A general multi-phase coupled-resonant-tank resonant converter

A general multi-phase Coupled-Resonant-Tank (CRT) converter is proposed to achieve automatic current sharing. There are Y-style or Δ-style structures. The series inductor (or capacitor) of each phase are connected by a Coupled impedance which is inductor, capacitor or short-circuit. For easy understanding, a two-phase CRT LLC resonant converter is made as an example to analyze the current sharing performance. There are three types including eight topologies derived from CRT LLC converter. The coupled impedance of each phase can be instead of open-circuit, short-circuit and other inductor or capacitor. The Fundamental Harmonic Analysis (FHA) is utility to estimate the current sharing performance. A 600W, 12V two-phase LLC converter with short-circuit coupled impedance prototype is built. The prototype verified the feasibility and demonstrated advantages of the proposed concept.