Maissa Farhat

A stable FLC-based MPPT technique for photovoltaic system

This paper presents a new stable fuzzy-logic-control (FLC) based maximum power point tracking (MPPT) algorithm for stand-alone photovoltaic (PV) system. The proposed method uses the power to voltage variation and voltage variation as the inputs, which significantly simplified the computation. The proposed FLC is compared in the simulation with the conventional perturb and observe (P&O) method, the FLC-based MPPT algorithm improved the dynamic and steady state performance of PV system. The rules set up were established in order to ensure the system stability. The stability analysis method for the mamdani fuzzy logic controller is proposed using the Lyapunovs theory. The obtained results show that the proposed (FLC) succeeds to track the MPPT and present better performance compared to the P&O.

Variable structure MPP controller for photovoltaic pumping system

This work is oriented to research performance in terms of optimal transfer of energy from a photovoltaic generator to a permeant magnet synchronous motor type used as a centrifuge pump driver. The performance improvement is done using a variable structure controller with sliding mode as a maximum power point tracker (MPPT). A stability analysis for the proposed MPPT is developed for a photovoltaic (PV) pumping system. The global stability of the variable structure algorithm is demonstrated by means of Lyapunov’s approach. The tracking algorithm leads the PV generator coordinates to the maximum power point by changing the pulse width modulation (PWM) signal frequency of the boost converter. The steady-state behaviour of the PV pumping system with variable structure control is characterized by a stable oscillation around the maximum power point. The effectiveness of the proposed MPPT scheme is demonstrated under internal and external disturbances.

Control of Proton Exchange Membrane Fuel Cell (PEMFC) power system using PI controller

The Proton Exchange Membrane Fuel Cell (PEMFC) is one of the most important power supplies. Maintaining a constant voltage in PEM fuel cells with the presence of inputs and load variations, has always attracted the attention of many researchers and many articles have been published on this issue. This paper presents modeling of a PEM fuel cell connected to DC/DC boost converter. Subsequently, proportional integral controller (PI controller) is proposed to fix the fuel cell current. The model and the controller are implemented in the MATLAB and SIMULINK environment. Experiments were carried out using the fuel cell system PEM-Constructor of 50W (Heliocentris) and results are discussed.

PEM fuel cell green energy generation — SMC efficiency optimization

This paper presents a robust Sliding Mode Controller (SMC) for Proton Exchange Membrane Fuel Cell (PEMFC). The aim of this work is to keep the PEMFC working at its maximum operating power point in presence of inputs and load variations. However, due to the low output voltage of the PEMFC, DC/DC boost converter is used to obtain regulated high voltage DC. Therefore, the SMC is proposed to fix the fuel cell current by driving the boost converter connected between the fuel cell and the load. Stability of the closed loop system is analytically proved. The proposed SMC is validated by simulation studies in MATLAB/Simulink and results are discussed. Fast dynamic system response and robustness against load and input voltage variations are obtained.

A PV water desalination system using backstepping approach

This This paper involves a nonlinear control of photovoltaic system under changeable environmental conditions such as temperature and solar irradiance. The PV system (water desalination system) consists of the photovoltaic source which is feeding a resistor load (evaporator). The evaporator connected to a condenser. The control objective is to extract the maximum power from the PV generator by acting on the DC/DC converter (MPPT). The whole system is modulated and controlled by using the backstepping approach and tools from Lyapunov stability. The simulation results have been performed through Matlab/Simulink environment and show that the designed controller meets its objective.

Sliding Mode Real-Time Control of Photovoltaic Systems Using Neural Estimators

The maximum power point tracking (MPPT) problem has attracted the attention of many researchers, because it is convenient to obtain the maximum power of a photovoltaic module regardless of the weather conditions and the load. In this paper, a novel control for a boost DC/DC converter has been introduced. It is based on a sliding mode controller (SMC) that takes a current signal as reference instead of a voltage, which is generated by a neuronal reference current generator. That reference current indicates the current ( ) at the maximum power point (MPP) for given weather conditions. In order to test the designed control system, a photovoltaic module model based on a second artificial neuronal network (ANN) has been obtained from experimental data gathered during 18 months in the Faculty of Engineering Vitoria-Gasteiz (Spain). We have analyzed the performance of such model and we found that it is very accurate (MSE = 0.062 A and = 0.991 with test dataset). We also have tested the performance of the overall SMC design with both simulated and real tests, concluding that it guarantees that the power in the output of the converter is very close to the power of the photovoltaic module output.

Efficiency boosting for PV systems using new MPPT method

In this paper a PV system topology incorporating a new maximum power point tracking controller (MPPT) method using a PI controller is studied. The controller is formulated based on the bijectivity between the Voltage and Power in the PV generator (PVG) characteristic; therefore if the optimal voltage is reached, this means that the maximum of power is obtained. The proposed MPPT algorithm is implemented on a dSpace DS1104 controller board. In order to demonstrate the efficiency of the proposed algorithm in real time, an experimental setup using a boost converter connected to a resistive load is successfully implemented and studied. The obtained experimental results prove the validity of the proposed MPPT algorithm.

A robust MPP tracker based on backstepping algorithm for Proton Exchange Membrane Fuel Cell power system

This paper presents a comparision between two controllers for Proton Exchange Membrane Fuel Cell PEMFC power system. The aim of this work is to keep the PEMFC working at its MPP by acting on the DC/DC converter, and ensure an adequate robustness against load and inputs variations. Conventional controller PI and backstepping technique are applied to the DC/DC boost converter. The stability of the backstepping is demonstrated by means of Lyapunov analysis. The model and the controllers are implemented in the MATLAB and SIMULINK environment. Simulation results indicate that the aim of this work is achieved using the backstepping algorithm.

Smart auto-tuned regulators in electric vehicule PMSM drives

Proton Exchange Membrane fuel cell (PEMFC) is hybridized to share the current in a Hybrid Electrical Vehicle (HEV) power demand. The performance of the PEMFC model is analyzed for various loads connected nearer to the permanent magnet synchronous machine (PMSM), this latter is used to drive the air-compressor of a 6 kW fuel cell (EC) which will be beneficial for Electric Vehicle (EV) application. In order to obtain an efficient control for PMSM, particle swarm optimization (PSO) is used to optimise the parameters of the PI controller. The PEMFC model and the proposed algorithm is validated by simulation studies in MATLAB/Simulink environment and results are discussed.

Sensorless and robust PEMFEC power system drive based on Z(Tn)observability

In this paper, a robust Sliding Mode Controller (SMC) is applied to Proton Exchange Membrane Fuel Cell power system (PEMFC) to keep this latter working at its maximum operating power point, DC/DC interleved boost converter (IBC) is used in conjunction with the fuel cell generator for obtaining an efficient conversion from the PEMFC stack to the load. In order to minimize the number of sensors, a hybrid observer is applied to the IBC for reconstructing the system parameters values. However this particular switched system induces a difficult observability problems, such problem can be solved by a new observability concept called Z(TN)-observability. The proposed hybrid observer is based on a homogeneous observer coupled with an estimator. The performance of the proposed SMC and hybrid observer are validated by simulation studies in MATLAB/Simulink and results are discussed.