Simulating photovoltaic (PV) power systems becomes important when studying integration issues of the intermittent solar energy into electric grids. The accuracy of the maximum power point (MPP) in PV output model is a concern since it represents the capacity of power generation. This paper proposes a comprehensive approach to identify PV cell parameters and avoid model errors of the MPP based on standard and simplified equivalent circuits. The estimation accuracy has been improved while maintaining the computational simplicity. This paper begins with the definition of the performance index used to quantify the model accuracy at the MPP. Based on the availability of information from the manufacturer’s datasheets, the accuracy and complexity of different equivalent circuits are discussed and investigated. The proposed approach has been successfully tested for solar cells made of mono and multi crystalline material.