Digital controller for a boost PFC converter in continuous conduction mode

This paper introduces a design process for a R-S-T digital controller for a power factor correction circuit (PFC). This method is based on pole placement via R-S-T polynomials. The design is based on the desired time domain specification of the current and voltage loops of a PFC presented as a discretized second order s domain transfer function for voltage and current loops. The voltage and current loop polynimials are designed to achieve the same behavior as in the s domain. Overall performance of both digital controller and its analog counterpart for PFC are investigated based on the effect of a step variation in output current, step variation and tracking of the reference voltage, and the quality of the reference current and its tracking. Furthermore, errors in the parameters identification are also taken into consideration to test the robustness of both controllers. The results confirm that digital R-S-T based controllers are able to be used for high performance PFC converters.