A research consortium led by Fraunhofer Institute for Solar Energy Systems (Fraunhofer ISE) has presented a megawatt charging system for electric vehicles achieving an efficiency of 99.26%, following the completion of the HV-MELA-BAT project.
The initiative, launched in 2023, brought together partners including Fraunhofer IVI, Mercedes-Benz Energy, STS Spezial-Transformatoren Stockach and Motion Control & Power Electronics. The project aimed to advance high-power charging technologies based on both the Combined Charging System (CCS) and the Megawatt Charging System (MCS).
Following its completion in July 2025, the consortium reported that the newly developed system combines a dedicated power electronic inverter with a high-current contact system, achieving performance levels above many existing megawatt charging solutions.
According to Fraunhofer ISE, the system’s galvanically isolating DC/DC converter reaches a volumetric power density of 9 kW per litre and an efficiency of 99.26%, which the institute described as “record-breaking.” The converter delivers 250 kW per unit, with four modules operating in parallel to enable charging capacities of up to 1 megawatt.
The inverter is based on a series resonant converter topology and operates at switching frequencies of up to 200 kHz, allowing for smaller components such as transformers and inductors, reducing both material use and system size.
To address grid limitations, the system integrates a buffer storage unit using second-life batteries from passenger vehicles supplied by Mercedes-Benz Energy. This approach reduces the required grid connection capacity to around 500 kW while still enabling megawatt-level charging, helping to manage peak loads and ease pressure on local electricity networks.
The project highlights ongoing efforts in Europe to develop scalable, high-efficiency charging solutions for heavy-duty and passenger electric vehicles as megawatt charging standards continue to evolve.
