ELECTRIC HEATER FOR A MOTOR VEHICLE

• US 20010013512A1
• Filed: 06/09/1999
• Published: 08/16/2001
• Est. Priority Date: 07/31/1997
• Status: Active Grant

• Current Assignee: GKR Gesellschaft Fur Fahrzeugklimaregelung mbH
• Original Assignee: GKR Gesellschaft Fur Fahrzeugklimaregelung mbH
• Inventors: EISENHARDT, HARALD, FALLIANO, ROLF
• Granted Patent: US 6,348,672 B2
• Time in Patent Office: Days
• US Class Current: 219/202
• CPC Class Codes: B60H 1/2215 the heat being derived from electric heaters
• CPC Class Codes: B60H 2001/2271 Heat exchangers, burners, ignition devices
• CPC Class Codes: H01L 25/162 the devices being mounted on two or more different substrates
• 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: H01L 2924/3011 Impedance
• CPC Class Codes: H05B 1/0205 using a fusible material
• CPC Class Codes: H05B 1/0236 for vehicles
• CPC Class Codes: H05B 3/14 the material being non-metallic

Abstract

An electric heater for a motor vehicle uses heat generated by power semiconductors as the heat source. The heat output by the power semiconductors is used directly for heating. The power semiconductors are regulated by circuit regulators to be able to adjust the heating power continuously. In addition, switching devices are provided which interrupt or shut down the respective branch circuits individually in the event of short circuits in the power semiconductors.

Claims

1. An electric heater for a motor vehicle, using heat generated by power semiconductors as the heat source, characterized in that

several branch circuits (Z1, Z2, Zn), each with one power semiconductor (FET1, FET2, FETn) operated in high power loss operation, are connected in parallel for generation of heat.

3. The electric heater according to

claim 1

or

2

, characterized in that

a switching device (FUSE1, FUSE2, FUSEn) which responds to overload is connected in series to the power semiconductor (FET1, FET2, FETn) in each branch circuit (Z1, Z2, Zn).

4. The electric heater according to

claim 1

or

3

, characterized in that

the power output by the power semiconductors (FET1, FET2, FETn) can be regulated individually by a common predetermined setpoint (Isoll) and by actual values (Ist1, Ist2, . . . , Istn) derived from the power semiconductors (FET1, FET2, . . . , FETn).

6. The electric heater according to one of claims 1 through 5,

characterized in that

the power semiconductors (FET1, FET2, . . . , FETn;

FET11, FET12, FET21, FET22, . . . FETn1, FETn2) are operated in the short circuit.

7. The electric heater according to one of claims 1 through 6,

characterized in that

the branch circuits (Z1, Z2, . . . , Zn) supply power at the output to a low-resistance series resistor as a load impedance.

8. The electric heater according to one of claims 1 through 7,

characterized in that

the switching devices (FUSE1, FUSE2, . . . , FUSEn) are designed as a printed conductor part of the branch circuits (Z1, Z2, . . . , Zn) which burn out in the event of a fault at the elevated current occurring in the respective branch circuit (Z1, Z2, . . . , Zn).

9. The electric heater according to one of claims 1 through 7,

characterized in that

the switching devices (FUSE1, FUSE2, FUSEn) are looped as shunts into branch circuits (Z1, Z2, Zn) which burn out in the event of a fault at the elevated current occurring in the respective branch circuit (Z1, Z2, . . . , Zn).

10. The electric heater according to one of claims 1 through 7,

characterized in that

the connecting wires of the power semiconductors (FET1, FET2, FETn;

FET11, FET12, FET21, FET22, FETn1, FETn2) are used as switching devices (FUSE1, FUSE2, FUSEn) which burn out in the event of a fault at the elevated current occurring in the respective branch circuit (Z1, Z2, Zn).

12. The electric heater according to one of claims 1 through 11,

characterized in that

it is designed as a heater module, with the power semiconductors (FET1, FET2, . . . , FETn;

FET11, FET12;

FET21, FET22;

FETn1, FETn2) mounted in thermal contact on a cooling body.

13. The electric heater according to

claim 12

,

characterized in that

the power semiconductors (FET1, FET2, . . . , FETn;

FET11, FET12, FET21, FET22, . . . , FETn1, FETn2) and/or the cooling body are monitored by temperature sensors to detect whether a predetermined maximum temperature is exceeded, and

in that the output signals of the temperature sensor(s) reduce the power output of the respective power semiconductors or all the power semiconductors or switch them to a disconnect status.

14. The electric heater according to

claim 13

,

characterized in that

the temperature sensors are integrated into the power semiconductors (FET1, FET2, . . . , FETn;

FET11, FET12, FET21, FET22, . . . , FETn1, FETn2).

2. An electric heater for a motor vehicle, using heat generated by power semiconductors as the heat source, characterized in that

several branch circuits (Z1, Z2, Zn), each with two series-connected power semiconductors (FET11, FET12;

FET21, FET22;

FETn1, FETn2) operated in high power loss operation, are connected in parallel for generation of heat.

5. The electric heater according to

claim 2

or

3

, characterized in that

the powers output by the respective first power semiconductors (FET11, FET21, FETn1) of the branch circuits (Z1, Z2, Zn) can be regulated individually by a common predetermined setpoint,(Isoll) and by actual values (Ist11, Ist21, . . . , Istn1) derived at these power semiconductors, and the powers output by the respective second power semiconductors (FET12, FET22, . . . , FETn2) can be regulated individually by a fixed predetermined control voltage (ust) and by actual values (Ist12, Ist2, . . . , Istn2) derived at these power semiconductors.

11. The electric heater according to one of claims 2, 3 and 5 through 7,

characterized in that

in the event of a short circuit in one of the two power semiconductors (FET11 or FET12;

FET21 or FET22;

FETn1 or FETn2) connected in series in a branch circuit (Z1, Z2, Zn), an additional control signal can be derived from the defective branch circuit (Z1, Z2, Zn) to reduce the power output by the respective second power semiconductor (FET12 or FET11;

FET22 or FET21;

FETn2 or FETn1) or switch it to a disconnect status.