Fuzzy logic driven adaptive PID controller for PWM based buck converter

This paper presents the design and construction of a fuzzy logic based proportional integral derivative (PID) controller for the control of a pulse width modulation (PWM)based dc-dc buck converter working in Continuous Conduction Mode(CCM). The converter operates at a switching frequency of 100 KHz. Computer simulation is done to fuzzify the inputs and their membership functions, express the inference rules linking the input and output variables and defuzzify the output parameter. This approach is simple as no linearized model of the buck converter is required. In the simulation results it is seen that the fuzzy logic based PID control technique provides robust control for non-linear power electronics variable switching structure like the ideal dc-dc buck converter. The practical model of the buck converter is next considered. From extensive experimentations for various parameter set and load disturbances, it is shown that the proposed adaptive Fuzzy logic driven PID controlled buck converter outperforms such non-adaptive PID controlled converters in terms of rise time, settling time and ripple voltage at the output response.