Frequency and Phase Synchronous Control Method Without Communication of the BCPT System

Bidirectional capacitive power transfer (BCPT) systems provide a flexible and economical method for energy interaction and sharing among multiple electronic devices. BCPT systems utilize two independent controllers for the primary and secondary converters. Out of synchronization between two converters will cause power oscillation and the actual power cannot be guaranteed. This article proposes a synchronous control method of the dual
LCLC
-compensated BCPT system without wireless communication. The method utilizes two pairs of supplementary plates to form the composite plate coupler and then derives a four-port equivalent circuit model from the coupling capacitance model. The induced voltage of secondary supplementary plates is synchronized with the resonant voltage generated by the primary converter so as to obtain the frequency and phase of the primary main plates and feed it back to the secondary controller. Due to the interoperability of the proposed system, the primary supplementary plates can also obtain the synchronization status of the secondary converter and provide feedback to the primary controller. Besides, there is no need for complex data processing analyses of the proposed synchronization control method, which is favorable to operate in a high-frequency BCPT system. The experimental results validate the effectiveness of the proposed synchronous control method in the BCPT systems.