Become a Member
Become a Member


A Gain-based 2.2kW Totem-pole PFC Rectifier for Electric Vehicle Applications

totem-pole PFC
Fig. 1. 2-phase interleaved totem-pole PFC.
  Totem-pole PFC is well known as the simplest topology among bridgeless boost PFC structures. With the emergence of high-voltage Gallium-Nitride (GaN) high- electron-mobility transistor (HEMT), totem-pole structure is becoming increasingly popular for PFC rectifier. GaN HEMT has comparatively high turn-on loss and extremely small turn-off loss, which makes CRM soft switching operation very suitable to reduce switching loss by achieving zero-voltage switch (ZVS) during turn-on process. Two-phase interleaving is implemented to reduce DM noise and balance technique is introduced to this system to reduce CM noise. By pushing to high switching frequency, boost inductor value can be reduced, and together with balance technique, the boost inductor can be integrated to PCB winding inductor. The system is shown in Fig. 1. A double loop control strategy is proposed to control this totem-pole PFC system, as shown in Fig. 2. Inner average current loop controls the average current to track the desired sinusoidal reference. The Toff calculation based on Iref, Vin and Vo guarantees the system works in CRM to achieve ZVS. Also, Ton is extended at line voltage zero-crossing area by the average current loop to improve the THD performance. Open-loop interleaving control is implemented to control the phase shift between the leading phase and following phase. The output voltage loop controls the output voltage. All control functions are implemented in a single digital signal processor.
Control strategy
Fig. 2. Control strategy of 2-phase interleaved totem-pole PFC

Our Industry Partners