CN102158019B - Magnetization method and magnetization component of permanent magnet motor - Google Patents

Abstract

The invention discloses a method for magnetizing a permanent magnet motor. First, a magnetizing coil is wound on the surface of an unmagnetized permanent magnet, and then the unmagnetized permanent magnet wrapped with the magnetizing coil is placed on the motor rotor or stator, and then Assemble the stator rotor of the permanent magnet motor, charge the magnetized coil after assembly, the direction of the magnetic field generated by the coil is the same as that of the unmagnetized permanent magnet, and the unmagnetized permanent magnet is magnetized into a permanent magnet to realize the permanent magnet motor magnetization. The present invention also provides a magnetizing assembly for realizing the above method. The invention solves the difficulty of assembling the permanent magnet motor, facilitates magnetization again after the permanent magnet loses magnetism, reduces the assembly and maintenance cost of the permanent magnet motor, and reduces the capacity and volume of the required magnetizing power supply.

Description

A magnetizing method for a permanent magnet motor and a magnetizing component

technical field

The invention relates to the field of permanent magnet motors, in particular to a method for magnetizing a permanent magnet motor and a magnetizing component for realizing the method

Background technique

Compared with the traditional electric excitation motor, the permanent magnet motor has the characteristics of simple structure, reliable operation, low loss and high efficiency. The permanent magnet system of a permanent magnet motor usually includes multiple pairs of magnetic poles, each magnetic pole is formed by superimposing the magnetic field generated by one or more independent permanent magnets, and the permanent magnet is composed of a single or multiple permanent magnet blocks. The magnetization directions of different permanent magnets in the same magnetic pole can be the same or different, but the permanent magnet blocks forming the same permanent magnet have the same or nearly the same magnetization directions. For example, in Fig. 1, the permanent magnet magnet system of the permanent magnet motor has four magnetic poles 21, 22, 23, 24 located on the motor rotor 10, which are evenly distributed along the ring direction of the rotor 10 according to the sequence of N pole-S pole arrangement, each The magnetic poles are mainly formed by the superimposition of the magnetic fields generated by two independent permanent magnets, wherein the magnetic pole 21 is composed of permanent magnets 31 and 32, the magnetic pole 22 is composed of permanent magnets 32 and 33, the magnetic pole 23 is composed of permanent magnets 33 and 34, and the magnetic pole 24 is composed of permanent magnets. The magnetic fields generated by 34 and 31 are superimposed, and each permanent magnet is spliced by seven permanent magnet blocks. For example, permanent magnet 32 is spliced by permanent magnet blocks: 41, 42, 43, 44, 45, 46 and 47. become. Herein, a permanent magnet that has not been magnetized and has no magnetism is referred to as an unmagnetized permanent magnet.

The installation of permanent magnets in permanent magnet motors becomes a difficult problem due to their very strong magnetic force. At present, there are mainly two installation methods for permanent magnets in permanent magnet motors. The first method is to magnetize first, that is, to magnetize unmagnetized permanent magnets into permanent magnets, and then install the permanent magnets on the permanent magnet motor. The second is the traditional post-magnetization method, that is, firstly assemble the unmagnetized permanent magnets on the permanent magnet motor, and then use special magnetizing equipment to magnetize the unmagnetized permanent magnets in the permanent magnet motor into permanent magnets.

There are deficiencies in the above two permanent magnet installation methods.

For the first magnetization method, because the permanent magnet has a strong magnetic force, it will cause many problems: first, the assembly and positioning are difficult, the permanent magnets may attract or repel each other during the assembly, or the permanent magnet attracts the magnetic conductive parts of the permanent magnet motor , so it is difficult to assemble the permanent magnet to the predetermined position; second, it is easy to knock and damage the permanent magnet or let it irreversibly demagnetize during assembly. Once the permanent magnet is damaged, it is difficult to remove the permanent magnet from the permanent magnet and the ferromagnetic parts of the permanent magnet motor. The third is that assembly often requires the use of special tooling equipment, which complicates assembly and increases costs; fourth, permanent magnets tend to absorb ferromagnetic substances around them, and ferromagnetic substances are attracted by permanent magnets, like bullets out of the chamber, which is harmful to personal safety. pose a serious threat.

The second method - the traditional post-magnetization method also has many shortcomings. First of all, most permanent magnet motors cannot use the post-magnetization method due to the limitations of structure, volume, weight or the shielding of high magnetic permeability materials outside the permanent magnet. Even if it is possible, it is often only possible to send the part of the permanent magnet motor equipped with unmagnetized permanent magnets into the magnetizing equipment for magnetization, so it is difficult to magnetize after the stator and rotor of the permanent magnet motor are assembled. For example, for permanent magnet motors with permanent magnets on the rotor, the traditional post-magnetization method can only send the rotor equipped with unmagnetized permanent magnets to the magnetization equipment for magnetization, and cannot send the assembled motor to the magnetization equipment. In the equipment, this is because the motor casing will shield the magnetizing magnetic field and the magnetizing coil is far away from the permanent magnet, so that the permanent magnet cannot be magnetized. In addition, because the part containing the permanent magnet has a strong magnetic force, assembling the part containing the permanent magnet and the part not containing the permanent magnet in the permanent magnet motor will cause the same assembly problem as the pre-magnetization method. Secondly, due to the limitation of the structure and space of the permanent magnet motor, the magnetizing coil of the magnetizing equipment is far away from the unmagnetized permanent magnet, so it is not easy to saturate the unmagnetized permanent magnet, and the magnetizing magnetic field generated by the magnetizing equipment The direction is difficult to be consistent with the magnetization direction of the unmagnetized permanent magnet, which will result in a high price to be paid for the magnetization saturation of the unmagnetized permanent magnet. For example in Fig. 2 (a) permanent magnet 51 to 58 become the permanent magnet motor that V-shaped is placed on the permanent magnet motor rotor 60 or permanent magnet 71 to 76 are radially placed on the permanent magnet motor rotor 80 in Fig. 2 (b) For permanent magnet motors, the magnetizing equipment can only magnetize the permanent magnets outside the motor rotor, and the end of the unmagnetized permanent magnets close to the motor shaft is far away from the magnetizing equipment. This part of the permanent magnets is not easy to be saturated by magnetization. To saturate its magnetization, it is necessary to greatly increase the magnetization current, so the requirements for magnetization power supply are high, especially for large permanent magnet motors, the capacity and volume of magnetization power supply will be very large, and the price will be very high.

In addition, when magnetizing in the traditional post-magnetization method, it is necessary to align the magnetic pole axis of the magnetizer with the magnetic pole positioning of the permanent magnet motor. On the surface of the rotor 90 , the symmetry axes 121 , 122 , 123 , 124 of the magnetic field of the magnetizer 100 should be aligned with the motor permanent magnet pole axes 131 , 132 , 133 , 134 respectively. If the positioning is not accurate and the axis deviates, a large unbalanced torque will be generated and the permanent magnet can only be partially magnetized or not.

The structure, permanent magnet placement and shape of permanent magnet motors vary widely. For the traditional post-magnetization method, permanent magnet motors with different motor structures, permanent magnet placement methods and shapes require different magnetization equipment, so the traditional post-magnetization method is suitable. The performance is poor, and different magnetizing equipment cannot be used universally, causing a lot of waste. This greatly increases the assembly cost of the permanent magnet motor. For example, to magnetize the rotors of permanent magnet motors with different radii or poles, different types of magnetizing equipment must be used, and different types of magnetizing equipment cannot be used universally.

Another important problem with the permanent magnets of permanent magnet motors is that the permanent magnets may produce irreversible demagnetization or demagnetization under the action of demagnetization caused by excessive temperature or inrush current, as well as severe mechanical vibration, which makes the performance of permanent magnet motors Dropped and even unusable. Remagnetization after demagnetization is difficult to achieve for the first magnetization method. For the traditional post-magnetization method, the equipment must be shut down first, the permanent magnet motor must be disassembled again, and then the part with the permanent magnet is placed in the magnetization equipment for magnetization, and then assembled after magnetization. For example, after the permanent magnet of the permanent magnet wind turbine loses magnetism, the fan must first be shut down, then disconnected from the grid, the fan blades removed, and then the entire fan is disassembled from the fan bracket tens of meters high. Then transport it back to the factory, remove the fan rotor from the stator, and send it to the magnetizing equipment for magnetization. After the magnetization is completed, reassemble the motor, send it back to the wind farm, and install it on the fan bracket again. A very time-consuming, laborious and costly process. Therefore, it is of great practical significance to avoid the loss of magnetism of the permanent magnet and to facilitate re-magnetization after the loss of magnetism.

In some cases, permanent magnet motors need to demagnetize the permanent magnets. In the current process, small permanent magnet motors are often put directly into the heating furnace to heat the permanent magnets to demagnetize. Such demagnetization will easily damage the insulation of the equipment and easily cause the surface of the permanent magnets to oxidize. This method is also not practical for large permanent magnet motors.

Contents of the invention

The purpose of the present invention is to provide a permanent magnet motor magnetization method, which solves the problem that the permanent magnet of the permanent magnet motor is difficult to assemble, and the permanent magnet motor needs to be completely disassembled before remagnetization after the permanent magnet of the permanent magnet motor loses magnetism.

Another object of the present invention is to provide a magnetization assembly for the above magnetization method.

A method for magnetizing a permanent magnet motor, specifically: first winding a magnetizing coil on the surface of an unmagnetized permanent magnet, then installing the unmagnetized permanent magnet wound with a magnetizing coil on the motor rotor or stator, and then The stator and rotor of the permanent magnet motor are assembled. After the assembly, the magnetizing coil is charged. The direction of the magnetizing magnetic field generated by the coil is the same as that of the unmagnetized permanent magnet. The unmagnetized permanent magnet is magnetized into a permanent magnet to realize permanent magnetization. Magnetization of the motor.

Further, after the magnetization is completed, the magnetization coil remains on the permanent magnet and is short-circuited.

The magnetizing assembly realizing the magnetizing method includes an unmagnetized permanent magnet and a magnetizing coil wound on the surface of the unmagnetized permanent magnet, and the unmagnetized permanent magnet is composed of one or more unmagnetized permanent magnet blocks, The magnetized magnetic field generated by coil charging is in the same direction as that of the unmagnetized permanent magnet.

Further, the magnetized coil is directly wound on the unmagnetized permanent magnet, or the magnetized coil is prefabricated into an assembly and then fitted on the unmagnetized permanent magnet.

Technical effect of the present invention is reflected in:

1. The magnetizing method in the present invention can solve the assembly problem of the permanent magnet of the permanent magnet motor to the greatest extent. For a permanent magnet motor with permanent magnets located on the internal moving parts of the motor, it mainly refers to a motor with permanent magnets located on the inner rotor. The installation process is shown in Figure 4(a). Compared with the traditional post-magnetization method, the present invention can The stator and rotor of the magneto should be magnetized after installation, which can avoid the difficulty of assembling the stator and rotor of the permanent magnet motor; when the permanent magnet is only located on the stationary part of the motor or on the external moving part of the motor, it mainly includes the permanent magnet located on the stator or outer rotor In the above situation, the assembly of the permanent magnet motor is simpler. The installation process is shown in Figure 4(b). After the permanent magnet motor is fully assembled, the unmagnetized permanent magnet can be magnetized.

2. Compared with the traditional magnetization method, the magnetization method in the present invention requires a significantly lower magnetization power supply, and can flexibly cooperate with the power supply. This is because the magnetizing coil is wound on the surface of the unmagnetized permanent magnet, and the direction of the magnetizing magnetic field generated by the magnetizing coil is basically the same as that of the permanent magnet. The reluctance magnetic circuit greatly reduces the power supply requirement, minimizes the demand for magnetizing power supply, and makes it possible to magnetize the large permanent magnet motor as a whole. In addition, if the permanent magnet motor can adopt a segmented magnetization method, the magnetization power supply can be further miniaturized, and the required power supply capacity can be reduced to the minimum, so that the permanent magnet motor can be magnetized at the work site without having to do it in the factory building. Magnetization, which also avoids the potential safety hazards caused by permanent magnet demagnetization and strong magnetic force caused by vibration during transportation. Each magnetizing component can flexibly change the series-parallel connection mode according to the power supply situation. For example, when the power supply is in the form of low voltage and high current, the parallel form can be used, and the high voltage and small current can be used in series form.

(3) The present invention has wide applicability. In the present invention, according to the shape of the unmagnetized permanent magnet, the magnetizing coil is wound on its surface, so that the direction of the magnetic field generated by the magnetizing coil is consistent with the magnetizing direction of the permanent magnet. Variations in the size of the magneto structure, as well as the placement and shape of the permanent magnets.

(4) There is no need for positioning between the permanent magnet of the present invention and the magnetizing equipment. For the traditional post-magnetization method, precise positioning is required between the permanent magnet and the magnetization equipment. If the positioning is not accurate, it will cause insufficient permanent magnet magnetization or deviation in direction, resulting in unbalanced torque. There is no positioning problem in the present invention, as long as the installation accuracy of the magnetizing assembly can be ensured, the position accuracy of the magnetic poles can be automatically ensured.

(5) The present invention does not increase the weight and volume of the permanent magnet motor. This is because the magnetic circuit of the magnetic field generated by the magnetizing coil is consistent with the working magnetic circuit of the permanent magnet when the permanent magnet is working normally. In order to fully apply the magnetism of the permanent magnet in the design of the permanent magnet motor, the working magnetic circuit of the permanent magnet The reluctance is as small as possible, so the magnetizing coil can make full use of the minimum reluctance magnetic circuit provided by the permanent magnet motor, thereby reducing the required magnetizing power supply capacity. In addition, the coil is not located on the main working magnetic circuit of the permanent magnet motor, so it has little influence on the working magnetic circuit of the permanent magnet motor. The reduction of magnetizing energy reduces the amount of coil wire. In addition, if the space occupied by the coil is originally an electrical steel sheet, after considering the coil filling factor, the density of the coil is smaller than that of the electrical steel sheet, so the weight and volume of the equipment will not be increased.

(6) The present invention makes little changes to the existing permanent magnet motor. Existing permanent magnet motors can be adapted to the present invention with minor modifications, the main change required by the permanent magnet motor being to increase the space occupied by the coils. This only needs to process the space occupied by the coil together during processing.

(7) The present invention has lower requirements on the structural strength of the magnetizing coil and the motor. The traditional magnetizing method needs a very large magnetizing current, so it has a strong electromagnetic force, and it is easy to damage the mechanical structure of the magnetizing equipment and the permanent magnet motor, so the mechanical strength of the magnetizing equipment and the permanent magnet motor is required to be high. In the present invention, the magnetization current required for magnetization is greatly reduced, and has little influence on the mechanical structure of the permanent magnet motor itself. In addition, the magnetizing coil in the present invention is placed in the equipment, and the supporting structure of the permanent magnet motor can be used, such as using the electrical steel sheet of the motor stator or rotor as the supporting structure, which limits the stress and deformation of the coil, thereby reducing or eliminating the need for the coil. Reinforced structure.

(8) In the present invention, the demagnetization magnetic field caused by the fault current can be weakened, and the loss of magnetism of the permanent magnet can be avoided. After the magnetization of the present invention is completed, the magnetization coil is retained and short-circuited, and according to Lenz's law, the closed coil has the ability to resist changes in magnetic flux. When the permanent magnet motor fails, a large fault current will be generated, which in turn will generate a large demagnetizing magnetic field. If no measures are taken, the permanent magnet will lose its magnetism. The method of short-circuiting the coil can induce a magnetic field in the opposite direction to weaken the demagnetization effect of the external magnetic field on the permanent magnet, effectively protecting the permanent magnet from loss of magnetization. The magnetizing components can be shorted separately or connected in series and parallel.

(9) The present invention facilitates re-magnetization of the permanent magnet of the permanent magnet motor after demagnetization. It is a time-consuming, laborious and costly process to remagnetize the permanent magnet motor after demagnetization in the traditional magnetization method. In the present invention, the permanent magnet motor can use the component coil wound on the permanent magnet to remagnetize the permanent magnet. For the permanent magnet motor whose permanent magnet is located on the inner rotor, it is only necessary to remove the end cover, and connect the magnetizing power supply to the component coil to remagnetize the permanent magnet. This avoids completely dismantling the stator and rotor of the motor, thereby saving a lot of time, manpower and material resources, and effectively reducing costs. For the situation that the permanent magnet is located on the stator or the outer rotor, it is not necessary to disassemble the motor, but only need to connect the magnetizing power supply to the magnetizing coil to remagnetize the demagnetized permanent magnet.

(10) The present invention facilitates the demagnetization of permanent magnets of permanent magnet motors. When the permanent magnet of the permanent magnet motor needs to be demagnetized, the present invention only needs to feed an alternating attenuation current into the magnetizing coil to realize the demagnetization of the permanent magnet, so that the insulation of the motor winding and the anti-oxidation layer on the surface of the permanent magnet can not be damaged.

Description of drawings

Figure 1 is an explanatory diagram of the permanent magnet system of the permanent magnet motor.

Figure 2 is a schematic cross-sectional view of the permanent magnet placement method of a part of the permanent magnet motor, 2(a) is a V-shaped permanent magnet placed on the motor rotor, and 2(b) is a permanent magnet radially placed on the motor rotor

Fig. 3 is a schematic diagram showing the alignment of the magnetic pole direction of the permanent magnet motor and the magnetizing magnetic field direction of the magnetizing equipment.

Fig. 4 is the schematic diagram of the assembly process of the permanent magnet motor of the present invention, 4 (a) is the assembly flow chart of the permanent magnet motor with permanent magnets located on the internal moving parts of the motor, and 4 (b) is the permanent magnets located only on the stationary parts of the motor or outside the motor Flow chart of permanent magnet motor assembly on moving parts.

Fig. 5 is a schematic diagram of an example of a magnetizing coil assembly of the present invention, 5 (a) is a one-eighth figure of a permanent magnet motor rotor with a magnetizing assembly installed, 5 (b) is a schematic diagram of a magnetizing assembly, and 6 (c) is a magnetization Component exploded schematic.

Fig. 6 is a schematic diagram of an example of the assembly process of the permanent magnet motor in which the permanent magnet is located on the inner rotor of the motor according to the present invention.

Fig. 7 is a schematic diagram of an example of the assembly process of a permanent magnet motor in which the permanent magnet is located on the outer rotor of the motor according to the present invention.

Fig. 8 is a schematic diagram of the permanent magnet demagnetization protection method of the present invention.

Detailed ways

The following are specific embodiments of the present invention, and these examples further illustrate the technical characteristics of the present invention, but the present invention is not limited to these examples.

The first embodiment is about the manufacture and composition of the magnetizing assembly.

The magnetizing assembly mainly includes two parts: an unmagnetized permanent magnet and a coil, wherein the unmagnetized permanent magnet is processed into a desired shape by an unmagnetized permanent magnet block, and Fig. 5 (a) shows that the magnetizing assembly 141, 142 has been installed on the Situation on the permanent magnet motor rotor 170; Fig. 5 (b) has shown a kind of method that the non-magnetized permanent magnet 150 and the magnetized coil 160 are assembled into the magnetized assembly, and its method is that the coil 160 is directly set to the non-magnetized permanent magnet. on the magnet 150.

Fig. 5 (c) shows that the magnetizing assembly 142 is made of an unmagnetized permanent magnet 150 and a coil 160, wherein the cuboid unmagnetized permanent magnet 150 is bonded by 6 unmagnetized permanent magnet blocks 151 to 156, and the coil 160 is According to the geometric dimensions of the unmagnetized permanent magnet 150 , it is wound from wires.

second embodiment

Fig. 6 takes the permanent magnet motor with the permanent magnet on the inner rotor as an example, illustrating a method for installing and magnetizing the permanent magnet motor in the present invention when the permanent magnet is located on the internal moving parts of the motor, and its installation and magnetizing method It is first to install the magnetizing components 201 to 206 into the corresponding slots of the permanent magnet motor rotor 210 without components installed, and then assemble the complete rotor 220, then assemble the permanent magnet motor stator 230 and the rotor 220, and use the support 250 The rotor 220 is supported, and the magnetizing coils of the magnetizing components 201 to 206 are connected in series to the magnetizing power supply 240 , the power is discharged, and the magnetizing coils generate a magnetizing magnetic field to magnetize unmagnetized permanent magnets into permanent magnets. Finally, the magnetization coils of the magnetization components 201 to 206 are short-circuited and the end cover 260 is assembled to complete the magnetization and assembly of the entire motor 270 .

third embodiment

Fig. 7 takes the permanent magnet motor with the permanent magnet on the outer rotor as an example, illustrating a method for installing and magnetizing the permanent magnet motor in the present invention when the permanent magnet is located on the external moving parts of the motor, and its installation and magnetizing method It is first to install each magnetizing assembly 300 to 309 into the corresponding groove of the permanent magnet motor outer rotor 310 without assembly, and then assemble the complete outer rotor 320, and then assemble the end cover 340, the permanent magnet motor stator 330 and the outer rotor 320 together to complete the assembly of the entire motor 350, and then connect the magnetizing coils of the magnetizing components 300 to 309 to the magnetizing power supply 360 after being connected in series, the power supply is discharged, and the magnetizing coils generate a magnetizing magnetic field to realize permanent magnetization without magnetization. The magnets are magnetized as permanent magnets. Finally, the magnetizing coils of the magnetizing components 300 to 309 are short-circuited.

Fourth embodiment

Fig. 8 takes the inner rotor permanent magnet motor as an example to illustrate the method for preventing loss of magnetization of the magnetization assembly. , 412, 413, 414, 415 and 416 are respectively short-circuited, and the short-circuited coils can prevent the demagnetization of the permanent magnet due to the demagnetization magnetic field.

Claims (4)

1. magneto magnetization method; Be specially: at first on magnetizing permanent magnetism surface, twine the coil that magnetizes, and then the not charging permanent magnet that will be wound with the coil that magnetizes is installed on rotor or the stator, then the permanent magnet motor stator rotor assembled; Assembled the back to the coil charges that magnetizes; Coil produces, and the magnetic direction that magnetizes is identical with the magnetizing direction of charging permanent magnet not, and charging permanent magnet is not geomagnetic into permanent magnet, the magnetizing of realization magneto; Magnetize after the completion, the coil that magnetizes is retained on the permanent magnet.

2. magnetization method according to claim 1 is characterized in that, after the completion of magnetizing, with the coil short circuit that magnetizes that is retained on the permanent magnet.

3. realize the assembly that magnetizes of claim 1 or 2 said magnetization methods; Comprise not charging permanent magnet and be wrapped in the not lip-deep coil that magnetizes of charging permanent magnet; Not charging permanent magnet by one or more not the magnetizing permanent magnetism piece form, coil charges produces, and the magnetic field of magnetizing is identical with the magnetizing direction of charging permanent magnet not.

4. the assembly that magnetizes according to claim 3 is characterized in that, the said coil that magnetizes directly is wrapped in not on the charging permanent magnet or the coil that magnetizes is prefabricated into earlier to refill behind the assembly and is set to not on the charging permanent magnet.

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