Method and apparatus for diagnosing a fault condition in an electric machine
First Claim
1. A fault diagnosis apparatus for diagnosing a fault condition in an electric machine, the electric machine comprising a rotor having an axis of rotation and comprising a plurality of permanent magnets, the fault diagnosis apparatus comprising:
- a magnetic flux density sensor which is configured such that rotation of the rotor causes each of the plurality of permanent magnets to pass the magnetic flux density sensor; and
a processor configured to;
measure values of magnetic flux density using the magnetic flux density sensor at a plurality of positions of the rotor;
analyse the measured values of magnetic flux density and compare a magnitude of a peak amplitude in a time or frequency domain with a reference value; and
,if the peak amplitude is below the reference value, determine that the electric machine has a fault condition,the processor being additionally configured to;
determine the difference between the magnitude of the peak amplitude and the reference value, wherein if the electric machine is determined to have a fault condition, the severity of the fault condition is determined based on the difference.
1 Assignment
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Accused Products
Abstract
A fault condition is diagnosed in an electric machine that includes a rotor and a plurality of permanent magnets. To do so, the rotor is rotated so that each of the plurality of permanent magnets passes a magnetic flux density sensor, and the values of magnetic flux density are measured using the magnetic flux density sensor at a plurality of positions of the rotor. The measured values of magnetic flux density are analyzed and a magnitude of a peak amplitude is compared in a time or frequency domain with a reference value. If the peak amplitude is below the reference value, the electric machine is determined to have a fault condition.
16 Citations
20 Claims
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1. A fault diagnosis apparatus for diagnosing a fault condition in an electric machine, the electric machine comprising a rotor having an axis of rotation and comprising a plurality of permanent magnets, the fault diagnosis apparatus comprising:
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a magnetic flux density sensor which is configured such that rotation of the rotor causes each of the plurality of permanent magnets to pass the magnetic flux density sensor; and a processor configured to; measure values of magnetic flux density using the magnetic flux density sensor at a plurality of positions of the rotor; analyse the measured values of magnetic flux density and compare a magnitude of a peak amplitude in a time or frequency domain with a reference value; and
,if the peak amplitude is below the reference value, determine that the electric machine has a fault condition, the processor being additionally configured to; determine the difference between the magnitude of the peak amplitude and the reference value, wherein if the electric machine is determined to have a fault condition, the severity of the fault condition is determined based on the difference. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A method for diagnosing a fault condition in an electric machine, the electric machine comprising a rotor having an axis of rotation and comprising a plurality of permanent magnets, the method comprising:
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rotating the rotor so that each of the plurality of permanent magnets passes a magnetic flux density sensor; measuring values of magnetic flux density using the magnetic flux density sensor at a plurality of positions of the rotor; analyzing the measured values of magnetic flux density and comparing a magnitude of a peak amplitude of magnetic flux density corresponding to each respective permanent magnet, the peak amplitude being in a time or frequency domain with a reference value of magnetic flux density; and if the peak amplitude is below the reference value, determining that the electric machine has a fault condition, the method further comprising; determining the difference between the magnitude of the peak amplitude and the reference value, wherein if the electric machine is determined to have a fault condition, the severity of the fault condition is determined based on the difference.
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20. A fault diagnosis apparatus for diagnosing a fault condition in an electric machine, the electric machine comprising a rotor having an axis of rotation and comprising a plurality of permanent magnets, the fault diagnosis apparatus comprising:
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a magnetic flux density sensor which is configured such that rotation of the rotor causes each of the plurality of permanent magnets to pass the magnetic flux density sensor; and a processor configured to; measure values of magnetic flux density using the magnetic flux density sensor at a plurality of positions of the rotor so that the magnetic flux density sensor is measuring magnetic flux based on different magnets in the rotor and on different rotational positions of the rotor; analyze the measured values of magnetic flux density and compare a magnitude of a peak amplitude in a time or frequency domain with a reference value; and if the peak amplitude is below the reference value, determine that the electric machine has a fault condition, the processor being additionally configured to; determine the difference between the magnitude of the peak amplitude and the reference value, wherein if the electric machine is determined to have a fault condition, the severity of the fault condition is determined based on the difference.
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Specification