VP16-13 Dynamic Magnetization Measurement System for Soft Magnetic Materials
Creators: Yu-Cheng Chang
Van-Dong Doan
Long-Vu Bui
Truong-Han Nguyen
and Jen-Tzong Jeng
Publisher: name: IEEE
Year: 2025

Evaluating the dynamic magnetization characteristics of the soft magnetic materials is essential for modeling the output response of a fluxgate sensor for which the demagnetizing effect of the core is generally non-negligible [1]. In this work, the dynamic magnetization measurement system for characterizing the soft magnetic core materials of a fluxgate sensor is investigated. The alternating magnetizing field is generated by a solenoid with an inductance of 27.5 mH. The pickup coil, which consists of inversely cascaded sensing and reference solenoids, is mounted inside the magnetizing coil. The reduction in field strength caused by the inductive reactance is overcome by cascading a proper metal film capacitor to the magnetizing coil to form a tank circuit. The distortion of the voltage waveform detected by the pickup coil is minimized by tuning the parameters of the integrator circuit, which converts the voltage waveform into the magnetization signal of the test sample inserted into the sensing coil. It is found that the magnetizing curve of a short ferrite rod shows the frequency-independent magnetizing curve with negligible hysteresis, which can be chosen as the standard sample for calibrating the conversion factor of magnetization measurement. The built system is capable of characterizing the dynamic magnetization cycle of the amorphous soft magnetic materials for use in fluxgate sensors, as shown in Fig. 1. Experimental results show that the material with higher demagnetizing effect exhibits a more consistent susceptibility and saturation field under various amplitudes of magnetizing field up to kilohertz frequencies. The proposed system is valuable for exploring the dynamic magnetic properties of miscellaneous soft magnetic materials to construct the numerical model.References: [1] F.Primdahl et. al, “The fluxgate ring-core internal field,” Measurement Science and Technology, Vol. 13, p. 1248 (2002)
Evaluating the dynamic magnetization characteristics of the soft magnetic materials is essential for modeling the output response of a fluxgate sensor for which the demagnetizing effect of the core is generally non-negligible [1]. In this work, the dynamic magnetization measurement system for characterizing the soft magnetic core materials of a fluxgate sensor is investigated. The alternating magnetizing field is generated by a solenoid with an inductance of 27.5 mH. The pickup coil, which consists of inversely cascaded sensing and reference solenoids, is mounted inside the magnetizing coil. The reduction in field strength caused by the inductive reactance is overcome by cascading a proper metal film capacitor to the magnetizing coil to form a tank circuit. The distortion of the voltage waveform detected by the pickup coil is minimized by tuning the parameters of the integrator circuit, which converts the voltage waveform into the magnetization signal of the test sample inserted into the sensing coil. It is found that the magnetizing curve of a short ferrite rod shows the frequency-independent magnetizing curve with negligible hysteresis, which can be chosen as the standard sample for calibrating the conversion factor of magnetization measurement. The built system is capable of characterizing the dynamic magnetization cycle of the amorphous soft magnetic materials for use in fluxgate sensors, as shown in Fig. 1. Experimental results show that the material with higher demagnetizing effect exhibits a more consistent susceptibility and saturation field under various amplitudes of magnetizing field up to kilohertz frequencies. The proposed system is valuable for exploring the dynamic magnetic properties of miscellaneous soft magnetic materials to construct the numerical model.References: [1] F.Primdahl et. al, “The fluxgate ring-core internal field,” Measurement Science and Technology, Vol. 13, p. 1248 (2002)