RU2122760C1 - Transformer unit - Google Patents

Abstract

FIELD: converting units including frequency step-up inductive devices. SUBSTANCE: transformer unit has toroidal transformer and current-carrying buses connecting transformer to load. Transformer secondary winding is formed by two interconnected bifilar conducting strips. Annular depression made in at least one of strips accommodates toroidal core with primary winding distributed over its surface. Current- carrying buses insulated from each other and from secondary winding are formed by sections of bifilar strips placed on external side of transformer. In this way, secondary winding and current-carrying buses are built integral. EFFECT: reduced loss, simplified design. 2 dwg

Description

 The invention relates to electrical engineering, in particular to transformers, and can be used in induction installations of high frequency.

 Known transformer devices containing a toroidal core on which the primary winding and one turn of a high-current secondary winding are made in the form of a rod passing through the window of the core [1].

 This device has a low efficiency, since the coil of the secondary winding has a significant active and inductive resistance.

 A transformer device based on a toroidal core is known, the high-current secondary winding of which is made in the form of a volume coil, covering the entire primary winding [2].

 This device has a higher coupling coefficient between the windings and lower dissipation inductance. It is the closest to the invention in technical essence and the achieved result.

 In this device, the volume coil is assembled from several mechanically connected blanks; places of their connections, which are also electrical connectors, have increased contact resistance and introduce additional losses into the high-current circuit of the secondary winding. Additional losses are allocated in the places of fastening of the terminals of the secondary winding and in the volumetric current-supplying buses connecting the secondary winding with the load. As a result, the efficiency of the device is low, and its design is difficult to implement.

 The objective of the invention is to reduce losses and simplify the design of the device.

 To solve these problems, a transformer device containing a toroidal core with a primary winding distributed on its surface, located in a ring-shaped recess made in at least one of two bifilar located conductive plates, forming a single-turn secondary winding with current-carrying tires for connection to the load, sections conductive plates on the inner side of the toroidal core with the primary winding form an electrical connection between by itself, and the sections located on its outer side are isolated from each other and form current-carrying tires.

 Two wide plates of electrically conductive material, for example, copper, provided with a recess in the shape of a circular ring, cover a continuous layer of the entire outer surface of the primary winding uniformly distributed on the toroidal core, thereby achieving a high coupling coefficient between the windings and a decrease in the leakage inductance.

 In the proposed device, the volumetric turn consists of blanks of simple construction on the basis of two electrically conductive plates, mechanically and electrically connected only on the inside of the toroidal transformer. On the outside of the toroidal transformer, these electrically conductive plates are not electrically connected to each other and act as bifilarly arranged flat current-carrying buses, which are an inextricable continuation of the terminals of a high-current winding. This design helps to reduce the parasitic inductance of a high current circuit. The implementation of current-carrying tires and high-current windings in a single design gives a significant gain in reducing contact connections in a high-current circuit. Thus, a simplification of the design of the device and reduction of power losses are achieved. In addition, the said plates, which perform the functions of a volumetric turn and busbars, form a developed surface and additionally provide the function of heat removal of power losses released in the transformer device.

 In FIG. 1 is a drawing of the proposed device with an asymmetric tire design; in FIG. 2 - with a symmetrical tire design.

 A toroidal core 1 (Fig. 1) with a primary winding 2 distributed evenly over the entire surface of the toroidal core 1 and separated from the latter by a thin layer of insulation 3, is tightly placed in a ring-shaped recess formed in the conductive plate 4. The second plate 5 is pulled from the first 4 so that the core 1 with the winding 2 are located between them. The sections of plates 4 and 5, located on the inner side of the toroidal transformer, form an electrical contact connection with each other, and the sections located on the outside of the transformer are isolated from each other by a thin layer of insulation 6. The same thin layer of insulation separates the outer surface of the primary winding 2 from conductive plates 4 and 5. At the ends of the plates 4 and 5, flanges 7 and 8 are provided, to which the load is connected, in particular, an inductor can be attached. On the flat sections of both plates are tubes 9 and 10 for liquid cooling of the device.

 In a device with a symmetrical tire design (see Fig. 2), two structurally identical plates with a recess 4 and 5 are used. In both versions, a thin layer of insulation 6 can be applied directly to the inner surfaces of the plates 4 and 5.

 The device operates as follows. An increased frequency voltage is supplied to the primary winding 2, under the action of which a current arises in it, creating a magnetic flux and inducing EMF in a high-current winding. As a result, an alternating current occurs in the load connected to the contact flanges 7 and 8.

 In the case of a symmetrical design of the device, the density of the spreading current on identical sections of the plates 4 and 5 is the same, which contributes to the most complete compensation of the parasitic inductance of the tires due to the bifilar effect. A similar compensation effect is observed as a result of the action of oppositely flowing currents in the layer of the primary winding 2 and the sections of the plates 4 and 5 covering it, which are a layer of a single-turn high-current winding. This achieves an effective reduction in the voltage drop in the current-carrying sections of the high-current circuit and the installed power of the transformer.

 With an asymmetric busbar design, when the recess is formed on only one plate, the pattern of current spreading in plates 4 and 5 will be slightly different, as a result there will only be partial compensation for the inductance of the current-carrying tires. In the case of relatively low operating frequencies, the effect of partial compensation may be sufficient, and the use of an asymmetric tire design is justified.

 In both cases, the assembly of the device is carried out from preformed blanks, which can be performed by various technological methods. In the case of a symmetrical design, when two identical blanks are used, the procedure for their fastening may be somewhat difficult due to the small size of the inner region of the toroidal transformer. More free access to the mounting points of the plates allows asymmetric tire design.

 Using the design of a high-current winding of a power transformer assembled from billets; Combining additional functions of current supply and heat removal, it allows to simplify the design and assembly of the entire device, significantly reduce spurious parameters and increase the efficiency of the device.

Sources of information
1. A.S. N 230960 (USSR), MKI H 01 F 27/02, 1968.

 2. A.S. N 734822 (USSR), MKI H 01 F 27/30, H 01 F 31/00, 1980 (prototype).

Claims (1)

 A transformer device containing a toroidal core with a primary winding distributed on its surface, located in a ring-shaped recess made in at least one of two bifilar located electrical conductive plates, forming a single-turn secondary winding with current-carrying buses for connecting to the load, characterized in that the sections conductive plates on the inner side of the toroidal core with the primary winding form an electrical connection between oboj, and portions located on its outer side, insulated from each other and form busbars.

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