Electric motor of composite structure

Abstract

The present invention relates to the technical field of electric motors. Particularly provided is an electric motor of a composite structure. The electric motor comprises: a first rotating shaft, a permanent-magnet inner rotor, a coil-wound inner rotor, an outer rotor, a stator and a housing, wherein the outer rotor is divided into an inner squirrel-cage winding and an outer squirrel-cage winding, and an outer-rotor support for magnetic-circuit separation is mounted between the inner squirrel-cage winding and the outer squirrel-cage winding; the permanent-magnet inner rotor can rotate about the first rotating shaft, and an axial ventilation device is mounted on one side of the permanent-magnet inner rotor; the coil-wound inner rotor is dragged to operate by a prime mover; and by means of the magnetic-circuit separation effect of the outer-rotor support, the permanent-magnet inner rotor, the coil-wound inner rotor, and the inner squirrel-cage winding of the outer rotor constitute an inner induction electric motor, and the outer squirrel-cage winding of the outer rotor and the stator constitute an outer induction electric motor. The present invention can reduce the magnitude of the current of the coil-wound inner rotor, thereby reducing the electrical wear of an electric brush and a slip ring; and the permanent-magnet inner rotor can not only increase the power factor and efficiency of the inner induction electric motor, but also effectively solve the heating problem of the rotor of the electric motor of a composite structure.

Description

A composite structure motor Technical Field

[0001] The present invention relates to the technical field of motors, and in particular to a motor with a composite structure. Background Art

[0002] Hybrid vehicles and hybrid pesticide spraying robots are currently attracting much attention for energy-saving and consumption-reducing devices, greatly facilitating people's production and daily lives. However, since these hybrid vehicles use gasoline or diesel, a non-renewable resource, continuous technological improvements are required to reduce fuel consumption and increase driving range.

[0003] The advantage of an electronically controlled continuously variable transmission, consisting of a set of planetary gears and two electric motors, is that it reduces fuel consumption and allows the internal combustion engine to always operate on the optimal fuel curve. The disadvantage of using a planetary gear structure is that it can cause a series of problems such as vibration, noise, and wear. To address this problem, composite motors with various structures have emerged. Although they eliminate the planetary gears and reduce fuel consumption, their use of brushed or magnetic gear structures inevitably causes wear on the brushes and slip rings. In addition, they have a series of problems such as high inner rotor current, low power factor, and severe rotor heating. Therefore, there is still much room for improvement in the technology of hybrid drive operation of composite motors.

[0004] Summary of the Invention

[0005] In view of this, the present invention provides a composite structure motor to reduce the wear on brushes and slip rings, reduce the magnitude of the current in the winding inner rotor, improve the power factor and efficiency of the internal induction motor, and effectively solve the heating problem of the winding inner rotor.

[0006] In a first aspect, the present invention provides a composite structure motor, comprising a prime mover and a composite structure, wherein the composite structure comprises, from the inside to the outside, a first rotating shaft, a permanent magnet inner rotor, a wound inner rotor, an outer rotor, a stator and a casing, wherein a stator is provided on the inner wall of the casing, and the stator is composed of a stator core and a stator winding; the outer rotor is arranged between the stator and the wound inner rotor, and the outer rotor comprises an outer rotor core, an inner squirrel cage winding, an outer squirrel cage winding and an outer rotor bracket, and the wound inner rotor comprises a wound inner rotor core and a wound inner rotor winding; a permanent magnet inner rotor is provided inside the wound inner rotor The permanent magnet inner rotor is composed of a permanent magnet inner rotor core and permanent magnets; there is a first air gap between the permanent magnet inner rotor and the wound inner rotor, a second air gap between the wound inner rotor and the outer rotor, and a third air gap between the outer rotor and the stator; a main bearing is installed between the casing and the first and second rotating shafts, so that the casing can rotate around the first and second rotating shafts; a secondary bearing is installed between the outer rotor bracket and the first rotating shaft, so that the outer rotor bracket can rotate; a permanent magnet inner rotor bearing is installed between the permanent magnet inner rotor and the first rotating shaft, so that the permanent magnet inner rotor can rotate around the first rotating shaft.

[0007] Optionally, the inner cage winding is installed on the side of the outer rotor core close to the second air gap, and the outer cage winding is installed on the side of the outer rotor core close to the third air gap. The inner cage winding and the outer cage winding are respectively installed on the inner and outer sides of the outer rotor bracket, and the inner cage winding and the outer cage winding are independent of each other.

[0008] Optionally, the outer rotor bracket is made of epoxy resin casting, and the outer rotor bracket can separate the magnetic circuit, so that the permanent magnet inner rotor, the wound inner rotor and the inner squirrel cage winding constitute an inner induction motor, and the outer squirrel cage winding and the stator constitute an outer induction motor.

[0009] Optionally, the wound inner rotor is driven by a prime mover, the output shaft of the prime mover is the first rotating shaft, and the outer rotor is connected to a reduction gear to drive the load to operate.

[0010] Optionally, the permanent magnets on the permanent magnet inner rotor are of surface-mounted structure and are magnetized radially. The magnetization directions of adjacent permanent magnets are opposite, and the permanent magnet inner rotor can rotate freely around the first rotating axis through the permanent magnet inner rotor bearing. An axial ventilation device is installed on one side of the permanent magnet inner rotor to dissipate heat for the wound inner rotor.

[0011] Optionally, the stator winding is a three-phase symmetrical AC winding, and the number of poles of the permanent magnet inner rotor is the same as the number of poles of the wound inner rotor.

[0012] Optionally, center lines of the stator, outer rotor, wound inner rotor and permanent magnet inner rotor are on the same straight line.

[0013] Optionally, the wound inner rotor winding is connected to brushes and slip rings in sequence, and connected to a power supply through the brushes and slip rings. The power supply consists of a rectifier inverter and a battery. The power supply can realize bidirectional flow of electric energy between the stator winding and the wound inner rotor winding.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] 1. Internal induction motors are essentially induction motors, which have a lagging power factor. Under both generating and motoring conditions, the motor's power factor can be flexibly altered by changing the winding inner rotor current under the excitation of the permanent magnet inner rotor. This allows the motor to operate in three power factor conditions: leading power factor, lagging power factor, and unity power factor. This improves the motor's power factor, allowing it to output greater drive torque under the same winding inner rotor excitation current. This makes motor control more flexible and efficient, especially under light load and low speed conditions, where the power factor and efficiency are significantly improved, achieving energy savings.

[0016] 2. In pure electric low speed, pure electric high speed, electric and prime mover hybrid power, and brake energy recovery working conditions, the permanent magnet inner rotor can participate in the excitation of the internal induction motor, thereby significantly reducing the current obtained by the inner rotor from the battery, improving the motor efficiency while also reducing the generation of electric sparks, reducing the electrical wear of the slip rings and brushes, and extending the service life of the slip rings and brushes.

[0017] 3. There is an axial ventilation device on one side of the permanent magnet inner rotor as a heat dissipation device. Under various operating modes, the permanent magnet inner rotor can be in a rotating state to perform forced axial ventilation of the internal induction motor. Since the permanent magnet inner rotor itself is idling without any load, it does not require additional power consumption, which can basically solve the technical problem of heating of the inner rotor of the composite structure motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] FIG1 is a schematic diagram of the overall structure of a composite structure motor provided by an embodiment of the present invention;

[0020] FIG2 is a schematic structural diagram of a cross-section of a composite structure provided by an embodiment of the present invention.

[0021] In the figure, 1. prime mover; 2. first rotating shaft; 3. stator; 4. load; 5. outer rotor; 6. wound inner rotor; 7. permanent magnet inner rotor; 8. reduction gear; 9. power supply; 10. axial ventilation device; 11. permanent magnet; 12. wound inner rotor winding; 13-1. outer squirrel cage winding; 13-2. inner squirrel cage winding; 14. stator winding; 15. outer rotor bracket; 16. first air gap; 17. slip ring; 18. brush; 19. casing; 20. second air gap; 21. third air gap; 22. main bearing; 23. auxiliary bearing; 24. permanent magnet inner rotor bearing; 25. second rotating shaft. DETAILED DESCRIPTION

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0023] It should be understood that the embodiments described are only a portion of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative work are within the scope of protection of the present invention.

[0024] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The singular forms "a", "an", "the" and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise.

[0025] It should be understood that the term "and / or" as used herein simply describes a relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A alone, A and B together, or B alone. Furthermore, the character " / " in this document generally indicates an "or" relationship between the associated objects.

[0026] The word "if," as used herein, may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting," depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to the determination" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)," depending on the context.

[0027] An embodiment of the present invention provides a composite structure motor, as shown in Figures 1 and 2, the composite structure motor includes: a casing 19, a stator 3 fixed to the inner wall of the casing 19, an outer rotor 5 located between the stator 3 and the wound inner rotor 6, and a permanent magnet inner rotor 7 is provided inside the wound inner rotor 6.

[0028] In the embodiment of the present invention, a first air gap 16 is formed between the permanent magnet inner rotor 7 and the wound inner rotor 6 , a second air gap 20 is formed between the wound inner rotor 6 and the outer rotor 5 , and a third air gap 21 is formed between the outer rotor 5 and the stator 3 .

[0029] In an embodiment of the present invention, the number of poles of the permanent magnet inner rotor 7 is the same as the number of poles of the wound inner rotor 6, the magnetization direction of the permanent magnets 11 in the permanent magnet inner rotor 7 is radial magnetization, the magnetization directions of adjacent permanent magnets 11 are opposite, and the permanent magnet inner rotor 7 can rotate freely around the first rotating shaft 2 through the permanent magnet inner rotor bearing 24, and an axial ventilation device 10 is installed on one side of the permanent magnet inner rotor 7.

[0030] A magnetically isolated outer rotor support 15 is installed between outer cage winding 13-1 and inner cage winding 13-2. Through the magnetic circuit separation effect of outer rotor support 15, permanent magnet inner rotor 7, wound inner rotor 6, and inner cage winding 13-2 form an inner induction motor, while outer cage winding 13-1 and stator 3 form an outer induction motor.

[0031] Stator 3 includes an iron core and stator winding 14. Outer rotor 5 includes an iron core, outer cage winding 13-1, inner cage winding 13-2, and outer rotor bracket 15. Wound inner rotor 6 includes a wound inner rotor iron core and wound inner rotor winding 12. Permanent magnet inner rotor 7 includes an iron core and permanent magnets 11. Both stator winding 14 and wound inner rotor winding 12 are three-phase symmetrical AC windings.

[0032] The stator core, outer rotor core, inner rotor core and permanent magnet inner rotor core are all made of silicon steel sheets or other magnetic conductive materials, and the manufacturing process is the same as that of ordinary motors.

[0033] A main bearing 22 is installed between the housing 19 and the first rotating shaft 2 and the second rotating shaft 25, so that the housing 19 can rotate around the first rotating shaft 2 and the second rotating shaft 25; a secondary bearing 23 is installed between the outer rotor bracket 15 and the first rotating shaft 2 so that the outer rotor bracket 15 can rotate; a permanent magnet inner rotor bearing 24 is installed between the permanent magnet inner rotor 7 and the first rotating shaft 2, so that the permanent magnet inner rotor 7 can rotate around the first rotating shaft 2.

[0034] In the embodiment of the present invention, the composite structure is adopted, which helps to simplify the control algorithm and also helps to save energy and maintenance costs.

[0035] An embodiment of the present invention provides a method for operating a composite structure motor, wherein a stator winding 14 and a wound inner rotor winding 12 of a composite structure motor are connected to a power supply 9, and the stator winding 14 and the wound inner rotor winding 12 can complete a bidirectional flow of electrical energy with the power supply 9.

[0036] A wound inner rotor 6 of a composite structure motor is connected to a power source 9 via brushes 18 and slip rings 17 .

[0037] The wound inner rotor 6 is driven by the prime mover 1 to run, and the outer rotor 5 is connected to the reduction gear 8 through the second rotating shaft 25 to drive the load 4 to run.

[0038] It can realize three modes: driving the inner induction motor alone, driving the outer induction motor alone, and driving the inner and outer induction motors together. It can also realize regenerative braking function under braking conditions.

[0039] During pure electric low-speed operation, the power supply 9 supplies three-phase AC power to the stator winding 14 of the external induction motor, generating an alternating rotating magnetic field. At this time, the electromagnetic torque generated by electromagnetic induction between the stator 3 and the outer squirrel cage winding 13-1 causes the rotor to begin to rotate. The electromagnetic torque drives the outer rotor 5 to rotate, generating a driving effect on the load 4. At this time, the stator 3 and the outer squirrel cage winding 13-1 constitute the external induction motor, and the internal induction motor does not work.

[0040] During pure electric high-speed operation, two drive options are available. One is that power supply 9 supplies three-phase AC power to the wound inner rotor winding 12. The wound inner rotor 6 and inner cage winding 13-2 form an inner induction motor. Simultaneously, the permanent magnet inner rotor 7 is permanently excited, generating electromagnetic torque that drives the outer rotor 5 at high speed. In this case, the inner induction motor is driven alone. The other is that power supply 9 supplies power to the wound inner rotor winding 12. Simultaneously, the inner permanent magnet rotor 7 is permanently excited. The wound inner rotor 6 and inner cage winding 13-2 form an inner induction motor. Simultaneously, power supply 9 supplies power to the outer induction motor stator winding 14. The stator 3 and outer cage winding 13-1 form an outer induction motor. Both the inner and outer induction motors generate electromagnetic torque that drives the outer rotor 5 at high speed. In this case, both the inner and outer induction motors are driven simultaneously.

[0041] When the electric and prime mover 1 are in hybrid operation, in addition to the external induction motor drive, the power supply 9 supplies power to the wound inner rotor winding 12. The prime mover 1 runs to transmit power to the wound inner rotor 6. The wound inner rotor 6 rotates, and the magnetic fields between the wound inner rotor winding 12 and the inner squirrel cage winding 13-2 interact with each other. At the same time, the inner permanent magnet rotor 7 is permanently magnetized, and the electromagnetic torque generated by the internal induction motor and the external induction motor is transmitted to the outer rotor 5.

[0042] During the braking energy recovery process, the outer induction motor transforms into a generator. The outer cage winding 13-1 acts as a rotor, absorbing the rotational mechanical energy of the load 4. This energy is induced in the stator 3 to charge the power supply 9. Simultaneously, the inner induction motor also transforms into a generator. The inner cage winding 13-2 acts as a rotor, absorbing the rotational mechanical energy of the load 4. This energy is induced in the wound rotor to charge the power supply 9. The absorbed braking energy is converted into electrical energy in the wound rotor, which charges the power supply 9. During the power generation process of the inner induction motor, the permanent magnet inner rotor 7 also rotates, participating in the excitation of the power generation process.

[0043] In the technical solution of the present invention:

[0044] 1. Internal induction motors are essentially induction motors, which have a lagging power factor. Under both generating and motoring conditions, the power factor of an internal induction motor can be flexibly altered by varying the winding inner rotor current under the excitation of the permanent magnet inner rotor 7. This allows the motor to operate in three power factor conditions: leading power factor, lagging power factor, and unity power factor. This improves the power factor of the internal induction motor and allows it to output greater drive torque under the same winding inner rotor excitation current. This makes motor control more flexible and efficient, particularly under light load and low speed conditions, where the power factor and efficiency are significantly improved, achieving energy savings.

[0045] Second, in operating conditions such as pure electric low speed, pure electric high speed, electric and prime mover hybrid power, and brake energy recovery, the permanent magnet inner rotor 7 can participate in the excitation of the internal induction motor, thereby significantly reducing the current drawn by the inner rotor from the battery, improving the motor efficiency while also reducing the generation of electric sparks, reducing the electrical wear of the slip ring 17 and the brush 18, and extending the service life of the slip ring and the brush.

[0046] 3. An axial ventilation device 10 is provided on one side of the permanent magnet inner rotor 7 as a heat dissipation device. Under various operating modes, the permanent magnet inner rotor 7 can be in a rotating state, performing mandatory axial ventilation of the internal induction motor. Since the permanent magnet inner rotor 7 itself is idling without any load, no additional power consumption is required, which can basically solve the technical problem of heating of the inner rotor of the composite structure motor.

[0047] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0048] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A composite structure motor, comprising a prime mover (1) and a composite structure, characterized in that: The composite structure comprises, from inside to outside, a first rotating shaft (2), a permanent magnet inner rotor (7), a wound inner rotor (6), an outer rotor (5), a stator (3) and a casing (19). The stator (3) is arranged on the inner wall of the casing (19), and the stator (3) is composed of a stator core and a stator winding (14). The outer rotor (5) is arranged between the stator (3) and the wound inner rotor (6), and the outer rotor (5) comprises an outer rotor core, an inner layer squirrel cage winding (13-2), an outer layer squirrel cage winding (13-1) and an outer rotor support (15). The wound inner rotor (6) comprises a wound inner rotor core and a wound inner rotor winding (12). The wound inner rotor (6) is provided with a permanent magnet inner rotor (7), and the permanent magnet inner rotor (7) is composed of a permanent magnet inner rotor core and a permanent magnet (11 );a first air gap (16) is formed between the permanent magnet inner rotor (7) and the wound inner rotor (6), a second air gap (20) is formed between the wound inner rotor (6) and the outer rotor (5), and a third air gap (21) is formed between the outer rotor (5) and the stator (3); a main bearing (22) is installed between the housing (19) and the first rotating shaft (2) and the second rotating shaft (25), so that the housing (19) can rotate around the first rotating shaft (2) and the second rotating shaft (25); a secondary bearing (23) is installed between the outer rotor support (15) and the first rotating shaft (2), so that the outer rotor support (15) can rotate; a permanent magnet inner rotor bearing (24) is installed between the permanent magnet inner rotor (7) and the first rotating shaft (2), so that the permanent magnet inner rotor (7) can rotate around the first rotating shaft (2).

2. The composite structure motor according to claim 1, characterized in that: The inner cage winding (13-2) is installed on the side of the outer rotor core close to the second air gap (20), and the outer cage winding (13-1) is installed on the side of the outer rotor core close to the third air gap (21). The inner cage winding (13-2) and the outer cage winding (13-1) are installed on the inner and outer sides of the outer rotor bracket (15), respectively, and the inner cage winding (13-2) and the outer cage winding (13-1) are independent of each other.

3. The composite structure motor according to claim 1, characterized in that: The material of the outer rotor support (15) is epoxy resin casting, and the outer rotor support (15) can separate the magnetic circuit, so that the permanent magnet inner rotor (7), the wound inner rotor (6) and the inner layer squirrel cage winding (13-2) form an inner induction motor, and the outer layer squirrel cage winding (13-1) and the stator (3) form an outer induction motor.

4. The composite structure motor according to claim 1, characterized in that: The winding inner rotor (6) is driven by a prime mover (1) and the output shaft of the prime mover is a first rotating shaft (2). The outer rotor (5) is connected to a reduction gear (8) to drive a load (4) to operate.

5. The composite structure motor according to claim 1, characterized in that: The permanent magnets (11) on the permanent magnet inner rotor (7) are of a surface-mounted structure and are magnetized in the radial direction. The magnetization directions of adjacent permanent magnets (11) are opposite. The permanent magnet inner rotor (7) can rotate around the first rotating shaft (2) via a permanent magnet inner rotor bearing (24). An axial ventilation device (10) is installed on one side of the permanent magnet inner rotor (7) to dissipate heat for the wound inner rotor (6).

6. The composite structure motor according to any one of claims 1 or 2, characterized in that: The stator winding (14) is a three-phase symmetrical AC winding, and the number of poles of the permanent magnet inner rotor (7) is the same as the number of poles of the wound inner rotor (6).

7. The composite structure motor according to any one of claims 1 or 2, characterized in that: The center lines of the stator (3), the outer rotor (5), the wound inner rotor (6) and the permanent magnet inner rotor (7) are on the same straight line.

8. The composite structure motor according to any one of claims 1 or 2, characterized in that: The wound inner rotor winding (12) is connected to a brush (18) and a slip ring (17) in sequence, and is connected to a power source (9) via the brush (18) and the slip ring (17). The power source (9) is composed of a rectifier inverter and a battery. The power source (9) can realize a bidirectional flow of electric energy with the stator winding (14) and the wound inner rotor winding (12).

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