直流微网母线电压控制与能量协调策略研究

发布时间：2018-03-24 10:21

  本文选题：直流微网　切入点：分布式发电　出处：《重庆理工大学》2015年硕士论文

【摘要】：随着能源需求的不断发展,分布式发电(Distributed Generation,DG)已成为必由之路。微网作为具有自发自用能力的可控系统,既可与主网互联运行,又可脱离主网孤岛运行。当DG输出突变、大量负荷同时投切、并网孤岛切换时,很可能引起母线电压波动,甚至使控制或保护系统误动作。因此,研究直流微网稳定运行的控制技术,维持母线电压的稳定性,同时实现能量最优协调控制,具有重要的理论意义及实际应用价值。基于此,文内以直流微网系统为研究对象,分析设计了有关单元变换器控制策略及基于电压分层控制的系统控制策略。首先,分析了直流微网的有关问题及其在未来城乡区域供配电系统中的趋势,对直流母线电压稳定控制及网内能量优化协调控制的现状进行了分析研究。构建了满足系统运行稳定性和可靠性要求的直流微网系统模型,为直流微网内单元变换器自主控制策略及系统控制策略的研究提供基础。第二,以光伏发电单元、并网接口变换器单元、蓄电池单元、燃料电池单元和负荷单元构成的直流微网系统为研究对象,研究建立各单元变换器工作状态自主切换控制策略,以便实现各变换器在不同工作状态间快速、平滑地自主切换。第三,建立了一种直流微网在并网运行状态下及孤岛运行网内功率平衡状态下的能量最优利用控制策略。所建立的控制策略能够在直流微网并网运行状态,以及孤岛运行网内供需平衡状态下,维持母线电压的稳定,同时实现可再生能源及蓄电池的最优利用。第四,为解决直流微网孤岛运行时,网内功率不平衡引起的母线电压波动问题,设计了一种储能充放电自主调节控制策略。当母线电压进入该策略预设电压区间时,利用蓄电池的功率缓冲能力,以蓄电池单元作为网内平衡节点,蓄电池单元变换器根据母线电压变化自主切换至下垂充电控制或下垂放电控制状态,使网内功率重新达到平衡,从而实现母线电压的稳定控制。最后,构建了一种考虑网内功率严重不平衡的直流微网极限运行控制策略。所构建的控制策略以保证直流微网在极限运行状态下的可靠性为目标,通过光伏单元输出自主控制及辅助电源的投入运行,有效抑制因网内功率严重不平衡引起的母线电压大范围波动,有效避免系统崩溃可能性。
[Abstract]:With the continuous development of energy demand, distributed generation DG has become the only way. As a controllable system with spontaneous self-use capability, microgrid can not only run interconnected with the main network, but also run off the island of the main network. When a large number of loads are switched on and off at the same time, it is likely to cause bus voltage fluctuation and even make the control or protection system misoperate. Therefore, the control technology for steady operation of DC microgrid is studied to maintain the stability of bus voltage. At the same time, the realization of optimal coordinated control of energy has important theoretical significance and practical application value. Based on this, the DC microgrid system is taken as the research object in this paper. The control strategy of cell converter and the system control strategy based on voltage stratification control are analyzed and designed. Firstly, the problems related to DC microgrid and its trend in the future power supply and distribution system in urban and rural areas are analyzed. The current situation of DC bus voltage stability control and energy optimization and coordination control in the grid is analyzed and studied. A DC microgrid system model which meets the requirements of system operation stability and reliability is constructed. It provides the foundation for the research of the self-control strategy and system control strategy of DC micro-grid converter. Second, the photovoltaic unit, grid-connected converter unit, battery unit, The DC microgrid system composed of fuel cell unit and load unit is studied. The independent switching control strategy of each unit converter is established in order to realize the fast switching between different working states of the converter. Thirdly, a control strategy for optimal energy utilization of DC microgrid in grid-connected operation and power balance state in islanding operation network is established. The proposed control strategy can operate in DC microgrid grid-connected state. Under the condition of equilibrium of supply and demand, the bus voltage can be kept stable, and the renewable energy and battery can be utilized optimally. Fourth, in order to solve the problem of DC microgrid isolated island operation, Based on the problem of bus voltage fluctuation caused by power imbalance in the network, a self-regulating control strategy for energy storage charge and discharge is designed. When the bus voltage enters the preset voltage range of the strategy, the power buffering capacity of the battery is utilized. With the battery unit as the balance node in the network, the battery cell converter switches to the droop charging control or the droop discharge control state according to the voltage variation of the bus, so that the power in the network can be rebalanced. So as to realize the stable control of bus voltage. Finally, In this paper, a DC microgrid limit operation control strategy considering the serious power imbalance in the grid is proposed. The goal of the control strategy is to ensure the reliability of the DC microgrid under the limit operation condition. Through the output autonomous control of photovoltaic unit and the operation of auxiliary power supply, the fluctuation of bus voltage caused by the serious imbalance of power in the grid is effectively restrained, and the possibility of system collapse is effectively avoided.
【学位授予单位】：重庆理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TM61;TM712

【参考文献】

中国期刊全文数据库 前8条

1 李鹏;张玲;王伟;杨希磊;赵义术;;微网技术应用与分析[J];电力系统自动化;2009年20期

2 赵宏伟;吴涛涛;;基于分布式电源的微网技术[J];电力系统及其自动化学报;2008年01期

3 丁明;张颖媛;茆美琴;;微网研究中的关键技术[J];电网技术;2009年11期

4 张文亮;汤涌;曾南超;;多端高压直流输电技术及应用前景[J];电网技术;2010年09期

5 米为民;荆铭;尚学伟;徐丹丹;蒋国栋;付辉;;智能调度分布式一体化建模方案[J];电网技术;2010年10期

6 傅书，

本文编号：1657873