1. A solar concentrator apparatus, comprising:
a plurality of dish-shaped reflectors coaxially aligned in an array supported by single moveable elevation spaceframe, said elevation spaceframe comprising a rigid, lightweight, open truss structure that extends in three dimensions and is constructed from struts joined at nodes forming a rectangular framework of struts with diagonal braces, said dish-shaped reflectors having a focus and being adapted to concentrate solar radiation, wherein the plurality of said dish-shaped reflectors each has a converter positioned at the focus of the dish-shaped reflector;
a two-axis tracker supporting said moveable frame, said two-axis tracker being adapted to point the moveable spaceframe in a direction such that the array of dish-shaped reflectors are positioned to receive solar radiation; and
a control device coupled to said two-axis tracker, said control device being operative to move the two-axis tracker so that the array of dish-shaped reflectors continue to receive solar radiation as the sun moves across the sky during a substantial portion of daylight hours;
wherein said converters are operative to generate electrical power when solar radiation is focused upon said converters by a corresponding dish-shaped reflector;
wherein a plurality of said struts of the elevation spaceframe form a plurality of unit reflector cells configured as right prisms with provision to support a unit generator near the focus of a corresponding dish-shaped reflector, wherein each said dish-shaped reflector is supported from lower nodes of a corresponding unit reflector cell and each associated unit generator is supported from upper nodes of a corresponding unit reflector cell;
wherein said elevation spaceframe has a plurality of unit reflector cells in an upper row and a plurality of unit reflector cells in a lower row, further comprising:
a central pedestal supporting the elevation spaceframe, wherein the lower row of the elevation spaceframe has a narrow central cell providing space for an elevation bearing and the pedestal, the elevation bearing having two ends, the two ends of the elevation bearing being supported by stiff elevation nodes, formed as an inherent part of the elevation spaceframe at the intersection of corner struts of the inner unit reflector cells in the lower row, the elevation bearing being placed at the center of gravity of the full elevation structure that turns about the elevation bearing on the central pedestal;
the central pedestal comprising a thrust bearing so that the central pedestal turns about an azimuth axis; and
said two-axis tracker having an azimuth drive for turning a portion of the central pedestal above the thrust bearing in order to rotate the elevation spaceframe about an azimuth axis, and having an elevation drive to rotate the elevation spaceframe about an elevation axis coincident with said elevation bearings;
wherein said dish-shaped reflectors are monolithic; and
wherein said dish-shaped reflectors are large paraboloidal reflectors, and a unit generator further comprises a ball field lens at the focus of the corresponding large paraboloidal reflector, which forms an image of said large paraboloidal reflector on a concave spherical shaped surface to illuminate a plurality of photovoltaic cells electrically connected in series to combine the electrical power produced by each cell into a total output of electricity from the unit generator, wherein the intensity of solar radiation across all of the photovoltaic cells is stabilized by the ball lens against pointing errors of the two-axis tracker.
2. A solar concentrator apparatus, comprising:
an array of solar reflectors each being adapted to concentrate solar radiation and focus solar radiation on a converter unit, and a two-axis tracker adapted to point said array of solar reflectors in a direction such that the array of solar reflectors are positioned to simultaneously receive solar radiation and focus the solar radiation of each solar reflector on an associated converter unit;
said reflectors are dish-shaped reflectors and are supported in a moveable spaceframe comprising a rigid, lightweight, open truss structure that extends in three dimensions and is constructed from struts joined at nodes, wherein the spaceframe comprises a rectangular framework of struts with diagonal braces, said spaceframe having nodes to hold individual dish-shaped solar reflectors, individual converter units, and mounting points for elevation bearings, the elevation bearings being supported by elevation nodes formed as part of the spaceframe, the converter units comprising unit generators, said spaceframe being moveable;
said struts of said spaceframe structure forming a plurality of unit reflector cells configured as right prisms with provision to support a unit generator near the focus of a corresponding dish-shaped reflector, wherein each said dish-shaped reflector is supported from lower nodes of a corresponding unit reflector cell and each said associated unit generator is supported from upper nodes of a corresponding unit reflector cell;
said spaceframe comprises a framework having two staggered rows of unit reflector cells, with the upper row of unit reflector cells set forward and the lower row of unit reflector cells positioned back, so that the front lower edge of the upper row coincides with the back upper edge of the lower row, and a common central horizontal structural member is provided in the framework extending the full length of the framework, the common structural member passing close to the center of gravity of the framework, the common structural member being coincident with the elevation axis;
the framework being completed by front stiffening members and by rear stiffening members between the upper row and the lower row, wherein the front stiffening members link upper front corners of the upper row and the lower row, and wherein the rear stiffening members link lower back corners of the upper row and the lower row, and wherein the front stiffening members and the rear stiffening members comprising perimeter stiffening struts in planes perpendicular to the upper row of unit reflector cells and the lower row of unit reflector cells to provide high stiffness against bending about the elevation axis;
the elevation axis having an elevation bearing supporting the framework at stiff elevation nodes formed at the intersection of corner struts of four inner unit reflector cells included in the upper row and the lower row of the unit reflector cells, so that the elevation axis connects to the spaceframe framework via two nodes on the central structural axis, the stiff elevation nodes and elevation bearing being located at narrow central cells in the upper row and the lower row of the unit reflector cells, wherein the framework is balanced about the elevation axis;
said two-axis tracker being configured to move said spaceframe structure in elevation by rotating said spaceframe about an elevation axis coincident with said elevation bearings and by rotating said spaceframe about an azimuth axis, the elevation bearing being supported by a central pedestal that turns in azimuth about a fixed vertical shaft anchored to the ground; and
a controller coupled to said tracker, said controller being operative to control the motion of the tracker so that the array of solar reflectors are oriented to the sun to focus solar radiation onto the converter units as the sun moves across the sky.
3. The solar concentrator apparatus according to claim 2, wherein:
said dish-shaped reflectors are large paraboloidal reflectors, and a unit generator further comprises a ball field lens at the focus of the corresponding large paraboloidal reflector, which forms an image of said large paraboloidal reflector on a concave spherical shaped surface to illuminate a plurality of photovoltaic cells electrically connected in series to combine the electrical power produced by each cell into a total output of electricity from the unit generator, wherein the intensity of solar radiation across all of the photovoltaic cells is stabilized by the ball lens against pointing errors of the two-axis tracker.
4. The solar concentrator apparatus according to claim 2, wherein an elevation drive is provided comprising an elevation arc attached to the framework, and an elevation drive chain securely attached to the elevation arc, wherein the elevation drive chain is driven by an electric motor.
5. The solar concentrator apparatus according to claim 4, wherein said central pedestal takes the form of a post inserted into an excavated hole backfilled with crushed rock.
6. The solar concentrator apparatus according to claim 2, wherein an azimuth drive is provided comprising a drive wheel attached to the central pedestal, and an azimuth drive chain securely attached to the azimuth drive Wheel, wherein the azimuth drive chain is driven by an electric motor.
7. The solar concentrator apparatus according to claim 6, wherein an elevation drive is provided comprising an elevation arc attached to the framework, and an elevation drive chain securely attached to the elevation arc, wherein the elevation drive chain is driven by an electric motor.
8. The solar concentrator apparatus according to claim 7, wherein said central pedestal takes the form of a triangular steel truss that extends into an excavated hole.
9. A solar concentrator apparatus, comprising:
a plurality of dish-shaped reflectors co-axially aligned in an array supported by a single moveable elevation spaceframe, said elevation spaceframe comprising a rigid, lightweight, open truss structure that extends in three dimensions and is constricted from struts joined at nodes forming a rectangular framework of struts with diagonal braces, said dish-shaped reflectors having a focus and being adapted to concentrate solar radiation, wherein the plurality of said dish-shaped reflectors each has a converter positioned at the focus of the dish-shaped reflector;
a two-axis tracker supporting said moveable frame, said two-axis tracker being adapted to point the moveable spaceframe in a direction such that the array of dish-shaped reflectors are positioned to receive solar radiation; and
a control device coupled to said two-axis tracker, said control device being operative to move the two-axis tracker so that the array of dish-shaped reflectors continue to receive solar radiation as the sun moves across the sky during a substantial portion of daylight hours;
wherein said converters are operative to generate electrical power when solar radiation is focused upon said converters by a corresponding dish-shaped reflector;
wherein a plurality of said struts of the elevation spaceframe form a plurality of unit reflector cells configured as right prisms with provision to support a unit generator near the focus of a corresponding dish-shaped reflector, wherein each said dish-shaped reflector is supported from lower nodes of a corresponding unit reflector cell and each associated unit generator is supported from upper nodes of a corresponding unit reflector cell;
wherein said elevation spaceframe has a plurality of unit reflector cells in an upper row and a plurality of unit reflector cells in a lower row, further comprising:
a central pedestal supporting the elevation spaceframe, wherein the lower row of the elevation spaceframe has a narrow central cell providing space for an elevation bearing and the pedestal, the elevation bearing having two ends, the two ends of the elevation bearing being supported by stiff elevation nodes, formed as an inherent part of the elevation spaceframe at the intersection of corner struts of the inner unit reflector cells in the lower row, the elevation bearing being placed at the center of gravity of the full elevation structure that turns about the elevation bearing on the central pedestal;
the central pedestal comprising a thrust bearing so that the central pedestal turns about an azimuth axis; and
said two-axis tracker having an azimuth drive for turning a portion of the central pedestal above the thrust bearing in order to rotate the elevation spaceframe about an azimuth axis, and having an elevation drive to rotate the elevation spaceframe about an elevation axis coincident with said elevation bearings; and
wherein said dish-shaped reflectors are large paraboloidal reflectors, and a unit generator further comprises a hall field lens at the focus of the corresponding large paraboloidal reflector, which forms an image of said large paraboloidal reflector on a concave spherical shaped surface to illuminate a plurality of photovoltaic cells electrically connected in series to combine the electrical power produced by each cell into a total output of electricity from the unit generator, wherein the intensity of solar radiation across all of the photovoltaic cells is stabilized by the ball lens against pointing errors of the two-axis tracker.
10. A solar concentrator apparatus comprising:
a plurality of dish-shaped reflectors co-axially aligned in an array supported by a single moveable elevation spaceframe, said elevation spaceframe comprising a rigid, lightweight, open truss structure that extends in three dimensions and is constructed from struts joined at nodes forming a rectangular framework of struts with diagonal braces, said dish-shaped reflectors having a focus and being adapted to concentrate solar radiation, wherein the plurality of said dish-shaped reflectors each has a converter positioned at the focus of the dish-shaped reflector;
a two-axis tracker supporting said moveable frame, said two-axis tracker being adapted to point the moveable spaceframe in a direction such that the array of dish-shaped reflectors are positioned to receive solar radiation;
a control device coupled to said two-axis tracker, said control device being operative to move the two-axis tracker so that the array of dish-shaped reflectors continue to receive solar radiation as the sun moves across the sky during a substantial portion of daylight hours; and,
wherein said converters are operative to generate electrical power when solar radiation is focused upon said converters by a corresponding dish-shaped reflector;
wherein a plurality of said struts of the elevation spaceframe form a plurality of unit revlector coils configured as right prisms with provision to support a unit generator near the focus of a corresponding dish-shaped reflector, wherein each said dish-shaped reflector is supported from lower nodes of a corresponding unit reflector cell and each associated unit generator is supported from upper nodes of a corresponding unit reflector cell;
wherein said elevation spaceframe has a plurality of unit reflector cells in an upper row and a plurality of unit reflector cells in a lower row, further comprising:
a central pedestal supporting the elevation spaceframe, wherein the lower row of the elevation spaceframe has a narrow central cell providing space for an elevation bearing and the pedestal, the elevation bearing having two ends, the two ends of the elevation bearing being supported by stiff elevation nodes, formed as an inherent part of the elevation spaceframe at the intersection of corner struts of the inner unit reflector cells in the lower row, the elevation bearing being placed at the center of gravity of the full elevation structure that turns about the elevation bearing on the central pedestal;
the central pedestal comprising a thrust bearing so that the central pedestal turns about an azimuth axis; and
said two-axis tracker having an azimuth drive for turning a portion of the central pedestal above the thrust bearing in order to rotate the elevation spaceframe about an azimuth axis, and having an elevation drive to rotate the elevation spaceframe about an elevation axis coincident with said elevation bearings;
wherein said dish-shaped reflectors are monolithic;
wherein said dish shaped reflection are substantially square, and said unit reflector cells are right prisms having a square cross section, each dish-shaped reflector having a dish axis passing through the center of the dish-shaped reflector, the upper prism face of each right prism unit reflector cell having a center that lies on the corresponding dish axis of the dish-shaped reflector supported in said unit reflector cell, and the lower prism face of each right prism unit reflector cell having a center that lies on the corresponding dish axis of the dish-shaped reflector supported in said unit reflector cell, wherein each dish-shaped reflector is supported from the corners of the lower prism face by a dish support structure, and a corresponding converter unit is centered on the dish axis and is supported from the corners of the upper prism face;
wherein each dish-shaped reflector corresponds to a plurality of photovoltaic cells which are configured to receive reflected solar energy from the dish-shaped reflector, wherein the photovoltaic cells are configured for converting solar energy into electricity;
wherein each dish-shaped reflector corresponds to a ball field lens which is configured to receive reflected solar energy from the dish-shaped reflector and direct the solar energy at the plurality of photovoltaic cells.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A pipeline-type analog-to-digital (AD) converter, comprising:
N number of stages cascade-connected; and
a digital correction circuit that receives digital signals outputted from the N number of stages and outputs a final digital signal, wherein an Mth stage in the N number of stages includes:
a sub AD converter AD-converting an input analog signal;
a sub digital-to-analog (DA) converter DA converting a digital signal outputted from the sub AD converter;
a differential amplifier circuit that includes a sample hold circuit and an operational amplifier, performs an sampling operation and a holding operation to obtain a difference between the input analog signal and an output signal of the sub DA converter, and amplifies the difference; and
a compensation circuit compensating a gain error of the operational amplifier in an operation of the differential amplifier circuit, the gain error being caused by parasitic capacitance between an input terminal and an output terminal of the operational amplifier, and wherein 1\u2266M<N.
2. The pipeline-type AD converter according to claim 1, wherein the compensation circuit compensates, in the operation of the differential amplifier circuit, an electric charge flowing into the parasitic capacitance between the input terminal and the output terminal of the operational amplifier from a capacitor of the sample hold circuit with respect to the capacitor.
3. The pipeline-type AD converter according to claim 1, the compensation circuit including:
a first circuit having:
a first switch selecting the input analog signal;
a second switch selecting a predetermined potential; and
a first compensation capacitor selectively receiving the input analog signal selected by the first switch and the predetermined potential selected by the second switch, one end of the first compensation capacitor being coupled to the input terminal of the operational amplifier; and
a second circuit having:
a third switch selecting the output signal of the sub DA converter;
a fourth switch selecting the predetermined potential; and
a second compensation capacitor selectively receiving the output signal selected by the third switch and the predetermined potential selected by the fourth switch, one end of the second capacitor being coupled to the input terminal of the operational amplifier.
4. The pipeline-type AD converter according to claim 3, wherein, in the compensation circuit, in the sampling operation of the sample hold circuit, the first switch selects the input analog signal to input the selected input analog signal to the first compensation capacitor, and the fourth switch selects the predetermined potential to input the selected predetermined potential to the second compensation capacitor, while, in the holding operation of the sample hold circuit, the second switch selects the predetermined potential to input the selected predetermined potential to the first compensation capacitor, and the third switch selects the output signal of the sub DA converter to input the selected output signal to the second compensation capacitor.
5. A pipeline-type analog-to-digital (AD) converter, comprising:
N number of stages cascade-connected; and
a digital correction circuit that receives digital signals outputted from the N number of stages and outputs a final digital signal, wherein an Mth stage and an M+1th stage in the N number of stages commonly use an operational amplifier in a time-sharing manner, wherein the Mth stage includes:
a first sub AD converter AD-converting an input analog signal;
a first sub digital-to-analog (DA) converter DA converting a digital signal outputted from the first sub AD converter; and
a first differential amplifier circuit that includes a first sample hold circuit, performs an sampling operation and a holding operation to obtain a difference between the input analog signal and an output signal of the first sub DA converter, and amplifies the difference; and
a first compensation circuit compensating a gain error of the operational amplifier, if the first differential amplifier circuit uses the operational amplifier, the gain error being caused by parasitic capacitance between an input terminal and an output terminal of the operational amplifier; and
the M+1th stage includes:
a second sub AD converter AD-converting an analog signal outputted from the operational amplifier;
a second sub DA converter DA-converting a digital signal outputted from the second sub AD converter;
a second differential amplifier circuit that includes a second sample hold circuit, performs an sampling operation and a holding operation to obtain a difference between the analog signal outputted from the operational amplifier and an output signal of the second sub DA converter, and amplifies the difference; and
a second compensation circuit compensating a gain error of the operational amplifier, if the second differential amplifier circuit uses the operational amplifier, the gain error being caused by the parasitic capacitance between the input terminal and the output terminal of the operational amplifier, and
wherein 1\u2266M<N.
6. The pipeline-type AD converter according to claim 5, wherein the operational amplifier is of a fully-differential type.