Single and Multi-Phase Synchronous Buck Converter Voltage Control with Modeling, PID Controller Design, and Digital Implementation

Abstract

This paper covers the modeling and design of a digital controller for a single and multi-phase synchronous buck converter. First, a general overview of the power switching point-of-load (POL) converters will be presented. This will be accompanied by a general overview of a digital system which explains the differences between discrete and continuous timed domains. This system overview will look at the primary components of a digital system which includes the plant, sampler, reconstruction block as well as the control system block. With a general idea of a discrete timed system, a plant model must be developed. This model is constructed from a single synchronous buck converter's circuit schematic. From this, the equations defining the converter are solved and converted into a block diagram. This block diagram is used to develop a discrete and continuous timed PID controller for the system using Matlab's Simulink. This single phase simulation is expanded to higher phase counts. Finally this digital controller is implemented on hardware. The controlling algorithm is programmed into a microcontroller and tested on single and multi-phase converters.