Improved Thermal Management and Analysis of Stator-PM Counter-Rotating Dual-Rotor High-Speed Electrical Machine for FESS

In this article, a thermal network model considering winding layered (TNM-WL) is developed to conduct the thermal analysis and an integrated structure with magnetic isolation and cooling functions (IS-MIC) is proposed to improve the heat dissipation capacity with maintaining magnetic isolation effect for a stator permanent magnet counter-rotating dual-rotor high-speed flywheel electrical machine (SPMCRDR-HSEM) under high-vacuum operation condition. First, the topology of the SPMCRDR-HSEM is introduced and the corresponding TNM-WL is developed to calculate machine temperature rise. Then, the circumferential permanent magnets (PM) segmentation strategy is investigated for the reduction of PM eddy-current loss, which is the main root cause of machine heating. Furthermore, the IS-MIC is proposed, and the inlet flow rate of the fluid is designed by theoretical and computational fluid dynamics methods. Finally, the prototype of the SPMCRDR-HSEM with IS-MIC is manufactured and the experimental tests are carried out to verify the effectiveness of the IS-MIC. The experimental test results reveal that the IS-MIC exhibits a prominent cooling effect, which provides a new method for solving the thermal management problems of this kinds of machine.