Method and device for current monitoring in a current supply system

• US 6,489,693 B1
• Filed: 02/10/2000
• Issued: 12/03/2002
• Est. Priority Date: 02/15/1999
• Status: Expired due to Term

• Current Assignee: Isabellenhuette Heusler GmbH & Co. KG
• Original Assignee: Isabellenhuette Heusler GmbH & Co. KG
• Inventors: Hetzler, Ullrich
• Primary Examiner(s): FLEMING, FRITZ M
• Application Number:
  US09/501,438
• Time in Patent Office: 1,027 Days
• Field of Search: 307/9.1, 307/10.1, 307/38-41
• US Class Current: 307/10.1
• CPC Class Codes: G01R 19/0092 measuring current only all subgroups of G01R19/00 take precedence
• CPC Class Codes: G01R 31/007 using microprocessors or computers

Abstract

In a power supply system supplying several loads (10, 11, 12) using a joint power bus (LB) and connecting electronic control units (μC) with each other and the loads by means of a control bus (CAN) for digital information and control data, a measuring resistor (21) connected in series with the power bus measures the total current of the loads connected, measurement information is transferred on the control bus (CAN), and the differential current resulting from a switching process is evaluated by the control system. The measuring resistor (21) comprising a metal alloy is integrated with a semiconductor chip with heat conducting connection directly or via a printed circuit board (PCB), which contains the whole evaluation and transmission electronics, into a small, compact current measuring module.

Claims

1. Method for current monitoring in a current supply system in which current is supplied from a power source to a plurality of switchable loads (10, 11, 12) each of a different resistance, via a power bus (LB) common to each of said loads (10, 11, 12), and in which a control bus (CAN) for digital information and control data is connected to electronic control means (16) and connects a plurality of electronic control units (μ

C1, μ

C2 . . . μ

Cn) to each other and to said loads (10, 11, 12), the method comprising the steps of;

providing a current measuring module (20) comprising a sensor resistor (21) and a semiconductor element (23) generating digital measuring data corresponding to the current through said resistor (21);

said module (20) measuring the total current of all of said loads (10, 11, 12) connected to the power bus (LB), said resistor (21) being connected to the power bus in line between said power source and said plurality of loads;

the digital measuring data generated by said module (20) and corresponding to said measured total current being applied to said electronic control means (16) via said control bus (CAN);

and monitoring the function of one of said switchable loads (10, 11, 12) by;

applying the digital total current measuring data to said electronic control means (16) before said one load is switched;

applying the new digital total current measuring data to said electronic control means after switching of said one load; and

said electronic control means (16)

determining the difference between the two values of the digital total current measuring data provided before and after said switching;

evaluating said total current difference by comparing it with stored reference data, and

generating a signal in case of abnormal deviation of the current difference from the reference data.

2. Method according to claim 1 wherein said sensor resistor is made of a copper-based alloy.

3. Method according to claim 1, characterized in that said electronic control means for evaluation of the differential current compares this difference with a stored prescribed setpoint or setting range and in case of abnormal deviation creates a warning signal.

4. Method according to claims 1 or 2, characterized in that a metallic measuring resistor is used as current sensor resistor (21), whose power connections are electrically connected into said power bus (LB) in series and whose analog measuring voltage generated at its voltage connections is converted into digital measuring signals by a semiconductor chip (23) and is integrated with said resistor in a common casing as a current measuring module (20), said measuring signals being applied to said control bus (CAN).

5. Method according to claim 4, characterized in that a resistor (21) with a plate-shaped element (31) made of a resistor alloy is used as a current sensor, on whose edges plate-shaped power connection parts (32) are welded.

6. Method according to claim 1 or 2 characterized in that said current sensor resistor (21) is calibrated by external digital data which are gained by measurement of said current sensor resistor'"'"'s actual resistance value and stored in a semiconductor memory connected to said resistor and which during current monitoring operation control a measuring circuit connected to said resistor for generation of corrected measuring data.

7. Method according to claim 6, characterized in that the external calibration data is transmitted to the semiconductor memory via the control bus (CAN).

8. Method for current monitoring in a current supply system in which current is supplied from a battery (B) to a plurality of switchable loads (10, 11, 12) each of a different resistance, via power bus (LB) common to each of said loads (10, 11, 12), and in which a control bus (CAN) for digital information and control data is connected to electronic control means (16) and connects a plurality of electronic control units (μ

C1, μ

C2 . . . μ

Cn) to each other and to said loads (10, 11, 12), the method comprising the steps of;

providing a current measuring module (10) comprising a sensor resistor (21) and a semiconductor element (23) generating digital measuring data corresponding to the current through said resistor (21);

said module (20) measuring the total current from said battery (B) to all of said loads (10, 11, 12) connected to the power bus (LB), said resistor (21) being connected to the power bus in line between said battery and said plurality of loads;

said module (20) also measuring a charging current supplied to the battery (B) and generating digital measuring data corresponding to the charging current;

the digital measuring data generated by said module (20) and corresponding to the measured battery current being applied to said electronic control means (16) via said control bus (CAN); and

said electronic control means (16) monitoring the digital battery current data and producing signals for limiting the battery current to a predetermined admissible maximum value in response to said battery current data.

9. A device for current monitoring for use in a current supply system in which current is supplied to a plurality of loads (10, 11, 12) via a power bus (LB) common to said loads and a control bus (CAN) for digital control data connects a plurality of electronic control units (μ

C1, μ

C2 . . . μ

Cn) among each other and with said loads, said device comprising;

a measuring resistor (30) comprising a resistance element (31) made of a metal alloy and having power connection parts (32) and voltage connections (49), and

a semiconductor element (23) electrically connected to said voltage connection (49) of said resistor (30), for generation of digital measuring data corresponding to the current through the resistance element (31),

said semiconductor element (23) being situated on a flat surface of said resistor (30) with a heat coupling connection with said resistance element (31).

10. Device according to claim 9, characterized in that said semiconductor element (23) contains a temperature sensor, and a temperature compensation circuit within said semiconductor element (23) corrects the current measuring signals in response to the temperature of the resistance element (31) measured by said temperature sensor.

11. A device according to claim 9 having a plate-shaped resistance element including main surfaces and opposite edges, characterized in that said semiconductor element (23) is located on one of said main surfaces of said plate-shaped resistance element (31) consisting of a resistance alloy, to which said opposite edges plate-shaped power connection parts (32) are welded.

12. A device according to claim 9 in which said resistance element (31) includes a metal surface, characterized in that said semiconductor element (23) is adhered directly onto said metal surface of said resistance element (31) and is connected to said power connection parts (32) by bonding wires (49).

13. A device according to claim 9 characterized in that said semiconductor element (23) is mounted on one side of a PCB (36), which is situated at its opposite side on said metal surface of said resistor (30) and is soldered to said power connection parts (32).

14. A device according to claim 9 characterized in that said semiconductor element (23) contains an A/D converter, an amplifier circuit, and/or a microprocessor for said measuring signals of said resistor (30).

15. A device according to claim 9 characterized in that a plug-in connector (41) is provided for connection to said control bus (CAN).

16. A device according to claim 15, characterized in that said plug-in connector is a component adhered to said metal surface of said resistor (30).

17. A device according to claim 15, characterized in that said plug-in connector (41) is a component located on said PCB (36) between said resistor (30) and said semiconductor element (23) and electrically connected to said semiconductor element (23).

18. System for current monitoring in a current supply system in which current is supplied from a power source to a plurality of switchable loads (10, 11, 12), each of a different resistance, via a power bus (LB) common to each of said loads (10, 11, 12), and in which a control bus (CAN) for digital information and control data is connected to electronic control means (16) and connects a plurality of electronic control units (μ

C1, μ

C2 . . . μ

Cn) among each other and to said loads (10, 11, 12),

the system comprising a current measuring module (20) including a sensor resistor (21) and a semiconductor element (23) generating digital measuring data corresponding to the current through said resistor (21),

said resistor (21) being connected to said power bus (LB) in line between said power source and said plurality of loads (10, 11, 12) so that said module (20) measures the total current of all of said loads connected to the power bus,

the digital measuring data generated by said module (20) and corresponding to said measured total current being applied to said electronic control means (16) via said control bus (CAN);

and the function of one of said switchable loads (10, 11, 12) being monitored by;

applying the digital total current measuring data to said electronic control means (16) before said one load is switched;

applying the new digital total current measuring data to said electronic control means after switching of said one load; and

said electronic control means (16)

determining the difference between the two values of the digital total current measuring data provided before and after said switching;

evaluating said total current difference by comparing it with stored reference data, and

generating a signal in case of abnormal deviation of the current difference from the reference data.

19. System for current monitoring in a current supply system in which current is supplied from a battery (B) to a plurality of switchable loads (10, 11, 12), each of a different resistance, via a power bus (LB) common to each of said loads (10, 11, 12), and in which a control bus (CAN) for digital information and control data is connected to electric control means (16) and connects a plurality for electronic control units (μ

C1, μ

C2 . . . μ

Cn) to each other and to said loads (10, 11, 12),

the system comprising a current measuring module (20) including a sensor resistor (21) and a semiconductor element (23) generating digital measuring data corresponding to the current through said resistor (21),

said resistor (21) being connected to said power bus (LB) in line between said battery (B) and said plurality of loads (10, 11, 12) so that said module (20) measures the total current from said battery (B) to all of said loads (10, 11, 12) connected to the power bus (LB),

the digital measuring data generated by said module (20) and corresponding to the measured battery current being applied to said electronic control means (16) via said control bus (CAN); and

said electronic control means (16) monitoring the digital battery current data and producing signals for limiting the battery current to a predetermined admissible maximum value in response to said battery current data.