Droop compensation for device under test spectroscopy

Patent metadata

Field	Value
Publication number	US-11768250-B2
Application number	US-202117463186-A
Country	US
Kind code	B2
Filing date	Aug 31, 2021
Priority date	Feb 12, 2021
Publication date	Sep 26, 2023
Grant date	Sep 26, 2023

Abstract

A method includes determining a droop component of a measured parameter of a device under test (DUT). The measured parameter is responsive to an excitation signal having a frequency component, and the droop component is determined responsive to a first value of the parameter at a first time and a second value of the parameter at a second time. The parameter at the first time has a first phase value, and the parameter at the second time has a second phase value. The first phase value is equal to the second phase value. The method also includes correcting a frequency domain representation of the parameter by applying the droop component at a frequency of the representation of the parameter corresponding to the frequency component of the excitation signal.

First claim

What is claimed is:

1. A method, comprising:
determining a frequency domain representation of a parameter of a device under test (DUT), the parameter having multiple cycles;
determining a frequency domain representation of a droop component of the parameter based on the parameter, in which the droop component represents a rate of change of the parameter across one or more cycles of the multiple cycles; and
generating an adjusted parameter of the DUT based on combining the respective frequency domain representations of the parameter and the droop component.

2. The method of claim 1 , further comprising:
determining a frequency domain representation of an excitation signal, in which the parameter represents a response of the DUT to the excitation signal:
based on the frequency domain representation of the excitation signal, determining a first frequency component of the parameter and a second frequency component of the droop component at a particular frequency, and
wherein generating the adjusted parameter of the DUT based on combining the respective frequency domain representations of the parameter and the droop component includes generating a third frequency component of the adjusted parameter at the particular frequency by combining the first and second frequency components.

3. The method of claim 2 , wherein based on the frequency domain representation of the excitation signal, determining the first frequency component of the parameter and the second frequency component of the droop component at a particular frequency includes:
determining, from the frequency domain representation of the excitation signal, a particular discrete Fourier transform frequency bin; and
determining, from the frequency domain representation of the parameter, the first frequency component associated with the particular discrete Fourier transform frequency bin; and
determining, from the frequency domain representation of the droop component, the second frequency component associated with the particular discrete Fourier transform frequency bin.

4. The method of claim 2 , wherein the determining the droop component of the parameter based on the parameter includes:
determining, from a time domain representation of the parameter, a first value associated with a first time:
determining, from the time domain representation of the parameter, a second value associated with a second time; and
determining the frequency domain representation of the droop component based on the first and second values.

5. The method of claim 4 , wherein determining the frequency domain representation of the droop component includes determining a slope based on the first value and the second value, and wherein an amount of time between the first time and the second time is equal to an integer multiple of a period of the excitation signal.

6. The method of claim 5 , wherein the slope is determined based on a least-square line fitting computation.

7. The method of claim 1 , wherein the DUT includes a battery cell or a group of battery cells.

8. The method of claim 2 , wherein the excitation signal includes a at least one of a current signal or a voltage signal, and wherein the parameter includes at least one of: a current conducted by the DUT, a voltage across the DUT, or an impedance of the DUT.

9. The method of claim 2 , further comprising:
receiving samples of a current through the DUT or a voltage across the DUT; and
identifying subsets of the samples in different windows; and
determining the parameter based on averaging the subsets of the samples.

10. A system, comprising:
a parameter determination circuit having a device input and a parameter output, the device input coupled to a device under test (DUT), and the parameter determination circuit configured to provide a frequency domain representation of a parameter of the DUT at the parameter output, the parameter having multiple cycles;
a droop determination circuit having a first parameter input and a droop output, the first parameter input coupled to the parameter output, and the droop determination circuit configured to provide a frequency domain representation of a droop component of the parameter at the droop output responsive to the parameter, in which the droop component represents a rate of change of the parameter across one or more cycles of the multiple cycles; and
a parameter adjustment circuit having a second parameter input, a droop input, and an adjusted parameter output, the second parameter input coupled to the parameter output, the droop input coupled to the droop output, and the parameter adjust circuit configured to provide an adjusted parameter of the DUT at the adjusted parameter output based on combining the respective frequency domain representations of the parameter and the droop component.

11. The system of claim 10 , wherein:
the parameter determination circuit has a frequency output and configured to:
determine a frequency domain representation of an excitation signal, in which the parameter represents a response of the DUT to the excitation signal;
based on the frequency domain representation of the excitation signal, provide a first frequency component of the parameter at a particular frequency at the parameter output: and
provide a signal representing the particular frequency at the frequency output;

the droop determination circuit has a frequency input coupled to the frequency output and configured to provide a second frequency component of the droop component at the particular frequency; and
the parameter adjustment circuit is configured to provide the adjusted parameter based generating a third frequency component of the adjusted parameter at the particular frequency by combining the first and second frequency components.

12. The system of claim 11 , wherein the signal representing the particular frequency represents a particular discrete Fourier transform frequency bin.

13. The system of claim 11 , wherein the droop determination circuit is configured to:
determine, from a time domain representation of the parameter, a first value associated with a first time:
determine, from the time domain representation of the parameter, a second value associated with a second time; and
determine the frequency domain representation of the droop component based on the first and second values.

14. The system of claim 13 , wherein the droop determination circuit is configured to determine a slope based on the first value and the second value, and wherein an amount of time between the first time and the second time is equal to an integer multiple of a period of the excitation signal.

15. The system of claim 14 , wherein the droop determination circuit is configured to determine the slope based on a least-square line fitting computation.

16. The system of claim 11 , wherein the DUT includes a battery cell or a group of battery cells.

17. The system of claim 16 , wherein the excitation signal includes at least one of a current signal or a voltage signal, and wherein the parameter includes at least one of: a current conducted by the DUT, a voltage across the DUT, or an impedance of the DUT.

18. A non-transitory computer-readable medium comprising instructions that, when executed by a processor, cause the processor to:
determine a frequency domain representation of a parameter of a device under test (DUT), the parameter having multiple cycles;
determine a frequency domain representation of a droop component of the parameter based on the parameter, in which the droop component represents a rate of change of the

Assignees

• Texas Instruments Inc

Inventors

• Sestok Iv Charles Kasimer
• Magee David Patrick

Classifications

• G01R31/389 Primary

  Measuring internal impedance, internal conductance or related variables · CPC title

• G01R31/3835

  involving only voltage measurements · CPC title

• G01R31/396

  Acquisition or processing of data for testing or for monitoring individual cells or groups of cells within a battery · CPC title

• G01R31/3842 Primary

  combining voltage and current measurements · CPC title

• G01R31/367

  Software therefor, e.g. for battery testing using modelling or look-up tables · CPC title