光储微网运行综合控制研究

发布时间：2018-12-08 19:35

【摘要】：随着环保问题、资源紧缺、电网安全和可靠性问题的日益显露,清洁、可再生的分布式能源(Distributed Generation,DG)和分布式发电技术迅速发展。然而,对于电网来说,由于DG对其造成了一定的冲击,导致电网需要采取一定的限制与隔离,这大大减弱了DG的效能。微网的出现协调了DG与电网之间的矛盾。微网逆变器作为微网的重要组成模块,对其进行合理的控制是一个重要的研究领域,是微网系统稳定运行的关键。本文研究光储微网运行的综合控制策略。论文首先分析了光伏电池的数学模型和输出特性,在此基础上提出将二次插值和变步长电导增量法相结合的光伏最大功率跟踪(Maximum Power Point Tracking,MPPT)改进算法,有效地解决了MPPT跟踪速度与稳态波动之间的矛盾。随后,为保证光伏的最大功率输出,在分析PQ控制原理基础上,设计了包含功率外环电流内环双环控制的PQ控制系统,并证明了该控制系统的有效性。其次,分析了三相电压源型逆变器在三相坐标系下、αβ两相静止坐标系下和dq两相旋转坐标系下的数学模型。光储微网系统孤岛运行时,为保证系统电压和频率的稳定,设定储能为主控源。在分析下垂控制和V/f控制原理的基础上,设计了包含下垂控制器和电压电流双环控制器的下垂控制系统和V/f控制系统。仿真结果表明,储能在下垂控制和V/f控制下能为微网提供电压和频率支撑。最后,综合分析主从控制与对等控制的优缺点,在分析光伏控制和储能控制的基础上,研究光储微网运行的综合控制策略。方法如下:光伏系统始终采用PQ控制,保证最大功率输出;在并网运行时,储能装置采用下垂控制,实现“即插即用”;微网转孤岛运行及孤岛运行时,检测微网系统电压和频率偏差并判断是否在允许范围内,从而确定储能装置的控制方式为下垂控制或V/f控制。当储能装置在下垂控制和V/f控制方式之间切换时,采用控制器状态自适应的平滑切换方法。最后设计了包含PQ控制系统、下垂控制系统、V/f控制系统以及状态自适应的切换控制系统的综合控制系统。仿真结果表明综合控制策略可以实现微网系统电压和频率的稳定控制,减少储能逆变器控制方式的切换次数。
[Abstract]:With the problems of environmental protection, shortage of resources, security and reliability of power grid, clean and renewable distributed energy (Distributed Generation,DG) and distributed generation technology are developing rapidly. However, due to the impact of DG on power grid, it is necessary to take some restrictions and isolation, which greatly weakens the efficiency of DG. The appearance of microgrid coordinates the contradiction between DG and power grid. As an important module of microgrid, the reasonable control of microgrid inverter is an important research field and the key to the stable operation of microgrid system. In this paper, the integrated control strategy for the operation of optical storage micronetworks is studied. Firstly, the mathematical model and output characteristics of photovoltaic cells are analyzed. Based on this, an improved photovoltaic maximum power tracking (Maximum Power Point Tracking,MPPT) algorithm combining quadratic interpolation and variable-step conductance increment method is proposed. The contradiction between MPPT tracking velocity and steady state fluctuation is solved effectively. Then, in order to ensure the maximum power output of photovoltaic, based on the analysis of PQ control principle, the PQ control system including power outer loop current inner loop double loop control is designed, and the effectiveness of the control system is proved. Secondly, the mathematical models of three-phase voltage source inverter in three-phase coordinate system, 伪尾 two-phase stationary coordinate system and dq two-phase rotating coordinate system are analyzed. In order to ensure the stability of system voltage and frequency, the storage energy is set as the main control source when the optical microgrid system operates on an isolated island. Based on the analysis of droop control and V / F control principle, a droop control system and a V / F control system are designed, which include a droop controller and a voltage and current double loop controller. The simulation results show that the energy storage can provide voltage and frequency support for the microgrid under droop control and V / F control. Finally, the advantages and disadvantages of master-slave control and peer-to-peer control are comprehensively analyzed. Based on the analysis of photovoltaic control and energy storage control, the integrated control strategy for the operation of optical microgrid is studied. The methods are as follows: the photovoltaic system always adopts PQ control to ensure the maximum power output, while the energy storage device adopts sag control to realize "plug and play"; During the operation of microgrid to island and island operation, the bias of voltage and frequency of microgrid system is detected and whether it is within the allowable range, and the control mode of energy storage device is determined to be droop control or V / F control. When the energy storage device switches between the droop control and the V / f control mode, the controller state adaptive smooth switching method is adopted. Finally, an integrated control system including PQ control system, droop control system, V / F control system and state adaptive switching control system is designed. The simulation results show that the integrated control strategy can realize the stable control of the voltage and frequency of the microgrid system and reduce the switching times of the control mode of the energy storage inverter.
【学位授予单位】：郑州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM727

【相似文献】