Composite transformer

A combined type transformer comprising:

• a plurality of windings;
• a transformer core including a plurality of transformer-core legs which extend in a direction of axes of the plurality of windings and around which the plurality of windings are wound;
• a plurality of inductor cores including a plurality of inductor-core legs which extend in the direction of the axes of the plurality of windings, around which the plurality of windings are wound, and each of which is arranged adjacent to one of the plurality of transformer-core legs in a direction perpendicular to the direction of the axes of the plurality of windings;
• wherein a plurality of core legs are formed with the plurality of transformer-core legs and the plurality of inductor-core legs and the plurality of windings are wound around the plurality of core legs in such a manner that magnetic fluxes are produced in the plurality of transformer-core legs and the plurality of inductor-core legs when current flows through the plurality of windings, and the plurality of core legs and the plurality of windings form a single transformer and a plurality of inductors;
• the plurality of transformer-core legs in the transformer core are arranged in an array in a direction perpendicular to the direction of the axes of the plurality of windings, the transformer core further includes a pair of transformer bases extending in the direction of the array and being opposed to each other and connected to both ends of each of the plurality of transformer-core legs in such a manner that closed magnetic circuits for magnetic fluxes produced in the plurality of transformer-core legs can be formed in the transformer core;
• each of the plurality of inductor cores includes one of the plurality of inductor-core legs, an outer core leg, and a pair of inductor bases, the outer core leg extends parallel to the one of the plurality of inductor-core legs in the direction of the axes of the plurality of windings and is arranged on an outer side of one of the plurality of windings wound around the one of the plurality of inductor-core legs, and the pair of inductor bases are connected to both ends of the one of the plurality of inductor-core legs and to both ends of the outer core leg in such a manner that a closed magnetic circuit for a magnetic flux produced in the one of the plurality of inductor-core legs can be formed in said each of the plurality of inductor cores;
• and
• the plurality of windings are wound around the plurality of core legs in such directions that the magnetic fluxes produced in the plurality of transformer-core legs cancel each other in the closed magnetic circuits in the transformer core in any combination of directions that the magnetic fluxes produced.