Three-phase H-bridge assembly and method of assembling the same

• US 6,456,515 B1
• Filed: 11/27/2000
• Issued: 09/24/2002
• Est. Priority Date: 11/27/2000
• Status: Expired due to Fees

• Current Assignee: Briggs & Stratton Corporation
• Original Assignee: Briggs & Stratton Corporation
• Inventors: Rose, Robert E. Sr.
• Primary Examiner(s): Han, Jessica
• Application Number:
  US09/723,359
• Time in Patent Office: 666 Days
• Field of Search: 363/55, 363/56.01, 363/56.02, 363/141, 363/144, 363/147, 257/706, 257/707, 257/713, 361/704, 361/707, 361/709, 361/711, 361/712, 361/719
• US Class Current: 363/144
• CPC Class Codes: H02M 7/003 Constructional details, e.g. physical layout, assembly, wiring or busbar connections

Abstract

The invention provides a bridge assembly for a three-phase motor. The assembly includes a first subassembly having a first terminal plate, a second subassembly having a second terminal plate, a third subassembly having a third terminal plate and a fourth subassembly having a bus terminal plate. Each of the terminal plates is electrically isolated from the other terminal plates, and at least one of the first, second, third and bus terminal plates acts as a heat sink. The assembly further includes first, second, third, fourth, fifth and sixth switching devices interconnected to at least one of the terminal plates. Each switching device has a heat generating surface in thermal communication with one of the first, second, third and bus terminal plates. The assembly further includes a fifth subassembly interconnected with the first, second, third, and fourth subassemblies.

Claims

1. A bridge assembly for a three-phase motor, comprising:

a first subassembly including a first terminal plate, a second subassembly including a second terminal plate, a third subassembly including a third terminal plate and a fourth subassembly including a bus terminal plate, each of the terminal plates being electrically isolated from the other terminal plates, and at least one of the first, second, third and bus terminal plates acting as a heat sink; and

first, second, third, fourth, fifth and sixth switching devices interconnected to at least one of the terminal plates, each switching device having a heat-generating surface in thermal communication with one of the first, second, third and bus terminal plates; and

a fifth subassembly interconnected with the first, second, third and fourth subassemblies, the fifth subassembly having a bus board.

2. A bridge assembly as in claim 1, further comprising:

six resistors connected in circuit resulting in a bridge circuit.

3. A bridge assembly as in claim 1, wherein the first subassembly includes the first switching device interconnected with the first terminal plate, the second subassembly includes the second switching device interconnected with the second terminal plate, the third subassembly includes the third switching device interconnected with the third terminal plate, and the fourth subassembly includes the fourth switching device interconnected with the bus terminal plate.

4. A bridge assembly as in claim 3, wherein the fourth subassembly includes the fifth and sixth switching devices interconnected with the bus terminal plate.

5. A bridge assembly as in claim 4, wherein the first subassembly further includes a seventh switching device interconnected with the first terminal plate, the second subassembly further includes an eight switching device interconnected with the second terminal plate, the third subassembly further includes a ninth switching device interconnected with the third terminal plate, and the fourth subassembly further includes tenth, eleventh and twelfth switching devices interconnected with the bus terminal plate, wherein each switching device has a heat generating surface, and wherein each terminal plate acts as a heat sink.

6. A bridge assembly as in claim 5, wherein the first and seventh switching devices are electrically connected in parallel, wherein the second and eighth switching devices are electrically connected in parallel, wherein the third and ninth switching devices are electrically connected in parallel, wherein the fourth and tenth switching devices are electrically connected in parallel, wherein the fifth and eleventh switching devices are electrically connected in parallel, and wherein the sixth and twelfth switching devices are electrically connected in parallel.

7. A bridge assembly as in claim 3, wherein the first, second, third and fourth subassemblies are interconnected with the fifth subassembly by a fastener.

8. A bridge assembly as in claim 1, wherein the bus board includes a one-sided copper clad printed circuit board.

9. A bridge assembly as in claim 1, wherein each subassembly includes a terminal.

10. A bridge assembly as in claim 1, wherein the bus board includes a conducting surface.

11. A bridge assembly as in claim 10, wherein the bus board includes a nonconductive surface disposed next to each switching device.

12. A bridge assembly as in claim 1, wherein each of the first, second, third and bus terminal plates act as a heat sink.

13. A bridge assembly as in claim 12, wherein the first, second, third and bus terminal plates are thermally isolated.

14. A bridge assembly as in claim 1, wherein the switching devices include transistors.

15. A bridge assembly as in claim 14, wherein the transistors are field-effect transistors.

16. A method of assembling a bridge circuit for a three-phase motor, comprising:

forming first, second, third and fourth subassemblies, the first subassembly including a first terminal plate, the second subassembly including a second terminal plate, the third subassembly including a third terminal plate, and the fourth subassembly including a bus terminal plate, at least one of the terminal plates acting as a heat sink, the forming step including

interconnecting a first switching device to one of the first, second, third, and bus terminal plates,

interconnecting a second switching device to one of the first, second, third, and bus terminal plates,

interconnecting a third switching device to one of the first, second, third, and bus terminal plates,

interconnecting a fourth switching device to one of the first, second, third, and bus terminal plates,

interconnecting a fifth switching device to one of the first, second, third, and bus terminal plates,

interconnecting a sixth switching device to one of the first, second, third, and bus terminal plates; and

interconnecting the first, second, third and fourth subassemblies to a fifth subassembly.

17. A method as set forth in claim 16, further comprising:

temporarily mounting the first, second, third and bus terminal plates to a mounting structure, and

removing the first, second, third and fourth terminals from the mounting structure after the step of interconnecting the first, second, third and fourth subassemblies with the fifth subassembly.

18. A method as set forth in claim 17, wherein the step of interconnecting the subassemblies includes interconnecting each switching device to the fifth subassembly with a fastener.

19. A method as set forth in claim 16, wherein the first switching device is interconnected with the first terminal plate, the second switching device is interconnected with the second terminal plate, the third switching device is interconnected with the third terminal plate, and the fourth, fifth and sixth switching devices are interconnected with the bus terminal plate.

20. A method as set forth in claim 19, wherein each switching devices includes a heat generating surface, wherein each terminal plate acts as a heat sink, and wherein the steps of interconnecting the switching devices includes the step of interconnecting the respective heat generating surface in thermal communication with the respective first, second, third and bus terminal plate.

21. A method as set forth in claim 19, further comprising:

connecting six resistors in circuit resulting in a bridge circuit.

22. A method as set forth in claim 19, wherein the forming step further includes:

interconnecting a seventh switching device to the first terminal plate;

interconnecting an eighth witching device to the second terminal plate;

interconnecting a ninth switching device to the third terminal plate; and

interconnecting tenth, eleventh and twelfth switching device to the bus terminal plate.

23. A method as set forth in claim 22, wherein the forming step further includes:

connecting the first and seventh switching devices in parallel;

connecting the second and eighth switching devices in parallel;

connecting the third and ninth switching devices in parallel;

connecting the fourth and tenth switching devices in parallel;

connecting the fifth and eleventh switching devices in parallel; and

connecting the sixth and twelfth switching devices in parallel.

24. A method as set forth in claim 16, wherein each switching device includes a transistor.

25. A method as set forth in claim 24, wherein the transistor is a field-effect transistor.

26. A method as set forth in claim 24, wherein each switching device includes a field-effect transistor (FET) having a source, a drain and a gate, and wherein the method comprises:

electrically connecting the drain of each switching device to the respective terminal plate;

electrically connecting the source of the fourth transistor to the first terminal plate;

electrically connecting the source of the fifth transistor to the second terminal plate;

electrically connecting the source of the and sixth transistor to the third terminal plate; and

electrically connecting the source of the first, second and third transistors to a bus board of the fifth subassembly.

27. A method as set forth in claim 26, wherein the bus board includes a conductive surface.

28. A method as set forth in claim 16, further comprising creating a fifth subassembly by interconnecting a terminal to a bus board.

29. A method as set forth in claim 28, wherein the bus board includes a one-sided copper clad printed circuit board.