WO2018206222A1 - Fil isolé d'un enroulement de stator comprenant une mise à la terre au moyen d'une couche conductrice - Google Patents

Fil isolé d'un enroulement de stator comprenant une mise à la terre au moyen d'une couche conductrice Download PDF

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Publication number
WO2018206222A1
WO2018206222A1 PCT/EP2018/059431 EP2018059431W WO2018206222A1 WO 2018206222 A1 WO2018206222 A1 WO 2018206222A1 EP 2018059431 W EP2018059431 W EP 2018059431W WO 2018206222 A1 WO2018206222 A1 WO 2018206222A1
Authority
WO
WIPO (PCT)
Prior art keywords
electrical machine
range
ohm
conductor
conductive layer
Prior art date
Application number
PCT/EP2018/059431
Other languages
English (en)
Inventor
Fredrik Sahlen
Göran Paulsson
Peter Isberg
Chau-Hon HO
Su Zhao
Original Assignee
Abb Schweiz Ag
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from EP17170762.3A external-priority patent/EP3402050A1/fr
Priority claimed from EP17170764.9A external-priority patent/EP3402051A1/fr
Application filed by Abb Schweiz Ag filed Critical Abb Schweiz Ag
Publication of WO2018206222A1 publication Critical patent/WO2018206222A1/fr

Links

Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K11/00—Structural association of dynamo-electric machines with electric components or with devices for shielding, monitoring or protection
    • H02K11/40—Structural association with grounding devices
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K3/00—Details of windings
    • H02K3/30—Windings characterised by the insulating material
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K15/00—Methods or apparatus specially adapted for manufacturing, assembling, maintaining or repairing of dynamo-electric machines
    • H02K15/04—Methods or apparatus specially adapted for manufacturing, assembling, maintaining or repairing of dynamo-electric machines of windings, prior to mounting into machines
    • H02K15/0435—Wound windings
    • H02K15/0442—Loop windings
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K3/00—Details of windings
    • H02K3/02—Windings characterised by the conductor material
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K3/00—Details of windings
    • H02K3/32—Windings characterised by the shape, form or construction of the insulation
    • H02K3/40—Windings characterised by the shape, form or construction of the insulation for high voltage, e.g. affording protection against corona discharges

Definitions

  • a conventional electrical machine 40 such as a low-voltage electrical motor, comprises a stator frame 21 with a grounding 50, a stator core 45 and a stator winding 10.
  • the electrical machine 40 further comprises a rotor 44 arranged within the stator core 45 in a rotatable manner by means of a rotor shaft 46 and bearings 43a, 43b.
  • the electrical machine 40 may be driven by means of a variable speed drive (VSD) .
  • VSD variable speed drive
  • a stator winding 10 of an electrical machine 40 can be either random-wound or form-wound. Random-wound stator windings 10 are less expensive to produce than form-wound since the former allows a higher degree of automation to be used during manufacturing.
  • the random-wound technology is therefore preferred over the form-wound one.
  • a limiting factor for using this technology is the relatively low partial discharge inception voltage (PDIV) of the resulting random-wound stator winding 10.
  • PDIV partial discharge inception voltage
  • form-wound stator windings 10 with a mica-based insulation material are often used in applications above 1000 V.
  • an alternative solution using random-wound stator windings 10 is to impregnate the stator winding 10 e.g. with a resin to remove substantially all the air surrounding the winding wires.
  • the former solution is more expensive, and the latter one does not work in practice in that there is no reliable method for removing the air surrounding tightly- packed winding wires to a sufficient extent.
  • random- wound stator windings 10 are many times impregnated with a resin, this is done for mechanical rather than electrical considerations.
  • none of the given solutions addresses the problem with bearing currents explained in the following.
  • bearing currents may occur due to fast-rising voltage pulses and high switching frequencies of the VSD, and they may cause bearing fluting, a rhythmic erosion pattern on the bearing races, which eventually leads to failure of the bearings 43a, 43b.
  • Bearing currents originate from a capacitive coupling 48 between the stator winding 10 and the rotor 44 of the electrical machine 40.
  • Figure 1 schematically shows bearing currents that may occur across the bearings 43a, 43b of the electrical machine 40. It is conventionally known to
  • One object of the invention is to provide an improved electrical machine comprising a random-wound stator winding with an increased resistance against partial discharges and a prevention of bearing currents.
  • the invention is based on the realization that by providing a winding wire with a conductive layer surrounding a conventional insulation layer, important prerequisites for both partial discharges and bearing currents are removed from the stator winding. This principally simple solution thereby addresses two significant problems with electrical machines, and enables increased voltage levels in random- wound stators with no additional measures required for managing bearing currents.
  • an electrical machine comprising at least one stator winding with a winding wire comprising a conductor.
  • An insulation layer surrounds the conductor along a
  • a conductive layer surrounds the insulation layer along a longitudinal
  • the conductive layer is grounded.
  • the stator winding is random-wound.
  • the conductive layer has a volume resistivity in the range of 0 - 10000 ohm cm, such as in the range of 0 - 1000 ohm cm, 0.1 - 1000 ohm cm, 1 - 1000 ohm cm, or in the range of 10 - 100 ohm cm.
  • the conductive layer is made of a semi-conductive material comprising a polymer matrix filled with conductive additives.
  • the conductive additives comprise one or more of: carbon based particles, metal particles and metal oxide particles.
  • the electrical machine further comprises a slot-liner made of an
  • the slot-liner material has a volume resistivity within a range of 1- 1000 ohm cm.
  • the at least one stator winding is impregnated with an impregnation resin comprising an electrically conductive additive.
  • the resin has a volume resistivity in the range of 1 - 10 000 ohm cm.
  • the electrical machine further comprises a variable speed drive.
  • the winding wire has a diameter or a maximum linear dimension within the range of 0.5 to 10 mm, such as within the range of 0.5 to 6 mm or within the range of 1 to 2 mm.
  • a wire end is provided with a field grading system.
  • the field grading system comprises one or more of: a shrinkage tube with linear or non-linear field grading properties, a paint with linear or non-linear field grading properties, and a geometric field grading.
  • the conductor consists of one piece of homogeneous conductor material.
  • the conductor material is substantially pure single metal such as copper or aluminium.
  • figure 1 shows a conventional electrical machine with an illustration of origin and routes for bearing currents
  • figure 2 shows a cross-sectional view a winding wire
  • figure 3 shows a flow chart showing steps of a method for manufacturing a winding wire according to one embodiment of the invention
  • figure 4 shows a winding wire constituting a part of a
  • figure 5 shows a part of a random-wound stator winding
  • figure 6a shows an electric field for a winding wire without a field grading system
  • figure 6b shows an electric field for a winding wire with a field grading system.
  • a winding wire 1 according to one embodiment of the invention comprises an electrical
  • the conductor 2 in the form of a metal wire.
  • the conductor 2 may consist e.g. of one piece of homogeneous copper or
  • the winding wire 1 may have a circular cross- section in order to minimize the electric field 6 across the insulation layer, and in order to facilitate the desired manufacturing of a stator winding 10 by using random-wound technology, but it is noted that the cross-section of the winding wire 1 may also have other shapes.
  • the cross-section may have a diameter within the range of 0.5 to 10 mm, such as within the range of 0.5 to 6 mm or within the range of 1 to 2 mm.
  • the cross-section may have a maximum linear dimension within the range of 0.5 to 10 mm, such as within the range of 0.5 to 6 mm or within the range of 1 to 2 mm.
  • random- wound refers to a respective winding wire 1 or a stator winding 10 that is suitable for random-wound technology or is a result of the same.
  • Random-wound technology in its turn implies that the winding wire 1 has suitable dimensions, flexibility and other properties such that it can be used in an automated process of manufacturing a stator winding 10 and a respective stator. In practice this means that the maximum diameter of the winding wire 1 is 10 mm or, in the case that the cross section of the winding wire 1 is not circular, the maximum linear dimension of the cross section is 10 mm .
  • the winding wire 1 comprises an insulation layer 3
  • the thickness of the insulation layer 3 may, for instance, be about 100 - 200 ⁇ . However, the insulation thickness may be selected and adapted in dependence on the applied voltage during operation.
  • the insulation layer 3 is made of a material with a high dielectric strength, i.e. the material should have a good ability to withstand the maximum electric field 6 (see figures 6a and 6b) within the
  • thermoplastic which has high thermo-mechanical properties, such as e.g.
  • PEEK polyetheretherketons
  • PEI polyetherimides
  • PES polyetherketons
  • PPS polyphenylensulfide
  • PPSU polyphenylensulphone
  • PSU polysulphone
  • PES polyethersulphone
  • PTFE polytetrafloroetylene
  • PVF polyvinylidenfloride
  • the dielectric strength of the insulation layer 3 may, for instance, be about 10 kV/mm and its thickness may, for instance, be about 100 ⁇ .
  • the winding wire 1 is provided with a conductive layer 4.
  • the conductive layer 4 may comprise a semi-conductive material, such as e.g. a polymer matrix filled with conductive additives, such as carbon based particles (e.g. carbon black, graphene, carbon nanotubes) or metal/metal oxide particles or other conductive materials.
  • the polymer matrix consists of the same polymer as the insulation layer 3 enabling good adhesion between the conductive layer 4 and the insulation layer 3.
  • the conductive layer 4 is arranged such as to surround the insulation layer 3 in the longitudinal direction thereof, the conductive layer 4 hence also surrounding the conductor 2.
  • the conductive layer 4 may, for instance, be in the range of 10-100 ⁇ thick, preferably about 25 - 50 ⁇ thick, and have a volume resistivity in the range of 0 - 10 000 ohm cm, such as in the range of 0 - 1000 ohm cm, 0.1 - 1000 ohm cm, 1 - 1000 ohm cm, or 10 - 100 ohm cm.
  • the conductivity of the conductive layer 4 enables proper grounding of the winding wire 1 and enclosure of the electric field 6 inside the insulation layer 3. The electric field 6 is thereby
  • the mechanical properties of the insulation layer 3 should preferably be such that the insulation layer 3 and the conductive layer 4 are kept intact even during mechanical stress e.g. when bending the winding wire 1 to form a stator winding 10.
  • To avoid defects in the winding wire 1 it is necessary to have good adhesion between the conductor 2 and the insulation layer 3 as well as between the insulation layer 3 and the conductive layer 4. This requirement can be achieved, for instance, by using the earlier mentioned materials PEEK and PEI.
  • the winding wire 1 may comprise an insulation system comprising two or more insulation layers 3.
  • material costs and the geometric dimensions of the winding wire 1 in use can be kept down when using a single insulation layer 3.
  • an insulation system comprising a single insulation layer 3 is used as an illustrative
  • Figure 3 shows a flow chart with steps of a method for manufacturing a winding wire 1 for a random-wound stator.
  • a conductor 2 is obtained.
  • the conductor 2 may, for instance, be produced by wire drawing, wherein a metal material is drawn through a series of dies of decreasing size.
  • the metal wire is produced by extrusion. It is noted that other metalworking processes may be used or the conductor 2 wire may be purchased from an external source.
  • step 32 the insulation layer 3 is applied on the
  • the method 30 for manufacturing the winding wire 1 according to the present invention preferably utilizes extrusion. This is preferred in order to ensure that the insulation layer 3 is free from defects.
  • the insulation layer 3 may be applied in other manners as well, e.g. by powder coating, provided that the requirement of a substantially defect free insulation layer 3 can be fulfilled.
  • step 33 the conductive layer 4 having a volume
  • the outer conductive layer 4 may be applied by coating, by painting or by spraying.
  • FIG 4 shows a winding wire 1 in the shape of a random- wound stator winding 10 according to one embodiment of the invention.
  • a stator winding 10 according to figure 3 can be used in many types of electrical machines 40, such as in traction motors.
  • a capacitive coupling 48 (see figure 1) between the stator winding 10 and the rotor 44 is effectively reduced to a high extent leading to reduced or omitted bearing currents.
  • Figure 5 illustrates a part of a random-wound stator core 45 comprising a stator winding 10 with a number of turns of the winding wire 1.
  • the individual turns of the winding wire 1 have random locations in respective stator slots 22.
  • the stator slots 22 are provided with slot liners 23 that mechanically protect the winding wire 1 from being damaged from contact with stator laminations.
  • slot liners 23 that mechanically protect the winding wire 1 from being damaged from contact with stator laminations.
  • the slot liners 23 according to one embodiment of the present invention can be much thinner than conventional slot liners 23, and do not need to be electrically insulating. Instead, the slot liners 23 according to the present invention may be made conductive to ensure appropriate grounding of the winding wire 1 to the stator core 45.
  • the volume resistivity of the slot liners 23 may e.g. be within the range of 1 to 1000 ohm cm in order to ensure appropriate grounding of the winding wire 1 without short circuiting the stator laminates.
  • the stator slots 22 may be impregnated with an electrically conductive resin after inserting the stator winding 10. This is done for securing the grounding and mechanical stability of the winding wire 1.
  • the electrically conductive resin also promotes the thermal conductivity of the resin and hence a better cooling of the winding can be achieved.
  • the resin may have a volume resistivity in the range of 1 - 10 000 ohm cm.
  • the conductive layer 4 of a winding wire 1 acts as a screen, encapsulating an electric field 6 (illustrated by means of equipotential lines) , and prevents in that way partial discharges in the winding wire 1.
  • wire ends 7 of the winding wire 1 need to be connected to respective electrical terminals in order to form an electrical circuit. To enable this, a certain length of the conductive layer 4 and the insulation layer 3 need to be removed at the wire ends 7.
  • each wire end 7 is provided with a field grading system 5.
  • Figure 6b illustrates an electric field 6 in the case where the wire end 7 is provided with a field grading system 5.
  • the field grading system 5 is applied on the insulation layer 3 at a section where the conductive layer 4 is
  • the wire end 7 may
  • the field grading system 5 may comprise a shrinkage tube or a paint with field grading properties at the wire ends 7.
  • the shrinkage tube and the paint may have either linear or non-linear field grading properties. Alternatively,
  • a field grading paint may be combined with a geometric field

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Insulation, Fastening Of Motor, Generator Windings (AREA)

Abstract

La présente invention concerne une machine électrique (40) comprenant au moins un enroulement de stator (10) pourvu d'un fil d'enroulement (1) comprenant un conducteur (2) et une couche d'isolation (3) entourant le conducteur (2) dans son sens longitudinal. Une couche conductrice (4) entoure la couche d'isolation (3) dans son sens longitudinal et est mise à la terre. Le fil d'enroulement (1) comprenant une couche conductrice (4) entourant une couche d'isolation classique (3) permet d'éliminer de l'enroulement de stator (10) des conditions préalables importantes en ce qui concerne les courants porteurs et les décharges partielles, ce qui permet d'augmenter les niveaux de tension dans les enroulements du stator sans autres mesures supplémentaires nécessaires à la déviation des courants porteurs.
PCT/EP2018/059431 2017-05-12 2018-04-12 Fil isolé d'un enroulement de stator comprenant une mise à la terre au moyen d'une couche conductrice WO2018206222A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
EP17170764.9 2017-05-12
EP17170762.3A EP3402050A1 (fr) 2017-05-12 2017-05-12 Fil isolé d'une bobine pour un stator à fils jetés
EP17170764.9A EP3402051A1 (fr) 2017-05-12 2017-05-12 Machine électrique comprenant une couche semi-conductrice sur le bobinage pour améliorer la mise à la terre
EP17170762.3 2017-05-12

Publications (1)

Publication Number Publication Date
WO2018206222A1 true WO2018206222A1 (fr) 2018-11-15

Family

ID=61899318

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2018/059431 WO2018206222A1 (fr) 2017-05-12 2018-04-12 Fil isolé d'un enroulement de stator comprenant une mise à la terre au moyen d'une couche conductrice

Country Status (1)

Country Link
WO (1) WO2018206222A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114256995A (zh) * 2021-12-27 2022-03-29 同济大学 一种长定子磁浮系统直线电机定子模块

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1600239A (en) * 1977-11-28 1981-10-14 Northern Eng Ind Winding carrying laminated cores in electromagnetic machines
EP1975949A1 (fr) * 2007-03-30 2008-10-01 Abb Research Ltd. Matériau de calibrage de champs
EP2469687A2 (fr) * 2010-12-23 2012-06-27 General Electric Company Structure de moteur électrique permettant de minimiser l'interférence électromagnétique
DE102011075425A1 (de) * 2011-05-06 2012-11-08 Siemens Aktiengesellschaft Verfahren zum Herstellen eines elektrischen Isolationssystems für eine elektrische Maschine
WO2012162435A2 (fr) * 2011-05-23 2012-11-29 Active Power, Inc. Système d'isolation pour la prévention d'une décharge par effet couronne
DE102011106480A1 (de) * 2011-06-14 2012-12-20 Voith Patent Gmbh Asynchronmaschine
US20150243410A1 (en) * 2014-02-25 2015-08-27 Essex Group, Inc. Insulated Winding Wire

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1600239A (en) * 1977-11-28 1981-10-14 Northern Eng Ind Winding carrying laminated cores in electromagnetic machines
EP1975949A1 (fr) * 2007-03-30 2008-10-01 Abb Research Ltd. Matériau de calibrage de champs
EP2469687A2 (fr) * 2010-12-23 2012-06-27 General Electric Company Structure de moteur électrique permettant de minimiser l'interférence électromagnétique
DE102011075425A1 (de) * 2011-05-06 2012-11-08 Siemens Aktiengesellschaft Verfahren zum Herstellen eines elektrischen Isolationssystems für eine elektrische Maschine
WO2012162435A2 (fr) * 2011-05-23 2012-11-29 Active Power, Inc. Système d'isolation pour la prévention d'une décharge par effet couronne
DE102011106480A1 (de) * 2011-06-14 2012-12-20 Voith Patent Gmbh Asynchronmaschine
US20150243410A1 (en) * 2014-02-25 2015-08-27 Essex Group, Inc. Insulated Winding Wire

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114256995A (zh) * 2021-12-27 2022-03-29 同济大学 一种长定子磁浮系统直线电机定子模块

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