Solar power generation system based on space

Abstract

Implementations of the disclosed subject matter provide a system having an artificial light source disposed at a distance from the earth or other celestial body, wherein the artificial light source is configured to project one or more light beams onto the earth or other celestial body. The system may include a photovoltaic array disposed in any one area on the earth or other celestial body having a dimension of 200 m to 20 km or greater, the photovoltaic array configured to receive the projected one or more light beams, and configured to convert the received one or more light beams to electricity.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. application serial number 63 / 368,534, filed on July 15, 2022, the disclosure of which is incorporated herein by reference in its entirety. Background Art

[0003] Space-based solar power (SSP) systems include microwave-based systems and optical systems. Microwave-based systems typically require large filled apertures in space, and large rectenna apertures on the ground. Such systems typically have safety issues based on allowable microwave exposure limits. Optical SSP systems have attempted to address the issues of microwave-based SSP systems. Previously proposed optical SSP systems have potentially higher safety strength limits than microwave-based SSP systems. However, such previously proposed optical SSP systems typically use small ground apertures that require high beam quality laser sources, and use terrestrial solar cell arrays made of materials that are different from most solar cells used for large-scale terrestrial power generation. Summary of the invention

[0004] Implementations of the disclosed subject matter provide a system having an artificial light source disposed at a distance from the earth or other celestial body, wherein the artificial light source is configured to project one or more light beams onto the earth or other celestial body. The system may include a photovoltaic array disposed in an area of ​​200 m to 20 km or more in any one dimension on the earth or other celestial body, the photovoltaic array being configured to receive the projected one or more light beams and being configured to convert the received one or more light beams into electricity.

[0005] Implementations of the disclosed subject matter provide a system that may have at least one satellite, the system including an artificial light source configured to project light onto the Earth or other celestial body, and a photovoltaic array configured to power the artificial light source. In the system, there may be an unconditional direct electrical connection between one or more units of the photovoltaic array and the artificial light source. At least a portion of the photovoltaic array may match the effective load impedance of the artificial light source.

[0006] Implementations of the disclosed subject matter provide a system having at least one satellite, the system may include: an artificial light source configured to project one or more light beams onto the Earth or other celestial body; a photovoltaic array electrically coupled to the artificial light source and configured to supply power to the artificial light source; and a heat sink thermally coupled to the artificial light source and configured to dissipate heat generated by the artificial light source when the one or more light beams are projected. The system may include a terrestrial photovoltaic array arranged in an area of ​​the Earth or other celestial body having a size of 200m to 20km or more in any one dimension, the terrestrial photovoltaic array configured to receive the projected one or more light beams, and configured to convert the received one or more light beams into electricity.

[0007] Additional features, advantages and implementations of the disclosed subject matter may be set forth or apparent by considering the following detailed description, drawings and claims. In addition, it should be understood that the foregoing summary and the following detailed description are illustrative and are intended to provide further explanation without limiting the scope of the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The accompanying drawings, which are included to provide a further understanding of the disclosed subject matter, are incorporated into and constitute a part of this specification. The accompanying drawings also illustrate implementations of the disclosed subject matter and, together with the detailed description, serve to explain the principles of implementations of the disclosed subject matter. No attempt is made to show structural details in more detail than is necessary for a basic understanding of the disclosed subject matter and the various ways in which it can be implemented.

[0009] Figure 1 An example space-based solar power (SSP) system in accordance with implementations of the disclosed subject matter is shown.

[0010] Figure 2A-2B An example SSP satellite and terrestrial photovoltaic array are shown in accordance with implementations of the disclosed subject matter.

[0011] Figure 3 Example current-voltage curves in arbitrary current and voltage units for a solar cell and a laser diode according to implementations of the disclosed subject matter are shown. DETAILED DESCRIPTION

[0012] Implementations disclosed herein relate to systems, devices, and techniques for providing space-based solar power (SSP). Previous attempts to design or construct SSP systems generally fall into two categories: microwave-based systems and optical / infrared systems. Microwave systems have attracted the most attention due to their perceived lower technical requirements. For example, there have been a number of laboratory demonstrations of microwave amplifiers approaching the required efficiency and power density (typically at least 70% and 1000 W / kg or more), as well as rectenna electronics with the required efficiency (typically at least 70%). Based on these experiments and real-world terrestrial experiments sending multiple kW of power over distances of multiple kilometers (km), microwave-based SSP is classically considered to be more mature. However, the field is constrained by various other limitations, including the large (spanning multiple kilometers) filled apertures required to assemble components in space, large rectenna apertures on the ground, and the low permissible microwave exposure limits (typically in the tens of W / m 2 or smaller). Microwave-based solutions also have problems common to all existing SSP approaches, including launch costs, in-space assembly costs and difficulties, electronics expenses, etc.

[0013] Some optical SSP approaches attempt to address these issues. The shorter wavelengths used by these techniques, compared to the multi-kilometer scales required for microwave-based approaches, allow for smaller apertures in space of 1 m or less, which would enable a constellation of independently launched, deployed, and operated satellites. Such satellites would be small enough to eliminate in-space assembly of large structures. Optical (particularly near-infrared (IR)) lasers have potentially higher safety intensity limits, but they are still less than ~1 kW / m 2 This limits the usefulness of small earth apertures allowed by laser sources with good beam quality (for extended exposures). That is, such sources are less than ~1 kW / m 2 The safe intensity limits are for laser sources used as point sources, such as those used in existing optical SSP methods. In contrast, the laser sources used in implementations of the disclosed subject matter may be extended sources (e.g., visual extended sources), where the intensity (power per unit area) can safely exceed ~1 kW / m 2 The artificial light sources used in implementations of the disclosed subject matter can be extended over a larger area of ​​the sky (e.g., in multiple satellites), which can safely provide light without damaging human or animal eyes. The beam quality of such existing optical SSP methods can be based on the beam parameter product (BPP) value, beam divergence, etc. A low value of BPP means high beam quality.

[0014] Conventional optical SSP systems proposed use diode-pumped solid-state lasers (DPSSLs) or other diode-pumped lasers (e.g., diode-pumped alkali lasers) to provide high total power (e.g., using coherent or incoherent combined arrays) and relatively good beam quality. While these systems provide fairly high efficiency and good beam quality, their wavelengths (typically greater than 1 μm for DPSSLs) require the use of expensive photovoltaic receiver units, such as those with expensive III-V materials. Thus, in these past proposals, ground efficiency and economic considerations tended to push optical solutions toward small receiver areas. While these small areas reduce the cost of the receiver arrays, they require high (unsafe) intensities to obtain relatively large amounts of power, and require extremely precise pointing and tracking to ensure that the delivered beam remains on the small receiver. The relatively low efficiency of DPSSLs, the expensive receivers, the need for precise pointing, and the requirement for high intensities render conventional optical SSP technologies both technically and economically unacceptable.

[0015] Existing systems have attempted to exploit the relatively short wavelength of the laser to achieve a small spot size on Earth with a small aperture in space. Such arrangements are advantageous because they can minimize the cost of the receiver on the ground and the cost of the telescope in space. However, in order to obtain large amounts of power, such systems have faced an unavoidable trade-off - significantly exceeding safe intensity on the ground, or using much larger receivers on the ground. To date, neither option has been feasible. As implemented in the implementations of the disclosed subject matter discussed throughout, if one chooses to maintain safe intensity, the minimum receiver size obtained for economically favorable large-scale power levels becomes large enough where the transmission aperture in space becomes very small, or more importantly, where spatial coherence (effectively, laser beam quality) becomes less important.

[0016] Typically, these existing systems rely on diode-pumped optical fibers or diode-pumped bulk lasers that convert the efficient but spatially incoherent light emitted by a large array of laser diodes (whether fiber-coupled or not) into a much smaller number of highly coherent beams for projection onto the earth. The use of such pumping unfortunately results in laser wavelengths that are typically greater than 1 μm, which means that relatively exotic materials must be used for solar cell receiver arrays and photovoltaic arrays cannot be used in existing solar fields. Specifically, such receivers cannot typically be based on silicon, copper indium gallium diselenide (CIGS), cadmium telluride (CdTe), and perovskites, or other common low-cost receiver materials and structures. Other existing diode-pumped systems (e.g., diode-pumped alkaline laser (DPAL) systems) use shorter wavelengths, but have efficiency losses and cost and complexity issues similar to the aforementioned diode-pumped systems and / or diode-pumped solid-state systems.

[0017] Implementations of the disclosed subject matter can use fiber-coupled diode laser arrays because the importance of spatial coherence is reduced when a sufficiently large ground receiver is used. This arrangement can increase electro-optical efficiency by avoiding intermediate light-to-light laser conversion, and can reduce system mass. Implementations of the disclosed subject matter can use larger receiver apertures of terrestrial photovoltaic arrays, which can be provided by solar fields and receivers of considerable size. Implementations of the disclosed subject matter can use artificial light sources that output light beams with low coherence in space, such as by using incoherently combined diode lasers coupled directly to fibers. The disclosed subject matter can improve system efficiency, thereby reducing thermal requirements and allowing lower temperature operation. The ability to operate at lower temperatures can further improve the efficiency of artificial light sources (e.g., laser efficiency). Implementations of the disclosed subject matter can shift the wavelength of the artificial light source to an area that can easily pass through the atmosphere and can be converted with high efficiency by conventional solar arrays.

[0018] Figure 1 A schematic representation of a space-based solar power generation system 10 according to an implementation of the disclosed subject matter is shown. One or more photovoltaic (PV) arrays 110 may be placed in orbit as part of a satellite 200. The PV array 110 may collect solar energy, convert the collected solar energy into electrical energy, and store and / or transmit the energy to a receiver 130 on Earth or another celestial body. The satellite 200 may include an artificial light source (e.g., a diode laser 120) that may be powered by electrical energy from the PV array 110. The diode laser 120 may be coupled to the PV array 110 and may be used to transmit the received and / or stored power to a terrestrial photovoltaic array (e.g., a receiver 130) via one or more light beams 300. In some implementations, the diode laser 120 may be directly coupled to the PV array 110, as discussed in detail below. The size of the receiver 130 may be configured to allow a wide or incoherent beam pattern from the diode laser 120. The receiver 130 may use a conventional PV array commonly found in modern solar fields. The wavelength of the one or more light beams 300 output from the laser diode 120 can be selected to match the most efficient absorption wavelength of the receiver 130, as disclosed in further detail below. The receiver 130 can convert the received laser light from the one or more light beams 300 into electricity for use and / or storage, such as via a conventional power grid 140, a battery-based or similar storage system 150, etc. Figure 1 One satellite 200 is shown in FIG. 1 , but there may be multiple satellites 200 that can output beams 300 to one or more receivers 130 .

[0019] The efficiency of the diode laser 120 may be inversely proportional to the junction temperature. In laboratory testing, a laser diode with a room temperature efficiency of 60-65% may approach 75-85% efficiency when cooled to temperatures below 0° C. Some laboratory tests have produced 85% diode efficiency at -40° C, while other laboratory tests have established >70% efficiency at ˜0° C.

[0020] The negative correlation between efficiency and temperature has little impact on typical laser diode systems because the energy cost of refrigeration and / or cooling of the laser diode is greater than the energy savings of improved efficiency. However, this negative correlation between efficiency and temperature becomes important when operating laser diodes in space applications, such as the implementations disclosed herein. In space, the background temperature is extremely low when heat input from the sun, the earth, and / or other celestial bodies is properly considered. These heat inputs for SSPs in accordance with the disclosed subject matter can be addressed by shielding, blocking, and / or high emissivity / low absorptivity coatings or materials. Therefore, any low temperature that is effective in space may only be limited by sunlight exposure, materials, and heat flux per unit area. For example, materials can be selected to achieve a sufficiently low mass that is economically feasible. That is, if a low-cost, high-conductivity material is selected, there may be more heat sink plates per unit of waste heat, which allows the diode laser 120 to operate at a cooler temperature. The lighter the heat sink plate (e.g., the higher the conductivity per unit mass of the heat sink), the cooler the laser (e.g., the diode laser 120) can be. This may reduce the required power and size of a PV array (eg, PV array 110 ).

[0021] Therefore, when using diode lasers in space, especially for power beam applications, this temperature-dependent efficiency effect can be exploited, together with low mass, low temperature heat sinks and modern low absorption and / or high emissivity coatings, to achieve significantly higher efficiencies than normal laser diodes. Although this effect is generally known for terrestrial laser applications, it has not been applied to space applications, especially not for power beam applications in space using diode lasers, to date.

[0022] Near-infrared (NIR) lasers can have high efficiency and can be used for power beam applications because existing solar cell technology can be used as a receiver. For typical existing mass-produced solar cell technologies, including III-V cells (such as gallium arsenide (GaAs) cells), cadmium telluride (CdTe) cells, copper indium gallium diselenide (CIGS) cells, and silicon cells, NIR wavelengths can maximize conversion efficiency. This is because the photon energy is close to but not lower than the band gap energy of those materials. This effect can improve and / or maximize quantum efficiency (the ratio of electrons generated to photons absorbed), and can also improve and / or maximize power efficiency because any energy in the photon greater than the band gap energy is wasted as heat.

[0023] By selecting an artificial illumination source (e.g., a laser) that efficiently produces a wavelength close to the bandgap of the materials of a conventional solar array, the overall system efficiency can be increased and / or maximized. Because the receiver technology of the disclosed subject matter implementation uses existing, mass-produced, large-area solar cells / modules / fields, the need to reduce system costs with narrow beams is reduced and / or eliminated. The benefit of this combination is twofold. While diode-pumped lasers have better beam quality than direct diode lasers, their longer wavelengths require special receiver unit technology (e.g., solar arrays made of non-traditional materials) and their overall transmission efficiency is lower. Therefore, the implementations disclosed herein can use diode lasers as artificial light sources without using intermediate steps to pump different materials.

[0024] Implementations of the disclosed subject matter can utilize diode lasers directly by incoherently combining the light from multiple diodes into a delivery fiber. The beams from the lasers and delivery fiber can be combined and then directed through optics or simply directed to a receiver on the ground. Figure 2A-2B As discussed, this arrangement can achieve improvements in bundled solar power generation.

[0025] Laser diodes typically require driver electronics to prevent overcurrent damage. This is because, as diode devices, their current-voltage curve exhibits a virtually flat portion with a small upward slope until a threshold voltage / current, at which point the slope of the current / voltage curve rises sharply. Figure 3 As shown, the current-voltage curve of a diode laser has a low slope (ie, is effectively flat) until a threshold point (eg, Figure 30.8 arbitrary voltage unit point shown), at the threshold point, the current / voltage curve rises with increasing slope. The slope depends on the temperature of the device, manufacturing variations, device life and other factors. Due to the steepness of the curve, low source impedance, current controlled power supplies can be used, but such power supplies are generally complex, bulky and / or expensive and reduce overall efficiency.

[0026] Similarly, the current-voltage curve of a solar cell is typically nearly flat (i.e., constant current as the voltage increases, starting from the short-circuit current) until a certain point, at which the current drops rapidly to zero as the voltage reaches the open-circuit voltage of the cell. Figure 3 As shown in , the current-voltage curve of a solar cell can be almost flat until a threshold point (e.g., Figure 3 0.85 arbitrary voltage unit points shown in ), where the voltage / current has a significant decrease (i.e., the slope gradually decreases to zero). In normal operation, the maximum power point tracker (MPPT) circuit is used to adjust the effective load impedance to operate the power supply at the inflection point of the curve of the solar cell (e.g., as Figure 3 ) to extract maximum power.

[0027] In the case of lasers and solar cells, the power electronics typically take the form of high frequency switching DC-DC converters and sometimes include smoothing and / or linear stages to provide precise current control or current limiting. Implementations of the disclosed subject matter can eliminate both sets of power electronics (i.e., those for the lasers and solar cells) when operating the solar cells and diode lasers in an efficient constant manner for beamed space solar power generation.

[0028] By matching a series-parallel arrangement of a large number of solar cells and laser diodes, implementations of the disclosed subject matter can match the current-voltage (IV) curves of the two devices. That is, when the IV curves of the solar cell and the diode laser are properly matched, the near-constant current output of the solar cell can provide current limiting for safe laser diode operation, and the threshold voltage and / or diode-like impedance characteristics of the laser diode can be used to extract the maximum possible power from the solar cell.

[0029] The implementation disclosed herein can operate without intervening power electronics by matching the IV curves of the two devices and by matching the series-parallel arrangement of a large number of solar cells and laser diodes as described above, which is usually required for stability. That is, by using such matching, the implementation of the disclosed subject matter does not use traditional high-bandwidth electronics (e.g., traditional power electronics). In some implementations, extremely low bandwidth shunts and / or fixed shunt (e.g., bypass) current control can be used to adapt to manufacturing variations of the device and / or to the start of designed overcurrent operations, thereby addressing aging. The use of such low bandwidth or fixed shunts (bypasses) is not for stability or safety, but can be used to maximize output power over time. That is, a conservative fixed set point can be used, and the fixed set point can be stable over time, but slightly less power can be output.

[0030] Figure 2A-2B An implementation according to the disclosed subject matter is shown. Figure 1 1 and 130. Satellite 200 may have multiple modules 202, which may include one or more PV arrays 110, one or more laser diode modules 120, one or more heat sink panels 210, and / or one or more output optical fibers 215. One or more PV arrays 110 may convert sunlight into electrical power. One or more laser diode modules 120 may convert electrical power into optical power and transmit the optical power to an optical fiber. For example, Figure 2A As shown, the output of one or more laser diode modules 120 can be provided to output optical fibers 215, and one or more of the output optical fibers 215 can be combined using a fiber combiner 220 to form one or more delivery optical fibers 230. Alternatively, the output from one or more laser diode modules 120 can be provided directly to a delivery telescope 240 for delivery to one or more receivers 130 on Earth and / or another celestial body. In another example, Figure 2B It is shown that the output of one or more laser diode modules 120 can be provided to a delivery fiber 216 , where the beams from the delivery fiber can be combined by a free space beam combiner 217 and provided to a delivery telescope 240 .

[0031] like Figure 2A-2B As shown, one or more heat sink plates 210 may be used to remove waste heat from the laser diode module 120. One or more transmission telescopes 240 may project the optical power generated by the laser diode module 120 with a divergence that matches one or more terrestrial receivers 130. The laser diode module 120 and the receiver 130 may be IV curve matched to improve power transfer efficiency. Figure 2AAs shown, a fiber combiner 220 can be used to combine one or more output fibers 215 from a laser module 120 into fewer delivery fibers 230 before transmitting power to one or more delivery telescopes 240 for transmission to one or more terrestrial receivers 30. Figure 2B As shown, the free space beam combiner 217 can combine the beams received from the delivery optical fiber 216 and provide the combined beams to one or more delivery telescopes 240 for transmission to one or more ground receivers 30. Figure 2A-2B As shown, coarse aiming scope 250 can be used to steer output beams 300 of delivery telescope 240 toward the Earth and / or other celestial bodies and provide coarse aiming of these beams to one or more receivers 130, which can be part of a solar field on the ground and / or on another celestial body.

[0032] As described above, the implementations disclosed herein benefit from developments and insights that are not available or fully developed in existing SSP systems. The receiving terrestrial arrays used in the implementations of the disclosed subject matter do not have to be very small, but can be on the order of the size of modern solar fields. The use of large receiving spot sizes (e.g., the area of ​​the receiver of the solar field) can allow the energy involved to be particularly safe compared to traditional methods. The large receiving spot size can allow relatively cheap but effective incoherent combination of diode laser arrays to transmit orbital power to terrestrial receivers. The artificial light sources used in the implementations of the disclosed subject matter can be extended over a large area of ​​the sky (e.g., in multiple satellites), which can safely provide light to large receiving spot sizes (e.g., terrestrial receivers) without damaging human or animal eyes. In some implementations, existing solar fields can be used because efficient NIR wavelength lasers as described in the full text in conjunction with the disclosed implementations can be used. Illuminating existing solar fields with conversion to matching wavelengths can result in increased efficiency, such as wavelengths that traditional solar cells can effectively receive and convert to electricity, which is not possible in existing systems. Using orbiting solar panels to operate laser diodes can be self-current limiting and can eliminate the need for most power electronics, further reducing system complexity and expense without sacrificing efficiency.

[0033] like Figure 1-3 As shown, the implementation of the disclosed subject matter provides a system (e.g., Figure 1 The system 10 shown in the figure may have an artificial light source (e.g., Figure 1-2B The diode laser 120 shown in FIG. 1 ) wherein the artificial light source is configured to direct one or more light beams (e.g., Figure 1 The system may include a terrestrial photovoltaic array (e.g., Figure 1-2B The terrestrial photovoltaic array is arranged in any one dimension and / or in an area with a diameter of 200m to 20km or more on the earth or other celestial bodies, and is configured to receive one or more projected light beams and to convert the received one or more light beams into electricity. For example, a terrestrial photovoltaic array (e.g., Figure 1-2B The receivers 130 shown in FIG. 1 ) may be arranged in an area greater than 20 km in any one dimension, such as 21-30 km, 31-50 km, 51-70 km, 71-100 km or greater in any one dimension.

[0034] Artificial light sources can be Figure 1-2B The diode laser 120 shown. The peak wavelength range of one or more beams of the artificial light source can be 750nm to 2000nm. For example, the artificial light source of the system can have a peak wavelength range of 800-1020nm. In another example, the artificial light source of the system can have a peak wavelength range of 780-850nm. In yet another example, the artificial light source for the system can have a peak wavelength range of 940-1020nm. Example peak wavelength ranges of artificial light sources can have wavelengths of 808nm, 915nm and / or 976nm. In some implementations, the minimum beam parameter product (BPP) of the artificial light source can be greater than 10mm-mrad. The BPP can be the product of the beam radius (measured at the beam waist) and the beam divergence half angle. In some implementations, the artificial light source can have a range of 10-100mm-mrad.

[0035] The artificial light source and the peak wavelength range can be selected based on the efficiency range of the terrestrial photovoltaic array. The terrestrial photovoltaic array can be Figure 1-2B Terrestrial receiver 130 is shown. For example, the terrestrial photovoltaic array can be formed of silicon, gallium arsenide (GaAs), indium gallium arsenide (InGaAs), aluminum gallium arsenide (AlGaAs), copper indium gallium diselenide (CIGS), cadmium telluride (CdTe), and perovskite and / or other suitable materials to convert light into electricity. Based on the efficiency of the one or more materials forming the terrestrial photovoltaic array, an artificial light source having a peak wavelength range that matches the efficiency of the one or more materials of the terrestrial photovoltaic array can be selected. That is, the band gap of the material forming the terrestrial photovoltaic array can match the wavelength range of light that the artificial light source is configured to output, the wavelength range of light being no longer than the wavelength range of light corresponding to the band gap of the material of the terrestrial photovoltaic array, as discussed in detail above.

[0036] The artificial light source can be a plurality of lasers, which can be laser diodes, fiber lasers, diode-pumped solid-state lasers, etc. In some implementations, the lasers of the artificial light source can be multimode and can have less coherence than single-mode lasers. Coherent light is light having photons oscillating at the same frequency and having in-phase wavelengths. In contrast, the photons of incoherent light oscillate at different frequencies, and their wavelengths are out of phase with each other. The light beam of an artificial light source having a multimode laser can be less coherent than, for example, a coherent light beam from a single-mode laser.

[0037] In some implementations, the artificial light source can include multiple modules, where each module includes multiple laser diodes coupled to a delivery fiber. For example, the module can be Figure 2A-2B The laser diode module 120 is shown. One or more modules (e.g., Figure 2A-2B The laser module 120 shown in FIG. 1 ) can be configured to operate at a temperature of 210K to 315K.

[0038] The delivery fibers 215 may be coupled to the laser diode modules 120. One or more delivery fibers 215 from multiple modules 120 may be combined into a free-space beam that forms one or more beams (e.g., Figure 2A-2B For example, Figure 2A As shown, the output fibers 215 from the laser diode modules 120 can be combined by a fiber combiner 220, which can be coupled to a delivery fiber 230. In another example, as shown in FIG. Figure 2B As shown, the delivery fibers 216 from the laser diode modules 120 can have output beams that can be combined in free space by the free space beam combiner 217. Figure 2A-2B Beam combining arrangements other than those shown in , such as using polarization beam combining, other spatial combining, or spectral beam combining in one or more steps using gratings, dichroic mirrors, and / or other frequency selective elements.

[0039] Light from multiple sources can be combined coherently or incoherently. When the combination of light is coherent, the combined light can have photons oscillating at the same frequency and having waveforms that are in phase. When the light is combined incoherently, the combined light can have photons oscillating at different frequencies and having waveforms that are out of phase with each other.

[0040] exist Figure 2A In FIG. 1 , a delivery optical fiber 230 can be coupled to a plurality of delivery telescopes 240. Figure 2B In, the output of the free space beam combiner 217 can be provided to the delivery telescope 240. Figure 2A-2B, the light beam output from the delivery telescope 240 may be reflected by the mirror 250 to form the output light beam 300. In some implementations, when a multi-mode diode laser is used as an artificial light source, the light beam projected by the artificial light source may have reduced coherence.

[0041] The output beams can be directed to a terrestrial photovoltaic array (eg, receiver 130 ) disposed in an area on the Earth or another celestial body. In some implementations, the terrestrial photovoltaic array can be part of a solar field that can receive one or more output beams 300 .

[0042] like Figure 1-2B As shown, the system may include a satellite having an artificial light source (e.g., a diode laser 120), a photovoltaic array (e.g., PV array 110) electrically coupled to the artificial light source and configured to power the artificial light source, and at least one heat sink plate (e.g., heat sink plate 210). The photovoltaic array of the satellite may be formed of silicon, gallium arsenide (GaAs), indium gallium arsenide (InGaAs), aluminum gallium arsenide (AlGaAs), copper indium gallium diselenide (CIGS), cadmium telluride (CdTe), and perovskite and / or other suitable materials or combinations of these materials in a multi-junction cell to convert light into electricity.

[0043] The size of the satellite can be less than 1000m, less than 1200m, less than 1500m, less than 1800m, less than 2000m, and / or any other suitable distance in any direction. The artificial light source can be thermally coupled to at least one radiator plate, wherein when the artificial light source is working, the radiator plate dissipates heat from the artificial light source. That is, at least one radiator plate can be configured to dissipate heat generated by the artificial light source into space. In some implementations, one or more of these modules can be distributed on at least one radiator plate.

[0044] In some implementations, at least one heat sink plate can be configured to increase the efficiency of the artificial light source and / or increase the output power of the artificial light source. Since the heat sink plate can be thermally coupled to the artificial light source to dissipate heat generated by the artificial light source during operation. By dissipating heat, the heat sink plate can increase the operating efficiency of the artificial light source and / or can increase the optical power of the light output by the artificial light source.

[0045] The selection of the size of the at least one radiator plate and the mass of the at least one radiator plate reduces the amount of artificial light source electrical power of the system for a given light output power. The selection of the size and / or mass of the at least one radiator plate can be based on the total mass of the satellite. Such selection can reduce the size of the satellite's photovoltaic array and can increase the size of the radiator plate.

[0046] The relationship of the mass of at least one radiator plate and the temperature of at least one radiator plate to the efficiency of the rest of the satellite can reduce the combined total mass of the satellite's photovoltaic array and at least one radiator plate. That is, the radiator plate can be configured to radiate power left over from the inefficiency of the artificial light source. The selected mass of the radiator plate per unit output power and the mass of the satellite's photovoltaic array per unit output power can allow the total mass of the satellite including the radiator plate, photovoltaic array and artificial light source to be smaller and / or more efficient. That is, the configuration and temperature of the radiator plate can allow the total mass of the satellite to be smaller and / or more efficient.

[0047] Implementations of the disclosed subject matter provide a method of providing a system that can have a satellite (e.g., Figure 1-2B 200) shown in FIG. 1 , the satellite includes an artificial light source (e.g., Figure 1-2B ), and a photovoltaic array configured to power an artificial light source (e.g., Figure 1 PV array 110 shown in FIG. 1 ). The artificial light source may include a plurality of delivery optical fibers (e.g., Figure 2A The delivery optical fiber 215 and / or Figure 2B In the system, there may be an unconditioned direct electrical connection between one or more units of a photovoltaic array (e.g., PV array 110) and an artificial light source (e.g., laser diode 120).

[0048] Maximum power point trackers (MPPTs) for solar arrays and power supplies for laser sources are typically impedance modulators, and the effective load (for MPPT) or source impedance (for example, for laser diode drivers) is adjusted by switching power supplies or similar devices. In some implementations of the disclosed subject matter, there are no active components (e.g., such as switching power supplies) between the satellite's photovoltaic array and the artificial light source. The direct electrical connection can be a broadband splitter and / or a fixed splitter (e.g., bypass), as discussed in detail above. In some implementations, active power electronics can be used between the satellite's photovoltaic array and the artificial light source.

[0049] At least a portion of the photovoltaic array can be matched to the effective load impedance of the artificial light source. For example, the source impedance curve of the series-parallel arrangement of the satellite's photovoltaic array can be matched to the load impedance curve of the artificial light source, as discussed in detail above. In some implementations, the matching can use the current output of the satellite's photovoltaic array to provide current limiting for the artificial light source. In some implementations, the matching uses the current-voltage response of the artificial light source to extract maximum power from the photovoltaic array, such as Figure 3shown and discussed in detail above.

[0050] For the purpose of illustration, the foregoing description has been described with reference to specific implementations. However, the above illustrative discussion is not intended to be exhaustive or limit the implementations of the disclosed subject matter to the precise forms disclosed. In view of the above teachings, many modifications and variations are possible. These implementations are selected and described in order to explain the principles of the implementations of the disclosed subject matter and their practical applications, so that other persons skilled in the art can utilize these implementations and various implementations with various modifications that may be suitable for the intended specific use.

Claims

1. A system, comprising: an artificial light source configured to be arranged at a distance from the earth or other celestial body, wherein the artificial light source is configured to project one or more light beams onto the earth or other celestial body; and A terrestrial photovoltaic array is arranged in an area of ​​200m to 20km or more in any dimension on the earth or other celestial body, and is configured to receive the projected one or more light beams and to convert the received one or more light beams into electricity. 2 . The system according to claim 1 , wherein the peak wavelength of the one or more light beams of the artificial light source is in the range of 750 nm to 2000 nm.

3. The system of claim 1, wherein a peak wavelength range of the one or more light beams of the artificial light source is selected based on an efficiency range of the terrestrial photovoltaic array.

4. The system of claim 1, wherein the terrestrial photovoltaic array is formed of at least one selected from the group consisting of silicon, gallium arsenide (GaAs), indium gallium arsenide (InGaAs), aluminum gallium arsenide (AlGaAs), copper indium gallium diselenide (CIGS), cadmium telluride (CdTe), and perovskite.

5. The system of claim 1, wherein the artificial light source combines light from multiple sources to form the one or more projected light beams.

6. The system of claim 5, wherein the light from the plurality of sources is combined coherently or incoherently.

7. The system of claim 1, wherein the artificial light source comprises a plurality of lasers.

8. The system of claim 1, wherein the artificial light source comprises a plurality of modules, wherein each module comprises a plurality of laser diodes coupled to a delivery optical fiber.

9. The system of claim 8, wherein one or more of the delivery fibers from the plurality of modules are combined into a free-space beam that forms one or more beams projected from the system.

10. The system of claim 8, wherein the one or more modules are configured to operate at a temperature of 210K to 315K.

11. The system of claim 8, wherein the system comprises at least one satellite, the at least one satellite comprising at least one heat sink, wherein the one or more modules are distributed on the at least one heat sink.

12. The system of claim 11, wherein the size of the satellite is less than 2000m in any direction.

13. The system of claim 1, wherein the minimum beam parameter product (BPP) of the artificial light source is greater than 10 mm-mrad.

14. The system of claim 1, wherein the system further comprises: A satellite, the satellite comprising: The artificial light source; a photovoltaic array electrically coupled to the artificial light source and configured to supply power to the artificial light source; and At least one heat sink plate, wherein the at least one heat sink plate is configured to dissipate heat generated by the artificial light source into space.

15. The system of claim 14, wherein the at least one heat sink plate is configured to increase at least one selected from the group consisting of: efficiency of the artificial light source and output power of the artificial light source for a given electrical power.

16. The system of claim 14, wherein selection of the size and mass of the at least one heat sink plate reduces the amount of electrical power used by the artificial light source of the system for a given light output power.

17. The system of claim 16, wherein selection of at least one of the size and the mass of the at least one heat sink plate is based on an overall mass of the system.

18. The system of claim 17, wherein the selecting reduces the size of the photovoltaic array and increases the size of the heat sink plate.

19. The system of claim 16, wherein the mass of the at least one heat sink plate and the temperature of the at least one heat sink plate in relation to the efficiency of the rest of the system reduces the combined total mass of the photovoltaic array and the at least one heat sink plate.

20. The system of claim 1, wherein a bandgap of a material forming the terrestrial photovoltaic array matches a range of wavelengths of light that the artificial light source is configured to output, the wavelengths being no longer than a wavelength corresponding to the bandgap of the material of the terrestrial photovoltaic array.

21. A system, comprising: At least one satellite, the at least one satellite comprising: an artificial light source configured to project light onto the Earth or another celestial body; and a photovoltaic array configured to supply power to the artificial light source, wherein there is an unconditional direct electrical connection between one or more cells of the photovoltaic array and the artificial light source, and At least a portion of the photovoltaic array is matched with an effective load impedance of the artificial light source.

22. The system of claim 21, wherein the artificial light source comprises: At least one module, the at least one module comprising: a plurality of laser diodes; and A plurality of delivery optical fibers, wherein each delivery optical fiber is coupled to one or more of the plurality of laser diodes.

23. The system of claim 21, wherein matching the effective load impedance of the artificial light source to a photovoltaic array comprises matching a source impedance curve of a series-parallel arrangement of the photovoltaic array to a load impedance curve of the artificial light source.

24. The system of claim 21, wherein the matching uses a current output of the photovoltaic array to provide current limiting to the artificial light source.

25. The system of claim 21, wherein the matching uses a current-voltage response of the artificial light source to extract maximum power from the photovoltaic array.

26. The system of claim 21, wherein the direct electrical connection comprises at least one selected from the group consisting of: a broadband splitter and a fixed splitter.

27. A system, comprising: At least one satellite, the at least one satellite comprising: an artificial light source configured to project one or more light beams onto the Earth or other celestial body; a photovoltaic array electrically coupled to the artificial light source and configured to supply power to the artificial light source; and a heat sink plate thermally coupled to the artificial light source and configured to dissipate heat generated by the artificial light source when projecting the one or more light beams; and A terrestrial photovoltaic array is arranged in an area of ​​the earth or other celestial body with a size of 200m to 20km or more in any one dimension, and is configured to receive one or more projected light beams and to convert the received one or more light beams into electricity.

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