Theoretical Analysis of Triple Liquid Stub Tuner Impedance Matching for ICRH on Tokamaks

The impedance matching is crucial for continuous wave operation of ion cyclotron resonance heating（ICRH） antennae with high power injection into plasmas.A sudden increase in the reflected radio frequency power due to an impedance mismatch of the ICRH system is an issue which must be solved for present-day and future fusion reactors.This paper presents a method for theoretical analysis of ICRH system impedance matching for a triple liquid stub tuner under plasma operational conditions.The relationship of the antenna input impedance with the plasma parameters and operating frequency is first obtained using a global solution.Then,the relations of the plasma parameters and operating frequency with the matching liquid heights are indirectly obtained through numerical simulation according to transmission line theory and matching conditions.The method provides an alternative theoretical method,rather than measurements,to study triple liquid stub tuner impedance matching for ICRH,which may be beneficial for the design of ICRH systems on tokamaks.

Design of a New Type of Stub Tuner in ICRF Experiment

In the Ion Cyclotron Range of Frequency (ICRF) heating experiment, impedance matching is of great practical significance, because wide variations in antenna loading are observed within the discharge, in tokamaks operating in H-mode. A sudden decrease in antenna loading accompanying the L-mode to H-mode transition typically occurs on a timescale of a few milliseconds, as does the increase in loading at the H- to L-mode transition. Therefore, it is necessary to match dynamically in the transmission line between the generator output and the antenna input connections[1]. A new type of stub tuner being developed utilizes the difference in radio-frequency wavelengths between gas and liquid due to different relative dielectric constants. The impedance matching can be adjusted in realtime in an attempt to track the variations in the antenna loading. Since there are no mechanically moving parts in the short ends of stub, the change can be more convenient and safe, moreover, it can withstand higher voltage without breakdown. This system device will be applied in the HT-7 superconductor Tokamak ICRF experiment.

Design and Realization of Liquid Stub Tuner Control System

In microwave circuit and aerial system, impedance matching is very important. Liquid stub tuner is a new type of impedance matching device. In the HT-7 Tokamak Ion Cyclotron Resonance Heating ( ICRH ) system, we have already adopted liquid stub tuner to replace the conventional stub tuner. It is urgent to develop a control system of the liquid stub tuner. This paper mainly introduces the design and realization of the liquid stub tuner control system , and briefly introduces its three controlling functions: local control, remote control and computer control.

EAST装置离子回旋加热液态阻抗匹配系统的研究

介绍了EAST装置离子回旋加热系统中的两种实现阻抗匹配的方式,用三支节液态调配器取代传统的滑竿式三支节调配器和用液态相移器与单支节液态调配器相结合组成液态阻抗匹配系统。通过对液态阻抗匹配系统的分析,表明这两种方式都能够较好地实现阻抗匹配。

基于EAST装置上液态调配器系统的研究

液态调配器是用于离子回旋共振加热系统以代替传统活塞式调配器的一种新型阻抗匹配装置。通过对液态调配器工作原理的研究,设计了液态调配器的油路系统,采用计算机和可编程控制器对系统进行控制。同时,对液态调配器各支节匹配高度的计算方法进行了研究,提出了计算公式,并利用实验中测得的数据对计算公式进行了验证。经过两轮EAST实验使用证实,该系统完全满足设计要求。

三销钉调配器的研究

三销钉调配器是一种常用的阻抗调配器,其销钉深度、间距以及销钉的半径均可根据需要进行设置,是大功率微波系统中实现阻抗匹配的常用器件。本文介绍了一种新的分析方法,将每个销钉看作为一个独立的二端口网络,三销钉调配器就相当于三个二端口网络的级联器件,利用其级联规律,可以为三销钉调配器的自动控制提供一种便捷的方法。

大功率微波智能阻抗调配技术研究

传统微波阻抗匹配技术很难对动态负载做到实时、快速、稳定的匹配。针对这一问题,本文构建了一个能够为动态负载提供实时快速匹配的智能阻抗调配系统。该系统将三探针检测技术与三销钉调配器进行集成,利用三探针检测器实时检测动态负载反射系数的变化,同时将检测到的反射系数传输到微处理器,由微处理器进行处理,控制步进电机调节三销钉调配器,将反射系数稳定在工程理想值范围内,从而实现微波系统动态负载的阻抗匹配。

液态调配器控制系统

在微波电路和天线系统中,阻抗匹配是十分重要的问题。液态调配器是一种新型的阻抗调配装置,在HT-7托卡马克等离子体大功率射频波的离子回旋共振加热系统中,已采用液态调配器来取代传统的支节调配器。主要讨论了液态调配器控制系统的设计与实现,介绍了液态调配器控制系统的3种功能:本地控制、远程控制、计算机控制。