压电变压器结构的便携式磁电耦合交/直流磁强计

To address the heat accumulation issue in magneto-mechano-electric coupling effect sensors and the corresponding challenges in low-power applications and device durability, this paper proposes a magnetometer which is based on a magnetoelectric coupling piezoelectric transformer structure. The sensor integrates piezoelectric and magnetostrictive materials and utilizes a dual-mode detection mechanism. In passive mode, the MME coupling effect directly detects AC magnetic fields, while in active mode, DC magnetic field detection is achieved via a voltage-driven Delta-E effect. Experimental tests and equivalent circuit simulations were conducted to investigate the resonant peak shift characteristics of the longitudinal vibration mode and the magnetic field response relationship between the elastic compliance coefficient and the mechanical quality factor. A low-noise charge amplifier circuit was designed to efficiently convert the high-impedance charge signal generated by the magnetoelectric sensor into a low-impedance voltage signal. Based on these findings, a portable AC/DC magnetometer prototype was developed, integrating an STM32 microcontroller and the driving circuit. Experimental results showed that the detection limits for AC magnetic fields at 100 Hz and 300 Hz were 3. 18 A/m and 0. 88 A/m, respectively, while the DC magnetic field detection limit was 3. 58 A/m. The performance of this magnetometer has significantly outperformed commercial Gauss meters based on the Hall effect (with a detection limit of approximately 55. 7 A/m). Therefore, this magnetometer has substantially improved magnetic field detection sensitivity and resolution, particularly for weak magnetic field detection applications.