System-on-Chip for Real-Time Satellite Photovoltaic Curves Telemetry

This paper presents a System-on-Chip design for real-time satellites photovoltaic curves telemetry. In these applications, the limitation of memory and communication bandwidth makes quite difficult to store and to transmit the whole characteristic current-voltage (I-V) curve of any solar section in real-time. The proposed solution is based on the real-time calculation of the equivalent single-diode model of the solar section. The single-diode model fits accurately the behavior of any solar panel, so once the parameters are calculated, saved, and transmitted, at any working conditions, that specific curve could be later reproduced. The system is based on a LEON3 32-bit microprocessor core implemented in a Field Programmable Gate Array. The LEON microprocessors were originally designed by the European Space Agency, Paris, France, to be used in space projects where high reliability is required. In addition, in order to design the system as simple and reliable as possible, from all the methods available in the literature to extract the five parameters of the equivalent model, the Oblique Asymptote Method has been chosen for its simplicity and precision. Finally, some experimental results are presented to demonstrate the accuracy of the final system.