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

Abstract

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.

A Review on IGBT Module Failure Modes and Lifetime Testing

“…However, real applications are characterized by complex load profiles, resulting in complex junction temperature profiles as shown in Fig. 17a [21,113,[123][124][125]. The first step for lifetime prediction is to decompose these complex profiles into sets of simpler identical power cycles as given in Fig.…”

Power Electronics Reliability: State of the Art and Outlook

“…Application-oriented testing under a representative mission profile can be used to check if the dominant failure mechanism remains the same with dynamic stress levels. In [80][81][82], power modules and capacitors are tested with a sequence of stress levels emulating PV applications. The daily profile of solar irradiance and ambient temperature is used [82] with a scaling factor to accelerate the test.…”

Limitations and Guidelines for Damage Estimation Based on Lifetime Models for High-Power IGBTs in Realistic Application Conditions

“…The name originates from visual analogies of the counting process with rain drops falling on a pagoda-shaped roof. The rainflow counting has nowadays been commonly applied in the decomposition of thermal stresses for powerelectronic devices [5]- [7], [9], [18], and is assumed as the reference for cycle counting in this paper.…”

“…Power-electronic devices operating in commercial applications are suffering varying temperature profiles, as they are exposed to a variety of ambient and load conditions. Even if, in some cases, there is sufficient information available to construct the expected temperature profile of a device over a full calendar year of operation [5]- [7], it is not feasible to test these profiles in a dedicated power-cycling test [8]. However, the data associated to a mission profile can be analysed and decomposed into elementary stress cycles with well specified parameters e.g.…”