Magnetic noise reduction of in-wheel permanent magnet synchronous motors for light-duty electric vehicles

This paper presents study of a multi-slice subdomain model (MS-SDM) for persistent low-frequency sound, in a wheel hub-mounted permanent magnet synchronous motor (WHM-PMSM) with a fractional-slot non-overlapping concentrated winding for a light-duty, fully electric vehicle applications. While this type of winding provides numerous potential benefits, it has also the largest magnetomotive force (MMF) distortion factor, which leads to the electro-vibro-acoustics production, unless additional machine design considerations are carried out. To minimize the magnetic noise level radiated by the PMSM, a skewing technique is targeted with consideration of the natural frequencies under a variable-speed-range analysis. To ensure the impact of the minimization technique used, magnetic force harmonics, along with acoustic sonograms, is computed by MS-SDM and verified by 3D finite element analysis. On the basis of the studied models, we derived and experimentally verified the optimized model with 5 dBA reduction in A-weighted sound power level by due to the choice of skew angle. In addition, we investigated whether or not the skewing slice number can be of importance on the vibro-acoustic objectives in the studied WHM-PMSM.Postprint (published version

A Planar Generator for a Wave Energy Converter

This article presents a permanent magnet planar translational generator which is able to exploit multiple modes of sea wave energy extraction. Linear electrical generators have recently been studied for the exploitation of sea wave energy, but, to the best of our knowledge, no synchronous planar translational generator has been proposed. In this article, to maximize the energy extraction, we have considered all the potential modes of motion due to wave excitation and included them within the mathematical model of the proposed system. The principle of operation of the generator can be summarized as follows: the moving part (translator) of the generator is driven from the sea waves and induces and electromotive force (EMF) on the windings mounted to the armature. The movement of the translator is 2-D and, therefore, all the movement modes of the wave, except heave, can be exploited. The proposed mathematical model includes the dynamic equations of the translator and the electric equations of the windings. The coupling parameters (inductances and fluxes) have been determined by finite element method analysis. Optimization of the device has been performed by considering both, the parameters of the electromagnetic circuit, and, the parameters associated with the stochastic features of the wave

Aspects of magnetisation and iron loss characteristics in switched-reluctance and permanent-magnet machines

In the first section, the magnetisation characteristics of the switched-reluctance motor are examined. Measurements have been carried out using both static and dynamic test methods. The test data has been compared with simulation results from analytical design programs and finite element models. The effects of mutual coupling on the magnetisation characteristics are investigated through measurement and simulation. Results show that the degree of mutual coupling is strongly dependent on the winding arrangement of the machine. In the next section, the difficulties in measuring the properties of permanent-magnet machines are discussed in detail, and solutions to common problems proposed. The measurement and analysis methods used for the switched-reluctance motor are further developed for analysis of permanent magnet machines. Techniques for determining the variation in synchronous reactances and permanent magnet flux are presented. Finite element simulations are used to show the variation of magnet flux under loading, a condition ignored in classical analysis methods. The final section discusses the analysis of magnetisation characteristics of electrical sheet steels. Comparison is made between measurements carried out on single sheet tester and Epstein square test rigs. The iron losses of a typical non-grain-orientated steel are measured under both sinusoidal and nonsinusoidal flux density conditions. The iron losses are shown to increase significantly when higher harmonic components are introduced to the flux density waveform. The difficulties in modelling the nonlinear iron loss characteristics of electrical steels are considered

LINEAR MOTOR FOR AIR VAPOR COMPRESSOR

This paper describes the modeling of linear motor compressor for use in household refrigerator compressor system. Literature review has been conducted for various types of linear motor technologies such as linear synchronous motor, linear induction motor, linear dc motor and also linear permanent magnet motor. Three proposed designs has been proposed which are tubular slotless linear motor using rectangular/trapezoidal permanent magnet with the magnet arrangement separately with mild steel and tubular slotless linear motor with rectangular permanent magnet. The designs are proposed due to force capability, simplicity and cost-effectiveness. Type of permanent magnet also will be taken into consideration. The characteristic and other element of the motor will be simulated using ANSYS software. The results in terms of air gap flux density and moving force have been presented. The most suitable design is chosen based on the higher average value of magnetic flux and force. In addition, this project is mainly focused on the selection of the design from the three proposed design that have been proposed. In future work, the selected design then can undergo design optimization to prove that the design can increase the efficiency of the compressor and thus reduce the power consumption