微电网混合储能分层模糊控制策略研究

发布时间：2018-11-14 12:11

【摘要】：现代电力能源中,基于风力发电和太阳辐射发电的清洁能源具有出力随机、间歇性停运和功率波动较为频繁的特点。本文主要针对10kV以下交流微电网,以平抑分布式能源功率波动,减小分布式能源对微电网并网运行和孤岛运行的不利影响为目的,研究了基于微电网混合储能系统的充放电控制策略。首先,本文对分布式电源功率波动特点进行了分析,将系统出力分为稳态波动功率、峰值波动功率以及往复性波动功率三种功率波动类型,并根据系统功率波动的平抑要求,研究发现超级电容器和铅酸蓄电池二者存在优势互补,所组成的混合储能系统可以有效吞吐波动功率,提高微电网的电能质量。然后,将不同储能元件复合结构进行对比分析,确定使用含有双向DC/DC变换器的两级并联结构作为集中式微电网的混合储能系统的复合结构。接着设计了一种由实时状态层、逻辑运算层与系统控制层组成的三层控制模型。其中,实时状态层主要用于采集微电网系统的功率波动信号与超级电容器的荷电状态,并制定基于超级电容器首先进行功率吞吐原则的充放电规则。逻辑运算层提供控制对象库和控制算法库两种检索预置库。通过检索控制对象库可得到超级电容器与蓄电池不同充放电状态下的控制对象,然后将控制对象传递给系统控制层,系统控制层对控制算法库进行检索,即可以得到相适应的控制算法,然后经过脉宽调制双向DC/DC变换器占空比可对混合储能系统功率吞吐进行协调控制。同时在系统控制层引入自整定模糊PI控制器替代传统PI控制器作为辅助,可起到平抑功率非线性波动,优化系统运行的作用。最后,本文使用在Matlab/Smiulink仿真平台搭建风光储微电网的模型进行计算仿真,证实提出的分层模糊控制策略能够有效稳定储能系统直流电压,平抑分布式电源功率波动,保证微电网并网和孤岛模式的稳定运行,实现负荷投切的平滑过渡。
[Abstract]:Among modern power sources, clean energy based on wind power generation and solar radiation power generation has the characteristics of random output, intermittent outage and frequent power fluctuation. The purpose of this paper is to suppress the fluctuation of distributed energy power and reduce the adverse effect of distributed energy on microgrid operation and islanding operation. Charge and discharge control strategy based on microgrid hybrid energy storage system is studied. Firstly, the characteristics of power fluctuation in distributed power generation are analyzed, and the system output is divided into three types: steady-state fluctuation power, peak fluctuation power and reciprocating fluctuating power, and according to the requirements of system power fluctuation, the system output is divided into three types: steady-state fluctuating power, peak fluctuating power and reciprocating fluctuating power. It is found that the supercapacitors and lead-acid batteries complement each other, and the hybrid energy storage system can effectively swallow and puff the fluctuating power and improve the power quality of the microgrid. Then, the composite structure of different energy storage elements is compared and analyzed, and the two-stage parallel structure with bi-directional DC/DC converter is determined as the composite structure of hybrid energy storage system of centralized micro-grid. Then, a three-layer control model is designed, which is composed of real-time state layer, logical operation layer and system control layer. Among them, the real-time state layer is mainly used to collect the power fluctuation signal and the charging state of the supercapacitor, and make the charge and discharge rules based on the principle of power huff and puff of supercapacitor. Logical operation layer provides control object library and control algorithm library to retrieve preset library. The control objects under different charge and discharge states of supercapacitor and battery can be obtained by retrieving the control object library, and then the control object is transferred to the control layer of the system, and the control algorithm library is retrieved by the system control layer. The adaptive control algorithm can be obtained, and then the hybrid energy storage system can be controlled harmoniously by the duty cycle of the pulse width modulated bidirectional DC/DC converter. At the same time, the self-tuning fuzzy PI controller is introduced in the system control layer instead of the traditional PI controller as the auxiliary, which can stabilize the nonlinear fluctuation of power and optimize the operation of the system. Finally, this paper uses the Matlab/Smiulink simulation platform to build the model of the solar microgrid for calculation and simulation, which proves that the proposed hierarchical fuzzy control strategy can effectively stabilize the DC voltage of the energy storage system and suppress the power fluctuation of the distributed power supply. To ensure the stable operation of microgrid grid-connected and islanding mode, and to realize the smooth transition of load switching.
【学位授予单位】：西安理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM727

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