新型主从控制的微电网模式切换策略研究

发布时间：2018-04-09 23:38

本文选题：微电网　切入点：模式切换　出处：《哈尔滨工业大学》2014年硕士论文

【摘要】：微电网的模式切换技术是微电网控制技术的关键组成部分。本文在分析模式切换技术在国内外研究现状的基础上，针对主从控制策略切换难度大、参数跟踪复杂和下垂控制策略动态特性差、运行点偏离的问题，提出了一种可实现微电网模式平滑切换的新型主从控制策略。这种策略可解决传统主从控制在模式改变过程中功率自动分配困难、参数跟踪复杂和控制器需要切换的三个突出问题。它采用多环反馈控制结构，从外到内依次为电压频率环、内置参数环、电压环和电流环。电压频率环具有下垂特性能实现功率的自动配置；内置参数环在模式切换时能实现参数的自动跟踪，不用再外接控制器；电压环能跟踪稳态电压；电流环能提高系统响应速度。这种控制策略既适用于并网模式又适用于离网模式，模式切换时将不再需要切换控制器拓扑。为证实新型主从控制策略的可行性，本文设计了一个采用这种控制策略的微电网系统，，并对其进行了稳定性分析。稳定性分析包括稳态稳定性分析和暂态稳定性分析，又可称为小信号稳定性分析和暂稳态稳定性分析。其中的暂稳态稳定性主要指模式切换下的暂稳态稳定性。小信号稳定性在系统整体数学模型基础上，建立了状态空间方程，发现其状态矩阵的特征值均具有负实部，证实了采用这种控制策略的微电网系统是具有小信号稳定性的，能在小扰动下保持稳定。暂稳态稳定性分析在系统仿真模型的基础上，进行了Matlab仿真，发现采用这种控制策略的微电网系统在正常工况下，模式切换的暂态消除时间均小于最大故障清除时间，证明了它是模式切换暂稳态稳定的，能抵抗模式切换这样的大扰动。最后，和采用传统主从控制策略、多环下垂控制策略的微电网系统进行了模式切换效果的对比，再次证实了新型主从控制策略在模式切换时的优越性。
[Abstract]:The mode switching technology of microgrid is a key component of microgrid control technology.Based on the analysis of the current research situation of mode switching technology at home and abroad, this paper aims at the difficulties of master-slave control strategy switching, the complexity of parameter tracking, the poor dynamic characteristics of droop control strategy, and the deviation of running point.A new master-slave control strategy which can realize smooth switching of microgrid mode is proposed.This strategy can solve the three outstanding problems of the traditional master-slave control, such as the difficulty of automatic power allocation, the complexity of parameter tracking and the switching of the controller.It adopts multi-loop feedback control structure. From outside to inside, it is a voltage frequency loop, a built-in parameter loop, a voltage loop and a current loop.The voltage frequency loop has sag characteristic to realize the automatic configuration of power; the built-in parameter loop can realize the automatic tracking of the parameters when the mode is switched without the external controller; the voltage loop can track the steady voltage; the current loop can improve the system response speed.This control strategy is suitable for both grid-connected and off-grid modes, and the switching controller topology will no longer be required for mode switching.In order to prove the feasibility of the new master-slave control strategy, a microgrid system using this control strategy is designed and its stability is analyzed.Stability analysis includes steady stability analysis and transient stability analysis, which can be called small signal stability analysis and transient stability analysis.The transient stability mainly refers to the transient stability under mode switching.On the basis of the whole mathematical model of the system, the state space equation is established, and the eigenvalues of the state matrix are found to have negative real parts. It is proved that the microgrid system using this control strategy has small signal stability.Can maintain stability under small disturbance.On the basis of system simulation model, the transient stability analysis of microgrid system with this control strategy is carried out by Matlab simulation. It is found that the transient elimination time of mode switching is less than the maximum fault removal time under normal working conditions.It is proved that it is stable in the transient state of mode switching and can resist the large disturbance of mode switching.Finally, compared with the traditional master-slave control strategy and multi-loop droop control strategy, the effect of mode switching is compared, and the superiority of the new master-slave control strategy in mode switching is proved again.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM73

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