Conference Agenda

This paper presents a resolution method to optimize a design problem in 3D-magnetostatic with nonlinear behavior. This method is based on an adjoint approach which is developed in 3D and uses volume integral equations. First, a method for computations of gradients using the adjoint method is presented. Then, in order to validate this method, the adjoint approach is used in an optimization process to design a simple 3D-magnetic circuit.

Wireless Power Transfer (WPT) technology has recently found application in Unmanned Aerial Vehicles (UAVs) to overcome their limited battery autonomy. However, adding an extra WPT system means extra weight to the UAV. This study presents a multi-objective optimization of the WPT system. The optimisation process considers both system efficiency and weight reduction as objective function. The optimization procedure uses a Genetic Algorithm (GA) algorithm, and is conducted using a meta-model build by combining a 3D FEM model and an electric circuit model.

Although metal additive manufacturing has matured into a technology that offers significant design freedom, it is still finding its place in the field of electrical machines. Its great potential lies in the printing of atypical electrical machines, such as transverse flux motors. Numerous successful attempts to print various soft magnetic materials can be found in the literature; however, high eddy current iron losses remain a challenge. While there are several methods to reduce the losses, they often do not respect the shape of the part or the operating frequencies. To address this, we propose using topological optimization methods, which are commonly used together with additive manufacturing in mechanical engineering, to find new structures that effectively reduce losses. The resulting designs must then be evaluated not only in terms of specific loss but also with respect to the input power required to achieve the desired magnetic flux density.

This article presents a new inverse algorithm based on magnetic tomography for fuel cell stack diagnostics. The aim is to determine the local internal resistivities of fuel cell stacks from external magnetic field measurements. The inverse problem is solved by minimizing the difference between the simulated magnetic field and the measured magnetic field. Sensitivities are calculated using the adjoint state method, and numerical results are presented shown on a 3D-fault.

The application of dielectric functionally graded insulation (d-FGI) under pulsed excitations significantly homogenizes the electric field distribution, thereby effectively improving the insulation performance. Nevertheless, a critical issue arises in designing d-FGI is that the optimal selection of the nonlinear nonuniform behavior of the dielectric parameters (conductivity/permittivity). For this purpose, in this paper a needle-plate dielectric model under pulsed excitations is considered for the optimization of the construction of the d-FGI by using genetic algorithm (GA). In specific, axisymmetric models in finite element analysis for a two-layer dielectric gradient and a multilayer dielectric gradient configuration are implemented. The nonlinear behaviors of the permittivity and the conductivity of the studied d-FGI are characterized by exponential functions of the electric field. The optimization results demonstrate the effectiveness of the proposed approach for the homogenization of the electric field in nonlinear nonuniform d-FGI under pulsed excitations.

In this work, a magneto-mechanical topology optimization method applied to the reduction of the harmonic content of magnetic

forces in the air-gap of a Permanent Magnet Synchronous Machine (PMSM) is proposed. This can help building innovative machines

with reduced noise and vibrations. The Virtual Work Method is used to compute the magnetic torque, the airgap force harmonics and

the sensitivity analysis needed in the optimization process. The novelty of this work is the use of non-linear mechanical constraints

in the optimization process that take into account the air gap around magnets, and help getting more realistic results.

This work addresses the topology optimization of a rotor of a hybrid-flux machine. The main challenge is handling many different material types (non-linear magnetic steel, air, DC conductors, and magnets with several orientations). Classical gradient-free topology optimization approaches are inapplicable due to the high dimensionality of the optimization space, and usual density-based methods fail to provide meaningful results by falling into uninteresting local optima. Therefore, two general and distinct methodologies are proposed: an extended density approach and a level-set method based on the topological derivative. Both methods result in meaningful designs that are analyzed and discussed, and recommendations are formulated.

In this paper, 3-Dimensional electric field calculation method is used to accurately compute the stray parameters of the converter valve in a complex environment. Initially, the electric field distribution of modular multilevel converter (MMC) valve and frequency domain characteristics of excitation in MMC system were analysed. Geometric equivalent calculations were performed on the key metallic components and insulating components that may cause electric field concentration in the MMC valve. Subsequently, the layout of the MMC valve in the valve hall was analysed, and the valve stray parameters calculations were performed based on the different positions of the valve towers in hall. Finally, the impact of mesh density on the calculated values of electric field strength was investigated. An optimization algorithm was used to determine the optimal grid size, which was then used to accurately compute the stray parameters of the MMC valve. The detailed calculation process and parameter calculations under different voltage excitations will be presented throughout the paper

The regular partition stator flux-switching permanent magnet (PS-FSPM) machine integrates both permanent magnets (PMs) and armature windings within a single stator, providing significant space utilization for both the inner and outer stators. However, the PMs on the inner stator limits torque enhancement to adjustments in the pole arc coefficient. To overcome the limitation of PS-FSPM machine, this paper proposed a novel PS-FSPM machine with a concave stator tooth structure and tangentially magnetized PMs arranged within the outer stator teeth (NN-SS-NN alternating pattern). The PMs on both the inner and outer stator sides exhibit flux-switching and flux-reverse effects, respectively. By exploiting the flux coupling between these two effects in the air gap, the amplitude of the air gap flux density is increased.

Based on the analytical model of permeability-magnetomotive force, the effects of flux switching effect and flux reversal effect are studied in this paper. Although the amplitude of the air gap flux density harmonics generated by these two effects are different, the harmonic orders remain consistent. Notably, the flux switching effect has a larger amplitude on the low-order harmonics, whereas the flux reversal effect has a higher high-order harmonic amplitude. Then, the equivalent magnetic circuit method is used to reveal the contribution of air gap flux density to the no-load flux linkage, and the effective coupling mechanism of the two effects in the total no-load flux linkage is verified. Subsequently, global optimization is performed using the Non-dominated Sorting Genetic Algorithm II (NSGA-II) to determine the optimal parameter values for both the regular and proposed machines. During the optimization process, the number of PMs is constrained to be identical for both two configurations.

Through finite element analysis,in comparison to the regular PS-FSPM machine, the output torque of the proposed machine is improved by 20.55%.

In this paper, a Novel Composite Soft Magnetic Material Based Three-Phase SCFCL (NCTFCL)is proposed to limit the transient short-circuit current in three-phase HVAC system under different conditions. Firstly, the topology and working principle of the NCTFCL is introduced, and its equivalent electromagnetic model is established. Secondly, The current limiting performance, volume and cost of NCTFCL are optimized based on RSM-MOGSA algorithm. Finally, the FEA simulation results demonstrate the effectiveness of the current limiting method and the structure of the proposed NCTFCL in this paper.

This paper introduces an innovative rectangular structured linear oscillating machine (LOM) featuring an innovative arrangement of permanent magnets (PMs) which are positioned on the mover. A Sinusoidal Magnet Arrangement (SMA) is chosen to minimize PM materials while ensuring the performance parameter, in terms of electromagnetic force (EM), remains unaffected. The main focus of the design is to reduce the cogging force and enhance the electromagnetic force to PM mass ratio. The optimization is accomplished by utilizing design-of-experiment (DOE) optimization for a linear actuator, along with the finite element method (FEM) and the Taguchi method. A multi-objective optimization approach is employed to refine the parameters of the linear actuator, focusing on the maximum force, the force-to-PM-weight ratio, and minimizing cogging force. By identifying the most effective parameters, an appropriate case with high sensitivity and accuracy is selected. The output parameters, like electromagnetic force and stroke of the proposed design and optimization approach, result very well while the design is simplest structured due utilization of a rectangular structured core part. The proposed design significantly reduces the cogging force to an exceptionally low level, enhancing performance and reliability.

This study highlights the impact of non-uniform airgap design on the performance of axial flux machines. Increased curvature of the airgap profile enhances the flux linkage between stator and rotor, yielding higher torque-production capability, while maintaining constant electric loading and outer dimensions. The results indicate an optimal point where the compromise between net flux and overall flux density in the airgap is minimized. The analysis also shows fluctuations in torque profile with higher airgap curvature, suggesting potential for improvement through control strategies.