Three-level LLC series resonance DC/DC transformer

This invention LLC serial resonance DC/DC converter includes a bleeder capacitor, an inverter composed of four serial switches, a resonance circuit, a clamp, an isolation transformer, a commutating circuit and a filter, capable of realizing large input/output voltage regulation sphere with small frequency variable sphere by LLC resonance circuit with dual intrinsic resonance frequency, at the same time, the switch is effectively clamped by a pair of clamp diodes, so that each switch voltage stress is half of the input voltage and ZVS is realized in all sphere without any additional circuit, the commutation diode works at the ZCS state.