1. China Jiliang University, Hangzhou, Zhejiang 310018, China
2. National Institute of Metrology,The Key Laboratory for the Electrical Quantum Standard, Beijing 100029, China
3. Department of Electrical Engineering, Tsinghua University, Beijing 100084, China
Abstract：The temperature field of permanent-magnet system is analyzed based on COMSOL finite element simulation.Through the thermal analysis of permanent-magnet system, the temperature rise curves of permanent-magnet in different working modes are obtained. It is found that the permanent-magnet-disk has a temperature difference of 10-4 between the two working modes. Because of the temperature coefficient of -3×10-4 K-1 for samarium cobalt permanent magnet disk,the impact on the measurement of flux difference in 10-8 orders of magnitude. Three schemes are proposed to solve the coil heating problem, reduce the interference of the temperature to the the measurement of Planck constant. The three options are to adjust the induction coil current, increase the radiation coefficient and change the balance support structure.
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2019, Vol. 40 
