Axial flux motors for aviation systems operate at high altitudes, and the initial operating temperature of the motor is low, but due to the thin air, the motor temperature rise is high and the stator material temperature variation range is large1, especially the segmented stator is close to the motor winding coil, and the thermal stress has a non-negligible effect on its material2. The segmented stator laminated magnetic energy model has been extensively studied in past researches, and no research has been proposed to consider the magnetic energy model of the laminated structure under the thermal stress of the material.
When the temperature changes, the segmented stator is not completely free to expand and contract due to the external constraints and the mutual constraints between the internal parts, thus generating thermal stresses 3. Previous studies have shown that the temperature itself affects the magnetic properties of the material. In this paper, we intend to analyze the magnetic properties of the material by means of a coupled material multiphysics field testbed, and to divide the temperature-induced effects into the effects of temperature on the inherent properties of the material itself and the effects of thermal stresses induced by temperature changes on grain-oriented silicon steel, and to separate them equivalently. In this paper, a comparative analysis of the stator with different thicknesses of grain-oriented silicon steel is carried out, and the deformation of different stator materials under thermal stress is calculated by finite elements. Finally, the thermal stress effect percentage is tested experimentally. It is found that the use of thinner oriented silicon steel material will greatly reduce the effect of thermal stress on its magnetic properties.
1 Paredes J A, Saito C, Abarca M, et al. Study of effects of high-altitude environments on multicopter and fixed-wing UAVs' energy consumption and flight timeC//2017 13th IEEE Conference on Automation Science and Engineering (CASE). IEEE, 2017: 1645-1650.
2 Wu Y, Ming T, Li X, et al. Numerical simulations on the temperature gradient and thermal stress of a thermoelectric power generatorJ. Energy conversion and management, 2014, 88: 915-927.
3 Yong L, Liang W, Qian W, et al. Calculation of deformation and material stress of a rotary voice coil motor used in aerospaceJ. Journal of Computational and Theoretical Nanoscience, 2015, 12(11): 4499-4505.
Fig. 1 Multi-physics field testing of two materials
Fig. 2 Simulation and physical model