Control of oscillations in PFC power supplies by Time Delay Feedback

In this paper, Time Delay Feedback Control (TDFC) is applied to stabilize a two-stage Power factor converter when it exhibits instabilities at the line period under traditional controllers. The TDFC introduces many advantages to the most and widely used Average Current Mode (ACM) control through widening the stability domain of the PFC converter. A Harmonic Balance (HB) approach is used for studying the dynamics of the system under the new scheme of control and to obtain the stabilization domain. By appropriately selecting the time delay feedback gain and the time delay period, the system can be stabilized.