Testing inverter driven electric motor shut-off path
First Claim
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1. A method of testing automotive vehicle electric traction motor shut-off paths, the method comprising the steps of:
- providing a three-phase electric motor having at least one shut-off path that is an electric traction motor of an automotive vehicle, a source of electric current, a current injection circuit connected to the source of electric current and to the three-phase electric motor, and current measurement circuitry and electrical communication with the three-phase electrical motor;
injecting current into the three-phase electric motor;
applying at least one of a short or an open to the three-phase electric motor for a predetermined length of time;
calculating a rate of decay of the current;
comparing the rate of decay wit predetermined decay criteria; and
determining that testing of the at least one shut-off path of the three-phase electric motor has passed if the rate of decay meets the predetermined decay criteria and that the at least one shut-off path has failed if the rate of decay does not meet the predetermined decay criteria.
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Abstract
A method for testing electric motor shut-off including injecting current into an electric motor, applying at least one of a short or an open to the electric motor for a predetermined length of time, calculating the rate of decay of the current and comparing rate of the decay with a predetermined decay criteria. In one implementation, a predefined sequence of opening and short circuiting the electric motor is used, and the shut-off path tests for the motor three phases can be verified with one test.
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Citations
20 Claims
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1. A method of testing automotive vehicle electric traction motor shut-off paths, the method comprising the steps of:
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providing a three-phase electric motor having at least one shut-off path that is an electric traction motor of an automotive vehicle, a source of electric current, a current injection circuit connected to the source of electric current and to the three-phase electric motor, and current measurement circuitry and electrical communication with the three-phase electrical motor; injecting current into the three-phase electric motor; applying at least one of a short or an open to the three-phase electric motor for a predetermined length of time; calculating a rate of decay of the current; comparing the rate of decay wit predetermined decay criteria; and determining that testing of the at least one shut-off path of the three-phase electric motor has passed if the rate of decay meets the predetermined decay criteria and that the at least one shut-off path has failed if the rate of decay does not meet the predetermined decay criteria. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of diagnosing faults in an automotive vehicle electric motor deactivation device, the method comprising the steps of:
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providing a three-phase electric motor having at least one shut-off path that comprises an electric traction motor of an automotive vehicle, a source of electric current, a three-phase inverter connected to the source of electric current and connected to three-phase electric motor, an electric motor position sensor, and a motor controller in electrical communication with the three-phase electric motor; injecting current into the three-phase electric motor using the three-phase inverter while the motor speed is substantially zero; disabling the inverter for a predetermined length of time; calculating a rate of current decay; and comparing the rate of current decay with predetermined decay criteria. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17)
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18. A method for checking an automotive vehicle electric motor deactivation device, comprising the steps of:
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providing a three-phase electric motor that is an electric traction motor of an automotive vehicle, a source of electric current, a current injection circuit connected to the source of electric current and connected to the three-phase electric motor that comprises a three-phase inverter and a motor controller in electrical communication with the three-phase electric motor, an electric motor rotor sensor, and a contactor between the source of electric current and the current injection circuit; checking whether the contactor is closed before current is injected; injecting current into the three-phase electric motor where the current is insufficient to cause motor rotation and includes a non-zero amp direct-axis current and a substantially zero amp quadrature axis current; measuring current in at least one phase of the three-phase motor; verifying that electric motor speed is substantially zero; applying a three-phase short to the three-phase electric motor for a predetermined length of time; calculating a first current decay as a result of the application of the three-phase short; comparing the first current decay with a current decay criteria; applying a three-phase open to the electric motor for another predetermined length of time; calculating a second current decay as a result of the application of the three-phase open; comparing the second current decay with another current decay criteria; and determining that the three-phase electric motor has passed if the first current decay meets the current decay criteria and the second current decay meets the another current decay criteria and has failed if either the first current decay does not meet the current decay criteria or the second current decay does not meet the another current decay criteria. - View Dependent Claims (19, 20)
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Specification