A photovoltaic (PV) module simulator was developed based on an equivalent circuit with one-diode, taking into account variations of the solar irradiation and the temperature. The parameter estimation was carried out using the datasheet values provided by manufacturers and by solving a system of equations established from the physics of solar cells that constitute the photovoltaic module. The simulator was programmed using SPICE and Matlab/Simulink, for generating the I–V and P-V output curves of typical PV modules at different operating conditions. With these tools we can simulate the behavior of PV systems under real operating conditions, and we can also develop and test maximum power tracking algorithms for any PV module.