DESC:STATOR WINDING LAYOUT FOR A BRUSHLESS DIRECT CURRENT
(BLDC) MOTOR IN ELECTRIC VEHICLE
FIELD OF INVENTION:
[001] The present invention generally relates to motor winding and more
particularly relates to 5 winding process in a brushless DC motor of electric vehicle.
BACKGROUND AND PRIOR ART AND PROBLEM IN PRIOR ART:
[002] Disadvantages of Concentric Winding:
[003] Increased Manufacturing Complexity: Concentric winding requires careful
placement of coils within the stator slots to ensure proper alignment and optimal
10 performance. This complexity can lead to higher manufacturing costs and
potential production challenges.
[004] Limited Cooling: Concentric winding can restrict airflow within the motor,
limiting the effectiveness of cooling. This limitation may result in higher
operating temperatures and reduced overall efficiency and lifespan of the motor.
15 [005] Potential for Increased Eddy Current Losses: The close proximity of
windings in a concentric configuration can lead to increased eddy current losses,
especially at higher speeds or when operating at high frequencies. These losses
contribute to energy inefficiency and may necessitate additional measures to
mitigate their impact.
20 [006] Disadvantages of Distributed Winding:
[007] Increased Copper Losses: Distributed winding typically requires more
copper wire compared to concentrated winding configurations. This increased
copper usage can lead to higher copper losses, especially at higher currents,
resulting in reduced efficiency.
25 [008] Complexity of Manufacturing and Assembly: Distributed winding
configurations may require more intricate manufacturing processes and assembly
techniques due to the need for precise placement of multiple coils. This
2
complexity can result in higher production costs and potential challenges in
maintaining consistency and quality.
[009] Higher Inrush Currents: Distributed winding configurations may exhibit
higher inrush currents during startup compared to concentrated winding
configurations. This can 5 pose challenges in terms of power supply design and may
require additional components to mitigate the effects of inrush currents.
[0010] Overall, while both concentric and distributed winding configurations
offer advantages in certain applications, they also have their respective drawbacks
that need to be carefully considered during the design and selection process of
10 BLDC motors. Factors such as cost, efficiency, cooling requirements, and
manufacturing complexity play crucial roles in determining the most suitable
winding configuration for a particular application.
[0011] These and other objects and advantages of the present subject matter will
be apparent to a person skilled in the art after consideration of the following
15 detailed description taken into consideration with accompanying drawings in
which preferred embodiments of the present subject matter are illustrated.
SUMMARY OF THE INVENTION
[0012] This summary is provided to introduce a selection of concepts, in a
simplified format, that are further described in the detailed description of the
20 invention. This summary is neither intended to identify key or essential inventive
concepts of the invention nor is it intended for determining the scope of the
invention.
[0013] In an aspect of the present invention, a system for .
[0014] In another aspect of the present invention, a method for .
25 [0015] To further clarify the advantages and features of the present invention, a
more particular description of the invention will be rendered by reference to
specific embodiments thereof, which are illustrated in the appended drawings. It is
appreciated that these drawings depict only typical embodiments of the invention
and are therefore not to be considered limiting of its scope. The invention will be
3
described and explained with additional specificity and detail with the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] It is to be noted, however, that the appended drawings illustrate only
typical embodiments of the present subject 5 matter and are therefore not to be
considered for limiting of its scope, for the invention may admit to other equally
effective embodiments. The detailed description is described with reference to the
accompanying figures. Some embodiments of system or methods or structure in
accordance with embodiments of the present subject matter are now described, by
10 way of example, and with reference to the accompanying figures, in which:
[0017] Fig. 1 illustrates a perspective view of a stator winding layout in a
brushless direct current (BLDC) motor of an electric vehicle, according to
embodiments of the present invention;
[0018] Fig. 2 illustrates another perspective view of the stator winding layout in
15 the BLDC motor of the electric vehicle, according to embodiments of the present
invention; and
[0019] Fig. 3 illustrates an exemplary table detailing stator slot view, according to
embodiments of the present invention.
[0020] The figures depict embodiments of the present subject matter for the
20 purposes of illustration only. A person skilled in the art will easily recognize from
the following description that alternative embodiments of the structures and
methods illustrated herein may be employed without departing from the principles
of the disclosure described herein.
DESCRIPTION OF THE PREFERRED EMBODIMENTS:
25 [0021] In the following detailed description of the disclosure, reference is made to
the accompanying drawings that show, by way of illustration, specific
embodiments in which the disclosure may be practiced. These embodiments are
described in sufficient detail to enable those skilled in the art to practice the
disclosure. It should be understood that the various embodiments of the present
4
disclosure are different but not necessarily mutually exclusive. For example, the
specific features, structures, and characteristics described herein in connection
with one embodiment can be implemented in other embodiments without
departing from the spirit and scope of the present disclosure. It should also be
understood that the location 5 or arrangement of individual components in each
disclosed embodiment may be changed without departing from the spirit and
scope of the present disclosure. For this reason, the following detailed description
should not be construed as limiting, and the scope of the present disclosure is
defined by the scope of claims, and is appropriately determined based on the
10 entire scope equivalent to the contents of the claims. Interpreted. In the drawings,
like reference numbers can indicate identical or similar functions in various ways.
[0022] While the embodiments of the disclosure are subject to various
modifications and alternative forms, specific embodiment thereof have been
shown by way of example in the figures and will be described below. It should be
15 understood, however, that it is not intended to limit the disclosure to the particular
forms disclosed, but on the contrary, the disclosure is to cover all modifications,
equivalents, and alternative falling within the scope of the disclosure.
[0023] The terms “comprises”, “comprising”, or any other variations thereof used
in the disclosure, are intended to cover a non-exclusive inclusion, such that a
20 device, system, assembly that comprises a list of components does not include
only those components but may include other components not expressly listed or
inherent to such system, or assembly, or device. In other words, one or more
elements in a system or device proceeded by “comprises… a” does not, without
more constraints, preclude the existence of other elements or additional elements
25 in the system or device.
[0024] The data processing system includes one or more data processing devices
that perform the processes of various embodiments of the present invention. The
term “data processing device” or “data processor” is intended to include any data
processing device, including, for example, a Central Processing Unit, desktop
30 computer, laptop, information terminals, digital cameras, mobile phones or other
5
devices or components that process data, manage data, and handle data, electrical,
magnetic, optical, biological components. It does not matter whether it is
implemented in any other way.
[0025] The processor accessible memory system includes one or more processor
accessible memories configured 5 to store information, described herein.
Information necessary to execute the processes of the various embodiments of the
present invention. Processor accessible memory system may be a distributed
processor accessible memory system including a plurality of processor accessible
memories communicatively coupled to data processing system via a plurality of
10 computers and / or devices. On the other hand, the processor accessible memory
system need not be a distributed processor accessible memory, and thus is one or
more processor accessible memories located in a single data processor or device.
[0026] The phrase “processor accessible memory” is intended to include
volatile, non-volatile electronic, magnetic, optical or any other processor
15 accessible data storage device, such as, but not limited to, a register, floppy It may
be a disk, a hard disk, a Compact Disc, a DVD, a flash memory, a ROM, or a
RAM.
[0027] The phrase “communicatively connected” is intended to include any type
of connection between devices, method, data processors or programs, whether
20 wireless or wired, with which data may be communicated. Furthermore, the
phrase “communicatively connected” refers to connections between devices or
programs within a single data processor, connections between devices or
programs located in different data processors, and data processors. Includes
connections between devices that are not deployed. In this regard, although the
25 processor accessible memory system is shown separate from the data processing
system, those skilled in the art will understand that the processor accessible
memory system may be wholly or partially in the data processing system. It will
be appreciated that may be stored in Further in this regard, although the peripheral
system and the user interface system are shown separately from the data
30 processing system, those skilled in the art will recognize that one or both of these
6
systems may be used in whole or in part for data processing. It will be appreciated
that it may be stored in the system.
[0028] In an embodiment, the present disclosure provides an innovative stator
winding layout for a Brushless Direct Current (BLDC) motor specifically
designed for electric vehicles 5 (EVs). This stator winding layout aims to enhance
efficiency, reliability, and manufacturability of an electric motor of the EV by
introducing a structured and optimized winding configuration.
[0029] In an embodiment, the stator winding layout within the BLDC motor,
which is a critical component responsible for generating the magnetic field that
10 interacts with the rotor to produce motion.
[0030] In an embodiment, for stator winding configuration, coils are arranged
per Pole. For example, each pole of the BLDC motor has two coils. Alternatively,
a configuration with one coil per pole is also used. Each coil comprises 4 turns of
wire. Each coil consists of 22 strands of wire connected in parallel. This parallel
15 arrangement reduces the overall resistance and enhances current-carrying
capacity. Each coil spans one slot in the stator, meaning that each coil occupies a
single slot position within the stator's slot arrangement.
[0031] In an embodiment, the electric motor operates on a three-phase system,
requiring 18 Coils per Phase. For each of the three phases (U, V, W), 18 coils are
20 manufactured. This results in a total of 54 coils for all three phases combined.
[0032] In an embodiment, a high-strength, flame-resistant paper used for
insulation purposes within the motor. The Slot Liner may act as an insulation
barrier between the magnet, wire, and stator lamination, preventing electrical
shorts and ensuring safe operation. An insulation barrier inserted between coils of
25 different phases within the same slot to prevent electrical interference and crossphase
contamination. A component that holds the coils securely within the slot,
ensuring that they remain in place during motor operation and vibrations.
[0033] In an embodiment, the winding process includes, inserting the prepared
slot liners into the stator stack as explained in Figure 1-2, thus advantageously
7
ensuring precise placement for effective insulation and separation of phases.
Further, 18 coils are inserted one by one into each stator slot corresponding to a
single phase. Thus, advantageously ensuring that each coil is correctly positioned
and secured within the slot. Further, each slot accommodates coils from different
phases on its two sides. Further, left 5 side may be occupied by a coil from one
phase e.g., Phase U. Further, right side may be occupied by a coil from another
phase (e.g., Phase V). Advantageously, this arrangement ensures that each slot
contains coils from two distinct phases, maintaining phase separation and
minimizing electromagnetic interference. Further, the lead wires connected to the
10 magnet wire (phase termination) are insulated using Polytetrafluoroethylene
(PTFE), which offers excellent thermal and chemical resistance. The PTFEinsulated
lead wires are joined to the magnet wire phase termination using a
brazing process, which involves melting and flowing a filler metal into the joint to
create a strong, conductive bond. Further, a first layer of brazed joints are
15 insulated with a glass cloth tube, providing robust protection against electrical
shorts and environmental factors. Over the glass cloth tube, shrinkable sleeves are
applied to ensure a secure and tamper-proof insulation layer, enhancing the
durability and safety of the electrical connections.
[0034] In an embodiment, all inter-winding joints necessary for forming the U, V,
20 and W lead wires are consolidated and formed on one side of the end winding.
[0035] In an advantageous aspect of the present disclosure:
[0036] Shorter End Winding Height: By centralizing the inter-winding joints, the
overall height of the end winding is reduced. This compact design minimizes
space usage and contributes to a more streamlined motor profile.
25 [0037] Simplified Manufacturing: Consolidating the joints on one side simplifies
the manufacturing process, reducing the complexity and potential for errors during
assembly.
[0038]
8
[0039] Fig. 1: Likely presents an overall view or schematic of the BLDC motor,
highlighting the stator and rotor components.
[0040] Fig. 2: Provides another perspective view of the stator winding layout,
illustrating the arrangement of coils, phase separation, and slot components.
[0041] Fig. 3: Displays 5 an exemplary table detailing the stator slot view,
specifying the dimensions, coil placements, and component arrangements within
each slot.
[0042] In an embodiment, the stator winding layout offers several significant
benefits for BLDC motors in EVs such as:
10 The use of parallel strands in each coil lowers the overall resistance, improving
current flow and motor efficiency.
Insulating barriers prevent electrical interference between phases, ensuring stable
and reliable motor operation.
Slot wedges and precise winding techniques ensure that coils remain firmly in
15 place, reducing the risk of movement or vibration-induced damage.
Using standardized Nomex paper components for slot liners, phase separators, and
slot wedges streamlines the manufacturing process.
Centralizing inter-winding joints simplifies assembly, reduces manufacturing
time, and lowers the likelihood of defects.
20 Multiple layers of insulation (Nomex paper, glass cloth tube, shrinkable sleeves)
protect against electrical shorts and environmental degradation.
Reduced end winding height minimizes potential points of mechanical stress and
improves overall motor reliability.
The stator winding configuration may be adapted for different motor sizes and
25 specifications by adjusting the number of coils per phase and their arrangement
within the slots.
9
[0043] Thus the present disclosure provides the stator winding layout for BLDC
motors in electric vehicles, emphasizing efficiency, reliability, and
manufacturability. By employing a structured approach to coil configuration, slot
preparation, winding processes, electrical connections, and end winding design,
the invention ensures 5 optimal motor performance and longevity. These
advancements contribute to the overall effectiveness of electric vehicles,
enhancing their operational capabilities and reducing maintenance requirements.
[0044] Fig. 1 illustrates a perspective view of a stator winding layout in a
brushless direct current (BLDC) motor of an electric vehicle, according to
10 embodiments of the present invention. Fig. 2 illustrates another perspective view
of the stator winding layout in the BLDC motor of the electric vehicle, according
to embodiments of the present invention. Fig. 3 illustrates an exemplary table
detailing stator slot view, according to embodiments of the present invention.
[0045] Referring to Fig.1, Fig.2, and Fig. 3, Stator winding consists of 2 coils per
15 pole to create one pole and one coil per pole to create one pole, each coil will have
4 turns and 22 strands in parallel. The span of each coil is 01 slot.
[0046] In an example, 18 such coils have to be made for one phase of three phase
systems, totally 54 coils have to be made for three phases.
[0047] Further, marking and cutting of Nomex paper for slot liner, phase
20 separator and slot wedge as per the slot profile. Slot liner is an insulation barrier
between the Magnet, wire and stator lamination. Phase separator is an insulation
barrier inserted in the slot between the coils of different phases. Slot wedge helps
to hold the coils within the slot.
[0048] Furthermore, insert slot liners into the stator stack, as per the winding
25 drawing 18 coils are inserted turn by turn into the stator slot consisting of one
phase. Each slot will have two sides of the coils of different phases. One side of a
coil of one phase of one three phase system will occupy the left side of the slot
and the right side will be occupied by one side of the coil of another phase of the
same three phase system.
10
[0049] Furthermore, the PTFE Insulated lead wires connected to the magnet wire
phase termination shall be joined by brazing process and the brazed joints are
insulated with the first layer of glass cloth tube and inserted shrinkable sleeves.
[0050] Furthermore, all the inter windings joints for forming U, V, W lead wires
are formed at one side of 5 the end winding. As such, the achieved end winding has
a shorter height.
Table (1): Stator winding details
[0051] Advantages of Fractional Winding over conventional Concentric &
10 Distributed Winding are as follows:
1. CPP ( Coils per Pitch/Phase) is 0.375 in Fractional Winding compared to 02 in
concentric & distributed winding.
2. Fractional slot winding has better motor performance compared to concentric
and distributed winding.
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3. Slot fill factor is improved, hence the winding resistance is reduced and slot
thermal conductivity is improved.
4. Fractional slot winding has a shortened end thus reducing overall length. The
span of coil for Fractional Winding is 01 as compared to concentric/distributed
winding is minimum 02. Due to this 5 end winding length will be more compared to
fraction slot winding.
5. High power density and high efficiency due to reduced copper loss.
6. Low Cogging Torque due to the location of stator winding at different angular
positions with respect to the rotor pole.
10 7. Higher the number of Poles is Higher the Torque. As compared to
Concentric/distributed winding, Fractional winding will have more poles in a 12
inch motor by creating Physical 12 poles and Virtual 36 poles based on the
direction of current flow in winding.
[0052] Although the foregoing description has described the disclosure in
15 connection with specific components, various embodiments, and specific matters
such as drawings, these have been presented merely to facilitate understanding of
the present disclosure. The disclosure is not limited to the embodiments. It will be
apparent to those skilled in the art based on the above description that the above
embodiments can be modified and changed in various ways.
20 [0053] For this reason, the intention of the present disclosure should not be
limited to the above-described embodiment, but the scope of the claims and the
points modified uniformly or equally are considered to be included in the scope of
the present disclosure.
[0054] It will be understood by those within the art that, in general, terms used
25 herein, and especially in the appended claims (e.g., bodies of the appended
claims) are generally intended as “open” terms (e.g., the term “including” should
be interpreted as “including but not limited to,” the term “having” should be
interpreted as “having at least,” the term “includes” should be interpreted as
“includes but is not limited to,” etc.). It will be further understood by those within
12
the art that if a specific number of an introduced claim recitation is intended, such
an intent will be explicitly recited in the claim, and in the absence of such
recitation no such intent is present. For example, as an aid to understanding, the
following appended claims may contain usage of the introductory phrases “at least
one” and “one or more” to introduce claim 5 recitations. However, the use of such
phrases should not be construed to imply that the introduction of a claim recitation
by the indefinite articles “a” or “an” limits any particular claim containing such
introduced claim recitation to inventions containing only one such recitation, even
when the same claim includes the introductory phrases “one or more” or “at least
10 one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should
typically be interpreted to mean “at least one” or “one or more”); the same holds
true for the use of definite articles used to introduce claim recitations. In addition,
even if a specific number of an introduced claim recitation is explicitly recited,
those skilled in the art will recognize that such recitation should typically be
15 interpreted to mean at least the recited number (e.g., the bare recitation of “two
recitations,” without other modifiers, typically means at least two recitations, or
two or more recitations). Furthermore, in those instances where a convention
analogous to “at least one of A, B, and C, etc.” is used, in general such a
construction is intended in the sense one having skill in the art would understand
20 the convention (e.g., “a system having at least one of A, B, and C” would include
but not be limited to systems that have A alone, B alone, C alone, A and B
together, A and C together, B and C together, and/or A, B, and C together, etc.).
In those instances, where a convention analogous to “at least one of A, B, or C,
etc.” is used, in general such a construction is intended in the sense one having
25 skill in the art would understand the convention (e.g., “a system having at least
one of A, B, or C” would include but not be limited to systems that have A alone,
B alone, C alone, A and B together, A and C together, B and C together, and/or A,
B, and C together, etc.). It will be further understood by those within the art that
virtually any disjunctive word and/or phrase presenting two or more alternative
30 terms, whether in the description, claims, or drawings, should be understood to
contemplate the possibilities of including one of the terms, either of the terms, or
13
both terms. For example, the phrase “A or B” will be understood to include the
possibilities of “A” or “B” or “A and B.”
[0055] It will be further appreciated that functions or structures of a plurality of
components or steps may be combined into a single component or step, or the
functions or structures of 5 one-step or component may be split among plural steps
or components. The present invention contemplates all of these combinations.
Unless stated otherwise, dimensions and geometries of the various structures
depicted herein are not intended to be restrictive of the invention, and other
dimensions or geometries are possible. In addition, while a feature of the present
10 invention may have been described in the context of only one of the illustrated
embodiments, such feature may be combined with one or more other features of
other embodiments, for any given application. It will also be appreciated from the
above that the fabrication of the unique structures herein and the operation thereof
also constitute methods in accordance with the present invention. The present
15 invention also encompasses intermediate and end products resulting from the
practice of the methods herein. The use of “comprising” or “including” also
contemplates embodiments that “consist essentially of” or “consist of” the recited
feature. ,CLAIMS:WE CLAIM:
1. A stator winding layout for a brushless direct current (BLDC) motor,
comprising:
a plurality of coils, wherein each pole of the motor comprises at least
two coils, and each coil 5 is formed with four turns of wire and 22 strands in
parallel;
wherein each coil spans a single stator slot, and the winding layout
includes 18 coils per phase for a three-phase system, resulting in a total of
54 coils;
10 wherein each stator slot accommodates two coil sides, with one side
belonging to a coil of one phase and the other side belonging to a coil of a
different phase, thereby ensuring balanced electromagnetic force
distribution within the motor.
2. The stator winding layout as claimed in claim 1, comprising:
15 a stator stack configured with slot liners made from Nomex paper,
serving as insulation barriers between the stator lamination, magnet, and
winding wires;
phase separators inserted within the stator slots between coils of
different phases, providing insulation and preventing electrical short
20 circuits; and
slot wedges positioned within the stator slots to secure the coils,
ensuring the stability and proper alignment of the windings during motor
operation.
3. The stator winding layout as claimed in claim 1, wherein the coils are
25 inserted turn by turn into the stator slots, ensuring even distribution of
electromagnetic forces and minimizing vibrations during motor operation.
15
4. The stator winding layout as claimed in claim 1, wherein the slot liners,
phase separators, and slot wedges are designed to withstand high
temperatures and mechanical stresses, thereby enhancing the durability
5 and longevity of the motor.
5. The stator winding layout as claimed in claim 1, wherein the slot liners are
formed from a non-conductive, heat-resistant material that prevents
electrical short circuits and maintains the integrity of the winding during
high-temperature operation.
10 6. The stator winding layout as claimed in claim 1, wherein the winding
wires are made from a conductive material that is resistant to oxidation
and wear, thereby improving the overall efficiency and lifespan of the
motor.
7. The stator winding layout as claimed in claim 1, wherein the slot wedges
15 are designed to provide mechanical support to the coils during high-speed
operation, thereby reducing the likelihood of coil displacement or damage.
8. A method of assembling a stator winding layout in a brushless direct
current (BLDC) motor, the method comprising:
inserting slot liners into the stator stack;
20 sequentially inserting 18 coils per phase into the stator slots, with each
coil comprising four turns and 22 strands in parallel, such that each slot
accommodates coil sides from different phases;
connecting PTFE insulated lead wires to the phase terminations of the
magnet wire through a brazing process, and subsequently insulating the
25 brazed joints with glass cloth tubing and shrinkable sleeves; and
16
forming inter-winding joints for the U, V, and W lead wires at one side
of the end winding, resulting in a shorter end winding height.
9. The method as claimed in claim 8, comprising the step of forming a matrix
of inter-winding joints on one side of the stator, thereby reducing the
overall height 5 of the end winding and contributing to a more compact
motor design.
10. The method as claimed in claim 8, wherein the stator slots are designed to
accommodate two sides of coils from different phases, ensuring that the
magnetic flux within the motor is evenly distributed across all phases.
10 12. The method as claimed in claim 8, further comprising the step of testing
the insulation integrity of the brazed joints after the application of glass
cloth tubing and shrinkable sleeves, to ensure that the joints are properly
insulated and protected from environmental factors.
13. A method of operating a brushless direct current (BLDC) motor with the
15 stator winding layout as claimed in claim 1, comprising:
applying an alternating current to the stator winding layout to generate
a rotating magnetic field;
monitoring the temperature and electrical resistance of the winding
layout during operation to ensure optimal performance; and
20 adjusting the input current based on the detected parameters to
maintain the efficiency and safety of the motor.