Measuring the current-voltage characteristics of solar cells

Solar cell parameters are measured during manufacturing process and they determine quality and properties of solar cells. Standard measurements of typical solar cell parameters (short-circuit current, open-circuit voltage and maximum power point) are performed in laboratory conditions under simulated sunlight (1 kW/m2) and temperature of 25º C and they do not describe solar cell operation under real environmental conditions. To get a better picture of solar cell operation in practical applications, it is necessary to measure its parameters while it is exposed to natural sunlight. In this paper a hardware solution for current-voltage characteristics measurement is presented. This solution is applicable in both cases - whether we measure under laboratory or real environmental conditions. Hardware solution is based on 8-bit microcontroller and circuit which simulates load. The load simulation is performed by MOSFET and operational amplifier. Results obtained by this hardware solution are generally acceptable, though certain disadvantages exist. Disadvantages and possible improvements of this solution are discussed