This project will present the possibility of designing a simple self-powered solar tracking sensor circuit using a Dialog Semiconductor SLG88103 operational amplifier. The complete circuitry is self-powered, since it uses only the power obtained from the photodetectors. There is no need for an additional external power supply. The photodetectors are arranged so that they can sense the direction of solar irradiance. Based upon the signal processing circuitry at the outputs, two highly sensitive voltage signals are generated. These signals correspond to the pitch and roll angles of the sun with respect to the photodiodes. The circuitry has an inherent automatic gain control. Therefore, the output signals are only proportional to these angles and not to the solar irradiation level.
The Sensor Circuitry
The schematic of the proposed simple self-powered solar tracking sensor circuitry is presented in Figure 1. Processing the signals from the photodetectors requires only two operational amplifiers and several resistors. Additionally, as the photodetectors (photodiodes PDYU1, PDYU2, PDYD1, PDYD2, PDXR1, PDXR2, PDXL1, and PDXL2) work in the photovoltaic mode the generated power is significant enough to power the op-amps. Both the X and Y direction use four photodiodes (PDYU1, PDYU2, PDYD1, and PDYD2) connected in series to power on the operational amplifiers OP1 and OP2. The corresponding voltages, obtained at the photodiodes when in photovoltaic mode, are given by:
where E is the solar irradiance. The output voltages VX and VY are given as:
The realization of a simple self-powered solar tracking sensor circuitry will be based on the extremely low-power characteristics of the SLG88103 operational amplifiers ....Read more »