The relative permeability, coercivity, and remanence of permalloy are closely related to the performance of magnetic shielding devices. In this paper, the relationship between the magnetic properties of permalloy and the working temperature of magnetic shielding devices is measured. Firstly, the measurement method of permalloy properties based on the simulated impact method is analyzed. What is more, a magnetic property test system consisting of a soft magnetic material tester and a high–low temperature chamber for permalloy ring samples at different temperatures was established to measure DC and AC (0.01 Hz to 1 kHz) magnetic properties at different temperatures (−60 °C to 140 °C). Finally, the results show that compared with room temperature (25 °C), the initial permeability (μi) decreases by 69.64% at −60 °C and increases by 38.23% at 140 °C, and the coercivity (hc) decreases by 34.81% at −60 °C and increases by 8.93% at 140 °C, which are the key parameters in the magnetic shielding device. It can be concluded that the relative permeability and remanence of permalloy are positively correlated with temperature, while the saturation magnetic flux density and coercivity are negatively correlated with temperature. This paper is of great significance to the magnetic analysis and design of magnetic shielding devices.

The magnetic shielding devices works at different temperatures due to the influence of gas chamber and environmental temperature in the application of ultra-highly sensitive spin exchange relaxation free (SERF) magnetometer. To accurately evaluate the residual magnetic field of magnetic shielding device at different temperatures, it is necessary to build the magnetization model considering temperature. However, the modelling of permalloy’s magnetization properties and the measurement of residual magnetic field in magnetic shielding devices at different temperatures haven’t been considered. In this paper, the optimized Jiles-Atherton model of permalloy considering temperature is constructed in which parameters are extracted by particle swarm optimization algorithm. To further verify the effectiveness of the model in the magnetic shielding device, it is applied to the residual magnetic field simulation of magnetic shielding devices and verified by measurement. The optimized Jiles-Atherton model considering temperature improves the calculation accuracy of magnetic shielding devices, which is of great significance for the application of ultra-highly sensitive SERF magnetometers.

Hollow-cup motors are usually used in spacecraft because of their low power consumption and high control accuracy. However, because the air-gap between the permanent magnets (PMs) and the rotor of the hollow-cup motor is uniform, the sinusoidal characteristic of the air-gap magnetic field waveform is inferior and the total harmonic distortion (THD) is large, resulting in torque ripple. For the large air-gap hollow-cup motor, the existing methods for optimizing the sinusoidal characteristics of the air gap magnetic field change the shape of PMs, but the changed PMs are difficult to manufacture and magnetize, resulting in the methods being limited and not being able to achieve the ideal optimization effect for the hollow-cup motor. Based on the characteristics of the inner rotor and outer rotor rotating synchronously during operation, a new structure design of the hollow-cup motor with an eccentric inner rotor is proposed instead of changing the PMs’ shape. Firstly, the mathematical model of the hollow-cup motor is established. Then, the FEM shows that the inner rotor’s eccentricity can bring the air-gap magnetic field waveform closer to the ideal sinusoidal waveform and can effectively reduce the THD. Finally, a prototype with the optimal eccentricity value is made for experimental verification.

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