發(fā)布時間：2018-11-01 11:32

【摘要】：隨著電網(wǎng)規(guī)模的擴大,傳統(tǒng)大電網(wǎng)集中供電難以適應用戶多元化的供電需求,促使了分布式發(fā)電技術(shù)的發(fā)展。但由于分布式電源的隨機性和不可控性,又限制了分布式電源的利用和使用效率。作為分布式電源的有效利用形式,微網(wǎng)既能充分利用分布式電源的優(yōu)勢,又能協(xié)調(diào)分布式發(fā)電和大電網(wǎng)之間的矛盾。微網(wǎng)的控制策略決定其在孤島和并網(wǎng)模式下的運行情況,并影響運行模式切換的平滑性。因此,確定合適的控制策略是實現(xiàn)微網(wǎng)穩(wěn)定運行的關(guān)鍵。 首先,本文分析了下垂控制基本原理和微網(wǎng)的下垂控制特性,給出了三相電壓型逆變器的數(shù)學模型及其LC濾波器參數(shù)的設計準則,依據(jù)逆變器的數(shù)學模型和設計準則分析了包含功率測量模塊、下垂特性控制模塊和電壓電流雙閉環(huán)控制模塊的逆變器下垂控制器,并給出了下垂控制器在低壓微網(wǎng)中的應用。其次,本文在微網(wǎng)對等控制體系下的運行模式基礎(chǔ)上,給出了低壓微網(wǎng)運行控制策略。在孤島運行模式下,針對連接阻抗差異造成的功率分配不準確以及負荷變化引起的電壓不穩(wěn)定問題,給出了改善無功分配精度、提高電壓穩(wěn)定性的自調(diào)節(jié)改進下垂控制器設計；在模式切換狀態(tài)下,給出了同步并網(wǎng)下垂控制器設計,通過調(diào)節(jié)微電網(wǎng)輸出的電壓使得微電網(wǎng)與大電網(wǎng)的電壓幅值差、頻率差和相角差滿足并網(wǎng)要求,以實現(xiàn)微網(wǎng)在孤島和并網(wǎng)兩種模式之間的平滑切換。 最后,在Matlab/Simulink環(huán)境下搭建了低壓微網(wǎng)運行控制仿真系統(tǒng),分別對微網(wǎng)孤島模式運行、模式切換運行狀態(tài)進行了仿真實驗,仿真結(jié)果分析表明所提出的低壓微網(wǎng)運行控制策略和所設計的自調(diào)節(jié)改進下垂控制器及同步并網(wǎng)下垂控制器的有效性。
[Abstract]:With the expansion of power grid scale, traditional centralized power supply in large power grid is difficult to adapt to the diversified power supply demand of users, which promotes the development of distributed generation technology. However, due to the randomness and uncontrollability of distributed power, the utilization and efficiency of distributed power are limited. As a form of efficient utilization of distributed generation, microgrid can not only make full use of the advantages of distributed generation, but also can coordinate the contradiction between distributed generation and large power grid. The control strategy of microgrid determines its operation in isolated island and grid-connected mode, and affects the smoothness of switching operation mode. Therefore, to determine the appropriate control strategy is the key to realize the stable operation of the microgrid. Firstly, the basic principle of droop control and the droop control characteristics of microgrid are analyzed, and the mathematical model of three-phase voltage source inverter and the design criteria of LC filter parameters are given. According to the mathematical model and design criterion of inverter, the droop controller of inverter including power measurement module, droop characteristic control module and voltage and current double closed loop control module is analyzed, and the application of droop controller in low voltage microgrid is given. Secondly, based on the operation mode of micro-grid peer-to-peer control system, a low-voltage microgrid operation control strategy is presented. In the isolated operation mode, aiming at the inaccurate power distribution caused by the difference of the connection impedance and the voltage instability caused by the load variation, a self-regulating improved sagging controller is designed to improve the reactive power distribution accuracy and increase the voltage stability. In the mode switching state, the design of synchronous grid-connected droop controller is presented. By adjusting the output voltage of microgrid, the voltage amplitude difference, frequency difference and phase angle difference between microgrid and large power grid can meet the requirements of grid-connected. In order to realize the smooth switching between island and grid-connected modes. Finally, the simulation system of low-voltage microgrid operation control is built in Matlab/Simulink environment, and the simulation experiments are carried out for the operation of isolated island mode and mode switching state of microgrid. The simulation results show the effectiveness of the proposed low-voltage microgrid operation control strategy and the self-tuning improved droop controller and synchronous grid-connected droop controller.
【學位授予單位】：西南交通大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TM732

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相關(guān)期刊論文 前10條

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本文編號：2303795