US 4,004,251 AGranted

Inverter transformer

AssigneeGeneral Electric Company

InventorsJoseph P. Hesler, Samuel M. Korzekwa

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Abstract

A transformer designed to operate with a pair of power switching transistors in a d.c. to a.c. inverter is described. The transformer has an assembled core whose closed magnetic path is branched. A flux steering winding is used to ensure the prior saturation of a first branch associated with a regenerative feedback winding. Prior saturation of this branch reduces the forward drive on the switching transistors prior to full core saturation and avoids the consequent switching stresses on the transistors. The cores of the transformer are made from parts which abut at the branches so that both preformed power and preformed control windings may be used in assembling the transformer. The transformer may be assembled from conventional core configurations, and is thus of relatively low cost. A core arrangement is also disclosed in which the cross-section of the individual branches of the core may be adjusted.

Claims10

Dependent claims

A transformer adapted to be coupled to a pair of switching devices to form an inverter having:

1. a core of substantially linear magnetic material providing a closed magnetic path along which a working cross-section is maintained for the principal flux, said path being divided for part of its length in two branches between which the principal flux may be steered with a relatively small magnetomotive force, said core being assembled from two members which are butted at the branch to permit encirclement of one of said branches by a preformed winding,
2. a center tapped primary power winding encircling said working cross-section, each end of which is adapted to be connected to an output electrode of one of a pair of alternately conducting electronic switches, and the center tap of which is adapted to be connected to a d.c. source to cause the principal flux in said core to alternate,
3. a secondary power winding encircling said working cross-section for deriving an alternating voltage output.
4. first control winding means adapted to be connected to said switches to cause alternate conduction, said winding encircling one branch and providing regenerative feedback during each conduction period which terminates when said one branch saturates, and
5. second control winding means encircling one of said branches for providing a magnetomotive force for causing said one branch to saturate first in each conduction period to remove the regenerative feedback before saturation of the working cross-section.

2 more elements

Dependencies are inferred from the claim text.