Claims:We claim:

1. A stator assembly 100 for an n-phase traction motor, comprising:
a plurality of rotor poles (Np), wherein ‘Np’ is a multiple of 2;
a plurality of segment teeth 101 (Ns), wherein ‘Ns’ is a multiple of n, wherein ‘n’ is indicative of number of phases associated to the n-phase traction motor, and wherein each segment tooth 101-1 is wound with a coil 103 corresponding to at least one of the phases, and wherein each segment tooth 101-1 comprises two terminals 203 indicating a start terminal 203-1 and an end terminal 203-2 of the coil 103 wound on said each segment tooth 101-1, wherein the terminals 203 are configured to form a plurality of parallel paths (pp), wherein the plurality of parallel paths (pp) are less than or equal to a greatest common divisor of (Ns, Np);
a plurality of phase bus bars 401 (n), associated to a traction motor, having a value greater than or equal to 3; and
a plurality of interconnecting bus bars 402 (n*(Ns/(n*pp)-1)*pp), wherein each interconnecting bus bar is configured to electrically interconnect one of the two terminals of the two predefined segment teeth of the plurality of segment teeth 101 in a predefined pattern;
wherein each of the plurality of phase bus bars (n) corresponds to one of the phases, configured to terminate the terminals 203 apart from the terminals interconnected via the plurality of interconnecting bus bars 402 such that each phase bus bar is configured to terminate ‘2*pp’ and ‘pp’ number of terminals for a delta network configuration and a star network configuration respectively, and wherein each phase bus bar is electrically connected to an external circuitry through one of a plurality of output end 201 terminals corresponding to the plurality of phases.

2. The stator assembly 100 for an n-phase traction motor as claimed in claim 1, wherein the plurality of phases comprises the ‘n’ phase network.

3. The stator assembly 100 for an n-phase traction motor as claimed in claim 2, wherein the plurality of segment teeth 101 along with coils comprising the n phase network is connected in the star network configuration or the delta network configuration.

4. The stator assembly 100 for an n-phase traction motor as claimed in claim 1, wherein each phase bus bar is an arc shaped flattened surface, and wherein each phase bus bar comprises a plurality of protruded terminals 202 with U-shaped pin hole or any other shape capable of abutting the terminals 203.

5. The stator assembly 100 for an n-phase traction motor as claimed in claim 1, wherein each interconnecting bus bar comprises at least two protruded terminals 202 with U-shaped pin hole or any other shape capable of abutting the terminals corresponding to the two terminals of the two adjacent segment teeth.

6. The stator assembly 100 for an n-phase traction motor as claimed in claim 4, wherein a plurality of protruded terminals 202 are L-shaped terminals, protruding radially outwards or radially inwards around the circumference of each phase bus bar.

7. The stator assembly 100 for an n-phase traction motor as claimed in claim 1, wherein the plurality of phase bus bars 401 are stacked in an axial direction or arranged concentrically in a radial direction or a combination of both.

8. The stator assembly 100 for an n-phase traction motor as claimed in claim 1, wherein the external circuitry comprises one or more power electronics devices.

9. The stator assembly 100 for an n-phase traction motor as claimed in claim 1, wherein an electrically insulating material is used to provide structural rigidity and insulation between each of the plurality of phase bus bar 401, each of the plurality of interconnecting bus bar 402, coils and terminals 203, wherein the electrically insulating material is thermally conducting thereby allowing heat dissipation from each of the plurality of interconnecting bus bars 402.

10. The stator assembly 100 for an n-phase traction motor as claimed in claim 1, wherein the star network configuration comprises a neutral bus bar 701 configured to terminate ‘pp*n’ terminals apart from the terminals interconnected via the plurality of interconnecting bus bars 402 and the ‘pp’ terminals terminated by the plurality of phase bus bars 401.

Dated this 20th Day of August, 2020

Priyank Gupta
Agent for the Applicant
IN/PA- 1454
, Description:FORM 2

THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENT RULES, 2003

COMPLETE SPECIFICATION

(See Section 10 and Rule 13)

Title of invention:
A STATOR ASSEMBLY FOR AN N-PHASE TRACTION MOTOR

APPLICANT
Varroc Engineering Limited.
An Indian entity having address as:
L-4, MIDC Waluj,
Aurangabad - 431136,
Maharashtra, India

The following specification describes the invention and the manner in which it is to be performed.
CROSS-REFERENCE TO RELATED APPLICATIONS AND PRIORITY
The present application does not claim priority from any other patent application.
TECHNICAL FIELD
The present subject matter described herein, in general, relates to the field of electromechanical assembly. More particularly, the invention relates to a stator assembly for a traction motor.
BACKGROUND
A traction motor is known for propulsion of an electric vehicle. It primarily consists of a rotor assembly and a stator assembly. The stator assembly is the static member and the rotor assembly is a rotating member. The stator assembly consists of a stator core, coils, and a bus bar assembly. The bus bar assembly is a set of metallic strips connected to the coils. This bus bar assembly is designed to connect these coils in a predetermined fashion depending on the number of phases of the motor.

The stator of traction motor may be designed as a single structure of stator core or a stator core made of various segments. The single structure of stator core and the segmented stator core comprise of teeth and yoke. The teeth encompass air gaps which are termed as slots through which the copper or aluminium wire or any conducting material which can act as an electrical conductor, typically round, rectangular or square in shape, is wound around the teeth. These slots have small openings which do not allow sufficient space for the conductors of coils to enter the slot area. In a single structure stator core, as multiple wires or conductors are to be passed through this gap manually or using an automated machine, it is tedious, complex, and time consuming process. In case of insufficient conductors, the motor may not be able to deliver the desired torque. The limitation of small opening to the slots is solved using segmented teeth instead of a single stator core structure. Moreover, when conductors are wound over the stator segments, the coil present on the segmented stator comprise of only two terminals namely start terminal and end terminal. The termination of these ends to form a winding which is a three-phase winding in the present invention is complex to be performed while manufacturing. If these terminals are not accurately terminated, it may decrease the performance of the traction motor.
Multiple busbars are arranged to implement various phases of an electrical network in the stator assembly. These multiple rings are posing space and process constraints, joining of bus bar terminals and stator coil end terminals is complex process, because the joining terminals should move multi axis to reach the terminals.
The automated manufacturing of such stator assemblies is difficult as multiple segments are required to be wound together in series. Also, assembly of these wound segments is complex as multiple segments wound in series are difficult to handle at assembly line. Such series winding of segments may also result in alignment errors during assembly of segment teeth.
Moreover, the bus-bar assembly is inserted in a mould which is made of electrically insulating material. Material used for moulding generally have poor thermal conductivity which results in high winding temperature. In order to improve heat dissipation from bus bar assembly to enclosure, additional surface area is required.
Thus, there is a long-standing need for an improved stator assembly for a traction motor that alleviates the aforementioned technical challenges/drawbacks. Therefore, the purpose of the present subject matter is to develop a bus bar assembly in order to enhance the termination of one or more terminal structures of the coils with improved heat dissipation.

SUMMARY

This summary is provided to introduce the concepts related to a stator assembly for a n-phase traction motor and the concepts are further described in the detail description. This summary is not intended to identify essential features of the claimed subject matter nor it is intended to use in determining or limiting the scope of claimed subject matter.

In one implementation, the present subject matter describes a stator assembly for an n-phase traction motor. The stator assembly may comprise a plurality of rotor poles (Np), wherein ‘Np’ is a multiple 2. The stator assembly may further comprise a plurality of segment teeth (Ns), wherein ‘Ns’ is a multiple of n, wherein ‘n’ is indicative of number of phases associated to the n-phase traction motor. Each segment tooth may be wound with a coil corresponding to at least one of the phases. Each segment tooth may comprise two terminals indicating a start terminal and an end terminal of the coil wound on said each segment tooth. The terminals may be configured to form a plurality of parallel paths (pp), wherein the plurality of parallel paths (pp) may be less than or equal to a greatest common divisor of (Ns, Np). The stator assembly may comprise a plurality of phase bus bars (n), associated to a traction motor, having a value greater than or equal to 3. The stator assembly may further comprise a plurality of interconnecting bus bars (n*(Ns/(n*pp)-1)*pp), wherein each interconnecting bus bar may be configured to electrically interconnect one of the two terminals of the two predefined segment teeth of the plurality of segment teeth in a predefined pattern. Each of the plurality of phase bus bars (n) may correspond to one of the phases, configured to terminate the terminals apart from the terminals interconnected via the plurality of interconnecting bus bars such that each phase bus bar may be configured to terminate ‘2*pp’ and ‘pp’ number of terminals for a delta network configuration and a star network configuration respectively. Each phase bus bar may be electrically connected to an external circuitry through one of a plurality of output end terminals corresponding to the plurality of phases.

BRIEF DESCRIPTION OF DRAWINGS

The detailed description is described with reference to the accompanying figures. In the Figures, the left-most digit(s) of a reference number identifies the Figure in which the reference number first appears. The same numbers are used throughout the drawings to refer like features and components.

Figure 1 illustrates a stator assembly 100 for an n-phase traction motor, in accordance with an embodiment of a present subject matter.

Figure 2 illustrates a perspective view 200 of the stator assembly with a bus bar assembly 102, in accordance with an embodiment of a present subject matter.

Figure 3A illustrates a typical conventional stator assembly 800 comprising a single coil 103.

Figure 3B illustrates a view 300 of a single segment 101-1, in accordance with an embodiment of a present subject matter.

Figure 4 illustrates a perspective view 400 of a plurality of phase bus bars 401 and a plurality of interconnecting bus bars 402, in accordance with an embodiment of a present subject matter.

Figure 5a and Figure 5b illustrates cross sectional views of the bus bar assembly 102, in accordance with the embodiment of the present subject matter.

Figure 6a and Figure 6b illustrates mapping of the connections in the stator assembly with the connections in a delta configuration, in accordance with the embodiment of the present subject matter.

Figure 7a and Figure 7b illustrates mapping of the connections in the stator assembly with the connections in a star configuration, in accordance with the embodiment of the present subject matter.

DETAILED DESCRIPTION

Reference throughout the specification to “various embodiments,” “some embodiments,” “one embodiment,” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases “in various embodiments,” “in some embodiments,” “in one embodiment,” or “in an embodiment” in places throughout the specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner in one or more embodiments.

Figure 1 illustrates a stator assembly 100 for an n-phase traction motor, in accordance with an embodiment of a present subject matter. The traction motor may be used to provide a tractive force to electric and hybrid vehicles. A motor generally comprises a rotor and a stator assembly wherein the stator assembly comprises a stator core, a set of coils and a busbar assembly. In one embodiment, the stator assembly 100 illustrated in figure 1 comprises a segmented stator core, wherein the segmented stator core comprises a plurality of segment teeth 101. In one embodiment, each segment tooth of the plurality of segment teeth 101 may be wound with a coil 103. The terminals of the coils may be terminated by a busbar assembly 102.

Referring now to figure 3B, a view 300 of a single segment tooth 101-1 is illustrated in accordance with an embodiment of a present subject matter. In one embodiment, each segment tooth 101-1 of the plurality of segment teeth 101 may be wound with an individual coil 103. In one embodiment, the coil 103 may be, but is not limited to, a copper coil. Thus, each coil 103 comprises a start terminal 203-1 an end terminal 203-2. The stator assembly 100 for a traction motor may comprise each segment tooth 101-1 wound identically and uniformly with separate coils.

Figure 2 illustrates a perspective view 200 of the stator assembly 100 with a bus bar assembly 102, in accordance with an embodiment of a present subject matter. In one embodiment, the stator assembly 100 may comprise an individual coil 103 wound around each of the plurality of segment teeth 101. Thus, a plurality of terminals 203 comprising start terminals and end terminals may be dragged out of an upper end of the plurality of segment teeth 101. In one embodiment, said plurality of terminals 203 may be terminated by the busbar assembly 102, wherein the plurality of terminals 203 may be welded on corresponding plurality of legs 202 of the busbar assembly 102. The plurality of legs 202 may be protruded radially outwards from the busbar assembly 102. In one embodiment, the plurality of legs 202 may comprise U shaped aperture in order to weld the plurality of terminals 203 in said U shaped apertures. In one embodiment, the plurality of terminals 203 may be welded using technique, but is not limited to, such as point welding. In one embodiment, the busbar assembly 102 may comprise a plurality of output end terminals 201 raised upwards from the busbar assembly 102 in order to allow connection with external electronic circuitry. In one embodiment, the external electronic circuitry may comprise one or more power electronics devices.
Figure 4 illustrates a perspective view 400 (e.g. an expanded view) of a plurality of phase bus bars 401 and a plurality of interconnecting bus bars 402, in accordance with an embodiment of a present subject matter. In one embodiment, the busbar assembly 102 may comprise a plurality of phase busbars 401 and a plurality of interconnecting busbars 402. Each busbar may contain two portions including annular shaped conductors called holder and legs connected to the holders. In one embodiment, the holders and legs may either be made of separate pieces and joint or made of a single sheet metal stamping. In one embodiment, each phase bus bar may be an arc shaped flattened surface, thereby reducing the weight and material required to produce the phase busbars. In one embodiment, each phase bus bar may comprise a plurality of protruded terminals 202, corresponding to the terminals terminated by the plurality of phase bus bars 401, protruding radially outwards or radially inwards around the circumference of each phase bus bar. In one embodiment, the plurality of interconnecting busbars 402 may be U shaped. In one embodiment, each interconnecting bus bar may comprise at least two protruded terminals 202 corresponding to the two terminals of the two adjacent segment teeth. In an embodiment, at least the protruded terminals 202 may be L-shaped terminals. In one embodiment, the protruded L-shaped terminals 202 may comprise a U-shaped pin hole or any other shape capable of abutting the plurality of terminals 203. In one embodiment, the busbars may be arranged and embedded in the structure of the busbar assembly 102. The plurality of L-shaped terminals 202 may be fixed in a corresponding plurality of apertures 403. The plurality of phase bus bars 401 may be stacked in an axial direction or arranged concentrically in a radial direction or a combination of both.

In one embodiment, each interconnecting bus bar may be configured to electrically interconnect one of the two terminals of the two predefined segment teeth of the plurality of segment teeth in a predefined pattern. It is to be noted herein that, the series connection between individually wound segment teeth is enabled by introducing the plurality of interconnecting busbars 402 in the bus-bar assembly 102. The individually wound segment teeth may be assembled easily at the assembly line. Such a structure may also simplify stator cylindrical shape formation at the end of assembly process. Thus, such an interconnection may be done in order to form a multi-phase network. The plurality of interconnecting bus bars 402, thus prevent the problem of mis-alignment. Each segment tooth 101-1 is wound with a single coil 103, thus the plurality of interconnecting bus bars 402 are configured to interconnect the predefined ends of the coil 103. Such arrangement overcomes the lacunae faced by the conventional stator assembly as shown in figure 3 A.

As shown in figure 3A, a stator assembly 300’ comprises multiple segment teeth 101 which are interconnected with a single coil 103. In other words, the segment teeth 101 are wound throughout by a single coil which, may leads to alignment and uniformity errors. As can be seen in the figure 3A, a portion 301’ of the coil 103 in a form of a jumper is shown which is adapted for connecting the coil 103 with the adjacent segments. In scenarios where the coil 103 is to be connected to a segment teeth which may not be consecutive adjacent to each other, or to the terminals of the coil of adjacent segment teeth which may not be consecutive adjacent to each other, then the length of the jumper is increased and the coil has to be dragged till the next predefined terminal of the segment tooth which has to be connected. In such cases, the assembly becomes complex in terms of winding remote terminals of the segment teeth in stator assembly, and further becomes difficult to handle during assembly time, and furthermore results in increased material requirement for the coil 103. The stator assembly may also become bulkier and costly due to increase in the material requirement. In order to avoid the above lacunae/drawbacks, the plurality of interconnecting bus bars 402 are used to connect the predefined terminals of the stator assembly 100. In one embodiment, the plurality of interconnecting bus bars 402 in the bus-bar assembly 102 may increase the surface area for dissipating heat generated in the coils on segments.

Figure 5a and Figure 5b illustrates cross sectional views of the bus bar assembly 102, in accordance with the embodiment of the present subject matter. As can be seen, the distance between a bottom surface 501 of the bus bar assembly 102 and outward projection of each of the plurality of L-shaped terminals 202 may be “d”.

In one embodiment, the plurality of phases of the stator assembly 100 may comprise ‘n’ phase network. The plurality of segment teeth 101 along with each of the coil 103 comprising the n phase network may be connected in a star network configuration or a delta network configuration.

Figure 6a and Figure 6b illustrates mapping of the connections in the stator assembly with the connections in a delta network configuration , in accordance with the embodiment of the present subject matter. In one embodiment, the stator assembly 100 may be connected in a delta network configuration to a plurality of phases. In one preferred embodiment, the ‘n’ phase network may be a 3 phases network. However, the ‘n’ phase network may include, but are not be limited to, 5 phase network, 6 phase network, and the like.

Referring to figure 6a, a delta network connection for a three phase network is illustrated in accordance to an embodiment of the present subject matter. In one embodiment, the three phases of the network may be phase R, phase Y and phase B. In one embodiment, each phase of the delta network may comprise two pairs of coils, wherein each coil in a pair of windings may be connected in series with each other. Further, the said two pairs of coils may be connected in parallel with each other. Therefore, each phase may comprise four coils. Considering phase R, the four coils may include A1, A2, A3 and A4. The coils A1 and A2 may be connected in series with each other. Therefore, one terminal end of A1 may be connected to one terminal end of A2. Similarly, the coils A3 and A4 may be connected in series with each other. Therefore, one terminal end of A3 may connected to one terminal end of A4. Thus, two pairs of coils are formed. These two pairs of coils may be connected in parallel with each other. Therefore, unconnected terminal end of A2 may be connected to unconnected terminal end of A4. Similarly, unconnected terminal end of A1 may be connected to unconnected terminal end of A3.

Further, considering phase B, the four coils may include B1, B2, B3 and B4. The coils B1 and B2 may be connected in series with each other. Therefore, one terminal end of B1 may be connected to one terminal end of B2. Similarly, the coils B3 and B4 may be connected in series with each other. Therefore, one terminal end of B3 may connected to one terminal end of B4. Thus, two pairs of coils are formed. These two pairs of coils may be connected in parallel with each other. Therefore, unconnected terminal end of B2 may be connected to unconnected terminal end of B4. Similarly, unconnected terminal end of B1 may be connected to unconnected terminal end of B3.

Furthermore, considering phase Y, the four coils may include C1, C2, C3 and C4. The coils C1 and C2 may be connected in series with each other. Therefore, one terminal end of C1 may be connected to one terminal end of C2. Similarly, the coils C3 and C4 may be connected in series with each other. Therefore, one terminal end of C3 may connected to one terminal end of C4. Thus, two pairs of coils are formed. These two pairs of coils may be connected in parallel with each other. Therefore, unconnected terminal end of C2 may be connected to unconnected terminal end of C4. Similarly, unconnected terminal end of C1 may be connected to unconnected terminal end of C3.

Thus, it may be noted that, the coil A1 is connected in series with the coil A2, the coil A3 is connected in series with the coil A4 and the series combination of the coils A1 and A2 is connected in parallel with the series combination of the coils A3 and A4. Similar connections may be obtained for with the coils B1, B2, B3, B4 and C1, C2, C3, C4.

In one embodiment, a three phase delta network configuration may be formed by the phases R, Y and B. The phase R may comprise a connecting point which may be configured to connect a common terminal end of the two parallelly connected coils A2 and A4 along with a common terminal end of the two parallelly connected coils B1 and B3. Similarly, phase Y may comprise a connecting point which may be configured to connect a common terminal end of the two parallelly connected coils A1 and A3 along with a common terminal end of the two parallelly connected coils C2 and C4. The phase B may comprise a connecting point which may be configured to connect a common terminal end of the two parallelly connected coils B2 and B4 along with a common terminal end of the two parallelly connected coils C1 and C3.

Figure 7a and Figure 7b illustrates mapping of the connections in the stator assembly with the connections in a star configuration, in accordance with the embodiment of the present subject matter. Referring to figure 7a, a star network connection for a three phase network is illustrated. The three phases of the network may be namely phase R, phase Y and phase B. Each phase may comprise four coils.
The series and parallel connections of each of the four coils in each of the three phases may be similar to that of the delta network configuration as illustrated in figure 6a. Thus, the phase R may comprise the coil A1 being connected in series with coil A2, the coil A3 being connected in series with the coil A4 and the series combination of the coils A1 and A2 is connected in parallel with the series combination of the coils A3 and A4. Similarly, phase Y may comprise the coil B1 being connected in series with coil B2, the coil B3 being connected in series with the coil B4 and the series combination of the coils B1 and B2 is connected in parallel with the series combination of the coils B3 and B4. Similarly, phase B may comprise the coil C1 being connected in series with coil C2, the coil C3 being connected in series with the coil C4 and the series combination of the coils C1 and C2 is connected in parallel with the series combination of the coils C3 and C4. Thus, a three phase star network configuration may be formed by the phases R, Y and B. The phase R may comprise a connecting point which may be configured to connect a common terminal end of the two parallelly connected coils A2 and A4. Similarly, phase Y may comprise a connecting point which may be configured to connect a common terminal end of the two parallelly connected coils B2 and B4. The phase B may comprise a connecting point which may be configured to connect a common terminal end of the two parallelly connected coils C2 and C4. The common terminal ends of each of the phases R, Y and B may be connected to form an intersecting point of connection through which a neutral terminal may be drawn out.

Now referring to figure 6b and figure 7b, the stator assembly 102 for an n-phase traction motor may comprise a plurality of rotor poles (not shown in figure), and a plurality of segment teeth 101, a plurality of phase bus bars 401 and a plurality of interconnecting bus bars 402. The plurality of rotor poles may be indicated by Np and wherein ‘Np’ may be a multiple of 2. The plurality of segment teeth 101 of the stator assembly 100 may be denoted by Ns, wherein ‘Ns’ may be a multiple of n and wherein ‘n’ may be indicative of number of phases, associated to the traction motor, having a value greater than or equal to 3. In one embodiment, each segment tooth 101-1 may be wound with a coil 103 corresponding to at least one of the phases. Each segment tooth 101-1 may comprise two terminals 203 indicating a start terminal 203-1 and an end terminal 203-2 of the coil 103 wound on said each segment tooth 101-1. In one embodiment, the terminals 203 may be configured to form a plurality of parallel paths (pp), wherein the plurality of parallel paths (pp) may be less than or equal to a greatest common divisor of (Ns, Np). In one embodiment, the plurality of parallel paths (pp) may be the parallelly connected coils shown in figure 6a and 7a for both delta and star network configuration. The plurality of phase bus bars 401 may be denoted by (n). The plurality of interconnecting bus bars 402 may be denoted by (n*(Ns/(n*pp)-1)*pp), wherein each interconnecting bus bar may be configured to electrically interconnect one of the two terminals of the two predefined segment teeth of the plurality of segment teeth 101 in a predefined pattern. In one embodiment, each of the plurality of phase bus bars (n) corresponds to one of the phases. Each of the plurality of phase bus bars (n) may be configured to terminate the terminals 203 apart from the terminals interconnected via the plurality of interconnecting bus bars 402 such that each phase bus bar may be configured to terminate ‘2*pp’ and ‘pp’ number of terminals for a delta network configuration and a star network configuration respectively. In one embodiment, each phase bus bar may be electrically connected to an external circuitry through one of a plurality of output end terminals 201 corresponding to the plurality of phases.

Referring to figure 6b, mapping of the connections in the stator assembly 100 with the connections in a delta network configuration shown in figure 6a is illustrated. In one embodiment, the stator assembly 100 with the connections in delta network configuration may comprise three phases bus bars corresponding to each phase in the delta network configuration. Therefore, the three phase bus bars may be namely, the phase R 401-1, the phase Y 401-2, and the phase B 401-3. The stator assembly 100 may comprise 12 segment teeth comprising individual coil wound round each of the segment teeth. Thus, each coil wound around each of the 12 segment teeth may be denoted by A1, A2, A3, A4, B1, B2, B3, B4, C1, C2, C3 and C4. Considering figure 6b, these 12 coils hereafter is interchangeably referred as “12 segment teeth”. Each of the 12 segment teeth may comprise two terminals namely the start terminal denoted by “SP” and end terminal denoted by “EP”. The stator assembly 100 may comprise a plurality of interconnecting bus bars 402. The start and end terminals of each of the 12 segments may be terminated in a predefined pattern by the phase bus bars 401 and the interconnecting bus bars 402. In one embodiment, the 12 segment teeth may be placed adjacent to each other in a predefined pattern forming a circular arrangement.

In one embodiment, the predefined pattern in which the segment teeth may be placed adjacent to each other in a circular arrangement may be clockwise and may comprise the segment teeth including A1, A2, C1, C2, B1, B2, A3, A4, C3, C4, B3 and B4 respectively. The start terminal SP1 of the segment tooth A1 may be terminated by phase Y 401-2 i.e. the start terminal SP1 of the segment tooth A1 is connected to the phase bus bar Y 401-2. The end terminal of the segment tooth A1 is connected to the start terminal of the segment tooth A2 via an interconnecting bus bar. The end terminal EP1 of the segment tooth A2 is terminated by the phase R 401-1. Thus, it may be noted that this physical connection of the terminals is corresponding to the series connection of coils A1 and A2 illustrated in figure 6a. Further, the start terminal SP3 of segment tooth C1 is terminated by phase B 401-3. The end terminal of segment tooth C1 is connected to the start terminal the segment tooth C2 via an interconnecting bus bar. The end terminal EP3 of the segment tooth C2 is terminated by phase Y 401-2. Thus, it may be noted that this physical connection of the terminals is corresponding to the series connection of coils C1 and C2 illustrated in figure 6a. Further, the start terminal SP5 of segment tooth B1 is terminated by phase R 401-1. The end terminal of segment tooth B1 is connected to the start terminal of B2 via an interconnecting bus bar. The end terminal EP5 of segment tooth B2 is terminated by the phase B 401-3. Thus, it may be noted that this physical connection of the terminals is corresponding to the series connection of coils B1 and B2 illustrated in figure 6a. Further, the start terminal SP2 of segment tooth A3 is terminated by phase Y 401-2. The end terminal of segment tooth A3 is connected with the start terminal of the segment tooth A4 via an interconnecting bus bar. The end terminal EP2 of the segment tooth A4 is terminated by phase R 401-1. Thus, it may be noted that this physical connection of the terminals is corresponding to the series connection of coils A3 and A4 along with parallel connection of series connected coils A1 and A2, wherein one end of the parallel connection is terminated at phase Y and another end is terminated at phase R, as illustrated in figure 6a. Further, the start terminal SP4 of segment tooth C3 is terminated by phase B 401-3. The end terminal of segment tooth C3 is connected with the start terminal of segment tooth C4 via an interconnecting bus bar. The end terminal EP4 of segment tooth C4 is terminated by phase Y 401-2. Thus, it may be noted that this physical connection of the terminals is corresponding to the series connection of coils C3 and C4 along with parallel connection of series connected coils C1 and C2 wherein one end of the parallel connection is terminated at phase B and another end is terminated at phase Y, as illustrated in figure 6a. Further, the start terminal SP6 of the segment tooth B3 is terminated by phase R 401-1. The end terminal of segment tooth B3 is connected to the start terminal of segment tooth B4 via an interconnecting bus bar. The end terminal EP6 of the segment tooth B4 is terminated by phase B 401-3. Thus, it may be noted that this physical connection of the terminals is corresponding to the series connection of coils B3 and B4 along with parallel connection of series connected coils B1 and B2 wherein one end of the parallel connection is terminated at phase B and another end is terminated at phase Y, as illustrated in figure 6a. Therefore, a three phase delta network configuration may be constructed with said physical connections of the terminals of the coils 203, the plurality of phase bus bars 401 and the plurality of interconnecting bus bars 402.

In a preferred embodiment, consider an example of a delta network configuration for the stator motor assembly 100 with following specifications:
The plurality of segment teeth (Ns) is equal to 12.
The plurality of rotor poles (Np) may be 10 or 14, which are multiples of 2.
The plurality of parallel paths (pp) is equal to 2, wherein ‘pp’ may be less than or equal to a greatest common divisor of (Ns, Np).
The plurality of phase bus bars (n) is equal to 3, wherein ‘n’ is indicative of number of phases.
The plurality of interconnecting bus bars (n*(Ns/(n*pp)-1)*pp) is equal to (3*(12/(3*2)-1)*2) = 6.
Number of terminals terminated by each phase bus bar (2*pp) is equal to (2*2) = 4.

Referring to figure 7b, mapping of the connections in the stator assembly 100 with the connections in a star network configuration shown in figure 7a is illustrated. In one embodiment, the stator assembly 100 with the connections in star network configuration may comprise three phases bus bars corresponding to each phase in the star network configuration. Therefore, the three phase bus bars may be namely, the phase R 401-1, the phase Y 401-2, and the phase B 401-3. The star network configuration may comprise a neutral bus bar 701. The stator assembly 100 may comprise similar sequential circular arrangement of 12 segment teeth as illustrated in the delta network configuration in figure 6b. The termination of the plurality of terminals 203 of the coils wound round the plurality of segment teeth varies in the star network configuration as compared to the delta network configuration.

In one embodiment, the start terminal SP1 of the segment tooth A1 may be terminated by phase R 401-1 i.e. the start terminal SP1 of the segment tooth A1 is connected to the phase bus bar R 401-1. The end terminal of the segment tooth A1 is connected to the start terminal of the segment tooth A2 via an interconnecting bus bar. The end terminal EP1 of the segment tooth A2 is terminated by the neutral bus bar 701. Thus, it may be noted that this physical connection of the terminals is corresponding to the series connection of coils A1 and A2 illustrated in figure 7a. Further, the start terminal SP3 of segment tooth C1 is terminated by phase B 401-3. The end terminal of segment tooth C1 is connected to the start terminal the segment tooth C2 via an interconnecting bus bar. The end terminal EP3 of the segment tooth C2 is terminated by neutral bus bar 701. Thus, it may be noted that this physical connection of the terminals is corresponding to the series connection of coils C1 and C2 illustrated in figure 7a. Further, the start terminal SP5 of segment tooth B1 is terminated by phase Y 401-2. The end terminal of segment tooth B1 is connected to the start terminal of B2 via an interconnecting bus bar. The end terminal EP5 of segment tooth B2 is terminated by the neutral bus bar 701. Thus, it may be noted that this physical connection of the terminals is corresponding to the series connection of coils B1 and B2 illustrated in figure 7a. Further, the start terminal SP2 of segment tooth A3 is terminated by phase R 401-1. The end terminal of segment tooth A3 is connected with the start terminal of the segment tooth A4 via an interconnecting bus bar. The end terminal EP2 of the segment tooth A4 is terminated by the neutral bus bar 701. Thus, it may be noted that this physical connection of the terminals is corresponding to the series connection of coils A3 and A4 along with parallel connection of series connected coils A1 and A2, wherein one end of the parallel connection is terminated at phase R and another end is terminated at neutral, as illustrated in figure 7a. Further, the start terminal SP4 of segment tooth C3 is terminated by phase B 401-3. The end terminal of segment tooth C3 is connected with the start terminal of segment tooth C4 via an interconnecting bus bar. The end terminal EP4 of segment tooth C4 is terminated by the neutral bus bar 701. Thus, it may be noted that this physical connection of the terminals is corresponding to the series connection of coils C3 and C4 along with parallel connection of series connected coils C1 and C2 wherein one end of the parallel connection is terminated at phase B and another end is terminated at neutral, as illustrated in figure 7a. Further, the start terminal SP6 of the segment tooth B3 is terminated by phase Y 401-2. The end terminal of segment tooth B3 is connected to the start terminal of segment tooth B4 via an interconnecting bus bar. The end terminal EP6 of the segment tooth B4 is terminated by the neutral bus bar 701. Thus, it may be noted that this physical connection of the terminals is corresponding to the series connection of coils B3 and B4 along with parallel connection of series connected coils B1 and B2 wherein one end of the parallel connection is terminated at phase Y and another end is terminated at neutral, as illustrated in figure 7a. Therefore, a three phase star network configuration may be constructed with said physical connections of the terminals of the coils 203, the plurality of phase bus bars 401, neutral bus bar 701 and the plurality of interconnecting bus bars 402.

In a preferred embodiment, consider an example of a star network configuration for the stator motor assembly 100 with following specifications:
The plurality of segment teeth (Ns) is equal to 12.
The plurality of rotor poles (Np) may be 10 or 14, which are multiples of 2.
The plurality of parallel paths (pp) is equal to 2, wherein ‘pp’ may be less than or equal to a greatest common divisor of (Ns, Np).
The plurality of phase bus bars (n) is equal to 3, wherein ‘n’ is indicative of number of phases.
The plurality of interconnecting bus bars (n*(Ns/(n*pp)-1)*pp) is equal to (3*(12/(3*2)-1)*2) = 6.
Number of terminals terminated by each phase bus bar (pp) is equal to 2.
In one embodiment, neutral bus bar 701 of the the star network configuration may be configured to terminate ‘pp*n’ terminals apart from the terminals interconnected via the plurality of interconnecting bus bars. Therefore, the terminals terminated by the neutral bus bar equals to (2*3) = 6.

In one embodiment, preferred examples of various specifications for delta and star network configuration are illustrated in Table 1 below:

Sr. No. Phases Slots (Ns) Poles (Np) Parallel Paths (pp) Coils in series per phase Inter connectors per phase (Icp) Total interconnectors (IC) Delta: coil terminals per bus bar Star: coil terminals per bus bar
n Ns Np pp = GCD (Ns, Np) Ns/n/pp ICp = (Ns/(n*pp) - 1 )*pp IC = ICp * m 2*pp pp
1 3 6 4 2 1 0 0 4 2
2 3 6 4 1 2 1 3 2 1
3
4 3 9 6 3 1 0 0 6 3
5 3 9 6 1 3 2 6 2 1
6
7 3 9 8 1 3 2 6 2 1
8
9 3 9 10 1 3 2 6 2 1
10
11 3 9 12 3 1 0 0 6 3
12 3 9 12 1 3 2 6 2 1
13
14 3 9 14 1 3 2 6 2 1
15
16 3 12 8 4 1 0 0 8 4
17
18 3 12 10 2 2 2 6 4 2
19 3 12 10 1 4 3 9 2 1
20
21 3 12 14 2 2 2 6 4 2
22 3 12 14 1 4 3 9 2 1
23
24 3 12 16 4 1 0 0 8 4
25 3 12 16 2 2 2 6 4 2
26 3 12 16 1 4 3 9 2 1
27
28 3 15 8 1 5 4 12 2 1
29
30 3 15 10 5 1 0 0 10 5
31 3 15 10 1 5 4 12 2 1
32
33 3 15 14 1 5 4 12 2 1
34 3 15 16 1 5 4 12 2 1
35
36 3 15 20 5 1 0 0 10 5
37 3 15 20 1 5 4 12 2 1
38
39 3 18 14 2 3 4 12 4 2
40 3 18 14 1 6 5 15 2 1
41
42 3 18 16 2 3 4 12 4 2
43 3 18 16 1 6 5 15 2 1
44
45
46 4 8 6 2 1 0 0 4 2
47 4 8 6 1 2 1 4 2 1
48
49 4 16 10 2 2 2 8 4 2
50 4 16 10 1 4 3 12 2 1
51
52 4 16 14 2 2 2 8 4 2
53 4 16 14 1 4 3 12 2 1
54
55 4 16 18 2 2 2 8 4 2
56 4 16 18 1 4 3 12 2 1
57
58 4 16 20 4 1 0 0 8 4
59 4 16 20 2 2 2 8 4 2
60 4 16 20 1 4 3 12 2 1
61
62 4 16 22 2 2 2 8 4 2
63 4 16 22 1 4 3 12 2 1
64
65 4 16 26 2 2 2 8 4 2
66 4 16 26 1 4 3 12 2 1
67
68
69 5 10 6 2 1 0 0 4 2
70 5 10 6 1 2 1 5 2 1
71
72 5 10 8 2 1 0 0 4 2
73 5 10 8 1 2 1 5 2 1
74
75 5 10 12 2 1 0 0 4 2
76 5 10 12 1 2 1 5 2 1

Table 1
In one embodiment, the traction motor with the stator assembly 100 may be used to provide tractive force to electric and hybrid vehicles. In one embodiment, an electrically insulating material is used to provide insulation between each phase bus bar, each interconnecting bus bar, coils, and terminals. The electrically insulating material may be thermally conducting or non-conducting. Therefore, such insulating material may provide structural rigidity to the stator assembly 100 and allows heat dissipation from each interconnecting bus bar.

Although implementations for the stator assembly for an n-phase traction motor have been described in language specific to structural features and/or methods, it is to be understood that the appended claims are not necessarily limited to the specific features or methods described. Rather, the specific features and methods are disclosed as examples of implementations for the stator assembly for an n-phase traction motor.