【作者】 韦克康；

【导师】 郑琼林；

【作者基本信息】 北京交通大学 ， 电气工程， 2012， 博士

【摘要】 牵引变流器是轨道交流牵引传动控制系统的核心,它的性能直接影响到了车辆运行的性能。然而,轨道牵引变流器的功率较大、开关频率低、工作环境恶劣等问题,在控制上存在很多难处。长期以来,我国在牵引变流器机组和核心配套技术依赖于进口,制约着我们轨道交通的进一步发展；另一方面,数字控制以其灵活性、可重复性和可靠性等优点,已经取代了模拟控制,广泛应用于牵引传动控制系统。为此,本文以高速电力机车的开发为背景,围绕牵引变流器数字控制的几个重要问题进行深入研究,以提高牵引传动系统的瞬态和稳态性能,并通过仿真和实验研究验证了其正确性。首先,在牵引电机矢量控制系统中,电磁转矩输出性能主要受到转子磁场的幅值和定向角度的影响,而牵引电机参数变化会导致这两个变量失调,所以本文对如何提高矢量控制系统抗参数变化的鲁棒性进行了深入研究。为此,本文在传统间接矢量控制的基础上引入了磁链闭环控制和基于q轴磁链模型的定向角度校正算法。在铁路牵引供电系统中存在着无电的分相区,本文同样分析和讨论了牵引系统在分相区的断电带速重启和再生制动的控制策略,提高牵引控制系统的鲁棒性。其次,对改善电流环数字控制瞬态响应的控制策略展开了深入研究。针对同步旋转坐标系下电流环的耦合问题,本文采用了复矢量PI控制策略,消除dq耦合。接着,又综合分析和比较常见复矢量PI控制器数字实现方式的优缺点。在此基础上,对制约电流环性能的数字延时补偿方法进行了深入研究,提出了相应延时补偿策略和脉宽调制(Pulse Width Modulation, PWM)多次更新算法,进一步消除延时对系统的影响。最后,为了改善高速区低载波比电流谐波过大的问题,本文对优化脉宽调制策略在牵引变流器的应用进行研究,特别是对谐波电流有效值最小PWM技术的角度计算问题作了深入研究,此外,还以特定消谐PWM为例介绍了数字实现方法；接着又研究了对交直交牵引变流器的直流脉动影响的数字抑制方法,采用了周期预测补偿和采样修正相结合的数字补偿方法,形成了纯数字无差拍频控制策略；最后,对不同PWM模式的切换问题进行了深入研究,提出了具体切换原则和方法。更多还原

【Abstract】 Traction converter plays an important role in railway AC drive system, which directed affectes the performance of vehicle. The rail traction’s capacity is larger, the switching frequency is low, and works at poor conditions, so there are many difficulties in the control. However, as a long time, the power converter and core control technologies are stillrelied on importing in our country, which significantly restricts further development of rail transportation. On other hand, due to its flexibility, repeatability and reliability, etc, digital control has replaced the analog control in the field of traction control. Therefor, this article focus on the several important issues in digital control of traction converter in order to improve the transient and steady performance of the traction drives system. Simulations and experiments demonstrate the correctness of the research results. Following are the major researchworks of this dissertation.Firstly, in field oriented control system of traction motor, there are two important factors (the rotor flux amplitude and orientation angle) that restricting the torque output performance while the variation of traction motor parameters will decline the control performance, so how to improve the vector control robustness of the system is in-depth researched. Therefore, the closed-loop control of flux and the q-axis flux model orientation angle correction algorithms are introduced based on the traditional indirect vector control in this paper, and some issues of the strategy are also discussed. What’s more, two kinds of the strategy of traction motor control at neutral section are discussed in order to improve system robustness.Sencondly, the current loop digital control strategy is discussed, in order to improve the transient performance of current loop. The voltage coupling problem of vector control system is thoroughly analyzed and the complex vector PI controller is introduced to destroy the decoupling. And the different digital realized method of complex vector PI controller are discussed and compared. On this basis, the digital delay is in-depth discussed; the delay compensation strategy and a new PWM update algorithm are presented to further eliminate delay on the system.Finally, in order to improve the harmonic content at the low-carrier ratio, the optimized pulse width modulation strategy for traction converter application is discussed. The selective harmonic elimination PWM technique and harmonic current RMS minimum PWM method are studied, in particular, the calculation of harmonic current RMS minimum PWM method is showed and the comparing of two methods is explained in detail. And then, the digital beatless control compensating the fluctuating DC link voltage for AC-DC-AC converter is discussed, using the repetitive forecast and the sampling compensation method; finally, the transition method between different PWM modes is proposed.更多还原