Isolation of particular fault conditions in an electric machine assembly

• US 10,355,634 B1
• Filed: 06/12/2018
• Issued: 07/16/2019
• Est. Priority Date: 06/12/2018
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: Zhang, Jiyu, Salman, Mutasim A.
• Primary Examiner(s): Santana, Eduardo Colon
• Assistant Examiner(s): Agared, Gabriel
• Application Number:
  US16/005,775
• Time in Patent Office: 399 Days
• Field of Search: 318490
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 2710/083 Torque
• CPC Class Codes: G01R 31/346 Testing of armature or field windings
• CPC Class Codes: G01R 31/50 Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections testing of sparking plugs H01T13/58
• CPC Class Codes: H02P 21/13 Observer control, e.g. using Luenberger observers or Kalman filters
• CPC Class Codes: H02P 21/14 Estimation or adaptation of machine parameters, e.g. flux, current or voltage
• CPC Class Codes: H02P 29/024 Detecting a fault condition, e.g. short circuit, locked rotor, open circuit or loss of load

Abstract

An electric machine assembly having an electric machine and a controller-based method for isolating a particular fault condition in the electric machine. A plurality of current sensors is configured to output respective measured currents in respective phases of the electric machine. A position sensor is configured to output a rotor position of the electric machine. A controller is configured to group the respective measured currents into respective combinations of two. The controller is configured to calculate respective residual factors (R_i), and a global residual factor (G) based on the respective residual factors (R_i). Responsive to at least three of the global residual factor (G) and the respective residual factors (R_i) exceeding respective calibrated error thresholds, the controller is configured to identify a particular fault condition from among a plurality of possible fault conditions and execute a control action with respect to the electric machine.

Claims

1. An electric machine assembly comprising:

an electric machine including a rotor and a stator;

a plurality of current sensors in communication with the electric machine and configured to output respective measured currents in respective phases of the electric machine;

a position sensor configured to output a rotor position of the electric machine;

a controller in communication with the electric machine and having a processor and tangible, non-transitory memory on which instructions are recorded for executing a method of isolating a particular fault condition from a plurality of possible fault conditions, execution of the instructions by the processor causing the controller to;

group the respective measured currents into respective combinations of two such that each of the respective measured currents is in a respective pair with another of the respective measured currents;

calculate respective residual factors (R_i) for the respective combinations based in part on the rotor position and the respective measured currents;

calculate a global residual factor (G) based on the respective residual factors (R_i);

responsive to at least three of the global residual factor (G) and the respective residual factors (R_i) exceeding respective calibrated error thresholds, identify the particular fault condition from among the plurality of possible fault conditions; and

execute a control action with respect to the electric machine, including recording a diagnostic code indicative of the particular fault condition.

2. The assembly of claim 1, wherein calculating the respective residual factors (R_i) for the respective combinations includes:

calculating a respective estimated voltage (V_i) for the respective combinations based in part on the rotor position and the respective measured currents; and

obtaining the respective residual factors (R_i) by subtracting the respective estimated voltage (V_i) from a desired voltage (v*).

3. The assembly of claim 1, wherein:

the respective residual factors include a first residual factor (R₁), a second residual factor (R₂) and a third residual factor (R₃);

the respective measured currents include a first measured current (i_A), a second measured current (i_B) and a third measured current (i_C);

the controller is configured to calculate a first parameter (P₀) based on a plurality of input factors; and

wherein the global residual factor (G) is defined as a square root of ((R₁−

R₂)²+(R₂−

R₃)²+(R₁−

R₃)²).

4. The assembly of claim 3, wherein identifying the particular fault condition from among the plurality of possible fault conditions includes:

diagnosing a motor fault condition when;

the first residual factor (R₁), the second residual factor (R₂), the third residual factor (R₃) and the global residual factor (G) are above the respective calibrated error thresholds; and

the first parameter (P₀) is less than a predetermined parameter threshold (H₀).

5. The assembly of claim 3, wherein identifying the particular fault condition from among a plurality of possible fault conditions includes:

diagnosing a first current sensor fault condition when the global residual factor (G), the first residual factor (R₁) and the third residual factor (R₃) are above the respective calibrated error thresholds;

diagnosing a second current sensor fault condition when the global residual factor (G), the first residual factor (R₁) and the second residual factor (R₂) are above the respective calibrated error thresholds; and

diagnosing a third current sensor fault condition when the global residual factor (G), the second residual factor (R₂) and the third residual factor (R₃) are above the respective calibrated error thresholds.

6. The assembly of claim 3, wherein identifying the particular fault condition from among a plurality of possible fault conditions includes:

diagnosing a resolver bias fault condition when the first residual factor (R₁), the second residual factor (R₂), the third residual factor (R₃) are above the respective calibrated error thresholds and the first parameter (P₀) is less than a predetermined parameter threshold (H₀); and

diagnosing a resolver non-bias fault condition when the first residual factor (R₁), the second residual factor (R₂), the third residual factor (R₃) and the first parameter (P₀) is at or above the predetermined parameter threshold (H₀).

7. The assembly of claim 3, wherein obtaining the first residual factor (R₁) includes:

obtain a first estimated current in a dq reference frame based on the rotor position, the first measured current (i_A) and the second measured current (i_B);

obtain a first estimated voltage in the dq reference frame based in part on the first estimated current; and

calculate the first residual factor (R₁) as an absolute value of a difference between a desired voltage and the first estimated voltage.

8. The assembly of claim 3, wherein obtaining the second residual factor (R₂) includes:

obtain a second estimated current in a dq reference frame based on the rotor position, the second measured current (i_B) and the third measured current (i_C);

obtain a second estimated voltage in the dq reference frame based in part on the second estimated current; and

calculate the second residual factor (R₂) as an absolute value of a difference between a desired voltage (v*) and the second estimated voltage.

9. The assembly of claim 3, wherein obtaining the third residual factor (R₃) includes:

obtain a third estimated current in a dq reference frame based on the rotor position, the third measured current (i_C) and the first measured current (i_A);

obtain a third estimated voltage in the dq reference frame based in part on the third estimated current; and

calculate the third residual factor (R₃) as an absolute value of a difference between a desired voltage and the third estimated voltage.

10. The assembly of claim 3, further comprising:

a transmission operatively connected to the electric machine and defining a gearbox ratio (η

);

at least one wheel operatively connected to the electric machine and having a wheel speed measurement (ω

); and

wherein the first parameter (P₀) is based on a rate of change in time (t) of the rotor position (θ

), a number of pole pairs (ρ

) in the electric machine, the gearbox ratio (η

) and the wheel speed measurement (ω

), the first parameter (P₀) being calculated as an absolute value of

11. A method of isolating a particular fault condition from a plurality of possible fault conditions in an electric machine assembly, the assembly having an electric machine with a rotor and a stator, a plurality of current sensors configured to output respective measured currents in respective phases of the electric machine, a position sensor configured to output a rotor position of the electric machine, a controller having a processor and tangible, non-transitory memory on which instructions are recorded, the method comprising:

receiving and grouping the respective measured currents into respective combinations of two such that each of the respective measured currents is in a respective pair with another of the respective measured currents, via the controller;

calculating respective residual factors (R_i) for the respective combinations based in part on the rotor position and the respective measured currents, via the controller;

calculating a global residual factor (G) based on the respective residual factors (R_i), via the controller;

responsive to at least three of the global residual factor (G) and the respective residual factors (R_i) exceeding respective calibrated error thresholds, identifying the particular fault condition from among the plurality of possible fault conditions, via the controller; and

executing a control action with respect to the electric machine, including recording a diagnostic code indicative of the particular fault condition.

12. The method of claim 11, wherein calculating the respective residual factors (R_i) for the respective combinations includes:

calculating a respective estimated voltage (V_i) for the respective combinations based in part on the rotor position and the respective measured currents; and

obtaining the respective residual factors (R_i) by subtracting the respective estimated voltage (V_i) from a desired voltage (v*).

13. The method of claim 11, wherein:

the respective measured currents include a first measured current (i_A), a second measured current (i_B) and a third measured current (i_C);

calculating the respective residual factors includes calculating a first residual factor (R₁), a second residual factor (R₂) and a third residual factor (R₃); and

the method further includes calculating a first parameter (P₀) based on a plurality of input factors, and calculating the global residual factor (G) as a square root of ((R₁−

R₂)²+(R₂−

R₃)²+(R₁−

R₃)²).

14. The method of claim 13, wherein identifying the particular fault condition from among the plurality of possible fault conditions includes:

diagnosing a motor fault condition when;

the first residual factor (R₁), the second residual factor (R₂), the third residual factor (R₃) and the global residual factor (G) are above the respective calibrated error thresholds; and

the first parameter (P₀) is less than a predetermined parameter threshold (H₀).

15. The method of claim 13, wherein identifying the particular fault condition from among the plurality of possible fault conditions includes:

diagnosing a first current sensor fault condition when the global residual factor (G), the first residual factor (R₁) and the third residual factor (R₃) are above the respective calibrated error thresholds;

diagnosing a second current sensor fault condition when the global residual factor (G), the first residual factor (R₁) and the second residual factor (R₂) are above the respective calibrated error thresholds; and

diagnosing a third current sensor fault condition when the global residual factor (G), the second residual factor (R₂) and the third residual factor (R₃) are above the respective calibrated error thresholds.

16. The method of claim 13, wherein identifying the particular fault condition from among the plurality of possible fault conditions includes:

diagnosing a resolver bias fault condition when the first residual factor (R₁), the second residual factor (R₂), the third residual factor (R₃) are above the respective calibrated error thresholds and the first parameter (P₀) is less than a predetermined parameter threshold (H₀); and

diagnosing a resolver non-bias fault condition when the first residual factor (R₁), the second residual factor (R₂), the third residual factor (R₃) and the first parameter (P₀) is at or above the predetermined parameter threshold (H₀).

17. The method of claim 13, wherein the assembly includes a transmission defining a gearbox ratio (η

) and at least one wheel having a wheel speed measurement (ω

), the method further comprising;

calculating the first parameter (P₀) based on a rate of change in time (t) of the rotor position (θ

), a number of pole pairs (ρ

) in the electric machine, the gearbox ratio (η

) and the wheel speed measurement (ω

), the first parameter (P₀) being calculated as an absolute value of