Model-based control of multi-stable electro-magneto-mechanical actuators for precise and energy-efficient adjustment of remanent operating points

• 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: since 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 434232806

Multi-stable electro-magneto-mechanical transducers are a new field of research and combine the continuous adjustment of proportional solenoids with the energy efficiency of polarised magnetic circuits. The DFG project ‘Novel multi-stable electro-magneto-mechanical actuators based on variable remanent operating points of semi-hard- and hard-magnetic materials’ has laid extensive foundations for this. The approach consists of a specific exploitation of the inner hysteresis behaviour of semi-hard and hard magnetic materials for setting remaining magnetic fluxes, magnetic forces or armature positions, which are hold without further power supply. Various demonstrators have been used to successfully show how such remanent operating points can be set. Nevertheless, the work has revealed challenges that require the DFG project to be continued. These include the high polarisation energy needed to set remanent operating points as well as the influence and consideration of unknown load forces and temperature-dependent material properties. In principle, these issues can be addressed with suitable control strategies. The overarching aim of the planned research project is an optimum control of multi-stable solenoids, in order to be able to set remanent operating points precisely and energy-efficiently. The approach consists of model-based control using a hysteresis model. In detail, the following objectives and contents arise for the proposed project: In the first step, the hysteresis behaviour of promising semi-hard and hard magnetic materials will be further detailed in preparation for model-based control concepts. For this purpose, typical operating point sequences (higher order reversal curves) and the temperature-dependent behaviour are measured. The knowledge gained is used to further develop and parameterise the hysteresis modelling. On this basis, model-based control strategies are designed, simulatively analysed and promising ones identified in the second step. The focus is on precise and energy-efficient adjustment of the remanent operating point, taking the history into account. This generally requires information on the current and past operating points, which is made accessible with the help of suitable sensors and observer methods. In the final step, the control concepts developed are verified using measurements. The concepts are first extensively analysed and further developed at room temperature using existing demonstrators. The work will be extended to various actuator temperatures, in order to demonstrate the functionality under realistic boundary conditions. At the end, it is investigated how the power density can be increased by optimum matching of actuator design and control.

• DFG Programme: Research Grants