Sustainability in power electronics is a recent research topic. It takes place among current actions to grasp design choices that enable eco-design and circular economy in the domain. This paper shows the results and analysis of a literature review at the intersection of power electronics and sustainability without considering the reliability study of the power electronics systems. The first part explains the scope of the study. The second part shows a bibliometric analysis of the collected publications that underlines a pioneering position at the European level. The third part details the state-of-the-art and its analysis over four investigation topics which are: tools and methods, indicators, circularity and materials. This paper and the work behind are the results of collaboration at the French national level, as part of the workgroup CEPPS (Convertisseurs Electronique de Puissance Plus Soutenables—More Sustainable Power Electronics Converters) supported by the CNRS (Centre National de la Recherche Scientifique—French National Centre for Scientific Research) research group SEEDS (Systèmes d’énergie électrique dans leurs dimensions sociétales—Societal dimensions of electrical energy systems).

A methodology for the design of compact transformers operating at high frequency is presented in this article. A particular emphasis is paid to the thermal management of the magnetic core and of the winding components. For a 7 kW dual active bridge dc–dc converter, the objective is to reduce the core volume (99%) and integrate the serial inductance (8.7 μH) as being the leakage inductance of the transformer. A parametric study shows that the heating in the copper winding is very sensitive to the anisotropic thermal conduction behavior of the wire. Due to this characteristic, a pot-core configuration is prone to a higher warming compared with the E-E core geometry, as the efficiency of the winding cooling is lower. In order to take part of the self-shielding ability of pot cores, we studied new configurations in which internal thermal drains are inserted into voids specially designed to shorten the distance between the external cooled walls and the hottest points of the winding. The heating of internal components of the transformer and resulting thermo-mechanical stress peak is reduced by 40% paving the way for robust transformers with a power density that could theoretically reach up to 200 kW/dm ³ .

The current trend towards the rise in the operating frequency in power electronics allows a dramatic miniaturization of power converters but requires reliable passive components. Spinel ferrites could be appropriate magnetic materials for transformers and inductors, within the range 0.5 – 5 MHz, providing that power core-loss, enhanced by the frequency rise, remains low. This work investigates the opportunity to shape magnetic cores by Powder Injection Molding (PIM) while keeping a low power dissipation in components. It paves the way for designing new core geometries incorporating additional functions such as thermal management. A commercial Mn-Zn granulated ferrite powder was used in this study. The densification state of the ferrite feedstock (wax binder system) was investigated after injection and debinding in samples (ring shaped cores) sintered with different temperatures: 1140, 1145, 1150, 1155 and 1160°C/4h. Low carbon content (< 100 ppm) was confirmed (by IGA and DRX) revealed that the spinel phase formation was fully achieved after sintering. Cores losses data (from 100 to 900 kHz at 50mT) at different temperature (from room to 110°C) were analyzed by separating the contributions of the hysteresis (Ph ~ A.f), eddy current (Pe ~ B.f²) and residual (Pr~C.fn, with n>2) losses. The evolution of the total power losses (Pt) for toroids made by PIM were compared to the ones of samples fabricated by uniaxial compression (UC). It appears that the losses by hysteresis were always lower for PIM than for UC whereas it was the opposite for eddy current and residual losses. Microstructural analyses showed that open porosity plays an important role in this behavior.

To promote the development of thermal energy storage (TES), the sodium acetate trihydrate (SAT) presents interesting thermal properties. However, this material may suffer from aging throughout thermal cycles. Various solutions were explored in the literature to limit this aging, mainly based on the use of additives such as water. In this study, two samples were prepared. The first one consisted of raw SAT material whereas 3 wt.% of supplementary water has been added to the second one. They were then poured into 350 cm³ bricks, which were placed in an experimental test bench. After 35 cycles between 20 and 70 °C, a drop of about 10% of the latent heat was observed for the first sample. This behavior was like the literature data. For the second sample, the decrease of latent heat was more rapid (about 30%). Contrary to our expectations, the water addition seems not beneficial for the improvement of thermal stability. Interestingly, we noticed that the drop of the latent heat was fully reversible after sample stirring. This degradation might not be related to a thermal destructive mechanism but rather to a global segregation phenomenon. This segregation may be due to the breaking of hydrogen bonding between anhydrous sodium acetate and water, resulting in the separation of the two species.