Phase compensation, ZVS operation of wireless power transfer system based on SOGI-PLL

Wireless power transfer (WPT) technology is now recognized as an efficient means of transferring power because having numerous advantages over conventional wired power transfer system. The phase delays, for example induced in the sampling process, the algorithm implementation process, the signal transduction process, etc. are widely found during the implementation of WPT system, which significantly degrade the system performance. Moreover, it would be extremely necessary to implement the Soft-Switching of the converter and the necessary dead time imposed by the drivers should be compatible with the resonant current phase lag control. This paper proposes a Direct Phase Control (DPC) approach, based on Second-Order Generalized Integrator Phase-Locked Loop (SOGI-PLL), to provide accurate phase compensation and stable ZVS operation in the WPT. The DPC determines the phase difference Δθ of WPT, which include the phase difference θι between the output voltage and current of the converter and the phase delay θ"ι derived from the sampling process. The SOGI-PLL provides the phase of system for adjusting the output voltage frequency of the converter dynamically. Experimental results convincingly demonstrate that with the proposed method the phase delay can be compensated accurately and the ZVS operation can be achieved simultaneously.