Revising the Bypass Diode Test to Incorporate the Effects of Photovoltaic Module Mounting Configuration and Climate of Deployment

Bypass diodes provide protection to Photovoltaic (PV) modules against partial shading. The existing qualification test for bypass diodes within the International Electrotechnical Commission (IEC) 61215 standard, entitled ‘Bypass Diode Test’ (BPDT), does not take into account the differences in end use environments experienced by PV modules due to different climates of deployments and mounting configurations. The current test is shown to be inadequate for climates/mounting configurations that result in high temperature end use environments for PV modules. A thermal model for bypass diode temperature in field was developed and applied to modules deployed in 16 representative climatic zones and two mounting configurations (rack mount and roof mount). A revised test condition was developed by varying the forward current through diodes and module temperature to minimize the false positive and false negative errors.