Automatic positioner and control system for a motorized parabolic solar reflector

[摘要] ENGLISH ABSTRACT: Most rural African villages enjoy high levels of sunlight, but rolling out solarpower generation technology to tap into this renewable energy resource at remoterural sites in Africa pose a number of design challenges. To meet thesechallenges, a project has been initiated to design, build and test/evaluate aknock down 3 kW peak electrical stand-alone self-tracking dual-axis concentratingsolar power system.This study focusses on the mechatronic engineering aspects in the designand development of a dynamic mechatronic platform and digital electroniccontrol system for the stand-alone concentrating solar power system. Designspecifications require an accurate automatic positioner and control system fora motorized parabolic solar reflector with an optical solar harnessing capacityof 12 kWt at solar noon. It must be suitable for stand-alone rural power generation.This study presents a conceptual design and engineering prototypeof a balanced cantilever tilt-and-swing dual-axis slew drive actuation meansas mechatronic solar tracking mobility platform for a ∼12 m2 lightweightparabolic solar concentrator. Digital automation of the concentrated solarplatform is implemented using an industrial Siemens S7-1200 programmablelogic controller (PLC) with digital remote control interfacing, pulse width modulateddirect current driving, and electronic open loop/closed loop solar trackingcontrol. The design and prototype incorporates off-the-shelf componentsto support local manufacturing at reduced cost and generally meets the goalof delivering a dynamic mechatronic platform for a concentrating solar powersystem that is easy to transport, assemble and install at remote rural sitesin Africa. Real-time experiments, conducted in the summer of South Africa,validated and established the accuracy of the engineering prototype positioningsystem. It shows that the as-designed and -built continuous solar trackingperforms to an optical accuracy of better than 1.0◦ on both the azimuth andelevation tracking axes; and which is also in compliance with the pre-defineddesign specifications.Structural aspects of the prototype parabolic dish are evaluated and optimizedby other researchers while the Stirling and power handling units are underdevelopment in parallel projects. Ultimately, these joint research projectsaim to produce a locally manufactured knock down do-it-yourself concentratedsolar power generation kit, suitable for deployment into Africa.

[发布机构] Stellenbosch University