WO2020155974A1

WO2020155974A1 - System and method for detecting lateral deviation of permanent magnet suspension

Info

Publication number: WO2020155974A1
Application number: PCT/CN2019/128862
Authority: WO
Inventors: 邓永芳; 曾金成; 杨杰; 唐宏
Original assignee: 赣州德业电子科技有限公司; 江西理工大学
Priority date: 2019-01-31
Filing date: 2019-12-26
Publication date: 2020-08-06
Also published as: CN109883319B; CN109883319A

Abstract

Disclosed is a system for detecting lateral deviation of permanent magnet suspension. The system comprises a bogie (3) arranged above a permanent magnet rail (7) and used for bearing a load to realize operation or steering; a permanent magnet array (4) fixed on a lower surface of the bogie (3) and arranged opposite a magnetic pole on the permanent magnet rail (7), wherein a magnetic pole at a lower part of the permanent magnet array (4) is the same as the magnetic pole at an upper part of the permanent magnet rail (7), so as to interact with a magnetic field of the permanent magnet rail (7) to provide upward thrust for the bogie (3) so as to maintain the bogie (3) in a suspended state without direct contact relative to the permanent magnet rail (7); an insulating support (5) arranged on a lower side of the bogie (3) and arranged opposite the magnetic pole on the permanent magnet rail (7); and a coil (6) wound on the insulating support (5) in the same direction, wherein under the action of the magnetic field between the permanent magnet array (4) and the permanent magnet rail (7), the coil (6) generates electromagnetic induction and produces an induced current; the coil (6) is further connected in series to an amplifier (1) and a current detection unit (2) to form a detection circuit, and after the induced current is amplified by the amplifier (1), the current detection unit (2) detects the magnitude and/or direction of the induced current; the magnetic flux in the coil (6) is maintained within a first magnetic flux range in the state where there is no lateral deviation between the bogie (3) and the permanent magnet rail (7), and the induced current detected in the detection circuit is correspondingly maintained within a first current range; the magnetic flux in the coil (6) exceeds the first magnetic flux range in the state where lateral deviation occurs between the bogie (3) and the permanent magnet rail (7), and correspondingly, the induced current detected in the detection circuit exceeds the first current range; and the detection system detects, according to the magnitude and/or direction of the induced current, whether lateral deviation occurs and/or the direction of the lateral deviation and/or the displacement of the lateral deviation. Disclosed is a method for detecting lateral deviation of permanent magnet suspension.

Description

Detection system and method for lateral deviation of permanent magnetic suspension

Technical field

The invention relates to the technical field of magnetic levitation rail transportation, in particular to a detection system and method for lateral deviation of permanent magnetic levitation.

Background technique

There are many types of existing transportation modes in the field of maglev rail transit, such as electromagnetic levitation trains, electric levitation trains, and permanent maglev trains. The electromagnetic levitation system maintains levitation through the interaction between the electromagnets installed on the locomotive and the ferromagnetics installed on the track. The electric levitation system uses magnets on the moving locomotive to generate current on the guide rails. The electromagnetic repulsion force will increase when the gap between the locomotive and the guide rail is reduced, and the corresponding electromagnetic repulsion force is generated, which provides stable support and guide. The permanent magnet levitation system interacts with the permanent magnet track through the permanent magnet group to keep the permanent magnet levitation system levitation running on the center line of the slot, and the electromagnetic guidance can realize zero friction operation. The first two require complex control systems and consume a lot of electrical energy during operation. Compared with the previous two magnetic levitation systems, permanent magnetic levitation used in rail transit has the advantages of energy saving, low cost manufacturing and good safety.

However, once the permanent magnet levitation system is running, it will bring a series of safety problems to the train. At present, there are few reports on the detection of lateral deviation of permanent magnetic suspension.

Summary of the invention

In view of the shortcomings of the detection technology for the lateral deviation of the permanent magnetic levitation system in the prior art, the present invention provides a system and method capable of detecting the lateral deviation of the permanent magnetic levitation system. The system and method of the present invention can effectively detect whether the permanent magnet array is deviated. And measure the deviation, realize the detection of the lateral deviation of the permanent magnetic levitation system, and provide a guarantee for the stable operation of the train.

First of all, in order to achieve the above objective, a permanent magnetic suspension lateral deviation detection system is proposed, which includes: a bogie, which is arranged above the permanent magnet track and is used to support the load for operation or steering; and a permanent magnet array, which is fixed at the station. The lower surface of the bogie is arranged opposite to the magnetic poles on the permanent magnet track; the magnetic poles at the lower part of the permanent magnet array are the same as the magnetic poles on the upper part of the permanent magnet track and are used to interact with the magnetic field of the permanent magnet track In order to provide upward thrust to the bogie, the bogie is maintained in a suspended state with no direct contact with the permanent magnet track; an insulating support is provided on the lower side of the bogie and is connected to the permanent magnet track The magnetic poles are arranged opposite to each other; the coils are wound on the insulating support in the same direction, and the coils are subjected to the action of the magnetic field between the permanent magnet array and the permanent magnet track to generate electromagnetic induction and generate induced current; The coil is also connected in series with an amplifier and a current detection unit to form a detection circuit, and the induced current is amplified by the amplifier for the current detection unit to detect the magnitude and/or direction of the induced current; the magnetic flux in the coil is The bogie and the permanent magnet track are maintained within the first magnetic flux range without lateral deviation, and the induced current detected in the detection circuit is correspondingly maintained within the first current range; The magnetic flux in the coil exceeds the first magnetic flux range in a state of lateral deviation between the bogie and the permanent magnet track, and correspondingly, the induced current detected in the detection circuit exceeds the first magnetic flux range. A current range, the detection system detects whether a lateral deviation occurs and/or the direction of the lateral deviation and/or the displacement of the lateral deviation according to the magnitude and/or direction of the induced current.

Optionally, in the above-mentioned permanent magnetic suspension lateral deviation detection system, the lower surface of the bogie is provided with two sets of the permanent magnet arrays, and the magnetic poles of each set of the lower part of the permanent magnet arrays are respectively connected to one The magnetic poles of the permanent magnet track are opposite; the insulating support is arranged between the permanent magnet array and the magnetic field of the permanent magnet track, and at least one set of the permanent magnet array and one permanent magnet track are arranged opposite to each other. One piece of the insulating support, the insulating supports are parallel to each other, the coils are respectively wound on the insulating supports, and the permanent magnet arrays and the permanent magnet tracks are arranged between the same group The coils wound on the insulating support are connected in parallel or in series to form a coil combination; the coil combination is connected in series with the amplifier and the current detection unit to form a detection circuit, which is based on the magnitude and/or direction of the induced current It is detected whether a lateral deviation and/or the direction of the lateral deviation and/or the displacement of the lateral deviation occurs.

Optionally, in the above-mentioned permanent magnetic suspension lateral deviation detection system, the long axis of the insulating support is perpendicular to the running direction of the bogie.

Optionally, in the detection system for lateral deviation of the permanent magnetic suspension described above, the current detection unit is an ammeter.

Optionally, in the above-mentioned permanent magnetic suspension lateral deviation detection system, the insulating support is symmetrically arranged at both ends of the long axis direction of the bogie.

Optionally, in the above-mentioned permanent magnetic suspension lateral deviation detection system, the cross section of the coil perpendicular to the long axis direction of the insulating support is any one or a combination of square, diamond, circular, elliptical, or triangular .

Optionally, in the above-mentioned permanent magnetic suspension lateral deviation detection system, the length of the coil is 5-2000 mm, the width is 5-1500 mm, and the number of turns is 1-2000.

Optionally, in the aforementioned system for detecting lateral deviation of permanent magnetic suspension, the coil is made of copper, aluminum or iron.

Optionally, in the aforementioned system for detecting lateral deviation of permanent magnetic suspension, the permanent magnetic array adopts a Halbach array.

Secondly, in order to achieve the above purpose, a method for detecting lateral deviation of permanent magnetic levitation is also proposed, which is used in the above-mentioned detection system of permanent magnetic levitation lateral deviation. The steps include: the first step is to shift the lateral deviation of the permanent magnet array. Calibrate the relationship with the magnitude of the induced current detected in the detection circuit; in the second step, while the bogie is running or turning along the permanent magnet track, the coil is subjected to The magnetic field between the permanent magnet array and the permanent magnet track causes electromagnetic induction to generate an induced current; the induced current is amplified by the amplifier in the detection circuit and supplied to the current detection unit in the detection circuit Detect the magnitude and/or direction of the induced current; in the third step, when the induced current detected in the detection circuit exceeds the first current range, detect the magnitude and/or direction of the induced current Whether the bogie is laterally deviated from the permanent magnet track and/or the direction of the lateral deflection and/or the displacement of the lateral deflection.

Optionally, in the method for detecting lateral deviation of the permanent magnet levitation described above, in the first step, the specific steps of calibration include: step 101, maintaining the bogie directly above the permanent magnet track, and measuring this In the running state, the magnitude and/or direction of the induced current detected by the current detection unit is marked as the first current range; step 102, to drive the bogie to the left or to the left of the permanent magnet track, respectively The right side is deviated by different displacements, and the magnitude and/or direction of the induced current detected by the current detection unit in different deviated directions and different deviated positions are measured; step 103, the deviated direction and the deviated position are respectively established with the The corresponding relationship between the magnitude and/or direction of the induced current is recorded in a table, so that the deviation direction and the deviation position are calibrated by the magnitude and/or direction of the induced current.

Beneficial effect

In the present invention, a horizontally placed coil is placed between the bogie and the permanent magnet track, that is, between the two permanent magnet arrays facing each other up and down. If the permanent magnet levitation does not deviate, the magnetic flux in the coil does not change. , Therefore, no current is generated; when the permanent magnetic levitation is side-biased with permanent magnet array bogies also deviate, as the permanent magnetic group on the bogie is side-biased, the magnetic flux through the coil changes, that is, current is generated; The displacement of the side deflection is different, the change of the magnetic flux is also different, so different amounts of side deflection will produce different current values. Therefore, the present invention can obtain the corresponding lateral deviation direction and coordinates by calculating the magnitude and direction of the induced current caused by the magnetic flux. The invention can effectively detect whether the permanent magnet array deviates and measure the deviation, and provide a guarantee for the stable operation of the train.

Other features and advantages of the present invention will be described in the following description, and partly become obvious from the description, or understood by implementing the present invention.

Description of the drawings

The accompanying drawings are used to provide a further understanding of the present invention, and constitute a part of the specification, and together with the embodiments of the present invention, are used to explain the present invention, and do not constitute a limitation to the present invention. In the attached picture:

1 is a schematic diagram of the overall structure of the detection device for lateral deviation of permanent magnetic suspension of the present invention;

In the figure, 1 represents an amplifier; 2 represents a current meter; 3 represents a bogie; 4 represents a permanent magnet array; 5 represents an insulating support; 6 represents a coil; 7 represents a permanent magnet track; 8 represents a wire.

detailed description

In order to make the purpose and technical solutions of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be described clearly and completely in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the described embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative labor are within the protection scope of the present invention.

Those skilled in the art can understand that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meanings as those commonly understood by those of ordinary skill in the art to which the present invention belongs. It should also be understood that terms such as those defined in general dictionaries should be understood as having meanings consistent with the meanings in the context of the prior art, and unless defined as here, they will not be used in ideal or overly formal meanings. Explanation.

The meaning of "and/or" in the present invention refers to the fact that each exists alone or both exist simultaneously.

The meaning of "up and down" in the present invention means that when the user looks along the running direction of the bogie, the upper side of the user is the upper side and the lower side of the user is the lower side, rather than the device of the present invention. The specific limits of the organization.

The meaning of "left and right" in the present invention means that when the user looks along the running direction of the bogie, the user's left is the left, and the user's right is the right, not for the device of the present invention. The specific limits of the organization.

The meaning of "connection" in the present invention can be a direct connection between components or an indirect connection between components through other components.

The "out of range" in the present invention means that it is not within the original range, and it is not that the specific index value is greater than the original range. "Out of range" also includes the case where the value is lower than the minimum value of the original range.

Fig. 1 is a detection system for lateral deviation of permanent magnetic levitation according to the present invention, which includes: a bogie 3, which is arranged above the permanent magnet track 7, and is used for supporting a load to realize operation or steering;

The permanent magnet array 4 is fixed on the lower surface of the bogie 3 and is arranged opposite to the magnetic poles on the permanent magnet track 7; the magnetic poles at the lower part of the permanent magnet array 4 are the same as the magnetic poles at the upper part of the permanent magnet track 7, Used to interact with the magnetic field of the permanent magnet track 7 to provide upward thrust to the bogie 3 and maintain the bogie 3 in a suspended state with no direct contact with the permanent magnet track 7;

The insulating support 5 is arranged on the lower side of the bogie 3 and is arranged opposite to the magnetic poles on the permanent magnet track 7;

The coil 6 is wound on the insulating support 5 in the same direction. The coil 6 is subjected to the action of the magnetic field between the permanent magnet array 4 and the permanent magnet track 7 to generate electromagnetic induction and generate an induced current; The coil 6 is also connected in series with the amplifier 1 and the current detection unit 2 to form a detection circuit, and the induced current is amplified by the amplifier 1 for the current detection unit 2 to detect the magnitude and/or direction of the induced current; The magnetic flux in 6 is maintained within the first magnetic flux range without lateral deviation between the bogie 3 and the permanent magnet track 7, and the induced current detected in the detection circuit is correspondingly maintained in the first magnetic flux range. Within a current range; the magnetic flux in the coil 6 exceeds the first magnetic flux range in the state of lateral deviation between the bogie 3 and the permanent magnet track 7, correspondingly, in the detection circuit When the detected induced current exceeds the first current range, the detection system detects whether a lateral deviation occurs and/or the direction of the lateral deviation and/or the direction of the lateral deviation according to the magnitude and/or direction of the induced current Displacement of lateral deviation.

It detects the lateral deviation as follows:

In the first step, the entire device needs to calibrate the relationship between the displacement of the permanent magnet array offset and the magnitude of the current before use, that is, the displacement of the permanent magnet array 4 laterally deviated from the detection circuit detected Calibration of the relationship between the magnitude of the induced current;

Wherein, the specific steps of calibration include: step 101, maintaining the bogie 3 directly above the permanent magnet track 7, and measuring the magnitude and/or the induced current detected by the current detection unit 2 in this operating state Direction, mark its range as the first current range; step 102, drive the bogie 3 to the left or right of the permanent magnet track 7 to deviate different displacements, and measure the deviations in different deviated directions and different deviated positions. The magnitude and/or direction of the induced current detected by the current detection unit 2; step 103, the deviation direction and the deviation position are respectively established corresponding to the magnitude and/or direction of the induced current, and recorded as a table , Thereby calibrating the deviation direction and the deviation position by the magnitude and/or direction of the induced current;

In the second step, while the bogie 3 is running or turning along the permanent magnet track 7, the coil 6 is affected by the magnetic field between the permanent magnet array 4 and the permanent magnet track 7. Function: electromagnetic induction occurs to generate an induced current; the induced current is amplified by the amplifier 1 in the detection circuit for the current detection unit 2 in the detection circuit to detect the magnitude and/or direction of the induced current;

In the third step, when the induced current detected in the detection circuit exceeds the first current range, it is detected whether the bogie 3 is relative to the permanent magnet track 7 according to the magnitude and/or direction of the induced current. The lateral deviation and/or the direction of the lateral deviation and/or the displacement of the lateral deviation.

In a preferred implementation mode, the permanent magnet track 7 includes two parallel to each other, and the lower surface of the bogie 3 is provided with two groups of the permanent magnet array 4 corresponding to each other. The magnetic poles at the lower part of the permanent magnet array 4 are opposite to the magnetic poles of the permanent magnet track 7; the insulating support 5 is arranged between the permanent magnet array 4 and the magnetic field of the permanent magnet track 7, that is, it is equipped with permanent magnets. The bogie of the magnetic array is arranged above the permanent magnetic array track. The permanent magnet array is under the bogie. At least one insulating support 5 is arranged between a set of the permanent magnet array 4 and a permanent magnet track 7 arranged oppositely, and the insulating supports 5 are parallel to each other, and each insulating support 5 is respectively The coil 6 is wound, and the coil is supported on a permanent magnet assembly mounted on the bogie with an insulating bracket, and the coil is supported under the permanent magnet array on the bogie with an insulating bracket. The coils 6 wound on the insulating supports 5 arranged between the same group of the permanent magnet array 4 and the permanent magnet track 7 are connected in parallel or in series to form a coil combination; the coil combination and the amplifier 1 And the current detection unit 2 is connected in series to form a detection circuit to detect whether a lateral deviation occurs and/or the direction of the lateral deviation and/or the direction of the lateral deviation according to the magnitude and/or direction of the induced current Displacement.

At this time, the long axis of the insulating support 5 is perpendicular to the running direction of the bogie 3; the current detection unit 2 can be specifically selected as a current meter; the insulating support 5 is symmetrically arranged at both ends of the long axis of the bogie 3 The cross section of the coil 6 perpendicular to the long axis direction of the insulating support 5 is any one or a combination of square, diamond, round, ellipse or triangle; the length of the coil 6 is 5-2000mm, and the width is 5-1500mm , The number of turns is 1-2000; the coil 6 is made of copper, aluminum or iron; and the permanent magnet array 4 is a Halbach array.

In one implementation.

The bogie 3 has a length of 1000 mm and a thickness of 30 mm, and a permanent magnet array 4 is installed at the bottom of both sides. The permanent magnet array 4 is a square Halbach permanent magnet array with a length of 150 mm, a width of 100 mm, and a height of 20 mm. The permanent magnet array is divided into two upper and lower parts, and the upper part is installed on the bogie 3. The coil is a square coil 6 whose material is copper. The coil 6 has a length of 150 mm, a width of 100 mm, and a height of 10 mm, and is installed under the permanent magnet array on the bogie 3 with an insulating bracket. The permanent magnet track 4 is divided into two pieces, both of which are composed of Halbach permanent magnet arrays, with a width of 300 mm and a height of 30 mm. The current amplifier 1 selects an amplifier with an amplification factor of 500 times.

When the permanent magnetic levitation of the train does not deviate, the magnetic flux passing through the coil does not change, so the measured current is 0;

When the train deviates while the train is running, the permanent magnet array 2 on the bogie will also deviate. When the deviated displacement is 10mm, the reading of the ammeter is 26mA. Thus, the present invention can know whether there is a lateral deviation between the bogie 3 and the permanent magnet track 7 and/or the direction of the lateral deviation and/or the displacement of the lateral deviation through the calibration of the induced current. , Realize the detection of lateral deviation.

The above are only the embodiments of the present invention, and the description is relatively specific and detailed, but it should not be understood as a limitation to the patent scope of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can be made, and these all fall within the protection scope of the present invention.

Claims

A detection system for lateral deviation of permanent magnetic suspension, which is characterized in that it comprises:

The bogie (3) is set above the permanent magnet track (7) and is used to support the load to realize operation or steering;

The permanent magnet array (4) is fixed on the lower surface of the bogie (3) and is arranged opposite to the magnetic poles on the permanent magnet track (7); the magnetic poles at the lower part of the permanent magnet array (4) and the permanent magnet The magnetic poles on the upper part of the magnetic track (7) are the same, which are used to interact with the magnetic field of the permanent magnetic track (7) to provide upward thrust to the bogie (3) and maintain the bogie (3) relative to the The permanent magnet track (7) is in a suspended state without direct contact;

An insulating support (5) is arranged on the lower side of the bogie (3) and is arranged opposite to the magnetic poles on the permanent magnet track (7);

The coil (6) is wound on the insulating support (5) in the same direction, and the coil (6) is affected by the magnetic field between the permanent magnet array (4) and the permanent magnet track (7) , Electromagnetic induction occurs to generate an induced current; the coil (6) is also connected in series with the amplifier (1) and the current detection unit (2) to form a detection circuit, and the induced current is amplified by the amplifier (1) for the current The detection unit (2) detects the magnitude and/or direction of the induced current; the magnetic flux in the coil (6) has no lateral deviation between the bogie (3) and the permanent magnet track (7) In the state, it is maintained within the first magnetic flux range, and the induced current detected in the detection circuit is correspondingly maintained within the first current range; the magnetic flux in the coil (6) is in the bogie (3) and When the lateral deviation between the permanent magnet tracks (7) exceeds the first magnetic flux range, correspondingly, the induced current detected in the detection circuit exceeds the first current range, and the detection system According to the magnitude and/or direction of the induced current, it is detected whether there is a lateral deviation and/or the direction of the lateral deviation and/or the displacement of the lateral deviation.
The permanent magnetic suspension lateral deviation detection system according to claim 1, characterized in that, the permanent magnetic track (7) includes two parallel to each other, and the lower surface of the bogie (3) is correspondingly provided with 2 sets of said permanent magnet arrays (4), the magnetic poles of the lower part of each set of said permanent magnet arrays (4) are respectively opposite to the magnetic poles of one said permanent magnet track (7);

The insulating support (5) is arranged between the permanent magnet array (4) and the magnetic field of the permanent magnet track (7), and a set of the permanent magnet array (4) and one permanent magnet track ( 7) At least one of the insulating supports (5) is arranged between them, the insulating supports (5) are parallel to each other, and the coils (6) are respectively wound on the insulating supports (5), The coils (6) wound on the insulating supports (5) arranged between the permanent magnet array (4) and the permanent magnet track (7) of the same group are connected in parallel or in series to form a coil combination; The coil combination is connected in series with the amplifier (1) and the current detection unit (2) to form a detection circuit to detect whether there is a lateral deviation and/or the lateral direction according to the magnitude and/or direction of the induced current The direction of deviation and/or the displacement of said lateral deviation.
The permanent magnetic suspension lateral deviation detection system according to claim 2, characterized in that the long axis of the insulating support (5) is perpendicular to the running direction of the bogie (3).
The detection system for lateral deviation of permanent magnetic suspension according to claims 1 to 3, characterized in that the current detection unit (2) is an ammeter.
The permanent magnetic suspension lateral deviation detection system according to claims 1 to 4, characterized in that the insulating support (5) is symmetrically arranged at both ends of the long axis direction of the bogie (3).
The permanent magnetic suspension lateral deviation detection system according to claims 1 to 4, characterized in that the cross section of the coil (6) perpendicular to the long axis of the insulating support (5) is square, diamond, or circular Any one or combination of, oval or triangle.
The permanent magnetic suspension lateral deviation detection system according to claims 1 to 6, characterized in that the length of the coil (6) is 5-2000mm, the width is 5-1500mm, and the number of turns is 1-2000; and /Or, the coil (6) is made of copper, aluminum or iron.
The detection system for lateral deviation of permanent magnetic suspension according to claims 1 to 6, characterized in that the permanent magnetic array (4) adopts a Halbach array.
A method for detecting lateral deviation of permanent magnetic levitation, which is characterized in that it is used in the detection system for lateral deviation of permanent magnetic levitation according to any one of claims 1 to 8, and the steps include:

The first step is to calibrate the relationship between the displacement of the permanent magnet array (4) lateral deviation and the magnitude of the induced current detected in the detection circuit;

In the second step, while the bogie (3) is running or turning along the permanent magnet track (7) supporting the load, the coil (6) is affected by the permanent magnet array (4) and the permanent magnet The action of the magnetic field between the magnetic tracks (7) causes electromagnetic induction to generate an induced current; the induced current is amplified by the amplifier (1) in the detection circuit and supplied to the current detection unit (2) in the detection circuit Detecting the magnitude and/or direction of the induced current;

In the third step, when the induced current detected in the detection circuit exceeds the first current range, whether the bogie (3) is relative to the permanent magnet track is detected according to the magnitude and/or direction of the induced current (7) The lateral deviation and/or the direction of the lateral deviation and/or the displacement of the lateral deviation occurs.
The method for detecting lateral deviation of permanent magnetic suspension according to claim 9, wherein the step of calibration in the first step comprises:

Step 101: Maintain the bogie (3) directly above the permanent magnet track (7), and measure the magnitude and/or direction of the induced current detected by the current detection unit (2) in this operating state, Mark its range as the first current range;

Step 102: Drive the bogie 3 to the left or right of the permanent magnet track (7) to deviate by different displacements respectively, and measure the current detection unit (2) in different deflection directions and different deflection positions. The magnitude and/or direction of the induced current;

Step 103: Establish the corresponding relationship between the deviation direction and the deviation position and the magnitude and/or direction of the induced current respectively, and record them as a table, thereby calibrating the magnitude and/or direction of the induced current. The deviation direction and the deviation position.