Rafik Neji

PMSM cogging torque reduction: Comparison between different shapes of magnet

In most of the industrial applications, such as vehicular traction, when a Permanent Magnet Synchronous Motor (PMSM) can be used, a low cogging torque is required. The air gap variation, the magnet shapes and stator slots forms are the origins of cogging torque. In this work which aims at reducing cogging torque, we focus on the rotor magnet shapes optimizations. From intensive Finite Elements (FE) simulations of a Surface-mounted Permanent Magnet Synchronous Motor (SPMSM), 3-phases, 2-pairs of pole and 36 stator slots (3-circuits by pole and phase), a cogging torque reduction can be reached. The effect of different magnet shapes on cogging torque is studied in order to identify the optimal design for each one.

Experimental Investigations for Thermal Mutual Evaluation in Multi-Chip Modules

The thermal behavior of power modules is an important criterion for the design of cooling systems and optimum thermal structure of these modules. An important consideration for high power and high frequency design is the spacing between semiconductor devices, substrate structure and influence of the boundary condition in the case. This study focuses on the thermal behavior of hybrid power modules to establish a simplified method that allows temperature estimation in different module components without decapsulation. This study resulted in a correction of the junction temperature values estimated from the transient thermal impedance of each component operating alone. The corrections depend on mutual thermal coupling between different chips of the hybrid structure. A new experimental technique for thermal mutual evaluation is presented. Notably, the classic analysis of thermal phenomena in these structures, which was independent of dissipated power magnitude and boundary conditions in the case, is incorrect.

Induction machine DTC optimization using artificial intelligence for EV's applications

A three-phase squirrel-cage induction motor is used as a propulsion system of an electric vehicle (EV). The motor is controlled at different operating conditions using a direct torque control (DTC) technique known to have simple control structure with comparable performance. Whereas in a conventional DTC drive, the weakest points is the optimal voltage space vector choice. In this paper Artificial Intelligence is used to achieve an optimal selection of voltage space vectors. The European drive cycle ECE-15 is used for validation. The simulation results show that the proposed DTC optimization using artificial intelligence scheme for induction motors is a good candidate for EVs propulsion.

Application of Evolutionary Algorithm for Triobjective Optimization: Electric Vehicle

For Electric Vehicles (EVs), Weight and losses reduction are important factors not only in reducing the energy consumption and cost but also in increasing autonomy. This paper describes the application of an evolutionary algorithm for multiobjective optimization in the traction chain (TC) of pure EV. In this study, the optimisation algorithm is based on the Strength Pareto Evolutionary Algorithm (SPEA-II) and the fitness function is defined so as to minimize the electric vehicle cost (EVC), the electric vehicle weight (EVW) and the losses in the electric vehicle (EVL). Also, in this study, different requirements are considered as constraints like the efficiency of the permanent magnets engine, the number of conductor in the slots, the winding temperature…The simulation results show the effectiveness of the approach and reduction in EVC, EVW and EVL while ensuring that the electric vehicle performance is not sacrificed.

Power Factor Correction Rectifier with a Variable Frequency Voltage Source in Vehicular Application

This paper presents a PFCVF (Power Factor Correction) rectifier that uses a variable frequency source for alternators for electric and hybrid vehicles application. In such application, the frequency of the signal in the alternator changes according to the vehicle speed, more over the loading effect on the alternator introduces harmonic currents and increases the alternator apparent power requirements. To overcome these problems and aiming more stability and better design of the alternator, a new third harmonic injection technique is proposed. This technique allows to preserve a good THD (Total Harmonic Distortion) of the input source at any frequency and to decrease losses in semiconductors switches, thereby allowing more stability and reducing the apparent power requirements. A comparative study between the standard and the new technique is made and highlights the effectiveness of the new design. A detailed analysis of the proposed topology is presented and simulations as well as experimental results are shown.

Performance comparison on three parameter determination method of fractional PID controllers

The objective of this work is to define the fractional order PID and the approximation of the integral and derivation of fractional order to render the system from irrational to rational. The parameters of PID are determined by three methods. These fractional controllers have two parameters more than the conventional PID controller, two more specifications can be met, improving the performance of the system, the fractional orders, α and β are determined by minimized the ISE. For the tuning of the controller an iterative optimization method has been used, based on a nonlinear function minimization. Illustrative example is presented and simulation results show the effectiveness of this kind of controllers.

Thermal behavior of a three phase inverter for EV (Electric Vehicle)

Power modules including IGBT are widely used in the applications of motor drivers in Electric Vehicle. The thermal behavior of these modules becomes more important to choose the optimum design of cooling system. In this paper, we propose a RC thermal model of the dynamic electro-thermal behavior of IGBT PWM (Pulse Width Modulation) inverter modules. This model is used to estimate the maximum junction temperature of the module. The thermal behaviors of the junction and power dissipation are studied with and without influences between the module components. The electro-thermal model is implemented and simulated with MATLAB simulator.

Electrothermal modeling of hybrid power modules

Purpose – Power modules including the insulated gate bipolar transistor (IGBT) are widely used in the applications of motor drivers. The thermal behavior of these modules makes it important to choose the optimum design of cooling system. The purpose of this paper is to propose an RC thermal model of the dynamic electro‐thermal behavior of IGBT pulse width modulation inverter modules.Design/methodology/approach – The electrothermal model has been implemented and simulated with a MATLAB simulator and takes into account the thermal influence between the different module chips based on the technique of superposition.Findings – This study has led to a correction of the junction temperature values estimated from the transient thermal impedance of each component operating alone.Originality/value – In this paper, an experimental technique of a thermal influence evaluation is presented.

Performance comparison of PI, SMC and PI-Sliding Mode Controller for EV

This paper presents three different control strategies for controlling an induction motor “IM” in an electric vehicle (EV) application. The control techniques analyzed and compared are: the proportion-integral regulator (PI), the sliding mode control (SMC) and the PI-Sliding Mode Control (PI-SMC). Simulation results show the comparison performance in term of robustness.

Fuzzy control for speed tracking of an electrical vehicle enclosing an axial-flux synchronous motor

The present work deals with the design of a fuzzy controller insuring speed tracking of a leisure electrical vehicle. Traction motor is an axial-flux permanent-magnet one arranged in a TORUS configuration. Firstly, all parts of the vehicle powertrain are described then analytically modelled. Further, controller membership functions are introduced and fuzzification/defuzzification rules are defined. Finally, established model is tested considering two kinds of speed instructions. It was found that studied motor satisfy speed tracking requests according to vehicle specificities.