are becoming more and more serious, which has promoted the research of renewable energy generation technology. Solar energy is inexhaustible and inexhaustible. The green environment protection, the development prospect is huge, therefore the photovoltaic generation becomes the research hot spot in recent years. This paper takes the three-phase photovoltaic inverter as the research object, from the engineering realization angle, has deeply studied the three-phase photovoltaic grid-connected inverter topology structure, The main circuit working principle and parameter design, grid-connected control method and hardware and software design based on DSP control system are designed, and a prototype of three-phase photovoltaic grid-connected inverter is developed. In this paper, the main circuit structure of photovoltaic grid-connected inverter system is analyzed, and the principle and characteristics of several common three-phase photovoltaic inverters are compared and analyzed. The main circuit of the three-phase photovoltaic grid-connected inverter system is defined as a single-stage non-isolated topology, and the design method of the main circuit components parameters such as DC side capacitance and inverter output filter inductance is discussed in detail. After determining the scheme of the main circuit of the system, this paper presents a double closed loop control strategy for the DC side voltage outer loop and the inverter output current inner loop, and establishes the internal loop electrical model for the inverter output current inner loop. By using theoretical analysis and simulation, the difference of output performance of inverter with Pi control and non-beat control in current inner loop is compared and analyzed. Finally, the output current inner loop of the inverter is determined by using the deadbeat control method. Then, several commonly used maximum power tracking algorithms are compared and analyzed, considering the advantages and disadvantages of the various algorithms, and from the point of view of the device implementation, An improved variable step size perturbation observation method is proposed as the maximum power tracking algorithm in this paper. Finally, a novel islanding detection scheme of passive voltage / frequency detection method is determined through comparative analysis, and a detailed software implementation flow is given. The design and implementation of hardware and software of controller system is one of the emphases of this paper. Firstly, the design methods of main hardware circuits, including peripheral sampling circuit, zero-crossing acquisition circuit, protection circuit, serial communication circuit and so on, are introduced in detail. Then the main program, interrupt program and serial communication program are designed. Finally, the simulation model of three-phase photovoltaic inverter is built with PSIM software, and its performance is verified by simulation. According to the design above, a prototype of three-phase photovoltaic grid-connected inverter is developed in the laboratory. The experimental results show that the circuit structure and the control algorithm are reasonable. The research and design of this paper can provide reference for grid-connected technology of photovoltaic inverter with different power levels.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM464

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