双馈抽水蓄能机组建模理论及控制规律研究

发布时间：2018-12-18 06:59

【摘要】：随着我国经济的大幅度发展,电网的规模不断扩大,对电能的需求也不仅局限在数量上,对电能质量的需求日益明显,因此抽水蓄能电站在电力系统中的地位将越来越重要。为了充分发挥抽水蓄能机组的调峰、调频能力,采用双馈电机替代同步电机,通过变频器调节转子电压的幅值、相位和频率,可以快速调整机组的运行状态,提高机组的效率,增强系统稳定性。本文在分析双馈电机基本理论的基础上,对其变频器的控制策略进行了深入研究,根据抽水蓄能机组的控制设计要求提出相应的控制对策,在Matlab/Simulink仿真软件上完成建模及仿真,验证控制方法的可行性。本文的研究成果有以下几点： (1)分析了双馈电机在不同运行状态下的功率流动规律；分别建立a-b-c静止坐标系和同步旋转坐标系下的双馈电机数学模型。 (2)根据交-直-交变频器的结构,结合矢量控制原理,推导出转子侧有功无功控制、转速无功控制和网侧变频器的解耦方程,分析了定子磁链的观测方法,搭建出控制策略模型,利用Matlab/Simulink仿真软件,建立4kW双馈电机仿真模型,对功率变动、转速调整和定子电压波动情况进行仿真。仿真结果验证了这两种控制方法都可实现解耦控制,控制精度均在2%以内,可在0.01s内快速响应；与传统电机相比在电网电压波动时,可提高电机的稳定性。 (3)通过仿真研究,确定发电工况采用功率优先的控制方式,电动工况采用优先控制转速的方式,以理想水泵水轮机的模型为基础,利用Matlab/Simulink建立250MW机组仿真模型,仿真分析功率变动情况,结果表明机组在发电工况下通过消耗转子的动能可以在1s内调节机组125MW有功功率；电动工况下转速的快速响应也可使水泵的输入有功功率在0.7s内调节125MW,并且在发电和电动工况下可以跟踪最优效率转速,使水泵水轮机始终运行在效率最高点。为双馈抽水蓄能机组的解耦控制提供了理论方法。
[Abstract]:With the rapid development of economy in our country, the scale of power grid is expanding, the demand for electric energy is not only limited in quantity, but also the demand for power quality is more and more obvious, so the status of pumped storage power station in power system will be more and more important. In order to give full play to the capacity of peak shaving and frequency modulation of pumped storage units, a doubly-fed machine is used to replace the synchronous motor. By adjusting the amplitude, phase and frequency of the rotor voltage by frequency converter, the operating state of the unit can be adjusted quickly and the efficiency of the unit can be improved. Enhance system stability. Based on the analysis of the basic theory of the doubly-fed machine, the control strategy of the converter is studied in this paper, and the corresponding control countermeasures are put forward according to the control design requirements of the pumped storage unit. The modeling and simulation are completed on the Matlab/Simulink simulation software to verify the feasibility of the control method. The research results of this paper are as follows: (1) the power flow law of the doubly-fed machine under different operating conditions is analyzed, and the mathematical models of the double-fed machine in the a-b-c stationary coordinate system and the synchronous rotating coordinate system are established respectively. (2) according to the structure of AC-DC-AC converter and the principle of vector control, the decoupling equations of rotor side active and reactive power control, rotational speed and reactive power control and grid side converter are derived, and the stator flux observation method is analyzed. The control strategy model is built, and the simulation model of 4kW doubly-fed machine is established by using Matlab/Simulink simulation software. The power change, speed adjustment and stator voltage fluctuation are simulated. The simulation results show that these two control methods can realize decoupling control, the control accuracy is less than 2%, and the control accuracy is within 0.01s, and the stability of the motor can be improved compared with the traditional motor when the voltage fluctuates in the power grid. (3) through the simulation research, it is determined that the power first control mode is adopted in the power generation condition, and the power priority control speed mode is adopted in the electric condition. Based on the ideal water pump turbine model, the simulation model of the 250MW unit is established by using Matlab/Simulink. The simulation results show that the 125MW active power of the unit can be adjusted within 1 s by consuming the kinetic energy of the rotor. The rapid response of the rotational speed under the electric condition can also make the input active power of the pump adjust 125MWs within 0.7 s, and the optimal efficiency speed can be tracked under the power generation and electric conditions, so that the pump turbine can always run at the highest efficiency. It provides a theoretical method for decoupling control of doubly-fed pumped storage unit.
【学位授予单位】：华北电力大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV743;TV734

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