Prime-mover dynamo plants – Electric control – Fluid-current motors
Reexamination Certificate
1999-05-03
2001-10-09
Ponomarenko, Nicholas (Department: 2834)
Prime-mover dynamo plants
Electric control
Fluid-current motors
C290S054000, C322S029000
Reexamination Certificate
active
06300689
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to the generation of electric power from a source of energy whose energy output is highly variable and, in particular, to the efficient generation of electrical power even when the amplitude and frequency of the energy supplied by the source of energy vary over a wide range.
There is growing interest in obtaining electrical power from “clean” sources of energy such as ocean waves and/or air currents. However, these “natural” sources of energy produce energy whose amplitude and frequency vary widely. As a result of these variations, even where a system exists for capturing energy present in ocean waves and/or air currents, a problem exists in how to efficiently transform the captured energy into electric power.
For purpose of illustration, the generation of power from ocean waves will be used in the description to follow. Capturing the energy present in ocean waves is problematic because the amplitude of the waves is constantly varying and the frequency (or period) of the waves also varies constantly. An additional problem in capturing the constantly varying energy present in ocean waves is to do so efficiently because, in typical power conversion systems, the efficiency of power conversion falls off rapidly when the system is operating outside of a relatively narrow range of power conversion rates.
SUMMARY OF THE INVENTION
An electric power generating system embodying the invention includes a mechanical means for capturing energy available from a natural source of energy, where the energy available from the source varies in rate, amplitude and frequency. The variable mechanical energy thus captured is used to drive a generator at a variable rate of rotation. It is known that, dependent upon the parameters of the generator used, for each speed of rotation of the generator, there exists a corresponding preferred output voltage of the generator at which the efficiency of conversion of mechanical energy to electrical energy is a maximum.
In accordance with this invention, both the speed of operation of the generator and the output voltage of the generator are sensed. Then, in response to these sensed values, the impedance of the load into which the generator output power is fed is varied for driving the voltage thereacross towards that preferred output voltage of the generator corresponding to the maximum efficiency operation of the generator at the actual sensed speed of operation of the generator.
In a preferred embodiment, the generator load comprises a capacitor. The generator output power (in d.c. form; either directly from a d.c. generator or rectified from an a.c. generator) is fed directly into the capacitor, and the voltage across the capacitor, corresponding to the output voltage of the generator, is continuously monitored. Simultaneously with the feeding of power to the capacitor, power is extracted from the capacitor during spaced apart short time intervals. By varying the rate of power extraction from the capacitor relative to the rate of power fed thereto by the generator, the voltage across the capacitor is driven towards a preferred voltage corresponding to the instantaneous sensed speed of operation of the generator. The preferred generator output voltage is obtained based upon the known speed versus preferred generator output voltage characteristic of the generator being used, e.g., by calculation or by the use of a look-up table or the like. The rate of power extraction from the generator is controlled in response to an error signal obtained by comparing the sensed output voltage across the capacitor against the looked-up preferred generator output voltage corresponding to the sensed speed of operation of the generator.
REFERENCES:
patent: 4891744 (1990-01-01), Yamamoto et al.
patent: 4973896 (1990-11-01), Shiga et al.
patent: 5083039 (1992-01-01), Richardson et al.
patent: 5406190 (1995-04-01), Rosenberg
patent: 5559685 (1996-09-01), Lauw et al.
patent: 5903116 (1999-05-01), Geis et al.
patent: 5942818 (1999-08-01), Satoh et al.
Ocean Power Technologies, Inc
Ponomarenko Nicholas
Schanzer, Esq. Henry I.
LandOfFree
Electric power generating system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Electric power generating system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Electric power generating system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2617141