Starting method for assisting single-phase brushless direct current motor and cooling fan

Abstract

The invention relates to the technical field of motors, and particularly discloses a starting method for assisting a single-phase brushless direct current motor and a cooling fan. The product of magnetic energy charged into a permanent magnet by a customized waveform is larger than the product of magnetic energy charged into the permanent magnet by a sinusoidal waveform; therefore, attraction forces applied to the rotor and the stator silicon steel sheet of the single-phase brushless direct current motor are different, so that the rotor deflects to avoid a starting dead point position, and the starting of the single-phase brushless direct current motor can be assisted. According to the invention, the stator silicon steel sheet does not need to be designed with large and small edges, the beneficial effect of assisting the starting of the single-phase brushless direct current motor can be achieved only by changing the magnetizing waveform of the permanent magnet, and meanwhile, a large number of different models of stator silicon steel sheets without large and small edge design can also be shared by the single-phase brushless direct current motor; the material cost and the development time are saved, and the problems of long development time and high material cost caused by different side sizes of silicon steel sheets of motors of different models in the prior art are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of motors, and in particular to a starting method for assisting a single-phase brushless DC motor and a heat dissipation fan. Background Art

[0002] In order to ensure the smooth start of the motor, the current single-phase brushless DC motor generally adopts the design of large and small sides of silicon steel sheets (that is, the boot of the silicon steel sheet is symmetrically designed). If the large and small sides of the silicon steel sheet are not designed, the motor rotor will stay in a certain position due to mutual attraction when no external force is applied to the motor rotor. At this time, when the motor is powered on, the magnetic potential generated by the stator coil is on the same line as the magnetic potential of the permanent magnet, but in opposite directions. The component of the synthetic magnetic potential along the tangent direction of the circle is 0, and the starting torque cannot be generated. At this time, the motor rotor cannot start running. This position is called the starting dead point of the single-phase brushless DC motor. However, due to the emergence of a large number of different types of motors, it is required to manufacture large and small sides of silicon steel sheets of different sizes, which leads to the problems of long development time and high material costs. Summary of the invention

[0003] The purpose of the present invention is to provide a starting method and a cooling fan for assisting a single-phase brushless DC motor, so as to solve the problem in the prior art that the large and small sides of silicon steel sheets of motors of different models are different, resulting in long development time and high material cost.

[0004] On the one hand, the present invention provides a method for assisting the starting of a single-phase brushless DC motor, wherein the single-phase brushless DC motor comprises a motor housing, a stator silicon steel sheet and a permanent magnet, wherein the permanent magnet surrounds the inner wall of the motor housing, and the magnetism of adjacent magnetic poles of the permanent magnet is opposite, and the stator silicon steel sheet is arranged in the motor housing. The method for assisting the starting of the single-phase brushless DC motor comprises:

[0005] When the boot portion of the stator silicon steel sheet is symmetrically designed, a customized waveform is used to magnetize the permanent magnet;

[0006] The magnetic energy product charged into the permanent magnet using the customized waveform is greater than the magnetic energy product charged into the permanent magnet using the sinusoidal waveform.

[0007] As an optional technical solution for assisting the starting method of a single-phase brushless DC motor, the magnetic energy product charged into the permanent magnet by the customized waveform is greater than the magnetic energy product charged into the permanent magnet by the sine waveform, including:

[0008] The magnetic energy product charged by the customized waveform to the S pole of the permanent magnet is greater than the magnetic energy product charged by the sinusoidal waveform to the S pole of the permanent magnet, and the magnetic energy product charged by the customized waveform to the N pole of the permanent magnet is greater than the magnetic energy product charged by the sinusoidal waveform to the N pole of the permanent magnet.

[0009] As an optional technical solution for assisting the starting method of a single-phase brushless DC motor, the customized waveform is a quasi-sine wave.

[0010] As an optional technical solution for assisting the starting method of the single-phase brushless DC motor, magnetizing the permanent magnet using the customized waveform includes:

[0011] The customized waveform charges the S pole and the N pole of the permanent magnet with equal magnetization intensities and in opposite directions.

[0012] As an optional technical solution of the method for assisting the starting of a single-phase brushless DC motor, the method for assisting the starting of a single-phase brushless DC motor further includes:

[0013] The single-phase brushless DC motor also includes a stator coil arranged on the stator silicon steel sheet;

[0014] When the single-phase brushless DC motor is powered on, a synthetic magnetic potential is formed between the magnetic potential generated by the stator coil and the magnetic potential generated by the permanent magnet, and the torque generated by the component of the synthetic magnetic potential along the tangential direction of the stator silicon steel sheet is greater than the starting resistance of the single-phase brushless DC motor.

[0015] On the other hand, the present invention provides a cooling fan, which uses the starting method of the auxiliary single-phase brushless DC motor in any of the above-mentioned schemes, and the cooling fan includes a fan frame, fan blades and a single-phase brushless DC motor, the fan blades and the single-phase brushless DC motor are both arranged in the cavity of the fan frame, and the single-phase brushless DC motor and the fan blades are driven and connected to drive the fan blades to rotate.

[0016] As an optional technical solution for the cooling fan, the single-phase brushless DC motor includes a motor housing, a stator silicon steel sheet and a plurality of permanent magnets. The motor housing is arranged in the cavity of the fan frame. The plurality of permanent magnets are alternately surrounded by the inner wall of the motor housing, and the magnetic properties of adjacent permanent magnets are opposite. The stator silicon steel sheet is arranged in the motor housing and coaxially with the motor housing.

[0017] As an optional technical solution for the heat dissipation fan, the stator silicon steel sheet includes an annular body and a plurality of boots, the plurality of boots are arranged at intervals along the circumference of the annular body, and the plurality of boots and the plurality of permanent magnets are arranged in one-to-one correspondence.

[0018] As an optional technical solution for the cooling fan, the cooling fan also includes a motor control board and a controller, the motor control board is arranged in the cavity of the fan frame, the controller is electrically connected to the single-phase brushless DC motor through the motor control board, and the controller controls the operation of the single-phase brushless DC motor.

[0019] As an optional technical solution of the heat dissipation fan, the heat dissipation fan further includes a power line, and the single-phase brushless DC motor can be connected to a power supply device through the power line.

[0020] The beneficial effects of the present invention are:

[0021] The present invention provides a method for assisting the starting of a single-phase brushless DC motor, and the method comprises: when the boot portion of the stator silicon steel sheet is symmetrically designed, a customized waveform is used to magnetize the permanent magnet; wherein the magnetic energy product charged into the permanent magnet by the customized waveform is greater than the magnetic energy product charged into the permanent magnet by the sine waveform. The method for assisting the starting of a single-phase brushless DC motor provided by the present invention, because the magnetic energy product charged into the permanent magnet by the customized waveform is greater than the magnetic energy product charged into the permanent magnet by the sine waveform, is configured in this way, so that the rotor and the stator silicon steel sheet of the single-phase brushless DC motor are subjected to different attractive forces, causing the rotor to deflect and avoid the starting dead point position, thereby being able to assist the starting of the single-phase brushless DC motor. By utilizing the method for assisting the starting of a single-phase brushless DC motor of the present invention, it is not necessary to require the stator silicon steel sheet to have a large and small side design. It is only necessary to change the magnetizing waveform of the permanent magnet to achieve the beneficial effect of assisting the starting of the single-phase brushless DC motor. At the same time, a large number of different types of stator silicon steel sheets with no large and small side designs can also be shared by the single-phase brushless DC motor, saving material costs and development time, thereby effectively solving the problem in the prior art that the large and small side sizes of silicon steel sheets of motors of different types are different, resulting in long development time and high material costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a flow chart of a method for assisting a single-phase brushless DC motor in starting according to an embodiment of the present invention;

[0023] Figure 2 A schematic diagram of the structure of a heat dissipation fan in an embodiment of the present invention;

[0024] Figure 3 An exploded view of a heat dissipation fan in an embodiment of the present invention;

[0025] Figure 4 A schematic diagram of a heat dissipation fan structure in an embodiment of the present invention;

[0026] Figure 5 A comparison waveform diagram of a customized waveform and a sine waveform in an embodiment of the present invention;

[0027] Figure 6 A schematic diagram of the structure of a motor part in an embodiment of the present invention;

[0028] Figure 7 Schematic diagram of the structure of a customized magnetizing fixture for permanent magnets in an embodiment of the present invention.

[0029] In the figure:

[0030] 1. Single-phase brushless DC motor; 11. Motor housing; 12. Stator silicon steel sheet; 121. Ring body; 122. Boot; 13. Permanent magnet;

[0031] 2. Fan frame;

[0032] 3. Fan blades;

[0033] 4. Motor control board;

[0034] 5. Power cord;

[0035] 6. Magnetizing coil;

[0036] 7. Metal middle tube. DETAILED DESCRIPTION

[0037] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. 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.

[0038] In the description of the present invention, it should be noted that the orientations or positional relationships indicated by the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. Among them, the terms "first position" and "second position" are two different positions, and the first feature "above", "above" and "above" the second feature include the first feature being directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. The first feature "below", "below" and "below" the second feature include the first feature being directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0039] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it 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 it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0040] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0041] like Figures 1 to 6 As shown, this embodiment provides a method for assisting the starting of a single-phase brushless DC motor. The single-phase brushless DC motor 1 includes a motor housing 11, a stator silicon steel sheet 12 and a permanent magnet 13. The permanent magnet 13 surrounds the inner wall of the motor housing 11. The magnetism of adjacent poles of the permanent magnet 13 is opposite. The stator silicon steel sheet 12 is arranged in the motor housing 11. The method for assisting the starting of the single-phase brushless DC motor includes magnetizing the permanent magnet 13 with a customized waveform when the boot portion 122 of the stator silicon steel sheet 12 is symmetrically designed; wherein the magnetic energy product charged into the permanent magnet 13 with the customized waveform is greater than the magnetic energy product charged into the permanent magnet 13 with a sinusoidal waveform.

[0042] By using the auxiliary single-phase brushless DC motor starting method provided by the present invention, since the magnetic energy product charged into the permanent magnet 13 by the customized waveform is greater than the magnetic energy product charged into the permanent magnet 13 by the sine waveform, the rotor and the stator silicon steel sheet 12 of the single-phase brushless DC motor 1 are subjected to different attractive forces, causing the rotor to deflect and avoid the starting dead point position, thereby being able to assist the starting of the single-phase brushless DC motor 1. By using the auxiliary single-phase brushless DC motor starting method of the present invention, it is not necessary to require the stator silicon steel sheet 12 to have a large and small side design. It is only necessary to change the magnetizing waveform of the permanent magnet 13 to achieve the beneficial effect of assisting the starting of the single-phase brushless DC motor. At the same time, a large number of different models of stator silicon steel sheets 12 without large and small side designs can also be shared by the single-phase brushless DC motor 1, saving material costs and development time, thereby effectively solving the problem of different large and small side sizes of silicon steel sheets of motors of different models in the prior art, resulting in long development time and high material costs.

[0043] It should be noted that if Figure 5 The following is a comparison of the customized waveform and the sine waveform. The horizontal axis is the magnetization angle, the unit is Deg; the vertical axis represents the magnetization intensity, the unit is mT, and the directions of the N pole and the S pole are also shown. The magnetic energy product can be expressed as the area formed between the horizontal axis and the customized waveform. Figure 5It can be seen that, regardless of the N pole or the S pole, the area formed by the customized waveform and the horizontal coordinate is larger than the area formed by the sinusoidal waveform and the horizontal coordinate, that is, the magnetic energy product of the customized waveform is larger than the magnetic energy product of the sinusoidal waveform. With this arrangement, the rotor and the stator silicon steel sheet 12 of the single-phase brushless DC motor 1 are subjected to different attractive forces, so that the rotor is deflected and avoids the starting dead point position, thereby assisting the starting of the single-phase brushless DC motor 1.

[0044] In some embodiments, the magnetic energy product charged into the permanent magnet 13 by the customized waveform is greater than the magnetic energy product charged into the permanent magnet 13 by the sine waveform, including: the magnetic energy product charged into the S pole of the permanent magnet 13 by the customized waveform is greater than the magnetic energy product charged into the S pole of the permanent magnet 13 by the sine waveform, and the magnetic energy product charged into the N pole of the permanent magnet 13 by the customized waveform is greater than the magnetic energy product charged into the N pole of the permanent magnet 13 by the sine waveform. This arrangement can effectively ensure that the rotor and the stator silicon steel sheet 12 of the single-phase brushless DC motor 1 are subjected to different attractive forces, causing the rotor to deflect and avoid the starting dead point position.

[0045] In this embodiment, the customized waveform is a quasi-sine wave, which is helpful to reduce the vibration of the motor and improve the sound quality of the motor.

[0046] Specifically, magnetizing the permanent magnet 13 using a customized waveform includes: the magnetizing intensities charged into the S pole and the N pole of the permanent magnet 13 by the customized waveform are equal, and the magnetizing directions are opposite, so that the normal operation of the motor can be ensured after magnetization.

[0047] Furthermore, the starting method of the auxiliary single-phase brushless DC motor also includes: the single-phase brushless DC motor 1 also includes a stator coil arranged on the stator silicon steel sheet 12; when the single-phase brushless DC motor 1 is energized, a synthetic magnetic potential is formed between the magnetic potential generated by the stator coil and the magnetic potential generated by the permanent magnet 13. At this time, the torque generated by the component of the synthetic magnetic potential along the tangential direction of the stator silicon steel sheet 12 is greater than the starting resistance of the single-phase brushless DC motor 1, so that the starting dead point position can be avoided.

[0048] This embodiment also provides a cooling fan, which uses the auxiliary starting method of the single-phase brushless DC motor in the above scheme. The cooling fan includes a fan frame 2, fan blades 3 and a single-phase brushless DC motor 1. The fan blades 3 and the single-phase brushless DC motor 1 are both arranged in the cavity of the fan frame 2, and the single-phase brushless DC motor 1 is driven and connected to the fan blades 3, so as to achieve the purpose of driving the fan blades 3 to rotate.

[0049] In some embodiments, the single-phase brushless DC motor 1 includes a motor housing 11, a stator silicon steel sheet 12, and a permanent magnet 13. The motor housing 11 is disposed in the cavity of the fan frame 2, the permanent magnet 13 surrounds the inner wall of the motor housing 11, the adjacent magnetic poles of the permanent magnet 13 have opposite magnetic properties, and the stator silicon steel sheet 12 is disposed in the motor housing 11 and is coaxially disposed with the motor housing 11.

[0050] Furthermore, if Figure 6 As shown, in this embodiment, it is a single-phase 4-slot 4-pole motor. The stator silicon steel sheet 12 includes an annular body 121 and a plurality of boots 122, the plurality of boots 122 are arranged at intervals along the circumference of the annular body 121, and the plurality of boots 122 and the plurality of permanent magnets 13 are arranged one by one.

[0051] Specifically, the cooling fan further comprises a motor control board 4 and a controller. The motor control board 4 is arranged in the cavity of the fan frame 2, and the controller is electrically connected to the single-phase brushless DC motor 1 through the motor control board 4, so that the single-phase brushless DC motor 1 can be controlled by the controller to work.

[0052] In this embodiment, if Figure 3 and Figure 4 As shown, the cooling fan further includes a power line 5 , and the single-phase brushless DC motor 1 can be connected to a power supply device via the power line 5 .

[0053] like Figure 7 As shown, the present invention also provides a magnetizing head jig, wherein the magnetizing head jig includes a silicon steel sheet body, a magnetizing coil 6 and a metal middle tube 7, wherein the metal middle tube 7 is located at the center of the silicon steel sheet body, and the magnetizing coil 6 is wound around the silicon steel sheet body. In order to customize the required magnetizing waveform, the magnetizing head jig needs to be redesigned, so that the silicon steel sheet body boot inside the magnetizing head is changed from the original symmetrical design to an asymmetrical design, that is, the A side is slightly larger than the B side. This asymmetrical design of the silicon steel sheet boot of the magnetizing head can charge the required magnetic field waveform of the permanent magnet 13, so as to assist the starting of the single-phase DC brushless motor.

[0054] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A method for assisting the starting of a single-phase brushless DC motor, the single-phase brushless DC motor (1) comprising a motor housing (11), a stator silicon steel sheet (12) and a permanent magnet (13), the permanent magnet (13) surrounding the inner wall of the motor housing (11), the adjacent magnetic poles of the permanent magnet (13) having opposite magnetic properties, the stator silicon steel sheet (12) being arranged in the motor housing (11), characterized in that: The auxiliary single-phase brushless DC motor starting method comprises: When the boot portion (122) of the stator silicon steel sheet (12) is symmetrically designed, a customized waveform is used to magnetize the permanent magnet (13); The magnetic energy product charged into the permanent magnet (13) using the customized waveform is greater than the magnetic energy product charged into the permanent magnet (13) using a sinusoidal waveform.

2. The starting method of the auxiliary single-phase brushless DC motor according to claim 1, characterized in that: The magnetic energy product charged into the permanent magnet (13) by the customized waveform is greater than the magnetic energy product charged into the permanent magnet (13) by the sine waveform, comprising: The magnetic energy product of the customized waveform charged into the S pole of the permanent magnet (13) is greater than the magnetic energy product of the sinusoidal waveform charged into the S pole of the permanent magnet (13), and the magnetic energy product of the customized waveform charged into the N pole of the permanent magnet (13) is greater than the magnetic energy product of the sinusoidal waveform charged into the N pole of the permanent magnet (13).

3. The starting method of the auxiliary single-phase brushless DC motor according to claim 1, characterized in that: The customized waveform is a sine-like wave.

4. The starting method of the auxiliary single-phase brushless DC motor according to claim 1, characterized in that: Using the customized waveform to magnetize the permanent magnet (13) includes: The customized waveform charges the S pole and the N pole of the permanent magnet (13) with equal magnetization intensities and in opposite directions.

5. The starting method of the auxiliary single-phase brushless DC motor according to claim 1, characterized in that: The auxiliary single-phase brushless DC motor starting method also includes: The single-phase brushless DC motor (1) further comprises a stator coil arranged on the stator silicon steel sheet (12); When the single-phase brushless DC motor (1) is powered on, a composite magnetic potential is formed between the magnetic potential generated by the stator coil and the magnetic potential generated by the permanent magnet (13), and the torque generated by the component of the composite magnetic potential along the tangential direction of the stator silicon steel sheet (12) is greater than the starting resistance of the single-phase brushless DC motor (1).

6. A cooling fan, characterized in that: The method for starting an auxiliary single-phase brushless DC motor according to any one of claims 1 to 5 is applied, wherein the cooling fan comprises a fan frame (2), fan blades (3) and a single-phase brushless DC motor (1), wherein the fan blades (3) and the single-phase brushless DC motor (1) are both arranged in a cavity of the fan frame (2), and the single-phase brushless DC motor (1) and the fan blades (3) are driven and connected to drive the fan blades (3) to rotate.

7. The heat dissipation fan according to claim 6, characterized in that: The single-phase brushless DC motor (1) comprises a motor housing (11), a stator silicon steel sheet (12) and a plurality of permanent magnets (13); the motor housing (11) is arranged in a cavity of the fan frame (2); the plurality of permanent magnets (13) alternately surround the inner wall of the motor housing (11), and the magnetic properties of adjacent permanent magnets (13) are opposite; the stator silicon steel sheet (12) is arranged in the motor housing (11) and is coaxially arranged with the motor housing (11).

8. The heat dissipation fan according to claim 7, characterized in that: The stator silicon steel sheet (12) comprises an annular body (121) and a plurality of boots (122), wherein the plurality of boots (122) are arranged at intervals along the circumference of the annular body (121), and the plurality of boots (122) and the plurality of permanent magnets (13) are arranged in a one-to-one correspondence.

9. The heat dissipation fan according to claim 6, characterized in that: The cooling fan further comprises a motor control board (4) and a controller, wherein the motor control board (4) is arranged in the cavity of the fan frame (2), and the controller is electrically connected to the single-phase brushless DC motor (1) via the motor control board (4), and the controller controls the operation of the single-phase brushless DC motor (1).

10. The heat dissipation fan according to claim 6, characterized in that: The cooling fan also includes a power line (5), and the single-phase brushless DC motor (1) can be connected to a power supply device via the power line (5).

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