EAST离子回旋共振加热相位和功率控制系统的研究

发布时间：2018-05-01 04:21

本文选题：离子回旋共振加热 + 鉴相器　；参考：《中国科学技术大学》2017年博士论文

【摘要】：离子回旋共振加热是EAST超导托卡马克核聚变实验装置加热等离子体的重要手段之一,被视为芯部等离子体加热和电流驱动的首选手段。它不仅可以加热电子、离子,还用来控制等离子体某些重要参数的空间分布和产生等离子体极向电流,以及驱动等离子体等。理论计算和实验研究表明,离子回旋天线运行在(0,π)相位时,具有较好的加热效果且产生相对较小的杂质。另外,天线在(0,π/2)相位运行时可以驱动不对称谱,有利于电流驱动的研究。未来在ITER装置上,离子回旋电流驱动将作为驱动芯部电流的重要手段,因而离子回旋天线相位的测量和精确控制无论对于离子回旋加热还是驱动研究都有着重要的意义,如果天线的相位不能够精确测量并加以控制,则可能导致天线电流带之间的功率不平衡,影响加热效果。在EAST放电实验过程中,等离子体的阻抗是随着时间变化着的,这就造成了离子回旋共振加热系统射频注入功率的波动。在本研究之前,主要是通过手动改变信号源的输出幅度来调节发射机的输出功率,在等离子体放电的一炮之内,虽然信号源的幅度保持不变,但是发射机的输出功率却呈现很大的波动,因而无法实现输出功率的精确控制。本课题的研究内容主要是实现对ICRH系统射频波相位和功率的测量以及闭环反馈控制。论文中对比了几种不同的相位和功率测量方法,在已有的AD8302鉴相器的基础上设计了基于HMC439芯片的鉴相器,该鉴相器具有宽的测量范围(720°)和低的相位噪声,另外好的线性度也给后续的数据处理带来了方便。相位与功率测控系统基于FPGA主控制器,由信号采集板卡和反馈控制板卡组成,信号采集板卡主要负责对相位和功率输入信号的调理以及模数转换,最终在FPGA内部完成数据的拟合计算。反馈控制板的功能是实现对相位和功率的实时反馈控制以及与上位机的通信。我们使用Labview软件来开发上位机程序,而上位机与控制机箱之间的数据收发通信是通过USB协议实现的。通过软硬件的设计和反馈算法的不断优化,相位与功率反馈控制系统分别在假负载和等离子体放电环境下完成测试,目前已成功应用于2016年的EAST实验,在负载阻抗变化的情况下,相位和功率根据闭环反馈算法,自动稳定在上位机设定的目标值,为功率和相位调制实验的开展奠定了基础。
[Abstract]:Ion cyclotron resonance heating is one of the most important methods for plasma heating in EAST superconducting tokamak nuclear fusion device and is regarded as the preferred method for core plasma heating and current driving. It can not only heat electrons and ions, but also control the spatial distribution of some important parameters of plasma, generate plasma poloidal current, and drive plasma. The theoretical calculation and experimental study show that the ion cyclotron antenna has good heating effect and relatively small impurity when it operates in the phase of 0, 蟺. In addition, the asymmetric spectrum can be driven by the antenna in the phase of 0, 蟺 / 2, which is beneficial to the research of current drive. In the future, ion cyclotron current drive will be an important means of driving core current in ITER device. Therefore, the phase measurement and accurate control of ion cyclotron antenna is of great significance for ion cyclotron heating and driving research. If the phase of the antenna can not be accurately measured and controlled, it may lead to the imbalance of the power between the current bands of the antenna and affect the heating effect. During the EAST discharge experiment, the impedance of the plasma changes with time, which results in the fluctuation of RF implantation power in the ion cyclotron resonance heating system. Prior to this study, the output power of the transmitter was mainly adjusted by manually changing the output amplitude of the signal source, although the amplitude of the signal source remained unchanged within the first gun of the plasma discharge. However, the output power of the transmitter fluctuates greatly, so it is impossible to control the output power accurately. The main content of this thesis is to measure the phase and power of RF wave in ICRH system and to control the closed loop feedback. In this paper, several different phase and power measurement methods are compared. A phase detector based on HMC439 chip is designed on the basis of existing AD8302 phase discriminator, which has wide measurement range (720 掳) and low phase noise. In addition, good linearity also brings convenience to the subsequent data processing. The phase and power measurement and control system is based on FPGA main controller, which is composed of signal acquisition card and feedback control board. The signal acquisition board is mainly responsible for the phase and power input signal conditioning and analog-to-digital conversion. Finally, the data fitting calculation is completed in FPGA. The function of the feedback control board is to realize the real-time feedback control of the phase and power and to communicate with the host computer. We use Labview software to develop upper computer program, and the communication between host computer and control box is realized by USB protocol. Through the design of hardware and software and the continuous optimization of feedback algorithm, the phase and power feedback control system is tested under the false load and plasma discharge environment, respectively. It has been successfully applied to the EAST experiment in 2016. In the case of load impedance variation, the phase and power are automatically stabilized in the target value set by the host computer according to the closed-loop feedback algorithm, which lays a foundation for the development of power and phase modulation experiments.
【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】：TL631.24

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