Simultaneous wireless data and power transfer for a 1-Gb/s GaAs VCSEL and photovoltaic link

We study the trade-off between energy harvesting and data communication for a two-meter wireless gallium-arsenide vertical-cavity surface-emitting laser and photovoltaic link. The use of orthogonal frequency-division multiplexing with adaptive bit and power loading results in a peak data rate of 1041 Mb/s at a bit-error ratio (BER) of 2.2\times 10^{-3} under short-circuit conditions. The receiver is shown to provide power harvesting with an efficiency of 41.7% under the irradiance of 0.3 W/cm2 and simultaneous data communication with a rate of 784 Mb/s at a BER of 2.8\times 10^{-3}. The experimental system is envisioned to become a paradigm for next-generation wireless backhaul communications and Internet-of-Things applications

0.5-Gb/s OFDM-Based Laser Data and Power Transfer Using a GaAs Photovoltaic Cell

In this letter, we demonstrate for the first time the additional capability of high-speed data communication for single-junction photovoltaic (PV) cells. A record 3-dB bandwidth of 24.5 MHz is reported for a gallium arsenide (GaAs) PV cell. The PV cell is shown to achieve a power efficiency of at least 42% when irradiance of 0.46 W/cm2 is received from 847-nm vertical-cavity surface-emitted laser. Optimized bit-and-power-loaded optical orthogonal frequency-division multiplexing (OFDM) is applied to use the communication bandwidth most efficiently. With this, a data rate of 0.5 Gb/s is achieved for a 2-m OFDM-based laser link. To the best of our knowledge, the reported data rates achieved with a GaAs PV cell as the detector are the highest for simultaneous optical wireless information and power transfer

Toward high-efficiency hybrid (electricity and heat) high concentration photovoltaic systems

Paper presented to the 3rd Southern African Solar Energy Conference, South Africa, 11-13 May, 2015.Photovoltaic power generation is a growing renewable primary energy source, expected to assume a major role as we strive toward fossil fuel free energy production. However, the rather low photovoltaic efficiencies limit the conversion of solar radiation into useful power output. Hybrid systems extend the functionality of concentrating photovoltaics (CPV) from simply generating electricity, to providing simultaneously electricity and heat. The utilization of otherwise wasted heat significantly enhances the overall system efficiency and boosts the economic value of the generated power output. The system presented in this lecture is the outcome of collaborative research in my research group, with the IBM research lab in Zurich and the Fraunhofer Institute for solar energy systems in Freiburg, Germany. It consists of a scalable hybrid photovoltaic-thermal receiver package, cooled with an integrated high performance microchannel heat sink we initially developed and optimized for the efficient cooling of electronics. The package can be operated at elevated temperatures due to its overall low thermal resistance between solar cell and coolant. The effect of the harvested elevated coolant temperature on the photovoltaic efficiency is investigated. The higher-level available heat can be suitable for sophisticated thermal applications such as space heating, desalination or cooling (polygeneration approaches). A total hybrid conversion efficiency of solar radiation into useful power of 60% has been realized. The exergy content of the overall output power was increased by 50% through the exergy content of the extracted heat.dc201

Photovoltaisches Halbleiterbauelement zur Konversion von Strahlungsleistung in elektrische Leistung, Verfahren zu dessen Herstellung und dessen Verwendung

The invention relates to a photovoltaic semiconductor component for converting monochromatic radiation power into electric power, comprising at least one front-side sub-cell which faces the radiation incident on the semiconductor component and a rear-side sub-cell which is made of interconnected semiconductor layers. The materials of the semiconductor layers and/or the layer thicknesses thereof are selected such that at least one sub-cell exhibits an increased photon absorption compared to the other sub-cells. The invention likewise relates to a method for producing said photovoltaic semiconductor components. The photovoltaic components are used as radiation receivers in optical power transmission for example for monitoring high-voltage lines, passive optical networks, the supply of energy to and in active implants, disturbance-free electromagnetic field measurement, lightning-protected monitoring of wind turbines, explosion-proof sensor systems in airplane tanks, wireless power transmission, galvanically isolated power supply for sensor systems in high-voltage environments, wireless charging of consumer electronics, and the supply of power to underwater observatories

Worldwide Energy Harvesting Potential of Hybrid CPV/PV Technology

Hybridization of multi-junction concentrator photovoltaics with single-junction flat plate solar cells (CPV/PV) can deliver the highest power output per module area of any PV technology. Conversion efficiencies up to 34.2% have been published under the AM1.5g spectrum at standard test conditions for the EyeCon module which combines Fresnel lenses and III-V four-junction solar cells with bifacial c-Si. We investigate here its energy yield and compare it to conventional CPV as well as flat plate PV. The advantage of the hybrid CPV/PV module is that it converts direct sunlight with the most advanced multi-junction cell technology, while accessing diffuse, lens-scattered and back side irradiance with a Si cell that also serves as the heat distributor for the concentrator cells. This article quantifies that hybrid bifacial CPV/PV modules are expected to generate a 25 - 35% higher energy yield with respect to their closest competitor in regions with a diffuse irradiance fraction around 50%. Additionally, the relative cost of electricity generated by hybrid CPV/PV technology was calculated worldwide under certain economic assumptions. Therefore, this article gives clear guidance towards establishing competitive business cases for the technology