Rabeh Abbassi

Improvement of the integration of a grid-connected wind-photovoltaic hybrid system

This paper presents control strategies for the integration of a grid-connected wind-photovoltaic hybrid system via adaptation converters connected to a common DC bus. For both wind and solar system, adequate control algorithms have been implemented for the maximum power extraction. The grid side converter has been connected to the point of common coupling (PPC) through an RL filter. The control of the grid side converter (GSC) was made in order to control the power quality and quantity of the feed power to the grid. At the DC bus, a PI-regulation control was adopted to overcome the ripples caused by the power flow. Performances of the adopted control laws have been evaluated by MATLAB/Simulink simulations.

Optimal energy management strategy for wind photovoltaic hybrid system with battery storage

This paper proposes control strategies for a grid connected Hybrid System (WPVHS) composed of wind turbine photovoltaic array and storage system. The aim is to ensure the service continuity despite the fluctuating behavior of the renewable sources by using a batteries storage system. The proposed control scheme is based on the power balancing in the common DC-link. Hence, the Hybrid System is able to inject desired active and reactive power to the electrical grid. MATLAB software simulation results are provided in order to demonstrate the performance and to show the feasibility of the proposed control.

Power quality improvement using VF-DPC-SVM controlled three-phase shunt active filter

The main focus of this paper is to present a novel and simple direct power control of shunt active power filter with constant switching frequency using space-vector modulation (DPC-SVM). Also, the AC line voltage sensors with a virtual flux (VF) estimator are replaced. This control method is applied to eliminate harmonic pollution and compensate the reactive power in the presence of nonlinear loads and unbalanced sources. The control system is resistant to the majority of line voltage disturbances using by the idea of virtual flux and phase locked loop (PLL) approach. The superior advantages of this method are simple algorithm, good dynamic response, constant switching frequency and resistant to the majority of line voltage disturbances. The simulation results, using Matlab/Simulink, are presented to show the validity of the proposed model, and to evaluate the performance of the control strategy.

Adaptive-fuzzy hysteresis controlled three phase shunt active filter for constant switching frequency

The study done in this paper concerns the use of a new control technique of current using adaptive hysteresis regulator by fuzzy logic on the command of a parallel active filter. For the proposed method, the hysteresis band is adapted in every moment in order to determine the switching frequency and control the position of the command pulses. This allows a better tracking of a heavily distorted current and minimizes undulations in the various quantities characterizing the active power filter. In this paper, the theory of the method is discussed and its performance is compared, though out simulations, to the adaptive band technique. The comparative study confirms the benefits and potentiality of the new modulation method.

New approach for minimizing the harmonic currents in power systems

The objective of this paper is to develop a new identification algorithm for the disturbance currents through the combination of a multi-variable filter (MVF) with the theory of instantaneous powers (PQ-MVF). The MVF exploits the transform of Concordia and ensures the selective or global extraction of harmonic current references. Consequently a shunt active filter (SAF) based on the MVF can compensate for fully or partially the disturbance especially when the fault appears. The obtained results show the superiority of the proposed algorithm compared with conventional identification methods, especially in terms of performances when the source voltages are unbalanced and / or distorted.

Solar photovoltaic energy system-based shunt active filter for electrical energy quality improvement

This article presents a harmonic compensation system using a photovoltaic generator (GPV) to improve the supply power quality. The proposed configuration is constituted by a grid connected three-phase inverter, a PV array and a nonlinear load formed by a bridge rectifier feeding a resistive load in series with an inductor. An indirect current control via the method of active and reactive power is proposed to compensate the harmonic currents and reactive power at the point of common coupling while injecting active power from the solar system to the grid. The perturb and observe (P&O) method has been applied to track the maximum power point. The proposed system simulation under MATLAB/Simulink environment proves the robustness of the proposed control approach that simultaneously guarantees the compensation of harmonic currents, the correction of the power factor and the injection of PV power to the grid.

Passivity-Based Direct power control of Shunt Active Filter under Distorted Grid Voltage Conditions

Despite its many advantages, the conventional direct power control (DPC) of shunt active power filters (SAPF) poses some problems. This paper investigates the design of a new control technical combining DPC control and passivity theory (PT) to ensure quasi-sinusoidal grid currents, under various conditions of the source voltages. The proposed approach (DPC-PT) appeals to the theory of symmetrical components (negative and positive) to solve the problem of disturbed voltages signals during a grid imbalance. The implantation of the DPC-PT methodology was developed under Matlab/Simulink environment. Simulation results showing the operation and performances of the SAPF in steady and transient states have been presented. The found results show the satisfactory dynamic response and the improvement of network behavior in the presence of an imbalance.

Novel flexible algorithm for the operation of renewable source grid interface VSCs under unbalanced voltage sags

This study deals with a newly-conceived control strategy for three-phase grid connected VSIs used for distributed generation (DG) system with renewable energy sources. This strategy has been called SCCA (Symmetrical Component Control Algorithm). The SCCA aims that DG power plants can avoid overcurrent while helping to mitigate the adverse effects of unbalanced voltage sags for continuous operation. For this, it accomplished simultaneously the control of the injected currents and active and reactive power flow. A simulation comparison among five published methods and SCCA is presented in terms of quality of the injected current and ripple of the injected powers. The extensive MATLAB/Simulink simulation studies of SCCA concept demonstrate that the proposed strategy outperforms the majority of already published strategies in terms of the above criteria.

Control of a double fed induction generator (DFIG) connected to an unbalanced electrical grid

The electrical supply grids can be the seat of an unbalance of voltage system following the single-phase loads which are connected and which are not uniformly distributed on the three phases. We propose, in the present paper a new approach to control a power system based on a double fed induction generator (DFIG) connected to an electrical grid likely to be affected of an unbalance voltage, via a back-to-back converter (AC/AC). The head aim is to guarantee a better quality of the energy exchanged between the power system and the unbalanced grid.

Control of a Permanent Magnet Synchronous Machine (PMSM) connected to an unbalanced electric grid

The quality of the electric power produced, transported and distributed did not cease being a major concern for the operators and the manipulators of electricity. Several disturbances of various natures are at the origin of instabilities of the electrical supply networks]. Among the disturbing phenomena, we quote the unbalance voltage of which we were interested by proposing an adequate command and control of a Permanent Magnet Synchronous Machine (PMSM) when this one output on the network. In fact, the unbalanced electrical grid voltage has due direct to the earthed grids which are connected to it. This unbalance has harmful effects on operation of the electric machines. We thought to study the control of a permanent magnet synchronous generator (PMSM) in the presence of such phenomenon