Improving Information Collection Environment of Magnetocardiography Device Through Adaptive Interference Suppression Strategy

Multiple frequencies high-amplitude magnetic interference in the environment can adversely affect the detection of cardiac magnetic field signals inside magnetocardiography device. Adaptive multi-resonance control (AMR) is suitable for suppressing such interference, but the stability of active magnetic field compensation system (AMC) will be destroyed by the influence of the time delay of the sensor. To address this problem, this paper proposes a interference suppression method that combines an improved adaptive multi-resonance controller (IAMR) with proportional differential (PD) and linear extended state observer (LESO). Experimental results show that PD-LESO-IAMR can effectively suppress multiple frequencies magnetic interference under the premise of ensuring system stability. Compared with conventional PD-LESO, the average magnetic field interference in the MSC can be reduced from 3.73 pT to 1.80 pT, and the maximum anti-interference ability was increased by 50.25%. Note to Practitioners—The motivation of this paper is to control the magnetic field generated by the coil to reduce the influence of environment magnetic field fluctuations on the measurement of weak magnetic field signals. Existing magnetic field compensation methods mainly focus on the design of coils, and rarely consider optimization and improvements in control methods. Therefore, the suppression effect of magnetic field interference at specific frequencies in the environment is insufficient. This paper proposes an adaptive interference suppression strategy that can effectively suppress high-amplitude magnetic interference without being affected by system time delays. By applying the proposed control strategy, the magnetic field fluctuations are kept within a smaller range, improving the accuracy of magnetic field measurement. Future work is to extend the proposed method to more application scenarios that require extremely weak magnetic field environments. The proposed control strategy is also valuable in solving the high-frequency unbalanced magnetic pull of the magnetic levitation rotor system, improving the high-frequency current suppression of the permanent magnet synchronous motor, and improving the measurement accuracy of the atomic magnetometer for periodic magnetic field signals.