On a New Parallel Tracking System for Accurate Orientation of Concentrated Solar Convertors

Abstract

The concentrated solar energy convertors (e.g. solar-thermal dish, concentrated photovoltaic) require high tracking accuracy to maintain low incidence angles of the solar ray in relation with the concentrator optical axis (e.g. tracking accuracy of 0.05°...0.1°). This functional requirement is currently ensured by the high performance dual-axis solar tracking systems, able to reach the imposed accuracy, including expensive rotary actuator solutions. This paper proposes a new high accuracy tracking system for diurnal orientation, integrating a 2 DOF parallel linkage driven by linear actuators, as a simple, accurate, and cost-effective solution. A kinematic and static approach used for optimisation of the driving programs of the two linear actuators is presented, following the requirements: a) ensure the imposed tracking accuracy and b) achieve advantageous transmitting angles and hence lowest driving forces. The performances of the system are analysed on large orientation strokes (over 130°); the results obtained confirm the viability of the new tracking system concept, with higher performances compared to other similar known solutions.