Abstract: A photovoltaic power estimation model accurate to the minute is proposed, which is suitable for fixed and dual-axis tracking PV arrays. Firstly,according to the sun position,the measured horizontal beam radiation,diffuse radiation,and the mounting structure,the total radiation absorbed by the PV array is calculated. Secondly,the output power is estimated based on the radiation and the efficiency of PV modules and inverters. The incidence angle modifier,the loss induced by degradation and dirt and the correction of DNI are considered in the model. The model is validated using the data of the desert knowledge Australia solar center（DKASC）. The model is applied to research the energy yield gain of dual-axis tracking array relative to fixed array.