When a client developing high-temperature fuel cells, known as SOFC, powered by hydrogen or natural gas, approached Eletech, the R&D hub of the Elemaster Group, standard converters were theoretically available. In practice, however, none could be integrated into the client’s system without a level of modification that made them unsuitable.
Fuel cells produce electricity through an electrochemical process, but that process can degrade if the current drawn from the cell is not managed with extreme precision. For this reason, Eletech chose to develop a charge converter from the ground up, designed specifically around the behaviour of that particular energy source and around an efficiency requirement that left almost no room for error.
A converter designed around a specific fuel cell
Fuel cells operate by using hydrogen or natural gas at high temperature and converting that reaction directly into electricity. To transfer this power to the grid, Eletech developed a custom charge converter: a 10kW module that can be connected in parallel inside containers scaling to 50-100kW, feeding a standard inverter of the type commonly used in photovoltaic systems.
The solution was not adapted from an existing catalogue product. The collaboration began because the client, focused on the development of the fuel cell itself, needed an external team capable of designing a product according to specification and integrating it fully into the apparatus. This meant working on both the mechanical and electronic integration of the converter, as well as managing the certification process.
Stability as the main engineering challenge
The main engineering difficulty lies in stability. If the current drawn from a fuel cell is unstable, the cell degrades more rapidly. The converter therefore needs to maintain a very precise and steady operating point during long and continuous operating cycles, while remaining reliable enough to keep generating current without interruption.
At the same time, the converter must adapt as the fuel cell’s own performance changes over the course of its lifetime. It has to follow that evolution and extract the maximum amount of energy that the cell is still able to deliver.
The client’s target was clear: electronic efficiency above 97%, leaving a margin of barely 3% for losses.
“It’s quite challenging to guarantee that efficiency across every operating point, for the entire life of the product”, says Eletech’s Technical Director Marco Breviario
Choosing Gallium Nitride to reach the target
Achieving this level of efficiency required the use of components that are still relatively new in this field. The 10kW converter operates with input voltages between 50 and 105V, drawing up to 140A, and regulates output between 700 and 810V.
To meet these electrical requirements while maintaining the required efficiency, Eletech selected Gallium Nitride devices instead of traditional MOSFETs. GaN devices switch faster and allow smaller, denser designs. This made it possible to create a module tailored for custom integration into the client’s apparatus, rather than forcing the system to adapt to a standardised footprint.
One converter for different fuels and applications
The application logic was intentionally designed to be flexible, in line with a fuel cell technology capable of operating with hydrogen, biogas or natural gas.
Depending on the configuration, the system can convert fuel into electricity locally, draw natural gas from the grid or operate in a way similar to a battery with its own fuel reservoir. Target applications include power supply for data centres and backup systems in regions where blackouts are frequent. These blackouts may be caused by seasonal peaks in demand, such as air conditioning during summer, or by grids that are not reliable from the outset.
Because the converter is fully custom, including mechanical integration and certification, the client can offer a single, fully engineered product worldwide instead of adapting it market by market.
Compressing the testing cycle
Meeting the certification requirements imposed by international standards for a first-of-its-kind design also required a faster way to identify and solve problems.
Eletech operates its own in-house certification laboratory alongside functional testing. This allows issues identified by R&D to be addressed without sending the unit to an external laboratory and waiting for it to return. According to the company, this setup reduces testing time by roughly one third compared with relying on an external lab, transforming what would otherwise be a week-long loop between design and test into a single day.
Why the complexity matters
For Federico Gualdi, System Engineering at Eletech, the work carried out on this converter is connected to a broader technological direction.
“Hydrogen is an energy vector with the potential to drive the energy transition we need. It still has limitations, tied to material costs and to the energy cost of producing it.”
The expertise developed around stability and efficiency for this converter can be transferred directly to other hydrogen technologies and to battery systems within Eletech’s Power and Energy practice. In this way, the know-how created for a single 10kW module can scale horizontally across a market segment that is still defining its own electronics.
What began as a single client’s request is therefore helping shape how Eletech approaches the next project.