As the advantages of zero-current-switching and zero-voltage-switching, the LCLC resonant converters are widely used in power supplies of Travelling-Wave Tubes(TWT). However, the problems such as the reverse resonant current and the non-zero resonant current in the converter drop the efficiency. In this paper, the above problems are explained by the working principle of the converter and the solutions to the problems are also given. Based on the simulations, empirical data is given to guide the design of th...