Radial magnetic field compound dual power flow motor

Abstract

The present invention relates to the field of motor design, and discloses a radial magnetic field composite dual-power flow motor, comprising a rotor output shaft, a stationary shaft coaxially connected to the stationary shaft, an inner stator surrounding the stationary shaft, an inner rotor surrounding the inner stator, a magnetic isolation ring surrounding the inner rotor, an outer rotor surrounding the magnetic isolation ring, and an outer stator surrounding the outer rotor; air gaps are provided between the outer stator and the outer rotor and between the inner stator and the inner rotor; the outer rotor is fixedly connected to the inner rotor through the magnetic isolation ring, and the outer rotor, the magnetic isolation ring, the inner rotor and the rotor bracket constitute the motor rotor; the stationary shaft is fixedly connected to the inner stator and the outer shell, and is rotationally connected to the motor rotor and the outer stator; one end of the rotor output shaft is fixedly connected to the motor rotor, and the other end is rotationally connected to the stator bracket. The present invention meets the requirements of low-speed, high-torque and wide speed regulation range operation of the drive motor under the premise of improving the operating reliability of the permanent magnet and avoiding irreversible demagnetization of the permanent magnet due to weak magnetic speed regulation and high temperature.

Description

Technical Field

[0001] The invention relates to the field of motor design, and in particular to a radial magnetic field composite dual-power flow motor. Background Art

[0002] High torque density, low speed and high torque, and wide speed range are the performance requirements of drive motors, especially direct drive motors. The widely used switched reluctance motor has a wide speed range and a simple structure. There are no permanent magnets on the stator and rotor, and the working reliability is high. However, its torque density is significantly lower than that of permanent magnet motors. In recent years, stator permanent magnet motors have been widely studied due to their high torque density and high efficiency. In this motor structure, permanent magnets and windings are placed on the stator, and the rotor structure is simple, which improves the reliability and dynamic operation performance of the motor. However, due to the inherent characteristics of permanent magnets, the air gap magnetic field of the stator permanent magnet motor remains basically constant during operation. During electric operation, the motor excitation control is difficult and the speed range is limited. Scholars often use hybrid excitation to increase the speed range of stator permanent magnet motors. In addition to permanent magnets, excitation windings are also set on the stator to realize dual excitation source hybrid excitation, which can improve the magnetic field regulation capability and widen the speed operation range. However, the high-speed weak magnetic speed regulation in the motor speed regulation process will reduce the working performance of the permanent magnet, and in severe cases, lead to irreversible demagnetization of the permanent magnet. In addition, in the structure of the hybrid excitation stator permanent magnet motor, the stator has both permanent magnets and two sets of windings (excitation winding and armature winding). On the one hand, the magnetic circuit saturation is high, and on the other hand, the armature winding placement space is constrained, which limits the torque output capacity to a certain extent. Moreover, since the heat source is located in the stator, it is easy to cause the stator winding and permanent magnet temperature to rise too high, resulting in winding insulation damage and irreversible demagnetization of the permanent magnet. Summary of the invention

[0003] Purpose of the invention: In view of the problems existing in the prior art, the present invention provides a radial magnetic field composite dual-power flow motor, which meets the requirements of low-speed, high-torque and wide speed regulation range operation of the drive motor while improving the operating reliability of the permanent magnet and avoiding irreversible demagnetization of the permanent magnet due to weak magnetic speed regulation.

[0004] Technical solution: The present invention provides a radial magnetic field composite dual-power flow motor, including a rotor output shaft, a stationary shaft coaxially connected to the rotor output shaft, an inner stator surrounding the stationary shaft, an inner rotor surrounding the inner stator, a magnetic isolation ring surrounding the inner rotor, an outer rotor surrounding the magnetic isolation ring, and an outer stator surrounding the outer rotor; air gaps are provided between the outer stator and the outer rotor and between the inner stator and the inner rotor; the outer rotor is fixedly connected to the inner rotor through the magnetic isolation ring, and the outer rotor, the magnetic isolation ring, the inner rotor and the rotor bracket constitute the motor rotor; the stationary shaft is fixedly connected to the inner stator and the outer casing, rotationally connected to the motor rotor, and rotationally connected to the outer stator; one end of the rotor output shaft is fixedly connected to the motor rotor, and the other end is rotationally connected to the stator bracket.

[0005] Furthermore, salient pole teeth and excitation devices are provided on the opposite sides of the outer stator and the outer rotor, and on the opposite sides of the inner stator and the inner rotor, and outer windings are provided on the salient pole teeth of the outer stator, and inner windings are provided on the salient pole teeth of the inner stator.

[0006] Preferably, the magnetizing direction of the excitation device is alternating magnetizing tangentially along the circumference of the outer stator.

[0007] Preferably, the excitation device is a permanent magnet or a hybrid excitation device. When a hybrid excitation device is used, the electric excitation source is only used to increase the output torque capacity during low-speed magnetization, and there is no high-speed weak magnetic working mode.

[0008] Preferably, the number of salient pole teeth of the outer stator is P so , the outer winding consists of symmetrically distributed P so The outer winding is composed of a coil sleeved on the salient pole teeth of the outer stator. m Phase concentrated winding, meet P so =2 k 1 m , where k 1 A positive integer; the number of teeth of the salient pole teeth of the outer rotor is P ro ,satisfy P ro = P so ±2N 1 , where N 1 Is a positive integer.

[0009] Preferably, the number of teeth of the inner stator salient pole teeth is P si, the inner winding consists of symmetrically distributed P si The inner winding is composed of a coil sleeved on the salient pole teeth of the inner stator. n Phase concentrated winding, meet P si =2 k 2 n , where k 2 A positive integer; the number of salient pole teeth of the inner rotor is P ri ,satisfy P ri = P si ±2N 2 , where N 2 Is a positive integer.

[0010] Preferably, the salient pole teeth on the outer stator, the outer rotor, the inner stator and the inner rotor are all oriented in the radial direction.

[0011] Preferably, both the inner winding and the outer winding are multi-phase concentrated armature windings.

[0012] Preferably, one end of the rotor output shaft is fixedly connected to the rotor bracket of the motor rotor, and the other end is rotatably connected to the stator bracket via a first bearing.

[0013] Preferably, the stationary shaft is rotatably connected to the stator support of the outer stator via a second bearing, and is rotatably connected to the rotor support of the motor rotor via a third bearing and a fourth bearing.

[0014] Beneficial effects: In the radial magnetic field composite dual-power flow motor of the present invention, the outer stator and the outer rotor constitute the outer motor, and the inner stator and the inner rotor constitute the inner motor. The inner and outer motors are completely independent, without electromagnetic coupling, and can therefore be independently controlled. There are a variety of motor structure options for the inner and outer motors, such as the outer motor can adopt a double-pole permanent magnet motor and a flux reversal motor. It should be pointed out that the stator and rotor tooth slot matching, phase number and excitation method of the inner and outer motors of the radial magnetic field composite motor proposed in the present invention can be flexibly adjusted according to the system performance requirements.

[0015] In the present invention, the inner stator is fixedly connected to the stationary shaft and the outer shell and does not rotate, and the outer stator is rotationally connected to the stationary shaft through the second bearing and can rotate at a certain speed during operation. In addition, the outer rotor is fixedly connected to the inner rotor through a magnetic isolation ring, and the outer rotor, the magnetic isolation ring, the inner rotor and the rotor bracket constitute the motor rotor. One end of the rotor output shaft is fixed to the motor rotor and is rotationally connected to the outer stator bracket through the first bearing, and the stationary shaft is rotationally connected to the motor rotor through the third bearing and the fourth bearing.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] 1. In the present invention, the inner motor mainly realizes the speed regulation of the motor according to the load speed requirement, so that the rotor output shaft rotates at the target speed; the role of the outer motor is to provide driving torque or braking torque according to the load requirement to make up for the lack of output torque of the inner motor. During the operation of the motor, the outer stator can rotate differentially with the outer rotor, so that the outer motor always works near the rated point with higher efficiency, and thus has a larger torque output capacity. Whether it is running at low speed or high speed, the lack of output torque of the inner motor can be provided by the outer motor, thereby realizing the requirements of low-speed, high-torque and wide speed regulation range operation of the motor.

[0018] 2. The present invention has no permanent magnets on the inner stator and the inner rotor, thus avoiding the irreversible demagnetization of the permanent magnets due to the difficulty in heat dissipation of the inner motor at high temperature; the outer motor is provided with an excitation device to increase the torque output capacity, and the excitation device in the outer motor only works in the magnetization mode and does not participate in the weak magnetic speed regulation. Under high-speed conditions, the inner motor realizes speed regulation. Due to the effect of the second bearing on the outer stator, the outer stator of the outer motor can always work near the rated point through differential rotation when the rotor rotates at high speed, completing the increase in torque output while avoiding the risk of irreversible demagnetization of the permanent magnets caused by the weak magnetic speed regulation of the outer motor; from the above two points of view, the present invention improves the working stability of the permanent magnets and the reliability of the motor operation.

[0019] 3. The inner motor and the outer motor in the present invention can operate in different working modes such as individual drive or common drive. When one motor fails, the other motor can be operated independently for a short time. Therefore, the motors in the present invention have a certain fault tolerance. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a cross-sectional view of a radial magnetic field composite dual power flow motor with an inner motor of 3-phase stator 12 slots / rotor 8 poles and an outer motor of 3-phase stator 12 slots / rotor 22 poles.

[0021] Figure 2 It is a cross-sectional view of the radial magnetic field composite dual-power flow motor of the present invention.

[0022] In the figure: 1 outer stator, 2 outer rotor, 3 inner rotor, 4 inner stator, 5 stationary shaft, 1-1 outer winding, 1-2 excitation device, 2-3 magnetic isolation ring, 4-1 inner winding, 6 rotor output shaft, 7 first bearing, 8 second bearing, 9 third bearing, 10 fourth bearing, 11 stator bracket, 12 rotor bracket, 13 casing. DETAILED DESCRIPTION

[0023] The present invention is described in detail below in conjunction with the accompanying drawings.

[0024] This embodiment provides a radial magnetic field compound dual-power flow motor, such as Figure 1 , mainly comprising a stationary shaft 5, an inner stator 4 surrounding the stationary shaft 5, an inner rotor 3 surrounding the inner stator 4, a magnetic isolation ring 2-3 surrounding the inner rotor 3, an outer rotor 2 surrounding the magnetic isolation ring 2-3, and an outer stator 1 surrounding the outer rotor 2. An air gap is provided between the outer stator 1 and the outer rotor 2, an air gap is provided between the inner stator 4 and the inner rotor 3, and salient pole teeth without windings are provided on the radial side of the outer rotor 2 facing the outer stator 1 and the radial side of the inner rotor 3 facing the inner stator 4. Salient pole teeth and outer windings 1-1 wound on the salient pole teeth are provided on the radial inner side of the outer stator 1, and salient pole teeth and inner windings 4-1 wound on the salient pole teeth are provided on the radial outer side of the inner stator 4. The salient pole teeth of the outer stator 1 are provided with an excitation device 1-2, and the magnetization direction of the excitation device 1-2 is alternating magnetization along the circumference of the outer stator 1. The excitation device 1-2 in this embodiment uses a permanent magnet, and of course a hybrid excitation device can also be used. It should be pointed out that in this embodiment, the directions of the salient poles of the stator and the rotor are all in the radial direction.

[0025] like Figure 1 This embodiment takes a radial magnetic field composite dual-power flow motor with an inner motor of 3-phase stator 12 slots / rotor 8 poles and an outer motor of 3-phase stator 12 slots / rotor 22 poles as an example to specifically illustrate the technical solution of the present invention.

[0026] The inner stator 4 has 12 salient pole teeth protruding radially outward from the yoke, on which there are no permanent magnets. The 12 salient pole teeth are covered with 12 armature winding coils, and every 4 coils are connected in series to form a concentrated winding, thereby forming a three-phase inner armature winding, i.e., the inner winding 4-1. The number of salient pole teeth of the inner rotor 3 is 8. The inner stator 4, the inner rotor 3 and the inner winding 4-1 thereon form a three-phase 12 / 8-pole switched reluctance inner motor; the outer stator 1 has 12 core groove units and 12 rectangular permanent magnets distributed along the circumference. The magnets 1-2 are placed alternately adjacent to each other to form 12 outer stator poles. Each outer stator pole is composed of a permanent magnet and two adjacent outer stator teeth of the core groove unit on both sides of its circumference. The core groove unit opens toward the outer rotor 2. The outer rotor 2 has 22 salient pole teeth. There are 12 winding coils wound around the 12 outer stator poles of the outer stator 1, of which every 4 winding coils form a phase concentrated winding, thus forming an outer three-phase concentrated armature winding, i.e., the outer winding 1-1. The outer rotor 2, the outer stator 1, the permanent magnets 1-2 thereon, and the outer winding 1-1 form a three-phase 12 / 22-pole permanent magnet flux switching outer motor structure.

[0027] See Figure 2The inner stator 4 is fixedly connected to the stationary shaft 5 and the outer shell 13, the outer rotor 2 is fixedly connected to the inner rotor 3 through the magnetic isolation ring 2-3, the outer rotor 2, the magnetic isolation ring 2-3, the inner rotor 3, and the rotor bracket 12 constitute the motor rotor, the stationary shaft 5 is rotatably connected to the motor rotor through the third bearing 9 and the fourth bearing 10, and is rotatably connected to the outer stator 1 through the second bearing 8, one end of the rotor output shaft 6 is fixed on the motor rotor, and is rotatably connected to the stator bracket 11 through the first bearing 7.

[0028] The radial magnetic field composite dual-power flow motor is divided into two parts based on the functions that can be realized: one part is the speed-regulating inner motor, which adopts a three-phase 12 / 8-pole switched reluctance structure, has a simple structure, is suitable for high-speed operation, is easy to cool, and can allow a higher temperature rise due to the absence of permanent magnets; the other part is the torque-regulating outer motor, which adopts a three-phase 12 / 22-pole permanent magnet flux switching motor, has a simple rotor structure, and has high torque density and high efficiency. Since the outer rotor 2 and the inner rotor 3 are both fixedly connected to the rotor output shaft 6, the inner motor and the outer motor have the same rotor speed, the inner stator 4 is fixedly connected to the stationary shaft 5, and has no speed, while the outer stator 1 can rotate at a certain speed according to the working conditions due to the presence of the first bearing 7 and the second bearing 8. In the present invention, the inner motor mainly realizes the speed regulation of the motor according to the load speed requirement, so that the rotor output shaft 6 rotates at the target speed and outputs a certain torque at the same time; the role of the outer motor is to provide driving torque or braking torque according to the load requirements to make up for the lack of output torque of the inner motor. In specific operation, the outer stator 1 can rotate in the same direction with the outer rotor 2 at a differential speed, so that the outer motor always works near the rated point with higher efficiency. There is no permanent magnet in the inner motor, so the permanent magnet weak magnetic field is not used to achieve speed regulation in the speed regulation operation of the motor, which helps to reduce the cost of the motor and improve the reliability of the operation of the inner motor. The outer motor adopts a permanent magnet motor structure with a magnetic field concentration effect to achieve high torque density and high efficiency, and has a large torque regulation ability. Due to the role of the first bearing 7 and the second bearing 8, the outer motor can always work near the rated point under different working conditions, and whether it is running at low speed or high speed, the lack of output torque of the inner motor can be provided by the outer motor, thereby realizing the requirements of low-speed, high-torque and wide speed regulation range operation of the motor.

[0029] There is no electromagnetic coupling between the inner and outer motor systems of this radial magnetic field composite dual-power flow motor, and they can be independently controlled as two ordinary motors. The controllable parameters are much more than those of ordinary flux switching motors, which is very flexible. The inner and outer motors can operate in different working modes such as single-machine drive, dual-machine joint drive, and dual-machine power generation according to different working conditions. When both the inner and outer motors are used for power generation, they can output two sets of electric energy with different power, frequency, amplitude and voltage levels; the inner and outer motor systems can also be used for power generation and electric operation by one, to meet different application occasions and performance requirements.

[0030] The radial magnetic field composite dual power flow motor integrates the permanent magnet flux switching outer motor and the switched reluctance inner motor in a radial magnetic field motor space, providing two power flow paths. Both the inner motor and the outer motor can adopt other motor structures, which greatly improves the flexibility of the system and expands the scope of application.

[0031] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent transformation or modification made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A radial magnetic field compound dual-power flow machine, characterized in that: It comprises a stationary shaft (5), a rotor output shaft (6) coaxially connected to the stationary shaft (5) and rotating around the stationary shaft (5), an inner stator (4) surrounding the stationary shaft (5), an inner rotor (3) surrounding the inner stator (4), a magnetic isolation ring (2-3) surrounding the inner rotor (3), an outer rotor (2) surrounding the magnetic isolation ring (2-3), and an outer stator (1) surrounding the outer rotor (2); air gaps are provided between the outer stator (1) and the outer rotor (2) and between the inner stator (4) and the inner rotor (3); The outer rotor (2) is fixedly connected to the inner rotor (3) via the magnetic isolation ring (2-3), and the outer rotor (2), the magnetic isolation ring (2-3), the inner rotor (3) and the rotor bracket (12) constitute the motor rotor; the stationary shaft (5) is fixedly connected to the inner stator (4) and the outer shell (13), the motor rotor is rotationally connected around the stationary shaft (5), and the outer stator (1) is rotationally connected around the stationary shaft (5); one end of the rotor output shaft (6) is fixedly connected to the motor rotor, and the other end is rotationally connected to the stator bracket (11); One end of the rotor output shaft (6) is rotatably connected to the stator support (11) via a first bearing (7), and the stator support (11) is rotatably connected around a stationary shaft (5) via a second bearing (8); and there are no permanent magnets on the inner stator (4) and the inner rotor (3).

2. The radial magnetic field compound dual-power flow motor according to claim 1, characterized in that: The opposite sides of the outer stator (1) and the outer rotor (2) and the opposite sides of the inner stator (4) and the inner rotor (3) are both provided with salient pole teeth, and the salient pole teeth of the outer stator (1) are provided with outer windings (1-1) and excitation devices (1-2), and the salient pole teeth of the inner stator (4) are provided with inner windings (4-1).

3. The radial magnetic field compound dual-power flow motor according to claim 2, characterized in that: The magnetizing direction of the excitation device (1-2) is alternating magnetization along the circumferential tangent of the outer stator (1).

4. The radial magnetic field compound dual-power flow motor according to claim 2, characterized in that: The excitation device (1-2) is a permanent magnet or a hybrid excitation device.

5. The radial magnetic field compound dual-power flow motor according to claim 2, characterized in that: The number of salient pole teeth of the outer stator (1) is P so , the outer winding (1-1) consists of symmetrically distributed P so The outer winding (1-1) is composed of a coil sleeved on the salient pole teeth of the outer stator (1). m Phase concentrated winding, meet P so =2 k 1 m , where k 1 positive integer; The number of salient pole teeth of the outer rotor (2) is P ro ,satisfy P ro = P so ±2N1, where N1 is a positive integer.

6. The radial magnetic field compound dual-power flow motor according to claim 5, characterized in that: The number of salient pole teeth of the inner stator (4) is P si , the inner winding (4-1) consists of symmetrically distributed P si The inner winding (4-1) is composed of a coil sleeved on the salient pole teeth of the inner stator. n Phase concentrated winding, meet P si =2 k 2 n , where k 2 positive integer; The number of teeth of the salient pole teeth of the inner rotor (3) is P ri ,satisfy P ri = P si ±2N2, where N2 is a positive integer.

7. The radial magnetic field compound dual-power flow machine according to any one of claims 1 to 6, characterized in that: The salient pole teeth on the outer stator (1), the outer rotor (2), the inner stator (4) and the inner rotor (3) are all oriented in the radial direction.

8. The radial magnetic field compound dual-power flow motor according to claim 2, characterized in that: The inner winding (4-1) and the outer winding (1-1) are both multi-phase concentrated armature windings.

9. The radial magnetic field compound dual-power flow machine according to any one of claims 1 to 6, characterized in that: The other end of the rotor output shaft (6) is fixedly connected to a rotor support (12) of the motor rotor.

10. The radial magnetic field compound dual-power flow machine according to any one of claims 1 to 6, characterized in that: The rotor support (12) of the motor rotor is rotatably connected around the stationary axis (5) via a third bearing (9) and a fourth bearing (10).

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