Method and apparatus for determining faults in an electric assist steering system
First Claim
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1. A method for determining a fault in a system including an electric motor, said method comprising the steps of:
- determining a calculated star voltage of the electric motor comprising the steps of;
determining phase voltages to apply to the phases of the electric motor; and
determining the sum of said phase voltages, said calculated star voltage being equal to one-third of said sum of said phase voltages;
determining a measured star voltage of the electric motor;
comparing said calculated star voltage to said measured star voltage of the electric motor to determine a star voltage error; and
determining the fault in the system when said star voltage error exceeds a predetermined maximum star voltage error.
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Abstract
A method and apparatus for determining a fault in an electric motor (50) determines a calculated star voltage (Vstar
24 Citations
6 Claims
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1. A method for determining a fault in a system including an electric motor, said method comprising the steps of:
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determining a calculated star voltage of the electric motor comprising the steps of; determining phase voltages to apply to the phases of the electric motor; and determining the sum of said phase voltages, said calculated star voltage being equal to one-third of said sum of said phase voltages; determining a measured star voltage of the electric motor; comparing said calculated star voltage to said measured star voltage of the electric motor to determine a star voltage error; and determining the fault in the system when said star voltage error exceeds a predetermined maximum star voltage error. - View Dependent Claims (2)
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3. A method for determining a fault in a system including an electric motor, said method comprising the steps of:
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determining a calculated star voltage of the electric motor; determining a measured star voltage of the electric motor; comparing said calculated star voltage to said measured star voltage of the electric motor to determine a star voltage error by determining an absolute difference between said calculated star voltage and said measured star voltage; and determining the fault in the system when said star voltage error exceeds a predetermined maximum star voltage error.
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4. Apparatus for determining a fault in a system including an electric motor, said apparatus comprising:
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means for determining a calculated star voltage of the electric motor comprising; means for determining phase voltages to apply to the phases of the electric motor; and means for determining the sum of said phase voltages, said calculated star voltage being equal to one-third of said sum of said phase voltages; means for determining a measured star voltage of the electric motor; means for comparing said calculated star voltage to said measured star voltage of the electric motor to determine a star voltage error; and means for determining the fault in the system when said star voltage error exceeds a predetermined maximum star voltage error. - View Dependent Claims (5)
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6. Apparatus for determining a fault in a system including an electric motor, said apparatus comprising:
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means for determining a calculated star voltage of the electric motor comprising means for determining an absolute difference between said calculated star voltage and said measured star voltage; means for determining a measured star voltage of the electric motor; means for comparing said calculated star voltage to said measured star voltage of the electric motor to determine a star voltage error; and means for determining the fault in the system when said star voltage error exceeds a predetermined maximum star voltage error.
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Specification