Mohamed Faouzi Mimouni

A backstepping control strategy applied to the connected hybrid renewable energy system operated in MPPT

In this paper, an interconnected grid hybrid renewable energy system, HRES, (wind/PV) is studied. The wind energy conversion system, WECS, is constructed aroud a wind turbine coupled to a double fed induction generator, DFIG. The stator of DFIG is directly connected to the grid and the rotor is connected to the grid through back-to-back power converters. To control the wind system, we have applied the adaptive backstepping control strategy for both converters. The PV energy system is composed by PV cell energy and the DC-DC boost converter. To control the DC-DC boost converter, we have applied tow cascade PI control loop. The first one is used to regulate the output current or the second one is used to control the output voltage. We have considered in both control structure the MPPT algorithm. To study the comportment of the HRES against the environment changes, we have considered some simulations scenarios for the wind speed, the irradiance and the temperature. We have studied the dynamic performances of the proposed control strategy.

Robustness analysis and evaluation of a PMSG-based marine current turbine system under faulty conditions

This paper deals with a Permanent Magnet Synchronous Generator (PMSG) driven by a Marine Current Turbine (MCT) through a PWM power rectifier and used for isolated sites. The generator model is established in the synchronous rotating dq reference frame. The control of the speed, the d-axis current, and the q-axis current is achieved using PI correctors. Robustness and performance of the considered system are evaluated in healthy and faulty conditions. The faulty mode deals with the study of single and multiple open-switch damages appearing in the PWM power rectifier. Simulations are carried-out to highlight the proposed PMSG-based MCT performance in both cases.

Nonlinear vector control strategy applied to a variable speed DFIG generation system

We present in this paper the modeling and control designs for a variable-speed constant-frequency wind energy conversion system using double fed induction generator. The aim of this paper is to develop a nonlinear vector control strategy using the second Lyapunov approach for the rotor side converter and a network voltage vector oriented control of the grid side converter and to maximize the energy captured from the wind turbine and injected to the grid. Simulation results of a DFIG generation system have shown good performances of the system under the proposed control strategy.

Strategy of energy control in PVP/battery water pumping system

Pumped storage is generally viewed as the most promising technology to increase renewable energy source penetration levels in power systems and particularly in small autonomous systems. Combined battery and pump constitute a realistic and feasible option to achieve high penetrations. This paper focuses on dynamic modeling, simulation, control and energy management in an isolated integrated power generation system consisting of a 2 kW PV and 100 Ah lead acid battery storage. A supervisory controller is designed for energy management between the maximum energy captured from the PV and consumed energies of the load. Dynamic modeling and simulation are fulfilled using MATLAB Simulink™7.2.

Implementation on the FPGA of DTC-SVM Based Proportional Integral and Sliding Mode Controllers of an Induction Motor: A Comparative Study

The conventional direct torque control (DTC), based on the hysteresis controllers and the switching table, operates with a variable switching frequency, which decreases the conventional DTC performances, like the torque and flux ripples. Thus, the space vector modulation (SVM), used in the DTC, ensures a constant switching frequency and improves the DTC performances. The first aim of this paper is to present a comparison study between the DTC with an SVM (DTC-SVM) based on the Proportional Integral regulators (DTC-SVM-PI) and the DTC-SVM based on the sliding mode controllers (DTC-SVM-SMC). These two approaches are complex control algorithms which require faster micro-controllers; therefore the second objective of this paper is to present the implementation of the DTC-SVM-PI and the DTC-SVM-SMC on the Field Programmable Gate Array (FPGA), due to the parallel processing capability of the FPGAs. The two approaches are designed and simulated using the Xilinx System Generator (XSG) and implemented using an FPGA Virtex 5. The simulation results in the transient behavior and the steady state of the induction motor controlled by these two approaches are compared and discussed. The hardware FPGA implementation results show the effectiveness of the FPGA relative to the digital signal processor in terms of execution time.

A sliding mode control approach applied to a photovoltaic system operated in MPPT

In this paper, the modeling and control of a photovoltaic system is presented. A maximum power point tracking (MPPT) algorithm is adopted to maximize the photovoltaic output power. The proposed approach for peak power tracking using the sliding mode control is robust to environment changes (irradiance and temperature). Simulation results using Matlab/Simulink have shown good performances of the photovoltaic system operated in MPPT.

Classical vector, first-order sliding-mode and high-order sliding-mode control for a grid-connected variable-speed wind energy conversion system: A comparative study

This article proposes a comparative study between different control strategies of a wind energy conversion system. It aims to guarantee a robust control strategy which gives a good performance despite the external disturbances. Studied system comprises a wind turbine, a permanent magnet synchronous generator, and two converters linked by a DC bus. The whole is connected to the grid through a resistor–inductor filter. A classical vector control based on proportional–integral controller is applied to our system. Owing to the sensitivity of this control against external disturbances, a control strategy using first-order sliding mode has been proposed. This strategy provides good performance, such as insensitivity to non-linearity of system. Yet, the theory of first sliding mode has faced the problem of chattering, which proved to be a major drawback. To overcome this problem, a control strategy using sliding mode of higher order was implemented on the basis of the super-twisting algorithm.

Model predictive control for hybrid battery/ultracapacitor power supply used in vehicular applications

All hybrid electric systems require a strategy of energy management to share out the flow of energy between its several sources or storage devices. In this work we propose a constrained Model Predictive Controller to distribute the energy in a battery/ultracapacitor hybrid system. The studied system is used as a power supply/storage system in electric and hybrid electric vehicles and the proposed controller allows to satisfy load demand taking into account dynamic and technical constraints of sources and converters and to maintain at the same time the output voltage to the desired value of 42 V. The effectiveness of the control strategy which makes possible to solve real time optimization problem with soft and hard operation constraints is verified using Matlab®\Simulink®.

A real-time control of photovoltaic water-pumping network

Display Omitted A modeling and simulation of photovoltaic water-pumping network are affected.An energy management and a control strategy of the system are presented.A real time control of photovoltaic water-pumping network system is proposed.The optimization of the pumped water and the tanks regulation were ensured.An adequate maximum power-point tracker should be controlled. In this paper a dynamic modeling, simulation, control and energy management of photovoltaic water-pumping network system is presented. A fuzzy-logic controller has been proposed for a real-time control of the system. The controller generates the reference speeds needed for the pulse-width-modulation generator to control each DC/DC boost converter taking into account the water levels in three tanks and the instantaneous value of the solar radiation. The main objectives of the fuzzy-logic controller are the design of an adequate maximum power-point tracker to extract the maximum power, regulate the water in the three tanks and finally ensure the correct operation for all the conversion strings in order to optimize the quantity of pumped water. The system performance under different scenarios has been checked carrying out Matlab/Simulink simulations using a practical load-demand profile and real weather data and comparing them to another control algorithm.

Determination of the target speed corresponding to the optimum functioning of a photovoltaic system pumping and regulation of the water level

This paper deals with the problem of the water level regulation in the photovoltaic pumping system. To achieve this aim, a fuzzy logic controller has been developed in order to determine the reference speed needed for vector control of asynchronous motor taking into account the water level in the tank and the variation of solar irradiation. The mathematical model of the regulation of water level is built on the basis of Matlab-Simulink.