中文摘要：

针对涡流热成像中常规单路激励存在对裂纹方向依赖性强和检测灵敏度低等问题,提出一种双路正交激励电源系统,在试样表面感应出旋转涡流场以满足对任意方向裂纹的热激励。首先阐述了涡流热成像检测原理,在此基础上提出双路正交激励电源系统;然后基于旋转磁场理论引入复合式双U型激励探头结构,利用ANSYS软件对其参数进行优化;最后研制了一套以AVR和FPGA来实现数字锁相环的双路激励电源系统,对其性能进行测试并将其应用于不同走向裂纹的热激励实验中,实验结果表明：该电源系统在涡流热成像中可有效降低对裂纹方向的依赖性和提高缺陷裂纹检测灵敏度。

英文摘要：

Aiming at the problems such as strong dependence on crack orientation and the low sensitivity in the conventional single-channel excitation for the eddy current thermography,a double orthogonal excitation power supply system was proposed,which can induce rotating eddy current field in the sample surface to meet the demand of any direction crack thermal excitation.First,the detection principle of eddy current thermography was described.On the basis of this,the double orthogonal excitation power supply system was put forward.Then,the compound double U-shaped exciter probe was introduced based on the rotating magnetic field theory,and its parameters were optimally designed with software ANSYS.Finally,the double orthogonal excitation power supply system with AVR and FPGA to realize digital phase locked loop was developed,and the system performance was tested and the system was applied to the thermal excitation experiments of the different direction crack sample,and the experiment results show that the power system can effectively reduce the dependence of the crack direction and improve the detection sensitivity of the defect crack in the eddy current thermal.