A novel approach to the DSP-based control of photovoltaic (PV) energy storage systems for distributed PV module is presented. A DSP is used to implement the power feedback control, maximum power point tracking (MPPT) and unfalsified control for the PV system. A MPPT control with duty ratio versus PV module output power has been developed. The major difference between the proposed MPPT control and other methods is that the PV module output power is used to adjust the ratio of power converter. The proposed system has excellent tracking performance and high conversion efficiency. In this paper, parameter tuning and adaptation of real-time PI controller is accomplished based on unfalsified control theory. A plant model is not necessary with the proposed control law, and the selection of PI gain is possible by using measured data. Simulations and experimental results demonstrate excellent performance and robustness under atmospheric variations.