Description:“MULTI-PHASE ELECTRICAL MACHINES”

FIELD OF THE INVENTION:

[001] The present invention is related to the multi-phase electrical machines, specifically, to the placement of windings and connection rings in the multi-phase machine.

[002] Multi-phase electrical machines have got many applications which include electric ship propulsion, locomotive traction, electric vehicles and high power industry applications due to enhanced torque and fault tolerant capability. The more the number of phases, the more will be the advantages of multi-phase electrical machine w.r.t fault tolerance, redundancy and availability. However, as the number of phases of electrical machine increases, placement of connection rings, accessibility, maintenance and structural stability becomes challenging. Hence, the placement of windings in the stator core and connection rings beside the stator core in the multi-phase machine plays vital role to overcome the above challenges.

BACKGROUND OF THE INVENTION:

[003] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.

[004] The conventional electric machines operate either as motors or generators, while some machines operate both as motor and generators. Conventional electric machines typically include a rotating part referred to as rotor and a stationary part referred to as a stator.

[005] The conventional electric machines usually have a drawback of limited compactness. Moreover, the conventional designs of the electric machine provide low torque and low fault tolerant capability. Hence, there is a requirement of an electric machine with a multi-phase winding arrangement for increased torque, decreased torque ripple and high fault tolerant capability.

[006] In conventional multi-phase winding arrangements of electrical machine, the coils are placed in stator core such that all the leads are taken out from one side of the machine and are terminated/brazed to connection rings placed on one side of the stator core which makes the accessibility of connection rings and maintenance difficult as the number of connection rings increases with number of phases. The conventional placement of connection rings in the multi-phase electrical machine also leads the structure to stability issues in multi-phase machines with higher number of phases. Hence, there is a need for an electric machine with an improved design and configurations.

PRIOR ART

[007] Reference may be made to the below known arts:

[008] In patent no. US9774290B2A, a multi-phase multi-pole electric machine attached to a vehicle has been invented. The multi-phase multi-pole electric machine includes rotor, stator with five phase windings, machine controller, and torque sensors. The machine controller controls the flow of current. The torque sensors sense the torque exerted by the vehicle and transmits the information to the machine controller. The machine controller provides four degree of control through injection of five phase currents and thus providing higher torque.

[009] In patent no. WO9418741A1, a modular design of multiphase electrical machine has been disclosed. Known multiphase electric machines have conductor wires which do not sufficiently utilize the space available in the grooves and winding head, or which are costly to produce. Besides a good utilization of the available space, the length of the conductors in the winding heads should be kept short in order to obtain high power and energy densities, and the number of different conductor designs should be minimized in order to reduce production costs.

[0010] According to the invention, the electric machine consists of several electric pole units which have each a small number of phases and poles with alternating polarity in the direction of displacement. The electric pole units are located next to each other in the air gap and are mutually offset by a fraction of a pole pitch with respect to the rotor poles. Their meandering rectangular conductor wires extend in layers parallel to the air gap. In mono-phase electric pole units, the conductor insulation is designed for only a fraction of the terminal voltage.

[0011] In patent no. WO2016201405A1, a modulation scheme for multiphase electrical machine has been invented. An electrical power system for a six-phase electric motor having a first set of three-phase windings and a second set of three-phase windings. A first pulse width modulator operates at a conversion frequency and at a first phase which converts a DC power source to an alternating current to power the motor. The first pulse width modulator is electrically connected to the first set of three-phase windings. Similarly, a second pulse width modulator also operates at the same conversion frequency and at a second phase which converts the DC power to alternating current to power the second set of three-phase windings. The first and second phases of the first and second pulse width modulators are offset between 80-100 degrees.

[0012] In patent no. US912144, a multiphase electric induction motor has been introduced. This invention relates to multiphase electric induction motors, and has for its object to enable the speed of such motors to be altered to different values in an improved manner by an arrangement of a simple and effective character in which, as has already been proposed in other regulating schemes, the primary element is caused to rotate with respect to the secondary.

[0013] In patent no. US7579738B2, a multi-phase electrical motor for use in a wheel has been proposed. The invention relates to a rotary multi-phase electrical motor wherein stator teeth corresponding to one same phase are grouped on a distinct and magnetically isolated stator section. The number of teeth per stator section is an odd number of a value of at least three and the difference between the total number of stator teeth and the number of rotor permanent magnet poles is one. The teeth are preferably equidistantly distributed along the stator. The invention also relates to a wheel motor using the rotary multi-phase electrical motor described above.

[0014] None of the above serve the purpose of the invention, for which it is designed.

OBJECTS OF THE INVENTION:

[0015] Primary objective of the invention is to develop a multiphase machine with high structural stability.

[0016] Secondary objective of the invention is to place the coils in the stator core of the machine optimally such that size of the machine can be optimized.

[0017] One more objective of the invention is to identify optimal placement of connection rings of multiphase machine.

[0018] Still another objective of the invention is to increase the ease of accessibility and ease of maintenance of connection rings in the multiphase machine.

[0019] One more objective of the invention is to identify optimal placement of bus bars in the terminal box of multiphase machine.

[0020] These and other objects and advantages of the present invention will be apparent to those skilled in the art after a consideration of the following detailed description taken in conjunction with the accompanying drawings in which a preferred form of the present invention is illustrated.

SUMMARY OF THE INVENTION:

[0021] One or more drawbacks of conventional systems and process are overcome, and additional advantages are provided through the apparatus/composition and a method as claimed in the present disclosure. Additional features and advantages are realized through the technicalities of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered to be part of the claimed disclosure.

[0022] The main objective of the present invention is to optimally arrange the connection rings belonging to different phases of multiphase machine in order to achieve the structural stability, ease of accessibility and maintenance of connection rings.

[0023] In the present invention, a multiphase machine with optimal placement of connection rings is proposed by placing few connection rings on one side of stator core and the remaining connection rings on the other side of the stator core unlike in conventional multiphase machine wherein all connection rings are placed on side of the stator core.

[0024] Accordingly, bus bars in the terminal box are segregated into two groups in line with the number of connection rings placed at two ends of the stator core and arranged in such a way that each group of bus bars is close to its respective connection rings.

[0025] In the present invention of multiphase machine with optimal placement of connection rings, ending bars of only few winding sets/few phases are connected to neutral rings on one side while starting bars of remaining winding sets/remaining phases are connected to neutral rings on the other side unlike in conventional multiphase machine wherein all ending bars are connected to neutral rings on one side only.

[0026] Various objects, features, aspects, and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.

[0027] It is to be understood that the aspects and embodiments of the disclosure described above may be used in any combination with each other. Several of the aspects and embodiments may be combined to form a further embodiment of the disclosure.

[0028] The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS:

[0029] The illustrated embodiments of the subject matter will be best understood by reference to the drawings, wherein like parts are designated by like numerals throughout. The following description is intended only by way of example, and simply illustrates certain selected embodiments of devices, systems, and processes that are consistent with the subject matter as claimed herein, wherein:-

[0030] Figure 1 shows: Existing placement of windings and connection rings.

[0031] Figure 2 shows: Placement of windings and connection rings according to the present invention.

[0032] Figure 3 shows: Segregation and arrangement of bus bars in the terminal box for invented placement of windings and connection rings in accordance with the present invention.

[0033] The figures depict embodiments of the disclosure for purposes of illustration only. One skilled in the art will readily 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.

DETAIL DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS:

[0034] 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 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.

[0035] In conventional multiphase machines, windings are placed in the stator core such that the leads of the coils are brought out from one side of the stator core inside the frame where they are brazed/ terminated to the connection rings of respective phases. All the connection rings are placed on one side of the stator core inside the stator frame (101). As the number of phases increases, the number of connection rings of multiphase machine also increases. When the windings and connection rings are placed on only one side of the stator core, terminations of coil leads to connection rings, accessibility and ease of maintenance of connection rings becomes difficult and the structural stability also reduces.

[0036] Hence, there is a need for an optimal placement of windings and connection rings inside the stator frame of multiphase machine. In the present invention, the windings and connection rings of multiphase machine are placed on both sides of stator core in order to achieve ease of terminations, accessibility, maintenance and structural stability of machine by aligning the center of stator core with the center of bearings nearly or exactly.

[0037] In the present invention directing to Multi-phase electrical machines with novel placement of stator winding and connection rings, the number of winding phases and connection rings that are to be distributed on both sides of stator core of multiphase machine depends on whether the number of phases is even or odd. In case of multiphase machine with n-phases and n/3 independent 3-phase sets of windings with n/3 independent neutral points, connection rings of (n-3)/6 winding sets will be placed on one side and connection rings of (n+3)/6 winding sets will be placed on the other side of the stator core if n is odd whereas connection rings of n/6 winding sets will be placed on both sides of the stator core if n is even.

[0038] The present invention can also be applied to multiphase machine with single common neutral point. In case of multiphase machine with n phases having one neutral point, connection rings of (n-1)/2 phases will be placed on one side and connection rings of (n+1)/2 phases will be placed on the other side of the stator core if n is odd whereas connection rings of n/2 phases will be placed on both sides of the stator core if n is even with two neutral rings on either side of the stator core wherein these neutral rings are connected to each other outside of the machine frame inside the terminal box (102).

[0039] Unlike in conventional multiphase machine wherein all ending bars are connected to neutral rings on one side, ending bars of only few winding sets/few phases are connected to neutral rings on one side while starting bars of remaining winding sets/remaining phases are connected to neutral rings on the other side. For instance, a 6-phase multiphase machine with two independent sets of 3-phase windings having two independent neutral points has been considered for illustration. The number of slots and number of poles considered are 12 and 2 with asymmetrical winding configuration (30 phase difference between the two sets of 3-phase windings). In the existing configuration of multiphase machine, the neutral connection rings (CN1 and CN2) are placed on one side of the stator core as shown in Fig. 1 wherein the ending bars (R1E, Y1E and B1E) of one set of winding are connected to neutral connection ring CN1 and the ending bars (R2E, Y2E and B2E) of another set of winding are connected to neutral connection ring CN2. Six connection rings (not shown in Fig. 1) for starting bars (R1S, Y1S, B1S, R2S, Y2S and B2S) of two sets of 3-phase windings are also arranged on the same side of stator core along with neutral connection rings CN1 and CN2.

[0040] In the present invention of optimal placement of windings and connection rings of 6-phase multiphase machine, the coils are placed such that neutral connection ring CN1 is placed on one side of the stator core and the neutral connection ring CN2 is placed on the other side of the stator core as shown in Fig. 2 wherein the ending bars (R1E, Y1E and B1E) of one set of winding are connected to neutral connection ring CN1 and the starting bars (R2S, Y2S and B2S) of another set of winding are connected to neutral connection ring CN2. Three connection rings (not shown in Fig. 2) for starting bars (R1S, Y1S and B1S) of one set of 3-phase winding are also arranged on the same side of stator core where neutral connection ring CN1 is arranged. Similarly, three connection rings (not shown in Fig. 2) for ending bars (R1S, Y1S and B1S) of another set of 3-phase winding are also arranged on the same side of stator core where neutral connection ring CN2 is arranged.

[0041] A multiphase machine with odd number of phases and single common neutral is having a difference of only one connection ring between number of connection rings on either side of stator core compared to the multiphase machine with independent sets of windings and independent neutrals. For instance, a 15-phase machine with single common neutral have 8 connection rings on one side and 9 connection rings on the other side of stator core, whereas a 15-phase machine with 5 independent 3 phase sets of windings with 5 independent neutrals have 8 connection rings on one side and 12 connection rings on the other side of stator core.

[0042] Bus bars (BR1, BY1, BB1, BN1, BR2, BY2, BB2 and BN2) in the terminal box are segregated into two groups ((BR1, BY1, BB1 and BN1) and (BR2, BY2, BB2 and BN2)) in line with the number of connection rings placed on two ends of the stator core and arranged in such a way that each group of bus bars is close to its respective connection rings as shown in Fig. 3. Each connection ring placed beside the stator core is connected to its respective bus bar in the terminal box. For instance, CR1 is connected to the bus bar BR1.

[0043] Though the present invention has been illustrated in case of 6-phase machine with 12 slot - 2 pole combination and single layer winding for the sake of simplicity, it can be applied to any possible slot-pole combination for multiphase machine with any number of phases and any number of layers of winding and symmetrical/asymmetrical winding placement.

ADVANTAGES OF INVENTION

[0044] -Optimization of size of the machine;
[0045] -Increase in the ease of accessibility;
[0046] -Ease of maintenance of connection rings;
[0047] -Optimal placement of bus bars in the terminal box of multiphase machine.

[0048] Each of the appended claims defines a separate invention, which for infringement purposes is recognized as including equivalents to the various elements or limitations specified in the claims. Depending on the context, all references below to the "invention" may in some cases refer to certain specific embodiments only. In other cases, it will be recognized that references to the "invention" will refer to subject matter recited in one or more, but not necessarily all, of the claims.

[0049] Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified thus fulfilling the written description of all groups used in the appended claims.

[0050] It will be understood by those within the art that, in general, terms used 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 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 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 particulars 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 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 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 analogues 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 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 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 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 both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B”.

[0051] The above description does not provide specific details of manufacture or design of the various components. Those of skill in the art are familiar with such details, and unless departures from those techniques are set out, techniques, known, related art or later developed designs and materials should be employed. Those in the art are capable of choosing suitable manufacturing and design details.

[0052] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. It will be appreciated that several of the above-disclosed and other features and functions, or alternatives thereof, may be combined into other systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may subsequently be made by those skilled in the art without departing from the scope of the present disclosure as encompassed by the following claims.

[0053] The claims, as originally presented and as they may be amended, encompass variations, alternatives, modifications, improvements, equivalents, and substantial equivalents of the embodiments and teachings disclosed herein, including those that are presently unforeseen or unappreciated, and that, for example, may arise from applicants/patentees and others.

[0054] While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.
, Claims:We Claim
1.Multi-phase electrical machines comprises of:
windings/connection rings placed on both sides of stator core inside the stator frame by aligning the center of stator core with the center of bearings,
ending bars of winding sets/few phases are connected to neutral rings on one side and starting bars of remaining winding sets/remaining phases are connected to the neutral rings on the other side.
2. The Multi-phase electrical machines as claimed in claim 1, wherein in case of multiphase machine with n-phases and n/3 independent 3-phase sets of windings with n/3 independent neutral points, connection rings of (n-3)/6 winding sets are placed on one side and connection rings of (n+3)/6 winding sets are placed on the other side of the stator core if n is odd, whereas connection rings of n/6 winding sets are placed on both sides of the stator core if n is even.

3. The Multi-phase electrical machines as claimed in claim 1 or 2, wherein in case of multiphase machine with n phases having one neutral point, connection rings of (n-1)/2 phases are placed on one side and connection rings of (n+1)/2 phases are placed on the other side of the stator core if n is odd, whereas connection rings of n/2 phases are placed on both sides of the stator core if n is even with two neutral rings on either side of the stator core wherein the neutral rings are connected to each other outside the machine frame inside the terminal box.
4. The Multi-phase electrical machines as claimed in claims 1-3, wherein Bus bars (BR1, BY1, BB1, BN1, BR2, BY2, BB2 and BN2) in the terminal box are segregated into two groups ((BR1, BY1, BB1 and BN1) and (BR2, BY2, BB2 and BN2)) in line with the number of connection rings placed on two ends of the stator core and arranged in a way that each group of bus bars is close to its respective connection rings, in which each connection ring placed beside the stator core is connected to its respective bus bar in the terminal box.

5. The Multi-phase electrical machines as claimed in claims 1-4, wherein the multiphase machine with odd number of phases and single common neutral having a difference of one connection ring between number of connection rings on either side of stator core compared to the multiphase machine with independent sets of windings and independent neutrals, for example, 8 and 9 connection rings are provided on both sides of a 15-phase machine having one neutral point, and 8 and 12 connection rings are provided on both sides of a 15-phase machine with 5 independent 3-ph sets of windings with independent neutrals.
6. The Multi-phase electrical machines as claimed in claims 1-5, which is applicable to any possible slot-pole combination for multiphase machine with any number of phases and any number of layers of winding and symmetrical/asymmetrical winding placement without limiting to 6-phase machine with 12 slot - 2 pole combination and single layer winding such as herein described.