光伏并网逆变器直流分量抑制的研究

发布时间：2018-03-18 18:07

本文选题：隔离型并网逆变器　切入点：非隔离型并网逆变器　出处：《华北电力大学》2015年硕士论文　论文类型：学位论文

【摘要】：光伏发电迅速发展,光伏并网逆变器作为光伏系统主要设备,应给予极大的重视。由于各种原因,逆变器输出的交流电中会含有直流分量,,这些直流分量不仅对设备本身有危害,还会严重影响电网的电能质量,所以一定要对其加以抑制和补偿。本文首先对现在光伏系统广泛应用的几种光伏逆变器拓扑结构做了比较分析。研究发现,隔离型光伏并网逆变器输出的交流中基本不含直流分量；但是非隔离型并网逆变器由于缺少了隔离变压器的隔离作用,逆变器就会向电网中传送直流分量。第二,总结国内外对光伏并网逆变器输出直流分量的技术要求,分析非隔离型并网逆变器直流分量的产生机理以及直流分量对电网设备的危害。并从其产生原因入手,分析软件直流分量抑制方法和硬件直流分量抑制方法。第三,比较分析了现有的抑制直流分量的抑制方法。主要是从逆变器拓扑结构的改进,电容隔直法和直流分量检测电路的改进等几个方面着手消除直流分量。第四,在现有直流分量抑制方法的基础上提出直流分量综合抑制法,采用虚拟电容法和平均电流法相结合,在控制环中做两级反馈,最终实现对直流分量的抑制。并设计仿真算例仿真验证控制算法的可行性。
[Abstract]:Photovoltaic power generation is developing rapidly. As the main equipment of photovoltaic system, photovoltaic grid-connected inverter should be attached great importance to. DC components will be included in the AC power output of the inverter. These DC components will not only harm the equipment itself, but also seriously affect the power quality of the power grid. Therefore, it must be suppressed and compensated. Firstly, several kinds of photovoltaic inverter topology which are widely used in photovoltaic system are compared and analyzed in this paper. The AC output of isolated photovoltaic grid-connected inverter basically does not contain DC component, but the non-isolated grid-connected inverter will transmit DC component to the power network due to the lack of isolation function of isolation transformer. This paper summarizes the technical requirements of output DC component of photovoltaic grid-connected inverter at home and abroad, analyzes the generation mechanism of DC component of non-isolated grid-connected inverter and the harm of DC component to power grid equipment. The software DC component suppression method and the hardware DC component suppression method are analyzed. Thirdly, the existing DC component suppression methods are compared and analyzed. On the basis of the existing DC component suppression methods, a comprehensive DC component suppression method is proposed, which is based on the current DC component suppression method, and the improvement of the capacitance barrier method and the DC component detection circuit, etc., is taken to eliminate the DC component. The virtual capacitance method and the average current method are used to make two-stage feedback in the control loop, and finally the DC component is suppressed. A simulation example is designed to verify the feasibility of the control algorithm.
【学位授予单位】：华北电力大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TM464;TM615

【参考文献】