Effects of Adding the Antiparallel Diodes in a Model of Solar Photovoltaic Cell: Theory and Pspice Simulations

Abstract

Background: The photovoltaic (PV) array consisting of modules is considered as the fundamental electrical power conversion unit of the PV generator system. The PV array has nonlinear characteristics with the current-voltage (I-V) characteristic in the exponential form introduced by diodes. In this context, the key objective of the research carried out in the present study is to propose a novel PV cell, with anti-parallel diodes introduced in the circuit model in place of the single diode. Objective: The objective of this research is to compare the effects, magnitudes of current and power generated by the PV cell, with antiparallel diodes to those with single diodes. Methods: The model circuit containing two antiparallel diodes is first designed, and then analyzed through the circuit Equationuations found using the Kirchhoff’s laws. The I-V characteristics are modified in the hyperbolic sine form, and the model Equationuation is solved analytically and numerically using the MATLAB software. The analytical and numerical investigations are then confirmed by Pspice simulation, which is made possible with the introduction of additional bloc necessary to make the output signal voltage tunable in the opened circuit. Results: The I-V characteristic is plotted showing that when the voltage is lower than a particular, the model containing the antiparallel diode has the increasing of current, while that with single diode has constant current. Additionally the current generated by the PV cell oscillates increasingly when the supplied signal voltage is negative. We also found that the maximum power increases with the temperature. The expression of the cutoff signal voltage leading to zero current was also found and plotted, the increasing function of the number Ns of series diodes. As application, the PV circuit designed is used in the charging of the battery of electrical vehicle. Conclusion: The PV cell with antiparallel diodes generates currents for large band of signal voltage, and the power generated increases with temperature.