阅读说明：本技术 一种基于永磁同步直线电机及霍尔位置传感器的系统 (System based on permanent magnet synchronous linear motor and Hall position sensor ) 是由 刘吉柱 章晓旗 于 2021-09-23 设计创作，主要内容包括：本发明实施例的目的在于提供基于永磁同步直线电机及霍尔位置传感器的系统。该系统基于霍尔效应原理结合永磁同步直线电机的定子空间结构及电气模型,进行了基于线性霍尔传感器的信号发生结构设计,采用“三相六霍尔”的信号发生结构消除了三次谐波对位置传感器测量精度的影响,不仅具有高精度的优点,还具有低成本、简化平台需求的优点。(The embodiment of the invention aims to provide a system based on a permanent magnet synchronous linear motor and a Hall position sensor. The system is based on a Hall effect principle, combines a stator space structure and an electric model of a permanent magnet synchronous linear motor, performs signal generation structural design based on a linear Hall sensor, adopts a three-phase six-Hall signal generation structure to eliminate the influence of third harmonic on the measurement precision of a position sensor, and has the advantages of high precision, low cost and simplified platform requirement.)

1. A system based on a permanent magnet synchronous linear motor and a Hall position sensor is characterized in that,

the permanent magnet synchronous linear motor includes: a mover and a stator;

the stator comprises a permanent magnet, the permanent magnet comprises a plurality of permanent magnet N poles and permanent magnet S poles, and the permanent magnet N poles and the permanent magnet S poles are arranged at intervals and at equal intervals to form a fixed array;

the Hall position sensor is arranged on the end face of the rotor and above the permanent magnet, and converts magnetic signal information into a Hall output voltage signal by sensing a space air gap magnetic field on the upper surface of the permanent magnet synchronous linear motor;

the Hall position sensor is a linear Hall with six Hall signals.

2. The permanent magnet synchronous linear motor and hall position sensor based system according to claim 1, characterized in that the horizontal distance of the hall position sensor from the end of the mover is in the range of 5mm to 15 mm, and the vertical height of the hall position sensor from the upper surface of the permanent magnet is in the range of 5mm to 10 mm.

3. The permanent magnet synchronous linear motor and hall position sensor based system of claim 2, characterized in that the horizontal distance of the hall position sensor from the end of the mover is 10mm, and the vertical height of the hall position sensor from the upper surface of the permanent magnet is 7.5 mm.

4. The permanent magnet synchronous linear motor and hall position sensor based system of claim 1, characterized in that the permanent magnet of the stator is magnetized in the thickness direction, the magnet thickness of the permanent magnet ranges from 4mm to 6mm.

5. The PMSM and Hall position sensor based system according to claim 4, wherein the stator is disposed on a stator yoke of the PMSM, the stator yoke having a thickness in a range of 4mm to 8 mm.

6. The permanent magnet synchronous linear motor and hall position sensor based system of claim 5 wherein the magnet thickness of said permanent magnet is 5.5 mm and the thickness of said stator yoke is 6mm.

7. The PMSM and Hall position sensor based system according to claim 4, wherein the length of a single permanent magnet is 55mm, and the width of a single permanent magnet is 10 mm.

8. The permanent magnet synchronous linear motor and hall position sensor based system of claim 1 wherein the spacing distance between the plurality of permanent magnet N poles and permanent magnet S poles ranges from 1.5 mm to 3.5 mm.

9. The permanent magnet synchronous linear motor and hall position sensor based system of claim 1 wherein the spacing distance between the plurality of permanent magnet N poles and permanent magnet S poles is 2.5 millimeters.

10. The permanent magnet synchronous linear motor and hall position sensor based system of claim 1, characterized in that the permanent magnet is made of neodymium iron boron.

Technical Field

The invention relates to the technical field of sensors, in particular to a system based on a permanent magnet synchronous linear motor and a Hall position sensor.

Background

In the field of industrial applications, single-sided moving-coil Permanent Magnet Synchronous Linear Motors (PMSLMs) are widely used. The primary stage of the PMSLM is commonly referred to as the stator and the secondary stage as the mover. In order to realize the normal movement of the PMSLM, the movable stator of the PMSLM needs to be produced in different lengths, the short primary and the long secondary are the design forms which are usually adopted, and the difference of the lengths of the movable stator of the PMSLM is equivalent to the stroke range of the PMSLM. The PMSLM can directly realize linear motion, has the advantages of high precision, high speed, high power density, good dynamic response, compact motor structure and the like, and has wide application prospect in the fields of semiconductors, laser processing, integrated circuits and the like

At present, an alternating current control system based on PMSLM is commonly used in high-speed, fast-response and high-precision application occasions such as intelligent manufacturing, and a grating or a magnetic grating is generally used as a position detection unit to perform PMSLM high-precision motion control. However, such position sensors are expensive, high in installation requirements, limited in travel, and the like, which are not beneficial to the reliability of the PMSLM control system, and usually need to adopt a control mode of coordinate vector transformation, so that the calculation amount is large, the occupied storage space is large, and the performance requirements and the complexity of a hardware processing platform are increased.

Therefore, in view of the above technical problems, there is a need to provide a system based on a permanent magnet synchronous linear motor and a hall position sensor, which has high precision, low cost and simplified platform requirements.

Disclosure of Invention

In view of this, an object of the embodiments of the present invention is to provide a system based on a permanent magnet synchronous linear motor and a hall position sensor, in which the sensor is based on a hall effect principle, and combines a stator space structure and an electrical model of the permanent magnet synchronous linear motor, a signal generation structure design based on a linear hall sensor is performed, and the influence of a third harmonic on the measurement accuracy of the hall sensor is eliminated by using a "three-phase six hall" signal generation structure.

In order to achieve the above object, an embodiment of the present invention provides the following technical solutions: a system based on a permanent magnet synchronous linear motor and a Hall position sensor, the permanent magnet synchronous linear motor comprises: a mover and a stator; the stator comprises a permanent magnet, the permanent magnet comprises a plurality of permanent magnet N poles and permanent magnet S poles, and the permanent magnet N poles and the permanent magnet S poles are arranged at intervals and at equal intervals to form a fixed array; the Hall position sensor is arranged on the end face of the rotor and above the permanent magnet, and converts magnetic signal information into a Hall output voltage signal by sensing a space air gap magnetic field on the upper surface of the permanent magnet synchronous linear motor; the Hall position sensor is a linear Hall with six Hall signals.

Preferably, the horizontal distance range of the hall position sensor from the end of the mover is 5mm to 15 mm, and the vertical height range of the hall position sensor from the upper surface of the permanent magnet is 5mm to 10 mm.

Preferably, the horizontal distance between the hall position sensor and the end of the rotor is 10mm, and the vertical height between the hall position sensor and the upper surface of the permanent magnet is 7.5 mm.

Preferably, the permanent magnet of the stator is magnetized in the thickness direction, and the thickness range of the permanent magnet is 4-6 mm.

Preferably, the stator is disposed on a stator yoke of the permanent magnet synchronous linear motor, and a thickness of the stator yoke ranges from 4mm to 8 mm.

Preferably, the permanent magnet has a magnet thickness of 5.5 mm and the stator yoke has a thickness of 6mm.

Preferably, the length of each permanent magnet is 55mm, and the width of each permanent magnet is 10 mm.

Preferably, the spacing distance between the N pole and S pole of the permanent magnets is 1.5 mm to 3.5 mm.

Preferably, the spacing distance between the N pole and S pole of the permanent magnets is 2.5 mm.

Preferably, the permanent magnet is made of neodymium iron boron.

The invention has the following advantages:

according to the system based on the permanent magnet synchronous linear motor and the Hall position sensor, provided by the embodiment of the invention, a rectangular permanent magnet space magnetic field model of the stator is established according to the neodymium iron boron permanent magnet material selected by the permanent magnet synchronous linear motor and the stator structure of the single-sided motor, the magnetic field distribution of the stator permanent magnet of the permanent magnet synchronous linear motor is analyzed by combining finite element electromagnetic simulation, and the structural parameters such as the size of a stator magnetic yoke and a permanent magnet, the magnetic pole distance and the like are determined on the premise of ensuring the performance of the permanent magnet synchronous linear motor.

Furthermore, the system based on the permanent magnet synchronous linear motor and the hall position sensor provided by the embodiment of the invention is based on the hall effect principle and combines the stator space structure and the electric model of the permanent magnet synchronous linear motor, the signal generation structure design based on the linear hall sensor is carried out, and the influence of the third harmonic on the measurement precision of the position sensor is eliminated by adopting the three-phase six-hall signal generation structure.

Further, aiming at the influence of the space air gap magnetic field harmonic waves of the stator permanent magnet of the permanent magnet synchronous linear motor on linear Hall signals, finite element electromagnetic simulation analysis and Fourier magnetic field harmonic wave analysis are respectively carried out on the horizontal installation and the vertical installation of the space magnetic field of the permanent magnet synchronous linear motor position detection unit, the installation position of the Hall position sensor is optimized, the interference between a permanent magnet synchronous linear motor platform and the Hall position sensor is avoided to the maximum extent, the space air gap magnetic field of the permanent magnet synchronous linear motor is fully utilized, and therefore the integrated design concept of the permanent magnet synchronous linear motor and the Hall position sensor is achieved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments described in the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a schematic partial structural diagram of a single-sided permanent magnet linear synchronous motor according to an embodiment of the present invention;

FIG. 2 is a schematic view of the Hall sensor based on the single-side permanent magnet linear synchronous motor system in FIG. 1;

FIG. 3 is a schematic diagram of the operating principle of the single-sided permanent magnet linear synchronous motor according to the embodiment of the present invention;

fig. 4 is a schematic structural diagram of a stator permanent magnet of the unilateral permanent magnet linear synchronous motor according to the embodiment of the invention;

FIG. 5 is a schematic diagram of a structural model of a rectangular permanent magnet;

FIG. 6 is a schematic view of a magnetizing direction of a stator permanent magnet of the single-sided permanent magnet linear synchronous motor according to the embodiment of the present invention;

FIG. 7 is a schematic structural diagram of a stator permanent magnet of the single-sided permanent magnet linear synchronous motor according to the embodiment of the present invention;

FIG. 8 is a schematic diagram of the Hall effect principle;

FIG. 9 is a schematic diagram of a linear Hall characteristic curve selected for use in an embodiment of the present invention;

FIG. 10 is a schematic diagram of a signal structure design of a Hall displacement sensor according to an embodiment of the invention;

FIG. 11 is a schematic diagram of a theoretical waveform of a three-phase output signal of the Hall displacement sensor according to the embodiment of the invention;

fig. 12 is a schematic diagram of magnetic field harmonic distribution at different horizontal positions of an end portion of a mover of the single-sided permanent magnet linear synchronous motor in the embodiment of the present invention.

Detailed Description

In order to make those skilled in the art better understand the technical solution of the present invention, the technical solution in the embodiment of the present invention will be clearly and completely described below with reference to the drawings in the embodiment of the present invention, and it is obvious that the described embodiment is only a part of the embodiment of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

As shown in fig. 1 and 2, in this embodiment, the hall position sensor based system of the permanent magnet synchronous linear motor includes a permanent magnet synchronous linear motor 100 and a hall position sensor 200. The permanent magnet synchronous linear motor 100 includes a mover 10 (not shown) and a stator 12 (not shown).

As shown in fig. 1, the permanent magnet synchronous linear motor 100 includes a frame body. The frame body includes a mover stage 150, a slider 151, a slide rail 153, stator magnetic steel 155, and a stator yoke 157. The mover stage 150 is used to carry the mover 10 (not shown in the drawings) of the permanent magnet synchronous linear motor 100. The slider 151 is disposed below the mover stage 150 and linearly moves along the slide rail 153, so as to drive the mover stage 150 to linearly move. Below the mover stage 150, there are a stator magnetic steel 155 and a stator yoke 157, and the stator 12 is disposed on the frame body of the permanent magnet synchronous linear motor 100 through the stator yoke 157. As shown in fig. 2, the hall position sensor 200 is provided on an end surface of the mover stage 150, and the hall position sensor 200 may be considered to be provided on an end surface of the mover 10. The hall position sensor 200 is simultaneously located above the permanent magnet of the stator 12.

As shown in fig. 3, in operation, the mover 10 of the permanent magnet synchronous linear motor 100 directly drives in the direction of the traveling wave magnetic field under the action of the electromagnetic thrust formed between the mover and the stator 12. The hall position sensor 200 converts magnetic signal information into a hall output voltage signal by sensing a spatial air gap magnetic field of the upper surface of the permanent magnet synchronous linear motor 100. In addition, in order to enable the permanent magnet synchronous linear motor 100 to control the linear motion direction, the displacement direction of the permanent magnet synchronous linear motor 100 may be changed by phase sequence conversion control of A, B, C three-phase currents.

As shown in fig. 4, the permanent magnet structure of the stator of the permanent magnet synchronous linear motor 100 is schematically illustrated. The stator 12 may generate a magnetic field that varies in a fixed manner. The stator 12 includes permanent magnets including a plurality of permanent magnet N poles 121 and permanent magnet S poles 122. The permanent magnet N pole 121 and the permanent magnet S pole 122 are arranged in a fixed array at intervals and equal intervals. In the embodiment, the magnetic steel used by the permanent magnet is magnetized in the thickness direction, and the permanent magnet array is formed by uniformly arranging the N pole and the S pole of the permanent magnet according to the placement rule. The lower surface of the permanent magnet is attached to the surface of the stator yoke 157 by a metal adhesive through a designed fixture. The hall sensor 200 converts magnetic signal information into a hall output voltage by sensing a spatial air gap magnetic field of the upper surface of the stator permanent magnet of the permanent magnet synchronous linear motor 100. The control system detects the relative displacement of the controlled object in real time according to the voltage signal of the hall sensor 200.

Preferably, the material of the permanent magnet is neodymium iron boron. The remanence, the coercive force and the maximum energy product of the neodymium iron boron permanent magnet material are all higher than those of other rare earth permanent magnet materials, and the neodymium iron boron permanent magnet material is a permanent magnet material with the highest magnetic performance at present. Furthermore, the neodymium iron boron permanent magnet material is not easy to break and has low density, thereby being beneficial to the light weight and miniaturization of magnetic devices. The common neodymium iron boron permanent magnet material has the defects of high temperature coefficient and high possibility of being rusted for the neodymium iron boron permanent magnet material with ultrahigh coercivity, so that the surface coating treatment is required. Preferably, the permanent magnet is made of neodymium iron boron material with the trade name of N38H, and the main performance parameters of the parallel magnetizing nickel-plated magnetic steel are shown in Table 1.

TABLE 1N 38H Main Performance parameters

The magnetic induction coercive force of the neodymium iron boron material of N38H is above 916KA/m, the residual magnetism Br is 1.27T, and a ferrite material is selected for a stator magnet yoke part of the PMSLM, so that the problem of magnetic flux leakage of a magnetic circuit is reduced, the closure integrity of a magnetic circuit of a system is better, and the air gap magnetic density of the permanent magnet synchronous linear motor 100 is improved.

The stator permanent magnet of the permanent magnet synchronous linear motor 100 is used as a magnetic field excitation source, which not only affects the performance of the motor body of the permanent magnet synchronous linear motor 100, but also has a decisive influence on the integrated design of the hall position sensor 200 based on the linear motor. In order to better analyze the space magnetic field of the permanent magnet synchronous linear motor 100, the embodiment of the invention preliminarily establishes a mathematical model of the space magnetic field, and provides a theoretical model for the design analysis of the permanent magnet of the stator of the permanent magnet synchronous linear motor 100.

In this embodiment, neglecting the machining error and design difference of the stator permanent magnet, the stator permanent magnet is assumed to be an ideal rectangular permanent magnet with a size of L × W × H, and the uniform magnetization is in a saturated state. As shown in fig. 5, a rectangular permanent magnet model can be obtained by using an ampere molecular loop, and molecular current effects inside the rectangular permanent magnet can cancel each other out, so that, from a macroscopic perspective, the rectangular permanent magnet has only a surface current, and therefore, the entire space magnetic field outside the rectangular permanent magnet is excited only by a surface closed current loop ABCDA (defined as current intensity I), and then, the surface current density of a permanent magnet section parallel to the surface xoy can be represented as J1/h.

A certain point inside the rectangular permanent magnet is defined as (x)₀，y₀，z₀)，z₀And z₀+dz₀The two form a planar thin current loop, point P (x, y, z) is at any point outside the thin layer, dB is current loop A ' B ' C ' D ' A ' with intensity of Jdz₀The total magnetic field in the case of (a) can then be expressed as:

in the formula C 'D', dB_x、dB_yAnd dB_zThe magnetic field components generated in the respective directions for current loop a ' B ' C ' D ' a ' at point P can also be expressed as the sum of the respective magnetic field components of the four current segments a ' B ', B ' C ', C ' D ', D ' a '. Therefore, dB is taken as an example of the A 'B' current segment_yAnd dB_zAnalysis of the theoretical formula, in this case x₀＝L。

Definition r is the radial path of the point where the current element points to the point P, as defined by the Bio Saval law

In the formula, μ 0 ═ 4 π × 10-7, the permeability in vacuum was determined. Can obtain the product

dB of four current segments of B ' C ', C ' D ' and D ' A_xi、dB_yiAnd dB_ziThe term (i) can be determined in the same manner as in (2, 3, 4). Setting psi_iIs a use of psi₁，ψ₂，ψ₃Function notation as argument and defines:

then it can be obtained

Definition Γ is a number γ₁,γ₂,γ₃As a function of the argument, phi is a function of gamma₁,γ₂,γ₃The function notation as an argument, the function formula is as follows:

then, the total magnetic field of the rectangular permanent magnet ABCDA at any point outside it can be expressed as:

namely, the air gap magnetic field mathematical model under the ideal condition of the stator permanent magnet of the permanent magnet synchronous linear motor 100 can be obtained by the above principle analysis of the hall effect, and the voltage output signal of the hall sensor is only equal to the B of the permanent magnet space magnetic field_yThe components are related. And is composed of B_yThe mathematical model shows that, under the ideal condition of not considering magnetic field coupling, the size of the stator permanent magnet and the air gap are main factors of the magnetic induction intensity of the permanent magnet space magnetic field, the overall linear motor stator is considered, the size distribution of the magnetic induction intensity is also influenced by the distance between the permanent magnets (directly embodied by the magnetic pole distance), and the air gap is a key parameter influencing the size of the magnetic induction intensity.

As shown in fig. 6, the stator field permanent magnets of the permanent magnet synchronous linear motor 100 are magnetized in the thickness direction (i.e., in the direction of the arrow in the figure), and are arranged on the stator yoke 157 at equal intervals according to the NS rule. As shown in fig. 7, the plurality of permanent magnets N and S are spaced apart by a distance ranging from 1.5 mm to 3.5 mm. The magnitude of the magnetic induction at any point in space is mainly determined by the dimensions of the rectangular permanent magnet and the air gap. In the embodiment of the invention, the size of a single permanent magnet is optimized by combining a Hall magnetic field signal source with the magnetic pole distance and the air gap from the design of a linear motor. Considering the linear motor structure, the actual process, and the like, the thickness of the stator yoke 157 ranges from 4mm to 8 mm, and preferably the thickness of the stator yoke is 6mm. The thickness control of a single permanent magnet is to prevent magnetic flux leakage from being formed inside the magnetic steel, and the thickness is usually 4 mm-6 mm. According to the practical application and simulation optimization of the linear motor, the thickness of a single permanent magnet is preferably 4.5 mm. The design of the motor moving stator requires consistent coupling area, so that full utilization is guaranteed, the utilization rate of the length of the permanent magnet is controlled, the width of the permanent magnet controls the pole arc coefficient, and the tooth space force of the linear motor is reduced. In this embodiment, the individual permanent magnets are 55mm by 10mm in length and width dimensions and 2.5mm apart by the motor design.

According to the Hall position sensor based on the permanent magnet synchronous linear motor, provided by the embodiment of the invention, a rectangular permanent magnet space magnetic field model of a stator is established according to the neodymium iron boron permanent magnet material selected by the permanent magnet synchronous linear motor and a single-side motor stator structure, the magnetic field distribution of the stator permanent magnet of the permanent magnet synchronous linear motor is analyzed by combining finite element electromagnetic simulation, and the structural parameters such as a stator yoke, the size of a permanent magnet, the magnetic pole distance and the like are determined on the premise of ensuring the performance of the permanent magnet synchronous linear motor.

The hall effect is a magnetoelectric effect discovered by the hall of american physicist in 1879. As shown in fig. 8, it is a schematic diagram of the N-type semiconductor hall effect. If the current on both sides is I and a magnetic field with magnetic induction intensity of B and vertical to the upper and lower surfaces of the semiconductor exists, the carriers in the chip are deflected due to Lorentz force, and Hall electric fields are formed on the upper and lower edges of the chip. In a steady state, the carriers continue to move in the initial direction, generating hall voltages at the upper and lower edges of the hall element. Hall sensors are magneto-sensitive elements that can be used in the design of position detection units based on the hall effect.

The hall sensor may be classified into a switching hall outputting a digital signal and a linear hall outputting an analog signal. The linear hall can feed back a corresponding voltage signal according to the magnitude of magnetic induction in the working environment, and as shown in fig. 9, an output characteristic curve thereof is provided. The slope of the curve corresponds to the sensitivity of the linear Hall, the change of the magnetic field intensity can be well detected in real time, the high sensitivity is realized, the weak magnetic field change can be accurately tracked, and millivolt-level analog signals can be processed.

In this embodiment, in order to better realize high-precision position feedback based on the PMSLM detection unit, the detection unit is designed with a linear hall sensor as a magneto-sensitive element, and the hall position sensor 200 is a linear hall with six hall signals. Preferably, the hall position sensor 200 is selected from CH604ASR by Cosemitech, which has a wide operating voltage and can output linearly. The Hall element is internally integrated with a signal amplifying circuit without external connection, the circuit design is flexible, the circuit structure of the displacement sensor is simplified, the product cost is reduced, the structure is compact as much as possible, and the influence of mechanical stress or thermal stress on output is reduced to the greatest extent by the square Hall sensing element.

As shown in fig. 10, the hall position sensor 200 in the embodiment of the present invention has a six-hall signal detection structure. At present, in a signal processing technology, the third harmonic wave is not eliminated well, so that the influence of the third harmonic wave on the measurement precision of a sensor is mainly analyzed in the design of a signal detection structure.

According to the magnetic field analysis, the magnetic field generated by the magnetic steel is a sine signal, and the Hall output signal is also a sine wave and can be expressed as

Where λ is the pitch, V is the voltage amplitude, and x is the displacement. Considering the nonlinearity of the magnetic field, the mechanical error, random interference and zero drift exist in practical conditions, and the output voltage signal of the Hall element can be expressed as

In the formula, epsilon is an amplitude change coefficient, delta is zero drift, and xi is a random error.

Taking into account the non-linearity of the magnetic field, the signal induced by the Hall element A +Contains DC offset and higher harmonics, and can be expressed as

In which Δ is the DC offset (V) of the signal_iIs the ith signal amplitude (V). The same way can obtain the A-induced signalCan be expressed as

For the signalAndv is obtained by diameter difference processing_a(mainly considering the 2,3, 4 harmonics) of

In the same way, can obtain

Sequentially adding the formulas in the formula 2.28 to obtain

Because for any displacement, there are

Thus, equation 2.29 translates to

The third harmonic component in the signal is thus calculated as

The theoretically original sampled signal v_a、v_b、v_cThe third harmonic can be eliminated by respectively subtracting the formula 2.32 to obtain a three-phase theoretical sinusoidal signal V_A、V_B、V_CCan be expressed as

Therefore, the signal theoretical output waveform after three-phase signal normalization is shown in fig. 11.

The Hall position sensor based on the permanent magnet synchronous linear motor provided by the embodiment of the invention is based on the Hall effect principle and combines the stator space structure and the electric model of the permanent magnet synchronous linear motor, the signal generation structure design based on the linear Hall sensor is carried out, and the influence of the third harmonic on the measurement precision of the position sensor is eliminated by adopting the three-phase six-Hall signal generation structure.

Since the hall sensor utilizes the stator permanent magnet space magnetic field of the permanent magnet synchronous linear motor 100 itself and its own characteristics, it can be preliminarily seen that the hall linear position sensor can be better integrated with the linear motor system, as shown in fig. 2. However, since the position sensor is tightly combined and the measurement accuracy of the linear hall-based position sensor is directly affected by the magnetic field intensity, and the spatial distribution of the stator magnetic field of the permanent magnet synchronous linear motor 100 is affected by the harmonic characteristics of the magnetic field signal caused by the motor structure and the end effect thereof, the spatial magnetic field at the installation position of the hall sensor needs to be analyzed and optimized, and the horizontal position is the primary factor affecting the magnetic field harmonic.

The air-gap space magnetic field harmonics of the permanent magnet synchronous linear motor 100 mainly include armature winding magnetomotive force harmonics, permanent magnet magnetomotive force harmonics, and air-gap permeance harmonics (including cogging harmonics and end-effect harmonics). The direct coupling air gap space magnetic field of the moving stator of the permanent magnet synchronous linear motor 100 is greatly influenced by magnetomotive force harmonic waves and cogging harmonic waves of armature windings, and the influence of the harmonic waves on the excitation signal quality of the Hall magnetic field can be greatly reduced because the Hall sensor is arranged at the near end of the end part of the moving rotor of the permanent magnet synchronous linear motor 100 in the initial stage.

As shown in fig. 12, in the embodiment of the present invention, magnetic field harmonic distribution simulation and fourier analysis are performed at a distance of 0mm, 5mm, 10mm, 20mm, and the like from the mover end when the permanent magnet synchronous linear motor 100 is in an idle state. As can be seen from fig. 12, when the end portion of the mover is close, the second harmonic, the third harmonic, and the like have high proportions, and start to be significantly reduced when the distance is close to 10mm, and the specific data of various magnetic field harmonics in percentage of the fundamental wave in table 2 are combined, so that the magnetic field harmonics in percentage of the fundamental wave sharply decreases and the influence of the magnetic field harmonics is weakened when the hall sensor moves from 0mm to 10mm based on the horizontal installation position of the end portion of the permanent magnet synchronous linear motor 100; in the process of moving from 0mm to 30mm, the magnetic field harmonic accounts for the percentage of the fundamental wave and is in a generally downward trend but is in a gentle trend. In consideration of the integrated structure design of the actual permanent magnet synchronous linear motor 100, the horizontal distance between the hall position sensor 200 and the end of the rotor ranges from 5mm to 15 mm. Preferably, the distance between the first hall position sensor 200 in the final hall array and the horizontal installation position of the permanent magnet synchronous linear motor 100 is 10 mm.

TABLE 2 percent (%) of fundamental in the magnetic field harmonic Fourier analysis

The permanent magnets on the stator magnetic yoke 157 of the permanent magnet synchronous linear motor 100 are uniformly distributed according to N, S rule, and the air gap space magnetic field of the stator permanent magnets of the permanent magnet synchronous linear motor 100 has certain regularity and changes along with the horizontal and height directions. According to the detection principle, the Hall sensors are arranged in a certain arrangement mode and can output magnetic field signals to realize position measurement. The above analysis and optimization of the horizontal installation position of the sensor on the system magnetic field harmonic distribution of the hall permanent magnet synchronous linear motor 100 is that whether the hall sensor can accurately measure the magnetic field strength of the current position is the key of the detection precision of the motor position, that is, it is only required to ensure that the sensor is located in a proper output magnetic field range, so that the optimization of the air gap height of the hall sensor needs to be performed by combining the system magnetic field strength distribution of the hall permanent magnet synchronous linear motor 100.

The magnetic induction intensity of a space magnetic field above the stator permanent magnet is changed in a regular sine shape, an ideal sine and cosine signal is generated at a certain air gap height, and in addition, the magnetic induction intensity of the space magnetic field above the stator permanent magnet is rapidly weakened in the magnetizing direction along with the rise of the height above the stator permanent magnet. In order to determine the optimal air gap height of the Hall sensor detection unit in the system space magnetic field of the permanent magnet synchronous linear motor 100, the air gap between the magnetic steel and the Hall element is adjusted to observe the magnetic field intensity at the air gap between the magnetic steel and the Hall element.

If the distance between the hall position sensor 200 and the permanent magnet of the stator of the permanent magnet synchronous linear motor 100 is too high (namely the height of the air gap is too large), the hall output voltage signal corresponding to the weak magnetic induction intensity is small, which is not beneficial to the processing of the hall displacement voltage signal and the utilization rate of the AD module; if the distance above the stator permanent magnet of the permanent magnet synchronous linear motor 100 of the detection unit is too low (i.e. the height of the air gap is too small), the magnetic induction intensity is relatively strong, and the output peak of the hall displacement voltage signal is "flattened" to cause detection errors.

Considering that the analog voltage input range of the built-in analog-to-digital conversion module of the microprocessor is 0-3.6V, the working voltage is 3.3V, and in order to improve the measurement accuracy and the resolution of the sensor, the voltage output variation range of the Hall sensor should be as close to 3.3V as possible. In addition, the use of the AD conversion module directly affects the resolution of the linear hall detection unit, and the range utilization rate of the AD conversion module is generally more than 0.67 to improve the detection resolution. According to the selected CH604ASR linear Hall characteristic and the temperature drift factor, the peak value of a voltage signal induced by the Hall sensor is most appropriate to be 2.7-3.1V, magnetic leakage exists in the PMSLM stator permanent magnet in the actual situation, and the optimal range of the corresponding magnetic field intensity is 1000-1200G.

The air gap height of the linear Hall sensor is suitable under the condition of keeping the proper horizontal position under the condition of the maximum magnetic field density of the air gap height within the range of 6.6-8.0mm, under the condition of the air gap height of 7.5mm, the maximum magnetic density value is 1107G, and in consideration of actual manufacturing and installation. The vertical height of the hall position sensor 200 from the surface above the permanent magnet ranges from 5mm to 10 mm. Preferably, the vertical height of the hall position sensor from the surface above the permanent magnet is 7.5 mm.

In the embodiment of the invention, aiming at the influence of the space air gap magnetic field harmonic wave of the stator permanent magnet of the permanent magnet synchronous linear motor on the linear Hall signal, the horizontal installation and the vertical installation of the permanent magnet synchronous linear motor position detection unit in the space magnetic field are respectively subjected to finite element electromagnetic simulation analysis and Fourier magnetic field harmonic wave analysis, the installation position of the Hall position sensor is optimized, the interference between a permanent magnet synchronous linear motor platform and the Hall position sensor is avoided to the maximum extent, the space air gap magnetic field of the permanent magnet synchronous linear motor is fully utilized, and the structural compactness of the permanent magnet synchronous linear motor and the integrated design concept of the Hall position sensor are realized.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.