The cooling performance of the machine with the closed liquid cooling system is excellent. However, the electromagnetic characteristics of the oil separator which sealing the cooling oil in the stator side can have a significant impact on the performance of the machine. In this paper, a liquid cooling structure with the magnetic oil separator is proposed. Taking the 20 000 rpm high‐speed permanent magnet generator as an example, the influence of the electromagnetic parameters of the magnetic oil separator on the generator output performance is studied by the analytical calculation and the finite element method, and the mechanism of the nonlinear variation of the generator output performance with the permeability of the oil separator is obtained. The influence of the oil separator on the air‐gap magnetic field and electromagnetic force is analyzed, and the reduction mechanism of the different permeability of the oil separator on the harmonic magnetic field and radial force is revealed. The vibration acceleration response of the generator stator is obtained through the modal and harmonic response analysis, it is confirmed that the magnetic oil separator has the effect of reducing vibration. In addition, the 3‐D temperature field calculation model of the generator is established, the influence of the thermal parameters of the oil separator on the internal heat exchange of the generator is studied, and the temperature distribution is obtained. Finally, experiments on the electromagnetic performance and temperature rise of the prototype are carried out to verify the correctness of the theoretical analysis. © 2023 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.
The toroidal windings can shorten the axial length of the machine, so it is widely used in high-speed permanent magnet machine. However, under high-frequency operation, the magnetic flux leakage generated by the toroidal windings can cause a lot of eddy current loss on the shell, which will negatively influence the heat dissipation of the machine, resulting to overheating and the machine being unable to function. In this paper, the 40kW,20000rpm high-speed permanent magnet generator (HSPMG) with the toroidal windings is taken as an example to analysis the shell eddy current loss. Based on Laplace and Poisson equations, a quickly analytical calculation model of the shell eddy current loss is established, the influencing factors of the shell eddy current loss are elucidated. By using the finite element method (FEM), the influence of the shell structure and the shell material on the shell eddy current loss is studied, the mechanism of nonlinear variation of eddy current loss is revealed. In addition, the influence of load on the eddy current loss is studied. Furthermore, the 3-D temperature field calculation model of the generator is established, the influence of the shell eddy current loss on the generator temperature is studied, and the temperature distribution is obtained. Finally, the electromagnetic test and temperature rise experiment of the generator are carried out, while the experimental and finite element results are compared to verify the correctness of the model. INDEX TERMSHigh-speed permanent magnet generator, analytical calculation, eddy current loss, 3-D temperature field, optimization design. I. INTRODUCTION 18In recent years, high-speed permanent magnet generator 19 (HSPMG) has been widely used in gas turbines, distributed 20 power generations and flywheels, because of its advantages 21 of high efficiency, high power density and dynamic response 22 capability [1], [2], [3]. The toroidal windings can shorten 23 the axial length of the HSPMG, so the toroidal windings are 24 93 sleeve loss. In addition, comparing the results of FEM and 219 the analytical method, both results are in good agreement. 220 The variation of the shell eddy current loss with the dis-221 tance (d) between the shell and the back windings is shown 222 in Fig. 6. When the distance increases from 0mm to 11mm, 223 the magnetic resistance of the yoke air region is increased. 224 The influence of the magnetic flux leakage on the shell loss is 225 reduced, so the shell eddy current loss decreases from 82.6W 226 to 66.4W. 227 According to the formula (22), the eddy current loss is also 228 affected by the shell thickness. As can be seen from Fig. 7, 229 when the shell thickness is increased from 1mm to 3mm, the 230 shell eddy current loss drops dramatically from 263.9W to 231 89.8W. When the shell thickness is increased from 3mm to 232 10mm, the loss first decreases and then increases slightly with 233 a minimum of 55.9W at 7mm. 234 By using the FEM, the influence of the value and dis-235 tribution of current density on the shell eddy ...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.