Variable-ratio transformer

摘要

The subject matter of the invention is a variable-ratio transformer which is designed as a multiple limb transformer. This variable-ratio transformer furthermore has at least one secondary winding which is fitted on a first core limb, a plurality of primary windings which are fitted on at least one further core limb, and a control unit for determining the winding voltages. In order to ensure reliable isolation of the mains side, the output side and the control side and in order to reduce the circuit complexity required, the invention stipulates that the magnetic flux in that core limb (S2) which is assigned to the secondary is equal to the geometric sum of the magnetic fluxes in all the core limbs (S1, S3) assigned to the primary, that each primary winding (N1, N3) consists of at least one elementary winding, that mains voltage is applied to at least one primary winding (N1) and the input voltages of the other primary windings (N3) are determined by means of an additional group of source windings (N1.1 to N1.n) which are magnetically coupled to the primary winding which is connected to the mains voltage, and that the control unit (St) is designed for amplitude-controlled and/or phase-controlled application of voltage to the primary windings (N1, N3). The amplitude control is preferably carried out step by step, each primary winding (N3) which is not connected to the mains voltage being assigned a phase-shifter stage composed of four switches (Si.k) which form a bridge, one of whose diagonals ... to the corresponding ... Original abstract incomplete. <IMAGE>