Your reliable partner for power electronics in Rostock
Our partners
A selection of the institutions and companies we work with and with whom we have already implemented many successful projects.
How we work
Problem definition & requirements survey
- Analysis of customer requirements
- Technological feasibility assessment
Research & concept development
- Use of state-of-the-art research knowledge
- Simulation and modeling
System design & prototyping
- Development of innovative hardware/software solutions/on-site measurements
- Prototype construction, model development and test series
Validation & optimization
- Model studies
- Test bench tests & laboratory validation
- Optimization based on measurement results
Implementation & technology transfer
- Support with product integration
- Knowledge transfer & training
Long-term support & further development
- Sustainable partnership
- Research into future technologies
Our expertise
Grid-forming inverters & GFM methods
MOREOur benchmark models already help transmission system operators ensure tomorrow’s grid stability today.
Frequency stability
Our control concepts ensure frequency stability even with fluctuating infeed and loss of conventional instantaneous reserves.
Since power electronics do not provide stored energy, the central challenge lies in the immediate balancing of power. This requires a coordinated overall concept of generating units, in which the grid-side converter can actively provide grid services – reliably, dynamically, and controllably.
Showcase: Offshore wind farm as a grid-forming system
We have developed a holistic concept for offshore wind farms in which all participants act as grid-forming elements – from the wind turbines to the offshore HVDC connection to the onshore station, both on the AC and DC side.
The onshore HVDC station acts as a conventional power plant in relation to the grid – including all relevant systemservices, which are provided entirely by the wind turbines.
Voltage source behavior
The ideal image of grid-forming inverters is a voltage source behind a defined impedance – analogous to the clamping behavior of a synchronous machine. Negativesequence system voltage should therefore also be avoided.
The greatest technical challenge lies in the combination of voltage source behavior with active current limitation – two requirements that are fundamentally contradictory. While synchronous machines can provide a multiple of their rated current at short notice during grid events, this can only be achieved with power electronic systems at considerable cost.
Grid-forming converters must therefore demonstrate similar grid-supporting behavior – while at the same time strictly limiting the current. In close cooperation with transmission grid operators, we analyze these concepts with regard to their practical suitability. The results flow directly into studies and the further development of technical regulations (e.g. FNN test scenarios).
Black start capability
Black start capability is becoming increasingly important in the course of the energy transition – without it, a secure energy supply with a high proportion of renewable energies is hardly feasible.
This capability depends largely on the specific control of the respective system. A wind turbine only requires sufficient energy (e.g. from a battery or a diesel generator) to start the auxiliary systems, position the rotor in the wind and approach the first operating point. Such auxiliary sources are connected via power electronic interfaces.
In addition, larger energy storage systems could not only enable black start, but also provide additional grid services such as primaryreserve when wind availability is low.
In order for the black start capability of individual systems to become an actual grid restart capability, they must also have grid-forming properties – see frequency stability and voltage source behavior
Wind Energy & HVDC Control
MORETogether with manufacturers and grid operators, we develop technologies for implementing grid code specifications, grid forming functions and innovative strategies for stable, dynamic and sustainable grids.
Full converter control and grid code compliance
Full control over the converter – from modulation to current control for precise and consistent system management.
Compliant voltage and power regulation – even under increasingly demanding conditions.
To ensure reliable operation even in the event of faults on the DC side and disturbances in the AC grid, our systems are designed to withstand grid faults.
DC grid control
Our solutions enable stable voltage and power control in complex, multi-node HVDC systems.
Tailor-made hardware measurement solutions
Precise voltage and current measurement for reliable operation even under demanding conditions perfectly tailored to your application.
Power Electronics & Gate Driver Innovations
MOREOur high level of system integration and protection mechanisms enable high-performance and reliable inverter control. Our tailor-made prototypes help manufacturers to test their inverters faster and easier, optimize the control and bring the system to market readiness.
Customized prototypes
Individually developed inverter systems – tailor-made for rapid prototype development and specialized applications.
Specialized gate drivers
Gate drivers for special semiconductors such as dual-gate or reverse-conducting IGBTs with integrated short-circuit protection and precise timing.
Reliable converter design
Integrated protection through reliable fault detection and holistic coverter design – from cooling and parasitic inductance for SiC semiconductors to coverter control.
Measure. Understand. Fix.
MOREWhether current misdistributions, unexpected component failures or harmonic problems – we offer customised troubleshooting for existing systems. Our methods enable in-depth analyses and targeted optimisation to ensure that your power electronics work reliably and efficiently.
Recognising and understanding faults
Root-cause-oriented fault diagnosis – in-depth analysis instead of superficial symptom analysis. In our lab or on-site!
Converter Characterization
Complete characterisation of converters – We measure switching losses at all operating points, optimize gate resistances and test protective functions.
Harmonics analysis
Detect and specifically minimise disturbances in the power grid. In this way, we ensure grid quality and prevent undesirable effects on systems and consumers.
Lifetime analysis & thermal design
MOREWe refine models through thermal characterisation on prototypes and validate them with active power cycling tests under real load conditions. In this way, we ensure the reliability and competitiveness of your products throughout the entire design process.
We support you from the initial analysis through to final verification – for robust power electronics that deliver what they promise.
Lifetime estimation
Reliably predict the operating time of power semiconductor systems at an early stage of development. This enables optimized maintenance strategies, minimize failure risk, and avoid costly overdimensioning.
Power cycling tests
Active stress testing for evaluating the reliability of power electronics under realistic operating conditions. Our test benches can operate with realistic loss profiles (switching and conduction losses) and a superposition of multiple thermal cycles.
Thermal measurements & modelling
Precise measurement of thermal impedances for fault analysis, design optimization, or quality assurance in production. Whether early prototypes or field returns with degraded thermal paths, we accurately capture their thermal behavior for targeted analysis.
That’s the RKL
RKL GmbH
customers
in power electronics
in grid forming