Papers by Ibtissam Lachkar
Nonlinear Control of Double Stage Three-phase Grid-Connected Photovoltaic Systems
IFAC-PapersOnLine
Backstepping Control and Adaptive Observer Design for a Single-Phase Grid-Connected Photovoltaic System
IFAC-PapersOnLine
Advanced Control of Single-Phase Shunt Active Power Filter Based on Flying Capacitor Multicell Converter
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Towards a global nonlinear control strategy for DFIG-based wind turbine in a high wind energy penetrated system
International Journal of Modelling, Identification and Control
MPPT-based backstepping control for a grid connected fuel cell system using high step-up converter
International Journal of Modelling, Identification and Control
Nonlinear Control Design and Stability Analysis of Single Phase Half Bridge Interleaved Buck Shunt Active Power Filter
IEEE Transactions on Circuits and Systems I: Regular Papers
This paper deals with nonlinear control of a single-phase half-bridge interleaved buck shunt acti... more This paper deals with nonlinear control of a single-phase half-bridge interleaved buck shunt active power filter (HBIB-SAPF) with a nonlinear load. The control objective for the system is twofold: performing power factor correction by compensating for harmonics and reactive current consumed by the nonlinear load from one hand and tightly regulating the HBIB converter DC capacitor voltage. Both objectives are accomplished using a two-loop nonlinear controller. The inner loop acts on the switching devices so that the active filter current tracks its reference with the aim of ensuring a unity power factor. This loop is tackled using backstepping technique and Lyapunov approach. The outer loop is responsible for regulating the DC capacitor voltage to its desired value, using a PI controller with a pre-filter. The stability analysis of the closed-loop system is formally performed by using the averaging theory. The validity of the designed nonlinear controller is checked by simulations in Matlab/SimpowerSystem showing its robustness and accuracy under various operating conditions.
Nonlinear control of interleaving boost AC/DC converters: Output voltage regulation and power factor correction
2018 5th International Conference on Electrical and Electronic Engineering (ICEEE), 2018
This article presents a single-phase power factor correction (PFC) circuit for AC-to-DC converter... more This article presents a single-phase power factor correction (PFC) circuit for AC-to-DC converter using an interleaved boost converter (IBC), leading to improve the input power factor (PF), reducing the input current harmonics and decreasing the number of needed active switches. The control objectives are twofold: (i) guaranteeing a tight regulation of the DC output voltage to a desired reference value, (ii) assuring a unitary power factor by imposing the voltage and the current delivered by the electric network to be in phase. The studied problem is dealt by designing a cascade-structure nonlinear controller. The inner loop of the latter ensures the PFC objective; it is built-up using the backstepping design approach that is developed making use of the Lyapunov control design technique. The outer loop regulates the converter squared output voltage employing a filtered PI regulator.
Commande non-linéaire avancée d'un compensateur statique synchrone: analyse théorique des performances en boucle fermée
International audienc
Flatness-Based Control of DC Machine-Serial Multicellular Power Converter Association
Recent Advances in Electrical and Information Technologies for Sustainable Development, 2019
This chapter considers the control of serial multicellular power converter feeding DC motor. For ... more This chapter considers the control of serial multicellular power converter feeding DC motor. For this purpose, a new control strategy based on flatness approach is developed. The main aim consists on regulating the DC motor velocity to a desired level, keeping in mind the necessity of ensuring an equitable distribution of the supply voltage on the power switches of serial multicellular power converter. To this end, the regulation of the voltage at the terminals of the flying capacitors is necessary. The synthetized controller was verified by computer simulation using Matlab/SimPowerSystems, and the obtained results prove the effectiveness of the designed controller and show that the entire objectives are achieved.
Nonlinear Control of Active and Reactive Power in Grid-tied DFIG-WECS
2020 International Conference on Electrical and Information Technologies (ICEIT), 2020
This paper proposes a stator powers control of a grid-connected doubly fed induction generator-wi... more This paper proposes a stator powers control of a grid-connected doubly fed induction generator-wind energy conversion system (DFIG-WECS) based on sliding mode control (SMC) technique. The aim is to design a nonlinear controller in the generator side to guarantee that the stator active power tracks the maximum available power provided by the MPPT strategy and maintain the reactive power at a desired reference. In the grid side, PI controllers are used to regulate the DC-link voltage at a given reference value in the outer loop, and two internal loops are used for controlling the dq-axis currents. The proposed control scheme for 2MW grid-connected DFIG system is tested in Matlab/SimPowerSystems environment under fixed steps and variable wind speed. The obtained simulation results prove the efficiency of the suggested controller.
IFAC-PapersOnLine, 2020
In this paper, an advanced nonlinear backstepping control approach is developed and applied to th... more In this paper, an advanced nonlinear backstepping control approach is developed and applied to the whole nonlinear system including the AC/DC/AC converters combined with the doubly-fed induction generator(DFIG). A high gain observer is synthesized, in order to provide an estimated value of the mechanical torque whereas, a wind speed estimation block is designed based on roots polynomial method; followed by sensorless maximum power point tracking (MPPT). The control objectives are fourfold: (i) Forcing the generator speed to track the reference signal given by the MPPT block, (ii) adjusting the stator reactive power injected into the grid to be null, (iii) Regulating the DC-link voltage between the rotor side and the grid side converters at the desired level, (iv) assuring a unitary power factor in the grid side. The achievement of these control objectives leans on a multi-loop regulator which shows a satisfying performance as far as it concerns the simulation results.
Modeling and Control of a Wind Turbine Based On a Doubly Fed Induction Generator
2019 4th World Conference on Complex Systems (WCCS), 2019
In this paper, the (DFIG) for wind energy conversion system is studied so as to control the rotor... more In this paper, the (DFIG) for wind energy conversion system is studied so as to control the rotor speed and the reactive power produced by the (DFIG). To achieve these objectives, a decoupling control scheme has been applied utilizing PI controllers. In the DFIG topology, the stator is specifically associated with the grid and the rotor winding is associated with the grid through an AC/DC/AC converter. First, we propose the mathematical model in Park's coordinates of the whole system. Next, a field oriented control for decoupling the torque and the reactive power is applied. Finally, the DC Link voltage is regulated at a well defined constant value. This work is developed and programmed using Matlab/Simulink environment. The obtained simulation outcomes demonstrate the effectiveness of the suggested controller.
IFAC-PapersOnLine, 2020
The present paper discusses the modelling and the nonlinear control of a DC/AC conversion system ... more The present paper discusses the modelling and the nonlinear control of a DC/AC conversion system composed of photovoltaic arrays, boost converters, DC bus capacitors, N-cascaded H-bridge multilevel inverters (CHBMI) and an L-filter linked to a single-phase grid. This work aims at achieving threefold control objectives: i) regulating the voltages across the PV panels in order to extract the available maximum power, ii) guaranteeing a unitary power factor (UPF) by forcing the grid current to be sinusoidal and in phase with the electric network voltage, iii) controlling the DC-link voltages to track their given references. The achievement of these objectives is done thanks to a regulator based on a multi-loop structure. Indeed, on one hand, each panel is individually controlled to track the maximum power point; on the other hand, two cascaded loops aim at ensuring a satisfactory power factor correction and DC-link voltages regulation. The proposed regulator is developed using the nonlinear backstepping approach and some tools from Lyapunov stability. The simulation results, obtained using MATLAB/SIMULINK/ SimPowerSystems environment, prove that the synthesized regulator meets its objectives and presents interesting performance in terms of tracking and regulation.
Universal Journal of Electrical and Electronic Engineering, 2019
This paper focuses on the problem of controlling single-phase shunt active power filters (APFs) o... more This paper focuses on the problem of controlling single-phase shunt active power filters (APFs) operating in the presence of nonlinear and uncertain loads. The main difficult ies when controlling this kind of filter are the existence of a strong non-linearity of the system and state variables inaccessible to measurements. This paper proposes a double-loop cascade controller developed on the basis of the singular perturbation technique in order to meet t wo main control object ives: (i) the inner-loop is designed to compensate the harmonic and reactive currents absorbed by the nonlinear load enforcing power factor correction; (ii) the outer-loop is synthesized to regulate the inverter output capacitor voltage. The controller also includes two-time scale sliding mode observer to estimate the network voltage that is not accessible to measurement. In this work, the singular perturbation technique and averaging theory are used for a co mplete and rigorous formal analysis to describe the control system performances. The effectiveness of this approach has been successfully verified through computer simu lations using the Matlab/Simulink environment.
Flatness based control of multicellular power converter feeding DC motor
2017 International Conference on Electrical and Information Technologies (ICEIT), 2017
In this paper, a new control strategy of a multicellular converter (three cells) is proposed in o... more In this paper, a new control strategy of a multicellular converter (three cells) is proposed in order to drive a DC machine, there were two main goals to achieve: i) ensure a suitable distribution of flying capacitors voltage which implying the regulation of voltages across capacitors, ii) regulating DC motor velocity to a desired level. The proposed system is described by 4th order nonlinear mathematical model. To stabilize the global system and realize the above objectives, a controller based on differential flatness approach is synthesized in order to control this system. The simulation results have been performed through Matlab/SimPowerSystems environment and show that the designed controller meets its objective.
Advanced sensorless nonlinear control and stability analysis of single-stage PV systems connected to the grid via a 3L-NPC inverter
European Journal of Control
Advanced Statistical Modeling, Forecasting, and Fault Detection in Renewable Energy Systems
This chapter addresses the problem of controlling single-phase grid-connected photovoltaic system... more This chapter addresses the problem of controlling single-phase grid-connected photovoltaic system through a full bridge inverter with L-filter. The control objectives are threefold: (i) forcing the voltage in the output of photovoltaic panel to track a reference. This reference has been obtained from the maximum power point tracking strategy; (ii) guaranteeing a tight regulation of the DC-link voltage; and (iii) ensuring a satisfactory power factor correction (PFC) at the grid such as the currents injected must be sinusoidal with the same frequency and the same phase as the grid voltage. The considered control problem entails several difficulties including: (i) the high dimension and strong nonlinearity of the system; (ii) the changes in atmospheric conditions. The problem is dealt with by designing a synthesized nonlinear multi-loop controller using singular perturbation technique, in which a three-timescale dynamics is artificially induced in the closed-loop system. A formal analysis based on the three-timescale singular perturbation technique and the averaging theory is developed to proved that all control objectives are asymptotically achieved up to small harmonic errors (ripples). The performance of the proposed approach and its strong robustness with respect to climate changes are evaluated based on the various simulations results carried out under Matlab/Simulink software.
Adaptive Control and Formal Stability Analysis of Single-Phase Flying Capacitor Multicell DC-AC Inverters
International Review of Automatic Control (IREACO)
Adaptive nonlinear control of multicellular single phase inverter
2017 IEEE International Conference on Smart Energy Grid Engineering (SEGE), 2017
We are considering the problem of controlling a single-phase Multicellular inverter with LC outpu... more We are considering the problem of controlling a single-phase Multicellular inverter with LC output filter. The control objectives are: (i) generating a sinusoidal voltage with amplitude and industrial frequency fixed by the reference signal, (ii) ensuring a good convergence of the voltages across the flying capacitors. The controller is designed using the backstepping approach in its adaptive versions and the Lyapunov stability argument. Unlike the existing formulations, the approach also gives additional analysis based on averaging theory. The adaptive version is designed and presented to produce quite interesting tracking and robustness performances with respect to load variations as it is shown by simulation result in Matlab/Simulink.
Output Feedback Adaptive Control Strategy of the Boost Inverter
2019 4th World Conference on Complex Systems (WCCS), 2019
In this work, the focus is put on the issue of controlling a single-phase single stage Boost Inve... more In this work, the focus is put on the issue of controlling a single-phase single stage Boost Inverter by an output feedback adaptive control. The main goal of this study is to provide a sinusoidal output voltage which follows tightly the desired reference. The considered control problem is permeated by many difficulties in terms of: (i) The nonlinearity of the studied circuit topology; (ii) The presence of the phenomenon of non-minimum phase makes the system difficult to control; (iii) Inaccessibility to measurements of all currents; (iiii) Unknown load. The issue is dealt using an indirect output voltage regulation: (i) An inner loop is designed using output feedback adaptive control based on the observer with a view to estimating the state variables (Currents); (ii) An outer loop regulates the output voltage to track its reference. The simulation outcomes have been corroborated within Matlab/Simulink/Simpowersystems, which demonstrate that the suggested controller achieves the desired aim.
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Papers by Ibtissam Lachkar