A Vectorial Current Density Imaging Method Based on Magnetic Gradient Tensor

• Published in: Sensors (Basel, Switzerland) Vol. 23; no. 13; p. 5859
• Main Authors: Wu, Yangjing, Zhang, Mingji, Peng, Chengyuan, Zhang, Zehuang, He, Yichen, Zhang, Wenwei, Chang, Liang
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 24.06.2023; MDPI
• Subjects: closed-form inversion; Communication; current density inversion; Datasets; Fourier Analysis; Integrated circuits; Lithium; magnetic current imaging; Magnetic Fields; magnetic gradient tensor; Magnetic Resonance Imaging - methods; Magnetics; Noise; nondestructive testing; Phantoms, Imaging; Power; Sensors; China; Beijing China; magnetic gradient tensor; current density inversion; nondestructive testing; magnetic current imaging; closed-form inversion
• ISSN: 1424-8220; 1424-8220
• DOI: 10.3390/s23135859

Magnetic current imaging is deemed an emerging powerful technique for visualizing electrical currents in electronic devices. However, the existing magnetic-field-based Fourier Transform back-evolution method is limited by its mono-function of imaging the magnitude of current density in devices under test, and subject to background noise distortion. Here, we developed a novel vectorial current density imaging method based on the detection of the magnetic field gradient generated by current carrying conductors. A closed form solution of current density inversion was analytically derived and numerically verified. Experiments were conducted by scanning tri-axial fluxgate sensor over different shapes of electrical wires. The results show that a current density resolution of 24.15 mA/mm2, probe-to-sample separation of 2 mm, and spatial resolution of 0.69 mm were achieved over a maximum scanning area of 300 mm × 300 mm. Such a method is verified to be capable of simultaneously imaging both magnitude and directions of current density, which is a promising technique for in situ noninvasive inspection for the power electronic and semiconductor industry.