Pulse Phase Shift Based Low-Frequency Oscillation Suppression for PT Controlled CCM Buck Converter

Pulse train (PT) control has the advantages of simple structure, fast transient response, low cost, and free compensation network. However, for the power converters operated in continuous conduction mode, undesired low-frequency oscillation of output voltage will be brought about by PT control. To resolve this issue, the pulse phase shift based PT (PPS-PT) control method is newly proposed in this brief and applied in the buck converter. The approximate discrete time model of PPS-PT controlled buck converter is established, and the bifurcation diagrams of output voltage altering along with the difference of inductor current boundaries and load resistance are drawn to show the operation characteristics of the converter. Simulation and experimental results indicate that the proposed PPS-PT method can provide attractive control performance with the advantages of very simple implementation, small output voltage ripple, and wide load range.