Four-phase double-stator doubly salient motor

Abstract

The present invention relates to the field of motor technology, and in particular to a four-phase dual-stator double-salient pole motor, comprising a coaxially arranged outer stator, a rotor and an inner stator, and is characterized in that the outer stator comprises an outer stator core yoke, outer stator core teeth and an armature winding, and outer stator tooth slots are provided between adjacent outer stator core teeth; the rotor comprises a plurality of rotor core blocks and a non-magnetic connection structure filled between the rotor core blocks; the inner stator comprises an annular inner stator core; an excitation winding is provided in the outer stator tooth slot of every four outer stator core teeth, or a permanent magnet is embedded in the inner stator core radially corresponding to the outer stator tooth slot; the permanent magnet and the excitation winding are both excitation devices, and the number of the excitation devices is N. pm =2k, the number of teeth of the outer stator core N s =8k, the number of rotor core blocks N r =6k or 10k, where k is a positive integer. This motor can effectively solve the low torque density problem existing in traditional structures and reduce the risk of thermal demagnetization of permanent magnets.

Description

Technical field

[0001] The present invention belongs to the technical field of motors, and in particular relates to a four-phase dual-stator double-salient-pole motor. [Background Technology]

[0002] The doubly salient permanent magnet motor is a stator-type permanent magnet motor. Compared with the traditional three-phase six-stator slot four-rotor tooth motor, the four-phase eight-stator slot six-rotor tooth motor has obvious advantages, such as higher power density, wider speed range, smaller torque ripple and lower current amplitude. Therefore, it has received widespread attention from people in the electrical engineering field.

[0003] However, the permanent magnets and armature windings of this type of motor are placed on the stator, which will result in insufficient utilization of the internal space of the motor, causing the motor's torque output capacity to remain poor, thereby limiting the promotion and application of this type of motor in the industrial field.

[0004] For example, Chinese patent publication number CN102130564A discloses a four-phase doubly salient-pole motor consisting of a stator and rotor mounted on the same shaft. The stator has 8n salient-pole teeth evenly distributed. Every fourth salient-pole tooth slot on the stator houses an excitation winding or a permanent magnet. Furthermore, each stator salient-pole tooth is fitted with a concentrated armature winding. The armature windings on salient-pole teeth at the same position in the magnetic field are connected in series to form a single-phase winding. The rotor has 6n rotor poles evenly distributed, where n is a positive integer and n ≥ 1. This motor unit has an 8 / 6 structure, with a stator pole pitch that is three times the stator pole arc length and a rotor pole width that is equal to or greater than the stator pole width. When the rotor poles are widened to a pole arc coefficient of 1 / 3, the motor achieves maximum output power when used as a generator. Compared to a corresponding three-phase 6n / 4n-pole doubly salient-pole motor of the same size, this technical invention offers higher power density, lower winding copper losses, a wider speed regulation range, and lower torque ripple. However, the motor described in the prior invention has the following shortcomings:

[0005] 1) Sinusoidal alternating current flows through the armature winding, generating copper loss. The heat is mainly conducted through the stator core. The permanent magnets are embedded in the stator core yoke and must simultaneously withstand their own eddy current loss heat and the heat conducted to the stator core by the windings. This greatly increases the risk of thermal demagnetization of the permanent magnets.

[0006] 2) The rotor only has a rotor yoke and salient pole rotor teeth, and the internal space utilization of the motor is not high.

[0007] 3) The size of the permanent magnet in the tangential magnetization direction is adjustable, but the size in the radial direction is limited by the thickness of the stator core yoke. The excitation amount is not easy to select and it is not easy to accommodate more excitation, which limits the torque output capacity of the motor.

[0008] 4) The permanent magnets and armature windings are located on the stator core yoke and stator core teeth respectively. There is a spatial competition between the two, resulting in competition between the electric load and the magnetic load, which in turn limits the torque output capacity of the motor.

[0009] 5) The permanent magnets are embedded in the outer stator core, while the armature coils are wound around the inner stator core teeth. This underutilizes the excellent heat dissipation capabilities of the outer casing. In particular, the armature coils, when supplied with alternating current, generate copper loss and generate significant heat. Even with a heat sink, this heat is difficult to dissipate within the motor, posing a risk of damaging the copper wire insulation. Given the same insulation level, the electrical load is limited, which in turn constrains the motor's torque output. [Summary of the invention]

[0010] Based on the shortcomings of the existing technology, the present invention provides a four-phase dual-stator double-salient pole motor, which can better solve the low torque density problem existing in the traditional structure. At the same time, it can also reduce the risk of thermal demagnetization of permanent magnets and achieve better heat dissipation effect.

[0011] To achieve the above-mentioned objectives, the present invention provides the following technical solutions: a four-phase dual-stator double-salient-pole motor, comprising an outer stator, a rotor and an inner stator coaxially arranged in sequence from the outside to the inside, the outer stator comprising an outer stator core yoke, outer stator core teeth uniformly fixed circumferentially on the inner side of the outer stator core yoke and an armature winding wound on the outer stator core teeth, with outer stator tooth slots being provided between adjacent outer stator core teeth; the rotor comprising a plurality of arc-shaped rotor core blocks and a non-magnetic connection structure filled between two adjacent rotor core blocks; the inner stator comprising an annular inner stator core; an excitation winding is provided in the outer stator tooth slot of every four outer stator core teeth, or a permanent magnet is embedded in the inner stator core radially corresponding to the outer stator tooth slot, and the polarities of adjacent excitation windings are opposite, and the excitation windings are connected in series with each other, wherein the number of excitation windings and permanent magnets is an even number; the permanent magnets and excitation windings are both excitation devices, and the number of excitation devices is N. pm =2k, the number of teeth of the outer stator core N s =8k, the number of rotor core blocks N r =6k or 10k, where k is a positive integer. The number of outer stator core teeth sandwiched between the radial axes of two adjacent excitation devices is equal to the number of phases of the motor. Because each outer stator slot of four outer stator core teeth includes an excitation winding or a permanent magnet is embedded in the inner stator core radially corresponding to the outer stator slot, the number of outer stator core teeth sandwiched between the radial axes of two adjacent excitation devices is four. The motor is a four-phase, dual-stator, double-salient-pole motor.

[0012] The present invention improves the stator structure, designs the conventional single stator structure into a double stator structure, and places the permanent magnet on the inner stator, and places the excitation winding and the armature winding on the outer stator. On the one hand, the internal space utilization of the motor is effectively improved, thereby enhancing the torque output capacity of the motor; on the other hand, there is no direct contact between the permanent magnet and the armature winding. In addition, the heat generated by the AC armature winding during operation can be effectively dissipated by the motor casing; optionally, when the excitation device is only the permanent magnet arranged on the inner stator, the permanent magnet bearing The heat received is only caused by its own eddy current loss, and can be effectively discharged from the inner wall of the center of the inner stator, so the risk of thermal demagnetization is significantly reduced; optionally, when the excitation device is only an excitation winding arranged on the outer stator, the risk of thermal insulation loss of the copper wire can be reduced, and the weak magnetic speed regulation capability of the motor can be improved; optionally, when the excitation device is an excitation winding arranged on the outer stator and a permanent magnet arranged on the inner stator, that is, a mixed excitation of the magnetic source composed of permanent magnets and excitation windings, this can take into account both the torque output performance and the weak magnetic speed regulation performance of the motor.

[0013] Preferably, a heat sink is provided at the center of the inner stator to enhance the heat dissipation of the permanent magnets. The heat sink can be an air-cooled structure, a liquid-cooled structure, or a combination of the two. Specifically, the air-cooled structure can be a fan located at the end of the inner stator core, while the liquid-cooled structure can be a water-cooling channel axially opened in the center of the inner stator. The heat sink is used to enhance the heat dissipation capacity of the motor, allowing heat generated by the excitation device in the motor to be quickly dissipated through the inner stator core, thereby achieving a cooling effect.

[0014] Preferably, the rotor core blocks are arranged with skew poles, which can effectively suppress torque pulsation.

[0015] Preferably, the inner stator core is provided with radial inner stator core slots, each of which is secured with a crossbeam. Excitation windings are disposed within the inner stator core slots, and four outer stator core teeth separate the inner stator core slots from adjacent permanent magnets embedded in the inner stator core or the excitation windings disposed within the outer stator tooth slots. This arrangement ensures that the excitation windings within the inner stator core slots do not occupy space within the armature windings, resulting in a more rational layout. Furthermore, the excitation windings do not need to span multiple outer stator tooth slots, resulting in shorter end windings and physical isolation between the two windings, thereby reducing or even preventing heat accumulation between the two.

[0016] Preferably, the outer stator core yoke and the outer stator core teeth are integrally formed, thereby making the outer stator more solid and durable.

[0017] Preferably, the mechanical structure of the motor is in the form of rotation, linear or a combination of the two. The outer contour of the radial section of the outer stator core yoke is circular or polygonal.

[0018] Compared with the prior art, the beneficial effects of the present invention include at least:

[0019] In this invention, the stator is dual-core: an inner stator and an outer stator. Compared to existing single-stator solutions, the field winding and armature winding are placed on the outer stator, while the permanent magnets are placed on the inner stator. This effectively alleviates the spatial competition between them, effectively improving the motor's space utilization, which helps increase the electrical and magnetic load levels, and thus improve the motor's torque output capacity.

[0020] In the present invention, the permanent magnets and the armature coils are respectively placed on the inner and outer stators. Compared with the existing technical solutions (the permanent magnets are embedded in the yoke of the stator core and have to bear both their own eddy current loss heat and the heat conducted to the stator core by the windings), in the structure of the present invention, the excitation device and the armature windings avoid physical contact, effectively reducing the risk of thermal demagnetization of the permanent magnets.

[0021] In the present invention, the excitation device can adopt three excitation forms: permanent magnet excitation alone, excitation winding excitation alone, and "permanent magnet + excitation winding" mixed excitation. The excitation form is selected according to the application scenario requirements. Permanent magnet excitation alone can make the motor output a larger torque, excitation winding excitation alone can make the motor have good weak field speed regulation capability, and "permanent magnet + excitation winding" mixed excitation can make the motor take into account both torque output capability and weak field speed regulation capability.

[0022] In this invention, the armature windings are wound around the outer stator core teeth, fully utilizing the excellent thermal conductivity of the housing and improving heat dissipation. Embedding the permanent magnets in the inner stator core reduces losses and allows for rapid heat dissipation through a heat sink. Furthermore, the motor of this invention utilizes a skewed rotor pole design to suppress torque ripple.

Brief Description of the Drawings

[0023] Figure 1 This is a schematic diagram of the structure of a motor using permanent magnet excitation according to the present invention;

[0024] Figure 2 This is a schematic diagram of another motor structure using permanent magnet excitation according to the present invention;

[0025] Figure 3 This is a schematic diagram of another motor structure using permanent magnet excitation according to the present invention;

[0026] Figure 4 This is a schematic diagram of a motor structure using excitation winding excitation according to the present invention;

[0027] Figure 5 This is a schematic diagram of another motor structure using excitation winding excitation according to the present invention;

[0028] Figure 6This is a schematic diagram of the motor structure in which the excitation device of the present invention adopts hybrid excitation;

[0029] Figure 7 This is a schematic diagram of another motor structure in which the excitation device of the present invention adopts hybrid excitation;

[0030] Among them, 1-external stator, 11-external stator core yoke, 12-external stator core teeth, 13-armature winding, 14-external stator tooth slots, 15-excitation winding, 2-rotor, 21-rotor core block, 22-non-magnetic connection structure, 3-inner stator, 31-permanent magnet, 32-inner stator core, 33-inner stator core slots, 4-heat dissipation device. [Specific implementation method]

[0031] The present invention will be further described in detail below through specific embodiments in conjunction with the accompanying drawings, but the present invention is not limited to the following specific embodiments.

[0032] A four-phase double-stator double-salient-pole motor, such as Figures 1 to 6 As shown, it includes an outer stator 1, a rotor 2 and an inner stator 3 coaxially arranged from the outside to the inside, wherein the outer stator 1 includes an outer stator core yoke 11, outer stator core teeth 12 uniformly fixed on the inner side of the outer stator core yoke 11 in the circumferential direction, and an armature winding 13 wound on the outer stator core teeth 12, and an outer stator tooth slot 14 is opened between adjacent outer stator core teeth 12; the rotor 2 includes a plurality of arc-shaped rotor core blocks 21 and a non-magnetic connection structure 22 filled between two adjacent rotor core blocks 21. Specifically, the rotor 2 is composed of a rotor core block 21 and a non-magnetic connection structure 22 alternately combined, and the inner of the rotor core block 21 is provided with a plurality of arc-shaped rotor core blocks 21 and a non-magnetic connection structure 22 filled between two adjacent rotor core blocks 21. The diameter is equal to the inner diameter of the non-magnetic connection structure 22, and the outer diameter of the rotor core block 21 is equal to the outer diameter of the non-magnetic connection structure 22; the inner stator 3 includes an annular inner stator core 32; an excitation winding 15 is provided in the outer stator tooth slot 14 of every four outer stator core teeth 12, or a permanent magnet 31 is embedded in the inner stator core 32 radially corresponding to the outer stator tooth slot 14, and the polarities of adjacent excitation windings 15 are opposite, and the excitation windings 15 are connected in series with each other, wherein the excitation windings 15 and the permanent magnets 31 are both even numbers; the permanent magnets 31 and the excitation windings 15 are both excitation devices, and the number of the excitation devices N pm =2k, the number of teeth 12 of the outer stator core is N s =8k, the number of the rotor core blocks 21 is N r =6k or 10k, k is a positive integer, N r =10k, please refer to Figure 2 See further Figures 1 to 6As shown, the number of outer stator core teeth sandwiched by the radial axes of two adjacent excitation devices is the number of phases of the motor. Since an excitation winding 15 is provided in the outer stator tooth slot of each of the four outer stator core teeth or a permanent magnet 31 is embedded in the inner stator core radially corresponding to the outer stator tooth slot, the number of outer stator core teeth sandwiched by the radial axes of two adjacent excitation devices is 4, and the motor is a four-phase double-stator double-pole motor.

[0033] The present invention improves the stator structure, designs the conventional single stator structure into a double stator structure, and places the permanent magnet on the inner stator, and places the excitation winding and armature winding on the outer stator. On the one hand, the internal space utilization of the motor is effectively improved, thereby enhancing the torque output capacity of the motor; on the other hand, there is no direct contact between the permanent magnet and the armature winding; optionally, as Figure 1 、 Figure 2 and Figure 3 As shown, when the excitation device is only a permanent magnet arranged on the inner stator, the heat borne by the permanent magnet is only caused by its own eddy current loss, and can be effectively conducted away from the inner wall of the inner stator center, so the risk of thermal demagnetization is significantly reduced; Optionally, as Figure 4 、 Figure 5 As shown, when the excitation device is only the excitation winding arranged on the outer stator, the risk of thermal insulation loss of the copper wire can be reduced and the weak magnetic speed regulation capability of the motor can be improved; alternatively, as Figure 6 As shown, when the excitation device is an excitation winding arranged on the outer stator and a permanent magnet arranged on the inner stator, that is, a hybrid excitation of the magnetic source composed of the permanent magnet and the excitation winding is formed, this can take into account both the torque output performance and the weak magnetic speed regulation performance of the motor.

[0034] Furthermore, in this embodiment, a heat dissipation device 4 is provided at the center of the inner stator 3 .

[0035] Furthermore, in this embodiment, the rotor core blocks 21 are arranged with skew poles.

[0036] Further, refer to Figure 7 As shown, in this embodiment, radial inner stator core slots 33 are defined in the inner stator core 32. A crossbeam is secured within each inner stator core slot 33. Excitation windings 15 are disposed within each inner stator core slot 33. Four outer stator core teeth 12 separate the inner stator core slot 33 from the adjacent permanent magnets 31 embedded in the inner stator core 32 or the excitation windings 15 disposed within the outer stator slots 14. This arrangement ensures that the excitation windings 15 within the inner stator core slots 33 do not occupy space within the armature windings 13, resulting in a more rational layout. Furthermore, the excitation windings 15 do not need to span multiple outer stator slots 14, resulting in shorter end windings. Furthermore, the two windings are physically isolated, thus preventing heat buildup.

[0037] Furthermore, in this embodiment, the mechanical structure of the motor is in the form of rotation, linear or a combination of the two.

[0038] Furthermore, in this embodiment, the outer stator core yoke 11 and the outer stator core teeth 12 are integrally formed.

[0039] Furthermore, in this embodiment, the outer contour of the radial section of the outer stator core yoke 11 is circular or polygonal.

[0040] The above is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art who is familiar with the technical field can easily think of changes or replacements within the technical scope disclosed by the present invention, which should be included in the scope of protection of the present invention. In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention. Therefore, the scope of protection of the present invention shall be based on the scope of protection of the claims.

Claims

1. A four-phase double-stator double-salient-pole motor, comprising an outer stator (1), a rotor (2) and an inner stator (3) coaxially arranged in sequence from the outside to the inside, characterized in that: The outer stator (1) comprises an outer stator iron core yoke (11), outer stator iron core teeth (12) uniformly fixed circumferentially on the inner side of the outer stator iron core yoke (11), and an armature winding (13) wound on the outer stator iron core teeth (12), and outer stator tooth slots (14) are provided between adjacent outer stator iron core teeth (12); The rotor (2) comprises a plurality of arc-shaped rotor core blocks (21) and a non-magnetic connection structure (22) filled between two adjacent rotor core blocks (21); The inner stator (3) includes an annular inner stator core (32); An excitation winding (15) is provided in the outer stator tooth slot (14) of every four outer stator core teeth (12), or a permanent magnet (31) is embedded in the inner stator core (32) radially corresponding to the outer stator tooth slot (14), and the polarities of adjacent excitation windings (15) are opposite, and the excitation windings (15) are connected in series with each other, wherein the number of excitation windings (15) and permanent magnets (31) are both even; the permanent magnets (31) and excitation windings (15) are both excitation devices, and the number of the excitation devices is N. pm =2k, the number of the outer stator core teeth (12) is N s =8k, the number of the rotor core blocks (21) is N r =6k or 10k, where k is a positive integer.

2. The four-phase double-stator double-salient-pole motor according to claim 1, characterized in that: A heat dissipation device (4) is provided at the center of the inner stator (3).

3. The four-phase double-stator double-salient-pole motor according to claim 1, characterized in that: The rotor core block (21) adopts an oblique pole arrangement.

4. The four-phase double-stator double-salient-pole motor according to claim 1, 2 or 3, characterized in that: A plurality of inner stator core slots (33) are radially provided on the inner stator core (32), and excitation windings (15) are provided in the inner stator core slots (33).

5. The four-phase double-stator double-salient-pole motor according to claim 1, characterized in that: The mechanical structure of the motor is in the form of rotation, linear or a combination of the two.

6. The four-phase double-stator double-salient-pole motor according to claim 1, characterized in that: The outer stator core yoke (11) and the outer stator core teeth (12) are integrally formed.

7. The four-phase double-stator double-salient-pole motor according to claim 1, characterized in that: The outer contour of the radial section of the outer stator core yoke (11) is circular or polygonal.

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