Framework for efficient dynamic analysis applied to a tubular generator for suspension applications

This paper considers a slotless three-phase tubular permanent magnet generator located in an automotive suspension system for the application of vibration energy harvesting. A two-dimensional finite element method model of the harvester is produced and an experimental setup that contains the generator is constructed. Signal decomposition methods are applied to measured suspension displacement data and the resulting signal components are used as input for the model. Two approaches for signal decomposition are discussed, namely, the discrete Fourier transform and the continuous wavelet transform. The individual emf responses of the model are reconstructed to a single output, while a sideband prediction algorithm accounts for the non-linearities in the system. The simulation results are compared with the reference measurements conducted on the setup to determine the accuracy of each of the signal decomposition methods

Analysis of variable flux reluctance machines using hybrid analytical modelling

In this paper, an extended hybrid analytical modelling (HAM) technique is presented and applied to a variable flux reluctance machine (VFRM). The saturation phenomena in this machine is accounted by an iterative algorithm, while motion-integrated boundary conditions allow the torque estimation at different positions. The obtained results are further verified and have good agreement with finite element analysis

Analysis of motional eddy currents in the slitted stator core of an axial-flux permanent magnet machine

This article concerns the modeling and design of a slitted stator core for single-sided axial-flux permanent-magnet machine application. The stator core is specially designed to maximize the magnetic-flux density in the air gap and to minimize the eddy-current losses occurring at high rotational speeds. To reduce the effort needed for computing the motional eddy-current distribution in the presence of nonlinear material characteristics, a novel method is proposed. It combines the harmonic balance method, which is advantageous for simulating in the frequency domain the steady-state periodic response of a nonlinear system under harmonic excitation, together with a source description that introduces a complex magnetization that mimics the displacement of the permanent-magnet array. Following this method, time-domain distributions and losses can be reconstructed accurately with a low number of harmonics. A 3-D periodic model of the slotless axial-flux machine is built in the framework of isogeometric analysis (IGA) and a mixed formulation is employed, which relies on high-order Nédélec edge elements. The proposed model is embedded into a gradient-based optimization problem to determine the optimal shape of the slits in the stator core of the motor. This results in a novel cost-effective solution for improving the efficiency of axial-flux permanent-magnet machines

Design of an axial-flux permanent magnet machine for a solar-powered electric vehicle

This paper concerns the design optimization of two axial-flux permanent magnet (AFPM) machines, aimed to be used as a direct drive in-wheel motor for the propulsion of a solar-powered electric vehicle. The internal stator twin external rotor AFPM machine topology having either a distributed or toroidal stator winding configuration is investigated. The objective of the design optimization is to minimize the total volume of the machine. A gradient-based optimization algorithm is employed on a non-linear 2D equivalent motor model. The motor model consists of coupled electromagnetic and thermal models based on an Isogeometric Analysis (IGA) approach. A wide range of pole-pair numbers are optimized and compared in terms of power density and efficiency. Finally, the radius to evaluate the 2D model as a function of the pole-pair number is given, which minimizes the discrepancy with respect to the 3D finite element method (FEM)