Design and Development of Intelligent Current Sensor Based on Tunnel Magnetoresistance

Abstract

The discovery of tunnel magnetoresistance (TMR) effect and the development of its devices provide a new technical means for power system current measurement and can greatly reduce the size of the current sensor. This paper designs an intelligent current sensor based on TMR technology. The sensor is composed of energy-absorbing magnetic core, TMR magnetic core and intelligent processing unit. It has the characteristics of self-energy, intelligent processing, high precision, two-way communication, low power consumption and small size. The experimental results show that the nonlinearity of the sensor is 0.12% for the current range from OA to 720 A with the maximum error limited to ±0.5%, the average working power consumption is as low as 19.5$\mu$A, and the sensor can rely on its own power coil that collect the energy of power frequency electromagnetic field to maintain stable operation, which satisfied the needs for deployment and rapid data sharing of sensor in smart grid construction.