【作者】 李刚；

【导师】 程时杰； 文劲宇；

【作者基本信息】 华中科技大学 ， 电力系统及其自动化， 2007， 博士

【摘要】 柔性功率调控装置(FPC)是一个大容量的飞轮储能系统。它由储能电机和作为交流励磁电源的电压源型双PWM变流器组成。类似于超导磁储能(SMES)装置,FPC具有独立进行有功和无功功率调节的能力,可以用来提高电力系统稳定和改善电能质量。与SMES相比,FPC易于开发和运行,成本也低。本文讨论了FPC的原理、建模、控制、仿真以及样机研制等各方面的内容。以FPC的静态等值电路为基础,分析了转子交流励磁对FPC运行的影响。研究了FPC的不同工作状态以及在各种工作状态下FPC的能量传递关系。鉴于标量分析方法在FPC控制应用中的不足,推导了储能电机在多种坐标系中的数学模型。通过坐标变换,三相静止坐标系中多变量、高阶、非线性和强耦合的储能电机模型在两相同步旋转坐标系中得到了简化。研究了电网侧VSC变流器和转子侧VSC变流器的数学模型和控制策略。考虑到FPC经常工作在电力系统发生扰动的情况下,提出了一种改进型的定子磁链定向控制策略,该策略对电网电压波动具有更好的鲁棒性,并且易于实现。此外,还讨论了FPC的转速控制策略以及FPC励磁系统的综合控制方案。通过时域仿真研究了FPC的运行特性,验证了前文中讨论的FPC工作原理和控制策略。分析了转子电流、电压和功率限制对FPC功率极限的影响,指出FPC的功率极限主要受转子侧励磁电流的限制。此外,还讨论了FPC的励磁特性,FPC控制系统的稳定性和动态性能以及FPC稳态运行点的选取问题。提出了FPC的两种起动方法和相应的控制策略。此外,还讨论了VSC变流器可能出现的特殊运行状态。在此基础上,给出了电力系统故障时FPC的控制技术。建立了一个包含一台同步发电机和一台FPC的双机无穷大母线系统模型,通过特征值方法对系统的阻尼特性进行了分析。指出FPC的加入可以增加电力系统的总阻尼,特别是机电模式的阻尼,并增强系统的阻尼协调能力。由于FPC能够同时进行电压控制和阻尼控制,因此在电力系统的多目标协调控制方面具有更好的性能,对电力系统的暂态稳定性和小干扰稳定性都有显著改善作用。研制了一台10kW容量的FPC样机。样机包括储能电机本体、变频器及励磁控制系统和FPC的实时监控系统。此外,还给出了样机实验结果。更多还原

【Abstract】 Flexible Power Conditioner (FPC) is a large-capacity flywheel energy storage system. It consists of an energy storage machine and a voltage-source pulse width modulation (PWM) rectifier-inverter used as an AC exciter. Similar to that of the Superconducting Magnetic Energy Storage (SMES), the FPC can realize an independent active and reactive power control, so it can be used to improve the stability of power system as well as the quality of power supply. Additional advantage of the FPC over the SMES based device is that it is easy to develop and to operate. Therefore, the cost will be greatly reduced. The principle, modeling, control, simulation, development of the prototype for the FPC have been discussed in this dissertation.Based on the static equivalent-circuit of the FPC, the influence of the rotor AC excition on the operation of the FPC is analyzed. Then, the operating states of the FPC and the energy flow in all above states are studied. In order to solve the deficiency of the scalar analytical method in the practical control of the FPC, mathematic models of the energy storage machine in several coordinates are deduced. By the coordinate transformation, the multi-variable, high-order, nonlinear and close coupled machine model in three phase static coordinates is simplified in the synchronous rotary coordinates. .The mathematic models and control strategies of grid-side converter and rotor-side converter are investigated. Considerring the fact that the FPC might be operated in grid disturbance conditions, an improved stator flux linkage orientated control strategy is proposed. This strategy is robust for the grid voltage fluctuation and easy to realize. In addition, the rotor speed control strategy of the FPC and the synthesis schemes of the excitation system are discussed.The operational characteristics of an FPC are investigated by time domain simulations. The effectiveness of the operating principle and the proposed excitation control strategies of the FPC are verified. The effect of rotor current, voltage and power limitation on the power margin of the FPC is analyzed. It was found that power margin of the FPC is mainly determined by the rotor-side excitation current. Besides, the FPC excitation characteristics, the FPC control system stability and dynamic performance and the choice of the FPC steady operating point are also discussed in this chapter.Two kinds of start methods and corresponding control strategy are proposed. In addition, the potential special operating states of VSC converters are studied. For this basis, the ride-through control of the FPC during grid faults is proposed.A two-machine and infinite bus power system model including a synchronous generator and an FPC is established. The damping characteristic of the proposed system is analyzed by eigenvalue method. Research results indicate that the total damping of power system, especially the damping of the electromechanical mode, is increased with the FPC. And the ability to coordinate damping is enhanced by the FPC. As FPC can realize voltage control and damping control simutaniously, it can offer better control performance in multiple objective coordinated control of power system. Also, both the transient state stability and the small disturbance stability of power system can be improved by the FPC.The details of the development for a 10kW prototype FPC are given, which includes the main body of the energy storage machine, the frequency-converter with excitation control system and the real-time supervisory system of the prototype. Besides, the experiment test results of the prototype FPC are given in this chapter.更多还原