微网孤网运行控制策略研究

发布时间：2018-04-05 02:00

本文选题：微网　切入点：分布式电源　出处：《西南交通大学》2014年硕士论文

【摘要】：随着近年来环境问题越来越突出以及能源危机日益加深的影响,以可再生能源为主的分布式发电技术得到了很快的发展。作为电力系统的一种新的网络结构,微网能够较好的解决分布式发电与大电网并网的问题,为解决可再生能源的低利用率提供了解决方案,对于落实我国节能减排的任务具有重要的意义。微网技术的研究是当前的热点,其中最基本的问题是微网的控制策略问题,而作为大电网的补充,微网在孤岛时的运行为用户带来了可靠供电和用电安全保障,因此,如何解决微网孤网的控制问题对微网的发展至关重要。本文对基于光伏和蓄电池模型结构的微网控制进行了仿真和分析。首先建立了典型带蓄电池的光伏(PV)电池模型,包括三相逆变器,光伏电池,Boost变换器,蓄电池储能单元,蓄电池充放电Buck/Boost变换器,并对其相应控制电路模型进行了一定分析。然后根据所建立的光伏和蓄电池模型及相应变换器的数学模型,建立了光伏电池的仿真模型,并对其最大功率跟踪进行了仿真分析。对其充放电模型进行了仿真和分析。基于P/V的倒下垂控制具有显著的优点,其负载跟随功率特性很好。但当负载功率波动频繁时,会出现光伏储能系统的功率频繁变动,会引起蓄电池的频繁充放电,降低了电池的使用寿命。为了解决上述问题,本文采用一种基于Vg/Vdc的控制方法来改进P/V控制策略,这种控制策略下,负荷功率在一定范围波动时,通过调整输出电压幅值来使系统功率达到平衡而不需要对蓄电池进行充放电。最后,在Matlab/simulink环境下搭建了光伏带储能的微网孤网仿真模型。对Vg/Vdc控制、基于Vg/Vdc的改进P/V下垂控制进行了仿真验证,仿真结果表明Vg/Vdc能够较好较快的调节系统功率使之平衡,同时在负载或分布式电源单元功率小范围波动时,可不对储能单元进行充放电,这样增加了储能单元的使用寿命；基于Vg/Vdc的改进P/V下垂控制弥补了P/V下垂控制调节下储能系统有时频繁充放电缺点,同时,该方法还能较好的实现负载的功率均分。该微网仿真模型为进一步的研究提供了基础,对微网控制方案的验证及微网技术的发展具有一定的实际应用价值。
[Abstract]:With the influence of environmental problems more and more prominent in recent years, the energy crisis deepens increasingly, distributed generation technologies based on renewable energy has been developed rapidly. As a new network structure of the power system, the microgrid can solve the problem of distributed generation and grid better problem, provides a solution for low utilization to solve the renewable energy rate, has important significance for our country to implement energy-saving emission reduction task. Research on Microgrid technology is a hot topic at present, one of the most basic problem is the problem of control strategy of microgrid, for large power grid, microgrid in island operation for users and reliable power supply electricity security, therefore, how to solve the control problem of isolated microgrid on micro grid development is very important.
The photovoltaic and battery model structure of microgrid control is simulated and analyzed. Based on the established first with typical photovoltaic battery (PV) battery model, including three-phase inverter, photovoltaic cell, Boost converter, battery storage unit, battery charge and discharge Buck/ Boost converter, and the corresponding control circuit model some analysis. Then according to the mathematical model of PV and battery model and corresponding converter, established the simulation model of photovoltaic cells, and the maximum power tracking is analyzed. The charge discharge model is simulated and analyzed.
P/V droop control has significant advantages based on the load following power characteristics very well. But when the load power fluctuates frequently, will power photovoltaic energy storage system with frequent changes, frequent charge discharge will cause the battery, reduce the service life of the battery. In order to solve the above problems, this paper adopts a control method Vg/Vdc based on improved P/V control strategy, the control strategy, load power changes within a certain range, by adjusting the power output voltage amplitude enables the system to achieve balance without the need to charge and discharge the battery.
Finally, in the Matlab/simulink environment to build a photovoltaic energy storage microgrid with isolated network simulation model. The Vg/Vdc control, improved P/V Vg/Vdc droop control simulation based verification, simulation results show that Vg/Vdc can better regulate the balance of power in the system, at the same time load or distributed power unit power fluctuation. Without a storage unit to charge and discharge, so as to increase the service life of the storage unit; based on improved P/V Vg/Vdc control for P/V droop droop control under the regulation of the energy storage system sometimes frequent charging and discharging shortcomings, at the same time, the implementation of the power load sharing method is also good.
The micro network simulation model provides a basis for further research, and has a certain practical application value for the verification of micro network control scheme and the development of micronetwork technology.

【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM732

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