基于多参数估计的矢量调制器矫正技术研究及验证  

Design and test of multi-variable estimation-based calibration for vector modulator

作　　者：徐一茗 肖诚成 方文程 XU Yiming;XIAO Chengcheng;FANG Wencheng(Shanghai Advanced Research Institute,Chinese Academy of Sciences,Shanghai 201204,China)

机构地区：[1]中国科学院上海高等研究院,上海201204

出　　处：《核技术》2024年第11期33-40,共8页Nuclear Techniques

基　　金：国家自然科学基金(No.12105345)资助。

摘　　要：上海软X射线自由电子激光(Shanghai Soft X-ray Free-electron Laser,SXFEL)在搜寻最大加速相位的过程中微波低电平(Low Level Radio Frequency,LLRF)系统的射频输出幅度会产生振荡,进而影响整个装置的稳定性。针对此问题,本文开发了基于多参数估计的矢量调制器(Vector Modulator,VM)矫正技术,用于稳定微波功率源的输出幅度,并且在闭环控制中降低幅、相两个环路的串扰。该方法首先分析并建立了VM的非理想模型,通过系统真实的输入输出估计模型中的多个参数,设计了矫正算法以补偿非理想因素对系统造成的影响,使VM输出的激励信号不仅具有更好的幅相隔离度,而且可同时消除输出波形与回测波形之间的相位差。实验结果表明:经该方法矫正后,相位设定值的改变对VM输出幅度的影响由4.0%(Root Mean Square,RMS)下降到0.19%(RMS),同时相位的设定值与回测值的偏差控制在0.18°(RMS)以内。[Background]The RF output amplitude of the Low Level Radio Frequency(LLRF)system in Shanghai Soft X-ray Free-electron Laser(SXFEL)exhibits oscillations during the search for the maximum accelerating phase,compromisingthe stability of the entire device.[Purpose]This study aims to develope a multi-variable estimationbased calibration technology for the Vector Modulator(VM)to stabilize the RF output amplitude and reduce the crosstalk between the amplitude and phase loops in closed-loop control.[Methods]A non-ideal model of the VM was analyzed and established to address output amplitude stabilization in the LLRF system's microwave power source.The parameters of this model were estimated using real input and output data from the VM.A calibration algorithm was then designed and implemented to mitigate the adverse effects caused by non-ideal factors.[Results]Experimental results demonstrate that the proposed method reduces the impact of phase setpoint changes on the VM's output amplitude from 4.0%Root Mean Square(RMS)to 0.19%RMS after calibration.Furthermore,the error between the phase setpoint and measured phase was reduced to within 0.18°RMS.[Conclusions]This proposed method improvesisolation between amplitude and phase,effectively eliminating phase differences between the output and sampled waveforms.

关 键 词：低电平控制系统 矢量调制器 多参数估计 误差矫正 

分 类 号：TL503.2[核科学技术—核技术及应用]