40T混合磁体外超导磁体电源的控制器研究与设计

发布时间：2018-01-07 20:25

本文关键词：40T混合磁体外超导磁体电源的控制器研究与设计　出处：《中国科学技术大学》2017年博士论文　论文类型：学位论文

【摘要】：中科院强磁场科学中心在建的40T稳态强磁场装置是由内水冷磁体和外超导磁体两部分构成。本文选题为外超导磁体高稳定度电源控制系统设计。外超导磁体电源最大输出8V/16kA,且要求输出电流纹波为1Oppm以内,输出电压纹波有效值在1%以内。控制系统的设计内容涵盖:被控对象的建模、控制指标的提出、控制系统相关参数的确定、控制方式的选择、控制器的设计。当设计方案确定后,还需要进行模型仿真及实际电路验证,以及执行机构、接口器件等实现。对整个电源系统进行分析得出,对于高稳定度电源最关键的三部分分别是:给定、接口器件(包含测量和反馈部分)及控制算法。此外,其他部分也非常关键。文中都有详细的介绍。首先,对被控对象建模。考虑到成本、控制难易等因素,电源主拓扑结构依然采用的是传统的双反星可控硅整流方案。然而,由于其开关频率较低,而且可控硅导通压降较大不可忽略,所以建立主回路模型有一定的难度。本文结合平均电路法和各种干扰模型,对其建立等效电路模型。并对该模型进行仿真,与实测值进行对比,验证所建立的模型在要求的频率范围内是可信的。其次,是对电源实现高稳定度输出的关键因素及相关技术进行详细论证,包含给定、高精度模拟测量电路、数字控制算法的选择以及同步信号滤波电路等。接下来,结合传统自动控制理论,提出了电源控制系统设计的一般方法。本文针对电源系统的特点,分别对系统响应速度、开环截止频率和系统带宽给出了更符合实际电源系统特性的定义,并提出了求取开环截止频率的简单而实用的方法。此外,重点研究了带LC滤波器的功率变换器,通过画近似闭环bode图的方式,得出其系统带宽是接近LC自然频率的,这对电源控制系统的设计非常有意义。然后,针对超导磁体这一大惯性负载,从对50Hz及100Hz纹波的有效补偿及降低对ADC采样频率要求的角度,提出了双环控制架构,其中电流外环采用数字控制方式。本文对双环结构做了深入分析,并提出了双环控制器设计的一般准则。数字外环的控制算法采用RST算法,本文给出了详细的算法原理及参数计算过程。最后,控制系统的具体实现及调试。其中,调试分为二个阶段进行,一是利用假负载测试电压内环的性能;二是将整个控制系统应用于超导磁体。最终的测量结果证明该控制系统能够实现电源要求,整个设计是可信的。
[Abstract]:40T steady high magnetic field device of strong magnetic field in the construction of the science center is composed of an inner and outer water-cooled magnet superconducting magnet is composed of two parts. The topic of this paper is to design a superconducting magnet power supply control system with high stability. The maximum output of 8V/16kA superconducting magnet power supply, and the output current ripple is less than 1Oppm, the output voltage ripple RMS in 1% within the design of control system. The contents include: object modeling, puts forward the control indicators, determine the relevant parameter control system, control mode selection, the design of controller. The design scheme is determined, but also the need for model simulation and actual circuit verification, and actuator interface devices to realize the whole power supply system. Analysis for the three part, the key to high stability power supply are given, interface devices (including measurement and feedback part) and control algorithm. In addition, other Part is also very critical. Described in detail in this paper. First of all, the modeling of the controlled object. Considering the cost, control difficulty and other factors, the main circuit topology is still the traditional double reverse star SCR scheme. However, due to its low switching frequency, and thyristor pressure drop can not be ignored, so the establishment of the main circuit model has a certain degree of difficulty. This paper combined with the average circuit method and various interference model, the equivalent circuit model is established. And the simulation of the model are compared with the measured value to verify the proposed model is credible in the specified frequency range. Secondly, on the power supply the key factors to achieve high stability output and related technologies are demonstrated in detail, including given high precision analog measurement circuit, digital control algorithm and synchronous signal filtering circuit. Then, combined with the traditional automatic control In theory, presents a general method for the design of power supply control system. Based on the characteristics of the power supply system, respectively on the system response speed, open loop cut-off frequency and the bandwidth of the system is defined more in line with the actual power system characteristics, and puts forward the calculating open loop cut-off frequency of simple and practical method. In addition, focus on the power converter with LC filter, the approximate closed-loop Bode diagram by the way of painting, the bandwidth of the system is close to the natural frequency of LC, the power supply control system design is very meaningful. Then, for a superconducting magnet the large inertia load from the effective compensation and reduce the 50Hz and 100Hz sampling frequency ripple requirements for ADC point of view, put forward the double loop control structure, in which the current loop using digital control method. This paper made a thorough analysis of double loop structure, and put forward the general guidelines for controller design of double number. The outer ring of the word control algorithm with RST algorithm, this paper gives the algorithm principle and parameters of the calculation process in detail. Finally, the specific implementation and debugging of the control system. The test is divided into two stages, one is the performance of false load test voltage loop; two is the whole control system is applied to the superconducting magnet. The measured results show that the control system can realize the power requirements, the whole design is credible.

【学位授予单位】：中国科学技术大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TL62

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