A Nondestructive Method to Evaluate of DC-DC Converters Using Subsurface Magnetic Field Imaging with Pulse Width Modulation

Abstract

This study proposes a nondestructive method to evaluate switching power supply circuits using subsurface magnetic field imaging with pulse-width modulation. DC-DC converters are widely used to transform the voltage of lithium-ion batteries and other devices in many applications such as electric vehicles, telecommunications, medicine, uninterruptible power supplies, and various consumer products. However, relatively few methods are available to assess their reliability. Although a nondestructive evaluation method using subsurface magnetic field imaging with electromagnetic field reconstruction was proposed to address this problem in a previous work, the upper limit of the response frequency of this method was dependent on the magnetic sensor. In this study, a pulse-width modulation method was incorporated into the circuit to measure the magnetic field distribution of a DC-DC converter operating above the response frequency of magnetic sensors. We report an evaluation of the operation of a DC-DC converter in terms of the measured magnetic field distribution.