A method for accelerated ageing tests of photovoltaic inverters considering the application's mission profiles

This paper presents a new method for the accelerated ageing tests of photovoltaic inverters, created by analyzing the mission profiles of the current and ambient temperature extracted over several years from multiple photovoltaic plants located in France. It is 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, thermal cycling is applied simultaneously by varying the ambient temperature as in the real application, and by applying current injections with relatively long durations, which will lead to a rise in the temperatures of the DBC substrates and the coolers. This method should show better representation of the thermal behavior of DC/AC inverters used in photovoltaic applications, and is expected to give results that are more representative than traditional power cycling, and thus reducing the favoring of certain failure modes to the detriment of others.