A Method for Accelerated Aging Tests of Power Modules for Photovoltaic Inverters Considering the Inverter Mission Profiles

This paper presents a new method for the accelerated ageing tests of power semiconductor devices in photovoltaic inverters. Mission profiles are analysed: output current and ambient temperature are extracted over several years from multiple photovoltaic plants located in France. It is then proposed to create a particular ageing profile which takes into account not only the different constraints of the application of the photovoltaic inverters (high-frequency switching and sinusoidal-shaped current), but also reproduces a typical profile of the output current of photovoltaic inverters. Similarly, the ambient temperature varies as in the real application. By applying current injections with relatively long durations, the DBC (Direct Bonded Copper) substrates and the coolers are subjected to high temperature swings. This method should show better representation of the thermal behavior of DC/AC inverters used in photovoltaic applications, and is expected to show more representative results than traditional power cycling, thus reducing the favoring of certain failure modes to the detriment of others.