The study on fixed-frequency sliding mode control method of DC/DC converter

The sliding variable structural control method has been used in DC/DC converter widely and show the excellent dynamic performance and the strong robustness, but the conventional sliding mode control, which control rule is sign function, has some shortcomings, for which switching frequency is uncertain and control result is serious influenced by the sliding surface parameter and the circuit parastic. In this paper, a novel fixed-frequency sliding mode control is proposed for control rule changed with duty cycle. The proposed method can make system working at a fixed frequency, has the same good dynamic characteristics with the traditional sliding control, and is easy to realize with digital circuit after analysis. The correctness and validity of proposed control algorithm are proved by simulation and experiment results.