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The Maximum Power Point Tracker (MPPT) is the optimum operating point of a photovoltaic module. It plays a very important role to obtain the maximum power of a solar panel as it allows an optimal use of a photovoltaic system, regardless of irradiation and temperature variations. In this research, we present a novel technique to improve the control’s performances optimization of the system consisting of a photovoltaic panel, a buck converter and a load. Simulations of different parts of the system are developed under Matlab/Simulink, thus allowing a comparison between the performances of the three studied controllers: “Fuzzy TS”, “P&O” and “PSO”. The three algorithms of MPPT associated with these techniques are tested in different meteorological conditions. The obtained results, in different operating conditions, reveal a clear improvement of controlling performances of MPPT of a photovoltaic system when the PSO tracking technique is used.

The photovoltaic solar energy deriving from the direct transformation of a part of solar irradiation into electric energy faces, inter alia, a maximization problem of power transfer of the photovoltaic generator (PVG) to the load. This is due to the non-linear feature of the electric characteristics I-V (Current-Voltage) of photovoltaic cells [

In this work, we present a robust technique which permits to track the MMP of the PV panel system, thanks to the controller using PSO. This control technique reduces the calculating time and keeps a good precision. In addition, it can be implemented in a low-cost microcontroller [

This paper is organized as follows. We present, in Section 2, the working environment and the electric modelling of the studied system, as well as the description of the developed algorithms for tracking techniques of MPP: “P&O”, “Fuzzy TS” and “PSO”. Section 3 is dedicated to the presentation of models under Matlab/Simulink version 2014 associated with different components of the tested conversion chain. In Section 4, we show and interpret simulation’s results concerning the PV system behaviors under the effect of one of the three controllers “P&O”, “Fuzzy TS” or “PSO” under different irradiation changes S and temperature T. We present also the evaluation of the performances of each of the studied MPP controllers. Finally, we finish our contribution with a summary of our research works.

As the PV conversion chain illustrates in

The studied PV panel (^{2}, 25˚C and AM 1.5. We will present the Matlab-Simulink model which is based on these characteristic values.

In order to model our PV panel, we start with a simple model which is one of a PV elementary cell. The configuration that _{pv}, connected in parallel with a diode D, characterizing the junction of semi-conductors which make the solar cell, and a parallel resistance R_{p}. To this assembly, another resistance R_{s} is added in series.

The model of a PVG issues from this schema, defined by the following equations [

With:

- a: Ideality factor of the solar cell.

- ΔT = T − T_{n} (Kelvin), T: Real temperature of the cells and T_{n}: nominal temperature of the cells in the Standard Test Conditions (STC): 1000 W/m^{2}, 25˚C and AM 1.5.

Parameters | Values |
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Pmax: maximum power | 150 W |

Imp: maximum power current | 4.35 A |

Vmp: maximum power voltage | 34.5 V |

Ns: number of series cells | 36 |

Isc: short circuit current | 4.75 A |

Voc: open circuit voltage | 43.5 V |

- S: Real Irradiation (W/m^{2}).

- S_{n}: Nominal Irradiation in the Standard Test Conditions (W/m^{2}).

- I_{0}: Diode reverse saturation current (A).

- I_{pv}_{,n}: Current measured under Standard Test Conditions (A).

- I, V: PVG current (A) and voltage (V).

- I_{sc}_{,n} and V_{oc}_{,n}: Short circuit current (A) and Open circuit voltage (V) measured under Standard Test Conditions.

- V_{t} = N_{s}KT/q: Thermal voltage.

- N_{s}: Number of series-connected cells.

- K: Boltzmann constant (1.38 10 - 23 J/K).

- K_{v}: temperature coefficient of the open circuit voltage(=80 ± 10 mV/˚C).

- K_{i}: temperature coefficient of the short circuit current (=0.065 ± 0.015) %/˚C.

- q: Electron charge (1.6 10 - 19 C).

- R_{s}, R_{p}: Series resistance (=0.2365 Ω) and parallel resistance (=415.405 Ω) respectively.

In our research, the suggested system in

As far as the simulations of the studied converter are concerned, the parameters we have used are: the resistance of the load being R_{c} = 3 Ω, the capacitance of the capacitor being C = 4.7 μF, the inductance of the inductor being L = 2 mH, D being freewheeling diode and T being a transistor type MOSFET. During the operation in continuous mode of this buck converter, the average values of the output voltage V_{s} and input voltage V_{e} are proportional as follows: