基于大信号平均模型的buck变换器解耦控制系统设计与研究

发布时间：2018-06-09 14:25

本文选题：DC-DC变换器 + 大信号平均模型　；参考：《广西大学》2017年硕士论文

【摘要】：DC-DC变换器作为开关电源和新能源分布式直流供电系统的核心技术发展十分迅速,目前DC-DC变换器小信号建模并采用线性反馈控制是一种成熟的方法,但这种方法在大信号条件下具有抗干扰能力弱、动态响应性能低的问题。针对以上问题,本文提出两种基于大信号平均模型的Buck变换器解耦控制系统设计方案,包括前馈解耦和前馈-逆系统解耦两种解耦控制系统设计,两种方案均适用于其它DC-DC变换器拓扑结构。提出一种前馈解耦控制系统设计方案。该方案中将电压外环和电流内环作为被控对象,采用逆推法分别设计两个环路的前馈解耦补偿器,使电压外环和电流内环成为两个相对独立的回路。由于消除了电流内环和电压外环的耦合关系,在进行PI调节器参数整定过程中明显比常规双闭环控制器效率更高。为解决前馈解耦控制系统中反馈控制器设计的问题,本文又提出前馈-逆系统解耦控制系统设计方案。该方案中被控对象中的电流内环根据最优化控制理论设计出前馈解耦补偿器;电压外环则采用逆系统理论与解耦控制理论相结合的方式设计逆系统解耦补偿器,将电压环补偿为一阶纯积分环节,并对输入直流电源扰动和负载电流扰动设计前馈解耦补偿器,将两个非线性环路补偿成伪线性系统,再根据最优化控制理论分别对电流内环和电压外环设计线性反馈控制器。同时,为了更明显的体现两种新型控制系统在大信号条件下具有优良的抗干扰能力和动态、静态响应特性,本文根据小信号模型法设计了常规双闭环控制系统。通过matlab/simulink对三种Buck变换器控制系统进行了仿真,验证了本文设计的两种控制系统性能更优,其中前馈-逆系统解耦控制器性能最优。最后,为了进一步验证理论的可行性和控制系统性能的可靠性,基于RT-LAB半实物仿真平台对Buck变换器前馈-逆系统解耦控制方案进行了快速原型实验(RCP),被控对象通过实物实现,即设计制作Buck变换器硬件电路,包括主电路、驱动电路和采样电路;控制器虚拟实现,即前馈-逆系统控制器通过RT-LAB目标机模拟实现,最终得到良好的实验效果,证明了理论的可行性。本文提出的两种方案均是在变换器大信号模型基础上进行,一定程度上解决了大信号条件下的扰动问题,具有较大的理论研究价值和实用价值。
[Abstract]:As the core technology of the switching power supply and the new energy distributed DC power supply system, the DC-DC converter is developing rapidly. At present, it is a mature method to model the small signal of the DC-DC converter and adopt the linear feedback control. However, this method has the problem of weak anti-interference ability and low dynamic response performance under the condition of large signal. In this paper, two kinds of Buck converter decoupling control system design scheme based on large signal average model are proposed, including the feedforward decoupling and feedforward and inverse system decoupling control system design. The two schemes are applicable to other DC-DC converter topology structure. A feedforward decoupling control system design scheme is proposed. As the controlled object, the outer loop and the outer loop are used to design the feedforward decoupling compensator of two loops respectively, which make the voltage outer loop and the current inner loop become two relative independent loops. Because of eliminating the coupling relationship between the current inner loop and the external voltage loop, the double closed loop control of the PI regulator is obviously compared with the conventional double closed loop control. In order to solve the problem of feedback controller design in feedforward decoupling control system, the design of feedforward and inverse system decoupling control system is proposed in this paper. In this scheme, the current loop in the controlled object is designed with the feedforward decoupling compensator based on the optimal control theory, and the external voltage loop adopts the inverse system theory and decoupling control theory. The inverse system decoupling compensator is designed, the voltage loop is compensated to the first order pure integral link, and the feedforward decoupling compensator is designed for the input DC power disturbance and the load current disturbance. The two nonlinear loops are compensated into pseudo linear systems, and then the design lines of the current inner loop and the external voltage loop are separately based on the optimal control theory. At the same time, in order to show the two new control systems with excellent anti-interference ability, dynamic and static response characteristics under the condition of large signal, the conventional double closed loop control system is designed according to the small signal model method. Three kinds of Buck converter control systems are simulated by matlab/simulink. The performance of the two control systems designed in this paper is better, and the feedforward and inverse system decoupling controller has the best performance. Finally, in order to further verify the feasibility of the theory and the reliability of the control system performance, a fast prototype experiment (RCP) for the decoupling control scheme of the feedforward and inverse system of the Buck converter is carried out based on the RT-LAB hardware in the loop simulation platform. The control object is realized by the object, that is, the hardware circuit of the Buck converter is designed and made, including the main circuit, the driving circuit and the sampling circuit. The virtual realization of the controller, that is, the feedforward and inverse system controller is simulated by the RT-LAB target machine, and finally obtains good experimental results, and proves the feasibility of the theory. The two schemes proposed in this paper are all changing. Based on the large signal model of the transducer, it solves the disturbance problem in large signal condition to a certain extent, and has great theoretical research value and practical value.
【学位授予单位】：广西大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP273;TM46

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