Center for Power Electronics and Sustainable Grids

As part of the “Center for Power Electronics and Sustainable Grids” at the new Zinkmattenstrasse location in Freiburg, Fraunhofer ISE has taken three new laboratories into operation. With the Power Converters Lab, the Multi-Megawatt Lab and the Medium-Voltage Lab, unique facilities are now available for research and development on power electronics and dynamic grid control. These reinforce the leading position of our Institute in the international research landscape and en able it to meet impending challenges in the electricity sector.

Direct Connection to the High-Voltage Grid
The new laboratory premises has its own connection to the 110 kV high-voltage grid. Our own 40 MVA voltage transformer feeds a proprietary research grid which allows the investigation – without disturbing third parties – of the effects of voltage changes, the propagation of harmonics between the low-voltage, medium-voltage and high-voltage grids, and special grid situations such as islanded grids. The medium-voltage transformers with different power ratings up to 6.4 MVA and variable voltages between 260 V and 36 kV are available to supply power to the test fields in the laboratory.

Power Electronics in the Multi-Megawatt Range for Low and Medium Voltages
In the low-voltage range, Fraunhofer ISE has created the technical conditions to operate power converters up to the multi-megawatt range. With this, we are equipped for current and future developments of e. g. larger PV and battery inverters. Furthermore, laboratories equipped with special safety technology allow the development of power electronics with a direct connection to the medium voltage grid. Power electronic devices can be operated in a large climatic chamber at temperatures between -30 °C and +80 °C and adjustable humidity, to allow reliability and lifetime questions to be investigated. The activities focus on efficient, compact and reliable inverter approaches for grid applications, railway or medical technology, and also novel system concepts e. g. for PV and wind power plants, battery systems, electrolyzers or larger electricity supply systems.

Inverters for Reliable Grid Operation
Modern inverters can stabilize the electricity grid and must be further developed to make them future guarantors of reliable grid operation. Their electrical characteristics are decisive for this role. Our highly dynamic 1 MVA grid simulator allows us not only to investigate the reaction of inverters to dynamic changes in grid frequency and grid voltage, but also to analyze their harmonic behavior, e. g. by impedance spectroscopy. Furthermore, test rigs for RLC resonators are applied to investigate the behavior of islanded grids. Our new, high-performance Fault Ride-Through facility enables the dynamic behavior of generator systems to be tested not only for under-voltage ride-through (UVRT) during short periods of low voltage but also for over-voltage ride-through (OVRT). An important research focus is the development of voltage-controlled and grid-maintaining inverters for future electricity grids with a large share of renewable sources, as well as tests of micro-grid applications and improvements in control technology.

Aggregation of Competence and Services for Power Electronics
Our activities in the medium and low power ranges are now also located in the new premises. They encompass research, development and testing of new components and technology, of converter systems close to production readiness and power electronics in grids. We deploy this concentrated competence in diverse applications, e. g. in photovoltaics, energy storage, charging infrastructure for electromobility, electricity grids, railways, aviation and space transport. Our accredited TestLab Power Electronics also profits from the new premises with an expansion of the addressed power range and the extent of the offered characterization and testing services. The electrical properties of the test objects can be analyzed with greatest precision due to the existing, highly accurate power measurement technology.

Analysis and Testing of Intelligent Grids
The center with its Digital Grid Lab offers extensive access to intelligently interconnected energy systems. With this, we can test both individual solutions and complex systems in realistic surroundings. Our research activities there concentrate on digitalization and intelligent operation management, as well as sustainable grids and stronger intersectoral coupling.

 

Technical Facilities

Power Converters Lab Bidirectional DC sources (up to 1000 V / 600 A) Machine emulator (160 kVA) and grid simulator (30 kW) Load resistance for DC and AC voltage (200 kW) Programmable non-linear loads (3-phase, 230 V / 16 A) High-resolution, broadband oscilloscopes and sensor heads Multi-channel systems and accurate power measurement Measurement EMC disturbance (up to 200 AAC / 400 ADC) High-resolution, high-frequency thermography camera Accurate inductivity measurement instrument and impedance analyzer Multi-gate vector grid analyzer Hardware-in-the-loop (HIL) system from OPAL-RT Vapor-phase reflow soldering system Fine-placer microscope soldering station Test stand to characterize SiC/GaN semiconductors   Multi-Megawatt Lab In-house connection to 110 kV grid (20 kV / 40 MVA transformer) Highly accurate, broadband measurement up to 110 kV Test fields up to 7 MVA and from 260 V to 1000 V PV simulator (2000 V / 1.4 MW) Bidirectional battery simulator (750 V / 1 MW) High-dynamic grid simulator with reverse feedback (1 MVA) UVRT and OVRT test unit for test specimens up to 10 MVA Mobile UVRT test container (4.5 MVA) Inductive and capacitive loads (7 MVAr) Anti-islanding test stand (400 kVA) Climatic chambers for large equipment (-30 °C to +80 °C) High-accuracy power measurement (1000 V / 5000 A)   Medium Voltage Lab Test field with medium-voltage connection (20 kV / 20 MVA) Medium-voltage DC source (40 kV / 660 kW) Medium-voltage resistor (20 kV / 1 MW) Medium-voltage transformer (3 to 30 kV / 2.5 MVA) Railway transformer (16.6 Hz / 15 kV / 200 kVA) Semiconductor test stands to characterize leakage currents (to 30 kV), avalanche effects (to 4 kV / 100 A) and switching losses (to 20 kV / 1000 A   Digital Grid Lab Simulator for variable, electrical load profiles PV simulator for dynamic IV characteristics HIL system to model thermoelectric load profiles Test stand for battery management systems Grid-connected charging stations for electric vehicles IT-monitoring platforms for living laboratories and field tests