Demagnetization for a motor in an electric or partially electric motor vehicle
First Claim
1. A device for detecting faults due to permanent magnet degradation in a motor in a vehicle comprising:
- a permanent magnet induced voltage monitor that measures a detected permanent magnet induced voltage of the motor at a predetermined speed; and
a processor that;
compares the detected permanent magnet induced voltage with a reference voltage that reflects a permanent magnet induced voltage of the motor with a fully magnetized permanent magnet at the predetermined speed; and
analyzes the detected permanent magnet induced voltage with reference to the reference voltage to determine whether a characteristic of the detected permanent magnet induced voltage indicates a component of the motor is faulty.
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Accused Products
Abstract
In an electric or hybrid electric vehicle, a voltage monitor (102) is directly coupled to a traction motor (38) and/or generator motor (30) to detect a permanent magnet induced voltage within the motor at a predetermined speed and no load condition. A controller (100) compares the detected permanent magnet induced voltage with an expected reference voltage that represents an expected permanent magnet induced voltage at full magnetization and the predetermined speed. The comparison includes identifying points of synchronization and using those points to determine a difference in the detected permanent magnet induced voltage that is caused by a faulty component.
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Citations
20 Claims
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1. A device for detecting faults due to permanent magnet degradation in a motor in a vehicle comprising:
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a permanent magnet induced voltage monitor that measures a detected permanent magnet induced voltage of the motor at a predetermined speed; and
a processor that;
compares the detected permanent magnet induced voltage with a reference voltage that reflects a permanent magnet induced voltage of the motor with a fully magnetized permanent magnet at the predetermined speed; and
analyzes the detected permanent magnet induced voltage with reference to the reference voltage to determine whether a characteristic of the detected permanent magnet induced voltage indicates a component of the motor is faulty. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for identifying a component that is faulty and causing permanent magnet degradation in a motor of a vehicle, the method comprising the steps of:
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detecting a first signal that is a function of permanent magnetization of a plurality of permanent magnets in the motor;
comparing the first signal with a reference signal that represents a function of permanent magnetization of the plurality of magnets in the motor, wherein the reference signal reflects a level of magnetization that is expected where the plurality of permanent magnets in the motor are fully magnetized; and
analyzing a difference between the first signal and the reference signal to determine a faulty component that is likely causing the difference. - View Dependent Claims (8, 9, 10, 11, 12, 13)
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14. A device for identifying a component that is faulty and causing permanent magnet degradation in a motor of a vehicle, the device comprising:
a processor that;
receives a first signal that is a function of permanent magnetization of a plurality of permanent magnets in the motor;
compares the first signal with a reference signal that represents a function of permanent magnetization of the plurality of magnets in the motor, wherein the reference signal reflects a level of magnetization that is expected where the plurality of permanent magnets in the motor are fully magnetized;
analyzes a difference between the first signal and the reference signal to determine a faulty component that is likely causing the difference. - View Dependent Claims (15, 16, 17, 18, 19, 20)
Specification