2012 · 23 citations · 4 references
Inductively-coupled Power DeliveryEngineeringEnergy ConversionPlanar InductorsPhotovoltaic DevicesPhotovoltaic SystemPower ElectronicsPhotovoltaicsElectronic DevicesThin-film Lc OscillatorsCharge ExtractionSolar Thermal EnergyPower Electronic DevicesSolar Energy UtilisationMaterials ScienceElectrical EngineeringEnergy HarvestingWireless Power TransmissionSolar PowerPatterned Planar InductorsEnergy EngineeringLow-power ElectronicsFlexible ElectronicsQuality FactorSelf-powered NanodevicesEnergy Conversion MaterialsSolar Cell Materials
This paper presents an energy-harvesting system consisting of amorphous-silicon (a-Si) solar cells and thin-film-transistor (TFT) power circuits on plastic. Along with patterned planar inductors, the TFTs realize an LC-oscillator that provides power inversion of the DC solar-module output, enabling a low-cost sheet for inductively-coupled wireless charging of devices. Despite the low performance of the TFTs (f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">t</sub> =1.3MHz at a voltage of 15V), the oscillator can operate above 2MHz by incorporating the device parasitics into the resonant tank. This enables increased quality factor for the planar inductors, improving the power-transfer efficiency and the power delivered. With 3cm-radius single- and double-layer inductors, the system achieves 22.6% and 31% power-transfer efficiency (approaching the analytically-predicted bound), while the power delivered is 20mW and 22mW.
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