Manufacturing of highly efficient photovoltaic systems is marching on. A Korean development sets a new benchmark not only in respect to the efficiency of the solar cell itself, but also “condenses” the sunlight, concentrates it. The result is an outstandingly power dense system designed to most advantageously harvest energy from a so far still sparsely used natural resource. Maxon Motor Australia supplies the motor drives for continuous tracking of the actual solar position.
Usually, today used photovoltaic modules are limited to the photoelectric conversion of sunlight into electrical energy. Korean scientists now found a way to not only considerably improve the solar cells’ efficiency, but also to focus the incident sunlight and to significantly boost overall efficiency.
Three novel elements contribute to the remarkable improvement in performance: The high-resolution, real-time tracking towards the sun, highly efficient focusing of the solar radiation prior its conversion into electrical energy, and high-concentrated, extremely efficient solar cells.
Solar tracking of the photovoltaic panels is accomplished with 2 axis real-time control powered by maxon DC motor drives (brushless EC-max 30 mm motors with planetary gearhead (gearbox) GP 42 C) with a resolution of 0.0025 mm. Only this highly accurate positioning system allows optimized optical focusing. For that purpose, every individual solar cell is equipped with photo-optic condenser based on a Fresnel lens of a size of approximately 250 x 250 mm.
It condenses the sunlight by a factor of 300 to 500. Eventually, below the condenser positioned high-concentration solar cells are capable to generate up to 37 watts of electric energy – this on a surface of just one square centimeter (±0.15 square inches) and an efficiency of approximately 37 up to 40%. When compared to regular cells, the improvement corresponding to an increase of about 300%.
The consistent implementation of optimized utilization of the incident solar radiation results in a system of highest power density. Thus permitting self-contained systems composed of 12 modules which require floor space of less than 20 m2 and possessing the capacity to deliver 3.2 kW/h of electrical energy. It is natural to use the most efficient DC motors with the most efficient solar systems.