微电网中多逆变器并联控制的研究

发布时间：2018-06-18 23:14

本文选题：微电网逆变器 + 准PR控制器　；参考：《东北大学》2014年硕士论文

【摘要】：目前为止,化石能源的日益匮乏与环境污染现象形势较为严峻,微电网技术以其独有的优点受到国内外学者的广泛关注。微电网中的分布式发电单元以逆变器作为功率变换接口为负载提供电能,逆变控制技术是微电网中最为关键的技术之一。微电网逆变器大多以并联的形式提高系统的容量及可靠性。微电网逆变器在并联运行时存在着诸多需要解决的问题,本文主要研究低压微电网中多逆变器并联运行在输电线路较长时的电压补偿及环流抑制的问题。首先,本文介绍了微电网提出的背景及研究意义,并阐述微电网逆变器的主要功能,对微电网逆变器进行数学建模并分析了其常用的输出波形调制方法,设计电力滤波器保证输出电压质量。详细分析了目前微电网逆变器的控制方法,通过比较分析,选择准PR控制器作为电压外环,比例控制器作为电流内环来保证系统的性能。在此基础上,介绍了并联微电网逆变器间主要存在的问题及常用的解决方法。其次,在低压微电网中,输电线路以阻性为主,造成了传统下垂控制方法的局限性,传统的虚拟阻抗控制方法可以优化线路的阻感比,然而,在输电线路较长时,需要较大的虚拟阻抗才能保证传统下垂控制方法在微电网中的应用。针对传统虚拟阻抗的缺点,本文采用了一种改进的虚拟阻抗控制方法,虚拟阻抗的配置不再依赖于线路参数,能够很好的保证逆变器输出电压质量。微电网并联逆变器应用下垂控制保证逆变器输出功率均分的同时会造成逆变器输出电压频率及幅值的偏移,而负载一般对频率较为敏感,对此,本文采用一种分散式调频控制方法,保证逆变器输出频率为额定值,并且通过MATLAB仿真验证改进虚拟阻抗方法的正确性。最后,结合本文对单相逆变系统进行了软硬件设计。以TMS320F2812DSP为核心搭建实验平台,设计软件流程并在CCS编译软件中用C语言编写软件程序,得到相关实验数据和波形。
[Abstract]:Up to now, the situation of fossil energy shortage and environmental pollution is more severe. Microgrid technology has been widely concerned by scholars at home and abroad for its unique advantages. The inverter is used as the power conversion interface to provide power for the load in the distributed generation unit in the microgrid. The inverter control technology is one of the most important technologies in the micro-grid. Most microgrid inverters improve the capacity and reliability of the system in parallel. There are many problems that need to be solved in parallel operation of microgrid inverters. This paper mainly studies the voltage compensation and loop suppression of multi-inverter parallel operation in low-voltage microgrid when the transmission line is longer. Firstly, the background and research significance of microgrid inverter are introduced, and the main functions of microgrid inverter are described. The mathematical model of microgrid inverter and its common output waveform modulation method are analyzed. Power filter is designed to guarantee the quality of output voltage. The control methods of microgrid inverter are analyzed in detail. By comparison and analysis, the quasi-PR controller is chosen as the voltage outer loop and the proportional controller as the current inner loop to ensure the performance of the system. On this basis, the main problems and common solutions between parallel microgrid inverters are introduced. Secondly, in the low-voltage microgrid, the transmission line is mainly resistive, which results in the limitation of the traditional droop control method. The traditional virtual impedance control method can optimize the resistance / sense ratio of the transmission line, however, when the transmission line is longer, the resistance / sense ratio of the transmission line can be optimized by the traditional virtual impedance control method. Large virtual impedance is needed to ensure the application of traditional droop control method in microgrid. Aiming at the shortcoming of traditional virtual impedance, an improved virtual impedance control method is adopted in this paper. The configuration of virtual impedance is no longer dependent on line parameters, which can guarantee the output voltage quality of inverter. The application of droop control in microgrid parallel inverter ensures that the output power of the inverter is equally divided and the output voltage frequency and amplitude of the inverter are offset, but the load is generally sensitive to the frequency. In this paper, a decentralized frequency modulation control method is used to ensure that the output frequency of the inverter is rated, and the correctness of the improved virtual impedance method is verified by MATLAB simulation. Finally, the hardware and software of the single-phase inverter system are designed. The experimental platform is built with TMS320F2812 DSP as the core, the software flow is designed and the software program is written in C language in the CCS compiling software, and the related experimental data and waveform are obtained.
【学位授予单位】：东北大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM464

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