This paper proposes a comprehensive MATLAB Simulink simulator for photovoltaic (PV) system. The simulator utilizes a new two-diode model to represent the PV cell. This model is known to have better accuracy at low irradiance level that allows for a more accurate prediction of PV system performance during partial shading condition. To reduce computational time, only four parameters are extracted for the model. The values of R(p) and R(s) are computed by an efficient iteration method. Furthermore, all the inputs to the simulators are information available on standard PV module datasheet. The simulator supports a large array combination that can be interfaced to MPPT algorithms and power electronic converters. The accurateness of the simulator is verified by applying the model to five PV modules of different types (multi-crystalline, mono-crystalline, and thin-film) from various manufacturers. It is envisaged that the proposed work can be very useful for PV professionals who require simple, fast, and accurate PV simulator to design their systems. The developed simulator is freely available for download. (C) 2011 Elsevier Ltd. All rights reserved.