​Liten, a CEA Tech institute, recently worked with several other labs to develop a test bench to help better understand the failure mechanisms of insulated-gate bipolar transistors (IGBT) when used in photovoltaic applications and more effectively dimension components to lengthen system lifespans. The test bench was developed under the Memphis research project, which is backed by France's National Research Agency (ANR).

The novel research led to the development of a power component cycling tool with the capacity to diagnose component health at regular intervals. "We determined the aging cycles specific to photovoltaic applications and applied them to a sample of IGBT modules for a 1,000-hour statistical study, which is equal to five to ten years of operation in real-world conditions," said one researcher. "The VCE voltage, which is an indicator of the temperature inside the component, can be measured without making any modifications to the test bench." The test bench was ingeniously designed so that the energy coming out of one IGBT is injected into the other, reducing the system's energy consumption to just a few percent of the power in the actual inverter. This makes it possible to study high-power systems with reduced-scale lab equipment.

The test bench is now operational and can be used to gain deeper insights into component aging to improve PV inverter reliability.