The Fraunhofer Institute for Energy Economics and Energy System Technology IEE is working in the PVCharge project together with partners from industry and research on solutions for the direct charging of electric vehicles with solar power. The aim is to reduce losses in energy conversion, increase the share of PV electricity in vehicle batteries, and at the same time enable grid-supporting functions. In this way, energy efficiency is to be increased and the integration of renewable energies into existing grids improved.
The research project “PVCharge – Multifunctional Power Electronics for PV Parking Areas” is coordinated by Fraunhofer IEE and carried out together with Siemens AG, Infineon Technologies AG, Flavia IT Management GmbH, and Bonn-Rhein-Sieg University of Applied Sciences. The aim is to efficiently harness synergies between industrial photovoltaic installations and electric vehicles and thus technically and economically optimize direct PV charging. The focus is on larger PV installations such as those that can be constructed above or near supermarket or company parking lots.
New approaches for the direct PV charging of electric vehicles
The aim is to make the direct charging of electric vehicles (EVs) at photovoltaic installations (PV systems) more efficient and more flexible. “In this process, the electricity from the PV system must pass through at least four conversion stages before it reaches the vehicle battery. Each of these conversion stages is associated with losses, which means that around 10 percent of the solar energy is lost unused. In PVCharge, we are researching an approach that allows this conversion to take place in two instead of four steps, saving around half of the losses,” says Dr. Sebastian Sprunck, project coordinator at Fraunhofer IEE.
Fraunhofer IEE is developing a test environment for this purpose in order to validate the approach in practice. An existing rapid-control prototyping system is being expanded to emulate the behavior of various current and future EVs at the charging stations. In addition, an in-house PV system is being used for experimental trials to test the system concept under realistic conditions with regard to both system and personnel safety.
Siemens AG is examining the safety-relevant issues and the integration of the charging stations. “The spatial extent of such a PV parking facility, the variable number of electric vehicles, and the various usage scenarios require innovative approaches to system monitoring and interaction of the different converter stages,” explains Sebastian Nielebock, project manager at Siemens.
The interaction with the power grid is also being taken into account. “This interaction with the grid requires robust, dynamic, and durable power electronics,” says Dr. Peter Friedrichs, Fellow SiC Innovation at the Infineon Technologies AG. Infineon is developing a demonstration inverter based on novel semiconductor modules that enables this interaction.
At the Bonn-Rhein-Sieg University of Applied Sciences (H-BRS), work is being carried out in parallel on adapting the MPP tracker. “In such a system, the MPP tracker must be able to cope with fast and significant changes in DC voltages when the power balance of the system changes at short notice, for example due to specifications from the grid operator, a cloudy sky, or the connection and departure of vehicles,” explains Prof. Dr. Marco Jung, Professor of E-Mobility and Electrical Infrastructure at H-BRS and Head of the Power Converters and Electrical Drives Department at Fraunhofer IEE.
Flavia IT Management GmbH is developing the IT-side basis for the interaction of user preferences, grid specifications, and billing options with its ‘Gridware’ platform. “There are numerous user wishes, requirements of grid operators, approvals, data formats, billing options, and communication interfaces to be taken into account, which must be handled in real time and with high precision,” says Georg Schmitt from Flavia IT Management.
Survey for grid operators
The project team is currently inviting grid operators to participate in the PVCharge grid operator survey. It is aimed at operators of low- and medium-voltage grids in Germany and is intended to help capture requirements and perspectives for more efficient use of renewable energies. The results will feed into the further project work and will be used to adapt the content and priorities of the planned stakeholder workshops specifically to practical needs. Interested grid operators are warmly invited to register for the first stakeholder workshop “Grid Integration and Interfaces” on November 19, 2025, by providing their contact details in the survey form. The workshop is expected to take place as a hybrid event in Kassel and via MS Teams.
The PVCharge project is funded by the Federal Ministry for Economic Affairs and Energy with 3.5 million euros and runs from April 2025 to March 2028.
