【作者】 许飞；

【导师】 何湘宁； 马皓；

【作者基本信息】 浙江大学 ， 电气工程， 2009， 博士

【摘要】 随着电力电子技术的飞速发展以及用户对电能质量要求的提高,逆变器在许多领域的应用越来越广泛,对逆变器的控制性能要求也越来越高。滑模变结构控制本质上是一类特殊的非线性控制技术,其具有稳定范围宽、动态响应快、对参数变化和扰动不敏感等优点。从逆变器本身的开关工作特性来说,它正是周期性的变结构系统,滑模变结构控制策略是对它具有强适用性的控制方式。论文在总结、归纳现有的逆变器控制技术基础上,围绕逆变器的滑模变结构控制技术展开研究,提出了几种连续和离散时间系统的滑模变结构控制策略,并将其分别应用到Buck电压型组合式逆变器和电流源逆变器中,取得了比较好的控制效果。其中,电流源逆变器被应用于继电保护测试仪中,该测试仪是在继电保护装置投入运行或检修时,对继电保护装置的各项性能指标进行严格的测试,以保证电力系统的安全稳定运行。首先,论文提出了一种应用于Buck型组合式逆变器的连续三阶滑模变结构控制策略。在传统的比例微分二阶滑模的基础上,加入了输出电压偏差的积分环节,使系统本质上消除了稳态误差,同时保证相应的动态性能。文中采用李导数分别给出了二阶和三阶滑模变结构控制器详细的分析和设计,与传统的分析和设计方法相比,该方法使整个过程更加简明、更具系统性。文中采用映射法详细分析了三阶滑模变结构控制策略的滑模运动和滑模切换区,给出了其滑模面系数的具体选取方法。论文分别给出了上述两种控制策略的对比实验,实验结果证明了分析和设计的正确性。其次,论文详细讨论了基于三种常用的离散趋近率的滑模变结构控制策略,在此基础上设计了基于离散变速趋近率的滑模变结构控制策略,并将其应用到电流源逆变器系统中,该控制方法使系统对参数变化和外部扰动具有较好的动态响应,而且使系统能够渐近稳定于原点。基于电流源逆变器系统的动态模型,论文给出了该离散滑模变结构控制器的具体设计过程,同时详细分析设计了该控制器的离散滑模切换区,并在此基础上给出了离散滑模面系数和趋近率参数的选取范围。建立了Matlab/Simulink仿真模型以及实验样机,对基于离散等速趋近率和离散变速趋近率的滑模变结构控制器进行了仿真和实验比较。为了解决离散变速趋近率动态响应和系统抖振之间的相互影响,本文进一步提出了一种新颖的基于衰减变速趋近率的离散滑模变结构控制策略。该控制方法既保留了离散变速趋近率的优点,又加快了系统的渐近稳定速度,同时减小了系统的抖振。论文将该控制策略应用到电流源逆变器系统,分析设计了离散滑模切换区的范围,同时讨论了该控制器各个系数的选取范围,使系统能够渐近稳定于原点,且保证该离散滑模变结构控制策略满足滑模条件和收敛条件。仿真和实验验证了基于离散衰减变速趋近率控制的电流源逆变器系统具有良好的动态性能以及对外界扰动和参数变化良好的鲁棒性。然后,论文将状态预测观测器引入离散滑模变结构控制器中,基于离散时间系统能控性和能观性的基本理论,提出了基于状态预测观测器的离散滑模变结构控制策略。该方法利用状态观测器对系统的状态变量进行超前一拍预测,获得超前一拍控制量,较好地解决了数字控制一拍滞后的问题,从而更好地改善了基于离散滑模变结构控制的系统动态性能和稳定性。在电流源逆变器系统离散状态空间方程的基础上,利用状态反馈极点配置理论,文中详细给出了状态预测观测器系数矩阵的设计过程。在实验样机上对文中所提出的控制策略进行了具体的实验验证,实验结果证明了分析和设计的正确性。最后,论文将滑模变结构控制和无源性控制相结合,提出了一种新颖的离散无源性滑模变结构控制策略。利用无源性控制的控制方法简单、鲁棒性好等优点,较好地减小了离散滑模变结构控制系统的抖振。基于动力学能量观点,文中分析和设计了电流源逆变器系统的欧拉-拉格朗日模型,并在此模型的基础上,给出了离散无源性滑模变结构控制器的详细设计过程,利用李亚普诺夫稳定性原理证明了该系统的全局稳定性。同时,我们将无源性控制方法和滑模变结构控制方法进行对比分析,利用两种控制方法控制律的相似性,提出了一种可行的阻尼项系数的选取方法。实验验证了上述新型控制策略的正确性。更多还原

【Abstract】 With a fast development of power electronics and the advancement of required power quality, inverters have been applied to more and more fields. And the control performance of inverters becomes much higher. Sliding mode control (SMC) strategy was introduced initially for variable structure systems (VSS) which is well-known for its several advantages such as wide stability range, robustness for disturbance of system, and good dynamic response. Characterized by switching, inverters are inherently variable structured. Therefore, it is appropriate to apply SMC to inverters.Based on the overview of the existing control techniques, this dissertation mainly focuses on the SMC for inverters and has presented several novel continuous- and discrete-time SMC strategies, which are applied to Buck inverter and current-source inverter (CSI) respectively. The CSI is one of the most important circuit in the relay protection testing equipment. This testing equipment is used for the performance testing of the relay protection equipment. It is a very important guarantee for the safe operation of power network.Firstly, a novel third-order continuous-time SMC strategy for Buck inverter is proposed in this dissertation. Based on traditional second-order SMC, integral action is introduced into the sliding surface to eliminate the steady state error and maintain the dynamic performance of Buck inverter. The proposed control strategy is discussed detailedly based on the Lie derivative method. The geometry associated with the sliding mode control is easy to understand and could be particularly exploited in circuits which are designed to exhibit a time scale separation property. To simplify the analysis, three-dimensional trajectory transforms into the two-dimensional one through mapping method. The sliding motion is described by phase trajectory vividly. And the selection of the sliding surface coefficient is presented. Experimental results of these two continuous-time SMC strategies are included to validate the analysis.Then, three common discrete-time SMC strategies based on reaching law are discussed in this dissertation. A discrete-time SMC strategies based on variable rate reaching law is designed and applied to the CSI system. The proposed control strategy provides excellent robustness with regard to external disturbances and great dynamic response, and ensures that the system converges to original point asymptotically. Base on the model of the CSI system, the design process of the sliding mode controller is presented. The sliding domain and sliding surface coefficient are designed in detail. To illustrate the properties of the proposed control strategy, a numerical example is studied here using Matlab/Simulink. A prototype of the DSP-based CSI system has been built in the laboratory to verify the proposed control scheme experimentally.In order to figure out the conflict between the dynamic response and the chatting of the variable rate reaching law, a novel discrete-time SMC is presented which is called the attenuating variable rate reaching law. It not only has the advantage of reaching the original point asymptotically, but also can force the state vectors into the sliding domain quickly and reduce the chattering of the system greatly. It is applied to the CSI system. The sliding domain and the sliding surface coefficient are analyzed to ensure that the system converges to original point asymptotically. Simulation and experiment results would be shown that the proposed controller could offer good dynamic response and insensitivity to disturbances and parameter variations.Furthermore, the state predictive observer is introduced into the discrete-time SMC based on the controllability and observability of system. The proposed control strategy can predict the system variables one beat advanced and solve the delay problem of digital control primely, which greatly improves the dynamic performance and stability of system. Base on the dynamic model of the CSI system, the state predictive observer matrix is designed detailedly using the pole placement theory of state feedback. Final experimental results show that the system has good steady and dynamic characteristics.Last, this dissertation presents a novel discrete-time passivity-based sliding-mode control (PB-SMC) strategy based on the nonlinear control theory. It reduces the chatting greatly of the discrete-time sliding mode controlled system using the advantages of the passivity-based control (PBC). The Euler-Lagrange model of the CSI system is analysed and designed. Based on the dynamic model, the proposed control strategy has been designed detailedly. The stability property is simultaneity accomplished using the Lyaponov theorem. Comparing SMC with PBC, a doable selection of the damping assignment is presented. Final experimental results are demonstrated to validate the theoretical discussion.更多还原