三相并网逆变器的孤岛检测研究

发布时间：2018-01-07 06:16

本文关键词：三相并网逆变器的孤岛检测研究　出处：《燕山大学》2016年硕士论文　论文类型：学位论文

【摘要】：分布式发电系统中,太阳能、风能等通过电力电子变换后并入电网,然而当电网由于某种原因发生故障而中断供电时,分布式发电系统脱离电网后仍继续向负载供电,这种现象就称为孤岛效应。当孤岛发生后,分布式发电装置和本地用电设备可能会因为频率和电压失控而损坏,同时也会危及到检修人员的生命安全。因此必须及时检测到孤岛发生,使逆变器停止工作尤为重要。首先,本文建立了三相逆变器的数学模型,在此基础上分析了孤岛检测的基本原理,介绍了几种最常见的孤岛检测方法,其中被动检测没有加入任何扰动,所以不会对电能质量造成任何影响,但其存在较大的检测盲区;主动检测法是在逆变器输出端加入扰动,其会减小或消除检测盲区,但加入的扰动会对电能质量造成一定的影响,通常被动检测和主动检测方法结合使用。其次,本文针对有功电流扰动的孤岛检测进行了研究,通过分析有功电流与公共耦合点(PCC)电压的关系,可知加入适当的有功电流扰动就会使PCC电压触发孤岛检测的过压/欠压(OVP/UVP)保护。恒值电流扰动在负载不匹配时存在检测盲区,而且有功电流的持续注入,会影响逆变器的寿命或效率;周期电流扰动虽不存在检测盲区,但其存在负载不匹配时加入扰动量过大的问题;针对前两种电流扰动存在的不足,本文进行了自适应有功电流扰动的分析,其能够根据负载的实际情况自适应地加入电流扰动,使PCC点电压恰好触发孤岛检测的过压/欠压保护。相对于周期扰动而言,其在扰动量和扰动时间方面都有所减小,而且不存在检测盲区。本文通过MATLAB/Simulink软件,对三种有功电流扰动的方案进行了仿真对比,仿真结果验证了理论分析的正确性。最后,搭建了以TMS320F2812 DSP为控制核心的三相并网逆变器系统平台,在此平台上对三种有功电流扰动的孤岛检测方法进行了验证。实验结果表明,相比基于恒值电流扰动和周期电流扰动的孤岛检测方法,自适应电流扰动法能根据PCC点电压自适应地加入扰动量的大小,扰动时间也有所减小,且不存在检测盲区。
[Abstract]:Distributed solar power system, wind power, etc. through power electronic conversion after the grid, however, when the power grid and power interruption due to failure of some reason, the distributed power generation system from the power grid continue to supply power to the load, this phenomenon is known as the island effect. When after the island, distributed generation and local electricity equipment because of the frequency and voltage control and damage, but also endanger the life safety of the maintenance staff. Therefore we must timely detect the islanding occurs, the inverter stop work is particularly important. Firstly, this paper established a mathematical model of three-phase inverter based on the analysis of the basic principle of islanding detection, introduces several methods of the islanding detection often, the passive detection without any disturbance, so it will not cause any impact on the power quality detection, but the existence of large blind zone The active detection method is added; perturbations in the output terminal of the inverter, which can reduce or eliminate the blind spot detection, but adding disturbance will cause a certain impact on power quality, usually passive detection and active detection method using the combination. Secondly, this paper studies the detection of active current disturbance Island, through the analysis of the active current and the public coupling (PCC) voltage, the addition of active current suitable perturbations will make PCC voltage trigger overvoltage / undervoltage islanding detection (OVP/UVP) protection. Constant current in the load disturbance detection zone does not match, and the active current continuous infusion, will affect the lifetime of the inverter or current disturbance cycle efficiency; although there is no blind spot detection, but the existence of load disturbance into the problem of large mismatch; aiming at the shortage of current disturbance before two, the adaptive active current The disturbance analysis, it can according to the actual situation of adding adaptive load current disturbance, the PCC voltage to trigger overvoltage / undervoltage protection of islanding detection. Compared with the periodic disturbance, the disturbance and the disturbance time is reduced, and there is no blind spot detection. Based on the MATLAB/Simulink software, the simulation three kinds of active current perturbation scheme, the simulation results verify the correctness of the theoretical analysis. Finally, built on the TMS320F2812 platform of DSP three-phase inverter control system, this platform is tested on the three kinds of active current disturbance islanding detection method. The experimental results show that compared with the current disturbance and islanding detection method cycle of constant current disturbance based on adaptive current perturbation method according to PCC voltage adaptively adding perturbation quantity size, when the disturbance is also It is reduced and there is no detection blind area.

【学位授予单位】：燕山大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TM464

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