基于下垂控制的低压微网逆变器控制策略研究

发布时间：2018-06-21 19:18

本文选题：微电网 + 下垂控制　；参考：《广西大学》2016年硕士论文

【摘要】：微电网是建设未来第三代电网的动力源和有效手段。微电网的控制策略在微网技术中具有重要地位,它可以实现整个电网的高可靠性、高冗余性和可扩展性。本文针对低压微电网,对传统的P-V下垂控制策略进行分析、改进、仿真研究和实验验证。具体研究内容如下：首先分析了光伏系统、储能系统的结构和基本原理,并对其进行了建模。光伏系统采用扰动观察法实现光伏电池的最大功率点跟踪,利用Boost电路控制光伏输出电压。储能系统通过双向DC/DC变流器实现蓄电池的充放电控制。仿真表明,搭建的光伏系统和储能系统能保证直流电压的稳定输出,可有效地用于微电网控制策略的研究。其次,分析研究了传统的下垂控制方法的原理,利用MATLAB/Simulink软件实现传统P-V下垂控制策略的建模。针对采用传统的P-V下垂控制策略存在功率难以准确分配和受负荷影响较大等问题,本文在两方面对其进行了改进。其一,在下垂控制器中引入自调节下垂系数环节,通过动态调整下垂系数来更好地实现功率分配；其二,电压电流双环控制部分引入具有参数自学习能力的简化情感控制器,电压电流双环的参数能够根据被控对象的变化而实时调整,抑制功率振荡和减少负荷变化带来的电压波动,改善系统的动稳态性能。最后对P-V下垂控制策略进行了仿真分析和实验验证。搭建含光伏系统、储能系统的微电网仿真模型,对传统的P-V下垂控制策略和改进的P-V下垂控制策略进行了仿真分析。仿真结果表明,改进的P-V下垂控制策略的微电网系统的功率均分能力、抗干扰能力、动态性能和稳态精度均优于传统P-V下垂控制策略。搭建基于dSPACE的P-V微网下垂控制策略实验平台,利用dSPACE实现两台分布式电源P-V下垂控制算法的编程和测试,控制微电网系统的实物对象。实验结果表明,分布式电源能平滑并联,系统按容量比例分配功率。
[Abstract]:Microgrid is the power source and effective means to construct the third generation grid in the future. The control strategy of microgrid plays an important role in microgrid technology. It can achieve high reliability, high redundancy and scalability of the whole power network. In this paper, the traditional P-V droop control strategy for low voltage microgrid is analyzed, improved, simulated and verified by experiments. The main contents are as follows: firstly, the structure and basic principle of photovoltaic system and energy storage system are analyzed and modeled. The maximum power point tracking of photovoltaic cells is realized by perturbation observation method, and the output voltage of photovoltaic cells is controlled by boost circuit. The charge and discharge control of storage battery is realized by two-way DC / DC converter in energy storage system. The simulation results show that the photovoltaic system and the energy storage system can guarantee the steady output of DC voltage and can be effectively used in the study of control strategy of microgrid. Secondly, the principle of traditional droop control method is analyzed and studied, and the modeling of traditional P-V droop control strategy is realized by MATLAB / Simulink software. Aiming at the problems of the traditional P-V droop control strategy, it is difficult to allocate power accurately and is greatly affected by load, so this paper improves it in two aspects. First, the self-regulating sag coefficient is introduced into the droop controller to achieve better power distribution by dynamically adjusting the sag coefficient; second, the voltage and current dual-loop control part introduces a simplified emotional controller with parameter self-learning ability. The parameters of the voltage and current double loop can be adjusted in real time according to the change of the controlled object, which can suppress the power oscillation and reduce the voltage fluctuation caused by the change of load, and improve the dynamic and steady performance of the system. Finally, the P-V droop control strategy is simulated and verified by experiments. The simulation model of microgrid with photovoltaic system and energy storage system is built. The traditional P-V droop control strategy and the improved P-V droop control strategy are simulated and analyzed. The simulation results show that the improved P-V droop control strategy is superior to the traditional P-V droop control strategy in power sharing ability, anti-jamming ability, dynamic performance and steady-state precision. An experimental platform of P-V microgrid droop control strategy based on DSpace is built. Two distributed power source P-V droop control algorithms are programmed and tested using DSpace to control the physical objects of microgrid system. The experimental results show that the distributed power supply can be smoothly connected in parallel, and the power is distributed according to the capacity of the system.
【学位授予单位】：广西大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TM464

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