A PT Controlled Buck Converter with Coupled Inductors

In order to minimize the output low-frequency oscillation of pulse train (PT) controlled buck converters operated in continuous current mode (CCM), a modified Buck converter by using coupled inductors is newly proposed in this paper. The discrete-time model and the low-frequency oscillation mechanism of this new converter are analyzed in details, and the corresponding solution method was given for this problem. The bifurcation diagrams of the output voltage and the switching peak current in terms of variable coupling coefficients of two coupled inductors are obtained, and the influence of the coupling coefficients on the low-frequency oscillation is reported based on the bifurcation diagrams. Finally, the simulation results are provided to verify the correctness of the theoretical analysis. The theoretical analysis and simulation results show that by configuring an appropriate value of the coupled coefficient, the output voltage can be adjusted in time by PT control and the low-frequency oscillation can be thus eventually eliminated.