LINEAR HALL-BASED ECCENTRICITY DIAGNOSIS METHOD AND DETECTION SYSTEM FOR PERMANENT MAGNET MOTOR

Abstract

A linear Hall-based eccentricity diagnosis method and detection system for a permanent magnet motor. First, three linear Hall elements are mounted in stator slots at the same space interval, respectively; second, analog signals output by the three-phase linear Hall are converted into digital signals by means of a digital signal processor, and the digital signals are converted into a quadrature signal by means of linear combination; then, a negative sequence signal and a sideband signal are extracted from the quadrature signal by means of a complex factor filter; then the amplitude of the negative sequence signal and the amplitude of the sideband signal are extracted by means of synchronous reference frame phase-locked loops as a static eccentricity indicator and a dynamic eccentricity indicator; finally, percentages representing the degrees of eccentricity are calculated from the static eccentricity indicator and the dynamic eccentricity indicator in the digital signal processor.

Claims

1. A linear Hall-based eccentricity diagnosis method for a permanent magnet motor, a first linear Hall element, a second linear Hall element and a third linear Hall element are mounted in the stator slots at the same space interval in a circumferential direction, magnetically sensitive surfaces of the first to third linear Hall elements are all opposite surfaces of a rotor with permanent magnets, output voltages of the first to third linear Hall elements are linearly combined to obtain a quadrature signal containing a pair of quadrature components and a DC component, positive sequence signals, negative sequence signals and sideband signals are extracted from the quadrature signal, the amplitude of the negative sequence signals extracted thereby is taken as a static eccentricity indicator, the amplitude of the sideband signals extracted thereby is taken as a dynamic eccentricity indicator, a static eccentricity percentage is obtained by the ratio of the static eccentricity indicator to the amplitude of the positive sequence signals, and a dynamic eccentricity percentage is obtained by the ratio of the dynamic eccentricity indicator to the amplitude of the positive sequence signals.

2. The linear Hall-based eccentricity diagnosis method for the permanent magnet motor according to claim 1, wherein the quadrature signal containing a pair of quadrature components and a DC component obtained by a linear combination of the output voltages of the first to third linear Hall elements is expressed as: H.sub.??0=T.sub.APSH.sub.??0, in which H.sub.abc is a vector composed of the output voltages of the first to third linear Hall elements; H.sub.abc=[H.sub.a, H.sub.b, H.sub.c].sup.T, in which H.sub.a is the output voltage of the second linear Hall element, H.sub.b is the output voltage of the first linear Hall element, H.sub.c is the output voltage of the third linear Hall element, and H.sub.??0 is the quadrature signal; H.sub.??0=[H.sub.?, H.sub.?, H.sub.0].sup.T, in which H.sub.? and H.sub.? are the quadrature components, H.sub.0 is the DC component, and T.sub.APS is a linear combination coefficient matrix; $T_{\mathrm{APS}}=K\left[\begin{array}{ccc}1& \cos {?}_s& \cos {?}_s\\ 0& \sin {?}_s& -\sin {?}_s\\ -\cos {?}_s& 1/2& 1/2\end{array}\right],$ $K=\left[\begin{array}{ccc}\frac{1}{1+2{\cos }^2{?}_s}& 0& -\frac{1+2\cos {?}_s}{\left(1-\cos {?}_s\right)\left(1+2{\cos }^2{?}_s\right)}\\ 0& \frac{1}{2{\sin }^2{?}_s}& 0\\ 0& 0& \frac{1}{1-\cos {?}_s}\end{array}\right],$ in which ?.sub.s is an electrical angle between two adjacent linear Hall elements.

3. The linear Hall-based eccentricity diagnosis method for the permanent magnet motor according to claim 1, wherein the positive sequence signal extracted thereby is expressed as: $F_1\left(s\right)=\frac{{?}_c}{s-j{?}_0+{?}_c},$ in which F.sub.1(s) is an expression of the positive sequence signal in the s domain, ?.sub.0 is the frequency of the positive sequence signal, w is a cut-off frequency, ?.sub.c=k.sub.c*?.sub.0, k.sub.c is a positive number.

4. The linear Hall-based eccentricity diagnosis method for the permanent magnet motor according to claim 1, wherein the negative sequence signal extracted thereby is expressed as: $F_2\left(s\right)=\frac{{?}_c}{s+j{?}_0+{?}_c},$ in which F.sub.2(s) is an expression of the negative sequence signal in the s domain, ?.sub.0 is the frequency of the positive sequence signal, ?.sub.c is a cut-off frequency, ?.sub.c=k.sub.c*?.sub.0, k.sub.c is a positive number.

5. The linear Hall-based eccentricity diagnosis method for the permanent magnet motor according to claim 1, wherein the sideband signal extracted thereby is expressed as: $F_3\left(s\right)=\frac{{?}_c}{s-j\left(1-1/p\right){?}_0+{?}_c},$ in which F.sub.3(s) is an expression of the sideband signal in the s domain, ?.sub.0 is the frequency of the positive sequence signal, w is a cut-off frequency, ?.sub.c=k.sub.c*?.sub.0, k.sub.c is a positive number, and p is the number of pole pairs of the permanent magnet motor.

6. The linear Hall-based eccentricity diagnosis method for the permanent magnet motor according to claim 1, wherein the static eccentricity percentage is twice the ratio of the static eccentricity indicator to the amplitude of the positive sequence signal.

7. The linear Hall-based eccentricity diagnosis method for the permanent magnet motor according to claim 1, wherein the method is used to detect a stator permanent magnet motor or a rotor permanent magnet motor.

8. A linear Hall-based eccentricity detection system for a permanent magnet motor, comprising: a first linear Hall element mounted in stator slots, and magnetically sensitive surfaces of the first linear Hall element are opposite surfaces of a rotor with permanent magnets; a second linear Hall element mounted in the stator slots and spaced apart from the first linear Hall element in a circumferential direction by an electrical angle phase difference of cos, and magnetically sensitive surfaces of the second linear Hall element are opposite surfaces of a rotor with permanent magnets; a third linear Hall element mounted in the stator slots and spaced apart from the first linear Hall element in a circumferential direction by an electrical angle phase difference of cos, and magnetically sensitive surfaces of the third linear Hall element are opposite surfaces of a rotor with permanent magnets; and a digital signal processor, wherein output voltages of the first to third linear Hall elements are linearly combined to obtain a quadrature signal containing a pair of quadrature components and a DC component, positive sequence signals, negative sequence signals and sideband signals are extracted from the quadrature signal, the amplitude of the negative sequence signals extracted thereby is taken as a static eccentricity indicator, the amplitude of the sideband signals extracted thereby is taken as a dynamic eccentricity indicator, a static eccentricity percentage is obtained by the ratio of the static eccentricity indicator to the amplitude of the positive sequence signals, and a dynamic eccentricity percentage is obtained by the ratio of the dynamic eccentricity indicator to the amplitude of the positive sequence signals.

9. The linear Hall-based eccentricity detection system for the permanent magnet motor according to claim 8, wherein the digital signal processor comprises: a linear combination unit, which receives the output voltages of the first to third linear Hall elements, and outputs a quadrature signal containing a pair of quadrature components and a DC component; a complex factor filter, an input end of the complex factor filter is connected to an output end of the linear combination unit, positive sequence signals, negative sequence signals and sideband signals are extracted from the quadrature signal and then output; phase-locked loops of a first synchronous reference system, which receives the negative sequence signal output by the complex factor filter, and extracts the amplitude of the negative sequence signal and then outputs; phase-locked loops of a second synchronous reference system, which receives the sideband signal output by the complex factor filter, and extracts the amplitude of the sideband signal and then outputs; and a calculation unit, which receives the amplitude of the negative sequence signal and the amplitude of the sideband signal output by the complex factor filter, receives the positive sequence signal output by the complex factor filter, calculates the ratio of the amplitude of the negative sequence signal to the amplitude of the positive sequence signal and then outputs a static eccentricity percentage, calculates the ratio of the amplitude of the sideband signal to the amplitude of the positive sequence signal and then outputs a dynamic eccentricity percentage.

10. The linear Hall-based eccentricity detection system for the permanent magnet motor according to claim 9, wherein the complex factor filter comprises: a first addition and subtraction combination module, a first input end of the first addition and subtraction combination module is connected to the quadrature signal, and a second input of the first addition and subtraction combination module is connected to an output end of a fifth addition and subtraction combination module, and outputs an intermediate signal after eliminating the positive sequence signal, negative sequence signal, and sideband signal from the quadrature signal; a second addition and subtraction combination module, a first input end of the second addition and subtraction combination module is connected to an output end of the first addition and subtraction combination module, and a second output end of the second addition and subtraction combination module is connected to an output end of a first detection filter, and outputs an accumulation result of the intermediate signal and the positive sequence signal; a third addition and subtraction combination module, a first input end of the third addition and subtraction combination module is connected to an output end of the first addition and subtraction combination module, and a second output end of the third addition and subtraction combination module is connected to an output end of a second detection filter, and outputs an accumulation result of the intermediate signal and the negative sequence signal; a fourth addition and subtraction combination module, a first input end of the fourth addition and subtraction combination module is connected to an output end of the first addition and subtraction combination module, and a second output end of the fourth addition and subtraction combination module is connected to an output end of a third detection filter, and outputs an accumulation result of the intermediate signal and the sideband signal; the first detection filter, wherein an input end of the first detection filter is connected to an output end of the second addition and subtraction combination module and outputs the positive sequence signal; the second detection filter, wherein an input end of the second detection filter is connected to an output end of the third addition and subtraction combination module and outputs the negative sequence signal; and the third detection filter, wherein an input end of the third detection filter is connected to an output end of the fourth addition and subtraction combination module and outputs the sideband signal.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0025] FIG. 1 is a block diagram of a linear hall-based eccentricity detection system for permanent magnet motor provided in the present invention.

[0026] FIG. 2 is a rotor permanent magnet motor in Embodiment 1.

[0027] FIG. 3 is a stator permanent magnet motor in Embodiment 2.

[0028] FIG. 4 is a block diagram of a complex factor filter in a linear Hall-based eccentricity diagnosis method and a detection system for a permanent magnet motor provided in the present invention.

[0029] FIG. 5 is a waveform diagram of three-phase signals output by three linear Hall elements and their corresponding quadrature signal, negative sequence signal, and sideband signal in Embodiment 1.

[0030] Description of reference numerals in the drawings:

[0031] 1. first linear Hall element;

[0032] 2. second linear Hall element;

[0033] 3. third linear Hall element;

[0034] 4. motor under detection;

[0035] 6. linear combination unit;

[0036] 8. complex factor filter;

[0037] 13. digital signal processor;

[0038] 14. first addition and subtraction combination module;

[0039] 15. second addition and subtraction combination module;

[0040] 16. third addition and subtraction combination module;

[0041] 17. fourth addition and subtraction combination module; and

[0042] 18. fifth addition and subtraction combination module.

DESCRIPTION OF EMBODIMENTS

[0043] The technical solution of the present invention will be further described below in conjunction with the accompanying drawings.

Embodiment 1: Diagnosing an Eccentricity of a Rotor Permanent Magnet Motor on the Basis of Linear Hall Elements

[0044] With reference to FIG. 1, the present invention provides a linear Hall-based eccentricity diagnosis method and a detection system for a permanent magnet motor, the detection system includes: a first linear Hall element 1, a second linear Hall element 2 and a third linear Hall element 3 mounted in a stator slot of a motor under detection 4, and a digital signal processor 13 for processing the output voltage of the Hall elements. As shown in FIG. 2, the motor under detection 4 is a three-phase 18-slot and 20-pole rotor permanent magnet motor. Three linear Hall elements are mounted in the stator slots at intervals of 2 stator slot pitches, and magnetically sensitive surfaces of the Hall elements are all opposite surfaces of a rotor with permanent magnets; among the three linear Hall elements, the first linear Hall element 1 is mounted in any slot of the stator, the second linear Hall element 2 is spaced apart from the first linear Hall element 1 in a circumferential direction by an electrical angle phase difference of ?.sub.s=2 ?/9, and the third linear Hall element 3 is spaced apart from the second linear Hall element 2 in a circumferential direction by an electrical angle phase difference of ?.sub.s=2 ?/9.

[0045] Taking the counterclockwise direction as a forward direction, when the rotor rotates in the forward direction at a constant speed, an electrical angle phase difference of output voltage signals between the first linear Hall element 1 and the second linear Hall element 2 is ?.sub.s=2 ?/9, and an electrical angle phase difference of output voltage signals between the second linear Hall element 2 and the third linear Hall element 3 is ?.sub.s=2 ?/9.

[0046] The three linear Hall elements are connected to the digital signal processor 13. The power supply voltage of the digital signal processor 13 is 3.3 V. H a signal comes from the second linear Hall element 2, H.sub.b signal comes from the second linear Hall element 1, H.sub.c signal comes from the second linear Hall element 3, and the three linear Hall elements output analog voltages ranging from 0 V to 3.3 V. In the digital signal processor 13, the output voltage signals of the three linear Hall elements are converted into three-phase original digital signals, expressed as H.sub.abc=[H.sub.a, H.sub.b, H.sub.c].sup.T.

[0047] The three-phase signals are made as a linear combination, shown in the following formula:

[00005]$H_{\mathrm{??}0}=T_{\mathrm{APS}}{H}_{\mathrm{abc}}$$\mathrm{wherein}:T_{\mathrm{APS}}=\mathrm{KT}=K\left[\begin{array}{ccc}1& \cos \frac{2?}{9}& \cos \frac{2?}{9}\\ 0& \sin \frac{2?}{9}& -\sin \frac{2?}{9}\\ -\cos \frac{2?}{9}& 1/2& 1/2\end{array}\right]$$K=\left[\begin{array}{ccc}\frac{1}{1+2{\cos }^2\frac{2?}{9}}& 0& -\frac{1+2\cos \frac{2?}{9}}{\left(1-\cos \frac{2?}{9}\right)\left(1+2{\cos }^2\frac{2?}{9}\right)}\\ 0& \frac{1}{2{\sin }^2\frac{2?}{9}}& 0\\ 0& 0& \frac{1}{1-\cos \frac{2?}{9}}\end{array}\right]$

[0048] The quadrature signal obtained upon the linear combination processing is H.sub.??0=[H.sub.?, H.sub.?, H.sub.0].sup.T.

[0049] A complex factor filter with harmonic selection capability is configured to extract negative sequence signals and sideband signals from the quadrature signal.

[0050] As shown in FIG. 4, the complex factor filter is composed of a first detection filter, a second detection filter and a third detection filter that are interconnected to one another. The quadrature signal minus the output of the three detection filters is taken as an intermediate signal, which is completed by a first addition and subtraction combination module 14, and the output of the three detection filters is summed by a fifth addition and subtraction combination module 18 and then transmitted to the first addition and subtraction combination module 14. The intermediate signal is added to the output signal of the first detection filter as the input signal of the first detection filter, which is completed by a second addition and subtraction combination module 15; the intermediate signal is added to the output signal of the second detection filter as the input signal of the second detection filter, which is completed by a third addition and subtraction combination module 16; and the intermediate signal is added to the output signal of the third detection filter as the input signal of the third detection filter, which is completed by a fourth addition and subtraction combination module 17.

[0051] The first detection filter extracts positive sequence signal having the same frequency as the rotating electrical frequency of the motor rotor from the quadrature signal, and the first detection filter can be expressed as:

[00006]$F_1\left(s\right)=\frac{{?}_c}{s-j{?}_0+{?}_c}$

[0052] wherein, ?.sub.0 is the frequency of the positive sequence signal, ?.sub.0=k.sub.c*?.sub.0, k.sub.c=0.707.

[0053] The second detection filter extracts negative sequence signal having the same frequency as the rotating electrical frequency of the motor rotor from the quadrature signal, and the second detection filter can be expressed as:

[00007]$F_2\left(s\right)=\frac{{?}_c}{s+j{?}_0+{?}_c}$

[0054] The third detection filter extracts sideband signals near the positive sequence signal from the quadrature signal, and the third detection filter can be expressed as:

[00008]$F_3\left(s\right)=\frac{{?}_c}{s-j\left(1-1/p\right){?}_0+{?}_c}$

[0055] wherein, p is the number of pole pairs of the permanent magnet motor, and p=10.

[0056] The amplitude of the negative sequence signals is extracted by means of phase-locked loops of a first synchronous reference system as a static eccentricity indicator, and the amplitude of the negative sequence signals is extracted by means of phase-locked loops of a second synchronous reference system as a dynamic eccentricity indicator.

[0057] Finally, twice the ratio of the static eccentricity indicator to the amplitude of the positive sequence component is taken as a static eccentricity percentage; the ratio of the dynamic eccentricity indicator to the amplitude of the positive sequence component is taken as a dynamic eccentricity percentage, and the percentage value is taken as an eccentricity diagnosis quantity.

[0058] The following simulation is performed in combination with specific eccentricity conditions, and the results are illustrated in FIG. 5, which shows the three-phase signal, quadrature signal, negative sequence signal and sideband signal, respectively. The amplitude of the negative sequence signals extracted by means of the phase-locked loops of a first synchronous reference system is shown by a dotted line, and the amplitude of the negative sequence signals is extracted by means of the phase-locked loops of a second synchronous reference system is shown by a dotted line.

[0059] (1) Before 0.3 s, the motor under detection 4 is in a non-eccentric state, and the signal frequency is 600 Hz. The negative sequence component output by the complex factor filter is 0; and the sideband component is 0.

[0060] (2) Between 0.3 s and 0.7 s, the signal frequency is 600 Hz, the motor under detection 4 is in a static eccentric state, and the static eccentric distance is 0.3 times the air gap length. The amplitude of the negative sequence signals output by the complex factor filter rises and stabilizes to be a constant value; the amplitude of the sideband signals first rises and then converges to 0. Since the dynamic eccentricity is a time-varying static eccentricity, there will be malfunctions when the static eccentricity first appears, but a predicted value of the dynamic eccentricity will converge to the actual value in a short time.

[0061] (3) Between 0.7 s and 1.1 s, the signal frequency is 600 Hz, the motor under detection 4 is in a mixed eccentric state, the static eccentric distance is 0.3 times the air gap length, and the dynamic eccentric distance is 0.2 times the air gap length. The amplitude of the negative sequence signals output by the complex factor filter remains basically unchanged; the amplitude of the sideband signals rises and remains basically unchanged.

[0062] (4) Between 1.1 s and 1.5 s, the signal frequency is 600 Hz, the motor under detection 4 is in a mixed eccentric state, the static eccentric distance is 0.3 times the air gap length, and the speed changes from 600 Hz to 200 Hz. The results of eccentricity detection remain basically unchanged, and the system is suitable for different speeds.

[0063] Finally, twice the ratio of the static eccentricity indicator to the amplitude of the positive sequence component is taken as a static eccentricity percentage 30%; and the ratio of the dynamic eccentricity indicator to the amplitude of the positive sequence component is taken as a dynamic eccentricity percentage 20%.

Embodiment 2: Diagnosing an Eccentricity of a Stator Permanent Magnet Motor on the Basis of Linear Hall Elements

[0064] With reference to FIG. 1, the present invention provides a linear Hall-based eccentricity diagnosis method and detection system for permanent magnet motor, and as shown in FIG. 4, the motor under detection is a three-phase 12-slot and 10-pole stator permanent magnet motor. Three linear Hall elements are mounted in the stator slots at intervals of 1 stator slot pitch. Magnetically sensitive surfaces of the Hall elements are all opposite salient-pole surfaces of a rotor with permanent magnets; among the three linear Hall elements, the first linear Hall element 1 is mounted in any slot of the stator, the second linear Hall element 2 is spaced apart from the first linear Hall element 1 in the same direction by an electrical angle phase difference of ?.sub.s=2 ?/3, and the third linear Hall element 3 is spaced apart from the second linear Hall element 2 in the same direction by an electrical angle phase difference of ?.sub.s=2 ?/3.

[0065] Taking the counterclockwise direction as a forward direction, when the rotor rotates in the forward direction at a constant speed, an electrical angle phase difference of output voltage signal between the first linear Hall element 1 and the second linear Hall element 2 is ?.sub.s=2 ?/3, and an electrical angle phase difference of output voltage signal between the second linear Hall element 2 and the third linear Hall element 3 is ?.sub.s=2 ?/3.

[0066] The three linear Hall elements are connected to the digital signal processor 13. The power supply voltage of the digital signal processor 13 is 3.3 V. H.sub.a signal comes from the second linear Hall element 2, H.sub.b signal comes from the second linear Hall element 1, H.sub.c signal comes from the second linear Hall element 3, and the three linear Hall elements output analog voltages ranging from 0 V to 3.3 V. In the digital signal processor, the output voltage signals of the three linear Hall elements are converted into three-phase original digital signal, expressed as H.sub.abc=[H.sub.a, H.sub.b, H.sub.c].sup.T.

[0067] A progressive linear combination of the three-phase signals is as follows:

[00009]$H_{\mathrm{??}0}=T_{\mathrm{APS}}{H}_{\mathrm{abc}}$$\mathrm{wherein}:T_{\mathrm{APS}}=\mathrm{KT}=K\left[\begin{array}{ccc}1& \cos \frac{2?}{9}& \cos \frac{2?}{9}\\ 0& \sin \frac{2?}{9}& -\sin \frac{2?}{9}\\ -\cos \frac{2?}{9}& 1/2& 1/2\end{array}\right]$$K=\left[\begin{array}{ccc}\frac{1}{1+2{\cos }^2\frac{2?}{9}}& 0& -\frac{1+2\cos \frac{2?}{9}}{\left(1-\cos \frac{2?}{9}\right)\left(1+2{\cos }^2\frac{2?}{9}\right)}\\ 0& \frac{1}{2{\sin }^2\frac{2?}{9}}& 0\\ 0& 0& \frac{1}{1-\cos \frac{2?}{9}}\end{array}\right]$

[0068] The processed quadrature signal is H.sub.??0=[H.sub.?, H.sub.?, H.sub.0].sup.T.

[0069] A complex factor filter with harmonic selection capability is configured to extract negative sequence signals and sideband signals from the quadrature signal.

[0070] The complex factor filter is composed of a first detection filter, a second detection filter and a third detection filter that are interconnected to one another. The quadrature signal minus the output of the three detection filters is taken as an intermediate signal. The intermediate signal is added to the output signal of the first detection filter as the input signal of the first detection filter; the intermediate signal is added to the output signal of the second detection filter as the input signal of the second detection filter; and the intermediate signal is added to the output signal of the third detection filter as the input signal of the third detection filter.

[0071] The first detection filter extracts positive sequence signal having the same frequency as the rotating electrical frequency of the motor rotor from the quadrature signal, and the first detection filter can be expressed as:

[00010]$F_1\left(s\right)=\frac{{?}_c}{s-j{?}_0+{?}_c}$

[0072] wherein, ?.sub.0 is the frequency of the positive sequence signal, ?.sub.c=k.sub.c*?.sub.0, k.sub.c=0.707.

[0073] The second detection filter is capable of extracting negative sequence signal having the same frequency as the rotating electrical frequency of the motor rotor from the quadrature signal, and the second detection filter can be expressed as:

[00011]$F_2\left(s\right)=\frac{{?}_c}{s+j{?}_0+{?}_c}$

[0074] The third detection filter is capable of extracting sideband signal near the positive sequence signal from the quadrature signal, and the third detection filter can be expressed as:

[00012]$F_3\left(s\right)=\frac{{?}_c}{s-j\left(1-1/p\right){?}_0+{?}_c}$

[0075] wherein, p is the number of pole pairs of the permanent magnet motor, and p=10.

[0076] (4) The amplitude of the negative sequence signals is extracted by means of phase-locked loops of a first synchronous reference system as a static eccentricity indicator, and the amplitude of the negative sequence signals is extracted by means of phase-locked loops of a second synchronous reference system as a dynamic eccentricity indicator.

[0077] (5) Finally, twice the ratio of the static eccentricity indicator to the amplitude of the positive sequence component is taken as a static eccentricity percentage; the ratio of the dynamic eccentricity indicator to the amplitude of the positive sequence component is taken as a dynamic eccentricity percentage, and the percentage value is taken as an eccentricity diagnosis quantity.

[0078] The foregoing descriptions are merely preferred specific implementations of the present invention, and are not intended to limit the protection scope of the present invention. Any equivalent replacements or changes made by a person skilled in the art according to the technical solutions of the present invention and the inventive concepts thereof within the technical scope disclosed in the present invention shall fall within the protection scope of the present invention.