新型分布式发电光伏并网逆变器研究

发布时间：2018-06-25 18:37

本文选题：并网逆变器 + 小信号模型　；参考：《华东交通大学》2017年硕士论文

【摘要】：在全球范围内随着能源的不断消耗以及污染的不断加剧,使用新能源进行并网发电的技术越来越成为了科技工作者的研究重点。光伏并网逆变器是将分布式光伏发电系统与电网进行连接的重要装置,是分布式光伏并网发电系统的核心,对整个发电系统的稳定运行起到关键的作用。所以,对光伏并网逆变器进行研究具有重要的意义。本文简要介绍了并网逆变器的各种电路拓扑结构,并详细研究了用于小型分布式发电系统的低成本逆变器电路拓扑结构,即三开关单级升降压并网逆变器,该逆变器使用的开关管数量少,拓扑结构简单、输出效率高且升降压范围广的优点。分析了逆变器工作在电感电流断续模式下,对闭环SPWM方法的PID控制器参数进行优化。本文设计一种综合指标J,该指标能同时反映系统的鲁棒性和系统的偏差积分性能,采用全空间循环搜索的方法,寻找最优的J值,最终得到PID控制器优化后的参数。仿真及实验研究表明对PID参数优化后,在输入电压发生较大变化时,该逆变器的输出电流能够维持稳定,且与电网电压同步,THD较低。在本论文中,分析了一种基于能量控制的逆变器调制方法:脉冲能量调制(PEM)。使用Lyapunov稳定性判据来分析PEM逆变器的稳定性。这种调制技术是以能量控制为基础的,通过计算每个开关周期的能量需求大小来计算脉冲宽度,从而实现逆变器控制。能量需求由输出电压和参考电流计算,逆变器的调制度是基于瞬时能量需求进行计算的。并且还建立PEM逆变器的小信号等效模型,与PWM逆变器相比,PEM升降压逆变器的性能得到了较大的提升。仿真结果表明,PEM方法能够提供更稳定的正弦输出量,具有较低的THD值,并且能够适用于更宽的直流输入电压及更宽的输出功率范围。
[Abstract]:With the continuous consumption of energy and the worsening of pollution, the technology of grid-connected power generation using new energy has become the research focus of science and technology workers. Grid-connected photovoltaic inverter is an important device to connect the distributed photovoltaic system to the grid. It is the core of the distributed photovoltaic grid-connected generation system and plays a key role in the stable operation of the whole generation system. Therefore, it is of great significance to study photovoltaic grid-connected inverter. This paper briefly introduces various circuit topologies of grid-connected inverters, and studies in detail the circuit topology of low-cost inverters for small distributed generation systems, that is, three-switch single-stage lifting voltage grid-connected inverters. The inverter uses a small number of switches, simple topology, high output efficiency and a wide range of lifting voltage. The pid controller parameters of the closed loop SPWM method are optimized under the intermittent inductance current mode. In this paper, a comprehensive index J is designed, which can reflect both the robustness of the system and the deviation integral performance of the system. The optimal J value is found by the method of full space cyclic search, and the optimized parameters of the pid controller are obtained. The simulation and experimental results show that the output current of the inverter is stable and the THD is low when the input voltage changes greatly after the pid parameters are optimized. In this paper, an energy control based inverter modulation method, pulse energy modulation (PEM), is analyzed. Lyapunov stability criterion is used to analyze the stability of PEM inverter. This modulation technique is based on energy control. The pulse width is calculated by calculating the energy requirement of each switching cycle, and the inverter control is realized. The energy requirement is calculated by the output voltage and reference current, and the modulation of the inverter is based on the instantaneous energy requirement. The small signal equivalent model of PEM inverter is also established. Compared with PWM inverter, the performance of PEM inverter is greatly improved. The simulation results show that the PEM method can provide a more stable sinusoidal output, have a lower THD value, and can be applied to a wider DC input voltage and a wider output power range.
【学位授予单位】：华东交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM464;TM615

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