Durability Performance Testing of SiC Diodes for use as Bypass Diodes in Photovoltaic Modules

When a bypass diode (BPD), which is a protective element in the photovoltaic module, fails owing to a short circuit, the faulty BPD generates heat, creating a risk of burnout. In this study, durability tests were conducted simulating the use of three different types of diode—silicon Schottky barrier diode (Si-SBD), PN junction diode (PND), and silicon carbide SBD (SiC-SBD)—as BPDs to investigate the specifications of diodes suitable for use as BPDs. The PND and SiC-SBD models, which have a large forward voltage drop, generated a large amount of heat, and the SiC-SBD model suffered thermal failure at approximately 10 cycles. However, all the diodes exceeded the junction temperature during testing. This reveals the need to implement heat dissipation measures to improve the long-term durability of BPDs.