并网逆变器孤岛检测技术的研究

发布时间：2018-03-15 11:19

本文选题：并网逆变器　切入点：主动移频　出处：《燕山大学》2014年硕士论文　论文类型：学位论文

【摘要】：近年来，随着能源和环境问题日益加剧，新能源的开发和利用在当前备受关注。分布式发电系统给电力系统的结构和运行带来了很大的改变。孤岛效应和孤岛检测方法成为了电力系统安全稳定运行的关键。并网逆变器是分布式发电系统接入电网的核心部分。本文首先对并网逆变器的拓扑和控制方法做了概述，分别对单相、三相并网逆变器建模和闭环控制系统进行设计，并仿真验证了并网效果。其次分析了单相孤岛检测方法中的主动移频法、带正反馈的主动移频法以及周期性正反馈的主动移频法的原理，对于三相移频法，是通过无功电流的扰动，，来实现对PCC频率的偏移，并对以上各方法做了仿真分析。然后分析了电压正反馈法的不足，提出了单相自适应电压正反馈法，通过反馈系数的自适应变换，提高了检测速度，还提出了基于dq变换的电压标幺值正反馈的方法。同时，针对电网电压幅值不平衡情况，对负序电压正反馈法做了分析，并引入变系数，通过跟随电流给定值变化而不断变换反馈系数，使其能快速检测孤岛。最后，本文采用三相半桥逆变器作为主电路以及TMS320F2812作为控制电路主芯片，设计了整个系统硬件。使用C语言编程进行样机调试，完成了三相独立模式逆变器的双闭环，软件锁相环，三相并网逆变器的电流控制以及孤岛检测的过/欠压保护、电压标幺值正反馈法和负序电压正反馈法的实验。
[Abstract]:In recent years, with the energy and environmental problems become more and more serious, the development and utilization of new energy has attracted much attention in the current. The distributed power generation system has brought great changes to the structure and operation of the power system. Islanding and islanding detection method has become the key to the safe and stable operation of power system.
Grid connected inverter is the core part of the distributed generation system to connect to the power grid. Firstly, the topology and control method of grid connected inverter are summarized. The modeling and closed loop control system of single-phase and three phase grid connected inverter is designed, and the effect of grid connected is verified by simulation.
Secondly, the active frequency shift method of single-phase islanding detection method, active displacement principle of active frequency drift method frequency method and periodic positive feedback with positive feedback, the three-phase frequency shift method, by disturbing the reactive current, to achieve frequency offset on PCC, and the above parties do simulation and analysis.
Then analyzed the voltage positive feedback method, proposed adaptive single-phase voltage positive feedback method, the adaptive transform feedback coefficient, improve detection speed, also proposed the method of voltage dq transform p.u.inductance based on positive feedback. At the same time, according to the power grid voltage unbalance, negative sequence voltage positive feedback method do the analysis, and the introduction of variable coefficients, by following the current setting value changes and continue to transform the feedback coefficients so that it can quickly detect the island.
Finally, this paper adopts three-phase half bridge inverter as the main circuit and the TMS320F2812 chip as the main control circuit, the hardware design of the whole system. The use of C language programming debugging the prototype, completed a double loop three-phase independent mode inverter, software phase-locked loop, current control and islanding detection for three-phase grid connected inverter over / under voltage protection, positive experiment feedback and negative sequence voltage positive feedback method voltage per unit value.

【学位授予单位】：燕山大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM464

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