LLC synchronous rectification control method based on sensorless detection

The invention provides a sensorless LLC synchronous rectification digital control method, and relates to the field of power electronics. The control method specifically comprises the following steps: establishing an LLC resonant converter control circuit without sensor control; establishing an LLC time domain mathematical model considering the parasitic inductance Ls; acquiring actual parameters of a resonant inductor Lr, a resonant capacitor Cr, an excitation inductor Lm and a parasitic inductor Ls in the LLC time domain mathematical model; on the basis of the time domain mathematical model, establishing an iterative solution model to obtain the turn-on moment and the turn-off moment of the synchronous tube; and establishing an LLC synchronous rectification starting, transient and steady state control method. High-precision synchronous rectification control can be completed without adding a hardware detection circuit, interference of parasitic parameters and switching noise is avoided, and high configuration