Bidirectional series excitation brush motor, control circuit and control method

Abstract

The invention relates to a bidirectional series excitation brush motor, a control circuit and a control method. The bidirectional series excitation brush motor comprises a rotor winding; the electric brush group comprises a first electric brush and a second electric brush; the stator iron core group comprises a first stator iron core and a second stator iron core which are symmetrically arranged on the outer side of the rotor winding; the two groups of forward stator windings are respectively a first forward stator winding wound on the first stator iron core and a second forward stator winding wound on the second stator iron core, and the first forward stator winding is connected with the second forward stator winding; the two groups of reverse stator windings are respectively a first reverse stator winding wound on the first stator iron core and a second reverse stator winding wound on the second stator iron core, and the first reverse stator winding is connected with the second reverse stator winding; and the electrode group comprises a common electrode, a forward electrode and a reverse electrode. According to the invention, while forward and reverse speed regulation of the brush motor is satisfied, the complexity of a motor control circuit and the complexity of a control algorithm can be reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of motors, and in particular to a bidirectional series-excited brushed motor, a control circuit and a control method. Background Art

[0002] In the current market, brushed motors are popular because of their intuitive structure, low manufacturing cost and simple control. However, when traditional brushed motors achieve clockwise and counterclockwise rotation, they usually need to build an H-bridge drive circuit containing four MOS tubes. This design not only requires the upper bridge arm to use PMOS or NMOS equipped with charge pump pre-drive, but also virtually increases the construction cost of the controller circuit and the complexity of the control logic.

[0003] Therefore, it is necessary to develop a new bidirectional series-excited brushless motor, a control circuit and a control method. Summary of the invention

[0004] The object of the present invention is to provide a bidirectional series-excited brushed motor, a control circuit and a control method, which can reduce the complexity of the motor control circuit and the complexity of the control algorithm while meeting the forward and reverse speed regulation of the brushed motor.

[0005] In a first aspect, a bidirectional series-excited brushless motor according to the present invention comprises: Rotor winding; A brush assembly, which includes at least a first brush and a second brush, which are used for introducing and exporting current respectively, and realize current transmission through contact points with the rotor winding; A stator core assembly, comprising a first stator core and a second stator core symmetrically arranged outside the rotor winding, providing support for the stator winding and generating a magnetic field; Two sets of forward stator windings, namely a first forward stator winding wound on a first stator core and a second forward stator winding wound on a second stator core, and the first forward stator winding and the second forward stator winding are connected to generate a forward magnetic field when powered on to drive the rotor winding to rotate in a forward direction; Two sets of reverse stator windings, namely a first reverse stator winding wound on the first stator core and a second reverse stator winding wound on the second stator core, and the first reverse stator winding and the second reverse stator winding are connected to generate a reverse magnetic field when power is supplied, so as to drive the rotor winding to rotate in the reverse direction; An electrode group includes a common electrode, a forward electrode and a reverse electrode, wherein the common electrode is connected to a first brush, the forward electrode is connected to a second forward stator winding, the reverse electrode is connected to a second reverse stator winding, and the first forward stator winding and the first reverse stator winding are respectively connected to the second brush for controlling the flow of current in different directions.

[0006] Optionally, when controlling the bidirectional series-excited brushed motor to rotate forward, by applying voltage to the common electrode and the positive electrode, the current flows through the common electrode, the first brush, the rotor winding, the second brush, the first positive stator winding, the second positive stator winding in sequence, and finally flows out from the positive electrode, thereby generating a positive magnetic field on the stator core group and driving the rotor winding to rotate forward.

[0007] Optionally, when controlling the bidirectional series-excited brushed motor to rotate in reverse, by applying voltage to the common electrode and the reverse electrode, the current flows through the common electrode, the first brush, the rotor winding, the second brush, the first reverse stator winding, the second reverse stator winding in sequence, and finally flows out from the reverse electrode, thereby generating a reverse magnetic field on the stator core group and driving the rotor winding to rotate in reverse.

[0008] In a second aspect, a control circuit of a bidirectional series-excited brushless motor according to the present invention is used to control the bidirectional series-excited brushless motor according to the present invention, and the method includes: A driving module, comprising two switch elements, wherein a first end of one switch element is connected to a positive electrode of a bidirectional series-excited brushed motor, and a first end of another switch element is connected to a reverse electrode of the bidirectional series-excited brushed motor; The control module is connected to the control ends of the two switch elements respectively, and is used to control the conduction and disconnection of the two switch elements, thereby controlling the operation, stop and steering of the bidirectional series-excited brushed motor.

[0009] Optionally, both switch elements are NMOS tubes, wherein the drain of one NMOS tube is connected to the positive electrode of the bidirectional series-excited brushed motor, the drain of the other NMOS tube is connected to the reverse electrode of the bidirectional series-excited brushed motor, the sources of the two NMOS tubes are grounded, and the gates of the two NMOS tubes are connected to the control module. Compared with PMOS tubes, relays and triodes, the use of NMOS tubes has better performance and lower cost.

[0010] In a third aspect, a control method of a bidirectional series-excited brushed motor according to the present invention adopts the bidirectional series-excited brushed motor according to the present invention, and adopts the control circuit of the bidirectional series-excited brushed motor according to the present invention, and the method comprises the following steps: When the bidirectional series-excited brushed motor is controlled to rotate forward, the switch connected to the forward electrode of the bidirectional series-excited brushed motor is controlled to be turned on through the control module, that is, a voltage is applied to the common electrode and the forward electrode of the bidirectional series-excited brushed motor, so that the current flows through the common electrode, the first brush, the rotor winding, the second brush, the first forward stator winding, the second forward stator winding in sequence, and finally flows out from the forward electrode, thereby generating a forward magnetic field on the stator core group. At this time, the first stator core generates a forward magnetic field of the N pole and the second stator core generates a forward magnetic field of the S pole, driving the rotor winding to rotate forward; When the bidirectional series-excited brushed motor is controlled to rotate in reverse, the control module controls the switch connected to the reverse electrode of the bidirectional series-excited brushed motor to be turned on, and voltage is applied to the common electrode and the reverse electrode so that the current flows through the common electrode, the first brush, the rotor winding, the second brush, the first reverse stator winding, the second reverse stator winding in sequence, and finally flows out from the reverse electrode. At this time, the first stator core generates an S-pole and the second stator core generates an N-pole reverse magnetic field, thereby generating a reverse magnetic field on the stator core group, driving the rotor winding to rotate in reverse.

[0011] Beneficial effects of the present invention: (1) The present invention innovatively develops a brushed motor design with a simple structure, stable performance, and easy production. This design only requires two switches to easily drive the motor to rotate forward and reverse. This breakthrough greatly simplifies the circuit structure and reduces the difficulty of implementing the control strategy, thereby effectively reducing the overall product production cost and providing users with a more convenient application experience. This brushed motor not only retains the cost advantage and control convenience of traditional motors, but also achieves significant improvements in circuit design and control efficiency.

[0012] (2) The drive module of the present invention is simpler than the traditional H-bridge drive module composed of four MOS tubes. Only two switch components (such as NMOS tubes) are needed to realize the forward and reverse control of the motor, which significantly reduces the complexity and production cost of the control circuit and improves the simplicity of the control algorithm. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a structural schematic diagram of the bidirectional series-excited brushed motor described in the embodiment of the present application; Figure 2 Schematic diagram of the forward rotation of the bidirectional series-excited brushed motor described in the embodiment of the present application; Figure 3 Schematic diagram of reverse rotation of the bidirectional series-excited brushed motor described in the embodiment of the present application; Figure 4 It is a principle block diagram of the control circuit of the bidirectional series-excited brushless motor described in the embodiment of the present application; Figure 5 is a circuit diagram of a drive module of a control circuit of a bidirectional series-excited brushed motor described in an embodiment of the present application; Figure 6 is a forward control circuit diagram of a bidirectional series-excited brushed motor described in an embodiment of the present application; Figure 7 It is a reverse control circuit diagram of the bidirectional series-excited brushed motor described in the embodiment of the present application; Figure 8 It is the circuit diagram of the existing H-bridge driver module; In the figure: 1. first brush, 2. rotor winding, 3. first stator core, 4. first forward stator winding, 5. first reverse stator winding, 6. second brush, 7. forward electrode, 8. reverse electrode, 9. common electrode, 10. second reverse stator winding, 11. second forward stator winding, 12. second stator core, 13. drive module, 14. control module, 15. bidirectional series-excited brushed motor, 16. switch element. DETAILED DESCRIPTION

[0014] The following will describe the embodiments of the present invention with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are only for illustrating the present invention, not for limiting the scope of protection of the present invention.

[0015] like Figure 1As shown, in an embodiment of the present application, a bidirectional series-excited brushed motor includes a rotor winding 2, a brush set, a stator core set, two groups of forward stator windings, two groups of reverse stator windings and an electrode set. The rotor winding 2 is placed inside the motor for rotating under force in a magnetic field. The brush set includes at least a first brush 1 and a second brush 6, which are used for the introduction and extraction of current, respectively, and realize the transmission of current through the contact point with the rotor winding 2. The stator core set includes a first stator core 3 and a second stator core 12 symmetrically arranged on the outside of the rotor winding 2, providing support for the stator winding and generating a magnetic field. The two groups of forward stator windings are respectively a first forward stator winding 4 wound on the first stator core 3 and a second forward stator winding 11 wound on the second stator core 12, and the first forward stator winding 4 and the second forward stator winding 11 are connected to generate a forward magnetic field when power is turned on, driving the rotor winding 2 to rotate in the forward direction. The two groups of reverse stator windings are respectively a first reverse stator winding 5 wound on the first stator core 3 and a second reverse stator winding 10 wound on the second stator core 12, and the first reverse stator winding 5 and the second reverse stator winding 10 are connected to generate a reverse magnetic field when energized to drive the rotor winding 2 to rotate in the reverse direction. The electrode group includes a common electrode 9, a forward electrode 7 and a reverse electrode 8, wherein the common electrode 9 is connected to the first brush 1, the forward electrode 7 is connected to the second forward stator winding 11, the reverse electrode 8 is connected to the second reverse stator winding 10, and the first forward stator winding 4 and the first reverse stator winding 5 are respectively connected to the second brush 6 to control the flow of current in different directions.

[0016] The bidirectional series-excited brushed motor 15 can easily realize bidirectional rotation by designing two sets of stator windings (forward stator winding and reverse stator winding) that generate forward and reverse magnetic fields respectively. This feature makes the motor very useful in application scenarios where the direction of rotation needs to be changed frequently, such as automated production lines, robot joint drives, etc., which improves the flexibility and efficiency of the system. Winding the two sets of stator windings on two symmetrical stator cores respectively simplifies the structure and reduces the volume, which is conducive to saving space and reducing weight, which is particularly important for equipment that requires high integration or strong mobility. The bidirectional series-excited brushed motor 15 realizes effective current transmission through direct contact between the brush set and the rotor winding 2. At the same time, since the stator winding is directly wound on the stator core, the magnetic field is direct and efficient, which helps to improve the overall operating efficiency of the motor. In addition, the design of the electrode group makes it possible to control the rotation direction of the bidirectional series-excited brushed motor 15 by simply switching the current input of the forward electrode 7 and the reverse electrode 8. This control method is simple and direct, easy to implement automatic control and precise adjustment, and meets the requirements of modern industry for motor control accuracy.

[0017] In a possible embodiment, when it is necessary to control the bidirectional series-excited brushed motor 15 to rotate forward, a voltage is applied to the common electrode 9 and the forward electrode 7 so that the current flows through the common electrode 9, the first brush 1, the rotor winding 2, the second brush 6, the first forward stator winding 4, the second forward stator winding 11 in sequence, and finally flows out from the forward electrode 7, thereby generating a forward magnetic field on the stator core group and driving the rotor winding 2 to rotate forward.

[0018] In a possible embodiment, when it is necessary to control the reverse rotation of the bidirectional series-excited brushed motor 15, a voltage is applied to the common electrode 9 and the reverse electrode 8 so that the current flows through the common electrode 9, the first brush 1, the rotor winding 2, the second brush 6, the first reverse stator winding 5, the second reverse stator winding 10 in sequence, and finally flows out from the reverse electrode 8, thereby generating a reverse magnetic field on the stator core group and driving the rotor winding 2 to rotate in the reverse direction.

[0019] like Figure 4 and Figure 5 As shown, in the embodiment of the present application, a control circuit of a bidirectional series-excited brushed motor is used to drive the bidirectional series-excited brushed motor 15 as described in the embodiment of the present application, and includes a driving module 13 and a control module 14, wherein the driving module 13 includes two switch elements 16, wherein a first end of one switch element 16 is connected to a positive electrode 7 of the bidirectional series-excited brushed motor 15, and a first end of another switch element 16 is connected to a reverse electrode 8 of the bidirectional series-excited brushed motor 15. The control module 14 is respectively connected to the control ends of the two switch elements 16, and is used to control the conduction and disconnection of the two switch elements 16, thereby controlling the operation, stop and steering of the bidirectional series-excited brushed motor 15.

[0020] like Figure 5 As shown, in a possible embodiment, the two switch elements 16 are both NMOS tubes, wherein the drain of one NMOS tube is connected to the positive electrode 7 of the bidirectional series-excited brushed motor 15, and the drain of the other NMOS tube is connected to the reverse electrode 8 of the bidirectional series-excited brushed motor 15, and the sources of the two NMOS tubes are grounded; the gates of the two NMOS tubes are connected to the control module 14. The control module 14 is used to output control information to control the conduction or cutoff of the two NMOS tubes.

[0021] The drive module 13 of the bidirectional series-excited brushed motor 15 (see Figure 5 ) compared to the traditional motor drive module (see Figure 8 ) has been greatly simplified. Figure 5 As shown, the driving module 13 of the bidirectional series-excited brushed motor 15 only needs two NMOS tubes to realize the forward and reverse control of the bidirectional series-excited brushed motor 15. The bidirectional series-excited brushed motor 15 and the NMOS tubes form a "human" shape, which is referred to as a herringbone bridge.

[0022] Of course, in some other embodiments, in addition to the NMOS tube, the switch element 16 can also be a triode, a PMOS tube, a relay, etc. Although the PMOS tube complements the NMOS tube in terms of logic level, the PMOS tube is more expensive than the NMOS tube in terms of price. At the same time, in some cases, the PMOS tube may require a higher gate voltage to ensure full conduction, which may require an additional level conversion circuit, thereby increasing the cost and complexity. In addition, the relay is easily worn out during frequent switching, which affects its service life. As a solid-state device, the NMOS tube has a longer service life and higher reliability. In addition, the switching speed of the relay is slow, while the switching speed of the NMOS tube is very fast. Relays are usually larger and heavier than NMOS tubes, which may be a disadvantage in applications with limited space. In motor drive, although the triode can also adjust the collector current by controlling the base current, thereby controlling the speed and direction of the motor. However, the switching speed of the triode is relatively slow, and large switching losses may be generated in high-frequency applications. The NMOS tube is a voltage-controlled device with a very fast switching speed and relatively small power consumption during the switching process. This makes NMOS tubes perform well in applications that require high-speed switching and low power consumption. In addition, NMOS tubes also have advantages such as high input impedance and low noise, which help improve the performance of the entire circuit. Therefore, using two NMOS tubes to control the forward and reverse rotation of the bidirectional series-excited brushed motor 15 has significant advantages in terms of cost, drive complexity, switching speed and reliability.

[0023] In an embodiment of the present application, a control method for a bidirectional series-excited brushed motor is provided, using the bidirectional series-excited brushed motor 15 as described in the embodiment of the present application, and using the control circuit of the bidirectional series-excited brushed motor as described in the embodiment of the present application, and the method comprises the following steps: When the bidirectional series-excited brushed motor is controlled to rotate forward, the switch 16 connected to the forward electrode 7 of the bidirectional series-excited brushed motor 15 is controlled to be turned on by the control module 14, that is, a voltage is applied to the common electrode 9 and the forward electrode 7 of the bidirectional series-excited brushed motor 15, so that the current flows through the common electrode 9, the first brush 1, the rotor winding 2, the second brush 6, the first forward stator winding 4, the second forward stator winding 11 in sequence, and finally flows out from the forward electrode 7, thereby generating a forward magnetic field on the stator core group. At this time, the first stator core 3 generates a positive magnetic field of the N pole and the second stator core 12 generates a positive magnetic field of the S pole, driving the rotor winding 2 to rotate forward.

[0024] When the bidirectional series-excited brushed motor is controlled to rotate in reverse, the control module 14 controls the switch 16 connected to the reverse electrode 8 of the bidirectional series-excited brushed motor 15 to be turned on, and voltage is applied to the common electrode 9 and the reverse electrode 8, so that the current flows through the common electrode 9, the first brush 1, the rotor winding 2, the second brush 6, the first reverse stator winding 5, the second reverse stator winding 10 in sequence, and finally flows out from the reverse electrode 8. At this time, the first stator core 3 generates an S-pole reverse magnetic field and the second stator core 12 generates an N-pole reverse magnetic field, thereby generating a reverse magnetic field on the stator core group, driving the rotor winding 2 to rotate in reverse.

[0025] The following description is made by taking the switch element 16 as an NMOS tube as an example: When controlling the forward rotation of the bidirectional series-excited brushed motor 15, the control module 14 only needs to control the NMOS tube connected to the forward electrode 7 to be turned on and the NMOS tube connected to the reverse electrode 8 to be turned off (such as Figure 6 A voltage is applied between the common electrode 9 and the positive electrode 7, the common electrode 9 is connected to the positive electrode of the power supply, and the positive electrode 7 is connected to the negative electrode of the power supply (as shown in FIG. Figure 2 As shown in FIG. 1 , the current flows into the common electrode 9, passes through the first brush 1, the rotor winding 2, the second brush 6, the first positive stator winding 4, the second positive stator winding 11, and flows out to the positive electrode 7. At this time, the stator core group generates a positive magnetic field with the N pole on the right and the S pole on the left (as shown in FIG. 1 ). Figure 2 As shown), the rotor winding 2 is forced to rotate in the positive direction in the magnetic field.

[0026] When controlling the reverse rotation of the bidirectional series-excited brushed motor 15, the control circuit only needs to control the NMOS tube connected to the forward electrode 7 to be turned off and the NMOS tube connected to the reverse electrode 8 to be turned on (such as Figure 7 A voltage is applied between the common electrode 9 and the reverse electrode 8, the common electrode 9 is connected to the positive pole of the power supply, and the reverse electrode 8 is connected to the negative pole of the power supply (as shown in FIG. Figure 3 As shown in FIG. 1 , the current flows into the common electrode 9, passes through the first brush 1, the rotor winding 2, the second brush 6, the first reverse stator winding 5, the second reverse stator winding 10, and flows out to the reverse electrode 8. At this time, the stator core generates a reverse magnetic field with the S pole on the right and the N pole on the left (as shown in FIG. 1 ). Figure 3 As shown), the rotor winding 2 is forced to rotate in the opposite direction in the magnetic field.

[0027] The above-mentioned embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above-mentioned embodiments. Any other changes, modifications, substitutions, combinations and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement modes and shall be included in the protection scope of the present invention.

Claims

1. A bidirectional series-excited brushed motor, characterized in that: include: Rotor winding (2); A brush assembly, comprising at least a first brush (1) and a second brush (6), which are used for introducing and extracting current respectively, and realize current transmission through contact points with the rotor winding (2); A stator core assembly, comprising a first stator core (3) and a second stator core (12) symmetrically arranged outside the rotor winding (2), providing support for the stator winding and generating a magnetic field; Two sets of forward stator windings, namely a first forward stator winding (4) wound on a first stator core (3) and a second forward stator winding (11) wound on a second stator core (12), wherein the first forward stator winding (4) and the second forward stator winding (11) are connected to each other and are used to generate a forward magnetic field when power is supplied, thereby driving the rotor winding (2) to rotate in a forward direction; Two sets of reverse stator windings, namely a first reverse stator winding (5) wound on a first stator core (3) and a second reverse stator winding (10) wound on a second stator core (12), wherein the first reverse stator winding (5) and the second reverse stator winding (10) are connected to each other and are used to generate a reverse magnetic field when power is supplied, thereby driving the rotor winding (2) to rotate in the reverse direction; An electrode group comprises a common electrode (9), a forward electrode (7) and a reverse electrode (8), wherein the common electrode (9) is connected to a first brush (1), the forward electrode (7) is connected to a second forward stator winding (11), the reverse electrode (8) is connected to a second reverse stator winding (10), and the first forward stator winding (4) and the first reverse stator winding (5) are respectively connected to a second brush (6), for controlling the flow of current in different directions.

2. The bidirectional series-excited brushed motor according to claim 1, characterized in that: When the motor is controlled to rotate in the forward direction, a voltage is applied to the common electrode (9) and the forward electrode (7), so that the current flows through the common electrode (9), the first brush (1), the rotor winding (2), the second brush (6), the first forward stator winding (4), the second forward stator winding (11) in sequence, and finally flows out from the forward electrode (7), thereby generating a forward magnetic field on the stator core assembly and driving the rotor winding (2) to rotate in the forward direction.

3. The bidirectional series-excited brushed motor according to claim 1, characterized in that: When the motor is controlled to rotate in the reverse direction, a voltage is applied to the common electrode (9) and the reverse electrode (8), so that current flows through the common electrode (9), the first brush (1), the rotor winding (2), the second brush (6), the first reverse stator winding (5), the second reverse stator winding (10) in sequence, and finally flows out from the reverse electrode (8), thereby generating a reverse magnetic field on the stator core assembly and driving the rotor winding (2) to rotate in the reverse direction.

4. A control circuit for a bidirectional series-excited brushless motor, characterized in that: The control circuit is used to control the bidirectional series-excited brushed motor as claimed in any one of claims 1 to 3, and comprises: A drive module (13) comprising two switch elements (16), wherein a first end of one switch element (16) is connected to a positive electrode (7) of a bidirectional series-excited brushed motor (15), and a first end of the other switch element (16) is connected to a reverse electrode (8) of the bidirectional series-excited brushed motor (15); The control module (14) is respectively connected to the control ends of the two switch elements (16) and is used to control the conduction and disconnection of the two switch elements (16), thereby controlling the operation, stop and direction of the bidirectional series-excited brushed motor (15).

5. The control circuit of the bidirectional series-excited brushed motor according to claim 4, characterized in that: The two switch elements (16) are both NMOS tubes, wherein the drain of one NMOS tube is connected to the positive electrode (7) of the bidirectional series-excited brushed motor (15), the drain of the other NMOS tube is connected to the reverse electrode (8) of the bidirectional series-excited brushed motor (15), and the sources of the two NMOS tubes are both grounded; and the gates of the two NMOS tubes are both connected to the control module (14).

6. A control method for a bidirectional series-excited brushless motor, characterized in that: Using the bidirectional series-excited brushed motor (15) as claimed in any one of claims 1 to 3, and using the control circuit of the bidirectional series-excited brushed motor as claimed in claim 4 or 5, the method comprises the following steps: When the bidirectional series-excited brushed motor (15) is controlled to rotate in the forward direction, the switch element (16) connected to the forward electrode (7) of the bidirectional series-excited brushed motor (15) is controlled to be turned on through the control module (14), that is, a voltage is applied to the common electrode (9) and the forward electrode (7) of the bidirectional series-excited brushed motor (15), so that the current flows through the common electrode (9), the first brush (1), the rotor winding (2), the second brush (6), the first forward stator winding (4), the second forward stator winding (11) in sequence, and finally flows out from the forward electrode (7), thereby generating a forward magnetic field on the stator core group. At this time, the first stator core (3) generates a forward magnetic field with an N pole and the second stator core (12) generates a forward magnetic field with an S pole, driving the rotor winding (2) to rotate in the forward direction; When the bidirectional series-excited brushed motor (15) is controlled to rotate in reverse, the control module (14) controls the switch element (16) connected to the reverse electrode (8) of the bidirectional series-excited brushed motor (15) to be turned on, and a voltage is applied to the common electrode (9) and the reverse electrode (8), so that the current flows through the common electrode (9), the first brush (1), the rotor winding (2), the second brush (6), the first reverse stator winding (5), the second reverse stator winding (10) in sequence, and finally flows out from the reverse electrode (8). At this time, the first stator core (3) generates an S-pole reverse magnetic field, and the second stator core (12) generates an N-pole reverse magnetic field, thereby generating a reverse magnetic field on the stator core group, driving the rotor winding (2) to rotate in reverse.

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