Buck Converter Digital Control System Design and Performance Evaluation

Abstract

Most of modern converters are controlled in discrete time domain with digital converter. Therefore, accurate enough plant model is required for a design of the digital control system. A paper contains common approach on digital voltage mode PI controller design for calculated plant model. In comparison to boost, the buck converter has no RHP and performs with high linearity in CCM, the real converter may have differences. A low gain perturbance at different frequencies may be introduced to a PWM controller to measure gain and phase reaction on a small-signal change to get a Bode-plot of a plant. Estimated and calculated plants are compared and analyzed to achieve better performance in real device.