Magnetic suspension motor rotor displacement detection system

Abstract

The invention belongs to the technical field of magnetic suspension motors, and discloses a magnetic suspension motor rotor displacement detection system, which comprises an eddy current sensor, a displacement signal processing circuit and a magnetic suspension motor controller, the displacement signal processing circuit comprises a first-stage signal amplification circuit and a second-stage signal amplification circuit, the input end of the first-stage signal amplification circuit is connected with the signal output end of the eddy current sensor, and the output end of the first-stage signal amplification circuit is connected with the input end of the second-stage signal amplification circuit; the output end of the secondary signal amplification circuit is connected with the input end of the magnetic suspension motor controller, and the output end of the magnetic suspension motor controller is connected with the magnetic suspension motor; according to the invention, the position signal of the motor rotor can be processed stably and continuously, the electric signal required by the magnetic suspension motor controller can be output stably, and the safety, reliability and stability of the operation of the magnetic suspension motor are ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of magnetic levitation motors, and more particularly to a rotor displacement detection system for a magnetic levitation motor. Background Art

[0002] When the rotor of a magnetic levitation motor rotates while levitating, it is a very unstable open-loop system. That is, under the influence of various factors at different times, the position of the motor rotor will be different. In order to be able to monitor the position of the rotor in real time and make corresponding controls so that the motor rotor can maintain a relatively stable levitation position, it is crucial for the stable operation of the magnetic levitation motor. There are various position sensors in the world for monitoring the position of the rotor of a magnetic levitation motor, and the eddy current sensor is one of them.

[0003] During the rotation of the rotor in a magnetic levitation motor, due to the uncertain offset of the position, different and irregular eddy current signals will be generated. The eddy current displacement sensor can capture these tiny eddy current signals in real time and convert them into corresponding regular electrical signals.

[0004] However, generally speaking, these electrical signals are relatively weak and there is relatively large interference. If these unprocessed eddy current signals are directly transmitted to the magnetic levitation motor controller, it will greatly affect the control effect of the magnetic levitation motor controller on the rotor levitation, and further affect the stability of the motor operation. In the lightest case, it will cause damage to the motor, and in the most serious case, it will lead to production suspension, personal injury and death, resulting in significant economic property losses. Summary of the Invention

[0005] The main technical problem to be solved by the present invention is to provide a rotor displacement detection system for a magnetic levitation motor, which can stably and continuously process the motor rotor position signal and stably output the electrical signal required by the magnetic levitation motor controller, ensuring the safety, reliability and stability of the operation of the magnetic levitation motor.

[0006] To solve the above technical problem, the present invention provides the following technical solutions: A rotor displacement detection system for a magnetic levitation motor includes an eddy current sensor, a displacement signal processing circuit and a magnetic levitation motor controller. The eddy current sensor is installed in the magnetic levitation motor. The displacement signal processing circuit includes a first-stage signal amplification circuit and a second-stage signal amplification circuit. The input end of the first-stage signal amplification circuit is connected to the signal output end of the eddy current sensor, the output end of the first-stage signal amplification circuit is connected to the input end of the second-stage signal amplification circuit, the output end of the second-stage signal amplification circuit is connected to the input end of the magnetic levitation motor controller, and the output end of the magnetic levitation motor controller is connected to the magnetic levitation motor.

[0007] The following is a further optimization of the above technical solution by the present invention: The first-stage signal amplification circuit includes a first amplifier. The second pin of the first amplifier is connected to the negative power supply input through a first resistor R1 and is connected to the first pin of the first amplifier through a second resistor. The third pin of the first amplifier is connected to the positive power supply input through a third resistor and is grounded through a fourth resistor.

[0008] Further optimization: The second-stage signal amplification circuit includes a second amplifier and a potentiometer. The sixth pin of the second amplifier is connected to the output end of the first-stage signal amplification circuit through a fifth resistor and is connected to the output end of the second-stage signal amplification circuit through a sixth resistor. The fifth pin of the second amplifier is connected to the sliding end of the potentiometer through a ninth resistor. The first fixed end of the potentiometer is connected to +10V DC voltage through a seventh resistor, and the second fixed end of the potentiometer is connected to -10V DC voltage through an eighth resistor. The seventh pin of the second amplifier is connected to the output end of the second-stage signal amplification circuit through a tenth resistor.

[0009] Further optimization: The first-stage signal amplification circuit further includes a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, and a fifth capacitor. The first capacitor is arranged in parallel with the first resistor, and the second pin of the first amplifier is grounded through the first capacitor. The second capacitor is arranged in parallel with the second resistor, and the second pin of the first amplifier is connected to the first pin of the first amplifier through the second capacitor. The third pin of the first amplifier is grounded through the third capacitor and the fourth resistor arranged in parallel. The fourth pin of the first amplifier is connected to +15V DC voltage and is grounded through the fourth capacitor. The eleventh pin of the first amplifier is connected to -15V DC voltage and is grounded through the fifth capacitor.

[0010] Further optimization: The second-stage signal amplification circuit further includes a sixth capacitor and a seventh capacitor. The sixth capacitor is arranged in parallel with the sixth resistor, and the sixth pin of the second amplifier is connected to the output end of the second-stage signal amplification circuit through the sixth capacitor. The seventh capacitor is arranged in series with the tenth resistor, and the seventh pin of the second amplifier is grounded through the tenth resistor and the seventh capacitor.

[0011] Further optimization: The resistance values of the first resistor, the second resistor, the third resistor, and the fourth resistor are all the same.

[0012] Further optimization: The resistance values of the fifth resistor, the sixth resistor, the seventh resistor, the eighth resistor, and the potentiometer are all the same.

[0013] The present invention adopts the above technical solutions and has the following beneficial effects: 1. The present invention adopts the above technical solution, with a clever concept. It uses a stable and reliable displacement signal processing circuit to amplify and filter the eddy current signal in order to obtain a clean and stable electrical signal, and transmits the amplified and stable electrical signal to the magnetic levitation motor controller. After being processed by the magnetic levitation motor controller, an accurate controllable signal is output and fed back to the magnetic levitation motor to adjust the suspension position of the rotor, thereby ensuring the normal and stable operation of the magnetic levitation motor.

[0014] 2. Both the primary signal amplification circuit and the secondary signal amplification circuit use an operational amplifier as the main component, adjust the signal using a potentiometer, and use calculated resistors and capacitors as bias and filtering compensation components to continuously and stably process the eddy current signal into a stable, clean, and amplified electrical signal, ensuring the stable rotation of the rotor and improving the safety and reliability of the motor operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0016] Figure 1 It is the flowchart of the displacement detection system in the embodiment of the present invention; Figure 2 It is the circuit diagram of the displacement signal processing in the first embodiment of the present invention; Figure 3 It is the circuit diagram of the displacement signal processing in the second embodiment of the present invention.

[0017] In the figure: 1. Eddy current sensor; 2. Magnetic levitation motor controller; 3. Magnetic levitation motor; 4. Displacement signal processing circuit; 41. Primary signal amplification circuit; 42. Secondary signal amplification circuit. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0018] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0019] Embodiment 1

[0020] As Figure 1 and Figure 2As shown together, a magnetic levitation motor rotor displacement detection system includes an eddy current sensor 1, a displacement signal processing circuit 4, and a magnetic levitation motor controller 2. The eddy current sensor 1 is installed inside the magnetic levitation motor 3. The displacement signal processing circuit 4 includes a first-stage signal amplification circuit 41 and a second-stage signal amplification circuit 42. The input end of the first-stage signal amplification circuit 41 is connected to the signal output end of the eddy current sensor 1. The output end of the first-stage signal amplification circuit 41 is connected to the input end of the second-stage signal amplification circuit 42. The output end of the second-stage signal amplification circuit 42 is connected to the input end of the magnetic levitation motor controller 2. The output end of the magnetic levitation motor controller 2 is connected to the magnetic levitation motor 3.

[0021] In this embodiment, this displacement signal processing circuit 4 is mainly used for processing the signal of the eddy current sensor 1. It is mainly composed of two-stage differential operational amplifier circuits, and finally outputs an adjustable voltage signal, and the size of the output signal is changed by the potentiometer RP.

[0022] In this embodiment, the displacement signal processing circuit 4 can process the displacement signal monitored by the eddy current sensor 1 in real time, so that the magnetic levitation motor controller 2 can quickly adjust the control parameters to realize the adjustment of the rotor position in the magnetic levitation motor 3, thereby improving the stability of the operation of the magnetic levitation motor 3.

[0023] Moreover, this circuit can stably and continuously process the motor rotor position signal, can stably output the electrical signal required by the magnetic levitation motor controller 2, keeps the rotor rotating stably, and improves the safety and reliability of the operation of the magnetic levitation motor 3.

[0024] The first-stage signal amplification circuit 41 includes a first amplifier U1. The second pin of the first amplifier U1 is connected to the negative power supply input through a first resistor R1 and is connected to the first pin of the first amplifier U1 through a second resistor R2. The third pin of the first amplifier U1 is connected to the positive power supply input through a third resistor R3 and is grounded through a fourth resistor R4.

[0025] In this embodiment, the first amplifier U1 can adopt an operational amplifier of model LM224.

[0026] The secondary signal amplification circuit 42 includes a second amplifier U2 and a potentiometer RP. The sixth pin of the second amplifier U2 is connected to the output terminal of the primary signal amplification circuit 41 through a fifth resistor R5 and is connected to the output terminal of the secondary signal amplification circuit 42 through a sixth resistor R6. The fifth pin of the second amplifier U2 is connected to the sliding end of the potentiometer RP through a ninth resistor R9. The first fixed end of the potentiometer RP is connected to +10V DC voltage through a seventh resistor R7, and the second fixed end of the potentiometer RP is connected to -10V DC voltage through an eighth resistor R8. The seventh pin of the second amplifier U2 is connected to the output terminal of the secondary signal amplification circuit 42 through a tenth resistor R10.

[0027] In this embodiment, the potentiometer RP is used to adjust the magnitude of the electrical signal.

[0028] In this embodiment, the second amplifier U2 can adopt an operational amplifier of model LM224.

[0029] In this embodiment, both the primary signal amplification circuit 41 and the secondary signal amplification circuit 42 constitute differential operational amplifier circuits, which are used to amplify and filter the eddy current signals monitored by the eddy current sensor 1.

[0030] In this embodiment, the sixth resistor R6 and the tenth resistor R10 are arranged in series.

[0031] In this embodiment, the first resistor R1, the second resistor R2, the third resistor R3, the fourth resistor R4, the fifth resistor R5, the sixth resistor R6, the seventh resistor R7, the eighth resistor R8, the ninth resistor R9, the tenth resistor R10 and the potentiometer RP are used to construct the feedback circuits of the first amplifier U1 and the second amplifier U2. By selecting appropriate resistance values, the gains of the first amplifier U1 and the second amplifier U2 are adjusted, and the signal amplitudes and phases at the two input terminals of the first amplifier U1 and the second amplifier U2 are balanced.

[0032] The resistance values of the first resistor R1, the second resistor R2, the third resistor R3 and the fourth resistor R4 are all the same.

[0033] The resistance values of the fifth resistor R5, the sixth resistor R6, the seventh resistor R7, the eighth resistor R8 and the potentiometer RP are all the same.

[0034] In this embodiment, the output terminal voltage of the primary signal amplification circuit 41 is , The calculation formula of

[0035] is the voltage divided by the potentiometer RP, and the voltage range is -3.3V to +3.3V.

[0036] Output voltage of the output terminal of the motor rotor position signal processing circuit , The calculation formula is: Embodiment 2

[0037] Compared with the technical solution of Embodiment 1, the difference in Embodiment 2 is that: In this embodiment, the first amplifier U1 has a total of five pins, and its output terminal is named the first pin, its inverting input terminal is named the second pin, its non-inverting input terminal is named the third pin, its positive power supply terminal is named the fourth pin, and its negative power supply terminal is named the eleventh pin.

[0038] Similarly, in this embodiment, the second amplifier U2 uses a total of three pins, and its output terminal is named the seventh pin, its inverting input terminal is named the sixth pin, and its non-inverting input terminal is named the fifth pin.

[0039] As Figure 2 and Figure 3 jointly shown, the first-stage signal amplification circuit 41 further includes a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, and a fifth capacitor C5. The first capacitor C1 is connected in parallel with the first resistor R1, and the second pin of the first amplifier U1 is grounded through the first capacitor C1.

[0040] In this embodiment, a first resistor R1 is connected in series between the inverting input terminal of the first amplifier U1 and the negative power supply input (i.e., the signal source), and a first capacitor C1 is connected in parallel after the first resistor R1. The first resistor R1 is used to limit the input circuit and protect the inverting input terminal of the first amplifier U1. The first capacitor C1 and the first resistor R1 together form a low-pass filter to suppress high-frequency noise.

[0041] The second capacitor C2 is connected in parallel with the second resistor R2, and the second pin of the first amplifier U1 is connected to the first pin of the first amplifier U1 through the second capacitor C2.

[0042] In this embodiment, the second capacitor C2 and the second resistor R2 form an RC network. At high frequencies, the capacitive reactance of the second capacitor C2 decreases, and the feedback gain decreases, thereby suppressing the high-frequency gain and preventing self-oscillation of the first amplifier U1.

[0043] The third pin of the first amplifier U1 is grounded through the third capacitor C3 and the fourth resistor R4 connected in parallel.

[0044] In this embodiment, the third capacitor C3 and the fourth resistor R4 form an RC low-pass filter network, and its core function is AC coupling and high-frequency noise suppression.

[0045] The fourth resistor R4 provides a DC bias path to ensure the stability of the DC potential at the non-inverting input terminal. The third capacitor C3 presents a high impedance (open circuit) to DC signals, ensuring that the DC bias voltage is not affected, and presents a low impedance (short circuit) to AC signals, allowing only AC signals to pass through.

[0046] Moreover, the high-frequency noise is bypassed to the ground by the third capacitor C3 and cannot pass through the first amplifier U1, thereby suppressing the noise.

[0047] The fourth pin of the first amplifier U1 is connected to the +15V DC voltage and grounded through the fourth capacitor C4. The eleventh pin of the first amplifier U1 is connected to the -15V DC voltage and grounded through the fifth capacitor C5.

[0048] In this embodiment, the fourth capacitor C4 and the fifth capacitor C5 are set by using the power decoupling technology, which improves the stability of the power supply, reduces the noise interference and improves the circuit performance.

[0049] In this embodiment, the fourth capacitor C4 and the fifth capacitor C5 can use commercially available ceramic capacitors or tantalum capacitors.

[0050] One end of the fourth capacitor C4 is connected to the positive power supply terminal of the first amplifier U1, and the other end is grounded. One end of the fifth capacitor C5 is connected to the negative power supply terminal of the first amplifier U1, and the other end is grounded.

[0051] Both the fourth capacitor C4 and the fifth capacitor C5 present a high impedance to DC signals. Therefore, the current can pass through the positive power supply terminal and the negative power supply terminal of the first amplifier U1 to provide a stable DC operating voltage for the first amplifier U1.

[0052] However, the fourth capacitor C4 and the fifth capacitor C5 have a low impedance to high-frequency signals. High-frequency noise (such as power supply ripple, electromagnetic interference, etc.) will be bypassed to the ground through the capacitors and will not enter the first amplifier U1. Therefore, both the fourth capacitor C4 and the fifth capacitor C5 act as a "short circuit" for high-frequency noise, effectively isolating the power supply noise from the internal circuit of the first amplifier U1 and improving the purity of the signal.

[0053] The secondary signal amplification circuit 42 further includes a sixth capacitor C6 and a seventh capacitor C7. The sixth capacitor C6 is connected in parallel with the sixth resistor R6. The sixth pin of the second amplifier U2 is connected to the output terminal of the secondary signal amplification circuit 42 through the sixth capacitor C6. In this embodiment, the sixth capacitor C6, the sixth resistor R6 and the tenth resistor R10 form a low-pass filter.

[0054] The seventh capacitor C7 is connected in series with the tenth resistor R10. The seventh pin of the second amplifier U2 is grounded through the tenth resistor R10 and the seventh capacitor C7.

[0055] In this embodiment, a seventh capacitor C7 and a tenth resistor R10 are connected in series at the output end of the second amplifier U2 and grounded. Through the frequency response characteristics of the RC network, functions such as frequency compensation, filtering, and load isolation are achieved. The core principle is to utilize the phase lag effect of the RC network to adjust the frequency response of the operational amplifier and ensure the stability of the system in the closed-loop state.

[0056] In this embodiment, the first capacitor C1, the second capacitor C2, the third capacitor C3, the fourth capacitor C4, the fifth capacitor C5, the sixth capacitor C6, and the seventh capacitor C7 are used as filtering compensation components to process the eddy current signal into a stable and clean electrical signal.

[0057] After the stable and clean electrical signal is transmitted to the magnetic levitation motor controller, accurate control signals can be output to adjust the suspension position of the rotor to the optimal state, thereby ensuring the stable and reliable operation of the magnetic levitation motor 3, avoiding problems such as motor damage caused by unstable motor operation, and even production shutdown and personal casualties, and avoiding major economic property losses.

[0058] Although the embodiments of the present invention have been shown and described, those skilled in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A magnetic levitation motor rotor displacement detection system, characterized in that: The invention comprises an eddy current sensor (1), a displacement signal processing circuit (4) and a magnetic suspension motor controller (2); the eddy current sensor (1) is installed in the magnetic suspension motor (3); the displacement signal processing circuit (4) comprises a primary signal amplification circuit (41) and a secondary signal amplification circuit (42); the input end of the primary signal amplification circuit (41) is connected to the signal output end of the eddy current sensor (1); the output end of the primary signal amplification circuit (41) is connected to the input end of the secondary signal amplification circuit (42); the output end of the secondary signal amplification circuit (42) is connected to the input end of the magnetic suspension motor controller (2); and the output end of the magnetic suspension motor controller (2) is connected to the magnetic suspension motor (3).

2. A magnetic levitation motor rotor displacement detection system according to claim 1, characterized in that: The first-stage signal amplification circuit (41) comprises a first amplifier U1, wherein the second pin of the first amplifier U1 is connected to a negative power supply input via a first resistor R1, and is connected to a first pin of the first amplifier U1 via a second resistor R2, and the third pin of the first amplifier U1 is connected to a positive power supply input via a third resistor R3, and is grounded via a fourth resistor R4.

3. A magnetic levitation motor rotor displacement detection system according to claim 2, characterized in that: The secondary signal amplification circuit (42) comprises a second amplifier U2 and a potentiometer RP, wherein the sixth pin of the second amplifier U2 is connected to the output end of the primary signal amplification circuit (41) via a fifth resistor R5, and is connected to the output end of the secondary signal amplification circuit (42) via a sixth resistor R6, the fifth pin of the second amplifier U2 is connected to the sliding end of the potentiometer RP via a ninth resistor R9, the first fixed end of the potentiometer RP is connected to a +10V DC voltage via a seventh resistor R7, the second fixed end of the potentiometer RP is connected to a -10V DC voltage via an eighth resistor R8, and the seventh pin of the second amplifier U2 is connected to the output end of the secondary signal amplification circuit (42) via a tenth resistor R10.

4. A magnetic levitation motor rotor displacement detection system according to claim 2, characterized in that: The first-level signal amplification circuit (41) further comprises a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4 and a fifth capacitor C5, wherein the first capacitor C1 is arranged in parallel with the first resistor R1, the second pin of the first amplifier U1 is grounded via the first capacitor C1, the second capacitor C2 is arranged in parallel with the second resistor R2, the second pin of the first amplifier U1 is connected to the first pin of the first amplifier U1 via the second capacitor C2, the third pin of the first amplifier U1 is grounded via the third capacitor C3 and the fourth resistor arranged in parallel, the fourth pin of the first amplifier U1 is connected to a +15V DC voltage and is grounded via the fourth capacitor C4, and the eleventh pin of the first amplifier U1 is connected to a -15V DC voltage and is grounded via the fifth capacitor C5.

5. The magnetic levitation motor rotor displacement detection system according to claim 3, characterized in that: The secondary signal amplification circuit (42) further comprises a sixth capacitor C6 and a seventh capacitor C7, the sixth capacitor C6 and the sixth resistor R6 are arranged in parallel, the sixth pin of the second amplifier U2 is connected to the output end of the secondary signal amplification circuit (42) via the sixth capacitor C6, the seventh capacitor C7 and the tenth resistor R10 are arranged in series, and the seventh pin of the second amplifier U2 is grounded via the tenth resistor R10 and the seventh capacitor C7.

6. A magnetic levitation motor rotor displacement detection system according to claim 2, characterized in that: The resistance values ​​of the first resistor R1 , the second resistor R2 , the third resistor R3 and the fourth resistor R4 are all the same.

7. The magnetic levitation motor rotor displacement detection system according to claim 3, characterized in that: The resistance values ​​of the fifth resistor R5, the sixth resistor R6, the seventh resistor R7, the eighth resistor R8 and the potentiometer RP are all the same.

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