摘要
激励电源性能直接影响脉冲涡流热成像的信号特性提取、检测灵敏度和缺陷检出率,针对常规水冷铜管式感应加热电源存在电磁耦合效率低、加热均匀性差等问题,提出了一种含U型磁轭探头的新型脉冲激励电源。基于脉冲涡流热成像检测理论和电磁热耦合方程,提出了一种将激励线圈缠绕在U型磁轭上的探头结构,进一步分析了加热时间对试样裂纹区域温度场的影响;给出了脉冲激励电源整体系统方案,通过对电压源型全桥逆变电路换流过程进行分析,为合理设置IGBT开通、关断控制信号提供参考;为实现快速搜索负载谐振频率并实时跟踪谐振频率,提出了一种改进型全数字定角频率跟踪技术,并详细阐述了该技术的实现过程;对研制的脉冲激励电源性能进行测试以验证理论分析的正确性,并将其应用于脉冲涡流热成像金属表面裂纹的检测。
The performance of exciting power supply can directly influence the signal feature extraction,the detection sensitivity and detection probability in pulsed eddy current thermography.Aiming at the problems of the low electromagnetic coupling efficiency and the poor heating uniformity in the traditional water-cooled copper tube induction heating power,a pulsed exciting power supply with a Ushaped yoke probe is proposed.Based on the detection theory of pulsed eddy current thermography and electromagnetic heat coupled equations,a probe structure with excitation coil twining the U-shaped yoke is designed.The effects of coil ampere-turns and heating time on the temperature field distribution of sample crack are analyzed.Then the integrated system scheme of pulsed exciting power system is introduced.The commutation process of the voltage-fed full-bridge inverter is also discussed,which provides a reference for reasonable setting the IGBT control signal to turn on or off.In order to realize quick searching resonance frequency of the load and effective realtime tracking resonant frequency,a modified all digital fixed-angle frequency tracking technology is proposed and realization process is also elaborated in detail.To verify the validity of theoretical analysis,the performance of pulsed exciting power supply is tested and also applied to detect of metal surface crack in pulsed eddy-current thermography.
作者
唐波
方旭
侯德鑫
叶树亮
Tang Bo;Fang Xu;Hou Dexin;Ye Shuliang(Institute of Industry and Trade Measurement Technique, China Jiliang University ,Hangzhou 310018, China)
出处
《仪器仪表学报》
EI
CAS
CSCD
北大核心
2018年第1期208-215,共8页
Chinese Journal of Scientific Instrument
基金
浙江省自然科学青年基金(LQ16F030003)项目资助
关键词
脉冲涡流热成像
激励电源
U型磁轭探头
全桥逆变电路
频率跟踪技术
pulsed eddy current thermography
exciting power supply
U-shaped yoke probe
full-bridge inverter circuit
frequency tracking technology
