JPH0315237A - Storage of electric power by means of annular flywheel - Google Patents

Abstract

PURPOSE:To permit the accumulation of energy into a flywheel by a method wherein an annular rotary body, constituted of only a rim and having no rotor shaft, is levitated by contactless levitation through magnetic force and the like and is turned in a high speed. CONSTITUTION:A flywheel, constituted of only a rim and having no central shaft, is rotated. According to this method, energy equivalent to the tensile strength of a material, is accumulated. Even when a rotary body is not provided with a shaft, a super giant ring may be slid in a vacuum tube when the annular rim is levitated and turned by magnetic levitation like as a magnetic levitation train. The selection of an installation place may be facilitated since there is no shaft whereby the size of the flywheel may be increased to a giant size.

Description

[Detailed Description of the Invention] (1) Purpose of the Invention It would be ideal if electric energy could be generated in the required amount as needed, but it is not possible to do so in a way that is convenient for humans. When we need a large amount of energy by accumulating this energy, it would be very convenient if we could extract the energy accordingly. In the case of Japan, which has a large power system, the electricity situation is so good that it can be considered as if electricity energy is supplied as much as desired. Still, the scale of power application plants has increased, and steel production! 2 Power fluctuations and flicker have been a problem in the steel industry for a long time, but in the future, for example, nuclear fusion experimental equipment, driving power for magnetic levitation trains, medical particle accelerators, and pulsed high-power applications will continue to increase. no doubt.

For example, the fusion experimental facility f constructed at the Japan Atomic Energy Research Institute
iJT-60 toroidal magnetic field coil 'F4. The power source receives 160,000 kW from the power grid, which is half of the 320,000 kW required by the peak, and the rest is supplied by a generator with a flywheel. This is because the frequency fluctuation limit of the power system is ±0.05 Hz, which limits the pulse to 160,000 kW that can rise in 30 seconds. This generator with flywheel is the world's largest flywheel (weight 6
It can store 8GJ of energy and release half of it, 4GJ, with a maximum output of 200MW.

It has been in operation without any problems for five years since it was completed. In this way, energy storage using the ancient flywheel plays an important role in future energy development.

(2) Industrial application of flywheels This flywheel, which was developed as part of nuclear fusion development, exceeds the scale required for industrial use in terms of energy consumption and aerodynamic output, and if the issues of efficiency and price are solved, it can be widely used. Things that become popular-
We are currently considering this. Table 1 shows the volume density of energy, and the flywheel is five times larger than magnetic energy, and has a very high conversion efficiency of 98% to electricity. If super-synchronous Shelbius control technology is adopted here, the flywheel can be operated at variable speed while keeping the input and output frequencies constant. Regarding idling loss, the JT-60 rotates in the atmosphere without special bearings and has an energy storage time constant (if product energy/loss) of 1600 seconds, which is well suited for industrial load fluctuations of about 100 seconds. There is.

(3) Huge ring-shaped flywheel When the radius of the flywheel is increased, its energy increases and the storage time constant also increases. With conventional disks, stress is concentrated in the center, and the structure is limited to withstand the stress there. By rotating only the rim without a central axis, the flywheel proposed here generates energy that is full of the tensile strength of the material! This is what we are trying to accumulate.

Even if there is no shaft for the rotating body, if the ring-shaped rim is suspended and rotated like a magnetic 4-wheel train, a gigantic ring can be slid into a vacuum tube. The fact that there is no axis makes it easy to choose a 3M installation location and it can be made large. This is where the concept of a giant ring-shaped flywheel to store energy was born in a vacuum tube underground railway that carries no passengers.

When the ring is rotated, the tensile stress is δ, = ρ(rω)2 (Formula 1) ρ is the density kg / m ' r is the radius, ω is the angular velocity energy E is E = Iω2/2 (Formula 2) ■ is rotation Since the moment E = ρ2πr'SS is the cross-sectional area, E = δtπrs (Equation 3), and the energy is determined by the radius r and the tensile strength δ. A material with strong tensile strength is best, and if used to its limit, FRP can reach 300 J/cc. 90 J for #4 iron
/cc energy M! The R density is obtained. (4)
Example Using high flaw strength steel as a tensile strength material δ, = 90kgf/mm2 ρ: 7.8t,/
13, the speed is 340m/s and the radius is 25
In m, the cross-sectional area is 1 m? So the energy of 70GJ is M
114.

As an example of a ring rotor, a conceptual diagram is shown in Figure 1.
cycloconverter) is placed on the rotor.

1! A frequency equal to the difference between the number of revolutions of the rock and the rotor is generated, and the 78 forces required for this purpose are sent in and out through non-contact magnetic coupling. This may also be part of the magnetic levitation and guide. It may be necessary to fill the underground tubes with low-pressure hydrogen or helium for cooling.

The superiority of mechanical energy can be clearly seen by comparing it with the University of Wisconsin's 10 million kWh design example for superconducting energy storage. This energy is multiplied by N in a huge volume with a maximum magnetic field of 6T, but compared to this, if the ring flywheels were lined up, the radius would be 160m. Isa 100
This is achieved by running a ring with a magnetic flux of %ll at a speed of 340m per second over a cross section of a 0m underground tube of 10xlOm. There are buildings in the center, so there are no problems with pollution or noise. This would be possible within the scope of the technology currently in progress. If we make the radius even larger and run it inside the underground tube along the JR Yamanote Line, the stress in the material can be reduced to 20 kg.
Even as f/me2, energy exceeding 100 million kWh is M
flJ! can.

[Brief explanation of the drawing]

Table 1 shows a comparison of energy densities by storage methods. Figure 1
is a conceptual diagram of a ring flywheel. Figure 2 shows an example of a 10 million kWhlff energy flywheel and an energy storage SMES using superconducting coils side by side. (1) Magnetic levitation and guide (also supplies excitation power)
(2) Cycloconverter for field excitation (3) Field (4) Armature (5) High-strength steel (6) G-pressure device (7)
AC/DC converter and transformer (8) Superconducting coil (9) Magnetic shield (10) Ring flywheel (1 1) Magnetic thickness equipment density is +bare” storag excluding peripheral equipment
Evaluation by evolume Table 1 Comparison of energy density by storage method (2) Figure 1 (b) SMES Figure 2 Procedure sum tr Ordinary book (method) Contents of correction in page 6, lines 8 and 19. Delete "Table 1 shows a comparison of energy densities by the storage method." Display of the case 1999 Patent Application No. 141382 Name of the invention Person who corrects energy storage using a ring-type flywheel Relationship with the case Patent applicant address 2-1 2-1 Tokyo Institute of Technology Electric and Electronics Co., Ltd., Ookayama, Meguro-ku, Tokyo Date of order to amend Ryuuichi's name in the Department of Engineering: September 26, 1999 Column for a brief explanation of drawings in the specification subject to amendment

Claims (2)

[Claims] (1) A ring-shaped rotating body that does not have a rotor shaft and consists only of a rim. A flywheel that stores energy by levitating it non-contact and rotating at high speed using magnetic levitation, etc. (2) A frequency converter installed on the rotor generates a variable frequency rotating field in response to changes in rotational speed due to increases and decreases in the rotational energy of the flywheel, and the rotational field remains constant regardless of the rotational speed of the flywheel. Flywheel energy storage system that enables storage and release of frequency power