Method and apparatus for alternator stator turn-to-turn short detection
First Claim
1. A method for determining whether a turn-to-turn short circuit is occurring in a stator winding of an alternator, said method comprising:
- determining an output voltage or current of the alternator, where the output voltage or current includes an alternator ripple current frequency as a result of an AC-to-DC conversion of the output of the alternator;
determining a speed of the alternator;
determining the alternator ripple current frequency of the alternator from the speed of the alternator;
determining a winding ripple current frequency from the alternator ripple current frequency;
determining an amplitude of the winding ripple current frequency;
comparing the amplitude of the winding ripple current frequency to a predetermined amplitude; and
determining that a turn-to-turn short circuit is occurring if the difference between the amplitude of the winding ripple current frequency and the predetermined amplitude is greater than a predetermined threshold.
3 Assignments
0 Petitions
Accused Products
Abstract
A method for detecting whether the stator in a vehicle alternator has a turn-to-turn short circuit. The method includes determining an output current or voltage signal of the alternator, where the output current or voltage signal includes a ripple current frequency as a result of an AC-to-DC conversion. The method determines the speed of the alternator and a current output of the alternator. The method then determines the ripple current frequency of the alternator from the alternator speed, and determines a winding frequency from the ripple current frequency. The method performs an FFT analysis on the voltage and current signal, determines an amplitude of the winding frequency and compares the amplitude of the winding frequency to a predetermined amplitude, where if the difference exceeds a predetermined threshold, a turn-to-turn short circuit is likely occurring.
15 Citations
20 Claims
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1. A method for determining whether a turn-to-turn short circuit is occurring in a stator winding of an alternator, said method comprising:
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determining an output voltage or current of the alternator, where the output voltage or current includes an alternator ripple current frequency as a result of an AC-to-DC conversion of the output of the alternator; determining a speed of the alternator; determining the alternator ripple current frequency of the alternator from the speed of the alternator; determining a winding ripple current frequency from the alternator ripple current frequency; determining an amplitude of the winding ripple current frequency; comparing the amplitude of the winding ripple current frequency to a predetermined amplitude; and determining that a turn-to-turn short circuit is occurring if the difference between the amplitude of the winding ripple current frequency and the predetermined amplitude is greater than a predetermined threshold. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for determining whether a turn-to-turn short circuit is occurring in a stator winding of an alternator, said method comprising:
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measuring a battery current or voltage of a vehicle that is being charged by the alternator, where the battery current or voltage measurement includes an alternator ripple current frequency as a result of an AC-to-DC conversion of the output voltage or current; determining a speed of the alternator; estimating an output current of the alternator based on the speed of the alternator and a field duty cycle of the alternator; determining the alternator ripple current frequency of the alternator from the speed of the alternator; determining a winding ripple current frequency from the alternator ripple current frequency; performing a single-frequency fast Fourier transform (FFT) analysis of the output voltage or current of the alternator to generate a frequency spectrum; determining an amplitude of the winding ripple current frequency from the frequency spectrum; comparing the amplitude of the winding ripple current frequency to a predetermined amplitude; and determining that a turn-to-turn short circuit is occurring if the difference between the amplitude of the winding ripple current frequency and the predetermined amplitude is greater than a predetermined threshold over the speed and current of the alternator. - View Dependent Claims (12, 13, 14, 15)
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16. A system for determining whether a turn-to-turn short circuit is occurring in a stator winding of an alternator, said system comprising:
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means for determining an output voltage or current of the alternator, where the output voltage or current includes an alternator ripple current frequency as a result of an AC-to-DC conversion of the output of the alternator; means for determining a speed of the alternator; means for determining the alternator ripple current frequency of the alternator from the speed of the alternator; means for determining a winding ripple current frequency from the alternator ripple current frequency; means for determining an amplitude of the winding ripple current frequency; means for comparing the amplitude of the winding ripple current frequency to a predetermined amplitude; and means for determining that a turn-to-turn short circuit is occurring if the difference between the amplitude of the winding ripple current frequency and the predetermined amplitude is greater than a predetermined threshold. - View Dependent Claims (17, 18, 19, 20)
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Specification