Current fluctuation analysis of a quantum ac-ac resonant converter for contactless power transfer

A direct ac-ac converter based on quantum energy injection control has many good features such as low component count, low operation frequency for high frequency current generation, compared with traditional controllers. However, when ZCS operation is required, the output current shows obvious fluctuations during operation. It is necessary to qualify the current ripples and sags for practical applications. This paper reviews the basic ZCS operation of an ac-ac converter and gives a detailed fluctuation analysis of the output current generated. Both simulation and experimental studies are presented to verify the theoretical analysis. The work gives a useful indication of the current fluctuation range expected under worst case operation as required in the design of a direct ac-ac converter for contactless power transfer systems.