Digital Control Of A Buck Converter Using An 8 Bit STM Microcontroller

The aim of this paper is to describe the modeling and digital control of a buck converter using an 8 bit STM microcontroller. The modeling procedure including the inductor dc resistance and capacitor esr using both the circuit averaging as well as the state space averaging method is described in a simple manner. The resulting small signal control to output transfer function is used to select a suitable PID controller in order to obtain satisfactory control loop performance and also maintain ease of implementation. Practical issues involved in implementing digital control using 8 bit microcontrollers are discussed. MATLB Simulations and practical implementation results on a STM8S controller are presented to validate the modeling and controller design approach. The perspective applications of this controller are discussed.