Modeling and implementation of digital control for critical conduction mode power factor correction rectifier

Digital control design for critical conduction mode (CRM) power factor correction (PFC) rectifier is presented in this paper. As its software, conventional analog design method for CRM is modified and applied to the digital control loop. As its hardware, a control circuit is practically implemented in conjunction with a microcontroller for additional functionalities such as zero current detection and maximum frequency limit. A 250-W prototype boost rectifier is built and experimented to verify the performance of the proposed control design.