Electromagnetic structural-mechanical simulation of an axial flow generator

Sector: Electrical engineering/electronics, Energy supply, Machinery and plant engineeringSpecialist field: Electromagnetics, Multiphysics, Structural mechanics

Generators with direct drive are simpler, more compact and more robust, as they do not require a mechanical gearbox. The axial flux machines used by DDIS also achieve a considerably higher power density compared to conventional generators with radial electromagnetic flux.

Summary
Project Details
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Summary

Task

In the axial flow machines from DDIS, permanent magnets are used as central components, which are exposed to high loads due to their electromagnetic behaviour. Therefore, the electromagnetic force effect at different operating conditions should be determined and evaluated by means of numerical simulations.

Solution

The electromagnetic field distribution was calculated with Ansys Maxwell. A non-linear FEM simulation was carried out with Ansys Mechanical to determine the structural mechanical stress. The load transfer from the electromagnetic analysis was performed via a direct connection of the two analysis systems within Ansys Workbench.

Customer benefits

The results of the simulations provide essential findings for the further development of the generator. This includes insights into the conversion of mechanical power into electromagnetic energy, as well as the identification of the relevant parameters in terms of reliability and lifetime.

Project Details

Task

If direct drives are used as generators, this has the advantage that the electrical energy is generated without additional mechanical gears. This results in further advantages such as a simpler, more compact design with fewer mechanical components and thus greater robustness.

The French company DDIS has ensured even more compactness in the development of generators. Their innovation is the use of an axial flow machine. Compared to conventional generators with radial electromagnetic flux, they are not only more compact, but also enable systems with a much higher power density.

Permanent magnets are used as central components, which are exposed to high loads due to their electromagnetic behaviour. Therefore, the electromagnetic force effect at different operating conditions should be determined and evaluated by means of numerical simulations.

Exemplary distributions of magnetic flux density in the analysed axial flux generator.

Customer Benefit

The results of the simulations provide essential findings for the further development of the generator. Especially the interaction between electromagnetic and structural-mechanical behaviour deserves a closer look, because it enables

Insights into the conversion of mechanical power into electromagnetic energy,
Findings about a constructive optimal connection of the permanent magnets,
the identification of the relevant parameters in terms of reliability and lifetime when connecting the permanent magnets.

Solution

The electromagnetic field distribution in the axial flux generator was analyzed in Ansys Maxwell. Based on the transient motion of the system, magnetic field distributions are obtained as a function of the angle of rotation, which are definitive for the magnetic forces.

A non-linear FEM simulation with Ansys Mechanical was carried out to determine the structural-mechanical loading of the rotor and stator components. The load transfer from the electromagnetic analysis was performed via a direct connection of the two analysis systems within Ansys Workbench.

Within the scope of the project, different design variants and connection techniques were investigated. Based on the results of these investigations, proposals for improving the reliability and service life of the system could be developed.