Smart Converters Research Group - Jun.-Prof. Stefan Mönch

The research group is working on highly efficient electrical energy converters for emission-free mobility of the future. Smart converters with intelligent operating concepts enable flexible and adaptable system integration of electrical sources, storage and loads as well as the coupling of the sectors electricity, heat and mobility.

In order to accelerate sustainable mobility and the energy transition, the group is researching

• highly efficient power electronics with new topologies and operating concepts,
• compact voltage converters for intelligent charging, storage and driving,
• electrocaloric heat pumps for cooling and heating in mobile applications.

The junior professorship was established on 15.12.2023 within the InnovationCampus Future Mobility (ICM).

The Innovation Campus is funded by the Ministry of Science, Research and Arts Baden-Württemberg.

EU EIC Pathfinder Challenge: Clean and efficient cooling (2024 - 2028)

We recently showed that ceramic-based electrocaloric regenerators are very interesting for cooling applications [A. Torelló et al., 2020, Science: https://doi.org/10.1126/science.abb8045, J. Li et al., 2023, Science: http://dx.doi.org/10.1126/science.adi5477]. However, the potential of polymer-based electrocaloric regenerators is more than one order of magnitude larger, thanks to a much larger voltage-driven entropy change. This is what we want to investigate in this project, namely polymer-based electrocaloric coolers. 

Hence, thanks to the recent progress made in electrocaloric polymers (ARKEMA Piezotech, France), in electrocaloric heat exchangers (Luxembourg Institute of Science and Technology (LIST), Luxembourg) and in electronic modules for electrocaloric cooling (University of Stuttgart, Germany) , combined with the scale up capabilities of this consortium (KEMET, Italy), the goal of this project is to make an air conditioning system with a high temperature span, a low temperature below room temperature, 1 kW-cooling power and 60%-efficiency. This requires a multidisciplinary approach combining 1) materials science (development of efficient electrocaloric materials and associated cooling modules), 2) thermodynamics (heat exchange and efficient cycles) and 3) electrical engineering (cooling control and energy recycling to increase efficiency). 

To reach this final goal, three objectives (KO*) have been defined in this project, as sketched in above figure. 

• Key objective 1 (KO1) – Development of electrocaloric polymers-based cooling modules (multilayer capacitors) with a high temperature variation.

• Key objective 2 (KO2) – Fabrication of regenerative heat exchangers with electrocaloric polymer cooling modules reaching a high temperature span and a cooling power density.

• Key objective 3 (KO3) – Reaching high efficiency (coefficient of performance COP relative to the Carnot-limit) by recycling electric energy. 

*More specific and quantitative objectives, approaches and KOs, where already defined project-internally and will be revealed in publications throughout the project duration.

• Design of highly-efficient charge recovery circuits (power electronics)
  • Discrete SiC and GaN power electronics for charging and discharging electrocaloric capacitors up to 1000V
  • Monolithic integrated 5-level multilevel GaN power converter (600V-class power ICs)
• Electrical and electro-thermal simulations and optimization
• Contribution to EIC Cooling Portfolio activities

HORIZON-JU-RIA - HORIZON JU Research and Innovation Actions (2025 - 2028)

HiPower 5.0 is driven by the challenges and ambitions addressed in the Green Deal and in the Chips Act, to develop new power electronics solutions to ensure Green Deal targets and to foster a resilient and leading edge all-European Value Chain, for tomorrow’s mobility solutions. Therefore, HiPower 5.0 aims for developing highly integrated eDrive components for the automotive and maritime domain using leading edge wide bandgap semiconductors and power electronics integration technologies. This includes the development of new GaN wafer materials with superior performance, first time 850 V monolithically integrated bidirectional GaN switches, enabling new topologies and unprecedented efficiency levels of 99%, as well as 1200 V GaN switches fitting the needs of 800 V battery electric vehicles. 
When developing these solutions, a resource-efficient and reliable design is considered to minimize CO2 footprint and extent the lifetime of power electronics components. 
Firstly, multi-physics simulation with its ability to model the complex interactions between electrical, thermal, electro-magnetic, and mechanical phenomena will be used. By simulating these interactions, the system design can be optimized while performances can be predicted under various operating conditions, reducing the need for prototyping, and cutting both time and costs of development. Secondly, new ageing models and prognostics concepts will be developed to finally enable an according evaluation of the set targets of the single applications. Supported by innovations in power electronics control and cooling the lifetime and reliability will be further enhanced.
To achieve these targets, the HiPower 5.0 consortium is composed along the whole value chain, starting from the GaN wafer and chips development, up to automotive and maritime Tier1/OEMs. This is accompanied by leading European universities and research organizations, guaranteeing a significant economic and scientific impact of the proposed work.

• Design and characterization of GaN-based inverter for wireless power transfer in iEESM machines
• Evaluation of 1200V and bidirectional blocking GaN transistors
• Evaluation of smart GaN power ICs

01.08.2025 - 30.04.2026

Cooperation: Fraunhofer Institute for Applied Solid State Physics IAF

15.05.2024 until 31.12.2024

01.01.2024 until 31.12.2024

Details: See project homepage