Hiromasa Higasa

Experimental and numerical evaluation of rotation speed degradation of radial type superconducting magnetic bearing

The degradation of levitation force and rotation speed is one of the most significant problems for the practical use of superconducting magnetic bearing (SMB) for flywheel energy storage system. The degradation are called the rotation losses caused by the AC magnetic field due to the inhomogeneous distribution of magnetic flux density of the permanent magnet (PM) rotor. In this research, our simulation method was improved so that the eddy current flowing in the cryostat around the superconductor was taken into account. The dependency of the rotation losses of radial type SMB with cryostat was evaluated by this new simulation method concerning the amplitude of inhomogeneous component of PM rotors field.

AC loss of HTSC bulks for magnetic levitation

Abstract The new simulation method was developed based on the T -method to simulate the AC loss of high temperature superconducting magnetic flywheel when the magnetic rotor rotates with the inhomogeneous component of the magnetic field. The dependencies of AC loss upon some conditions such as the wave number, the amplitude of inhomogeneous component and so on were analyzed.

Experiment of a 100Wh-Class Power Storage System using High-Tc Superconducting Magnetic Bearing

A superconducting magnetic bearing exhibits low rotational loss. Accordingly it is likely to form an efficient power storage system in combination with a flywheel. We developed a 100Wh-class flywheel type power storage system using high-Tc superconducting magnetic bearing. We prepared Y-based oxide superconductors with MPMG method and Pr-based permanent magnets for the magnetic bearing. The flywheel has the maximum diameter of 250mm and weight of 27.5kgf. A storage energy of the flywheel is 0.2MJ(=55Wh) at nominal speed of 17000rpm.

A Feasibility Study of Modeling and Control for 10MWh Class Energy Storage Flywheel System Using Superconducting Magnetic Bearing

As difference of electric power required in day and night has been increasing, an energy storage and a smoothing of electric power in day and night become very important, If energy storage with high capacity could be able to realize, efficiency of electric power system will become higher. An energy storage flywheel system using superconducting magnetic bearing is one of the most useful method of energy storage[1].

Numerical evaluation of rotation speed degradation of superconducting magnetic bearing caused by the electromagnetic phenomena

The degradation of rotation speed is one of the most significant problems for the practical use of superconducting magnetic bearings for flywheel energy storage system. In this research, the rotation loss phenomena are analyzed by simulation and by experiment.

AC Loss of YBCO Magnetic Bearing Covered with HTSC Thin Films

The decreases of rotation speed and levitation force are ones of the most significant problems for the practical use of HTSC bearing. It is caused by AC field due to the inhomogeneous magnetization of the rotor’s PMs. In this research, we propose the HTSC bearing covered with the HTSC thin films that have much larger Jc for suppression of rotation loss, and its effects are investigated by experimental and computational works.

Numerical Analysis of The Levitation Force in HTSC Superconducting Levitation System of A Flywheel

A computer code[l,2] for the numerical analysis of the shielding current in type-II superconductors is upgraded for the purpose of evaluation of the levitation force in a superconducting magnetic bearing of an energy storge flywheel. The levitation force characteristics are numerically evaluated. Furthermore, the relations between the arrangment of the permanent magnets of the rotor and the levitation force are also evaluated for optimization of the levitation system.