Characterization and control of self-oscillating contactless resonant converter with fixed voltage gain

To ensure reliable control under variable-load and variable-coupling-coefficient condition, a self-oscillating control method for contactless resonant converters is proposed and discussed. Base on the characterization of four basic compensation topologies, such as the voltage gain, transfer impedance, a simple and general self-oscillating control method for S/S, S/P and P/S topology is proposed. Theoretical and experimental results had shown that the proposed control strategy is capable to lock the switching frequency at load independent frequency. Besides the good regulation, the proposed control method can also realize high efficiency for minimal extra component introduced.