Power inverter with improved heat sink configuration

• US 6,038,156 A
• Filed: 06/09/1998
• Issued: 03/14/2000
• Est. Priority Date: 06/09/1998
• Status: Expired due to Term

• Current Assignee: Xantrex Technology Incorporated (Mission Critical Electronics LLC)
• Original Assignee: Heart Interface Corporation
• Inventors: Liang, Zhixiang, Inam, Haroon, Zheng, Raymond L., Gebenini, Edo P., Pringle, Bernie E., Rosebrough, Gerald E., Cronyn, Doris
• Primary Examiner(s): Wong, Peter S.
• Assistant Examiner(s): Vu, Bao Q.
• Application Number:
  US09/094,422
• Time in Patent Office: 644 Days
• Field of Search: 361/690, 361/704, 361/707, 361/709, 361/710, 257/718, 257/719, 257/726, 257/727, 363/133, 363/95, 363/97, 363/21, 363/24
• US Class Current: 363/133
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H02M 7/003 Constructional details, e.g. physical layout, assembly, wiring or busbar connections

Abstract

An inverter for producing AC power from a DC source is disclosed. The inverter uses a transformer and switches to convert current from a battery or other DC source into AC power that can be used to power household appliances or other devices. The primary windings of the transformer are directly connected to a heat sink to which the switches are mounted with electrical connection between the transformer and switches being via the heat sink. The connection point on the heat sink for the primary windings of the transformer is spatially removed from the locations of the switches to facilitate heat dissipation at both locations. The primary windings of the transformer are formed from a tape or ribbon-like conductor having a cross-sectional area that allows the construction of a relatively compact transformer while also providing primary conductors of relatively large cross section. Use of tape-like conductors in the primary windings significantly simplifies the interconnection of the end of the primary winding both to a bus bar and the heat sink. Since the tape-like conductor of the transformer can be bolted directly to the flat surface of a bus bar or heat sink without using an intermediate terminal or lug, and since a relatively large contact area is established, ohmic contact resistance is minimized thus reducing the generation of heat. In one embodiment, a wedge configuration is used to mount the switches of the primary windings to the heat sink. The mounting wedge includes two flexible plate-like sections that hold both the tab and the body of the switch against the adjoining side wall of the heat sink.

Claims

1. An inverter for converting DC to AC power, comprising:

a transformer with at least one primary winding and at least one secondary winding;

at least one switch coupled to a primary winding of the transformer for periodically interrupting the flow of DC current through the primary winding of the transformer such that a varying current results in the primary winding of the transformer; and

a heat sink, at least one of the switches being mounted to the heat sink for dissipating thermal energy generated by the at least one switch, the primary winding of the transformer being directly connected to the heat sink to form an electrical connection that is spatially removed from the location on the heat sink where the at least one switch is mounted such that the heat sink significantly dissipates heat generated at the connection between the primary winding and the heat sink before it reaches the location on the heat sink where the switch is mounted.

2. The inverter of claim 1, wherein the primary windings of the transformer are wound with a tape-like conductor.

3. The inverter of claim 2, wherein the primary winding is directly connected to the heat sink by a fastener that secures a flat section of the tape-like conductor of the primary winding to a substantially flat surface on the heat sink.

4. An inverter for converting DC to AC power, comprising:

a transformer with primary and secondary windings;

a switch for completing a circuit path between a primary winding of the transformer and a DC current source; and

a heat sink coupled between said primary winding of the transformer and said switch, the heat sink having a plurality of cooling fins, the primary winding being connected to the heat sink at a connection point on a first one of said cooling fins, said switch being mounted in electrical connection with a second one of said cooling fins, said first and second ones of said cooling fins being separated by at least one additional cooling fin of said plurality of cooling fins.

5. The inverter of claim 4, wherein the primary winding of the transformer is wound with a tape-like conductor.

6. The inverter of claim 5, wherein the primary winding is directly connected to the heat sink by using a fastener to secure a flat section of the tape-like conductor of the primary winding to a substantially flat surface on the heat sink.

7. An inverter for converting DC power to AC power, comprising:

a transformer with primary and secondary windings;

a switch for periodically completing a circuit path between a primary winding of the transformer and a DC current source; and

a heat sink, said primary winding being directly connected to the heat sink, said switch being mounted in thermal and electrical contact with the heat sink at a switch mounting location that spatially separates the connection between said primary winding and the heat sink from said switch mounting location by a distance that provides thermal isolation from heat generated by said switch and establishes sufficient cooling capabilities such that the heat generated at the connection between the primary winding and the heat sink is substantially dissipated before it reaches the switch mounting location.

8. The inverter of claim 7, wherein the primary winding is wound with tape wire.

9. A heat sink for an inverter for converting DC power to AC power, comprising:

a groove for receiving a wedge; and

a wedge with first and second flexible plate-like sections, the wedge being secured within the groove of the heat sink so as to fixably hold a transistor with a tab and body against the heat sink, the first plate-like section pressing the transistor tab against the heat sink and the second plate-like section pressing the transistor body against the heat sink.

10. The heat sink of claim 9, wherein the first plate-like section presses against the tab of the transistor with a sufficient force to allow good electrical conduction to the tab of the transistor.

11. An invter for converting DC to AC power, comprising:

a transformer with at least one primary winding that is wound from a tape-like conductor;

a switch coupled to the primary winding of the transformer for periodically altering the flow of current through the primary winding of the transformer;

a heat sink, said switch being mounted to the heat sink for dissipating thermal energy generated by said switch, the primary winding of the transformer being directly connected to the heat sink to form an electrical connection that is spatially removed from the location on the heat sink where said switch is mounted such that the heat sink significantly dissipates heat generated at the connection between the primary winding and the heat sink.

12. The inverter of claim 11, wherein the primary winding of transformer include two windings connected to one another to define a primary winding having a center tap, the center tap thereby including at least two tape-like conductors of the primary windings, the two tape-like conductors being electrically connected to the terminal of the DC source through the use of a single connector without requiring the use of an intermediate terminal or lug.

13. The inverter of claim 11, wherein the primary winding is directly connected to the heat sink by a fastener to electrically interconnect a flat section of the tape-like conductor of the primary winding with a substantially flat surface on the heat sink.

14. The inverter of claim 11, wherein the heat sink includes a groove and a wedge shaped for positioning within the groove, said wedge having at least first and second plate-like sections, the switch being mounted to the heat sink by the wedge with the first plate-like section pressing the body of the switch against a boundary wall of the heat sink groove and the second plate-like section pressing the tab of the switch against a body wall of the heat sink groove.

15. An inverter for converting DC to AC power, comprising:

a transformer with at least one primary winding and at least one secondary winding;

at least one switch coupled to a primary winding of the transformer for periodically interrupting the flow of DC current through the primary winding of the transformer such that a varying current results in the primary winding of the transformer; and

a heat sink, the at least one switch being mounted in both electrical connection and thermal conduction with the heat sink at a first location for dissipating thermal energy generated by the at least one switch, the primary winding of the transformer being electrically connected and in thermal conduction at a second location of the heat sink that is spatially removed from the first location such that the heat sink significantly dissipates heat generated by the at least one switch and heat generated at the connection between the primary winding and the heat sink.

16. The inverter of claim 15, wherein the primary winding of the transformer is thermally coupled to the second coupling location on the heat sink such that heat from the transformer is primarily dissipated by thermal conduction.

17. The inverter of claim 15, wherein the heat sink has opposite ends, the first and second locations being approximately on opposite ends of the heat sink.

18. The inverter of claim 15, wherein the heat sink comprises a a plurality of substantially parallel spaced-apart cooling fills, a substantial percentage of the cooling-fins being located between the first location and the second location.

19. The inverter of claim 15, wherein the transformer, the at least one switch, and the heat sink are designed with sufficient power capability to be able to convert at least an approximately 12 volt, 100-amp DC current into an approximately 120 volt AC output.