上海光源超导三次谐波腔低电平研制  

Low level radio frequency controller for superconducting third harmonic cavity at SSRF

作　　者：张志刚 赵玉彬 徐凯 郑湘 常强 赵申杰 马震宇 蒋鸿儒 杨文峰 黄雪芳 王岩 是晶 侯洪涛 ZHANG Zhigang;ZHAO Yubin;XU Kai;ZHENG Xiang;CHANG Qiang;ZHAO Shenjie;MA Zhenyu;JIANG Hongru;YANG Wenfeng;HUANG Xuefang;WANG Yan;SHI Jing;HOU Hongtao(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》2022年第12期1-8,共8页Nuclear Techniques

摘　　要：上海光源自主研制的被动式超导三次谐波腔已通过束流测试,在正常运行时需要对感应腔压进行精确控制,以实现束团拉伸和提高束流寿命的目标。根据这一特定需求研制了一套数字化低电平控制系统,此系统基于现场可编程门阵列(Field-Programmable GateArray,FPGA)板卡和上下变频板卡,采用I/Q(In-phase/Quadrature)解调技术,设计了慢速步进电机和快速压电陶瓷驱动协同控制算法以及被动超导腔失超探测算法,用于实现腔压幅值稳定度控制及三次谐波腔运行状态监测等功能。在加速器工作在超过120 mA的top-up模式下,三次谐波腔感应腔压幅值的稳定度由开环的±5%提高到闭环的±1%以内,满足设计指标;压电陶瓷驱动电压波动在120 V范围内变化,达到输出电压平滑稳定的效果,束流寿命提高超过一倍。[Background]The superconducting third harmonic cavity has been developed independently in Shanghai Synchrotron Radiation Facility(SSRF)and passed beam tests.The cavity electric field needs to be precisely controlled during operation to achieve the goal of stretching beam cluster and improving beam life.[Purpose]This study aims to design a digital low level radio frequency(DLLRF)controller for superconducting third harmonic cavity at SSRF.[Methods]The hardware of controller was based on a field-programmable gate array(FPGA)board and a front-end board whilst in-phase/quadrature(I/Q)demodulation techniques were implemented in the software of controller.A synergistic strategy was adopted for driving the stepper motor with slow tuning speed and piezoelectric ceramic with fast tuning speed,and an algorithm for the quench detection for passive cavity.Finally,experimental tests were performed to verify the effectiveness of this designed DLLRF.[Results]When the state is in top-up mode over 120 mA,the amplitude stability has improved form±5%with open loop to less than±1%with close loop,the voltage of piezo has varies smoothly and stably within 120 V,and the beam life has improved more than doubled.[Conclusion]A digital low level radio frequency controller for the superconducting third harmonic cavity has been designed and satisfies the requirements for SSRF.

关 键 词：数字化低电平 三次谐波腔 腔压控制 腔压稳定度 

分 类 号：TL506[核科学技术—核技术及应用]