Moez Ayadi

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.

Sliding mode control and neuro-fuzzy network observer for induction motor in EVs applications

In order to deal with the major problems of electric vehicle (EV) propelled by an induction motor (IM), a neuro-fuzzy sliding mode control was designed. The proposed scheme uses an adaptive observer that is based on a full order model of the IM in indirect vector-controlled drive. Moreover, it is evaluated on an EV global model taking into account the vehicle dynamics, the thermal effect and the parameters variations. The neuro-fuzzy network is used to adaptively adjust the parameters prediction. However, the sliding mode control can offer many good properties such as good performance against unmodelled dynamics, insensitivity to external disturbance rejection and fast dynamic. Simulations results carried out on a test vehicle, show that the proposed controller is superior to PID one at response speed, steady-state tracking error and resisting perturbation whenever driving or braking. This shows that the proposed scheme is good candidate for EVs propulsion.

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.

Developing a Simplified Analytical Thermal Model of Multi-chip Power Module

Abstract The study of the thermal behavior of power modules has become a necessity regarding the known rapid development in modern power electronics, and the prediction of temperature variation has generally been performed using transient thermal equivalent circuits. In this paper we have developed a simplified analytical thermal model of a power hybrid module. This analytical method is used to evaluate the thermal parameters of a device. The model takes into account the thermal mutual influence between the different module chips based on the analytical method. The thermal interaction between components is dependent on the boundary condition, the dissipated power value in the different components and the number of operating chips constituting the module. This effect is modelled as a source energy and a thermal resistance simply computed tanks to reasonably low measurement applied on the module. The derived thermal models offer an excellent trade-off between accuracy, efficiency and CPU-cost.

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.

Implementation of photovoltaic system into microcontroller

In this paper we have proposed a photovoltaic system connected to the grid (220V/50Hz). The electric system is composed by a DC/DC and DC/AC converters. A maximum-power-point-tracking (MPPT) technique is used to operate in the optimum power condition. This operation is assured by the DC/DC converter. The Dc/Ac converter allows the adaptation of the PV system to the grid. The hysteresis technique is used to generate the output current waveform. All the command algorithms are implemented in a microchip microcontroller.

1D thermal modelling of PMSM intended for an electric vehicle's powertrain

This paper deals with the development of an RC thermal model of a radial permanent magnets synchronous motor dedicated to the traction of an electric vehicle. Temperatures in different levels of the machine are so determined and obtained results are validated through a comparison with respect to ones obtained by finite elements calculation. It has been found that established model gives satisfying values at steady state and has to be reviewed in transient regime.

Electro thermal modeling of the power diode using Pspice

Abstract In this paper, an improved electro thermal model of power diode was developed. The main local physical effects were taken into consideration. The suggested model is able to address the electrical and thermal effects. The model was confirmed through a comparison with other models having close characteristics for different circuits (AC-DC converter, turn-on and turn-off) and different temperatures. The diode was implemented in the Pspice circuit simulation platform using Pspice standard components and analog behavior modeling (ABM) blocks. The diode switching performance was investigated under influence of different circuit elements (such as stray inductance, gate resistance and temperature) in order to study and estimate the on-state and switching losses pre-requisite for the design of various converter and inverter topologies. The comparison shows that these models are simple, tunable with the electric circuit software simulator. They are more capable of predicting the main circuit parameters needed for power electronic design. The transient thermal responses were demonstrated for the single pulse and repeat modes. The achieved results show that our model is suitable for full electro thermal simulations of power electronic circuits.

One-dimensional Lumped-Circuit for Transient Thermal Study of an Induction Electric Motor

Electrical machines lifetime and performances could be improved when along the design process both electromagnetic and thermal behaviors are taken into account. Moreover, real time information about the device thermal state is necessary to an appropriate control with minimized losses. Models based on lumped parameter thermal circuits are: generic, rapid, accurate and qualified as a convenient solution for power systems. The purpose of the present paper is to validate a simulation platform intended for the prediction of the thermal state of an induction motor covering all operation regimes.xa0 To do so, in steady state, the proposed model is validated using finite element calculation and experimental records. Then, in an overload situation, obtained temperatures are compared to finite element’s ones. It has been found that, in both regimes, simulation results are with closed proximity to finite element’s ones and experimental records.

Rectifier Dynamic Electro-Thermal Simulation for Power Factor Correction in Electric Vehicles Application

This paper presents a PFCVF (Power Factor Correction) rectifier that uses a variable frequency source for alternators in electric and hybrid vehicles application. 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 permitting more stability and decreasing the apparent power requirements. A comparative study between the standard and the new technique is made. A thermal network is used to calculate the junction temperatures in order to estimate the equivalent losses in the rectifier with respect of junction temperature modifications and power equilibrium. The relations of the proposed model are defined and simulation results as well as experimental results are discussed.