In this paper, the design of a fuzzy rule-based MDPSM controlled buck converter is analyzed. Power factor improvement and harmonic minimization for the buck converter connected through the variable load with a fuzzy rule are discussed and simulated. The MDPSM controlled converter is supplied with 230[Formula: see text]V and reaches 15[Formula: see text]V as output. The converter output, always connected with nonlinear loads, causes less power factor with more harmonics and gives less power quality. Active PFC with a fuzzy-based voltage controlled power factor controller is designed to reduce total harmonics and to raise the power factor value equal to unity. The fuzzy-based MDPSM controller was designed using MATLAB Simulink. Controller output waveforms are examined and analyzed with other controller performances. The converter is rated with 2[Formula: see text]mA, 0.5[Formula: see text]mH and 212[Formula: see text][Formula: see text]F values with output power 48[Formula: see text]W. The converter is tested for different resistive loads and inductive loads.