The CEA and Renault Group have jointly developed a new electronic power converter architecture integrated directly into the vehicle’s charger. The result of nearly three years of research and the subject of 11 joint patents, this power converter, developed from innovative materials and more compact, will reduce energy losses by 30%, improve the vehicle’s recharging time and guarantee the battery’s durability.

It will also be bidirectional by storing energy from the electricity network.

The organisations have combined their expertise in the field of on-board power electronics, in particular in the field of wide band-gap semiconductor materials, whether in gallium nitride (GaN) or silicon carbide (SiC).

As a result, the new architecture based on the wide band-gap semiconductor materials makes it possible to reduce energy losses by 30% during conversion, and to reduce heating by the same amount, making it easier to cool the conversion system.

Work to optimise the active (semiconductors) and passive (capacitors and wound inductive components) components has enabled a reduction in the volume and cost of the charger. Thanks to the use of ferrite materials, dedicated to high frequency, and a shaping injection process called ‘power injection moulding’, the converter has become more compact.

This new converter architecture offers a charging capacity of up to 22kW in three-phase mode, allowing for faster charging of the vehicle while ensuring the durability of the battery. It also allows the charger to be bidirectional, so that the energy stored in the battery can be fed back into the grid or used to supply the energy needs of an autonomous house, provided that the house is equipped with a bidirectional meter. The solution is compatible with the electromagnetic compatibility (EMC) standards of the networks and the car.

Renault advanced engineering chief Jean-Francois Salessy, said: “This project with the CEA has exceeded our expectations by confirming the ability to achieve the expected performance in terms of efficiency and compactness. It opens up strong prospects for power electronics, which is a real challenge in the electric vehicle, in order to make the best use of the batteries’ capacities. With bidirectional charging, the vehicle serves the electrical network and enables the end consumer to reduce energy costs.”