CN209687938U - Displacement correction device and magnetic suspension bearing system - Google Patents
Displacement correction device and magnetic suspension bearing system Download PDFInfo
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- CN209687938U CN209687938U CN201920252927.2U CN201920252927U CN209687938U CN 209687938 U CN209687938 U CN 209687938U CN 201920252927 U CN201920252927 U CN 201920252927U CN 209687938 U CN209687938 U CN 209687938U
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- 238000006073 displacement reaction Methods 0.000 title claims abstract description 125
- 238000012937 correction Methods 0.000 title claims abstract description 101
- 239000000725 suspension Substances 0.000 title claims abstract description 34
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Abstract
The utility model discloses a displacement correcting unit and magnetic suspension bearing system, the device includes: a reference circuit and a correction circuit; the reference circuit is used for providing a reference signal; and the correction circuit is used for carrying out logarithmic operation on the nonlinear displacement signal to be corrected based on the reference signal to obtain a corrected linear displacement signal. The utility model discloses a scheme, the position detection signal that can solve the output of eddy current sensor and the displacement signal of axle are not linear relation and lead to detecting the poor problem of accuracy, reach the effect that promotes the detection accuracy.
Description
Technical Field
The utility model belongs to the technical field of the magnetic suspension, concretely relates to displacement correcting unit and magnetic suspension bearing system especially relate to a linear correction circuit of eddy current displacement sensor and have this linear correction circuit's magnetic suspension bearing system.
Background
In a magnetic suspension bearing system, a precise position sensor is required to detect the position of a shaft in real time in order to achieve stable suspension of the shaft. According to the requirement of a magnetic suspension system, the linearity and the resolution of the position sensor are required to be higher. A common sensor is an eddy current displacement sensor.
The eddy current sensor has high resolution but insufficient linear range. In a magnetic bearing system, the axial position detection of the shaft requires a large sensor range. When the requirement of the measuring range is met, the position signal output of the eddy current sensor is obviously nonlinear; that is, the signal output by the sensor and the displacement signal are not in a linear relationship, which leads to inaccurate detection position, unstable suspension, poor suspension precision, even shaft collision and damage to the magnetic suspension system.
The above is only for the purpose of assisting understanding of the technical solutions of the present invention, and does not represent an admission that the above is the prior art.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to the above-mentioned defect, provide a displacement correcting unit and magnetic suspension bearing system to the position detected signal who solves the output of eddy current sensor is not linear relation with the displacement signal of axle and leads to detecting the poor problem of accuracy, reaches the effect that promotes the detection accuracy.
The utility model provides a displacement correcting unit, include: a reference circuit and a correction circuit; the reference circuit is used for providing a reference signal; and the correction circuit is used for carrying out logarithmic operation on the nonlinear displacement signal to be corrected based on the reference signal to obtain a corrected linear displacement signal.
Optionally, the method further comprises: a controller; the controller is used for determining whether the linear displacement signal meets a set threshold value; if the linear displacement signal does not meet the set threshold, outputting an adjusting signal to the reference circuit; and the reference circuit is used for adjusting the reference signal based on the adjusting signal so as to obtain the adjusted reference signal.
Optionally, the method further comprises: an analog-to-digital converter; and the analog-to-digital converter is used for performing analog-to-digital conversion on the linear displacement signal and then outputting the linear displacement signal to the controller.
Optionally, the reference circuit includes: the circuit comprises a regulating resistor, a first current limiting resistor and a comparator; the adjusting end of the adjusting resistor is used as the input end of an adjusting signal, and the adjusting resistor is connected to the non-inverting input end of the comparator; the first current limiting resistor is also connected to the non-inverting input terminal of the comparator, the inverting input terminal of the comparator is connected to the output terminal of the comparator, and the output terminal of the comparator is connected to the reference signal input terminal of the correction circuit.
Optionally, the correction circuit includes: the second current-limiting resistor, the third current-limiting resistor and the logarithmic operation circuit; the second current limiting resistor is connected between a reference signal output end of the reference circuit and a reference signal input end of the logarithmic operation circuit; and the second current limiting resistor is connected between the nonlinear displacement signal output end to be corrected and the signal input end to be corrected of the logarithmic operation circuit.
Optionally, the logarithmic operation circuit includes: an operational amplifier and a triode; the operational amplifier and the triode are built to form a logarithmic circuit; or, the logarithm operation circuit adopts a logarithm operation chip.
Optionally, the nonlinear displacement signal to be corrected comprises: detecting the axial displacement of the magnetic suspension bearing by using an eddy current sensor; wherein, in the case of matching the reference signal to the eddy current sensor: a non-linear displacement signal to be corrected, comprising: a minimum value of the axial displacement output by the eddy current sensor; the initial value of the reference signal comprises: a set minimum reference signal.
With the above device phase-match, the utility model discloses another aspect provides a magnetic suspension bearing system, include: the displacement correction device described above.
The utility model discloses a scheme, through the linear correction circuit of eddy current displacement sensor, can be effectively with the nonlinear displacement signal correction of eddy current sensor output for linear signal, can promote the accuracy to bearing displacement detection.
Further, the utility model discloses a scheme is through utilizing logarithm arithmetic circuit, according to the logarithm circuit output voltage automatic adjustment reference voltage who gathers, makes correction circuit be suitable for different sensor output, need not to change the hardware circuit, has effectively increased the circuit suitability, can also promote the stability and the reliability of magnetic suspension.
Furthermore, the scheme of the utility model, through the nonlinear signal that will have the current vortex sensor output, through the circuit correction based on logarithm operation to linear signal; meanwhile, the reference voltage is automatically adjusted through software control to match different linear correction output requirements, the output signal range is adjustable, the application range is wide, and the reliability is high.
Therefore, the utility model discloses a scheme is through the nonlinear displacement signal correction with the current vortex sensor output for linear signal, and the position detection signal who solves the current vortex sensor output is not linear relation with the displacement signal of axle and leads to detecting the poor problem of accuracy to, overcome among the prior art position detection accuracy poor, influence the defect of suspension stability and precision, realize that the position detection accuracy is good, can promote the beneficial effect of suspension stability and precision.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of the invention.
The technical solution of the present invention is further described in detail by the accompanying drawings and examples.
Drawings
Fig. 1 is a schematic structural diagram of an embodiment of the displacement calibration device of the present invention;
fig. 2 is a schematic diagram of an axial sensor detection of an embodiment of the magnetic bearing system of the present invention;
fig. 3 is a graph illustrating the signal correction effect of the eddy current sensor according to an embodiment of the magnetic suspension bearing system of the present invention;
fig. 4 is a schematic diagram of a displacement correction circuit according to an embodiment of the magnetic suspension bearing system of the present invention;
FIG. 5 is a schematic diagram of a sensor matching process for an embodiment of a magnetic bearing system;
fig. 6 is a schematic flow chart of an embodiment of the displacement calibration method of the present invention;
fig. 7 is a schematic flow chart illustrating an embodiment of matching the reference signal in the method of the present invention.
With reference to the accompanying drawings, the embodiments of the present invention have the following reference numerals:
10-axis; 20-electric eddy current sensor.
Detailed Description
To make the purpose, technical solution and advantages of the present invention clearer, the following will combine the embodiments of the present invention and the corresponding drawings to clearly and completely describe the technical solution of the present invention. It is to be understood that the embodiments described are only some embodiments of the invention, and not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.
According to the utility model discloses an embodiment provides a displacement correcting unit. Referring to fig. 1, a schematic structural diagram of an embodiment of the apparatus of the present invention is shown. The displacement correction device may include: a reference circuit and a correction circuit.
Specifically, the reference circuit may be configured to provide a reference signal and output the reference signal to a first input terminal of the correction circuit.
For example: as shown in fig. 4, an adjustable reference circuit is added to adjust the reference signal, and the adjustment circuit can automatically adjust the reference signal so as to adapt to the correction of different sensors (each sensor is definitely different).
In an alternative example, the reference circuit may include: the circuit comprises a regulating resistor, a first current limiting resistor and a comparator. As shown in fig. 4, the adjustable reference circuit may include: and the resistor, the operational amplifier and other devices are used for outputting adjustable reference voltage signals.
Specifically, the adjusting end of the adjusting resistor is used as the input end of the adjusting signal, and the adjusting resistor is connected to the non-inverting input end of the comparator. For example: the adjusting end of the adjusting resistor is connected to the adjusting signal output end of the controller, the first connecting end of the adjusting resistor is grounded, and the second connecting end of the adjusting resistor is connected to the non-inverting input end of the comparator.
Specifically, the first current limiting resistor is also connected to a non-inverting input terminal of the comparator, an inverting input terminal of the comparator is connected to an output terminal of the comparator, and an output terminal of the comparator is connected to a reference signal input terminal of the correction circuit.
Therefore, the reference circuit is formed by the adjusting resistor, the first current limiting resistor and the comparator, the structure is simple, the reference signal is adjustable, and the use flexibility is good.
Specifically, the correction circuit may be configured to perform a logarithmic operation on a to-be-corrected nonlinear displacement signal based on the reference signal to obtain a corrected linear displacement signal.
For example: the linear correction circuit of the electric eddy current displacement sensor can effectively correct the nonlinear displacement signal output by the electric eddy current sensor into a linear signal.
For example: the logarithmic operation circuit and the characteristics thereof can be utilized, the reference voltage can be automatically adjusted according to the acquired output voltage of the logarithmic circuit, the correction circuit is suitable for different sensor outputs, a hardware circuit does not need to be changed, and the circuit applicability is effectively increased.
For example: the nonlinear signal output by the conventional eddy current sensor is corrected to a linear signal by a circuit based on logarithmic operation. The signal relationship before and after the logarithmic operation circuit processing is a logarithmic relationship, that is, y is log (x/a), y is a circuit output signal, x is a circuit input signal, and a is a reference signal.
Therefore, the reference circuit provides a reference signal, the correction circuit performs logarithm operation on the nonlinear displacement signal to be corrected based on the reference signal to obtain a corrected linear displacement signal, linear correction of the nonlinear displacement signal is achieved, the structure is simple, correction accuracy is good, and reliability is high.
In an alternative example, the correction circuit may include: the current limiting circuit comprises a second current limiting resistor, a third current limiting resistor and a logarithmic operation circuit.
Specifically, the second current limiting resistor is connected between a reference signal output end of the reference circuit and a reference signal input end of the logarithmic operation circuit.
Specifically, the second current limiting resistor is connected between the nonlinear displacement signal output end to be corrected and the signal input end to be corrected of the logarithmic operation circuit.
For example: the curve characteristic of the nonlinear signal of the sensor is similar to an exponential function, and the signal is subjected to logarithmic operation, so that linear conversion is realized. The logarithmic operation circuit (or integrated logarithmic operation circuit) generally comprises two input current signals I1, I2, I1 is a reference signal, and I2 is a nonlinear signal to be corrected. The input and output relationship is as follows: u shapeo＝A·log(I2/I1) Wherein A is a fixed constant. The circuit has a certain limit to the magnitude of the input current signal. Therefore, the input signals I1 and I2 must be processed and matched to realize the signal correction. Wherein, the correction of the signal can be realized only by processing and matching the input signals I1 and I2, which comprises the following steps: according to ohm's law, the size matching of I1 is adjusted through Uref and a resistor R1, and the size of I2 is adjusted according to Ui by selecting R2.
For example: because the input is a current signal, the voltage can be converted into the current signal through a series resistor or other conversion modes according to the characteristics of a logarithmic operation circuit (or an integrated circuit). The functions of the logarithmic operation circuit, the series resistance mode and other conversion modes are to convert a voltage signal into a current signal. The series resistance mode is based on the fact that the input of the logarithmic operation circuit is also an operational amplifier, and the series resistance can convert voltage into a current signal according to the characteristics of 'virtual short' and 'virtual break' of the operational amplifier. Such as: the string resistance method may include: after the voltage signal is connected with the resistor in series, the tail end of the resistor is connected with the input of the operational amplifier, the inverting terminal of the amplifier is grounded, and the voltage signal corresponds to a current signal i which is equal to U/R according to the virtual short virtual break.
Therefore, the correction circuit is formed by the second current-limiting resistor, the third current-limiting resistor and the logarithm operation circuit, and the correction circuit is simple in structure, reliable and safe.
Optionally, the logarithmic operation circuit may include: the operational amplifier and the triode are built to form a logarithmic circuit; or, the logarithm operation circuit adopts a logarithm operation chip.
For example: as shown in fig. 4, the logarithmic operation circuit may be an integrated circuit or a self-built circuit, and performs logarithmic function operation on the signal. The logarithmic operation circuit may be a circuit or an integrated circuit that can perform logarithmic processing on the signal. For example: and a logarithmic circuit built by an operational amplifier and a triode is adopted, or a logarithmic operation chip of a chip manufacturer such as an ADL5303 chip is adopted.
Therefore, logarithmic operation is realized through logarithmic operation circuits in various forms, and the flexibility and convenience of logarithmic operation can be improved.
Optionally, the nonlinear displacement signal to be corrected may include: the resulting axial displacement of the magnetic bearing (e.g., shaft 10 shown in fig. 2) is detected by an eddy current sensor (e.g., eddy current sensor 20 shown in fig. 2).
For example: the output of the sensor is corrected into a linear signal by using the linear correction circuit of the eddy current displacement sensor, so that the linear range is improved, and the detection accuracy of the position signal is improved; the circuit can meet the correction requirements of different sensor measuring ranges, and hardware circuits are prevented from being changed. As shown in fig. 4, the non-linear signal Ui of the eddy current sensor is input to the correction circuit, and the final output Uo is a linear signal as shown by a solid line in fig. 3. Therefore, the linear range of the eddy current sensor of the magnetic suspension bearing system is increased, the reliability of the system is improved, and the circuit applicability is wide.
Therefore, the nonlinear displacement signals detected by the eddy current sensor are corrected, accurate detection of bearing displacement in a magnetic suspension bearing system can be achieved, and suspension reliability and accuracy are improved.
Wherein, in the case of matching the reference signal to the eddy current sensor: the nonlinear displacement signal to be corrected may include: a minimum value of the axial displacement output by the eddy current sensor. The initial value of the reference signal may include: a set minimum reference signal.
For example: the reference voltage is automatically adjusted by software control to match different linear correction output requirements, and the output signal range is adjustable.
Therefore, the minimum value of the axial displacement output by the eddy current sensor is preliminarily corrected based on the set minimum reference signal, so that the reference signal of the eddy current sensor is matched reliably and safely.
In an alternative embodiment, the method may further include: and a controller.
In particular, the controller, which may be disposed between the correction circuit and the reference circuit, may be configured to determine whether the linear displacement signal satisfies a set threshold. And if the linear displacement signal does not meet the set threshold, outputting an adjusting signal to the reference circuit. In a specific use process, the controller may be further configured to, in an operation of determining whether the linear displacement signal satisfies a set threshold, complete a matching setting of a measurement subject of the nonlinear displacement signal to be corrected, such as an eddy current sensor, if the linear displacement satisfies the set threshold.
Specifically, the reference circuit may be configured to adjust the reference signal based on the adjustment signal to obtain an adjusted reference signal. Furthermore, the correction circuit may be configured to perform a logarithm operation on the nonlinear displacement signal to be corrected again based on the adjusted reference signal to obtain a linear displacement signal after being corrected again.
For example: correcting a nonlinear signal output by the eddy current sensor into a linear signal through a circuit based on logarithm operation; meanwhile, the reference voltage is automatically adjusted through software control to match different linear correction output requirements, the output signal range is adjustable, the circuit can meet the correction requirements of different sensor ranges, the hardware circuit is prevented from being changed, and the circuit applicability is improved.
Therefore, the reference circuit is controlled to adjust the reference signal under the condition that the linear displacement signal output by the correction circuit is determined not to meet the set threshold value, and then the nonlinear displacement signal to be corrected is corrected again based on the adjusted reference signal, so that the reference signal of the eddy current sensor is matched, and the matching accuracy and reliability are improved.
In an alternative embodiment, the method may further include: an analog-to-digital converter.
Specifically, the analog-to-digital converter may be disposed between the correction circuit and the controller, and may be configured to perform analog-to-digital conversion on the linear displacement signal and output the linear displacement signal to the controller, so that the controller determines whether the linear displacement signal after analog-to-digital conversion meets a set threshold.
For example: as shown in fig. 4, the ADC is an analog-to-digital converter, and collects the final output signal Uo.
Therefore, the accuracy and convenience of judgment can be improved by performing analog-to-digital conversion on the corrected linear displacement signal and then determining whether the linear displacement signal subjected to the analog-to-digital conversion meets the set threshold.
Through a large amount of tests verification, adopt the technical scheme of the utility model, through the linear correction circuit of eddy current displacement sensor, can be effectively with the nonlinear displacement signal correction of eddy current sensor output for linear signal, can promote the accuracy to bearing displacement detection.
According to the utility model discloses an embodiment still provides a magnetic suspension bearing system corresponding to displacement correcting unit. The magnetic bearing system may include: the displacement correction device described above.
In an optional implementation manner, the present invention provides a linear correction circuit for an eddy current displacement sensor, which can be applied to a magnetic suspension bearing system of a variable frequency centrifugal chiller.
Optionally, the utility model discloses an in the scheme, the linear correction circuit of eddy current displacement sensor can be effectively with the nonlinear displacement signal correction of eddy current sensor output to linear signal.
Specifically, the logarithmic operation circuit and the characteristics thereof can be utilized, the reference voltage can be automatically adjusted according to the acquired output voltage of the logarithmic circuit, so that the correction circuit is suitable for different sensor outputs, a hardware circuit does not need to be changed, and the circuit applicability is effectively increased.
The signal relationship before and after the processing by the logarithm arithmetic circuit is a logarithm relationship, that is, y is log (x/a), y is a circuit output signal, x is a circuit input signal, and a is a reference signal. The input-output relationship of the signal is a logarithmic curve, which is similar to the decay curve of the sensor signal.
In an optional example, the scheme of the utility model corrects the non-linear signal output by the existing eddy current sensor into a linear signal through a circuit based on logarithm operation; meanwhile, the reference voltage is automatically adjusted through software control to match different linear correction output requirements, and the output signal range is adjustable.
That is, the present invention provides a linear correction circuit for an eddy current sensor, which corrects a non-linear signal output from the eddy current sensor into a linear signal by a circuit based on logarithmic operation; meanwhile, the reference voltage is automatically adjusted through software control to match different linear correction output requirements, the output signal range is adjustable, the circuit can meet the correction requirements of different sensor ranges, the hardware circuit is prevented from being changed, and the circuit applicability is improved.
Therefore, the utility model discloses a scheme utilizes the linear correction circuit of eddy current displacement sensor, rectifies the sensor output into linear signal, has improved linear range, has improved position signal detection accuracy; the circuit can meet the correction requirements of different sensor measuring ranges, and hardware circuits are prevented from being changed. Therefore, the linear range of the eddy current sensor of the magnetic suspension bearing system is increased, the reliability of the system is improved, and the circuit applicability is wide.
In an alternative embodiment, a specific implementation process of the scheme of the present invention can be exemplarily described with reference to the examples shown in fig. 2 to 5. In a magnetic bearing system, the shaft moves axially as shown in fig. 2, and the axially movable distance is n, i.e. n is the distance the shaft moves, so the minimum effective range required by the eddy current sensor is n. The accuracy of the eddy current sensor is high, but the linear range is small. For the detection distance n of the magnetic suspension bearing system, the change rate of the output signal of the sensor is obviously reduced along with the increase of the distance. As shown in fig. 3, the dashed line represents the output signal of the eddy current sensor, that is, the dashed line represents the output signal of the eddy current sensor before correction, and the solid line represents the output signal of the eddy current sensor after correction.
In an alternative embodiment, the calibration circuit of the present invention may be as shown in fig. 4. In fig. 4, the correction circuit may include: the device comprises an adjustable reference circuit, a logarithmic operation circuit and an MCU acquisition and control part. The non-linear signal Ui of the eddy current sensor is input to the correction circuit, and the final output Uo is a linear signal as shown in the solid line in fig. 3.
As for the correction circuit shown in fig. 4, there is no technology to correct the eddy current sensor signal using a logarithmic operation circuit. Except the logarithm circuit, the utility model discloses a scheme has add adjustable reference circuit for adjust reference signal, and the circuit that adjusts can adjust reference signal automatically to be applicable to the correction of different sensors (every sensor certainly has the difference).
Optionally, in fig. 4, the adjustable reference circuit may include: and the resistor, the operational amplifier and other devices are used for outputting adjustable reference voltage signals.
Alternatively, in fig. 4, the logarithmic operation circuit may be an integrated circuit or a self-built circuit, and performs logarithmic function operation on the signal. The logarithmic operation circuit may be a circuit or an integrated circuit that can perform logarithmic processing on the signal. For example: and a logarithmic circuit built by an operational amplifier and a triode is adopted, or a logarithmic operation chip of a chip manufacturer such as an ADL5303 chip is adopted.
Optionally, in fig. 4, the ADC is an analog-to-digital converter, and acquires a final output signal Uo; the MCU is a main control chip.
In an optional specific example, the scheme of the present invention, the curve characteristic of the sensor nonlinear signal is similar to an exponential function, and the signal is subjected to logarithmic operation, so as to realize linear conversion. The logarithmic operation circuit (or integrated logarithmic operation circuit) generally comprises two input current signals I1, I2, I1 is a reference signal, and I2 is a nonlinear signal to be corrected. The input and output relationship is as follows: u shapeo＝A·log（I2/I1) Wherein A is a fixed constant. The circuit has a certain limit to the magnitude of the input current signal. Therefore, the input signals I1 and I2 must be processed and matched to realize the signal correction.
Wherein, the correction of the signal can be realized only by processing and matching the input signals I1 and I2, which comprises the following steps: according to ohm's law, the size matching of I1 is adjusted through Uref and a resistor R1, and the size of I2 is adjusted according to Ui by selecting R2.
Optionally, since the input is a current signal, the voltage may also be converted into the current signal through a series resistor or other conversion methods according to the characteristics of the logarithmic operation circuit (or the integrated circuit).
Specifically, the functions of the logarithmic operation circuit, the series resistance method, and other conversion methods are to convert a voltage signal into a current signal. The series resistance mode is based on the fact that the input of the logarithmic operation circuit is also an operational amplifier, and the series resistance can convert voltage into a current signal according to the characteristics of 'virtual short' and 'virtual break' of the operational amplifier.
For example: the string resistance method may include: after the voltage signal is connected with the resistor in series, the tail end of the resistor is connected with the input of the operational amplifier, the inverting terminal of the amplifier is grounded, and the voltage signal corresponds to a current signal i which is equal to U/R according to the virtual short virtual break.
For example: other conversion modes such as a special conversion chip or a built special functional circuit.
Therefore, the scheme of the utility model, can use voltage signal as an example, the input/output relation is:for a particular eddy current displacement sensor, the range of its output signal Ui has been determined, i.e. the I2 range is determined. This requires matching the appropriate Uref for the signal to achieve the best correction and reasonable Uo output range. For example, to set the Uo minimum output to around 0, the value of Uref is adjusted so that I1 ≈ I2 minimum value, and the Uo output minimum value is about Alog1 ═ 0.
In the above, the correction of the nonlinear signal of the sensor and the adjustment of the output signal range have been realized. However, for different bearing systems, the axial detection distance of the sensor is different, and the output voltage range of different eddy current sensors is also different, so that the signal range to be corrected is different. To ensure the linearity correction effect and the range of the corrected signal Uo, it is necessary to adjust Uref according to different signals to be corrected. Therefore the utility model relates to a sampling that has increased the UO reads and Uref software control part. As shown in fig. 5, the sensor signal Ui is first set to the minimum value, the MCU controls the given initial Uref value (e.g., 1V), and then the MCU reads the value of Uo through the ADC signal acquisition, determines whether Uo output meets the requirement, and if not, controls the adjustable reference circuit to adjust Uref according to the required Uo output range until the desired Uo is obtained, thereby implementing automatic sensor matching using software, avoiding changing hardware circuits, and improving the applicability of the correction circuit.
In an alternative embodiment, the reference circuit is preferably an adjustable reference circuit, and may be any type of existing controllable output reference circuit, and the reference circuit output may be a voltage signal or a current signal.
For example: the utility model discloses an in the scheme, use resistance partial pressure, the circuit that follows is put to fortune as an example. Other forms of controllable output circuits such as programmable signal output chips, DAC converters, adjustable resistance voltage regulation circuits, etc.
In an alternative specific example, in the solution of the present invention, the signal to be corrected of the linear correction circuit is not limited to a voltage signal, but is also applicable to a current signal; the conversion of the voltage signal may be any form of voltage-to-current conversion circuit known in the art.
For example: other conversion modes are special voltage-current signal conversion chips or special functional circuits.
Since the processes and functions of the magnetic suspension bearing system of this embodiment are basically corresponding to the embodiments, principles and examples of the apparatus shown in fig. 1, the descriptions of this embodiment are not detailed herein, and refer to the related descriptions in the foregoing embodiments, which are not described herein again.
Through a large amount of experimental verifications, adopt the technical scheme of the utility model, through utilizing the logarithm arithmetic circuit, according to the logarithm circuit output voltage automatic adjustment reference voltage who gathers, make correction circuit be suitable for different sensor output, need not to change the hardware circuit, effectively increased the circuit suitability, can also promote the stability and the reliability of magnetic suspension.
According to an embodiment of the present invention, there is further provided a method for correcting displacement of a magnetic bearing system corresponding to the magnetic bearing system, as shown in fig. 6, the method according to an embodiment of the present invention is schematically illustrated in the flow chart. The displacement correction method of the magnetic bearing system can comprise the following steps: step S110 and step S120.
At step S110, a reference signal is provided and output to a first input of a correction circuit.
For example: as shown in fig. 4, an adjustable reference circuit is added to adjust the reference signal, and the adjustment circuit can automatically adjust the reference signal so as to adapt to the correction of different sensors (each sensor is definitely different).
In step S120, a logarithm operation is performed on the nonlinear displacement signal to be corrected based on the reference signal, so as to obtain a corrected linear displacement signal.
For example: the linear correction circuit of the electric eddy current displacement sensor can effectively correct the nonlinear displacement signal output by the electric eddy current sensor into a linear signal.
For example: the logarithmic operation circuit and the characteristics thereof can be utilized, the reference voltage can be automatically adjusted according to the acquired output voltage of the logarithmic circuit, the correction circuit is suitable for different sensor outputs, a hardware circuit does not need to be changed, and the circuit applicability is effectively increased.
For example: the nonlinear signal output by the conventional eddy current sensor is corrected to a linear signal by a circuit based on logarithmic operation. The signal relationship before and after the logarithmic operation circuit processing is a logarithmic relationship, that is, y is log (x/a), y is a circuit output signal, x is a circuit input signal, and a is a reference signal.
Therefore, the reference circuit provides a reference signal, the correction circuit performs logarithm operation on the nonlinear displacement signal to be corrected based on the reference signal to obtain a corrected linear displacement signal, linear correction of the nonlinear displacement signal is achieved, the structure is simple, correction accuracy is good, and reliability is high.
Optionally, the nonlinear displacement signal to be corrected may include: the resulting axial displacement of the magnetic bearing (e.g., shaft 10 shown in fig. 2) is detected by an eddy current sensor (e.g., eddy current sensor 20 shown in fig. 2).
For example: the output of the sensor is corrected into a linear signal by using the linear correction circuit of the eddy current displacement sensor, so that the linear range is improved, and the detection accuracy of the position signal is improved; the circuit can meet the correction requirements of different sensor measuring ranges, and hardware circuits are prevented from being changed. As shown in fig. 4, the non-linear signal Ui of the eddy current sensor is input to the correction circuit, and the final output Uo is a linear signal as shown by a solid line in fig. 3. Therefore, the linear range of the eddy current sensor of the magnetic suspension bearing system is increased, the reliability of the system is improved, and the circuit applicability is wide.
Therefore, the nonlinear displacement signals detected by the eddy current sensor are corrected, accurate detection of bearing displacement in a magnetic suspension bearing system can be achieved, and suspension reliability and accuracy are improved.
Wherein, in the case of matching the reference signal to the eddy current sensor: the nonlinear displacement signal to be corrected may include: a minimum value of the axial displacement output by the eddy current sensor. The initial value of the reference signal may include: a set minimum reference signal.
For example: the reference voltage is automatically adjusted by software control to match different linear correction output requirements, and the output signal range is adjustable.
Therefore, the minimum value of the axial displacement output by the eddy current sensor is preliminarily corrected based on the set minimum reference signal, so that the reference signal of the eddy current sensor is matched reliably and safely.
In an alternative embodiment, the method may further include: and (5) matching the reference signal.
Referring to fig. 7, a flow chart of an embodiment of the method for matching a reference signal according to the present invention is further illustrated, and the specific process of matching the reference signal may include: step S210 and step S220.
Step S210, determining whether the linear displacement signal satisfies a set threshold. And if the linear displacement signal does not meet the set threshold, outputting an adjusting signal to the reference circuit. In a specific use process, the controller may be further configured to, in an operation of determining whether the linear displacement signal satisfies a set threshold, complete a matching setting of a measurement subject of the nonlinear displacement signal to be corrected, such as an eddy current sensor, if the linear displacement satisfies the set threshold.
Step S220, adjusting the reference signal based on the adjustment signal to obtain an adjusted reference signal. Furthermore, the correction circuit may be configured to perform a logarithm operation on the nonlinear displacement signal to be corrected again based on the adjusted reference signal to obtain a linear displacement signal after being corrected again.
For example: correcting a nonlinear signal output by the eddy current sensor into a linear signal through a circuit based on logarithm operation; meanwhile, the reference voltage is automatically adjusted through software control to match different linear correction output requirements, the output signal range is adjustable, the circuit can meet the correction requirements of different sensor ranges, the hardware circuit is prevented from being changed, and the circuit applicability is improved.
Therefore, the reference circuit is controlled to adjust the reference signal under the condition that the linear displacement signal output by the correction circuit is determined not to meet the set threshold value, and then the nonlinear displacement signal to be corrected is corrected again based on the adjusted reference signal, so that the reference signal of the eddy current sensor is matched, and the matching accuracy and reliability are improved.
In an alternative embodiment, the method may further include: and after analog-to-digital conversion is carried out on the linear displacement signal, the linear displacement signal is output to the controller, so that the controller determines whether the linear displacement signal after analog-to-digital conversion meets a set threshold value.
For example: as shown in fig. 4, the ADC is an analog-to-digital converter, and collects the final output signal Uo.
Therefore, the accuracy and convenience of judgment can be improved by performing analog-to-digital conversion on the corrected linear displacement signal and then determining whether the linear displacement signal subjected to the analog-to-digital conversion meets the set threshold.
Since the processing and functions implemented by the method of this embodiment substantially correspond to the embodiments, principles and examples of the magnetic suspension bearing system shown in fig. 2 to fig. 5, the description of this embodiment is not detailed, and reference may be made to the related description in the foregoing embodiments, which is not repeated herein.
Through a large number of tests, the technical scheme of the embodiment is adopted, and the nonlinear signal output by the existing eddy current sensor is corrected into a linear signal through a circuit based on logarithm operation; meanwhile, the reference voltage is automatically adjusted through software control to match different linear correction output requirements, the output signal range is adjustable, the application range is wide, and the reliability is high.
In summary, it is readily understood by those skilled in the art that the advantageous modes described above can be freely combined and superimposed without conflict.
The above description is only an example of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.
Claims (8)
1. A displacement correction device, characterized by comprising: a reference circuit and a correction circuit; wherein,
the reference circuit is used for providing a reference signal;
and the correction circuit is used for carrying out logarithmic operation on the nonlinear displacement signal to be corrected based on the reference signal to obtain a corrected linear displacement signal.
2. The displacement correction device according to claim 1, characterized by further comprising: a controller;
the controller is used for determining whether the linear displacement signal meets a set threshold value; if the linear displacement signal does not meet the set threshold, outputting an adjusting signal to the reference circuit;
and the reference circuit is used for adjusting the reference signal based on the adjusting signal so as to obtain the adjusted reference signal.
3. The displacement correction device according to claim 2, characterized by further comprising: an analog-to-digital converter;
and the analog-to-digital converter is used for performing analog-to-digital conversion on the linear displacement signal and then outputting the linear displacement signal to the controller.
4. The displacement correction device according to one of claims 1 to 3, wherein the reference circuit includes: the circuit comprises a regulating resistor, a first current limiting resistor and a comparator; wherein,
the adjusting end of the adjusting resistor is used as the input end of an adjusting signal, and the adjusting resistor is connected to the non-inverting input end of the comparator;
the first current limiting resistor is also connected to the non-inverting input terminal of the comparator, the inverting input terminal of the comparator is connected to the output terminal of the comparator, and the output terminal of the comparator is connected to the reference signal input terminal of the correction circuit.
5. The displacement correction device according to one of claims 1 to 3, characterized in that the correction circuit comprises: the second current-limiting resistor, the third current-limiting resistor and the logarithmic operation circuit; wherein,
the second current limiting resistor is connected between the reference signal output end of the reference circuit and the reference signal input end of the logarithmic operation circuit;
and the second current limiting resistor is connected between the nonlinear displacement signal output end to be corrected and the signal input end to be corrected of the logarithmic operation circuit.
6. The displacement correction device according to claim 5, wherein the logarithmic operation circuit includes: an operational amplifier and a triode; the operational amplifier and the triode are built to form a logarithmic circuit;
or,
the logarithm operation circuit adopts a logarithm operation chip.
7. A displacement correction device according to one of claims 1 to 3, characterized in that the non-linear displacement signal to be corrected comprises: detecting the axial displacement of the magnetic suspension bearing by using an eddy current sensor;
wherein,
in the case of matching the reference signal to the eddy current sensor:
a non-linear displacement signal to be corrected, comprising: a minimum value of the axial displacement output by the eddy current sensor;
the initial value of the reference signal comprises: a set minimum reference signal.
8. A magnetic bearing system, comprising: the displacement correction device according to any one of claims 1 to 7.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201920252927.2U CN209687938U (en) | 2019-02-27 | 2019-02-27 | Displacement correction device and magnetic suspension bearing system |
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| CN201920252927.2U CN209687938U (en) | 2019-02-27 | 2019-02-27 | Displacement correction device and magnetic suspension bearing system |
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| CN209687938U true CN209687938U (en) | 2019-11-26 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109654125A (en) * | 2019-02-27 | 2019-04-19 | 珠海格力电器股份有限公司 | Displacement correction device, magnetic suspension bearing system and displacement correction method thereof |
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2019
- 2019-02-27 CN CN201920252927.2U patent/CN209687938U/en not_active Withdrawn - After Issue
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109654125A (en) * | 2019-02-27 | 2019-04-19 | 珠海格力电器股份有限公司 | Displacement correction device, magnetic suspension bearing system and displacement correction method thereof |
| CN109654125B (en) * | 2019-02-27 | 2024-02-06 | 珠海格力电器股份有限公司 | Displacement correction device, magnetic suspension bearing system and displacement correction method thereof |
| US12021460B2 (en) | 2019-02-27 | 2024-06-25 | Gree Electric Appliances, Inc. Of Zhuhai | Displacement correction apparatus, magnetic levitation bearing system and displacement correction method thereof |
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