Design of a pulsed eddy current testing power supply combining constant amplitude and clamp voltage control

Abstract

Pulsed Eddy Current Testing (PECT) is a hotspot for non-destructive testing of metallic materials. As a key part of the system, the performance of the excitation source will directly affect the results. A new pulse power supply circuit is proposed to overcome the problems of long turn-off time, no constant current control, large volume, and low power of the excitation source in the existing PECT method for material defects. It uses a combination of linear regulated power supply and switched power supply to realize a compound circuit topology of constant current and constant voltage clamp. Then, the stability and rapidity of the excitation system are verified through simulation experiments and prototype demonstration. The amplitude of the pulsed power supply is adjustable within 20A, with an inaccuracy under 1%, and it is able to turn off at high speed with an edge fall time of nanoseconds. Finally, the prototype is used to simulate the detection of aluminum metal defects, the peak voltage of the detection coil can accurately identify different defect depths with high resolution. Its results show that the design method is feasible and has excellent performance.