Optimal Design Of Radial Permanent Magnet Bearing For Small And High Speed Centrifugal Fan

In modern society,wind turbines are widely used in industrial production and people's life.For more than half a century,with the rapid development and extensive application of microelectronic technology in the world,computers,frequency conversion drives,projectors and other electronic instruments have been widely seen in our daily life.Industries are increasingly relying on the superior performance of electronic equipment.However,the higher performance of the electronic products,the higher requirement of cooling function it needs.The problem of heat dissipation of electronic equipment has become one of the bottllenecks restricting the technical progress of electronic equipment.At present,the small and high speed centrifugal fan is widely used in the field of ventilation and cooling of electronic equipment.Whether the fan has good heat dissipation performance has a key influence on the operation performance and service life of electronic equipment.In the current information age,electronic equipment is not only widely used civilian equipment,but also widely used in the field of defense science and technology.Therefore,the improvement of cooling efficiency and functional transformation efficiency of the fan is not only related to the daily life of everyone,related to the steady development of electronic equipment,but also related to the progress of national defense science and technology.The small and high speed centrifugal fan with magnetic bearing has become the key research direction of small and high speed centrifugal fan with its advantages of no wear,low noise and good stability.This paper first introduces the history and research status of small high-speed centrifugal fans and magnetic levitation bearings.It analyzes the structure of existing small high-speed centrifugal fans in detail.Based on the small and high-speed centrifugal fan project studied by the engineering and technology research center of magnetic levitation bearing of Shandong university,the structure and optimization design method of radial permanent magnetic bearing are emphatically studied.This paper analyzes different structures of permanent magnet bearing,and gets the conclusion that the double-ring structure of permanent magnet bearings has the highest cost performance.The small and high speed centrifugal fan often works in special environment,so it must have the characteristics of small volume and light weight.In order to conform to the above characteristics,the permanent magnet bearing must also adapt to the volume and weight of the wind turbines,so that it can cooperate with the fan to achieve normal working state.To meet the requirements in such a small volume the design of permanent magnet bearings must take into account various influencing factors.In this paper,the permanent magnetic properties of multiple double magnetic ring structures and single double magnetic ring structures are compared.The fitting degree of this single double magnetic ring is selected.In this paper,Femm software is used to analyze the axial stiffness,rotor clearance and critical speed of permanent magnetic bearing,and the idea of optimal design of magnetic bearing is given.Based on this,the design software of double magnetic ring permanent magnetic bearing is developed.The software uses a combination of Femm and Matlab.It realizes the automation of structural design of permanent magnet bearing.In this paper,the relationship between the axial stiffness,radial stiffness and the critical speed of the system with the length and radial thickness of the bearing is analyzed and studied by using the software programmed.The software also analyzes the relationship between the stiffness of permanent magnetic bearing and the rotor clearance,axial displacement and the logarithm of the double magnetic ring.In this paper,the design and optimization of permanent magnet bearings are further analyzed and discussed,and some experiences are summarized.The research and design in this paper has laid a foundation for the follow-up design and research of small high-speed centrifugal fans.This research results have important theoretical and practical significance.