A Voltage-fed Control Method with Automatic Bidirectional Power Switching Capability for CLLC and SR Buck Based Two Stage Converters

The CLLC converter is widely used in bidirectional power conversion systems. The conventional control method for CLLC converter is pulse frequency modulation (PFM) method. However, PFM method can not realize smooth bidirectional power switching, because the driver signals for the primary and the secondary side switches are asymmetric. This paper proposed a voltage-fed control method for CLLC and Synchronous Rectified (SR) Buck two stage converters, which can realize the automatic and smooth bidirectional power switching for CLLC stage. In the proposed control method, the PWM signals for both the primary and the secondary switches are the same. The effectiveness of the proposed voltage-fed control method is verified by experiments.