GB2559441A

GB2559441A - Electrical motor arrangement for electrical vehicles

Info

Publication number: GB2559441A
Application number: GB1714896.6A
Authority: GB
Inventors: lam Albert
Original assignee: DE Innovation Lab Ltd
Current assignee: DE Innovation Lab Ltd
Priority date: 2017-09-15
Filing date: 2017-09-15
Publication date: 2018-08-08
Also published as: WO2019053669A2; GB201714896D0; WO2019053669A3

Abstract

An electric motor for an electrical vehicle comprises a stator 104 mounted on a casing 102; and a rotor 108 whose shaft 110 is disposed within a hole 106 in stator elements 104A,B and is supported relative to the stator by bearings 120A,B that can be coupled to the shaft ends.There are winding coils 116 on planar rotor elements 108 and winding coils 114 on planar stator elements 104. Plate-like rotor elements 108 mutually abut the plate-like stator elements 104 with a planar magnetic gap between them. Bearings 120 can comprise magnetic bearings or a combination of magnetic and mechanical bearings that bear the rotor under load causing mechanical contact of the magnetic bearing gap. The motor can be digitally commutated using pulse width modulation and a free-wheeling period between current pulses. Power to the rotor to establish a rotor magnetic field can be supplied by resonant inductive coupling via a rectifier (fig 4, 412). The coil windings may be printed circuit board tracks and the rotor may be reinforced using a carbon fibre ring. This electric motor can alternatively be implemented with a central stator encircled by an external rotor.

Description

(71) Applicant(s):

DE Innovation Lab Limited Detroit Electric, Spa Park, 5-6 Harrison Way, Leamington Spa, Warwickshire, CV31 3HJ, United Kingdom (72) Inventor(s):

Albert Lam

(51) INT CL:
H02K 19/10 (2006.01) H02K 5/16 (2006.01) H02K 29/00 (2006.01)	H02K1/18 (2006.01) H02K11/04 (2016.01)
(56) Documents Cited: CN 104734413 A JP 2016178830 A JP H09121479	CN 002529437 Y US 5057726 A
(58) Field of Search: INT CL H02K Other: EPODOC, WPI

(74) Agent and/or Address for Service:

Basck Ltd

Saxon Road, CAMBRIDGE, Cambridgeshire, CB5 8HS, United Kingdom (54) Title of the Invention: Electrical motor arrangement for electrical vehicles

Abstract Title: Axial gap motor for an electric vehicle having a wound rotor and a wound stator (57) An electric motor for an electrical vehicle comprises a stator 104 mounted on a casing 102; and a rotor 108 whose shaft 110 is disposed within a hole 106 in stator elements 104A,B and is supported relative to the stator by bearings 120A.B that can be coupled to the shaft ends.There are winding coils 116 on planar rotor elements 108 and winding coils 114 on planar stator elements 104. Plate-like rotor elements 108 mutually abut the plate-like stator elements 104 with a planar magnetic gap between them. Bearings 120 can comprise magnetic bearings or a combination of magnetic and mechanical bearings that bear the rotor under load causing mechanical contact of the magnetic bearing gap. The motor can be digitally commutated using pulse width modulation and a free-wheeling period between current pulses. Power to the rotor to establish a rotor magnetic field can be supplied by resonant inductive coupling via a rectifier (fig 4, 412). The coil windings may be printed circuit board tracks and the rotor may be reinforced using a carbon fibre ring. This electric motor can alternatively be implemented with a central stator encircled by an external rotor.

100

122 A

FIG. 1

1/3

122A

FIG. 1

2/3

FIG. 2

FIG. 3

400

FIG. 4

- 1 ELECTRICAL MOTOR ARRANGEMENT FOR ELECTRICAL VEHICLES

TECHNICAL FIELD

The present disclosure relates generally to electrical motor arrangements; more specifically, the present disclosure relates to electrical motor arrangements for electrical vehicles.

BACKGROUND

Recently, vehicles have become an integral part of everyday life. Such vehicles, and specifically automobiles, have introduced convenience and comfort when addressing daily transportation needs. Contemporarily, automobiles are capable of traversing distances of several hundred miles or kilometres within relatively short periods of time, for example within hours. With advancements in automobile technology, there has recently been an increase in interest for electrical vehicles, for example to address pollution issues in large cities and to try to move humanity towards a more sustainable future in terms of utilization of Earth's resources.

Presently, there are consumed 80 million barrels of oil per day to keep industrial civilization functioning; a significant portion of such consumption is utilized for transporting goods and people.

Thus, electrical vehicles are potentially capable of playing a significant role in reducing environmental pollution and encouraging sustainable technologies. Typically, the electrical vehicles produce fewer byproducts that cause anthropogenic climate change in comparison to conventional vehicles powered by fossil fuels; the electrical vehicles

-2are susceptible to being provided with power from renewable energy sources such as solar panels, wind turbines, tidal power generation arrangements, ocean wave power, geothermal energy and so forth. However, it has been appreciated that electrical vehicles of superlative performance have to be manufactured to encourage people to use electrical vehicles instead of correspondingperformance internal combustion engine vehicles.

Generally, contemporary electrical vehicles include high performance vehicles which utilize large motor arrangements and provide brisk accelerations when in operation. Usually, such motor arrangements are known to include one or more electrical motors. Such an electric motor incudes a stator and/or rotor that employ permanent magnets. Such use of permanent magnets leads to a large and heavy design of the motor. Furthermore, in order to provide high performance (such as high torque using the motor arrangement), the permanent magnets may include powerful rare-earth magnets. It will be appreciated that using such rare earth magnets leads to high manufacturing costs associated with the motor arrangements and consequently, high manufacturing costs associated with corresponding electrical vehicles including such motor arrangements. Furthermore, in operation of the aforesaid electrical motor, one or more moving components thereof (for example, a rotor thereof) may be subjected to physical contact between one or more stationary components of the aforesaid electrical motor (for example, a stator thereof). It will be appreciated that during a high rate of rotation of the aforesaid electrical motor and/or long periods of operation of aforesaid electrical motor, such physical contact may increase wear and tear within the aforesaid electrical motor, thereby leading to a shorter operating life thereof. Additionally, to reduce a size of the

-3electrical motor, a magnetic clearance gap that is included between various components of the electric motor is reduced. In high speed operation of the electrical vehicle, heat is generated in the electrical motor, for example due to resistance (or drag) between the one or more moving components of the electrical motor and air within the electrical motor, and/or resistive electrical power dissipation within the electrical motor. Dissipating such heat generated within the electrical motor can potentially represent a severe technical problem, for example when the electrical motor is implemented in a compact format.

Therefore, in light of the foregoing discussion, there is a need to overcome the aforementioned drawbacks associated with conventional motor arrangements employed in electrical vehicles.

High-performance compact digital motors are known for use in portable electrical appliances, for example portable vacuum cleaners and hair driers. Such compact digital motors are described, for example, in a published patent document W02010/112930 A2 {High-speed electric system, applicant - Dyson Technology Ltd.,

UK). These high-performance compact digital motors employ rareearth permanent magnets.

SUMMARY

The present disclosure seeks to provide an improved electrical motor arrangement for an electrical vehicle, wherein the electrical motor arrangement includes at least one electrical motor.

According to a first aspect, an embodiment of the present disclosure provides an electrical motor arrangement for an electrical vehicle, the

-4electrical motor arrangement including at least one electrical motor, characterized in that the at least one electrical motor includes:

- a casing;

- a stator mounted on the casing, the stator including one or more 5 planar stator elements extending from the casing, wherein each of the one or more planar stator elements includes a central hole therein; and

- a rotor including

- a rotor shaft that is disposed within the central hole of each 10 of the one or more planar stator elements of the stator; and

- one or more planar rotor elements attached to the rotor shaft;

wherein principal planes of the one or more planar stator and rotor elements are arranged mutually to abut with a magnetic separation gap therebetween, and the one or more planar stator elements and the one or more planar rotor elements are arranged to have electrical winding coil arrangements disposed thereon; and

- a bearing arrangement that rotationally supports the rotor relative to the stator.

Optionally, the bearing arrangement includes a magnetic bearing 20 arrangement for providing non-contact rotation of the rotor relative to the stator.

Optionally, the one or more planar elements of the rotor and the stator are implemented as radial plate-like elements having a circular periphery.

- 5 The present disclosure seeks to provide an efficient electrical motor arrangement for an electrical vehicle; moreover, the electrical motor arrangement is capable of being fabricated inexpensively, in a lightweight and compact format, wherein the electrical motor arrangement is capable of improving performance of an electrical vehicle when utilized therein.

It will be appreciated that features of the present disclosure are susceptible to being combined in various combinations without departing from the scope of the present disclosure as defined by the appended claims.

The present invention is included in the general business context, which aims to substitute vehicles powered by traditional fuels, for example gasoline or diesel, by electric vehicles. In particular, the present invention is intended for use in electric vehicles used within cities, which can be highly beneficial to the local environment due to significant reduction of gaseous emissions as well as significant reduction of noise. Overall environmental benefits can also be significant when electric vehicles are charged from renewable energy sources.

DESCRIPTION OFTHE DRAWINGS

The summary above, as well as the following detailed description of illustrative embodiments, is better understood when read in conjunction with the appended drawings. For the purpose of illustrating the present disclosure, exemplary constructions of the disclosure are shown in the drawings. However, the present disclosure is not limited to specific methods and instrumentalities

-6disclosed herein. Moreover, those in the art will understand that the drawings are not to scale. Wherever possible, like elements have been indicated by identical numbers.

Embodiments of the present disclosure will now be described, by way of example only, with reference to the following diagrams wherein:

FIG. 1 is a schematic illustration of an electrical motor arrangement for an electrical vehicle, wherein the electrical motor arrangement includes at least one electrical motor, in accordance with an embodiment of the present disclosure;

FIG. 2 is a top-view of a planar stator element, for example implemented as a radial plate-like element having a circular periphery, within a casing of the at least one electrical motor FIG. 1, in accordance with an embodiment of the present disclosure;

FIG. 3 is a top-view of the planar rotor element of FIG. 1, for example implemented as a plate-like element having a circular periphery, in accordance with an embodiment of the present disclosure; and

FIG. 4 is a circuit configuration of electrical circuit implemented for operation of the at least one electrical motor (such as the at least one electrical motor of FIG. 1), in accordance with an embodiment of the present disclosure.

In the accompanying drawings, an underlined number is employed to represent an item over which the underlined number is positioned or an item to which the underlined number is adjacent. A non-underlined number relates to an item identified by a line linking the nonunderlined number to the item. When a number is non-underlined

-1 and accompanied by an associated arrow, the non-underlined number is used to identify a general item at which the arrow is pointing.

DESCRIPTION OF EMBODIMENTS

In overview, embodiments of the present disclosure are concerned with improved electrical motor arrangements for electrical vehicles.

Referring to FIG. 1, there is shown a schematic illustration of an electrical motor 100, for example for including in a motor arrangement of an electrical vehicle, in accordance with an embodiment of the present disclosure. The electrical motor 100 includes a casing 102. The casing 102 is operable, namely configured, to accommodate one or more components (as described herein later) of the electrical motor 100 therein. In one example, the casing 102 is implemented as a hollow cylindrical structure that is operable to accommodate the one or more components of the electrical motor 100. In another example, the casing 102 is implemented as a hollow cylindrical structure including a plurality of parts, for example two semi-cylindrical parts, alternatively for example four quadrant parts. In such an instance, the semicylindrical parts are operable, namely configured, to abut, when assembled, along surfaces thereof, to form the casing 102. It will be appreciated that such an implementation of the casing 102 including the plurality of parts enables convenient assembly (and/or disassembly) of the electrical motor 100.

For example, the one or more components of the electrical motor 100 are assembled together and, subsequently, enclosed within the casing 102 thereon. In an example, the casing 102 is fabricated from a metallic material, for example from one or more profiled and pressed metal sheets, from one or more castings or from one or more

-8machined component. The metallic material employed for the casing 102 includes, for example, at least one of: Aluminium, Titanium, steel, Copper, metal alloy. In an example, there is used Aluminum sheet for fabricating the casing 102. Such fabrication of the casing

102 using the Aluminium sheet allows a lightweight casing structure to be fabricated with a low associated manufacturing cost. Additionally, using the Aluminum sheet for fabricating the casing 102 enables convenient dissipation of heat generated during operation of the electrical motor 100. In another example, the casing 102 is io fabricated using a steel sheet, for example as aforementioned. Optionally, the casing 102 includes an exterior cavity through which a cooling fluid, for example force air cooling, can be flowed when the one electrical motor 100 is in operation.

Furthermore, the electrical motor 100 includes a stator 104 mounted onto an interior of the casing 102. The stator 104 is a stationary component of the electrical motor 100. Furthermore, the stator 104 is operable to provide a magnetic field to enable operation of one or more rotatable components (such as a rotor) of the electrical motor 100. The stator 104 includes one or more planar stator elements

104A-B, for example the one or more stator elements 104A-B are implemented as one or more plate-like radial elements each having a circular periphery and a central hole therein, extending from the casing 102, wherein each of the one or more planar stator elements 104A-B includes a central hole 106. Optionally, principal planes of the one or more planar stator elements 104A-B are arranged to be substantially orthogonal to a central axis of rotation of a rotor of the electrical motor 100. By substantially orthogonal is meant in a range of +45° to +135°, more optionally in a range of 70° to 110°, and yet more optionally in a range of 80° to 100°.

-9In one example, the one or more planar stator elements 104A-B are fabricated to include a highly paramagnetic material, for example a ferromagnetic material, for example, a ferrite material or a ferromagnetic laminate structure, are optionally reinforced using at least one of: fiberglass (fibreglass), Carbon fiber (Carbon fibre), an electrically insulating material including an organic binding resin. Beneficially, although the one or more planar stator elements 1O4AB are fabricated a highly paramagnetic material, the one or more planar stator elements 104A-B exhibit a low electrical conductivity in order to reduce eddy currents generation therein when subjected to a temporally changing magnetic field in operation. Furthermore, the one or more planar stator elements 104A-B, for example implemented radial plate-like elements having a circular periphery, are attached to an inside of the casing 102, as aforementioned. In one example, the one or more planar stator elements 104A-B are implemented in a plurality of parts, for example as semi-circular half plates that are operable to be arranged to form the one or more planar stator elements 104A-B. For example, the casing 102 is implemented as a semi-cylindrical structure. In such an instance, the one or more planar stator elements 104A-B including semi-circular half plates are formed as an integral part of the plurality of semicylindrical structures of the casing 102. Such an implementation of the one or more planar stator elements 104A-B enables easy assembly and disassembly of one or more components of the electrical motor 100. Additionally, the one or more planar stator elements 104A-B includes a central hole 106 that enables one or more components (such as a rotor shaft) of the electrical motor 100 to be accommodated therein when the electrical motor 100 is in an assembled state.

- 10Moreover, the electrical motor 100 includes a rotor 108. The rotor 108 is a rotatable component of the electrical motor 100. The rotor 108 is rotatably mounted relative to the stator 104, and is operable in cooperation with the stator 104 to provide rotational mechanical power for rotating one or more wheels of the electrical vehicle. In an embodiment, the rotor 108 is operable to rotate at a maximum rotation rate in a range of 30000 rotations per minute (r.p.m.) to 100000 rotations per minute (r.p.m.). It will be appreciated that such a high rotation rate of the rotor 108 enables the electrical motor 100 to be constructed in a relatively light-weight and compact format, and yet able to output considerable rotation mechanical power; for example, the electrical motor 100 is susceptible to being manufactured to provide a rotational mechanical output power of 100 kW and weigh in a range of 3 kg to 10 kg, to have the casing 102 having a diameter in a range of 20 cm to 40 cm, and to have the casing 102 having a length in a range of 25 cm to 50 cm. The rotor 108 includes a rotor shaft 110 that is disposed in operation within the central hole 106 of each of the one or more planar stator elements 104A-B of the stator 104. For example, the rotor shaft

110 is implemented as a cylindrical structure, for example with a solid cross-section or a hollow cross-section (to reduce weight), that is operable to rotate around an elongate axis of the rotor shaft 110. Furthermore, the rotor 108 includes one or more planar rotor elements 108A-B attached to the rotor shaft 110; optionally, the one or more planar rotor element 108A-B are implemented as one or more radial plate-like elements having a circular periphery. In one example, the one or more planar rotor elements 108A-B are fabricated to include a highly paramagnetic material, for example a ferrite material or a laminate ferromagnetic material (for example, laminate Silicon steel sheet). Beneficially, the one or more planar

-11 rotor elements 108A-B are reinforced using fiberglass (fibreglass), Carbon fiber (Carbon fibre) or similar. The one or more planar rotor elements 108A-B are fabricated from a material that exhibits a low electrical conductivity in order reduce eddy correct effects when the one or more planar rotor elements 108A-B are subjected to temporally changing magnetic fields when in operation. Furthermore, the one or more planar rotor elements 108A-B are attached to the rotor shaft 110 along an elongate axis thereof. The one or more planar rotor elements 108A-B are arranged so that their principal planes are substantially orthogonal to the rotor shaft 110; by substantially orthogonal is meant in a range of +45° to +135°, more optionally in a range of 70° to 110°, and yet more optionally in a range of 80° to 100°. Optionally, the one or more planar rotor elements 108A-B are tapered as a function of radial distance from the elongate axis of the rotor shaft 110, wherein the one or more planar rotor elements 108A-B are thicker where they are adjoined to the rotor shaft 110 and thinner at their distal circumferential edge remote from the rotor shaft 110. There is beneficially employ for the one or more planar rotor elements 108A-B a tapering angle in a range of 0.5° to 5° for an exposed principal planar surface of the one or more planar rotor elements 108A-B and an orthogonal radial direction from the elongate axis of the rotor shaft 110; the one or more planar stator elements 104A-B are then correspondingly inversely tapered such that they are thicker where they adjoin to the casing 102 and thinner at their distal edge remote from the casing 102, such that a uniform gap is provided between external surface of the one or more stator elements 104A-B and their corresponding one of more planar rotor elements 108A-B.

- 12Furthermore, in operation, heat may be generated in the electrical motor 100, for example due to resistance (or drag) of the rotating rotor 108 against air within the electrical motor 100, flow of electrical current through one or more components of the electrical motor 100, and so forth. In such an instance, providing one or more planar stator elements 104A-B, for example one or more radial plate-like elements as aforementioned, and the one or more planar rotor elements 108A-B, for example one or more radial plate-like elements as aforementioned, enables improved air flow (such as, between the one or more planar stator and rotor elements) within the electrical motor 100 for heat transfer purposes, namely cooling purposes. Consequently, the improved air flow within the electrical motor 100 makes it practical for the electrical motor 100 to be air cooled, thereby, reducing a requirement of external cooling arrangements to be accommodated therein. It will be appreciated that such air cooling of the electrical motor 100 can be arranged in a lightweight and compact design and furthermore, will be associated with a lower manufacturing cost (due to reduced costs associated with cooling arrangements). Additionally, such air cooling enables a high speed operation of the electrical motor 100 to be achieved, to achieve a high mechanical output power from the electrical motor 100 relative to its physical size.

Moreover, principal planes of the one or more planar stator elements 104A-B and rotor elements 108A-B are arranged mutually to abut with a magnetic separation gap 112 therebetween, as aforementioned, to allow the rotor 108 to rotate relative to the stator 104. For example, the one or more planar rotor elements 108A-B, for example one or more radial plate-like elements as aforementioned, are attached to the rotor shaft 110 such that the

- 13one or more planar rotor elements 108A-B are positioned alternately with the one or more planar stator elements 104A-B of the stator 104, for example as illustrated in FIG. 1. In such an instance, it will be appreciated that the one or more planar stator elements 104A-B do not obstruct the rotation of the rotor 108 as the one or more planar rotor elements 108A-B of the rotor 108 are disposed in a gap formed by two adjacent planar stator elements 104A-B. Furthermore, such an arrangement of the one or more planar stator elements 104A-B and the one or more planar rotor elements 108A10 B enables formation of the aforementioned magnetic separation gap 112 therebetween. For example, the magnetic separation gap 112 is defined by a distance between surface principal planes of the one or more radial planar stator elements 104A-B and surface principal planes of the one or more planar rotor elements 108A-B (such as, for example, surface planes of the one or more planar stator elements 104A-B and surface planes of the one or more planar stator elements 108A-B facing each other, for example as illustrated in FIG. 1). According to an embodiment, the magnetic separation gap 112 is in a range of 0.1 mm to 10.0 mm, more optionally in a range of 0.3 mm to 5.0 mm and yet more optionally substantially 0.9 mm; substantially here pertains to an order of +/- 25% variation. In one example, the magnetic separation gap 112 is substantially 1.0 mm. In another example, the magnetic separation gap is substantially 4.5 mm.

Moreover, the one or more planar stator elements 104A-B and the one or more planar rotor elements 108A-B are arranged to have electrical winding coil arrangements disposed thereon. In one example, the one or more planar stator elements 104A-B are arranged to have electrical winding coil arrangements 114A-B

- 14disposed thereon. Such electrical winding coil arrangements 114AB enable there to be provided a stator magnetic field that interacts with a rotor magnetic field generated by the rotor 108 to enable a torque to be generated by the electrical motor 100. In an embodiment, the electrical winding coil arrangements 114A-B are implemented using printed circuit board conductive tracks; for example, a printed circuit board is utilized having conductive tracks that are electro-plated to increase their thickness after lithography to enable them to handle more current, for example currents approaching, at least momentarily, 100 Amperes. Optionally, the printed circuit board conductive tracks are implemented in a multilayer circuit board arrangement to allow more windings to be accommodated in a very limited volume of the one or more planar stator elements 108A-B. A similar manner of providing windings pertains also to the rotor 108; in operation, the rotor 108 is provided with a magnetizing current by using wireless resonant inductive power coupling from the stator 104, wherein the rotor 108 includes thereon a rectifying arrangement, for example implemented using Silicon PN diodes, Silicon Carbide diodes or Schottky junction diodes, for rectifying inductively coupled power received at the rotor 108 into DC (direct current) magnetizing current for windings of the rotor 108, disposed on the one or more planar rotor elements 108A-B of the rotor 108. Examples of such an implementation will be described in greater detail later.

For example, the one or more planar stator elements 104A-B are implemented as printed circuit boards that are fabricated using fiberglass (fibreglass). In such an instance, the electrical winding coil arrangements 114A-B are implemented as copper conductive tracks that are lithographically (for example, using optical lithography)

- 15printed on the printed circuit boards; alternatively, a lithographicallydefined etching process is employed to define the winding coil arrangements 114A-B. Furthermore, such conductive tracks associated with the one or more planar stator elements 104A-B enable a flow of electrical current therethrough. Such a flow of electrical current through the conductive tracks enables the stator 104 to function as an electromagnet for providing the magnetic field for generating a torque to rotate the rotor 108.

In an embodiment, the electrical motor 100 includes non-permanent10 magnet ferrite elements for defining a torque-generating magnetic field for the electrical motor 100 when in operation, as aforementioned. In one example, the non-permanent-magnet ferrite elements are implemented as unmagnetized ferrite cores within the one or more planar stator elements 104A-B. In one example, each of the one or more planar stator elements 104A-B are implemented as a plurality of layers that are arranged to form the one or more planar stator elements 104A-B; for example, layers of ferrite ceramic or Silicon steel transformer plates are interposed alternately between fiberglass support layers, wherein the fiberglass support layers are insulating to reduce eddy current losses and provide for a robust mechanical structure to be achieved. In such an instance, the unmagnetized ferrite cores are implemented as a ferromagnetic ferrite planar element that is incorporated (or sandwiched) between layers comprising each of the one or more planar stator elements

104A-B. In one example, the ferromagnetic planar element is fabricated using Silicon steel, for example sheets of silicon steel as conventionally employed in laminated transformer cores. In another example, the planar element has a thickness in a range of 100 micrometers (pm) to 3000 micrometers (pm), more optionally in a

- 16range of 250 micrometers (pm) to 2000 micrometers (pm). In such an instance, the unmagnetized cores enable there to be provided a low magnetic reluctance path for the magnetic field associated with the stator 104. Furthermore, it will be appreciated that the magnetic field is provided substantially orthogonally to the principal planes of the one or more planar stator and rotor elements. According to an embodiment, the unmagnetized cores, for example ferrite cores, have a relative permeability (μ_Γ) in a range of 10 to 3000 and more optionally, in a range of 100 to 1000. In one example, the unmagnetized cores are fabricated from iron alloy powder, by using a technique such as powder sintering. In such an instance, an electrical conductivity associated with the unmagnetized ferrite cores is low as compared to the relative permeability thereof, to reduce magnetic hysteresis associated with the provided magnetic field and/or to reduce induced eddy currents associated with electrical power provided to the electrical winding coil arrangements 114A-B.

In an example, the one or more planar rotor elements 108A-B are arranged to have electrical winding coil arrangements 116A-B disposed thereon. According to an embodiment, the electrical winding coil arrangements 116A-B are implemented using printed circuit board conductive tracks, for example as described in the foregoing. For example, the one or more planar rotor elements 108A-B are implemented as printed circuit boards that are fabricated using fiberglass (fibreglass) substrates. In such an instance, the electrical winding coil arrangements 116A-B are implemented as conductive tracks that are lithographically printed on the printed circuit board; alternatively, the conductive tracks are produced using a lithographically-defined etching process. In one example, the printed circuit board includes copper conductive tracks.

- 17In an example embodiment, the electrical motor 100 includes a mechanical bearing arrangement for rotationally supporting the rotor shaft 110 relative to the stator 104 and the casing 102. Alternatively, the electrical motor 100 includes a magnetic bearing arrangement, for example implement by magnetic bearings 118A-B coupled to ends of the rotor shaft 110, for rotationally supporting the rotor shaft 110 relative to the stator 104. Yet alternatively, the electrical motor 100 optionally includes a combination of the magnetic bearing arrangement and the mechanical bearing arrangement for rotationally supporting the rotor shaft 110 relative to the stator 104. Optionally, the mechanical bearing arrangement provides support only when the electrical motor 100 is delivering considerable mechanical power, for example in excess of 10 kW mechanical power, otherwise the magnetic bearing arrangement provides support.

For example, the rotor 108 is beneficially operable to rotate up to high rotation rates, such as up to rotation rates in a range of 30000 rotations per minute (r.p.m.) to 100000 rotations per minute (r.p.m.). In such an instance, the magnetic bearing arrangement is operable to prevent physical contact between the rotor shaft 110 and one or more other components of the electrical motor 100, such as, for example, the one or more planar stator elements 104A-B. The magnetic bearing arrangement is operable to restrain the rotor shaft 110 relative to an axial direction parallel to an elongate axis of the rotor shaft 110, but to allow for the rotor shaft 110 to rotate freely relative to the stator 104. The magnetic bearing arrangement is beneficially implemented using permanent magnets, for example using rare-earth permanent magnets, or is implemented using electromagnets, or using a combination of permanent magnets and

- 18electromagnets. Optionally, the electromagnets are only energized when the electrical motor 100 is under heavy load during operation, for example delivering more than 10 kW mechanical power.

As shown, the magnetic bearings 118A-B include rings that are coupled to the rotor shaft 110 at two ends thereof. Furthermore, the magnetic bearings 118A-B include rings that are coupled to the stator 104 opposite to the rings coupled to the rotor shaft 110. In such an instance, the rings coupled to the rotor shaft 110 and the rings coupled to the stator 104 are associated with same magnetic poles (such as magnetic north poles or magnetic south poles). It will be appreciated that providing such same magnetic poles on the magnetic bearings 118A-B enables to maintain a gap between the rotor 108 and the stator 104 using magnetic levitation (such as, by magnetic repulsion therebetween). In an embodiment, the magnetic bearings 118A-B include one or more permanent magnets, as aforementioned. For example, the magnetic bearings 118A-B includes one or more rare-earth magnets. In one example, the one or more rare-earth magnets are neodymium rare-earth magnets.

According to one embodiment, the rotor 108 of the electrical motor

100 is further provided with mechanical bearings 120A-B that bears the rotor 108 relative to the stator 104 when the magnetic bearings 118A-B are loaded to cause at least a portion of a gap of the magnetic bearings 118A-B to be mechanically contacted. For example, at a high speed operation of the electrical motor 100 due to the high rotation rate of the rotor 108, a load on the rotor shaft 110 increases. Consequently, a load associated with the magnetic bearings 118A-B increases. In such an instance, the gap between the rotor 108 and the stator 104 decreases, leading to a bottoming out condition of the magnetic bearings 118A-B (such as a condition

- 19associated with physical contact of the rings coupled to the rotor shaft 110 and the stator 104 respectively). In such an instance, the mechanical bearings 120A-B enable to reduce friction associated with the physical contact of the rings of the magnetic bearings 118A5 B. In one example, the mechanical bearings 120A-B include a ballrace bearing arrangement. In such an instance, rotation ofthe rotor 108 is supported by rolling of a plurality of balls on races associated with the ball-race bearing arrangement. In another example, the mechanical bearings 120A-B include a roller-race bearing arrangement. In such an instance, rotation of the rotor 108 is supported by rolling of a plurality of rollers on races associated with the roller-race bearing arrangement.

In one embodiment, the electrical motor 100 includes a plurality of ferrite spacer rings 122A-B. For example, the ferrite spacer rings

122A-B are arranged between the one or more planar stator elements 104A-B. In such an instance, the plurality of ferrite spacer rings 122A-B further enables to provide the magnetic field substantially orthogonally to the principal planes of the one or more planar stator elements 104A-B and the one or more planar rotor elements 108A-B.

Referring to FIG. 2, there is shown a top-view of the planar stator element 104A within the casing 102 of FIG. 1, in accordance with an embodiment of the present disclosure. As shown, the planar stator element 104A is optionally implemented as semi-circular half plates

202A-B. Furthermore, each half-plate includes electrical winding coil arrangements 114A-B implemented as phase coils Pl, P2 and P3. As shown, the phase coils Pl, P2 and P3 are disposed in a 3-phase arrangement and at a sector angle of 180°, namely 60° per phase P, such that each semi-circular half plates 202A-B includes the phase

-20coils Pl, P2 and P3 associated with the 3-phases. In one example, the phase coils Pl, P2 and P3 are disposed at a sector angle of 90°, namely 30° per phase P. In another example, each of the phase coils Pl, P2 and P3 are formed at an angle of 60°. In yet another example, each of the phase coils Pl, P2 and P3 is associated with multiple turns of conductive tracks thereon. Moreover, the planar stator element 1O4A includes the central hole 106 for accommodating the rotor shaft 110 therein.

Referring to FIG. 3, there is shown a top-view of the planar rotor element 108A of FIG. 1, in accordance with an embodiment of the present disclosure. As shown, the planar rotor element 108A is attached to the rotor shaft 110; the planar rotor element 108A is implemented as a radial plate-like element having a circular distal peripheral edge. Furthermore, the planar rotor element 108A includes electrical winding coil arrangements 116A-B implemented as winding coils C. As shown, the winding coils C are formed at an angle of 60° and moreover, the winding coils C are disposed at a sector angle of 180° on the planar rotor element 108A. In one example, the winding coils C are disposed at a sector angle of 90° on the radial plate-like rotor element 108A. In another example, each of the winding coils C is associated with multiple turns of conductive tracks thereon.

In one embodiment, the one or more planar rotor elements 108A includes a peripheral edge reinforcement arrangement 302 for converting radial forces acting upon the rotor 108 when rotating in operation into corresponding circumferential forces. For example, during high speed operation of the at least one electrical motor 100, the one or more planar rotor elements 108A-B experience large centrifugal forces due to a high rotation rate of the rotor 108, for

-21 example as aforementioned with maximum rotation rates in a range of 30000 r.p.m. to 100000 r.p.m.. It will be appreciated that such large centrifugal forces may lead to damage of the one or more planar rotor elements 108A. In such an instance, the peripheral edge reinforcement arrangement 302 is operable to substantially absorb the centrifugal forces experienced by the one or more planar rotor elements 108A-B, converting such centrifugal forces to peripheral circumferential forces, thereby, preventing damage to the one or more planar rotor elements 108A-B. In an example, the rotor 108 and/or the stator 104 only each include a single planar element thereon; alternatively, the rotor 108 and/or the stator 104 each include a plurality of planar elements thereon. According to an embodiment, the peripheral edge reinforcement arrangement 302 includes a carbon fiber ring. For example, the carbon fiber ring is associated with a same thickness as a thickness of the one or more planar rotor elements 108A-B at their distal peripheral edge. In such an instance, the carbon fiber ring is arranged around the peripheral edge of the one or more planar rotor elements 108A-B. According to another embodiment, the peripheral edge reinforcement arrangement 302 includes a ceramic ring.

Referring to FIG. 4, there is shown a circuit configuration of an electrical circuit 400 implemented for operation of the electrical motor (such as the electrical motor 100 of FIG. 1), in accordance with an embodiment of the present disclosure. As shown, the electrical circuit 400 includes a battery arrangement 402, for example a 400 Volt battery unit having a storage capacity of 200 Ampere-hours. Furthermore, the electrical circuit 400 includes a rotor excitation unit 404 for transferring power using a resonant inductive power coupling arrangement 406. The resonant inductive power coupling arrangement 406 is operable to provide electrical power to the rotor 408 (such as the rotor 108 of FIG. 1) using resonant inductive power coupling. Subsequently, a current return of the rotor excitation unit 404 is directed to a negative terminal of the battery arrangement 402 via a stator 410 (such as the stator 104 of FIG. 1). Such an arrangement is slightly akin to a known series-coupled electrical motor. The resonant inductive power coupling arrangement 406 is operable to function at a resonant frequency in a range of 50 kHz to 1 MHz, more optionally at a resonant frequency in a range of 100 kHz to 300 kHz.

In an embodiment, the battery arrangement 402 includes Lithium Iron Phosphate (LiFePOzQ gel polymer cells.

In an embodiment, the rotor 408 includes a rectifier arrangement 412 for converting resonant inductively coupled power received at the rotor 408 into direct current (DC) to generate the rotor magnetic field. For example, the resonant inductive power coupling arrangement 406 is operable to transfer alternating current (AC) to the rotor 408. Subsequently, the rectifier arrangement 412 is operable to convert the transferred alternating current to direct current. In an example, the rectifier arrangement 412 includes a bridge rectifier arrangement. Furthermore, the rectifier arrangement 412 provides the converted direct current to the electrical winding coil arrangements 414, disposed on one or more planar rotor elements of the rotor 408 (such as the one or more planar rotor elements 108A-B of the rotor 108 of FIG. 1, as described in the foregoing). Consequently, flow of the converted direct current through the electrical winding coil arrangements 414 enables to generate a magnetic field of the rotor 408. The magnetic field of the rotor 408 interacts in operation with a magnetic field of a

-23corresponding stator to generate torque, wherein the magnetic field of the stator is commutated to define a rate of rotation of the rotor 408. Moreover, in operation the magnetic field of the stator is commutated in a digital manner, for example as described in the earlier patent document W02010/112930 A2 (High-speed electric system, applicant - Dyson Technology Ltd., UK), that is hereby incorporated by reference. In such a manner of operation, phases Pl, P2 and P3 of the stator are excited by current pulses, namely in a commutated manner, with non-excited periods therebetween to allow the rotor 408 to freewheel during the non-excited periods. Optionally, the pulses are pulse-width-modulated (PWM) controlled to control a torque generated by the electrical motor 100, and rate of commutation of the phases Pl, P2 and P3 is used to control a rate of rotation of the rotor 408. It will be appreciated that the electrical motor 100 is optionally operated in a slippage manner of operation wherein the rotor 408 lags a rate of commutation o the phases Pl, P2 and P3. However, it will be appreciated that the electrical motor 100 is not limited to three phases, and can optionally be implemented with other numbers of phases, for four-phase, five20 phase and so forth, even potentially two-phase.

In an embodiment, the stator 410 is provided with a silicon carbide transistor switching arrangement 416 for switching commutation magnetizing currents supplied to the stator 410 when in operation: silicon carbide transistors are highly beneficial because devices can be bought commercially at modest cost that can switch 100's of Amperes current within nanoseconds. However, it will be appreciated that other types of switching devices are optionally employed, for example FET's, bipolar transistors, D-MOS FET transistors and so forth. As shown, the stator 410 includes a three-phase arrangement

-24including phase coils Pl, P2, P3 and the switching arrangement 416. Furthermore, the switching arrangement 416 includes switching elements SI, S2, S3. Moreover, a negative connection of the rotor excitation unit 404 is coupled via the phase coils Pl, P2, P3 and their respective switches SI, S2, S3 to the negative terminal of the battery arrangement 402. Additionally, the phase coils Pl, P2, P3 are associated with the electrical winding coil arrangements (such as the electrical winding coil arrangements 114A-B of FIG. 1) disposed on the one or more planar stator elements of the stator 410.

In an embodiment, the electrical motor including the rotor 408 and stator 410 is operable to function as a digitally-commutated electrical motor, for example in a manner as aforementioned. Specifically, digital commutation is provided to generate motion in the electrical motor 100. For example, digital commutation is implemented using digitally controlled current pulses. Optionally, the rotor magnetic field is operable to interact in operation with a commutated magnetic field of a stator 410 of the electrical motor 100. More optionally, during commutation, the current pulses are applied to commutation windings of the electrical motor 100, and a free-wheeling period is implemented between application of the current pulses during which the commutation windings are non-energized. Specifically, commutation windings of the electrical motor 100 include an electrical winding coil arrangement disposed on the one or more planar stator elements of the stator 410. Therefore, current pulses are applied to the phase coils Pl, P2, P3 using the switching arrangement 416, for example in a sequential commutated manner, specifically to the switching elements SI, S2, S3, respectively. In operation, a current pulse is applied to the phase coil Pl of the commutation winding using the switching element SI to generate a

-25motion in the rotor 408. Subsequently, the current pulse is switched to phase coil P2 of commutation winding using the switching element S2 to sustain the generated motion. Furthermore, the current pulses are switched continuously from phase coils P2 to P3 and subsequently, from phase coil P3 to Pl to maintain rotation of the rotor 408. Such a commutation is implemented in a repeated manner to maintain the rotor 408 of the electrical motor 100 rotating in a given rotation direction. Specifically, the phase coils Pl, P2 and P3 are beneficially energized in sequence as the rotor 408 rotates, and the coils Pl, P2 and P3 are not energized simultaneously, namely only one commutated phase is energized at any given time. Optionally, the freewheeling period is in a range of 0.5 to 5.0 times a duration of energizing the coils Pl, P2 and P3. Furthermore, the freewheeling period is implemented between the switching of current between the phase coils. Alternatively, optionally, for obtaining a smoother torque, two adjacent phase coils, for example the phase coils Pl and P2, are simultaneously energized (namely, overlapping commutation) when the winding coils C straggles significantly between phases Pl and P2. Optionally, the electrical motor 100 is operated dynamically between such a digital manner of commutation and overlapping commutation, depending upon a rotation rate and output torque required to be delivered in operation by the electrical motor 100. By employing a suitable sequence of commutation, the electrical motor 100 is capable of being driven in a clockwise direction of rotation as well as in an anticlockwise direction of rotation.

Optionally, during commutation, current pulses are applied to the commutation windings of the at least electrical motor using pulsewidth modulation (PWM) technique. Specifically, a width of the current pulses in a current-time graph may be modulated to control

-26a speed of the at least one electrical motor and operation of the switching arrangement 416. Furthermore, by using pulse-width modulation power control, a rotation rate and/or torque characteristics of the electrical motor 100 can be controlled very precisely, enabling the electrical vehicle to exhibit extremely smooth and versatile power transmission to wheels thereof.

Optionally, the electrical vehicle includes a motor control arrangement (not shown) to control operation of the electrical motor 100 described herein. It will be appreciated that the electrical vehicle optionally includes only a single electrical motor 100 to provide the electrical vehicle with motive power. Alternatively, it will be appreciated that the electrical vehicle includes a plurality of electrical motors 100 to provide the electrical vehicle with motive power, for example an electric motor 100 for each rear wheel. Optionally, the electrical motor 100 is implemented in a highly compact form as an in-hub electrical motor. It will be appreciated that the term motor control arrangement used herein relates to hardware, software, firmware, or a combination of these, operable to control operation of the electrical motor 100. In one embodiment, the motor control arrangement is implemented using hardware that is operable to execute a software application thereon. In one example, the software application is associated with a software application management and infotainment arrangement that is operable to control operation of the electrical motor 100.

Optionally, the motor control arrangement includes the rotor excitation unit 404 to couple electrical power from a battery arrangement 402 of the electrical vehicle to a resonant inductive power coupling arrangement 406, wherefrom the electrical power is coupled to a rotor 408 of the electrical motor 100 for generating a

-27rotor magnetic field. In such an instance, the rotor magnetic field is operable to interact in operation with the commutated magnetic field of the stator 410 of the electrical motor 100. In such an instance, the rotor excitation unit 404 is operable to convert a direct current from the battery arrangement 402 into an alternating current (AC) that is coupled to the resonant inductive power coupling arrangement 406. Furthermore, the motor control arrangement may control functioning of the switching elements SI, S2 and S3 of the switching arrangement 416.

Optionally, the rotor excitation unit 404 includes a resonant oscillator circuit, wherein the resonant oscillator circuit 418 includes a tunable capacitor 420, a transformer 422 including a primary winding and a secondary winding, and two push-pull transistors 424 and 426. In such an instance, the tunable capacitor 420 and the primary winding of the transformer 422 constitute a tank circuit that is tunable to a resonant frequency. Optionally, the transformer 422 is implemented as a compact ferrite core toroidal transformer. Furthermore, optionally, the two push-pull transistors 424 and 426 are driven in mutual anti-phase at the resonant frequency of the resonant oscillator circuit 418. More optionally, the two push-pull transistors 424 and 426 are implemented by way of silicon carbide transistors. In one example, the switching elements SI, S2, S3 of the switching arrangement 410 are also implemented by way of silicon carbide transistors, for example as aforementioned.

Optionally, the resonant oscillator circuit 418 of the rotor excitation unit 404 operates in a frequency range of 50 kilohertz to 1 megahertz, as aforementioned. In such an instance, a frequency of the alternating current that is to be coupled to the resonant inductive

-28power coupling arrangement 406 lies within the aforesaid frequency range.

Optionally, a bypass capacitor 428 is provided across the rotor excitation unit 404, in order to remove stray alternating current noise within the direct current provided from the battery arrangement 402, and also to allow for a high amplitude of current pulses to be applied to the stator windings when the electrical motor 100 is commutation in a digital manner as elucidated in the foregoing. Consequently, use of such a bypass capacitor 428 allows for filtering (of noise) the direct current received by the rotor excitation unit 404 and consequently allows for filtering (of noise) the alternating current that is to be coupled to the resonant inductive power coupling arrangement 406. The bypass capacitor 428 also allows for maintenance of the rotor magnetic field as the stator windings are digital commutated, while utilizing current from the battery arrangement 402 in a frugal efficient manner.

The electrical motor arrangement of the present disclosure includes the at least one electrical motor, as aforementioned. Furthermore, the at least one electrical motor includes the stator, the stator including one or more planar stator element, for example implemented as radial plate-like elements. Moreover, the at least one electrical motor includes the rotor, the rotor including one or more planar rotor elements, for example implemented as radial platelike elements, attached to the rotor shaft. Additionally, the one or more planar stator elements and the one or more planar rotor elements are arranged to have electrical winding coil arrangements disposed thereon. Such an arrangement of electrical coil windings on the one or more planar stator elements eliminates a requirement to include permanent magnets (such as rare-earth magnets) thereon.

-29It will be appreciated that such elimination of requirement of permanent magnets on the stator enables the at least one electrical motor to be provided in a lightweight design and moreover, is associated with a low manufacturing cost. Furthermore, the arrangement of the at least one electrical motor including the one or more planar stator elements and rotor elements enables to provide the magnetic field substantially orthogonally, for example orthogonal, to the principal surface planes of the one or more planar stator elements and rotor elements. It will be appreciated that providing such a magnetic field enables improved concentration of the magnetic field along the one or more radial planar rotor elements. Consequently, an efficiency associated with the at least one electrical motor is increased. Moreover, implementation of the stator and the rotor using the one or more planar stator elements and rotor elements enables an improved cooling within the at least one electrical motor, for example, by allowing air flow in gaps formed between the one or more planar stator elements and rotor elements. Therefore, a requirement for the at least one electrical motor to be externally cooled is reduced, because heat is more efficiently coupled to the casing of the at least one electrical motor. Consequently, the at least one electrical motor can be made to be lightweight and compact. Furthermore, the at least one electrical motor is associated with a low manufacturing cost and also, improved power consumption due to reduced power requirement for operation of external cooling equipment. Moreover, the at least one electrical motor includes the magnetic bearings coupled to the ends of the rotor shaft. Such magnetic bearings enable wear of the at least one electrical motor to be reduced due a reduction or avoidance of physical contact of components having relative motion therebetween. Consequently, an operating life of the at least one electrical motor is increased.

-30Therefore, it will be appreciated that the present disclosure provides a low cost, lightweight and compact motor arrangement including the at least one electrical motor, for use in an electrical vehicle. Conveniently, the at least one electrical motor is implemented as an in-hub motor. Alternatively, the at least one electrical motor is implemented as a chassis-mounted device whose rotor is coupled via flexible link to drive one or more wheels of the electrical vehicle, wherein the one or more wheels are supported on a suspension arrangement, such that the at least one electrical motor is effectively a sprung mass.

In the forgoing, it will be appreciated that the stator of the at least one electrical motor circumferentially surrounds the rotor. However, in an alternative implementation, the rotor circumferentially surrounds the stator, wherein the stator is implemented along a central region of the at least one electrical motor.

Modifications to embodiments of the present disclosure described in the foregoing are possible without departing from the scope of the present disclosure as defined by the accompanying claims. Expressions such as including, comprising, incorporating, have, is used to describe and claim the present disclosure are intended to be construed in a non-exclusive manner, namely allowing for items, components or elements not explicitly described also to be present. Reference to the singular is also to be construed to relate to the plural.

Claims

1. An electrical motor arrangement for an electrical vehicle, the electrical motor arrangement including at least one electrical motor, characterized in that the at least one electrical motor includes:

5 - a casing;

- a stator mounted on the casing, the stator including one or more planar stator elements extending from the casing, wherein each of the one or more planar elements includes a central hole; and

- a rotor including

10 - a rotor shaft that is disposed within the central hole of each of the one or more planar stator elements of the stator; and

- one or more planar rotor elements attached to the rotor shaft;

wherein principal planes of the one or more planar stator and rotor elements are arranged mutually to abut with a magnetic separation

15 gap therebetween, and the one or more planar stator elements and the one or more planar rotor elements are arranged to have electrical winding coil arrangements disposed thereon; and a bearing arrangement that rotationally supports the rotor relative to the stator.

20

2. An electrical motor arrangement of claim 1, characterized in that bearing arrangement includes magnetic bearings to support the rotor shaft relative to the stator.

3. An electrical motor arrangement of claim 1, characterized in that the bearing arrangement includes a combination of magnetic

-32bearings and mechanical bearings to support the rotor relative to the stator.

4. An electrical motor arrangement of claim 2 or 3, characterized in that the magnetic bearings are coupled to ends of the rotor shaft.

5 5. An electrical motor arrangement of claim 2, 3 or 4, characterized in that the magnetic bearings of the bearing arrangement include at least one permanent magnet.

6. An electrical motor arrangement of any one of claims 1 to 5, characterized in that the at least one electrical motor is operable to

10 function as a digitally-commutated electrical motor, wherein, during commutation, current pulses are applied to commutation windings of the at least one electrical motor, and a free-wheeling period is implemented between application of the current pulses during which the commutation windings are non-energized.

15

7. An electrical motor arrangement of claim 6, characterized in that during commutation, current pulses are applied to the commutation windings of the at least electrical motor using pulsewidth modulation (PWM).

8. An electrical motor arrangement of any one of the claims 1 to

20 7, characterized in that the at least one electrical motor includes nonpermanent-magnet ferrite elements and/or ferromagnetic laminate elements for defining a torque-generating magnetic field for the at least one electrical motor when in operation.

9. An electrical motor arrangement of any one of the claims 1 to

25 8, characterized in that a resonant inductive power coupling arrangement is employed to couple electrical power to a rotor of the at least one electrical motor for generating a rotor magnetic field that

-33is operable to interact in operation with a commutated magnetic field of a stator of the at least one electrical motor to generate output torque from the at least one electrical motor.

10. An electrical motor arrangement of claim 9, characterized in

5 that the rotor includes a rectifier arrangement for converting resonant inductively coupled power received at the rotor into direct current to generate the rotor magnetic field.

11. An electrical motor arrangement of any one the preceding claims, characterized in that the rotor is operable to rotate at a

10 maximum rotation rate in a range of 30000 rotations per minute (r.p.m.) to 100000 rotations per minute (r.p.m.).

12. An electrical motor arrangement to any one the preceding claims, characterized in that the rotor of the at least one electrical motor is further provided with mechanical bearings that bears the

15 rotor relative to the stator when the magnetic bearings are loaded to cause at least a portion of a gap of the magnetic bearings to be mechanically contacted.

13. An electrical motor arrangement of any one of the preceding

25 claims, characterized in that the stator is provided with a silicon carbide transistor switching arrangement for switching commutation magnetizing currents supplied to the stator when in operation.

Intellectual

Property

Office

Application No: GB1714896.6

13. An electrical motor arrangement of any one of the preceding claims, characterized in that the magnetic separation gap is in a range

20 of 0.1 mm to 10.0 mm.

14. An electrical motor arrangement of any one of the preceding claims, characterized in that the electrical winding coil arrangements are implemented using printed circuit board conductive tracks.

15. An electrical motor arrangement according to any one of the

25 preceding claims, characterized in that one or more planar rotor elements include a peripheral edge reinforcement arrangement for

-34converting radial forces acting upon the rotor when rotating in operation into corresponding circumferential forces.

16. An electrical motor arrangement of claim 15, characterized in that the peripheral edge reinforcement arrangement includes a

5 carbon fiber ring.

17. An electrical motor arrangement of any one of the preceding claims, characterized in that the stator is provided with a silicon carbide transistor switching arrangement for switching commutation magnetizing currents supplied to the stator when in operation.

10 18. An electrical motor arrangement for an electrical vehicle, the electrical motor arrangement including at least one electrical motor, characterized in that the at least one electrical motor includes:

- a motor casing;

- a stator mounted centrally relative to the motor casing, the stator

15 including one or more planar stator elements extending outwardly therefrom; and

- a rotor that encircles the stator, wherein the rotor includes

- a rotor shaft attached to a rotor casing; and

- one or more planar rotor elements attached to the rotor casing,

20 wherein each of the one or more planar rotor elements is provided with a central hole therein for accommodating the stator;

wherein principal planes of the one or more planar stator and rotor elements are arranged mutually to abut with a magnetic separation gap therebetween, and the one or more planar stator elements and

-35the one or more planar rotor elements are arranged to have electrical winding coil arrangements disposed thereon; and a bearing arrangement that rotationally supports the rotor relative to the stator.

5 19. An electrical motor arrangement of claim 18, characterized in that the bearing arrangement includes magnetic bearings to support to rotor shaft relative to the stator.

20. An electrical motor arrangement of claim 18, characterized in that the bearing arrangement includes a combination of magnetic

10 bearings and mechanical bearings to support the rotor shaft relative to the stator.

21. An electrical motor arrangement of claim 19 or 20, characterized in that the magnetic bearings are coupled to at least one end of the rotor shaft.

15 22. An electrical motor arrangement of any one of claims 18 to 21, characterized in that the at least one electrical motor is operable to function as a digitally-commutated electrical motor, wherein, during commutation, current pulses are applied to commutation windings of the at least one electrical motor, and a free-wheeling period is

20 implemented between application of the current pulses during which the commutation windings are non-energized.

23. An electrical motor arrangement of claim 22, characterized in that during commutation, current pulses are applied to the commutation windings of the at least electrical motor using pulse25 width modulation (PWM).

-3624. An electrical motor arrangement of any one of the claims 18 to

23, characterized in that the at least one electrical motor includes non-permanent-magnet ferrite elements and/or ferromagnetic laminate elements for defining a torque-generating magnetic field for

5 the at least one electrical motor when in operation.

25. An electrical motor arrangement of any one of the claims 18 to

24, characterized in that a resonant inductive power coupling arrangement is employed to couple electrical power to a rotor of the at least one electrical motor for generating a rotor magnetic field that

10 is operable to interact in operation with a commutated magnetic field of a stator of the at least one electrical motor to generate output torque from the at least one electrical motor.

26. An electrical motor arrangement of claim 25, characterized in that the rotor includes a rectifier arrangement for converting resonant

15 inductively coupled power received at the rotor into direct current to generate the rotor magnetic field.

27. An electrical motor arrangement of any one of claims 18 to 26, characterized in that the rotor is operable to rotate at a maximum rotation rate in a range of 30000 rotations per minute (r.p.m.) to

20 100000 rotations per minute (r.p.m.).

28. An electrical motor arrangement of claim 18, characterized in that the bearing arrangement includes magnetic bearings that include at least one permanent magnet.

29. An electrical motor arrangement to any one of claims 18 to 28,

25 characterized in that the rotor of the at least one electrical motor is further provided with mechanical bearings that bears the rotor relative to the stator when the magnetic bearings are loaded to cause

-37at least a portion of a gap of the magnetic bearings to be mechanically contacted.

30. An electrical motor arrangement of any one of claims 18 to 29, characterized in that the magnetic separation gap is in a range of 0.1

5 mm to 10.0 mm.

31. An electrical motor arrangement of any one of claims 18 to 30, characterized in that the electrical winding coil arrangements are implemented using printed circuit board conductive tracks.

32. An electrical motor arrangement of any one of claims 18 to 31, 10 characterized in that the rotor casing includes at least one peripheral edge reinforcement arrangement including a carbon fiber ring for constraining centrifugal forces acting upon the rotor casing when the at least one electrical motor is in operation.

33. An electrical motor arrangement of any one of claims 18 to 32, 15 characterized in that the stator is provided with a silicon carbide transistor switching arrangement for switching commutation magnetizing currents supplied to the stator when in operation.

Amendments to the claims have been filed as follows:

25 06 18

5 - a casing;

- a rotor including

- one or more planar rotor elements attached to the rotor shaft;

wherein principal planes of the one or more planar stator and rotor 15 elements are arranged mutually to abut with a magnetic separation gap therebetween, and the one or more planar stator elements and the one or more planar rotor elements are arranged to have electrical winding coil arrangements disposed thereon; and wherein the one or more planar rotor elements are tapered as a 20 function of radial distance from the elongate axis of the rotor shaft, wherein the one or more planar rotor elements are thicker where they are adjoined to the rotor shaft and thinner at their distal circumferential edge remote from the rotor shaft, and the one or more planar stator elements are correspondingly inversely tapered

25 06 18 such that they are thicker where they adjoin to the casing and thinner at their distal edge remote from the casing; and

5 2. An electrical motor arrangement of claim 1, characterized in that bearing arrangement includes magnetic bearings to support the rotor shaft relative to the stator.

10 bearings and mechanical bearings to support the rotor relative to the stator.

5. An electrical motor arrangement of claim 2, 3 or 4,

15 characterized in that the magnetic bearings of the bearing arrangement include at least one permanent magnet.

6. An electrical motor arrangement of any one of the claims 1 to 5, characterized in that a resonant inductive power coupling arrangement is employed to couple electrical power to a rotor of the

20 at least one electrical motor for generating a rotor magnetic field that is operable to interact in operation with a commutated magnetic field of a stator of the at least one electrical motor to generate output torque from the at least one electrical motor.

7. An electrical motor arrangement of any one the preceding

25 claims, characterized in that the rotor is operable to rotate at a maximum rotation rate in a range of 30000 rotations per minute

25 06 18 (r.p.m.) (or 3141.59265 radians per second) to 100000 rotations per minute (r.p.m.) (or 10471.975 radians per second).

8. An electrical motor arrangement of claim 2 or 3, characterized in that the rotor of the at least one electrical motor is further

5 provided with mechanical bearings that bears the rotor relative to the stator when the magnetic bearings are loaded to cause at least a portion of a gap of the magnetic bearings to be mechanically contacted.

9. An electrical motor arrangement of any one of the preceding

10 claims, characterized in that the magnetic separation gap is in a range of 0.1 mm to 10.0 mm.

10. An electrical motor arrangement of any one of the preceding claims, characterized in that the electrical winding coil arrangements are implemented using printed circuit board

15 conductive tracks.

11. An electrical motor arrangement according to any one of the preceding claims, characterized in that one or more planar rotor elements include a peripheral edge reinforcement arrangement for converting radial forces acting upon the rotor when rotating in

20 operation into corresponding circumferential forces.

12. An electrical motor arrangement of claim 11, characterized in that the peripheral edge reinforcement arrangement includes a carbon fiber ring.