Tunnel magnetoresistive sensor design and applications for current measurement

Abstract

Current sensing plays an important role in electric energy measurement, relay protection, intelligent equipment control and other fields in smart grid. Compared with traditional current transformers, for example, Rogowski coils and Hall current sensors, Tunnel magnetoresistance (TMR) sensor has the advantages of input/output magnetic isolation, AC and DC current measurement ability, wide bandwidth, small size, et al. Accordingly, TMR sensors are applicable for various scenarios and meet multiple current measurement needs. Based on the analysis of the principle of TMR sensor, the structure of current sensor system based on tunnelling magnetoresistance is introduced. Then, the designs of filter circuit and temperature compensation circuit are given. Finally, the experimental results show that TMR current sensor has good performance for current measurement, indicating widely applications in the field of current measurement in the future.