磁阀式可控电抗器在无功补偿中的应用

【作者】 刘海涛；

【导师】 张卫星；

【作者基本信息】 山东大学 ， 电力电子与电力传动， 2007， 硕士

【摘要】 文中首先简单介绍了电抗器的发展历程，可控电抗器的理论研究及其应用现状。文章中重点对磁阀式可控电抗器(Magnetic-Valve Controllable Reactor，MVCR)做了详细的理论研究，在已有状态方程的基础上，推导出电抗器的等效电路方程，并使用MATLAB建立了等效仿真模型。文中第三章对磁阀式可控电抗器的伏安特性、控制特性、谐波特性及响应特性分别进行了仿真分析，给出各种特性曲线；另一方面，通过公式推导的方式对以上各个特性进行理论分析，做出各种理论分析特性曲线；将模型仿真的结果与理论推导公式的结果进行比较，验证了仿真模型的准确性和有效性。在MATLAB仿真模型的基础上，对提高响应速度的方法进行了讨论。从硬件结构上来说，要提高响应速度可以增加电抗器的抽头比、直流预偏磁、电容放电振荡等；从控制策略上来讲，可以通过增加电抗器的导通角来提高响应速度，但这仅适用于非满负荷运行的状况。文中选择了一种增加抽头比来提高响应速度的方式，使直流控制电压变为2倍，相应的晶闸管导通角范围变为0～90度；文中从控制特性的线性度、有功损耗、谐波特性等方面进行分析。结果显示，增加抽头比后控制特性由原来的近似余弦变为近似线性，谐波特性保持不变，有功损耗没有增加。通过MABLAB对增加抽头比的电抗器进行仿真分析，采用适当的启动控制方法，达到额定输出状态时响应时间减少一半，约0.15s；当要求电抗器输出电流越小时，在2倍电压下启动，响应速度越快。文中对通过电容放电来提高响应速度的方法进行了分析，包括控制回路电感的非线性问题、最佳振荡周期选取问题，以及电容充电的控制策略问题。通过基于MATLAB的模型仿真表明，带有电容充放电的MVCR，可将响应时间缩短到一个甚至半个工频周期，可以从根本上解决电抗器响应速度慢的问题。但使用电容充放电也存在很多问题，如充电电压过高、确定预充电电压值等，需要进一步解决。最后，文章将提高响应速度后的MVCR应用到电气化铁道动态无功补偿中，使用MVCR+FC进行动态补偿，在动态补偿效果、响应时间、功率因数等几个方面，对2倍电压控制方式、电容放电控制方式与普通控制方式的补偿效果进行了比较分析。结果表明2倍电压控制方式可以从一定程度上提高响应速度，特别是当要求输出电流较小时，可以在几个周期内完成响应过程。电容放电控制方式，可以从根本上解决提高响应速度的问题，响应时间可提高到0.01s，且动态补偿效果良好。更多还原

【Abstract】 Firstly, the development history of reactor was introduced in this paper; the research achievements recently and the application of reactor were also mentioned in this paper. The basic theories of Magnetic-Valve Controllable Reactor (MVCR) were analyzed in chapter two. On the basis of state equations, the equal circuit equations were got, then using the software of MATLAB to construct emulate model. In chapter three, the characteristics of volt-ampere, control, harmonics and response were emulated, the curve of every characteristics were presented in this chapter. On the other hand, we analyzed the characteristics in the form of formulations. Then we compared two kinds of results to validate the veracity and validity of the model.On the basis of MATLAB emulation model, we discussed the methods of improving response-speed. From the point of hardware, increasing the tap-ratio of reactor, using direct current windings in addition or capacitance discharge were all in promotion. From the point of control strategy, we can use the way of increase conduction angle, but this method was just suit to conditions that the load wasn’t full. In this paper a new kind method of increase tap-ratio was promoted, the DC control voltage becomes two times, while the range of conduction angle becomes 0~90 accordingly. This method has a perfect control characteristic, which was almost linearity. The disadvantage was that the active power consumed has a little increase, but not more than 10 percents. In the emulations of MATLAB, response time from zero to rating conditions was just 0.15s, the lower current of MVCR, the faster of the response speed.In chapter four, we also discussed the method of capacitance discharge to improve response speed. The problems of nonlinear inductance in control circuit, the optimal oscillation period and control strategy were all mentioned. The respond time can be condensed to 0.01 second by this way, so we can resolve the problem of low response speed of reactor thoroughly. But there were several problems need to resolve further more, such as the charge voltage is too high.In the last chapter, we applied the MVCR which response speed was improved to electrical railway; MVCR matched with fixed capacitance (FC) was used in reactive power compensation. In the aspects of compensation effects, response time, power factor and so on, we compared and analyzed the methods of promoted in chapter four. The results of emulation indicated the first compensation method can satisfy the demand in a certain extent, the last way can fully satisfy the demand, the dynamic compensation effects were ideal.更多还原