Novel multi-stable electro-magneto-mechanical actuators based on variable remanent operating points of semi-hard- and hard-magnetic materials

• Applicant: Professor Dr.-Ing. Jürgen Weber
• Subject Area: Electrical Energy Systems, Power Management, Power Electronics, Electrical Machines and Drives ; Automation, Mechatronics, Control Systems, Intelligent Technical Systems, Robotics ; Engineering Design, Machine Elements, Product Development
• Term: from 2020 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 434232806

Electro-magneto-mechanical transformers are widely used in industrial and consumer applications. In fluid power applications, e. g. for valve drives, solenoids basing on the reluctance principle are primarily used. For these solenoids, various design and working principles have been established. These include mono-stable switching and proportional solenoids, which can only hold a position outside the stable position with a permanent supply of energy, as well as bi-stable switching solenoids, which only require energy during the switching operation. Multi-stable structures with any number of intermediate positions, which can be hold without energy supply, have not yet been researched. However, these actuator type has an enormous potential for significant increase of energy efficiency as well as of flexibility of current solutions. The operating principle is based on a partial magnetisation and re-magnetisation respectively of semi-hard- or hard-magnetic material by specific exploitation of the inner magnetic hysteresis behaviour.The overall aim of the planned project is a systematic research of novel multi-stable electro-magneto-mechanical structures. The detailed aims and contents of the submitted project are described in the following:Firstly, an extensive overview of semi-hard- and hard-magnetic materials with its detailed magnetic hysteresis behaviour is to be prepared. For this, the energy storage capability by inner magnetic hysteresis behaviour of a wide range of available semi-hard- and hard-magnetic materials is measured, investigated and modelled with hysteresis models from literature.Secondly, on this base, optimal material properties, magnetic circuits and control strategies for a best possible utilisation of the energy storage capability are to be identified. For this purpose, novel magnetic circuits for multi-stable solenoids are analytically researched on the base of the operating principle and compared regarding appropriate criteria. Promising variants are investigated by FE simulations with respect to their behaviour.Finally, the functionality of multi-stable solenoids is to be demonstrated. For this, a test bench is designed and built, in order to investigate promising semi-hard- and hard-magnetic materials as well as promising magnetic circuits. Furthermore, the functionality is to be verified with abstract and realistic loads.During the research period applied for, the basics of multi-stable electro-magneto-mechanical structures shall be researched so far that following projects can be focused on specific material development or on transferring the novel actuator principle into practical application.

• DFG Programme: Research Grants