Abstract:

Aiming at LLC resonant converter controlled by frequency conversion,a circuit parameter optimization design method based on impedance vector algorithm is proposed.Firstly,the mathematical model of HB-LLC converter gain is basically derived;Secondly,the resonator input impedance model based on the boundary conditions is built.Moreover,the vector diagram for gain inverse transfer function is created and the mathematical expressions for resonator parameters are derived,and the minimum switching frequency can be calculated based on the design goal of minimum value of energy function.Finally,based on the mathematical calculation of MATHCAD and the simulation model of Simplis,as well as the actual experimental test results,the validity of proposed optimization methods is verified,which can provide a novel and simple solution for LLC converter optimized design and engineering product.

Key words: LLC converter, gain inverse, vector algorithm, minimum switching frequency