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An ultrahigh step-down converter with a low number of semiconductor devices is presented in this article. Important features of this converter are simple structure with low size and cost, low voltage and current stress on components, low output current ripple, and low conduction and switching losses. In this converter, the power switches are turned on under zero current switching (ZCS) condition, whereas the output diodes commutate under ZCS condition without any auxiliary circuit. Thereby, in addition to the converter efficiency improvement, the diodes reverse recovery problem is alleviated. The proposed topology has employed a two-phase interleaved structure to reduce current stress, three windings coupled inductors to further decrease the voltage gain, and two series capacitors to diminish the voltage stress on the semiconductors elements and recover the leakage inductances energy. The experimental results of an implemented prototype are provided to evaluate the effectiveness of the proposed topology at 100 kHz and 200 W, which converts a 400-V input voltage into a 12-V output voltage.

In this paper, an effective control strategy is proposed to manage energy distribution from fuel cells and batteries for hybrid electric boat applications. The main objectives of this real-time control are to obtain fast current tracking for the batteries’ system, the DC bus voltage stability by using a fuel cell, and energy load distribution for a hybrid electric boat under varying demand conditions. The proposed control strategy is based on a combination of frequency approach and current/voltage control of interleaved boost converters to reduce the hydrogen consumption by the fuel cell and improve the quality of energy transfer. The frequency approach was dedicated to managing the DC power-sharing between the load, the fuel cell, and the batteries’ storage system by extracting the power references. The closed loop control system utilized to control the energy is based on the DC/DC converters. The performance evaluation of the proposed control strategy has been tested through a real-time experimental test bench based on a dSPACE board (DS1104).

International audience; This paper presents the aging characterization and modeling of lithium iron phosphate (LiFePO4) batteries. The research work suggested here aims to characterize the aging of the resistances and the capacities of the batteries as a function of using temperature and direct current undulations. The proposed model of the LiFePO4-batteries is for multi-source systems such as distributed power generation systems based renewable energies. The performances of the batteries used in these systems can be affected by the temperature and the DC-current undulations. The characterization system takes into account the temperature and the DC-current undulations as thermal and electric constraints for batteries. The experimental tests are performed through charging and discharging operations using calibrated fluctuating DC-current waveforms. The experimental measurements and simulations results found are similar with a deviation less than 1%. Hence the proposed model is very appropriate to predict the degradation of battery parameters caused by combined impacts of direct current undulations and the temperature.

International audience; A freight transport hybrid electric boat (HEB) is investigated in order to improve the dynamic response of the boat during the rapid variations of the onboard load such as the acceleration/deceleration, the braking, the docking maneuvers operations, and the goods package lifting system. The propulsion architecture is based on a variable-speed diesel generator (DG) used as the main energy source, with the multiple energy storage system based on the supercapacitors (SC) and the batteries which are used in the HEB to answer the intermittent power due to a sudden load change. This solution compensates the fluctuations from the load by reducing their impacts for diesel engine. The variable-speed diesel generator is connected to the dc-bus using three-phase controlled rectifier to manage dc-bus voltage. The SC and the batteries are linked to dc-bus through two bidirectional dc/dc converters to control the high-frequency component independently to those of the average-frequency component. Two identical thrusters are, respectively, placed in the front of and the behind of the boat to emulate the propulsion operations. The HEB power demand includes the thruster's requirements and embedded appliances (elevator, package lifting system, heating system, TV, computer, and electronics device for navigation). The main contribution of this paper is focused on the HEB dynamic response improvement during the rapid variations of the load using the SC and the batteries. Other significant contributions are based on the LiFePO4-battery modeling using solartron analytical impedance spectroscopy and the load current sharing between the DG and the SC/batteries, where the high-frequency component of the load is assigned to SC due to its fast dynamic response and that of the average frequency is allocated to the batteries. The proposed energy management strategy is verified by the simulation and experimental tests in reduced scale using a specific driving cycle of the HEB for one trip.

This paper presents a new approach for supercapacitors characterization using impedance spectroscopy taking into account the dynamics constraints, such as temperature, current ripple rate and cycling frequency. This characterization is done using Modulab XM test bench. The main goal of this study is to show the parameters evolution which can serve to find out the supercapacitor energetic performances. From experimental data, the parameters of the supercapacitor (series resistance and capacitance) are calculated from the Nyquist diagrams. The contribution of this paper is focused on the parameters dependence study according to the dynamics constraints listed previously (temperature, current ripple rate and the cycling frequency) and their combination (temperature-current ripple rate and current ripple rate-cycling frequency). Finally, the experimental results, which show a dependence of series resistance (ESR) and capacitance (C) compared to these constraints, are presented.

International audience; This paper presents a new approach for supercapacitors (SCs) characterization using temporal method taking into account the influence of the dynamics constraints, such as number of cycles and rms value of DC-current ripple. This characterization is done using supercapacitor cycler BT2000 test bench. From experimental data, the parameters of the supercapacitor (SC) (series resistance and capacitance) are calculated from the voltage response compared to current input. The contribution of this paper is focused on the parameters dependence study according to the dynamics constraints listed previously (number of cycles and rms value of DC-current ripple). Finally, the experimental results, which show a dependence of series resistance (ESR) and capacitance (C) compared to these constraints, are presented.; Cet article présente une nouvelle approche pour la caractérisation des supercondensateurs (SC) utilisant la méthode temporelle prenant en compte l'influence des contraintes dynamiques, telles que le nombre de cycles et la valeur efficace de l'ondulation du courant continu. Cette caractérisation est effectuée à l'aide du banc d'essai du cycleur à supercondensateur BT2000. À partir de données expérimentales, les paramètres du supercondensateur (SC) (résistance série et capacité) sont calculés à partir de la réponse en tension par rapport à l'entrée de courant. La contribution de cet article est centrée sur l'étude de la dépendance des paramètres en fonction des contraintes dynamiques listées précédemment (nombre de cycles et valeur efficace de l'ondulation du courant continu). Enfin, les résultats expérimentaux, qui montrent une dépendance de la résistance série (ESR) et de la capacité (C) par rapport à ces contraintes, sont présentés.

International audience; This article deals with the three level space vector pulse width modulation (SVPWM) technique to control the Neutral Point Clamped (NPC) inverter for energy management in a multi-source system based on a variable speed diesel generator, a PV generator, and a pack of the lithium-batteries for the micro grid applications. The contribution of the paper is focused on the multi-source system energy management using the frequency components distribution method between the linked sources according to the dynamic response capability of the each source.; Cet article traite de la technique de modulation de largeur d'impulsion vectorielle spatiale à trois niveaux (SVPWM) pour contrôler l'onduleur Neutral Point Clamped (NPC) pour la gestion de l'énergie dans un système multi-source basé sur un générateur diesel à vitesse variable, un générateur PV et un pack des batteries au lithium pour les applications micro-réseau. La contribution de l'article se concentre sur la gestion de l'énergie du système multi-sources en utilisant la méthode de distribution des composantes de fréquence entre les sources liées en fonction de la capacité de réponse dynamique de chaque source.

International audience; This paper presents the supercapacitors (SC) behavior characterization using the temperature combined to the frequency of the dc-current ripples called here electro-thermal stress. To characterize the evolution of the resistance and the capacitance of the SC, the authors have evaluated the impact of the state of charge (SoC), the number of cycles, the temperature, and the temperature combined to the frequency of the dc-current ripples. This approach enables to show the variations of the SCs resistance and capacitance according to the real constraints imposed by application. The main contribution of this paper is focused on the SCs aging characterization and modeling, using the electro-thermal stress. The experimental tests of the SC characterization and modeling are based on the charge/discharge operations, using the fluctuating and no-fluctuating dc-current waveforms. The proposed model takes into account the variations of the resistance and capacitance of the SC according to the temperature, the frequency of dc-current ripples and the SoC. The terminal voltage of the SC obtained from the proposed model is close to the experimental result, with an error about 1%. So, the proposed model is satisfactory to predict the SCs behavior during the charge/discharge operations using a fluctuating dc-current combined to a variable temperature and SoC.

In this paper, a hybrid electric power supply system for an electric vehicle (EV) is investigated. The study aims to reduce electric stress on the main energy source (fuel cell) and boost energetic performances using energy sources with high specific power (supercapacitors, batteries) for rapid traction chain solicitations such as accelerations, decelerations, and braking operations. The multisource EV power supply system contains a fuel cell stack, a lithium batteries module, and a supercapacitors (Sc) pack. In order to emulate the EV energy demand (wheels, weight, external forces, etc.), a bidirectional load based on a reversible current DC-DC converter was used. Fuel cell (Fc) stack was interfaced by an interleaved boost converter. Batteries and the Sc pack were coupled to the DC point of coupling via buck/boost converters. Paper contribution was firstly concentrated on the distribution of energy and power between onboard energy sources in consonance with their dynamic characteristics (time response). Second contribution was based on a new Sc model, which takes into consideration the temperature and the DC current ripples frequency until 1000 Hz. Energy management strategy (EMS) was evaluated by simulations and reduced scale experimental tests. The used driving cycle was the US Federal Test Procedure known as FTP-75.

International audience; This paper highlights the three level space vector pulse width modulation (SVPWM) technique to control the Neutral Point Clamped (NPC) inverter for energy management in a multi-source system based on a diesel generator, a wind turbine, a PV generator, and a pack of the lithium-batteries for micro grid applications. The contribution of the paper is focused on the multi-source system energy management using the frequency components distribution method between the linked sources according to the dynamic response capability of the each source.; Cet article met en évidence la technique de modulation de largeur d'impulsion vectorielle spatiale à trois niveaux (SVPWM) pour contrôler l'onduleur Neutral Point Clamped (NPC) pour la gestion de l'énergie dans un système multi-source basé sur un générateur diesel, une éolienne, un générateur PV et un pack de batteries au lithium pour applications micro-réseau. La contribution de l'article se concentre sur la gestion de l'énergie du système multi-sources en utilisant la méthode de distribution des composantes de fréquence entre les sources liées en fonction de la capacité de réponse dynamique de chaque source.

International audience; In this paper a combination of isolated DC-DC resonant converters is proposed to interface an electrical hybrid system composed of a battery bank as the main energy source and a bank of supercapacitors (SC) as the auxiliary power source. The battery bank is connected to a DC-bus via an isolated LLC resonant converter, while the SC bank is coupled to the DC-bus through a symmetrical bidirectional CLLC resonant converter. This allows soft switching and enables high switching frequency operations, and then guarantee high power density and high efficiency. An energy management strategy for the proposed structure is studied and implemented. The proposed approach relies on the energetic behavior of the sources to share the required power. The simulation results prove the efficiency of the proposed energy management strategy as well as the performance of the resonant converters.

International audience; This paper deals with an energy management improvement based on frequency sharing approach for an electric vehicle. In order to satisfy the traction/propulsion system requirement, the Fuel cell (FC) system is assisted by lithium-ion batteries and Supercapacitors (SC). Bidirectional Buck Boost converters link the batteries and Supercapacitors to the DC-Bus. The FC stack is connected to the DC-Bus by an interleaved Boost DC-DC converter. The traction/propulsion motor is a permanent magnet synchronous motor (PMSM) coupled to a DC motor in order to emulate the vehicle's load and energy requirements during the driven cycle. The DC-Bus feeds the permanent magnet synchronous motor via a bidirectional DC-AC converter. The contribution of this study involves EV's energy effort sharing between Supercapacitors, Fuel cells and Lithium-ion batteries, taking into account the dynamic responses and electrical performances of each energy sources. The effectiveness of the control is verified through simulations performed on Matlab/Simulink software.

International audience; In this paper, an electrical energy management strategy to control the power flow in a battery/supercapacitor hybrid system is presented. The implemented approach relies on the dynamics response of the sources to share the required power. The concept of the system relies on isolated resonant converters. A primary phase-shifted LLC resonant converter is used to connect the batteries bank to the DC-link, while the supercapacitors bank is coupled to the DC-link through a bidirectional CLLC resonant converter controlled by variable frequency control. Performances of the proposed architecture and control method are validated through some simulations. It is shown that the proposed converters can achieve soft switching for all load conditions. That the efficacy and the power density of the system are enhanced. The simulation results validates also the proposed energy management strategy.

This paper presents utilization of the Energetic Macroscopic Representation (EMR) which is a graphical formalism tool to analyze the behavior of a wind energy conversion (WEC) system based on a permanent magnet synchronous generator (PMSG). The aims of this paper are showing the clarity of this tool in the representation of complicated energy systems and the effectiveness of the control strategy deduced from this representation. More precisely, this paper starts from a synoptic with a simple knowledge of a wind energy conversion system to deduce a diagram for the control law based on the action and reaction principle. The methodology of this tool is described in details and the simulation results obtained in MATLAB environment are presented.

This paper discusses two control strategies for a small-scale wind energy conversion system developed for micro-grids applications. Whereas control of small-scale Doubly Fed Induction Generator (DFIG)-based wind turbines is not easy to achieve we have developed control strategies for the rotor-side converter, as well as mathematical modeling of the configuration that has been employed. Fixed speed control (direct speed control) and variable speed control (indirect speed control) of the generator rotor are developed, in which a simple maximum power point tracking method was used without taking into account the turbine blade angle. The control approaches are then simulated in MATLAB/Simulink, and the developed models are then used to highlight the behavior of the system. The simulation results are presented and discussed in order to compare the two control strategies especially developed for small-scale wind turbines.

In order to get correct results using the Model Predictive Control (MPC), one must find the suitable values of its parameters. Despite a large number of papers in literature on MPC tuning methods, there is no available analytical approach permitting to identify explicitly the robustness area of a process independently of its order. Here we intend to overcome this limit thanks to an analytical one. The interest of our approach is to be applicable to a wide set of linear controllable and observable single-input single-output (SISO) processes. The issues of optimal closed-loop stability and the energy consumed are addressed in this paper. The proposed method is tested experimentally via a DC motor. Finally, a performance comparison is made with existing methods to emphasize its effectiveness.

DC-DC resonant converters are increasingly used in renewable energy systems and hybrid electric vehicles because of their high power density and high efficiency. This paper establishes a global study of the most popular topologies of DC-DC resonant converters that is series, parallel, series-parallel, LLC and CLLC resonant converters. First harmonic approximation method (FHA) is used to define the equivalent circuit and to analyse the gain characteristics and limitations of each topology.

International audience; In this paper, an improved bidirectional resonant converter for wide battery voltage applications is proposed. The topology has a symmetrical resonant circuit which guarantees an identical behaviour for both energy transfer directions. The proposed converter has the capability to achieve soft switching for both bridges and the ability to operate under wide input/output voltage with narrow switching frequency variation. That increases the efficiency for both energy transfer directions. First harmonic approximation method (FHA) is used to define the equivalent circuit and to analyse the gain characteristics of the converter. Performances of the proposed converter for wide battery voltage application are evaluated through some simulations using Matlab/Simulink software.

International audience; This paper describes an energy management strategy for an electric vehicle (EV). The proposed EV architecture contains a pack of the batteries which presents the energy source and a pack of the supercapacitors (SC) used as power source. The pack of the batteries produces the necessary energy to move forward the vehicle while the pack of the SC produces the lacking power in acceleration and in braking phases. Two DC-DC converters are used to interface the energy sources with the DC-bus. A bidirectional DC-AC converter is used to connect the traction motor to the DC-bus. The proposed control method is focused on the power flow management within the EV depending on electrical behavior of the energy sources. The validity of the proposed control strategy is proofed through some reduced scale simulations tests using the New European Driving Cycle (NEDC).

International audience; In this paper, the control and energy management strategy are proposed for an electric vehicle (EV) application. The hybrid source is composed of Fuel Cell (FC) and Ultracapacitors (UCs). The proposed energy management is used to share the EV energy requirement between the hybrid energy source, where the UCs are connected to DC-bus through a bidirectional DC/DC converter, and the FC is linked to the DC-bus through unidirectional DC/DC converter. The main purpose of this paper is focused on EV requested power sharing in real time operations between the FC stack and the UCs according to the electrical characteristics of these sources using polynomial correctors. In this study, only the traction operation mode is considered. The validity of the control is proofed through reduced scale experimental tests.

International audience; This paper presents coordinated power management strategies for a hybrid electric boat (HEB) based on dynamic load's power distribution approach using diesel generators and batteries. Two variable-speed diesel generator sets connecting to dc-bus via fully controlled rectifiers serve as the main power supply source; one lithium-battery pack linked to dc-bus through a bidirectional DC/DC converter serves as an auxiliary power supply source. The power requirement of the thrusters and other onboard equipment is represented by a load power profile. The main contribution of this paper is focused on the load power sharing of the HEB between the two variable-speed diesel generators and the lithium-battery pack, through the fluctuations extracted from load power and their assignation to the batteries. Another important issue is that when the total load demand is low, one of the diesel generator set will be switched off to improve the diesel-fuel efficiency. The output powers of the diesel generators and the batteries are controlled based on the power distribution strategy via the converters controlling. The performances of the proposed hybrid power system control are evaluated through simulations in MATALB/Simulink, and through reduced-scale experimental tests carried out for a specific driving cycle of the HEB.

International audience; This paper presents energy management strategy for electric vehicle (EV) applications. The proposed method is used to share the requested energy of the EV between the ultracapacitors (UCs) and lithium-batteries. The traction motor is a Permanent Magnet Synchronous Machine (PMSM) controlled by a Voltage-Source-Inverter (VSI) and fed by the UCs and the batteries. The energy storage system (ESS) is connected to DC-bus through two DC-DC converters. The aim of this paper is focused on requested EV power sharing between UCs pack and the batteries pack according to the dynamic response of these sources using anti-windup PI controller. This study is based on a real example of EV, in addition only the traction mode is considered. The performances of the proposed method are evaluated through some simulations using MATALB/Simulink software.

This paper proposes an effective control strategy to enhance the Low Voltage Ride-Through (LVRT) capability of an offshore wind turbine connected to the grid. A new nonlinear control method based on differential flatness property of systems is applied to control the wind turbines in where, the system control is carried out by planning the appropriate trajectories on components of the output variables vector of the system. Also, the reactive power of variable speed wind turbine is managed in this work in order to respect the grid code requirements during voltage dips as well as to reduce their impacts on the grid. Simulation of the system model is carried out in Matlab/SimPowerSystems. The simulation results are presented to demonstrate the effectiveness and robustness of the Flatness-Based Control (FBC) to enhance LVRT of the offshore wind turbine.

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.

International audience; This paper presents a frequency-based approach energy management in an Electrical Hybrid Boat (EHB) application. An association of a variable speed Diesel Permanent Magnet Generator (Diesel-PMG) with a supercapacitor and a battery bank is proposed to satisfy energetic demand of EHB. The supercapacitor and the battery bank are connected to DC-link via bidirectional DC/DC converters, while the variable speed Diesel Generator is connected to DC-link through a three phase controlled rectifier. The two DC/AC converters connected to two electric motors are used as thrusters system which emulates energetic demand of Electrical Hybrid Boat in propulsion operations. Power requirements of the thrusters are then emulated in a programmable electrical load to simulate the load profile. The contribution of this paper is focused on load's profile sharing between a variable speed Diesel Generator, a supercapacitor and a battery bank according to dynamic responses of each source. The performances of proposed method are evaluated through experimental results obtained by a dSPACE-based test bench.

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.

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.

International audience; This paper presents the supercapacitor parameters variations due to state of charge (SOC), the number of cycle (NbCy) and frequency of DC-current in ambient temperature tests conditions. The goal of this study consists to show the parameters evolution which can serve to determine the lifetime of supercapacitor for different conditions of use. The contribution of the paper is focused on the impacts of DC-current frequency coupled to number of cycle on supercapacitor resistance and capacitance. The proposed method uses several DC-current profiles based on fluctuations and no fluctuations consideration. To do the supercapacitors characterization, the experimental tests based on charge and discharge operations with dynamic (fluctuating) DC-current are done. The experimental tests results are presented and the impacts of state of charge, the number of cycle and frequency of DC-current are analyzed.

This paper proposes an effective control strategy to enhance the Primary Frequency Control (PFC) capability of an offshore wind farm connected to the grid. A new nonlinear control method based on differential flatness properties of systems is applied to control the wind turbines in where, the control system is done by planning the appropriate trajectories on components of the output variables vector of the system. The PFC is assured by use of the energy reserve margins of the Wind Turbine Generators (WTGs). By starting from an imposed droop by the Transmission System Operator (TSO), news trajectories for the output variables of the system are generated and applied to the system control. Consequently, it allows the offshore wind farm to provide relief for the grid during depressed frequency conditions. Advantages of the proposed control method are in the one part, the simplicity of the system control strategy and in the other part, control and smoothing power of the wind farm during the transient state.

International audience; This paper presents energy management improvement for a Hybrid Electric Boat (HEB) using frequency approach. Diesel generator is assisted by supercapacitors and lithium-battery to satisfy energetic demand of hybrid electric boat. Supercapacitors and lithium-battery are linked to DC-bus through two bidirectional converters, and diesel generator is connected to DC-bus using three phase controlled rectifier. DC/AC converters connected to two electric motors are used as thrusters system which enables to emulate energetic demand of Hybrid Electric Boat (HEB) in propulsion operations. The power requirement of thrusters is added to embedded appliances demand to obtain load's profile. The contribution of this paper is focused on load's profile sharing between Diesel generator, supercapacitors and lithium-battery according to the dynamic responses of these sources. Proposed method performances are evaluated through some simulations using MATALB/Simulink software.

International audience; This paper presents modeling and control strategies of 5MW Permanent Magnet Synchronous Generator (PMSG) for offshore wind energy conversion application. The PMSG is connected to electrical grid of 20kV phase to phase RMS voltage using a back-to-back converter. The contribution of this paper is focused on energy management strategies using “grid code”, where the required power profile is fixed by electrical grid manager without any consideration for wind speed variations. For this study, it is assumed that the available power is higher than required power for electrical grid. The proposed control strategies include a Maximum Power Tracking (MPPT) for PMSG speed control, active/reactive power control, and DC-bus voltage management. To show the performances of the control, some simulation results are presented and analyzed using Matlab/Simulink software.

The main goal of this work is to develop specific procedures for implementation in wind turbine simulators designed especially for small machines. Using blade element methodology, we establish procedures for the torque and power characteristics of a small wind turbine, where some physical construction parameters are known. The algorithm is developed for two simulation procedures, which differ by the parameter used for the set of characteristics (wind speed or pitch angle).

The injection of wind farm production into a grid, needs optimal strategies for energy transfer management. Usually, the power produced by the wind farms does not fulfil all the grid code requirements. The main problem is generally based on the way to reduce the impacts of power production fluctuations on the grid voltage and its frequency. To solve this problem, some authors suggest the use of an interface such as energy storage devices in order to compensate the wind power fluctuations. In fact, the storage devices installed between the wind farm and the grid can improve the power quality in terms of stability but in other hand the size and the cost of the system can be increased. In this paper, two solutions have been proposed in case the power quality produced by the wind farm is out of the grid code requirements. The improvement of the energy quality of an offshore wind farm without storage and connected to the grid is discussed. The proposed solution is to operate the wind turbines with a reserve of power. To distribute this reserve equitably among wind turbines, a proportional distribution algorithms has been developed. The results obtained show clearly the effectiveness of the strategy.

International audience; This paper presents a comparative study between the frequency approach and dynamic component method for energy management in Hybrid Electric Vehicles (HEVs). An auxiliary energy system based on ultracapacitors (U), and the High Energy Storage system focused on lithium-battery are used to share the requested energy by a vehicle. Ultracapacitors are linked to DC-bus through a bidirectional converter, and the lithium-battery is directly linked to DC-bus without a converter. An inverter and Electrical Machine (EM) are used to emulate the energetic demand of the Hybrid Electric Vehicle (HEV). The contribution of this paper is focused on a HEV power sharing between the ultracapacitors and the battery according to the dynamic responses of the sources. The performances of the proposed methods are evaluated through some simulations and experimental tests using United States drive cycle.

This paper deals with errors inherent in modelling wind turbine simulators. Firstly, different wind turbine simulators are categorised. The work concerns simulators having a real-time soft simulator and an electromechanical tracking system, using any type of servomotor 15–17. Having presented the wind turbine linearised models, with respect to types of servomotor control (in speed or in torque), an analysis is made of simulator mathematical models and simulation performance evaluation, according to the dynamical behaviour of the electromechanical tracking systems. Next, the simulator performances calculation is presented, followed by a simulation error analysis for some particular cases, in order to highlight the differences between the speed and torque control structures. Finally, a servomotor choice principle is established, illustrated by numerical results obtained with the servomotor of a real time wind turbine simulator.

International audience; This paper presents the control strategies of an offshore wind energy system based on 5MW Doubly Fed Induction Generator (DFIG). The DFIG seems to be interesting for such high power wind generator systems. The proposed control strategies include the Maximum Power Tracking (MPPT) for the DFIG speed control, the active/reactive power control, and the DC-bus voltage control method. To show the performances of the control strategies, some simulation results are presented and analyzed using Matlab/Simulink software.

The interconnection of the wind generator (WG) and the diesel generator (DG) induces some interactions on the common coupling point. These interactions are studied in this paper with the aim of identifying the system limits in performance and proposing an alternative solution. Due to the fast fluctuations of the WG and the DG slow dynamics, ultracapacitors and batteries are used for improving the hybrid system performances and reducing the fuel consumption. The dc-bus voltage is controlled by the diesel engine while providing a smoothed current. To ensure optimized life cycle cost and performance, a lifetime-estimation-based method is proposed. In this method, a rainflow counting method is applied to size the storage devices by taking into account the actual conditions of the system operation. The experimental test bench is designed in a reduced scale. Some simulations and experimental results are presented and analyzed.

International audience; The DC distribution in the multisource systems seems to be a reasonable solution because the supplied energy is in the DC form for several sources, such as the photovoltaic panels (PV), the batteries, and the Ultracapacitors. Additionally, the major parts of the used electronics devises in the buildings operate with the DC current, such as computers, air conditioning, and multimedia. Based on these remarks, the authors propose an energy management method for the decentralized energy generation systems. The studied system includes the renewable energy sources (wind energy, and photovoltaic panels), the energy storage devices (lithium-battery, and Ultracapacitors), a programmable DC-Source for the Diesel generator behavior emulation, and the electronics load which emulate the electrical energy consumption in the building. Contrary to the previously works, the proposed control method is focused on the residential micro-grid energy management according to the dynamic responses of the sources and their availability. The performances of the method are evaluated through some simulations and the experimental tests, dedicated to residential micro-grid applications.

International audience; This paper presents the integration of the Fuel Cell (FC) and the SuperCapacitors (SC) in the distributed energy generation system such as the transport applications. This proposal is due to the present trend in the transport applications, knowing that the major drawback for these applications is the energetic autonomy problem. In this context, using the Fuel Cell and the SuperCapacitors with a performing energy management method is a promising solution to improve the energetic performances of the system. This paper presents the load's demand sharing between the SC and the FC in the traction situations. The proposed control method is implemented in the PIC18F4431 microcontroller for the reduced scale experimental test bench management. Through some experimental results, the authors present an improved energy management method for the transport applications during the tractions situations.

International audience; 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.

International audience; This paper presents an embedded energy share method between the high energy storage system (battery) and the auxiliary energy storage system such as supercapacitors (SC). Using the SC and battery with a good strategy for energy management improves the performance of hybrid electric vehicles (HEVs). The SC modules are dimensioned for peak power requirement, and the battery's module ensures the average power of HEVs. The battery module is connected to dc-bus through a dc/dc converter for the first topology and without a converter for the second configuration. Buck-boost converters are used between the SC and the dc-bus to manage the available energy for all topologies. The originality of this paper stems from its focus on the control methods of the dc-bus voltage and currents, which use adjustable polynomial controllers (correctors based on polynomial approach). These methods are implemented in the PIC18F4431 microcontroller which ensures analog to digital conversion, and the pulsewidth modulation signals generation for dc/dc converters. Due to cost and available components, such as the power semiconductors (IGBT) and the battery, the experimental tests benches are carried out in reduced scale. Through some simulations and experimental results, the performance of the proposed control is shown and analyzed.

Purpose – This paper aims to deal with the integration of energy storage devices (ultracapacitors) in wind energy applications to absorb the short terms fluctuations. The originality of this contribution is focused on energy management related to wind power frequency distribution between the hybrid sources. The robust and simplified control strategies are proposed and applied to DC‐DC converters without AC signals measurements. A novel MPPT method is introduced to operate the wind generator at the maximum power regardless of the wind speed variations. The fluctuating part of this power is mitigated by using a UC. The reference current of this last is obtained from a low pass filter. An innovative limitation algorithm of the UC voltage is proposed with aims to ensure optimal operation of the system. The control algorithms are implemented in a PIC18F4431 microcontroller. Some experimental results from this new approach are presented and analyzed.Design/methodology/approach – This study is organized accordin...

International audience; This paper deals the Battery-Supercapacitors energy management for Hybrid Electric Vehicles (HEV) applications. This idea is due to the present trend in the HEV applications, knowing that the major drawback in these last is the energetic autonomy problems. In this context, using Battery-Supercapacitors with a good strategy for embedded energy management is a promising solution to improve the system's performances. The main contribution of this paper is focused on DC-bus voltage and currents control based on the polynomial controller. The experimental control strategy is implemented in PIC18F4431 microcontroller for energy management through DC/DC converters. Through some simulations and experimental results obtained in reduced scale, the authors present an improved energy management strategy for HEV applications.

This paper presents a study related to a more efficient energy management between battery and Supercapacitors (SC) for Hybrid Electric Vehicle (HEV) applications. This idea is due to the present trend in the field, knowing that the major drawback of the HEV is the autonomy problem. Thus, using supercapacitors and battery with a good energy management strategy improves the HEV performances. The originality of this paper is focused on DC-bus voltage and currents control strategy based on polynomial controller. This strategy is implemented in PIC18F4431 microcontroller for DC/DC converters control. For reasons of cost and available components (no optimized) such as the battery and power semiconductors (IGBT), the experimental test bench is designed in reduced scale. Through some simulations and experimental results the authors present an improved energy management strategy for HEV.

International audience; This paper deals a new strategy for wind-diesel hybrid system energy improvement using Ultracapacitors (UC) and Battery. Energy management strategies are focused on the frequencies distribution of the wind generator current between UC and Battery. The developed control laws are based on the knowledge of the dynamic behavior of each source, in aim to prevent the diesel generator against the fluctuating currents while improving the battery's lifetime. The proposed strategies are implemented in the Microchip microcontroller (PIC18F4431) for experimental tests. Some experimental results obtained from this strategy are presented and analyzed.

International audience; In this paper, strategies of short and long term fluctuations mitigation are applied to a wind-diesel hybrid system. Ultracapacitors (UC) and batteries are operated in a complementary mode. The DC-bus voltage is maintained at a constant value by the diesel engine while providing a smoothed current. The proposed strategies are based on the wind power frequencies distribution between the storage devices (batteries and UC) using two low pass filters. Simulations and experimental results are presented and analyzed.

International audience; This paper deals the embedded energy share between Supercapacitors (SC) and batteries. SC modules are dimensioned for peak power requirement and batteries provide the power in steady state. This last is directly connected to the DC-bus to maintain the voltage level between 38V and 60V. A buck-boost converter is interfaced between the SC and the DC-bus to manage the available energy. The originality of this study is focused on energy management strategy between SC and batteries. The proposed strategy is based on polynomial (RST) controller. Due to cost and available components (no optimized) such as batteries and semiconductors, the experimental test bench is designed in reduced scale. The used packs of SC include two modules of 10 cells in series for each one, and present a maximum voltage of 27V. The buck-boost converters control algorithms are implemented in PIC18F4431 microcontroller. Experimental and simulation results obtained from polynomial control strategy are presented, analyzed, and compared to proportional integral ones.

International audience; This paper deals the supercapacitor (SC) and battery energy management in hybrid vehicle applications. The main goal of this study is based on embedded energy share between these sources using a full bridge converter topology. The originality of this paper is focused on full bridge converter control methodology for embedded energy management. The proposed strategy is based on classical PI controller. This strategy is implemented on PIC18F4431 microcontroller for full bridge converter control. For reasons of cost and existing components (no optimized) such as the planar transformer, the inductances, the batteries and power semiconductors (IGBT), the experimental test bench is designed in reduced scale. Some experimental results, obtained from this strategy are presented and analyzed.

International audience; This paper presents supercapacitor (SCAP) and battery modeling with an original energy management strategy in a hybrid storage technology. The studied dc power supply is composed of SCAPs and batteries. SCAPs are dimensioned for peak power requirement, and batteries provide the power in steady state. A bidirectional dc/dc converter is used between SCAPs and the dc bus. Batteries are directly connected to the dc bus. The originality of this study is focused on SCAP behavior modeling and energy management strategy. The proposed strategy is based on a polynomial (RST) controller. For reasons of cost and existing components (not optimized) such as batteries and semiconductors, the experimental test benches are designed in reduced scale. The characterized packs of SCAPs include two modules of ten cells in series for each one and present a maximum voltage of 27 V. The proposed strategy is implemented on a PIC18F4431 microcontroller for two dc/dc converter topology controls. Experimental and simulation results obtained from the polynomial control strategy are presented, analyzed, and compared with that of classical proportional-integral control.

The study of behaviour of the hybrid power systems (HPS) for remote areas is one of research axes of our laboratory. Simulink blocks with models corresponding to all the system parts have been developed. Control laws have been implemented to ensure the optimal power retrieval, the system stability and the output power quality. In order to make possible the models and the control laws validation, a small scale HPS (1:100 of power) is under construction. It is composed of renewable sources (a wind turbine generator and photovoltaic panels), buffer batteries, DC/DC and DC/AC converters, diesel generator and load/faults emulator. For the system development some stages is necessary. Beginning with a simple starting structure, in every step a part is added or changed and the system operation is verified