A self-driven permanent magnet brushless motor and device

Abstract

The present invention discloses a self-driven permanent magnet brushless motor and a device. The motor includes a stator, a rotor, an induction switch, and a signal component. The number of induction switches is the same as the number of phases of the stator; the rotor is fixedly connected to the signal component. When the signal component rotates with the rotor and passes through each induction switch, induction regions are evenly distributed on the signal component; the regional included angle of each induction region satisfies a certain angular relationship; the included angle X between the axis of symmetry line of the induction region and the magnetic pole demarcation line of the rotor, and the included angle Y between the axis of symmetry line of the stator coil and the axis of symmetry line of the induction switch, and the angles of X and Y satisfy a certain corresponding relationship. The structure of the present invention enables more accurate control of the brushless motor, more uniform rotational torque, and higher efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of brushless motors, and particularly to a self-driven permanent magnet brushless motor and a device. Background Art

[0002] The permanent magnet brushless motor mainly consists of two parts: a motor body and a drive circuit, and is a typical mechatronic product. This type of motor replaces the brush and commutator structure of the traditional brushed motor through a drive circuit, making the motor have a longer lifespan, lower noise, and higher efficiency. However, the drive circuit of the existing brushless motor consists of complex sensing circuits and control circuits, and its cost is comparable to that of the motor body, or even slightly higher than that of the motor body. Therefore, compared with the brushed motor, the cost of the brushless motor is relatively high, which limits its wide application in products.

[0003] In response to this problem, there is a technical solution in the prior art to drive the brushless motor to operate through an induction switch. The induction switch controls the on-off of the corresponding stator coil windings to drive the rotor to rotate, thereby realizing the drive of the brushless motor. This technology eliminates the complex sensing and drive control circuits of the traditional brushless motor, greatly reducing the cost of the motor. However, due to defects in the design of the induction switch and unclear parameters in the above solution, it is easy to cause problems such as the motor being unable to start or accurately control the starting direction, large torque fluctuations, high noise, serious heating, and low working efficiency of the motor, and it cannot meet the actual application requirements. Summary of the Invention

[0004] In view of the above problems, the present invention proposes a self-driven permanent magnet brushless motor and a device, which can achieve accurate motor control, uniform torque, stable operation, and high working efficiency.

[0005] A self-driven permanent magnet brushless motor provided by the present invention includes a stator, a rotor, an induction switch, and a signal component. The number of the induction switches is the same as the number of phases of the stator; the rotor is fixedly connected to the signal component, and when the signal component rotates with the rotor and passes through each induction switch, the signal component is provided with uniformly distributed induction regions; when the stator phases are connected in parallel, the regional angle α of each induction region satisfies: stator winding angle / n < α < rotor magnetic pole angle, where the stator winding angle is the angle occupied by a single winding in the circumference, the rotor magnetic pole angle is the angle occupied by a single magnetic pole in the circumference, and n is the ratio of the number of rotor pole pairs to the number of stator pole pairs, n = 1, 2, 3,...; the included angle between the axis of symmetry of the induction region and the magnetic pole demarcation line of the rotor is X, and the included angle between the axis of symmetry of the stator coil and the axis of symmetry of the adjacent induction switch corresponding to its connection is Y, and X = Y. When the stator phases are connected in a star connection, the regional angle α of each induction region satisfies: stator winding angle / 2n < α < stator winding angle / n; the included angle between the axis of symmetry of the induction region and the magnetic pole demarcation line of the rotor is X, and the included angle between the axis of symmetry of the stator coil and the axis of symmetry of the adjacent induction switch corresponding to its connection is Y, and X = Y ± stator winding angle / 4n, where n is the ratio of the number of rotor pole pairs to the number of stator pole pairs, n = 1, 2, 3,...

[0006] Further, each induction switch has one induction point or two induction points. When one induction point is used, the number of the induction regions is the same as the number of rotor pole pairs. When two induction points are used, the induction points are distributed along the diameter direction of the circle formed by the endpoints of the signal component, and the number of the induction regions is twice the number of rotor pole pairs. This structure can ensure that at least two groups of stator coils are energized simultaneously at any time, driving the rotor to rotate, making the motor output a greater torque and significantly improving the working efficiency.

[0007] Further, the induction switch is an optoelectronic switch, the signal component is a light-shielding disc, and the induction region on the light-shielding disc is a light-passing groove.

[0008] Even further, the optoelectronic switch is of a transmissive structure or a reflective structure. In the case of the transmissive structure, when the light-passing groove passes through the optoelectronic switch, the optoelectronic switch is turned on; in the case of the reflective structure, when the light-passing groove passes through the optoelectronic switch, the optoelectronic switch is turned off.

[0009] Further, the induction switch is a Hall switch, and the signal component is a magnetic disc or a magnetic pole.

[0010] Further, the induction switch is a capacitive switch, and the signal component is a measured electrode plate.

[0011] The present invention also provides a device, including the self-driven permanent magnet brushless motor described in any of the above technical solutions.

[0012] Further, the device further includes a control unit. The induction switch in the motor is connected to the control unit through a wire, and can realize real-time feedback on the rotation speed of the motor so as to perform dynamic control.

[0013] The induction areas on the signal part of the present invention are evenly distributed, ensuring uniform and continuous stable rotation torque of the motor; the included angles of the induction areas meet certain conditions, so that at least one induction switch is in the on state at any time, avoiding the motor having a dead zone and being unable to be driven, and making the torque directions given to the rotor the same and the magnitudes equal when each coil is connected during the rotation of the rotor, so that the rotation torque of the motor is greater, more stable and more efficient; making the two included angles X and Y satisfy a certain relationship can enable the rotor to be controlled to rotate in a determined direction regardless of its angle, and control it to work within the optimal efficiency range, thus making the control of the motor more accurate and reliable and the performance better. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0015] Figure 1 It is a structural decomposition diagram of an embodiment of the self-driven permanent magnet brushless motor of the present invention;

[0016] Figure 2 It is Figure 1 A schematic diagram of the structure of the permanent magnet rotor in the embodiment;

[0017] Figure 3 It is a schematic diagram of the included angle of the rotor magnetic poles of the self-driven permanent magnet brushless motor;

[0018] Figure 4 It is a schematic diagram of the included angle of the stator windings of the self-driven permanent magnet brushless motor;

[0019] Figure 5 It is a schematic diagram of the X included angle of the self-driven permanent magnet brushless motor;

[0020] Figure 6 It is a schematic diagram of the Y included angle of the self-driven permanent magnet brushless motor;

[0021] Figure 7 It is a schematic diagram of the structure of the self-driven permanent magnet brushless motor with two induction points in another embodiment;

[0022] Figure 8 Schematic diagram of a transmissive photoelectric switch in an embodiment of the self-driven permanent magnet brushless motor of the present invention;

[0023] Figure 9 Schematic diagram of a reflective photoelectric switch in an embodiment of the self-driven permanent magnet brushless motor of the present invention;

[0024] Figure 10 Schematic circuit diagram of a unidirectional rotating self-driven permanent magnet brushless motor;

[0025] Figure 11 Schematic circuit diagram of a bidirectional rotating self-driven permanent magnet brushless motor;

[0026] Figure 12 is Figure 7 Schematic circuit diagram of the embodiment;

[0027] Figure 13 is Figure 7 Schematic circuit diagram of the star connection of the three-phase stator in the embodiment;

[0028] Reference numerals:

[0029] 1 - housing, 2 - rotor, 3 - stator, 4 - signal member, 41 - induction area, 5 - induction switch, 51 - induction point. Detailed implementation manners

[0030] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to 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 used to limit the present invention.

[0031] As Figure 1 shown, the permanent magnet brushless motor includes a housing 1, a stator 3, a rotor 2, an induction switch 5 and a signal member 4. The rotor 2 includes one pair or multiple pairs of magnetic poles, and the stator 3 is a coil winding uniformly distributed around the rotor 2.

[0032] As Figure 2 and Figure 6 shown, the number of induction switches 5 is the same as the number of phases of the stator 3. The rotor 2 is fixedly connected to the signal member 4. When the signal member 4 rotates with the rotor 2 and passes through each induction switch 5, the signal member 4 is provided with uniformly distributed induction areas 41.

[0033] When the stators 3 of each phase are connected in parallel and the induction switch 5 has only one induction point, the number of induction areas 41 is the same as the number of pole pairs of the rotor 2. As Figure 6As shown, there is an induction point 51 on the induction switch 5. When the induction area 41 rotates to the position of the induction point 51, the induction switch 5 is turned on, and the corresponding coil winding stator 3 is powered on, thereby generating a magnetic force to push the rotor 2 to rotate. The rotor 2 drives the signal part 4 to rotate together. When the induction area 41 rotates out of alignment with the induction point 51, the induction switch 5 is turned off, and the corresponding coil winding stator 3 loses power. In this case, to make the rotor rotate continuously, the area angle α of each induction area 41 must satisfy: stator winding angle / n < α < rotor magnetic pole angle, where n is the ratio of the number of rotor poles to the number of stator poles, and n = 1, 2, 3,.... The stator winding angle is as Figure 4 shown, and the rotor magnetic pole angle is as Figure 3 shown. When the area angle α is within the above range, on the one hand, at least one induction switch 5 is in the on state at any time, avoiding the motor having a dead zone and being unable to start, and at the same time ensuring that the stator of each phase coil winding can achieve stable continuous relay. On the other hand, it can make the stator disconnect the power supply before the rotor rotates to the maximum acting force, or power on after the rotor rotates to the maximum acting force, so as to avoid generating resistance to hinder rotation.

[0034] The included angle between the axis of symmetry of the induction area 41 and the magnetic pole dividing line of the rotor 2 is X, and the included angle between the axis of symmetry of the stator 3 coil and the axis of symmetry of the induction switch 5 is Y. As Figure 5 and Figure 6 shown, the relationship between these two included angles is: X = Y. Such a structure makes the torque direction given to the rotor 2 the same and the magnitude equal when each coil is turned on during the rotation of the rotor 2, so that the rotation torque of the motor is greater, more stable, and the efficiency is higher.

[0035] When there are two induction points on the induction switch 5, as Figure 7 shown, the two induction points 51 are distributed along the diameter of the signal part 4, which is the case when the signal part 4 is a disc; when the signal part 4 is of other shapes, the induction points 51 are distributed along the diameter of the circle formed by the endpoints of the signal part 4. Correspondingly, the number of induction areas 41 on the signal part 4 will also increase, which is twice the number of rotor poles. Every two adjacent induction areas 41 are staggered, so that they act on the two induction points 51 on each induction switch 5 successively during rotation. This structure can ensure that at least two groups of stator coils are powered on simultaneously at any time to push the rotor to rotate, making the output torque of the motor greater and the working efficiency greatly improved.

[0036] In addition, when using as Figure 7When the induction switch with two induction points as shown is used, the connection mode between the stator windings 3 of each phase can also adopt the star connection mode. When the stator 3 adopts the star connection, the included angle α of each induction area 41 satisfies: stator winding included angle / 2n < α < stator winding included angle / n. The included angle X between the axis of symmetry line of the induction area 41 and the magnetic pole demarcation line of the rotor 2, and the included angle Y between the axis of symmetry line of the stator 3 coil and the axis of symmetry line of the induction switch 5 satisfy X = Y ± stator winding included angle / 4n, where n is the ratio of the number of rotor poles to the number of stator poles, and n = 1, 2, 3,.... Similarly, by limiting the range of α and the included angle relationship between X and Y, on the one hand, it ensures that at least one signal point of the induction switch 5 is in the conduction state at any time, avoiding the motor having a dead zone and being unable to be driven. On the other hand, it enables the stator to disconnect the power supply before the rotor rotates to the maximum acting force or reconnect the power supply after rotating to the maximum acting force, so as to avoid generating resistance to hinder the rotation.

[0037] As a form of implementing the above technical solution, the induction switch 5 is a photoelectric switch, and the corresponding signal member 4 is a light shielding disc, on which light passing grooves are evenly distributed.

[0038] The photoelectric switch is divided into two types: transmissive type and reflective type. When the transmissive type photoelectric switch is used, the induction area 41 is the light passing groove at this time. The transmitting end and the receiving end of the photoelectric switch are located on both sides of the light shielding disc. When the light passing groove passes through the photoelectric switch, the switch is turned on, as Figure 8 shown; when the reflective type photoelectric switch is used, it only needs to be installed on one side of the light shielding disc, which is more convenient for motor assembly, has a more compact structure and a smaller volume. At this time, the induction area 41 is the part of the light shielding disc outside the light passing groove. When the light passing groove passes through the photoelectric switch, the switch is turned off, as Figure 9 shown.

[0039] If the structure as Figure 7 shown is adopted, the two induction points of the induction switch 5 correspond to the inner and outer light passing grooves of the light shielding disc. For the stator connected in parallel, the induction point 51 near the outer edge of the light shielding disc controls the forward (or reverse) power supply of the stator coil, and the induction point 51 near the inner edge of the light shielding disc controls the reverse (or forward) power supply of the stator coil. For the stator connected in star connection, the induction point 51 near the outer edge of the light shielding disc controls the current to flow into or out of two of the three-phase windings, and the induction point 51 near the inner edge of the light shielding disc controls the current to flow reversely into or out of these two phases. Six signals are generated by three induction switches, and the six signals are connected to the drive circuit according to a certain drive sequence to realize the continuous rotation of the motor.

[0040] As another form of implementing the above technical solution, the induction switch 5 is a Hall switch, and the signal component 4 is a disk or a magnetic pole. When the Hall switch has two induction points 51, the induction points 51 are respectively two different unipolar Hall switches. One type of polarity switch only acts on the N-pole magnetic field, and the other only acts on the S-pole magnetic field.

[0041] As yet another form of implementing the above technical solution, the induction switch 5 is a capacitive switch, and the signal component 4 is the measured electrode plate. When the capacitive switch has two induction points 51, that is, there are two induction electrodes. At this time, the signal component 4 is two measured electrode plates, or there are two sets of uniformly distributed induction regions on one measured electrode plate.

[0042] Only several combinations of induction switches and signal components are listed above. In fact, there may be other contact or non-contact switches that can be applied to the technical solution of this embodiment, and they are all within the scope of the inventive concept of the present invention.

[0043] Figures 10 to 13 is the circuit schematic diagram of a permanent magnet brushless motor, Figure 10 is a single-direction rotation motor with the stator in parallel, Figure 11 is a forward and reverse rotation motor with the stator in parallel. Figure 10 On the left side of the dashed line in is the optoelectronic switch circuit. Its transmitting end is a light-emitting diode, and the receiving end is a photosensitive triode. The signal component 4 is in the middle. When the optical signal at the transmitting end can be received by the receiving end, the photosensitive triode conducts, and the generated electrical signal enters the power module on the right side of the dashed line. The power module includes a field effect transistor. Its gate is connected to the signal output end of the optoelectronic switch, the drain is connected to the positive power supply VDD, the source is connected to the motor stator coil, and then connected to the negative power supply. The optoelectronic switch module and the power module are connected to the common ground. In this way, the optoelectronic switch and the power module form a complete branch. Multiple optoelectronic switches are connected to the multi-phase stator to form multiple branches, all of which are connected in parallel to the power supply VDD. When a certain optoelectronic switch conducts, the stator coil in this branch is energized to generate a magnetic force, driving the rotor 2 to move. The rotor 2 drives the signal component 4 to rotate. Before the rotor 2 rotates to the point where it is about to reach the maximum force point, the signal component 4 triggers the next optoelectronic switch to conduct, and the next-phase stator coil is energized, generating a magnetic force to continue driving the rotor 2 to move. At the same time, the previous optoelectronic switch disconnects, and the newly energized stator coil continues to drive the rotor 2 to rotate. In this way, the continuous rotational movement of the rotor 2 is realized.

[0044] Figure 10 The motor connected in the way shown can achieve low circuit cost, but can only rotate in one direction. Figure 11Among them, for each group of power modules on the right side of the dotted line, the gates of two field effect transistors are connected in parallel and then connected to the signal line of the optoelectronic switch; after the sources are each connected to a diode and then connected in parallel in the forward and reverse directions, they are then connected to the stator coil to form a branch. Multiple such branches are connected in parallel to the power supply circuit. The motor connected in this way can achieve forward and reverse rotation of the motor by reversing the positive and negative poles of the power supply.

[0045] Figure 12 is Figure 7 It is the circuit schematic diagram of the embodiment. On the left is an induction switch circuit with two induction points, in the middle is a forward and reverse rotation switching module, and on the right is a drive circuit with four field effect transistors connected in a bridge. When the motor does not need to switch forward and reverse, the induction point 51 of the induction switch on the left can be directly connected to the corresponding signal point of the bridge drive circuit on the right. When the motor needs to switch forward and reverse, a forward and reverse rotation drive module needs to be added. The function of the forward and reverse rotation drive module is to switch the signal points of the induction switch. For example, when rotating forward, the signal of a1 is output to a1 ', and the signal of a2 is output to a2 '. When rotating in reverse, a1 is output to a2 ', and a2 is output to a1’. The function of the forward and reverse rotation switching module can be realized by a mechanical switch or by a circuit.

[0046] Figure 13 is Figure 7 It is the circuit schematic diagram of the star connection form of the stator in the embodiment. On the left, six field effect transistors form a three-phase inverter circuit, and on the right, the three-phase windings are star-connected. Three induction switches generate six signals, and each signal is connected to the control terminals of the six field effect transistors in pairs. For example, when the motor rotates clockwise, the order of triggering of the induction switch signals is a1 - c2 - b1 - a2 - c1 - b2. To drive the brushless motor to rotate clockwise, the order of winding energization is AB--AC--BC--BA--CA—CB. Therefore, the a1 signal is connected to the inverters sw1 and sw4, the c2 signal is connected to sw1 and sw2, and so on.

[0047] The permanent magnet brushless motor described in this embodiment can be an inner rotor motor or an outer rotor motor.

[0048] This embodiment also provides a device, which can be a household appliance or an industrial electrical device, including the permanent magnet brushless motor described in any of the above technical solutions. The device with automatic control also includes a control unit. The induction switch 5 in the motor is connected to the control unit, and the signal frequency of the induction switch 5 is fed back to the control unit, so that the control unit can know the actual running speed of the motor. According to actual needs, the control unit can automatically adjust the size of VDD to achieve closed-loop control of the motor.

[0049] The technical means disclosed in the solution of the present invention are not limited to the technical means disclosed in the above embodiments, but also include technical solutions composed of any combination of the above technical features.

Claims

1. A self-driven permanent magnet brushless motor, comprising a stator, a rotor, an induction switch, and a signal component. The number of the induction switches is the same as the number of phases of the stator; the rotor is fixedly connected to the signal component, and when the signal component rotates with the rotor, it passes through each induction switch. Characterized in that: The signal component is provided with uniformly distributed induction regions; when the stator phases are connected in parallel, the regional angle α of each induction region satisfies: stator winding angle / n < α < rotor pole angle, where the stator winding angle is the angle occupied by a single winding in the circumference, the rotor pole angle is the angle occupied by a single pole in the circumference, and n is the ratio of the number of rotor pole pairs to the number of stator pole pairs, n = 1, 2, 3,...; the included angle between the axis of symmetry of the induction region and the magnetic pole demarcation line of the rotor is X, and the included angle between the axis of symmetry of the stator coil and the axis of symmetry of the adjacent induction switch connected thereto is Y, X = Y; when the stator phases are connected in a star connection, the regional angle α of each induction region satisfies: stator winding angle / 2n < α < stator winding angle / n; the included angle between the axis of symmetry of the induction region and the magnetic pole demarcation line of the rotor is X, and the included angle between the axis of symmetry of the stator coil and the axis of symmetry of the adjacent induction switch connected thereto is Y, X = Y ± stator winding angle / 4n, where n is the ratio of the number of rotor pole pairs to the number of stator pole pairs, n = 1, 2, 3,...

2. The self-driven permanent magnet brushless motor according to claim 1, Characterized in that: Each induction switch has one induction point or two induction points. When one induction point is adopted, the number of the induction regions is the same as the number of rotor pole pairs; when two induction points are adopted, the induction points are distributed along the diameter direction of the circle formed by the endpoints of the signal component, and the number of the induction regions is twice the number of rotor pole pairs.

3. The self-driven permanent magnet brushless motor according to claim 1, Characterized in that: The induction switch is an optoelectronic switch, the signal component is a light-shielding disc, and the induction region on the light-shielding disc is a light-passing groove.

4. The self-driven permanent magnet brushless motor according to claim 3, Characterized in that: The optoelectronic switch is of a transmissive structure or a reflective structure. In the transmissive structure, when the light-passing groove passes through the optoelectronic switch, the optoelectronic switch is turned on; In the reflective structure, when the light-passing groove passes through the optoelectronic switch, the optoelectronic switch is turned off.

5. The self-driven permanent magnet brushless motor according to claim 1, Characterized in that: The induction switch is a Hall switch, and the signal component is a magnetic disc or a magnetic pole.

6. The self-driven permanent magnet brushless motor according to claim 1, Characterized in that: The induction switch is a capacitance switch, and the signal component is a measured electrode plate.

7. A device, Characterized in that: It includes the self-driven permanent magnet brushless motor according to any one of claims 1 to 6.

8. The device according to claim 7, further comprising a control unit, and the induction switch in the motor is connected to the control unit through a wire.

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