Effects of current mismatch due to uneven soiling on the performance of multi-crystalline silicon module strings

Photovoltaic (PV) module operation is critical in PV systems for optimum generation of electrical power. Modules installed in the field suffer uneven soiling caused by bird droppings and dust build-up on their front surface. This study investigated the impact of partial shading caused by non-uniform soiling on the electrical characteristics of multi-crystalline silicon (mc-Si) modules and strings, and compared this with simulated I-V parameters. Light and heavy uneven soiling on mc-Si solar cells resulted in current mismatch which can be simulated. The effects of partial soiling on the I-V characteristics of mc-Si module strings were experimentally measured and agreed with the simulated results.