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

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, whose control rule is sign function, has some shortcomings, for which switching frequency is uncertain and control result is serious influenced by the sliding surface parameters and the circuit parasitic. 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 worked at a fixed frequency, having better dynamic characteristics than the traditional sliding control. It is easy to realize with digital circuit after analysis. The correctness and validity of proposed control algorithm are proved by simulation results.