红外热成像无损检测系统锁相热激励源的研制

Study and Development of Lock-in Thermal Excitation Source for Infrared Thermography Nondestructive Testing System

近年来,我国航空航天、车辆工程及船舶制造业发展迅速,对产品加工工艺及性能指标的要求不断提高。无损检测(NDT)技术也因此越来越受到重视。其中,红外热成像(IRT)无损检测技术作为潜力巨大的无损检测与评估技术,正受到广泛关注。传统的锁相热激励源(ES)由于输出功率低、锁相频率不可调,导致红外热像仪采集不清晰、图像分析效果不理想,很多产品已不能满足后级系统对光照强度的要求。通过对光锁相热成像(LIT)需求的分析,从电力电子的角度入手,采用功率器件搭建创新型拓扑,设计了一种最大输出交流电压250 V、电流10 A的新型大功率红外热成像(ITI)检测热激励源。详细叙述了该锁相热成像激励源的构成、参数计算及工作过程、原理,并通过试验对其进行了测试和验证。将该大功率激励源应用于红外热成像无损检测领域,降低了后级系统对时序热波信号进行数据采集的难度,有利于对缺陷进行更精确的分析。后期将实现系统多级并联,使其输出更高功率,满足红外热成像无损检测系统对更大功率激励源的需求。

In recent years,with the rapid development of aerospace,vehicle engineering and shipbuilding industry in China,the manufacturing process and performance requirements of the products have been continuously improved.Non-destructive testing （NDT） technology is gaining more and more attention.As a potential NDT and evaluation technology,the infrared thermography （IRT） is being widely concerned.The traditional lock-in IRT excitation source （ES） cannot meet the light intensity requirements of the post-stage system because of the low output power and the not adjustable phase-lock frequency,thus the infrared thermography is not clear enough,and the results of image analysis are not ideal.Many products can not meet the requirement of the light intensity for the poststage system.Through analyzing the demands for lock-in thermography （LIT）,and based on electricity and electronics,by adopting power components,a new type of ES of infrared thermal imaging （ITI） detection is designed with a maximum output AC voltage of 250 V and current of 10 A.The structure,parameter calculation,working process,and principle of the LIT ES in the ITI NDT system are described in detail.Experiment has been carried out to test and validate.The high power ES is applied to the field of IRT NDT,it reduces the difficulty of data collection of the sequential heat wave signal in the post-stage system,which helps to analyze the defects more accurately.The next step is to achieve the multi-level parallel system with higher output power.