High-speed permanent magnet motor stator winding cooling method

Abstract

The invention discloses a high-speed permanent magnet motor stator winding cooling method which is small in size, low in power consumption and low in temperature rise. According to the high-speed permanent magnet motor stator winding cooling method, a plurality of stator windings are included, each stator winding is of a hollow pipe structure, the stator windings further comprise a plurality of hollow conductors, the adjacent stator windings are electrically connected through the circumferential walls of the hollow conductors so that the stator windings can be connected in series, and the hollow conductors are arranged to be high-temperature nodes and low-temperature nodes in a staggered mode. Inner holes of the high-temperature nodes are communicated through insulating pipes to form a high-temperature pipeline, inner holes of the low-temperature nodes are communicated through insulating pipes to form a low-temperature pipeline, the insulating pipes prevent short circuit of the stator windings and enable the stator windings to have an electromagnetic conversion function, and inner holes of the stator windings are communicated with inner holes of the corresponding hollow conductors; low-temperature cooling liquid is led into the stator winding through the low-temperature pipeline and then discharged through the high-temperature pipeline after absorbing heat.

Description

Technical Field

[0001] The invention relates to the technical field of high-speed motors, and in particular to a method for cooling a stator winding of a high-speed permanent magnet motor. Background Art

[0002] At present, the main cooling methods for high-speed permanent magnet motor stators are air cooling and air-water mixed cooling. As the name suggests, air cooling is to force low-temperature gas into the motor to cool the motor stator windings and silicon steel sheets to achieve the purpose of heat dissipation; while air-water cooling is to pass circulating water through the motor casing to cool the heat of the motor stator silicon steel sheets and part of the windings, and at the same time, pass low-temperature gas into the motor to cool most of the heat of the motor windings. Due to the low heat transfer coefficient of gas, a large heat transfer temperature difference and a large amount of gas are required to ensure the heat dissipation power. Therefore, the temperature of the motor stator winding is usually high and the auxiliary heat dissipation equipment is large in size. Summary of the invention

[0003] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a method for cooling the stator winding of a high-speed permanent magnet motor, which has small size, low power consumption and low temperature rise.

[0004] The object of the present invention is achieved in that: A high-speed permanent magnet motor stator winding cooling method includes a plurality of stator windings, all of which are hollow tube structures, and also includes a plurality of hollow conductors. Adjacent stator windings are electrically connected through the circumferential wall of the hollow conductors, so that the stator windings are connected in series. The plurality of hollow conductors are staggered to form high-temperature nodes and low-temperature nodes. The inner holes of the high-temperature nodes are connected through insulating tubes to form a high-temperature pipeline. The inner holes of the low-temperature nodes are connected through insulating tubes to form a low-temperature pipeline. The insulating tubes prevent the stator winding from short-circuiting, so that the stator winding has an electromagnetic conversion function. The inner hole of each stator winding is connected to the inner hole of the corresponding hollow conductor. The low-temperature coolant is introduced into the stator winding through the low-temperature pipeline to absorb heat and then discharged through the high-temperature pipeline.

[0005] Preferably, the stator winding is made of a hollow copper tube with an insulating varnish on the surface.

[0006] Preferably, the flow area of ​​the low-temperature pipeline is 1.01 times the sum of the flow areas of the stator windings, and the flow area of ​​the high-temperature pipeline is 1.05 to 1.15 times the flow area of ​​the low-temperature pipeline.

[0007] Preferably, the high-temperature pipeline and the low-temperature pipeline form a ring loop respectively, the high-temperature pipeline is connected to the high-temperature equal-diameter branch, and the low-temperature pipeline is connected to the low-temperature equal-diameter branch. A plate heat exchanger is also included. The high-temperature equal-diameter branch and the low-temperature equal-diameter branch are connected to the heating channel of the plate heat exchanger. A circulating pump is provided on the low-temperature equal-diameter branch. The heated channel of the plate heat exchanger is connected to the cooling water inlet and cooling water return.

[0008] Preferably, the coolant flows in two adjacent stator windings in opposite directions.

[0009] Due to the adoption of the above technical solution, the present invention has the following beneficial effects: 1. It solves the problems of poor heat dissipation in the inner layer of the motor stator winding, low heat density and high energy consumption of the traditional cooling method, and can greatly reduce the average temperature of the motor winding and reduce the volume of the heat dissipation auxiliary equipment; 2. Liquid cooling can effectively isolate the motor from the external environment, so that the motor is in a clean and stable working environment, which is conducive to extending the life of the motor; 3. Solve the problem of motor heat dissipation under "zero leakage" requirements (such as refrigerant compressors, helium compressors), and achieve the coexistence of "high leakage requirements" and "low-cost heat dissipation".

[0010] 4. The interior of the motor is not affected by special environments (such as highly corrosive gas environments) and has good universality. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a simplified structural diagram of the winding; Figure 2 It is a structural schematic diagram of the node section; Figure 3 is a schematic diagram of the structure of the winding circuit; Figure 4 This is a schematic diagram of the coolant flow; Figure 5 Schematic diagram of the cooling system.

[0012] Reference numerals In the attached figure, 1: first winding, 2: second winding, 3: third winding, 4: high temperature node, 5: low temperature node, 6: insulating tube, 7: high temperature pipeline, 8: low temperature pipeline, 9: motor housing, 10: high temperature equal diameter branch, 11: plate heat exchanger, 12: cooling water return, 13: cooling water inlet, 14: circulating pump, 15: low temperature equal diameter branch. DETAILED DESCRIPTION

[0013] A high-speed permanent magnet motor stator winding cooling method comprises a plurality of stator windings, wherein the motor stator windings are rectangular coils uniformly distributed around the circumference of a motor shaft in the motor, the stator windings are all hollow tube structures, and also comprise a plurality of hollow conductors, adjacent stator windings are electrically connected through the circumferential walls of the hollow conductors, so that the stator windings are connected in series, the plurality of hollow conductors are staggeredly arranged as high-temperature nodes and low-temperature nodes, the inner holes of the high-temperature nodes are connected through insulating tubes to form a high-temperature pipeline, the inner holes of the low-temperature nodes are connected through insulating tubes to form a low-temperature pipeline, the insulating tubes prevent the stator winding from short-circuiting, so that the stator winding has an electromagnetic conversion function, the inner hole of each stator winding is connected with the inner hole of the corresponding hollow conductor; low-temperature coolant is introduced into the stator winding through the low-temperature pipeline to absorb heat and then discharged through the high-temperature pipeline.

[0014] In order to describe the present invention more conveniently and intuitively, three coils are cut out and described in a row; the actual winding method and connection method are more complicated than this description. Simplified structural form: Figure 1 .

[0015] 1. The motor stator winding adopts a hollow copper tube with insulating paint on the surface; 2. The head and tail of each winding of the motor stator are connected to a large diameter hollow conductor to form a node (such as Figure 2 As shown), ensure that adjacent windings can be normally conducted; 3. The nodes are connected at intervals through insulating tubes to form pipelines. The insulating tubes can effectively prevent winding short circuits. The pipelines are defined as high-temperature pipelines and low-temperature pipelines, and the nodes on the pipelines are called high-temperature nodes and low-temperature nodes.

[0016] principle: 1. The nodes formed by the connected windings and hollow conductors ensure the normal conduction of the current, and the insulating tubes between the high-temperature nodes / low-temperature nodes effectively avoid short circuits between the windings, making the windings have electromagnetic conversion functions. (such as Figure 3 ) 2. The copper tube winding is cooled by insulating coolant inside. The low-temperature coolant is introduced into the winding through the low-temperature pipeline and then discharged through the high-temperature pipeline after absorbing heat. The coolant flows in opposite directions in the adjacent windings. (For example, Figure 4 ) 3. The internal flow area of ​​the low-temperature pipeline is 1.01 times the sum of the internal flow areas of each group of windings, and the flow area of ​​the high-temperature pipeline is 1.05-1.15 times the flow area of ​​the low-temperature pipeline (adjusted according to the characteristics of the coolant). The high and low temperature pipelines each form a circular loop, passing through the motor housing through the equal-diameter three-way branch on the circular ring and connected to the external plate heat exchanger. The other side of the heat exchanger is circulating cooling water for cooling the coolant; a coolant circulation pump is installed on the low-temperature coolant pipe section on the outside of the motor to circulate the coolant and improve the heat exchange efficiency. (such as Figure 5) Except for the nodes which are conductors, the rest of the high and low temperature pipelines are conduits made of insulating materials, including the branches leading out of the motor casing, to ensure the insulation of the windings and the motor.

[0017] 4. According to the heat transfer principle, the heat transfer coefficient of liquid cooling inside the copper tube is higher than that of gas cooling on the surface of the copper wire; and gas cooling can only cool the outermost layer of the winding and cannot directly cool the inner layer of the winding (the inner layer of the winding transfers heat to the outer layer of the winding for cooling through heat transfer), while liquid cooling inside the copper tube can cool the inner and outer layers of the winding (that is, the entire conductor), and the cooling effect is much better than gas cooling. Therefore, the liquid cooling method has a high heat flux density, a small flow rate of coolant required, and low auxiliary power consumption.

[0018] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made in form and details without departing from the scope defined by the claims of the present invention.

Claims

1. A method for cooling a stator winding of a high-speed permanent magnet motor, comprising a plurality of stator windings, characterized in that: The stator windings are all hollow tube structures, and also include a number of hollow conductors. Adjacent stator windings are electrically connected through the circumferential wall of the hollow conductors, so that the stator windings are connected in series. The several hollow conductors are staggered to form high-temperature nodes and low-temperature nodes. The inner holes of the high-temperature nodes are connected through insulating tubes to form high-temperature pipelines. The inner holes of the low-temperature nodes are connected through insulating tubes to form low-temperature pipelines. The insulating tubes prevent the stator windings from short-circuiting, so that the stator windings have electromagnetic conversion functions. The inner holes of each stator winding are connected to the inner holes of the corresponding hollow conductors. The low-temperature coolant is introduced into the stator winding through the low-temperature pipeline to absorb heat and then discharged through the high-temperature pipeline.

2. A high-speed permanent magnet motor stator winding cooling method according to claim 1, characterized in that: The stator winding is made of hollow copper tube with insulating paint on the surface.

3. The method for cooling the stator winding of a high-speed permanent magnet motor according to claim 1, characterized in that: The flow area of ​​the low-temperature pipeline is 1.01 times the sum of the flow areas of each stator winding, and the flow area of ​​the high-temperature pipeline is 1.05 to 1.15 times the flow area of ​​the low-temperature pipeline.

4. The method for cooling the stator winding of a high-speed permanent magnet motor according to claim 1, characterized in that: The high-temperature pipeline and the low-temperature pipeline form a ring loop respectively. The high-temperature pipeline is connected to the high-temperature equal-diameter branch, and the low-temperature pipeline is connected to the low-temperature equal-diameter branch. A plate heat exchanger is also included. The high-temperature equal-diameter branch and the low-temperature equal-diameter branch are connected to the heating channel of the plate heat exchanger. A circulating pump is arranged on the low-temperature equal-diameter branch. The heating channel of the plate heat exchanger is connected to the cooling water inlet and cooling water return.

5. The method for cooling the stator winding of a high-speed permanent magnet motor according to claim 1, characterized in that: The coolant flows in two adjacent stator windings in opposite directions.

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