Dynamic modeling and integral sliding mode controller design for Cuk converter under load variation

A integral sliding mode controller (ISMC) for a fixed-frequency PWM is proposed for the Cuk converter. The fourth-order model of the Cuk converter is derived first and it is simplified to use ISMC. Based on the simplified system model, the ISMC that consists of the equivalent control part plus the switching control part is designed and applied to the Cuk converter in the presence of uncertain variations and unknown disturbances. The closed-loop system is also proved to be exponentially stable. Simulation and experimental tests using the prototype of digitally controlled DC-DC converter were performed to validate the proposed control approach.