Digital LLRF controller for SSRF booster RF system upgrade  

作　　者：张志刚 赵玉彬 徐凯 郑湘 李正 赵申杰 常强 侯洪涛 马震宇 罗琛 毛冬青 是晶 王岩 刘建飞 

机构地区：[1]Shanghai Institute of Applied Physics, Chinese Academy of Sciences [2]University of Chinese Academy of Sciences [3]Shanghai Key Laboratory of Cryogenics & Superconducting RF Technology

出　　处：《Nuclear Science and Techniques》2015年第3期26-32,共7页核技术（英文）

基　　金：Supported by the National Natural Science Foundation of China(No.11335014)

摘　　要：The low level radio frequency(LLRF) system for booster accelerator at Shanghai Synchrotron Radiation Facility(SSRF) was upgraded by a digital controller based on field programmable gate array(FPGA) technology.Parameters of voltage, frequency and field flatness in the two 5-cell cavities are controlled to meet the requirements of booster. In this article, the ramping curve of cavity voltage, amplitude and phase control loop with vector sum of the two 5-cell cavities, tuning loop and field flatness loop are analyzed and discussed in detail.A different method in tuning loop is adopted due to the limitations of ADC channels. The function realizes energy ramping of electron beam from 150 Me V to 3.5 Ge V with a repetition rate of 2 Hz. With the new LLRF controller, the phase stability at ramping mode in 10 hours long operation is improved from ±1.5°(RMS) with open loop to ±0.15°(RMS) with close loop, while the detuning phase and field flatness are maintained to within ±2°and ±1%, respectively.The low level radio frequency（LLRF） system for booster accelerator at Shanghai Synchrotron Radiation Facility（SSRF） was upgraded by a digital controller based on field programmable gate array（FPGA） technology.Parameters of voltage, frequency and field flatness in the two 5-cell cavities are controlled to meet the requirements of booster. In this article, the ramping curve of cavity voltage, amplitude and phase control loop with vector sum of the two 5-cell cavities, tuning loop and field flatness loop are analyzed and discussed in detail.A different method in tuning loop is adopted due to the limitations of ADC channels. The function realizes energy ramping of electron beam from 150 Me V to 3.5 Ge V with a repetition rate of 2 Hz. With the new LLRF controller, the phase stability at ramping mode in 10 hours long operation is improved from ±1.5°（RMS） with open loop to ±0.15°（RMS） with close loop, while the detuning phase and field flatness are maintained to within ±2°and ±1%, respectively.

关 键 词：数字控制器 射频系统 SSRF 低电平 增强器 现场可编程门阵列 上海同步辐射装置 控制回路 

分 类 号：TL53[核科学技术—核技术及应用]