直流微电网建模与控制策略研究

发布时间：2018-04-02 09:01

本文选题：直流微电网　切入点：建模　出处：《华北电力大学》2014年硕士论文

【摘要】：能源危机促进了可再生分布式发电的迅速发展。为了减小分布式电源直接并网对电能质量的影响，通常将各种分布式发电装置有机结合组成微电网，然后并入主电网。交流微电网是目前主流的微电网形式，但是直流负荷的增加和直流分布式电源规模化给交流微电网带来了许多问题。将直流负荷和分布式电源直接接入直流微电网的形式在成本投资、电能质量以及可控性等方面都有很大的优势，借助电力电子技术可以实现对直流微电网的灵活控制，，充分发挥直流微电网的优势。本文深入分析了直流微电网的构成和微电源接口电路的原理与控制方式，在Matlab/Simulink环境下构建了并网型直流微电网模型。针对光伏发电系统，提出了指数型变步长扰动观察法的MPPT控制策略和恒压控制策略，建立了光伏发电系统模型；在蓄电池DC/DC接口控制方面，提出了充放电控制策略，实现了蓄电池双向充放电控制；在此基础上接入了小功率直驱式风力发电机仿真模型，使研究的直流微电网更具实用性。针对光伏直流微电网提出了协调电压控制策略。直流微电网无需考虑频率和相位问题，以直流母线电压为衡量系统稳定的唯一指标，因此控制直流母线电压稳定显得尤为重要。按照稳压源的不同将直流微电网分为三种基本运行状态，依据直流母线电压与蓄电池荷电状态SOC%(State of Charge)对三种状态间的转换进行控制，实现了直流微电网电压稳定控制的同时也达到了能量管理的目的。然后将小功率风力发电机接入直流微电网，实现了风光储直流微电网的电压控制，考虑了风机在夜间与白天参与稳压控制时投入的优先级不同。最后做了仿真模拟，结果表明提出的协调电压控制策略能够保证直流微电网的稳定运行和各状态的无缝切换。
[Abstract]:The energy crisis has promoted the rapid development of renewable distributed generation. In order to reduce the influence of direct grid connection of distributed generation on power quality, a variety of distributed generation devices are usually combined to form microgrid. And then into the main grid. Ac microgrid is the mainstream microgrid form. However, the increase of DC load and the scale of DC distributed generation bring many problems to AC microgrid. The direct connection of DC load and distributed power source to DC microgrid is invested in the cost. Power quality and controllability have great advantages. With the help of power electronics technology, we can realize the flexible control of DC microgrid and give full play to the advantages of DC microgrid. In this paper, the composition of DC microgrid and the principle and control mode of micro-power interface circuit are deeply analyzed. The grid-connected DC micro-grid model is constructed under Matlab/Simulink environment. The MPPT control strategy and constant voltage control strategy of exponential variable step-size disturbance observation method are proposed, and the photovoltaic system model is established, and the charging and discharging control strategy is put forward in the aspect of battery DC/DC interface control, and the bidirectional charging and discharging control of battery is realized. On this basis, the simulation model of low-power direct-drive wind turbine is connected, which makes the DC microgrid more practical. A coordinated voltage control strategy is proposed for photovoltaic DC microgrid, which takes DC bus voltage as the only index to measure the stability of the system without considering the frequency and phase. Therefore, it is very important to control the voltage stability of DC bus. According to the different voltage sources, the DC microgrid is divided into three basic operating states, and the conversion between the three states is controlled according to the DC bus voltage and the charging state of the battery SOC%(State of charge. The voltage stability control of DC microgrid is realized and the purpose of energy management is achieved. Then the low-power wind turbine is connected to DC micro-grid to realize the voltage control of wind-storage DC micro-grid. Considering the different priority of blower input in the night and daytime, the simulation results show that the proposed coordinated voltage control strategy can ensure the stable operation of DC microgrid and seamless switching of different states.
【学位授予单位】：华北电力大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM61

【参考文献】