A permanent magnet arrangement method for a motor

Abstract

The present application discloses a method for arranging permanent magnets of a motor, and proposes a sinusoidal magnetic field pulse width modulation SFPWM theory, which is used to design a permanent magnet array of a motor, so that the change of the magnetic induction intensity of the permanent magnet array of the motor in the spatial magnetic field along the direction of motion approaches a sine curve, and the magnets in the permanent magnet array of the motor are one or more pieces, which reduces the amount of magnets used in motors of the same capacity. The method for arranging permanent magnets of a motor includes: proposing a sinusoidal magnetic field pulse width modulation SFPWM theory to design the number of magnets, the size of magnets, and the arrangement position of magnets in the permanent magnet array of the motor, wherein the number of magnets is an odd number greater than or equal to 1; setting corresponding magnets according to the arrangement position of the magnets to form a permanent magnet array of the motor, and finally forming a motor pole.

Description

Technical Field

[0001] The invention relates to the application field of permanent magnet motors, and in particular to a method for arranging permanent magnets of motors. Background Art

[0002] my country has listed internal combustion engine hybrid power, hybrid trains, high-speed maglev trains, ship power integrated systems and electric propulsion systems, hybrid electric aircraft and pure electric aircraft as key scientific research directions, providing significant demand for the in-depth utilization of motors.

[0003] Traditional permanent magnet rotary motors or linear motors use permanent magnet N-pole and S-pole arrangement, which are usually composed of several permanent magnet monomers of the same specifications arranged along the circumference or in parallel to form a motor permanent magnet array. In the array, the polarity of all permanent magnet monomers is arranged alternately with N-pole and S-pole. The permanent magnet array with this structural arrangement has a large spatial magnetic field distortion rate, poor motor performance, high harmonic content, and large additional motor losses, which increases the difficulty of motor control.

[0004] The Chinese patent application number 202010552909.3 proposes a new type of permanent magnet arrangement structure. Compared with the existing permanent magnet arrangement, when using the same number of permanent magnet monomers, the magnetic field magnetic induction intensity at the middle position between the bilateral permanent magnets can be greater, and the change trend of the magnetic induction intensity at the middle position between the bilateral permanent magnets along the arrangement direction of the permanent magnet monomers is closer to a sine curve.

[0005] The Halbach permanent magnet array, which has been gaining increasing attention in the field of permanent magnet motor applications, originated from the patent "An improved box for containing powder for toilet and other purposes" published in 1943. It solved the problem of efficient use of the magnetic field on one side, and was able to strengthen the magnetic induction intensity of the spatial magnetic field on one side and weaken the magnetic field distribution on the opposite side. However, it cannot best form the sinusoidal magnetic field distribution required by an ideal motor. Summary of the invention

[0006] The purpose of the present invention is to provide a method for arranging permanent magnets of a motor and propose a sinusoidal magnetic field pulse width modulation SFPWM theory for designing a permanent magnet array of a motor so that the change in the magnetic induction intensity of the spatial magnetic field of the permanent magnet array of the motor along the direction of movement approaches a sine curve. The magnetic steel in the permanent magnet array of the motor is one or more pieces, thereby reducing the amount of magnetic steel used in motors of the same capacity.

[0007] A first aspect of the present invention provides a method for arranging permanent magnets of a motor, comprising:

[0008] The sinusoidal magnetic field pulse width modulation SFPWM theory is proposed to design the number, size and arrangement of magnets in the permanent magnet array of the motor. The number of magnets is an odd number greater than or equal to 1.

[0009] The corresponding magnetic steel is set according to the arrangement position of the magnetic steel to form a permanent magnet array of the motor, and finally form the motor poles.

[0010] Furthermore, the sinusoidal magnetic field pulse width modulation SFPWM theory is proposed to design the number, size and arrangement of the magnets in the permanent magnet array of the motor, including:

[0011] According to the sinusoidal magnetic field pulse width modulation SFPWM theory, the sinusoidal magnetic field, sinusoidal demand, pulse width demand and modulation mode of the motor permanent magnet array are determined. The sinusoidal magnetic field is half a cycle.

[0012] The number of magnets in the permanent magnet array of the motor is set according to the sinusoidal curve requirement, and the number of magnets is an odd number greater than or equal to 1;

[0013] Set the magnet size of the corresponding magnet according to the pulse width requirement;

[0014] The magnetic steel arrangement position of each magnetic steel is set according to the modulation mode.

[0015] Further, the magnetic steel arrangement position of each magnetic steel is set according to the modulation mode, including:

[0016] According to the number and size of magnetic steels, the sinusoidal magnetic field is divided into magnetic field zones, and each magnetic field zone corresponds to a magnetic steel;

[0017] According to the modulation mode, the magnetic steel center line of each magnetic steel is overlapped with the magnetic field gravity center line of the corresponding magnetic field area to obtain the magnetic steel arrangement position of each magnetic steel.

[0018] Further, the magnetic steel arrangement position of each magnetic steel is set according to the modulation mode, including:

[0019] According to the number and size of magnetic steels, the sinusoidal magnetic field is divided into magnetic field zones, and each magnetic field zone corresponds to a magnetic steel;

[0020] According to the modulation mode, the magnetic steel center line of each magnetic steel is overlapped with the magnetic field center line of the corresponding magnetic field zone to obtain the magnetic steel arrangement position of each magnetic steel.

[0021] Furthermore, when the number of magnetic steels is equal to 1, the sinusoidal magnetic field is a magnetic field region, and the magnetic field center line of the magnetic field region coincides with the magnetic field gravity center line.

[0022] Furthermore, when the number of magnets is an odd number greater than 1, the magnets include a central magnet and multiple pairs of symmetrical magnets symmetrical about the magnetic center line of the central magnet, the magnet sizes of the same pair of symmetrical magnets are the same, and the magnet sizes of all symmetrical magnets and the central magnet are the same or different.

[0023] It can be seen that in the motor permanent magnet arrangement method of the present invention, the sinusoidal magnetic field pulse width modulation SFPWM theory is proposed to design the number of magnets, magnet size and magnet arrangement position of the magnets in the motor permanent magnet array. The number of magnets is an odd number greater than or equal to 1. The corresponding magnets are arranged according to the magnet arrangement position to form the motor permanent magnet array, and finally the motor poles are formed. The sinusoidal magnetic field pulse width modulation SFPWM theory is proposed to design the motor permanent magnet array, so that the change of the magnetic induction intensity of the motor permanent magnet array in the space magnetic field along the direction of movement approaches a sine curve. The magnets in the motor permanent magnet array are one or more pieces, which reduces the amount of magnets used in motors of the same capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 A schematic diagram of a flow chart of an embodiment of a method for arranging permanent magnets of a motor provided by the present invention;

[0026] Figure 2 A schematic diagram of a permanent magnet array of a motor composed of one magnetic steel provided by the present invention;

[0027] Figure 3 A schematic diagram of an arrangement of three magnets provided by the present invention to form a motor permanent magnet array with coincident gravity center lines;

[0028] Figure 4 A schematic diagram of an arrangement of three magnetic steels provided by the present invention to form a permanent magnet array of a motor with overlapping center lines;

[0029] Figure 5 A schematic diagram of an arrangement of five magnets provided by the present invention to form a motor permanent magnet array with coincident gravity center lines;

[0030] Figure 6 A schematic diagram of an arrangement of five magnets provided by the present invention to form a permanent magnet array of a motor with overlapping center lines. DETAILED DESCRIPTION

[0031] The present application discloses a method for arranging permanent magnets of a motor and proposes a sinusoidal magnetic field pulse width modulation (SFPWM) theory for designing a permanent magnet array of a motor so that the change in magnetic induction intensity of the spatial magnetic field of the permanent magnet array of the motor along the direction of motion approaches a sine curve. The permanent magnet array of the motor has one or more magnets, thereby reducing the amount of magnets used in motors of the same capacity.

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0034] In addition, in the present invention, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0035] In the present invention, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0036] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0037] Please refer to Figure 1 , an embodiment of the present invention provides a method for arranging permanent magnets of a motor, comprising:

[0038] 101. Propose the sinusoidal magnetic field pulse width modulation SFPWM theory, design the number of magnets, magnet size and magnet arrangement position of the permanent magnet array of the motor, and the number of magnets is an odd number greater than or equal to 1;

[0039] 102. According to the arrangement positions of the magnetic steels, corresponding magnetic steels are arranged to form a permanent magnet array of the motor, and finally form the magnetic poles of the motor.

[0040] In the embodiment of the present invention, sinusoidal field pulse width modulation (SFPWM) draws on the idea of ​​sinusoidal space vector pulse width modulation (SVPWM) in the motor control method. It can be understood that SFPWM takes the sinusoidal magnetic field as the target, and realizes the sinusoidal distribution of the spatial magnetic field amplitude along the motion path by designing the number, size and arrangement position of the motor permanent magnets. Among them, the pulse width corresponds to the magnet size, modulation refers to the arrangement, and the actual meaning of SFPWM refers to the arrangement of the sinusoidal magnetic field magnets. SVPWM uses the ideal magnetic flux circle of the stator of a three-phase symmetrical motor when powered by a three-phase symmetrical sinusoidal wave voltage as a reference standard, and appropriately switches the different switching modes of the three-phase inverter to form a PWM wave, and uses the actual magnetic flux vector formed to track its accurate magnetic flux circle. Therefore, a sinusoidal magnetic field pulse width modulation (SFPWM) theory is proposed to design the permanent magnet array of the motor, so that the change of the magnetic induction intensity of the spatial magnetic field of the permanent magnet array of the motor along the direction of movement approaches a sine curve, and the magnetic steel in the permanent magnet array of the motor can be an odd number greater than or equal to 1, reducing the amount of magnetic steel used in motors of the same capacity.

[0041] Optionally, in some embodiments of the present invention, a sinusoidal magnetic field pulse width modulation SFPWM theory is proposed to design the number of magnetic steels, the size of magnetic steels and the arrangement position of magnetic steels in the permanent magnet array of the motor, including:

[0042] According to the sinusoidal magnetic field pulse width modulation SFPWM theory, the sinusoidal magnetic field, sinusoidal demand, pulse width demand and modulation mode of the motor permanent magnet array are determined. The sinusoidal magnetic field is half a cycle.

[0043] The number of magnets in the permanent magnet array of the motor is set according to the sinusoidal curve requirement, and the number of magnets is an odd number greater than or equal to 1;

[0044] Set the magnet size of the corresponding magnet according to the pulse width requirement;

[0045] The magnetic steel arrangement position of each magnetic steel is set according to the modulation mode.

[0046] Optionally, in some embodiments of the present invention, the magnetic steel arrangement position of each magnetic steel is set according to the modulation mode, including:

[0047] According to the number and size of magnetic steels, the sinusoidal magnetic field is divided into magnetic field zones, and each magnetic field zone corresponds to a magnetic steel;

[0048] According to the modulation mode, the magnetic steel center line of each magnetic steel is overlapped with the magnetic field gravity center line of the corresponding magnetic field area to obtain the magnetic steel arrangement position of each magnetic steel.

[0049] Optionally, in some embodiments of the present invention, the magnetic steel arrangement position of each magnetic steel is set according to the modulation mode, including:

[0050] According to the number and size of magnetic steels, the sinusoidal magnetic field is divided into magnetic field zones, and each magnetic field zone corresponds to a magnetic steel;

[0051] According to the modulation mode, the magnetic steel center line of each magnetic steel is overlapped with the magnetic field center line of the corresponding magnetic field zone to obtain the magnetic steel arrangement position of each magnetic steel.

[0052] Optionally, in some embodiments of the present invention, when the number of magnetic steels is equal to 1, the sinusoidal magnetic field is a magnetic field zone, and the magnetic field center line of the magnetic field zone coincides with the magnetic field gravity center line.

[0053] Optionally, in some embodiments of the present invention, when the number of magnets is an odd number greater than 1, the magnets include a central magnet, and multiple pairs of symmetrical magnets symmetrical about the magnetic center line of the central magnet, the magnet sizes of the same pair of symmetrical magnets are the same, and the magnet sizes of all symmetrical magnets and the magnetic size of the central magnet are the same or different.

[0054] The above embodiments are described in detail below with reference to examples. Figure 2 The figure shows a schematic diagram of a permanent magnet array of a motor composed of one magnetic steel, that is, the polarity of the single magnetic pole of the traditional permanent magnet is alternating between N pole and S pole, and the area of ​​the half-cycle sine curve (i.e. S area) is equal to the rectangular area of ​​the 1# magnetic pole. Among them, the left rectangle represents the magnetic field magnetic induction intensity distribution of the N pole on the motion path, the right rectangle represents the magnetic field magnetic induction intensity distribution of the S pole on the spatial motion path, and the sine curve represents the ideal spatial fundamental wave distribution magnetic field generated by the N pole and S pole magnets.

[0055] Since the 1# permanent magnet array and the 2# permanent magnet array are axially symmetrical figures about the middle vertical dotted line, the arrangement and setting of the 1# permanent magnet array will be taken as an example for description below.

[0056] Figure 2 The vertical dotted line 1 in shows the centroid and center line of the 1# permanent magnet array and the half-cycle sinusoidal curve.

[0057] like Figure 3 As shown, the motor permanent magnet array is composed of 3 magnetic steels, and the center of gravity lines are arranged to coincide. Figure 32 in the middle is the center of gravity and center line of S1 area, 3 is the center of gravity of S2 area, the 3 rectangles on the left represent 3 pairs of NS pole magnets, arranged in the form of axisymmetry with the center line 2 on the left, and the horizontal symmetry line of each rectangular monomer is the center line of the monomer N pole; the half cycle of the sine curve is divided into three parts, namely 1 S1 area and 2 S2 areas, the widths of the 2 S2 areas are equal, the widths of S1 area and S2 area can be equal or unequal, and each part is calculated to obtain a vertical line that divides its area equally, and this line is the center of gravity. The magnet is installed at the position where the center of gravity coincides.

[0058] like Figure 4 As shown, the motor permanent magnet array is composed of 3 magnetic steels, and the arrangement is such that the center lines coincide. Figure 4 4 in the middle is the center of gravity and center line of S1 area, 5 is the center line of S2 area, and the 3 rectangles on the left represent 3 pairs of NS pole magnets, which are arranged in the form of axisymmetry with the center line 4 on the left side. The horizontal symmetry line of each rectangular monomer is the center line of the monomer N pole; the half cycle of the sine curve is divided into three parts, namely 1 S1 area and 2 S2 areas. The widths of the 2 S2 areas are equal. The widths of S1 area and S2 area can be equal or unequal. The vertical line drawn from the midpoint of the corresponding width of each part is the center line. The magnet is installed at the position where the center line coincides.

[0059] like Figure 5 As shown, the motor permanent magnet array is composed of 5 magnetic steels, and the center of gravity lines are arranged in a coincident manner. Figure 5 6 is the center of gravity and center line of S1 area, 7 is the center of gravity of S2 area, 8 is the center of gravity of S3 area, and the 5 rectangles on the left represent 5 pairs of NS pole magnets, which are arranged in the form of axisymmetry with the center line 6 on the left side, and the horizontal symmetry line of each rectangular monomer is the center line of the monomer N pole; the half cycle of the sine curve is divided into five parts, namely 1 S1 area, 2 S2 areas and 2 S3 areas, the widths of the 2 S2 areas are equal, the widths of the 2 S3 areas are equal, and the widths of S1, S2 and S3 areas can be equal or unequal. Each part is calculated to obtain a vertical line that divides its area equally, and this line is the center of gravity. The magnet is installed at the position where the center of gravity lines coincide.

[0060] like Figure 6 As shown, the motor permanent magnet array is composed of 5 magnetic steels, and the arrangement is such that the center lines coincide. Figure 69 is the center of gravity and center line of S1 area, 10 is the center line of S2 area, 11 is the center line of S3 area, and the 5 rectangles on the left represent 5 pairs of NS pole magnets, which are arranged in the form of axisymmetry with the center line 9 on the left side. The horizontal symmetry line of each rectangular monomer is the center line of the monomer N pole; the half cycle of the sine curve is divided into five parts, namely 1 S1 area, 2 S2 areas and 2 S3 areas. The widths of the 2 S2 areas are equal, and the widths of the 2 S3 areas are equal. The widths of S1, S2 and S3 areas can be equal or unequal. The vertical line drawn from the midpoint of the corresponding width of each part is the center line. The magnet is installed at the position where the center line coincides.

[0061] Through the above embodiments, the sinusoidal distribution of the magnetic field magnetic induction intensity of the motor permanent magnet array on the moving path is significantly better than the traditional alternating arrangement of N poles and S poles.

[0062] The advantage of the permanent magnet arrangement method proposed in the present invention is that it can not only achieve the sinusoidal distribution of the magnetic induction intensity of the spatial magnetic field of the motor permanent magnet array, but also improve the utilization efficiency of the permanent magnets. In theory, it can form an approximately sinusoidal distribution of the magnetic field of the motor permanent magnet array.

[0063] In engineering applications, considering the cost-effectiveness, the motor permanent magnet array has little practical significance if it exceeds 7 magnets. However, the motor permanent magnet arrangement method of the present invention still protects the motor permanent magnet array including 7 magnets.

[0064] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0065] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0066] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for arranging permanent magnets of a motor, It is characterized in that include: The sinusoidal magnetic field pulse width modulation SFPWM theory is proposed to design the number of magnets, magnet size and magnet arrangement position of the magnets in the permanent magnet array of the motor, wherein the number of magnets is an odd number greater than or equal to 1; According to the arrangement positions of the magnetic steels, corresponding magnetic steels are arranged to form the permanent magnet array of the motor, and finally form the magnetic poles of the motor; The proposed sinusoidal magnetic field pulse width modulation SFPWM theory designs the number, size and arrangement of magnetic steel in the permanent magnet array of the motor, including: According to the sinusoidal magnetic field pulse width modulation SFPWM theory, the sinusoidal magnetic field, sinusoidal demand, pulse width demand and modulation mode of the motor permanent magnet array are determined, wherein the sinusoidal magnetic field is half a cycle; The number of magnetic steels in the permanent magnet array of the motor is set according to the sinusoidal curve requirement, and the number of magnetic steels is an odd number greater than or equal to 1; Setting the magnetic steel size of the corresponding magnetic steel according to the pulse width requirement; Setting the magnetic steel arrangement position of each magnetic steel according to the modulation mode; The step of setting the magnetic steel arrangement position of each magnetic steel according to the modulation mode comprises: According to the number of magnetic steels and the size of the magnetic steels, the sinusoidal magnetic field is divided into magnetic field zones, each magnetic field zone corresponds to a magnetic steel; According to the modulation mode, the magnetic steel center line of each magnetic steel is overlapped with the magnetic field gravity center line of the corresponding magnetic field area to obtain the magnetic steel arrangement position of each magnetic steel; Alternatively, the step of setting the magnetic steel arrangement position of each magnetic steel according to the modulation mode includes: According to the number of magnetic steels and the size of the magnetic steels, the sinusoidal magnetic field is divided into magnetic field zones, each magnetic field zone corresponds to a magnetic steel; According to the modulation mode, the magnetic steel center line of each magnetic steel is overlapped with the magnetic field center line of the corresponding magnetic field area to obtain the magnetic steel arrangement position of each magnetic steel; When the number of the magnetic steels is an odd number greater than 1, the magnetic steels include a central magnetic steel, and multiple pairs of symmetrical magnetic steels symmetrical with the magnetic steel center line of the central magnetic steel as the axis, the magnetic steel sizes of the same pair of symmetrical magnetic steels are the same, the magnetic steel sizes of all the symmetrical magnetic steels are the same as the magnetic steel size of the central magnetic steel, or the magnetic steel sizes of all the symmetrical magnetic steels are different from the magnetic steel size of the central magnetic steel.

2. The method for arranging permanent magnets of a motor according to claim 1, It is characterized in that When the number of magnetic steels is equal to 1, the sinusoidal magnetic field is a magnetic field zone, and the magnetic field center line of the magnetic field zone coincides with the magnetic field gravity center line.

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