Method and device for detecting spatial posture of magnetic levitation pump rotor

Abstract

The application discloses a kind of detection method and device for the space posture of magnetic suspension pump rotor.The application is respectively orthogonal in the two planes under the air gap of magnetic suspension pump Four Hall sensors are installed, and the voltage signals in different planes and different directions generated by the movement of rotor are detected by Hall sensor.Difference and arctangent can be obtained by the x, y direction Hall signals collected by the plane closer to the rotor in the radial direction of rotor rotation angle;The x, y direction Hall signals collected by the two planes are respectively processed by a four-sensor second-order differential amplification circuit to obtain the x, y direction Hall voltage signal difference generated by the tilt of rotor, and then the axial displacement generated by the tilt of rotor is obtained, and the tilt angle of rotor around x, y plane is obtained according to geometric relationship.The method and device proposed by the application are simpler in structure, and the data calculation accuracy and efficiency are high.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of magnetic suspension pump rotor detection method in the field of magnetic suspension pump sensing, especially, a kind of magnetic suspension pump rotor space posture detection method and device. BACKGROUND

[0002] Magnetic suspension pump is widely used in the field of semiconductor process, biomedicine processing, etc., since its bearingless, no mechanical friction, continuous and smooth flow without pulsation, therefore in these industries needing ultra-clean working environment has been widely used. However, due to its bearingless structural characteristics, compared with traditional permanent magnet synchronous motor, an additional set of suspension winding is needed to ensure the suspension of rotor. In addition, due to the mutual interference of suspension winding and driving winding, it also makes the magnetic suspension pump rotor in suspension and driving control has certain difficulty. Precise measurement of magnetic suspension pump rotor space posture is the premise of stable control, however, due to the compact structure and limited space of magnetic suspension pump, it is difficult to obtain the whole space posture of the rotor by direct measurement of sensor, especially the tilt angle of the rotor, so a new detection method is needed to measure the space posture of the magnetic suspension pump rotor. SUMMARY

[0003] In order to solve the problems in the background art, the present application provides a method for measuring the space posture of the suspended rotor of the magnetic suspension pump. The present application collects signals through two pairs of orthogonal distributed Hall sensors located in two planes, and carries out double differential amplification, so as to obtain the difference value of the axial magnetic induction intensity signal, and then calculates the tilt angle of the rotor. The signal value of the Hall sensor closer to the rotor plane is differentiated and inverse tangent to obtain the rotation angle of the rotor.

[0004] The technical scheme adopted by the present application is:

[0005] I. A method for detecting the space posture of the rotor of a magnetic suspension pump

[0006] Step 1: install two groups of Hall detection units on the inner side wall of the stator teeth of the magnetic suspension pump, the two groups of Hall detection units are arranged vertically opposite, the planes where the two groups of Hall detection units are parallel and spaced apart; each group of Hall detection units includes four Hall sensors arranged equidistantly along the circumference;

[0007] Step 2: the rotor of the magnetic suspension pump is suspended and immovable, and the two groups of Hall detection units are calibrated;

[0008] Step 3: after calibration, the Hall signals of the rotor during rotation are collected by the two groups of Hall detection units, and the rotation angle of the rotor in XY plane and the tilt angle of the rotor are calculated according to the two groups of Hall detection units, wherein the XY plane is parallel to the plane where each group of Hall detection units is located.

[0009] The step 2 is specifically:

[0010] The rotor of the magnetic suspension pump is suspended, first, the N and S poles of the rotor are turned to the X axis, the Hall voltage signals corresponding to the X axis of the two groups of Hall detection units in this state are obtained and used as the X axis reference Hall voltage, then the N and S poles of the rotor are turned to the Y axis, the Hall voltage signals corresponding to the Y axis of the two groups of Hall detection units in this state are obtained and used as the Y axis reference Hall voltage, and the corresponding Hall sensors are calibrated according to the X axis reference Hall voltage and the Y axis reference Hall voltage.

[0011] The step 3 is specifically:

[0012] After the calibration, the rotation angle of the rotor in the XY plane is calculated according to the Hall voltage signals collected by the group of Hall detection units close to the rotor plane;

[0013] and the tilt angle component of the rotor in the X axis is calculated according to the Hall voltage signals collected by the Hall sensors corresponding to the two groups of Hall detection units on the X axis, the tilt angle component of the rotor in the Y axis is calculated according to the Hall voltage signals collected by the Hall sensors corresponding to the two groups of Hall detection units on the Y axis, and then the tilt angle of the rotor is calculated.

[0014] The Hall voltage signals collected by the group of Hall detection units close to the rotor plane are specifically:

[0015] The Hall voltage signals collected by the group of Hall detection units close to the rotor plane are specifically: XA1 The first X axis Hall voltage U XA2 , the second X axis Hall voltage U YA1 , the first Y axis Hall voltage U YA2 , and the second Y axis Hall voltage U XA1 , and the second X axis Hall voltage U XA2 are differentially calculated to obtain the X axis relative Hall voltage U X , and the first Y axis Hall voltage U YA1 and the second Y axis Hall voltage U YA2 are differentially calculated to obtain the Y axis relative Hall voltage U Y , and the rotation angle of the rotor in the XY plane is calculated by the following formula

[0016]

[0017] The inclination angle component of the rotor in the X-axis is calculated according to the Hall voltage signals collected by the Hall sensors in the X-axis corresponding to the two groups of Hall detection units, the inclination angle component of the rotor in the Y-axis is calculated according to the Hall voltage signals collected by the Hall sensors in the Y-axis corresponding to the two groups of Hall detection units, and then the inclination angle of the rotor is calculated, specifically:

[0018] S1: After differentiating the two X-axis Hall voltages collected by each group of Hall detection units, the corresponding X-axis relative Hall voltage U X is obtained, and then after differentiating the X-axis relative Hall voltages U X corresponding to the two groups of Hall detection units, the X-axis Hall voltage signal difference ΔU X caused by the inclination of the rotor is obtained.

[0019] S2: After differentiating the two Y-axis Hall voltages collected by each group of Hall detection units, the corresponding Y-axis relative Hall voltage U Y is obtained, and then after differentiating the Y-axis relative Hall voltages U Y corresponding to the two groups of Hall detection units, the Y-axis Hall voltage signal difference ΔU Y caused by the inclination of the rotor is obtained.

[0020] S3: According to the X-axis Hall voltage signal difference ΔU X caused by the inclination of the rotor and the Y-axis Hall voltage signal difference ΔU Y caused by the inclination of the rotor, the axial displacement components Δz X and Δz Y in the X and Y directions caused by the inclination are calculated by using the calibrated axial position deviation-voltage relationship in the X-axis and the Y-axis when the rotor is inclined.

[0021] S4: The inclination angle θ of the rotor is calculated by using the following formula:

[0022]

[0023] Wherein, θ X is the inclination angle component of the rotor in the X-axis, θ Y is the inclination angle component in the Y-axis, and d is the diameter of the rotor.

[0024] II. A magnetic suspension pump rotor space posture detection device

[0025] The detection device comprises a Hall detection unit, a reference correction unit, a first differential amplification circuit, a double-stage differential amplification circuit and a signal calculation circuit, two groups of Hall detection units are installed on the inner side wall of the stator teeth of the magnetic suspension pump, the two groups of Hall detection units are arranged in vertical opposition, and the planes where the two groups of Hall detection units are arranged are parallel and spaced apart; each group of Hall detection units comprises four Hall sensors arranged at equal intervals along the circumference.

[0026] The reference correction unit is used for correcting each Hall detection unit according to the reference Hall voltage collected when the rotor of the magnetic suspension pump is suspended and immovable.

[0027] The first differential amplification circuit is used for performing differential operation on the X-axis / Y-axis Hall voltage signals collected by the group of Hall detection units close to the rotor plane and sending the corresponding operation results to the signal calculation circuit.

[0028] The double-stage differential amplification circuit is used for performing twice differential operation on the Hall voltage signals collected by the two groups of Hall detection units and sending the corresponding operation results to the signal calculation circuit.

[0029] The signal calculation circuit is used for calculating the rotation angle of the rotor in the XY plane and the tilt angle of the rotor according to the differential operation results sent by the first differential amplification circuit and the double-stage differential amplification circuit.

[0030] The double-stage differential amplification circuit comprises two first-stage differential amplification circuits and one second-stage differential amplification circuit, the two input ends of each first-stage differential amplification circuit are used as the input ends of the double-stage differential amplification circuit, the output ends of the two first-stage differential amplification circuits are connected with the two input ends of the second-stage differential amplification circuit respectively, and the output end of the second-stage differential amplification circuit is used as the output end of the double-stage differential amplification circuit.

[0031] The present application has the following advantages:

[0032] 1. The Hall sensors are orthogonally arranged in two planes, the collected signals of the Hall sensors on the two sides of the rotor in the same plane and in the same direction are subjected to the front-stage differential amplification circuit, the common-mode signal and the temperature drift can be suppressed, the characteristics of self-compensation and linear correction are achieved, the Hall signals of the rotor of the magnetic suspension pump in the direction can be accurately obtained, the Hall signals in different planes are subjected to differential amplification by the rear-stage differential amplification circuit, the noise can be removed and corrected, the tilt angle of the rotor is calculated, and the state of the rotor during rotation is analyzed and controlled.

[0033] 2. The Hall signals in the plane close to the rotor are subjected to differential processing based on the same detection device, and the rotation angle of the rotor in the XY plane can be obtained through the inverse tangent function.

[0034] 3. This invention can simultaneously measure the rotation angle around the Z-axis and the tilt angle relative to the XY plane using a set of detection devices, thus completing the measurement of the spatial attitude of the magnetic levitation pump rotor. The Hall sensor used is small in size, easy to install, and has a simple and compact overall structure. Attached Figure Description

[0035] Figure 1 A cross-sectional view showing the placement of the Hall sensor on the magnetic levitation pump.

[0036] Figure 2 A top view showing the location of the Hall sensor on the magnetic levitation pump.

[0037] Figure 3 This is a second-order differential amplifier circuit for signal processing.

[0038] Figure 4 This is a schematic diagram of the geometric relationship when the rotor is tilted.

[0039] Figure 5 This is a flowchart of the method of the present invention.

[0040] In the diagram: 1. Rotor, 2. Stator, 3. Hall sensor, 4. Floating winding, 5. Drive winding. Detailed Implementation

[0041] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The following is a specific implementation process.

[0042] like Figure 5 As shown, this invention proposes a method for detecting the spatial attitude of a magnetic levitation pump rotor, specifically including the following steps:

[0043] Step 1: Install two sets of Hall effect sensors on the inner wall of the stator teeth of the magnetic levitation pump. The two sets of Hall effect sensors are arranged vertically opposite each other, with parallel and spaced planes between them. These two planes are denoted as A and B, respectively. Each Hall sensor in plane A is directly below a Hall sensor in plane B. The line connecting the two Hall sensors is parallel to the Z-axis. Each set of Hall effect sensors includes four Hall sensors 3 arranged at equal intervals along the circumference, forming two pairs of orthogonally arranged Hall sensors. The two sets of Hall effect sensors contain a total of eight Hall sensors, all with identical structure and model.

[0044] Step 2: With the rotor of the magnetic levitation pump suspended and stationary, perform benchmark calibration on the two sets of Hall effect detection units;

[0045] Step 2 is as follows:

[0046] The rotor of the magnetic suspension pump is suspended and immovable, first, the N pole and the S pole of the permanent magnet rotor are turned to the X axis, the Hall voltage signals corresponding to the X axis of the two groups of Hall detection units in this state are obtained and used as the X axis reference Hall voltage, then the N pole and the S pole of the permanent magnet rotor are turned to the Y axis, the Hall voltage signals corresponding to the Y axis of the two groups of Hall detection units in this state are obtained and used as the Y axis reference Hall voltage, the corresponding Hall sensors are calibrated according to the X axis reference Hall voltage and the Y axis reference Hall voltage, that is, the constant coefficient k after calibration is obtained c .

[0047] Step 3: After the correction is completed, the Hall signals of the rotor rotation are collected by the two groups of Hall detection units, and the rotation angle of the rotor in the XY plane and the tilt angle of the rotor are calculated according to the two groups of Hall detection units, wherein the XY plane is a plane parallel to the plane where each group of Hall detection units is located.

[0048] Step 3 is specifically:

[0049] After the correction is completed, the rotation angle of the rotor in the XY plane is calculated according to the Hall voltage signals collected by the group of Hall detection units close to the rotor plane;

[0050] and the tilt angle component of the rotor generated on the X axis is calculated according to the Hall voltage signals collected by the Hall sensors corresponding to the two groups of Hall detection units on the X axis, the tilt angle component of the rotor generated on the Y axis is calculated according to the Hall voltage signals collected by the Hall sensors corresponding to the two groups of Hall detection units on the Y axis, and then the tilt angle of the rotor is calculated.

[0051] The rotation angle of the rotor in the XY plane is calculated according to the Hall voltage signals collected by the group of Hall detection units close to the rotor plane, which is specifically:

[0052] The Hall voltage signals collected by the group of Hall detection units close to the rotor plane are the first X axis Hall voltage U XA1 and the second X axis Hall voltage U XA2 , the first Y axis Hall voltage U YA1 and the second Y axis Hall voltage U YA2 , the first X axis Hall voltage U XA1 and the second X axis Hall voltage U XA2 are calculated by difference, and the X axis relative Hall voltage U X is obtained, the first Y axis Hall voltage U YA1 and the second Y axis Hall voltage U YA2 are calculated by difference, and the Y axis relative Hall voltage U Y is obtained, and the rotation angle of the rotor in the XY plane is calculated by the following formula

[0053]

[0054] The tilt angle component of the rotor in the X-axis is calculated according to the Hall voltage signals collected by the Hall sensors in the X-axis corresponding to the two groups of Hall detection units, the tilt angle component of the rotor in the Y-axis is calculated according to the Hall voltage signals collected by the Hall sensors in the Y-axis corresponding to the two groups of Hall detection units, and then the tilt angle of the rotor is calculated, specifically:

[0055] S1: Collect the Hall signals of the eight Hall sensors, denoted as U XA1 , U XA2 , U YA1 , U YA2 , U XB1 , U XB2 , U YB1 , U YB2 The two X-axis Hall voltages collected by each group of Hall detection units are respectively calculated by difference, and the corresponding X-axis relative Hall voltage U X is obtained. X The X-axis relative Hall voltages U X corresponding to the two groups of Hall detection units are calculated by difference, and the X-axis Hall voltage signal difference ΔU Y caused by the tilt of the rotor is obtained.

[0056] S2: The two Y-axis Hall voltages collected by each group of Hall detection units are respectively calculated by difference, and the corresponding Y-axis relative Hall voltage U Y is obtained. Y The Y-axis relative Hall voltages U X corresponding to the two groups of Hall detection units are calculated by difference, and the Y-axis Hall voltage signal difference ΔU c caused by the tilt of the rotor is obtained.

[0057] According to the characteristics of the signals collected by the relative arrangement of the Hall sensors, the actual X and Y direction voltage signals U XA1 of the rotor on the A plane are XA2 , U Y = k c |U YA1 -U YA2 |, where k c is a constant coefficient after calibration.

[0058] S3: According to the X-axis Hall voltage signal difference ΔU X caused by the tilt of the rotor and the Y-axis Hall voltage signal difference ΔU Y, the axial position at the time of the calibrated rotor tilt is used to calculate the axial displacement component Δz in the X and Y directions due to the tilt using the X-axis deviation-voltage relationship and the Y-axis deviation-voltage relationship X , Δz Y ; wherein the axial position at the time of the calibrated rotor tilt is linear in the X-axis deviation-voltage relationship and the Y-axis deviation-voltage relationship, and satisfies the following relationship:

[0059] Δz X = k x ΔU X + b

[0060] Δz Y = k y ΔU Y + b

[0061] wherein k x and k y are the X-axis fitting slope and the Y-axis fitting slope, respectively, and b is the fitting intercept.

[0062] Therefore, the calibration of the above linear relationship can be completed through linear fitting.

[0063] S4: As shown in the following formula, the tilt angle θ of the rotor is calculated: Figure 4

[0064]

[0065] wherein θ X is the tilt angle component of the rotor in the X-axis, θ Y is the tilt angle component in the Y-axis, and d is the rotor diameter.

[0066] The application also proposes a detection device for the spatial posture of a magnetic suspension pump rotor, and a double-stage differential amplification circuit is designed. The entire detection device includes a Hall detection unit, a reference correction unit, a first differential amplification circuit, a double-stage differential amplification circuit, and a signal calculation circuit. As shown in Figure 1 and Figure 2 , the magnetic suspension pump includes a rotor 1, a stator 2, a suspension winding 4, and a driving winding 5. Two groups of Hall detection units are installed on the inner side wall of the magnetic suspension pump stator teeth, and the two groups of Hall detection units are arranged vertically opposite to each other, and the planes where the two groups of Hall detection units are arranged are parallel and spaced apart, and the two planes are respectively marked as A and B. Each group of Hall detection units includes four Hall sensors 3 arranged at equal intervals along the circumference, and the four Hall sensors form two pairs of orthogonally arranged Hall sensors. The two groups of Hall detection units have a total of 8 Hall sensors, and the Hall sensors are of the same structure type;

[0067] ​A reference correction unit is configured to correct each Hall detection unit according to a reference Hall voltage collected when the rotor 1 of the magnetic suspension pump is suspended and unmoved.

[0068] A first differential amplification circuit is configured to perform differential operation on X-axis / Y-axis Hall voltage signals collected by a group of Hall detection units close to the rotor plane and send corresponding operation results to a signal calculation circuit.

[0069] A double-stage differential amplification circuit is configured to perform twice differential operation on Hall voltage signals collected by two groups of Hall detection units and send corresponding operation results to the signal calculation circuit.

[0070] The signal calculation circuit is configured to calculate a rotation angle of the rotor in the XY plane and a tilt angle of the rotor according to differential operation results sent by the first differential amplification circuit and the double-stage differential amplification circuit.

[0071] As shown in Figure 3 , the designed double-stage differential amplification circuit includes two first-stage differential amplification circuits and one second-stage differential amplification circuit, two input ends of each first-stage differential amplification circuit are input ends of the double-stage differential amplification circuit, output ends of the two first-stage differential amplification circuits are connected to two input ends of the second-stage differential amplification circuit respectively, and an output end of the second-stage differential amplification circuit is an output end of the double-stage differential amplification circuit.

[0072] The two first-stage differential amplification circuits have the same resistance value, according to the characteristics of the differential amplification circuit, the resistance value satisfies Let the signal at the interface 1 of the operational amplifier be V1, the signal at the interface 2 be V2, and the signal at the interface 3 be V3, and the output signal of the amplifier is The amplification multiple is The second-stage differential amplification circuit has a similar structure, in order to reduce the influence of resistance precision and improve the common-mode rejection ratio, the amplification multiple R'2 / R'1 is set to 10 to improve the gain. Through the first-stage differential amplification circuit, the X and Y direction Hall voltage signals U AX , U AY , U BX , U BY on the A plane and the B plane can be obtained respectively. AX U BX and U AY and U BY are sent to the second-stage differential amplification circuit respectively, through amplification on the differential mode signal, the X-axis and Y-axis variable voltage signals U X ' X , U Y ' caused by the tilt of the rotor are obtained.

[0073] Finally, it should be noted that the above examples and descriptions are only used to illustrate the technical solutions of the present application and not to limit the present application. Those skilled in the art should understand that the technical solutions of the present application can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions disclosed by the present application, and all should be covered in the protection scope of the claims of the present application.

Claims

1. A method of detecting the spatial attitude of a magnetic levitation pump rotor, characterized in that The method comprises the following steps: Step 1: two groups of Hall detection units are installed on the inner side wall of the magnetic suspension pump stator tooth, the two groups of Hall detection units are arranged vertically, and the planes where the two groups of Hall detection units are arranged are parallel and spaced apart; each group of Hall detection units comprises four Hall sensors arranged at equal intervals along the circumference; Step 2: the rotor of the magnetic suspension pump is suspended and immobile, and the two groups of Hall detection units are calibrated; Step 3: after calibration, the Hall signals collected by the two groups of Hall detection units when the rotor rotates are used to calculate the rotation angle of the rotor in the XY plane and the tilt angle of the rotor, wherein the XY plane is parallel to the plane where each group of Hall detection units is located; The tilt angle of the rotor calculated according to the two groups of Hall detection units comprises: The tilt angle component of the rotor in the X-axis direction is calculated according to the Hall voltage signals collected by the Hall sensors corresponding to the two groups of Hall detection units in the X-axis direction, the tilt angle component of the rotor in the Y-axis direction is calculated according to the Hall voltage signals collected by the Hall sensors corresponding to the two groups of Hall detection units in the Y-axis direction, and then the tilt angle of the rotor is calculated; specifically: S1: respectively, two X-axis Hall voltages collected by each group of Hall detection units are differentially calculated to obtain corresponding X-axis relative Hall voltages , and the X-axis relative Hall voltages corresponding to the two groups of Hall detection units are differentially calculated to obtain the X-axis Hall voltage signal difference value generated by the rotor tilt ;​ S2: respectively, two Y-axis Hall voltages collected by each group of Hall detection units are differentially calculated to obtain corresponding Y-axis relative Hall voltages , and the Y-axis relative Hall voltages corresponding to the two groups of Hall detection units are differentially calculated to obtain the Y-axis Hall voltage signal difference value generated by the rotor tilt ;​ S3: difference of X-axis Hall voltage signals due to rotor tilt and difference of Y-axis Hall voltage signals due to rotor tilt , and the axial displacement components in X and Y directions due to tilt are calculated using the calibrated X-axis deviation-voltage relationship and Y-axis deviation-voltage relationship at the axial position when the rotor is tilted 、 ; S4: Calculate the tilt angle of the rotor using the following formula : wherein, the tilt angle component generated by the rotor in the X-axis, is the tilt angle component generated in the Y-axis, is the rotor diameter.

2. The method of claim 1, wherein, The step 2 is specifically: The rotor of the magnetic suspension pump is suspended and immobile, the N and S poles of the rotor are first turned to the X-axis, the Hall voltage signals corresponding to the X-axis of the two groups of Hall detection units in this state are obtained and used as the X-axis reference Hall voltage, then the N and S poles of the rotor are turned to the Y-axis, the Hall voltage signals corresponding to the Y-axis of the two groups of Hall detection units in this state are obtained and used as the Y-axis reference Hall voltage, and the corresponding Hall sensors are calibrated according to the X-axis reference Hall voltage and the Y-axis reference Hall voltage.

3. The method of claim 1, wherein, In the step 3, the rotation angle of the rotor in the XY plane is calculated according to the Hall voltage signals collected by the group of Hall detection units close to the rotor plane.

4. The method of claim 3, wherein the magnetic field is generated by a magnet. The rotation angle of the rotor in the XY plane is calculated according to the Hall voltage signals collected by the group of Hall detection units close to the rotor plane, specifically: The Hall voltage signals collected by the set of Hall detection units close to the rotor plane are respectively the first X-axis Hall voltage and the second X-axis Hall voltage , the first Y-axis Hall voltage and the second Y-axis Hall voltage , the first X-axis Hall voltage and the second X-axis Hall voltage are subjected to differential calculation to obtain the X-axis relative Hall voltage , the first Y-axis Hall voltage and the second Y-axis Hall voltage are subjected to differential calculation to obtain the Y-axis relative Hall voltage , and the rotation angle of the rotor in the XY plane is calculated by the following formula : 。 5. A detection device for implementing the method of claim 1-4 for detecting the spatial orientation of a magnetic levitation pump rotor, characterized in that The method comprises a Hall detection unit, a reference calibration unit, a first differential amplification circuit, a double-stage differential amplification circuit and a signal calculation circuit, two groups of Hall detection units are installed on the inner side wall of the magnetic suspension pump stator tooth, the two groups of Hall detection units are arranged vertically, and the planes where the two groups of Hall detection units are arranged are parallel and spaced apart; each group of Hall detection units comprises four Hall sensors arranged at equal intervals along the circumference; The reference calibration unit is used to calibrate each Hall detection unit according to the reference Hall voltage collected when the rotor of the magnetic suspension pump is suspended and immobile; The first differential amplification circuit is used to perform differential operation on the X-axis / Y-axis Hall voltage signals collected by the group of Hall detection units close to the rotor plane and send the corresponding operation results to the signal calculation circuit; The double-stage differential amplification circuit is used to perform differential operation twice on the Hall voltage signals collected by the two groups of Hall detection units and send the corresponding operation results to the signal calculation circuit; The signal calculation circuit is used to calculate the rotation angle of the rotor in the XY plane and the tilt angle of the rotor according to the differential operation results sent by the first differential amplification circuit and the double-stage differential amplification circuit.

6. The detection device of a magnetic levitation pump rotor space posture detection method according to claim 5, characterized in that, The double-stage differential amplification circuit comprises two first-stage differential amplification circuits and a second-stage differential amplification circuit, two input ends of each first-stage differential amplification circuit are input ends of the double-stage differential amplification circuit, output ends of the two first-stage differential amplification circuits are connected with two input ends of the second-stage differential amplification circuit respectively, and an output end of the second-stage differential amplification circuit is an output end of the double-stage differential amplification circuit.

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