Increasing current and voltage sensor accuracy and resolution in electric and hybrid electric vehicles

• US 7,136,763 B2
• Filed: 06/17/2003
• Issued: 11/14/2006
• Est. Priority Date: 06/17/2003
• Status: Expired due to Fees

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: General Motors Corporation (General Motors Company)
• Inventors: Tate, Edward D. Jr.
• Primary Examiner(s): Barlow, John
• Assistant Examiner(s): Lau, Tung S.
• Application Number:
  US10/463,110
• Publication Number:
  US 20040260491A1
• Time in Patent Office: 1,246 Days
• Field of Search: 702/64, 702/35, 324/322, 324/772, 324/500, 324/76.11, 700/293, 700/291, 600/323, 340/538, 340/660, 177/25, 438/57, 438/1, 345/156, 607/2, 318/432, 318/701, 257/292, 348/308, 348/302, 280/461, 359/889, 356/418
• US Class Current: 702/64
• CPC Class Codes: B60L 58/20 having different nominal voltages
• CPC Class Codes: H02M 1/0009 Devices or circuits for detecting current in a converter
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

A method for estimating an electrical measurement, such as a current or a voltage, comprises generating an analog electrical measurement signal using a sensor. An analog filter filters the analog electrical measurement signal. An A/D converter samples the analog signal and generates a digital electrical measurement signal. A matrix is formed based on the characteristics of the analog filter. An estimated actual current or voltage is calculated based on a relationship between the digital signal and the matrix.

Claims

1. A method for estimating current in an electrical system, comprising:

generating an analog current signal using a current sensor;

filtering the analog current signal using an analog filter;

generating a digital current signal by sampling the analog current signal using an A/D converter;

forming a two dimensional matrix based on an impulse response of the analog filter and predetermined characteristics of the analog filter, the predetermined characteristics comprising at least one of linearity, saturation, and damping;

defining a relationship between the digital current signal and the two dimensional matrix; and

calculating and storing an estimated actual current based on the relationship;

wherein the current sensor is one of a Hall effect sensor and at least one sense resistor.

2. The method according to claim 1 further comprising:

drawing current through the current sensor using an inverter; and

varying the current drawn through the current sensor using the inverter, wherein the inverter varies the current drawn in sync with a trigger.

3. The method according to claim 2 wherein the inverter communicates with a power source.

4. The method according to claim 2 further comprising communicating the trigger to the inverter at predetermined intervals.

5. The method according to claim 1 wherein the analog filter is a low-pass filter.

6. The method according to claim 1 wherein the current sensor communicates with at least one of a fuel cell system and a supercapacitor system.

7. A method for estimating current in an electrical system, comprising:

generating an analog current signal using a current sensor;

filtering the analog current signal using an analog filter;

generating a digital current signal by sampling the analog current signal using an A/D converter;

forming a two dimensional matrix based on an impulse response of the analog filter and predetermined characteristics of the analog filter, the predetermined characteristics comprising at least one of linearity, saturation, and damping;

defining a relationship between the digital current signal and the two dimensional matrix; and

calculating and storing an estimated actual current based on the relationship;

wherein the current sensor communicates with at least one of a fuel cell system and a supercapacitor system.

8. The method according to claim 7 further comprising:

drawing current through the current sensor using an inverter; and

varying the current drawn through the current sensor using the inverter, wherein the inverter varies the current drawn in sync with a trigger.

9. The method according to claim 8 wherein the inverter communicates with a power source.

10. The method according to claim 8 further comprising communicating the trigger to the inverter at predetermined intervals.

11. The method according to claim 7 wherein the current sensor is one of a Hall effect sensor and at least one sense resistor.

12. The method according to claim 7 wherein the analog filter is a low-pass filter.

13. A method for estimating voltage in an electrical system, comprising:

generating an analog voltage signal using a voltage sensor;

filtering the analog voltage signal using an analog filter;

generating a digital voltage signal by sampling the analog voltage signal using an A/D converter;

forming a two dimensional matrix based on an impulse response of the analog filter and predetermined characteristics of the analog filter, the predetermined characteristics comprising at least one of linearity, saturation, and damping;

defining a relationship between the digital voltage signal and the two dimensional matrix; and

calculating and storing an estimated actual voltage based on the relationship;

wherein the voltage sensor communicates with at least one of a fuel cell system and a supercapacitor system.

14. The method according to claim 13 wherein generating an analog voltage signal includes generating a voltage measurement of a power source.

15. The method according to claim 14 wherein the power source is a battery.

16. The method according to claim 14 further comprising:

drawing power from power source with an inverter; and

varying the power drawn from the power source, wherein the inverter varies the power drawn synchronous to a trigger.

17. The method according to claim 16 wherein the A/D converter samples the analog voltage signal synchronous to a trigger.

18. The method according to claim 16 further comprising communicating the trigger to the inverter at predetermined intervals.

19. The method according to claim 13 wherein the analog filter is a low-pass filter.

20. A method for estimating an electrical measurement with a measurement algorithm comprising:

collecting measurement samples in a column vector;

forming a two dimensional matrix based on an impulse response of an analog filter and predetermined characteristics of the analog filter, the predetermined characteristics comprising at least one of linearity, saturation, and damping;

defining a relationship between the vector and the two dimensional matrix; and

estimating and storing an electrical measurement based on the relationship;

wherein estimating and storing the electrical measurement includes deriving the electrical measurement from the relationship using a least squares method.

21. The method according to claim 20 wherein forming the two dimensional matrix includes forming the two dimensional matrix according to a sampling rate of measurement samples, and a measurement sample.

22. The method according to claim 20 wherein defining the relationship includes forming the relationship according to the two dimensional matrix, a vector of electrical measurements, and noise, wherein the column vector is equal to the product of the two dimensional matrix and the vector of electrical measurements, adjusted by the noise.

23. The method according to claim 20 wherein the electrical measurement is a current.

24. The method according to claim 20 wherein the electrical measurement is a voltage.

25. The method according to claim 20 wherein collecting the measurement samples includes collecting the measurement samples from an A/D converter.

26. The method according to claim 20 further comprising changing a power setting at an inverter.

27. The method according to claim 26 wherein estimating the electrical measurement includes estimating the electrical measurement synchronous to changing the power setting.

28. An electrical measurement system comprising:

an electrical sensor that generates a first set of electrical measurements;

an analog filter that filters the first set of electrical measurements;

an A/D converter that generates electrical samples from the first set of electrical measurements;

a microprocessor that forms a two dimensional matrix based on an impulse response of the analog filter and predetermined characteristics of the analog filter, defines a relationship between the electrical samples and the two dimensional matrix, and calculates a second set of electrical measurements based on the relationship, wherein the predetermined characteristics comprise at least one of linearity, saturation, and damping;

a power source; and

an inverter that draws power from the power source.

wherein the power source is one of a battery, a fuel cell system, and a supercapacitor system.

29. The electrical measurement system according to claim 28 wherein the electrical sensor is a current sensor.

30. The electrical measurement system according to claim 28 wherein the electrical sensor is a voltage sensor.

31. The electrical measurement system according to claim 28 wherein the inverter varies the power drawn from the power source.

32. The electrical measurement system according to claim 31 wherein the inverter varies the power drawn synchronous to a trigger.

33. The electrical measurement system according to claim 32 wherein the A/D converter generates the electrical samples synchronous to the trigger.

34. The electrical measurement system according to claim 32 wherein the trigger executes periodically.

35. The electrical measurement system according to claim 28 wherein the filter is a low-pass filter.

36. The electrical measurement system according to claim 28 wherein the electrical sensor is a current sensor that is one of a hall effect sensor and at least one sense resistor.

37. An electrical measurement system comprising:

an electrical sensor that generates a first set of electrical measurements;

an analog filter that filters the first set of electrical measurements;

an A/D converter that generates electrical samples from the first set of electrical measurements;

a microprocessor that forms a two dimensional matrix based on an impulse response of the analog filter and predetermined characteristics of the analog filter, defines a relationship between the electrical samples and the two dimensional matrix, and calculates a second set of electrical measurements based on the relationship, wherein the predetermined characteristics comprise at least one of linearity, saturation, and damping;

wherein the electrical sensor is a current sensor that is one of a hall effect sensor and at least one sense resistor.

38. The electrical measurement system according to claim 37 wherein the filter is a low-pass filter.