A Novel Bidirectional Wider Range of Boost-Buck Three-Level LCC Resonant Converter as an Energy Link

In order to maintain different voltage levels between the front and rear dc terminal bus derived from new energy industry, a novel bidirectional wider range of boost-buck three-level LCC resonant converter as an energy link is proposed by combining the LCC resonant tank module with a particular three-level coupling cascaded neutral point clamping active bridges, which is composed of two three-level neutral point clamping bridge arms. Furthermore, the converter can, respectively, establish forward LCC and backward SRC working modes to maintain unified wider bidirectional voltage gain range between the input and output by asymmetric structure of LCC resonant tank module that boost-voltage is enabled by equivalent principle of conventional LCC resonant converter and buck-voltage is enabled by equivalent principle of conventional series resonant converter, while, a unified bidirectional boost-buck voltage gain matching control strategy is designed with an optimization about parameters of LCC resonant tank module under realizing of zero voltage switching-on and reducing of reactive power losses. Finally, according to the simulation platform and experimental prototype, it can be shown that the practical voltage gain is closed to the theoretical designed gain and converter has good dynamic performances after realizing of soft-switching in each mode.