阅读说明：本技术 一种基于线性霍尔的永磁电机偏心诊断方法及其检测系统 (Permanent magnet motor eccentricity diagnosis method based on linear Hall and detection system thereof ) 是由 花为 王宇辰 张超 刘凯 于 2021-09-08 设计创作，主要内容包括：本发明公开一种基于线性霍尔的永磁电机偏心诊断方法及其检测系统,属于发电、变电或配电的技术领域。首先将三个线性霍尔元件分别以相同的空间间隔安装在定子槽内；其次,通过数字信号处理器将三相线性霍尔输出的模拟信号转为为数字信号,并通过线性组合转化为正交信号；进而,采用带有谐波选择能力的复因数滤波器,从正交信号中提取负序信号和边带信号；然后,采用同步参考系锁相环提取负序信号的幅值、边带信号的幅值作为静态偏心指示量和动态偏心指示量；最后,在数字信号处理器内将上述指示量计算为代表偏心程度的百分比。本发明实现了低成本、高紧凑性、高精度的转子偏心检测,有效区分静态偏心和动态偏心程度,可应用于多种拓扑结构的电机。(The invention discloses a permanent magnet motor eccentricity diagnosis method based on linear Hall and a detection system thereof, belonging to the technical field of power generation, power transformation or power distribution. Firstly, respectively installing three linear Hall elements in a stator slot at the same space interval; secondly, converting analog signals output by the three-phase linear Hall into digital signals through a digital signal processor, and converting the digital signals into orthogonal signals through linear combination; further, a complex factor filter with harmonic selection capability is adopted to extract a negative sequence signal and a sideband signal from the orthogonal signal; then, extracting the amplitude of the negative sequence signal and the amplitude of the sideband signal by adopting a synchronous reference system phase-locked loop to serve as a static eccentricity indicating quantity and a dynamic eccentricity indicating quantity; finally, the indicated amount is calculated in the digital signal processor as a percentage representing the degree of eccentricity. The invention realizes the rotor eccentricity detection with low cost, high compactness and high precision, effectively distinguishes the static eccentricity and the dynamic eccentricity degree, and can be applied to motors with various topological structures.)

1. A permanent magnet motor eccentricity diagnosis method based on linear Hall is characterized in that a first linear Hall element, a second linear Hall element and a third linear Hall element are installed in a stator slot at equal intervals along the circumferential direction, the magnetic sensitive surfaces of the linear Hall elements are all opposite to a permanent magnet on the surface of a rotor, the output voltages of the three linear Hall elements are linearly combined to obtain an orthogonal signal containing a pair of orthogonal components and a direct current component, a positive sequence signal, a negative sequence signal and a sideband signal are extracted from the orthogonal signal, the amplitude of the negative sequence signal is extracted as a static eccentricity indicating quantity, the amplitude of the sideband signal is extracted as a dynamic eccentricity indicating quantity, and obtaining the static eccentricity percentage according to the ratio of the static eccentricity indicating quantity to the positive sequence signal amplitude, and obtaining the dynamic eccentricity percentage according to the ratio of the dynamic eccentricity indicating quantity to the positive sequence signal amplitude.

2. The linear hall-based permanent magnet motor eccentricity diagnosis method according to claim 1, wherein the expression for obtaining the quadrature signal comprising a pair of quadrature components and a dc component by linearly combining the output voltages of three linear hall elements is: h_αβ0＝T_APSH_αβ0，H_abcVector formed by output voltages of three linear Hall elements, H_abc＝[H_a,H_b,H_c]^T，H_aFor the second linear Hall element output voltage, H_bFor the first linear Hall element output voltage, H_cFor the third linear Hall element output voltage, H_αβ0For quadrature signals, H_αβ0＝[H_αH_β,H₀]^T，H_αAnd H_βIs a quadrature component, H₀Is a direct current component, T_APSIn the form of a matrix of linear combination coefficients, for two adjacent linear Hall elementsThe electrical angle of the gap.

3. The linear hall-based permanent magnet motor eccentricity diagnosis method according to claim 1, wherein the expression for extracting the positive sequence signal is as follows:F₁(s) is the expression of the positive sequence signal in the s domain, ω₀Is the frequency, omega, of the positive-sequence signal_cTo cut-off frequency, ω_c＝k_c*ω₀，k_cIs a positive number.

4. The linear hall-based permanent magnet motor eccentricity diagnosis method according to claim 1, wherein the negative sequence signal has an expression:F₂(s) is the expression of the negative sequence signal in the s domain, ω₀Is the frequency, omega, of the positive-sequence signal_cTo cut-off frequency, ω_c＝k_c*ω₀，k_cIs a positive number.

5. The linear hall-based permanent magnet motor eccentricity diagnosis method according to claim 1, wherein the expression for extracting the sideband signal is as follows:F₃(s) is the expression of the sideband signal in the s domain, ω₀Is the frequency, omega, of the positive-sequence signal_cTo cut-off frequency, ω_c＝k_c*ω₀，k_cIs positive number, and p is the pole pair number of the permanent magnet motor.

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

7. The linear hall-based eccentricity diagnosis method for permanent magnet motors according to any one of claims 1 to 6, wherein the method is applied to stator permanent magnet motors or rotor permanent magnet motors.

8. The utility model provides an eccentric detecting system of permanent-magnet machine based on linear hall which characterized in that includes:

the first linear Hall element is arranged in the stator slot, and the magnetic sensitive surface is opposite to the permanent magnet on the surface of the rotor;

a second linear Hall element installed in the stator slot and circumferentially spaced from the first linear Hall elementElectrical angle, the magnetic sensitive surface is opposite to the permanent magnet on the surface of the rotor;

a third linear Hall element installed in the stator slot and circumferentially spaced from the second linear Hall elementElectrical angle, the magnetic sensitive surface is opposite to the permanent magnet on the surface of the rotor; and a process for the preparation of a coating,

the digital signal processor is used for carrying out linear combination on the output voltages of the three linear Hall elements to obtain an orthogonal signal containing a pair of orthogonal components and a direct current component, extracting a positive sequence signal, a negative sequence signal and a sideband signal from the orthogonal signal, extracting the amplitude of the negative sequence signal as a static eccentricity indicating quantity, extracting the amplitude of the sideband signal as a dynamic eccentricity indicating quantity, obtaining a static eccentricity percentage according to the ratio of the static eccentricity indicating quantity to the amplitude of the positive sequence signal, and obtaining a dynamic eccentricity percentage according to the ratio of the dynamic eccentricity indicating quantity to the amplitude of the positive sequence signal.

9. The system of claim 8, wherein the digital signal processor comprises:

the linear combination unit receives the output voltages of the three linear Hall elements and outputs an orthogonal signal comprising a pair of orthogonal components and a direct current component;

the input end of the complex factor filter is connected with the output end of the linear combination unit, and a positive sequence signal, a negative sequence signal and a sideband signal are extracted from the orthogonal signal and then output;

the first synchronous reference system phase-locked loop receives the negative sequence signal output by the complex factor filter, extracts the amplitude of the negative sequence signal and outputs the negative sequence signal;

the second synchronous reference system phase-locked loop receives the sideband signal output by the complex factor filter, extracts the amplitude of the sideband signal and outputs the sideband signal; and a process for the preparation of a coating,

and the calculating unit is used for receiving the negative sequence signal amplitude and the sideband signal amplitude output by the complex factor filter, receiving the positive sequence signal output by the complex factor filter, calculating the ratio of the negative sequence signal amplitude to the positive sequence signal amplitude, outputting the static eccentricity percentage, calculating the ratio of the sideband signal amplitude to the positive sequence signal amplitude, and outputting the dynamic eccentricity percentage.

10. The system of claim 9, wherein the complex factor filter comprises:

the first input end of the first addition and subtraction combination module is connected with the orthogonal signal, the second input end of the first addition and subtraction combination module is connected with the output end of the fifth subtraction combination module, and the first addition and subtraction combination module outputs an intermediate signal obtained by removing a positive sequence signal, a negative sequence signal and a sideband signal from the orthogonal signal;

the first input end of the second addition and subtraction combination module is connected with the output end of the first addition and subtraction combination module, the second input end of the second addition and subtraction combination module is connected with the output end of the first detection filter, and the second addition and subtraction combination module outputs the accumulation result of the intermediate signal and the positive sequence signal;

a third addition and subtraction combination module, the first input end of which is connected with the output end of the first addition and subtraction combination module, the second input end of which is connected with the output end of the second detection filter, and the third addition and subtraction combination module outputs the accumulation result of the intermediate signal and the negative sequence signal;

a fourth addition and subtraction combination module, the first input end of which is connected with the output end of the first addition and subtraction combination module, the second input end of which is connected with the output end of the third detection filter, and the fourth addition and subtraction combination module outputs the accumulation result of the intermediate signal and the sideband signal;

the input end of the first detection filter is connected with the output end of the second add-subtract combination module and outputs a positive sequence signal;

the input end of the second detection filter is connected with the output end of the third add-subtract combination module and outputs a negative sequence signal; and a process for the preparation of a coating,

and the input end of the third detection filter is connected with the output end of the fourth add-subtract combination module and outputs a sideband signal.

Technical Field

The invention relates to an eccentricity detection technology of a permanent magnet motor, in particular discloses a permanent magnet motor eccentricity diagnosis method based on linear Hall and a detection system thereof, and belongs to the technical field of power generation, power transformation or power distribution.

Background

Rotor eccentricity is one of the most common faults of the motor, and the rotor eccentricity in a permanent magnet synchronous motor directly causes the length of an air gap to be asymmetric, so that the magnetic tension between a stator and a rotor is unbalanced. The magnetic tension imbalance may further cause other electrical and mechanical problems, such as current load imbalance of different phases, noise and vibration. The continuous operation of the permanent magnet synchronous motor can cause bearing wear, aggravation of eccentricity and even bearing fracture. Therefore, monitoring and diagnosis of rotor eccentricity is essential in the practical application of permanent magnet synchronous machines.

The method is the most direct detection method for judging the eccentricity of the rotor by detecting the distribution condition of the magnetic field in the permanent magnet motor. The invention patent with the patent number CN107192947A discloses a diagnosis method for failure of a permanent magnet synchronous motor based on magnetic field monitoring, wherein coil failure values corresponding to coils wound on all stator teeth of the permanent magnet synchronous motor form two peak values, and then the failure type is determined to be an eccentric failure. The invention patent with the patent number of CN109541461A discloses a permanent magnet synchronous motor eccentric fault diagnosis method based on magnetic field distribution monitoring, wherein a coil is wound on each stator tooth, and harmonic distribution is further analyzed by deducing flux linkage values through coil voltage when a rotor rotates, so that the identification of the type of the eccentric fault can be realized, and the degree and the direction of the eccentric fault can be accurately identified. According to the method for detecting eccentricity based on the extra winding, the voltage amplitude of the extra winding is in direct proportion to the rotating speed, so that the amplitude of an output signal is greatly changed under different rotating speeds, data acquisition is difficult, and the hardware cost is increased.

In order to realize the decoupling of the signal amplitude and the rotating speed, a linear Hall sensor can be used as a magnetic density detection element. The invention patent with the patent number of CN108614212A discloses a decoupling diagnosis method and a device for eccentricity and demagnetization faults of a hub motor, wherein 2N Hall sensors are arranged in two stator tooth grooves which are radially symmetrical to a central shaft of the hub motor, N Hall sensors are arranged in each stator tooth groove at equal intervals along the axial direction, the Hall sensors in the two radially symmetrical stator tooth grooves are on the same diameter line, and the 2N Hall sensors are connected with an upper computer through a multi-path voltage signal acquisition box. The method can accurately identify the fault according to the fault characteristic value, and achieves the purpose of decoupling diagnosis of the eccentricity and demagnetization coupling faults, however, the method cannot realize accurate detection under a specific static eccentricity state. The invention patent with the patent number of CN113094952A discloses a static eccentricity detection method of a permanent magnet motor based on a stray magnetic field, the use of a neural network model enables the calculation amount of eccentricity detection to be increased, and the error between the neural network model and the actual motor parameter enables the robustness of the eccentricity detection to be lower and the calculation amount to be larger. In addition, the above detection methods cannot simultaneously realize the eccentric detection of the rotor permanent magnet type motor and the stator permanent magnet type motor.

The method aims to accurately and rapidly detect and separate the static eccentric detection amount and the dynamic eccentric detection amount in the permanent magnet synchronous motor by reasonably installing the linear Hall element and designing the eccentric detection algorithm with universality on the permanent magnet synchronous motors with different topologies.

Disclosure of Invention

The invention aims to provide a permanent magnet motor eccentricity diagnosis method and a detection system thereof based on linear Hall, wherein a linear Hall sensor for detecting radial magnetic density is arranged in a stator slot of a permanent magnet synchronous motor, and the linear Hall output signal is processed to obtain the real-time static eccentricity detection amount and the real-time dynamic eccentricity detection amount of a rotor, so that the invention aims at realizing low-cost non-invasive real-time eccentricity detection of permanent magnet motors with various topologies, and the technical problems that the existing permanent magnet motor eccentricity detection technology is difficult in data acquisition, high in hardware cost and incapable of realizing simultaneous detection of static eccentricity and dynamic eccentricity of motors with different topologies

The invention adopts the following technical scheme for realizing the aim of the invention:

the invention provides a permanent magnet motor eccentricity diagnosis method based on linear Hall, which is realized by a detection system consisting of three linear Hall elements and a digital signal processor, wherein the three linear Hall elements are arranged in a stator slot at the same interval. The magnetic sensitive surfaces of the three Hall elements are opposite to the surface of the rotor with the permanent magnet; among the three linear Hall elements, the first linear Hall element is mounted on the statorAt any position in the groove, along the circumferential direction, the second linear Hall has a phase difference from the first linear HallElectrical angle; third linear Hall phase difference from second linear Hall phase differenceElectrical angle. Then, the degree of eccentricity of the motor is calculated from the output voltage signals of the three linear hall elements.

The eccentricity diagnosis method for calculating the eccentricity degree of the motor according to the output voltage signals of the three linear Hall elements specifically comprises the following steps:

(1) the digital signal processor converts the output voltage signals of the three linear Hall elements into digital signals through an analog-to-digital converter, and the digital signals are three-phase signals.

(2) The three-phase signal is preprocessed into quadrature signals with harmonics.

It is assumed here that the signals output by the three linear hall are H_abc＝[H_a,H_b,H_c]^T，H_aThe signal comes from a second linear Hall element, H_bThe signal coming from the first linear Hall element, H_cThe signal comes from the third linear hall element. The pretreatment process is H_abcMapping the three-phase signal to a two-phase stationary coordinate system, and processing the orthogonal signal to be H_αβ0＝[H_αH_β,H₀]^T. Wherein H_αAnd H_βIs a quadrature component, H₀Is a direct current component. The model of the above linear combination is:

H_αβ0＝T_APSH_abc

(3) a complex factor filter with harmonic selection capability is used to extract the negative sequence signal and sideband signal from the quadrature signal.

The complex factor filter is formed by interconnecting a first detection filter, a second detection filter and a third detection filter. Quadrature signal H_αβ0The outputs of the three detection filters are subtracted as the intermediate signal. Adding the intermediate signal and the output signal of the first detection filter to form an input signal of the first detection filter, wherein the output signal of the first detection filter is a positive sequence signal; adding the intermediate signal and the output signal of the second detection filter to be used as the input signal of the second detection filter, wherein the output signal of the second detection filter is a negative sequence signal; the intermediate signal is added to the output signal of the third detection filter as the input signal of the third detection filter, and the output signal of the third detection filter is the sideband signal.

The first detection filter may extract a positive sequence signal having the same electrical frequency as the rotating frequency of the motor rotor from the quadrature signal, and the first detection filter may be expressed as:

wherein, ω is₀The frequency of the positive sequence signal is the same as the rotating electrical frequency of the motor rotor; omega_c＝k_c*ω₀，k_cIs positive and can be used to adjust the detection filter bandwidth, omega_cIs the cut-off frequency.

The second detector may extract a negative sequence signal opposite to the electrical frequency of rotation of the motor rotor from the quadrature signal, and may be represented as:

the third detector may extract sideband signals near the positive sequence signal from the quadrature signal, and the third detector may be represented as:

wherein p is the pole pair number of the permanent magnet motor.

(4) And extracting the amplitude of the negative sequence signal as a static eccentricity indicator by adopting a first synchronous reference system phase-locked loop, and extracting the amplitude of the sideband signal as a dynamic eccentricity indicator by adopting a second synchronous reference system phase-locked loop.

(5) Twice the ratio of the magnitude of the static eccentricity indicator to the positive sequence component as the static eccentricity percentage; and the ratio of the dynamic eccentricity indicating quantity to the amplitude of the positive sequence component is taken as a dynamic eccentricity percentage, and the static eccentricity percentage value and the dynamic eccentricity percentage value are taken as eccentricity diagnostic quantities.

By adopting the technical scheme, the invention has the following beneficial effects:

(1) according to the invention, the Hall sensors are circumferentially and equidistantly arranged in the stator slot to detect the radial magnetic densities of the permanent magnet motors with different topological structures, the Hall sensors output data are sequentially subjected to linear combination, complex factor filtering and phase locking processing to quickly detect the real-time eccentric amount, and the static eccentric detection amount and the dynamic eccentric detection amount are effectively separated, so that the defect that the static eccentric amount cannot be accurately detected in a specific state by the existing eccentric detection method is overcome, the high-compactness and low-cost eccentric detection of the permanent magnet motors with multiple topological structures is realized, and the separation of the static eccentric amount and the dynamic eccentric amount is realized.

(2) The permanent magnet motor eccentricity diagnosis scheme disclosed by the invention can be realized by using a non-invasive detection system consisting of the Hall sensor and the digital signal processor with lower cost, and compared with the permanent magnet motor eccentricity diagnosis scheme through an additional winding, the permanent magnet motor eccentricity diagnosis scheme solves the problem of difficult data acquisition and reduces the hardware cost.

Drawings

Fig. 1 is a block diagram of a rotor permanent magnet motor eccentricity detection system based on linear hall according to the present invention.

Fig. 2 shows a rotor permanent magnet motor according to embodiment 1.

Fig. 3 shows a stator permanent magnet motor according to embodiment 2.

Fig. 4 is a block diagram of a complex factor filter in the linear hall-based permanent magnet motor eccentricity diagnosis method and the detection system thereof according to the present invention.

Fig. 5 is a waveform diagram of three-phase signals output by three linear hall elements and their corresponding quadrature signals, negative sequence signals, and sideband signals in embodiment 1.

The reference numbers in the figures illustrate: 1. first linear hall element, 2, second linear hall element, 3, third linear hall element, 4, the motor under test, 6, linear combination unit 8, complex factor filter, 13, digital signal processor, 14, first add subtract mode combination module, 15, second add subtract mode combination module, 16, third add subtract mode combination module, 17, fourth add subtract mode combination module, 18, fifth subtract mode combination module.

Detailed Description

The technical scheme of the invention is explained in detail in the following with reference to the attached drawings.

Example 1: eccentricity diagnosis rotor permanent magnet motor based on linear Hall element

Referring to fig. 1, the invention provides a permanent magnet motor eccentricity diagnosis method based on linear hall and a detection system thereof, wherein the detection system comprises: a first linear Hall element 1, a second linear Hall element 2, a third linear Hall element 3 which are arranged in the stator slot of the tested motor 4 and a digital signal processor 13 which processes the output voltage of the Hall elements. The tested motor 4 is a three-phase 18-slot 20-pole rotor permanent magnet motor as shown in fig. 2, three linear Hall elements are arranged in stator slots and are sequentially spaced by 2 stator slot pitches, and the magnetic sensitive surfaces of the Hall elements are opposite to the surface of a rotor with a permanent magnet; among the three linear Hall elements, the first linear Hall element 1 is arranged at any notch of the stator, and along the circumferential direction, the second linear Hall element 2 has a phase difference from the first linear Hall element 1Electrical angle; the third linear Hall 3 has a phase difference from the second linear Hall 2Electrical angle.

And when the rotor rotates at a constant speed in the positive direction by taking the anticlockwise direction as the positive direction: the first linear hall element 1 and the second linear hall element 2 output voltage signals with an electrical angle phase differenceThe second linear hall element 2 and the third linear hall element 3 output voltage signals with an electrical angle phase difference

Three linear hall elements are connected to a digital signal processor 13. The supply voltage for the digital signal processor 13 is 3.3 volts. H_aThe signal comes from the second linear Hall element 2, H_bThe signal comes from the first linear Hall element 1, H_cThe signal comes from the third linear hall element 3, which outputs an analog voltage of 0-3.3V. The output voltage signals of the three linear hall elements are converted into three-phase raw digital signals, denoted as H, in the digital signal processor 13_abc＝[H_a,H_b,H_c]^T。

The three phase signals are linearly combined as shown in the following formula:

H_αβ0＝T_APSH_abc

wherein:

the orthogonal signal obtained after linear combination processing is H_αβ0＝[H_αH_β,H₀]^T。

A complex factor filter with harmonic selection capability is used to extract the negative sequence signal and sideband signal from the quadrature signal.

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 interconnected. The quadrature signal subtracts the outputs of the three detection filters as an intermediate signal, and the intermediate signal is processed by the first add-subtract combination module 14, and the outputs of the three detection filters are added by the fifth subtract combination module 18 and then sent to the first add-subtract 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 by the second add-subtract 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, and the addition and subtraction combination module 16 completes the addition and subtraction; the intermediate signal is added to the output signal of the third detection filter as the input signal of the third detection filter by the fourth add-subtract combination module 17.

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

wherein psi₀For the frequency of the positive-sequence signal, #_c＝k_c*ω₀，k_c＝0.707。

The second detection filter extracts a negative sequence signal opposite to the electric frequency of rotation of the motor rotor from the quadrature signal, and can be expressed as:

the third detection filter extracts the sideband signal around the positive sequence signal from the quadrature signal, and can be expressed as:

wherein, p is the pole pair number of the permanent magnet motor, and p is 10.

(4) And extracting the amplitude of the negative sequence signal as a static eccentricity indicator by adopting a first synchronous reference system phase-locked loop, and extracting the amplitude of the sideband signal as a dynamic eccentricity indicator by adopting a second synchronous reference system phase-locked loop.

(5) Finally, twice the ratio of the magnitude of the static eccentricity indicator to the positive sequence component is taken as the static eccentricity percentage; the ratio of the magnitude of the dynamic eccentricity indicator to the magnitude of the positive sequence component is taken as the dynamic eccentricity percentage, which is taken as the eccentricity diagnostic.

Simulations are performed below in conjunction with specific eccentricity conditions, and results referring to fig. 5, three-phase signals, quadrature signals, negative sequence signals, and sideband signals are shown, respectively. The amplitude of the negative sequence signal extracted by the phase-locked loop of the first synchronous reference system is shown by a dotted line; the amplitude of the extracted sideband signal of the second synchronous reference frame phase-locked loop is shown by the dotted line.

(1) Before 0.3s, the tested motor 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; the sideband component is 0.

(2) And the signal frequency is 600Hz within 0.3-0.7 s, the tested motor 4 is in a static eccentric state, and the static eccentric distance is 0.3 times of the length of the air gap. The amplitude of the negative sequence signal output by the complex factor filter rises and stabilizes to a constant value; the sideband signal amplitude rises first and then converges to 0. Since dynamic eccentricity is a static eccentricity that changes with time, a malfunction occurs immediately when the static eccentricity occurs, but the predicted value of dynamic eccentricity converges to the actual value in a short time.

(3) And the signal frequency is 600Hz within 0.7-1.1 s, the tested motor 4 is in a mixed eccentric state, the static eccentric distance is 0.3 times of the air gap length, and the dynamic eccentric distance is 0.2 times of the air gap length. The amplitude of the negative sequence signal output by the complex factor filter is kept basically unchanged; the amplitude of the sideband signal rises and remains substantially constant.

(3) The tested motor 4 is in a mixed eccentric state within 1.1-1.5 s, the static eccentric distance is 0.3 times of the air gap length, the dynamic eccentric distance is 0.2 times of the air gap length, and the rotating speed is changed from 600Hz to 200 Hz. The eccentric detection result is basically unchanged, and the system is suitable for different rotating speeds.

Finally, twice the ratio of the magnitude of the static eccentricity indicator to the positive sequence component is 30% static eccentricity percentage; the ratio of the magnitude of the dynamic eccentricity indicator to the positive sequence component was taken as the dynamic eccentricity percentage 20%.

Example 2: stator permanent magnet motor eccentricity diagnosis based on linear Hall element

Referring to fig. 1, the invention provides a method for diagnosing eccentricity of a permanent magnet motor based on linear hall and a detection system thereof, wherein a tested motor 4 is a three-phase 12-slot 10-pole stator permanent magnet type motor as shown in fig. 3. Three linear Hall elements are installed in stator slots and are sequentially spaced by 1 stator slot pitch. The magnetic sensitive surfaces of the Hall elements are opposite to the surfaces of the salient poles of the rotor with the permanent magnets; among the three linear Hall elements, the first linear Hall element 1 is arranged at any notch of the stator, and along the uniform direction, the second linear Hall element 2 has a phase difference from the first linear Hall element 1Electrical angle; the third linear Hall 3 has a phase difference from the second linear Hall 2Electrical angle.

And when the rotor rotates at a constant speed in the positive direction by taking the anticlockwise direction as the positive direction: the first linear hall element 1 and the second linear hall element 2 output voltage signals with an electrical angle phase differenceThe second linear hall element 2 and the third linear hall element 3 output voltage signals with an electrical angle phase difference

Three linear hall elements are connected to a digital signal processor 13. The supply voltage for the digital signal processor 13 is 3.3 volts. H_aThe signal comes from the second linear Hall element 2, H_bThe signal comes from the first linear Hall element 1, H_cThe signal comes from the third linear hall element 3 and outputs an analog voltage of 0-3.3V. Converting the output voltage signals of three linear Hall elements into three-phase original digital signals in a digital signal processor, wherein the three-phase original digital signals are represented as H_abc＝[H_a,H_b,H_c]^T。

The three-phase signals are linearly combined as follows:

H_αβ0＝T_APSH_abc

wherein:

the processed orthogonal signal is H_αβ0＝[H_αH_β,H₀]^T。

A complex factor filter with harmonic selection capability is used to extract the negative sequence signal and sideband signal from the quadrature signal.

The complex factor filter is formed by interconnecting a first detection filter, a second detection filter and a third detection filter. The quadrature signal is subtracted from the outputs of the three detection filters as an intermediate signal. The intermediate signal is added to the output signal of the first detection filter as an input signal of the first detection filter; adding the intermediate signal and the output signal of the second detection filter as an input signal of the second detection filter; the intermediate signal is added to the output signal of the third detection filter as an input signal of the third detection filter.

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

wherein, ω is₀Is the frequency, omega, of the positive-sequence signal_c＝k_c*ω₀，k_c＝0.707。

The second detection filter may extract a negative sequence signal opposite to the electric frequency of rotation of the motor rotor from the quadrature signal, and the second detection filter may be expressed as:

the third detection filter may extract a sideband signal near the positive sequence signal from the quadrature signal, and the third detection filter may be expressed as:

wherein, p is the pole number of the permanent magnet motor, and p is 10.

(4) And extracting the amplitude of the negative sequence signal as a static eccentricity indicator by adopting a first synchronous reference system phase-locked loop, and extracting the amplitude of the sideband signal as a dynamic eccentricity indicator by adopting a second synchronous reference system phase-locked loop.

(5) Finally, twice the ratio of the magnitude of the static eccentricity indicator to the positive sequence component is taken as the static eccentricity percentage; the ratio of the magnitude of the dynamic eccentricity indicator to the magnitude of the positive sequence component is taken as the dynamic eccentricity percentage, which is taken as the eccentricity diagnostic.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can make equivalent substitutions or changes to the technical solution according to the inventive concept of the present invention after seeing the technical solution disclosed in the present invention.