Highly Efficient 5 kW DC/DC Converter for a Low-Voltage Battery-Based Storage System

Suitable power electronics are essential for processing and distributing electrical energy from renewable sources.

Power Converter Systems

Our work in the field of converter systems focuses on the following areas:


Power Electronics for PV and Storage Systems


Power Electronics for Electric Mobility

The decarbonization of the energy systems used in the power and transportation sectors is crucial for conserving our planet for future generations. Renewable energy, energy storage and e-mobility will play a vital role in significantly reducing CO2 emissions worldwide. To ensure that our current fossil fuel-based energy systems can be transformed as required, we will need numerous power electronic systems for converting, storing and distributing electrical energy.

Fraunhofer ISE has many years of experience in developing customized power electronics for converter systems. To help contribute to the energy and transportation transition, our department is dedicated to developing converter systems that can be refined for a variety of applications. Power electronic systems that are already suitable for the next generation in terms of both commercial and technological aspects are essential for processing electrical energy and for integrating systems into an increasingly complex and intelligent energy and transportation sector.

By combining innovative hardware designs with the latest semiconductor technologies and optimized assembly, connection and cooling structures, we can develop compact, highly efficient converter systems in almost all power ranges. These can be designed for use in grid-connected, off-grid and hybrid applications with the required control technology. In addition to our research activities, we generate innovative ideas for next-generation power electronics that are close to being ready for production.


Our R&D services comprise:

  • Feasibility and concept studies for power electronic converters
  • Highly efficient and compact converter systems (stationary/mobile)
  • Conductive and inductive energy transmission systems
  • Integration of converters in accordance with device-specific standards
  • Innovative control system concepts and software development
  • Measurement, characterization and optimization of existing concepts and devices

In addition to researching converter systems, we run the Power Converters Lab at the Center for Power Electronics and Sustainable Grids at our Zinkmattenstrasse location. This allows us to work closely with the departments operating the Multi-Megawatt Lab and the Medium Voltage Lab, giving us access to additional infrastructure.

Center for Power Electronics and Sustainable Grids

Selected Research Projects



Increasing the Overall Efficiency of Self-Consumption Systems



Highly Dynamic Control of Photovoltaic Inverters



High Power Inductive – Automated, Wireless Fast-Charging Technology for Autonomous Mobile Robots and Industrial Trucks



Power Electronics – Intelligent and Reliable

Stephan Liese

Contact Press / Media

Stephan Liese

Power Converter Systems

Fraunhofer ISE
Heidenhofstr. 2
79110 Freiburg

Phone +49 761 4588-5890



YearTitle/AuthorDocument Type
20215-kW-DC/DC-Wandler mit hohem Teillastwirkungsgrad für 48-V-Heimspeicher
Hercegfi, P.
Conference Paper
2021Series-Resonant-Converter with Galvanic Isolation and >99% Efficiency
Bornwasser, J.
Conference Paper
2021Universelle Umrichterregelung für ein- und dreiphasige Systeme im Netzparallel- und Inselnetz-Betrieb
Siedle, C.; Reichert, S.; Stickan, B.; Rauscher, M.
Conference Paper
2020Analysis and Design of a Novel Six-Switch Five-Level Active Boost Neutral Point Clamped Inverter
Siwakoti, Y.P.; Palanisamy, A.; Mahajan, A.; Liese, S.; Long, T.; Blaabjerg, F.
Journal Article
2019Bidirectional inductive charging systems economical in the electricity grid: Development and application of a technology to boost electric mobility
Schumann, P.; Borrmann, D.; Mahajan, A.; Mittelsdorf, M.; Schember, T.
Conference Paper
2019Indirect Model Predictive Control of a Three-Phase Grid-Connected Siwakoti-H Inverter
Waris Begh, M.A.; Liegmann, E.; Karamanakos, P.; Mahajan, A.; Siwakoti, Y.P.; Kennel, R.
Conference Paper
2019A Novel Seven-Level Active Neutral-Point-Clamped Converter With Reduced Active Switching Devices and DC-Link Voltage
Siwakoti, Y.P.; Mahajan, A.; Rogers, D.J.; Blaabjerg, F.
Journal Article
2019Spectrum Shaping Methods for Predictive Control Approaches Applied to a Grid-Connected Power Electronics Converter
Stickan, B.; Rutquist, P.; Geyer, T.; Diehl, M.
Conference Paper
2018Dimensioning and comparison of circular and double D coil geometries for inductive charging of electric vehicles
Mahajan, A.; Reichert, S.; Nehlert, F.
Conference Paper
2018A New Seven-Level Active Boost Neutral Point Clamped (7L-ABNPC) Inverter
Siwakoti, Y.P.; Liese, S.; Mahajan, A.; Palanisamy, A.; Rogers, D.; Blaabjerg, F.
Conference Paper
2018A New Three-Level Three-Phase Boost PWM Inverter for PV Applications
Palanisamy, A.; Mahajaran, A.; Liese, S.; Siwakoti, Y.; Long, T.; Forati Kashani, O.; Blaabjerg, F.
Conference Paper
2018Which digital energy services improve energy efficiency?: A multi-criteria investigation with European experts
Goldbach, K.; Rotaru, A.M.; Reichert, S.; Stiff, G.; Gölz, S.
Journal Article
2017A 70 kW next generation three-phase solar inverter with multiple MPPTs using advanced cooling concept and stacked-PCB architecture
Freiche, R.; Franz, S.; Fink, M.; Liese, S.
Conference Paper
2017Comparison between grid-feeding and grid-supporting inverters regarding power quality
Reichert, S.; Griepentrog, G.; Stickan, B.
Conference Paper
2017Comparison of FPGA based control strategies (DDSRF-PI vs. State-Space Control) for grid connected inverters under grid disturbances
Mittwede, E.; Kern, J.; Schönberger, S.; Stickan, B.
Conference Paper
2017Highly efficient and compact single phase PV inverter with GaN transistors at 250 kHz switching frequency
Derix, D.; Hensel, A.; Freiche, R.
Conference Paper
2017Improved AC-current control based on state space control applied to solar string inverters
Rapp, T.; Liese, S.; Siedle, C.; Brand, M.; Rossa, A.J.
Conference Paper
2017Machine code functions in BIM for cost-effective high-quality buildings
Maurer, C.; Sprenger, W.; Franz, S.; Lodewijks, J.; Rüppel, U.; Kuhn, T.
Conference Paper
2017Machine-code functions in BIM for cost-effective high-quality buildings
Maurer, C.; Sprenger, W.; Franz, S.; Boudhaim, M.; Lodewijks, J.; Rüppel, U.; Kuhn, T.E.
Journal Article
2017Modulation scheme to improve the efficiency for low load operating points for a dual active bridge DC/DC-converter
Khani, M.
Conference Paper
2016DC/DC-converter for modular coupling of 48 V battery packs to a high voltage DC bus
Eberlin, M.; Khani, M.
Conference Paper
2016Design and development of LLC DC/DC converter for fuel cell range extender application
Mahajan, A.; Reichert, S.
Conference Paper
2016A novel control algorithm for grid-connected inverters improving power quality using voltage control and virtual impedance
Reichert, S.; Stickan, B.
Conference Paper
2016Stability analysis of droop-control in diesel-hybrid systems
Reichert, S.; Singer, R.
Conference Paper
2015Comparison of continuous and transition mode in a PV-booster with GaN-transistors and switching frequencies up to 250 kHz
Derix, D.; Freiche, R.; Schöner, C.; Hensel, A.
Conference Paper
2015Comparison of different control strategies for series-series compensated inductive power transmission systems
Tritschler, J.; Goeldi, B.; Reichert, S.; Griepentrog, G.
Conference Paper
2015Measurement results of a 22 kW bidirectional inductive charger
Goeldi, B.; Tritschler, J.; Reichert, S.
Conference Paper
2015Zukunftsfähige Systemtechnik für PV-Großkraftwerke mit erhöhtem Spannungsniveau
Liese, S.; Rogalla, S.; Schönberger, S.; Venkatapathi, R.
Conference Paper
2014Hoch effiziente induktive und konduktive Ladesysteme für die Elektromobilität durch den Einsatz von SiC Halbleitern: Vortrag gehalten auf dem 3. Symposium Elektromobilität 2014, Ostfildern/Stuttgart, Germany, 20.05.2014
Reichert, S.; Tritschler, J.; Goeldi, B.
2014Innovative state-space controller for an optimized low-voltage-ride-through behaviour
Eberlin, M.; Siedle, C.; Reichert, S.
Conference Paper
2014Neue Reglerstruktur für Netz- und Inselwechselrichter
Abbassi, N.; Reichert, S.
Conference Paper
2014Novel control structure for grid connected and islanding inverters
Abbassi, N.; Reichert, S.
Conference Paper
2014Power Electronics for Utility Scale PV Power Plants with Voltages Up to +/- 1500 VDC
Görden, T.; Liese, S.; Rogalla, S.; Venkatapath, R.
Conference Paper
2014A practical investigation of a high power, bidirectional charging system for electric vehicles
Tritschler, J.; Reichert, S.; Goeldi, B.
Conference Paper
2014System technology for the next generation village energy supply
Eberlin, M.; Reiners, F.; Stalter, O.; Franz, S.
Conference Paper
2014Verhalten eines dreiphasigen Dreipunkt-Wechselrichters mit Netzstrom-Zustandsregler bei dynamischen Einbrüchen der Netzspannung
Eberlin, M.; Reiners, F.; Siedle, C.; Stalter, O.
Conference Paper
2013Design and dimensioning of a highly efficient 22 kW bidirectional inductive charger for E-mobility
Goeldi, B.; Reichert, S.; Tritschler, J.
Conference Paper
2013Hocheffiziente, brührungslose und bidirektionale Energieübertragung für die Elektromobilität
Tritschler, J.; Reichert, S.; Goeldi, B.
Conference Paper
2013Innovative Leistungselektronik für photovoltaische Inselsysteme mit hybrider Blei-Lithium Batterie
Eberlin, M.; Reiners, F.; Stalter, O.
Conference Paper
2013Lichtbogendetektion in PV-Anlagen
Grab, R.; Häberlin, H.; Schmitz, R.; Philipp, S.; Schmidt, H.; Franz, S.; Laukamp, H.; Bopp, G.; Reil, F.
Conference Paper
2013Untersuchung des LVRT-Verhaltens parallelbetriebener PV-Zentralwechselrichter
Doetter, G.; Rogalla, S.; Bihler, N.; Siedle, C.; Burger, B.; Schaupp, T.; Kempen, S.; Garber, T.; Landwehr, F.; Lotzkat, W.; Ackermann, R.
Conference Paper
This publication list has been generated from the publication database Fraunhofer-Publica.