Patent ID: 8705251
Filing Date: 2014-04-22
Classification: H02M

Abstract:
1. A bidirectional DC/DC converter including a first voltage terminal to a fourth voltage terminal, and performing a forward-direction operation for converting a DC voltage applied to said first voltage terminal and a second voltage terminal to a prescribed DC voltage and supplying the DC voltage to a third voltage terminal and said fourth voltage terminal and a reverse-direction operation for converting a DC voltage applied to said third voltage terminal and said fourth voltage terminal to a prescribed DC voltage and supplying the DC voltage to said first voltage terminal and said second voltage terminal, comprising: an isolation transformer including a first winding and a second winding; a first bidirectional DC/AC conversion circuit connected between said first voltage terminal, said second voltage terminal and said first winding, for converting the DC voltage applied to said first voltage terminal and said second voltage terminal to an AC voltage and outputting the AC voltage to said first winding in said forward-direction operation, and rectifying and smoothing an AC voltage induced in said first winding and outputting the AC voltage to said first voltage terminal and said second voltage terminal in said reverse-direction operation; and a second bidirectional DC/AC conversion circuit connected between said third voltage terminal, said fourth voltage terminal and said second winding, for rectifying and smoothing an AC voltage induced in said second winding and outputting the AC voltage to said third voltage terminal and said fourth voltage terminal in said forward-direction operation, and converting the DC voltage applied to said third voltage terminal and said fourth voltage terminal to an AC voltage and outputting the AC voltage to said second winding in said reverse-direction operation, said second bidirectional DC/AC conversion circuit including a push-pull circuit including a first switching element and a second switching element coupled to opposing ends of said second winding respectively, and an up-conversion circuit coupled to said push-pull circuit, said third voltage terminal and said fourth voltage terminal, said up-conversion circuit including an inductor for allowing passage of a current through said second winding, said first switching element in an ON state and said second switching element in an ON state owing to stored magnetic energy, and a third switching element forming a current path going through said third voltage terminal, said inductor and said fourth voltage terminal but not through said first switching element and said second switching element as it is turned on, and in said reverse-direction operation, said third switching element repeating an ON state and an OFF state, and the ON state and the OFF state of said first switching element and said second switching element being switched while said third switching element is in the ON state.