Digital control implementation to reduce the cost and improve the performance of the control stage of an industrial switch-mode power supply

Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. D. A. Díez, O. M. García, J. A. Oliver, P. Alou, F. Moreno, B. Duret, J. A. Cobos, F. V. Canales, and A. de Castro, "Digital control implementation to reduce the cost and improve the performance of the control stage of an industrial switch-mode power supply", in 2011 IEEE Energy Conversion Congress and Exposition (ECCE), Phoenix (AZ), 2011, pp. 2930 - 2935The main objective of this work is the design and implementation of the digital control stage of a 280W AC/DC industrial power supply in a single low-cost microcontroller to replace the analog control stage. The switch-mode power supply (SMPS) consists of a PFC boost converter with fixed frequency operation and a variable frequency LLC series resonant DC/DC converter. Input voltage range is 85VRMS-550VRMS and the output voltage range is 24V-28V. A digital controller is especially suitable for this kind of SMPS to implement its multiple functionalities and to keep the efficiency and the performance high over the wide range of input voltages. Additional advantages of the digital control are reliability and size. The optimized design and implementation of the digital control stage it is presented. Experimental results show the stable operation of the controlled system and an estimation of the cost reduction achieved with the digital control stage