Three coil bridge transformer

• US 5,225,971 A
• Filed: 01/08/1992
• Issued: 07/06/1993
• Est. Priority Date: 01/08/1992
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Spreen, James H.
• Primary Examiner(s): BEHA JR, WILLIAM
• Application Number:
  US07/818,017
• Time in Patent Office: 545 Days
• Field of Search: 363/17, 363/37, 363/126, 336/184, 336/212, 336/232
• US Class Current: 363/17
• CPC Class Codes: H01F 2038/026 non-linear inductive arrangements for converters, e.g. with additional windings
• CPC Class Codes: H01F 30/10 Single-phase transformers H01F30/16 takes precedence
• CPC Class Codes: H02M 7/003 Constructional details, e.g. physical layout, assembly, wiring or busbar connections

Abstract

The magnetic core of the transformer is an E--E shaped core. The primary winding of the transformer is divided into three substantially identical planar coils, each coil being wound on one of the three separate core posts. The coils are wired in series such that a current in the primary winding will induce substantially identical magnetic fluxes in the two outer core posts, and an opposite flux in the center post. The secondary of the transformer is formed by a contact plate and a conductor frame which provide conducting paths through the window regions of the E--E core. The bottom of the core is mounted in a recess in the conductor frame. Positioned within in the conductor frame are four rectifiers which make electrical connections to the secondary contact plate. When the transformer delivers power, the voltage on the primary winding will be divided 1/4 on each of the outer coils and 1/2 on the center coil post. During this time only two of the rectifiers will be conducting current. During freewheel times, with no primary voltage, the load current will divide evenly among the four rectifiers. During commutate intervals, between freewheel and on times, the voltage on the primary winding will divide evenly among the three coils. This novel transformer permits a switch mode power supply to supply more power while providing more even cooling.

Claims

1. A transformer comprising:

a core of magnetic material having a left post, a center post, a right post, a top structure and a bottom structure, said core defining two window regions;

said core posts being respectively encircled by left, center and right primary coils, said coils forming a primary winding;

a contact plate providing conduction paths from a first end of said contact plate on a first side of said core, through said window regions to a second end of said contact plate on a second side of said core; and

said second end of said contact plate being electrically connected to a plurality of rectifiers.

2. A transformer as described in claim 1 wherein:

said coils of said primary winding being substantially co-planar and connected in series, whereby current flows in a same relative direction in said left and right primary coils, and in an opposite relative direction in said center primary coil.

3. A transformer as described in claim 1 wherein:

said bottom structure of said core is disposed in a first recess in a conductor frame; and

said contact plate is disposed in a second recess in said conductor frame.

4. A transformer as described in claim 3 wherein:

a first rectifier is positioned beneath said left primary coil;

second and third rectifiers being positioned beneath said center primary coil; and

right primary coil.

5. A transformer as described in claim 4 wherein:

said rectifiers and said first end of said contact plate are connected to an output circuit comprising an output filter and a load.

6. A power supply with increased cooling and power capability comprising:

a first conversion means for converting low frequency alternating current into high frequency alternating current;

a transformer having as an input said high frequency alternating current, said transformer providing transformed high frequency alternating current as an output;

said transformer having a core of magnetic material having a left post, a center post, a right post, a top structure and a bottom structure, said core defining two window regions;

said core posts being respectively encircled by left, center and right primary coils, said coils forming a primary winding;

a contact plate providing conduction paths from a first end of said contact plate on a first side of said core, through said window regions to a second end of said contact plate on a second side of said core; and

said second end of said contact plate being electrically connected to a plurality of rectifiers, said rectifiers forming a second conversion means for converting said transformed high frequency alternating current into direct current.

7. A power supply in accordance with claim 6 wherein:

said coils of said primary winding being substantially co-planar and connected in series, whereby current flows in a same relative direction in said left and right primary coils, and in an opposite relative direction in said center primary coil.

8. A power supply in accordance with claim 7 wherein:

said bottom structure of said core is disposed in a first recess in a conductor frame; and

said contact plate being disposed in a second recess in said conductor frame.

9. A power supply in accordance with claim 8 wherein:

a first rectifier being positioned beneath said left primary coil;

second and third rectifiers being positioned beneath said center primary coil; and

a fourth rectifier being positioned beneath said right primary coil.

10. A power supply in accordance with claim 9 further comprising;

a control means connected to said first conversion means for providing regulation of said direct current.

11. A power supply in accordance with claim 9 wherein said first conversion means further comprises;

an alternating current rectifying means connected to an alternating current power main for supplying rectified direct current;

a bulk storage means for storing said rectified direct current;

a switching means connected to said bulk storage means, said switching means supplying said high frequency alternating current to said transformer.

12. A power supply in accordance with claim 9 further comprising:

a filtering means following said second conversion means for filtering said direct current.