A multi-pole outer rotor permanent magnet brushless motor

Abstract

The application provides a multi-pole outer rotor permanent magnet brushless motor, which adopts a specific driving mode and a permanent magnet brushless motor with a multiple of 16 of the number of magnetic poles on the outer rotor and a multiple of 15 of the number of slots of the inner stator, and can supply power to two-phase windings and simultaneously supply power to three-phase windings in each driving state, so that the motor can save power under light load and meet normal operation under heavy load when the load greatly changes, and the motor torque, power density and efficiency are improved under the condition of energy saving. The winding is made in a concentrated manner on the armature teeth of the disc-shaped inner stator, the magnetic lines generated by the winding are perpendicular to the motor rotating shaft, and the magnetic lines generated by the magnetic poles on the outer rotor are also perpendicular to the motor rotating shaft. The motor manufacturing process and cost are the same as those of the conventional outer rotor permanent magnet brushless motor of the same type, but the performance of the three-phase outer rotor permanent magnet brushless motor is greatly improved. The motor has wide application prospects in new energy electric two-wheeled motorcycles, electric four-wheeled vehicles, unmanned aerial vehicles and robot bionic joints and other industrial applications.

Description

[0001] This invention discloses a multi-pole external rotor permanent magnet brushless motor, including an external rotor permanent magnet brushless motor and a matching brushless motor driver circuit. Technical Field

[0002] This invention relates to the field of external rotor permanent magnet brushless motors and brushless motor driver circuit technology. Background technology:

[0003] A brushless motor consists of a motor body and a driver circuit, and is a typical mechatronics product.

[0004] Almost all external rotor permanent magnet brushless motors energize the two-phase windings connected in series simultaneously in every driving state. The utilization rate of the windings is low, at 2 / 3 = 66.6%, which is not conducive to improving the motor torque and power. Summary of the Invention

[0005] This invention provides a multi-pole external rotor permanent magnet brushless motor. Employing a different driving method and specific concentrated windings than traditional methods, this external rotor permanent magnet brushless motor with 16 magnetic poles (or multiples thereof) on the external rotor and 15 slots (or multiples thereof) on the inner stator can simultaneously energize two-phase windings and three-phase windings in every driving state. This satisfies the motor's characteristics of being able to operate energy-savingly under light loads and operating normally under heavy loads when the load changes significantly, meeting various working conditions. Furthermore, it improves motor torque, power density, and efficiency while saving energy. This invention employs a concentrated winding method on the armature teeth of the inner stator, where five coils of the same winding coil on the same phase are wound in opposite directions on adjacent armature teeth, and two adjacent sets of winding coils on the same phase are wound in the same direction, spaced 10 armature teeth apart. A concentrated winding method is also used, where five adjacent armature teeth are placed on adjacent winding coils of different phases. This generates a specific rotating magnetic field in the stator, which interacts with the magnetic poles on the rotor, producing completely different motor performance. Furthermore, the specific driving method we developed allows all three phase windings to be energized in every driving state, increasing the winding coil utilization rate from 66.6% to 100%, thus improving torque and power density. This significantly enhances the performance of the three-phase external rotor permanent magnet brushless motor. It has broad application prospects in new energy electric two-wheeled motorcycles, as well as in industrial applications such as drones and bionic joints for robots.

[0006] The present invention discloses a multi-pole external rotor permanent magnet brushless motor. The motor is manufactured as follows: the inner stator of the permanent magnet brushless motor winding is a disc-shaped structure with magnetically conductive material such as silicon steel sheets for the armature teeth and armature slots used for winding the winding. When the winding coil is energized, it generates magnetic lines of force perpendicular to the motor shaft. The outer rotor is composed of U-shaped discs filled with permanent magnets installed radially on the inner side. The magnetic lines of force of the permanent magnets are perpendicular to the motor shaft. The number of magnetic poles on the outer rotor is greater than the number of teeth on the inner stator armature, making it a radial magnetic field motor type.

[0007] The present invention discloses a multi-pole external rotor permanent magnet brushless motor, the driver circuit of which consists of an adjustable PWM pulse width modulator for controlling the speed, implemented by a microcontroller MCU, and an H-bridge power driver (generally a high-power MOSFET or IGBT composite fully controlled voltage-driven power semiconductor device module) that drives the coils of each phase winding. Attached Figure Description

[0008] Figure 1 The diagram shows the structure of the outer rotor U2 and inner stator U1 of a multi-pole external rotor permanent magnet brushless motor of the present invention, which is made of an outer rotor with 32 magnetic poles and an inner stator with 30 slots.

[0009] Figure 3 This is a winding diagram of the inner stator U1, which is made with 32 magnetic poles on the outer rotor and 30 slots on the inner stator, and is wound in a concentrated winding manner. The arrows on the coils wound on the armature teeth indicate the winding direction of the coils on the winding. When the current flows from A+ to A-, the magnetic pole polarity shown in the figure is generated on the stator armature teeth. 1 to 30 are the identification numbers of the armature teeth.

[0010] Figure 2 For clarity, only [the following is displayed] Figure 3 The winding diagram of the upper U-phase winding, where U1 and U2 are the endpoints of the winding.

[0011] Figure 4 This is a structural diagram of the outer rotor. U2 is the outer rotor, which consists of a U-shaped disk with permanent magnets mounted on its inner radial side. S1, N1, S2, and N2 are the north and south magnetic poles on the inner radial side. The magnetic poles of the permanent magnets are arranged with their north and south poles adjacent to each other, and their magnetic field lines are perpendicular to the shaft. The outer disk is a magnetically conductive ring on which the magnets are mounted and fixed. The motor shaft Z is located in the center of the disk, and it is perpendicular to and coaxial with the U-shaped disk.

[0012] Figures 5 to 10 This is a driving diagram showing the six driving states of this permanent magnet brushless motor during two-phase operation.

[0013] Figures 11 to 16 This is a driving diagram showing the six driving states of this permanent magnet brushless motor during three-phase operation.

[0014] Figure 17This is a schematic diagram of the structure of the outer rotor U2 and inner stator U1 of a multi-pole outer rotor permanent magnet brushless motor of the present invention, which is made of 16 magnetic poles on the outer rotor and 15 slots on the inner stator.

[0015] Figure 18 This is a control circuit diagram of its driver circuit using a microcontroller (MCU).

[0016] Figure 19 This is the power output circuit diagram of its driver circuit. Detailed Implementation

[0017] This invention discloses a multi-pole external rotor permanent magnet brushless motor. Its inner stator is disc-shaped with armature teeth and slots around its periphery for winding the coils. It is constructed using a magnetically conductive material such as laminated silicon steel sheets. The inner stator windings are wound in a concentrated manner around a single armature tooth, with adjacent coils of the same phase winding wound in opposite directions. The phase windings are placed adjacent to each other, and the magnetic lines of force generated by the stator windings are perpendicular to the motor shaft. The outer rotor is composed of a U-shaped disc with permanent magnets mounted radially inside. The magnetic lines of force of the permanent magnets mounted inside the U-shaped disc are perpendicular to the motor shaft. The outer rotor can also be composed of a ring of permanent magnets magnetized radially, with the magnetic poles of the permanent magnets arranged adjacently at north and south poles. The motor shaft is vertically connected to the outer rotor and located at the center of the outer rotor. The inner stator is fixed inside the U-shaped disc of the outer rotor and coaxial with the outer rotor. The number of permanent magnets on the outer rotor is 16 times a coefficient K, and the number of armature teeth on the inner stator is 15 times a coefficient K, where K is a positive integer greater than or equal to 1. Figure 1 As shown. The driver circuit uses a microcontroller (MCU) for control and an H-bridge power driver output. The start and end terminals of each phase winding are connected to the midpoint of the left and right arms of their respective H-bridge power drivers. The upper and lower control terminals of the left and right arms of each H-bridge power driver are controlled by four different signals, see [link to relevant documentation]. Figure 18 and Figure 19 The power drive device that energizes the winding is composed of IGBT composite fully controllable voltage-driven power semiconductor devices, or high-power MOSFETs and other high-power semiconductor power devices.

[0018] In brushless motors, for rotors equipped with permanent magnets, the position of the magnetic poles on the rotor is commonly detected using Hall effect sensors. Alternatively, a perforated disk can be mounted on the rotor shaft in conjunction with photoelectric elements for detection. A rotary transformer can also be used. There is also a Hall-less method that determines the rotor magnet position by detecting the zero-crossing point of the winding current. These are all common techniques for detecting the position of the magnetic poles on the permanent magnet rotor in brushless motors. Even Hall effect sensors are divided into three types: with latching, without latching, and with linear characteristics. This is not the fundamental principle of brushless motor research. For ease of understanding, the following will explain... Figures 5 to 19The driving principle and specific implementation method of a common Hall element with latching are explained.

[0019] Although this invention is defined as having 16 permanent magnets multiplied by a coefficient K on the outer rotor and 15 armature teeth multiplied by a coefficient K on the inner stator, where K is a positive integer greater than or equal to 1, in order to illustrate that the five concentrated coils of the same winding coil on the same phase use the opposite winding direction of adjacent armature teeth, and that the two adjacent windings on the same phase are wound in the same direction with a 10-tooth interval in between, we use the case of 32 permanent magnets when K=2 and 30 armature teeth on the inner stator for illustration.

[0020] The winding method of the inner stator coils is described below:

[0021] Figure 2 and Figure 3 The diagram shows a three-phase stator with 30 armature teeth wound in a centralized manner. The arrows on the windings in the diagram indicate the winding direction.

[0022] Depend on Figure 2 As can be seen, the U-phase winding starts from U1. The winding coil begins from the armature slot between armature teeth 1 and 2 and is wound clockwise around armature tooth 1 (with the observation point facing the armature tooth as the viewpoint). After reaching the required number of turns, it is wound counterclockwise around armature tooth 2. After reaching the required number of turns, it is wound clockwise around armature tooth 3. After reaching the required number of turns, it is wound counterclockwise around armature tooth 4. After reaching the required number of turns, it is wound clockwise around armature tooth 5. After reaching the required number of turns, the first group of coils is drawn out from the armature slot between armature teeth 4 and 5. Then, the coils are wound from the armature teeth... Starting from the armature slot between 16 and 17, wind the coil clockwise around armature tooth 16 (still using the viewpoint facing the armature tooth as the observation point). After reaching the required number of turns, wind counterclockwise around armature tooth 17. After reaching the required number of turns, wind clockwise around armature tooth 18. After reaching the required number of turns, wind counterclockwise around armature tooth 19. After reaching the required number of turns, wind clockwise around armature tooth 20. After reaching the required number of turns, the coil is led out from the armature slot between armature teeth 19 and 20 to form the second coil group, which is then led out as terminal U2. The two coil groups are now complete. The two coil groups should be wound according to... Figure 2 As shown, when DC current A+ flows through terminal U1 and DC current A- flows through terminal U2, six south poles and four north poles will be generated. Each coil group will generate two south poles S and north poles N with the same arrangement. The first group of coils will generate S, N, S, S, N in sequence, and the second group of coils will also generate S, N, S, N, S, meaning that the winding direction of adjacent coil groups is the same. Each group of coils is wound around 5 armature teeth, and the coils on adjacent armature teeth are wound in opposite directions. There are also 10 armature teeth between adjacent coil groups, which are used to wind another two phases. That is, there are 10 armature teeth between adjacent coil groups.

[0023] Depend on Figure 3 As can be seen, the V-phase winding starts from V1. The winding coil begins from the armature slot between armature teeth 6 and 7 and is wound clockwise (from the perspective of facing the armature teeth). After reaching the required number of turns, it is wound counterclockwise around armature tooth 7. After reaching the required number of turns, it is wound clockwise around armature tooth 8. After reaching the required number of turns, it is wound counterclockwise around armature tooth 9. After reaching the required number of turns, it is wound clockwise around armature tooth 10. After reaching the required number of turns, the first group of coils is drawn out from the armature slot between armature teeth 9 and 10. Then, the first group of coils is drawn out from armature teeth 20 and 21. The armature slots are first wound clockwise around armature tooth 21 (still with the viewpoint facing the armature tooth as the observation point). After the required number of turns, the coils are wound counterclockwise around armature tooth 22. After the required number of turns, the coils are wound clockwise around armature tooth 23. After the required number of turns, the coils are wound counterclockwise around armature tooth 24. After the required number of turns, the coils are wound clockwise around armature tooth 25. After the required number of turns, the coils are led out from the armature slot between armature teeth 24 and 25 to form the second set of coils. After the two sets of coils are wound, the coils are led out from the armature slot between armature teeth 24 and 55 to form the V2 end.

[0024] Depend on Figure 3 As can be seen, the W-phase winding starts from W1. The winding coil begins from the armature slot between armature teeth 11 and 12 and is wound clockwise (from the perspective of facing the armature teeth). After reaching the required number of turns, it is wound counterclockwise around armature tooth 12, then clockwise around armature tooth 13, then counterclockwise around armature tooth 14, then clockwise around armature tooth 15. After reaching the required number of turns, the first coil is drawn out from the armature slot between armature teeth 14 and 15, and then from armature tooth 26... Starting from the middle armature slot of 27, wind around armature tooth 26 in a clockwise direction (still with the viewpoint facing the armature tooth as the observation point). After winding to the required number of turns, wind around armature tooth 27 in a counterclockwise direction. After winding to the required number of turns, wind around armature tooth 28 in a counterclockwise direction. After winding to the required number of turns, wind around armature tooth 29 in a counterclockwise direction. After winding to the required number of turns, wind around armature tooth 30 in a counterclockwise direction. After winding to the required number of turns, the second set of coils is led out from the middle armature slot of armature teeth 29 and 30. After the two sets of coils are wound, the W2 end is led out from the middle armature slot of armature teeth 29 and 30.

[0025] As can be seen from the above, the stator winding of a multi-pole external rotor permanent magnet brushless motor is wound in the following way: the inner stator winding adopts a concentrated winding method to wind the coil around a single armature tooth. There are a total of 5 concentrated coils in the same winding coil on the same phase, and the coils of adjacent armature teeth are wound in opposite directions. The two adjacent windings on the same phase are wound in the same direction, and are placed with a gap of 10 armature teeth in between. The three-phase windings are arranged in a manner that the windings of adjacent phases are placed with a gap of five armature teeth to form the first, second and third phase windings.

[0026] In this invention, the number of permanent magnets on the outer rotor is greater than the number of armature teeth on the inner stator. The relationship between the number of permanent magnet poles on the inner radial direction of the U-shaped disk on the outer rotor and the number of armature teeth on the inner stator is as follows: the number of permanent magnets on the outer rotor is 16 times a coefficient K, and the number of armature teeth on the inner stator is 15 times a coefficient K, where K is a positive integer greater than or equal to 1. When the coefficient K = 1, there are 16 permanent magnets on the outer rotor and 15 armature teeth on the inner stator, with each phase winding having one set of 5 coils wound in a concentrated manner. When the coefficient K = 2, there are 32 permanent magnets on the outer rotor and 30 armature teeth on the inner stator, with each phase winding having two sets of 5 coils wound in a concentrated manner. The coils are manufactured in a specific manner. When the coefficient K = 3, there are 48 permanent magnets on the outer rotor and 45 armature teeth on the inner stator. Each phase winding has three groups of five coils wound in a concentrated manner. When the coefficient K = 4, there are 64 permanent magnets on the outer rotor and 60 armature teeth on the inner stator. Each phase winding has four groups of five coils wound in a concentrated manner, and so on. When the coefficient K is greater than 3, the number of permanent magnets on the outer rotor can be reduced or increased by one south pole and one north pole, for a total of two permanent magnets (one south pole and one north pole; reducing or increasing is to adjust torque pulsation to adapt to different needs) without significantly affecting its performance. When K is less than or equal to 3, the magnetic poles cannot be added or removed.

[0027] The driving circuit of this invention consists of Figure 18 and Figure 19 Composition, in Figure 18 SW1 is the rotary forward / reverse switch, and SW2 is the start / stop switch. IC4 is a circuit that generates a voltage +15V higher than the operating voltage V to supply power. Figure 19 IGBTs are used in China. Figure 18 IC1 in the code is the MCU, whose built-in program provides corresponding drives when the three Hall sensors HA, HB, and HC are in different states. V1 is for speed regulation, which causes the MCU to output a pulse width modulation (PWM) signal with a duty cycle to regulate the motor speed. Figure 19As can be seen, the power driving device for each phase winding consists of an H-bridge power driver composed of two sets of series-connected composite fully controllable voltage-driven power semiconductor devices (IGBTs) forming the left arm and another two sets of series-connected composite fully controllable voltage-driven power semiconductor devices (IGBTs) forming the right arm. The start and end points of each phase winding are connected to the midpoint of the left and right arms of their respective H-bridge power drivers. The upper and lower control terminals of the left and right arms of each H-bridge power driver are controlled by four different signals. The three H-bridge power drivers are controlled by a total of 12 different signals. The power driving device can also be a high-power MOSFET.

[0028] In almost all traditional brushless motor drives, each driving state involves energizing two of the three-phase windings connected in series and switching them alternately to generate a rotating magnetic field, thereby driving the motor rotor to rotate. This structural reason makes it impossible to simultaneously apply the same amount of current to all three phases. However, this invention employs a specific driving method developed to allow simultaneous energization of two to three phase windings under varying load conditions. Under normal load conditions, two phases are energized, while under heavy load conditions, all three phases are energized to ensure operation. When the three-phase windings are energized, the utilization rate of the winding coils reaches 100%. The increased input energy to the stator windings enhances the magnetic field generated by the stator and provides a greater driving force to the rotor magnetic field, improving the brushless motor's torque and power density. However, this cannot be achieved using traditional brushless motor drivers and must be implemented using the driver developed in this invention. This is why this invention's multi-pole external rotor permanent magnet brushless motor involves not only the research and reconstruction of the motor itself but also the research and reconstruction of its driver. This is also why they are inseparable and must be patented together; only by combining the two can the functional characteristics of this invention be realized. For ease of analysis and explanation, we also consider the magnetic poles generated by the outer rotor and the inner stator winding when energized as equivalent to their midpoint, which is a commonly used method in electrodynamic analysis.

[0029] The above describes the structure of a multi-pole external rotor permanent magnet brushless motor according to the present invention. The following describes the driving mechanism of the motor and driver of the present invention in various driving states.

[0030] Figures 5 to 16 The arrows on the outer ends of the stator indicate the direction of current flow in each driving state. U and S on the stator armature teeth represent the north and south pole magnetism generated by the U-phase, V-phase, and W-phase windings on the armature teeth at this time. The lines inside the stator and rotor indicate the direction of force on the rotor's magnetic pole. The lines connecting the inner stator and outer rotor with the same magnetism represent the thrust of the inner stator to the outer rotor's magnetic pole, and the lines connecting the inner stator and outer rotor with opposite magnetism represent the pull of the inner stator to the outer rotor's magnetic pole. Their combined action causes the outer rotor to rotate.

[0031] The following describes the various driving states in which the two-phase windings are simultaneously energized. Figures 5 to 10 and Figure 18 , Figure 19 To describe:

[0032] In drive state 1, such as Figure 5 As shown, the output states of the three Hall sensors are HA=L, HB=H and HC=L; Figure 18 With SH5=L, SH1=L, and SL5 and SL1 outputting PWM waves, Figure 19 When transistors T7, T6, T1, and T4 are turned on, current flows into V2 and U1, and flows out through V1 and U2. This produces the following effect: Figure 5 The magnetic poles shown are as follows: teeth 24, 22, 9 and 7, where the V-phase winding is located, generate the south pole S, which pushes S13, S12, S5, and S4 on the outer rotor clockwise, and simultaneously pulls N13, N12, N5, and N4 on the outer rotor clockwise; teeth 25, 23 and 8, 6, where the V-phase winding is located, generate the north pole N, which pushes N13, N12, N4, and N3 on the outer rotor counterclockwise, and simultaneously pulls S13, S12, S5, and S4 on the outer rotor clockwise. Teeth 20, 18, 16 and teeth 5, 3, 1 of the U-phase winding generate the south pole (S), which pushes S11, S10, S9, S3, S2, S1 on the outer rotor clockwise, and simultaneously pulls N11, N10, N9, N3, N2, N1 on the outer rotor clockwise. Teeth 19, 17 and teeth 4, 2 of the U-phase winding generate the north pole (N), which pushes N10, N9, N2, N1 on the outer rotor clockwise, and simultaneously pulls S11, S10, S3, S2 on the outer rotor clockwise. Together, these generate 20 push forces and 18 pull forces clockwise, causing the outer rotor to rotate clockwise.

[0033] In drive state 2, such as Figure 6 As shown, the output states of the three Hall sensors are HA=L, HB=H and HC=H; Figure 18 With SH1=L, SH6=L, and SL1 and SL6 outputting PWM waves, Figure 19 When circuits T1, T4, T11, and T10 are turned on, current flows into U1 and W2, and flows out through U2 and W1. This produces the following: Figure 6The magnetic poles shown are as follows: teeth 20, 18, 16 and teeth 5, 3, 1 where the U-phase winding is located generate the south pole S, which pushes S11, S10, S9, S3, S2, S1 on the outer rotor clockwise, and at the same time pulls N10, N9, N2, N1 on the outer rotor clockwise; teeth 19, 17 and teeth 4, 2 where the U-phase winding is located generate the north pole N, which pushes N10, N9, N2, N1 on the outer rotor clockwise, and at the same time pulls S11, S10, S3, S2 on the outer rotor clockwise. Teeth 14, 12, 29, and 27 of the W-phase winding generate the south pole (S), which pushes S8, S7, S16, and S15 on the outer rotor clockwise, and simultaneously pulls N8, N7, N16, and N15 on the outer rotor clockwise. Teeth 15, 13, 11, 30, 28, and 26 of the W-phase winding generate the north pole (N), which pushes N8, N7, N6, N16, N15, and N14 on the outer rotor clockwise, and simultaneously pulls S9, S8, S7, S1, S16, and S15 on the outer rotor clockwise. Together, these generate 20 thrust forces and 18 pull forces clockwise, causing the outer rotor to rotate clockwise.

[0034] In drive state 3, such as Figure 7 As shown, the output states of the three Hall sensors are HA=L, HB=L and HC=H; Figure 18 With SH6=L, SH2=L, and SL6 and SL2 outputting PWM waves, Figure 19 When transistors T11, T10, T5, and T8 are conducting, current flows in through W2 and V1, and flows out through W1 and V2. This produces the following effect: Figure 7 The magnetic poles shown are as follows: teeth 14, 12 and teeth 29, 27, where the W-phase winding is located, generate the south pole S, which pushes S8, S7, S16, S15 on the outer rotor clockwise, and at the same time pulls N8, N7, N16, N15 on the outer rotor clockwise; teeth 15, 13, 11 and 30, 28, 26, where the W-phase winding is located, generate the north pole N, which pushes N8, N7, N6, N16, N15, N14 on the outer rotor clockwise, and at the same time pulls S8, S7, S16, S15 on the outer rotor clockwise. Teeth 10, 8, 6 and teeth 25, 23, 21 of the V-phase winding generate the south pole (S), which pushes S6, S5, S4, S14, S13, S12 on the outer rotor clockwise, while simultaneously pulling N6, N5, N4, N14, N13, N12 on the outer rotor clockwise. Teeth 9, 7 and teeth 24, 22 of the V-phase winding generate the north pole (N), which pushes N5, N4, N13, N12 on the outer rotor counterclockwise, while simultaneously pulling S6, S5, S14, S13 on the outer rotor clockwise. Together, these generate 20 thrust forces and 18 pull forces clockwise, causing the outer rotor to rotate clockwise.

[0035] In drive state 4, such as Figure 8 As shown, the output states of the three Hall sensors are HA=H, HB=L and HC=H; Figure 18With SH2=L, SH4=L, and SL2 and SL4 outputting PWM waves, Figure 19 When circuits T5, T8, T3, and T2 are turned on, current flows into V1 and U2, and flows out through V2 and U1. This produces the following effect: Figure 8 The magnetic poles shown, where the V-phase winding is located, 10, 8, 6 and 25, 23, 21 generate the south pole S, which pushes the outer rotor S6, S5, S4, S14, S13, S12 clockwise and pulls the outer rotor N5, N4, N13, N12 clockwise; the teeth 9, 7 and 24, 22 where the V-phase winding is located generate the north pole N, which pushes the outer rotor N5, N4, N13, N12 counterclockwise and pulls the outer rotor S6, S5, S14, S13 clockwise. Teeth 4, 2, 19, and 17 of the U-phase winding generate the south pole (S), which pushes S3, S2, S11, and S10 on the outer rotor clockwise, and simultaneously pulls N3, N2, N11, and N10 on the outer rotor clockwise. Teeth 5, 3, 1, 20, 18, and 16 of the U-phase winding generate the north pole (N), which pushes N3, N2, N1, N11, N10, and N9 on the outer rotor clockwise, and simultaneously pulls S4, S3, S2, S12, S11, and S10 on the outer rotor clockwise. Together, these generate 20 push forces and 18 pull forces clockwise, causing the outer rotor to rotate clockwise.

[0036] In drive state 5, such as Figure 9 As shown, the output states of the three Hall sensors are HA=H, HB=L and HC=L; Figure 18 With SH4=L, SH3=L, and SL4 and SL3 outputting PWM waves, Figure 19 When circuits T3, T2, T9, and T12 are turned on, current flows into U2 and W1, and flows out through U1 and W2. This produces the following effect: Figure 9 The magnetic poles shown are as follows: teeth 4, 2 and teeth 19, 17, where the U-phase winding is located, generate the south pole S, which pushes S3, S2, S11, S10 on the outer rotor clockwise, and simultaneously pulls N3, N2, N11, N10 on the outer rotor clockwise; teeth 5, 3, 1 and 20, 18, 16, where the U-phase winding is located, generate the north pole N, which pushes N3, N2, N1, N11, N10, N9 on the outer rotor clockwise, and simultaneously pulls S3, S2, S11, S10 on the outer rotor clockwise. Teeth 30, 28, 26 and teeth 15, 13, 11 of the W-phase winding generate the south pole (S), which pushes S1, S16, S15, S9, S8, S7 on the outer rotor clockwise, while simultaneously pulling N1, N16, N15, N9, N8, N7 on the outer rotor clockwise. Teeth 29, 27 and teeth 14, 12 of the W-phase winding generate the north pole (N), which pushes N16, N15, N8, N7 on the outer rotor clockwise, while simultaneously pulling S1, S16, S9, S8 on the outer rotor clockwise. Together, these generate 20 thrust forces and 18 pull forces clockwise, causing the outer rotor to rotate clockwise.

[0037] In drive state 6, such as Figure 10 As shown, the output states of the three Hall sensors are HA=H, HB=H and HC=L; Figure 18 With SH3=L, SH5=L, and SL3 and SL5 outputting PWM waves, Figure 19 When transistors T9, T12, T7, and T6 are turned on, current flows in through W1 and V2, and flows out through W2 and V1. This produces the following effect: Figure 10 The magnetic poles shown are as follows: teeth 30, 28, 26 and 15, 13, 11 where the W-phase winding is located generate the south pole S, which pushes S1, S16, S15, S9, S8, S7 on the outer rotor clockwise, and at the same time pulls N16, N15, N8, N7 on the outer rotor clockwise; teeth 29, 27 and 14, 12 where the W-phase winding is located generate the north pole N, which pushes N16, N15, N8, N7 on the outer rotor clockwise, and at the same time pulls S1, S16, S9, S8 on the outer rotor clockwise. Teeth 24, 22 and teeth 9, 7 of the V-phase winding generate the south pole (S), which pushes S14, S13, S6, and S5 of the outer rotor clockwise, and simultaneously pulls N14, N13, N6, and N5 of the outer rotor clockwise. Teeth 25, 23, 21 and teeth 10, 8, and 6 of the V-phase winding generate the north pole (N), which pushes N14, N13, N12, N6, N5, and N4 of the outer rotor counterclockwise, and simultaneously pulls S15, S14, S13, S7, S6, and S5 of the outer rotor clockwise. Together, these generate 20 thrust forces and 18 pull forces clockwise, causing the outer rotor to rotate clockwise.

[0038] After the above six driving states, a 360-degree electrical rotation is completed. However, for a mechanical angle of 360 degrees, since the outer rotor has 16 pairs of magnetic poles, the mechanical angle of rotation is 360 / 16 = 22.5 degrees. The angle of rotation in each driving state is 22.5 / 6 = 3.75 degrees. The six driving processes are then repeated to rotate the outer rotor of the motor. As can be seen above, the total thrust and pull force in each driving state is 38.

[0039] The following describes the various driving states in which all three phase windings are simultaneously energized. Figures 11 to 16 and Figure 18 , Figure 19 To describe:

[0040] In drive state 1, such as Figure 11 As shown, the output states of the three Hall sensors are HA=L, HB=H and HC=L; Figure 18 When SH5=L, SH1=L, SH6=L, and SL5, SL1, and SL6 output PWM waves, Figure 19 When circuits T7, T6, T1, T4, T11, and T10 are turned on, current flows into V2, U1, and W2, and flows out through V1, U2, and W1. This produces the following effect: Figure 11 The magnetic poles shown are as follows: teeth 29, 27 and teeth 14, 12 where the W-phase winding is located generate the south pole S, which pushes S16, S15 and S8, S7 on the outer rotor clockwise, and at the same time pulls N16, N15, N8, N7 on the outer rotor clockwise; teeth 30, 28 and teeth 15, 13 where the W-phase winding is located generate the north pole N, which pushes N16, N15, N8, N7 on the outer rotor clockwise, and at the same time pulls S1, S16, S9, S8 on the outer rotor clockwise. Teeth 24, 22, 9 and 7 of the V-phase winding generate the south pole S, which pushes S13, S12, S5 and S4 on the outer rotor clockwise, and at the same time pulls N13, N12, N5 and N4 on the outer rotor clockwise; Teeth 23, 21 and 8 and 6 of the V-phase winding generate the north pole N, which pushes N12, N11, N4 and N3 on the outer rotor counterclockwise, and at the same time pulls S13, S12, S5 and S4 on the outer rotor clockwise. Teeth 20, 18, 16 and teeth 5, 3, 1 of the U-phase winding generate the south pole (S), which pushes S11, S10, S9, S3, S2, S1 on the outer rotor clockwise, and simultaneously pulls N11, N10, N9, N9, N3, N2, N1 on the outer rotor clockwise. Teeth 19, 17 and teeth 4, 2 of the U-phase winding generate the north pole (N), which pushes N10, N9, N2, N1 on the outer rotor clockwise, and simultaneously pulls S11, S10, S3, S2 on the outer rotor clockwise. Together, these generate 26 push and 26 pull forces clockwise, causing the outer rotor to rotate clockwise.

[0041] In drive state 2, such as Figure 12 As shown, the output states of the three Hall sensors are HA=L, HB=H and HC=H; Figure 18 When SH1=L, SH6=L, SH2=L, SL1, SL6 and SL2 output PWM waves, Figure 19 When circuits T1, T4, T11, T10, T5, and T8 are turned on, current flows into U1, W2, and V1, and flows out through U2, W1, and V2. This produces the following: Figure 12The magnetic poles shown are as follows: teeth 25, 23 and teeth 10, 8, where the V-phase winding is located, generate the south pole S, which pushes S14, S13, S6, S5 on the outer rotor clockwise, and at the same time pulls N14, N13, N6, N5 on the outer rotor clockwise; teeth 24, 22 and teeth 9, 7, where the V-phase winding is located, generate the north pole N, which pushes N13, N12, N5, N4 on the outer rotor counterclockwise, and at the same time pulls S14, S13, S6, S5 on the outer rotor clockwise. Teeth 18, 16 and teeth 3, 1 of the U-phase winding generate the south pole S, which pushes S10, S9, S2, S1 on the outer rotor clockwise, and at the same time pulls N10, N9, N2, N1 on the outer rotor clockwise; Teeth 19, 17 and teeth 4, 2 of the U-phase winding generate the north pole N, which pushes N10, N9, N2, N1 on the outer rotor clockwise, and at the same time pulls S11, S10, S3, S2 on the outer rotor clockwise. Teeth 14, 12, 29, and 27 of the W-phase winding generate the south pole (S), which pushes S8, S7, S16, and S15 on the outer rotor clockwise, and simultaneously pulls N8, N7, N16, and N15 on the outer rotor clockwise. Teeth 15, 13, 11, 30, 28, and 26 of the W-phase winding generate the north pole (N), which pushes N8, N7, N6, N16, N15, and N14 on the outer rotor clockwise, and simultaneously pulls S9, S8, S7, S1, S16, and S15 on the outer rotor clockwise. Together, these generate 26 clockwise thrusts and 26 clockwise pulls, causing the outer rotor to rotate clockwise.

[0042] In drive state 3, such as Figure 13 As shown, the output states of the three Hall sensors are HA=L, HB=L and HC=H; Figure 18 In the configuration of SH6=L, SH2=L, SH4=L, SL6, SL2 and SL4 output PWM waves to make Figure 19 When circuits T11, T10, T5, T8, T3, and T2 are turned on, current flows in through W2, V1, and U2, and flows out through W1, V2, and W1. This produces the following effect: Figure 13The magnetic poles shown are as follows: teeth 19, 17 and teeth 4, 2 where the U-phase winding is located generate the south pole S, which pushes S11, S10, S3, S2 on the outer rotor clockwise, and at the same time pulls N11, N10, N3, N2 on the outer rotor clockwise; teeth 20, 18 and teeth 5, 3 where the U-phase winding is located generate the north pole N, which pushes N11, N10, N3, N2 on the outer rotor clockwise, and at the same time pulls S12, S11, S4, S3 on the outer rotor clockwise. Teeth 14, 12 and 29, 27 of the W-phase winding generate the south pole S, which pushes S8, S7, S16, S15 on the outer rotor clockwise, and at the same time pulls N8, N7, N16, N15 on the outer rotor clockwise; Teeth 13, 11 and 28, 26 of the W-phase winding generate the north pole N, which pushes N7, N6, N15, N14 on the outer rotor clockwise, and at the same time pulls S8, S7, S16, S15 on the outer rotor clockwise. Teeth 10, 8, 6 and teeth 25, 23, 21 of the V-phase winding generate the south pole (S), which pushes S6, S5, S4, S14, S13, S12 on the outer rotor clockwise, while simultaneously pulling N6, N5, N4, N14, N13, N12 on the outer rotor clockwise. Teeth 9, 7 and teeth 24, 22 of the V-phase winding generate the north pole (N), which pushes N5, N4, N13, N12 on the outer rotor counterclockwise, while simultaneously pulling S6, S5, S14, S13 on the outer rotor clockwise. Together, these generate 26 clockwise thrusts and 26 clockwise pulls, causing the outer rotor to rotate clockwise.

[0043] In drive state 4, such as Figure 14 As shown, the output states of the three Hall sensors are HA=H, HB=L and HC=H; Figure 18 In the configuration of SH2=L, SH4=L, SH3=L, SL2, SL4 and SL3 output PWM waves to make Figure 19 When circuits T5, T8, T3, T2, T9, and T12 are turned on, current flows into V1, U2, and W1, and flows out through V2, U1, and W2. This produces the following effect: Figure 14The magnetic poles shown are as follows: teeth 15, 13 and teeth 30, 28, where the W-phase winding is located, generate the south pole S, which pushes S9, S8, S1, and S16 on the outer rotor clockwise, and at the same time pulls N9, N8, N1, and N16 on the outer rotor clockwise; teeth 14, 12 and teeth 29, 27, where the W-phase winding is located, generate the north pole N, which pushes N8, N7, N16, and N15 on the outer rotor clockwise, and at the same time pulls S9, S8, S1, and S16 on the outer rotor clockwise. Teeth 8, 6 and 23, 21 of the V-phase winding generate the south pole S, which pushes S5, S4, S13, S12 on the outer rotor clockwise and pulls N5, N4, N13, N12 on the outer rotor clockwise. Teeth 9, 7 and 24, 22 of the V-phase winding generate the north pole N, which pushes N5, N4, N13, N12 on the outer rotor counterclockwise and pulls S6, S5, S14, S13 on the outer rotor clockwise. Teeth 4, 2, 19, and 17 of the U-phase winding generate the south pole (S), which pushes S3, S2, S11, and S10 on the outer rotor clockwise, and simultaneously pulls N3, N2, N11, and N10 on the outer rotor clockwise. Teeth 5, 3, 1, 20, 18, and 16 of the U-phase winding generate the north pole (N), which pushes N3, N2, N1, N11, N10, and N9 on the outer rotor clockwise, and simultaneously pulls S4, S3, S2, S12, S11, and S10 on the outer rotor clockwise. Together, these generate 26 push and 26 pull forces clockwise, causing the outer rotor to rotate clockwise.

[0044] In drive state 5, such as Figure 15 As shown, the output states of the three Hall sensors are HA=H, HB=L and HC=L; Figure 18 In the configuration SH4=L, SH3=L, SH5=L, SL4, SL3 and SL5 output PWM waves to make Figure 19 When circuits T3, T2, T9, T12, T7, and T6 are turned on, current flows into U2, W1, and V1, and flows out through U1, W2, and V2. This produces the following: Figure 15The magnetic poles shown are as follows: teeth 9, 7 and teeth 24, 22, where the V-phase winding is located, generate the south pole S, which pushes S6, S5, S14, S13 on the outer rotor clockwise and simultaneously pulls N6, N5, N14, N13 on the outer rotor clockwise; teeth 10, 8 and teeth 25, 23, where the V-phase winding is located, generate the north pole N, which pushes N6, N5, N14, N13 on the outer rotor counterclockwise and simultaneously pulls S7, S6, S15, S14 on the outer rotor clockwise. Teeth 4, 2 and 19, 17 of the U-phase winding generate the south pole (S), which clockwise pushes S3, S2, S11, S10 on the outer rotor, and simultaneously pulls N3, N2, N11, N10 on the outer rotor clockwise. Teeth 3, 1 and 18, 16 of the U-phase winding generate the north pole (N), which clockwise pushes N2, N1, N10, N9 on the outer rotor, and simultaneously pulls S3, S2, S11, S10 on the outer rotor clockwise. Teeth 30, 28, 26 and teeth 15, 13, 11 of the W-phase winding generate the south pole (S), which pushes S1, S16, S15, S9, S8, S7 on the outer rotor clockwise, while simultaneously pulling N1, N16, N15, N9, N8, N7 on the outer rotor clockwise. Teeth 29, 27 and teeth 14, 12 of the W-phase winding generate the north pole (N), which pushes N16, N15, N8, N7 on the outer rotor clockwise, while simultaneously pulling S1, S16, S9, S8 on the outer rotor clockwise. Together, these generate 26 clockwise thrusts and 26 clockwise pulls, causing the outer rotor to rotate clockwise.

[0045] In drive state 6, such as Figure 16 As shown, the output states of the three Hall sensors are HA=H, HB=H and HC=L; Figure 18 In the configuration of SH3=L, SH5=L, SH1=L, SL3, SL5 and SL1 output PWM waves to make Figure 19 When circuits T9, T12, T7, T6, T1, and T4 are turned on, current flows into W1, V2, and U1, and flows out through W2, V1, and U2. This produces the following effect: Figure 16The magnetic poles shown are as follows: teeth 5 and 3, and teeth 20 and 18, where the U-phase winding is located, generate the south pole (S), which pushes the outer rotor's S4, S3, S12, and S11 clockwise, and simultaneously pulls the outer rotor's N4, N3, N12, and N11 clockwise; teeth 4 and 2, and teeth 19 and 17, where the U-phase winding is located, generate the north pole (N), which pushes the outer rotor's N3, N2, N11, and N10 clockwise, and simultaneously pulls the outer rotor's S4, S3, S12, and S11 clockwise. Teeth 28, 26 and teeth 13, 11 of the W-phase winding generate the south pole S, which pushes S16, S15, S8, S7 on the outer rotor clockwise, and at the same time pulls N16, N15, N8, N7 on the outer rotor clockwise; Teeth 29, 27 and teeth 14, 12 of the W-phase winding generate the north pole N, which pushes N16, N15, N8, N7 on the outer rotor clockwise, and at the same time pulls S1, S16, S9, S8 on the outer rotor clockwise. Teeth 24, 22 and teeth 9, 7 of the V-phase winding generate the South Pole (S), which pushes S14, S13, S6, and S5 of the outer rotor clockwise, and simultaneously pulls N14, N13, N6, and N5 of the outer rotor clockwise. Teeth 25, 23, 21 and teeth 10, 8, and 6 of the V-phase winding generate the North Pole (N), which pushes N14, N13, N12, N6, N5, and N4 of the outer rotor counterclockwise, and simultaneously pulls S15, S14, S13, S7, S6, and S5 of the outer rotor clockwise. Together, these generate 26 clockwise thrusts and 26 clockwise pulls, causing the outer rotor to rotate clockwise.

[0046] After the above six driving states, a 360-degree electrical rotation is completed. The process then repeats, repeating the six driving processes to rotate the motor's outer rotor. As can be seen, each driving state has a total of 52 thrust and pull forces, an increase of 14 compared to the 38 thrust and pull forces in the previous two-phase drive. This represents an increase of 14 / 38 = 36.84%, meaning that torque and power are approximately 36.84% higher than with a traditional motor, demonstrating a significant performance improvement.

[0047] As seen from the above discussion of the two driving methods, only with a deep understanding of the electromagnetic fields generated by the motor's stator and rotor, and meticulous analysis of the magnetic field morphology of each magnetic pole on the rotor and each armature tooth on the stator under each driving state, as well as the analysis of their interaction, good circuit design, and specific experimental verification, can we conduct thorough research on the principles of motors and design drivers. Motor research can be divided into three aspects: first, research on manufacturing processes; second, research on the materials used in the motor; and third, research on the internal electromagnetic fields generated by the motor's stator and rotor and their interaction, as well as research on the driving methods employed. This invention mainly focuses on the third aspect, which is the fundamental and principle-based research, and also the most difficult, but extremely important. Different winding methods, stator slot numbers, rotor pole numbers, and driving methods can all potentially degrade motor performance or even cause it to stop completely. Only through correct analysis, understanding, and experimental verification can motor performance be improved; research on manufacturing processes and materials will not lead to such issues.

[0048] From the above analysis of the six driving states of the two methods of energizing the three-phase windings, it can be seen that the multi-pole external rotor permanent magnet brushless motor of the present invention can realize the independent energizing and driving of the two-phase windings and the three-phase windings when the motor windings are energized and driven.

[0049] The following section explains the switching methods between two-phase drive and three-phase drive:

[0050] exist Figure 18 In the program running in the microcontroller MCU (i.e., IC1), we write instructions (taking the first drive state as an example, its Hall outputs HA=L, HB=L, HC=H, with a hexadecimal value of 0x4).

[0051]

[0052] This enables intelligent switching between single-phase winding energization, two-phase winding energization, and three-phase winding energization during motor operation. M represents the current motor operating power value, which is related to the motor's current speed and operating current. Of course, other methods can also be used to determine the current power and motor operating status. MS is a set power value constant, which is set according to the specific conditions and design requirements of each motor. The other five drive states are set similarly.

[0053] Regarding the driving method, we can also lock the working state selection according to the equipment requirements. For example, PA5 can be used as a state selection switch. When PA5 is low, it is a two-phase drive; when PA5 is high, it is a three-phase drive (of course, another input port can also be selected as the state selection switch). The program is modified as follows:

[0054]

[0055] The SW1 switch can be used to select the locking state of two-phase drive and three-phase drive, just like the D (normal state) and S (sport state) selection of an automatic transmission in a car.

[0056] The motor operates normally under normal load by energizing two-phase windings and under heavy load by energizing all three-phase windings simultaneously. This satisfies both energy-saving requirements and heavy load conditions, thereby further improving the motor's operating efficiency.

[0057] This invention provides a multi-pole external rotor permanent magnet brushless motor, which can meet various working conditions by performing energy-saving operation under light load and normal operation under heavy load when the load changes significantly. It also improves the motor torque, power density and efficiency while saving energy.

[0058] It will be apparent to those skilled in the art that the present invention includes, but is not limited to, the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of the equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims. In particular, it should be noted that magnetic position sensors come in various forms, all of which correctly provide the position signal of the rotor magnetic poles. There are also Hall-less methods that determine the rotor magnet position by detecting the zero-crossing point of the winding current. However, these do not change the driving method of each phase winding of the motor. Similarly, microcontrollers (MCUs) have numerous models that can be used, and they can also be constructed using components such as FPGAs (Field Programmable Gate Arrays). However, these components are not the core of this patent. Generally, for ease of production, the three-phase windings are wound in the same way. Methods that use different winding methods for certain phase windings to achieve the same rotational result simply by changing the direction of the current drive are also included in this invention. Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A multi-pole external rotor permanent magnet brushless motor, comprising an external rotor permanent magnet brushless motor and a driver circuit, characterized in that: The external rotor permanent magnet brushless motor is constructed with an external rotor having a multiple of 16 magnetic poles and an internal stator having a multiple of 15 armature slots. The internal stator of the external rotor permanent magnet brushless motor winding is disc-shaped and has armature teeth and slots on its periphery for winding the coils. It is constructed using laminated magnetic materials such as silicon steel sheets. The internal stator winding uses a concentrated winding method, with the coil wound around a single armature tooth. The magnetic lines of force generated by the winding on the internal stator are perpendicular to the motor shaft. The external rotor consists of a U-shaped disc with permanent magnets mounted radially on its inner side. The magnetic lines of force of the permanent magnets installed inside the U-shaped disc are perpendicular to the motor shaft. The shaft is vertically connected to the outer rotor of the U-shaped disk and located at the center of the outer rotor. The inner stator is fixed inside the U-shaped disk of the outer rotor and is coaxial with the outer rotor. Its driver circuit uses a microcontroller (MCU) for control and an H-bridge power driver. The two ends of each phase winding on the inner stator are respectively connected to their respective H-bridge power drivers on the driver circuit. When the motor windings are energized and driven, it can realize the energization and driving of two-phase windings and the simultaneous energization and driving of all three-phase windings. It can also intelligently switch between the two-phase winding energization and the simultaneous energization of all three-phase windings during motor operation.

2. The multi-pole external rotor permanent magnet brushless motor according to claim 1, characterized in that: The magnetic lines of the permanent magnets installed in the inner radial direction of the U-shaped disc outer rotor are perpendicular to the motor shaft. The magnetic poles of the permanent magnets are arranged with the north and south poles adjacent to each other. The outer rotor can also be composed of a ring of permanent magnets magnetized in the inner radial direction.

3. A multi-pole external rotor permanent magnet brushless motor according to claim 1, characterized in that: The inner stator winding is wound in a concentrated manner around a single armature tooth. There are a total of 5 concentrated coils in the same winding coil on the same phase, and the coils of adjacent armature teeth are wound in opposite directions. The two adjacent windings on the same phase are wound in the same direction, and are placed with a gap of 10 armature teeth in between. The three-phase windings are arranged in a manner where the windings of adjacent phases are placed with a gap of five armature teeth to form the first, second and third phase windings.

4. A multi-pole external rotor permanent magnet brushless motor according to claim 1, 2, or 3, characterized in that: The relationship between the number of permanent magnet poles on the U-shaped disk of the outer rotor and the number of armature teeth on the inner stator is as follows: the number of permanent magnets on the outer rotor is 16 times the coefficient K, and the number of armature teeth on the inner stator is 15 times the coefficient K, where K is a positive integer greater than or equal to 1. When the coefficient K = 1, there are 16 permanent magnets on the outer rotor and 15 armature teeth on the inner stator, with each phase winding having a group of 5 coils wound in a concentrated manner. When the coefficient K = 2, there are 32 permanent magnets on the outer rotor and 30 armature teeth on the inner stator, with each phase winding having a group of 5 coils wound in a concentrated manner. Each phase winding has two groups of five coils wound in a concentrated manner. When the coefficient K = 3, the number of permanent magnets on the outer rotor is 48, the number of armature teeth on the inner stator is 45, and each phase winding has three groups of five coils wound in a concentrated manner. When the coefficient K = 4, the number of permanent magnets on the outer rotor is 64, the number of armature teeth on the inner stator is 60, and each phase winding has four groups of five coils wound in a concentrated manner, and so on. When the coefficient K is greater than 3, the number of permanent magnets on the outer rotor can be reduced or increased by one south pole and one north pole, for a total of two permanent magnets.

5. A multi-pole external rotor permanent magnet brushless motor according to claim 1, characterized in that: Each phase winding power drive device consists of an H-bridge power driver composed of two sets of series-connected composite fully controllable voltage-driven power semiconductor devices (IGBTs) forming the left arm and another two sets of series-connected composite fully controllable voltage-driven power semiconductor devices (IGBTs) forming the right arm. The start and end points of each phase winding are connected to the midpoint of the left and right arms of their respective H-bridge power drivers. The upper and lower control terminals of the left and right arms of each H-bridge power driver are controlled by four different signals. The power drive device can also be a high-power MOSFET or other high-power semiconductor power device.

6. A multi-pole external rotor permanent magnet brushless motor according to claim 1 or claim 5, characterized in that: a driver... When the circuit is energizing the two-phase winding, the driver provides six driving states, each of which energizes two of the three-phase windings.

7. A multi-pole external rotor permanent magnet brushless motor according to claim 1 or claim 5, characterized in that: When the driver circuit is energizing the three-phase windings, the driver provides six driving states, each of which energizes all three phases of the three-phase windings.

8. A multi-pole external rotor permanent magnet brushless motor according to claim 1, characterized in that: The rotational speed of the motor rotor is regulated by a pulse width modulation signal.

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