Magnetic suspension motor rotor detection mechanism, detection method and electronic equipment

Abstract

The invention discloses a magnetic suspension motor rotor detection mechanism, a detection method and electronic equipment. The mechanism comprises an eddy current sensor, a differential detection circuit, a digital potentiometer, an MCU (Microprogrammed Control Unit) and a resistance measurement loop which are symmetrically arranged. The digital potentiometer is controlled by the MCU to automatically complete zero position and full position calibration, so that the operation convenience is improved; the state of a sensor coil is monitored in real time by using a resistance measurement loop, fault diagnosis and online compensation based on a temperature coefficient are realized, the temperature drift is effectively inhibited, and the measurement precision is ensured; a rotor displacement signal and a Hall sensor detection angle are accurately extracted in combination with a differential amplification technology, and the reliability and stability of the system under complex working conditions are comprehensively improved.

Description

Technical Field

[0001] This application relates to the field of displacement sensor technology, and more specifically, to a magnetic levitation motor rotor detection mechanism, detection method, and electronic equipment. Background Technology

[0002] Eddy current displacement sensors are non-contact sensors with advantages such as reliable operation, convenient use and maintenance, long lifespan, high repeatability, good dynamic characteristics, simple structure, and small size. They are particularly suitable for high-speed displacement measurement in harsh environments such as high temperature, high humidity, and oil contamination. The basic working principle of an eddy current sensor is electromagnetic induction. A coil in the sensor probe is supplied with a high-frequency alternating current, generating an alternating magnetic field. When the magnetic field approaches a metallic target, eddy currents are induced on the target surface. These eddy currents then generate an alternating magnetic field in the opposite direction, which reacts on the probe coil. This process changes the coil's impedance, including resistance and inductance. Through the microprocessor and digital processing inside the eddy current sensor, the detected nonlinear signal can be calculated and converted in real time at high speed, directly outputting a standardized voltage or current signal that is linearly proportional to the distance.

[0003] Eddy current sensors are commonly used in magnetic levitation motors to detect rotor position and whether misalignment has occurred. Different magnetic levitation motors may differ in material and size, thus the eddy current effect they generate may also vary. Therefore, zero-position and full-position calibration must be performed during initial use. Existing calibration methods are limited, mostly involving adjusting the resistor in the voltage divider network at the output. Zero-position and full-position calibrations require repeated adjustments. Summary of the Invention

[0004] The purpose of this application is to provide a magnetic levitation motor rotor detection mechanism, detection method, and electronic device to solve the above-mentioned problems existing in the prior art and realize the rapid debugging of eddy current sensors.

[0005] Firstly, a magnetic levitation motor rotor detection mechanism is provided, comprising:

[0006] At least two pairs of eddy current sensors, each pair of eddy current sensors being symmetrically arranged along the rotor axis;

[0007] The differential detection circuit is configured to differentially amplify the signals from a pair of eddy current sensors. It includes a first operational amplifier and a second operational amplifier. The input terminals of the first operational amplifier are respectively used to input the signals from the pair of eddy current sensors, and the output terminal is connected to the inverting input terminal of the second operational amplifier. The output signal of the second operational amplifier is sent to the main control system for signal processing.

[0008] The first potentiometer is connected to the non-inverting input of the second operational amplifier to set the bias voltage.

[0009] The second potentiometer, located in the feedback branch of the second operational amplifier, is used to adjust the amplification gain of the second operational amplifier.

[0010] Furthermore, it also includes an MCU control unit, wherein the first potentiometer and the second potentiometer are digital potentiometers, the MCU control unit communicates bidirectionally with the first potentiometer and the second potentiometer, and the MCU control unit is connected to the main control system.

[0011] Furthermore, it also includes an electrical measurement circuit and an analog switch. The resistance measurement circuit is used to detect the resistance value of the eddy current sensor, and the analog switch is used to control the connection and disconnection between the eddy current sensor and the differential detection circuit. The resistance measurement circuit is connected to the MCU control unit. When the resistance value of the eddy current sensor exceeds the set range, the MCU control unit sends an abnormality alert to the main control system.

[0012] Furthermore, it also includes two pairs of Hall sensors and a differential amplifier circuit. Each pair of Hall sensors is symmetrically arranged along the rotor shaft, and the line connecting two adjacent Hall sensors to the rotor shaft is at 90°. The differential amplifier circuit performs differential and amplification operations on the signals of each pair of Hall sensors and then sends them to the main control system.

[0013] Secondly, a method for detecting the rotor of a magnetic levitation motor is provided, employing the magnetic levitation motor rotor detection mechanism described in the first aspect, the method comprising:

[0014] Move the rotor of the motor under test so that its shaft center coincides with the stator shaft center of the motor under test. Set the resistance value R1 of the first potentiometer through the MCU control unit so that the output value of the second operational amplifier is zero.

[0015] Move the rotor of the motor under test until the displacement of its shaft center in the corresponding detection direction of the eddy current sensor reaches the maximum range X. max And record the current output value U of the second operational amplifier. max And the resistance value R2 of the second potentiometer;

[0016] The resistance value X max And U max Substitute the preset function model F to calculate the rotor shaft displacement X and the output value V of the second operational amplifier. out The mapping relationship between them, where the function model F is used to describe the relationship between the output value of the second operational amplifier and the differential voltage ΔU of the corresponding two eddy current sensors, as well as the relationship between the displacement X and ΔU;

[0017] During testing, the output value V of the second operational amplifier is obtained through the main control system. out Based on the displacement X and the output value V of the second operational amplifier outThe mapping relationship between them is used to output the rotor displacement value.

[0018] Furthermore, the function model F is:

[0019] V out / V in =aR2+b

[0020] V in =ΔU×c

[0021] X = f(ΔU)

[0022] Where a and b are circuit parameters, determined by the voltage divider resistor network of the negative feedback path and the input impedance of the inverting input terminal, c is the differential amplification gain of the first operational amplifier, and X=f(ΔU) depends on the characteristics of the eddy current sensor.

[0023] Furthermore, the coil resistance of the eddy current sensor is measured in real time through a resistance measurement circuit;

[0024] The real-time temperature of the eddy current sensor is calculated based on the measured resistance of the sensor coil, the coil resistance at room temperature, and the temperature coefficient of the enameled wire.

[0025] Based on the relationship between the real-time resistance of the coil and the resistance of the coil at room temperature, the resistance of the second potentiometer is adjusted to make the gain of the second operational amplifier change accordingly for temperature compensation.

[0026] Thirdly, an electronic device is provided, which includes a processor, a communication interface, a memory, and a communication bus, wherein the processor, the communication interface, and the memory communicate with each other through the communication bus;

[0027] Memory, used to store computer programs;

[0028] When a processor executes a program stored in memory, it implements any of the steps described in the first aspect above.

[0029] Beneficial effects: By integrating a digital potentiometer, a two-stage differential amplifier circuit, and a resistance monitoring loop, rapid and automated calibration of the rotor at zero and full positions is achieved, significantly improving operational convenience. At the same time, by using real-time measurement of the eddy current sensor coil resistance for temperature compensation and fault diagnosis, the impact of temperature drift on measurement accuracy is effectively reduced, and the real-time monitoring capability for abnormal states such as open circuits and short circuits of the sensor is enhanced, thereby comprehensively improving the accuracy, reliability, and stability of the detection system. Attached Figure Description

[0030] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of the structure of the magnetic levitation motor rotor detection mechanism provided in the embodiments of this application;

[0032] Figure 2 This is a functional block diagram of the magnetic levitation motor rotor detection mechanism provided in the embodiments of this application;

[0033] Figure 3 This is a schematic diagram of the oscillation circuit in the magnetic levitation motor rotor detection mechanism provided in the embodiments of this application;

[0034] Figure 4 The circuit diagram of the differential amplifier circuit in the magnetic levitation motor rotor detection mechanism provided in the embodiment of this application;

[0035] Figure 5 A block diagram of the analog switch circuit in the magnetic levitation motor rotor detection mechanism provided in this application embodiment;

[0036] Figure 6 This is a schematic diagram of the resistance measurement circuit in the magnetic levitation motor rotor detection mechanism provided in an embodiment of this application.

[0037] Figure 7 A schematic diagram of the Hall effect detection principle in the magnetic levitation motor rotor detection mechanism provided in this embodiment of the application. Detailed implementation details.

[0038] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. Unless otherwise defined, the technical or scientific terms used in this application should have the ordinary meaning understood by those skilled in the art. The words "first," "second," and similar terms used in this application do not indicate any order, quantity, or importance, but are only used to distinguish different components. The words "comprising" or "including," etc., mean that the element or object preceding the word covers the element or object listed after the word and its equivalents, but do not exclude other elements or objects. The words "connected," "coupled," or "connected," etc., are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up," "down," "left," "right," etc., are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0039] The magnetic levitation motor rotor detection mechanism provided in this application embodiment is as follows: Figure 1 and Figure 2 As shown, it includes a demodulation board 7, a flat cable 6, two pairs of eddy current sensors 1, two pairs of Hall sensors 2, and a temperature sensor 5. The flat cable is used to connect the various sensors to the demodulation board. Each pair of eddy current sensors and Hall sensors are symmetrically arranged along the axis of the rotor 3. That is, the eddy current sensors are spaced 90° apart, and each pair of eddy current sensors is 180° apart. Therefore, the position of the rotor axis can be detected in both vertical and horizontal directions. The spatial arrangement of the Hall sensors is the same as that of the eddy current sensors, with a distance of 45° between the Hall sensors and the eddy current sensors. Figure 3 As shown, the eddy current sensors generate oscillation signals from a 1MHz active crystal oscillator, which are then applied to four eddy current sensors via a 2.7KΩ current-limiting resistor. Each sensor can be mounted on stator 4.

[0040] The demodulation board has a built-in signal conditioning circuit to condition the sensor signal. This signal conditioning circuit includes a differential detection circuit, such as... Figure 4As shown, the differential detection circuit is configured to differentially amplify the signals from a pair of eddy current sensors. It includes a first operational amplifier and a second operational amplifier for two-stage amplification. The input terminals of the first operational amplifier are used to receive the signals from the pair of eddy current sensors, and its output terminal is connected to the inverting input terminal of the second operational amplifier. The first operational amplifier performs a first-stage amplification, and the output signal from the second operational amplifier is sent to a main control system for signal processing. The main control system can be a host computer or a DSP digital signal processing system. After digitizing the acquired voltage signal, a unique rotor signal is obtained. The differential detection circuit also includes a first potentiometer, a second potentiometer, and an MCU control unit, which is a microcontroller. The first potentiometer is connected to the non-inverting input terminal of the second operational amplifier to set the bias voltage; the second potentiometer is located in the feedback branch of the second operational amplifier and is used to adjust the amplification gain of the second operational amplifier. In this embodiment, the first and second potentiometers are digital potentiometers, and the MCU control unit communicates bidirectionally with both the first and second potentiometers. The MCU control unit is connected to the main control system. By precisely setting the voltage at the non-inverting input terminal using the first potentiometer, a compensation voltage equal in magnitude but opposite in direction to Vos is injected, thereby accurately zeroing the output voltage of the second operational amplifier to the desired static operating point. This enables rapid rotor zero-position calibration. The second potentiometer allows for precise and rapid setting of the gain of the second operational amplifier, further amplifying the differential voltage of the eddy current sensor to the required factor, thus adapting to different models of magnetic levitation motors.

[0041] The signal conditioning circuit also includes an electrical measurement circuit and analog switches, such as... Figure 5 As shown, the model is CD4051, an 8-channel analog multiplexer / demultiplexer. Its on / off state is controlled by digital signals from the MCU control unit. The four negative terminals of the eddy current sensor are connected in parallel and controlled by an analog switch. During normal rotor position measurement, the analog switch is on, creating a circuit at the negative terminals. When measuring coil resistance, the analog switch is off, and the eddy current sensor stops displacement measurement, preventing resistance deviation.

[0042] The resistance measurement circuit is used to detect the resistance value of the eddy current sensor, such as... Figure 6 As shown, the coil resistance is measured using the two-wire resistance thermometer method with the ADS1120 chip. The ADS1120 chip converts the weak analog sensor signal into high-resolution digital data and sends it to the MCU control unit. When the resistance value of the eddy current sensor exceeds the set range (such as when there is an inter-turn short circuit, open circuit fault inside the sensor, or incorrect connection, loose connection, or broken wire in the sensor circuit wiring, the resistance value of the eddy current sensor will change abruptly), the MCU control unit sends an abnormality alert to the main control system, such as triggering a high level on the microcontroller pin RD6 (its normal operating state is low voltage).

[0043] Hall effect detection circuit, such as Figure 7 As shown, the Hall sensors are model A1322, arranged at 90° intervals. Two Hall sensors installed at 180° are differentially amplified to output the rotor angle signal to the backend system. The main control system calculates the rotor angle by performing arctangent calculation on the demodulated Hall sensors.

[0044] Based on the unified inventive concept, this application also discloses a method for detecting the rotor of a magnetic levitation motor, which employs the magnetic levitation motor rotor detection mechanism described above. The method includes the following steps:

[0045] Zero-point calibration: Move the rotor of the motor under test so that its shaft center coincides with the stator shaft center of the motor under test. Set the resistance value of the first potentiometer through the MCU control unit and inject a compensation voltage that is equal in magnitude and opposite in direction to Vos. This will accurately adjust the output voltage of the second operational amplifier to the desired static operating point, so that the output value of the second operational amplifier is zero.

[0046] Full-range calibration: Move the rotor of the motor under test until the displacement of its shaft center in the corresponding eddy current sensor detection direction reaches the maximum range X. max And record the current output value U of the second operational amplifier. max And the resistance value R2 of the second potentiometer;

[0047] Model building: The main control system will use the maximum range X max And U max Substitute the preset function model F to calculate the rotor shaft displacement X and the output value V of the second operational amplifier. out The mapping relationship between them is described by the function model F, which describes the relationship between the output value of the second operational amplifier and the differential voltage ΔU of the two corresponding eddy current sensors, as well as the relationship between the displacement X and ΔU. The function model F is:

[0048] V out / V in =aR2+b

[0049] V in =ΔU×c

[0050] X = f(ΔU)

[0051] Where a and b are circuit parameters, determined by the voltage divider resistor network of the negative feedback path and the input impedance of the inverting input terminal, c is the differential amplification gain of the first operational amplifier, which is a circuit characteristic, and X=f(ΔU) depends on the characteristics of the eddy current sensor, which is generally a linear relationship.

[0052] During testing, the output value V of the second operational amplifier is obtained through the main control system. outBased on the displacement X and the output value V of the second operational amplifier out The mapping relationship between them is used to output the rotor displacement value.

[0053] The temperature of an eddy current sensor can be detected by the sensor or inferred. In this embodiment, the temperature coefficient of the enameled wire of the eddy current sensor is 0.4% / ℃. The resistance measurement circuit measures the coil resistance of the eddy current sensor in real time. Based on the measured coil resistance at room temperature and the temperature coefficient of the enameled wire, the real-time temperature of the eddy current sensor is calculated.

[0054] Based on the relationship between the real-time resistance of the coil and its resistance at room temperature, adjust the resistance of the second potentiometer to correspondingly change the gain of the second operational amplifier. For example, if a 10% increase in resistance results in a 10% increase in output voltage, the second operational amplifier needs to be adjusted to reduce its gain to 10 / 11 of its original value. It should be noted that the changes in the resistance and output voltage of the eddy current sensor are determined by the sensor's characteristics; the effect of temperature on the output voltage can be found in the product manual.

[0055] Beneficial effects: First, the system uses digital potentiometers (controlled by an MCU) instead of traditional mechanical potentiometers, enabling automatic and precise setting of bias voltage and operational amplifier gain. This allows for rapid, online calibration of the rotor's mechanical zero and full positions, greatly simplifying on-site operation and improving calibration efficiency and convenience. It is also compatible with different magnetic levitation motors. Second, the system integrates a resistance measurement circuit. Through analog switching (CD4051), it can monitor the resistance of the eddy current sensor coil in real time. This not only triggers an alarm immediately when the sensor experiences inter-turn short circuits, open circuits, or wiring faults, improving the system's fault diagnosis and safety monitoring capabilities, but also calculates the sensor temperature in real time based on coil resistance changes. The MCU dynamically adjusts the amplification gain, effectively compensating for the impact of temperature drift on measurement accuracy and ensuring long-term data output stability. Finally, by processing the symmetrically arranged sensor signals through a differential amplifier circuit, common-mode noise is effectively suppressed. Combined with the main control system's algorithm calculation, high-precision, anti-interference measurement of rotor displacement and angle is ultimately achieved. Overall, this improves the accuracy, reliability, stability, and operation and maintenance efficiency of the detection system.

[0056] Based on the unified inventive concept, this application can also provide an electronic device, which includes a processor, a communication interface, a memory, and a communication bus, wherein the processor, the communication interface, and the memory communicate with each other through the communication bus;

[0057] Memory, used to store computer programs;

[0058] The processor implements the above method when executing a program stored in memory.

[0059] The communication bus mentioned above can be a peripheral component interconnection standard bus or an Extended Industry Standard Architecture (EISA) bus, etc. This communication bus can be divided into address bus, data bus, control bus, etc. For ease of illustration, only one thick line is used to represent it in the diagram, but this does not mean that there is only one bus or one type of bus.

[0060] The communication interface is used for communication between the aforementioned electronic devices and other devices.

[0061] The memory may include random access memory (RAM) or non-volatile memory (NVM), such as at least one disk storage device. Optionally, the memory may also be at least one storage device located remotely from the aforementioned processor.

[0062] The processors mentioned above can be general-purpose processors, including central processing units, network processors, etc.; they can also be digital signal processors (DSPs), application-specific integrated circuits, field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components.

[0063] In another embodiment provided in this application, a computer-readable storage medium is also provided, which stores instructions that, when executed on a computer, cause the computer to perform any of the methods described in the above embodiments.

[0064] Those skilled in the art will understand that the embodiments in this application can be provided as methods, systems, or computer program products. Therefore, the embodiments in this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the embodiments in this application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0065] This application describes embodiments of methods, apparatus (systems), and computer program products according to embodiments of this application with reference to flowchart illustrations and / or block diagrams. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0066] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0067] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0068] Although preferred embodiments have been described in this application, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the embodiments of this application.

[0069] Obviously, those skilled in the art can make various modifications and variations to the embodiments of this application without departing from the spirit and scope of the embodiments of this application. Therefore, if these modifications and variations to the embodiments of this application fall within the scope of the claims in this application and their equivalents, then this application also intends to include these modifications and variations.

Claims

1. A magnetic levitation motor rotor detection mechanism characterized by comprising: The method comprises: The method comprises: The function model F is: X=f (ΔU) Wherein, a, b are circuit parameters, determined by the voltage dividing resistor network of the negative feedback path and the input impedance of the reverse input end, c is the differential amplification gain of the first operational amplifier, and X=f (ΔU) depends on the characteristics of the eddy current sensor.

2. The magnetic levitation motor rotor detection mechanism of claim 1, wherein, The electronic device comprises a processor, a communication interface, a memory, and a communication bus, wherein the processor, the communication interface, and the memory communicate with each other through the communication bus.

3. The magnetic levitation motor rotor detection mechanism of claim 2, wherein, The memory is used to store a computer program.

4. The magnetic levitation motor rotor detection mechanism of claim 3, wherein, The processor is used to execute the program stored on the memory, and the method of any one of claims 5-7 is realized.

5. A magnetic levitation motor rotor detecting method using the magnetic levitation motor rotor detecting mechanism according to any one of claims 2 to 5, characterized by, ​ ​ The rotor of the motor to be tested is moved to make the displacement of its axis in the direction of detection of the corresponding eddy current sensor reach the maximum range X max The current output value U of the second operational amplifier is recorded max And the resistance R2 of the second potentiometer The resistance value X max and U max is brought into a preset function model F, and a mapping relationship between the rotor shaft center displacement X and the output value V out of the second operational amplifier is calculated, wherein the function model F is used to describe the relationship between the output value of the second operational amplifier and the differential voltage ΔU of the corresponding two eddy current sensors and the relationship between the displacement X and ΔU. When detecting, the output value V of the second operational amplifier is acquired by the master control system out , and the displacement value of the rotor is output according to the mapping relationship between the displacement X and the output value V of the second operational amplifier out .

6. The method of claim 5, wherein the step of detecting the rotor position of the magnetic levitation motor is performed by using a magnetic sensor. ​ V out / V in =aR2+b V in =ΔU×c ​ ​ 7. The method of claim 6, wherein the step of detecting the rotor position of the magnetic levitation motor is performed by using a magnetic sensor. ​ ​ ​ ​ 8. An electronic device, comprising: ​ ​ ​

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