Thermal Insulated Leakage Current Measurement using a Fluxgate Sensor with an Aerogel Insulation for DC Charging Applications

The fluxgate current sensor exhibits temperature drift due to its thermal sensitivity, which could affect the accuracy of leakage current measurement; especially, when using for the large variation of temperature and heat in DC charging applications. This paper proposes an improved thermal insulated fluxgate current sensor by using an additional aerogel insulation sheet wrapped around for the sensor. The proposed sensor model was formulated based on the Jiles-Atherton B-H hysteresis model and was solved with the fourth order Lunger Kuta method. The mathematical model was optimized to account for the effect of temperature. Detailed analysis of the temperature drift of conventional fluxgate sensor compared to the proposed one with an aerogel thermal insulation sheet with respect to enhance sensor performance in DC charging pile conditions was presented. The simulation results indicated that the proposed thermal insulation fluxgate current sensor effectively suppressed the temperature drift and thus could achieve safer and more reliable operation of the DC charging pile and offers compared to the conventional sensor.