Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
2003-12-19
2004-09-21
Ponomarenko, Nicholas (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S090000, C310S090500, C310S06800R, C310S06800R
Reexamination Certificate
active
06794777
ABSTRACT:
BACKGROUND OF THE INVENTION
Flywheel power storage devices, and the various elements needed for their implementation, have been set forth in the prior art, having various forms and combinations. Numerous recent flywheel patents describe devices intended to serve as electromechanical batteries, which store kinetic energy in a spinning flywheel and generate electric power from it when needed. A safe, cost-competitive, practical and care-free flywheel power storage and regeneration system can provide a very attractive alternative to electrochemical batteries used in UPS (Uninterruptible Power Systems). Electrochemical batteries subjected to frequent deep-discharge have short service lifetimes, low reliability, need for costly and frequent maintenance, temperature limits that may compromise applicability, performance and reliability degradation while in use, and poor energy recovery efficiency. UPS is mostly used as on-site backup for conventional utility power distributed extensively to stationary sites connected to power grids.
In addition to storing and regenerating power onboard a spacecraft, especially an orbital satellite, practical electromechanical batteries, in system combinations, can also provide inertial attitude control for such a spacecraft. Orbital satellites are launched for global communications, radio, television, mapping, weather prediction, and myriad useful purposes.
My present invention includes improvements and enhancements, over teaching set forth in my U.S. Pat. No. 6,566,775. That invention mainly teaches a minimal-loss flywheel battery. It teaches means for achieving virtually zero “idling loss” (an electromechanical battery property that may be compared to electrochemical battery “trickle charge”) while its magnetically levitated rotor spins at high speeds, with configurations that avoid magnetic cycling of magnetic materials, and that block and buck eddy currents in stator windings. That patent also teaches motor/generator means for ultra-high electromechanical power conversion efficiencies and nearly zero power loss while coasting at all speeds, and systems that can have virtually unlimited service life without need for maintenance. It also teaches power interface electronics, that exchange current with its DC (direct current) power buss and its motor/generator. And it teaches magnetic levitation means that require virtually zero steady-state power.
A high-speed radial-field regenerative motor, having virtually zero idling losses, is set forth there. It serves as a motor/generator, that alternately stores and regenerates power as needed. Its integral rotor assembly is configured to accommodate high spin speed without disintegrating from centrifugal forces, and to sustain virtually zero idling losses in a vacuum environment. Its power interface electronics controls current between the motor stator and a DC power buss, and is responsive to a variety of command signals. So the power electronics of a number of systems can be connected in parallel, to a DC power buss.
The present invention provides improvements over my U.S. Pat. No. 6,566,775. Both include a radial-field embodiment with non-contacting magnetic levitation, of a regenerative brushless DC motor. It is a flywheel version of the motor taught in my U.S. Pat. No. 4,520,300 for a coreless axial-field ultra-efficient regenerative servo including its electronic power control interface.
The flywheel assembly described in my U.S. Pat. No. 6,566,775 clearly is susceptible to an earthquake that might subject its external support structure to a free-fall. Only gravitational force acts to oppose axial magnetic attraction of its axial magnetic support. So subjecting the system to free-fall would cause the axial servo of its magnetic support to lose control.
Also, during a severe earthquake, the bi-directional current of its axial electromagnet coil may reach high levels at a polarity that induces reverse magnetic field on the concentric axial magnet. That may weaken the magnet by partially demagnetizing it.
Accordingly, an objective of this present invention is to remove those limitations, without increasing overall system losses, complexity, and production cost, or necessitating external devices such as shock absorbing mounts that would only mitigate such external disturbances.
Also, gravitational force is essential to proper operation of the flywheel battery axial and radial servos, described in U.S. Pat. No. 6,566,775. That would preclude use aboard a spacecraft. Accordingly, another objective of the present invention is to provide a “weightless” environment embodiment especially suitable for use on orbital satellites, where flywheel system combinations can provide power storage and regeneration, plus attitude control.
A flywheel system with permanent magnets that support up to 90% of rotor weight is described in U.S. Pat. No. 6,262,505 by Hockney et al. That invention includes a cooperative electromagnet, to stabilize its otherwise unstable magnetic axial support. It also adds nominally 10% to total lift forces. No electromagnet current reversal means are described. So clearly, various external factors, such as an earthquake, or a temperature change that increases the magnet's strength, which might reduce the electromagnet current to zero, would result in loss of axial position control. Also, that invention includes radial journal bearings with shock absorbing properties and clearances selected to limit off-center radial excursions. They would be subject to wear, that would reduce service life and contaminate a crucially needed vacuum.
Other configurations are described in U.S. Pat. Nos. 5,627,419 by Miller; 5,760,510 by Nomura et al; 5,777,414 by Conrad; 5,319,844 by Huang et al; and 5,844,339 by Schroeder et al. Yet other configurations are described in U.S. Pat. Nos. 5,705,902 by Merritt et al; 5,044,944 and 5,311,092 by Fisher; 5,107,151 and 5,677,605 by Cambier et al; 5,670,838 by Everton; also 5,708,312 and 5,767,595 plus 5,770,909 by Rosen et al.
These flywheel systems are representative of prior art that does not quantitatively address their idling losses. Without continual power input, their energy would be typically dissipated in less than an hour, due to high hysteresis and eddy losses. This energy loss, without supplying output power, is far worse than self-discharge exhibited by most electrochemical batteries.
None of these configurations, nor any other prior art, include the minimal-idling-loss means of the motor/generator, power interface electronics, and magnetic support elements, described in U.S. Pat. No. 6,566,775 and improvements plus enhancements thereto of the present invention.
Magnetic levitation without electronic servo loops is described in U.S. Pat. Nos. 5,495,221 and 5,783,885 plus 5,847,480 and 5,861,690 plus 5,883,499 by Post. Magnetic bearings, for use in flywheel batteries, that employ hysteresis and eddy effects, for moving mechanical devices, to adjust physical positions of magnetic materials for axial stability, confront serious stability and reliability problems. Axial lift-off by repulsion forces between fixed conductors and a spinning Halbach magnet array, may result in rotor lift and stabilization at speeds above those needing mechanical bearings for rotor support. But this method confronts high idling losses and high stray magnetic fields, from eddy currents required for both lifting and stabilizing their rotor assembly. Mechanical bearing wear and lubrication would also be troublesome. And they would confront formidable stability problems, because there is so little chance to optimize dynamic behavior. Conversely, the electronic servo loops controlling electromagnet actuators described herein, which comprise key elements of the present invention, are readily optimized.
Vacuum loss in some prior art would necessitate relatively frequent maintenance to keep windage loss at acceptably low levels. In turn, need for a vacuum enclosure that can be opened for frequent maintenance, further degrades the interior vacuum soon after re-closing an enclosure needing fle
Mohandesi Iraj A.
Ponomarenko Nicholas
LandOfFree
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