In this paper, a simplified single-diode model for photovoltaic (PV) modules is presented. Improved current and voltage translation equations were also deduced. Combined with conventional and improved translation equations respectively, the accuracy of two models was analyzed. Experimental results showed that two models both reveal good conformance with outdoor measured current-voltage (I-V) curves. And improved translation equations can make the simplified model more accurate under low irradiance levels. Data sheet provided by manufactures and the outdoor measured reference data were respectively utilized to calculate model parameters for comparison. Comparison results showed that manufacture's data sheet would cause higher deviation for proposed models. Finally, the simplified model combined with improved translation equations is recommended. This model can be programmed conveniently in MATLAB. Corresponding PV module block was also designed in Simulink and detail building procedures of the block was introduced. (C) 2013 Elsevier Ltd. All rights reserved.