DC-DC converter with integrated transformer assembly composed of transformer pair

• US 7,907,042 B2
• Filed: 10/30/2007
• Issued: 03/15/2011
• Est. Priority Date: 10/31/2006
• Status: Expired due to Fees

• Current Assignee: DENSO Corporation, Nippon Soken, Inc. (DENSO Corporation)
• Original Assignee: DENSO Corporation, Nippon Soken, Inc. (DENSO Corporation)
• Inventors: Kawasaki, Koji, Yamashita, Tsuyoshi
• Primary Examiner(s): Berhane; Adolf
• Assistant Examiner(s): Mehari; Yemane
• Application Number:
  US11/928,259
• Publication Number:
  US 20080101097A1
• Time in Patent Office: 1,232 Days
• Field of Search: 363/16, 363/17, 363/20, 363/21.01, 363/22, 363/24, 363/49, 363/50, 336/200.212, 336220-223
• US Class Current: 336/200
• CPC Class Codes: H01F 17/043 with two, usually identical or nearly identical parts enclosing completely the coil (pot cores)
• CPC Class Codes: H01F 27/255 made from particles H01F27/26 takes precedence
• CPC Class Codes: H01F 30/04 having two or more secondary windings, each supplying a separate load, e.g. for radio set power supplies
• CPC Class Codes: H01F 30/06 characterised by the structure
• CPC Class Codes: H01F 30/12 Two-phase, three-phase or polyphase transformers
• CPC Class Codes: H02M 3/01 Resonant DC/DC converters
• CPC Class Codes: H02M 3/33569 having several active switching elements H02M3/3353 takes precedence
• CPC Class Codes: H02M 3/33571 Half-bridge at primary side of an isolation transformer
• CPC Class Codes: H02M 7/003 Constructional details, e.g. physical layout, assembly, wiring or busbar connections

Abstract

In an integrated transformer assembly, a common coil member has a first portion alternately wound, for each one electromagnetic turn, around the first core member and around the second core member. The first portion of the common primary coil member wound around the first core member is magnetically linked to the first magnetic path thereof so as to constitute a first primary coil. The first portion of the common primary coil member wound around the second core member is magnetically linked to the second magnetic path thereof so as to constitute a second primary coil. The first and second primary coils are connected in series. A secondary coil member has first and second secondary coils. The first and second secondary coils are arranged to be magnetically linked to the first and second primary coils of the common primary coil member, respectively.

Claims

1. An integrated transformer assembly comprising:

a first core member constituting a first magnetic path;

a second core member constituting a second magnetic path, the second magnetic path being separated from the first magnetic path, the first and second core members being physically separated from each other;

a common coil member having a first portion configured to be alternately wound, for each one electromagnetic turn, around the first core member and around the second core member, the first portion of the common primary coil member wound around the first core member being magnetically linked to the first magnetic path thereof so as to constitute a first primary coil, the first portion of the common primary coil member wound around the second core member being magnetically linked to the second magnetic path thereof so as to constitute a second primary coil, the first primary coil and the second primary coil being connected in series; and

a secondary coil member having a first secondary coil and a second secondary coil, the first and second secondary coils being arranged to be magnetically linked to the first and second magnetic paths of the first and second core members, respectively.

2. An integrated transformer according to claim 1, wherein the common coil member is entirely configured to be alternately wound, for each one electromagnetic turn, around the first core member and around the second core member.

3. An integrated transformer according to claim 1, wherein the common coil member has a second portion configured to be sequentially wound, for each one electromagnetic turn, at least one of around the first core member and around the second core member, the second portion of the common primary coil member wound at least one of around the first core member and around the second core member being magnetically linked to a corresponding at least one of the first and second magnetic paths so as to constitute part of a corresponding at least one of the first and second primary coils.

4. An integrated transformer assembly according to claim 1, wherein the secondary coil member has a portion configured to be alternately wound, for each one electromagnetic turn, around the first core member and around the second core member, the portion of the secondary coil member wound around the third part of the first core member constituting a first secondary coil of the secondary coil member to be magnetically linked to the first primary coil, the portion of the secondary coil member wound around the second core member constituting a second secondary coil of the secondary coil member to be magnetically linked to the second primary coil.

5. An integrated transformer assembly according to claim 1, wherein each of the first and second core members comprises:

a base having one surface;

a first pole arranged opposing the one surface of the base to be magnetically coupled thereto, the first pole extending away from the one surface of the base; and

a second pole arranged opposing the one surface of the base to be magnetically coupled thereto, the second pole extending away from the one surface of the base in parallel to the first pole,

the first pole of the first core member and that of the second core member being arranged opposing each other with a first gap therebetween,

the second pole of the first core member and that of the second core member being arranged opposing each other with a second gap therebetween.

6. An integrated transformer assembly according to claim 5, wherein each of the first and second core members further comprises:

a third pole arranged opposing the one surface of the base to be magnetically coupled thereto, the third pole extending away from the one surface of the base in parallel to the first pole, the second and third poles being aligned across the first pole,

the third pole of the first core member and that of the second core member being arranged opposing each other with a third gap therebetween.

7. An integrated transformer assembly according to claim 5, wherein the first pole of the first core member and that of the second core member have a same length, the second pole of the first core member and that of the second core member have a same length, the first and second poles of the first core member are aligned with those of the second core member in their length directions with the first and second gaps therebetween, respectively.

8. An integrated transformer assembly according to claim 1, wherein each of the first and second core members comprises:

a base having one surface;

a first pole arranged opposing the one surface of the base to be magnetically coupled thereto, the first pole extending away from the one surface of the base; and

a second pole member arranged opposing the one surface of the base to be magnetically coupled thereto, the second pole member extending away from the one surface of the base in parallel to the first pole, the second pole member having one side facing the first pole, the one side of the second pole member being circumferentially curved inwardly in a direction orthogonal to the magnetic path therein,

the first pole of the first core member and that of the second core member being arranged opposing each other with a first gap therebetween,

the second pole member of the first core member and that of the second core member being arranged opposing each other with a second gap therebetween.

9. An integrated transformer assembly according to claim 8, wherein the first pole of each of the first and second core members has one side facing the circumferentially curved one side of the second pole, the one side of the first pole being circumferentially curved outwardly toward the one side of the second pole in a direction orthogonal to the magnetic path therein, the one side of the second pole and the one side of the first pole of the first core member providing a substantially annular space therebetween, the one side of the second pole and the one side of the first pole of the second core member providing a substantially annular space therebetween, the first portion of the common primary coil member being installed in the annular space between the one side of the second pole and the one side of the first pole of the first core member and in the annular space between the one side of the second pole and the one side of the first pole of the second core member.

10. An integrated transformer assembly according to claim 1, wherein the first primary coil and the second primary coil are configured to be alternately wound, for each spatially half turn, around the first core member and around the second core member.

11. A DC to DC converter comprising:

an integrated transformer assembly according to claim 1, the first primary coil, the first secondary coil, and the first core member constituting a first transformer, the second primary coil, the second secondary coil, and the second core member constituting a second transformer;

an inverter circuit provided with at least one switching element via which input DC power is supplied, the inverter circuit being configured to turn the at least one switching element on and off in accordance with a predetermined duty cycle to convert the input DC power into AC power, thus supplying the converted AC power to the first and second primary coils of the first and second transformers, the first and second transformers being configured to alternately execute a transformer operation and a reactor operation so as to generate secondary AC power in the first and second secondary coils of the integrated transformer assembly; and

a rectifier configured to rectify the secondary AC power generated in the first and second secondary coils to thereby output DC power.

12. A DC to DC converter according to claim 11, wherein the input DC power is supplied to the inverter circuit from a DC power source, the first primary coil includes a first primary winding and a second primary winding, the second primary coil includes a third primary winding and a fourth primary winding, one end of the first primary winding and one end of the third primary winding are connected to each other in series, one end of the second primary winding and one end of the fourth primary winding are connected to each other in series, the other end of third primary winding and the other end of the fourth primary winding are connected to each other so as to constitute a common terminal, the other end of the first primary winding is connected to a positive terminal of the DC power source, and the other end of the second primary winding serves as an individual terminal of the series-connected second and fourth primary windings, and wherein the inverter circuit comprises:

a first switching element to establish a connection between the common terminal and a negative terminal of the DC power source;

an active clamp circuit provided with a second switching element and a first capacitor connected to each other in series, the active clamp circuit being configured to;

establish a connection between the common terminal and the individual terminal of the series-connected second and fourth primary windings; and

bypass, when the first switching element is turned off, a current flowing through the first switching element just before the first switching element being turned off; and

a second capacitor to establish a connection between the individual terminal of the series-connected second and fourth primary windings and the negative terminal of the DC power source.

13. A DC to DC converter comprising:

an integrated transformer assembly comprising;

a core constituting a magnetic path, the core comprising;

a pair of first and second bases, each base having one surface, the first and second bases being separated from each other;

a pair of first and second poles each arranged opposing the one surface of a corresponding one of the first and second bases to be magnetically coupled thereto, the first and second poles extending away from the one surface of a corresponding one of the first and second bases, the first and second poles being arranged opposing each other with a first gap therebetween, each of the first and second poles having a substantially semicircular cross section orthogonal to the magnetic path in a corresponding one of the first and second poles, the first and second poles with the gap collectively having one of a substantially circular cross section and a substantially ellipsoidal cross section, the one of the substantially circular cross section and the substantially ellipsoidal cross section being orthogonal to the magnetic path in each of the first and second poles; and

a pair of pole members each arranged opposing the one surface of a corresponding one of the first and second bases to be magnetically coupled thereto, the second pole member extending away from the one surface of a corresponding one of the first and second bases, the second pole member at least partially surrounding the pair of first and second poles;

the first base, the first pole and one of the pole members constituting a first core member, the second base, the second pole and the other of the pole members constituting a second core member, the first core member and the second core member being physically separated from each other;

a primary coil member composed of a first primary coil and a second primary coil connected to each other in series, the first and second primary coils being collectively wound around the paired first and second poles, the first primary coil being magnetically linked to the magnetic path of the first pole, the second primary coil being magnetically linked to the magnetic path in the second pole; and

a secondary coil member composed of a first secondary coil and a second secondary coil, the first and second secondary coils being wound around the first and second poles to be magnetically linked to the magnetic paths of the first and second poles, respectively, the first primary coil, the first secondary coil, and the core constituting a first transformer, the second primary coil, the second secondary coil, and the core constituting a second transformer;

an inverter circuit provided with at least one switching element via which input DC power is supplied, the inverter circuit being configured to turn the at least one switching element on and off in accordance with a predetermined duty cycle to convert the input DC power into AC power, thus supplying the converted AC power to the first and second primary coils of the first and second transformers, the first and second transformers being configured to alternately execute a transformer operation and a reactor operation so as to generate secondary AC power in the first and second secondary coils of the integrated transformer assembly; and

a rectifier configured to rectify the secondary AC power generated in the first and second secondary coils to thereby output DC power.

14. A DC to DC converter according to claim 13, wherein one wire strap is configured to be alternately wound, for each one electromagnetic turn, around the first pole and around the second pole, a portion of the one wire strap wound around the first pole constituting the first primary coil, another portion of the one wire strap wound around the second pole constituting the second primary coil.