# US 2017/0317615 A1 · Fault shutdown control of an electric machine in a vehicle or other dc-powered torque system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2017/0317615 A1 - Document ID: US20170317615A1 - Status: Published application - Kind: A1 - Application number: 15/142,416 - Filed: 2016-04-29 - Published: 2017-11-02 - Earliest claimed: 2016-04-29 - Assignees: GM Global Technology Operations LLC - Applicants: GM Global Technology Operations LLC - Inventors: Daniel J. Berry; Wei D. Wang; Bon Ho Bae; Brian A. Welchko; Wesley G. Zanardelli; Melissa R. McNeely - Web page: https://patentgrep.com/patent/US20170317615A1 ## CPC - H02P 3/12: by short-circuit or resistive braking - B60L 3/0061: {relating to electrical machines} - B60L 3/0069: {relating to the isolation, e.g. ground fault or leak current} - B60L 3/04: Cutting off the power supply under fault conditions (protective devices and circuit arrangements in general H01H; H02H) - H02H 3/023: {by short-circuiting} - H02H 7/0805: {for synchronous motors} - H02H 7/0838: {with H-bridge circuit} - H02P 29/024: Detecting a fault condition, e.g. short circuit, locked rotor, open circuit or loss of load - H02P 29/0241: {the fault being an overvoltage} - H02H 7/09: against over-voltage; against reduction of voltage; against phase interruption - Y02T 10/64: Electric machine technologies in electromobility - H02P: CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS - B60L: PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES (arrangements or mounting of electrical propulsion units or of plural diverse prime-movers for mutual or common propulsion in vehicles B60K1/00, B60K6/20; arrangements or mounting of electrical gearing in vehicles B60K17/12, B60K17/14; preventing wheel slip by reducing power in rail vehicles B61C15/08; dynamo-electric machines H02K; control or regulation of electric motors H02P); SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES (electric coupling devices combined with mechanical couplings of vehicles B60D1/64; electric heating for vehicles B60H1/00); ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL (control or regulation of electric motors H02P); MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES - H02H: EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS (indicating or signalling undesired working conditions G01R, e.g. G01R31/00, G08B; locating faults along lines G01R31/08; emergency protective devices H01H) - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract A torque system includes a DC power device, a polyphase electric machine, a contactor pair, a power inverter module (PIM), and a controller. The PIM connects to the power device via the contactor pair and directly connects to the electric machine. The controller executes a method to control a fault response under a fault condition resulting in opening of the contactor pair and a polyphase short condition. The controller calculates a back EMF of the electric machine and transmits switching control signals to semiconductor switches of the PIM to transition from the polyphase short condition to a polyphase open condition only when the calculated back EMF is less than a calibrated value and a voltage rise on a DC side of the PIM is less than a calibrated voltage rise. A vehicle includes the DC power device, road wheels, electric machine, PIM, and controller. ## Claims ### Claim 1 A direct current (DC)-powered torque system comprising: a DC power supply; a polyphase electric machine having an output shaft operable for transmitting an output torque; a DC voltage bus; an alternating current (AC) voltage bus; a contactor pair; a power inverter module (PIM) having a plurality of semiconductor switches, wherein the PIM is selectively connected to the DC power supply via the contactor pair and the DC voltage bus, and is directly connected to the electric machine via the AC voltage bus; and a controller programmed to execute a control action with respect to the torque system in response to a predetermined fault condition, wherein the predetermined fault condition results in an opening of the contactor pair and a polyphase short condition, the control action including: calculating a back electromotive force of the electric machine; and transmitting switching control signals to the semiconductor switches to transition from the polyphase short condition to a polyphase open condition only when the calculated back electromotive force is less than a calibrated value and a voltage rise on a DC side of the PIM is less than a calibrated voltage rise. ### Claim 2 (depends on 1) The DC-powered torque system of claim 1, wherein the polyphase electric machine is a permanent magnet-type synchronous electric machine. ### Claim 3 (depends on 1) The DC-powered torque system of claim 1, further comprising a driven member or load connected to the output shaft. ### Claim 4 (depends on 1) The DC-powered torque system of claim 1, wherein each semiconductor switch of the plurality of semiconductor switches is an IGBT. ### Claim 5 (depends on 1) The torque system of claim 1, wherein the plurality of semiconductor switches includes three or more semiconductor switching elements each having a pair of the semiconductor switches. ### Claim 6 (depends on 1) The torque system of claim 1, further comprising a DC link capacitor in electrical parallel with the plurality of semiconductor switches and a voltage sensor configured to measure a DC link voltage across the DC link capacitor, wherein the controller is operable for receiving the measured voltage and calculating the back EMF using the received DC link voltage. ### Claim 7 (depends on 6) The torque system of claim 6, wherein the controller includes a memory that is programmed with a set of calibrated values including an inductance of the electric machine and a DC link capacitance of the DC link capacitor, and wherein the controller is operable for calculating the back EMF using the set of calibrated values. ### Claim 8 A vehicle comprising: a direct current (DC) power supply; a set of road wheels; a three-phase electric machine having an output shaft operable for transmitting an output torque to the set of road wheels to thereby drive the road wheels and propel the vehicle; a contactor pair; a DC voltage bus; an alternating current (AC) voltage bus; a power inverter module (PIM) having a plurality of semiconductor switches, wherein the PIM is selectively connected to the DC power supply via the DC voltage bus and the contactor pair, and is directly connected to the electric machine via the AC voltage bus; and a controller programmed to execute a control action with respect to the torque system in response to a predetermined fault condition, wherein the predetermined fault condition results in an opening of the contactor pair and a three-phase short condition, the control action including: calculating a back electromotive force of the electric machine; and transmitting switching control signals to the semiconductor switches to transition from the three-phase short condition to a three-phase open condition only when the calculated back electromotive force is less than a calibrated value and a voltage rise on a DC side of the PIM is less than a calibrated voltage rise. ### Claim 9 (depends on 8) The vehicle of claim 8, wherein the three-phase electric machine is a permanent magnet-type synchronous electric machine. ### Claim 10 (depends on 8) The vehicle of claim 8, wherein each semiconductor switch of the plurality of semiconductor switches is an IGBT. ### Claim 11 (depends on 8) The vehicle of claim 8, wherein the plurality of semiconductor switches includes three or more semiconductor switching elements each having a pair of the semiconductor switches. ### Claim 12 (depends on 8) The vehicle of claim 8, further comprising a DC link capacitor in electrical parallel with the plurality of semiconductor switches and a voltage sensor configured to measure a DC link voltage across the DC link capacitor, wherein the controller is operable for receiving the measured voltage and calculating the back EMF using the received DC link voltage. ### Claim 13 (depends on 8) The vehicle of claim 8, wherein the controller includes a memory that is programmed with a set of calibrated values including an inductance of the electric machine and a DC link capacitance of the DC link capacitor, and wherein the controller is operable for calculating the back EMF using the set of calibrated values. ### Claim 14 A method of controlling a direct current (DC)-powered torque system in response to a predetermined fault condition, wherein the torque system includes a DC power supply, a power inverter module (PIM) connected to the DC power supply via a contactor pair and a DC bus, and an electric machine connected to the PIM via an AC bus, and wherein the predetermined fault condition is a fault resulting in an opening of the contactor pair and a three-phase short condition, the method comprising: detecting the predetermined fault condition via a controller; calculating a back electromotive force of the electric machine; and transmitting switching control signals from the controller to a plurality of semiconductor switches of the PIM to thereby transition from the three-phase short condition to a three-phase open condition only when the calculated back electromotive force is less than a calibrated value and a voltage rise on a DC side of the PIM is less than a calibrated voltage rise. ### Claim 15 (depends on 14) The method of claim 14, wherein the system includes a DC link capacitor in electrical parallel with the plurality of semiconductor switches and a voltage sensor configured to measure a DC link voltage across the DC link capacitor, wherein calculating a back electromotive force of the electric machine includes calculating the back EMF using the measured DC link voltage. ### Claim 16 (depends on 15) The method of claim 15, wherein the controller includes a memory that is programmed with a set of calibrated values including an inductance of the electric machine and a DC link capacitance of the DC link capacitor, and wherein calculating the back EMF includes solving a function that includes the set of calibrated values. ### Claim 17 (depends on 16) The method of claim 16, wherein the function is: V CF = 3 2  L d  I d 2 C L ++  V CI 2 where VCF is the back EMF, Ld is a d-axis-based inductance of the electric machine, Id is a d-axis-based current of the electric machine, CL is the DC link capacitance, and VCI is the DC link voltage at an onset of the transition.