Renault Group and the French Commissariat for Atomic Energy and Alternative Energies CEA are jointly developing a bidirectional charger with very high efficiency for electric vehicles. The compact and highly efficient system will reduce energy losses during charging by 30 per cent and thus supply the vehicle battery with electricity significantly faster. It will also be vehicle-to-grid capable (V2G) and will be able to feed energy from the battery back into the grid to optimise grid operation and compensate for fluctuations in renewable energy. The innovative charger will be used in Renault’s production models by the end of the decade.
At the heart of the bidirectional charger is a new electronic power converter architecture integrated directly into the vehicle’s charger. The converter is the result of almost three years of research and combines eleven joint patents. It is made of innovative materials and is more compact than previous systems. The new architecture, based on wide bandgap semiconductor materials such as gallium nitride (GaN) or silicon carbide (SiC), makes it possible to reduce energy losses during voltage conversion by 30 per cent and reduce heat generation by the same amount, which in turn makes it easier to cool the system.
Less volume, more power
In addition, by optimising the active components (semiconductors) and passive components (capacitors and wound inductive components), the Renault Group and CEA development teams were able to reduce the volume and cost of the charger. Among other things, they were able to make the voltage converter more compact by using ferrite materials suitable for high frequencies. The innovative manufacturing process of powder injection moulding also contributes to the miniaturisation of the system.
This new converter architecture enables a charging power of up to 22 kW in three-phase operation, which enables faster charging of the vehicle while ensuring battery durability. In addition, the charger can be operated bidirectionally, so that the energy stored in the battery can be fed back into the grid or used to meet the energy needs of an autonomous house. Prerequisite: The house is equipped with a bidirectional meter. The solution is compatible with the electromagnetic compatibility (EMC) standards of the grids and the vehicle. www.renault-presse.de