IMPLEMENTATION OF A FUZZY CONTROLLER FOR DC-DC CONVERTERS USING AN INEXPENSIVE 8-B MICROCONTROLLER

This paper presents an implementation of a fuzzy controller for dc-dc converters using an inexpensive 8-b microcontroller. An ''on-chip'' an alog-to-digital (A/D) converter and PWM generator eliminate the extern al components needed to perform these functions, Implementation issues include limited on-chip program memory of 2 kB, unsigned integer arit hmetic, and computational delay, The duty cycle far the dc-dc converte r can only be updated every eight switching cycles because of the time required for the A/D conversion and the control calculations. However , it is demonstrated here that stable responses can be obtained for bo th buck and boost converters under these conditions, Another important result is that the same microcontroller code, without any modificatio ns, can control both converters because their behavior can be describe d by the same set of linguistic rules, The contribution shows that a n onlinear controller such as fuzzy logic can be inexpensively implement ed with microcontroller technology.