Exploration and comparative study of partial power converter architectures for electric traction (Ref 09 EN)

IFP Energies nouvelles (IFPEN) est un acteur majeur de la recherche et de la formation dans les domaines de l’énergie, du transport et de l’environnement. De la recherche à l’industrie, l’innovation technologique est au cœur de son action, articulée autour de quatre priorités stratégiques : CLIMAT, ENVIRONNEMENT ET ÉCONOMIE CIRCULAIRE, ÉNERGIES RENOUVELABLES, MOBILITÉ DURABLE et HYDROCARBURES RESPONSABLES.

L’engagement d’IFPEN en faveur d’un mix énergétique durable se traduit par des actions visant :

• à gagner en efficacité énergétique ;
• à réduire les émissions de CO2 et de polluants ;
• à améliorer l’empreinte environnementale de l’industrie et des transports ;

tout en répondant à la demande mondiale en mobilité, en énergie et en produits pour la chimie.

Dans cet objectif, IFPEN développe des solutions permettant, d’une part, d’utiliser des sources d’énergie alternatives et, d’autre part, d’améliorer les technologies existantes liées à l’exploitation des énergies fossiles.

Exploration and comparative study of partial power converter architectures for electric traction

Power electronics converters installed in electric vehicles must meet increasingly stringent requirements in terms of energy performance, size, reliability, and cost. As such, the inverter, which is part of the powertrain, is often a two-level voltage inverter directly interfaced with the battery. Although this solution is mature and inexpensive, it is subject to battery voltage fluctuations depending on its state of charge, which can impact the accessible operating points. One solution used in the industry is to interface a DC-DC boost stage upstream of the inverter in order to benefit from a regulated bus voltage supplying the inverter independently of load fluctuations. However, the introduction of a second conversion stage is costly and reduces the efficiency of the powertrain.

So-called “partial power” architectures appear to be a promising alternative to conventional topologies. These architectures allow only a fraction of the total power to be transferred through an active converter, with the rest flowing through a direct path without causing losses. This approach can therefore offer a potential advantage in terms of overall conversion efficiency and in the sizing of converters with regard to the constraints on the active components required.

Main objectives of the internship:

The objective of this internship is to study the feasibility of implementing a partial power converter in the traction chain. This study should enable us to quantify the potential efficiency gains of a partial power solution, as well as its disadvantages in terms of cost and size.

To do this, it will be necessary to compare different partial power architectures, taking into account the various possible interconnection modes (ISOP, IPOS, etc.) and also the impact of the possible addition of auxiliary Buck, Boost, or Buck-Boost converters to control the bus voltage. An analytical model of the solutions studied, their modulation, and their control will need to be developed. Finally, a study of the efficiency of this architecture will be carried out, with particular attention paid to comparing it with the more conventional structure of the boost interfaced upstream of the inverter. Depending on progress, prototyping of a partial power solution for experimental validation may be considered.

The proposed internship could lead to a thesis dedicated to the analysis of a traction chain incorporating an innovative DC-DC converter. The latter would provide the degree of freedom needed to optimize the operation of electric traction converters in real time according to various criteria.

Candidate Profile:

Master's degree student or final-year electrical engineering student with solid knowledge of power electronics.

• Solid knowledge of common static converter topologies in power electronics
• Knowledge of converter and electrical machine control and management.
• Proficiency in simulation software (MatLab/Simulink, LTSpice, etc.).
• Curiosity and initiative

Keywords: Power electronics, Inverter, DC-DC, partial power converter, modeling, electric powertrain.

Duration and location: 6 months, between march and august 2026, in Rueil-Malmaison.