A Stacked Tunneling Magnetoresistance Sensor Structure for Improved Multi-Phase Current Measurement

Magnetoresistive materials are gaining popularity in current and position-sensing applications due to their high magnetic sensitivity and stable performance over varying ambient environments. Among these materials, tunneling magnetoresistance (TMR) technologies distinguish themselves by reduced power consumption and compact packaging. However, as the magnetic field remains the primary sensing target, additional magnetic shielding or cores are often necessary in high-current, multi-phase scenarios or intricate magnetic environments. As for machine drives, a clean interface between the testing object and the sensor is even more difficult to ensure due to the mechanical disturbance and electromagnetic interface. In this work, the working principle and current measurement performance of a commercially available TMR sensor module is presented. A novel stacking structure that capitalizes on orthogonal regions generated by interactive cross-phase fields is proposed, mitigating the need for supplementary magnetic shielding between phases. Simulation and experimental results are carried out to support the efficacy of the proposed stacking structure.