Currently, many stand-alone microgrids are operated based on diesel generators. However, due to economic and environmental issues, it is imperative to enhance the utilization of renewable energy sources such as photovoltaic(PV) and wind turbine(WT). Nevertheless, renewable energy sources have intermittent characteristics, which can lead to problems such as reverse flow, voltage fluctuations, and exceeding current limits. In general, energy storage systems(ESS) can solve these issues. This paper presents a power sharing control algorithm between diesel generator and ESS to control the net load variation in stand-alone microgrids. The proposed method dynamically adjusts the power sharing ratio based on the magnitude and sign of net load variation and the state of charge(SOC) of the ESS. This allows the SOC of the ESS to be maintained within the allowable range, enabling the proper sharing of power output between the diesel generator and the ESS. The effectiveness of the proposed approach is verified through various simulation scenarios utilizing a MATLAB/Simulink model.