Research On Theory Of Magnetic Suspension Supporting System And Application For Flywheel Battery

Owing to many unique performances, flywheel battery has been becoming a new member of the battery family, and has been taking the place of the chemical battery in many aspects. Along with the fast development of new composite materials, rare earth permanent magnet, electrical machine technology, magnetic suspension technology and power electronics, its application has involved aerospace, electric vehicles, distributing power generation system, electric power quality and energy storage generation, uninterruptible power supplies (UPS), and so on. This paper goes deep into a thorough research on the system scheme of the flywheel battery, theories & calculation methods of the magnetic suspension system, and its application to the distribution generation.The primary innovations of this paper are as follows:A new-type magnetic bearing is proposed, and is called as the electromotive magnetic bearing. Its operational principle, rotor's magnetic force, bearing's stiffness and stability, and so on, are studied in detail. The calculation theories and methods of the suspension force, stiffness, lowest rotating speed and critical damping on the electromotive magnetic bearing are proposed. The theories and methods on the spatial magnetic field's calculation of the permanent magnet are systemically presented. The integral formulae of the spatial magnetic field's calculation on the permanent magnet are derived according to equivalent magnetic-charge model and equivalent electric-charge model respectively, and the analytic formulae of the spatial magnetic field's calculation on the symmetrical permanent magnet are derived along their axes. By use of FEM, the theory and method on the spatial magnetic field's calculation on the inhomogeneous, anisotropic medium is presented. The configuration synthesis is presented, and theory & method of suspension force's calculation on the permanent magnetic bearing are proposed. According to topology, studies the configuration synthesis of the permanent magnetic bearing, and presents a few kinds of common configurations. Magnetic Maxwell stress tensor is derived by use of vector, dyadic and tensor operation, and the computing theory & method of the suspension force on the permanent magnetic bearing is developed and perfected according to Maxwell stress tensor. Combined with FEM and vector differential operation, the computing theory & method of the suspension force on the permanent magnetic bearing is developed and perfected according to virtual work principle. Theory & method of stiffness calculation on the permanent magnetic bearing are presented. By use of scalar and vector differential operation, combined with FEM, theory & method of stiffness calculation on the permanent magnetic bearing are presented. By the examples of the permanent magnetic bearing, the bearing performances with a common structure and a cone-shaped structure are analyzed respectively.A new-type magnetic suspension support system that is used to suspend the rotor of the flywheel battery is proposed, which is made up of the electromotive magnetic bearing and the permanent magnetic bearing with a cone-shaped magnetic gap. The system control scheme of the output on the solar energy power plant involving the flywheel battery is proposed, and the principle and method of SPWM used to adjust the breadth, frequency and waveform of the output/input voltage on the motor/generator are analysed. By the example of the civil house with 2kW load, simulate the energy variation of the flywheel battery, the power variation of the motor/generator and the speed variation of the rotor.