Pulsed eddy current testing is the main method of nondestructive testing of metal materials,and the performance of the excitation power supply as a key part of the system will directly affect the test results.In order to solve the problems of long shutdown time,no constant current control and low power of the excitation power supply in the existing ma-terial defect pulse eddy current testing methods,an investigation of defect detection meth-ods for non-magnetic materials was conducted and a new pulse power supply circuit was proposed,which adopted a linear adjustment constant current source to realize the compos-ite circuit topology of constant current and constant voltage clamping.Firstly,the closed-loop analysis of the linear unit is carried out to prove the feasibility of the circuit,and then the stability and rapidity of the pulse power supply are verified by the prototype demonstra-tion.The amplitude of the pulse power supply is adjustable within 20 A,and the amplitude error is less than 1%.It can be shut down at high speed with a drop time in the nanosecond range.Finally,a pulsed eddy current testing system was built using the pulse power supply,and crack defect testing experiments were carried out on aluminum alloys.By extracting the peak voltage,it is found that the system can accurately recognize different defect depths with high resolution.
关键词
缺陷检测/脉冲涡流检测/脉冲电源/恒流源/钳位电路
Key words
defect testing/pulsed eddy current testing/pulsed power supply/constant current source/clamping circuits
维普
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