# US 2014/0191697 A1 · Stator winding diagnostic systems and methods > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0191697 A1 - Document ID: US20140191697A1 - Status: Published application - Kind: A1 - Application number: 13/738,123 - Filed: 2013-01-10 - Published: 2014-07-10 - Earliest claimed: 2013-01-10 - Assignees: GM Global Technology Operations LLC - Applicants: GM Global Technology Operations LLC - Inventors: XIAOFENG MAO; LEI HAO - Web page: https://patentgrep.com/patent/US20140191697A1 ## CPC - H02P 29/0241: {the fault being an overvoltage} - G01R 31/346: {Testing of armature or field windings} - H02P: CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) ## Abstract Systems and methods are provided for diagnosing stator windings in an electric motor. An exemplary method for diagnosing stator windings in an electric motor involves determining an input energy imbalance across phases of the stator windings for an electrical period of the electric motor and identifying a fault condition when the input energy imbalance is greater than a first threshold value. In some embodiments, an input energy ratio across phases of the stator windings is also determined for the electrical period, wherein the fault condition is identified as a phase-to-phase short circuit fault condition when the input energy ratio is greater than a second threshold value and the input energy imbalance is greater than the first threshold value, or alternatively, as an in-phase short circuit fault condition when the input energy ratio is less than the second threshold value. ## Claims ### Claim 1 A method for diagnosing stator windings in an electric motor, the method comprising: determining an input energy imbalance across phases of the stator windings for an electrical period of the electric motor; and identifying a fault condition when the input energy imbalance is greater than a threshold value. ### Claim 2 (depends on 1) The method of claim 1, further comprising determining an input energy ratio across the phases of the stator windings for the electrical period, wherein identifying the fault condition further comprises identifying a phase-to-phase short circuit fault condition when the input energy ratio is greater than a second threshold value and the input energy imbalance is greater than the threshold value. ### Claim 3 (depends on 1) The method of claim 1, wherein determining the input energy imbalance further comprises determining a maximal input energy difference among respective pairs of phases of stator windings of the electric motor. ### Claim 4 (depends on 1) The method of claim 1, wherein determining the input energy imbalance further comprises determining an input energy difference between a first phase of stator windings and a second phase of stator windings. ### Claim 5 (depends on 4) The method of claim 4, further comprising determining an input energy ratio for the first phase with respect to the second phase for the electrical period when the input energy difference is greater than the threshold value, wherein identifying the fault condition further comprises identifying a phase-to-phase short circuit fault condition when the input energy ratio is greater than a second threshold value. ### Claim 6 (depends on 4) The method of claim 4, further comprising determining a ratio of a first phase input energy for the first phase with respect to a second phase input energy for the second phase, wherein identifying the fault condition comprises: identifying a phase-to-phase short circuit fault condition when the input energy difference is greater than the threshold value and the ratio is greater than a second threshold value; and identifying an in-phase short circuit fault condition when the input energy difference is greater than the threshold value and the ratio is less than the second threshold value. ### Claim 7 (depends on 1) The method of claim 1, wherein determining the input energy imbalance further comprises: determining a first phase input energy metric for a first phase of stator windings over the electrical period; determining a second phase input energy metric for a second phase of stator windings over the electrical period; and determining the input energy imbalance as a difference between the first phase input energy metric and the second phase input energy metric. ### Claim 8 (depends on 7) The method of claim 7, wherein: determining the first phase input energy metric further comprises accumulating a first plurality of instantaneous input power values for the first phase during the electrical period; and determining the second phase input energy metric further comprises accumulating a second plurality of instantaneous input power values for the second phase during the electrical period. ### Claim 9 (depends on 8) The method of claim 8, wherein accumulating the first plurality of instantaneous input power values further comprises: calculating a first instantaneous input power value for the first phase based on a first instantaneous voltage applied to the first phase and a first instantaneous current through the first phase at a first time during the electrical period; calculating a second instantaneous input power value for the first phase based on a second instantaneous voltage applied to the first phase and a second instantaneous current through the first phase at a second time during the electrical period; and adding the first instantaneous input power value and the second instantaneous input power value. ### Claim 10 (depends on 8) The method of claim 8, wherein accumulating the first plurality of instantaneous input power values further comprises: obtaining an instantaneous voltage applied to the first phase at a first time during the electrical period; obtaining an instantaneous current through the first phase at the first time during the electrical period; calculating an instantaneous input power value for the first phase based on the instantaneous voltage and the instantaneous current; and adding the instantaneous input power value to a preceding instantaneous input power value to obtain the first phase input energy metric. ### Claim 11 (depends on 1) The method of claim 1, further comprising: obtaining a first voltage command for a first phase of stator windings at a first time during the electrical period; obtaining a second voltage command for a second phase of stator windings at the first time; obtaining a first measured current through the first phase at the first time; and obtaining a second measured current through the second phase at the first time, wherein determining the input energy imbalance further comprises: determining a first phase input energy metric for the first phase based at least in part on the first voltage command and the first measured current; determining a second phase input energy metric for the second phase based at least in part on the second voltage command and the second measured current; and determining the input energy imbalance as a difference between the first phase input energy metric and the second phase input energy metric. ### Claim 12 A vehicle comprising: an electric motor having stator windings, each stator winding corresponding to a respective phase of the electric motor; an inverter module coupled to the stator windings to provide commanded voltages from an energy source to the stator windings of the electric motor in response to voltage commands corresponding to the phases of the electric motor; a plurality of current sensors coupled between the inverter module and the stator windings to obtain measured currents through the stator windings; and a control module coupled to the inverter module and the plurality of current sensors to: generate the voltage commands corresponding to the commanded voltages based on a difference between the measured currents and commanded currents; determine an input energy difference between phases of the electric motor based on the voltage commands and the measured currents; and identify a fault condition in the stator windings based on the input energy difference. ### Claim 13 (depends on 12) The vehicle of claim 12, wherein the input energy difference comprises a maximal input energy difference among the phases of the electric motor. ### Claim 14 (depends on 12) The vehicle of claim 12, wherein the control module identifies the fault condition when the input energy difference exceeds a first threshold value. ### Claim 15 (depends on 12) The vehicle of claim 12, wherein the control module: determines an input energy ratio among the phases of the electric motor based on the voltage commands and the measured currents; identifies the fault condition as a phase-to-phase short circuit fault condition when the input energy difference is greater than a first threshold value and the input energy ratio is greater than a second threshold value; and identifies the fault condition as an in-phase short circuit fault condition when the input energy difference is greater than the first threshold value and the input energy ratio is less than the second threshold value. ### Claim 16 (depends on 12) The vehicle of claim 12, wherein the control module determines the input energy difference by: determining an input energy value for each phase of the phases over an electrical period of the electric motor, resulting in a plurality of input energy values; identifying a maximum input energy value of the plurality of input energy values; identifying a minimum input energy value of the plurality of input energy values; and subtracting the minimum input energy value from the maximum input energy value to determine the input energy difference. ### Claim 17 (depends on 12) The vehicle of claim 12, further comprising an electronic control unit coupled to the control module to receive indication of the fault condition from the control module and initiate a remedial action in response the fault condition. ### Claim 18 A method for diagnosing stator windings in an electric motor, the method comprising: determining, for a first phase of stator windings of the electric motor, a first motor phase input energy metric for an electrical period of the electric motor by accumulating a first plurality of instantaneous input power values for the first phase during the electrical period; determining, for a second phase of stator windings of the electric motor, a second motor phase input energy metric for the electrical period of the electric motor by accumulating a second plurality of instantaneous input power values for the second phase during the electrical period, wherein each respective instantaneous input power value of the second plurality is concurrent to a respective instantaneous input power value of the first plurality; and identifying a short circuit fault condition when a difference between the first motor phase input energy metric and the second motor phase input energy metric is greater than a threshold value. ### Claim 19 (depends on 18) The method of claim 18, further comprising, in response to identifying the short circuit fault condition: determining a ratio of the first motor phase input energy metric to the second motor phase input energy metric; identifying a phase-to-phase short circuit fault condition when the ratio is greater than a second threshold value; and identifying an in-phase short circuit fault condition when the ratio is less than the second threshold value. ### Claim 20 (depends on 18) The method of claim 18, wherein: determining the first motor phase input energy metric further comprises: obtaining a first voltage command for the first phase at a first time during the electrical period; obtaining a first measured current through the first phase concurrently to obtaining the first voltage command; obtaining a second voltage command for the first phase at a second time during the electrical period; obtaining a second measured current through the first phase concurrently to obtaining the second voltage command; and determining the first motor phase input energy metric by adding a product of the first voltage command and the first measured current to a product of the second voltage command and the second measured current; and determining the second motor phase input energy metric further comprises: obtaining a third voltage command for the second phase concurrently to obtaining the first voltage command; obtaining a third measured current through the second phase concurrently to obtaining the third voltage command; obtaining a fourth voltage command for the second concurrently to obtaining the second voltage command; obtaining a fourth measured current through the second phase concurrently to obtaining the fourth voltage command; and determining the second motor phase input energy metric by adding a product of the third voltage command and the third measured current to a product of the fourth voltage command and the fourth measured current.