Magnetization method of brushless DC motor

Abstract

The present application discloses a method for magnetizing a brushless DC motor. The stator of the brushless DC motor has three groups of armature coils, and the permanent magnet rotor arranged opposite to the stator is built-in and matched. With any slot of the stator slot as the starting point, the armature coils on the stator are defined as the first phase coil, the second phase coil and the third phase coil in sequence; the negative pole of the magnetic power supply is connected to the first phase coil, the positive pole of the magnetic power supply is connected to at least one of the second phase coil and the third phase coil, and after the relative position of the armature coil and the permanent magnet is fixed, a pulse current is introduced into the armature coil based on the magnetic power supply; the connection direction of the positive and negative poles of the magnetic power supply is exchanged to reorganize the connection between the magnetic power supply and the armature coil, and the relative position of the armature coil and the permanent magnet is adjusted by a preset angle of relative rotation of the mechanical angle; a pulse current is introduced into the armature coil based on the magnetic power supply. The problem of poor magnetization of the triangular-type brushless DC motor can be solved, so that the motor of the high-voltage platform can continue to use the built-in combined magnetization method.

Description

Technical Field

[0001] The present application relates to the technical field of manufacturing brushless DC motors, and in particular to a magnetization method for brushless DC motors. Background Art

[0002] In a general brushless DC motor, the armature coil is set on the stator core to form the stator, and the permanent magnet is installed inside the rotor core to form the rotor. The rotor is correctly built into the stator center hole to ensure that the air gap between the stator inner diameter and the rotor outer diameter is uniform. The magnetizing power supply is connected to the armature coil, and the stator and rotor are guaranteed to have a correct relative position, that is, the position of the permanent magnet relative to the armature coil, and are fixed. Adjust the voltage of the magnetizing power supply, pass a pulse voltage into the armature coil, and the armature coil flows through the pulse current to generate a magnetic field, so that the hard magnetic material is permanently magnetized. During the magnetization process, the armature coil generates a magnetizing magnetic field, and the stator and rotor cores serve as paths for the flow of magnetic lines of force.

[0003] There are generally two methods for magnetizing brushless DC motors with concentrated windings: one is to make different magnetizing tools (similar to stators) separately according to the size and structure of different rotors. The tooling is generally a two-phase stator or an armature coil with only positive and negative power lines. The advantage is that one magnet faces one coil magnetic field, and the magnetization is uniform. The disadvantage is that different tools need to be made, which is expensive and time-consuming. In addition, in offline magnetization, the rotor is prone to adsorb impurities, resulting in poor cleanliness or product damage, and the magnetized rotor is not easy to assemble; the second is to use a matching stator and rotor combination. The stator is generally a three-phase stator with UVW, and because the ratio of the number of slots to the number of poles is 3:2, that is, one magnet corresponds to 1.5 coil magnetic fields, the connection of the magnetizing power supply and the stator coil winding should be adjusted according to the different wiring forms of the stator (Y-type or triangle type) and the position of the rotor relative to the armature winding. The advantage is that this method has low production cost and is suitable for rapid correspondence in the research and development stage. The disadvantage is that it requires two magnetizations to reach saturation.

[0004] The ratio of the number of slots in the motor stator to the number of poles in the rotor of a traditional brushless DC motor is 3:2, and concentrated windings are implemented on the teeth of the stator. Due to the limitation of the motor DC voltage of 12V~500V at that time, the motor phase current was large, and the wire diameter of the copper wire of most products was thick, and the manufacturability was high, the concentrated winding Y-type connection method was used; in recent years, due to the rise of the 800V~1200V voltage platform of new energy vehicles, the DC voltage is high, the motor phase current is small, and the wire diameter of the copper wire is thinner. Considering the problems of manufacturing winding process, the concentrated winding triangle connection method has gradually begun to be used. However, at present, most of them simply use the Y-type connection stator magnetization method directly for the triangle connection stator magnetization operation, and lack of magnetization method for the built-in combination of concentrated winding triangle connection motor in three-phase brushless DC motor, resulting in poor magnetization of the three-phase brushless DC motor triangle connection. Summary of the invention

[0005] The present application aims to solve at least one of the technical problems existing in the prior art. To this end, the present application proposes a brushless DC motor magnetization method to solve the problem of poor magnetization of a three-phase brushless DC motor with a delta connection due to the simple use of a traditional magnetization method.

[0006] Specifically, the present application provides a method for magnetizing a brushless DC motor, wherein the stator of the brushless DC motor has three groups of armature coils, and a permanent magnet rotor arranged opposite to the stator is internally matched, and the method comprises:

[0007] Taking any one of the stator slots as a starting point, defining the armature coil on the stator as a first phase coil, a second phase coil and a third phase coil in sequence;

[0008] Implementing the first magnetization of the permanent magnet includes: connecting the negative pole of the magnetizing power supply with the first phase coil, the positive pole of the magnetizing power supply with at least one of the second phase coil and the third phase coil, fixing the relative position of the armature coil and the permanent magnet, and then passing a pulse current into the armature coil based on the magnetizing power supply;

[0009] Reversing the connection direction of the positive and negative poles of the magnetizing power supply to reorganize the connection between the magnetizing power supply and the armature coil, and adjusting the relative position of the armature coil and the permanent magnet by relatively rotating the armature coil by a preset angle at a mechanical angle;

[0010] Implementing the second magnetization of the permanent magnet includes: the magnetization power supply supplies a pulse current to the armature coil.

[0011] In one embodiment of the above-mentioned method for magnetizing a brushless DC motor, the three groups of armature coils form a three-phase delta connection, 3n armature coils are evenly spaced on the stator of the brushless DC motor, and the permanent magnet rotor has 2n magnetic poles, where n is a natural number.

[0012] In one embodiment of the above-mentioned magnetization method of the brushless DC motor, the first magnetization of the permanent magnet includes: connecting the negative pole of the magnetization power supply with the first phase coil, the positive pole of the magnetization power supply with the second phase coil, fixing the relative position of the armature coil and the permanent magnet, and then passing a pulse current into the armature coil based on the magnetization power supply.

[0013] In one embodiment of the above-mentioned method for magnetizing a brushless DC motor, the step of changing the connection direction of the positive and negative poles of the magnetizing power supply to reorganize the connection between the magnetizing power supply and the armature coil comprises:

[0014] Separate the negative pole of the magnetizing power supply and the first phase coil, and separate the positive pole of the magnetizing power supply and the second phase coil;

[0015] The negative pole of the magnetizing power supply is connected to the second phase coil, and the positive pole of the magnetizing power supply is connected to the first phase coil.

[0016] In one embodiment of the above-mentioned method for magnetizing a brushless DC motor, the three groups of armature coils form a three-phase Y-type connection, 3n armature coils are evenly spaced on the stator of the brushless DC motor, and the permanent magnet rotor has 2n magnetic poles, where n is a natural number.

[0017] In one embodiment of the above-mentioned method for magnetizing a brushless DC motor, the first magnetization of the permanent magnet comprises:

[0018] The negative pole of the magnetic power supply is connected to the first phase coil, the positive pole of the magnetic power supply is connected to the second phase coil and the third phase coil, and after the relative position of the armature coil and the permanent magnet is fixed, a pulse current is passed into the armature coil based on the magnetic power supply.

[0019] In one embodiment of the above-mentioned method for magnetizing a brushless DC motor, the step of changing the connection direction of the positive and negative poles of the magnetizing power supply to reorganize the connection between the magnetizing power supply and the armature coil comprises:

[0020] Separate the negative pole of the magnetizing power supply and the first phase coil, the positive pole of the magnetizing power supply and the second phase coil and the third phase coil;

[0021] The positive pole of the magnetizing power supply is connected to the first phase coil, and the negative pole of the magnetizing power supply is connected to the second phase coil and the third phase coil.

[0022] In one embodiment of the above-mentioned method for magnetizing a brushless DC motor, the adjusting the relative positions of the countless armature coils and the permanent magnet by relatively rotating the predetermined mechanical angle by a predetermined mechanical angle comprises:

[0023] The relative positions of the armature coil and the permanent magnet are adjusted by relative rotation of the mechanical angle of 180° / n.

[0024] In one embodiment of the above-mentioned magnetizing method for a brushless DC motor, the magnetizing power supply is connected to the armature coil via a wiring harness, and the wiring harness is connected to an ammeter for monitoring and displaying the pulse current output by the magnetizing power supply;

[0025] The rotor of the brushless DC motor is connected to a locking structure for locking the rotor through a reducer.

[0026] In one embodiment of the above-mentioned method for magnetizing a brushless DC motor, after performing the second magnetization of the permanent magnet, the method further comprises:

[0027] Determining whether the magnetization of the permanent magnet is saturated includes:

[0028] The output voltage of the magnetizing power supply is increased at equal intervals to repeatedly magnetize the permanent magnet, wherein the magnetization of the permanent magnet includes a first magnetization of the permanent magnet and a second magnetization of the permanent magnet;

[0029] Recording the magnetic flux value and the current value during the first magnetization and the second magnetization of the permanent magnet in each magnetization;

[0030] If the magnetic flux value remains unchanged when the output voltage of the magnetizing power supply increases, it is determined that the magnetization saturation of the permanent magnet is reached.

[0031] One or more of the above-mentioned embodiments of the present application have at least one or more of the following beneficial effects: it can be applicable to the stator magnetization of brushless DC motors with delta connection and Y connection, avoids the mistaken application of the stator magnetization method of Y connection to the magnetization operation of the stator with delta connection, can solve the current problem of poor magnetization of brushless DC motors with delta connection, and allows the motors of high-voltage platforms to continue to use the built-in combined magnetization method.

[0032] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The disclosure of the present application will become more easily understood with reference to the accompanying drawings. It is easy for those skilled in the art to understand that these drawings are only for illustrative purposes and are not intended to limit the scope of protection of the present application. In addition, similar numbers in the drawings are used to represent similar components, among which:

[0034] Figure 1 is a flow chart of a magnetization method for a brushless DC motor provided in the present application;

[0035] Figure 2 It is a schematic diagram of the positions of the armature coil and the permanent magnet in the brushless DC motor when the permanent magnet is first magnetized;

[0036] Figure 3 This is the wiring diagram of the triangle-connected armature coil and the magnetizing power supply of a brushless DC motor with a triangle connection when the permanent magnet is magnetized for the first time.

[0037] Figure 4 This is the wiring diagram of the Y-type wired brushless DC motor, the triangle-type wired armature coil and the magnetizing power supply when the permanent magnet is first magnetized;

[0038] Figure 5 It is a schematic diagram of the position of the armature coil and the magnetizing power supply in the brushless DC motor when the permanent magnet is magnetized for the second time;

[0039] Figure 6 This is the wiring diagram of the triangle-connected armature coil and the magnetizing power supply of the brushless DC motor using the triangle connection when the permanent magnet is magnetized for the second time;

[0040] Figure 7 This is the wiring diagram of the Y-type wired brushless DC motor, the triangle-type wired armature coil and the magnetizing power supply when the permanent magnet is magnetized for the second time;

[0041] Figure 8 It is a schematic diagram of the change of the magnetic flux of the permanent magnet as the output voltage of the magnetizing power supply increases with equal spacing during the repeated magnetization of the permanent magnet until the magnetization saturation;

[0042] Fig. 9 It is a schematic diagram of the system framework of the magnetic device;

[0043] Fig.10 This is a schematic diagram of the power-on and magnetization of a brushless DC motor with a triangle connection;

[0044] Fig.11 This is a schematic diagram of the Y-type brushless DC motor being energized and magnetized. DETAILED DESCRIPTION

[0045] Some embodiments of the present application are described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the present application and are not intended to limit the protection scope of the present application.

[0046] As described in the background technology, in recent years, due to production automation factors, motor efficiency, cost and other considerations, most manufacturers have gradually used magnet embedded brushless DC motors with easy speed control and high efficiency, and concentrated winding motors with concentrated windings on the stator teeth. However, due to the limitation of the motor DC voltage of 12V to 500V at that time, the motor phase current was large, and the wire diameter of most products' copper wires was thick, and the manufacturability was high, the concentrated winding Y-type wiring method was used; in recent years, due to the rise of the 800V to 1200V voltage platform of new energy vehicles, the DC voltage is high, the motor phase current is small, and the wire diameter of the copper wire is thinner. Considering the problem of manufacturing winding process, the concentrated winding triangle wiring method has gradually begun to be used. However, there has been no improvement in the magnetization method of brushless DC motors. It is simply that the built-in combined magnetization method of the Y-type wiring motor is used in the magnetization of the triangle wiring motor, resulting in the problem of poor magnetization of brushless DC motors using triangle wiring.

[0047] In order to solve the above problems, the present application creatively proposes a magnetization method for a brushless DC motor, which magnetizes the permanent magnet of the brushless DC motor twice in steps. By exchanging the positive and negative poles of the magnetization power supply in the two magnetizations, and adjusting the relative positions of the armature coil on the stator and the permanent magnet of the rotor, the problem of poor magnetization of the current triangular-connected brushless DC motor can be solved, so that the motor of the high-voltage platform can continue to use the built-in combined magnetization method.

[0048] The present application will be described in detail below through specific embodiments.

[0049] The embodiment of the present application provides a method for magnetizing a brushless DC motor, wherein the stator in the brushless DC motor has three groups of armature coils, and a permanent magnet rotor arranged opposite to the stator is internally matched. Specifically, the armature coil is arranged on the stator core and combined with the stator core to form a stator, and the permanent magnet is installed inside the rotor core to form a rotor. The rotor is correctly internally placed in the hollow of the stator to ensure that the air gap between the inner diameter of the stator and the outer diameter of the rotor is uniform.

[0050] Reference Figure 1 As shown, the magnetization methods of brushless DC motors include:

[0051] S110, starting from any one of the stator slots, sequentially defining the armature coil on the stator as a first phase coil, a second phase coil and a third phase coil.

[0052] Specifically, in the present application, the stator in the brushless DC motor has three groups of armature coils, each group of armature coils has n armature coils (n is a natural number), and taking any one of the stator slots as the starting point, the three groups of armature coils on the stator are sequentially defined as the first phase coil, the second phase coil and the third phase coil.

[0053] S120, implement the first magnetization of the permanent magnet, including: connecting the negative pole of the magnetic power supply with the first phase coil, the positive pole of the magnetic power supply with at least one of the second phase coil and the third phase coil, fixing the relative position of the armature coil and the permanent magnet, and then passing a pulse current into the armature coil based on the magnetic power supply.

[0054] Specifically, the three groups of armature coils on the stator core can be connected in a triangle connection, that is, the tail of the first phase coil of the three groups of armature coils is connected to the head of the second phase coil, so that the head and tail are connected to form a triangle shape. The three groups of armature coils on the stator core can also be connected in a Y-type connection, that is, the tails of the three groups of armature coils are connected together to form a neutral point.

[0055] The three groups of armature coils in the brushless DC motor are connected in a triangle shape, 3n armature coils are evenly spaced on the stator of the brushless DC motor, the permanent magnet rotor has 2n magnetic poles, n is a natural number, and this step includes:

[0056] Connect the negative pole of the magnetic power supply to the first phase coil, the positive pole of the magnetic power supply to the second phase coil, fix the relative position of the armature coil and the permanent magnet, and then pass a pulse current into the armature coil based on the magnetic power supply.

[0057] For example, refer to Figure 2 and Figure 3 As shown, n=4, the number of stator slots in the brushless DC motor is 12, the number of rotor poles is 8, that is, there are 8 permanent magnets, and the armature coils on the stator are connected in a triangle. There are three groups of armature coils on the stator, divided into U-phase coils, V-phase coils and W-phase coils. There are 4 coils in each group of armature coils, the U-phase coil is divided into U1, U2, U3, U4 coils, the V-phase coil is divided into V1, V2, V3, V4 coils, and the W-phase coil is divided into W1, W2, W3, W4 coils.

[0058] The negative pole of the magnetizing power supply is connected to the U-phase coil terminal of the first phase, the positive pole of the magnetizing power supply is connected to the W-phase coil terminal of the second phase, and the V-phase coil terminal of the third phase is open. The red center line of any one of the 8 unmagnetized permanent magnets is facing the U-phase coil, and the green center line of the adjacent permanent magnet is facing the middle position of the V-phase coil and the W-phase coil. After fixing the position of the rotor so that the relative position of the armature coil and the permanent magnet is fixed and cannot be moved, turn on the magnetizing power supply to pass pulse current into the U-phase coil and the W-phase coil.

[0059] The three groups of armature coils in the brushless DC motor are connected in a Y-shaped connection, 3n armature coils are evenly spaced on the stator of the brushless DC motor, the permanent magnet rotor has 2n magnetic poles, n is a natural number, and this step includes:

[0060] Connect the negative pole of the magnetic power supply to the first phase coil, the positive pole of the magnetic power supply to the second phase coil and the third phase coil, fix the relative position of the armature coil and the permanent magnet, and then pass a pulse current into the armature coil based on the magnetic power supply.

[0061] For example, refer to Figure 2 and Figure 4 As shown, n=4, the number of stator slots in the brushless DC motor is 12, the number of rotor poles is 8, that is, there are 8 permanent magnets, and the armature coils on the stator are connected by Y-type wiring. There are three groups of armature coils on the stator, divided into U-phase coils, V-phase coils and W-phase coils. There are 4 coils in each group of armature coils, the U-phase coil is divided into U1, U2, U3, U4 coils, the V-phase coil is divided into V1, V2, V3, V4 coils, and the W-phase coil is divided into W1, W2, W3, W4 coils.

[0062] The negative pole of the magnetizing power supply is connected to the U-phase coil terminal of the first phase, and the positive pole of the magnetizing power supply is connected to the W-phase coil terminal of the second phase and the V-phase terminal of the third phase. The red center line of any one of the 8 unmagnetized permanent magnets is facing the U-phase coil, and the green center line of the adjacent permanent magnet is facing the middle position of the V-phase coil and the W-phase coil. After fixing the position of the rotor so that the relative position of the armature coil and the permanent magnet is fixed and cannot be moved, turn on the magnetizing power supply to pass pulse current into the U-phase coil, V-phase coil and W-phase coil.

[0063] S130, exchanging the connection direction of the positive and negative poles of the magnetic power source to reorganize the connection between the magnetic power source and the armature coil, and adjusting the relative position of the armature coil and the permanent magnet by relatively rotating the mechanical angle by a preset angle.

[0064] Specifically, the positive and negative connection directions of the magnetizing power supply can be exchanged by directly reversing the power polarity of the magnetizing power supply, or by splitting and exchanging the positive and negative power lines of the magnetizing power supply with the correspondingly connected armature coils. In the present application, after the positive power line, the negative power line and the connected armature coil of the magnetizing power supply are split, the positive power line is connected to the armature coil connected to the original negative power line, and the negative power line is connected to the first phase coil connected to the circular positive power line to exchange the positive and negative power lines of the magnetizing power supply, which is more convenient to operate.

[0065] Specifically, when the three groups of armature coils in the brushless DC motor are connected in a triangle connection, the connection between the magnetic power supply and the armature coils is reorganized including:

[0066] Separate the negative pole of the magnetic power supply and the first phase coil, and the positive pole of the magnetic power supply and the second phase coil;

[0067] The negative pole of the magnetic power supply is connected to the second phase coil, and the positive pole of the magnetic power supply is connected to the first phase coil.

[0068] Separate the negative pole of the magnetizing power supply from the U-phase coil terminal of the first phase that was originally connected, separate the positive pole of the magnetizing power supply from the terminal of the W-phase coil of the second phase that was originally connected, reconnect the negative pole of the magnetizing power supply to the terminal of the W-phase coil of the second phase, reconnect the positive pole of the magnetizing power supply to the terminal of the U-phase coil of the first phase, and open the V-phase coil terminal of the third phase. The wiring position is as follows: Figure 6 As shown. With the preset angle of relative rotation of the mechanical angle being 180° / n=180° / 4=45°, the permanent magnet rotor is rotated 45°. At this time, the permanent magnet facing the red center line of the U phase in the first magnetization rotates to the middle position of the V phase coil and the W phase coil, and the permanent magnet facing the green center line of the middle position of the V phase coil and the W phase coil in the first magnetization rotates to the center position of the U phase coil. After the rotation is completed, the relative position of the armature coil and the permanent magnet is fixed as shown in Figure 5 shown.

[0069] When the three sets of armature coils in the brushless DC motor are connected in a Y-type connection, the connection between the magnetic power supply and the armature coils is reorganized as follows:

[0070] Separate the negative pole of the magnetic power supply and the first phase coil, and the positive pole of the magnetic power supply and the second phase coil and the third phase coil;

[0071] The positive pole of the magnetic power supply is connected to the first phase coil, and the negative pole of the magnetic power supply is connected to the second phase coil and the third phase coil.

[0072] Separate the negative pole of the magnetizing power supply from the U-phase coil terminal of the first phase that was originally connected, separate the positive pole of the magnetizing power supply from the W-phase coil terminal of the second phase that was originally connected and the V-phase coil terminal of the third phase, reconnect the negative pole of the magnetizing power supply to the W-phase coil terminal of the second phase and the V-phase coil terminal of the third phase, and reconnect the positive pole of the magnetizing power supply to the U-phase coil terminal of the first phase. The wiring positions are as follows: Figure 7 As shown. With the preset angle of relative rotation of the mechanical angle being 180° / n=180° / 4=45°, the permanent magnet rotor is rotated 45°. At this time, the permanent magnet facing the red center line of the U phase in the first magnetization rotates to the middle position of the V phase coil and the W phase coil, and the permanent magnet facing the green center line of the middle position of the V phase coil and the W phase coil in the first magnetization rotates to the center position of the U phase coil. After the rotation is completed, the relative position of the armature coil and the permanent magnet is fixed as shown in Figure 5 shown.

[0073] S140, implementing a second magnetization of the permanent magnet, including: supplying a pulse current to the armature coil based on a magnetizing power supply.

[0074] In some embodiments, the magnetizing power supply is connected to the armature coil through a wiring harness, and the wiring harness is connected to an ammeter that monitors and displays the pulse current output by the magnetizing power supply. Since the display value of the magnetizing power supply is too rough, and the length, cross-sectional area, material, etc. of the wiring harness connected to the armature coil will affect the impedance of the current loop, thereby interfering with the actual current value flowing through the armature coil and making it impossible to obtain an accurate value, an ammeter is added to accurately monitor the size of the pulse current.

[0075] The rotor of the brushless DC motor is connected to a locking structure for locking the rotor through a reducer. The locking structure is connected to the rotor shaft of the brushless DC motor to achieve locking and rotation functions, and can fix the relative position of the permanent magnet and the armature coil before the pulse current is passed through the first and second magnetization of the permanent magnet, and drive the permanent magnet to rotate relative to the armature coil at a preset mechanical angle before the second magnetization of the permanent magnet. By adding a reducer (1:200) between the locking structure and the rotor shaft of the brushless DC motor, when the flux linkage value between the stator and the rotor of the brushless DC motor is tested using a flux tester after the permanent magnet is magnetized, the rotor can be rotated at a uniform and sufficiently slow speed to avoid the induced voltage generated by the rotating rotor from impacting the instrument circuit and causing damage.

[0076] In some embodiments, after performing the second magnetization of the permanent magnet, the method further comprises:

[0077] S150, judging whether the magnetization of the permanent magnet is saturated, including:

[0078] The output voltage of the magnetizing power supply is increased at equal intervals to repeatedly magnetize the permanent magnet, wherein the magnetization of the permanent magnet includes a first magnetization of the permanent magnet and a second magnetization of the permanent magnet;

[0079] Record the magnetic flux value and current value during the first magnetization and the second magnetization of the permanent magnet in each magnetization;

[0080] Reference Figure 8 As shown, if the magnetic flux value remains unchanged when the output voltage of the magnetizing power supply increases, it is determined that the permanent magnet is magnetized saturated.

[0081] One or more of the above-mentioned embodiments of the present application have at least one or more of the following beneficial effects: it can be applicable to the stator magnetization of brushless DC motors with delta connection and Y connection, avoids the mistaken application of the stator magnetization method of Y connection to the magnetization operation of the stator with delta connection, can solve the current problem of poor magnetization of brushless DC motors with delta connection, and allows the motors of high-voltage platforms to continue to use the built-in combined magnetization method.

[0082] The magnetizing device of brushless DC motor is as follows Fig. 9As shown, the magnetizing power supply includes an AC power supply that provides industrial AC voltage, i.e., an alternating current power supply. The industrial AC voltage is converted into a variable DC voltage, i.e., a variable direct current voltage, through a rectifier circuit. In addition, the magnetizing power supply also includes an adjustable capacitor, which is charged by a switch action. The adjustable capacitor can adjust the capacitance in a series-parallel form, so that the magnetizing voltage output by the magnetizing power supply can be changed according to actual conditions. The adjustment formula is W=1 / 2×C×U^2, where W refers to the required energy, C refers to the magnetic capacitance, and U refers to the magnetic voltage. The magnetizing power supply and the armature coil of the brushless DC motor are connected through a wiring harness. At this time, a release pulse current can be passed into the brush coil through a switch action, so that the armature coil generates an armature magnetic field to magnetize the permanent magnet.

[0083] Regarding the magnetization of the brushless DC motor with triangle connection Fig.10 As shown, taking the brushless DC motor with a triangle connection when n=2 as an example, it has 6 slots and 4 poles, that is, the number of stator slots in the brushless DC motor is 6, the number of rotor poles is 4, and there are 4 permanent magnets. Among the three groups of armature coils on the stator, the U phase coil is composed of U1 and U2 coils connected in series, the W phase coil is composed of W1 and W2 coils connected in series, and the V phase coil is composed of V1 and V2 coils connected in series. When the power is on, the currents I in the six coils are: 1, -0.5, -0.5, 1.0, -0.5, -0.5; When W is powered on, the currents I in the six coils are: 1.0, 0.0, 1.0, 1.0, 0.0, 1.0, The currents in the coils that are energized by W cancel each other out and no effective magnetic field can be generated.

[0084] About the Y-type wire brushless DC motor power magnetization Fig.11 As shown, taking the brushless DC motor with Y-type connection when n=2 as an example, it has 6 slots and 4 poles, that is, the number of stator slots in the brushless DC motor is 6, the number of rotor poles is 4, and there are 4 permanent magnets. Among the three groups of armature coils on the stator, the U phase coil is composed of U1 and U2 coils connected in series, the W phase coil is composed of W1 and W2 coils connected in series, and the V phase coil is composed of V1 and V2 coils connected in series. When the power is on, the currents I in the six coils are: 1, -1, 0.0, 1.0, -1, 0.0; When W is energized, the currents I in the six coils are: 1, -0.5, -0.5, 1.0, -0.5, -0.5; Turning on power does not guarantee that current can flow through each armature coil to generate an armature magnetic field to magnetize the permanent magnet.

[0085] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0086] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0087] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A method for magnetizing a brushless DC motor, characterized in that: The stator in the brushless DC motor has three groups of armature coils, and a permanent magnet rotor arranged opposite to the stator is internally matched, and the method includes: Taking any one of the stator slots as a starting point, defining the armature coil on the stator as a first phase coil, a second phase coil and a third phase coil in sequence; Implementing the first magnetization of the permanent magnet includes: connecting the negative pole of the magnetizing power supply with the first phase coil, the positive pole of the magnetizing power supply with at least one of the second phase coil and the third phase coil, fixing the relative position of the armature coil and the permanent magnet, and then passing a pulse current into the armature coil based on the magnetizing power supply; Reversing the connection direction of the positive and negative poles of the magnetizing power supply to reorganize the connection between the magnetizing power supply and the armature coil, and adjusting the relative position of the armature coil and the permanent magnet by relatively rotating the armature coil by a preset angle at a mechanical angle; Implementing the second magnetization of the permanent magnet includes: supplying a pulse current to the armature coil based on the magnetization power supply.

2. The method for magnetizing a brushless DC motor according to claim 1, characterized in that: The three groups of armature coils form a three-phase delta connection, 3n armature coils are evenly spaced on the stator of the brushless DC motor, and the permanent magnet rotor has 2n magnetic poles, where n is a natural number.

3. The method for magnetizing a brushless DC motor according to claim 2, characterized in that: The first magnetization of the permanent magnet includes: connecting the negative pole of the magnetizing power supply with the first phase coil, the positive pole of the magnetizing power supply with the second phase coil, fixing the relative position of the armature coil and the permanent magnet, and then passing a pulse current into the armature coil based on the magnetizing power supply.

4. The method for magnetizing a brushless DC motor according to claim 3, characterized in that: The step of changing the connection direction of the positive and negative poles of the magnetizing power supply to reorganize the connection between the magnetizing power supply and the armature coil includes: Separate the negative pole of the magnetizing power supply and the first phase coil, and separate the positive pole of the magnetizing power supply and the second phase coil; The negative pole of the magnetizing power supply is connected to the second phase coil, and the positive pole of the magnetizing power supply is connected to the first phase coil.

5. The method for magnetizing a brushless DC motor according to claim 1, characterized in that: The three groups of armature coils form a three-phase Y-type connection, 3n armature coils are evenly spaced on the stator of the brushless DC motor, and the permanent magnet rotor has 2n magnetic poles, where n is a natural number.

6. The method for magnetizing a brushless DC motor according to claim 5, characterized in that: The first magnetization of the permanent magnet comprises: The negative pole of the magnetic power supply is connected to the first phase coil, the positive pole of the magnetic power supply is connected to the second phase coil and the third phase coil, and after the relative position of the armature coil and the permanent magnet is fixed, a pulse current is passed into the armature coil based on the magnetic power supply.

7. The method for magnetizing a brushless DC motor according to claim 6, characterized in that: The step of changing the connection direction of the positive and negative poles of the magnetizing power source to reorganize the connection between the magnetizing power source and the armature coil includes: Separate the negative pole of the magnetizing power supply and the first phase coil, the positive pole of the magnetizing power supply and the second phase coil and the third phase coil; The positive pole of the magnetizing power supply is connected to the first phase coil, and the negative pole of the magnetizing power supply is connected to the second phase coil and the third phase coil.

8. The method for magnetizing a brushless DC motor according to any one of claims 2 to 7, characterized in that: The adjusting the relative positions of the countless armature coils and the permanent magnets by relatively rotating them at a preset mechanical angle comprises: The relative positions of the armature coil and the permanent magnet are adjusted by relative rotation of the mechanical angle of 180° / n.

9. The method for magnetizing a brushless DC motor according to claim 1, characterized in that: The magnetizing power supply is connected to the armature coil via a wiring harness, and the wiring harness is connected to an ammeter for monitoring and displaying the pulse current output by the magnetizing power supply; The rotor of the brushless DC motor is connected to a locking structure for locking the rotor through a reducer.

10. The method for magnetizing a brushless DC motor according to claim 1, characterized in that: After performing the second magnetization of the permanent magnet, the method further comprises: Determining whether the magnetization of the permanent magnet is saturated includes: The output voltage of the magnetizing power supply is increased at equal intervals to repeatedly magnetize the permanent magnet, wherein the magnetization of the permanent magnet includes a first magnetization of the permanent magnet and a second magnetization of the permanent magnet; Recording the magnetic flux value and the current value during the first magnetization and the second magnetization of the permanent magnet in each magnetization; If the magnetic flux value remains unchanged when the output voltage of the magnetizing power supply increases, it is determined that the magnetization saturation of the permanent magnet is reached.

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