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Analysis on Closed Loop Control for GaN-Based CRM Totem-Pole PFC
Year: 2023 | Author: Xingyu Chen | Paper: H5.4
Fig 1: 2.2kW two-phase interleaving GaN-based CRM totem-pole PFC prototype.
In this paper, a microcontroller-based control method for the GaN-based critical conduction mode (CRM) totem-pole PFC is proposed. A simple digital control method based on a synchronous rectifier (SR) on-time calculation -- which ensures zero-voltage switching (ZVS) without zero-current detection (ZCD) -- is proposed. Average current-mode control is discussed and a compensator gain adjustment method is introduced to improve PF and restrain THD. Finally, all control functions are integrated into a microcontroller unit (MCU) and demonstrated on a 2.2kW GaN-based two-phase interleaved CRM totem-pole PFC prototype, as shown in Fig. 1. Fig. 2 shows the control diagram. Also, the proposed control strategy is compared to the traditional ZCD-based control.
The prototype with proposed control method can reach a peak efficiency of 98.96% and full-load efficiency of 98.55%. The converter reaches a PF of 0.996 at full load.
