Design and Operation of Bi-Directional CLLC Resonant Converter

A new topology known as CLLC has recently gained prominence, in which a capacitor in series is inserted on the secondary side which differs it from LLC converter. The primary side of the transformer has an inverter, while the secondary side has a rectifier, a variable load, and a capacitor is present which acts as filter. Similar to the LLC topology, a llc resonant tank is present which consists of passive components in series such as capacitor, inductor and a parallel magnetising inductor. It is type of DC-DC converter which has the advantage of reduced switching losses and switching noise and it is highly efficient and has an elevated power density but the design of this converter is complicated. In this paper a easier and simplified technique of design of resonant converter is proposed. This document provides a brief description of the operation of CLLC converter as well as detailed design instructions. A design example is provided along with the simulation waveforms. The simulation is carried out in PLECS software.