SpinDrive for Fusion Power
SpinDrive has solved various technical problems in the field of high-speed electrical machines with its magnetic bearing solutions. The company has top-of-world know-how in active magnetic bearing (AMB) technology combined with extensive knowledge of high-speed electrical machines.
Fusion reactors are the next major step in energy generation that will allow us to mitigate climate change and obtain enormous sources of green energy. The important aspect is that such a source is not subjected to day and night energy generation variation or wind conditions. With all its benefits the complexity of the solution is high and to make it successful a great number of technologies are used. One of them is magnetic bearings.
Finland-Czech Republic relations opened the door for collaboration
Brno University of Technology (Czech Republic) has been providing their students with exchanging studying opportunities for many years. They have benefited from each other’s expertise and looked for opportunities to cooperate on research and business subjects.
When Brno University was arranging a consortium, they realized there was a need for active magnetic bearing expertise. SpinDrive was known to them for its world-class expertise in magnetic bearing solutions. Thus, the collaboration between Brno University and SpinDrive kicked-off with the project funded by the Technology Agency of the Czech Republic (TACR). SpinDrive became a partner in development of the high-speed technology for the helium Primary Heat Transfer System (PHTS) for fusion reactor.
The project is run in cooperation with the Czech industrial companies, who are specialists in the helium turbocirculator systems, electrical machine manufacturing with expertise with multimegawatt, high-voltage electrical machine production. Consortium partners were the suppliers to ITER, first European fusion reactor. SpinDrive is responsible for the development, testing and supply of the active magnetic bearing system for this challenging application.
The goal of the project is to acquire the unique know-how of advanced technology and build the prototypes required for the DEMO. The DEMOnstration power plant, DEMO, will be ITER’s successor, which is the first European fusion reactor. One of the milestones of the project is to design and build 350 kW, 6 kV high-speed machine to test the main concepts, which will be a separate product, where SpinDrive active magnetic bearing system will be used.
Figure 1. Free-free modes of the rotor for helium turbocirculator
Magnetic Bearings Made Everything Possible
Traditional ball bearings are very limited in many areas, e.g. they cannot stand high temperatures or harsh environments. In this project, traditional ball bearings were not capable of supporting the machine. SpinDrive’s magnetic bearings made everything possible. Some of the major benefits of using magnetic bearings include higher system efficiency, low material consumption, maintenance-freedom, and the ability to work under critical working conditions.
This is the first machine of its kind, and the project requires a flexible approach with a fast evaluation of different design options. The core competence of SpinDrive where we can evaluate options in a fast manner, propose different topologies, and adjust the design to the needs of the system matches with the needs of the DEMO perfectly.
Figure 2: Magnetic bearing system in high-speed multi-megawatt machine
Major challenges in this project
Turbines are naturally high-speed rotating machines where bearing technology is an essential part. However, high-temperature requirements make it challenging for conventional types of bearings to survive long enough. Moreover, it also adds up the maintenance cost. AMBs can withstand up to 220°C and with special arrangements, even several hundreds of degrees Celsius are the appealing solution in this application.
Another challenge in the energy conversion chain is a generator, which optimally should rotate at the same speed as the turbine. Gearboxes that would allow adjusting the speed take plenty of space, increase maintenance needs and reduce efficiency. AMBs enable direct-driven high-speed generator and eliminate the need for a gearbox. or the generator, AMB benefits such as maintenance-free operation and increased efficiency due to the absence of friction are still applied and only the temperature limitations might be lower.
Solutions provided by SpinDrive
The project kicked off with a thorough planning meetings by the Brno University of Technology, Czech industrial partners, and SpinDrive. With a good understanding of the needs and goals, SpinDrive provided the design of magnetic bearings actuators, sensors, and the selection of safety bearings in this project.
The appealing property of AMBs is that the actuators can be isolated from the process by applying the canned solution. In that way, the pumping system can be hermetic which significantly reduces the mechanical complexity as there is no need for labyrinth seals of similar solutions.
SpinDrive was also responsible for evaluating the rotor dynamics, designing the control systems, and integrating them into upper-level PLC using Magnetic Bearing Controller Magma® X800.
Figure 3. Magma® X800 Magnetic Bearing Controller
Results achieved by SpinDrive
With the help of active communication and mutual understanding, the project already achieved great results. “We are very pleased with SpinDrive’s expertise and professional work throughout the project. We enjoyed the flexibility and the fast pace of SpinDrive. On the technical side, SpinDrive provided a bearing solution that can operate without maintenance for years in harsh and high-temperature environments.” says Project Manager Ing. Jan Bárta, Ph.D., Assistant Professor at Brno University of Technology.
Hitting all the targets of this project does not necessarily mean the end of the project. After this successful project, the collaboration between Czech industrial partners, Brno University of Technology and SpinDrive will be continued to explore the opportunities in fusion power.