Magnetic suspension motor electric eddy current displacement sensor based on external hardware pre-frequency-division interface
By introducing an external hardware prescaler interface circuit, the eddy current displacement sensor interface is easily vulnerable to noise interference and compatibility, and the stability and resolution of the rotor displacement control system of the magnetic levitation motor are improved, meeting the needs of real-time applications.
Patent Information
- Application Number
- CN202521551302.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-24
- Publication Date
- 2025-08-29
- Estimated Expiration
- 2035-07-24
AI Technical Summary
The existing eddy current displacement sensor interface is susceptible to noise interference, difficult to compatible with modern data acquisition systems, and difficult to adapt to dynamic measurement environments, affecting the stability of the rotor displacement control system of the magnetic levitation motor.
The magnetic levitation motor electric eddy current displacement sensor based on the external hardware prescaler interface is adopted, including sensor probes, presets and external hardware prescaler interface circuits. The high-frequency output of the eddy current displacement sensor is reduced through the external hardware prescaler interface circuit, reduce noise interference, and adapt the signal frequency to meet the needs of the magnetic levitation motor rotor displacement control system.
It reduces the sensitivity of the rotor displacement control system of the magnetic levitation motor to noise, improves the system resolution, reduces the burden of sampling data processing, and meets different needs in real-time applications.
Smart Images
Figure CN223285709U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of magnetic levitation motors, in particular to an eddy current displacement sensor for a magnetic levitation motor based on an external hardware pre-frequency division interface. Background Art
[0002] With the development of science and technology and the demands of production, magnetic levitation motors have become a hot topic of research in the international electrical engineering field. A magnetic levitation motor is a type of rotary drive that utilizes magnetic field forces to levitate the rotor, eliminating any mechanical contact between the rotor and stator. It offers significant advantages such as zero friction, zero wear, minimal maintenance, high speed, and high efficiency.
[0003] Magnetic levitation motors are currently widely used in industrial fields such as high-speed centrifugal blowers, micro gas turbines, high-speed centrifugal compressors, vacuum pumps, organic Rankine cycle power generation, high-speed machining centers, and flywheel energy storage. Their application areas are still expanding. The market demand for magnetic levitation high-speed motors has also experienced explosive growth.
[0004] Because the rotor displacement control system of a magnetic levitation motor is unstable under open-loop control, displacement feedback control is required to achieve stable levitation. As a core component of the magnetic levitation motor system, the displacement sensor is responsible for collecting and providing feedback on the rotor's radial and axial displacement deviations, making it a key component in ensuring the proper and stable operation of the magnetic levitation motor. Therefore, the performance of the displacement sensor has a significant impact on the stability of the magnetic levitation motor's rotor displacement control system.
[0005] Non-contact displacement sensors offer significant advantages over contact sensors in many applications due to their ability to measure position without physical contact. This eliminates concerns about wear, friction, and potential damage, ensuring accurate measurement while preserving the integrity of the object being measured. Therefore, non-contact displacement sensors such as optical / laser, capacitive, eddy current, inductive, and vision sensors are becoming the preferred choice.
[0006] Eddy-current displacement sensors are known for their non-contact nature, high resolution, and suitability for real-time control. They utilize the principles of electromagnetic induction to detect subtle changes in the position of a conductive target. The interface between the sensor and external instrumentation is a key factor affecting signal conditioning, noise reduction, compatibility with modern data acquisition systems, and adaptability to dynamic measurement environments.
[0007] The output signal of the eddy current displacement sensor needs to be fed into a controller for calculation to implement the control and vibration suppression algorithms. However, the input voltage range of the controller processor is fixed. Furthermore, because sensor performance is affected by individual differences, installation errors, and electronic component accuracy, the actual measurement performance of the eddy current sensor may differ from the theoretical calculation. Therefore, it is necessary to design an interface module for the eddy current displacement sensor. This interface module should be able to convert the output voltage signal of the eddy current displacement sensor to a range acceptable to the controller processor and possess certain signal conditioning capabilities.
[0008] The interface between eddy-current displacement sensors and external instruments is crucial for their effectiveness in real-world applications. Existing interface methods are susceptible to noise, lack compatibility with modern data acquisition systems, and struggle to adapt to dynamic measurement environments. Therefore, the reliable design of eddy-current displacement sensor interfaces is a pressing technical challenge. Utility Model Content
[0009] The technical problem to be solved by the utility model is to address the deficiencies of the above-mentioned prior art and provide a magnetic levitation motor eddy current displacement sensor based on an external hardware pre-scaling interface to solve the defects of the current eddy current displacement sensor interface.
[0010] In order to solve the above technical problems, the technical solution adopted by the utility model is: a magnetic levitation motor eddy current displacement sensor based on an external hardware pre-scaling interface, including a sensor probe, a preamplifier and an external hardware pre-scaling interface circuit;
[0011] One end of the sensor probe is opposite to the conductor to be measured, and the other end of the sensor probe is connected to the input end of the preamplifier; the output end of the preamplifier is connected to the input end of the external hardware pre-scaling interface circuit; the output end of the external hardware pre-scaling interface circuit is connected to the input end of the magnetic levitation motor rotor displacement control system.
[0012] Furthermore, the sensor probe includes an eddy current coil, a printed circuit board, a coaxial cable and an adapter; the eddy current coil is connected to the printed circuit board through a wire, the printed circuit board and the coaxial cable are electrically connected to the adapter, and the adapter is electrically connected to the preamplifier.
[0013] Furthermore, the sensor probe further includes a probe housing, and the eddy current coil and printed circuit board are both arranged inside the probe housing.
[0014] Furthermore, the outer surface of the probe housing is provided with a position adjustment thread, and the clamping nut is rotated into the probe housing through the position adjustment thread.
[0015] Furthermore, the sensor probe further includes a cable armor wrapped around the outside of the coaxial cable.
[0016] Furthermore, the preamplifier includes an oscillation circuit, a detection circuit and a conditioning circuit electrically connected in sequence; the input end of the oscillation circuit is electrically connected to the adapter in the sensor probe, and the output end is connected to the input end of the detection circuit; the output end of the detection circuit is connected to the input end of the conditioning circuit; the output end of the conditioning circuit is electrically connected to the external hardware pre-division interface circuit.
[0017] Furthermore, the external hardware pre-scaling interface circuit includes a twenty-first resistor R9, a twenty-second resistor R10, a twenty-third resistor R11, a twenty-fourth resistor R12, a twenty-fifth resistor R13, a first counter chip U4, a first dual-input port element IN, and a first five-output port element OUT;
[0018] Among them, the first dual-input port element IN receives the output signal of the conditioning circuit of the preamplifier; one end of the twenty-first resistor is connected to the first dual-input port element IN, and the other end is connected to the first counter chip U4; one end of the twenty-second resistor R10 is connected to the first counter chip U4, and the other end is connected to the first-five output port element OUT; one end of the twenty-third resistor R11 is connected to the first counter chip U4, and the other end is connected to the first-five output port element OUT; one end of the twenty-fourth resistor R12 is connected to the first counter chip U4, and the other end is connected to the first-five output port element OUT; one end of the twenty-fifth resistor R13 is connected to the first counter chip U4, and the other end is connected to the first-five output port element OUT; the first dual-input port element IN and the first-five output port element OUT both have one port connected to the signal ground.
[0019] The beneficial effect of the above-described technical solution is that the magnetic levitation motor eddy current displacement sensor based on an external hardware pre-scaling interface provided by the present utility model can reduce the high-frequency output of the eddy current displacement sensor through the external hardware pre-scaling interface circuit. This significantly reduces the high-frequency noise interference experienced by the signal after frequency reduction by the external hardware pre-scaling interface circuit during subsequent transmission and processing, making the magnetic levitation motor rotor displacement control system less sensitive to noise and weakening the impact of noise on the magnetic levitation motor rotor displacement control system.
[0020] The external hardware pre-scaling interface circuit improves the resolution of the magnetic levitation motor rotor displacement control system under the same external conditions. This means that even with a moderately reduced sampling rate, good signal resolution can still be achieved, meeting application requirements while reducing the sampled data processing and computational burden.
[0021] By introducing an external hardware pre-scaling interface circuit, the static and dynamic performances of the magnetic levitation motor rotor displacement control system can be better balanced to meet different requirements in real-time applications. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Figure 1 This is a structural block diagram of the magnetic levitation motor eddy current displacement sensor based on the external hardware pre-scaling interface provided by the utility model;
[0023] Figure 2 This is a schematic diagram of the sensor probe structure provided by the utility model;
[0024] Figure 3 This is a schematic diagram of the structure of the oscillation circuit in the preamplifier provided by the utility model;
[0025] Figure 4 This is a schematic diagram of the structure of the detection circuit in the preamplifier provided by the utility model;
[0026] Figure 5 This is a schematic diagram of the structure of the conditioning circuit in the preamplifier provided by the utility model;
[0027] Figure 6 This is a schematic diagram of the structure of the external hardware pre-scaling interface circuit provided by the utility model;
[0028] Figure 7 This is a schematic diagram of the process of the external hardware pre-scaling interface circuit signal provided by the utility model entering the DSP for processing.
[0029] In the figure: 1. Eddy current coil; 2. Probe housing; 3. Printed circuit board; 4. Clamping nut; 5. Position adjustment thread; 6. Cable armor; 7. Coaxial cable; 8. Adapter. DETAILED DESCRIPTION
[0030] The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the present invention.
[0031] In this embodiment, the magnetic suspension motor eddy current displacement sensor based on the external hardware pre-scaling interface, such as Figure 1 As shown, it includes a sensor probe, a preamplifier, and an external hardware pre-scaling interface circuit; one end of the sensor probe is opposite to the conductor to be measured (i.e., the magnetic levitation motor rotor), the other end of the sensor probe is connected to the preamplifier, and the other end of the preamplifier is electrically connected to the external hardware pre-scaling interface circuit; the output end of the external hardware pre-scaling interface circuit is electrically connected to the digital signal processor used in the magnetic levitation rotor displacement control system.
[0032] The sensor probe is as Figure 2As shown, it includes a probe housing 2, an eddy current coil 1, a printed circuit board 3, a clamping nut 4, a cable armor 6, a coaxial cable 7 and an adapter 8;
[0033] The eddy current coil 1 and printed circuit board 3 are both arranged inside the probe housing 2, the eddy current coil 1 and the printed circuit board 3 are connected by a wire, and the printed circuit board 3 is electrically connected to the coaxial cable 7; the outer surface of the probe housing 2 is provided with a position adjustment thread 5, and the clamping nut 4 is rotated into the probe housing 2 through the position adjustment thread 5, and the position of the clamping nut 4 can be adjusted as needed; the end of the probe housing 2 is connected to the adapter 8 by the coaxial cable 7, and the adapter 8 is electrically connected to the preamplifier; the outside of the coaxial cable 7 is wrapped with a cable armor 6, which plays a role in physical protection and shielding electromagnetic interference.
[0034] The eddy current signal generated by the eddy current coil 1 is transmitted to the printed circuit board 3 through a wire, then transmitted to the coaxial cable 7 through an electrical connection, and further transmitted to the preamplifier through the adapter 8 for processing.
[0035] The preamplifier includes an oscillation circuit, a detection circuit and a conditioning circuit electrically connected in sequence; the input end of the oscillation circuit is electrically connected to the adapter 8 in the sensor probe, and the output end is connected to the input end of the detection circuit; the output end of the detection circuit is connected to the input end of the conditioning circuit; the output end of the conditioning circuit is electrically connected to the external hardware pre-division interface circuit.
[0036] The oscillator circuit in the preamplifier generates a high-frequency AC signal at a specific frequency, providing an excitation source for the sensor probe, which then generates an alternating magnetic field. The detection circuit monitors the eddy currents generated between the sensor probe's alternating magnetic field and the rotor, converting the resulting changes in electrical parameters into a measurable voltage signal. The signal conditioning circuit improves the signal-to-noise ratio and stability of the voltage signal output by the detection circuit by amplifying the electrical signal, filtering out noise interference, and performing level conversion.
[0037] like Figure 3 As shown, the oscillation circuit includes a first resistor Ra1, a second resistor Ra2, a third resistor Ra3, a fourth resistor Ra4, a fifth resistor Ra5, a first capacitor Ca1, a second capacitor Ca2, a third capacitor Ca3, a first inductor Ls1, a second inductor Ls2, a first transistor Q1 and a first operational amplifier chip U1A;
[0038] Among them, pin 1 of the first resistor Ra1 is connected to signal ground, and pin 2 of the first resistor Ra1 is connected to pin 3 of the first operational amplifier chip U1A; pin 1 of the second resistor Ra2 is connected to the voltage signal VCC, and pin 2 of the second resistor Ra2 is connected to pin 3 of the first operational amplifier chip U1A; pin 1 of the third resistor Ra3 is connected to pin 1 of the first operational amplifier chip U1A, and pin 2 of the third resistor Ra3 is connected to pin 3 of the first transistor Q1; pin 1 of the fourth resistor Ra4 is connected to pin 1 of the first transistor Q1, and pin 2 of the fourth resistor Ra4 is connected to pin 1 of the second inductor Ls2; pin 1 of the fifth resistor Ra5 is connected to pin 2 of the second inductor Ls2, and pin 2 of the fifth resistor Ra5 is connected to signal ground. Pin 2 of the first operational amplifier chip U1A is connected to pin 1 of the first transistor Q1, pin 4 of the first operational amplifier chip U1A is connected to signal ground, and pin 8 of the first operational amplifier chip U1A is connected to voltage signal VDD. Pin 1 of the first inductor Ls1 is connected to the voltage signal VCC, and pin 2 of the first inductor Ls1 is connected to pin 2 of the first operational amplifier chip U1A. Pin 1 of the first capacitor Ca1 is connected to the voltage signal VCC, and pin 2 of the first capacitor Ca1 is connected to pin 2 of the third resistor Ra3. Pin 1 of the second capacitor Ca2 is connected to pin 2 of the first transistor Q1, and pin 2 of the second capacitor Ca2 is connected to pin 1 of the second inductor Ls2. Pin 1 of the third capacitor Ca3 is connected to the voltage signal VCC, and pin 2 of the third capacitor Ca3 is connected to pin 1 of the second inductor Ls2.
[0039] like Figure 4 As shown, the detection circuit includes a sixth resistor Ra6, a seventh resistor Ra7, an eighth resistor Ra8, a ninth resistor Ra9, a tenth resistor Ra10, an eleventh resistor Ra11, a twelfth resistor Ra12, a fourth capacitor Ca4, a fifth capacitor Ca5, a first diode Da1, a second diode Da2, a third diode Da3, and a second operational amplifier chip U1B;
[0040] Among them, pin 1 of the sixth resistor Ra6 is connected to pin 2 of the first diode Da1, and pin 2 of the sixth resistor Ra6 is connected to pin 3 of the second operational amplifier chip U1B; pin 1 of the seventh resistor Ra7 is connected to pin 3 of the second operational amplifier chip U1B, and pin 2 of the seventh resistor Ra7 is connected to pin 1 of the second diode Da2; pin 1 of the eighth resistor Ra8 is connected to the voltage signal VCC, and pin 2 of the eighth resistor Ra8 is connected to pin 2 of the tenth resistor Ra10; pin 1 of the ninth resistor Ra9 is connected to pin 2 of the eighth resistor Ra8, and pin 2 of the ninth resistor Ra9 is connected to signal ground; pin 1 of the tenth resistor Ra10 is connected to pin 2 of the second operational amplifier chip U1B, and pin 2 of the tenth resistor Ra10 is connected to pin 2 of the eighth resistor Ra8; pin 1 of the eleventh resistor Ra11 is connected to pin 2 of the second operational amplifier chip U1B, and pin 2 of the eleventh resistor Ra11 is connected to pin 2 of the second operational amplifier chip U 1B; pin 1 of the twelfth resistor Ra12 is connected to the signal ground, and pin 2 of the twelfth resistor Ra12 is connected to pin 1 of the second operational amplifier chip U1B; pin 1 of the fourth capacitor Ca4 is connected to the voltage signal VCC, and pin 2 of the fourth capacitor Ca4 is connected to pin 1 of the sixth resistor Ra6; pin 1 of the fifth capacitor Ca5 is connected to pin 2 of the second operational amplifier chip U1B, and pin 2 of the fourth capacitor Ca5 is connected to pin 1 of the second operational amplifier chip U1B; pin 1 of the first diode Da1 is connected to pin 2 of the first transistor Q1 in the oscillation circuit, and pin 2 of the first diode Da1 is connected to pin 1 of the sixth resistor Ra6; pin 1 of the second diode Da2 is connected to pin 2 of the seventh resistor Ra7, and pin 2 of the second diode Da2 is connected to the signal ground; pin 1 of the third diode Da3 is connected to pin 1 of the second operational amplifier chip U1B, and pin 2 of the third diode Da3 is connected to the voltage signal VCC.
[0041] like Figure 5 As shown, the conditioning circuit includes a first adjustable DC voltage source V1, a thirteenth resistor R1, a fourteenth resistor R2, a fifteenth resistor R3, a sixteenth resistor R4, a seventeenth resistor R5, an eighteenth resistor R6, a nineteenth resistor R7, a twentieth resistor R8, a sixth capacitor C1, a seventh capacitor C2, a fourth diode D1A, a fifth diode D1B, a third operational amplifier chip U2A, a fourth operational amplifier chip U2B, a fifth operational amplifier chip U2C and a sixth operational amplifier chip U2D;
[0042] Among them, pin 1 of the thirteenth resistor R1 is connected to pin 1 of the first adjustable DC voltage source V1, and pin 2 of the thirteenth resistor R1 is connected to pin 2 of the fourth operational amplifier chip U2B; pin 1 of the fourteenth resistor potentiometer R2 is connected to pin 3 of the third operational amplifier chip U2A, pin 2 of the fourteenth resistor R2 is connected to the positive voltage signal VDC1, and pin 3 of the fourteenth resistor R2 is connected to the negative voltage signal VDC2; pin 1 of the fifteenth resistor R3 is connected to pin 1 of the third operational amplifier chip U2A, and pin 2 of the fifteenth resistor R3 is connected to pin 2 of the fourth operational amplifier chip U2B; pin 1 of the sixteenth resistor R4 is connected to the signal ground, and pin 2 of the sixteenth resistor R4 is connected to the fourth operational amplifier chip Pin 1 of the seventeenth resistor R5 is connected to pin 1 of the fourth operational amplifier chip U2B, and pin 2 of the seventeenth resistor R5 is connected to pin 1 of the nineteenth resistor R7. Pin 1 of the eighteenth resistor (sliding rheostat) R6 is connected to pin 1 of the fourth operational amplifier chip U2B, and pin 2 of the eighteenth resistor R6 is connected to pin 2 of the fourth operational amplifier chip U2B. Pin 1 of the nineteenth resistor R7 is connected to pin 2 of the seventeenth resistor R5, and pin 2 of the nineteenth resistor R7 is connected to pin 3 of the fifth operational amplifier chip U2C. Pin 1 of the twentieth resistor R8 is connected to pin 1 of the fifth operational amplifier chip U2C, and pin 2 of the twentieth resistor R8 is connected to pin 3 of the sixth operational amplifier chip U2D. Pin 1 of the sixth capacitor C1 is connected to pin 1 of the fifth operational amplifier chip U2C, and pin 2 of the sixth capacitor C1 is connected to pin 2 of the seventeenth resistor R5. Pin 1 of the seventh capacitor C2 is connected to signal ground, and pin 2 of the seventh capacitor C2 is connected to pin 3 of the fifth operational amplifier chip U2C. Pin 1 of the fourth diode D1A is connected to signal ground, and pin 2 of the fourth diode D1A is connected to pin 3 of the sixth operational amplifier chip U2D. Pin 1 of the fifth diode D1B is connected to pin 3 of the sixth operational amplifier chip U2D, and pin 2 of the fifth diode D1B is connected to the positive voltage signal VCC. Pin 1 of the third operational amplifier chip U2A is connected to pin 2 of the third operational amplifier chip U2A, pin 4 of the third operational amplifier chip U2A is connected to the negative voltage signal VDD, and pin 8 of the third operational amplifier chip U2A is connected to the positive voltage signal VSS. Pin 1 of the sixth operational amplifier chip U2D is connected to pin 2 of the sixth operational amplifier chip U2D. Pin 2 of the first adjustable DC voltage source V1 is connected to signal ground.
[0043] like Figure 6 As shown, the external hardware pre-scaling interface circuit includes a twenty-first resistor R9, a twenty-second resistor R10, a twenty-third resistor R11, a twenty-fourth resistor R12, a twenty-fifth resistor R13, a first counter chip U4, a first dual-input port element IN, and a first five-output port element OUT. The first dual-input port element IN receives the output signal of the conditioning circuit of the preamplifier, and the first five-output port element OUT outputs the signal to the digital signal processor DSP.
[0044] Among them, pin 1 of the 21st resistor R9 is connected to pin 1 of the first dual-input port element IN, and pin 2 of the 21st resistor R9 is connected to pin 14 of the first counter chip U4; pin 1 of the 22nd resistor R10 is connected to pin 12 of the first counter chip U4, and pin 2 of the 22nd resistor R10 is connected to pin 1 of the first five-output port element OUT; pin 1 of the 23rd resistor R11 is connected to pin 9 of the first counter chip U4, and pin 2 of the 23rd resistor R11 is connected to pin 2 of the first five-output port element OUT; pin 1 of the 24th resistor R12 is connected to the first counter chip U4 Pin 8 of the 24th resistor R12 is connected to pin 3 of the first five output port element OUT; Pin 1 of the 25th resistor R13 is connected to pin 11 of the first counter chip U4, and Pin 2 of the 25th resistor R13 is connected to pin 4 of the first five output port element OUT; Pin 2 of the first dual-input port element IN is connected to the signal ground; Pin 5 of the first five output port element OUT is connected to the signal ground; Pin 1 of the first counter chip U4 is connected to pin 12 of the first counter chip U4; Pin 2 of the first counter chip U4 is connected to the signal ground, and Pin 3 of the first counter chip U4 is connected to the signal ground.
[0045] In this utility model, for components with no functional difference between the two ports, such as ordinary resistors, inductors, and capacitors, the pin markings are based on the placement position in the simulation circuit: if placed vertically, the lower end is marked as pin 1 and the upper end is marked as pin 2; if placed horizontally, the left end is marked as pin 1 and the right end is marked as pin 2.
[0046] For special types of resistors: For sliding rheostats, the sliding end of the pointer is marked as pin 1, and the end connected to the fixed part of the circuit is marked as pin 2. The port corresponding to the resistor part short-circuited by the sliding pointer and its wires does not play a role in the circuit, so the pin is not marked on this end; for potentiometers, the sliding end of the pointer is marked as pin 1, and the two ends connected to the fixed part of the circuit are marked as pins 2 and 3 respectively, referring to the marking method for ordinary resistors.
[0047] For an adjustable DC voltage source, the positive voltage output terminal is marked as pin 1 and the negative voltage output terminal is marked as pin 2.
[0048] For all diodes, label the positive terminal as pin 1 and the negative terminal as pin 2.
[0049] For all transistors, label the emitter as pin 1, the base as pin 3, and the collector as pin 2.
[0050] For all operational amplifier chips, the output terminal is marked as pin 1, the inverting input terminal is marked as pin 2, the non-inverting input terminal is marked as pin 3, the negative power supply terminal is pin 4, and the positive power supply terminal is pin 8.
[0051] For all counter chips, the clock input of the 2nd, 3rd, and 4th-level counters is marked as pin 1, the two reset pins are marked as pins 2 and 3 respectively, the counting output status terminal of the 3rd-level trigger is marked as pin 8, the counting output status terminal of the 2nd-level trigger is marked as pin 9, the counting output status terminal of the 4th-level trigger is marked as pin 11, the counting output status terminal of the 1st-level trigger is marked as pin 12, and the clock input of the 1st-level counter is marked as pin 14.
[0052] In this embodiment, Figure 7 As shown in the figure, the signal output by the preamplifier's conditioning circuit is first input into an external hardware prescaler interface circuit for frequency reduction, adapting the signal frequency to the measurement range of the input capture module of the digital signal processor (DSP) used in the magnetic levitation motor rotor displacement control system, thereby avoiding measurement errors caused by high-frequency signals. The signal is then transmitted to the DSP's internal software prescaler for further frequency division. After this processing, the signal is sent to the DSP's eCAP module, which captures the rising or falling edges of the signal to calculate the signal period, corresponding to the sensor's current oscillation frequency, and obtain the target displacement signal.
[0053] In this embodiment, the eddy current displacement sensor of the magnetic levitation motor passes a high-frequency alternating current through the eddy current coil 1 in the sensor probe to generate a high-frequency alternating magnetic field. When the conductor to be measured, i.e. the rotor, enters the magnetic field, eddy currents are induced on its surface. These eddy currents will in turn generate an alternating magnetic field in the opposite direction to the original magnetic field, thereby changing the circuit parameters such as the mutual inductance and equivalent impedance of the eddy current coil 1. The change in the impedance of the eddy current coil 1 is closely related to the gap between the end face of the probe housing 2 and the rotor surface. When the gap decreases, the eddy current effect is enhanced and the change in the coil impedance is more significant; conversely, when the gap increases, the eddy current effect is weakened and the impedance change is not obvious. This characteristic can be used to determine the specific displacement of the rotor.
[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope defined by the present invention.
Claims
1. A magnetic levitation motor eddy current displacement sensor based on an external hardware pre-scaling interface, characterized by: It includes sensor probe, preamplifier and external hardware pre-scaling interface circuit; One end of the sensor probe is opposite to the conductor to be measured, and the other end of the sensor probe is connected to the input end of the preamplifier; the output end of the preamplifier is connected to the input end of the external hardware pre-scaling interface circuit; the output end of the external hardware pre-scaling interface circuit is connected to the input end of the magnetic levitation motor rotor displacement control system.
2. The magnetic levitation motor eddy current displacement sensor based on an external hardware pre-scaling interface according to claim 1 is characterized in that: The sensor probe includes an eddy current coil, a printed circuit board, a coaxial cable and an adapter; the eddy current coil is connected to the printed circuit board through a wire, the printed circuit board and the coaxial cable are electrically connected to the adapter, and the adapter is electrically connected to the preamplifier.
3. The magnetic levitation motor eddy current displacement sensor based on an external hardware pre-scaling interface according to claim 2, characterized in that: The sensor probe further comprises a probe housing, and the eddy current coil and the printed circuit board are both arranged inside the probe housing.
4. The magnetic levitation motor eddy current displacement sensor based on an external hardware pre-scaling interface according to claim 3 is characterized in that: The outer surface of the probe housing is provided with a position adjustment thread, and the clamping nut is rotated into the probe housing through the position adjustment thread.
5. The magnetic levitation motor eddy current displacement sensor based on an external hardware pre-scaling interface according to claim 2, characterized in that: The sensor probe further includes a cable armor wrapped around the coaxial cable.
6. The magnetic levitation motor eddy current displacement sensor based on an external hardware pre-scaling interface according to claim 1, characterized in that: The preamplifier includes an oscillation circuit, a detection circuit and a conditioning circuit electrically connected in sequence; the input end of the oscillation circuit is electrically connected to the adapter in the sensor probe, and the output end is connected to the input end of the detection circuit; the output end of the detection circuit is connected to the input end of the conditioning circuit; the output end of the conditioning circuit is electrically connected to the external hardware pre-dividing interface circuit.
7. The magnetic levitation motor eddy current displacement sensor based on an external hardware pre-scaling interface according to claim 6, characterized in that: The external hardware pre-scaling interface circuit includes a twenty-first resistor R9, a twenty-second resistor R10, a twenty-third resistor R11, a twenty-fourth resistor R12, a twenty-fifth resistor R13, a first counter chip U4, a first dual-input port element IN and a first five-output port element OUT; wherein the first dual-input port element IN receives the output signal of the conditioning circuit of the preamplifier; one end of the twenty-first resistor is connected to the first dual-input port element IN, and the other end is connected to the first counter chip U4; one end of the twenty-second resistor R10 is connected to the first counter chip U4, and the other end is connected to the first five-output port element OUT; one end of the twenty-third resistor R11 is connected to the first counter chip U4, and the other end is connected to the first five-output port element OUT; one end of the twenty-fourth resistor R12 is connected to the first counter chip U4, and the other end is connected to the first five-output port element OUT; one end of the twenty-fifth resistor R13 is connected to the first counter chip U4, and the other end is connected to the first five-output port element OUT; the first dual-input port element IN and the first five-output port element OUT both have one port connected to the signal ground.