Sliding mode control method and system of resonant converter based on nonlinear disturbance observer

The invention belongs to the technical field of power electronic DC/DC converter control, and discloses a sliding mode control method and system for a resonant converter based on a nonlinear disturbance observer, and the method comprises the steps: obtaining the rectified current of a secondary side and the capacitor voltage of an output end; establishing a state-space equation of the LLC resonant converter required for designing the sliding-mode control and disturbance observer by using the sampled current and voltage values and known circuit element parameters; aiming at the system model, designing a sliding mode surface of sliding mode control based on a sliding mode control theory, and designing a control law based on the sliding mode surface; a nonlinear disturbance observer is designed to be combined with sliding mode control to optimize the control effect; and performing inverse transformation on the control law basis to obtain a value of actual control quantity switching frequency, taking the value as