Buck DC DC converter using fuzzy logic control for no linear load

Abstract

Background: This paper presents a mathematical system called fuzzy logic as a control technique to improve the performance of a DC-DC converter (Buck) to changes in non-linear loads. Method: Through Simulink MATLAB was built a DC-DC converter of closed loop, which is placed in series with a controller based on fuzzy logic. The control inputs are the voltage signal and its derivati­ve, and the output is a constant value, which tunes the duty cycle of a pulse modulator (PWM). This ad­just the output of voltage of the controller according to a desired reference. The fuzzy controller was built with membership functions in which linguistic varia­bles that explain when a value of output of voltage must be corrected and when the voltage variation is out of the established ranges between -1 and 1 per­cent of allowable variation were integrated. Results: To evaluate the performance of this type of control compared to a DC-DC converter with control of closed loop of unity gain, obtaining a 40% impro­vement in the integral of area regarding the fuzzy con­troller, with a stabilization time of 0.01s. In non-linear loads, there are random phenomena or own unwan­ted effects of resonance circuit, then was emulated by interrupting cycles of a time-controlled switch.

Keywords

• carga no lineal, convertidor Buck, ciclo útil, funciones de pertenencia, lógica difusa,