Design and Implementation of a Novel Hybrid Posicast Based Controller for a Buck-Boost Converter

Implementation of hybrid posicast-based control of buck-boost converter have been presented. Posicast is a feed-forward compensator to eliminate the overshoot in system behavior. Traditionally it is used as a feed-forward compensator which is sensitive to changes in natural frequency. Hence to avoid this in the conventional method, the posicast element is used within the feedback loop. Also conventionally the posicast technique is used for buck converter and boost converter. The proposed method uses the implementation of posicast technique to buck-boost converter. The posicast element is intended for the dc-dc buck-boost converter to overcome the sensitivity issue. Further the presence of RHP zeroes and other elements in the dc-dc buck-boost converter introduce undesirable effects on system stability. The posicast technique eliminates the sensitivity issue, overshoot problem and ensures steady state stability. The performance of posicast based control of buck-boost converter is compared with the ideal dynamics of the plant system and with the PID controller by simulation using MATLAB. Also the simulation result of posicast compensated system was compared with the experimental results.