Noureddine Takorabet

Effect of magnet segmentation on the cogging torque in surface-mounted permanent-magnet motors

We present a method that minimizes the cogging torque in rotor surface mounted permanent-magnet motors. The key idea is to set the distribution of the air-gap flux density by segmenting the magnet pole into several elementary magnet blocks. By choosing either the appropriate elementary magnet block span or the relative position of the magnet blocks, the cogging torque may be significantly reduced. Our analytical approach uses Fourier series to predict the cogging torque harmonics, and finite-element computations. Our numerical results confirm the analytical conclusions.

Design and Analysis of Different Line-Start PM Synchronous Motors for Oil-Pump Applications

This paper presents a comparison between three architectures of line-start PM motors for oil-pump application. This paper is focused on the performances in synchronous operation as well as the self-starting operations. Effects of electrical parameters on the starting and steady performance characteristics are demonstrated to find a satisfying design to meet required performances, it seems that the interior permanent magnet motor yields an impressive starting performance.

Transient Finite Element Analysis of Induction Machines with Stator Winding Turn Fault

In this paper, a time stepping two-dimensional FEM is performed for modeling and analysis of a IM with insulation failure inter-turn fault. FEM analysis is used for magnetic fleld calculation and the magnetic ∞ux density and vector potential of machine is obtained for healthy and faulty cases. Comparing the magnetic ∞ux distribution of healthy and faulty machines helps to detect the in∞uence of turn fault. The machine parameters (self and mutual inductances) are obtained for IM with inter-turn fault. Finally, the FEM machine model is used for studying the machine under difierent fault condition. Study results including phases and fault currents express the behavior of machine with inter-turn faults. The symmetrical current components of IM with difierent fault severity are obtained by FE study and studied. The machine torque in healthy and faulty condition is also obtained and compared. The torque vibration increase upon to degree of fault.

Inductance Identification and Study of PM Motor With Winding Turn Short Circuit Fault

A time stepping FEM is performed for study of PM motor with inter-turn fault. The novel analytical expressions are proposed for calculation of faulty machine inductances from healthy machine parameters. The proposed expressions are validated by FEM and can be used in the circuit based fault models. Finally, the FEM is applied for studying the PM machine under various fault conditions.

Fault Analysis and Parameter Identification of Permanent-Magnet Motors by the Finite-Element Method

We performed a time-stepping finite-element-method (FEM) analysis to study a rotor surface-mounted permanent-magnet synchronous machine with insulation failure inter-turn fault. We used FEM for magnetic field study and determining the machine parameters under various fault conditions. We studied the effect of machine pole number and number of faulted turns on machine parameters. Finally, we used the FEM machine model for studying permanent-magnet machine behavior under different fault conditions.

Experimentally Validated Dynamic Fault Model for PMSM with Stator Winding Inter-Turn Fault

In this paper a simple dynamic model for a PMSM with inter-turn winding fault is derived. FEM is used for parameter determination of the machine with inter-turn fault. This fault model is used to study the behavior of the machine with inter-turn fault. The experimental test is conducted to validate the fault model for different levels of fault severity. The comparison of the results obtained by the model simulation and experimental tests allowed verifying the precision of the proposed dynamic model. This fault model is used to study of the PMSM under various fault conditions and severity and seems to be well adapted for PM motors health monitoring and inter-turn fault diagnosis.

On the Use of Pulse Width Modulation Method for the Elimination of Flux Density Harmonics in the Air-Gap of Surface PM Motors

This paper presents a novel design for the elimination of radial air-gap flux density harmonics of surface mounted permanent magnet (PM) motors by using the pulse width modulation (PWM) method. Instead of conventional full arc-shape magnets, the block magnets are configured to have a shape similar to PWM signals used in power electronics in order to achieve a quasi sinusoidal radial magnetic flux density in the air-gap. Then the obtained electromotive force does not contain the low order harmonics and is almost sinusoidal. The computation of the block magnet sizes is performed by solving a constrained optimization problem. All important variable parameters and constraints are carefully considered in the design process. The solutions are achieved with an optimal design method based on finite element analysis and Matlab optimization toolbox. The effect of different PWM segmented configurations on the flux density waveforms illustrates a high improvement in the quality of the back-EMF as well as the torque.

Study of Different Architectures of Fault-Tolerant Actuator Using a Two-Channel PM Motor

In the context of more electric aircraft, the use of electric actuators instead of hydraulic ones is one of the main topics of research and development in electrical engineering. A high level of reliability, the redundancy, and the compactness are required for aircraft electrical actuators. For achieving these purposes, a classical solution consists in using two identical actuators motorized by one permanent magnet (PM) motor supplied by a voltage source inverter (VSI). In this paper, a solution based on the use of only one fault-tolerant actuator performed by a two-star connected-winding (two-channel) PM motor supplied by two pulsewidth modulated VSIs is proposed. The design of the PM motor can be achieved in two different ways, which are proposed and studied in this paper. The authors focus this paper on the comparison between the two winding architectures and compare the two motors in terms of the short-circuit current and magnetic decoupling of the two windings. Both simulation and experimental results are given and discussed.

Inductance Calculations in Permanent-Magnet Motors Under Fault Conditions

This paper presents a general method based on a permeance network (PN) in order to study stator turn faults in permanent-magnet synchronous machines (PMSMs). This approach includes two main parts: first, static computations are performed to identify the various parameters of a faulty machine. Leakage inductances as well as self and cross saturations are taken into account to improve the results without increasing the CPU time compared to finite element analysis (FEA). Then, a faulty model of the PMSM is used rather than time-stepping finite element method (TSFEM) which requires large CPU time. The model gives dynamical results and it is suitable to studying PMSMs behavior under faults, testing, or investigating fault detection methods under parameter variations. The method can be applied for any type of winding arrangements and different fault configurations. Various comparisons validate the proposed approach to determine precisely the parameters of the PMSM model under turn faults including the saturation effect and leakage inductances.

Estimating Permanent-Magnet Motor Parameters Under Inter-Turn Fault Conditions

This paper presents a theoretical approach as far as faulty permanent magnet synchronous machines (PMSM) are concerned. The knowledge of PMSMs behavior under inter-turn fault is very useful in order to check drive performances under fault conditions. Control, stability and fault detection often require models related to electrical or mechanical faults. The aim of this paper is to develop a dynamic model of a PMSM under fault conditions without using circuit models coupled with finite element analysis (FEA). The method exposed in this paper only needs some preliminary FE computations that can be used in order to include winding distributions and leakage fluxes in the slots.