Power Electronics Solar Inverter on a Biosourced and Biodegradable Substrate – Thermal Study

This paper presents a comparative study between traditional and sustainable approaches on a power electronics inverter; it focuses on the thermal management of the DC-AC bridge thermal losses. The system is inspired from state-of-theart designs of photovoltaic inverter DC-AC stages. We realized a design on a traditional printed circuit board Flame Retardant 4 (FR4) substrate, made of 4 copper layers (further called “reference design"). An adaptation of this design was prepared to implement it on a novel biobased and biodegradable substrate based on polylactic acid (PLA), flax fibers and biosourced flame retardant, with only 2 copper layers. Because this composite has a reduced glass transition temperature compared to FR4, it makes it more sensitive to intense thermal dissipation. In this system, the thermal dissipation is achieved through the PCB with thermal vias. An analytical modeling was performed to evaluate the thermal resistance of the vias in both designs and the resulting increase of temperature of the substrate. Thermal infrared measurements were then conducted on both designs, at selected operating points to evaluate the possibilities and limitations of the bio-substrate on such application.