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This paper presents a two-dimensional analytical model for brushless double-rotor flux-switching permanent magnet machines (BDRPFSPMM) with yokeless stator recognized as a type of partitioned-structure flux-switching permanent magnet that is an appropriate machine to be employed as the electric motor in industry. The most salient advantages of the proposed machine are low iron loss due to volume of iron in stator and high space of stator slot for winding. The radial and tangential components of the magnetic flux density due to permanent magnets and armature currents in each active domain of the machine, electromagnetic torque, self- and mutual inductance, unbalanced magnetic force (UMF), and local traction are calculated based on the subdomain method. Teethes on both rotor and stator structures are effective on magnetic quantities, so interactions of rotor and stator saliency are considered. The method is general for the magnetic field calculation with any combination of rotor- and stator-pole number. To validate the proposed model, the analytical outputs are compared with those obtained from the finite element method (FEM). [ABSTRACT FROM AUTHOR]

This paper is the first that proposes an extended hybrid analytical method (HAM) based on a two-dimensional (2-D) coupling between the semi-analytical Maxwell-Fourier analysis and finite-element method (FEM) in polar coordinates. The proposed model is applied to any rotating electrical machines. The main objective of this paper is to establish the magnetic field solution in the whole machine by coupling an exact analytical model (AM), proposed for all regions having relative magnetic permeability equal to unity, with a FEM in ferromagnetic regions. The AM and FEM are coupled in both directions (r , θ) in the edge separating teeth regions and all its adjacent regions by applied boundary conditions (BCs). The developed HAM gives accurate results on the magnetic flux density distribution and the cogging torque whatever the operating conditions, the magnetic or geometric parameters. All results obtained give very satisfactory agreement with 2-D finite-element analysis (FEA). [ABSTRACT FROM AUTHOR]

In this paper, a variable reluctance generator with segmental stator utilizing an assisted DC field for variable speed applications is proposed. In this work, analytical design, magnetic field analysis, and Parametric Sensitivity Analysis of the proposed machine are presented. The stator of suggested configuration, in addition to the distributed phase windings, is included the distributed assisted dc field coils, which are responsible for producing an adjustable magnetic flux in the generator. The segmental stator, the controllability of magnetic flux and generated voltage are the prominent features of the presented generator. Maintenance-free and easy accessibility of each stator segment due to utilizing the segmental stator, and high reliability due to the absence of brush and winding on the rotor is other features of the proposed machine. Finally, the Field Analysis using the finite element method is performed to verify the analytical design and sensitivity analysis. The results obtained from the FE analysis confirm the analytical design and the controllability of magnetic flux and generated voltage for the proposed configuration. [ABSTRACT FROM AUTHOR]

This paper presents an evaluation of the current technologies and future requirements of electrical machine in automotive. First, a comparative of ten different electrical machines based on the market available electrical vehicles and hybrid electrical vehicles is made. The aim of the comparison is to evaluate the different electrical machine topologies, structure, operation conditions, and performance. The future design requirements of electrical machine in automotive are presented and several state-of-art electrical machine design techniques have been explored and studied by employing them in the compared ten machines. The conclusion of this work shows that permanent magnet topologies have the highest performance among the different electrical machine topologies and have the potential to meet the future requirements. In addition, aggressive cooling methods, i.e., spray, dripping, semi- or fully flooded, are needed to allow electrical machines to operate with the required power density target. Finally, the design to recycle concept shows the potential to be implemented in future electrical machines with little or no sacrifice of the performance. [ABSTRACT FROM AUTHOR]

Outer rotor switched flux machines (ORSFM) provide crucial role in high-speed applications. The flux excitation sources are enclosed in the stator, resulting in a totally free and passive rotor, making the switched flux machine more appropriate for high-speed and industrial applications. Outer rotor flux switching machine for in-wheel and direct drive application is introduced, requiring mechanical gear as they are proficient in high torque at low speed. Additionally, multiphase flux switching machines inherit the benefits of traditional FSPM machines as well as the capabilities of multiphase machines, e.g. high torque density, high fault-tolerant capability, and low torque pulsations. In this paper, a five-phase outer rotor wound field excitation flux switching machine with 17-P/10-slot and 24-P/10-slot is discussed. Various performance parameters like operating principle, flux linkage, self and mutual inductance, cogging torque, back electromotive force, harmonics, air gap flux density, and average electromagnetic torque are analysed. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to introduce a complete wind conversion system based on a hybrid excitation synchronous generator (HESG) for large-scale 1.5 MW, grid-connected wind turbines. The proposed architecture should be tested under realistic operating conditions. However, for this power, setting up an experimental test bench would require exceptional funding for the laboratory and a great expertise. So, instead, advanced software simulation tools are used. In this work, an integrated near-realistic simulation model is developed. Both, the harmonics of the generator and the aerodynamics of the wind turbine are modeled. To ensure an optimal operating of the aerogenerator, a CRONE robust control approach is adopted. It is used for the generator's velocity loop controller and for the pitch control loop. Comparisons with a robust H∞ controller and a PI-based fuzzy controller are presented. Both control loops are tested under severe loads and stochastic wind profile. It is shown that an efficient control is achieved. Then, two scaled down power electronic interfaces using both, multilevel and conventional inverters, are implemented and investigated in terms of cost and performance. A Cascade H-bridge three-level inverter is chosen as it offers a good total harmonic distortion (THD) using a simple modulation technique without an extra filter to connect to the grid. Results show that the proposed architecture can be used to conduct performances-based comparisons to similar wind systems based on other types of generators such as permanent magnets synchronous generators and doubly fed induction generators. [ABSTRACT FROM AUTHOR]

This paper introduces a novel technique to maintain the operation of the five-phase permanent magnet synchronous motor post the failure in two phases of the motor and post the failure of the speed sensor occurs simultaneously. To achieve that, firstly, a fault-tolerant control (FTC) technique is implemented. The FTC is based on implementing two new space vector pulse width modulation (SVPWM) besides using field-oriented control to minimize the torque ripple and to maintain the performance post the two-phase failure. Secondly, algorithms are proposed to obtain the saliency position post the failure of the two phases. The technique is based on measuring the transient response of the motor's remaining healthy currents due to the inverter switching actions. These switching actions are related to the PWM signals obtained from the new SVPWM techniques implemented post the two-phase failure. The whole control technique post the failures is very simple to implement. Simulation results are provided to verify the reliability of the proposed control technique to maintain the performance of the five-phase motor drive post the failure in the two phases and the failure of the speed sensor occurred simultaneously without compromising the preperformance (maintain the torque ripple less than 3.6% and 3.4% post the failure). Moreover, the results have demonstrated the ability for the whole system to work effectively over a wide speed range and load conditions post the failure. [ABSTRACT FROM AUTHOR]

The present article proposes a nonlinear optimal control approach for permanent magnet AC machines with non-sinusoidal back electromotive force being fed by three-phase inverters. Such AC machines are also known as permanent magnet brushless DC motors (PMBLDC) and find use in several traction and actuation systems. First, by applying an extended park transformation, the dynamic model of the electric motor is expressed in the dq rotating reference frame. Next, the nonlinear dynamic model of the electric motor undergoes approximate linearization around a temporary operating point which is recomputed at each iteration of the control method. This temporary operating point is defined by the present value of the electric motor's state vector and by the last sampled value of the machine's control inputs vector. The linearization relies on Taylor series expansion and on the calculation of the system's Jacobian matrices. For the approximately linearized model of the electric motor, an H-infinity feedback controller is designed. This controller stands for the solution of the nonlinear optimal control problem for the considered type of electric motor under model uncertainty and external perturbations. For the computation of the controller's feedback gains, an algebraic Riccati equation is iteratively solved at each time-step of the control scheme. The global asymptotic stability properties of the control scheme are proven through Lyapunov analysis. Finally, the nonlinear optimal control method is compared against flatness-based control and sliding-mode control. [ABSTRACT FROM AUTHOR]

This research work is aimed at the modification of in-wheel switched reluctance motor (Outer rotor-type SRM) with minimized torque ripple for electric vehicles. The geometry of stator and rotor poles affects the torque. Variation in the stator and rotor pole geometry causes change in the torque profile. To reduce the torque ripple and to increase the average torque, modification in the stator and rotor pole shoes is presented in this article. The stator and rotor pole shoes with notches and projections are proposed with the objective of minimization of torque ripple and maximization of average torque. Electromagnetic analysis of conventional and modified in-wheel SRM is done with computer-aided design software MagNet 7.1.1. From the finite element analysis results, the average torque and torque ripple values are derived. Prototype of 8/6, 1000 W in-wheel SRM with the notches and projections is fabricated. Experimentation is performed on the fabricated machine to measure the magnetic flux linkage, current and speed characteristics of the proposed in-wheel SRM. The precise determination of magnetic flux characteristics is significant to check the machine design and to accurately predict the action of modified in-wheel SRM. Static modeling results of the fabricated machine were coherent with the experimental values. [ABSTRACT FROM AUTHOR]

This paper describes the structural behavior of a permanent magnet synchronous machine (PMSM), used to propel a light electric vehicle, namely an electric scooter. The motor's topology is with outer rotor (in-wheel motor). Since the rotor and the stator iron cores are under electromagnetic force influence, both parts have their own influence on the overall behavior of the PMSM, and for this reason, here they will be separately analyzed. This analysis is carried out in order to observe the mode shapes of the PMSMS, involved by radial forces. These mode shapes represent, in part, the image of the vibration and noise produced by the PMSM. The analysis is carried out by using LMS Virtual.Lab software; with this tool, based on appropriate discretization, one can investigate, on a larger frequency range, the mode shapes of the PMSM' structure. Next, the experimental mode shapes are experimentally evaluated by performing the so-called impact testing. The comparison of the numerical and experimental results depicts the consistency of the research and indicates the behavior of the studied structure in specific operating conditions. [ABSTRACT FROM AUTHOR]

The paper details the design optimisation and comparison of two different rare-earth permanent magnet flux-switching machines (PM-FSMs)—12/10 and 12/14—for geared medium-speed wind power generators. The focus is mainly on trade-offs in the performance of these two machines at 10 kW and 3 MW power levels, with highlights on the multi-objective evolutionary optimal performance of small-scale to utility-scale wind turbines. Based on finite element analyses (FEA) and multi-objective design optimisation (MDO), different streams of optimal solutions are obtained and studied. As an indication of the potentials of the proposed PM-FSM wind generators, even for rare-earth-free concepts, the 3 MW designs portray significantly improved torque density thanks to the fixed rotor speed considered at both power levels, and also, smaller torque ripple profiles are conceived due to differences in the calculated saliency ratios, compared to their 10 kW designs. Another finding is based on the nonlinearity of the MDO process on the objective performance of the different machine topologies at the different power levels, which was necessitated by the optimal behaviour of certain design variables such as the split ratio, slot opening width, current density and PM width. Uncharacteristically, the results also reveal possibilities for higher efficiency in 12/14 machines compared to the 12/10 machines, due to positive relationships approximated from general evaluations conceived in the MDO search space in the former, for the split ratio and current density when plotted against the active mass. Lastly, a comparison between 2-D static and 3-D transient FEA processes on some selected benchmarks displayed good agreement. [ABSTRACT FROM AUTHOR]

This paper proposes a new topology for a brushless wound rotor synchronous machine (BL-WRSM) using a specially designed stator winding supplied through a single three-phase inverter. In this topology, a special stator winding, which comprises of two sets of series-connected windings with an unequal number of turns, is used to generate an additional spatial sub-harmonic component in the stator magneto-motive force (MMF). This additional sub-harmonic MMF (SH-MMF) component is utilized for exciting the field winding of the BL-WRSM. The advantage of the proposed brushless topology is the use of a single inverter compared to a dual inverter used in the existing dual inverter BL-WRSM. For the rotor, there are two separate windings: (1) harmonic winding and (2) field winding. Both the harmonic and field windings are connected in parallel with each other through a rotating rectifier. The additional SH-MMF component generates a rotating air-gap magnetic field, which induces the voltage in the harmonic winding. This induced voltage is then rectified and used to supply a dc current to the field winding. A 2-D finite element analysis is performed to analyze and verify the operating principle of this new BL-WRSM. [ABSTRACT FROM AUTHOR]

The aim of this paper is to present a new method to generate stator currents supplying a surface permanent magnets synchronous motor (SPMSM) presenting an asymmetry of the stator windings. This asymmetry may be due to a lack of turns in one of the stator windings or to an inter-turns short circuit. An analytical model of the SPMSM is developed to calculate the current which allows minimizing the torque ripple generated by the asymmetry. This model is based on the combination of the space harmonics of the flux densities of stator and rotor for the generation of the torque. Our study leads to define a stator inverse current system able to compensate the harmonic torque component at the double of the supply frequency. In the experimental tests, several cases of supply were applied and the results confirmed those obtained by the analytical study essentially concerning the amplitude of the inverse current. [ABSTRACT FROM AUTHOR]

This paper deals with double saliency switched reluctance motor for automotive application by offering simultaneously a design solution to the drawbacks of torque ripples and emitted noise caused by the important radial efforts. The work concerns the optimization of the motor structure, the main objectives is the reduction of the first harmonics of torque and radial force applied on the stator teeth. This geometric optimization is performed on operating points where the instantaneous computation of supply current is taken into account to resolve simultaneously both problems. This operating point is defined as torque–speed point by considering the instantaneous characteristics of the machine when the steady state is established. [ABSTRACT FROM AUTHOR]