可再生能源微电网的建模与控制

发布时间：2018-03-29 00:19

本文选题：微电网　切入点：分布式电源　出处：《广东工业大学》2014年硕士论文

【摘要】：微电网是指由分布式电源、储能装置、负荷、监控单元和保护装置等组成的可实现自我控制、保护和管理的小型自治发配电系统。微电网具有较高的灵活性,可充分发挥高渗透率状态下可再生能源等分布式电源的价值和效益,降低对大电网的影响,是未来电力系统发展的方向。通过几种主要分布式电源及其并网变换器的整体建模,构建含多种分布式电源及储能装置的低压微电网系统模型,分析研究了并网控制与孤岛主从控制策略及运行特性。综合分析了微电网的研究背景和国内外研究现状、运行控制模式及关键研究问题,建立了定桨距永磁直驱风力发电系统定叶尖速比控制的原动机仿真模型；研究分析了几种常见的蓄电池等效电路模型,构建通用电路等效模型的PSCAD仿真模块；建立了光伏电池阵列的标准物理模型,PSCAD仿真结果表明,模型能够很好的反映太阳能光伏电池的输出特性。由并网变换器数学模型导出电流内环控制器的结构框图,结合功率外环,实现并网系统的恒功率控制。根据交流母线处频率和电压的测量值及相关的下垂特性,提出一种基于下垂特性的V/f控制策略,确定分布式电源的有功功率和无功功率输出,为电流环提供参考信号,实现并网逆变器的恒压恒频控制。研究了蓄电池储能单元的控制与太阳能光伏发电系统的MPPT控制,对双向DC/DC变换器Boost工作模式进行建模分析,通过改变占空比实现蓄电池的充放电控制；结合变论域模糊控制算法的插值机理与光伏最大功率跟踪理论,提出一种基于多峰值特性曲线的全局MPPT变论域模糊控制算法。仿真结果表明,算法能快速反映外界环境变化,准确搜索全局最优点,动态运行特性好、稳态精度较高。将文中微电源接入欧盟低压微电网配网系统,形成一个含多种分布式电源与储能装置的微电网系统,构建以蓄电池为主电源,其他分布式电源为从电源的微电网主从控制的仿真模型。对微电网系统在外界环境发生变化时分布式电源接入点及并网稳态运行时的运行特性、微电网在孤岛和并网两个运行模式之间的转换以及孤岛模式下的暂态运行等方式下的电压、频率变化等特征进行模拟仿真,仿真结果表明,所提恒功率控制和恒压恒频控制能够实现微电源功率解耦,维持系统功率输出稳定；以蓄电池为主电源的主从控制策略能有效维持系统功率平衡,微电网运行模式切换时的系统电压和频率也可迅速恢复到稳态设定值,较好地满足了微电网运行要求,验证了控制策略的正确性和有效性。
[Abstract]:Micro-grid is a small self-control, protection and management autonomous distribution system composed of distributed power generation, energy storage device, load, monitoring unit and protection device. It is the direction of power system development in the future to give full play to the value and benefit of distributed generation such as renewable energy under the condition of high permeability, and to reduce the influence on large power grid. Through the whole modeling of several main distributed power sources and their grid-connected converters, A low voltage microgrid system model with multiple distributed power sources and energy storage devices is constructed. The grid-connected control strategy and islanding master-slave control strategy and operation characteristics are analyzed and studied. In this paper, the research background of microgrid, the research status at home and abroad, the operation control mode and the key research problems are comprehensively analyzed, and the prime mover simulation model of constant tip speed ratio control of fixed pitch permanent magnet direct drive wind power generation system is established. In this paper, several common equivalent circuit models of battery are studied and analyzed, and the PSCAD simulation module of general circuit equivalent model is constructed, and the standard physical model of photovoltaic cell array is established. The model can well reflect the output characteristics of solar photovoltaic cells. The structure block diagram of the current inner loop controller is derived from the mathematical model of the grid-connected converter. Combined with the power outer loop, the constant power control of the grid-connected system is realized. A V / F control strategy based on droop characteristics is proposed to determine the active and reactive power output of the distributed power generation, which provides a reference signal for the current loop. The constant voltage and constant frequency control of grid-connected inverter is realized. The control of battery energy storage unit and the MPPT control of solar photovoltaic system are studied, and the Boost working mode of bi-directional DC/DC converter is modeled and analyzed. The charging and discharging control of battery is realized by changing duty cycle, and the interpolation mechanism of variable universe fuzzy control algorithm and the theory of photovoltaic maximum power tracking are combined. A global MPPT variable domain fuzzy control algorithm based on multi-peak characteristic curve is proposed. The simulation results show that the algorithm can quickly reflect the changes of the external environment, search the global optimum accurately, have good dynamic operation characteristics and high steady-state accuracy. In this paper, the micro-power supply is connected to the EU low-voltage microgrid distribution system to form a microgrid system with a variety of distributed power sources and energy storage devices. Other distributed power sources are the simulation models of master and slave control of microgrid with slave power. The operating characteristics of distributed power access point and grid-connected steady-state operation when the microgrid system changes in the external environment are studied. The characteristics of voltage and frequency change of microgrid under island and grid-connected operation modes and transient operation in isolated island mode are simulated. The simulation results show that, The proposed constant power control and constant voltage constant frequency control can realize the power decoupling of the micro power supply and maintain the power output stability of the system, and the master-slave control strategy with the battery as the main power source can effectively maintain the power balance of the system. The voltage and frequency of the system can be restored to the steady state quickly when switching the operation mode of the microgrid, which meets the requirements of the operation of the microgrid and verifies the correctness and effectiveness of the control strategy.
【学位授予单位】：广东工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM732

【引证文献】