Design of dual-range TMR current sensor with SOG-MR structure for enhanced anti-interference performance
Abstract
The demand for high-performance current sensors in the growing new energy areas has driven the need for improved sensitivity, resolution, and wide range. External interference, however, remains a significant challenge that limits sensor accuracy. To address this, this paper presents a novel dual-range TMR current sensor featuring a semi-open gap magnetic ring (SOG-MR) structure, specifically designed to mitigate the impact of external interference signals and enhance detection accuracy. Using Ansys Maxwell simulations, we optimized the SOG-MR design by leveraging two key effects: the magnetic aggregation effect to enhance sensitivity at small currents, and the magnetic shunt effect to extend the measurement range for large currents. In contrast to conventional fully open gap MR (FOG-MR) structures, the SOG-MR design offers greater flexibility in tailoring structural parameters, W_r and L_g, enabling the simultaneous enhancement of both the magnetic aggregation effect and the magnetic shunt effect. More importantly, the SOG-MR structure exhibits excellent anti-interference capability, reducing external interference signals by 3-5 orders of magnitude along the X axis. Anti-interference tests demonstrate the TMR current sensor based on this design achieves a remarkable 182-fold improvement in shielding effectiveness, compared to the FOG-MR structure, with further suppression as interference intensity increases. Experimental results indicate that the current sensor shows a high sensitivity of 78.4 mV A^-1 and excellent linearity of 0.09% within a +-10 A range, with a broader detectable range of +-500 A and sensitivity of 3.20 mV A^-1. The sensor operates effectively across a bandwidth from DC to 58 kHz. This innovative SOG-MR based current sensor offers a promising solution for high-precision, interference-resistant current sensors in applications like smart power systems and new energy vehicles.
Yazhou Dong
Research Assistant @ CUT
