Axial skewed pole motor eccentricity detection method based on asymmetric layered Hall

Abstract

The invention provides an axial skewed pole motor eccentricity detection method based on asymmetric layered Hall, and the method comprises the following steps: respectively installing a first group of linear Hall sensors and a second group of linear Hall sensors on a first axial layer and a second axial layer of a stator notch of an axial skewed pole motor in an asymmetric manner; after analog-to-digital conversion is carried out on the voltage signals detected by the linear Hall sensor, a pair of orthogonal third harmonic sinusoidal signals is obtained through grouping signal superposition, and the eccentric direction is determined; and based on a complex factor filter and a synchronous reference system phase-locked loop, extracting amplitudes of a positive sequence signal, a negative sequence signal and a sideband signal from the third harmonic sinusoidal signal, and further calculating a static eccentricity rate and a dynamic eccentricity rate. According to the axial skewed pole motor eccentricity detection method, two groups of linear Hall sensors are mounted in a layered and asymmetric manner, so that the eccentricity detection sensitivity and precision are effectively improved, the eccentricity state change in the motor operation process can be quickly responded, and the dynamic and static eccentricity rates and the eccentricity direction are output.

Description

Technical Field

[0001] This invention relates to motor testing technology, and more specifically, to a method for detecting eccentricity in axially skewed pole motors based on asymmetric layered Hall effect sensors. Background Technology

[0002] In the field of motor technology, rotor eccentricity monitoring and diagnosis are essential for the practical application of permanent magnet synchronous motors. Chinese invention patent CN113686237A discloses an eccentricity diagnosis method for permanent magnet motors. First, three linear Hall sensors are installed in the stator slots with equal spatial intervals. Second, a digital signal processor converts the analog signals output by the three-phase linear Hall sensors into digital signals, and then converts them into quadrature signals through linear combination. Next, a complex factor filter with harmonic selection capability is used to extract the negative sequence signal and sideband signal from the quadrature signal. Then, a synchronous reference system phase-locked loop is used to extract the amplitude of the negative sequence signal and the amplitude of the sideband signal as static and dynamic eccentricity indicators. Finally, the digital signal processor calculates these indicators as a percentage representing the degree of eccentricity. By installing linear Hall sensors in the stator slots of the permanent magnet synchronous motor and processing the linear Hall output signals, real-time static and dynamic eccentricity detection values ​​of the rotor are obtained.

[0003] A skewed-pole motor is a new type of permanent magnet motor that uses permanent magnets as its rotor. It counteracts cogging torque and electromagnetic vibration by axially skewing or segmenting the rotor core. However, this design makes the motor significantly more sensitive to eccentricity faults than typical permanent magnet motors. When skewed-pole motors become eccentric, their axially distributed magnetic field complexly superimposes the effects of air gap unevenness in three-dimensional space. Different eccentricity directions directly alter the electromagnetic force's action mode: if the eccentricity direction is parallel to the rotor's skew direction, it excites axial torsional vibration; if perpendicular, it intensifies radial vibration. This directional vibration not only amplifies noise but can also trigger casing resonance, threatening structural safety. Electromagnetic performance is also constrained by the eccentricity direction. The originally optimized back EMF waveform of the skewed-pole motor will be distorted by even-order harmonics due to eccentricity, and the distorted phase shifts with the eccentricity direction, leading to a decrease in magnetic field orientation control accuracy. Torque pulsation exhibits directional asymmetry—the peak pulsation at a specific angle is enhanced due to the difference in eccentricity direction, directly affecting the smoothness of high-end applications. In terms of fault diagnosis, the segmented rotor structure with skewed poles means that eccentricity may originate from machining or assembly errors in a particular segment, requiring directional identification to pinpoint the problem. Ignoring directional characteristics can lead to misjudgments of the fault severity through conventional vibration or current spectrum analysis. For example, the amplitude of the dynamic eccentric current sideband is directionally sensitive at specific harmonic orders; monitoring only the amplitude can miss crucial information.

[0004] When the eccentricity diagnosis method of permanent magnet motor is directly applied to skewed pole motor, the following problems may occur due to the special structure of the skewed pole rotor: if the number of linear Hall sensors is insufficient or symmetrically distributed (such as only 3 120° intervals), when the static eccentricity direction coincides with the position of a certain sensor, the sensor will capture the extreme magnetic flux density value. If the algorithm only averages the signals of each sensor, it will mask the direction information.

[0005] Therefore, it is crucial to provide a detection method that can detect both the degree and direction of eccentricity of a skewed motor. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of existing technologies by providing an axial skewed-pole motor eccentricity detection method based on asymmetric layered Hall sensors. By employing layered and asymmetric Hall sensor installation, the sensitivity and robustness of skewed-pole motor eccentricity detection are improved, and the direction and degree of eccentricity during the dynamic process of the skewed-pole motor are detected.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The first aspect of this invention provides a method for detecting eccentricity in an axially skewed pole motor based on asymmetric layered Hall effect sensors, comprising the following steps: Step 1: Install a first set of linear Hall sensors on the first axial layer of the stator slot of the axial skewed pole motor. The first set of linear Hall sensors includes a first linear Hall sensor, a second linear Hall sensor and a third linear Hall sensor that are located on the circumference of the first radius and are equally spaced along the circumference. A second set of linear Hall sensors is installed in the second axial layer of the stator slot of the axial skewed pole motor. The second set of linear Hall sensors includes a fourth linear Hall sensor, a fifth linear Hall sensor, and a sixth linear Hall sensor that are located on the circumference of the second radius and are equally spaced along the circumference. The first radius is not equal to the second radius. The magnetic sensing surface of any linear Hall sensor is opposite to the surface of the permanent magnet on the rotor, and the second set of linear Hall sensors is staggered with the first set of linear Hall sensors to form a complementary detection area. Step 2: After performing analog-to-digital conversion on the voltage signals output from the two sets of linear Hall sensors, the grouped signals are then superimposed to obtain a pair of orthogonal third harmonic sinusoidal signals V. 3α and V 3β ; Step 3, based on the third harmonic sinusoidal signal V 3α and V 3β The fundamental amplitude determines the direction of eccentricity; Step 4: Based on the complex factor filter and the synchronous reference frame phase-locked loop, the quadrature third harmonic sinusoidal signal V is obtained. 3α and V 3βThe amplitudes of the positive-sequence signal, negative-sequence signal, and sideband signal are extracted. The static eccentricity is obtained based on the ratio of the negative-sequence signal amplitude to the positive-sequence signal amplitude, and the dynamic eccentricity is obtained based on the ratio of the sideband signal amplitude to the positive-sequence signal amplitude.

[0008] By asymmetrically installing two sets of linear Hall sensors on the upper and lower layers of the stator slot to detect the direction of the magnetic field when the axial pole motor is eccentric, the problem of blind zone detection caused by symmetrically installed Hall elements due to motor eccentricity is overcome. Furthermore, the dynamic and static eccentricity rate and eccentricity direction of the motor can be accurately detected based on the axial magnetic field of the Hall signals from the upper and lower layers.

[0009] As a preferred embodiment of the present invention, when performing grouped signal superposition on the two sets of voltage signals after analog-to-digital conversion, a grouped superposition model is adopted: ; V D1 The digital signal, V, is the voltage signal output by the first linear Hall sensor after analog-to-digital conversion. D2 The digital signal, V, is the voltage signal output by the second linear Hall sensor after analog-to-digital conversion. D3 The digital signal, V, is the voltage signal output by the third linear Hall sensor after analog-to-digital conversion. D4 The voltage signal output by the fourth linear Hall sensor is converted into a digital signal by analog-to-digital conversion, V D5 The digital signal, V, is the voltage signal output by the fifth linear Hall sensor after analog-to-digital conversion. D6 The digital signal, U, is the voltage signal output by the sixth linear Hall sensor after analog-to-digital conversion. m1 For a sinusoidal signal V 3α The amplitude of the third harmonic, U m2 For a sinusoidal signal V 3β The amplitude, θ is the actual electrical angle of the rotor, 3θ r For V 3α V 3β The electrical angle difference between them.

[0010] As a preferred technical solution of the present invention, when the third harmonic V obtained by the first set of linear Hall sensors... 3α amplitude U m1 Greater than the third harmonic V obtained by the second set of linear Hall sensors 3β amplitude U m2 At that time, the first axial layer is eccentric, and the third harmonic V obtained by the second set of linear Hall sensors... 3β amplitude U m2 Greater than the third harmonic V obtained by the first set of linear Hall sensors 3α amplitude U m1 Then the second axial layer is eccentric.

[0011] As a preferred embodiment of the present invention, the first set of linear Hall sensors is located on the circumference of the first radius and is uniformly arranged with an electrical angle of equal N1 along the circumference; the second set of linear Hall sensors is located on the circumference of the second radius and is uniformly arranged with an electrical angle of equal N1 along the circumference; the second set of linear Hall sensors is offset from the first set of linear Hall sensors by an electrical angle of N2. Where N1=iP r M / P s ; i is the harmonic order, P s It is the number of slots, P r It is the pole number, and M is the number of teeth between any two slots; If the third harmonic sinusoidal signal V 3α and V 3β If they are orthogonal, then θ r =2kπ±π / 6, k=0,1,2,...; Given the first radius, according to θ r The second radius, θ, is obtained by calculating the piecewise function expression. r The piecewise function expression is: ; Where r2 is the second radius, R1 is the inner diameter of the rotor of the axial skewed motor, R3 is the outer diameter of the rotor of the axial skewed motor, R2 is the radius of the center of symmetry with the skewed permanent magnet, k1 is the slope of the skewed magnet in the R1-R2 segment, and k2 is the slope of the skewed magnet in the R2-R3 segment.

[0012] As a preferred embodiment of the present invention, the complex factor filter is composed of a first detector filter, a second detector filter, and a third detector filter interconnected. Orthogonal third harmonic sinusoidal signal V 3α and V 3β The outputs of the three detector filters are subtracted to obtain the intermediate signal; The intermediate signal is added to the output signal of the first detector filter to serve as the input signal of the first detector filter. The first detector filter receives the orthogonal third harmonic sinusoidal signal V. 3α and V 3β Extract the positive-sequence signal that has the same rotational frequency as the motor rotor. The expression for the positive-sequence signal is: ; The intermediate signal is added to the output signal of the second detector filter to serve as the input signal of the second detector filter. The second detector filter receives the orthogonal third harmonic sinusoidal signal V. 3α and V 3β Extract the negative sequence signal that is opposite to the electric frequency of the motor rotor rotation. The expression for the negative sequence signal is: ; The intermediate signal is added to the output signal of the third detector filter to serve as the input signal of the third detector filter. The third detector filter receives the orthogonal third harmonic sinusoidal signal V. 3α and V 3β The sideband signal is extracted from it, and the expression for the sideband signal is: ; In the formula, s is the input signal, p is the number of pole pairs of the permanent magnet motor, ω0 is the frequency of the positive sequence signal, and ω c ω is the cutoff frequency. c =k c ×ω0,k c It is a positive number.

[0013] As a preferred embodiment of the present invention, the synchronous reference system phase-locked loop includes a first synchronous reference system phase-locked loop and a second synchronous reference system phase-locked loop. The first synchronous reference system phase-locked loop is used to receive the negative sequence signal and extract the amplitude of the negative sequence signal to calculate the static eccentricity. The second synchronous reference system phase-locked loop is used to receive the sideband signal and extract the amplitude of the sideband signal to calculate the dynamic eccentricity.

[0014] A second aspect of the present invention provides an eccentricity detection system for an axially skewed pole motor, comprising: Voltage signal acquisition module: A first set of linear Hall sensors is installed in the first axial layer of the stator slot of the axial skewed pole motor, which includes a first linear Hall sensor, a second linear Hall sensor and a third linear Hall sensor located on the circumference of the first radius and equally spaced along the circumference. A second set of linear Hall sensors is installed in the second axial layer of the stator slot of the axial skewed pole motor. The second set of linear Hall sensors includes a fourth linear Hall sensor, a fifth linear Hall sensor, and a sixth linear Hall sensor that are located on the circumference of the second radius and are equally spaced along the circumference. The first radius is not equal to the second radius. The magnetic sensing surface of any linear Hall sensor is opposite to the surface of the permanent magnet on the rotor, and the second set of linear Hall sensors is staggered with the first set of linear Hall sensors to form a complementary detection area. Digital signal processor module: After performing analog-to-digital conversion on the voltage signals output from two sets of linear Hall sensors, the grouped signals are then superimposed to obtain a pair of orthogonal third harmonic sinusoidal signals V. 3α and V 3β ; Based on the third harmonic sinusoidal signal V 3α and V 3β The fundamental amplitude determines the direction of eccentricity; Based on a complex factor filter and a synchronous reference frame phase-locked loop, the quadrature third harmonic sinusoidal signal V... 3α and V 3βThe amplitudes of the positive-sequence signal, negative-sequence signal, and sideband signal are extracted. The static eccentricity is obtained based on the ratio of the negative-sequence signal amplitude to the positive-sequence signal amplitude, and the dynamic eccentricity is obtained based on the ratio of the sideband signal amplitude to the positive-sequence signal amplitude.

[0015] This invention has outstanding substantive features and significant progress compared to the prior art. Specifically, This invention adapts to the axial layered structure of segmented skew-pole motors. The structure is divided based on the rotor's inner diameter, outer diameter, and the radius of the symmetrical center of the permanent magnet with skew poles. By differentiating the distribution of these characteristic radii, spatially independent first and second axial layers are formed, and the two axial layers are spaced apart in the axial direction in a double-layer structure. Based on this structure, this invention has the following beneficial effects: (1) By arranging two sets of linear Hall sensors in an asymmetric layer, magnetic field distortion features can be captured from different spatial angles, avoiding the masking of information in a single direction and significantly improving the accuracy of eccentric direction identification. (2) It can simultaneously acquire magnetic field signals at different axial positions. Through layered comparative analysis, it can amplify the magnetic field differences caused by eccentricity, effectively improving the detection sensitivity of small eccentricity. Combined with grouped signal superposition and complex factor filtering, it can further reduce noise interference and improve the quantification accuracy of dynamic and static eccentricity. (3) Through the collaborative workflow of analog-to-digital conversion, group signal superposition, filtering and synchronous reference system phase-locked loop processing, it can quickly respond to the changes in eccentricity during motor operation, output eccentricity and eccentricity direction, meet the monitoring needs under dynamic motor operation conditions, and provide timely data support for fault early warning. Attached Figure Description

[0016] Figure 1 The flowchart shows the eccentricity detection method for axial skewed pole motors based on asymmetric layered Hall effect proposed in this invention. Figure 2 This is a module connection diagram of the axial skewed pole motor eccentricity detection system based on asymmetric layered Hall effect proposed in this invention. Figure 3 This is a block diagram of the detector filter proposed in this invention; Figure 4 This is a schematic diagram of the axial skew pole flux permanent magnet motor proposed in this invention; Figure 5 The Hall signal output by the linear Hall sensor proposed in this invention; Figure 6 The orthogonal signals corresponding to the group superposition proposed in this invention; Figure 7 This invention provides the positive-order signal extracted from orthogonal signals. Figure 8This invention provides a negative-order signal extracted from orthogonal signals. Figure 9 This invention provides the sideband signal extracted from orthogonal signals.

[0017] In the diagram: 1. First linear Hall sensor; 2. Second linear Hall sensor; 3. Third linear Hall sensor; 4. Fourth linear Hall sensor; 5. Fifth linear Hall sensor; 6. Sixth linear Hall sensor; 7. Stator slot; 8. Permanent magnet; 9. Stator tooth; 10. Annular winding; 11. Digital signal processor; 12. First detector; 13. Second detector; 14. Third detector; 15. Positive sequence signal; 16. Negative sequence signal; 17. Sideband signal. Detailed Implementation

[0018] The technical solution of the present invention will be further described in detail below through specific embodiments.

[0019] Example 1 like Figure 1 As shown, this embodiment provides a method for detecting eccentricity in an axially skewed pole motor based on asymmetric layered Hall effect sensors, including the following steps: Step 1: Install a first set of linear Hall sensors on the first axial layer of the stator slot 7 of the axial skewed pole motor. The first set of linear Hall sensors includes a first linear Hall sensor 1, a second linear Hall sensor 2 and a third linear Hall sensor 3, which are located on the circumference of the first radius and are equally spaced along the circumference. A second set of linear Hall sensors is installed in the second axial layer of the stator slot of the axial skewed pole motor. The sensor includes a fourth linear Hall sensor 4, a fifth linear Hall sensor 5 and a sixth linear Hall sensor 6, which are located on the circumference of the second radius and are equally spaced along the circumference. The first radius is not equal to the second radius. The magnetic sensing surface of any linear Hall sensor is opposite to the surface of the permanent magnet 8 on the rotor, and the second set of linear Hall sensors is staggered with the first set of linear Hall sensors to form a complementary detection area. Step 2: After performing analog-to-digital conversion on the voltage signals output from the two sets of linear Hall sensors, the grouped signals are then superimposed to obtain a pair of orthogonal third harmonic sinusoidal signals V. 3α and V 3β ; Step 3, based on the third harmonic sinusoidal signal V 3α and V 3β The fundamental amplitude determines the direction of eccentricity; Step 4: Based on the complex factor filter and the synchronous reference frame phase-locked loop, the quadrature third harmonic sinusoidal signal V is obtained. 3α and V 3βThe amplitudes of positive sequence signal 15, negative sequence signal 16 and sideband signal 17 are extracted. The static eccentricity is obtained by the ratio of the amplitude of negative sequence signal 16 to the amplitude of positive sequence signal 15, and the dynamic eccentricity is obtained by the ratio of the amplitude of sideband signal 17 to the amplitude of positive sequence signal 15.

[0020] Specifically, when superimposing two sets of voltage signals after analog-to-digital conversion, a group superposition model is used: ; V D1 The voltage signal output by the first linear Hall sensor 1 is converted into a digital signal by analog-to-digital conversion, V D2 The voltage signal output by the second linear Hall sensor 2 is converted into a digital signal by analog-to-digital conversion, V D3 The voltage signal output by the third linear Hall sensor 3 is converted into a digital signal by analog-to-digital conversion, V D4 The voltage signal output by the fourth linear Hall sensor 4 is converted into a digital signal by analog-to-digital conversion, V D5 The voltage signal output by the fifth linear Hall sensor 5 is converted into a digital signal by analog-to-digital conversion, V D6 The digital signal, U, is the voltage signal output by the sixth linear Hall sensor 6 after analog-to-digital conversion. m1 For a sinusoidal signal V 3α The amplitude of the third harmonic, U m2 For a sinusoidal signal V 3β The amplitude, θ is the actual electrical angle of the rotor, 3θ r For V 3α V 3β The electrical angle difference between them.

[0021] Specifically, when the third harmonic V is obtained through the first set of linear Hall sensors 3α amplitude U m1 Greater than the third harmonic V obtained by the second set of linear Hall sensors 3β amplitude U m2 At that time, the first axial layer is eccentric, and the third harmonic V obtained by the second set of linear Hall sensors... 3β amplitude U m2 Greater than the third harmonic V obtained by the first set of linear Hall sensors 3α amplitude U m1 Then the second axial layer is eccentric.

[0022] Specifically, the first set of linear Hall sensors is located on the circumference of the first radius and is uniformly arranged with an electrical angle of N1 along the circumference; the second set of linear Hall sensors is located on the circumference of the second radius and is uniformly arranged with an electrical angle of N1 along the circumference; the second set of linear Hall sensors is offset from the first set of linear Hall sensors by an electrical angle of N2. Where N1=iP r M / P s ; i is the harmonic order, P s It is the number of slots, P r It is the pole number, and M is the number of teeth between any two slots; If the third harmonic sinusoidal signal V 3α and V 3β If they are orthogonal, then θ r =2kπ±π / 6, k=0,1,2,...; Given the first radius, according to θ r The second radius, θ, is obtained by calculating the piecewise function expression. r The piecewise function expression is: ; in, r2 is the second radius, R1 is the inner diameter of the rotor of the axial skewed pole motor, R3 is the outer diameter of the rotor of the axial skewed pole motor, R2 is the radius of the center of symmetry with the skewed pole permanent magnet 8, k1 is the slope of the skewed pole magnet in the R1-R2 segment, and k2 is the slope of the skewed pole magnet in the R2-R3 segment.

[0023] The first axial layer and the second axial layer are divided based on the rotor inner diameter R1, rotor outer diameter R3, and the radius R2 of the symmetry center with the skewed permanent magnet 8 of the axial skewed pole motor. The first radius and the second radius are located in the R1-R2 segment or the R2-R3 segment, respectively. After determining the first radius for installing the first set of linear Hall sensors, the required electrical angle difference N2 between the first set of linear Hall sensors and the second set of linear Hall sensors is determined according to the required staggered installation. r (equal), thereby determining the second radius for installing the second set of linear Hall sensors.

[0024] Specifically, such as Figure 3 As shown, the complex factor filter is composed of a first detector 12, a second detector 13 and a third detector 14 interconnected. Orthogonal third harmonic sinusoidal signal V 3α and V 3β The outputs of the three detector filters are subtracted to obtain the intermediate signal; The intermediate signal is added to the output signal of the first detector 12 to serve as the input signal of the first detector 12. The first detector 12 receives the quadrature third harmonic sinusoidal signal V. 3α and V 3β Extract the positive-sequence signal 15, which has the same frequency as the motor rotor's rotation. The expression for the positive-sequence signal 15 is: ; The intermediate signal is added to the output signal of the second detector 13 to serve as the input signal of the second detector 13. The second detector 13 receives the quadrature third harmonic sinusoidal signal V.3α and V 3β Extract the negative sequence signal 16, which is opposite to the electric frequency of the motor rotor rotation. The expression for the negative sequence signal 16 is: ; The intermediate signal is added to the output signal of the third detector 14 to form the input signal of the third detector 14. The third detector 14 receives the quadrature third harmonic sinusoidal signal V. 3α and V 3β The sideband signal 17 is extracted from it, and the expression for sideband signal 17 is: ; In the formula, s is the input signal, p is the number of pole pairs of the permanent magnet motor, ω0 is the frequency of the positive sequence signal, and ω c ω is the cutoff frequency. c =k c ×ω0,k c It is a positive number.

[0025] Specifically, the synchronous reference system phase-locked loop includes a first synchronous reference system phase-locked loop and a second synchronous reference system phase-locked loop. The first synchronous reference system phase-locked loop is used to receive the negative sequence signal 16 and extract the amplitude of the negative sequence signal 16 to calculate the static eccentricity. The second synchronous reference system phase-locked loop is used to receive the sideband signal 17 and extract the amplitude of the sideband signal 17 to calculate the dynamic eccentricity.

[0026] The first synchronous reference system phase-locked loop receives the negative sequence signal 16 output by the second detector 13 and extracts its amplitude; the second synchronous reference system phase-locked loop receives the sideband signal 17 output by the third detector 14 and extracts its amplitude; the static eccentricity is output by calculating the ratio of the amplitude of the negative sequence signal 16 to the amplitude of the positive sequence signal 15, and the dynamic eccentricity is output by calculating the ratio of the amplitude of the sideband signal 17 to the amplitude of the positive sequence signal 15.

[0027] Example 2 This embodiment uses a three-phase, 24-slot, 16-pole axial skew-pole flux permanent magnet motor as an example for verification. Figure 4 As shown, the axial skewed flux permanent magnet motor includes a permanent magnet 8 with skewed poles, an annular winding 10, stator teeth 9 and a rotor. The permanent magnet 8 with skewed poles is uniformly mounted on the rotor in the circumferential direction, and the magnetization directions of two adjacent permanent magnets 8 are opposite. A stator slot 7 is formed between any two stator teeth 9, and an annular winding 10 of the same phase is provided in the stator slot 7.

[0028] Under uniform rotation, the magnetization of the permanent magnet 8 results in an air gap magnetic flux density near the stator slot 7 exhibiting a near-sinusoidal waveform distribution. The stator contains 24 slots, each 4mm wide, accommodating linear Hall sensors packaged in DRV5055 packages. The first linear Hall sensor 1, the second linear Hall sensor 2, and the third linear Hall sensor 3 in the first axial layer are installed at equal intervals, separated by one slot, with the three-phase Hall signals differing by 4π / 3 electrical degrees, satisfying N1=iP. r M / P s The fourth linear Hall sensor 4, the fifth linear Hall sensor 5, and the sixth linear Hall sensor 6 in the second axial layer are also installed at equal intervals, separated by one slot, and the three-phase Hall signals differ by 4π / 3 electrical degrees, satisfying N1=iP. r M / P s .

[0029] If the mounting radius r1 of the linear Hall sensor set in the first axial layer is 42mm, in order to ensure that the signals after the two sets of axial layers are superimposed are a set of orthogonal signals, i.e. θ r =2kπ±π / 6, then according to the required misalignment of the first set of linear Hall sensors and the second set of linear Hall sensors, the difference in electrical angle N2 (N2 and θ) r (equal), through θ r The piecewise function expression yields an installation radius r2 of 47.8 mm for the linear Hall sensor installed in the second axial layer.

[0030] like Figure 5-6 As shown, two sets of six asymmetrically mounted linear Hall sensors detect voltage signals D1, D2, D3, D4, D5, and D6, which are converted into digital signals V after analog-to-digital conversion. D1 V D2 V D3 V D4 V D5 V D6 Grouped signals are superimposed, and the third harmonic V is obtained through the first group of linear Hall sensors. 3α amplitude U m1 The third harmonic V is 0.025V, obtained through the second set of linear Hall sensors. 3β amplitude U m2 It is 0.03V, and the amplitude is U. m2 Greater than amplitude U m1 It was determined to be an eccentricity of the second axial layer side.

[0031] like Figure 7-9 As shown, the third harmonic V is filtered by a complex factor filter. 3α V 3βThe positive sequence signal 15, negative sequence signal 16, and sideband signal 17 are extracted. Then, through the first synchronous reference system phase-locked loop and the second synchronous reference system phase-locked loop, the amplitude of the negative sequence signal 16 and the amplitude of the sideband signal 17 are extracted. The ratio of the amplitude of the negative sequence signal 16 to the amplitude of the positive sequence signal 15 is calculated to obtain a static eccentricity of 20%. The ratio of the amplitude of the sideband signal 17 to the amplitude of the positive sequence signal 15 is calculated to obtain a dynamic eccentricity of 6.7%.

[0032] Example 3 like Figure 2 As shown, Embodiment 3 of the present invention provides an axial skewed pole motor eccentricity detection system, comprising: Voltage signal acquisition module: A first set of linear Hall sensors is installed on the first axial layer of the stator slot 7 of the axial skewed pole motor, which includes a first linear Hall sensor 1, a second linear Hall sensor 2 and a third linear Hall sensor 3 located on the circumference of the first radius and equally spaced along the circumference. A second set of linear Hall sensors is installed in the second axial layer of the stator slot 7 of the axial skewed pole motor. The sensor includes a fourth linear Hall sensor 4, a fifth linear Hall sensor 5 and a sixth linear Hall sensor 6, which are located on the circumference of the second radius and are equally spaced along the circumference. The first radius is not equal to the second radius. The magnetic sensing surface of any linear Hall sensor is opposite to the surface of the permanent magnet 8 on the rotor, and the second set of linear Hall sensors is staggered with the first set of linear Hall sensors to form a complementary detection area. Digital Signal Processor Module 11: After performing analog-to-digital conversion on the voltage signals output from two sets of linear Hall sensors, and then superimposing the grouped signals, a pair of orthogonal third harmonic sinusoidal signals V are obtained. 3α and V 3β ; Based on the third harmonic sinusoidal signal V 3α and V 3β The fundamental amplitude determines the direction of eccentricity; Based on a complex factor filter and a synchronous reference frame phase-locked loop, the quadrature third harmonic sinusoidal signal V... 3α and V 3β The amplitudes of positive sequence signal 15, negative sequence signal 16 and sideband signal 17 are extracted. The static eccentricity is obtained by the ratio of the amplitude of negative sequence signal 16 to the amplitude of positive sequence signal 15, and the dynamic eccentricity is obtained by the ratio of the amplitude of sideband signal 17 to the amplitude of positive sequence signal 15.

[0033] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them; although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of the present invention or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the technical solutions claimed in the present invention.

Claims

1. A method for eccentricity detection of an asymmetrically layered Hall-based axial skewed-field motor, applied to a segmented skewed-field motor, characterized in that, Comprising: Step 1, installing a first group of linear Hall sensors on the first axial layer of the axial skewed-field motor stator slot, which includes a first linear Hall sensor, a second linear Hall sensor and a third linear Hall sensor located on the circumference of the first radius and equally spaced along the circumference; Installing a second group of linear Hall sensors on the second axial layer of the axial skewed-field motor stator slot, which includes a fourth linear Hall sensor, a fifth linear Hall sensor and a sixth linear Hall sensor located on the circumference of the second radius and equally spaced along the circumference, wherein the first radius is not equal to the second radius; The magnetic sensitive surface of any linear Hall sensor is opposite to the surface of the permanent magnet on the rotor, and the second group of linear Hall sensors is arranged staggered with the first group of linear Hall sensors to form a complementary detection area; Step 2, after the voltage signals outputted by the two groups of linear Hall sensors are analog-digital converted, the signals are grouped and superposed to obtain a pair of orthogonal third harmonic sinusoidal signals V 3α and V 3β ; Step 3, the direction of eccentricity is determined from the fundamental amplitude of the third harmonic sinusoidal signal V 3α and V 3β ​ Step 4: Extracting positive, negative and sideband sequence signals from the quadrature third harmonic sinusoidal signal V 3α and V 3β The amplitude of the positive, negative and sideband sequence signals are extracted from the quadrature third harmonic sinusoidal signal V The static eccentricity ratio is obtained from the ratio of the amplitude of the negative sequence signal to the amplitude of the positive sequence signal, and the dynamic eccentricity ratio is obtained from the ratio of the amplitude of the sideband sequence signal to the amplitude of the positive sequence signal.

2. The eccentricity detection method of the axial skewed-field motor according to claim 1, characterized in that: When the two groups of voltage signals after analog-to-digital conversion are subjected to grouped signal superposition, a grouped superposition model is adopted: ； V D1 is the digital signal after analog-digital conversion of the voltage signal output by the first linear Hall sensor, V D2 is the digital signal after analog-digital conversion of the voltage signal output by the second linear Hall sensor, V D3 is the digital signal after analog-digital conversion of the voltage signal output by the third linear Hall sensor, V D4 is the digital signal after analog-digital conversion of the voltage signal output by the fourth linear Hall sensor, V D5 is the digital signal after analog-digital conversion of the voltage signal output by the fifth linear Hall sensor, V D6 is the digital signal after analog-digital conversion of the voltage signal output by the sixth linear Hall sensor, U m1 is the amplitude of the sinusoidal signal V 3α is the amplitude of the third harmonic, U m2 is the amplitude of the sinusoidal signal V 3β is the amplitude of the sinusoidal signal V r is the actual electrical angle of the rotor, 3θ 3α is the electrical angle difference between V 3β and V 3. The eccentricity detection method of an axial skewed-field electric machine according to claim 2, characterized in that: when the amplitude U 3α of the third harmonic V m1 obtained by the first set of linear Hall sensors is greater than the amplitude U 3β of the third harmonic V m2 obtained by the second set of linear Hall sensors, the first axial layer is eccentric to the side, and when the amplitude U 3β of the third harmonic V m2 obtained by the second set of linear Hall sensors is greater than the amplitude U 3α of the third harmonic V m1 obtained by the first set of linear Hall sensors, the second axial layer is eccentric to the side.

4. The eccentricity detection method of an axial skewed-field electric machine according to claim 3, characterized in that, Comprising: The first group of linear Hall sensors are located on the circumference of the first radius and are arranged along the circumference at equal N1 electric angles; The second group of linear Hall sensors are located on the circumference of the second radius and are arranged along the circumference at equal N1 electric angles; The second group of linear Hall sensors are staggered with the first group of linear Hall sensors by N2 electric angles; where N1 = iP r M / P s ; i is the harmonic order, P s is the number of slots, P r is the number of poles, M is the number of teeth between any two slots; If the third harmonic sinusoidal signal V 3α and V 3β are orthogonal, θ r = 2kπ ± π / 6, k = 0, 1, 2,... The second radius is calculated from the expression of the piecewise function, θ r The second radius is calculated from the expression of the piecewise function, θ r The expression of the piecewise function is: ； Wherein, r2 is the second radius, R1 is the inner diameter of the rotor of the axial skewed-field motor, R3 is the outer diameter of the rotor of the axial skewed-field motor, R2 is the radius of the center of symmetry with skewed-field permanent magnets, k1 is the slope of the skewed-field magnets in the R1-R2 segment, and k2 is the slope of the skewed-field magnets in the R2-R3 segment.

5. The eccentricity detection method of an axial skewed-field electric machine according to claim 4, characterized in that: The complex factor filter is composed of a first detection filter, a second detection filter and a third detection filter interconnected; orthogonal third harmonic sinusoidal signal V 3α and V 3β subtraction of 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 the input signal of the first detection filter, and the first detection filter extracts a positive sequence signal of the same frequency as the rotation frequency of the motor rotor from the positive third harmonic sinusoidal signal V 3α and V 3β The positive sequence signal of the same frequency as the rotation frequency of the motor rotor is extracted from the positive third harmonic sinusoidal signal V ; 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 second detection filter extracts a negative sequence signal of the third harmonic sinusoidal signal V 3α and V 3β The negative sequence signal is extracted from the motor rotor rotation electric frequency, and the expression of the negative sequence signal is: ; The intermediate signal is added to the output signal of the third detection filter as an input signal of the third detection filter, and the third detection filter extracts a third harmonic signal V 3α and V 3β from the intermediate signal, and the expression of the third harmonic signal is: ; where s is an input signal, p is a pole pair number of the permanent magnet motor, ω0is a frequency of a positive sequence signal, ω c is a cutoff frequency, ω c =k c ×ω0, k c is a positive number.

6. The eccentricity detection method of an axial skewed-field electric machine according to claim 5, characterized in that: The synchronous reference frame phase-locked loop includes a first synchronous reference frame phase-locked loop and a second synchronous reference frame phase-locked loop, the first synchronous reference frame phase-locked loop is used for receiving the negative sequence signal and extracting the amplitude of the negative sequence signal to calculate the static eccentricity rate; The second synchronous reference frame phase-locked loop is used for receiving the sideband signal and extracting the amplitude of the sideband signal to calculate the dynamic eccentricity rate.

7. An eccentricity detection system for an axial flux motor, characterized by Comprising: The voltage signal acquisition module: installing a first group of linear Hall sensors on the first axial layer of the axial skewed-field motor stator slot, which includes a first linear Hall sensor, a second linear Hall sensor and a third linear Hall sensor located on the circumference of the first radius and equally spaced along the circumference; Installing a second group of linear Hall sensors on the second axial layer of the axial skewed-field motor stator slot, which includes a fourth linear Hall sensor, a fifth linear Hall sensor and a sixth linear Hall sensor located on the circumference of the second radius and equally spaced along the circumference, wherein the first radius is not equal to the second radius; The magnetic sensitive surface of any linear Hall sensor is opposite to the surface of the permanent magnet on the rotor, and the second group of linear Hall sensors is arranged staggered with the first group of linear Hall sensors to form a complementary detection area; Digital signal processor module: after the voltage signals outputted by the two sets of linear Hall sensors are converted into digital signals, the signals are grouped and superposed to obtain a pair of orthogonal third harmonic sinusoidal signals V 3α and V 3β ; The direction of eccentricity is determined from the fundamental amplitude of the third harmonic sinusoidal signal V 3α and V 3β . Based on a complex factor filter and a synchronous reference frame phase-locked loop, a positive-sequence signal is extracted from a quadrature third harmonic sinusoidal signal V 3α and V 3β The amplitudes of the positive-sequence signal, the negative-sequence signal and the sideband signal are extracted, the static eccentricity ratio is obtained according to the ratio of the amplitude of the negative-sequence signal to the amplitude of the positive-sequence signal, and the dynamic eccentricity ratio is obtained according to the ratio of the amplitude of the sideband signal to the amplitude of the positive-sequence signal.

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