Staggered parallel Buck converter sliding mode control method and system

The embodiment of the invention provides a sliding mode control method and system for an interleaved Buck converter, and the method comprises the steps: building an average state model of the interleaved Buck converter based on a topological structure of the interleaved Buck converter; generating a corresponding reduced-order linear expansion state observer for the average state model of the interleaved Buck converter, wherein the reduced-order linear expansion state observer is used for observing matching interference and non-matching interference of the topological structure; the nonsingular terminal sliding mode controller receives interference detected by the reduced-order linear expansion state observer, generates a reference value of inductive current in an inner ring and transmits the reference value to the PI controller, so that the PI controller controls current phases in the topological structure, and the total number of the current phases is equal to the phase number of the interleaved parallel Buc