Optimal Design of Lossless Passive Snubber for DC/DC Converters

This paper presents an optimal design of lossless passive snubber for DC/DC converters, which offers an efficient and best design method. The proposed method can not only reduce the spike voltage V_dsp of a power switch in the circuit, but also raise the conversion efficiency of the converter. In this paper, we have used Taguchi method to create the optimal design of LC lossless snubber. It can overcome the chaotic drawback of trial-and-error method, the bias of one-factor-at-a-time experiments, and the disadvantage of too many trials for full-factorial experiments. In Taguchi method, the voltage V _ds of power switch and source side current I_in are the quality characteristics of the circuit, and the snubber inductor L _c, snubber capacitor C_L, transformer leakage inductor L_e, and switching frequency f are control factors which influence the circuit quality characteristics. According to the control factors and levels, this paper used an orthogonal array L₉ (3⁴) to implement experiments, and made a factor response table and graph. Eventually, the optimal values of the control factors L_c, C_L, L_e and f were decided and then increased ratio of S/N to 16.8%. The simulation results demonstrated that the proposed method applying to optimal design of LC lossless snubber circuit was feasible and efficient