Yacine Azzouz

DC/DC and DC/AC Converters Control for Hybrid Electric Vehicles Energy Management-Ultracapacitors and Fuel Cell

This paper presents the ultracapacitors and the fuel cell (FC) connection for hybrid electric vehicles (HEVs) applications. An original method for the embedded energy management is proposed. This method is used to share the energetic request of the HEV between the ultracapacitors and the FC. The ultracapacitors are linked to dc-bus through the buck-boost converter, and the FC is connected to dc-bus via a boost converter. An asynchronous machine is used like traction motor or generator, and it is connected to dc-bus through an inverter. A dc-motor is used to drive the asynchronous machine during the decelerations and the braking operations. The main contribution of this paper is focused on the embedded energy management based on the new European drive cycle (NEDC), using polynomial control technique. The performances of the proposed control method are evaluated through some simulations and the experimental tests dedicated to HEVs applications.

New Behavioral Modeling for DC Motor Armatures Applied to Automotive EMC Characterization

This paper presents a high-frequency modeling method of direct current motor armatures dedicated to low-voltage automotive applications. The proposed model is based on a behavioral approach, which permits to reproduce impedance measurements. It takes into account some physical features and phenomena related to the motor armature. The influence of the skin effect in the windings, the magnetic field penetration in the core, and the armature manufacturing systematic error in the impedance evolution is considered with this model. The model was first developed from that of a basic iron core inductor and improved afterward in order to cover a high frequency range (from dc up to 1 GHz). Several identification methods were used to quantify the model parameters. Furthermore, the model was associated to a noise-current generator in order to estimate the conducted disturbances. These last ones are emitted by the motor in the RF range (100 kHz-108 MHz), knowing the operating conditions of current intensity, voltage, and speed.

New Behavioral Modeling of EMI for DC Motors Applied to EMC Characterization

This paper is dealing with the characterization of the electromagnetic compatibility of the direct current (dc) motors. It acts as the complements of the works achieved recently for the modeling of dc motor impedances. The contact mechanisms between the brushes and the collector blades which cause the electromagnetic interferences (EMIs) are explained and modeled. Knowing the operating conditions of the current intensity, voltage, and speed, EMIs are measured and analyzed in radio frequencies from 100 kHz to 108 MHz. The behavioral model proposed is based on Nortons equivalent circuit where the motor is assumed as a current generator representing the EMI source, associated in parallel with its impedance model. Specific identification methods are used to quantify the EMI model parameters. It is shown that the model is in good correlation with the measurement. The model was applied for estimating the conducted EMI generated by a dc motor with its filters, and then, validations with different dc motors were performed.

Experimental Investigation on the Power Electronic Transistor Parameters Influence to the Near-Field Radiation for the EMC Applications

With the increases of the module integration density and complexity in electrical and power electronic systems, serious problems related to electromagnetic interference (EMI) and electromagnetic compatibility (EMC) can occur. For the safety, these disturbing efiects must be considered during the electronic equipment design process. One of the concerns on EMC problems is induced by unintentional near-fleld (NF) radiations. The modeling and measurement of EM NF radiations is one of the bottlenecks which must be overcome by electronic engineers. To predict the unwanted difierent misbehaviors caused by the EM radiation, NF test benches for the reconstitution of scanning maps at some millimeters of electrical/electronic circuits under test were developed at the IRSEEM laboratory. Due to the di-culty of the design with commercial simulators, the prediction of EM NF emitted by active electronic systems which are usually based on the use of transistors necessitates more relevant and reliable analysis techniques. For this reason, the main focus of this article is on the experimental analysis of EM NF radiated by an MOSFET transistor with changing electrical parameters. Descriptions of the experimental test bench for the EM map scan of transistors radiation are provided. This experimental setup allows not only to detect the EM NF emission but also to analyze the in∞uence of the excitation signal parameters

A new active common-mode voltage elimination method for three-Level Neutral-Point Clamped inverters

Common-mode voltage (Vcm) generated by voltage inverters is observed on motor windings. This voltage may induce bearing currents, which can eventually damage AC motors and cause larger common-mode currents. Many methods are proposed to eliminate or reduce the common-mode voltage. Most of these methods reduce the DC-bus voltage utilization and increase the output voltage harmonics. This paper introduces a new Active Common-Mode Elimination (ACME) modulation for three-Level Neutral Point Clamped (3L-NPC) inverters. This method is based on a Modified Space Vector Modulation (MSVM) method and a power circuit system located between the inverter and the induction motor. MSVM eliminates the redundant switching states that produce high Vcm levels. Then, the power circuit system eliminates entirely the Vcm. Simulation results show the effectiveness of the proposed method. This method can increase the utilization rate of the DC bus voltage and to reduce voltage harmonics.

A new dead-time effect elimination method for H-bridge inverters

Dead-time is added into traditional pulse width modulation (PWM) control to avoid short circuit of DC link of inverters. The dead-time can cause problems such as voltage loss, increasing the value of total harmonic distortion of the current waveform (THDI) as well as output current distortion at the zero-crossing. To solve these problems, many studies have been made to deal with the dead-time issues. This paper presents a novel dead-time effect elimination method for H-bridge inverters based on three-level PWM strategy. In this paper, a new current polarity detection circuit has been used to remove dead-time between signals. This detection circuit is based on the conduction states of two low antiparallel diodes in IGBT modules. Here, only one power supply is needed for the diode states conduction detection. In this paper, the principle of the proposed method is detailed. Moreover, simulation and experimental results are presented to demonstrate the validity of the proposed method.

Embedded energy management based on DC/DC converters - Ultracapacitors and Fuel Cell

This paper presents the Ultracapacitors (UC) and Fuel Cell coupling with an original energy management method for Hybrid Electric Vehicles (HEVs) applications. Ultracapacitors are coupled to the DC-link through Buck-Boost converters. The Fuel Cell is connected to the DC-link using boost converter. An asynchronous machine is used like traction motor; it is coupled to DC-link using an inverter. The main contribution of this paper is focused on Hybrid Sources (Ultracapacitors and Fuel Cell) currents, DC-link voltage control, and Asynchronous machine Speed control based on polynomial controllers called RST correctors. Through some simulations and experimental results, the authors present an improved energy management for Hybrid Electric Vehicles applications.

Optimal power coefficient for load balancing and reactive power compensation In DFIG-WTS

Doubly-Fed Induction Generators (DFIG) are widely used nowadays in grid-connected Wind Turbine Systems (WTS). The typical control strategy for WTS is the maximum power coefficient tracking method. However, this method limits desirable ancillary services from WTS, such as power quality improvement in the network. Therefore this paper derives the optimal reference power coefficient of the WTS that can enhance the participation of the DFIG in the load balancing and reactive power support to the grid. The unbalanced power compensation is performed only by the Grid Side Converter (GSC), while a proper reactive power share between the GSC and the rotor side converter is used to achieve optimal active power injection. The performance of the proposed optimization approach, based on the capability curve of the DFIG-GSC in steady state, is compared with the typical maximum power point tracking method. The results were obtained by simulating a 2-MW DFIG-WTS in MATLAB/Simulink.

Predictive current control for neutral-point voltage regulation and load balancing in three-level grid connected compensator

In recent years many studies have treated the neutral-point voltage regulation problem in the Neutral-Point-Clamped (NPC) converter. Besides, many works have proposed appropriate control strategies for these grid interfacing NPC converters to compensate the problem of load current unbalance and power factor correction. This paper addresses both problems. Therefore, a predictive current control method for a three-level NPC converter capable of simultaneously compensating the problems of: neutral-point voltage regulation, load balancing and power factor correction is presented. The discrete-time model of the system is used to predict the future value of the converter currents and the capacitors voltages for all possible voltage vectors. The voltage vector which minimizes a given cost function is chosen. Reference converter currents are generated using the instantaneous p-q theory. The simulation results of the proposed method are analyzed, and its good performance is verified compared with the traditional carrier-based PWM strategy using zero-sequence voltage injection.

Analogue Behavioral Modeling of GTO

An analog behavioral model of high power gate turn-off thyristor (GTO) is developed in this paper. The fundamental methodology for the modeling of this power electronic circuit is based on the use of the realistic diode consideration of non-linear junctions. This modeling technique enables to perform different simulations taking into account the turn-on and turn-off transient behaviors in real-time. The equivalent circuits were simulated with analog software developed in our laboratory. It was shown that the tested simple and compact model allows the generation of accurate physical characteristics of power thyristors under dynamic conditions. The model understudy was validated with analog simulations based on operational amplifier devices.