Transformer unit, and power converting device

摘要

A transformer unit and a power converting device, which lessen the influence of noise caused by an external magnetic flux, while reducing the temperature dependency of a coupling coefficient, and which transfer signals while insulating a low-voltage and a high-voltage side electrically. Air-core type insulated transformers have a first and second winding of a primary winding as a sending side and a first and second winding of a secondary winding as a receiving side. The windings of the primary winding are connected in parallel and are wound so that the directions of magnetic fields generated by an exciting current oppose each other. The windings of the secondary winding are wound so that electromotive forces to be generated by an external magnetic flux cancel each other, and are connected in series so as to raise the electromotive forces by a signal magnetic flux generated by the primary winding.