【作者】 张璐；

【导师】 李世华； 杨俊；

【作者基本信息】 东南大学 ， 控制科学与工程， 2017， 硕士

【摘要】 随着电力电子技术的高速发展,开关电源在现代工业各个领域的作用越来越重要,人们对开关电源性能的要求越来越高。DC-DC变换器作为一种典型的开关电源,在工业中得到了广泛应用。研究设计具有好的动、静态特性的DC-DC变换器控制算法具有重要的理论意义和实际应用价值。在众多非线性控制方案中,滑模控制的DC-DC变换器具有动态响应好、鲁棒性强的优点。本文以DC-DC变换器中典型的Buck变换器和Buck-Boost变换器为研究对象,设计先进的滑模控制策略。本文的研究内容如下:一、分别介绍Buck变换器和Buck-Boost变换器的工作原理,利用基尔霍夫电压、电流定律描述系统的状态,运用状态空间平均法分别建立两种变换器的数学模型。二、针对Buck变换器系统的输出电压控制问题,基于Buck变换器的状态空间模型,设计了有限时间收敛的无电流传感滑模控制算法。首先,在无法直接测得Buck变换器电感电流信息的情况下,设计了有限时间状态观测器以估计电感电流值。其次,将电感电流的估计值引入控制器的设计中,利用齐次性滑模理论,直接选取实际输出电压与电压期望值的误差作为滑模面,设计了无电流传感滑模控制器,并且给出了闭环系统有限时间稳定性分析。最后,通过仿真和实验进一步验证了无电流传感控制算法控制Buck变换器的有效性和可行性。三、针对Buck-Boost变换器负载扰动下的输出电压控制问题,设计了基于干扰观测的滑模控制算法。首先,为估计系统的干扰,结合Buck-Boost变换器系统的数学模型,设计了非线性干扰观测器。其次,利用传统滑模控制理论,并将干扰的估计值引入控制器的设计中,设计了滑模控制器,通过控制变换器电感电流渐近到达期望值,从而间接控制输出电压到达期望值。最后,通过仿真证实了该复合控制算法的控制性能。四、为进一步提高Buck-Boost变换器系统的控制性能,设计了基于有限时间干扰观测器的非奇异终端滑模控制算法。首先,对Buck-Boost变换器的原始数学模型进行精确反馈线性化处理得到其线性模型。其次,基于其原始数学模型设计了有限时间干扰观测器以得到系统干扰的估计值。再次,针对Buck-Boost变换器的精确反馈线性化模型设计了非奇异终端滑模控制器,实现了对Buck-Boost变换器系统输出电压的有限时间控制。最后,对所设计的控制算法进行了仿真,仿真结果充分证实了算法的优越性。更多还原

【Abstract】 With the rapid development of power electronics technique,in the field of modern industry,switching power supply plays a more and more important role.The performance requirements of switching power supply are getting higher and higher.DC-DC converter serves as a typical switching power supply,and has been widely used in the industry.It is of great throretical and practical value to study control algorithm with good dynamic and static characteristics for DC-DC converter.Among many nonlinear control methods,sliding mode control for DC-DC converter has the advantages of good dynamic response and strong robustness.In this paper,advanced sliding mode control strategies are designed for typical buck converter and buck-boost converter.The research contents of this paper are as follows:Firstly,the working principles of buck converter and buck-boost converter are introduced respectively in this paper.The states of converter systems are described by Kirchhoff’s voltage and current law,and then the mathematical models of the two converters are established by using the state space averaging methods.Secondly,for the output voltage control problem of the buck converter system,a current sensorless sliding mode control method,which can convergence in a finite time,is proposed based on the state space model of buck converter.In the case where inductor current information of buck converter can not be directly obtained,a finite-time state observer is designed to estimate the value of inductor current.Then,the estimation of inductor current is introduced in the controller design,and a current sensorless sliding mode controller is designed by using homogeneous sliding mode theory.The error of practical output voltage and the desired value is taken as the sliding manifold directly.The finite time stability analysis of the closed system is given in this paper.The simulations and experimental results are given to illustrate the effiveness and feasibility of the current sensorless control method for buck converter.Thirdly,for the output voltage control problem of buck-boost converter in load variations,a sliding mode controller based on disturbance observer is designed.In order to estimate the disturbance,a nonlinear disturbance observer is designed based on the mathematical model of buck-boost converter.Then,A sliding mode controller is designed by using the conventional sliding mode control theory and introducing the estimation of disturbances into the design of the controller.The inductor current of the converter is driven to reach the desired value asymptotically,then the output voltage reaches the desired value asymptotically.Simulations are carried out to validate the control performance of the composite controller.Finally,to further improve the control performance of the buck-boost converter system,a finite-time disturbance observer based nonsingular terminal sliding mode control method is designed.The exact feedback linearization model is obtained by nonlinear coordinate transformation based on the original mathematical model of buck-boost converter.A finite-time disturbance observer is designed to estimate the disturbance from load variations.Then,a nonsingular terminal sliding mode controller is designed for the exact feedback linearization model of the buck-boost converter,which achieves the goal of driving the output voltage of buck-boost converter to the desired value in a finite time.The effectiveness of the proposed method is validated by simulation results.更多还原