| Flywheel battery is a novel energy storage device which can realize energy conversion between mechanical energy and electric energy. It has many advantages including high energy storage,high power,no pollution,high storage efficiency,wide application,noise free,long cycle life,and so on. Flywheel battery is a typically electromechanical and electromagnetical product with some main parts:high speed flywheel,magnetic bearing system,motor/generator,etc. The study of flywheel battery concerns the intercross of many disciplines,such as mechanism,material,electronic engineering,heat engineering,computer,and so on. In this dissertation,two main key techniques,the high speed flywheel rotor and the magnetic bearing,are investigated deeply and systematically.The main contents of this dissertation are as following:In Chapter 1,the background,source,purpose and significance of the subject are introduced. The principle and key techniques of energy storage for the flywheel battery are analyzed. The international research situation and application prospects of flywheel battery are also presented. Based on this,the author brings up the main studying contents of this dissertation.In Chapter 2,the energy storage ability of the flywheel battery and its affecting factors are analyzed. The energy storage ability of different material flywheels are compared and analyzed. On the basis of the analysis of all sorts of stress analysis methods,the stress distributions of flywheel rotors with different structures and different materials are analyzed quantitatively and compared. The computation expressions of the stress for composite flywheel are derived. The affecting factors on the stress distribution for the flywheel rotors are analyzed and investigated. And the design method of structure parameters for the flywheel rotor is presented.In Chapter 3,the stability of permanent magnet bearings is analyzed. And the modified methods which can improve the stability of the permanent magnet bearings are studied. The computation expressions of the magnetic force and stiffness of the permanent magnet bearings are derived. The characteristics of the magnetic bearings with different structures are studied. The analysis method is presented,which can analyze the mechanical characteristics of permanent bearings by using finite element method. And the influence of the structure parameters on characteristics of the bearings is studied.In Chapter 4,the basic theory of magnetic bearings is investigated. Based on the analysis of the magnetic circuit,the computation expressions of the magnetic force,magnetic flux density and inductance are derived. Two calculation methods of the electromagnetic force are studied for two typical configurations of the magnetic bearings. One configuration utilizes the permanent magnet to provide a bias flux and the other configuration has no source of bias flux. Based on the simplified analytical model,an improved analytical model is developed by adding correction factors to thesimplified model. The characteristics of the magnetic bearings are studied based on PD and PID control strategies.In Chapter 5,based on the analysis of all sorts of topology structures of magnetic bearing systems,one single-axis controlled system structure of hybrid magnetic bearings for flywheel battery is presented,which is made of two radial permanent magnet bearings and one axial magnetic bearing. The computation of the structural parameters and the suspension characteristics of the magnetic bearing system are analyzed and discussed in details. And the system dynamic model is built.In Chapter 6,on the basis of the above theory studies,the design process and method of the flywheel battery is presented. The feasibility of the design method is also verified through the designing a small flywheel battery device. The design contents include the design of the flywheel rotor of metal and composite materials respectively,the structure computation of the permanent magnet bearing and magnetic bearing,the control design of the magnetic be...
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