Research on Characteristics of Magnetohydrodynamic Micro-Angle Vibration Sensor in AC Magnetic Field

Magnetohydrodynamic micro-angle vibration sensor (MHD sensor) is based on the law of electromagnetic induction. The ac magnetic field might be coupled to the working magnetic circuit, thus affecting the sensor output. In order to suppress the influence of ac magnetic on the sensor, a model quantifying the interference between the sensors’ output and ac magnetic field is established. The electrical loop within the MHD sensor is optimized, and magnetic shielding measures are adopted to reduce the external magnetic influence on the sensor. ANSYS Maxwell software is used to simulate and analyze the MHD sensor in the ac magnetic field. Finally, experiments are conducted to verify the proposed model and optimization measures. Electromagnetic coils are used to generate the ac magnetic field needed for the experiments. Simulation and experimental results show that the ac magnetic influences on the static and dynamic characteristics of MHD sensors are different. Specifically, the optimized and shielded MHD sensor is proven to be more insensitive to the ac magnetic, which is followed by the optimized one and shielded one, and the original sensor is the worst. The results demonstrate that the MHD sensor can be improved to be insensitive to the ac magnetic field through electrical loop optimization and the implementation of magnetic shielding measures.