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This paper aims to investigate the performance of two novel direct torque control (DTC) schemes dedicated to three-switch three-phase inverter (B3-VSI), also called delta inverter, fed induction motor (IM) drives.

The principle of operation of the B3-VSI-fed IM drive is recalled in a first step. Then, the basis of both proposed DTC strategies is presented. The first DTC scheme considers a subdivision of the stationary plane into three sectors and the application of the intrinsic as well as virtual voltage vectors to achieve the control combinations. While, the second DTC scheme considers a subdivision of the stationary plane into six sectors and a limitation of the voltage vectors incorporated in the look-up table to the three intrinsic ones.

Simulation and experimental results have revealed that, under steady-state operation and transient conditions, the harmonic content of the IM stator phase currents is lower in the case of the DTC2 strategy, resulting in a lower ripple of electromagnetic torque. Furthermore, it has led to a quasi-circular shape of the locus described by the stator flux vector in the stationary plane.

This work should be extended to the synthesis and performance analysis of a new DTC strategy for B3-VSI-fed IM drive, which emulates the operation of the conventional six-switch three-phase inverter-fed IM drive.

The limitation associated with the reduced number of the intrinsic voltage vectors generated by the B3-VSI has been eradicated, thanks to the suitable synthesis of the look-up table incorporated in the DTC scheme.

The purpose of this paper is to propose an approach to improve the torque production capability of fractional slot permanent magnet machines.

Following an analytical formulation of the electromagnetic torque, two optimization criteria are selected: the maximization of the average torque and the minimization of the torque ripple. For the sake of a simple analysis, the proposed approach assumes that the effects of the machine circumferential and radial parameters, on the torque production capability, are almost decoupled, so that their sizing optimization could be carried out separately.

The torque production capability of the optimized machine has been confirmed by finite element analysis, which confirms the appropriateness of the proposed sizing approach.

The obtained results should be validated by experiments carried out on a prototype.

The proposed approach has been carried out thanks to the introduction of the torque average value and ripple amplitude iso‐2D curves for circumferential parameters and iso‐3D surfaces for radial ones.

This paper aims at the improvement of the cost‐effectiveness of brushless DC motor (BDCM) drives integrated in electric and hybrid propulsion systems.

The cost‐effectiveness improvement is gained through the reduction of the topology of the inverter in the armature which turns to have two legs (four switches) rather than three legs (six switches) in conventional inverters. This has been made possible thanks to the availability of the battery pack in automotive applications.

It has been found that the four‐switch three‐phase inverter (FSTPI) fed BDCM drive has almost the same performance as the six‐switch three‐phase inverter (SSTPI) fed BDCM.

This works should be extended by an experimental validation of the established results.

The reduction of the topology of the inverter in the armature of the BDCM opens up crucial cost benefits especially in large‐scale production industries, such as the automotive one.

The implementation of a simple self‐control strategy in a FSTPI fed BDCM drive yields almost the same dynamic and steady state performance as those obtained by a SSTPI fed BDCM drive. An analytical assessment of the steady state features of the FSTPI‐fed BDCM drive has been confirmed by simulation.

The purpose of this paper is to analyze the performance of a new direct torque control (DTC) strategy dedicated to four‐switch three‐phase inverter (FSTPI)‐fed induction motor drives with extended speed range.

The approach is based on the synthesis of a suitable vector selection table in order to reduce torque ripple. The performance analysis is carried out based on three criteria: the total harmonic distortion; the switching loss factor; and the quality factor.

It has been clearly shown that the introduced DTC strategy offers high performance during both transient and steady‐state operations of the FSTPI‐fed induction motor drive, which are almost the same as those yielded by the Takahashi DTC strategy implemented in the same motor fed by a conventional six‐switch three‐phase inverter (SSTPI).

The work should be extended by an experimental validation of the simulation results.

The established results open up crucial benefits from the point of view of cost‐effectiveness and volume‐compactness of induction motor drives especially in large‐scale industries such as the automotive, where electric and hybrid propulsion systems are currently regarded as an interesting alternative to substitute or to assist the thermal propulsion systems.

The paper presents the implementation of a dedicated DTC strategy in FSTPI‐fed induction motor drives with extended speed range. The proposed DTC strategy offers interesting performance compared with that yielded by the Takahashi DTC strategy implemented in the same motor fed by an SSTPI.

The purpose of this paper is to compare the study between two topologies of fractional-slot permanent-magnet machines such that: double-layer topology and single-layer one. The comparison considers the assessment of the iron loss in the laminated cores of the magnetic circuit as well as in the permanent magnets (PMs) for constant torque and flux weakening ranges.

The investigation of the hysteresis and eddy-current loss has been carried out using 2D transient FEA models.

It has been found that the stator iron losses are almost the same for both topologies. Whereas, the single-layer topology is penalized by higher iron loss especially the eddy-current ones taking place in the PMs. This is due to their denser harmonic content of the armature air gap MMF spatial repartition.

The analysis of the iron loss maps in different parts of each machine including stator and rotor laminations as well as the PMs, in one hand, and the investigation of their variation with respect to the speed, in the other hand, represent the major contribution of this work.

The purpose of this paper is to propose an approach to teach to post‐graduate students the basis of hybrid propulsion systems (HPS) with emphasis on their electric drive unit.

Following the introduction of the basic topologies of HPS, a case study is focused with an analysis of its current features. Of particular interest, those related to the flux‐weakening range extension and the cost‐effectiveness improvement are rethought in an attempt to stimulate the innovative capabilities of the students.

The adopted methodology has been integrated in a master course and has been found attractive and informative by the students.

The proposed teaching approach should be complemented by appropriate laboratory courses.

Thanks to the proposed methodology, the basis of HPS is no longer restricted to a selected population of the electrical engineering community.

The doubly fed machine (DFM) is presently given an increasing attention in high power variable speed drives and in wind power generation systems, where it exhibits high performances. This has been gained thanks to the stator flux oriented control. Nevertheless, beyond the effect of heating, the robustness of such control strategy is affected by saturation especially the main magnetic one. Accounting for the effect of the magnetizing branch saturation in steady‐state stability analysis, considering the case of a voltage‐controlled DFM and the case of a current‐controlled one, represents the aim of the study. To this end, a numerical procedure based on a combination of the eigenvalue and the fixed point methods has been developed. It has been found that, in both cases, accounting for saturation yields a stabilization effect which is more or less significant depending on the rotor supply parameters.

This paper is devoted to the investigation of the potentialities of induction motor DTC strategies in position control applications.

A comparison study is carried out between two DTC strategies dedicated to position control applications such as robotic: the Takahashi DTC strategy where the induction motor is fed by a two‐level inverter and a new DTC strategy where the induction motor is fed by a three‐level inverter. Special attention is paid to the synthesis of the vector selection table of the second strategy in an attempt to guarantee a high dynamic with reduced ripple of the torque. The comparison study is achieved considering four performance criteria: phase current total harmonic distortion; inverter switching loss factor; quality factor; and inverter commutation frequency.

It has been found that the introduced DTC strategy offers higher performance than the Takahashi one. Of particular interest are: the reduction of both torque ripple and commutation frequency; the eradication of the demagnetization problem which is a vital requirement in position control applications; and the improvement of the power factor thanks to which a reduction of the inverter rating is gained.

This work should be extended considering the validation of the obtained simulation results through experiments.

The paper proposes a new DTC strategy dedicated to position control applications. It allows the elimination of the demagnetization problem from which suffers the Takahashi DTC strategy at low speeds especially at zero speed in position control applications. It also offers a high power factor which opens up crucial cost benefits as far as the inverter rating is concerned.

This paper aims to discuss a comprehensive analysis of the effects of torque and flux hysteresis bands on the inverter average switching frequency considering an induction machine drive under the control of the Takahashi DTC strategy.

The analysis of the effects of torque and flux hysteresis bands on the inverter average switching frequency is carried out taking into account the speed range and the sampling period.

It has been found that the inverter average switching frequency could be more or less taken down according to the speed range and the sampling period by selecting suitable flux and torque hysteresis bands.

This work should be extended by an experimental validation of the established results.

The reduction of the inverter switching frequency is of great importance in direct torque controlled induction motor drive as far as it leads to a decrease of the torque ripple and an increase of the efficiency.

For given torque and flux hysteresis bands, the inverter average switching frequency presents nonlinear shape. Given the fact that the flux switching frequency is a linear function of the speed, one can conclude that the nonlinearity of the inverter average switching frequency is due to the torque switching frequency. This statement has been proven by the introduction of the so‐called focal speeds for the torque switching frequency turns to be null.