Abderrezak Rezzoug

2-D Exact Analytical Model for Surface-Mounted Permanent-Magnet Motors With Semi-Closed Slots

This paper presents an analytical subdomain model to compute the magnetic field distribution in surface-mounted permanent-magnet (PM) motors with semi-closed slots. The proposed model is sufficiently general to be used with any pole and slot combinations including fractional slot machines with distributed or concentrated windings. The model accurately accounts for armature reaction magnetic field and mutual influence between the slots. The analytical method is based on the resolution of two-dimensional Laplaces and Poissons equations in polar coordinates (by the separation of variables technique) for each subdomain, i.e., magnet, air gap, slot-opening, and slots. Magnetic field distributions, back-EMF, and electromagnetic torque (including cogging torque) computed with the proposed analytical method are compared with those issued from finite-element analyses.

On the modeling and design of dual-stator windings to minimize circulating harmonic currents for VSI fed AC machines

The major drawback of usual dual-stator 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. This paper deals with the modeling and design of dual-stator winding ac machines for safe operation with a VSI. A new reference frame model for a dual-stator induction machine (DSIM), including mutual leakage coupling, is proposed. This model allows us to highlight the previously mentioned circulating harmonic currents. The leakage inductance associated with these harmonics is shown to have quite a small value, highly depending on the coil pitch. It is also shown that full pitch is required, and that special slot shape designs should be investigated, to limit the magnitude of circulating currents. Experimental results on a prototype of a DSIM are presented and they show a very good correlation with theoretical curves.

Comparative Study Between Mechanical and Magnetic Planetary Gears

The paper deals with the possibility of replacing a mechanical planetary gear system by a magnetic planetary gearbox. The magnetic planetary gearbox has many advantages such as contact-free, no gear lubrication, high-speed-reduction ratio and high durability. Firstly, the principle of operation, design equations and Willis relation for the magnetic and the mechanical planetary gears are given. A comparative study between the two systems in terms of torque transmission capabilities is presented.

Exact Analytical Method for Magnetic Field Computation in the Air Gap of Cylindrical Electrical Machines Considering Slotting Effects

This paper deals with an analytical method for magnetic field calculation in the air gap of cylindrical electrical machines including slotting effects. The analytical method is based on the resolution of the two-dimensional Laplaces equation in polar coordinates by the separation of variables technique. The originality of the proposed model is to take into account the mutual influence of slots on the air-gap magnetic field. The proposed method is sufficiently general to be used as a tool for air-gap magnetic field calculation of slotted electrical machines as reluctance or permanent magnet motors or actuators. Magnetic field and electromagnetic torque computed with the proposed analytical method are validated through finite-element analysis.

Analytical Computation of the Magnetic Field Distribution in a Magnetic Gear

We propose an analytical computation of the magnetic field distribution in a magnetic gear. The analytical method is based on the resolution of Laplaces and Poissons equations (by the separation of variables technique) for each subdomain, i.e., magnets, air gap, and slots. The global solution is obtained using boundary and continuity conditions. Our analytical model can be used as a tool for design optimization of a magnetic gear. Here, we compare magnetic field distributions and electromagnetic torque computed by the analytical method with those obtained from finite-element analyses.

Comparison Between Finite-Element Analysis and Winding Function Theory for Inductances and Torque Calculation of a Synchronous Reluctance Machine

This paper compares the prediction of two independent methods for calculating electromagnetic torque and inductances of a synchronous reluctance machine under linear condition. One method is based on winding function analysis (WFA) and the other on finite-element analysis (FEA). Both methods take into account the rotor geometry, the stator slot effects and the stator winding connections. The simulation results obtained by the WFA are compared with the ones obtained by two-dimensional FEA. It is shown that the two methods give approximately the same results but require different computation times.

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.

On the design of dual-stator windings for safe VSI fed AC machine drives

The major drawback of usual dual-stator AC machines supplied by a voltage source inverter (VSI) is the occurrence of large circulating harmonic currents, causing extra losses. This paper deals with the design of dual-stator winding AC machines for safe operation with VSI. A new reference frame model of a dual-stator induction machine (DSIM), including mutual leakage coupling, is proposed. The leakage inductance associated with the inaccurate harmonics is shown to have a quite small value, highly depending on the coil pitch. It is also shown that full pitch is required, and that special designs of slot shape should be investigated to limit the negative impact of circulating currents. Experimental results on a prototype of DSIM are presented and they show very good correlation with the theoretical curves.

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

Magnetic saturation effects on the control of a synchronous reluctance machine

Experimental results on the magnetic saturation effects on the control of a small synchronous reluctance machine (600 W) are presented in this paper. A new model of the machine, including saturation effects and cross magnetization, is first developed. An approach based on total and mutual inductances is followed instead of the traditional approach via magnetizing and leakage inductances. All the electrical and mechanical parameters measurement required for the simulations are given. A rotor-oriented vector control of the synchronous reluctance machine is achieved with a DSP board (TMS320C31) and experimental results are presented. When the magnetic circuit is saturated, the simulation with the developed model shows a good accuracy of the results when they are compared to the experimental ones.