MULTI-PHASE LLC RESONANT CONVERTER CIRCUIT

To provide a multi-phase LLC resonant converter circuit capable of suppressing an increase in a resonance current at a step-up operation of an input voltage and switching a multi-phase operation and a single-phase operation.SOLUTION: A multi-phase LLC resonant converter circuit 10 comprises: first to third LLC resonant converters each of which includes series circuits S1-S3 to which a first switch and a second switch connected in parallel to a DC power supply 30 are connected in series, high-frequency transformers T1-T3 including a primary-side winding and a secondary-side winding, resonant circuits 41-43 including resonant reactors Lr1-Lr3 connected between a connection point between the first switch and the second switch and one end of the primary-side winding and resonant capacitors Cr1-Cr3 in which one end is connected to the other end of the primary-side winding, and rectification circuits 51-53 rectifying an output from the secondary-side winding; a neutral line N1 connecting other ends of the resonant capacitors of the first to third LLC resonant converters to each other; and a neutral line reactor Ln connected between the neutral line and a power line of the DC power supply.SELECTED DRAWING: Figure 1 【課題】入力電圧の昇圧動作時に共振電流の増加を抑制でき、多相動作と単相動作を切り換え可能な多相ＬＬＣ共振コンバータ回路を提供する。【解決手段】多相ＬＬＣ共振コンバータ回路１０は、直流電源３０に並列に接続される第１スイッチと第２スイッチが直列に接続された直列回路Ｓ１－Ｓ３と、一次側巻線と二次側巻線とを備えた高周波トランスＴ１－Ｔ３と、第１スイッチと第２スイッチとの接続点と一次側巻線の一端との間に接続された共振リアクトルＬｒ１－Ｌｒ３と一次側巻線の他端に一端が接続された共振コンデンサＣｒ１－Ｃｒ３とを備えた共振回路４１－４３と、二次側巻線の出力を整流するための整流回路５１－５３とを備えた第１－第３のＬＬＣ共振コンバータと、第１－第３のＬＬＣ共振コンバータの共振コンデンサの他端を互いに接続した中性線Ｎ１と、中性線と直流電源の電源ラインとの間に接続された中性線リアクトルＬｎとを備える。【選択図】図１