Photovoltaic Sub-Module With Optical Sensor for Angular Measurements of Incident Light

This paper presents a photovoltaic (PV) sub-module with an optical sensor for angular measurements of incident light. The optical sensor is a CMOS microdevice for accurate tracking of the solar incident angle for application on PV systems. This microdevice was designed in 0.7- ${\mu }\text{m}$ CMOS and is composed by a matrix of photodiodes and the respective read-out circuits. A set of microstructures on metal with the widths of 5 and 10 $ {\mu }\text{m}$ was fabricated on the top of the photodiodes to allow the measuring of angles on a wide range of illuminations and for calibration purposes. The measurements done in the laboratory and in real-field open environments confirmed the suitability to track with good precision the maximum sun’s incident angle in the range [0°, 180°], only limited by the servomotor to rotate the system. This PV sub-module measures 12 cm $\times10$ cm $\times4$ cm and presents a total power consumption of 265 mW, when supplied by 5 V. These features combined with the low cost of this PV sub-module bring excellent prospects for its installation on PV cells to achieve a maximum efficiency in the solar to electric energy conversion. To finish, this PV sub-module costs less than $130, opening good perspectives for its popularization.