Bernard Laporte

An approach to optimize winding design in linear induction motors

A method which mixes analytical and numerical approaches is developed to avoid finite elements computations in moving media. An optimization of a linear induction motor (LIM) is performed using two criteria: the efficiency; and the ratio of the thrust to the heat losses. Specific windings can be designed for LIMs which allow a significant improvement in their performance.

2-D adaptive mesh with movement

Adaptive meshes of electrical machines have to take into account the movement of the rotor. To combine accuracy and fast computation, nodes are added and canceled for any variation of the rotor position.

Mesh improvement in 2-D eddy-current problems

A mesh improvement technique in 2-D eddy-current problems is proposed. This technique uses an a posteriori error estimator issued from a local solution in the conducting region.

Generating rotor geometries by using a genetic method

The rotor of a synchronous variable reluctance machine is shaped by using genetic methods. In order to decrease the number of genes, macro-operators are tested.

An analysis of the rotational forces in the secondary of an electromagnetic pump

An analysis of the force density in the secondary of a linear induction motor is proposed. The Hodge-Helmholtz decomposition is applied, from which the force density is the sum of rotational and gradient terms, and the numerical details for the effective computation are done. An interpretation of the decomposition, useful for the case of a pumping application, is provided.

Equilibrium shape of a liquid metal subject to electromagnetic forces

The equilibrium shape of a conductive liquid metal submitted to electromagnetic forces is computed in the axisymmetric geometry and a comparison with experiments is performed. Meshing techniques are used to spare computation time.

An approximation for the air-slots of complex shaped motors

A method of approximation of the magnetostatic functional is investigated. It can be used for motors with a complex geometry such as the doubly salient switched reluctance machine with many teeth. This approximation allows one to simplify the meshing and then reduces the number of nodes. The obtained results are acceptable for the fluxes (less than 5%) and not so good for the torque (less than 25%). However this method can be used as a pre-processor for a geometrical optimization.

The computation of the lumped parameters of the saturated SRM

Applications such as the optimal control of the SRM require a fast lumped state model, which is widely studied in the literature. The method used to obtain the inductances from the FE field computation, in the saturated case, is known as the energy perturbation method. Here, the authors suggest both an improvement of this method and a strategy for building an adaptive map of the coenergy, which are required by the lumped model.