An effective POS (Photovoltaic Output Sensorless) MPPT (Maximum Power Point Tracking) control method for PV (PhotoVoltaic) power generation system is proposed in this paper. A fuzzy logic based algorithm, which has a simple feedback structure and fewer measured parameters, is proposed and applied to the control strategy of a DC/DC converter for effective realization of MPPT (Maximum Power Point Tracking). The main advantages of this method are that the oscillation of power around at maximum power point and tracking time can be minimized, and the cost of overall system can be reduced as well. The effectiveness of proposed method is demonstrated through the simulation and experiment of a model PV power generation system. Index Terms--PV (PhotoVoltaic), MPPT (Maximum Power Point Tracking), POS (Photovoltaic Output Sensorless), FLC (Fuzzy Logic Control).