Stator assembly, generator and wind generating set

Abstract

The invention provides a stator assembly, a generator and a wind generating set. The stator assembly comprises a stator core, a multi-turn winding and an inter-turn insulating layer arranged on the periphery of each turn of winding, a stator groove is formed in the stator core, the windings are arranged in the stator grooves, each turn of winding is formed by winding a plurality of strands of conductors in parallel, the conductors are flat aluminum conductors with rectangular sections, and in the same stator groove, the cross section of each flat aluminum conductor is rectangular. The cross sectional area of the first turn of winding close to the notch is larger than that of the other turns of windings, the number of layers of the conductors in the first turn of winding is larger than that of the conductors in the other turns, and the thickness of the conductors in the first turn of winding is smaller than that of the conductors in the other turns of windings. According to the scheme of the invention, the manufacturing cost of the generator can be reduced while the performance of the generator is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of wind power generation, and particularly relates to a stator assembly, a generator, and a wind turbine generator set. Background Art

[0002] With the increasing requirements for the environment, wind power generation technology as a clean energy source has received more and more attention. As an important part of a wind turbine generator set that converts wind energy into electrical energy, the manufacturing cost and performance of the generator have a crucial impact on the operating cost and efficiency of the wind turbine generator set. In order to reduce the internal resistance of the generator, reduce heat generation, and improve the efficiency of the generator, the stator assembly of the generator in the prior art usually adopts a copper wire winding. However, the price of copper wire is relatively high, which is the main factor affecting the cost of the generator.

[0003] In order to reduce the manufacturing cost of the generator, a scheme of replacing copper wire with aluminum wire has been proposed in the prior art. In the case of replacing copper wire with aluminum wire, according to the purpose of reducing the manufacturing cost, it is not desired to increase the outer diameter size of the motor, and at the same time, it is also necessary to adapt to the existing installation space. However, if the outer diameter size of the stator remains unchanged and the same or similar power is obtained, due to the relatively large resistance value of the aluminum wire, the heat generation of the generator will increase significantly, resulting in serious heat generation of the winding, damaging the insulation structure, affecting the safety performance of the generator, and at the same time reducing the operating efficiency of the generator.

[0004] Therefore, how to control the temperature of the generator while using aluminum wire to replace copper wire to reduce the cost of the generator is a difficult problem faced by those skilled in the art. Summary of the Invention

[0005] The purpose of the present invention is to provide a stator assembly, a motor, and a wind turbine generator set including the motor stator assembly, and adjust the distribution of coil heat generation through the design of the generator slot structure and the combination design of aluminum coils to adapt to the ventilation structure of the motor in the prior art, so as to reduce the temperature of the generator while reducing the cost of the generator.

[0006] According to an aspect of the present invention, a stator assembly is provided. The stator assembly includes a stator core, a multi-turn winding, and an inter-turn insulation layer provided on the outer periphery of each turn of the winding. A stator slot is formed in the stator core, and the winding is disposed in the stator slot. The feature is that each turn of the winding is formed by multiple strands of conductors wound together. The conductor is a rectangular cross-section aluminum conductor. In the same stator slot, the cross-sectional area of the first turn of the winding near the slot opening is larger than that of other turns of the winding. The number of layers of the conductors in the first turn of the winding is greater than that of the conductors in other turns, and the thickness of the conductors in the first turn of the winding is less than the thickness of the conductors in other turns of the winding.

[0007] According to one aspect of the present invention, the stator slots are parallel slots. In the same stator slot, along the direction from the slot opening to the slot bottom, the cross-sectional area of each turn of the winding gradually decreases, and the number of conductor layers of each turn of the winding gradually decreases.

[0008] According to one aspect of the present invention, in the same stator slot, from the second turn of the winding to the N / 2th turn of the winding, the cross-sectional area of each turn of the winding gradually decreases, the number of layers of each turn of the winding is the same, the thickness of the conductors connected in parallel for each turn gradually decreases from the second turn of the winding to the N / 2th turn of the winding, from the N / 2th turn of the winding to the Nth turn of the winding, the cross-sectional area of the winding is the same, and is smaller than the cross-sectional area of the first turn of the winding to the N / 2th turn of the winding, and the thickness of the conductors connected in parallel in the corresponding each turn of the winding gradually increases, and is greater than the thickness of the conductors connected in parallel in the first turn of the winding to the N / 2th turn of the winding.

[0009] According to one aspect of the present invention, the range of the slot height hs0 of the stator slot is 5 mm ≤ hs0 ≤ 12 mm, and the slot height hs0 and the slot depth hs2 of the stator slot satisfy the following relationship:

[0010]

[0011] According to one aspect of the present invention, an inter-turn insulation layer is provided between the multiple strands of conductors in each turn of the winding, and the range of the thickness h of the inter-turn insulation layer is 0 ≤ h ≤ 0.2 mm.

[0012] According to one aspect of the present invention, the stator core is cylindrical, the opening of the stator slot faces the radial inner side of the stator core, and the outer diameter D of the stator core is greater than 1900 mm and less than 2800 mm.

[0013] According to one aspect of the present invention, the stator slot is a parallel opening slot, the cross-sectional shape of each turn of the winding is rectangular, and each turn of the winding is formed by stacking multiple strands of wires in the radial direction or in the circumferential direction of the stator core.

[0014] According to another aspect of the present invention, a generator is provided, and the generator includes the stator assembly described above.

[0015] According to another aspect of the present invention, the generator includes a motor housing, a stator assembly, and a rotor assembly. The stator assembly is disposed inside the motor housing, the rotor assembly is disposed inside the stator assembly, an air inlet and an air outlet are provided on the motor housing, the air inlet is located at both axial ends of the stator assembly, the air outlet is located in the middle of the stator assembly, an air gap is formed between the stator assembly and the rotor assembly, the air gap communicates with the slot opening, and an axial ventilation duct is jointly formed. The stator assembly is further provided with a radial ventilation duct, and the radial ventilation duct communicates the axial ventilation duct with the air outlet.

[0016] According to another aspect of the present invention, the generator is a semi-direct drive permanent magnet wind generator, and the frequency range of the motor is 90 Hz to 120 Hz.

[0017] According to another aspect of the present invention, the generator has a ground insulation structure and a conductor insulation structure, and the insulation grades of the ground insulation structure and the conductor insulation structure are H grade.

[0018] According to still another aspect of the present invention, there is provided a wind power generating set, and the wind power generating set includes the generator described above.

[0019] According to still another aspect of the present invention, the wind generator is a semi-direct drive permanent magnet generator. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Through the following detailed description of exemplary embodiments in conjunction with the drawings, the above and other aspects, features and advantages of the present invention will become clear and more easily understood. In the drawings:

[0021] Figure 1 is a schematic diagram of a stator lamination according to an embodiment of the present invention;

[0022] Figure 2 is a partial structural schematic diagram of one of the stator assemblies of a stator assembly according to an embodiment of the present invention;

[0023] Figure 3 is a schematic diagram of a winding structure in one of the stator slots of a stator assembly according to an embodiment of the invention;

[0024] Figure 4 is a schematic diagram of the cross-sectional area change of a multi-turn winding arranged in one of the winding slots according to an embodiment of the present invention;

[0025] Figure 5 is a schematic diagram of the thickness and number of layers change of each conductor in each turn of winding arranged in one of the winding slots according to an embodiment of the present invention;

[0026] Figure 6 is a schematic diagram of the structure of a generator according to an embodiment of the present invention;

[0027] Figure 7 is a schematic diagram for comparing the axial temperature distribution of a generator according to an embodiment of the present invention with the axial temperature distribution of a generator in the prior art;

[0028] Figure 8 is a schematic diagram for comparing the manufacturing cost of a generator according to an embodiment of the present invention with the manufacturing cost of a generator in the prior art;

[0029] Figure 9 is a temperature distribution diagram of a copper wire winding motor in the prior art;

[0030] Figure 10 is the temperature distribution diagram of the aluminum wire-wound motor according to the present invention. Detailed implementation manners

[0031] In order to enable those skilled in the art to better understand the technical concept of the present invention, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In the drawings, the same reference numerals always denote the same or similar elements.

[0032] It will be understood that although terms such as "first", "second", etc. may be used herein to describe various elements, these elements will not be limited by these terms. Rather, these terms are only used to distinguish one element from another. Thus, the first element referred to in the exemplary embodiments described herein may also be referred to as the second element without departing from the teachings of the exemplary embodiments.

[0033] For ease of description, the "inner", "outer", "upper", and "lower" referred to hereinafter are consistent with the inner, outer, upper, and lower directions of the drawings themselves, but do not limit the structure of the present invention.

[0034] In addition, throughout the specification, when an element is described as being "disposed on", "connected to", or "coupled to" another element, the element may be directly "disposed on", directly "connected to", or directly "coupled to" the other element, or there may be one or more other elements therebetween.

[0035] The present invention aims to provide a stator assembly, a generator including the stator assembly, and a wind power generation set. In an embodiment of the present invention, by replacing a copper wire winding with an aluminum wire winding, the manufacturing cost of the generator is reduced, and the operating temperature of the generator is effectively controlled.

[0036] In the case of replacing copper wire with aluminum wire, it is necessary to ensure that the power of the generator is the same or similar. In order to adapt to the existing generator assembly space, the outer diameter of the stator of the generator is the same or has a small difference. Since the resistance of aluminum wire is 1.64 times that of copper wire, if aluminum wire is directly used to replace copper wire, it means that under the same product power, the heat generation of the generator will increase significantly, resulting in serious heating of the winding and damage to the insulation structure. Therefore, the wire gauge of the aluminum wire needs to be increased to reduce the resistance of the aluminum wire. However, at the same time, the required slot space will also increase. In order to increase the slot space, it can be achieved by increasing the slot width or slot depth. However, increasing the slot width dimension will increase the tooth magnetic density and even cause saturation, and the iron loss will also increase. Therefore, the present invention preferentially considers increasing the slot depth.

[0037] Increasing the slot depth can be achieved by thinning the stator yoke size or reducing the stator inner diameter size. However, when the stator outer diameter size remains unchanged, if the stator yoke is thinned, the structural strength will be reduced, the magnetic density of the yoke will increase, and the iron loss will also rise accordingly. Therefore, the present invention finally determines to increase the slot space by reducing the stator inner diameter.

[0038] If, according to the solution of the prior art, aluminum wire replacing copper wire is embedded in the stator slots, the inner diameter of the stator needs to be reduced more, resulting in an increase in the stator tooth length, a reduction in the tooth strength, and an increase in the amount of stator punching sheets, leading to an increase in the weight and cost of the generator. On the other hand, due to the increase in the total thickness of the aluminum wire embedded in the stator slots, affected by the skin effect, the eddy current loss of its conductor will also increase, resulting in an increase in the winding temperature. Therefore, the depth of the stator slots should not be increased excessively.

[0039] Based on considering the above-mentioned various factors, an embodiment of the present invention provides a stator assembly. Next, it will be described in detail with reference to Figure 1 and Figure 2 the stator assembly according to the embodiment of the present invention.

[0040] According to an embodiment of the present invention, the stator assembly includes a stator core 100, a winding 200, and a slot wedge 300. The stator core 100 is a laminated structure formed by laminating a plurality of stator laminations together. Figure 1 A schematic diagram of one of the stator laminations is shown. A plurality of tooth portions 110 are formed on the stator core 100 along the circumferential direction, and stator slots 120 are formed between the plurality of tooth portions 110. The stator slots 120 extend along the radial direction of the stator core, one end is a closed slot bottom, and the other end is an open slot mouth, and the winding 200 is embedded in the stator slots 120 through the slot mouth.

[0041] Figure 2 is a schematic diagram of one of the stator slots and the winding structure of the stator assembly according to the embodiment of the present invention. As Figure 2 shown, in the depth direction of the stator slot 120, multiple turns of the winding 200 are stacked in the stator slot 120. A slot wedge insertion slot is also formed at the open end of the stator slot 120, and the slot wedge 300 can be inserted into the slot wedge insertion slot to limit the winding 200 in the stator slot 120 and prevent the winding 200 from falling out of the stator slot 120.

[0042] According to an embodiment of the present invention, the stator core 100 is formed in a cylindrical shape, the opening of the stator slot 120 faces the radial inner side of the stator core 100, and the rotor can be installed inside the stator assembly to form an inner rotor outer stator generator. However, the embodiment of the present invention is not limited thereto, and the opening of the stator slot 120 can also face the radial outer side, thereby forming an inner stator outer rotor generator.

[0043] In an embodiment of the present invention, the winding 200 is made of aluminum wire to reduce the manufacturing cost and weight of the generator. The stator slots are formed as parallel slots, that is, the stator slots 120 have sides extending in parallel, and in the depth direction of the stator slots 120, the width of the stator slots 120 is consistent, which facilitates embedding the winding 200 in the stator slots 120. In each stator slot 120, multiple turns of the winding 200 are provided, and each turn of the winding 200 is formed in a rectangular shape.

[0044] In an embodiment of the present invention, an aluminum wire conductor with a flat rectangular cross-section is adopted. Each turn of the winding 200 is formed by multiple strands of aluminum wire conductors wound side by side, and the cross-sectional shape is rectangular. The multiple strands of aluminum wire conductors can be stacked in the radial direction of the stator core 100 or stacked in the circumferential direction of the stator core 100. By using flat aluminum wires stacked and wound to form each turn of the winding 200 and having a rectangular cross-section, on the one hand, the slot fill factor can be improved, which is beneficial to reducing the depth of the stator slots 120; on the other hand, the contact area between the conductors is relatively large, so that the heat conduction ability between the conductors and between the winding 200 and the stator core 100 can be improved, which is beneficial to heat dissipation and reducing the temperature of the generator.

[0045] During the high-speed operation of the generator, due to the high-frequency change of the magnetic field, the skin effect will occur in the current flowing through the winding, resulting in an increase in the effective resistance of the conductor, an increase in eddy current loss, an increase in the temperature of the generator, and an impact on the output power and operating performance of the generator. Since the slot opening of the stator slot 120 is closer to the rotor than the bottom of the stator slot 120, during the high-speed operation of the generator, the skin effect of the winding 200 near the slot opening is more obvious.

[0046] According to an embodiment of the present invention, since the eddy current loss caused by the skin effect is mainly located near the slot opening, in order to reduce the eddy current loss caused by the skin effect, for the stator assembly according to the embodiment of the present invention, compared with the prior art, the slot opening height is increased.

[0047] As Figure 2 shown, in the radial direction of the stator core, the slot opening height of the stator slot is hs0, the slot wedge height is hs1, and the slot height is hs2.

[0048] On the one hand, according to an embodiment of the present invention, compared with the stator assembly in the prior art, the slot opening height hs0 of the stator slot is increased, which increases the distance between the winding 200 and the slot opening, and thus increases the distance from the rotor, reducing the influence of the alternating magnetic field on the winding 200 during the high-speed operation of the generator. In particular, it reduces the influence on the first turn of the winding near the slot opening, thereby reducing the eddy current loss of the entire generator and reducing the heat generation of the generator.

[0049] In the radial direction of the stator core, there is an air gap between the stator assembly and the rotor assembly, and this air gap can be used as an axial ventilation duct for introducing cold air to cool the generator. According to another aspect of the embodiments of the present invention, the notch communicates with the air gap between the stator assembly and the rotor assembly. Since the notch size increases, the cross-section of the axial ventilation duct is enlarged, the wind resistance is reduced, and the ventilation volume is increased, thereby improving the cooling effect of the generator.

[0050] During the design process of the motor, the greater the height of the notch, the higher the leakage reactance of the motor and the more power loss. Therefore, those skilled in the art generally design the notch height to be smaller to reduce the leakage reactance of the motor and avoid power loss of the motor.

[0051] However, the inventors of the present invention have found through research and verification that although the power can increase when the notch size is designed to be smaller, the eddy current loss will also increase at the same time, and the proportion of the increase in eddy current loss is more than the proportion of the increase in power. After the notch size is increased to exceed a certain size, the eddy current loss near the notch decreases significantly, making the reduction of eddy current loss significantly higher than the power reduction caused by leakage reactance. In addition, since the height hs0 of the notch increases, the cross-sectional area of the axial ventilation duct between the stator assembly and the rotor assembly increases, and the ventilation and cooling effect is further enhanced. Therefore, compared with the increase in power, better effects can be achieved from the perspectives of reducing the temperature rise of the generator and reducing losses. By reducing the eddy current loss, it is beneficial to reduce the amount of aluminum wire winding and shorten the length of the stator teeth.

[0052] According to the embodiments of the present invention, the value range of the height hs0 of the notch of the stator slot 120 is 5 mm ≤ hs0 ≤ 12 mm. For example, the values can be 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, etc. If the notch height dimension hs0 is less than 5 mm, the effect of reducing eddy current loss is not obvious. If hs0 is greater than 12 mm, it will affect the size of the stator assembly or the effective cross-sectional area of the stator slot 120. Specifically, in order to ensure that the outer diameter dimension of the stator assembly does not increase and to ensure the strength of the stator core without reducing the thickness of the stator core yoke, if hs0 is greater than 12 mm and the depth direction dimension of the stator slot remains unchanged, the effective cross-section in the stator slot will be reduced, and the cross-sectional area of the winding will be reduced, resulting in a decrease in the power of the generator. If the design requirements are met by increasing the size of the slot depth hs2, it means that the yoke of the stator core will become thinner, the magnetic density will increase, the iron loss will increase, the efficiency will decrease, and at the same time, the mechanical strength of the stator will be reduced. If the outer diameter of the stator core is increased to ensure the thickness of the stator core yoke, the size and weight of the generator will increase, the materials used will increase, and the cost will rise. Therefore, the notch height dimension and the slot depth need to be limited within an appropriate range.

[0053] For the stator assembly according to an embodiment of the present invention, in order to ensure the effective cross-sectional area of the stator slots, avoid an increase in iron loss, and ensure the mechanical strength of the stator, the slot height hs0 and the slot depth hs2 of the stator slot 120 satisfy the following relationship:

[0054]

[0055] Through the above formula (1), the slot depth hs2 of the stator slot is limited within a certain range.

[0056] As Figure 3 shown, according to an embodiment of the present invention, N turns of windings are arranged in the stator slot 120 in sequence from the slot opening of the stator slot 120 towards the slot bottom of the stator slot 130. The larger the cross-sectional area of a single conductor in the winding, the greater the eddy current loss. Therefore, in the present invention, each turn of the winding is constructed by parallelly winding multiple conductors, so that the cross-sectional area of a single conductor is reduced, the skin effect can be reduced, the equivalent resistance can be reduced, and thus the eddy current loss can be reduced.

[0057] Compared with the solution of making windings with single rectangular cross-section conductors in the prior art, according to an embodiment of the present invention, by designing each turn of the winding to be composed of multiple layers of flat aluminum wires wound and stacked in parallel, compared with each winding being composed of a single aluminum wire, the skin effect can be significantly reduced, thereby reducing the eddy current loss caused by the skin effect, improving the current-carrying capacity of each turn of the winding, reducing the cross-sectional area of each turn of the winding, and further reducing the amount of aluminum used.

[0058] According to an embodiment of the present invention, in the same stator slot, the cross-sectional area of the first turn of the winding near the slot opening is the largest, which can reduce the DC resistance of the winding at the slot opening and reduce the DC loss. In the direction towards the slot bottom, since the heat dissipation capacity of the winding gradually increases and the current-carrying capacity of a single turn of the winding increases, therefore, in the case of passing the same current, the cross-sectional area of each turn of the winding gradually decreases, thereby being able to save the amount of aluminum used and also reducing the slot depth dimension. According to an embodiment of the present invention, the stator slot 120 is a parallel slot, so the width of each turn of the winding is the same, and thus each turn of the winding has a tendency of gradually decreasing thickness in the radial direction of the stator assembly.

[0059] As an example, from the second turn of the winding to the N / 2th turn of the winding, the cross-section of each turn of the winding decreases relative to the cross-sectional area of the first turn of the winding. From the N / 2th turn of the winding to the Nth turn of the winding, since both the DC loss and the eddy current loss decrease, the thickness of the winding can be the same or gradually decrease, and both are smaller than the cross-sectional area of the first turn of the winding to the N / 2th turn of the winding.

[0060] The eddy current loss caused by the skin effect is mainly located near the slot opening. Therefore, according to an embodiment of the present invention, in the same stator slot, the number of conductor layers in the first turn of the winding near the slot opening is the largest, greater than that in other turns of the winding, and the cross-sectional area of each aluminum wire conductor is smaller than that of each aluminum wire conductor in other turns of the winding in the same stator slot, that is, the thickness of the aluminum wire conductor in the winding near the slot opening is the smallest.

[0061] In addition, in the direction towards the slot bottom, the influence of the skin effect gradually decreases. Therefore, the number of layers of each turn of the winding can be reduced, and the thickness of each layer of aluminum wire can be increased, so that the number of conductor layers in the first turn of the winding near the slot opening is more than that in other turns of the winding in the same stator slot. In the direction towards the slot bottom, the number of layers of each turn of the winding gradually decreases, reducing the amount of aluminum used and also reducing the slot depth dimension. In addition, since the number of parallel strands is reduced, it is beneficial to the manufacturing process.

[0062] Considering that the skin effect mainly occurs in the middle of the depth of the stator slot near the rotor side, according to an embodiment of the present invention, from the second turn of the winding to the N / 2th turn of the winding, the number of aluminum wire conductor layers in each turn of the winding gradually decreases, and relative to the first turn, the thickness of the aluminum wire conductor increases. From the N / 2th turn to the Nth turn of the winding, the number of aluminum wire conductor layers in each turn of the winding can be the same or gradually decrease, while the thickness of the aluminum wire conductor gradually increases. In the direction towards the slot bottom, by increasing the thickness of the aluminum wire, the number of parallel aluminum wires in a single turn of the winding is reduced, which is beneficial to the manufacturing process.

[0063] Figure 4 The schematic diagram of the winding thickness change in one of the stator slots according to an embodiment of the present invention is shown. In this example, 10 turns of windings are arranged in each stator slot, and the thickness L of each turn of the winding in the radial direction of the stator assembly can be set according to Table 1 below.

[0064] Table 1

[0065]

[0066] From the first turn of the winding to the fifth turn of the winding, the thickness of each turn of the winding gradually decreases, so that the cross-section gradually decreases. From the fifth turn to the tenth turn of the winding, the thickness of each turn of the winding is the same and is smaller than the thickness of the first turn of the winding to the fifth turn of the winding.

[0067] According to the maximum allowable temperature of the generator, the calorific value allowed for each turn of the winding is determined, thereby determining the cross-sectional area of each turn of the winding and the number of layers of the parallel conductors. In this case, the cross-sectional area of each turn of the winding can be minimized, thereby reducing the depth of the stator slot. In addition, according to an embodiment of the present invention, from the first turn of the winding near the slot opening to the Nth turn of the winding near the slot bottom, the number of conductors n stacked in each turn of the winding gradually decreases, but it is not strictly required to decrease turn by turn, and can be determined according to the allowed calorific value, the cross-sectional area of each turn of the winding, and the cross-sectional area between adjacent windings. For example, in Figure 5 Among them, the number of stacked layers n of the aluminum wire in the first turn of the winding is 5, and the number of stacked layers n of the aluminum wire in the second turn to the fifth turn of the winding is 4. For the fifth turn of the winding to the tenth turn of the winding, the number of layers n can be the same or gradually decrease. For example, for the sixth turn to the eighth turn of the winding, the number of layers n is all 3, and for the ninth turn and the tenth turn of the winding, the number of conductors n in each turn is 2.

[0068] According to one aspect of the embodiment of the present invention, the cross-sectional area of the first turn of the winding is the largest, the number of conductor layers is the largest, and the thickness of the conductors in the first turn of the winding is the smallest. In the direction towards the slot bottom, the cross-sectional area of each turn of the winding gradually decreases, and the number of layers also has a tendency to gradually decrease. When the temperature permits, the thickness of the conductors in the winding can be increased, which is beneficial to reducing the thickness of each turn of the winding, saving the space in the slot, and facilitating the manufacturing process.

[0069] As an example, from the second turn of the winding to the N / 2th turn of the winding, the thickness of the parallel conductors in each turn can gradually decrease, and all are greater than the thickness of the conductors in the first turn of the winding; from the N / 2th turn of the winding to the Nth turn of the winding, the thickness of the parallel conductors in the corresponding turns of the winding gradually increases, and all are greater than the thickness of the conductors in the first turn to the N / 2th turn of the winding.

[0070] Figure 5 Fig. shows a schematic diagram of the number of layers and thickness settings of the winding in one of the stator slots according to an embodiment of the present invention. In this example, 10 turns of windings are arranged in each stator slot, and the thickness t of the conductors in each turn of the winding can be set according to Table 2 below.

[0071] Table 2

[0072]

[0073] According to the embodiment of the present invention, by simultaneously increasing the cross-sectional area of the first turn of the winding and increasing the number of parallel conductors, and reducing the thickness of each conductor, the effects of reducing both DC losses and AC losses can be obtained simultaneously, so that the total losses of the first turn of the winding at the slot opening decrease. By reducing the DC losses and eddy current losses, the temperature of the winding is reduced, so that the equivalent resistance of the winding is reduced. When the same magnitude of current flows through, the required cross-sectional area of the winding is reduced, thereby saving the amount of aluminum used.

[0074] According to another aspect of the present invention, while increasing the notch height hs0, using multiple conductors wound side by side to form each turn of the winding 200 so as to reduce eddy current loss and improve the cooling effect, the insulation structure in the stator slot is also adjusted to jointly achieve the technical effect of reducing the slot depth. According to an embodiment of the present invention, each turn of the winding 200 is formed by winding multiple conductors side by side. The conductors can be bare wires, and no insulation layer is provided between each strand of conductors. That is, compared with the prior art, the inter-strand insulation layer is cancelled, thereby avoiding excessive occupation of the stator slot space by the insulation material and improving the slot fill factor. In addition, by cancelling the inter-strand insulation layer, there are more parallel winding numbers of conductors in each turn of the winding, solving the problem that the current density of aluminum wire is too large due to high resistance, resulting in conductor heating.

[0075] In addition, a layer of paint film, such as polyimide film, can also be coated on the surface of the wire to further reduce the skin effect. According to yet another aspect of the present invention, an inter-strand insulation layer can also be provided, but the thickness h of the inter-strand insulation layer is less than 0.2 mm to reduce the usage amount of the inter-strand insulation. On the one hand, it saves the slot space and reduces the depth of the slot. On the other hand, reducing the usage amount of the insulation material will also reduce the cost of the generator.

[0076] According to an embodiment of the present invention, when the notch height is increased, in order to avoid excessive increase in the slot depth, resulting in an increase in the stator size and cost, the thickness of the inter-strand insulation layer is thinned or the inter-strand insulation layer is not provided, so that the overall height of the winding in the slot decreases, avoiding an increase in the stator outer diameter caused by the increase in the slot depth, thereby reducing the cost of the generator. According to one aspect of the embodiment, the insulation grades of the ground insulation and the conductor insulation of the stator assembly are H grade.

[0077] In the prior art, it is generally considered that an inter-strand insulation layer needs to be provided between the parallel windings. However, through research and verification, the present invention finds that since the current directions are the same between the multiple parallel windings, even if no inter-strand insulation layer is provided or the thickness of the inter-strand insulation layer is thinned between the conductors, there is no risk of breakdown of the motor insulation layer, reducing the usage amount of the insulation material and lowering the manufacturing cost.

[0078] According to an embodiment of the present invention, flat aluminum wire conductors are stacked and wound side by side to form a single-turn winding. An inter-turn insulation layer is wrapped around the outer periphery of each turn of the winding to insulate adjacent turns of the winding from each other. The cross-section of each turn of the winding is rectangular to improve the utilization rate of the slot space of the stator slot.

[0079] According to one aspect of the embodiment, the stator slots 120 are skewed slots, that is, in the axial direction of the stator assembly, the stator slots are inclined at a certain angle with respect to the axis direction of the stator assembly. By adopting skewed slots, the air gap between the winding 200 and the stator core 100 can be reduced, thereby reducing the leakage magnetic loss and the vibration noise of the core. In addition, the skewed slots can also improve the heat dissipation effect of the generator, effectively control the temperature rise of the generator, and thus improve the reliability and service life of the motor.

[0080] According to an embodiment of the present invention, a wind turbine generator is provided, and the generator includes the above-mentioned stator assembly. Further, the wind turbine generator is a semi-direct drive wind turbine generator, whose frequency range is 90Hz to 120Hz, the outer diameter D of the stator core is greater than 1900mm and less than 2800mm.

[0081] The higher the frequency range, the greater the AC loss, and thus the temperature of the motor rises. In order to control the temperature of the generator, on the one hand, from the perspective of reducing the motor loss and thus reducing the heat generation, the slot opening height is increased and the cross-sectional area of each turn of the winding, the number of conductors in each turn of the winding, and the thickness are adjusted, thereby reducing the heat generation. In addition, according to another aspect of the present invention, from the perspective of strengthening heat dissipation and ventilation by using the increased slot opening height to avoid the temperature rise of the generator, the required amount of aluminum is reduced, and the purpose of cost reduction is achieved while ensuring the performance of the motor.

[0082] As Figure 6 shown, according to another aspect of the embodiment, a generator 400 is provided. The generator 400 includes a motor housing 410, a stator assembly disposed in the motor housing, and a rotor disposed in the stator assembly. An air inlet 411 and an air outlet 412 are further provided on the motor housing 410. The air inlet 411 is located at both ends of the stator assembly, and the air outlet 412 is provided in the middle of the motor housing 410. An air gap is formed between the stator assembly and the rotor assembly, and the air gap communicates with the slot opening of the stator slot to jointly form an axial ventilation duct. The stator assembly is further provided with a radial ventilation duct, and the radial ventilation duct communicates the axial ventilation duct with the air outlet 412. Cold air is introduced from both ends of the stator assembly, after cooling the end windings, it enters the axial ventilation duct between the stator assembly and the rotor assembly, and then passes through the radial ventilation duct of the stator assembly and is discharged outward from the air outlet 412.

[0083] Under the above structural arrangement where the slot opening height is increased, and the cross-sectional area of the winding near the slot opening is the largest, the number of parallel conductors is the largest, and the conductor thickness is the smallest, the heat generation of the end of the aluminum wire winding is greater than that of the middle. Figure 9 is the temperature distribution diagram of the copper wire winding motor in the prior art; Figure 10It is the temperature distribution diagram of the aluminum wire-wound motor according to the present invention. It can be seen that in the above generator, the cooling ventilation structure with air intake from both ends and air outlet in the middle of the generator better matches the distribution characteristics of the heat generated by the aluminum wire motor, the cooling effect of the whole machine is better, and the overall temperature distribution is lower than that of the copper wire-wound motor.

[0084] According to the embodiment of the present invention, since the slot opening height hs0 of the stator slot 120 is increased, the ventilation and cooling effect is greatly improved. At the same time, since the inter-strand insulation layer between each turn of the winding is thinned or there is no inter-strand insulation layer, the heat conduction performance of the winding itself is increased, and heat is more easily conducted from the winding to the stator core and taken away by the cold air.

[0085] According to the embodiment of the present invention, through the design of the winding insulation structure and the slot opening height, the utilization rate of the stator slot space can be increased and the AC loss of the winding can be reduced, so as to reduce the influence caused by the relatively large resistivity of the aluminum wire winding, significantly reduce the temperature rise and manufacturing cost of the generator, and enable the implementation of the scheme of replacing copper wire with aluminum wire.

[0086] Figure 7 It is a schematic diagram comparing the axial temperature distribution of the generator according to the embodiment of the present invention with the axial temperature distribution of the generator in the prior art.

[0087] Through Figure 7 the comparison of the temperature distributions therein, it can be seen that in the axial direction of the generator, when the temperature of the end winding is the same, the internal temperature of the generator of the present invention is significantly reduced and is less than the internal temperature of the generator with copper wire windings.

[0088] According to the conventional design method, when aluminum wire replaces copper wire, with the same DC resistance, the cross-sectional area of the aluminum wire winding will be about 1.64 times that of the copper winding. According to the solution of the embodiment of the present invention, due to the reduction of the AC resistance and the reduction of the eddy current loss, and the increase of the slot opening height to improve heat dissipation, the cross-sectional area of the aluminum wire winding used is about 1.33 times that of the copper wire winding. Therefore, compared with the conventional scheme of replacing copper wire winding with aluminum wire winding, the amount of aluminum wire used is greatly reduced, the excessive increase of the depth of the stator slot is avoided, the performance of the generator is ensured, and at the same time, the manufacturing cost of the generator is reduced.

[0089] The generator according to the present invention can significantly reduce the manufacturing cost of the generator compared with the generator using copper wire windings. As Figure 8 shown, when the power is the same, compared with the generator using copper wire windings, the manufacturing cost of the generator using aluminum wire windings in the embodiment of the present invention can be reduced by about 22.5%.

[0090] Although specific examples of the present invention have been described with reference to the accompanying drawings, the solutions of the present invention are not limited thereto. Without departing from the spirit and scope of the present invention, those skilled in the art can make variations or modifications based on the foregoing embodiments.

Claims

1. A stator assembly, the stator assembly comprising a stator core (100), a multi-turn winding (200), and an inter-turn insulation layer disposed on the outer periphery of each turn of the winding. A stator slot (120) is formed in the stator core (100), and the winding (200) is disposed in the stator slot (120). Characterized in that each turn of the winding (200) is formed by parallelly winding a plurality of strands of conductors, and the conductors are rectangular cross-section aluminum conductors. In the same stator slot (120), the cross-sectional area of the first turn of the winding near the slot opening is larger than that of the other turns of the winding. The number of layers of the conductors in the first turn of the winding is greater than that of the conductors in the other turns, and the thickness of the conductors in the first turn of the winding is smaller than that of the conductors in the other turns of the winding.

2. The stator assembly according to claim 1, Characterized in that the stator slot (120) is a parallel slot. In the same stator slot, along the direction from the slot opening to the slot bottom, the cross-sectional area of each turn of the winding (200) gradually decreases, and the number of layers of the conductors of each turn of the winding (200) gradually decreases.

3. The stator assembly according to claim 1, Characterized in that in the same stator slot (120), from the second turn of the winding to the N / 2-th turn of the winding, the cross-sectional area of each turn of the winding (200) gradually decreases, the number of layers of each turn of the winding (200) is the same, the thickness of the conductors parallelly wound in each turn gradually decreases from the second turn of the winding to the N / 2-th turn of the winding. From the N / 2-th turn of the winding to the N-th turn of the winding, the cross-sectional areas of the windings are the same and are all smaller than the cross-sectional areas of the windings from the first turn of the winding to the N / 2-th turn of the winding. The thicknesses of the conductors parallelly wound in the corresponding turns of the windings gradually increase and are all greater than the thicknesses of the conductors parallelly wound in the windings from the first turn of the winding to the N / 2-th turn of the winding.

4. The stator assembly according to claim 1, Characterized in that the groove height hs0 of the stator slot (120) ranges from 5 mm ≤ hs0 ≤ 12 mm, and the groove height hs0 of the stator slot (120) and the groove depth hs2 of the stator slot (120) satisfy the following relationship:

5. The stator assembly according to claim 4, Characterized in that an inter-strand insulation layer is disposed between the plurality of strands of conductors in each turn of the winding (120), and the thickness h of the inter-strand insulation layer ranges from 0 ≤ h ≤ 0.2 mm.

6. The stator assembly according to claim 5, Characterized in that the stator core (100) is cylindrical, the opening of the stator slot (120) faces the radially inner side of the stator core (100), and the outer diameter D of the stator core (100) is greater than 1900 mm and less than 2800 mm.

7. The stator assembly according to claim 1, Characterized in that the stator slot (120) is a parallel opening slot, the cross-sectional shape of each turn of the winding (200) is rectangular, and each turn of the winding (200) is formed by stacking a plurality of strands of conductors in the radial direction of the stator core or stacking them in the circumferential direction of the stator core.

8. A generator, Characterized in that the generator comprises the stator assembly according to any one of claims 1 to 7.

9. The generator according to claim 8, Characterized in that The generator includes a motor housing (410), a stator assembly, and a rotor assembly. The stator assembly is disposed within the motor housing (410), and the rotor assembly is disposed within the stator assembly. The heat generation of the end windings of the generator is higher than that in the middle of the generator. An air inlet (411) and an air outlet (412) are provided on the motor housing (410). The air inlet (411) is located at the axial two ends of the stator assembly, and the air outlet (412) is located in the middle of the stator assembly. An air gap is formed between the stator assembly and the rotor assembly, and the air gap communicates with the slot opening to jointly form an axial ventilation duct. The stator assembly is further provided with a radial ventilation duct, and the radial ventilation duct communicates the axial ventilation duct with the air outlet, so that the ventilation cooling structure matches the distribution of the heat generation of the generator.

10. The generator according to claim 8, wherein, the generator is a semi-direct-drive permanent magnet wind generator, and the frequency range of the motor is 90 Hz to 120 Hz.

11. The stator assembly according to claim 8, wherein, the generator has a ground insulation structure and a conductor insulation structure, and the insulation classes of the ground insulation structure and the conductor insulation structure are class H.

12. A wind power generation set, wherein, the wind power generation set includes a generator, and the generator is the generator according to any one of claims 8-11.

13. The wind generator according to claim 12, wherein, the wind generator is a semi-direct-drive permanent magnet generator.

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