Parameters Design of LLC DC converter Based on Peak Gain Point Distribution

The peak gain point of LLC DC converter is the starting point for the main switch to achieve zero-voltage switching, and the peak gain reflects its capability in voltage regulation. The peak gain point of PON mode has a higher gain than that of PN mode. However, there is no analytical solution for the gain characteristics in this mode, so it is difficult to locate the peak gain point, which brings a certain challenge to employ the advantage of peak gain and design parameters of resonant tank. This paper presents a simple, efficient, and high-precision design method. Firstly, the peak gain point of gain is accurately located, then the range of inductance ratio is limited according to the peak gain point distribution and the maximum gain requirement, and the optimal matching between inductance ratio and normalized power is determined according to the principle of minimum cycle power. Based on this, the parameters are designed to obtain accurate peak value gain and PLECS simulation results verify the correctness and effectiveness of the proposed method.