Power conversion systems are dependent on the performance and reliability of static converters. However, they are subject to frequent functional and environmental strains, which can induce failures. The anticipation of these failures is difficult but important so the operation of a system can be halted before a breakdown occurs. In the case of photovoltaic (PV) power plants, the system can be simplified into two distinct blocks: the solar panels/modules and the power inverter. A breakdown in either of these blocks can cause significant downtime in the system. Nevertheless, multiple solar module failures can often be tolerated and not lead to a total breakdown of the entire array, whereas a single component failure in the inverter can lead to a collapse of the entire system. Furthermore, solar panel/module manufacturers often offer warranties of up to 20 years, while warranties for inverters rarely reach the ten-year mark [1]. As such, the overall cost of a PV inverter can increase by a factor of two or three if it undergoes one or two failures during the life of the system. Although the market competition between PV inverter manufacturers has traditionally focused on the efficiency of their product, a failure that induces a downtime of just a few days can easily negate the yield attained through a 1% efficiency improvement. Oversizing the inverter or introducing redundancy into the inverter system is one option to improve reliability; however, often, this is not economical
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.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.