The technical field includes machine, manufacture, article, process, and product produced thereby, as well as necessary intermediates, which in some cases, pertains to power sources, units thereof, etc.
Depending on the implementation, there is a machine, article of manufacture, method for use and method of making, and corresponding products produced thereby, as well as necessary intermediates and components, regarding a current source that includes current that is not essentially steady direct current, etc.
In alternating current (AC), the movement of an electric charge reverses direction whereas in direct current (DC), the movement of an electric charge is only in one direction; current is accompanied (or caused) by the voltage(s). For perspective, AC is the form of current in which electric power is delivered to most businesses and residences from the grid; DC is the form of current in which electric power is delivered to a flashlight bulb by a battery. The usual AC wave form is more or less sinusoidal, though in certain applications, variations on the sinusoidal form and frequency can be used, such as substantially triangular or substantially square wave form or other less geometric forms tailored to a device requirement. AC or DC can be variable, and AC or DC can be pulsating, i.e., with a periodicity. For example, a DC generator can be randomly throttled so that it produces a variable DC, or it can be throttled with a periodicity (e.g., for a maximum for the period of, say, one minute or less), thereby producing a pulsating DC. Intermittent current can generally be considered DC that is interrupted at intervals, and AC is a type of intermittent current. The intermittency can be periodic or not.
Many aspects of the electrical power infrastructure and applications can use alternating current to enable stepping voltage up or down and to meet specifications of electrical devices. Solar photovoltaic (PV) cells inherently produce DC output which sometimes needs to be converted to AC, such as when being stepped up to feed the grid or to power industrial and consumer devices, such as computers, appliances, etc. This can be accomplished by using an inverter that employs power semiconductors which convert the DC to AC. Another option is to use a DC motor-AC generator combination.
Some, but not all, embodiments herein are generally directed to producing NESDC (Not Essentially Steady Direct Current) without the need for power semiconductors as are used in inverters today. For example, embodiments herein may, but are not necessarily required to, be implemented in part mechanically so as to produce NESDC, e.g., AC (any wave form), pulsed or variable (periodic or not), intermittent (periodic or not), a combination of AC and DC (any wave form), or separate or combined generation of both.
By passing a shadow between a radiation (e.g. light) source and a convertor (a photovoltaic cell or other device that converts radiation into electrical current), such as a photovoltaic cell, thermovoltaic cell, micro TEG device (low thermal mass) etc., current from the convertor can be turned on or off, to the extent shown in U.S. patent application Ser. No. 12/566,327 and Ser. No. 61/194,114, both of which are incorporated by reference herein as if fully stated. However, improving thereon, there can be one or more convertors located to produce NESDC by repeatedly shadowing the convertor from exposure to radiation such that at least some of the radiation shadowed from the convertor either produces electricity or is reflected to an emitter which subsequently reemits radiation to the convertor.
In some embodiments, a device (a vane which intermittently interrupts radiation to a convertor so that the convertor intermittently produces current) employs at least one reflector that reflects some of the interrupted radiation back to the emitter or to another emitter. This reflected radiation serves to heat the emitter (and/or another emitter) and thus is not “wasted.” Therefore, less fuel or energy is required to maintain the emitter at a given temperature. To exemplify, consider an implementation in which reflectors intercept 50% of the emitted radiation and reflect that radiation back to the emitter, while the other 50% is received by one or more convertor to produce NESDC. While the power output is reduced by 50%, less fuel or energy is required to maintain the emitter at a given temperature. However, in another configuration, while shadowing one convertor, a reflector can intercept 50% of the emitted radiation and reflect that radiation to another convertor, to produce NESDC. In the case where the entire vane is coated in convertors that produce DC, all of the light is utilized to produce either DC or NESDC electricity and no shadowing reflector is utilized. Reflectors are still possibly utilized in the design of the convertors and a mounting structure for them. Thus reflectors can be used to improve efficiency and lower heat load by filling gaps between convertors and covering electrical leads and other non-Converter materials such that any radiation that is incident upon them is reflected back to the emitter or a further convertor.
In some configurations, oscillating or rotating vanes can be employed to shadow the convertor(s) and support the reflectors. By varying (for example) the respective width and/or speed of the vanes, reflectors, convertors, and emitters, and by combining output from convertors, a range of NESDC frequencies can be efficiently produced. Indeed, by having convertors and/or vanes of differing widths within the same overall unit, multiple frequencies of NESDC can be simultaneously produced.
In some configurations, a convertor can be located adjacent to a reflector, and another convertor can be located on the underside of a vane, such that radiation from the emitter, angled toward the convertor that is located adjacent to the reflector produces current when not shadowed by the vane, but when shadowed, the reflector adjacent to convertor reflects the radiation up to the convertor that is located on the bottom of a vane. Thus configured, the convertor adjacent to the reflector could produce intermittent DC in one direction, and when shadowed such that the radiation instead is reflected by the reflector, the radiation produces, from the other convertor on the bottom of the vane, intermittent DC flowing in the opposite direction, collectively producing AC. Alternatively, the current from the convertors can be combined in the same direction, and in either case, produce NESDC individually or collectively.
In some embodiments, vanes can be oriented as a cylindrical “squirrel cage” with, for example, 50% of the area of the cylindrical face covered by the reflectors and 50% open to allow the radiation to pass through. When the reflective surface(s) are not 100% reflective across all wavelengths of light and infra-red radiation emitted, and the reflective surface and thus its support will heat up. This can be especially pronounced in vacuum as the only mechanisms for cooling are radiative and conductive along the support(s).
A suitable reflective material can maintain a very high reflectivity and potentially high temperatures for situations where the vane is not actively cooled or heat sunk. Suitable metals include the transition metals that can maintain a polished surface and have a high melting point. Gold and Silver are suitable where high temperatures are not encountered. Metals Tungsten, Molybdenum, Rhenium, Osmium, Iridium, and Platinum can be used for higher temperature reflectors, as can ceramics.
A rear surface of the vane will be facing the convertors in some configurations. This rear surface can be hot and can radiate towards the convertor. Where a shadow is desired, the emission temperature can be kept low.
One series of embodiments can have a backing for the reflective material that is substantially thermally conductive, e.g., copper, aluminum, or some other metal or alloy. The backing can be thermally in communication with a cooling system, e.g., the backing containing a circulating fluid or being thermally connected to a cooled heat sink.
Another series of embodiments, which can be used independently or in conjunction with an active or passive cooling system, has a high emissivity rear surface to allow a vane to radiate heat efficiently and lose energy through radiation cooling. The choice of a material having a high emissivity, such as carbon, allows the vane to radiate at a relatively low temperature. Resultant emission can then be below a threshold for electron production in the convertor, thus maintaining the shadowing effect.
Further embodiments incorporate one or more convertors placed on a rotating surface that is not occluded by the vanes, thus producing DC from the rotating convertors and AC from the fixed and periodically shadowed convertors, e.g., in applications where both DC and AC power are needed for a generator and/or load.
In further embodiments, additional vanes can be placed between the convertors and the emitter(s) such that up to essentially 100% of the emitted light is reflected back. If all the vanes are closed they will behave like a venetian blind. This enables the device to be placed in standby; maintaining a given temperature for the minimum amount of fuel. In this mode the unit could be considered to be blanketed or in “idle” mode. Such a standby mode could reduce the amount of fuel being consumed and allow for an essentially instantaneous startup or a faster start up than is feasible from cold.
When the unit is synchronized to operate in conjunction with other devices or the grid, a motor or other means driving the rotating vanes can be controlled with a control circuit or a feedback device to ensure that the frequency and phase of the output electricity complies with the required performance.
In some embodiments, the rotating vane(s) may be placed inside an evacuated enclosure. The amount of energy required to maintain the rotation will only need to overcome bearing friction as there will be no air resistance. The amount of power used to perform this function can be trivial compared with the power produced by the unit, will largely be independent of the power of the unit, and also will be largely independent of the throttling of the emitter.
As the shadow sweeps across the convertor, the amount of current output from the convertor will decline until it reaches zero, if the convertor is completely shadowed from the emitter. As the shadowing device continues to move past the convertor, the current will again begin to flow and reach a maximum once the shadow has been removed.
The shape of the waveform can be adjusted by varying the shape of the shadowing device. The shadow can be swept across the convertor in a linear fashion with the edge parallel to a square or rectangular convertor, but other configurations can be implemented. For example, an embodiment can have a shadowing device that crosses the convertor at an angle or curve (e.g., 45 degrees) so as to initially cover a small portion of the convertor and gradually cover more and more at an increasing rate. Once 50% of the convertor is covered, the reverse effect can occur with the trailing edge as the remaining 50% is swept. This approach can be implemented so as to create any desired waveform. In the case of the 45 degree sweep over a square area, an approximately sinusoidal form is output. If a differing waveform is desired, for example to drive a particular motor or load, the shape and/or slope of the shadow can be configured or even adjusted, as can the shape and/or slope of the convertor, etc.
In some embodiments, convertors can be connected with opposite polarity to achieve alternating current. For example, sinusoidal AC could be produced by having two oppositely wired convertors mounted back-to-back that spin at a constant rate so that the convertors are alternately exposed to the emitter. AC could also be produced by connecting the output of a DC convertor to a transformer, with the DC convertor alternately illuminated by the emitter and then shadowed.
To simplify the teachings of this specification, certain conventions are used. Consider that a way of articulating the shadowing with respect to a convertor is to view a convertor as stationary and a means for shadowing the convertor as moving so as to interrupt a path of radiation from an emitter to the convertor, e.g., vanes (like those on a windmill) rotate to interrupt a path of radiation from an emitter to a convertor. However, this perspective is arbitrary, and one could equally view the convertor as moving through a stationary shadow, e.g., the vanes being stationary while the convertor moves in and out of the path of radiation from the emitter. One could equally view the convertor and the means for shadowing as both moving oppositely, i.e., neither is stationary. Even yet further, one could equally view the emitter moving instead, or in combination with, movement of the convertor and reflector. In view thereof, only for the sake of consistency and simplification, this specification will at times, but not always, adopt the convention of referring to the emitter and the convertor as being stationary, with the explicit understanding that in many embodiments, they are not. Similarly, a teaching herein with respect to a particular emitter 4, convertor 6, reflector 8, or vane 5 (each in the singular) is applicable to each in the plural, e.g., emitters 4A, 4B, etc., convertors 6A, 6B, etc., reflectors 8A, 8B, etc., and vanes 5A, 5B, etc. Again only for the sake of consistency and simplification, this specification will at times, but not always, adopt the convention of using the singular, with the explicit understanding that in many embodiments, they are not. Additionally, the emitter can be an emitter of light, heat, and/or other radiation, and correspondingly, a convertor can be a photovoltaic (PV) cell, thermovoltaic (TV) cell, etc. In some embodiments, the emitter can be comprised of a hot emitter and the convertor can be one or more photovoltaic cells that convert the emitted radiation into electric power, such as in a non-limiting example as disclosed in Ser. No. 60/833,335; 60/900,866; Ser. No. 11/828,311, and Ser. No. 12/375,176, all of which are incorporated by reference as if fully restated herein.
With this in mind, then, turn now to the figures, wherein
There can be one or more vanes 5 disposed for movement which produces the shadowing. In some implementations, a vane 5 can support or be comprised of at least one reflector 8, e.g., 8A mirrored to reflect the radiation to the emitter 4A. In some implementations, a vane 5 can support or be comprised of at least one convertor, e.g., convertor 6B. When the orientation with respect to vane 5A changes toward the position of the dotted line and onward, eventually convertor 6A will be shadowed from the path of radiation from emitter 4A, and reflector 8B will reflect the radiation up to the emitter 4B, following a path in part suggested by the asterisked lines, while convertor 6C would be exposed to the radiation path from emitter 4A.
While
As an additional teaching, (not shown in
Alternatively, (not shown in
As an alternative, or in combination with the rotation, the configuration in
Illustratively with respect to a diode configuration,
For example, the control circuit 14 can include a frequency generator, such as a crystal oscillator. In this case the select frequency 16 could be a number by which the frequency generator output is divided by to set the frequency of the signal to the motor 18. For example, the frequency generator could generate a 1 MHz signal, and the select frequency 16 input could be the number 10000, so that the frequency sent to the motor 18 would be 1 MHz/10000=100 Hz. Depending upon the design of the motor 18, it could then rotate at 100 Hz, or perhaps at half the input frequency, 50 Hz. In other embodiments, the input frequency could be derived from the electrical A/C 12 input. A particularly simple embodiment of the control circuit 14 is to drive the motor 18 directly from the electrical A/C 12 input so that the motor 18 remains phase locked with the input electrical A/C 12. In some other embodiments, the Control Circuit 14 could receive feedback from the detector 6 (feedback not shown in
Control circuit 14 governs motor 18 having a shaft that, in this teaching example, has vanes 5. Vanes 5 rotate to interrupt the path of radiation communicated from emitter 4 toward convertors 6 with reflectors 8, which reflect the radiation toward emitter 4 for being re-emitted so as to be received by convertors 6. Convertors 6 produce current that is communicated to output combiner 20, which combines the current from convertors 6 so as to produce the output 22, i.e., NESDC. Though not shown in
The configuration of output combiner 20 may, to a degree, reflect the particular implementation desired. Consider, for example, an embodiment that could be used to produce 3-phase current from the apparatus shown in
The motor 18 can, but need not, be in the form of an induction motor with coils internal or external to the unit 2, i.e., an induction motor can be oriented to move the vanes 5 without direct electrical contact. The motor 18 can bring about the shadowing by rotating one or more rotating vanes 5 spaced and rotated at a speed that produces the intermittent current at a frequency between and including 10,000 and 100 megahertz, between 1 and 10,000 hertz, at 400 hertz, at 60 hertz, or at 50 hertz, depending on the configuration and use desired for one application or another. By utilizing hair thin devices and a fast rotation speed, surprisingly high frequencies are attainable up to at least 1 gigahertz. By utilizing standard semiconductor chip production methods, very narrow PV cells can be manufactured adjacent on the same substrate thus allowing for very high frequency NESDC if desired.
If the motor is powered off of the grid, the rotation can be in phase with the grid and this will enable the resulting NESDC to also be in phase with the grid.
The reflector 8 may, if desired, have an insulating or cooled backing. The backing, if so desired, may comprise molybdenum, silver, gold, tungsten, for communicating heat. The backing, if so desired, may comprise an insulating backing, such as a backing which includes zirconia, alumina, silicon carbide, magnesium oxide, a ceramic, etc.
Note that the necessity or suitability of components for one embodiment or another will depend on the particular implementation desired. So for example, there can be an implementation along the lines of a Crookes radiometer configuration, illustrating that an emitter, like the sun, can cause rotation of the convertors and/or reflectors. In this configuration, there would be no need for a motor. The point of this teaching is that the necessity or suitability of components depends on the particular implementation that is desired.
In any case, the relative size, spacing, shape, angle, speed of rotation, and/or speed of oscillation of the vanes 5 with respect to the convertors 6, etc. can each individually or in any combination thereof, determine the shape and frequency of the varying current produced by the unit 2. Similarly, the relative size, spacing, shape, angle, speed of rotation, and/or speed of oscillation of the reflectors 5 with respect to the convertors 6, etc. receiving reflected radiation can each individually or in any combination thereof determine the shape and frequency of the varying current produced by the unit 2. Further, there are other ways to enable selection of the current output, e.g., relative size of the unit and its components, the percentage shadow coverage at each point during movement. For example, the rate of movement and the rate of acceleration with respect to the change in orientation can drive a particular waveform when convoluted with the power curve for the convertor 6. Illustratively, then, unit 2 can be configured to produce AC, e.g. by having oppositely wired convertors alternately exposed to the emitter, AC with a substantially sinusoidal wave form, e.g., by having two oppositely wired convertors mounted back-to-back that spin at a constant rate so that the convertors are alternately exposed to the emitter; DC, e.g., by having a convertor on a vane continuously exposed to the emitter; intermittent DC, e.g., by arranging convertors so there are periods of time when all convertors are shadowed; variable DC, e.g., by having convertors arranged variably, and/or by having vanes arranged variably; periodic DC, e.g., by having convertors arranged periodically, shadowed by periodic vanes that rotate at a constant rate; AC separate from the DC, e.g., by having convertors mounted on vanes to provide DC, and having alternately exposed convertors wired oppositely to provide AC; DC and AC, such that at least one of the DC and AC is variable, e.g., by having the convertors arranged variably; DC and AC, such that at least one of the DC and AC is pulsed.
In sum, appreciation is requested for the robust range of possibilities flowing from the teachings herein. More broadly, however, the terms and expressions which have been employed herein are used as terms of teaching and not of limitation, and there is no intention, in the use of such terms and expressions, of excluding equivalents of the features shown and described, or portions thereof, it being recognized that various modifications are possible within the scope of the embodiments contemplated and suggested herein. Further, various embodiments which implement the general teachings are to be viewed as included herein because the disclosure herein has been described with reference to specific embodiments for teaching purposes, such that the disclosures are intended to be illustrative and are not intended to be limiting. Various modifications and applications may occur to those skilled in the art without departing from the true spirit and scope defined in the claims.
Thus, although only a few exemplary embodiments have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages herein. Accordingly, it is respectfully requested that all such modifications be included within the scope defined by claims. Means-plus-function language and claims, if any, are intended to cover the structures described herein as performing the recited function and not only structural equivalents, but also equivalent structures. Thus, although a nail and a screw may not be structural equivalents in that a nail employs a cylindrical surface to secure wooden parts together, whereas a screw employs a helical surface, in the environment fastening wooden parts, a nail and a screw may be equivalent structures.
The present patent application claims benefit from U.S. Ser. No. 61/735,735, filed on Dec. 11, 2012, being incorporated by reference completely as if restated totally herein.
Number | Date | Country | |
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61735735 | Dec 2012 | US |