Affiliations: [a] Department of Electrical Engineering, University of
Pavia, Pavia, Italy
Correspondence:
[*]
Address for correspondence: Prof. Paolo Di Barba, PhD,
Department of Electrical Engineering, University of Pavia, Via Ferrata 1,
I-27100 Pavia, Italy. Tel.: +39 0382 985250; Fax: +39 0382 422276; E-mail:
paolo.dibarba@unipv.it
Abstract: Classical microeconomics and game theory offer a conceptual frame to
solve a design problem, characterized by multiple objective functions in mutual
conflict. This viewpoint is largely accepted for the design of high-tech
products as seen in aerospace engineering. However, for long-established
products – like electromechanical and electromagnetic devices – the ongoing
evolution in design strategies is not fully influenced by the impact of new
design methodologies and software facilities. With this rationale, the shape
design of a permanent-magnet three-phase motor is considered as an example of
small actuator for house appliances; the analysis of the magnetic field is
based on a finite-element model of the device. The design goal is to identify
the magnet shape, such that the cogging torque of the motor is minimum for a
given value of radial induction at the air-gap. More generally, the problem is
cast in terms of multiobjective design: find the set of magnet shapes such that
the torque is minimum and the induction is maximum, subject to the given
constraints. Solutions in terms of Pareto front and Nash equilibrium are
obtained by means of an evolutionary algorithm; during the automated search,
discrete-valued design variables were considered, for the sake of a realistic
design. The paper shows that the application of multi-objective optimisation in
electromechanics gives a powerful design tool. Requirements in terms of timing
and facilities are compatible with the resources of a research-and-development
(R&D) centre of an industrial company in the area of electrical
engineering.
