BR112019025872B1 - FLAT COMPOSITE STRUCTURE FOR USE IN AN AXIAL FLOW MOTOR OR GENERATOR - Google Patents

Abstract

The present invention relates to a planar composite structure (PCS) for use in an axial flux motor or generator that may include a conductive layer disposed on a dielectric layer, with the conductive layer comprising conductive traces forming portions of at least two windings which, when energized, generate magnetic flux to at least two corresponding phases of the motor or generator. The PCS may additionally or alternatively include a first conductive layer comprising first conductive traces that form a first portion of a winding which, when energized, generates magnetic flux to a first phase of the motor or generator, and a second conductive layer, which is other than the at least one first conductive layer, which comprises second conductive traces forming a second portion of the winding. The first portion of the winding may be connected in series with the second portion of the winding, and the first and second portions of the winding may be configured and arranged so that an equal amount of current flows through each of the first and second portions of the winding. .

Description

Related Requests

[0001] The present application claims priority to each of (A) US Patent Application Serial No. 15/852,972, entitled PLANAR COMPOSITE STRUCTURES AND ASSEMBLIES FOR AXIAL FLUX MOTORS AND GENERATORS, filed on December 22, 2017, and ( B) US Provisional Patent Application Serial No. 62/530,552, entitled STRUCTURES AND METHODS OF STACKING SUBASSEMBLIES IN PLANAR COMPOSITE STATORS TO OBTAIN HIGHER WORKING VOLTAGES, filed on July 10, 2017. The total contents of the above applications, publications and patents , are incorporated herein by reference in their entirety and for all purposes.

Background

[0002] It is known to use a flat composite structure (PCS) as a stator in an axial flux motor or generator. An example of said stator is described in US patent No. 7,109,625 ("the '625 patent").

summary

[0003] In some embodiments, the planar composite structure (PCS) for use in an axial flux motor or generator comprises a dielectric layer, and a first conductive layer disposed on the dielectric layer. The first conductive layer comprises first conductive traces that form a first portion of a first winding which, when energized, generates magnetic flux to a first phase of the motor or generator, as well as a first portion of a second winding which, when energized, generates magnetic flux for a second stage of the motor or generator.

[0004] In some embodiments, the planar composite structure (PCS) for use in an axial flux motor or generator comprises a dielectric layer, the first conductive layer located on a first side of the dielectric layer, and a second conductive layer located on a second side of the dielectric layer. The first conductive layer comprises first conductive traces that form a first portion of a winding which, when energized, generates magnetic flux to a first phase of the motor or generator. The second conductive layer comprises second conductive traces that form a second portion of the winding. The first portion of the winding is connected in series with the second portion of the winding, and the first and second portions of the winding are configured and arranged so that an equal amount of current flows through each of the first and second portions of the winding.

[0005] In some embodiments, the planar composite structure (PCS) for use in an axial flux motor or generator comprises a first conductive layer comprising first conductive traces, a second conductive layer comprising second conductive traces, a third conductive layer comprising comprises third conductive traces, and a fourth conductive layer comprising fourth conductive traces. The first conductive traces include first radial conductors that extend radially from a first radial distance to a second radial distance that is greater than the first radial distance, the second conductive traces include second radial conductors that extend radially from a first radial distance to a second radial distance, third conductor traces that include third radial conductors that extend radially from a first radial distance to a second radial distance, and fourth conductive traces that include fourth radial conductors that extend radially from a first radial distance to a second radial distance. The first radial conductors are electrically connected to corresponding second radial conductors by first blind or buried conductors, and the third radial conductors are electrically connected to corresponding fourth radial conductors by second blind or buried conductors.

[0006] In some embodiments, the planar composite structure (PCS) for use in an axial flux motor or generator comprises a subassembly comprising first conductive layers that include first radial conductors that extend radially from a first radial distance to a second radial distance that is greater than the first radial distance, first end-turn conductors, and second end-turn conductors. The first end loop conductors interconnect a first group of first radial conductors to form a first winding for a first stage of the axial flux motor or generator. The second end loop conductors interconnect a second group of first radial conductors to form a second winding for a second stage of the axial flux motor or generator. The first subset includes more second end loop conductors than first end loop conductors.

Brief Description of the Drawings

[0007] Figure 1A illustrates a "layer of turns" of a flat stator having a winding configuration such as that described in US Patent No. 7,109,625 ("the '625 patent");

[0008] Figure 1B illustrates a "connection layer" of a flat stator having a winding configuration such as that described in the '625 patent;

[0009] Figure 1C illustrates the bond layer shown in Figure 1B on top of the lap layer as shown in Figure 1A, with the hidden lines removed;

[00010] Figure 2 shows a selective view of a portion of a stator configuration having a stack of three six-layer subassemblies;

[00011] Figure 3 shows radial traces in a single angular position, through twelve conductive layers of a PCS, organized in three parallel groups connected by blind or buried vias;

[00012] Figure 4 shows internal end turns of the type described in the '625 patent, which are similar to the internal end turns shown in Figure 1A;

[00013] Figures 5A and 5B show an alternative arrangement of internal end turns in the two respective conductive layers of a PCS;

[00014] Figure 6 shows outer end turns of the type described in the '625 patent, which are similar to the outer end turns shown in Figure 1A;

[00015] Figures 7A and 7B show an alternative arrangement of outer end turns in the two respective conductive layers of a PCS;

[00016] Figure 8 shows inner end turns and outer end turns that interconnect radial traces to form a single spiral of a stator in accordance with the winding configuration taught by the '625 patent;

[00017] Figure 9 shows an alternative arrangement of inner and outer end turns for a single phase in a multi-layer plan view;

[00018] Figure 10A shows an expanded perspective view (on the z axis) of a subassembly that includes four conductive layers, with inner end turns and outer end turns corresponding to a phase selected for the sake of clarity;

[00019] Figure 10B illustrates the positions of the inner end turns and the outer end turns for a first stage within the subassembly shown in Figure 10A;

[00020] Figure 11A illustrates the positions of the inner end turns and the outer end turns for a second phase within the subassembly shown in Figure 10A;

[00021] Figure 11B illustrates the positions of the inner end turns and the outer end turns for a third phase within the subassembly shown in Figure 10A.

[00022] Figure 12A shows an expanded perspective view (on the z axis) of a set of three subsets, each similar to the subset shown in Figure 10A;

[00023] Figure 12B illustrates the positions of the inner end turns and the outer end turns for a first stage within the stack of three subassemblies shown in Figure 12A;

[00024] Figure 13A illustrates the positions of the inner end turns and the outer end turns for a second stage within the stack of three subassemblies shown in Figure 12A;

[00025] Figure 13B illustrates the positions of the inner end turns and the outer end turns for a third stage within the stack of three subassemblies shown in Figure 12A;

[00026] Figure 14 shows an expanded perspective view (on the z axis) of an example embodiment of a stator which employs serpentine windings such as those shown in Figure 9, and in which internal end turns of the type shown in Figures 5A and B and outer end turns of the type shown in Figures 7A and 7B are employed to establish all necessary winding connections for three phases in an assembly that includes only two conductive layers;

[00027] Figure 15A shows an expanded perspective view (on the z axis) of only those portions of the assembly shown in Figure 14 that correspond to a first phase of the stator;

[00028] Figure 15B shows the portions of the upper conductive layer shown in Figure 15A that contribute to the windings for the first phase;

[00029] Figure 15C shows the portions of the lower conductive layer shown in Figure 15A that contribute to the windings for the first phase;

[00030] Figure 16A illustrates how the windings for a second phase can pass through the assembly shown in Figure 14, with the portions of the assembly that correspond to the other two phases removed for illustration purposes;

[00031] Figure 16B illustrates how the windings for a third phase can pass through the assembly shown in Figure 14, with the portions of the assembly that correspond to the other two phases removed for illustration purposes;

[00032] Figures 17A and 17B illustrate an example of a process for forming a set/subset of multilayer PCS;

[00033] Figure 18A illustrates a system in which a PCS such as that described here is employed as a stator in an axial flux motor or generator; It is

[00034] Figure 18B illustrates an expanded view of the system shown in Figure 18A.

Detailed Description

[00035] The planar composite structure (PCS) that can be used, for example, as a stator in a motor or axial flux generator, can be constructed by forming multiple layers of conductive traces (conductive layers) on one or more layers of non-conductive dielectric material (dielectric layers). Examples of stators of this type are described in US Patent No. 7,109,625 ("the '625 patent"), US Patent No. 9,673,688, US Patent No. 9,673,684, and US Patent No. 9,800,109, the total contents of which are incorporated herein by reference in their entirety.

[00036] Figures 1A to 1C show plan views of two conductive layers of a flat stator having a winding configuration such as that described in the '625 patent. Together, the layers shown establish the internal and external "end turns" required for a single phase. Figure 1A shows a single "loop layer" L1 with inner end turns 102a and outer end turns 106 that arrange the radial traces 104 into spirals that are each associated with a pole pair. In this sixteen-pole stator, there are eight of the aforementioned spirals. In the example shown, the spirals spiral inward so that the end point of each spiral cannot be routed to the starting point of a subsequent spiral in the same layer. Said routing difficulty is described in more detail below in connection with Figure 8. Figure 1B shows a "bond layer" L2, which includes bonds 108 that serve to connect subsequent coils without interference with the loop layer L1. Each of the radial traces 104 in the L1 layer is connected to a corresponding (and parallel) radial trace 104 in the L2 layer, for example, using vias (not shown). The L2 bond layer also includes inner end turns 102b that are redundant with the inner end turns 102a in the L1 loop layer. Figure 1C shows the L2 bond layer on top of the L1 loop layer, with hidden lines removed. As seen, in said configuration, the outer end turns 106 and the connections 108 occupy some of the same space on the outer radius of the stator. Thus, a complete three-phase stator having a winding configuration such as that taught by the '625 patent requires a minimum of six conductive layers (i.e., three phases times two layers per phase). A balanced stator employing a winding layout therefore requires a multiple of six conductive layers. As used herein, a "balanced stator" refers to a stator in which the electrical load characteristics (in motor mode) or the electrical source characteristics (in generator mode) of each phase are equal to an electrical phase angle.

[00037] In relation to Figures 1A to 1C, it must be considered that certain details of the represented design, for example, particular structures and/or configurations for thermal management and loss reduction, such as those described in US patents 9,673,684 and 9,800. 109, are not described in the '625 document. Figures 1A through 1C, therefore, illustrate only the relative positions of radial traces, inner end turns, outer end turns, and connections as taught by the '625 patent, and not the structures or particular configurations that the '625 patent describes for these elements.

[00038] The stators were designed in which several three-phase balanced stator subassemblies (with six conductive layers each) were stacked on the same planar composite structure (PCS) and connected in parallel. Said designs can, for example, increase the current capacity and efficiency of the respective stator phases, because the current for each phase can be transported along parallel paths within the respective subassemblies. Figure 2 shows a selected view of a portion of a stator configuration having three six-layer subsets stacked in this manner, which focus on a single radial trace 204 while being connected in parallel through eighteen conductive layers (using routes 210). In the last layer L18, two adjacent radial traces 204a, 204b are also shown as a visual guide. The parallel arrangement of radial traces 204 in the active region, connected by vias 210, provides the opportunity to arrange internal and external loops and connections (as in Figures 1A to 1C) across multiple conductive layers. Since said eighteen radial strokes are parallel to each other, however, they can only contribute to a single loop structure.

[00039] Figure 3 shows a structure analogous to Figure 2, but related to the present description. In particular, Figure 3 shows radial traces 304 at a single angular position, through twelve conductive layers of a PCS. As shown, each radial trace 304 extends from a first radial distance R1 to a second radial distance R2 that is greater than the first radial distance R1. In this case, the radial traces 304 are organized into three parallel groups 312a, 312b, 312c connected by blind or buried vias 310. For manufacturing reasons, it is more convenient for each of these groups to have a multiple of two conductive layers. Unlike a stator constructed in accordance with the '625 patent, respective parallel groups 312a, 312b, 312c of radial traces 304 may be connected in series, thus allowing a higher turn count for each stator spiral. The turn count for the structure shown in Figure 3, comprising three groups of radial traces connected in parallel, may, for example, be three times greater than the turn count for the structure shown in Figure 2. An example of a stator implementation in which several groups of parallel-connected radial traces are connected in series in such a manner is described below in relation to Figures 12A, 12B, 13A and 13B.

[00040] Figure 4 shows a plurality of radial traces 404 that each extend from a first radial distance R1 to a second radial distance R2 that is greater than the first radial distance R1, as well as internal end turns 402 of the type described in the '625 patent, which are similar to the inner end loops 102 shown in Figure 1A. Said inner end turns 402, together with outer end turns 606 (shown in Figure 6), form all connections between respective radial traces 404 that are necessary to establish three turns per pole pair of a single phase. Thus, in accordance with the teachings of the '625' patent, a conductive layer that includes inner end turns 402 such as those shown in Figure 4 and outer end turns 606 such as those shown in Figure 6 (described below) is required. to connect a single phase. For a three-phase board constructed in accordance with the present configuration, a minimum of three of said conductive layers is required.

[00041] Figures 5A and 5B show an alternative arrangement of internal end turns 502 in the two respective conductive layers L3, L4. It should be noted that the layer numbers used here, for example, "L3," are provided only to permit identification of the various layers being described and are not intended to imply an order in which the various layers are positioned. In the illustrated arrangement, when radial traces 404 in layer L3 are connected in parallel with corresponding radial (and parallel) traces 404 in layer L4, for example, using vias (not shown in Figures 5A and 5B) similar to the vias 310 shown in Figure 3, inner end loop connections for all radial traces 404 shown in Figures 5A and 5B can be established only in two conductive layers. As explained in more detail below, said arrangement allows internal end turns 502 for multiple phases to be provided on the same conductive layer and also allows internal end turns 502 for the same phase to be distributed among multiple conductive layers. This is in contrast to the configuration of Figure 4, where the inner end turns 402 for only a single phase are provided in a given layer and the inner end turns 402 for a given phase are all included in the same conductive layer.

[00042] Additionally, as discussed in more detail below, in some implementations, one or both layers L3 and L4 may additionally include outer end turns, which may, for example, be arranged similar to the outer end turns 606 illustrated in FIG. 6 (described below). Examples of embodiments of this type are described below in relation to Figures 10A, 10B, 11A, 11B, 12A, 12B, 13A, and 13B. Alternatively, the outer end turns provided in layers L3 and L4 may be the same or similar to the outer end turns 706 described below in relation to Figures 7A and 7B. An example embodiment of the latter type is described below in relation to Figures 14, 15A, 15B, 15C, 16A, and 16B. Other configurations of outer end turns in one or both layers L3 and L4, or even configurations in which all outer end turns are included in layers other than layers L3 and L4, are also possible and contemplated.

[00043] Two complementary sets of inner end turns 502 are shown in Figures 5A and 5B, with a first set of inner end turns 502a, 502b, 502c, 502d, 502e and 502f being depicted in layer L3 in Figure 5A and a second set of inner end turns 502g, 502h, 502i, 502j, 502k, 502l being depicted in layer L4 in Figure 5B Comparing these complementary connections, and noting that end turns 502 for multiple phases can be provided on the same conductive layer and that the final turns 502 for a given phase may be distributed among several conductive layers, it is evident that all the inner end turning connections required for a three-phase stator can be achieved only in the two layers L3 and L4 illustrated. For example, a first phase may be supported by the inner end turns 502a and 502d in layer L3 in Figure 5A and the inner end turns 502h and 502k in layer L4 in Figure 5B, a second phase may be supported by the inner end turns 502b and 502e in layer L3 in Figure 5A and the inner end turns 502i and 502l in layer L4 in Figure 5B, and a third stage may be supported by the inner end turns 502c and 502f in layer L3 in Figure 5A and the inner end turns 502c and 502f in layer L3 in Figure 5A and the inner end 502g and 502j in layer L4 in Figure 5B. In such an implementation, since the inner edge turns 502 for each phase consume one-third of the L3 layer and one-third of the L4 layer, the inner edge turns 502 for each phase consume a total of two-thirds of a state layer. real in layers L3 and L4. In the example implementation shown, in addition, two minimum conductive layers are required to form inner-end loop connections for all three phases, and the conductive layer count must be a multiple of two for the stator to be balanced with respect to the inner end turns.

[00044] Additionally, it should be noted that, with the example configuration shown in Figures 5A and B, due to the fact that there are a total of twelve groups of end turns 502a to 502l available to establish the respective poles, each phase of a Three-phase stator employing said configuration should preferably have four poles. In other words, for a densely packed inner end turn configuration such as that shown in Figures 5A and B, the following equation is preferably satisfied for a three-phase stator (where "k" is an integer): 4*k = 3 * poles

[00045] Figure 6 shows outer end turns 606 of the type described in the '625 patent, which are similar to the outer end turns 106 shown in Figure 1A. Said outer end turns 606, together with inner end turns 402 (shown in Figure 4), form all connections between respective radial traces 404 that are necessary to establish three turns per pole pair of a single phase. Thus, in accordance with the teachings of the '625' patent, a layer including both outer end turns 606 such as those shown in Figure 6 and inner end turns 402 such as those shown in Figure 4 is necessary to connect a single phase. For a three-phase board constructed in accordance with the present configuration, a minimum of three of said conductive layers is required.

[00046] Similar to Figures 5A and 5B, Figures 7A and 7B show an alternative arrangement of outer end turns 706 in the two respective conductive layers L5, L6. In the illustrated arrangement, when radial traces 404 in layer L5 are connected in parallel with corresponding radial (and parallel) traces 404 in layer L6, for example, using vias (not shown in Figures 7A and 7B) similar to the vias 310 shown in Figure 3, the outer end loop connections for all radial traces 404 shown in Figures 7A and 7B can be established in two layers only. As explained in more detail below, said arrangement allows outer end turns 706 for multiple phases to be provided on the same conductive layer and also allows outer end turns 706 for the same phase to be distributed among multiple conductive layers. This is in contrast to the configuration of Figure 6, where the outer end turns 606 for only a single phase are provided in a given conductive layer and the outer end turns 606 for a given phase are all included in the same conductive layer.

[00047] Additionally, as discussed in more detail below, in some implementations, one or both layers L5 and L6 may additionally include internal end turns, which may, for example, be arranged similar to the internal end turns 402 illustrated in FIG. 4. Alternatively, the inner end loops provided in layers L5 and L6 may be the same or similar to the inner end loops 502 described above in relation to Figures 5A and 5B. An example embodiment of the latter type is described below in relation to Figures 14, 15A, 15B, 15C, 16A, and 16B. Other configurations of internal end turns in one or both layers L5 and L6, or even configurations in which all internal end turns are included in layers other than layers L5 and L6, are also possible and contemplated.

[00048] Regardless of the implementation, it must be considered that some mechanism will need to be used to somehow update the respective phases. In the example illustrated in Figures 7A and 7B, this is accomplished by configuring the groups of outer end turns 706b, 706c and 706h differently from the other groups of outer ends to establish the inputs 708a, 708b and 708c in the respective winding circuits. In other implementations, current may additionally or alternatively be introduced into one or more of the phases in some other way, such as from one or more other conductive layers, e.g., using solder vias/pads/pressure contacts or pins to conductive layers. dedicated connection, connect the wires directly to the pads within the outer end turns 706, or another similar technique.

[00049] Additionally, it should be noted that, in some implementations, current may additionally or alternatively be fed to the respective phases from the internal region of the stator, with one or more internal groups of end turns 402, 502 such as shown in Figures 4 and 5 being configured differently than the other internal groups of end turns to allow inputs similar to inputs 708a, 708b, and/or 708c, but instead of being located in an internal region of the stator. Furthermore, in some implementations, rather than having an axis that passes through the central region of the stator, a rotor may instead rotate "outside" the stator, for example, an annular or tubular rotor structure could surround and rotate in around the stator. This implementation may make sense, for example, in a modification in which the current is fed to the respective phases from the internal region of the stator.

[00050] Two complementary sets of outer end turns 706 are shown in Figures 7A and 7B, with a first set of outer end turns 706a, 706b, 706c, 706d, 706e and 706f being illustrated in layer L5 in Figure 7A and a second set of outer end turns 706g, 706h, 706i, 706j, 706k and 706l being illustrated in layer L6 in Figure 7B. By comparing these complementary connections, and appreciating that the outer end turns 706 for several phases may be provided on the same conductive layer and that the outer end turns 706 for a given phase may be distributed among the various conductive layers, it is evident that all the outer end turns connections required for a three-phase stator can be obtained only in the two layers L5 and L6 illustrated. For example, a first phase may be supported by the outer end turns 706a and 706d in layer L5 in Figure 7A and the outer end turns 706h and 706k in layer L6 in Figure 7B, a second phase may be supported by the outer end turns 706b and 706e on layer L5 in Figure 7A and the outer end turns 706i and 706l on layer L6 in Figure 7B, and a third stage may be supported by outer end turns 706c and 706f on layer L5 in Figure 7A and the outer end turns 706c and 706f on layer L5 in Figure 7A and the outer end 706g and 706j in layer L6 in Figure 7B. In such an implementation, since the outer edge turns 706 for each phase consume one-third of the L5 layer and one-third of the L6 layer, the outer edge turns 706 for each phase consume a total of two-thirds of a viable state layer. real in layers L5 and L6. In the example implementation shown, additionally, two minimum conductive layers are required to form the outer end turn connections for all three phases, and the conductive layer count must be a multiple of two for the stator to be balanced relative to around the outer edge.

[00051] Figure 8 shows the inner end turns 802 and the outer end turns 806 that interconnect radial traces 804 to form a single spiral of a stator in accordance with the winding configuration taught by the '625 patent. The illustrated spiral can be seen to either start at point 808 and spiral "in" at point 810, or start at point 810 and spiral "out" at point 808. Note that, in said structure, there are four end turns internal 802 but only three outer end turns 806. The "missing" outer end turn 806 cannot be routed in the same layer as the other turns, due to the fact that it needs to establish a connection from the inside of the spiral (e.g. point 810) to the outside of the next spiral, or vice versa. As this type of connection proceeds around the stator, it circles the center point of the stator only once.

[00052] Figure 9 shows an alternative arrangement of inner and outer end turns for a single phase in a plan view of multiple conductive layers. Three turns are made on the layers shown. In some implementations, internal end turns 502 such as those shown in Figures 5A and 5B may be employed, and said internal end turns 502 may be distributed across two (or more) conductive layers. In some implementations, for example, the inner end turns illustrated in Figure 9 may include two groups of inner end turns 502 from one layer (e.g., inner end turns 502b and 502e in the L3 layer shown in Figure 5A). and two groups of inner end turns 502 from another layer (e.g., inner end turns 502i and 502l in layer L4 shown in Figure 5B). As discussed above in relation to Figures 5A and 5B, the use of inner end loops 502 from two or more conductive layers can allow the formation of a complete set of inner end loop connections for a single phase. Alternatively, in some implementations, some or all of the inner end turns illustrated in Figure 9 may be of the type shown in Figure 4, i.e., such as inner end turns 402, and may be arranged in a common conductive layer.

[00053] In some implementations, some or all of the outer end turns shown in Figure 9 may be of the type shown in Figure 6, i.e., such as outer end turns 606, and may be arranged in a common conductive layer. Alternatively, some or all of the illustrated outer end turns may be of the type shown in Figure 7, i.e., such as outer end turns 706, and may be distributed across two (or more) conductive layers. In some implementations, for example, the outer end turns illustrated in Figure 9 may include two groups of outer end turns 706 from a conductive layer (e.g., outer end turns 706a and 706d in layer L5 shown in Figure 7A). ) and two groups of outer end turns 706 from another conductive layer (e.g., outer end turns 706h and 706k in layer L6 shown in Figure 7B). As discussed above in relation to Figures 7A and 7B, the use of outer end loops 706 from two or more conductive layers can allow the formation of a complete set of outer edge loop connections for a single phase.

[00054] Regardless of implementation, it should be considered that, contrary to Figure 8, for most groups of end turns, the number of turns within a given group of outer turns 606, 706 is equal to the number of turns within of an adjacent group of internal end turns 402, 502 and vice versa. Tracing the upper right terminal connections 902, the radial traces 404, inner end turns 402, 502 and outer end turns 606, 706 form a serpentine pattern that is capable of being routed in a single conductive layer. In the implementation shown in Figure 8, on the contrary, only unconnected windings could be routed in a single conductive layer. As shown in Figure 9, the serpentine pattern starting at terminal 902 and ending at terminal 904 wraps around a center point 906 of the stator three times (or turns).

[00055] Figures 10A, 10B, 11A, 11B, 12A, 12B, 13A, and 13B illustrate examples of stator embodiments that employ serpentine windings such as those shown in Figure 9, and in which internal end turns 502 of the type shown in Figures 5A and B and outer end turns 606 of the type shown in Figure 6 are employed to establish winding connections to one or more subassemblies each including four conductive layers. Features of a single one of said subset S1 are illustrated in Figures 10A, 10B, 11A, and 11B, and features of a stacked set of three of said subsets S1, S2, and S3 are illustrated in Figures 12A, 12B, 13A, and 13B . In the example shown in said Figures, for each subset S1, S2, and S3 that is illustrated, each of the radial connectors 404 on a given conductive layer of that subset is connected to corresponding (and parallel) radial connectors 404 on the other conductive layers. of the same subassembly using vias 310, in the manner illustrated in Figure 3. An illustrative technique for forming multilayer PCS assemblies/subassemblies such as those shown is described below in relation to Figures 17A and 17B.

[00056] Figure 10A shows an expanded perspective view (on the z axis) of a subassembly S1 having four conductive layers, with inner end turns 502b, 502e, 502i, 502l and outer end turns 606 that correspond to a selected phase for the sake of greater clarity. The positions of additional inner end turns 502 and outer end turns 606 that may be incorporated within the structure of Figure 10A to establish the other two phases of a three-phase stator are illustrated in Figures 11A-11B below. Figure 10B is similar to Figure 10A but, for illustration purposes, has additional portions of subset S1 that correspond to the other two phases removed. Figure 10B thus illustrates how the windings for a single phase of a three-phase stator can pass through a subassembly S1 having four conductive layers.

[00057] Similar to Figure 10B, Figures 11A to 11B illustrate how the windings of the remaining two phases can operate through the subset S1 shown in Figure 10A, with the portions of the subset that correspond to the other two phases removed for illustration purposes. Thus, Figure 10B illustrates the positions of the inner end turns 502b, 502e, 502i, 502l and the outer end turns 606 for a first phase within the subassembly S1, Figure 11A illustrates the positions of the inner end turns 502a, 502d, 502h, 502k and the outer end turns 606 for a second stage within the subassembly S1, and Figure 11B illustrates the positions of the inner end turns 502c, 502f, 502g, 502j and the outer end turns 606 for a third phase within subset S1.

[00058] The inner end turns 502b, 502e, 502i, 502l for the first phase illustrated in Figures 10A and 10B appear in multiplicity of two across four conductive layers, with the inner end turns 502b and 502e appearing in two of the four layers illustrated and inner end loops 502i and 502l appearing in the remaining two layers. The same also applies to the internal end turns 502 for the other two phases illustrated in Figures 11A and 11B. That is, for the second phase illustrated in Figure 11A, the inner end loops 502a, 502d, 502h, 502k appear in multiplicity of two over the four layers, with the inner end loops 502a and 502d appearing in two of the four illustrated layers. and the inner end turns 502h and 502k appearing in the remaining two layers and for the third phase illustrated in Figure 11B, the inner end turns 502c, 502f, 502g, 502j appear in multiplicity of two in the four layers, with the inner end turns 502h and 502k appearing in the remaining two layers inner end loops 502c and 502f appearing in two of the four illustrated layers and inner end loops 502g and 502j appearing in the remaining two layers. Therefore, for all three phases of the subset S1 shown in Figures 10A, 10B, 11A and 11B, the inner ends 502 appear with a multiplicity of two over the four conductive layers and are balanced (equal for each phase) because the subset S1 has a multiple of two conductive layers.

[00059] For the particular phase shown in Figures 10A and 10B, that is, the first phase, the outer end turns 606 also appear with a multiplicity of two over the four illustrated layers. For said phase, the outer end turns 606 occupy two of the four conductive layers. The outer end turns 606 for the other two phases (shown in Figures 11A and 11B) are in the other two conductive layers, but without redundancy. That is, the outer end turns 606 for the second phase (shown in Figure 11A) appear only in a single conductive layer, as do the outer end turns 606 for the third phase (shown in Figure 11B). Thus, the subassembly S1 shown in Figures 10A, 10B, 11A and 11B has all the necessary connections of a three-phase stator, but is unbalanced due to the unequal redundancy of the outer end turns 606 over the phases.

[00060] Figure 12A shows an expanded perspective view (on the z axis) of a set of three subsets S1, S2, and S3, each of which is similar to the subset shown in Figure 10A. In some embodiments, two or more of the respective subassemblies may be laminated together to form a single PCS. As in Figure 10A, Figure 12A shows inner end turns 502 and outer end turns 606 associated with only one of the three phases for the sake of clarity. The positions of additional inner end turns 502 and outer end turns 606 that can be incorporated into the structure of Figure 12A to establish the other two phases of a three-phase stator are illustrated in Figures 13A to -13B below.

[00061] Figure 12B is similar to Figure 12A but, for illustration purposes, has additional portions of subsets S1, S2, and S3 that correspond to the other two phases removed. Figure 12B thus illustrates how the windings for a single phase of a three-phase stator can pass through a stacked assembly of three subassemblies S1, S2, and S3, with each subassembly having four conductive layers. Subassemblies S1, S2, S3 can be electrically connected, either in parallel or in series, via direct paths 1202a, 1202b, 1202c, 1204a, 1204b, 1204c, 1206a, 1206b, and 1206c. In the example shown, the windings of the three subassemblies S1, S2, and S3 are connected in series so that the turn count for each phase of the entire assembly is three times greater than the turn count of any of the individual subassemblies S1. , S2, and S3.

[00062] The manner in which current can flow through and between the windings of subassemblies S1, S2, and S3 for the phase illustrated in Figure 12B will now be explained. Although not described separately, it should be noted that similar paths can be followed for the windings of the other two phases (shown in Figures 13A and 13B - described below), but using different groups of direct paths 1202, 1204, and 1206. For phase illustrated in Figure 12B, current can flow into the windings of subassembly S1 from direct path 1202b. The current can then leave the windings of subassembly S1 through the conductive trace 1208. Current from the conductive trace 1208 can then flow through the direct path 1204b to the conductive trace 1210, where it can enter the windings of the subassembly S2. Current may then exit the subassembly windings S2 via conductive traces 1212a and 1212b. The current from the conductive traces 1212a, 1212b can then flow through the direct path 1206b to the conductive traces 1214a and 1214b, where it can enter the windings of the subassembly S3. Current can then exit the S3 subassembly windings and flow into a neutral conductor, along with the currents from the other two phases (shown in Figures 13A and 13B).

[00063] Similar to Figure 12B, Figures 13A to 13B illustrate how the windings of the remaining two phases can function in the three subassemblies S1, S2, and S3 shown in Figure 12A, with the portions of the subassemblies that correspond to the other two phases removed by illustration questions. Thus, Figure 12B illustrates the positions of the inner end turns 502b, 502e, 502i, and 502l and the outer end turns 606 for a first phase within the stack of three subassemblies S1, S2, and S3, Figure 13A illustrates the positions of the inner end turns 502a, 502d, 502h, and 502k and the outer end turns 606 for a second phase within the stack of three subassemblies S1, S2, and S3, and Figure 13B illustrates the positions of the end turns inner 502c, 502f, 502g, and 502j and the outer end turns 606 to a third stage within the stack of three subassemblies S1, S2, and S3.

[00064] Each subset S1, S2, and S3 comprises four conductive layers, such as Figure 10A, but the layer with outer end turns 606 of the multiplicity of two in each subset is different. Thus, for the phase illustrated in Figures 12A and 12B, the top subassembly S1 has two parallel layers of outer end turns 606, but the other two subassemblies S2 and S3 do not; for the stage illustrated in Figure 13A, the bottom subset S3 has two parallel layers of outer end turns 606, but the other two subsets S1 and S2 do not; and for the stage illustrated in Figure 13B, the middle subset S2 has two parallel layers of outer end turns 606, but the other two subsets S1 and S3 do not. Thus, the stacked assembly shown by the combination of Figures 12A, 12B, 13A and 13B is arranged so that each of the three phases has the same number of layers connected in parallel or in series of external turns 606, in addition to having the same number of layers connected in parallel or in series of internal end turns 502, thus making the assembly as a whole balanced.

[00065] Figures 14, 15A, 15B, 15C, 16A, and 16B illustrate an example embodiment of a stator which employs serpentine windings such as those shown in Figure 9, and in which internal end turns 502 of the type shown in Figures 5A and B and outer end turns 706 of the type shown in Figures 7A and 7B are employed to establish all necessary winding connections for three phases in an assembly that includes only two conductive layers. In the example shown in said Figures, each of the radial connectors 404 on the upper conductive layer is connected to a corresponding radial (and parallel) connector 404 on the lower conductive layer using vias 1410, which are similar to the vias 310 shown in Figure 3.

[00066] Figure 15A shows an expanded perspective view (on the z axis) of only those portions of the assembly shown in Figure 14 that correspond to a first phase of the stator. As shown, the first stage may employ inner end turns 502b, 502e, 502i, 502l shown in Figures 5A and 5B, and outer end turns 706a, 706d, 706h, and 706k shown in Figures 7A and 7B. Figure 15A thus illustrates how the windings for a single phase of a three-phase stator can pass through the assembly shown in Figure 14. Figures 15B and 15C show, respectively, the portions of the upper and lower conductive layers shown in Figure 15A that contribute to the windings for the first phase.

[00067] Similar to Figure 15A, Figures 16A and 16B illustrate how the windings of the remaining two phases can pass through the assembly shown in Figure 14, with the portions of the assembly that correspond to the other two phases removed for illustration purposes. As shown in Figure 16A, a second stage may employ inner end turns 502a, 502d, 502h, 502k shown in Figures 5A and 5B, and the outer end turns 706c, 706f, 706g, and 706j shown in Figures 7A and 7B. As shown in Figure 16B, the third stage may employ inner end turns 502c, 502f, 502g, 502j shown in Figures 5A and 5B, and the outer end turns 706b, 706e, 706i, and 706l shown in Figures 7A and 7B.

[00068] The two conductive layer implementations shown in Figures 14, 15A, 15B, 16A, and 16B represent the practical limit of reducing the number of layers required for a complete three-phase stator. It should be noted, however, that for said configuration some mechanism will be required to establish an electrical connection from a drive circuit (not shown) to a location within the serpentine winding for each phase. For example, with reference to Figure 15A, an electrical connection will have to be made from said drive circuit to track 1410b (or other conductor) so as to allow the drive circuit to establish a complete circuit for the first phase . An electrical connection to the other end of the serpentine winding for the first phase can be established via the direct path 1402b shown in Figure 15A. Similarly, with reference to Figures 16A and 16B, electrical connections will have to be made from a drive circuit to tracks 1410c and 1410a (or other conductors), respectively, in order to allow the drive circuit to establish circuits. complete for the second and third phases. Electrical connections to the other ends of the serpentine windings for the second and third phases can be established via the through paths 1402c and 1402a shown in FIGS. 16A and 16B, respectively.

[00069] Said electrical connections may be established using any of a number of mechanisms, including via solder vias/pads/pressure contacts or pins to dedicated connection layers, connecting wires directly to the pads within the outer end turns or otherwise. similar technique. The ultimate advantage of a two-layer approach such as that illustrated in Figures 14, 15A, 15B, 15C, 16A, and 16B - assuming that no additional layers are required to make an electrical connection - is that the number of turns per layer can be increased by a factor of three in a configuration such as that described in '625, or by a factor of two over the configuration described above in connection with Figures 10A, 10B, 11A, 11B, 12A, 12B, 13A and 13B. If additional layers are required, for example to build a complete stator with neutral connection and terminals outside the radius of the outer end turns, this advantage diminishes. Additionally, high-density outer edge turns can affect the ability to use thermal resources connected directly to the active region.

[00070] Although not shown in the drawings, it should also be noted that it is also possible to stack two or more sets similar to those shown in Figures 14, 15A, 15B, 15C, 16A and 16B and connect the windings of these sets together, in parallel or in series. In some implementations, for example, the via 1410a shown in Figure 15A may be connected to a serpentine winding "input" of another similar assembly with two conductive layers, for example, using one of the connection techniques described in the previous paragraph, establishing thus a series connection with additional turns for the first phase. In some embodiments, said serpentine winding in the second set may traverse a similar serpentine path, e.g., counterclockwise, as the first set, but may instead wind outward toward the turns of outermost end turn 706. An additional electrical connection could also be established from the outermost end turn of the second set to an input of yet another serpentine winding in another set with only two conducting layers, and that winding in Additional serpentine could, for example, traverse a similar serpentine path, e.g., counterclockwise as the second set, but may again coil "inward", similar to the configuration of Figure 15A. The said technique of winding "in" and then winding "out" on the respective layers connected in series can be repeated countless times to keep increasing the turn count of the respective phases. In some embodiments, two or more of said respective assemblies may be laminated together to form a single planar composite structure (PCS).

[00071] Figures 17A and 17B illustrate an example of a process for forming a multilayer PCS set/subset 1700. In the example shown, the PCS set/subset 1700 includes four conductive layers CL1, CL2, CL3, and CL4, and three non-conductive dielectric layers DL1, DL2, and DL3. It should be noted, however, that the described technique can additionally or alternatively be used to form PCS subsets and/or subsets with different numbers of layers.

[00072] In some embodiments, two or more dielectric layers DL1, DL2, DL3 can be interspersed with multiple conductive layers CL1, CL2, CL3, CL4 and laminated together. The patterns of conductive traces in each conductive layer CL1, CL2, CL3, CL4 may be arranged to form conductors for one or more circuit elements (e.g., portions of the stator windings) and may be formed of an electrically conductive material, such as like copper. Each conductive layer CL1, CL2, CL3, CL4 can be mechanically supported by at least one dielectric layer DL1, DL2, DL3. The dielectric layers may be formed from a non-conductive material, such as fiberglass. Each dielectric layer DL1, DL2, DL3 can thus electrically isolate a respective pair of the conductive layers CL1, CL2, CL3, CL4.

[00073] The conductor patterns of each conductive layer CL1, CL2, CL3, CL4 can be produced by various methods, including, but not limited to, engraving, stamping, spraying, cutting or machining. In some implementations, for example, conductor patterns may be chemically etched onto each side of a plurality of two-sided circuit boards, with each such circuit board including a glass fiber sheet (e.g., DL1 dielectric layer or DL3 in Figure 17A) arranged between two copper sheets (for example, CL1 and CL2 or CL3 and CL4 in Figure 17A). Several double-sided circuit boards formed in this manner can then be stacked together, with a dielectric (e.g., fiberglass) sheet (e.g., dielectric layer DL2 in Figure 17A) being disposed between each pair. The stacked double-sided circuit boards and fiberglass sheets can then be laminated together using heat and pressure to form a multi-board array, such as that shown in Figure 17B. As noted, the resulting PCS can, for example, be used as a stator for an axial flux motor or generator.

[00074] In some embodiments, PCS of the type described above may employ copper sheets that are thicker than the copper sheets used in most commonly produced circuit boards. In some implementations, for example, the copper sheets may have thicknesses ranging from 0.004 inches to 0.007 inches. Holes 1702 may be drilled at precise locations through one or more (or all) of the multiple circuit boards of a PCS 1700 and the inner walls of the holes may be coated with a conductive material such as copper. Galvanized holes, also known as vias (e.g., blind or buried vias 310 shown in Figure 3 or vias 1202a, 1202b, 1202c, 1204a, 1204b, 1204c, 1206a, 1206b, and 1206c shown in Figures 12A) and can act as conductors between layers that electrically interconnect the conductive traces in different conductive layers of the PCS. It should be considered, however, that other types of interlayer conductors may be used additionally or alternatively, including, but not limited to, holes filled with conductive material, metal pins, crimp points, spot welds, or wires. The various conductors in the different layers of the PCS can be connected together in series and/or in parallel by these vias or other interlayer conductors.

[00075] As shown in Figure 17B, the PCS 1700 may additionally include a central hole 1704 to accommodate a shaft of a rotor of an axial flux motor or generator, as described below.

[00076] The assemblies and/or subassemblies described here can be employed in any engine or generator known or developed in the future, which includes the axial flow engines/generators described in the '625 patent, as well as the engines and generators described in the U.S. Pat. No. 9,673,688, US Patent No. 9,673,684, and/or US Patent No. 9,800,109, the entire contents of all of which are incorporated by reference above.

[00077] Figure 18A shows an example of a system 1800 that employs a flat composite stator 1810 in an assembly with rotor components 1804a and 1804b, shaft 1808, screws 1802, wires 1814, and controller 1812. An expanded view showing the said components and means for assembling the same is shown in Figure 18B. The pattern of magnetic poles in the permanently magnetized portions 1806a, 1806b of the rotor assembly is also evident in the expanded view of Figure 18B. Figure 18A is an example of an embodiment in which the electrical connections 1814 are taken on the outer radius of the PCS 1810, and the stator is mounted on a frame or box on the outer periphery. Another useful configuration, the "out-of-channel" configuration, involves mounting the stator on the inner radius, making the electrical connections 1814 on the inner radius, and replacing the shaft 1808 with an annular ring that separates the rotor halves. It is also possible to configure the system with just one magnet, 1806a or 1806b, or interpose several stators between sets of successive magnets. The 1814 wires can also transmit information about the position of the rotor based on readings from Hall effect or similar sensors mounted on the stator. Not shown, but for a similar purpose, an encoder connected to shaft 1808 may provide position information to controller 1812.

[00078] The system 1800 in Figures 18A and 18B can function as a motor or a generator, depending on the operation of the controller 1812 and the components connected to the shaft 1808. As a motor system, the controller 1812 operates the switches so that the currents in the stator 1810 create a torque around the shaft, due to the magnetic flux in space from magnets 1806a, 1806b connected to shaft 1808. Depending on the configuration of controller 1812, the magnetic flux in space and/or the position of the rotor can be measured or estimated to operate the switches to achieve torque output on shaft 1808. As a generator system, a mechanical rotation power source connected to shaft 1808 creates voltage waveforms at stator terminals 1812. Said voltages may be applied directly to a load, or may be rectified with a three-phase (or polyphase) rectifier within the 1812 controller. The 1812 rectifier implementation may be "self-switched" using diodes in generator mode, or may be constructed using the motor controller controlled switches, but operated so that the shaft torque opposes the torque provided by the mechanical source and the mechanical energy is converted into electrical energy. Thus, an identical configuration in Figure 18A can function not only as a generator, but also as a motor, depending on how the controller 1812 is operated. Additionally, the controller 1812 may include filter components that mitigate switching effects, reduce EMI/RFI from the wires 1814, reduce losses, and provide additional flexibility in the power supplied to or sent from the controller.

[00079] Having thus described various aspects of at least one embodiment of the present invention, it should be appreciated that various changes, modifications and improvements will readily occur to those skilled in the art. Such changes, modifications and improvements shall form part of the present description and shall be within the spirit and scope of the invention. Therefore, the above description and drawings are by way of example only.

[00080] Various aspects of the present invention can be used alone, in combination or in a variety of arrangements not specifically discussed in the embodiments described below and, therefore, are not limited in the present application to the details and arrangement of the components set out in the previous description or illustrated in the drawings. For example, aspects described in one embodiment may be combined in any way with aspects described in other embodiments.

[00081] Furthermore, the present invention can be incorporated as a method, of which an example has been provided. The acts performed as part of the method may be ordered in any suitable manner. Accordingly, embodiments may be constructed in which acts are performed in an order different from that illustrated, which may include performing some acts simultaneously, even if shown as sequential acts in the illustrative embodiments.

[00082] The use of ordinal terms such as "first", "second", "third" etc. in claims to modify a claim element, by itself does not imply any priority, precedence or order of one claim element over another or the temporal order element in which the acts of a method are performed, but are used only as labels for distinguishing a claimed element with a given name from another element with the same name (but for use of the term ordinal) to distinguish the elements of the claim.

[00083] Furthermore, the phraseology and terminology used herein are used for descriptive purposes and should not be considered limiting. The use of "including", "comprising" or "having", "containing", "involving" and variations herein is intended to cover the items listed below and their equivalents, as well as additional items.

Claims (31)

1. Flat composite structure (PCS) for use in an axial flux motor or generator, comprising: a dielectric layer (DL); and a first conductive layer (CL) disposed on a first side of the dielectric layer (DL), the first conductive layer (CL) comprising first conductive traces including: first radial conductors (404), each of the first radial conductors (404) extending radially at least between a first radial distance (R1) and a second radial distance (R2) that is greater than the first radial distance (R1), and first conductive end turns (502, 606, 706), each of the first conductive end turns interconnecting a respective pair of the first radial conductors (404), the first conductive end turns (502, 606, 706) including a first inner end turn (502) and a second inner end turn (502 ), the first inner end loop (502) electrically interconnects portions of a first pair of first radial conductors (404) at the first radial distance (R1), and the second inner end loop (502) electrically interconnects portions of a second pair of the first radial conductors (404) in the first radial distance (R1), characterized by the fact that: the first conductive traces forming: a first portion of a first winding which, when energized, generates magnetic flux for a first phase of the motor or generator, the first portion of the first winding including the first inner end turn (502), and a first portion of a second winding which, when energized, generates magnetic flux to a second phase of the motor or generator, the first portion of the second winding including second inner end turn (502); a second conductive layer (CL) disposed on a second side of the dielectric layer (DL), the second conductive layer (CL) comprising second conductive traces that include second radial conductors (404), wherein each of the second radial conductors (404) extending radially at least between the first radial distance (R1) and the second radial distance (R2); and pathways (310) through the dielectric layer (DL), each of the first radial conductors (404) being electrically connected through at least one respective via (310) to a corresponding one of the second radial conductors (404). 2. Flat composite structure (PCS), according to claim 1, characterized by the fact that: the first winding comprises a second portion electrically connected in series with the first portion of the first winding; the first conducting end loops (502, 606, 706) further comprise a first outer end loop (606, 706); the first outer end loop (606, 706) electrically interconnects a portion of one of the first pair of first radial conductors (404) at the second radial distance (R2) and a portion of the other of the first radial conductors (404) at the second radial distance (R2); and the second portion of the first winding comprises the first outer end turn (606, 706). 3. Flat composite structure (PCS) according to claim 2, characterized in that the first inner end turn (502) and the first outer end turn (606, 706) are arranged so that the first and the second portions of the first winding form a serpentine pattern. 4. Flat composite structure (PCS) according to claim 2 or 3, characterized in that: the second conductive traces form a third portion of the first winding, wherein the third portion of the first winding is connected in series with the second portion of the first winding. 5. Flat composite structure (PCS) according to claim 4, characterized by the fact that the second conductive traces further comprise: second conductive end turns (502, 606, 706), each of the second conductive end turns ( 502, 606, 706) interconnecting a respective pair of second radial conductors (404). 6. Flat composite structure (PCS), according to claim 5, characterized by the fact that: the second conductive end turns (502, 606, 706) comprise a third internal end turn (502); the third inner end loop (502) electrically interconnects portions of a first pair of second radial conductors (404) at the first radial distance; and the third portion of the first winding comprises the third inner end turn (502). 7. Flat composite structure (PCS), according to claim 5 or 6, characterized by the fact that: the first winding comprises a fourth portion electrically connected in series with the third portion of the first winding; the first conductive end loops (502, 606, 706) further comprise a second outer end loop; the second outer end loop (606, 706) electrically interconnects portions of a second pair of the second radial conductors (404) at the second radial distance (R2); and the fourth portion of the first winding comprises the second outer end turn (606, 706). 8. Flat composite structure (PCS) according to claim 1, characterized by the fact that: the second conductive traces form a second portion of the first winding, wherein the second portion of the first winding is connected in series with the first portion of the first winding. 9. Flat composite structure (PCS) according to claim 8, characterized by the fact that the second conductive traces further comprise: second conductive end turns (502, 606, 706), each of the second conductive end turns ( 502, 606, 706) interconnecting a respective pair of second radial conductors (404). 10. Flat composite structure (PCS), according to claim 9, characterized by the fact that: the second conductive end turns (502, 606, 706) comprise a third internal end turn (502); the third inner end loop (502) electrically interconnects portions of a first pair of second radial conductors (404) at the first radial distance (R1); and the second portion of the first winding comprises the third inner end turn (502). 11. Flat composite structure (PCS), according to claim 10, characterized by the fact that: the first winding comprises a third portion electrically connected in series with the second portion of the first winding; the first conducting end loops (502, 606, 706) further comprise a first outer end loop (606, 706); the first outer end loop (606, 706) electrically interconnects portions of a second pair of the second radial conductors (404) at the second radial distance (R2); and the third portion of the first winding comprises the first outer end turn (606, 706). 12. Flat composite structure (PCS) according to claim 1, characterized by the fact that: the first conductive end turns (502, 606, 706) comprise a first outer end turn (606, 706) and a second outer end turn (606, 706); the first outer end loop (606, 706) electrically interconnects portions of a first pair of first radial conductors at the second radial distance (R2); the second outer end loop (606, 706) electrically interconnects portions of a fourth pair of the first radial conductors at the second radial distance (R2); the first portion of the first winding comprises the first outer end turn (606, 706); It is. the first portion of the second winding comprises the second outer end turn (606, 706). 13. Flat composite structure (PCS), according to claim 6, characterized by the fact that: the first winding comprises a fourth portion electrically connected in series with the third portion of the first winding; the second conductive end loops (502, 606, 706) further comprise a second outer end loop (606, 706); the second outer end loop (606, 706) electrically interconnects the portion of one of the first pair of second radial conductors (404) at the second radial distance (R2) and the portion of the other of the second radial conductors (404) at the second radial distance (R2); and the fourth portion of the first winding comprises the second outer end turn (606, 706). 14. Flat composite structure (PCS) according to any one of claims 1 to 13, characterized in that the first conductive traces are arranged so that the first portion of the first winding forms a serpentine pattern 15. Flat composite structure (PCS), according to any one of claims 1 to 14, characterized by the fact that: the first winding comprises a first serpentine winding; and the second winding comprises a second serpentine winding. 16. Flat composite structure (PCS) according to any one of claims 1 to 15, characterized by the fact that: the first radial conductors comprise at least first, second, third, fourth, fifth and sixth radial conductors, the second conductor radial being angularly positioned between the first and third radial conductors and the third radial conductor being angularly positioned between the second and fourth radial conductors; the second radial conductors (404) comprise at least seventh, eighth, ninth and tenth radial conductors; the tracks (310) comprise a first track (310) interconnecting the first and seventh radial conductors, a second track (310) interconnecting the second and eighth radial conductors, a third track (310) interconnecting the third and ninth radial conductors and a fourth track (310) interconnecting the fourth and tenth radial conductors; the second conductive traces further comprise second conductive end loops (502, 606, 706), each of the second conductive end loops (502, 606, 706) interconnecting a respective pair of second radial conductors (404), the second conductive end loops (502, 606, 706) conductive end (502, 606, 706) including a third inner end loop (502) interconnecting portions of the seventh and ninth radial conductors first radial distance (R1); the second conductive traces form a second portion of the first winding, the second portion of the first winding including the third inner end turn (502); the first inner end loop interconnects portions of the fifth and sixth radial conductors at the first radial distance (R1); and the second inner end loop interconnects portions of the second and fourth radial connectors at the first radial distance (R1). 17. Flat composite structure (PCS) for use in an axial flux motor or generator, comprising: a dielectric layer (DL); a first conductive layer located on a first side of the dielectric layer (DL), the first conductive layer comprising first conductive traces including: first radial conductors, each of the first radial conductors extending radially at least between a first radial distance (R1) and a second radial distance (R2) that is greater than the first radial distance (R1), and first conductive end turns (502, 606, 706), each of the first conductive end turns (502, 606, 706) interconnecting a respective pair of first radial conductors, the first conductive end turns (502, 606, 706) comprising a first inner end turn interconnecting portions of a first pair of first radial conductors at the first radial distance (R1), characterized by the fact which further comprises: a second conductive layer located on a second side of the dielectric layer (DL), the second conductive layer comprising second conductive traces that include second radial conductors (404), each of the second radial conductors (404) extending radially at least between the first radial distance (R1) and the second radial distance (R2), and second conductive end turns (502, 606, 706), each of the second conductive end turns (502, 606, 706) interconnecting a respective pair of second radial conductors (404), the second conductive end loops (502, 606, 706) comprising a second inner end loop interconnecting portions of a first pair of second radial conductors (404) at the first radial distance (R1) ; and pathways (310) through the dielectric layer (DL), each of the first radial conductors being electrically connected through at least one respective via (310) to a corresponding one of the second radial conductors; wherein no conductive trace in the first conductive layer interconnects the portions of the first pair of second radial conductors (404) at the first radial distance (R1), no conductive trace in the second conductive layer interconnects the portions of the first pair of first radial conductors at the first distance radial (R1), the first conductive traces form a first portion of a winding which, when energized, generates magnetic flux to a first phase of the motor or generator, the first portion of the winding comprising the first inner end turn, the second conductive traces form a second portion of the winding, the second portion of the winding including the second inner end turn, the first portion of the winding is connected in series with the second portion of the winding, and the first and second portions of the winding are configured and arranged accordingly. so that an equal amount of current flows through each of the first and second portions of the winding. 18. Flat composite structure (PCS), according to claim 17, characterized by the fact that: the winding further comprises a third portion electrically connected in series between the first winding portion and the second winding portion; the first conducting end loops (502, 606, 706) further comprise a first outer end loop (606, 706); the first outer end loop (606, 706) electrically interconnects a portion of one of the first pair of first radial conductors at the second radial distance (R2) and a portion of the other of the first radial conductors at the second radial distance (R2); and the third portion of the winding comprises the first outer end turn (606, 706). 19. Flat composite structure (PCS), according to claim 18, characterized by the fact that: the winding comprises a fourth portion electrically connected in series with the second portion of the winding; the first conducting end loops (502, 606, 706) further comprise a second outer end loop (606, 706); the second outer end loop (606, 706) electrically interconnects portions of a second pair of the second radial conductors (404) at the second radial distance (R2); and the fourth portion of the winding comprises the second outer end turn (606, 706). 20. Flat composite structure (PCS), according to claim 18, characterized by the fact that: the winding comprises a fourth portion electrically connected in series with the second portion of the winding; the second conductive end loops (502, 606, 706) further comprise a second outer end loop (606, 706); the second outer end loop (606, 706) electrically interconnects a portion of one of the first pair of second radial conductors (404) at the second radial distance (R2) and a portion of the other of the second radial conductors (404) at the second radial distance (R2); and the fourth portion of the winding comprises the second outer end turn (606, 706). 21. Flat composite structure (PCS) according to any one of claims 18 to 20, characterized in that the first inner end turn, the second inner end turn, and the first outer end turn (606, 706 ) are arranged so that the first, second, and third portions of the first winding form a serpentine pattern. 22. Flat composite structure (PCS) according to any one of claims 17 to 21, characterized in that the first conductive traces and the second conductive traces are arranged so that the first and second portions of the winding form a pattern in serpentine. 23. Flat composite structure (PCS) according to any one of claims 17 to 22, characterized by the fact that: the first radial conductors comprise at least first, second, third, fourth, fifth and sixth radial conductors, the second conductor radial being angularly positioned between the first and third radial conductors and the third radial conductor being angularly positioned between the second and fourth radial conductors; the second radial conductors (404) comprise at least seventh, eighth, ninth and tenth radial conductors; the tracks (310) comprise a first track (310) interconnecting the first and seventh radial conductors, a second track (310) interconnecting the second and eighth radial conductors, a third track (310) interconnecting the third and ninth radial conductors and a fourth track (310) interconnecting the fourth and tenth radial conductors; the first inner end loop interconnects portions of the fifth and sixth radial conductors at the first radial distance (R1); and the second inner end loop interconnects portions of the seventh and ninth radial connectors at the first radial distance (R1); and the first conductive end loops (502, 606, 706) further comprise a third inner end loop (502) that interconnects portions of the second and fourth radial conductors (404) at the first radial distance (R1). 24. Flat composite structure (PCS) for use in an axial flux motor or generator, comprising: a first dielectric layer (DL), a first conductive layer located on a first side of the first dielectric layer (DL), the first layer conductive comprising first conductive traces forming a first portion of a first winding that, when energized, generates magnetic flux to a first phase of the motor or generator, wherein the first conductive traces include: first radial conductors (404), each of the first radial conductors (404) extending radially from at least a first radial distance (R1) to a second radial distance (R2) that is greater than the first radial distance (R1); and first conductive end turns (502, 606, 706), each of the first conductive end turns (502, 606, 706) interconnecting a respective pair of first radial conductors (404), characterized by the fact that: the first layer dielectric (DL) and the first conductive layer (CL) are included in a first subassembly (S) located on a first side of a second dielectric layer (DL), the first subassembly (S) further including: a second conductive layer (CL ) located on a second side of the first dielectric layer (DL), the second conductive layer (CL) comprising second conductive traces that include second radial conductors (404), each of the second radial conductors (404) extending radially at least between the first radial distance (R1) and second radial distance (R2); and first pathways (310) through the first dielectric layer (DL), each of the first radial conductors being electrically connected through at least one respective first via (310) to a corresponding one of the second radial conductors; and a second subset (S) located on a second side of the second dielectric layer (DL), the second subset (S) including: a third dielectric layer (DL), a third conductive layer located on a first side of the third dielectric layer (DL ), the third conductive layer comprising third conductive traces forming a second portion of the first winding, wherein the third conductive traces include: third radial conductors, each of the third radial conductors extending radially at least between the first radial distance (R1) the second radial distance (R2), and second conductive end turns (502, 606, 706), each of the second conductive end turns (502, 606, 706) interconnecting a respective pair of the third radial conductors, and a fourth layer conductive layer located on a second side of the third dielectric layer (DL), the fourth conductive layer comprising fourth conductive traces that include the fourth radial conductors, each of the fourth radial conductors extending radially at least between the first radial distance (R1) and the second radial distance (R2); and second ways (310) through the third dielectric layer (DL), each of the third radial conductors being electrically connected through at least one respective second way (310) to a corresponding one of the fourth radial conductors; wherein: the first portion of the first winding is connected in series with the second portion of the first winding, the first and second portions of the first winding are configured and arranged so that an equal amount of current flows through each of the first and second portions of the first winding, the first subset (S) further includes a third portion of the first winding, the third portion of the first winding includes the first portion of the first winding, the third portion of the first winding circumscribes a first region of the first subset at least once, the second subset (S) further includes a fourth portion of the first winding, the fourth portion of the first winding includes the second portion of the first winding, and the fourth portion of the first winding circumscribes a second region of the second subset (S) by least once. 25. Flat composite structure (PCS) for use in an axial flux motor or generator, comprising: a first dielectric layer (DL); a first conductive layer (CL) on a first side of the first dielectric layer (DL), the first conductive layer (CL) comprising first conductive traces, the first conductive traces including: first radial conductors (404) extending radially from a first radial distance (R1) to a second radial distance (R2) that is greater than the first radial distance (R1), and first conductive end turns (502, 606, 706), each of the first conductive end turns (502, 606, 706) interconnecting a respective pair of first radial conductors; characterized by the fact that it further comprises: a second conductive layer (CL) on a second side of the first dielectric layer (DL), the second conductive layer (CL) comprising second conductive traces, the second conductive traces including: second radial conductors (404 ) extending radially from the first radial distance (R1) to the second radial distance (R2), and second conductive end turns (502, 606, 706), each of the second conductive end turns (502, 606, 706) interconnecting a respective pair of second radial conductors (404); first blind or buried leads (310) through the first dielectric layer (DL), each of the first radial conductors being electrically connected through at least one respective first blind or buried lead (310) to a corresponding second radial conductors (404) ; a second dielectric layer (DL); a third conductive layer (CL) on a first side of the second dielectric layer (DL), the third conductive layer (CL) comprising third conductive traces, the third conductive traces including: third radial conductors (404) extending radially from the first radial distance (R1) to the second radial distance (R2), and third conductive end turns, each of the third conductive end turns interconnecting a respective pair of the third radial conductors; a fourth conductive layer (CL) on a second side of the second dielectric layer (DL), the fourth conductive layer (CL) comprising fourth conductive traces, the fourth conductive traces including: fourth radial conductors (404) extending radially from the first radial distance (R1) to the second radial distance (R2), and fourth conductive end turns, each of the fourth conductive end turns interconnecting a respective pair of the fourth radial conductors; blind or buried second tracks (310) through the second dielectric layer (DL), each of the third radial conductors being electrically connected through at least one respective blind or buried second track to a corresponding fourth radial conductor; and a third dielectric layer (DL) between the second conductive layer (CL) and the third conductive layer (CL). 26. Flat composite structure (PCS) according to claim 25, characterized by the fact that: the first radial conductors (404), the second radial conductors (404), the first conductive end turns (502, 606, 706 ) and second conductive end turns (502, 606, 706) establish electrical paths for a first portion of a winding that, when energized, generates magnetic flux for a first phase of the motor or generator; the third radial conductors (404), the fourth radial conductors (404), the third conductive end loops (502, 606, 702) and the fourth conductive end loops (502, 606, 702) establish electrical paths for a second portion of the winding; and the first portion of the winding is connected in series with the second portion of the winding. 27. Planar composite structure (PCS), according to claim 24, characterized by the fact that: the first subassembly (S) comprises a first plurality of radial conductors (404) extending radially from the first radial distance (R1 ) for the second radial distance (R2), first end turn conductors and second end turn conductors, wherein: the first end turn conductors interconnect a first group of the first plurality of radial conductors to form the first winding for a first stage of the axial flux motor or generator, the second end loop conductors interconnect a second group of the first plurality of radial conductors (404) to form a second winding for a second stage of the axial flux motor or generator, and the first subassembly (S) includes more second end loop conductors than first end loop conductors. 28. Flat composite structure (PCS), according to claim 27, characterized by the fact that: the second subassembly (S) comprises a second plurality of radial conductors (404) extending radially from the first radial distance (R1) to the second radial distance (R2), third end turn conductors, and fourth end turn conductors, wherein: the third end turn conductors interconnect a first group of the second plurality of radial conductors (404) to form a third winding for the first stage of the axial flux motor or generator, the fourth end turn conductors interconnect a second group of the second plurality of radial conductors (404) to form a fourth winding for the second stage of the axial flux motor or generator, and the second subset (S) includes more third end turn conductors than fourth end turn conductors. 29. Flat composite structure (PCS), according to claim 28, characterized by the fact that: the third winding is connected in series with the first winding; and the fourth winding is connected in series with the second winding. 30. Flat composite structure (PCS) according to claim 28 or 29, characterized by the fact that: a number of the first end turn conductors plus a number of the third end turn conductors equals a number of the second end turn conductors plus a number of fourth end turn conductors. 31. Flat composite structure (PCS) according to any one of claims 27 to 30, characterized by the fact that: the first end turn conductors comprise first inner end turn conductors (502) and first end turn conductors (502) outer end (606, 706); the second end loop conductors comprise second inner end loop conductors (502) and second outer end loop conductors (606, 706); each of the first inner end loop conductors (502) electrically interconnects portions of a respective pair of first plurality of radial conductors (404) at the first radial distance (R1); each of the first outer end loop conductors (606, 706) electrically interconnects portions of a respective pair of the first plurality of radial conductors (404) at the second radial distance (R2); each of the second inner end loop conductors electrically interconnects portions of a respective pair of the first plurality of radial conductors (404) at the first radial distance (R1); each of the second outer end loop conductors electrically interconnects portions of a respective pair in the first plurality of radial conductors (404) in the second radial distance (R2); the first subassembly (S) includes the same number of first inner end loop conductors (502) as the second inner end loop conductors (502); and the first subassembly (S) includes more second outer end loop conductors (606, 706) than first outer end loop conductors (606, 706).