A high-voltage motor stator coil insulation system and a method of making the same

Abstract

The application relates to a high-voltage motor stator coil insulation system, which comprises a straight section and an end section, the straight section and the end section respectively comprising a copper coil, turn-to-turn insulation wrapped outside the copper coil, a main insulation layer wrapped outside the turn-to-turn insulation, and a protective layer wrapped outside the main insulation layer; wherein the main insulation layer is formed by mica tape and epoxy VPI resin curing, the epoxy VPI resin is made of nano powder, a dispersing agent and epoxy resin, and the raw material of the epoxy VPI resin does not contain anhydride. The high-voltage motor stator coil insulation system has better heat conduction performance and electric insulation performance, can significantly reduce the temperature rise of the high-voltage motor during operation, prolong the service life, and has better application process.

Description

Technical Field

[0001] This invention specifically relates to an insulation system for the stator coil of a high-voltage motor and its preparation method. Background Technology

[0002] With the development of motor manufacturing technology, there is a growing demand for higher power motors while maintaining a compact structure. This leads to increased heat generation during operation, resulting in excessive temperature rise in the motor's insulation system. High temperatures are a significant cause of reduced electrical and mechanical performance and lifespan of the insulation, directly impacting motor efficiency. Currently, domestic high-voltage motors primarily rely on improved heat dissipation to reduce temperature rise. However, this inevitably increases motor size and manufacturing costs, significantly limiting unit capacity. Therefore, fundamentally improving motor heat dissipation to reduce temperature rise, and enhancing electrical insulation performance and lifespan, has become a pressing issue for modern motor technology development. Summary of the Invention

[0003] The purpose of this invention is to provide a high-voltage motor stator coil insulation system with high thermal conductivity, excellent electrical insulation performance, and long service life, as well as its preparation method.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] A high-voltage motor stator coil insulation system includes a straight section and an end section. The straight section and the end section respectively include a copper coil, inter-turn insulation covering the outside of the copper coil, a main insulation layer covering the outside of the inter-turn insulation, and a protective layer covering the outside of the main insulation layer. The main insulation layer is formed by curing mica tape and epoxy VPI resin. The epoxy VPI resin is made of nanoparticles, dispersants, and epoxy resin. The raw materials of the epoxy VPI resin do not contain acid anhydrides.

[0006] Preferably, the epoxy resin is selected from epoxy-modified polyesterimide impregnation resin.

[0007] Preferably, the nanoparticles are selected from one or more of boron nitride, aluminum oxide, and aluminum nitride.

[0008] More preferably, the particle size of the nanoparticles is 10-80 nm, such as 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, etc.

[0009] Preferably, the dispersant is selected from one or more of BYK142 dispersant, BYK110 dispersant, KH550 dispersant, and KH560 dispersant.

[0010] Preferably, the mass ratio of epoxy resin: nanoparticles: dispersant is 100:(15-25):(0.5-1.5).

[0011] More preferably, the mass ratio of epoxy resin: nanoparticles: dispersant is 100:(18-22):(0.8-1.2).

[0012] More preferably, the mass ratio of epoxy resin: nanoparticles: dispersant is 100:(19-21):(0.9-1.1).

[0013] Preferably, the mica tape is wrapped in a semi-overlapping manner, and the number of wrapping layers is 5 to 9.

[0014] More preferably, the mica tape has a thickness of 0.1–0.2 mm and a thermal conductivity ≥0.4 W / (mK).

[0015] More preferably, the thickness of the mica strip is 0.12 to 0.17 mm.

[0016] Preferably, the thermal conductivity of the main insulating layer is 0.35 to 0.5 W / (mK).

[0017] More preferably, the thermal conductivity of the main insulating layer is 0.4 to 0.5 W / (mK).

[0018] More preferably, the thermal conductivity of the main insulating layer is 0.45 to 0.5 W / (mK).

[0019] According to some preferred embodiments, the preparation method of the epoxy VPI resin includes first homogenizing and emulsifying the nanoparticles, dispersant, and epoxy resin, and then grinding and dispersing them; wherein the rotation speed of the homogenizing and emulsifying is controlled at 4000-6000 r / min and the time is 1-2 h.

[0020] More preferably, during the homogenization, emulsification, and grinding dispersion, the temperature of the system materials is below 60°C.

[0021] More preferably, the nanoparticles milled and dispersed into the system have a particle size of less than 80 nm.

[0022] Preferably, the inter-turn insulation is formed by wrapping 1 to 4 layers of polyester film-reinforced mica tape with a thickness of 0.03 to 0.09 mm in half-overlap.

[0023] More preferably, the inter-turn insulation is formed by wrapping 1 to 3 layers of polyester film-reinforced mica tape with a thickness of 0.04 to 0.07 mm in half-overlap.

[0024] Preferably, the thickness of the inter-turn insulation is 0.4 to 0.45 mm.

[0025] Preferably, the straight section further includes a low-resistance anti-corona layer and a high-resistance anti-corona layer sequentially covering the outside of the main insulation layer. The protective layer is disposed outside the high-resistance anti-corona layer. The low-resistance anti-corona layer is formed by wrapping a low-resistance anti-corona strip with a thickness of 0.05 to 0.11 mm in 1 to 2 layers of half-overlapping wrapping. The high-resistance anti-corona layer is formed by wrapping a high-resistance anti-corona strip with a thickness of 0.1 to 0.2 mm in 1 to 2 layers of half-overlapping wrapping.

[0026] More preferably, the low-resistance anti-corona tape is a polyester nonwoven fabric-based low-resistance anti-corona tape.

[0027] More preferably, the high-resistance anti-corona tape is a polyester nonwoven high-resistance anti-corona tape filled with SiC particle adhesive, with a thickness of 0.1-0.2 mm.

[0028] More preferably, the wrapping area of ​​the high-resistance anti-corona tape extends from the end of the low-resistance anti-corona tape to the end of the stator coil. The high-resistance anti-corona layer further enhances the anti-corona effect during stator coil operation.

[0029] Preferably, the end also includes a stator coil lead arranged in parallel with the copper coil, the outside of which is sequentially covered by the inter-turn insulation and the polyester fiber felt, and the main insulation layer is disposed outside the polyester fiber felt and the inter-turn insulation on the copper coil.

[0030] More preferably, the protective layer is formed by wrapping with polyester cable ties.

[0031] More preferably, the protective layer is formed by winding 1 to 2 layers in a semi-overlapping manner. The protective layer enables the stator coil to tightly lock the epoxy VPI resin within the main insulation layer during the curing process, reducing epoxy VPI resin loss and enhancing the stability of the main insulation layer.

[0032] Preferably, the high-voltage motor is a high-voltage motor of 6kV or above.

[0033] Another aspect of the present invention provides a method for preparing a high-voltage motor stator coil insulation system as described above, comprising the following preparation steps: (1) wrapping polyester film reinforcing mica tape around the straight portion, the copper coil at the end, and the stator coil lead at the end of the high-voltage motor stator coil to form inter-turn insulation; (2) wrapping mica tape around the outside of the inter-turn insulation, impregnating it with epoxy VPI resin and then curing it with the mica tape to form a main insulation layer, wherein the raw material of the epoxy VPI resin does not contain acid anhydride, and the preparation method of the epoxy VPI resin includes homogenizing and emulsifying nanoparticles, dispersant, and epoxy resin, and then grinding and dispersing them; controlling the curing temperature to be 160-170°C and the time to be 8-13h; (3) wrapping a protective layer around the outside of the main insulation layer.

[0034] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0035] The high-voltage motor stator coil insulation system of the present invention has better thermal conductivity and electrical insulation performance, which can significantly reduce the temperature rise of the high-voltage motor during operation, extend its service life, and has better processability. Attached Figure Description

[0036] Figure 1 This is a structural diagram of the high-voltage motor stator coil insulation system of the present invention;

[0037] Figure 2 for Figure 1 Schematic diagram of the sectional view along the central AA direction;

[0038] Figure 3 for Figure 1 Schematic diagram of the BB-direction section;

[0039] Among them, 1. Copper coil; 2. Inter-turn insulation; 3. Main insulation layer; 4. Low resistance anti-corona layer; 5. High resistance anti-corona layer; 6. Polyester binding tape; 7. Stator coil lead wire; 8. Polyester fiber felt. Detailed Implementation

[0040] Currently, there is no high thermal conductivity insulation system specifically designed for high-voltage motors. Through research, the inventors have discovered that improving the thermal conductivity of the main insulation layer can significantly enhance the thermal conductivity of the insulation system. Generally, the main insulation layer is formed by curing mica tape and impregnating resin. However, the mica tape and impregnating resin in existing main insulation layers, which have good processability, generally have poor thermal conductivity. Although some impregnating resins possess certain thermal conductivity, their processability is poor, failing to meet the requirements of high-voltage motors and limiting their practical application. For example, the nano-modified epoxy vacuum pressure impregnating resin in patent ZL201210187846.1 is prone to moisture absorption and rapid viscosity increase during practical application, making it unsuitable for high-voltage motors.

[0041] The inventors prepared a high thermal conductivity epoxy VPI resin by modifying epoxy resin, and then cured the epoxy VPI resin with mica tape to form the main insulation layer. By designing the inter-turn insulation, protective layer, etc., a high-voltage motor stator coil insulation system was obtained. It not only has good processability, but also has good thermal conductivity and long service life, and is especially suitable for high-voltage motors. The following is a further discussion of the solution of this application.

[0042] According to some specific and preferred embodiments, a high-voltage motor stator coil insulation system includes a straight section and an end section; wherein, the straight section includes a plurality of copper coils 1 constituting the stator coil, inter-turn insulation 2 respectively covering the outer periphery of each copper coil 1, a main insulation layer 3 covering the outer periphery of the inter-turn insulation 2, and a low-resistance anti-corona layer 4, a high-resistance anti-corona layer 5, and a polyester binding tape 6 sequentially covering the outer periphery of the main insulation layer 3.

[0043] The end includes multiple copper coils 1 constituting the stator coil, stator coil leads 7 arranged in parallel with the copper coils 1, inter-turn insulation 2 covering the outer periphery of each copper coil 1 and the outer periphery of the stator coil lead 7, polyester fiber felt 8 covering the outer periphery of the inter-turn insulation 2 on the stator coil lead 7, main insulation layer 3 covering the outer periphery of the inter-turn insulation 2 and the polyester fiber felt 8, and polyester binding tape 6 covering the outer periphery of the main insulation layer 3.

[0044] The aforementioned main insulating layer 3 is formed by curing mica tape and epoxy VPI resin; wherein, the preparation method of epoxy VPI resin includes the following steps:

[0045] (1) Add a certain amount of nanopowder, dispersant and epoxy resin to the high-speed homogenizing emulsifier, adjust the speed to 4000-6000r / min, homogenize and emulsify for 1-2h, and pass cooling water during the process to control the material temperature to be below 60℃.

[0046] (2) Transfer the homogenized emulsified material from step (1) to a high-efficiency grinding equipment and grind and disperse it until the average particle size of the nanoparticles is less than 80 nm. After filtration, epoxy VPI resin is obtained. Cooling water is passed through during the grinding process to control the material temperature below 60°C.

[0047] The solution of the present invention has at least the following advantages:

[0048] (1) The high-voltage motor stator coil insulation system of the present invention effectively improves its thermal conductivity and heat dissipation performance through the design of inter-turn insulation, main insulation layer and protective layer, significantly reduces the temperature rise of high-voltage motor and extends its service life. The insulation system of the present invention also has better electrical insulation performance and application processability.

[0049] (2) The thermal conductivity of the conventional main insulation layer is about 0.20 W / (mK), while the thermal conductivity of the main insulation layer obtained by the present invention is 0.35 to 0.50 W / (mK), which is more than double.

[0050] (3) The main insulating layer preparation process in this invention is simple and the raw materials are readily available. High thermal conductivity epoxy VPI resin can be obtained by modifying the existing commercially available epoxy resin with nanopowder and dispersant. It has good processability and good wetting effect.

[0051] (4) The high-voltage motor using the insulation system of the present invention can reduce the temperature rise by about 10K compared with the high-voltage motor using the conventional insulation system, and reduce the dielectric loss and partial discharge by 20-40%, which is beneficial to improving the electrical performance and electrothermal aging life of the high-voltage motor, and further improving the operational reliability of the high-voltage motor.

[0052] (5) The stator coil insulation system of the present invention is suitable for high voltage motors of 6kV and above, and meets the high power operation requirements of high voltage motors.

[0053] The present invention will be further described below with reference to embodiments. However, the present invention is not limited to the following embodiments. The implementation conditions used in the embodiments can be further adjusted according to different requirements of specific applications, and the implementation conditions not specified are conventional conditions in the industry. The technical features involved in the various embodiments of the present invention can be combined with each other as long as they do not conflict with each other.

[0054] Example 1

[0055] like Figure 1 As shown, a high-voltage motor stator coil insulation system includes a straight section and an end section, wherein a cross-sectional schematic diagram of the straight section is shown below. Figure 2 As shown, the straight section includes multiple copper coils 1 constituting the stator coil, inter-turn insulation 2 respectively covering the outer periphery of each copper coil 1, a main insulation layer 3 covering the outer periphery of the inter-turn insulation 2, and a low-resistance anti-corona layer 4, a high-resistance anti-corona layer 5, and a polyester binding tape 6 sequentially covering the outer periphery of the main insulation layer 3.

[0056] A schematic diagram of the end section is shown below. Figure 3 As shown, the end includes multiple copper coils 1 constituting the stator coil, stator coil leads 7 arranged in parallel with the copper coils 1, inter-turn insulation 2 covering the outer periphery of each copper coil 1 and the outer periphery of the stator coil leads 7, polyester fiber felt 8 covering the outer periphery of the inter-turn insulation 2 on the stator coil leads 7, main insulation layer 3 covering the outer periphery of the inter-turn insulation 2 and the polyester fiber felt 8, and polyester binding tape 6 covering the outer periphery of the main insulation layer 3.

[0057] The aforementioned inter-turn insulation 2 is made of mica tape reinforced with polyester film with a thickness of 0.40 to 0.45 mm and a thickness of 0.06 mm, wrapped in two and a half layers. The polyester film reinforced mica tape is JF-5442-1D mica tape produced by Suzhou Jufeng Electrical Insulation System Co., Ltd.

[0058] The above-mentioned main insulation layer 3 is made of high thermal conductivity mica tape wrapped in seven and a half layers and then impregnated with high thermal conductivity epoxy VPI resin and cured. The curing temperature is 165℃ and the time is 12h. The high thermal conductivity mica tape is a glass cloth reinforced high thermal conductivity low adhesive mica tape with a thickness of 0.14mm produced by Suzhou Jufeng Electrical Insulation System Co., Ltd., model JF-5442-1HTC. The preparation method of high thermal conductivity epoxy VPI resin includes the following steps: (1) Weigh 3kg of aluminum oxide with a particle size of about 30nm, 2kg of silicon dioxide with a particle size of about 50nm, 0.25kg of BYK142 dispersant, and 25kg of epoxy VPI resin with brand name JF-9956-3 (manufacturer is Suzhou Jufeng Electrical Insulation System Co., Ltd.) and add them to the high-speed homogenizing emulsification kettle. Adjust the speed to 5000r / min and homogenize for 1.5h. Cooling water is passed through during the process to control the material temperature below 60℃. (2) Transfer the product obtained in step (1) to a high-efficiency grinding equipment and grind and disperse it until the average particle size of the nanoparticles is less than 80nm (cooling water is passed through during the process to control the material temperature below 60℃). After filtration, high thermal conductivity epoxy VPI resin is obtained.

[0059] The aforementioned low-resistance anti-corona layer 4 is made by wrapping a 0.08mm thick low-resistance anti-corona tape around the main insulation layer 3 of the straight section of the coil in a semi-overlapping manner; wherein, the low-resistance anti-corona tape is the JF-CT low-resistance anti-corona tape produced by Suzhou Jufeng Electrical Insulation System Co., Ltd.

[0060] The aforementioned high-resistance anti-corona layer 5 is made by wrapping a 0.14mm thick high-resistance anti-corona tape in a half-overlap manner from the end of the low-resistance anti-corona layer 4 to the end of the stator coil; wherein, the high-resistance anti-corona tape is the JF-SC high-resistance anti-corona tape produced by Suzhou Jufeng Electrical Insulation System Co., Ltd.

[0061] The aforementioned polyester fiber felt 8 is fitted around the outer periphery of the stator coil lead 7, making the root of the stator coil lead 7 fit more tightly with the end of the stator coil, preventing air gap discharge caused by gaps during motor operation; the polyester fiber felt 8 is commercially available.

[0062] The aforementioned polyester binding tape 6, after the high-resistance anti-corona layer 5 in the straight section and the main insulation layer 3 at the end are wound, is then wrapped around the outer periphery. After the stator coil is impregnated by vacuum pressure, the polyester binding tape 6 can lock the impregnating resin tightly between the high-resistance anti-corona layer 5 and the inter-turn insulation 2, as well as between the polyester binding tape 6 and the inter-turn insulation 2 and the polyester fiber felt 8, reducing resin loss and enhancing the stability of the motor. The polyester binding tape 6 is purchased from Nanyang Xinmao Electrical Materials Co., Ltd., model YF0502, specification 0.2*25mm.

[0063] Comparative Example 1

[0064] The difference from Example 1 is that the main insulating layer 3 is different.

[0065] In this comparative example, the main insulation layer 3 is formed by wrapping high thermal conductivity mica tape in seven and a half layers, and then impregnating it with nanoparticle-modified vacuum pressure impregnation resin and curing it. The high thermal conductivity mica tape is a 0.14mm thick glass cloth-reinforced high thermal conductivity low adhesive mica tape produced by Suzhou Jufeng Electrical Insulation System Co., Ltd., model JF-5442-1HTC. The preparation method of nanoparticle-modified vacuum pressure impregnation resin is as described in Example 3 of ZL201210187846.1.

[0066] Comparative Example 2

[0067] The difference from Example 1 is that the main insulating layer 3 is different.

[0068] In this comparative example, the main insulation layer 3 is made of commercially available 0.14mm glass cloth reinforced low-adhesion mica tape wrapped in seven and a half layers, and cured with commercially available epoxy VPI impregnation resin and glass cloth reinforced low-adhesion mica tape; wherein, the glass cloth reinforced low-adhesion mica tape is JF-5442-1T mica tape produced by Suzhou Jufeng Electrical Insulation System Co., Ltd.; the epoxy VPI impregnation resin is JF-9956-3 epoxy VPI resin produced by Suzhou Jufeng Electrical Insulation System Co., Ltd.

[0069] Performance Experiment

[0070] The performance of the high-voltage motor stator coil insulation system in Example 1 and Comparative Examples 1 and 2 was tested, and the results are shown in Table 1. The thermal conductivity test method was based on GB / T 29313-2012 "Test Method for Thermal Conductivity of Electrical Insulation Materials"; the breakdown voltage strength and electrical aging life test methods were based on JB / T 12685-2016 "Technical Conditions for High-Voltage Motor Stator Coils"; and the evaluation standard for application processability was based on GB / T 15022.2017 "Resin-based Active Composites for Electrical Insulation Part 2: Test Methods" to test the storage stability and viscosity increase factor.

[0071] Table 1

[0072]

[0073] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A high-voltage motor stator coil insulation system, characterized in that: The high-voltage motor stator coil insulation system includes a straight section and an end section. The straight section and the end section respectively include a copper coil, inter-turn insulation covering the outside of the copper coil, a main insulation layer covering the outside of the inter-turn insulation, and a protective layer covering the outside of the main insulation layer. The main insulating layer is formed by curing mica tape and epoxy VPI resin. The epoxy VPI resin is made of nanoparticles, dispersant and epoxy resin. The raw materials of the epoxy VPI resin do not contain acid anhydride. The preparation method of the epoxy VPI resin includes first homogenizing and emulsifying the nanoparticles, the dispersant and the epoxy resin, and then grinding and dispersing them. The epoxy resin is epoxy-modified polyesterimide impregnating resin. The nanoparticles are aluminum oxide and silicon dioxide. The dispersant is BYK142 dispersant. The mass ratio of epoxy resin to nanoparticles to dispersant is 100:(15~25):(0.5~1.5).

2. The high-voltage motor stator coil insulation system according to claim 1, characterized in that: The particle size of the nanoparticles is 10~80nm.

3. The high-voltage motor stator coil insulation system according to claim 1 or 2, characterized in that: The mica tape is wrapped in a semi-overlapping manner, with 5 to 9 layers; and / or, The mica strip has a thickness of 0.1~0.2mm and a thermal conductivity ≥0.4W / (mK).

4. The high-voltage motor stator coil insulation system according to claim 1, characterized in that: The thermal conductivity of the main insulating layer is 0.35~0.5W / (mK).

5. The high-voltage motor stator coil insulation system according to claim 1, characterized in that: The rotation speed of the homogenization emulsification is controlled at 4000~6000 r / min, and the time is 1~2 h; the temperature of the system material is controlled to be below 60℃ during the homogenization emulsification and grinding dispersion. The nanoparticles dispersed in the system have a particle size of less than 80 nm.

6. The high-voltage motor stator coil insulation system according to claim 1, characterized in that: The inter-turn insulation is formed by wrapping 1 to 4 layers of polyester film-reinforced mica tape with a thickness of 0.03 to 0.09 mm in half-overlap; and / or, The thickness of the inter-turn insulation is 0.4~0.45mm.

7. The high-voltage motor stator coil insulation system according to claim 1, characterized in that: The straight section further includes a low-resistance anti-corona layer and a high-resistance anti-corona layer sequentially covering the outside of the main insulation layer. The protective layer is disposed outside the high-resistance anti-corona layer. The low-resistance anti-corona layer is formed by wrapping a low-resistance anti-corona tape with a thickness of 0.05~0.11mm in 1~2 layers of half-overlapping. The high-resistance anti-corona layer is formed by wrapping a high-resistance anti-corona tape with a thickness of 0.1~0.2mm in 1~2 layers of half-overlapping.

8. The high-voltage motor stator coil insulation system according to claim 1, characterized in that: The end also includes a stator coil lead arranged in parallel with the copper coil. The outside of the stator coil lead is successively covered with the inter-turn insulation and the polyester fiber felt. The main insulation layer is disposed outside the polyester fiber felt and the inter-turn insulation on the copper coil.

9. The high-voltage motor stator coil insulation system according to claim 7 or 8, characterized in that: The protective layer is formed by wrapping with polyester cable ties.

10. The high-voltage motor stator coil insulation system according to claim 1, characterized in that: The high-voltage motor is a high-voltage motor of 6kV or above.

11. A method for preparing a high-voltage motor stator coil insulation system as described in any one of claims 1 to 10, characterized in that: The preparation method includes the following preparation steps: (1) A polyester film reinforced mica tape is wound on the straight part of the stator coil of the high voltage motor, the copper coil at the end, and the stator coil lead at the end to form inter-turn insulation; (2) Mica tape is wrapped around the outside of the inter-turn insulation, and epoxy VPI resin is used to impregnate the mica tape and then cured to form the main insulation layer. The raw materials of the epoxy VPI resin do not contain acid anhydride. The preparation method of the epoxy VPI resin includes homogenizing and emulsifying nanoparticles, dispersant and epoxy resin, and then grinding and dispersing them. The curing temperature is controlled at 160~170℃ and the time is 8~13h. (3) A protective layer is wrapped around the outside of the main insulation layer.

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