BLDC brushless motor six-step commutation state machine

Abstract

The invention discloses a BLDC brushless motor six-step commutation state machine, and relates to the technical field of motor design, the BLDC brushless motor six-step commutation state machine comprises a housing, two ends of the housing are fixedly provided with a plurality of bearings, each bearing is provided with a rotor, the rotor comprises a main shaft, the main shaft is fixedly provided with a plurality of driving magnets, the driving magnets are uniformly distributed on the main shaft, and the driving magnets are arranged on the main shaft. The Hall circuit board is provided with a driving magnet, one end of the driving magnet is fixedly provided with a fixed nesting sleeve, the fixed nesting sleeve is fixedly provided with a plurality of small magnets, the small magnets are uniformly distributed on the fixed nesting sleeve, and the small magnets and the driving magnet are installed correspondingly. The brushless motor is used for enhancing Hall induction, positioning of the rotating position of the rotor can be improved, time errors generated when the brushless motor encounters a zero point can be reduced, the rotating speed of the rotor is further increased, and meanwhile the rotor can rotate more smoothly and stably.

Description

Technical Field

[0001] The invention relates to the technical field of motor design, and in particular to a six-step commutation state machine of a BLDC brushless motor. Background Art

[0002] Brushless DC motors (BLDC) control the direction of current electronically, thereby eliminating the sparks and electromagnetic interference generated by the friction between the carbon brushes and the commutator in traditional brushed motors. BLDC motors usually contain a permanent magnet rotor and a stator with a winding. By changing the direction of the current in the winding, magnetic fields in different directions can be generated, thereby driving the rotor to rotate. The six-step commutation state machine is a control strategy based on back-electromotive force zero-crossing detection. It divides one electrical cycle of the motor into six steps, each step corresponding to a specific current direction and rotor position. By switching these six steps in sequence, continuous rotation of the motor can be achieved.

[0003] The Chinese invention patent with announcement number: CN113346800B discloses a rotor position detection method suitable for a brushless DC motor. This invention can realize the detection of the motor rotor position signal by adding 3 Hall sensor position detection signals to the original 3 Hall sensor position detection signals without changing the existing motor.

[0004] In the prior art, when the motor rotates, when the magnetic pole on the motor rotor passes through the zero point, the upper control device needs to change the stator magnetic field, so that the rotor continues to be driven by the stator. At this time, the upper control locates the rotor position through the Hall sensor. If the Hall sensor has a certain error in sensing the rotor position, it will cause a time difference when the upper control collects the rotor status, which will affect the performance of the motor, causing the motor to run unstable and prone to vibration, noise and other problems. It will also reduce the efficiency of the motor, increase energy consumption, increase the wear of motor components, and shorten the service life of the motor. Summary of the invention

[0005] In view of the above technical problems, the present invention proposes the following technical solutions: A six-step commutation state machine of a BLDC brushless motor comprises a shell, a plurality of bearings are fixedly mounted at both ends of the shell, a rotor is arranged on the bearing, the rotor comprises a main shaft, a plurality of driving magnets are fixedly mounted on the main shaft, the driving magnets are evenly distributed on the main shaft, a fixed nest is fixedly mounted on one end of the driving magnet, a plurality of small magnets are fixedly mounted on the fixed nest, the small magnets are made of neodymium iron boron material, the small magnets are evenly distributed on the fixed nest, and the small magnets are mounted corresponding to the driving magnets.

[0006] Furthermore, the magnetic poles of the small magnets are distributed in parallel with the axis direction of the main shaft, and the same magnetic poles of the multiple small magnets are in the same plane.

[0007] Furthermore, the magnetic pole distribution of the driving magnet is perpendicular to the axis direction of the main shaft, and its purpose is to drive the main shaft to rotate.

[0008] Furthermore, an accessory block for counterweight is fixedly mounted on one end of the driving magnet away from the fixed nesting, and the accessory block is made of copper.

[0009] Furthermore, a Hall circuit board for sensing the position of the main shaft is arranged in the housing, the rotor does not contact the Hall circuit board, and the Hall circuit board is arranged on the rotor with one end fixedly nested.

[0010] Furthermore, a plurality of Hall sensors are arranged on the Hall circuit board, and three of the Hall sensors are evenly distributed around the main shaft axis.

[0011] Furthermore, a Hall sensing circuit is provided on the Hall circuit board, and HA, HB, and HC in the Hall sensing circuit correspond to a plurality of Hall sensors on the Hall circuit board.

[0012] Compared with the prior art, the present invention has the following beneficial effects: (1) The present device increases the Hall induction by adding a plurality of axially magnetized small magnets between the rotor and the Hall circuit board, thereby improving the positioning of the rotor rotation position and reducing the time error generated when the brushless motor encounters the zero point. (2) The present device wraps the small magnet by setting a fixed nesting on one side of the driving magnet, and sets the fixed nesting to be made of copper material, thereby reducing the influence on the magnetic field. (3) The present device provides an accessory block on the other side of the driving magnet to counterweight the fixed nesting and the small magnet, thereby preventing the bearing on one side from wearing too fast during the rotation of the rotor, thereby reducing the life of the present device. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0014] Figure 2 It is a schematic diagram of the cross-section structure of the housing, support tube and three-phase stator winding of the present invention.

[0015] Figure 3 It is a schematic diagram of the rotor structure of the present invention.

[0016] Figure 4 This is a schematic diagram of the fixed nested structure of the present invention.

[0017] Figure 5 It is a schematic diagram of the main shaft structure of the present invention.

[0018] Figure 6 It is a schematic diagram of the fixed nested structure after sectioning of the present invention.

[0019] Figure 7 This is a schematic diagram of the driving magnet structure of the present invention.

[0020] Figure 8 This is a schematic diagram of the structure of the Hall circuit board of the present invention.

[0021] Fig. 9 This is the circuit diagram of the Hall effect Hall sensor of the present invention.

[0022] Figure numerals: 101 - housing; 102 - wiring; 103 - bearing; 104 - Hall circuit board; 1041 - Hall sensor; 105 - support cylinder; 106 - three-phase stator winding; 200 - rotor; 201 - main shaft; 202 - fixed nesting; 203 - small magnet; 204 - driving magnet; 205 - accessory block. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0024] like Figure 1 and Figure 2 As shown, a small brushless motor includes a housing 101 and a cable 102, wherein the housing 101 is fixedly connected to the cable 102, a support cylinder 105 is fixedly installed in the housing 101, a three-phase stator winding 106 is arranged in the support cylinder 105, a Hall circuit board 104 for sensing the position of the main shaft is arranged in the housing 101, the Hall circuit board 104 is connected to the cable 102, a plurality of bearings 103 are also fixedly installed at both ends of the housing 101, a rotor 200 is arranged on the bearing 103, the rotor 200 is arranged in the three-phase stator winding 106, the rotor 200 does not contact the three-phase stator winding 106, and the rotor 200 does not contact the Hall circuit board 104.

[0025] like Figures 2 to 7As shown, the rotor 200 includes a main shaft 201, on which a plurality of driving magnets 204 are fixedly mounted, the driving magnets 204 are made of neodymium iron boron material, and are evenly distributed on the main shaft 201. A fixed nesting 202 is fixedly mounted on one end of the driving magnet 204, and an accessory block 205 for counterweight is fixedly mounted on the other end of the driving magnet 204. The accessory block 205 is made of copper, and the fixed nesting 202 is made of copper. A plurality of small magnets 203 are fixedly mounted on the fixed nesting 202, and the small magnets 203 are made of neodymium iron boron material. The small magnets 203 are evenly distributed on the fixed nesting 202. The small magnets 203 are mounted correspondingly to the driving magnets 204, and the outer arc of the small magnets 203 and the driving magnets 204 are the same. The accessory blocks 205 arranged at both ends of 104 have the same weight as the fixed nesting 202 plus the small magnets 203.

[0026] like Figures 3 to 7 As shown, the magnetic pole distribution of the small magnets 203 is parallel to the axial direction of the main shaft 201, and the same magnetic pole direction of the multiple small magnets 203 is on the same plane. For example, if one end of any small magnet 203 away from the driving magnet 204 is an N pole, then the end of this small magnet 203 close to the driving magnet 204 is an S pole, and the ends of all small magnets 203 away from the driving magnet 204 should be the same N pole. The magnetic pole distribution of the driving magnet 204 is perpendicular to the axial direction of the main shaft 201, and its purpose is to drive the main shaft 201 to rotate.

[0027] like Figure 2 , Figure 8 , Fig. 9 As shown, a plurality of Hall sensors 1041 are arranged on the Hall circuit board 104, and three Hall sensors 1041 are evenly distributed around the axis of the main shaft 201, and the angle between the plurality of Hall sensors 1041 is one hundred and twenty degrees. A Hall sensing circuit is arranged on the Hall circuit board 104, and HA, HB, and HC in the Hall sensing circuit correspond to the plurality of Hall sensors 1041 on the Hall circuit board 104, respectively.

[0028] Working principle of the device: When the device is in use, before the upper control is ready to let the rotor start to rotate, the Hall sensor 1041 on the Hall circuit board 104 detects the N or S magnetic pole signal on the small magnet 203, and the Hall sensor 1041 will receive the magnetic type emitted by the small magnet 203 at this time, and the magnetic signal received by the Hall sensor 1041 will be converted into Fig. 9HA, HB, and HC correspond to the electrical signals of the Hall sensor 1041, and the electrical signal generated by any one of HA, HB, and HC will be transmitted to the upper control, thereby informing the upper control of the current angle of the rotor 200. At this time, the upper control will react through this electrical signal. After receiving the signal, the upper control changes the magnetic poles of the three-phase stator winding 106 through the upper control control, pulling the rotor 200 to rotate.

[0029] During the rotation of the rotor 200, the small magnet 203 will also rotate with it. In this way, when the rotor 200 rotates, the small magnet 203 will continuously pass through multiple Hall sensors 1041, and the Hall sensor 1041 will receive the magnetic pattern emitted by the small magnet 203 at this time. The Hall sensor 1041 will receive the magnetic pattern and convert it into Fig. 9 HA, HB, and HC correspond to the electrical signals of the Hall sensor 1041, and then this electrical signal will be transmitted to the upper control to inform the upper control of the current rotation angle of the rotor 200. When the rotor 200 rotates to the zero point, the upper control needs to change the current flow direction in the three-phase stator winding 106, so as to change the magnetic field on the three-phase stator winding 106 to form a thrust, and then let the rotor 200 continue to rotate. In this way, the current of the three-phase winding is changed cyclically, and the rotor will rotate at a high speed. The device adds a plurality of axially magnetized small magnets 203 at the position between the rotor 200 and the Hall circuit board 104 to enhance the Hall induction, thereby further improving the positioning of the rotation position of the rotor 200. The time error generated by the unimproved brushless motor when encountering the zero point is 30%-40%, and after adding the small magnet 203, the time difference range of its Hall induction is reduced to 15%-20%, which can not only increase the rotation speed of the rotor 200, but also make the rotation of the rotor 200 smoother and more stable.

[0030] The above description is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention.

Claims

1. A six-step commutation state machine of a BLDC brushless motor, comprising a housing (101), wherein two ends of the housing (101) are further fixedly mounted with a plurality of bearings (103), characterized in that: A rotor (200) is arranged on the bearing (103), and the rotor (200) comprises a main shaft (201), a plurality of driving magnets (204) are fixedly mounted on the main shaft (201), and the driving magnets (204) are evenly distributed on the main shaft (201), a fixed nest (202) is fixedly mounted on one end of the driving magnet (204), a plurality of small magnets (203) are fixedly mounted on the fixed nest (202), the small magnets (203) are made of neodymium iron boron material, the small magnets (203) are evenly distributed on the fixed nest (202), and the small magnets (203) and the driving magnets (204) are mounted correspondingly.

2. According to claim 1, a six-step commutation state machine of a BLDC brushless motor is characterized in that: The magnetic poles of the small magnets (203) are distributed in parallel with the axial direction of the main shaft (201), and the same magnetic poles of the plurality of small magnets (203) are in the same plane.

3. According to claim 1, a six-step commutation state machine of a BLDC brushless motor is characterized in that: The magnetic pole distribution of the driving magnet (204) is perpendicular to the axial direction of the main shaft (201), and its purpose is to drive the main shaft (201) to rotate.

4. According to claim 1, a six-step commutation state machine of a BLDC brushless motor is characterized in that: An accessory block (205) for counterweight is fixedly mounted on one end of the driving magnet (204) away from the fixed nest (202), and the accessory block (205) is made of copper.

5. The six-step commutation state machine of a BLDC brushless motor according to claim 1, characterized in that: A Hall circuit board (104) for sensing the position of the main shaft is arranged in the housing (101); the rotor (200) does not contact the Hall circuit board (104); and the Hall circuit board (104) is arranged on one end of the rotor (200) where a fixed nest (202) is provided.

6. The six-step commutation state machine of a BLDC brushless motor according to claim 5, characterized in that: A plurality of Hall sensors (1041) are arranged on the Hall circuit board (104), and three of the Hall sensors (1041) are evenly distributed around the axis of the main shaft (201).

7. The six-step commutation state machine of a BLDC brushless motor according to claim 5, characterized in that: The Hall circuit board (104) is provided with a Hall sensing circuit, and HA, HB and HC in the Hall sensing circuit correspond to a plurality of Hall sensors (1041) on the Hall circuit board (104).

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