Lotfi Baghli

A New PWM Strategy Based on a 24-Sector Vector Space Decomposition for a Six-Phase VSI-Fed Dual Stator Induction Motor

This paper presents a new space vector pulsewidth modulation (SVPWM) technique for the control of a six-phase voltage source inverter (VSI)-fed dual stator induction machines (DSIM). A DSIM is an induction machine which has two sets of three-phase stator windings spatially shifted by 30 electrical degrees and fed by two three-phase VSIs. Despite their advantage of power segmentation, these machines are characterized by large zero sequence harmonic currents, and in particular those of order 6 k plusmn 1, which are due to the mutual cancellation between the two stator windings. The proposed SVPWM scheme, while easy to implement digitally, reduces significantly these extra stator harmonic currents. Experimental results, collected from a 15 kW prototype machine controlled by a digital signal processor, are presented and discussed.

Space-vector PWM techniques for dual three-phase AC machine: analysis, performance evaluation, and DSP implementation

The major drawback of dual three-phase ac machines (6phiM), when supplied by a voltage-source inverter (VSI), is the occurrence of extra harmonic currents. These extra currents circulate only in the stator windings and cause additional losses. One solution to reduce their amplitude is to act on the supply side using dedicated pulsewidth modulation (PWM) control strategies. The aim of this paper is to investigate new space-vector PWM (SVPWM) techniques suitable for 6phiM and to perform a detailed analysis and a performance evaluation. The proposed performance criteria, specific to VSI-fed 6phiM, lead to analytical formulas and graphics, which aid the design of high-performance PWM techniques and demonstrate the superiority of the proposed SVPWM techniques. Experimental results carried out on a 15-kW prototype machine and using a low-cost fixed-point TMS320F240 digital signal processor are given and discussed

Space vector PWM techniques for dual three-phase AC machine: analysis, performance evaluation and DSP implementation

The major drawback of usual dual three-phase AC machines (6/spl phi/M), when supplied by a voltage source inverter (VSI), is the occurrence of extra harmonic currents. These extra currents circulate only in the stator windings and cause additional losses. One solution to reduce their amplitude is to act on the supply side using dedicated PWM control strategies. The aim of the present paper is to investigate new space vector PWM (SVPWM) techniques suitable for 6/spl phi/M and to perform a detailed analysis and a performance evaluation. The proposed performance criteria, specific to VSI fed 6/spl phi/M, lead to analytical formulas and graphics, which aid the design of high-performance PWM techniques and demonstrate the superiority of proposed SVPWM techniques. Experimental results carried out on a 15 kW prototype machine and using a low cost fixed point TMS320F240 DSP are given and discussed.

Discontinuous SVPWM Techniques for Double Star Induction Motor Drive Control

In this paper, we present SVPWM control techniques suitable for a double-star induction motor drive (DSIM). The induction machine has two sets of three-phase stator windings spatially shifted by 30 electrical degrees. Each set of three-phase stator windings is fed by a three-phase inverter. Continuous and discontinuous space vector PWM techniques are presented. Implementation on a DSP controller board is achieved and experimental results on a 15 RW DSIM prototype machine are carried out

Torque Ripples Suppression for Six-Phase Induction Motors Under Open Phase Faults

This paper introduces a new disturbance free operation method for six-phase induction motors. The machine is supposed to loss one or more phases and to have a pulsating torque. In order to improve the motor torque, we propose a new control law satisfying a condition required to have a smooth torque. The simulation and experimental results illustrate the validity and the efficiency of the proposed method for disturbance free operation of six-phase induction machines

Decoupling Modeling and Control of Six-Phase Induction Machines Under Open Phase Fault Conditions

Six-phase induction machines are capable of starting and running even with one or more of their stator phases open circuited, but their behavior will be affected. In this paper, in order to study and control these harmful effects, we present a model of six-phase induction machines with up to four phases open. This model illustrates the existence conditions of a pulsating torque under open phase cases. Then, we propose a vector control scheme suppressing the pulsating torque and giving a smooth one. The simulation and experimental results confirm the validity and the efficiency of the proposed method for disturbance free operation of six-phase induction machines

Original article: Modeling of a synchronous reluctance machine accounting for space harmonics in view of torque ripple minimization

The paper deals with modeling of synchronous reluctance motor (SynRM) accounting for all phenomena responsible for torque ripple. Based on winding function approach, the proposed model consists in computing self and mutual inductances considering no sinusoidal distribution of stator windings, slotting effect and no sinusoidal reluctance variation caused by the rotor saliency. Then, optimal current waveforms are determined for each rotor position by solving a second order equation to reduce torque ripple. These currents are used within a vector control scheme. Satisfactory agreement between simulation and experimental results is obtained.

Independent and Direct Rotor-Flux Oriented Control of series-connected induction machines using decoupled Kalman-filters

This work deals with an Independent and Direct Rotor-Flux Oriented Control (IDRFOC) of series-connected two-induction machines. This consists of connecting a six-phase motor with a three-phase one. The independence of flux-observers of both machine is predicted analytically from state equation. The Kalman observer is chosen to perform the estimation of the flux of each machine. Simulation results demonstrate the independence of flux observers and controls of both machines.

Study and Simulation of Direct Torque Control of Double-Star Induction Motor Drive

The major drawback of usual dual three-phase AC machines when supplied by a voltage source inverter (VSI), is the occurrence of extra harmonic currents. These extra currents circulate only in the stator windings and cause additional losses. One solution to reduce their amplitude is to act on the supply side using dedicated PWM control strategies. In this paper, we present a Direct Torque Control technique of a double-star induction motor drive (DSIM). The induction machine has two sets of three-phase stator windings spatially phase shifted by 30 electrical degrees. Each set of three-phase stator windings is excited by a three-phase inverter. Simulation results have been presented to show the effectiveness of the dual-three phase DTC scheme for double star induction motor.

A stator flux oriented drive for an induction motor with extra (/spl alpha/, /spl beta/) coils

This paper deals with an implementation of a stator flux oriented method on a DSP board to drive an induction motor. This method is based on the integration of EMF directly provided by two extra coils located on the equivalent /spl alpha/, /spl beta/ reference axes of the stator. The open-loop integration problem is solved thanks to an online offset compensation algorithm which offers robustness especially at low speed. Experimental results of speed control are presented and commented to show the effectiveness of this method.