考虑储能系统的虚拟同步发电机研究

发布时间：2018-01-02 03:14

本文关键词：考虑储能系统的虚拟同步发电机研究　出处：《济南大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着分布式电源技术的发展,大量的新能源分布式电源接入电网。但是分布式电源所采用的并网技术一般比较落后,大多采用电压锁相环或最大功率跟踪等并网方式。这些传统方法并入电网的功率极有可能是垃圾功率。分布式电源系统功率的单向流动性以及高频特性,在电网中分布式电源渗透水平较高或者是同步发电机缺失的条件下,会使整个电网系统惯性缺失,最终会导致电网系统难以抵御电力系统中常见的高频干扰,从而使系统稳定性降低。本文在充分了解同步发电机并网原理的基础上,掌握了逆变器向同步发电机等效过程。重点研究虚拟同步发电机(Virtual Synchronous Generator,VSG)算法的机电方程,分析其具体工程实现方法。绘制算法实现框图,并通过仿真的手段验证建模的有效性以及实现的可行性。并参照同步发电机的控制原理,研究设计相应的功频控制器和励磁电压控制器。并设计了一种通过改变机械功率输入而调节逆变器输出电压相位的预并列控制单元,能够在不进行变压器隔离的情况下,实现变流器快速平滑的并网。研究了铅酸蓄电池的充放电特性,并确定蓄电池单元的建模方法。在此基础上选择合适的双向DC-DC电路,用于实现逆变器直流侧与储能电池间双向快速的功率流动。通过充分考虑储能系统的特性,以及充放电深度对铅酸蓄电池寿命的影响,提出了一种既能保证系统并网后对电网频率和电压的有效调控,又能有效的保护蓄电池的协调控制策略,使其能够满足运行的经济性。为了更加充分地说明控制策略的优越性,建立了蓄电池的寿命损耗模型,把蓄电池运行过程的寿命消耗进行量化。本文通过对虚拟同步发电机的传统功频下垂控制器进行改进,设计得到一种变下垂系数的虚拟同步发电机功频控制器。其以电池的实时荷电状态(State of Charge,SOC)和运行工况作为输入量,在虚拟同步发电机系统并网运行的过程中,动态地调整功频控制器的下垂系数,从而间接控制系统出力。改进后的变下垂系数控制方法能够在蓄电池即将过充或过放的情况下,对系统并网出力进行调整,最终能够有效抑制过充和过放的发生。本文充分考虑蓄电池侧储能系统的设计,将储能侧的相关特性与逆变器侧的逆变并网有效的结合起来,而不是像之前虚拟同步发电机的相关研究一样,将直流侧忽略或者理想化。整个系统适用性强,非常有利于工程实现。在上述工作的基础上,利用Matlab/Simulink进行系统仿真,构造了整个虚拟同步发电机并网系统的仿真模型,验证了本文所构造系统各部分的性能。仿真结果表明,其能够在满足运行经济性的前提下,有效地参与微电网电压和频率的智能调控。
[Abstract]:With the development of distributed generation technology, new energy and distributed power grid. But a large number of distributed power grid technology used in general is relatively backward, mostly adopts voltage PLL or MPPT and grid method. The traditional method of power grid is likely to be a garbage power. The unidirectional flow and high frequency characteristics of power distributed power the system in the power grid, distributed power penetration level is higher or the synchronous generator under the condition of the absence of, will make the whole power system inertia will eventually lead to lack of high frequency interference grid system is difficult to resist the power system in common, so that the stability of the system is reduced. This paper based on a full understanding of the principle of synchronous generator grid on the master the inverter equivalent to the synchronous generator. The process focuses on the virtual synchronous generator (Virtual Synchronous Generator, V SG) electromechanical equation algorithm, realization method of analysis of the specific project. Rendering algorithm flowchart, and by means of simulation verify the validity of the modeling and the feasibility of realizing control principle. And in the light of the synchronous generator, the design of the corresponding power frequency excitation controller and voltage controller. Research and design a regulated output voltage of inverter by changing the phase of mechanical power input pre parallel control unit can not be in the transformer isolated condition, realize grid connected converter fast and smooth. The charge discharge characteristics of lead-acid battery, and determine the modeling method of battery unit. Based on the bi-directional DC-DC circuit suitable for the realization of the inverter DC side, and storage battery power bidirectional fast flow. By considering the characteristics of energy storage system, and the depth of the charge and discharge of lead-acid battery life. Ring, to design a effective regulation to ensure the system integration on the grid frequency and voltage, and can effectively protect the battery of the coordinated control strategy, which can meet the economic operation. In order to fully illustrate the superiority of the control strategy, establish the life loss model of the battery, the battery operation process the life consumption was quantified. This paper was improved by traditional power frequency droop controller of virtual synchronous generator, the design of a variable coefficient virtual synchronous generator power frequency controller. The battery state of charge in real time (State of Charge, SOC) and operating conditions as input, in the process of the integrated operation of virtual synchronization the generator system, thecoefficient dynamically adjust the power frequency controller, thereby indirectly control the system output control variable. The improved method can droop coefficient in the battery is The overcharge or overdischarge conditions of grid connected output regulation, finally can effectively inhibit the overcharge and overdischarge. Considering the side design of battery energy storage system, the storage characteristics of inverter side and inverter side are effectively combined, and related research is not like before virtual synchronous generator, the DC side will be ignored or idealized. The whole system has strong applicability, is very conducive to the realization of the project. Based on the above work, the system simulation by Matlab/Simulink, constructed a simulation model of the virtual synchronous generator grid system, to verify the structural performance of each part of the system simulation. The results show that it can meet the premise of economic operation under the intelligent control to effectively participate in the micro grid voltage and frequency.

【学位授予单位】：济南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TM31

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