Method, system, and computer-readable medium for sensorless measurement of induction machine rotor bar pass frequency
First Claim
Patent Images
1. A method comprising:
- (a) sampling a current waveform of an induction machine to obtain sampled points;
(b) characterizing the sampled current over a selected first time window to obtain characterized points;
(c) subtracting the characterized points from respective sampled points to obtain a residual signal comprising residual points;
(d) obtaining a frequency spectrum representative of the residual signal over a selected second time window; and
(e) identifying a rotor bar pass frequency from the frequency spectrum.
1 Assignment
0 Petitions
Accused Products
Abstract
A method comprises: sampling a current waveform of an induction machine to obtain sampled points; characterizing the sampled current over a selected first time window to obtain characterized points; subtracting the characterized points from respective sampled points to obtain a residual signal comprising residual points; obtaining a frequency spectrum representative of the residual signal over a selected second time window; and identifying a rotor bar pass frequency from the frequency spectrum. The method is typically carried out by a system comprising a computer, a computer-readable medium, or combinations thereof.
13 Citations
52 Claims
-
1. A method comprising:
-
(a) sampling a current waveform of an induction machine to obtain sampled points;
(b) characterizing the sampled current over a selected first time window to obtain characterized points;
(c) subtracting the characterized points from respective sampled points to obtain a residual signal comprising residual points;
(d) obtaining a frequency spectrum representative of the residual signal over a selected second time window; and
(e) identifying a rotor bar pass frequency from the frequency spectrum. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
-
-
16. A method for sensorless measurement of induction machine (22) speed, the method comprising:
-
(a) sampling a current waveform of the induction machine at a sampling frequency higher than a fundamental frequency of the induction machine to obtain sampled points;
(b) characterizing the sampled current over a selected first time window comprising a multiple of a fundamental period of the induction machine to obtain characterized points;
(c) subtracting the characterized points from respective sampled points to obtain a residual signal comprising residual points;
(d) obtaining a frequency spectrum representative of the residual signal over a selected second time window, wherein a beginning of the second time window is defined by a selected point;
(e) multiplying an approximate speed by the number of rotor bars of the machine to obtain an approximate bar pass frequency;
(f) obtaining at least one significant side band of the approximate bar pass frequency; and
(g) obtaining a rotor bar pass frequency from the at least one significant side band. (h) obtaining an induction machine speed from the rotor bar pass frequency. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
-
-
27. A system comprising a computer configured for:
-
(a) sampling a current waveform of an induction machine to obtain sampled points;
(b) characterizing the sampled current over a selected first time window to obtain characterized points;
(c) subtracting the characterized points from respective sampled points to obtain a residual signal comprising residual points;
(d) obtaining a frequency spectrum representative of the residual signal over a selected second time window; and
(e) identifying a rotor bar pass frequency from the frequency spectrum. - View Dependent Claims (28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39)
-
-
40. A computer-readable medium storing computer instructions for instructing a computer, the computer instructions comprising:
-
(a) sampling a current waveform of an induction machine to obtain sampled points;
(b) characterizing the sampled current over a selected first time window to obtain characterized points;
(c) subtracting the characterized points from respective sampled points to obtain a residual signal comprising residual points;
(d) obtaining a frequency spectrum representative of the residual signal over a selected second time window; and
(e) identifying a rotor bar pass frequency from the frequency spectrum. - View Dependent Claims (41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52)
-
Specification