| 摘要 |
The transformer 5 used for the present invention, comprises a core of E-shaped first and second core halves 5 g , 5 h coupled together in opposed relation to each other to form a closed magnetic circuit or circuits for supporting primary and secondary windings 5 a , 5 b wound around first and second core halves 5 g , 5 h; and a gap 5 n defined between end surfaces 5l , 5 m of first and second core halves 5 g , 5 h by spaced relation of end surfaces 5l , 5 m to also form a reduced section area 5 v by contacting the end surfaces 5l , 5 m. When a large amount of electric current flows through resonant series circuit 14 , reduced section area 5 v comes to magnetic saturation to reduce an excitation inductance 5 f of transformer 5 , more increase excitation current I<SUB>LP </SUB>and thereby perform steady operation in any load condition. When a small amount of electric current flows through resonant series circuit 14 , excitation inductance 5 f of transformer 5 is increased to repress excitation current I<SUB>LP</SUB>, thereby reducing power loss during light or no load to improve power conversion efficiency during light load. |
