Analysis and Controller Design for Positive Output Boost Converter with Low Current Stress on Output Capacitor

A non-isolated type positive output fifth-order dc-dc boost converter is proposed in this paper. This topology is developed from the existing fourth-order boost converter (FOBC) by appropriately inserting a charge-pump cell. Compared to FOBC, the proposed topology offers enhanced voltage gain with reduced switch voltage stress. The proposed converter has an advantage of continuous output-port current over existing boost topologies, which reduces the output capacitor current stress. The voltage conversion ratio and LC design equations in terms of their ripple quantities are formulated by time-domain analysis. Thereafter, a summary of comparison between the proposed converter and existing boost topologies is presented. The small-signal duty-to-output voltage transfer function obtained through the average state-space model shows minimum phase behavior. A PID type voltage-mode controller is designed using the dominant pole placement technique to ensure predefined time-domain specifications along with sufficient dominance factor (DF). Maximum sensitivity (Ms) is adopted as a measure to ensure the required robustness of the closed-loop system. The analysis and voltage-mode controller design are verified through experimental results. The dynamic performance and robustness of the closed-loop system tested experimentally are in agreement with the desired requirements.