Method and device for calculating equivalent thermal parameters of motor winding, and server

Abstract

The application provides a motor winding equivalent thermal parameter calculation method, device and server, and relates to the technical field of motor application. The method comprises the following steps: obtaining winding specifications of a motor winding, generating an equivalent round copper wire model of the motor winding based on the winding specifications; according to the principle of equal cross-sectional area, equivalent round copper wires included in the equivalent round copper wire model are equivalent into square units; equivalent parameters are calculated based on the square units, and equivalent thermal parameters of the motor winding are calculated according to the equivalent parameters. The motor winding equivalent thermal parameter calculation method, device and server provided by the application can simplify the modeling of the motor winding, and the winding specifications are fully considered in the simplification process, so that the simplified modeling is more accurate. Furthermore, the use of equivalent square units for calculation can simplify the calculation process, which helps to improve the accuracy of temperature field calculation while ensuring the calculation efficiency.

Description

Technical Field

[0001] This invention relates to the technical field of motor applications, and in particular to a method, apparatus, and server for calculating the equivalent thermal parameters of motor windings. Background Technology

[0002] Electric motors are a widely used industrial product. Their structure generally consists of a stator and a rotor, with the stator containing stator windings used for electromagnetic conversion. Electric motor windings can be divided into shaped windings and loose windings. Loose windings are widely used in low-voltage motors with voltages of 660V and below, including three-phase asynchronous motors, permanent magnet synchronous motors, generators, and stepper motors with frame sizes of 355 and below.

[0003] With the development of electric vehicles, highly integrated equipment, and integrated complete sets of equipment, the requirements for motors are becoming increasingly stringent. Motors need higher power density, smaller size, and higher reliability to meet system integration requirements. However, higher power density and smaller size mean poorer heat dissipation, which increases the motor's temperature rise, reduces insulation durability, and lowers reliability. This is because exceeding the insulation temperature limit by 8°C can halve the insulation life. Therefore, accurate calculation of the temperature rise of each component is crucial in motor design to ensure that the temperature rise does not exceed the insulation class's performance requirements even at maximum operating temperatures.

[0004] The stator winding of the motor is embedded inside the stator core, and copper losses are generated inside the winding. Therefore, the stator winding is the component with the highest temperature rise in the motor. In order to cut off the electrical connection between the stator core and the winding, slot insulation is set between the stator winding and the stator core, while the wires are insulated with varnish film. The heat generated by the motor winding will inevitably be conducted through the insulation. However, the insulation material is relatively not resistant to high temperature. Therefore, the insulation structure of the motor winding is the weak link in the motor's high temperature resistance.

[0005] To accurately calculate the temperature rise of a motor, the finite element method is typically used. This method involves accurately modeling the motor components, then meshing them, assigning boundary conditions and excitation sources, and calculating the thermal parameters of each node for each mesh. When the components are meshed finely, the temperature distribution of different parts of the same component can be obtained.

[0006] Although the finite element method can analyze the temperature rise of a motor, the stator winding coils are not a universal standard, making stator winding modeling relatively difficult. At the same time, the varnish covering makes insulation modeling relatively complex, which not only reduces the efficiency of the motor temperature field thermal calculation but also affects the accuracy of the temperature field calculation. Summary of the Invention

[0007] In view of this, the purpose of the present invention is to provide a method, apparatus and server for calculating the equivalent thermal parameters of motor windings, so as to alleviate the above-mentioned technical problems.

[0008] In a first aspect, embodiments of the present invention provide a method for calculating the equivalent thermal parameters of a motor winding. The method includes: obtaining the winding specifications of the motor winding; generating an equivalent round copper wire model of the motor winding based on the winding specifications; wherein the motor winding includes the stator winding of the motor; the equivalent round copper wire model contains the same number of round copper wires as the coil of the motor winding, and the round copper wires contained in the equivalent round copper wire model are equivalent round copper wires with the same diameter; according to the principle of equal cross-sectional area, the equivalent round copper wires contained in the equivalent round copper wire model are equivalent to square units; calculating equivalent parameters based on the square units, and calculating the equivalent thermal parameters of the motor winding based on the equivalent parameters, wherein the equivalent thermal parameters include equivalent thermal conductivity and equivalent specific heat capacity.

[0009] In conjunction with the first aspect, the present invention provides a first possible implementation of the first aspect, wherein the above method further includes: inputting the equivalent thermal parameters into a pre-established simplified stator winding model, and performing thermal calculation of the temperature field in the simplified stator winding model.

[0010] In conjunction with the first aspect, this embodiment of the invention provides a second possible implementation of the first aspect, wherein the step of generating an equivalent round copper wire model of the motor winding based on the winding specifications includes: extracting coil parameters of the motor winding based on the winding specifications, wherein the coil parameters include the quantity and specifications of the round copper wires, the winding method of the round copper wires, and the enamel film parameters of the round copper wires; converting round copper wires of different diameters into equivalent round copper wires of the same diameter according to the principle of the same cross-sectional area, and making the quantity of the equivalent round copper wires the same as the quantity of round copper wires included in the coil parameters; calculating the parameters of the equivalent round copper wires based on the coil parameters of the motor winding; wherein the parameters of the equivalent round copper wires include: the cross-sectional area of ​​a single equivalent round copper wire without enamel film, the diameter of a single equivalent round copper wire, and the enamel film thickness.

[0011] In conjunction with the second possible implementation of the first aspect, this embodiment of the invention provides a third possible implementation of the first aspect, wherein the step of converting the equivalent round copper wires included in the equivalent round copper wire model into square units according to the principle of equal cross-sectional area includes: extracting the cross-sectional area of ​​a single equivalent round copper wire, and generating a square unit with the same cross-sectional area as the single equivalent round copper wire according to the principle of equal cross-sectional area; wherein, along the radial direction of the square unit, from the outside to the inside, it includes an air layer, an impregnation layer, a varnish layer, and a copper wire layer in sequence.

[0012] In conjunction with the third possible implementation of the first aspect, this embodiment of the invention provides a fourth possible implementation of the first aspect, wherein the step of calculating equivalent parameters based on the square unit includes: calculating the following equivalent parameters based on the square unit: the side length of the square unit occupied by each equivalent round copper wire; the side length of the square occupied by the copper wire layer; the area of ​​the varnish layer outside each equivalent round copper wire; the bilateral thickness of the varnish layer; the bilateral thickness of the impregnation layer; and the bilateral thickness of the air layer.

[0013] In conjunction with the fourth possible implementation of the first aspect, this embodiment of the invention provides a fifth possible implementation of the first aspect, wherein the step of calculating the equivalent thermal parameters of the motor winding based on the equivalent parameters includes: calculating the equivalent thermal conductivity based on the equivalent parameters according to the following formula; wherein the equivalent thermal conductivity is expressed as:

[0014]

[0015] in,

[0016] H1 is the coil length; L1 is the side length of the square unit occupied by each equivalent round copper wire; L2 is the side length of the square occupied by the copper wire layer; Wii represents the bilateral thickness of the enamel layer; Lq represents the bilateral thickness of the impregnation layer; La represents the bilateral thickness of the air layer; kc represents the thermal conductivity of the round copper wire; kw represents the thermal conductivity of the enamel film; kq represents the thermal conductivity of the impregnation layer; and ka represents the thermal conductivity of the air.

[0017] In conjunction with the fifth possible implementation of the first aspect, this embodiment of the invention provides a sixth possible implementation of the first aspect, wherein the step of calculating the equivalent thermal parameters of the motor winding based on the equivalent parameters further includes: calculating the equivalent specific heat capacity using a volume-weighted average of the specific heat capacities of the round copper wire, the varnish film, the impregnation varnish, and the air; wherein the equivalent specific heat capacity is expressed as:

[0018]

[0019] Where Cc represents the specific heat capacity of the round copper wire, Cw represents the specific heat capacity of the enamel film, Cq represents the specific heat capacity of the enamel impregnation, and Ca represents the specific heat capacity of air.

[0020] Secondly, embodiments of the present invention also provide a device for calculating equivalent thermal parameters of a motor winding. The device includes: a first equivalent module, configured to acquire the winding specifications of the motor winding and generate an equivalent round copper wire model of the motor winding based on the winding specifications; wherein the motor winding includes the stator winding of the motor; the equivalent round copper wire model contains the same number of round copper wires as the coil of the motor winding, and the round copper wires contained in the equivalent round copper wire model are equivalent round copper wires with the same diameter; a second equivalent module, configured to convert the equivalent round copper wires contained in the equivalent round copper wire model into square units according to the principle of equal cross-sectional area; and a calculation module, configured to calculate equivalent parameters based on the square units and calculate the equivalent thermal parameters of the motor winding according to the equivalent parameters, wherein the equivalent thermal parameters include equivalent thermal conductivity and equivalent specific heat capacity.

[0021] Thirdly, embodiments of the present invention also provide a server, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the method described in the first aspect above.

[0022] Fourthly, embodiments of the present invention also provide a computer-readable storage medium storing a computer program, wherein the computer program, when executed by a processor, performs the steps of the method described in the first aspect above.

[0023] The embodiments of the present invention bring the following beneficial effects:

[0024] The method, apparatus, and server for calculating equivalent thermal parameters of motor windings provided in this invention can obtain the winding specifications of the motor windings, generate an equivalent round copper wire model of the motor windings based on the winding specifications, and, according to the principle of equal cross-sectional area, convert the equivalent round copper wires included in the equivalent round copper wire model into square units; then calculate the equivalent parameters based on the square units, and calculate the equivalent thermal parameters of the motor windings based on the equivalent parameters. Furthermore, by converting the winding specifications of the motor windings into equivalents during the calculation process, not only can the modeling of the motor windings be simplified, but the winding specifications are also fully considered during the simplification process, making the simplified modeling more accurate. At the same time, further using equivalent square units for calculation can simplify the calculation process, ensuring calculation efficiency while also helping to improve the accuracy of temperature field calculation.

[0025] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention are realized and obtained in accordance with the structures particularly pointed out in the description, claims and drawings.

[0026] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0027] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of a cross-section of the stator winding of an electric motor.

[0029] Figure 2 A schematic diagram of an enameled round copper wire;

[0030] Figure 3 A flowchart illustrating a method for calculating equivalent thermal parameters of a motor winding, provided in an embodiment of the present invention;

[0031] Figure 4 A schematic diagram of a simplified stator winding model provided in an embodiment of the present invention;

[0032] Figure 5 This is a schematic diagram of a square unit structure provided in an embodiment of the present invention;

[0033] Figure 6 A schematic diagram of the structure of a device for calculating the equivalent thermal parameters of a motor winding provided in an embodiment of the present invention;

[0034] Figure 7 This is a schematic diagram of the structure of a server provided in an embodiment of the present invention. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] Typically, the stator windings of an electric motor are embedded inside the stator core, and copper losses are generated within the windings. Therefore, the stator windings are the components with the highest temperature rise in the motor. In order to cut off the electrical connection between the stator core and the windings, slot insulation is installed between the stator windings and the stator core, while the wires are insulated with varnish. The heat generated by the motor windings will inevitably be conducted through the insulation. However, the insulation material is relatively not resistant to high temperatures, so the insulation structure of the motor windings is the weakest link in the motor's high-temperature resistance.

[0037] For ease of understanding, Figure 1 A schematic cross-sectional view of a stator winding of an electric motor is shown, as follows. Figure 1 The diagram shows a stator core 101, stator slots 102, stator slot insulation 103, stator windings 104, slot wedges 105, and slot openings 106. The stator windings are made of enameled round copper wire. Figure 2 The diagram shown is of an enameled round copper wire, which includes a copper conductor 201 and an enamel film 202.

[0038] To accurately calculate the temperature rise of a motor, the finite element method is typically used for stator windings. This method involves accurately modeling the motor components, then meshing them, assigning boundary conditions and excitation sources, and calculating the thermal parameters of each node for each mesh. When the components are meshed finely, the temperature distribution of different parts of the same component can be obtained.

[0039] Compared with the traditional thermal circuit method, the advantages of finite element method are as follows:

[0040] (1) Accurate heat source: It can combine electromagnetic field simulation calculation of motor to reflect the discrete distribution of motor loss and can accurately set the heat source of motor.

[0041] (2) Discrete temperature rise: It can reflect the local temperature rise of the same component and find the extreme point of temperature rise;

[0042] (3) High adaptability: Through personalized modeling of motors, it is possible to calculate the temperature rise of motors with various structures.

[0043] While finite element method (FEM) calculations for motor temperature rise have the advantages mentioned above, they also have the following problems:

[0044] (1) Difficulty in modeling windings: Split-core windings are a type of enameled round copper wire. Taking small and medium-sized motors as an example, the diameter of commonly used round copper wire is 0.63mm-1.5mm. Depending on the different specifications of the motor, the number of round copper wires in each turn of the coil of a small and medium-sized motor can range from dozens to hundreds. In this case, the diameter of the round copper wire is too small relative to the motor. Modeling, subdividing and calculating it will consume a lot of computing resources, especially in the whole machine calculation, where modeling and subdividing are impossible.

[0045] (2) Difficulty in insulation modeling: In temperature field calculation, the enamel film of the enameled round copper wire with poor thermal conductivity is an important parameter. The thickness of the enamel film of the round copper wire is usually only 0.05-0.07mm, which is 1-2 orders of magnitude smaller than the diameter of the round copper wire. Moreover, each copper wire is covered with enamel film, which cannot be calculated by modeling.

[0046] To address the problem of the inability to model enameled round copper wire in temperature field calculations, relevant research has been conducted. Although some progress has been made, these research results generally use multi-layer models for equivalence, but the models are still quite complex. Furthermore, the equivalent models are not based on the actual structure of the windings, which also reduces the accuracy of temperature field calculations.

[0047] Based on this, the present invention provides a method, apparatus and server for calculating the equivalent thermal parameters of motor windings, which can effectively alleviate the above-mentioned technical problems.

[0048] To facilitate understanding of this embodiment, a method for calculating the equivalent thermal parameters of a motor winding disclosed in this embodiment of the invention will first be described in detail.

[0049] In one possible implementation, embodiments of the present invention provide a method for calculating the equivalent thermal parameters of a motor winding, specifically, Figure 3 A flowchart illustrating a method for calculating the equivalent thermal parameters of a motor winding is shown. This method includes the following steps:

[0050] Step S302: Obtain the winding specifications of the motor windings and generate an equivalent round copper wire model of the motor windings based on the winding specifications.

[0051] The motor winding includes the stator winding of the motor; and in this embodiment of the invention, the equivalent round copper wire model has the same number of round copper wires as the coil of the motor winding, and the round copper wires included in the equivalent round copper wire model are equivalent round copper wires with the same diameter.

[0052] Typically, the winding specifications of the motor windings can be obtained based on the electromagnetic design scheme of the motor. For example, the coil is wound with n1 round copper wires of different diameters φ1, φ2, φ3... (excluding enamel film). The enamel film thickness on both sides of the winding is Wi1, Wi2, Wi3..., and the corresponding cross-sectional area of ​​a single conductor with enamel film is Sqφ1, Sqφ2, Sqφ3..., while the area of ​​a conductor without enamel film is Sφ1, Sφ2, Sφ3... etc. Based on these winding specifications, an equivalent round copper wire model corresponding to the motor winding can be generated.

[0053] Step S304: According to the principle of equal cross-sectional area, the equivalent round copper wire included in the equivalent round copper wire model is equivalent to a square unit.

[0054] Step S306: Calculate the equivalent parameters based on the square unit, and calculate the equivalent thermal parameters of the motor winding based on the equivalent parameters;

[0055] In this embodiment of the invention, the equivalent thermal parameters include the equivalent thermal conductivity and the equivalent specific heat capacity.

[0056] The method for calculating the equivalent thermal parameters of a motor winding provided in this invention can obtain the winding specifications of the motor winding, generate an equivalent round copper wire model of the motor winding based on the winding specifications, and, according to the principle of equal cross-sectional area, convert the equivalent round copper wire included in the equivalent round copper wire model into square units; then calculate the equivalent parameters based on the square units, and calculate the equivalent thermal parameters of the motor winding based on the equivalent parameters. Furthermore, by converting the winding specifications of the motor winding into equivalents during the calculation process, not only can the modeling of the motor winding be simplified, but the winding specifications are also fully considered during the simplification process, making the simplified modeling more accurate. At the same time, further using equivalent square units for calculation can simplify the calculation process, ensuring calculation efficiency while also helping to improve the accuracy of temperature field calculation.

[0057] In practical use, the method for calculating the equivalent thermal parameters of motor windings provided in this embodiment of the invention is actually a method for calculating the equivalent thermal parameters of motor windings based on the temperature field finite element method. By using the principle of the same average thermal resistance and combining the basic structure of the motor's stator windings, the equivalent thermal conductivity and equivalent specific heat capacity of copper, varnish film, and impregnation varnish in the stator windings are obtained.

[0058] Furthermore, the method for calculating the equivalent thermal parameters of the motor winding provided in this embodiment of the invention can, after obtaining the equivalent thermal conductivity and equivalent specific heat capacity, input the equivalent thermal parameters, including the equivalent thermal conductivity and equivalent specific heat capacity, into a pre-established simplified stator winding model, and perform thermal calculations of the temperature field in the simplified stator winding model.

[0059] For ease of understanding, Figure 4 The diagram also shows a simplified stator winding model, and... Figure 1 The schematic diagram of the cross-section of the stator winding of the motor shown corresponds to, as follows: Figure 4 As shown, J1 is an equivalent integrated stator winding, i.e., the simplified stator winding model in this embodiment of the invention, based on... Figure 4 The method for calculating the temperature field using the simplified stator winding model shown can be achieved by assigning thermal resistance at the boundary in finite element software. Therefore, the calculation method in this embodiment of the invention does not consider slot insulation modeling, which can minimize the number of meshes in the finite element calculation. Furthermore, by combining the simplified model with the assignment of equivalent thermal parameters, the thermal characteristics of the winding model are ensured to be basically equivalent to those of the actual winding.

[0060] further, Figure 1In the calculation, the slot wedges and stator slot insulation in the stator slots are located at the outer edge of the winding and can be modeled or assigned values ​​separately. Therefore, the portion of the slot wedges and stator slot insulation can be removed from the calculation to obtain the net stator slot area S1 of the motor, i.e. Figure 1 The area enclosed by the stator slot insulation 103 (excluding 103) can effectively simplify the calculation workload.

[0061] Furthermore, when generating the equivalent round copper wire model of the motor winding based on the winding specifications, it is necessary to extract the coil parameters of the motor winding based on the winding specifications. The coil parameters include the quantity and specifications of the round copper wire, the winding method of the round copper wire, and the enamel film parameters of the round copper wire. Then, according to the principle of the same cross-sectional area, round copper wires of different diameters are equivalent to equivalent round copper wires of the same diameter, and the quantity of equivalent round copper wires is the same as the quantity of round copper wires included in the coil parameters. This is to facilitate the calculation of the parameters of the equivalent round copper wires based on the coil parameters of the motor winding. The parameters of the equivalent round copper wires include: the cross-sectional area of ​​a single equivalent round copper wire without enamel film, the diameter of a single equivalent round copper wire, and the enamel film thickness.

[0062] Taking a coil composed of n1 round copper wires of different diameters φ1, φ2, φ3… (excluding enamel coating) wound in parallel as an example, the coil consists of n1 round copper wires of different diameters φ1, φ2, φ3… (excluding enamel coating). The enamel coating thickness on both sides of the winding is Wi1, Wi2, Wi3…, corresponding to the cross-sectional area of ​​a single conductor with enamel coating as Sqφ1, Sqφ2, Sqφ3…, and the area of ​​a conductor without enamel coating as Sφ1, Sφ2, Sφ3…. Based on the principle of the same cross-sectional area, an equivalent round copper wire with diameter φn is used to represent the different diameters φ1, φ2, φ3…, while keeping the number of round copper wires wound in parallel n1 unchanged. In this case, the parameters of the equivalent round copper wire are as follows:

[0063] The cross-sectional area of ​​a single equivalent round copper wire without enamel coating is Sn = (Sφ1 + Sφ2 + Sφ3 + ...) / n1, and the corresponding diameter of a single equivalent round copper wire is... (Excluding paint film), corresponding paint film thickness Among them: Sq=[(Sqφ1-Sφ1)+(Sqφ2-Sφ2)+(Sqφ3-Sφ3)+…] / n1;

[0064] Furthermore, after obtaining the above equivalent round copper wire model, when generating the equivalent square element in step S304, it is necessary to extract the cross-sectional area of ​​a single equivalent round copper wire and generate a square element with the same cross-sectional area as the single equivalent round copper wire according to the principle of equal cross-sectional area; specifically, Figure 5 A schematic diagram of a square unit structure is shown, such as... Figure 5The diagram shows a cross-sectional view of a square cell. Along the radial direction of the square cell, from the outside to the inside, it includes an air layer 501, an impregnation layer 502, a varnish film layer 503, and a copper wire layer 504.

[0065] Furthermore, based on Figure 5 The square element shown is used to calculate the following equivalent parameters when calculating the equivalent parameters:

[0066] (1) The side length of the square unit occupied by each equivalent round copper wire;

[0067] The side length of the square unit occupied by the equivalent round copper wire usually refers to the side length of the outermost square of the square unit. Figure 5 In this context, denoted as L1, its calculation formula can be expressed as:

[0068] Where S1 represents the net area of ​​the stator slot of the motor, and n represents the number of copper wires in the stator slot.

[0069] (2) The side length of the square occupied by the copper wire layer;

[0070] The square area occupied by the copper wire layer refers to... Figure 5 The side length of the square containing the middle copper wire layer, i.e. Figure 5 The side length shown in L2 can be calculated using the following formula: Wherein, Sn represents the cross-sectional area of ​​a single equivalent round copper wire without enamel coating.

[0071] (3) The area of ​​the enamel film layer outside each equivalent round copper wire;

[0072] In this embodiment of the invention, the area of ​​the varnish layer outside the equivalent round copper wire usually refers to Sq in the aforementioned varnish thickness, that is, S2 = Sq;

[0073] (4) Bilateral thickness of the paint film layer;

[0074] in, Figure 5 The cross-sectional view of the square unit shown is equivalent to the equivalent square copper wire corresponding to the equivalent round copper wire. The bilateral thickness of this coating layer is expressed as... Figure 5 Wii, among which, Figure 5 The diagram shown is for a single layer, namely Wii / 2, whose formula is expressed as:

[0075]

[0076] (5) Bilateral thickness of the impregnation layer;

[0077] In the diagram, Lq represents the bilateral thickness of the impregnation layer, and... Figure 5The diagram shown is also a single-layer diagram, namely Lq / 2, where the formula for calculating Lq is:

[0078]

[0079] Wherein, Dp represents the impregnation coefficient of the winding in the stator slot of the motor. The impregnation coefficient Dp of the winding in the stator slot of the motor can usually be obtained according to the impregnation condition of the motor. Moreover, depending on the level of impregnation process, the impregnation coefficient is usually between 0.7 and 0.9.

[0080] (6) Bilateral thickness of the air layer.

[0081] In this embodiment of the invention, the bilateral thickness of the air layer is expressed as La = L1 - L2 - Wii - Lq.

[0082] Based on the above equivalent parameters, the equivalent thermal parameters of the motor winding can be further calculated. Specifically, when calculating the equivalent thermal conductivity, since the stator slot is an axisymmetric structure, the heat flow trajectory at the axis coincides with the axis of symmetry. A conductor unit at the center of the stator slot axis is selected. The heat path from this position to the bottom of the slot is perpendicular to the side of the square. In fact, there is no difference in the material structure in all directions at this position, that is, there is no difference in thermal resistance per unit length. Therefore, the thermal resistance unit at all positions can be calculated using the thermal resistance unit on the path of the axis of symmetry. Since it is an equivalent thermal resistance, the contact thermal resistance is not considered for the time being. When the coil length is H1, the equivalent thermal conductivity can be calculated according to the following formula based on the equivalent parameters.

[0083] Wherein, the equivalent thermal conductivity is expressed as k:

[0084]

[0085] in,

[0086]

[0087] H1 is the coil length; L1 is the side length of the square unit occupied by each equivalent round copper wire; L2 is the side length of the square occupied by the copper wire layer; Wii represents the bilateral thickness of the enamel layer; Lq represents the bilateral thickness of the impregnation layer; La represents the bilateral thickness of the air layer; kc represents the thermal conductivity of the round copper wire; kw represents the thermal conductivity of the enamel film; kq represents the thermal conductivity of the impregnation layer; and ka represents the thermal conductivity of the air.

[0088] In practical applications, the thermal conductivity kq and specific heat capacity Cq of the motor varnish can be obtained based on the varnish material of the motor; and the thermal conductivity kc and specific heat capacity Cc of the round copper wire of the stator winding and the thermal conductivity kw and specific heat capacity Cw of the varnish film can be obtained based on the material of the stator winding.

[0089] Furthermore, in calculating the equivalent specific heat capacity, in this embodiment of the invention, the equivalent specific heat capacity is calculated by a volume-weighted average of the specific heat capacities of round copper wire, varnish film, impregnation varnish and air.

[0090] The equivalent specific heat capacity is expressed as:

[0091]

[0092] Where Cc represents the specific heat capacity of the round copper wire, Cw represents the specific heat capacity of the enamel film, Cq represents the specific heat capacity of the enamel impregnation, and Ca represents the specific heat capacity of air.

[0093] To facilitate understanding, a three-phase asynchronous motor of H132M2-6-5.5kW will be used as an example to explain in detail the calculation method of the equivalent thermal parameters of the motor windings provided in this embodiment of the invention. It is also assumed that the stator slot type of the three-phase asynchronous motor is as follows: Figure 1 As shown, the net area of ​​the stator slot is S1 = 131.509 mm2.

[0094] Furthermore, assuming the impregnation material of the motor is a fast-curing insulating impregnating resin with a thermal conductivity of kq = 0.2 W / m², -1 K -1 Specific heat capacity Cq = 2000 J*kg -1 K -1 The impregnation coefficient of the winding, Dp, is 0.8.

[0095] Each slot contains n1 = 90 round copper wires, including 45 wires with φ1 = 0.9 mm and 45 wires with φ2 = 1 mm. The equivalent cross-sectional area of ​​a single round copper wire is:

[0096] Sn=45*π*(0.45*0.45+0.5*0.5) / 90=0.7108mm 2 ,

[0097] The corresponding diameter of a single equivalent round copper wire

[0098] The paint film thickness corresponding to φ1 is 0.05mm, and the paint film thickness corresponding to φ2 is 0.07mm. Therefore, the equivalent paint film thickness Wi = 0.0605, where Sq = 0.0932mm. 2 The thermal conductivity of the round copper wire in the stator winding is kc = 370 W / m. -1 K -1 Specific heat capacity Cc = 385 J*kg -1 K -1 The thermal conductivity of the paint film is kw = 0.2 W / m. -1 K -1 Specific heat capacity Cw = 2000 J*kg -1 K -1;

[0099] The side length of the equivalent square unit occupied by each equivalent round copper wire is expressed as:

[0100]

[0101] The side length of the square occupied by the copper wire layer of each equivalent square unit of the equivalent round copper wire.

[0102] The area of ​​the enamel film layer outside each equivalent round copper wire is S2=Sq=0.0932mm2;

[0103] The bilateral thickness of the enamel layer when equivalent to a square unit wire is expressed as:

[0104]

[0105] When equivalent to a square unit wire, the bilateral thickness of the enamel layer is expressed as:

[0106]

[0107] The bilateral thickness of the air layer when equivalent to a square unit conductor is expressed as: La = 1.2088 - 0.8431 - 0.0536 - 0.2565 = 0.0556 mm; the thermal conductivity of air is ka = 0.023 W / m². -1 K -1 Specific heat capacity Ca = 1000 J / kg -1 K -1 ;

[0108] Substitute into the formula to calculate the equivalent thermal conductivity:

[0109]

[0110]

[0111]

[0112]

[0113]

[0114] The equivalent specific heat capacity calculated using the formula is expressed as follows:

[0115]

[0116]

[0117] Calculations show that the equivalent thermal conductivity of the winding is 319.0037 W / m². -1 K -1The equivalent specific heat capacity is 1473.5081 J*kg. -1 K -1 .

[0118] By performing thermal calculations using the equivalent thermal conductivity and equivalent specific heat capacity inside the stator slots in the simplified stator winding model, the problem of not being able to model and mesh the windings and varnish film in finite element temperature field analysis can be effectively solved, greatly reducing the computational load of the finite element temperature field. At the same time, by equivalencing the numerical parameters of the slot structure, the influence of material differences, structural size differences, and thermally related parameter differences of the winding copper wire, varnish film, impregnation varnish, and air on the thermal performance of the motor windings is reflected, which also helps to improve the accuracy of temperature field calculations.

[0119] Furthermore, based on the above embodiments, this invention provides a device for calculating the equivalent thermal parameters of motor windings. Figure 6 A schematic diagram of a device for calculating the equivalent thermal parameters of a motor winding is shown. The device includes:

[0120] The first equivalent module 60 is used to obtain the winding specifications of the motor winding and generate an equivalent round copper wire model of the motor winding based on the winding specifications; wherein, the motor winding includes the stator winding of the motor; the equivalent round copper wire model has the same number of round copper wires as the coil of the motor winding, and the round copper wires contained in the equivalent round copper wire model are equivalent round copper wires with the same diameter.

[0121] The second equivalent module 62 is used to convert the equivalent round copper wires included in the equivalent round copper wire model into square units according to the principle of equal cross-sectional area.

[0122] The calculation module 64 is used to calculate the equivalent parameters based on the square unit, and to calculate the equivalent thermal parameters of the motor winding according to the equivalent parameters, wherein the equivalent thermal parameters include the equivalent thermal conductivity and the equivalent specific heat capacity.

[0123] The calculation device for equivalent thermal parameters of motor windings provided in this embodiment of the invention has the same technical features as the calculation method for equivalent thermal parameters of motor windings provided in the above embodiments, so it can also solve the same technical problems and achieve the same technical effects.

[0124] Furthermore, embodiments of the present invention also provide a server, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the above-described method.

[0125] This invention also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, performs the steps of the above-described method.

[0126] Furthermore, this embodiment of the invention also provides a schematic diagram of a server structure, such as... Figure 7 The diagram shows the structure of the server, which includes a processor 71 and a memory 70. The memory 70 stores computer-executable instructions that can be executed by the processor 71, and the processor 71 executes the computer-executable instructions to implement the above-described method.

[0127] exist Figure 7 In the illustrated embodiment, the server further includes a bus 72 and a communication interface 73, wherein the processor 71, the communication interface 73, and the memory 70 are connected via the bus 72.

[0128] The memory 70 may include high-speed random access memory (RAM) or non-volatile memory, such as at least one disk storage device. Communication between this system network element and at least one other network element is achieved through at least one communication interface 73 (which can be wired or wireless), such as the Internet, wide area network, local area network, metropolitan area network, etc. The bus 72 may be an ISA (Industry Standard Architecture) bus, a PCI (Peripheral Component Interconnect) bus, or an EISA (Extended Industry Standard Architecture) bus, etc. The bus 72 can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 7 The symbol is represented by a single double-headed arrow, but this does not mean that there is only one bus or one type of bus.

[0129] Processor 71 may be an integrated circuit chip with signal processing capabilities. In implementation, each step of the above method can be completed by the integrated logic circuitry in the hardware of processor 71 or by software instructions. The processor 71 can be a general-purpose processor, including a Central Processing Unit (CPU), a Network Processor (NP), etc.; it can also be a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field-Programmable Gate Array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the method disclosed in the embodiments of this invention can be directly implemented by a hardware decoding processor, or implemented by a combination of hardware and software modules in the decoding processor. The software modules can reside in random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, or other mature storage media in the art. The storage medium is located in the memory, and the processor 71 reads the information in the memory and uses its hardware to complete the aforementioned method.

[0130] The computer program product of the method, apparatus and server for calculating the equivalent thermal parameters of motor windings provided in the embodiments of the present invention includes a computer-readable storage medium storing program code. The instructions included in the program code can be used to execute the methods described in the preceding method embodiments. For specific implementation, please refer to the method embodiments, which will not be repeated here.

[0131] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working process of the device described above can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0132] Furthermore, in the description of the embodiments of the present invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention based on the specific circumstances.

[0133] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, essentially, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0134] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0135] Finally, it should be noted that the above embodiments are merely specific implementations of the present invention, used to illustrate the technical solutions of the present invention, and not to limit it. The scope of protection of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments within the technical scope disclosed in the present invention, or make equivalent substitutions for some of the technical features; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for calculating the equivalent thermal parameters of a motor winding, characterized in that, The method includes: Obtain the winding specifications of the motor windings, and generate an equivalent round copper wire model of the motor windings based on the winding specifications; wherein, the motor windings include the stator windings of the motor; the equivalent round copper wire model contains the same number of round copper wires as the coils of the motor windings, and the round copper wires contained in the equivalent round copper wire model are equivalent round copper wires with the same diameter. Based on the principle of equal cross-sectional area, the equivalent round copper wires included in the equivalent round copper wire model are equivalent to square units; The equivalent parameters are calculated based on the square unit, and the equivalent thermal parameters of the motor winding are calculated based on the equivalent parameters, wherein the equivalent thermal parameters include the equivalent thermal conductivity and the equivalent specific heat capacity; The step of converting the equivalent round copper wires included in the equivalent round copper wire model into square units according to the principle of equal cross-sectional area includes: Extract the cross-sectional area of ​​a single equivalent round copper wire, and generate square units with the same cross-sectional area as the single equivalent round copper wire according to the principle of equal cross-sectional area; The square unit, from the outside to the inside, includes an air layer, an impregnation layer, a paint film layer, and a copper wire layer in the radial direction. The steps for calculating equivalent parameters based on the square element include: The following equivalent parameters are calculated based on the square element: The side length of the square unit occupied by each of the equivalent round copper wires; The side length of the square occupied by the copper wire layer; The area of ​​the enamel film layer outside each of the aforementioned equivalent round copper wires; The bilateral thickness of the paint film layer; The bilateral thickness of the impregnation layer; The bilateral thickness of the air layer; The steps of calculating the equivalent thermal parameters of the motor winding based on the equivalent parameters include: The equivalent thermal conductivity is calculated according to the following formula based on the equivalent parameters; The equivalent thermal conductivity is expressed as: k ； in, ; ; ; ; H1 is the coil length; L1 is the side length of the square unit occupied by each equivalent round copper wire; L2 is the side length of the square occupied by the copper wire layer; Wii represents the bilateral thickness of the enamel layer; Lq represents the bilateral thickness of the impregnation layer; La represents the bilateral thickness of the air layer; kc represents the thermal conductivity of the round copper wire; kw represents the thermal conductivity of the enamel film; kq represents the thermal conductivity of the impregnation layer; and ka represents the thermal conductivity of the air. The step of calculating the equivalent thermal parameters of the motor winding based on the equivalent parameters further includes: The equivalent specific heat capacity is calculated by using a volume-weighted average of the specific heat capacities of the round copper wire, the paint film, the impregnation paint, and the air. The equivalent specific heat capacity is expressed as: Where Cc represents the specific heat capacity of the round copper wire, Cw represents the specific heat capacity of the enamel film, Cq represents the specific heat capacity of the enamel impregnation, and Ca represents the specific heat capacity of air.

2. The method according to claim 1, characterized in that, The method further includes: The equivalent thermal parameters are input into a pre-established simplified stator winding model, and the thermal calculation of the temperature field is performed in the simplified stator winding model.

3. The method according to claim 1, characterized in that, The steps of generating an equivalent round copper wire model of the motor winding based on the winding specifications include: The coil parameters of the motor winding are extracted based on the winding specifications, wherein the coil parameters include the quantity and specifications of the round copper wire, the winding method of the round copper wire, and the enamel film parameters of the round copper wire. Based on the principle of having the same cross-sectional area, the round copper wires of different diameters are equivalent to the equivalent round copper wires of the same diameter, and the number of the equivalent round copper wires is the same as the number of round copper wires included in the coil parameters. The parameters of the equivalent round copper wire are calculated based on the coil parameters of the motor winding; wherein, the parameters of the equivalent round copper wire include: the cross-sectional area of ​​a single equivalent round copper wire without enamel film, the diameter of a single equivalent round copper wire, and the enamel film thickness.

4. A device for calculating the equivalent thermal parameters of an electric motor winding, characterized in that, The device includes: The first equivalent module is used to obtain the winding specifications of the motor winding and generate an equivalent round copper wire model of the motor winding based on the winding specifications; wherein, the motor winding includes the stator winding of the motor; the equivalent round copper wire model has the same number of round copper wires as the coil of the motor winding, and the round copper wires contained in the equivalent round copper wire model are equivalent round copper wires with the same diameter. The second equivalent module is used to convert the equivalent round copper wires included in the equivalent round copper wire model into square units according to the principle of equal cross-sectional area. The calculation module is used to calculate the equivalent parameters based on the square unit, and to calculate the equivalent thermal parameters of the motor winding according to the equivalent parameters, wherein the equivalent thermal parameters include the equivalent thermal conductivity and the equivalent specific heat capacity; The step of converting the equivalent round copper wires included in the equivalent round copper wire model into square units according to the principle of equal cross-sectional area includes: Extract the cross-sectional area of ​​a single equivalent round copper wire, and generate square units with the same cross-sectional area as the single equivalent round copper wire according to the principle of equal cross-sectional area; The square unit, from the outside to the inside, includes an air layer, an impregnation layer, a paint film layer, and a copper wire layer in the radial direction. The steps for calculating equivalent parameters based on the square element include: The following equivalent parameters are calculated based on the square element: The side length of the square unit occupied by each of the equivalent round copper wires; The side length of the square occupied by the copper wire layer; The area of ​​the enamel film layer outside each of the aforementioned equivalent round copper wires; The bilateral thickness of the paint film layer; The bilateral thickness of the impregnation layer; The bilateral thickness of the air layer; The steps of calculating the equivalent thermal parameters of the motor winding based on the equivalent parameters include: The equivalent thermal conductivity is calculated according to the following formula based on the equivalent parameters; The equivalent thermal conductivity is expressed as: k ； in, ; ; ; ; H1 is the coil length; L1 is the side length of the square unit occupied by each equivalent round copper wire; L2 is the side length of the square occupied by the copper wire layer; Wii represents the bilateral thickness of the enamel layer; Lq represents the bilateral thickness of the impregnation layer; La represents the bilateral thickness of the air layer; kc represents the thermal conductivity of the round copper wire; kw represents the thermal conductivity of the enamel film; kq represents the thermal conductivity of the impregnation layer; and ka represents the thermal conductivity of the air. The step of calculating the equivalent thermal parameters of the motor winding based on the equivalent parameters further includes: The equivalent specific heat capacity is calculated by using a volume-weighted average of the specific heat capacities of the round copper wire, the paint film, the impregnation paint, and the air. The equivalent specific heat capacity is expressed as: Where Cc represents the specific heat capacity of the round copper wire, Cw represents the specific heat capacity of the enamel film, Cq represents the specific heat capacity of the enamel impregnation, and Ca represents the specific heat capacity of air.

5. A server, characterized in that, The method includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the method described in any one of claims 1-3.

6. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, which, when executed by a processor, performs the steps of the method described in any one of claims 1-3.

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