Linear Hall position detection method for secondary segmented primary permanent magnet linear motor

Abstract

The invention discloses a method for detecting a linear Hall position of a secondary segmented primary permanent magnet linear motor, which comprises the following steps of: embedding a linear Hall element in a primary groove for placing an armature winding between permanent magnet magnetic conductive teeth and armature winding magnetic conductive teeth of the linear motor to detect the position; the detection method provided by the invention comprises the following steps of: acquiring a voltage signal which contains position information and has less direct-current components and even harmonics by adopting a linear Hall installation method provided by the invention; odd-order harmonics in the voltage signals used for position calculation are filtered out through a designed complex filter; and full-speed position detection is realized through a phase-locked loop containing a self-adaptive complex filter. According to the method, only the primary embedded linear Hall element is adopted, on the basis that the structure of the primary permanent magnet linear motor is kept unchanged, the secondary segmented structure is used for position detection, the method has the advantages of being low in cost and high in reliability, and the method can further achieve rapid and accurate tracking of the position of the secondary segmented primary permanent magnet linear motor.

Description

Technical Field

[0001] The present invention relates to a position detection method for a secondary-segmented primary permanent magnet linear motor based on a linear Hall. The secondary structure of the secondary-segmented primary permanent magnet linear motor is simple, and the cost of the position detection device based on the linear Hall is relatively low. For the secondary-segmented primary permanent magnet linear motor adopting the position detection method based on the linear Hall of the present invention, in fields such as numerical control machine tools, precision positioning systems, industrial servo systems, and long-distance linear traction rail transit systems, the costs of the motor body and the control system can be greatly reduced. Background Art

[0002] Linear motors have been widely used in many fields requiring high precision, high speed, and high stability. In places such as automated production lines, numerical control machine tools, industrial servo systems, and precision positioning systems, since they do not rely on traditional mechanical transmission components, they provide higher work efficiency and lower maintenance requirements. In maglev trains and high-speed railways, linear motors provide power for the systems, ensuring smooth and contactless operation. In addition, linear motors have also been widely used in high-tech industries such as aerospace, medical equipment, and motion simulators, promoting technological innovation and development in various industries through precise linear drive and efficient energy conversion. Currently, linear motors have been used in urban rail transit fields such as the Guangzhou Metro and the Capital Airport. In 2023, the linear motor of CRRC Zhuzhou Electric Locomotive Co., Ltd. on the Capital Airport Line passed the 50,000-kilometer operation assessment, further demonstrating the advantages of linear motors. Linear motors adopt a non-adhesive structure, with less frictional loss, and have the advantages of strong climbing ability, small turning radius, low noise, and simple maintenance. Particularly importantly, linear motors eliminate mechanical conversion devices, greatly reducing the manufacturing cost. Linear motors are divided into linear induction motors, permanent magnet linear motors, and linear switched reluctance motors. The stator structures of linear induction motors and linear switched reluctance motors are simple and easy to maintain, but the air gap between the primary and secondary is large, resulting in low power density, low efficiency, large thrust fluctuation, and high noise. In traditional permanent magnet linear motors, the permanent magnets and armature windings are respectively placed on the primary and secondary sides. Whether the permanent magnets or the armature windings are laid along the track, it will increase the secondary cost and reduce the reliability of the system, making it unsuitable for long-distance industrial systems. The new type of primary permanent magnet linear motor has the characteristics of high efficiency and high power density. The secondary stator is composed of iron cores, and the primary mover is only composed of permanent magnets and armature windings, with a simple structure, convenient maintenance, and lower manufacturing cost, having broad application prospects in the industrial system field. The control of high-performance and high-reliability primary permanent magnet linear motors requires accurate mover position information and rotational speed information.

[0003] The current position detection methods for motors can be divided into sensorless control and sensor-based control according to the presence or absence of position sensors. Sensorless control does not use position sensors and is very suitable for occasions where position sensors cannot be installed. However, it is impossible to use a single algorithm to detect the position of the motor throughout the entire speed range. Therefore, it is divided into medium-high speed position detection and zero-low speed position detection according to the speed range, which increases the complexity of the motor position detection algorithm. At the same time, sensorless control is highly sensitive to motor parameters, which will reduce the robustness of the entire drive system. Especially when the system fails, the reliability of sensorless control that relies on system parameters is even lower.

[0004] The position detection methods with position sensors can be divided into resolver, magnetoresistive, optoelectronic, magnetic grating, eddy current and Hall types. The resolver has a very high resolution, but its structure is not suitable for linear motors. The magnetoresistive type has strong environmental adaptability, but its effect signal is weak, it is difficult to collect effective signals, and large position detection errors are likely to occur. The optoelectronic type can track quickly and has a high resolution. The magnetic grating type has a high resolution and stronger environmental adaptability than the optoelectronic type. At present, the primary permanent magnet linear motor mainly uses expensive grating rulers and magnetic grating rulers to obtain the position information of the mover. However, these two position detections are a ruler-like structure laid on the secondary, and its length is the same as that of the secondary. When detecting the position of the linear motor in the context of a long-distance industrial system, the cost is high. The eddy current type has strong environmental adaptability, but the structure of the secondary teeth of the linear motor causes inconsistent air gap heights, which will seriously affect the accuracy of position detection. The Hall position sensor has a small structure, low cost, and strong environmental adaptability, and is very suitable for the position detection of linear motors in the industrial system field.

[0005] To address the above problems, the present invention proposes a position detection method for a secondary-segmented primary permanent magnet linear motor based on a linear Hall element. A linear Hall element 2 for motor position detection is embedded in the primary slot where the armature winding 111 is placed between the permanent magnet magnetic conduction teeth and the armature winding magnetic conduction teeth of the primary 11 of the primary permanent magnet linear motor. The linear Hall element (2) remains relatively stationary and moves synchronously with the primary of the linear motor. Without changing the structure of the linear motor, the cost of the linear motor position detection facility is reduced. At the same time, the Hall sensor has a simple structure, eliminating the need for complex position detection devices and facilitating maintenance. By using an optimized position calculation algorithm to calculate the Hall output voltage signal, it is possible to quickly and accurately track the position information of the linear motor throughout the entire speed range. Summary of the Invention

[0006] The object of the present invention is to address the deficiencies of the above-mentioned background technology and provide a position detection method for a secondary-segmented primary permanent magnet linear motor suitable for the background of industrial systems, thereby solving the problems of poor environmental adaptability and high cost of traditional position detection methods.

[0007] The present invention adopts the following technical solutions to achieve the above-mentioned invention objectives:

[0008] A secondary segmented primary permanent magnet linear motor, the linear motor comprising: a primary 11 and a secondary 10, both the primary 11 and the secondary 10 being made of magnetic conductive materials and having an air gap therebetween, the primary 11 being provided with magnetic conductive teeth 110, armature windings 111 and permanent magnets 112 being alternately arranged on the magnetic conductive teeth 110, the permanent magnets 112 being placed at the bottom of the magnetic conductive teeth 110, adjacent permanent magnets 112 being separated by two primary pole pitches and having opposite magnetization directions.

[0009] The magnetic conductive teeth 110 on which the armature windings 111 are placed are called armature winding magnetic conductive teeth, and the magnetic conductive teeth 110 on which the permanent magnets 112 are placed are called permanent magnet magnetic conductive teeth.

[0010] In the primary slots where the armature windings 111 are placed between the permanent magnet magnetic conductive teeth and the armature winding magnetic conductive teeth, linear Hall elements 2 for motor position detection are provided. The linear Hall elements 2 remain relatively stationary and move synchronously with the primary 11 of the linear motor.

[0011] Further, the number of magnetic conductive teeth 110 of the primary 11 of the linear motor is 4mnj + 1, and the distance between the center lines of adjacent magnetic conductive teeth 110 is the primary pole pitch τ p ; 2mnj armature windings 111 and 2mnj + 1 permanent magnets 112 are provided on the magnetic conductive teeth 110, and the secondary 10 is provided with segmented magnetic conductive blocks, and the distance between the center lines of adjacent segmented magnetic conductive blocks is the secondary pole pitch τ s The primary and secondary pole pitches satisfy the following formula:

[0012] The linear motor is composed of n motor units, where L ef is defined as a motor unit, and each motor unit is composed of 2mj permanent magnet magnetic conductive teeth and 2mj armature winding magnetic conductive teeth. Any one-phase armature winding in the motor unit is composed of j pairs of armature windings 111 connected in series. Starting from the first armature winding 111, a total of j armature windings 111 placed on adjacent armature winding magnetic conductive teeth belong to the same phase. Subsequently, j armature windings 111 of adjacent phases are arranged in sequence on the armature winding magnetic conductive teeth. According to the above arrangement method, 2*j armature windings 111 belonging to the same phase form j pairs of complementary armature windings, and the relative positions of the two armature windings 111 in any pair of armature windings differ by half of the secondary pole pitch with respect to the secondary 10.

[0013] where τ p is the primary pole pitch, τ sδ is the secondary pole pitch, m is the number of phases of the motor, n is the number of motor units, j is the number of pairs of armature windings 111 connected in series in a single phase in a motor unit, and q is the number of armature windings connected in series in a single phase in a motor unit.

[0014] Further, there are 2*j groups of linear Hall elements 2 provided in the linear motor. Each group of linear Hall elements contains m linear Hall elements 2, and the outputs of the m linear Hall elements 2 are m-phase position information. The position information of any phase of the linear motor is composed of the superposition of the outputs of j pairs of linear Hall elements 2. Starting from the first linear Hall element 2, there are j linear Hall elements 2 placed at adjacent positions that belong to the same phase. Subsequently, j linear Hall elements 2 belonging to adjacent phases are arranged in sequence. According to the above arrangement method, the 2*j linear Hall elements 2 belonging to the same phase form j pairs of complementary linear Hall elements, and the interval between the two linear Hall elements 2 in any pair of linear Hall elements is (2k + 1)×0.5×τ s , where k = 0, 1, 2, 3,..., and k is a natural number.

[0015] Based on the above secondary-segmented primary permanent magnet linear motor, the present application also provides a motor position detection method, which includes the following specific steps:

[0016] Step 1: Select linear Hall elements, with m as a group. According to the number of pairs of armature windings connected in series in a single phase in a motor unit, they are divided into 2*j groups and installed at the set positions of the primary 11 slots between the permanent magnet magnetic conduction teeth and the armature winding magnetic conduction teeth. The linear Hall elements 2 convert the magnetic signals at the specified positions into electrical signals;

[0017] Step 2: Combine the m-phase electrical signals obtained in Step 1 to obtain an m-phase voltage signal containing position information with less harmonic content;

[0018] Step 3: Perform Clarke transformation on the m-phase voltage signal containing harmonics obtained in Step 2 to obtain the voltage u α and u β in the two-phase stationary coordinate system;

[0019] Step 4: Use an optimized adaptive complex filtering algorithm to filter the voltage u α and u β containing harmonics, extract the positive-sequence voltages and , and then use a phase-locked loop decoding algorithm for position calculation, so as to realize the full-speed segment position detection and tracking of the linear motor.

[0020] Further, the set positions of the primary 11 slots between the permanent magnet magnetic conduction teeth and the armature winding magnetic conduction teeth are:

[0021] The 2*j linear Hall elements 2 belonging to the same phase form j pairs of complementary linear Hall elements, and the distance between two linear Hall elements 2 in any pair of linear Halls is (2k + 1)×0.5×τ s , where k = 0, 1, 2, 3, …, and k is a natural number.

[0022] Furthermore, in the step 1, the electrical signals are named. The first group is named A1, B1, C1 …… m1, the second group is named A2, B2, C2 …… m2, where m is the number of phases of the motor, and there are 2*j groups in total, and so on;

[0023] The numerical value of the voltage signal output by superimposing A1 and A2 …… Aq is used as the A phase, the numerical value of the voltage signal output by superimposing B1 and B2 …… Bq is used as the B phase, the numerical value of the voltage signal output by superimposing C1 and C2 …… Cq is used as the C phase, and so on, that is, the m-phase voltage signal containing harmonics.

[0024] Furthermore, the number of pairs j of the armature windings 111 connected in series in a single phase in one motor unit belongs to N + .

[0025] Furthermore, for the set position of the primary 11 slots installed between the permanent magnet magnetic teeth and the armature winding magnetic teeth, the installation method is as follows:

[0026] (1) Installation method of linear Hall elements in the same group: The m linear Hall elements 2 in the same group construct m-phase symmetric voltage signals. The mechanical distance between adjacent linear Hall elements 2 of the m-phase motor is 2*τ p , where τ p is the primary pole pitch in the secondary segmented primary permanent magnet linear motor, and τ s is the secondary pole pitch. For a common three-phase motor, use τ s / 3 + k×τ s , τ s / 6 + k×τ s , 2×τ s / 3 + k×τ s , 5×τ s / 6 + k×τ s installation method, where k = 0, 1, 2, 3, … and k is a natural number. The four different installation methods are transformed to obtain the standard three-phase signals;

[0027] (2) Installation method of linear Hall elements in different groups: The 2*j linear Hall elements 2 belonging to the same phase form j pairs of complementary linear Hall elements, and the distance between two linear Hall elements 2 in any pair of linear Halls is (2k + 1)×0.5×τ s , where k = 0, 1, 2, 3, …, and k is a natural number, and the installation positions of the 2*j*m linear Hall elements 2 do not coincide.

[0028] Further, in the step 4, the mathematical model expression of the adaptive complex filter is as follows

[0029]

[0030] where a ≤ n, a ∈ N + , i ∈ N + , n ∈ N + , where \(\hat{\omega}\) is the output angular velocity of the phase-locked loop, and \(\omega\) c is the cut-off frequency, is the positive sequence component of the i-th harmonic, is the negative sequence component of the i-th harmonic, and \(U\) αβ (s) is the total voltage component containing harmonics.

[0031] The present invention has the following beneficial effects:

[0032] 1) A linear Hall element 2 for motor position detection is provided in the primary slot where the armature winding 111 is placed between the magnetic teeth of the permanent magnet and the magnetic teeth of the armature winding of the linear motor. The linear Hall element 2 remains relatively stationary and moves synchronously with the primary 11 of the linear motor. There is no permanent magnet in the secondary of the motor and no additional position detection device, which can effectively reduce the cost of the position detection device in the field of long-distance linear drive.

[0033] 2) Through the primary embedded Hall position installation method of the present invention, combined with the magnetic circuit complementary characteristics of the primary permanent magnet linear motor, j pairs of complementary linear Hall signals are superimposed to reduce the influence of the DC error and even harmonic error caused by the magnetic circuit asymmetry on the measurement accuracy. Without changing the motor structure, through this Hall installation method, the accuracy of position detection is improved.

[0034] 3) The present invention adopts a phase-locked loop with an adaptive complex filtering algorithm. When the motor runs at variable speed, the cut-off frequency of the filter changes adaptively, improving the filtering effect and enhancing the accuracy of position detection on the improved software algorithm structure.

[0035] 4) The present invention is also applicable to other types of linear motors. Description of the Drawings

[0036] The present invention will be further described below with reference to the drawings and embodiments:

[0037] Figure 1 is the block diagram of the vector control system of the primary permanent magnet linear motor based on linear Hall position detection;

[0038] Figure 2 is the explanatory diagram of the primary embedded linear Hall installation method within the same group;

[0039] Figure 3 (a) is the cross-sectional view of the motor in Embodiment 1

[0040] Figure 3 (b) is the cross-sectional view of the motor in Embodiment 2;

[0041] Figure 4 is the no-load back electromotive force waveform diagram of phase A;

[0042] Figure 5 is the slot opening installation position diagram of the motor in Embodiment 1;

[0043] Figure 6 is the Br simulation diagram and FFT diagram of the linear Hall in the no-load operating state of the motor in Embodiment 1;

[0044] Figure 7 is the Br simulation diagram and FFT diagram of the linear Hall in the rated operating state of the motor in Embodiment 1;

[0045] Figure 8 is the position calculation block diagram containing an optimized adaptive complex filter;

[0046] Figure 9 (a) is the phase tracking diagram when the motor in Embodiment 1 operates at no-load and variable speed;

[0047] Figure 9 (b) is the phase tracking diagram when the motor in Embodiment 1 operates at rated load and variable speed;

[0048] Figure 10 is the slot opening installation position diagram of the motor in Embodiment 2;

[0049] Figure 11 (a) is the simulation diagram of the radial magnetic density (Br) of the two groups of linear Hall elements superimposed in the motor in Embodiment 2;

[0050] Figure 11 (b) is the FFT result diagram of Br of the two groups of linear Hall elements superimposed in the motor in Embodiment 2;

[0051] Figure 12 (a) is the simulation diagram of the radial magnetic density (Br) of the two groups of linear Hall elements superimposed in the motor in Embodiment 2;

[0052] Figure 12 (b) is the FFT result diagram of Br of the two groups of linear Hall elements superimposed in the motor in Embodiment 2;

[0053] Figure 13 (a) is the phase tracking diagram when the motor in Embodiment 2 operates at no-load and variable speed;

[0054] Figure 13 (b) is the phase tracking diagram when the motor in Embodiment 2 operates at rated load and variable speed;

[0055] Figure 14It is the slot installation position diagram of the motor in Embodiment 3;

[0056] Figure 15 It is the phase tracking diagram when the motor in Embodiment 3 runs;

[0057] Figure 16 It is the slot installation position diagram of the motor in Embodiment 4;

[0058] Figure 17 It is the phase tracking diagram when the motor in Embodiment 4 runs;

[0059] Wherein, 10 - secondary, 11 - primary, 110 - magnetic conducting teeth, 111 - armature winding, 112 - permanent magnet, 2 - linear Hall element. Specific Embodiment

[0060] The technical solution of the invention will be described in detail below with reference to the drawings. The technical solution in the embodiment of the present invention is further clearly and completely described. It should be noted that the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0061] On the basis of not changing the structure of the primary permanent magnet linear motor, the proposed installation method of the embedded linear Hall 2 in the linear motor is adopted. The embedded linear Hall element 2 is installed in the primary slot with the armature winding 111 placed between the magnetic conducting teeth of the permanent magnet and the magnetic conducting teeth of the armature winding of the linear motor. The linear Hall element 2 remains relatively stationary and moves synchronously with the primary 11 of the linear motor to obtain a voltage signal containing position information with lower harmonic content. At the same time, the phase-locked loop position decoding algorithm with an optimized adaptive complex filtering algorithm is used for position calculation to obtain accurate mover position information. Through simulation experiments, the present invention can track quickly and accurately on the basis of reducing the cost of the position detection system.

[0062] For the position detection of the commonly used secondary segmented primary permanent magnet linear motor based on the linear Hall element 2, the following steps are included:

[0063] When the number of phases of the motor m = 3 and the number of pairs of the armature windings 111 connected in series in a single-phase in a motor unit j = 1, there are 2*j*m = 2*3 linear Hall elements 2 at this time.

[0064] Step 1: Select six linear Hall elements 2, divide them into two groups. The first group is labeled D1, D2, D3, and the second group is labeled D4, D5, D6. Install them at the specified positions in the primary slot with the armature winding 111 placed between the magnetic conducting teeth of the permanent magnet and the magnetic conducting teeth of the armature winding of the linear motor. The magnetic signals at the specified positions are converted into electrical signals through the linear Hall elements 2.

[0065] The installation method of the embedded linear Hall is as follows:

[0066] (1) Installation method of linear Hall in the same group: Three linear Hall sensors in the same group construct three-phase symmetrical voltage signals. Commonly, the three phases have a phase difference of τ s / 3 + k×τ s mechanical distance, where k = 0, 1, 2, 3, …, k is a natural number. The primary structure of the motor may cause it impossible to install according to the τ s / 3 + k×τ s installation method. Since k = 0, 1, 2, 3, …, k is a natural number, three new installation methods are proposed, namely using τ s / 6 + k×τ s mechanical distance, 2×τ s / 3 + k×τ s mechanical distance, and 5×τ s / 6 + k×τ s mechanical distance installation methods, where k = 0, 1, 2, 3, …, k is a natural number. Since the mechanical angles between the three linear Hall sensors are different, the linear Hall encoder numbers for the three-phase 120° voltage signals ABC change.

[0067] 1) For the τ s / 3 + k×τ s installation method, select the output voltage signal of D1 as phase A, the output voltage signal of D2 as phase B, and the output voltage signal of D3 as phase C;

[0068] 2) For the τ s / 6 + k×τ s installation method, select the output voltage signal of D1 as phase A, the output voltage signal of D3 as phase B, and take the inverse of the output voltage signal of D2 as phase C;

[0069] 3) For the 2×τ s / 3 + k×τ s installation method, select the output voltage signal of D1 as phase A, the output voltage signal of D3 as phase B, and the output voltage signal of D2 as phase C;

[0070] 4) For the 5×τ s / 6 + k×τ s installation method, select the output voltage signal of D1 as phase A, take the inverse of the output voltage signal of D2 as phase B, and take the inverse of the output voltage signal of D3 as phase C;

[0071] (2) Installation method of linear Hall in different groups: The difference between D1 and D4 is (2k + 1)×0.5×τ s mechanical distance, where k = 0, 1, 2, 3, …, k is a natural number. The difference between D2 and D5 is (2k + 1)×0.5×τ sMechanical distance, k = 0, 1, 2, 3, …, k is a natural number, and the difference between D3 and D6 is (2k + 1)×0.5×τ s Mechanical distance, k = 0, 1, 2, 3, …, k is a natural number, that is, the difference is an odd multiple of half the pole pitch, and the installation positions of the six linear Hall elements do not coincide.

[0072] Step 2: Use a digital signal processor to convert the output voltage signals of the six linear Hall elements 2 obtained in Step 1 into digital signals through an analog-to-digital converter. Combine different installation methods to transform the voltage signals output by the six linear Hall elements 2 to obtain two sets of three-phase ABC signals. The first set is named A1, B1, C1, and the second set is named A2, B2, C2.

[0073] Step 3: Combine the two sets of three-phase ABC signals obtained in Step 2 to obtain a three-phase ABC signal with less harmonic content and containing position information, which can significantly weaken the DC and even harmonics such as the second and fourth harmonics. The numerical value of the voltage signal obtained by superimposing A1 and A2 is used as phase A, the numerical value of the voltage signal obtained by superimposing B1 and B2 is used as phase B, and the numerical value of the voltage signal obtained by superimposing C1 and C2 is used as phase C.

[0074] Step 4: Apply the 3s / 2s (Clarke) transformation to the three-phase ABC voltage signal with harmonics obtained in Step 3 to obtain the voltage u α and u β .

[0075] Step 5: Use an optimized adaptive complex filter algorithm to filter the harmonics-containing voltages u α and u β obtained in Step 4, extract the positive-sequence voltages and and then use a phase-locked loop decoding algorithm for position calculation, so as to realize the full-speed position detection and tracking of the linear motor.

[0076] Mathematical model expression of the complex filter

[0077]

[0078] This patent gives the mathematical model expression of the adaptive complex filter

[0079]

[0080] where a ≤ n, a ∈ N + , i ∈ N + , n ∈ N + , ω^ is the output angular velocity of the phase-locked loop

[0081] For the harmonic order, the mathematical model expressions of the fundamental positive-sequence voltage, fundamental negative-sequence voltage, fifth-harmonic positive-sequence voltage, and fifth-harmonic negative-sequence voltage are given below.

[0082]

[0083] Example 1:

[0084] In the secondary-segmented primary permanent magnet linear motor of this embodiment, n = 1, m = 3, j = 1, where n is the number of motor units, m is the number of motor phases, and j is the number of pairs of armature windings 111 connected in series in a single motor unit. The motor diagram is as Figure 3 (a) shown.

[0085] The block diagram of the vector control system of the primary permanent magnet linear motor based on linear Hall position detection is as Figure 1 shown. A linear Hall position sensor is installed on the primary permanent magnet linear motor. The voltage signal containing position information obtained through the linear Hall sensor 2 is fed into a phase-locked loop with a filtering effect for position calculation to obtain speed and phase angle information, and then fed into the motor vector control block to achieve closed-loop control of the current loop, speed loop, and position loop of the motor, improving the rapidity, stability, and accuracy of the system response.

[0086] The installation method of the primary embedded linear Hall 2 within the same group is as Figure 2 shown. Four installation methods of the primary embedded linear Hall 2 within the same group are given in the present invention. The three linear Halls within the same group are respectively numbered D1, D2, and D3. Figure 2 (a) is the installation method of τ s / 6 + k×τ s where k = 0, 1, 2, 3,..., k is a natural number. The D1 encoder leads the D2 encoder by τ s / 6 + k×τ s mechanical angle, the D2 encoder leads the D3 encoder by τ s / 6 + k×τ s mechanical angle. Three encoders with such phase differences are used to construct a three-phase symmetric ABC voltage signal. The output of the D1 encoder is used as phase A, the output of the D3 encoder is used as phase B, and the output of the D2 encoder after inversion is used as phase C. Figure 2 (b) is the installation method of τ s / 3 + k×τ s where k = 0, 1, 2, 3,..., k is a natural number. The D1 encoder leads the D2 encoder by τ s / 3 + k×τ s mechanical angle, the D2 encoder leads the D3 encoder by τ s / 3 + k×τ sMechanical angle. Three encoders using this phase angle difference are used to construct a three-phase symmetric ABC voltage signal. The output of the D1 encoder is used as phase A, the output of the D2 encoder is used as phase B, and the output of the D3 encoder is used as phase C. Figure 2 In (c), it is 2×τ s / 3 + k×τ s Installation method, k = 0, 1, 2, 3, …, k is a natural number, and the D1 encoder leads the D2 encoder by 2×τ s / 3 + k×τ s Mechanical angle, the D2 encoder leads the D3 encoder by 2×τ s / 3 + k×τ s Mechanical angle. Three encoders using this phase angle difference are used to construct a three-phase symmetric ABC voltage signal. The output of the D1 encoder is used as phase A, the output of the D3 encoder is used as phase B, and the output of the D2 encoder is used as phase C. Figure 2 In (d), it is 5×τ s / 6 + k×τ s Installation method, k = 0, 1, 2, 3, …, k is a natural number, and the D1 encoder leads the D2 encoder by 5×τ s / 6 + k×τ s Mechanical angle, the D2 encoder leads the D3 encoder by 5×τ s / 6 + k×τ s Mechanical angle. Three encoders using this phase angle difference are used to construct a three-phase symmetric ABC voltage signal. The output of the D1 encoder is used as phase A, the output of the D2 encoder after inversion is used as phase B, and the output of the D3 encoder is used as phase C. When selecting the motor installation method, it is preferred to select τ that does not require an inversion operation s / 3 + k×τs installation method and 2×τ s / 3 + k×τ s Installation method, k = 0, 1, 2, 3, … k is a natural number.

[0087] To better understand the slot installation method of the secondary-segmented primary permanent magnet linear motor with a primary embedded linear Hall, an overview of the basic structure of the secondary-segmented primary permanent magnet linear motor is given. As Figure 3 shown, τ p is the primary pole pitch, τ s is the secondary pole pitch, g is the air gap height between the primary and secondary, and the quantitative relationship 2×τ p = 7×τ s / 6. The secondary-segmented primary permanent magnet linear motor has a simple structure. The secondary has no yoke and is only composed of segmented magnetic conduction blocks, using less magnetic conduction material and having a lower manufacturing cost, making it more suitable for long-distance industrial systems. The primary consists of primary magnetic conduction teeth 110, permanent magnets 112, and armature windings 111. The permanent magnets 112 are placed at the bottom of the magnetic conduction teeth 110, with the magnetization direction parallel to the center line of the magnetic conduction teeth 110. There is a magnetic conduction tooth wound with an armature winding 111 between adjacent permanent magnets 112, and the magnetization directions are opposite. The primary 11 of the secondary-segmented primary permanent magnet linear motor is arranged in the way of "primary magnetic conduction tooth with S-pole permanent magnet - magnetic conduction tooth wound with armature winding - primary magnetic conduction tooth with N-pole permanent magnet - magnetic conduction tooth wound with armature winding - primary magnetic conduction tooth with S-pole permanent magnet". The A phase of the secondary-segmented primary permanent magnet linear motor is composed of the superposition of A1 winding and A2 winding. The midlines of the A1 winding and the A2 winding are 3.5 secondary pole pitches apart. When the midline of the A1 winding is aligned with the midline of the secondary magnetic conduction tooth, the midline of the A2 winding is aligned with the midline between two secondary magnetic conduction teeth. When the primary mover of this motor moves a distance of one secondary pole pitch, the armature winding goes through a complete electrical cycle. Therefore, the A1 winding and the A2 winding are half an electrical cycle apart in space. After superimposing the back electromotive force of the A1 winding and the no-load back electromotive force of the A2 winding, the obtained no-load back electromotive force waveform has a higher sinusoidality. Figure 4 is the no-load back electromotive force waveform.

[0088] Figure 5 is the slot installation position diagram of this secondary-segmented primary permanent magnet linear motor. As can be seen from the figure, the four installation methods of the primary embedded linear Hall 2 are shown in the table in the figure. From Figure 3 it can be known that 2×τ p =7×τ s / 6, so the A1 armature teeth and the B1 armature teeth are 7×τ s / 6 mechanical distance apart. For this secondary-segmented primary permanent magnet linear motor, the installation method of τ s / 3 + k×τ s is adopted, where k = 0, 1, 2, 3,... k is a natural number. Combining with the installation method of the linear Hall 2 of the present invention, the number of motor units n = 1, the number of motor phases m = 3, and the number of pairs of armature windings 111 connected in series in a single phase in one motor unit j = 1. At this time, a total of 2*j*m = 2*3 = 6 linear Hall elements 2 can be used for position detection.

[0089] When the motor is running under no-load conditions, the source of the magnetic field at the linear Hall element is only the permanent magnet 112. Combining with the installation method of the embedded linear Hall 2, the radial magnetic density waveform and the FFT waveform are obtained by simulation, as shown in Figure 6 (a) and Figure 6 (b).

[0090] When the motor is operating under rated conditions, compared with no-load operation, the energized armature winding 111 will affect the magnetic field at the linear Hall element 2. As Figure 7 (a) and Figure 7 (b) shown.

[0091] As Figure 8 shown, after the voltage signals detected by the six linear Hall elements 2 are processed by signal filtering and superimposed by the A / D conversion module, a three-phase voltage signal U mainly containing odd harmonics is obtained A 、U B 、U C . Then, through the 3s / 2s (Clarke) transformation, the harmonic-containing voltage signals U α and U β in the two-phase stationary coordinate system are obtained. Then, the positive-sequence voltage signal is extracted through an adaptive complex filter, and finally the primary mover position information is obtained through the phase-locked loop position calculation.

[0092] Mathematical model expression of the adaptive complex filter

[0093]

[0094] where a ≤ n, a ∈ N + , i ∈ N + , n ∈ N + , w^ is the output angular velocity of the phase-locked loop

[0095] For the harmonic order, the mathematical model expressions of the fundamental positive-sequence voltage, fundamental negative-sequence voltage, fifth-harmonic positive-sequence voltage, and fifth-harmonic negative-sequence voltage are given below

[0096]

[0097] Finally, a phase-locked loop with an adaptive filtering algorithm is used to perform position tracking on the secondary-segmented primary permanent magnet linear motor. The motor accelerates uniformly to the rated speed within 0.1 s and then operates at the rated speed all the time. Figure 9 is the phase tracking diagram for the variable-speed operation of the secondary-segmented primary permanent magnet linear motor. As can be seen from the figure, for the two common operating states of this motor, no-load and rated-load operation, the phase error does not exceed 10°, and accurate and fast position tracking can be performed.

[0098] Embodiment 2:

[0099] In the secondary-segmented primary permanent magnet linear motor of this embodiment, n = 2, m = 3, j = 1, where n is the number of motor units, m is the number of motor phases, and j is the number of pairs of armature windings 111 connected in series in a single motor unit. The motor diagram is as Figure 3 (b) shown.

[0100] The position detection of this motor still uses Figure 1 the overall control block diagram. A linear Hall position sensor 2 is installed on the linear motor, and the voltage signal containing position information obtained through the linear Hall sensor 2 is passed into a phase-locked loop with a filtering effect for position calculation to obtain speed and phase angle information, and then passed into the motor vector control block to achieve closed-loop control of the current loop, speed loop, and position loop of the motor, improving the rapidity, stability, and accuracy of the system response.

[0101] The structure of this secondary-segmented primary permanent magnet linear motor is as shown in Figure 3 (b). It belongs to a type of secondary-segmented primary permanent magnet linear motor. The working principle and working characteristics of the secondary-segmented primary permanent magnet linear motor have been introduced in detail in Embodiment 1 and will not be introduced here. Using Figure 2 the τ s / 3 + k×τ s Hall installation method, where k = 0, 1, 2, 3,... k is a natural number. The slot installation position of this secondary-segmented primary permanent magnet linear motor is as shown in Figure 10 shown,

[0102] Combined with the installation method of the linear Hall 2 of the present invention, the number of motor units n = 2, the number of motor phases m = 3, and the number of pairs of armature windings 111 connected in series in a single phase in a motor unit j = 1. At this time, a total of 2*j*m = 2*3 linear Hall elements 2 can be used for position detection. Considering the structural characteristics of this motor, there are a total of 2mnj = 12 primary 10 slots in this motor where linear Hall elements 2 can be installed. Considering the end effect of the linear motor and the cost impact of the position detection device, combined with the air-gap magnetic density waveform of the linear Hall elements 2 in 12 slots, 2*j*m = 2*3 = 6 linear Hall elements 2 are selected to extract a voltage signal containing position information with better sinusoidality.

[0103] The waveform diagram and FFT diagram of the superimposed air-gap radial magnetic density extracted when this motor runs without load are as shown in Figure 11 shown, and the waveform diagram and FFT diagram of the superimposed air-gap radial magnetic density extracted when running under the rated load state are as shown in Figure 12 shown. From the FFT graph, it can be seen that through the linear Hall installation method proposed in this patent, the even harmonics in the position detection signal can be well weakened. After passing through a complex filter for filtering odd harmonics, the phase can be tracked quickly and accurately.

[0104] Figure 13 is the position tracking phase diagram of this secondary-segmented primary permanent magnet linear motor. This motor accelerates uniformly to the rated speed within 0.2 s and then runs at the rated speed all the time. From Figure 13 it can be known that for the two typical operating states of the motor, position tracking detection in the full speed range of this motor can be achieved.

[0105] Embodiment 3:

[0106] In the secondary-segmented primary permanent magnet linear motor of this embodiment, n = 3, m = 3, j = 1, where n is the number of motor units, m is the number of motor phases, and j is the number of pairs of armature windings 111 connected in series in a single phase in one motor unit.

[0107] For the position detection of this secondary-segmented primary permanent magnet linear motor, the Figure 1 overall control block diagram is still used. According to the Hall installation method proposed by the present invention, the slot installation positions of the linear Hall-based secondary-segmented primary permanent magnet linear motor are as shown in Figure 14 . Combining with the installation method of the linear Hall 2 of the present invention, with the number of motor units n = 3, the number of motor phases m = 3, and the number of pairs of armature windings 111 connected in series in a single phase in one motor unit j = 1, at this time, a total of 2*j*m = 2*3 linear Hall elements 2 can be used for position detection. Considering the structural characteristics of this motor, there are a total of 2mnj = 18 primary 10 slots where the linear Hall elements 2 can be installed. Considering the end effect of the linear motor and the cost impact of the position detection device, combining the air-gap magnetic density waveforms of the linear Hall elements 2 in the 18 slots, 2*j*m = 2*3 = 6 linear Hall elements 2 are selected. The harmonics of the radial air-gap magnetic density at the installation positions of these six linear Hall 2 are the least, and a voltage signal with better sinusoidality and containing position information is extracted from them. Then, through the Figure 8 algorithm calculation, the position tracking of this linear motor can be accurately and quickly carried out. Figure 15 is the estimated value of the primary angle obtained by calculation.

[0108] Embodiment 4:

[0109] In the secondary-segmented primary permanent magnet linear motor of this embodiment, n = 4, m = 3, j = 1, where n is the number of motor units, m is the number of motor phases, and j is the number of pairs of armature windings 111 connected in series in a single phase in one motor unit.

[0110] Based on the linear Hall, the slot installation positions of the secondary-segmented primary permanent magnet linear motor are as shown in Figure 16 . Combining with the structure of this primary permanent magnet linear motor, according to the position detection method of the present invention, which has been introduced in detail above and will not be elaborated here, there are a total of 2mnj = 24 primary 10 slots where the linear Hall elements 2 can be installed in this motor. 2*j*m = 2*3 linear Hall elements 2 are selected for position detection. The harmonics of the radial air-gap magnetic density at the installation positions of these six linear Hall 2 are the least, and a voltage signal with better sinusoidality and containing position information is extracted from them. Then, through the Figure 8 algorithm calculation, the position tracking of this linear motor can be accurately and quickly carried out. Figure 17 is the estimated value of the primary angle obtained by calculation.

[0111] As can be seen from the above content, for the linear Hall position detection method of the secondary segmented primary permanent magnet linear motor proposed by the present invention, without changing the structure of the linear motor, by combining the magnetic field characteristics of the linear motor and using 2j groups of linear Hall elements in combination, the sinusoidality of the collected voltage signal is improved. In addition, the phase-locked loop algorithm with a complex filter proposed by the present invention is used for position calculation, which improves the accuracy and rapidity of position tracking.

[0112] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and the description in the specification only illustrate the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of the present invention claimed is defined by the appended claims and their equivalents.

Claims

1. Secondary segmented primary permanent magnet linear motor, characterized in that, The linear motor includes a primary (11) and a secondary (10). Both the primary (11) and the secondary (10) are made of magnetically permeable materials and there is an air gap between them. The primary (11) is provided with magnetically permeable teeth (110). Armature windings (111) and permanent magnets (112) are alternately arranged on the magnetically permeable teeth (110). The permanent magnets (112) are placed at the bottom of the magnetically permeable teeth (110). Adjacent permanent magnets (112) are separated by two primary pole pitches and have opposite magnetization directions. The magnetically permeable teeth (110) on which the armature windings (111) are placed are called armature winding magnetically permeable teeth, and the magnetically permeable teeth (110) on which the permanent magnets (112) are placed are called permanent magnet magnetically permeable teeth. A linear Hall element (2) for motor position detection is embedded in the primary slot where the armature winding (111) is placed between the permanent magnet magnetically permeable teeth and the armature winding magnetically permeable teeth. The linear Hall element (2) remains relatively stationary with the primary (11) of the linear motor and moves synchronously.

2. The secondary segmented primary permanent magnet linear motor according to claim 1, wherein The number of the magnetic teeth (110) of the primary (11) of the linear motor is 4mnj+1, and the distance between the center lines of two adjacent magnetic teeth (110) is the primary pole pitch τ. p The magnetic teeth (110) are provided with 2mnj armature windings (111) and 2mnj+1 permanent magnets (112); the secondary (10) is provided with segmented magnetic blocks, and the center line distance between two adjacent segmented magnetic blocks is the secondary pole pitch τ s ; The primary pole pitch satisfies the following formula: The linear motor is composed of n motor units, where L ef is defined as a motor unit. Each motor unit consists of 2mj permanent magnet magnetic teeth and 2mj armature winding magnetic teeth. Any one-phase armature winding in the motor unit is composed of j pairs of armature windings (111) connected in series. Starting from the first armature winding (111), there are j armature windings (111) placed on adjacent armature winding magnetic teeth that belong to the same phase. Subsequently, j armature windings (111) of adjacent phases are arranged in sequence on the armature winding magnetic teeth. According to the above arrangement, 2*j armature windings (111) belonging to the same phase form j pairs of complementary armature windings, and the relative positions of the two armature windings (111) in any pair of armature windings differ by half a secondary pole pitch from the secondary (10); where τ p is the primary pole pitch, τ s is the secondary pole pitch, m is the number of phases of the motor, n is the number of motor units, j is the number of pairs of armature windings (111) connected in series for a single phase in a motor unit, and q is the number of armature windings connected in series for a single phase in a motor unit.

3. The secondary segmented primary permanent magnet linear motor according to claim 2, wherein There are 2*j groups of linear Hall elements (2) in the linear motor. Each group of linear Hall elements contains m linear Hall elements (2), that is, a total of 2*j*m linear Hall elements 2 are installed. The outputs of the m linear Hall elements (2) in each group are m-phase position information. The position information of any phase of the linear motor is composed of the superposition of the outputs of j pairs of linear Hall elements (2). Starting from the first linear Hall element (2), there are j linearly Hall elements (2) placed in adjacent positions that belong to the same phase. Subsequently, j linearly Hall elements (2) belonging to adjacent phases are arranged in sequence. According to the above arrangement, 2*j linearly Hall elements (2) belonging to the same phase form j pairs of complementary linear Hall elements, and the interval between the two linear Hall elements (2) in any pair of linear Hall elements is (2k + 1)×0.5×τ s , where k = 0, 1, 2, 3,..., and k is a natural number.

4. A position detection method, characterized in that, The position detection method is based on the secondary-segmented primary permanent magnet linear motor as described in claim 1, and is characterized by including the following specific steps: Step 1: Select linear Hall elements, with m in each group. According to the number of pairs of armature windings connected in series in a single phase of a motor unit, they are divided into 2*j groups and installed at the set positions of the primary (11) slots between the permanent magnet magnetically permeable teeth and the armature winding magnetically permeable teeth. The linear Hall elements (2) convert the magnetic signals at the specified positions into electrical signals. Step 2: Combine the m-phase electrical signals obtained in Step 1 to obtain an m-phase voltage signal containing position information with less harmonic content. Step 3: The m-phase voltage signal containing harmonics obtained in Step 2 is subjected to Clarke transformation to obtain the harmonics-containing voltages u α and u β ; Step 4: Use the optimized adaptive complex filtering algorithm to filter the voltage u α and u β to extract the positive-sequence voltage and Then use the phase-locked loop decoding algorithm for position calculation, so as to realize the position detection and tracking of the linear motor in the full-speed range.

5. The position detection method according to claim 4, characterized in that The set positions of the primary (11) slots between the permanent magnet magnetically permeable teeth and the armature winding magnetically permeable teeth are: 2*j linear Hall elements (2) belonging to the same phase form j pairs of complementary linear Hall elements, and the distance between two linear Hall elements (2) in any pair of linear Halls is (2k + 1) × 0.5 × τ s , where k = 0, 1, 2, 3,..., and k is a natural number.

6. The position detection method according to claim 4, characterized in that In Step 1, the electrical signals are named. The first group is named A1, B1, C1... m1, the second group is named A2, B2, C2... m2, m is the number of phases of the motor, and there are 2*j groups in total, and so on. The numerical value of the voltage signal obtained by superimposing A1 and A2... Aq is used as the A phase, the numerical value of the voltage signal obtained by superimposing B1 and B2... Bq is used as the B phase, the numerical value of the voltage signal obtained by superimposing C1 and C2... Cq is used as the C phase, and so on, that is, an m-phase voltage signal containing harmonics.

7. The position detection method according to any one of claims 4 to 6, characterized in that The number of pairs j ∈ N of the armature windings (111) connected in series in a single phase in said one motor unit + .

8. The position detection method according to claim 7, characterized in that, The installation method of the set positions of the primary (11) slots installed between the permanent magnet magnetically permeable teeth and the armature winding magnetically permeable teeth is as follows: (1) Installation method of linear Hall sensors in the same group: m linear Hall sensors in the same group construct m symmetrical voltage signals, and the mechanical distance between adjacent linear Hall elements of an m-phase motor is 2*τ p , where in a secondary-segmented primary permanent magnet linear motor, τ p is the primary pole pitch, and τ s is the secondary pole pitch. For a common three-phase motor, the installation methods using τ s / 3 + k×τ s , τ s / 6 + k×τ s , 2×τ s / 3 + k×τ s , 5×τ s / 6 + k×τ s are adopted, where k = 0, 1, 2, 3,... and k is a natural number. Four different installation methods can be transformed into standard three-phase signals; (2) Installation method of linear Hall elements in different groups: 2*j linear Hall elements (2) belonging to the same phase form j pairs of complementary linear Hall elements, and the distance between two linear Hall elements (2) in any pair of linear Hall elements is (2k + 1)×0.5×τ s , where k = 0, 1, 2, 3,..., k is a natural number, and the installation positions of 2*j*m linear Hall elements (2) do not coincide.

9. The position detection method according to claim 7, characterized in that In Step 4, the mathematical model expression of the adaptive complex filter is as follows: where a ≤ n, a ∈ N + , i ∈ N + , n ∈ N + , where w^ is the output angular velocity of the phase-locked loop, ω c is the cut-off frequency, is the positive sequence component of the i-th harmonic, is the negative sequence component of the i-th harmonic, U αβ (s) is the total voltage component containing harmonics.

Images