GLEICHSTROM-LEISTUNGSTRANSFORMATOR

摘要

PCT No. PCT/SE90/00710 Sec. 371 Date Apr. 22, 1992 Sec. 102(e) Date Apr. 22, 1992 PCT Filed Nov. 2, 1990 PCT Pub. No. WO91/07807 PCT Pub. Date May 30, 1991.A DC/DC power transformer is provided which is an arrangement for direct transformation of high electric power from one DC voltage level to another DC voltage level without an intermediate AC voltage network. The DC voltage is today basically used for transmission of high electric power at long distances. The DC voltage levels for these transmissions are normally high. The DC/DC power transformer allows several DC voltage levels to be used in one and the same DC voltage network. The principle for this arrangement is that the valve windings (43, 45) from one or several converter transformers (47) are connected to two valve bridges, which generate opposing cyclically variating magnetic flows in the transformer cores (44). One of the valve bridges is operated as an inverter (42) and the other as a rectifier (46) and in this manner the power is transformed from one DC voltage level (Ud1) to another (Ud2). At high voltage levels the leakage inductances in the transformers will be high as a consequence of the insulation levels and therefore special arrangements must be made in order to commutate the magnetic energy from one phase of the transformer to another without creating great losses.