Digital-Based Interleaving Control for GaN-based MHz CRM Totem-pole PFC

摘要

In this paper, the performance of differentrninterleaving control methods for gallium-nitride (GaN) devicesrnbased MHz critical conduction mode (CRM) totem-pole powerrnfactor correction (PFC) circuit is compared. Both closed-looprninterleaving and open-loop interleaving are good for lowrnfrequency CRM PFC; but for MHz very high frequency CRMrnPFC with microcontroller (MCU) implementation, open-looprninterleaving outperforms closed-loop interleaving with small andrnnon-amplified phase error. After software optimization, thernphase error of open-loop interleaving is smaller than 3 degree atrn1MHz, when the control is implemented by 60MHz low costrnMCU. Significant ripple cancellation effect and differential-modern(DM) filter size reduction is achieved with good interleaving. Forrna 1.2kW MHz totem-pole PFC, the DM filter size is reduced tornone quarter compared to the counterpart of a 100kHz PFC. Lastrnbut not least, the stability of open-loop interleaving is alsornanalyzed indicating that the MHz CRM totem-pole PFC withrnvoltage-mode control, open-loop interleaving, and turn-on instantrnsynchronization can maintain critical mode operation with betterrnstability compared to low frequency CRM PFC.