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Power integrated systems

Physical failure and resistance of power integrated systems 

The work concerns the system converters integrated with power semi-conductors. These devices exists  in railway sectors for the traction, must be integrated in roadways for the development of electric and hybrid vehicles but also in aeronautics, for actuator control (in case of electrical aircrafts). Independent of the mission profiles and the constraints in these three different transport domains, the common factor is to own a synergy and a significant dynamic research.

These devices extend towards high integration limits (in order to reduce the volume and weight of equipment) and hence towards elevated power densities. The subsequent consequence is they are subjected to strict environmental conditions in terms of temperature levels and temperature variations. The earlier ones reduce the reliability and the next worsens the degradation.

 

The research works aims at understanding the physical mechanisms of degradation and aging of these devices. The aging tests, with help of original tools, coupled with digital modeling of electrothermic and thermomechanic behavior of these devices, their usage conditions, permits to highlight the failure mechanisms and to evaluate the technologies. The company approach is the physical approach of reliability. The objective is to improve the reliability of the systems built in the vehicles.

Possibility of the wide band Gaps components for the transports

This activity is extended to wide band gaps semiconductors components mainly silicon carbide (SiC) in order to investigate their usage possibilities in transport systems. This is justified by the need of power electronics in the high temperatures environments which became a major strategic objective for transport domains.

In fact the active components with silicon base are limited physically in their usage when there is a simultaneous usage in elevated pressure limits and ambient temperatures are needed. The materials ‘grands gaps’ (SiC, GaN et diamond) presents the advantage of limits exceeding capacities. Their usage appears like a reply to the very strict temperature environments and permits for ex, cooling systems reduction, but equally a rise in commutation frequency which leads to the reduction of passive component’s volume.  This need was first felt in the aeronautical domains, as a part of developing aircrafts ‘more of electric’ but the movement is followed in the railway and automobile domains. These works, initiated with the academic and industrial partnerships, has an objective of demonstrating the contribution which could constitute the usage of these materials for the transports.