【作者】 陈仲伟；

【导师】 段善旭； 邹旭东；

【作者基本信息】 华中科技大学 ， 电气工程， 2011， 博士

【摘要】 基于飞轮储能系统的柔性功率调节器(Flexible Power Conditioner, FPC)由双馈感应电机和作为交流励磁电源的双PWM变换器组成。FPC能够独立的进行有功和无功功率调节,拥有储能、发电、调相等多种功能,具有提高电力系统稳定性的能力。与其他储能方式相比,基于飞轮储能的FPC很适合应用于低频率、大容量、长时间的功率补偿应用领域。本文主要从FPC的原理、FPC中双馈感应电机建模、双馈感应电机励磁控制以及FPC在提高提高电力系统稳定性方面的应用等方面进行阐述,主要包括以下部分：本文首先介绍了课题的背景,讨论了各种储能技术的发展及其在电力应用,对FPC的结构和工作原理进行了介绍,并对其中关键技术的研究现状进行了讨论。建立了FPC中双馈电机的数学模型,得到稳态运行条件下等值电路和能量流动关系,详细分析了FPC的各种工作状态。研究了FPC中双馈电机的励磁控制技术。对其电网侧变换器和转子侧变换器的数学模型和控制策略进行了讨论。在EMTDC/PSCAD仿真平台上建立了相应的仿真模型,对FPC运行特性进行了仿真研究,验证了控制策略的正确性和实用性。详细分析了FPC在电网电压对称跌落情况下的故障穿越控制技术。在电网侧变换器控制中加入负载电流前馈,以减小在电网电压扰动过程中直流电压波动。对于转子侧变换器的控制,先从转子开路模型进行了暂态磁链和转子电压的分析,然后建立了考虑转子电流时的双馈电机暂态模型,并得出电机转子侧过电流的原因是由于定子侧的暂态磁链变化所引起。接着利用暂态分析的结论,采用了一种新的励磁控制策略,通过在转子侧变换器励磁控制中加入虚拟阻抗,来抑制转子过电流冲击从而保护转子侧变换器的安全,扩大双馈电机在电网电压跌落时的运行范围。最后通过仿真验证了方案的有效性。探讨了FPC阻尼电力系统功率振荡的机理,提出通过FPC的阻尼控制增大发电机电磁转矩对功率振荡的阻尼效果。设计了FPC抑制发电机功率振荡的阻尼控制器,并在EMTDC/PSCAD仿真平台上建立了FPC接入单机无穷大系统以阻尼发电机功率振荡的仿真研究。考察了FPC在该控制器作用下对电力系统功率振荡的阻尼控制效果。自行研制一套FPC系统实验装置,依托此装置研究了一系列关键问题：对电网侧变换器的启动控制以及正常工况运行时对直流电压的稳定控制进行实验,结果显示电网侧变换器可以对直流电压的稳定起到很好的控制效果,并且能为转子转差功率提供与电网连接的通道,且具有良好的动、静态特性；转子侧变换器对双馈感应电机进行启动控制,速度控制和有功、无功功率的解耦控制,实验结果表明转子侧变换器启动投入平滑,没有过大的电流和功率冲击,FPC能正常运行于超、次同步储能和发电以及调相等工作状态,具有良好的有功、无功功率解耦控制性能；在电力系统动态模拟实验条件下,将FPC接入单机无穷大系统的发电机端口进行阻尼发电机功率振荡的实验研究,实验结果证明FPC具有阻尼发电机功率振荡的作用,以此验证了所设计FPC阻尼功率振荡控制器的可行性,从实践上证明了对FPC阻尼系统功率振荡机理分析的正确性。为进一步开展FPC在电力系统的其它应用研究,提供了物理实验平台。更多还原

【Abstract】 The Flexible Power Conditioner (FPC) incorporates the functions of the synchronous condenser and flywheel energy storage. It is made up of a doubly-fed induction machine connected with flywheel, a back-to-back converter for AC excitation and an excitation vector control system. The advantage of FPC is its capacity of controlling both active and reactive power, and it have the storage, generate and synchronous condenser operating mode.So it can be used to improve the stability of power system.Additional advantage of the FPC over the other storage system is that it is suitable for power compensation of low frequence, large capacity and long time.The principle, modeling, and applications in power system of the FPC have been discussed in this dissertation.The dissertation consists of six main chapters as follows:The background of this project is introduced.The energy storage technology and its applications in power system have been discussed. And then, the structure and principle of the FPC are introduced and the key technologies are discussed.The mathematic model of the FPC is discussed.The steady state equivalent-circuit model of DFIG is established and the energy floating of FPC is discussed. Based on the analysis above, the operation of the FPC is analyzed.For this basis, the vector excitation control strategy of the FPC will be discussed detailedly in the next chapter.The vector excitation control strategy of the FPC is researched.The mathematic models and control strategies of a back-to-back converter is discussed. The simulation model of FPC on EMTDC/PSCAD environments is established. At last, simulation results show the effectiveness of the proposed scheme.The control strategy of the FPC during the grid voltage drop is researched.For the grid side converter, the control strategy based on the load current feed-forward is presented to suppress fluctuation of DC capacitor voltage.For the rotor side converter, firstly, the transient flux and rotor voltage from the rotor open model is analyzed.Then, basing on the establishing of the transient model which considering rotor current, we get a conclusion that the transient flux of stator side is the reason of the over-current on rotor side.Based on the conclusion of the transient analysis, a new excitation control strategy was adopted in this paper.To guarantee the safety of the rotor side converter, using the virtual impedance control strategy to suppress the rotor over-current, it can expand the operating range of doubly-fed generator during the grid voltage drop.At last, simulation shows the effectiveness of the proposed scheme.The application of FPC in damping out power system oscillations is discussed.The principle of FPC on damping out power oscillation is analyzed theoretically.It is found that variation of the active power where the FPC is applied is the best signal used for FPC to damp out power system oscillations.The simulation model of FPC used to damp out power system oscillation is carried out and very encouraging results are obtained.At last, it designs and implements a laboratory platform of FPC system with DFIG which main part is a set of a back-to-back converter which is made up of the grid-side converter and rotor-side converter. A lot of experiment items are performed on this platform, which including the grid-side converter control and the rotor-side converter control.Another experiment test of the FPC prototype is used to damp out power system oscillation is carried out in a power system dynamic simulation laboratory environment.The experimental results testify the validity of the theory and the control strategy proposed in this dissertation.更多还原