Miloud Rezkallah

Lyapunov Function and Sliding Mode Control Approach for the Solar-PV Grid Interface System

This paper deals with control of a solar-photovoltaic (PV) power-generating system interfaced with the grid. A sliding mode control approach is used for achieving maximum power tracking control of a solar-PV array. The Lyapunov function-based control approach is designed and modeled for the dc-ac inverter to serve the functions of an active power injection to the grid, balanced grid currents at unity power factor and load currents harmonics compensation. The proposed approaches eliminate the need of adjustment of system parameters under changing loads and generation scenario. The effectiveness of the proposed control strategies is established using its stability analyses. The performance of the solar-PV power-generating system with the proposed control algorithms is demonstrated using simulation and experimental studies under various operating conditions.

Control of wind-diesel isolated system with power quality improvement

This paper presents the modeling of the wind-diesel stand alone system without energy storage with two control algorithm of the shunt active filter (AF) to compensate the current harmonics and the power factor of nonlinear load. A 3 - phase voltage source inverter bridge with a dc bus capacitor is used as an active filter. The active filter is controlled by two strategies; indirect current control and d-q reference frame technique which uses a decoupled nonlinear control strategy. The Matlab/Simulink results under different conditions are presented and discussed.

Vector control of squirrel-cage induction generator for stand-alone wind power generation

This paper deals with a variable speed induction generator supplying autonomous loads. The squirrel cage induction generator (SCIG) is connected to the load through back to back connected voltage source converters (VSCs) and the system is reinforced by a battery storage in order to keep the frequency and voltage constant during the variation of the loads and wind speeds. The reactive power for setting up magnetic field in this generator is drawn from the VSC. A dc-dc converter is used between back to back connected VSCs to control the battery and is maintain dc bus voltage constant. The generator torque is controlled by the generator side VSC using a field oriented control and the voltage of load side is controlled by the load side converter by means of simple d-q control. The effectiveness of the proposed system is verified using MATLAB/SIMULINK software and the results are presented and discussed for various operating conditions.

Wind diesel battery hybrid system with power quality improvement for remote communities

This paper presents a control strategy for the hybrid wind diesel with battery storage in isolated network. The proposed strategy consists of dc/dc bidirectional converter for charging/discharging battery to keep the frequency at the PCC constant by consuming/providing the extra active power delivered by the wind turbine. The battery is also used to feed the loads when the speed of the wind is too low to improve the efficiency of the installation by reducing the power delivered by the diesel engine. The control technique known as pq theory is used to control the interfacing inverter to perform the desired tasks. The proposed use of strategy compensates the current harmonics, the reactive power and the unbalance load. The entire system is realized and simulated in MATLAB/SPS environment. The results under various conditions are presented and discussed.

Three-leg four-wire voltage source inverters for hybrid standalone system feeding unbalanced load

This paper presents a new design and control for HWDBS (Hybrid Wind-Diesel-Battery System) feeding three-phase four-wire local loads. The proposed system consists of two energy sources connected to the dc bus; a WT (Wind Turbine) and a DE (Diesel Engine) based on variable speed generators. The system utilizes two back-to-back connected converters and uncontrolled three-phase converter connected in cascade with dc-dc SEPIC converter. The system uses BESS (Battery Energy Storage System) placed at the dc bus to manage the exchange of power between the energy sources and the loads. The VSC (Voltage Source Converter) of WT side is controlled in order to achieve maximum power tracking by varying the rotor speed of the SCIG (Squirrel Cage Induction Generator). In order to improve the control performance and to reduce the cost of SCIG, the MRAS (Model Reference Adaptive System) speed observer based on stator voltage and currents is adopted. The DE is controlled in order to balance the power of the system by changing its speed according to the load power demand and to minimise the fuel consumption. DE is switch off when the WT power is greater than the load power demand. The main objective of the interfacing load side VSC is to achieve a constant voltage and frequency and to compensate unbalance using symmetrical components of the load currents. The proposed system is studied for various types of linear, nonlinear and dynamic loads and under varying wind speed conditions. The dynamic behavior of the proposed system is verified using MATLAB/SIMULINK.

Design and Implementation of Active Power Control With Improved P&O Method for Wind-PV-Battery-Based Standalone Generation System

In this paper, the design and implementation of active power control with antiwindup PI controller (AWPI) and improved perturbation and observation (P&O) method with sliding mode control (SMC), are investigated to get a high level of performance with a reduced number of sensors for a stable operation of a wind-PV-battery-based hybrid standalone power generation system (HSPGS). The SMC approach with boundary layer is used for an optimum trajectory on the sliding surfaces, with variable operating conditions of many power converters connected at the same DC bus. Furthermore, detailed modeling and stability analysis to demonstrate the transversality, reachability, and equivalent control are presented. The effectiveness and robustness of HSPGSs and their respective control strategies are validated by simulation and test results on a hardware prototype using a DSP-dSPACE real time controller.

Implementation and control of small-scale hybrid standalone power generation system employing wind and solar energy

This paper presents an implementation and control of a hybrid standalone power generating system (HSPGS) based on a wind turbine (WT) and a solar-photovoltaic (PV) array. A squirrel cage induction generator (SCIG) is coupled with a WT for electromechanical energy conversion. The frequency and amplitude of voltage at AC bus, as well as, power quality improvement at the point common coupling (PCC) are achieved by controlling the three-leg voltage source converter (VSC) using decoupled nonlinear control algorithm. A battery energy storage system (BESS) is reinforced in the hybrid system to ensure power leveling under wind, solar and load fluctuations. For obtaining the maximum power from a solar PV array and to regulate the output DC voltage, a DC-DC boost converter is controlled using perturbation and observation technique. Moreover, a dump load is tied at DC bus to ensure stability of control and to protect the BESS and solid state switches from overvoltage at DC bus during the period of fully charged battery. The proposed HSPGS and its control algorithms are modeled in MATLAB/Simulink and its performance is tested in real time under presence of balanced/unbalanced, linear/nonlinear loads and change in climate conditions.

Control of small-scale wind/diesel/battery hybrid standalone power generation system based on fixed speed generators for remote areas

In this paper control design for safe and effective operation of small-scale hybrid wind/diesel/Battery standalone power generation system (WT-DG HSPGS) employing fixed speed generators is investigated. To compensate the fluctuation of wind power, reduce the run-time of the diesel generator (DG), regulate the AC voltage and the system frequency, as well as, to improve the power quality at the PCC, STATCOM supported by battery energy storage system (BESS) is controlled employing synchronous reference frame (SRF) theory and estimated in-phase and quadrature unit AC voltage templates. To synchronize the DG to the PCC, breaker switch is controlled using the estimated voltage phase angle and the system frequency. To protect BESS from overcharging, dump loads is controlled using simple approach based on BESS limit charging voltage. To test the performance of the proposed WT-DG HSPGS and their developed control algorithms under presence of balanced/unbalanced, linear/nonlinear loads and change in climate conditions, simulations are carried out using MATLAB/Simulink.

Hybrid standalone power generation system using hydro-PV-battery for residential green buildings

This paper deals with control of hybrid standalone power generation using micro-hydro power turbine (MHP) coupled with a squirrel cage induction generator (SCIG) and a solar photovoltaic panel (PV), which is connected to the common DC bus of three-phase voltage source converter (VSC). The AC terminals of VSC are connected to point of common coupling (PCC) through interface inductors. A battery energy storage system (BESS) is also tied with the common DC bus through a buck-boost converter. The proposed system is mostly suitable to serve the power needs of any small size residential green building situated near a small river or cannel. Control algorithms are proposed for the three-phase VSC and the DC-DC buck-boost converter in order to extract the maximum power from PV array with single-stage conversion, to regulate the AC voltage and frequency at PCC and to improve the power quality. The effectiveness and the robustness of proposed controllers are validated by simulation using Matlab/Simulink at linear and nonlinear loads under different climate conditions.

Microgrid: Configurations, Control and Applications

This paper deals with a comprehensive study of configurations of microgrid (MG) based on variable speed generators. The selection criteria for these configurations along with the design of required control algorithms, are presented in detail. Simulation results and experimental validation of selected MG configurations are given to demonstrate their suitability. It is aimed to enhance applications of MGs with main emphasis on renewable energy sources to ensure sustainable development in rural and remote areas.