Yuki Hidaka

Topology Optimization Method Based on On–Off Method and Level Set Approach

This paper proposes a two-step method for topology optimization, in which after global search is performed by the on-off method, and then local search is carried out by the level set approach. The genetic and gradient-based algorithms are employed for the former and latter optimizations, respectively. This present method is applied to two numerical examples; topology optimizations of a magnetic shield system and interior permanent magnetic motor. It is shown that this present method can find solutions with better performances in comparison with the conventional on-off method.

Robust Optimization Considering Probabilistic Magnetic Degradation

This paper presents robust topology optimization of electromagnetic machines by considering the magnetic degradation caused by mechanical and thermal stresses in punching, shrinking fitting, and other manufacturing processes. The topology optimization is performed using two methods: one is the robust genetic algorithm in which random noises are added to the magnetic characteristic parameters and the other takes the deviations in the objective and constraint functions due to the degradation into account. These methods are applied to optimization of the flux barrier shapes in an interior permanent magnetic motor to find that one can successfully realize robust design.

Topology Optimization of Synchronous Reluctance Motors Considering Localized Magnetic Degradation Caused by Punching

The magnetic characteristic of magnetic steel sheets used for rotating machines can be degraded by punching, cutting, or other manufacturing process. This degradation damages the performances of motors. This paper presents topology optimization of rotating machines considering the localized magnetic degradation caused by punching process. It is shown that the optimized synchronous reluctance motors obtained by this method satisfy the torque constraint under the existence of the magnetic degradation.

Topology optimization of rotating machine rotors considering localized magnetic degradation caused in manufacturing process

This paper presents topology optimization of rotating machine rotors considering localized magnetic degradation in rotor and stator cores caused by the manufacturing process. On the basis of experimental observation, magnetic reluctivity is assumed to exponentially decay as approaching to the processed surfaces. The present topology optimization seeks for optimal rotor shapes which are robust against the material degradation.

Three-dimensional shape optimization of claw-pole motors

This paper presents three-dimensional shape optimization of claw-pole motors. The claw-pole shape is determined from the binary state of hexahedral cells. The cell states are optimized to maximize induced voltage and minimize the field current using micro-genetic algorithm. The optimization is successfully carried out without time-consuming mesh generation.

Stochastic topology optimization based on level-set method

Purpose – Conventional level-set method tends to fall into local optima because optimization is conducted based on gradient method. The purpose of this paper is to develop a novel topology optimization in which simulated annealing (SA) is introduced to overcome the difficulties in level-set method. Design/methodology/approach – Level-set based topology optimization for two-dimensional optimization problem. Findings – It is shown in the numerical examples, where conventional and present methods are applied to shape optimization of ferrite inductor and Interior Permanent Magnetic (IPM)-motor, the present method can find solutions with better performance than those obtained by the conventional method. Originality/value – SA is introduced to improve the search performances of level-set method.