Design of bypass diodes in improving energy extraction of solar PV systems under uneven shading conditions

Solar photovoltaic (PV) energy is becoming an increasingly important part of the world´s renewable energy. To enhance energy conversion efficiency, bypass diodes have been used in PV systems. The usage of bypass diodes is particularly effective when a PV system is under an uneven shading condition. However, shading is normally applied to a PV array in very random manners, making shading analysis and improvement contributed by the bypass diodes extremely hard to access. This paper performs a comprehensive study on the PV array energy extraction characteristics under a variety of shading conditions. Based on the study, an enhanced bypass diode design in terms of doping concentration is proposed. Investigation of the proposed bypass diode scheme shows that such bypass diode design is effective in improving energy capture efficiency under diverse shading conditions. Significant simulation studies are conducted for detailed evaluation of a PV system with the different bypass diode schemes and process.