Patent ID: 8013703

Claim:
An electric power conversion circuit which converts an electric power by transforming an input voltage and includes a first input-output connecting terminal and a second input-output terminal, the electric power conversion circuit comprising: a multi-parallel magnetic field cancellation type transformer comprising at least three coils connected in parallel, each generating magnetic flux when energized; at least three first energization control elements whose one ends are connected to the coils respectively, and whose other ends are connected to a negative electrode of the first input-output connecting terminal; at least three second energization control elements whose one ends are connected to the coils respectively, and whose other ends are connected to a positive electrode of the second input-output connecting terminal; and a core comprising three magnetic leg portions about which the coils are wound, and a base for fixing the three magnetic leg portions, wherein the direction of the magnetic flux generated from the coils wound on the three magnetic leg portions is opposite to each other in any couple selected from among the pieces of magnetic flux, so that the magnetic flux is cancelled out with each other.