Design and development of a current sensor with temperature stability and high resolution

Abstract

This paper presents a current sensor for measurement of AC and DC. The sensor consists of two toroidal magnetic cores. One core works in fluxgate principle for the measurement of DC and low frequency AC. Another additional toroidal core is used as a current transformer for higher frequency application. Bidirectionally saturated fluxgate principle is used in this sensor to achieve better temperature characteristic for high current measurement. Moreover, an improved bidirectionally saturated fluxgate principle is proposed to measure small current, which improves the resolution of the sensor. A prototype is designed and the tested results show that the sensor can measure currents up to 150 A, with an accuracy of 5%o, and a bandwidth of 60 kHz.