GB2566685A

GB2566685A - Electrical vehicle and method of providing motive torque in electric vehicle using at least two electrical motors

Info

Publication number: GB2566685A
Application number: GB1714906.3A
Authority: GB
Inventors: lam Albert
Original assignee: Detroit Electric EV Technologies Zhejiang Ltd
Current assignee: Detroit Electric EV Technologies Zhejiang Ltd
Priority date: 2017-09-15
Filing date: 2017-09-15
Publication date: 2019-03-27
Anticipated expiration: 2037-09-15
Also published as: GB201714906D0; GB2566685B

Abstract

An electrical vehicle comprises at least one front wheel 104 and a pair of rear wheels 108 coupled to a frame arrangement 102. At least two electric motors 116,118 are coupled to the pair of rear wheels; are independently controlled to apply torque to corresponding rear wheels to propel the vehicle; and are implemented as sprung elements of the vehicle frame. Each motor can comprise a casing; a stator having planar stator elements and windings; and a rotor having a shaft, a planar element that has rotor windings and faces the stator element with a planar axial gap and magnetic bearings supporting the shaft. The motors can be digitally commutated by switching current pulses applied to the windings with a free-wheeling period between pulses. Power can be supplied to the rotor windings by resonant inductive power transfer via rectifiers. Each motor can be coupled to a rear wheel via a planetary gearbox 126, 128. Each motor can include a regenerative braking coil and a controller 120 can apply differential torque between left and right side rear wheels when the vehicle executes a turning maneuver.

Description

TORQUE IN ELECTRIC VEHICLE USING AT LEAST TWO ELECTRICAL MOTORS

TECHNICAL FIELD

The present disclosure relates generally to vehicles; more specifically, the present relates to electrical vehicles including vehicle frame arrangements, at least one front wheel and a pair of rear wheels rotatably coupled onto such vehicle frame arrangements, and an electrical motor arrangement for providing motive power to the electric vehicles. Furthermore, the present disclosure also relates to methods of providing motive torque in the aforementioned electrical vehicles.

BACKGROUND

Recently, in human history, vehicles have become an integral part of daily life. Such vehicles, and specifically automobiles, have introduced convenience and comfort to address human transportation needs. Contemporarily, automobiles are capable of traversing distances of several hundred miles or kilometres in relatively short periods of time, for example within a few hours. With advancements in the automobile technology, manufacture of electrical vehicles is now being manufactured in increasing numbers.

Electrical vehicles are potentially capable of playing a significant role in reducing environmental pollution and encouraging sustainable technologies. Typically, the electrical vehicles produce fewer by-products that cause anthropogenic climate change in comparison to conventional vehicles powered by fossil fuels, especially when the electrical vehicles are powered from renewable energy sources such as wind turbines, hydroelectric generators, tidal power generators, geothermal power generator, solar power generators and such like. However, it has been appreciated that electrical vehicles of superlative performance have to be manufactured to encourage the use of electrical vehicles in place of corresponding-performance internal combustion engine vehicles.

Generally, contemporary electrical vehicles include high performance vehicles which utilize powerful motor arrangements and provide brisk accelerations when in operation. Usually, such motor arrangements are prone to overheating issues while providing high operational torque to the electrical vehicle. Such overheating issues may severely affect performance and efficiency of the electrical vehicle. Furthermore, conventional motor arrangements used in electrical vehicles are known to include a stator that employs permanent magnets. However, use of such permanent magnets leads to a large and heavy design of the motor arrangements that may adversely affect weight and stability of the electrical vehicle. Furthermore, to provide high performance, such stators may include rare-earth magnets that leads to high manufacturing costs associated with the motor arrangements and consequently, high manufacturing costs associated with the electrical vehicle. Often, the motor arrangements employ a single electrical motor and a differential element to provide torque to wheels of the electrical vehicle. However, use of the single electrical motor and the separate differential element increases weight of the electrical vehicle.

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

SUMMARY

The present disclosure seeks to provide an improved electrical vehicle.

The present disclosure also seeks to provide an improved method of providing motive torque in an electrical vehicle.

According to a first aspect, an embodiment of the present disclosure provides an electrical vehicle including a vehicle frame arrangement, at least one front wheel and a pair of rear wheels rotatably coupled onto the vehicle frame arrangement, and an electrical motor arrangement for applying in operation torque to at least the pair of rear wheels to propel the electrical vehicle in a forward or a reverse direction, characterized in that:

(i) the electrical motor arrangement includes at least two electrical motors for applying in operation torque to the at least the pair of rear wheels;

(ii) the at least two electrical motors are mutually independently controllable from a motor control arrangement of the electrical vehicle; and (iii) the at least two electrical motors are implemented as a sprung element of the vehicle frame arrangement and are coupled via a coupling arrangement to their corresponding wheels.

The electrical vehicle of the present disclosure includes a substantially 20 lighter electrical motor arrangement as compared to motor arrangements of conventional electrical vehicles. Furthermore, owing to arrangement and operation of components within the electrical vehicle described herein, such an electrical vehicle is substantially lighter in weight, less prone to overheating issues, and has good balance whilst being driven.

According to a second aspect, an embodiment of the present disclosure provides a method of providing motive torque in an electrical vehicle including a vehicle frame arrangement, at least one front wheel and a pair of rear wheels rotatably coupled onto the vehicle frame arrangement, and an electrical motor arrangement for applying in operation torque to at least the pair of rear wheels to propel the electrical vehicle in a forward or a reverse direction, characterized in that the method includes:

(i) arranging for the electrical motor arrangement to include at least two electrical motors for applying in operation torque to the at least the pair of rear wheels;

(ii) arranging for the at least two electrical motors to be mutually independently controllable from a motor control arrangement of the electrical vehicle; and (iii) arranging for the at least two electrical motors to be implemented as a sprung element of the vehicle frame arrangement and to be coupled via a coupling arrangement to their corresponding wheels.

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 OF THE 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 disclosed 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 a plan view illustration of an electrical vehicle, in accordance with an embodiment of the present disclosure;

FIG. 2 is a schematic illustration of a block diagram depicting components of the electrical vehicle, in accordance with an embodiment of the present disclosure; and

FIG. 3 is an illustration of steps of a method of providing motive torque 15 in an electric vehicle, 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 non-underlined number to the item. When a number is non-underlined 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 an electrical vehicle. Furthermore, embodiments of the present disclosure are concerned with a method of providing motive torque in the electrical vehicle.

Referring to FIG. 1, there is shown a plan view illustration of an electrical vehicle 100, in accordance with an embodiment of the present disclosure. The electrical vehicle 100 includes a vehicle frame arrangement 102, at least one front wheel (depicted as a pair of steerable front wheels 104 and 106) and a pair of rear wheels (depicted as rear wheels 108 and 110), rotatably coupled onto the vehicle frame arrangement 102, and an electrical motor arrangement 112 for applying in operation torque to at least the pair of rear wheels 108 and 110 to propel the electrical vehicle 100 in a forward or a reverse direction. Additionally, or alternatively, optionally, the electrical motor arrangement 112 applies in operation torque to the at least one front wheel 104 and 106. Optionally, the at least front wheel 104 and 106 are provided with in-hub electrical motors for providing propulsion to the electrical vehicle 100; optionally, the in-hub electrical motors are mutually independently controllable. As shown, the front wheel 104 is a left front wheel, whereas the front wheel 106 is a right front wheel. Furthermore, as shown, the rear wheel 108 is a left rear wheel, whereas the rear wheel 110 is a right rear wheel.

Throughout the present disclosure, the term vehicle frame arrangement relates to a physical frame or structure to which various components (for example, such as engine, transmission, drive shaft, suspension and the like) of the electrical vehicle 100 are attached. Optionally, the vehicle frame arrangement 102 includes a platform to which a suspension system (now shown) of the electrical vehicle 100 is coupled, and a transverse beam member disposed transversely (namely, orthogonally relative to an elongate axis of the vehicle frame arrangement 102) at a location approximately mid-way along the vehicle frame arrangement 102. More optionally, the vehicle frame arrangement 102 includes an anti-roll bar (not shown). In such an instance, the anti-roll bar is configured to prevent rolling of the electrical vehicle 100 whilst the electrical vehicle 100 maneuvers sharp turns at a high speed.

Furthermore, as shown in FIG. 1, the at least one front wheel 104 and 106 is rotatably coupled onto the vehicle frame arrangement 102. Similarly, the pair of rear wheels 108 and 110 are rotatably coupled onto the vehicle frame arrangement 102. It will be appreciated that throughout the present disclosure, the term rotatably coupled relates to a circular movement of a given wheel around an axis (namely, about an axis of an axle associated therewith). Furthermore, optionally, the vehicle frame arrangement 102 is coupled with the front and rear wheel axles via mechanical bearings (not shown).

In an embodiment, the electrical vehicle 100 includes four wheels, namely a pair of front wheels 104 and 106 and the pair of rear wheels 108 and 110. In such an embodiment, the wheels 104-110 of the electrical vehicle 100 may be steered by employing a steering wheel 114 of the electrical vehicle 100. The steering wheel 114 is optionally coupled via a power-assisted steering arrangement (not shown) to the pair of front wheels 104 and 106. Optionally, such a power-assisted steering arrangement is controllable in accordance with preferences of a user of the electrical vehicle 100 and/or to driving conditions during use of the electrical vehicle 100 (for example, adaptively as a function of a speed of travel of the electrical vehicle 100, as a function of weather conditions to which the electrical vehicle 100 is confronted, road surface conditions and so forth).

Optionally, the at least one front wheel 104 and 106 is associated with a front suspension arrangement (not shown) and the pair of rear wheels

108 and 110 are associated with a rear suspension arrangement (not shown). Optionally, in this regard, the vehicle frame arrangement 102 of the electrical vehicle 100 includes coil springs having a predetermined stiffness corresponding to the front and rear suspension arrangements. In such an instance, the stiffness of the coil springs of the front and rear suspension arrangements allows for substantial compensation of vertical movement (or bounce) of the electrical vehicle 100 during operation thereof, and therefore, provides a more comfortable driving experience for the user of the electrical vehicle 100. Furthermore, optionally, at least one front wheel 104 and 106 and the pair of rear wheels 108 and 110 are mounted on parallel herring-bone suspension arrangements having corresponding spring and damper arrangements (not shown). Optionally, each of the spring and damper arrangements comprises a damper housed concentrically within a spring. In an example, the damper may be implemented as an oil damper, a piezo-electric stack active damper, a magnetic rheological damper, or any combination of these.

It will be appreciated that such spring and damper arrangements may be effective at mutually different frequency spectrum ranges, such that use of a combination of such spring and damper arrangements is capable of providing damping effectively over a greater frequency range, resulting in a more comfortable driving experience for the user of the electrical vehicle 100. In an example, the magnetic rheological damper employs magnetic-particles and oil mixture having at least an anti-coagulant, wherein damping characteristics of the magnetic rheological damper are optionally actively varied, namely adaptively varied, when driving to cope with different road surfaces and/or user preferences.

Optionally, the spring and damper arrangements corresponding to the front and rear suspension arrangements are mutually similar. Alternatively, optionally, the front suspension arrangement is associated with a simple oil-damper, whereas the rear suspension arrangement is associated with the magnetic rheological damper, whose operating characteristics can be adaptively varied depending upon driving conditions, travelling speed of the electrical vehicle 100, and so forth.

Furthermore, the electrical motor arrangement 112 includes at least two electrical motors, depicted as electrical motors 116 and 118 for applying in operation torque to the at least the pair of rear wheels 108 and 110, respectively. It will be appreciated that such in operation torque applied to at least the pair of rear wheels 108 and 110 allows for propelling the electrical vehicle 100 in the aforesaid forward direction or in the aforesaid reverse direction. In such an instance, the at least two electrical motors

116 and 118 receive electrical power from a battery arrangement 122 of the electrical vehicle 100 to provide a rotational force to at least the pair of rear wheels 108 and 110 for producing a rotational motion therein for propelling the electrical vehicle 100. Optionally, the at least two electrical motors 116 and 118 are operable to provide in operation torque to the at least one front wheel 104 and 106. Alternatively, optionally, the at least one front wheel 104 and 106 are provided with in-hub electrical motors for providing motive power to propel the electrical vehicle 100.

Optionally, the battery arrangement 122 of the electrical vehicle 100 is implemented as a floor-mounted flat battery unit, or as an L-shaped battery unit mounted behind seats of the electrical vehicle 100. Furthermore, optionally, the battery arrangement 122 is supplemented with supercapacitors for providing for peaks in current demand, for example during rapid acceleration of the electrical vehicle 100 and/or during rapid regenerative braking of the electrical vehicle 100. Moreover, optionally, the battery arrangement 122 is mounted in proximity of the at least two electrical motors 116 and 118 of the electrical vehicle 100.

Furthermore, the at least two electrical motors 116 and 118 are mutually independently controllable from a motor control arrangement 120 of the electrical vehicle 100. 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 at least two electrical motors 116 and 118 of the electrical motor arrangement 112.

Furthermore, the motor control arrangement 120 allows for the at least two electrical motors 116 and 118 to be mutually independently controlled, and also allows for their manner of control to be mutually independently defined. As an example, the motor control arrangement 120 may control the at least two electrical motors 116 and 118 to provide a mutually different amount of electrical power thereto, resulting in a mutually different amounts of torque to be delivered to the pair of rear wheels 108 and 110 based upon a driving condition during use of the electrical vehicle 100;, for example, mutually different amounts of torque are useful utilized when grip of tires (tyres) of the pair of wheels

108 and 110 onto a road surface is compromised by snow, ice, mud or loose gravel (for example, to assist to recover from an unintended lateral sliding or spinning motion of the electrical vehicle 100).

Moreover, in the electrical vehicle 100, the at least two electrical motors 116 and 118 are implemented as sprung elements of the vehicle frame arrangement 102 and are coupled via their respective flexible torque coupling arrangements 124 and 125 to their corresponding rear wheels 108 and 110, respectively. As shown, the at least two electrical motors 116 and 118 are coupled via their respective torque coupling arrangements 124 and 125 to the pair of wheels' rear wheels 108 and

110, respectively. Throughout the present disclosure, the term sprung element of the vehicle frame arrangement relates to an element, whose mass is supported by the suspension system (namely, the front and rear suspension arrangements) of the electrical vehicle 100. Furthermore, as the at least two electrical motors 116 and 118 are mounted on the vehicle frame arrangement 102, and mass of the vehicle frame arrangement 102 is supported by the suspension system of the electrical vehicle 100, mass of the at least two electrical motors 116 and 118 is also supported by the suspension system of the electrical vehicle 100.

Furthermore, throughout the present disclosure the term flexible torque coupling arrangement, used herein, relates to at least one mechanical element that is operable, namely configured, to transmit in operation the torque generated by the at least two electrical motors 116 and 118 to their corresponding wheels 108 and 110. Furthermore, optionally, the coupling arrangements 124 and 125 are also configured to transmit in operation the torque generated by the at least two electrical motors 116 and 118 to the at least one front wheel 104 and 106. As aforementioned, alternatively, the at least one front wheel 104 and 106 are provided with in-hub electrical motors for providing motive force to propel the electrical vehicle 100.

Optionally, the coupling arrangements 124 and 125 include at least one gear box arrangement depicted as gear boxes 126 and 128; optionally, the gear boxes 126 and 128 are implemented as planetary gear arrangements, variomatic gear arrangements providing a continuously variable gearing ratio or similar. Optionally, the coupling arrangements

124 and 125 include at least one clutch member (not shown) for selectively coupling or decoupling torque transmission therethrough. Shafts (not shown) of the at least two electrical motors 116 and 118 is coupled to their respective at least one clutch member. The clutch member is further coupled to the gear box arrangements 126 and 128, wherein the gear box arrangements 126 and 128 are configured for providing in operation torque (namely, a geared output torque) to the at least the pair of rear wheels 108 and 110. The gear box arrangements 126 and 128 include an output shaft associated therewith for driving their respective at least the pair of rear wheels 108 and 110, for example, by employing flexible knuckle joints, for propelling the electrical vehicle 100 when in operation. Optionally, when the gear box arrangements 126 and 128 are operated in an automatic transmission mode, namely as a continuously-variable torque converter, the clutch member is used less frequently, but is nevertheless coordinated with operation of the gear box arrangements 126 and 128 to avoid any slippage occurring within the clutch member. Alternatively, when the gear box arrangements 126 and 128 are operated in a manual transmission mode, the gear box arrangements 126 and 128 have discrete gear ratios.

Optionally, the at least two electrical motors 116 and 118 are implemented as in-hub electrical motors. In such an instance, for a given rear wheel (for example, such as the rear wheel 108), its corresponding electrical motor (for example, such as the electrical motor 118) and its corresponding gear box arrangement (for example, such as the gear box arrangement 126) are implemented as an in-hub arrangement.

Optionally, the electrical vehicle 100 includes two front wheels 104 and 106 and two rear wheels 108 and 110, wherein the two rear wheels 108 and 110 are provided with corresponding two rear electrical motors 116 and 118 mounted onto the vehicle frame arrangement 102, such that the two rear electrical motors 116 and 118 are implemented as sprung mass of the electrical vehicle 100, and coupled to their respective wheels 108 and 110 via a flexible torque-coupling arrangement (for example, such as the coupling arrangements 124 and 125).

Optionally, the flexible torque-coupling arrangement includes two torque coupling members (not shown) associated with the pair of rear wheels

108 and 110. More optionally, the flexible torque-coupling arrangement may be provided by using at least one coupling member including, but not limited to, jaw-type coupling, Oldham Coupling and/or universal joints. Beneficially, the flexible torque-coupling arrangement accommodates misalignment between shafts of the at least two electrical motors 116 and 118 under different load conditions.

Optionally, the motor control arrangement 120 is operable to apply differential torque between right-side wheels (for example, such as the right-side wheel 110) and left-side wheels for example, such as the leftside wheel 108) of the electrical vehicle 100 when the electrical vehicle

100 executes turning maneuvers when in operation. The electrical motor control arrangement 120 applies differential torque between the rightside rear wheel 110 and the left-side rear wheel 108 of the electrical vehicle 100 when the electrical vehicle 100 executes turning maneuvers when in operation. Throughout the present disclosure, the term 'differential torque' used herein relates to provision of different amounts of torque to different wheels of the electrical vehicle 100. As an example, in an event wherein the electrical vehicle 100 is maneuvered in a left direction, the motor control arrangement 120 is configured to control electrical power provided to the left-side rear wheel 108 and the rightside rear wheel 110 in a manner that the motor control arrangement 120 provide more electrical power to the right-side rear wheel 110 in order to generate more torque therein, as compared to the left-side rear wheel 108. This may be attributed to the fact that the right-side rear wheel

110 is required to traverse a larger distance as compared to the left-side rear wheel 108 while maneuvering in the left direction. Similarly, as another example, in an event wherein the electrical vehicle 100 is maneuvered in a right direction the motor control arrangement 120 is configured to control electrical power provided to the left-side rear wheel

108 and the right-side rear wheel 110 in a manner that the motor control arrangement 120 provides more electrical power to the left-side rear wheel 108 in order to generate more torque therein, as compared to the right-side rear wheel 110. This may be attributed to the fact that the leftside rear wheel 108 is required to traverse a larger distance as compared to the right-side rear wheel 110 while maneuvering in the right direction.

Optionally, each of the at least two electrical motors 116 and 118 includes a casing (not shown). The casing is operable to accommodate components of the each of the at least two electrical motors 116 and 118, as described herein below. In one example, the casing is implemented as a hollow cylindrical structure that is operable to accommodate the components of the each of the at least two electrical motors 116 and 118. In another example, the casing is implemented as a hollow cylindrical structure including a plurality of cylindrical portions, for example two semi-cylindrical halves. In such an instance, the semicylindrical halves are operable to be arranged, namely mutually cooperate, along an abutting surface thereof, for example a planar surface thereof, to provide the casing. It will be appreciated that such an implementation of the casing including the semi-cylindrical halves enables convenient assembly (and/or disassembly) of the each of the at least two electrical motors 116 and 118 by enabling easy arrangement of the components of the each of the at least two electrical motors 116 and 118 therein. Furthermore, optionally, the each of the at least two electrical motors 116 and 118 includes a stator (not shown) mounted on the casing. The stator is a stationary component of the each of the at least two electrical motors 116 and 118. Furthermore, the stator is operable to provide a magnetic field to enable operation of one or more components of the each of the at least two electrical motors 116 and 118. Moreover, optionally, the stator includes one or more planar stator elements, for example implemented as one or more radial plate-like elements having a circular periphery, extending from the casing, wherein each of the one or more planar stator elements includes a central hole, for example a central circular hole. In an example, the one or more planar stator elements are attached to an inner surface of the casing. In one example, the one or more planar stator elements are implemented as semi-circular half plates that are operable to be arranged to form the one or more planar stator elements. Additionally, optionally, the one or more planar stator elements includes a central hole that enables one or more components (such as the shaft) of each of at least two electrical motors 116 and 118 to be accommodated therein.

Furthermore, optionally, each of the at least two electrical motors 116 and 118 includes a rotor (not shown) including (i) a shaft that is disposed within the central hole of each of the one or more planar stator elements of the stator, and (ii) one or more planar rotor elements, for example implemented as one or more radial plate-like elements, attached to the shaft. Specifically, the rotor is a rotatable component of the each of the at least two electrical motors 116 and 118 that enables generation of torque, for example, to rotate at least the pair of rear wheels 108 and 110 associated with the electrical vehicle 100. In an embodiment, the rotors of the at least two electrical motors 116 and 118 are operable to rotate at a maximum rotation rate in a range of 30000 rotations per minute to 100000 rotations per minute. It will be appreciated that such a high maximum rotation rate of the rotors enables a high speed operation of the each of the at least two electrical motors 116 and 118, as well as enabling the at least two electrical motors 116 and 118 to be constructed in a very compact format and yet able to generate mechanical output power of up to, for example, 150 kW each. By very compact format is meant, for example, a casing length in a range of 30 cm to 50 cm, and a casing outer diameter in a range of 25 cm to 40 cm, with an overall motor weight in a range of 4 kg to 15 kg. For example, such high rotation rate of the rotors enables high rate of change of flux associated with a magnetic field of the stators of the each of the at least two electrical motors 116 and 118. Additionally, optionally, the shaft of the rotor is implemented as a cylindrical structure that is operable to rotate around an axis (such as an axis passing through center of the cylindrical shaft). Furthermore, the rotor includes one or more planar rotor elements attached to the shaft. Furthermore, the one or more radial plate-like rotor elements are attached to the shaft of the rotor along the axis thereof.

In such a case, the one or more planar stator elements and the one or more planar rotor elements are associated with principal planes that are arranged mutually to abut with a magnetic separation gap therebetween so that the rotor is able to rotate relative to the stator. For example, the one or more planar rotor elements are attached to the shaft such that the one or more planar rotor elements are positioned alternately with the one or more planar stator elements of the stator. In such an instance, it will be appreciated that the one or more planar stator elements do not obstruct the rotation of the rotor as the one or more radial plate-like rotor elements of the rotor are disposed in a gap formed by two adjacent planar stator elements. It will be appreciated that such an arrangement of the one or more planar stator elements and the one or more planar rotor elements enables formation of the magnetic separation gap therebetween. For example, the magnetic separation gap is defined by distance between principal planes of the one or more planar stator elements and the one or more planar stator elements.

Moreover, optionally, the one or more planar, namely radial plate-like, stator and rotor elements are arranged to have electrical winding coil arrangements disposed thereon. In one example, the one or more planar stator elements are arranged to have electrical winding coil arrangements disposed thereon. Such electrical winding coil arrangements enable to provide a magnetic field that interacts with a magnetic field generated by corresponding one or more planar stator elements, to enable the rotation of the rotors of the each of the at least two electrical motors 116 and

118.

Furthermore, optionally, the each of the at least two electrical motors 116 and 118 includes magnetic bearings coupled to ends of the shaft of the rotor. For example, the rotor is operable to rotate at high maximum rotation rates, such as, 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 bearings are operable to prevent physical contact between the shaft and one or more other components of the at least two electrical motors 116 and 118, such as, the one or more planar stator elements. By employing such magnetic bearings, it is feasible, potentially, to avoid any wear-and-tear occurring in the at least two electrical motors 116 and

118, thereby providing them with exceptionally long duration maintenance-free operation.

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 WO2010/112930 A2 (High-speed electric system, applicant - Dyson Technology Ltd., UK). These highperformance compact digital motors employ rare-earth permanent magnets. Principles of digital commutation of electrical motors as described in the published patent document W02010/112930 A2 are hereby incorporated by reference to the document.

Furthermore, optionally, at least one, for example both, of the at least two electrical motors 116 and 118 is operable to function as a digitally15 commutated electrical motor, wherein, during commutation, current pulses are applied to commutation windings (not shown) of the at least two electrical motors 116 and 118, and a free-wheeling period is implemented between the current pulses during which the commutation windings are non-energized. It will be appreciated that such digital commutation is provided to generate motion in the at least one of the at least two electrical motors 116 and 118. Furthermore, digital commutation may be implemented using the digitally controlled current pulses. Specifically, the commutation windings of the at least one electrical motor of the at least two electrical motors 116 and 118 may comprise electrical winding coil arrangement (not shown) disposed on the one or more planar stator elements of the stator of such at least one motor. In an exemplary implementation, current pulses may be provided to a phase coil Pl of the commutation windings using a switching control unit, specifically, to a switching element SI for generating a motion in the rotor of such at least one electrical motor. Subsequently, the current pulses may be switched to a phase coil P2 of the commutation windings using a switching element S2 to sustain the generated motion. Furthermore, the current pulses may be switched continuously from phase coil Pl to P2, P2 to P3 and subsequently, P3 to Pl to maintain a rotational motion of the at least two electrical motors 116 and 118.

Specifically, the phase coils Pl, P2 and P3 are beneficially energized in sequence as the rotor rotates, and the coils Pl, P2 and P3 are not energized simultaneously, namely only one commutated phase is energized at any given time. Therefore, a free-wheeling period may be implemented between the switching of current between the phase coils.

Optionally, the at least two electrical motors 116 and 118 are coupled to a planetary gearbox arrangement, as aforementioned, for coupling a torque generated at the rotors to their corresponding wheels (namely, the wheel 108 corresponding to the electrical motor 116, and the wheel 110 corresponding to the electrical motor 118) of the electrical vehicle

100. As an example, the at least one gear box arrangement, depicted as gear boxes 126 and 128, may be the planetary gearbox arrangement. In an embodiment, the shafts of the at least two electrical motors 116 and 118 are directly coupled to the planetary gearbox arrangement, wherein the planetary gearbox arrangement is configured for providing a geared output torque. The planetary gearbox arrangement further includes output shafts thereof for driving at least the pair of rear wheels 108 and 110 for propelling the electrical vehicle 100 when in operation. Beneficially, the planetary gearbox arrangement provides multiple gear ratios from a compact size of gearbox casing. Furthermore, in such a example, use of the planetary gearbox arrangement allows for low transmission losses. In another embodiment, the shafts of the at least two electrical motors 116 and 118 are coupled to their aforementioned clutch members. The clutch members are further coupled to the planetary gearbox arrangement. Thereafter, the planetary gearbox arrangement transfers the geared output torque, via its output shaft, to at least the pair of rear wheels 108 and 110 for propelling the electrical vehicle 100 when in operation. Optionally, cog wheels of the planetary gear arrangement are manufactured using advanced 3D printing techniques for metal powder sintering of printed shapes, or using hydraulicallypressed sintered metal construction.

More optionally, the planetary gearbox arrangement includes a cascaded configuration of a plurality of planetary gears. Throughout the present disclosure the term cascaded configuration, used herein, relates to an arrangement of the plurality of planetary gears in a sequential, adjoining and compact manner. Beneficially, the cascaded configuration of a plurality of planetary gears allows for light weight and compact size of the coupling arrangement 112, while also providing for high gearing ratios to be achieved, for example in excess of 100 times rotation rate reduction.

Referring to FIG. 2, there is shown a block diagram depicting components of the electrical vehicle 100, in accordance with an embodiment of the present disclosure. As shown, the electrical vehicle 100 includes the battery arrangement 122, the motor control arrangement 120, and the electrical motor arrangement 112. As mentioned previously, the electrical motor arrangement 112 includes the at least two electrical motors 116 and 118 whose rotors are collectively depicted herein as rotors 202 and stators are collectively depicted herein as stators 204.

Optionally, as shown, the motor control arrangement 120 includes a rotor excitation unit 206 to couple electrical power from the battery arrangement 122 of the electrical vehicle 100 to a resonant inductive power coupling arrangement 208, wherefrom the electrical power is coupled wirelessly to the rotors 202 of the at least two electrical motors 116 and 118 for generating a rotor magnetic field that is operable to interact in operation with a commutated magnetic field of the stators 204 of the at least two electrical motors 116 and 118. In such an instance, the rotor excitation unit 206 is operable to convert a direct current from the battery arrangement 122 into an alternating current that is to be coupled to the resonant inductive power coupling arrangement 208. Such use of wireless resonant inductive power transfer within the at least two electrical motors 116 and 118 is highly innovative, for example via use of a subset of planar stator elements and correspondingly a subset of corresponding planar rotor elements, because a rectifier arrangement mounted on the rotors allows DC current to be generated on the rotors for generating a rotor magnetic field. This avoids in the at least two electrical motors 116 and 118 a need to utilize permanent magnets, for example rare-earth permanent magnets, that drastically reduces the cost of manufacturing the at least two electrical motors 116 and 118. Optionally, such resonant inductive power transfer to the rotors is implemented at a resonant frequency in a range of 50 kHz to 1 MHz.

Optionally, the rotor excitation unit 206 includes a resonant oscillator circuit (not shown), wherein the resonant oscillator circuit includes a tunable capacitor, a transformer including a primary winding and a secondary winding, and two push-pull transistors. In such an instance, the tunable capacitor and primary winding of the transformer constitute a tank circuit that is tunable to a resonant frequency. Optionally, the transformer is implemented as a compact ferrite ring core transformer. Furthermore, optionally, the two push-pull transistors are driven in mutual anti-phase at the resonant frequency of the resonant oscillator circuit. More optionally, the two push-pull transistors are implemented by way of silicon carbide transistors, although it will be appreciated that other types of solid state switching devices can be employed, for example D-MOS FETs, bipolar transistors, SCR's, thyristors and such like. Silicon carbide transistors are particular beneficial to employ because they are capable of switching large currents, for example in an order of 100 Amperes, with nanoseconds, while being able to withstand thereacross voltages in an order of 1000 Volts.

More optionally, the resonant oscillator circuit of the rotor excitation unit 206 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 power coupling arrangement 208 lies within the aforesaid frequency range.

Furthermore, optionally, a bypass capacitor (not shown) is provided across the rotor excitation unit 206, in order to remove stray alternating current noise within the direct current provided from the battery arrangement 122, and to allow for large peak stator commutation currents to be achieved when aforementioned digital commutation of the at least two electrical motors 116 and 118 is employed. Beneficially, use of such a bypass capacitor allows for purifying the direct current received by the rotor excitation unit 206 and consequently allows for purifying the alternating current that is to be coupled to the resonant inductive power coupling arrangement 208.

Optionally, the resonant inductive power coupling arrangement 208 includes at least a capacitor and at least one inductor.

Furthermore, optionally, the rotors 202 of the at least two electrical motors 116 and 118 include a rectifier arrangement 210 for converting resonant inductively coupled power received at the rotors 202 into a direct current to generate the rotor magnetic field, as aforementioned. In such an instance, the rectifier arrangement 210 is operable to receive the alternating current (AC) from the resonant inductive power coupling arrangement 208 via inductive coupling therebetween, and convert such alternating current into the direct current (DC) that is subsequently employed to generate the rotor magnetic field. As an example, the rectifier arrangement 210 may provide the converted direct current to the electrical winding coil arrangements disposed on the one or more pkanar rotor elements of the rotors 202. Optionally, the rectifier arrangement 210 is implemented by way of a bridge rectifier, for example a Silicon bridge rectifier.

Moreover, optionally, as shown in FIG. 2, the motor control arrangement 120 includes a switching control unit 212 for switching commutation magnetizing currents supplied to the stators 204 of the at least two electrical motors 116 and 118 when in operation. In such an instance, the switching control unit 212 is operable to control a switching arrangement (not shown) for controlling the aforesaid magnetizing currents. It will be appreciated that the switching control unit 212 is operable to control which of the commutation windings (namely, the electrical winding coil arrangement disposed on the one or more planar stator elements of the stators 204) of the at least two electrical motors 116 and 118 are to be controlled and a manner of controlling such commutation windings of the at least two electrical motors 116 and 118.

Such control allows a commutation rate and a magnitude of excitation currents applied in operation to the rotors and stators to be mutually independently controlled, for enable adaptive torque vs. rotation rates to be realized for the at least two electrical motors 116 and 118.

Optionally, the switching arrangement may be implemented by way of a plurality of silicon carbide transistors, for example as aforementioned.

Optionally, at least one, for example both, of the at least two electrical motors 116 and 118 includes a regenerative braking coil arrangement (not shown) for generating electrical power from the at least two electrical motors 116 and 118 when regenerative braking is applied in operation to recharge the battery arrangement 122 of the electrical vehicle 100. In an exemplary implementation, the switching control unit 212 is operable to energize selectively the regenerative braking coil arrangement, i.e. implemented as phase coils P4, for generating electrical power from at least two electrical motors 116 and 118 when regenerative braking is applied in operation to recharge the battery arrangement 122 of the electrical vehicle 100. Specifically, the motor control arrangement 120 detects when regenerative braking is applied in operation, for example by employing a sensor element such as a potentiometer. The application of the regenerative braking allows a rotor of the at least two electrical motors 116 and 118 to remain energized,

i.e. continue to draw electrical power from the battery arrangement 122, to generate a magnetic field. However, during regenerative braking, the phase windings Pl, P2 and P3 (as described in a previous example) are not energized by their respective switching elements SI, S2, S3, and the rotor excitation unit 206 is coupled directly across the battery arrangement 122. Furthermore, during regenerative braking, a switching element S4 (which may be implemented as a bypass silicon carbide transistor) is activated to cause coils C of the rotor of the at least two electrical motors 116, 118to be energized, to generate power in the regenerative braking coil arrangement, i.e. implemented as the phase coils P4, of a stator of the at least two electrical motors 116, 118. For example, during the regenerative braking, the rotor of at least two electrical motors 116 and 118 remains energized, which causes the coils C of the rotor of at least two electrical motors 116 and 118 to generate a rotating magnetic field around the regenerative braking coil arrangement, i.e. the phase coils P4. This in turn causes induced power to be generated on the phase coils P4, which can subsequently be rectified (using rectifiers, not shown) for use in recharging the battery arrangement 122. In an example, this may be achieved using an isolating switched inverter charging circuit.

Referring to FIG.3, there is shown an illustration of steps of a method 300 of providing motive torque in an electric vehicle (for example, such as the electric vehicle 100 of FIG. 1), in accordance with an embodiment of the present disclosure. At a step 302, an arrangement is made for an electrical motor arrangement to include at least two electrical motors (for example, such as the at least two electrical motors 116 and 118 shown in FIG. 1) for applying in operation torque to at least a pair of rear wheels. At a step 304, an arrangement is made for the at least two electrical motors to be mutually independently controllable from a motor control arrangement of the electric vehicle. At a step 306, an arrangement is made for the at least two electrical motors to be implemented as a sprung element of the vehicle frame arrangement and to be coupled via a coupling arrangement to their corresponding wheels.

The steps 302 to 306 are only illustrative and other alternatives can also be provided where one or more steps are added, one or more steps are removed, or one or more steps are provided in a different sequence without departing from the scope of the claims herein. Optionally, the method 300 includes arranging for the at least two electrical motors to include a casing; a stator mounted on the casing, the stator including one or more planar (for example, radial plate-like) stator elements extending from the casing, wherein each of the one or more planar stator elements includes a central hole; a rotor including (i) a shaft that is disposed within the central hole of each of the one or more planar stator elements of the stator and (ii) one or more planar (for example, radial plate-like) rotor elements attached to the shaft, wherein the one or more planar stator elements and the one or more planar rotor elements are associated with principal planes that are arranged mutually to abut with a magnetic separation gap therebetween, and the one or more planar stator and rotor elements are arranged to have electrical winding coil arrangements disposed thereon; and magnetic bearings coupled to ends of the shaft of the rotor. Optionally, the method 300 includes arranging for at least one of the at least two electrical motors 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 freewheeling period is implemented between the current pulses during which the commutation windings are non-energized. Furthermore, optionally, the method 300 includes arranging for the motor control arrangement to include a rotor excitation unit to couple wirelessly electrical power from a battery arrangement to a resonant inductive power coupling arrangement, wherefrom the electrical power is coupled to the rotors of the at least two electrical motors for generating a rotor magnetic field that is operable to interact in operation with a commutated magnetic field of the stators of the at least two electrical motors. Moreover, optionally, the method 300 includes arranging for the motor control arrangement to include a rectifier arrangement for converting resonant inductively coupled power received at the rotors into a direct current to generate the rotor magnetic field. Optionally, the method 300 includes arranging for the rotors of the at least two electrical motors to be operable to rotate at a maximum rotation rate in a range of 30000 rotations per minute to 100000 rotations per minute. Furthermore, optionally, the method 300 includes arranging for the motor control arrangement to include a switching control unit for switching commutation magnetizing currents supplied to the stators of the at least two electrical motors when in operation. Moreover, optionally, the method 300 includes arranging for at least one of the at least two electrical motors to be coupled to a planetary gearbox arrangement for coupling a torque generated at the rotors to its corresponding wheel of the electrical vehicle. Optionally, in this regard the method 300 includes arranging for the planetary gearbox arrangement to include a cascaded configuration of a plurality of planetary gears. Optionally, the method 300 includes arranging for at least one of the at least two electrical motors to include a regenerative braking coil arrangement for generating electrical power from the at least one electrical motor when regenerative braking is applied in operation to recharge the battery arrangement of the electrical vehicle. Furthermore, optionally, the method 300 includes arranging for the electrical vehicle to include two front wheels and two rear wheels, wherein the two rear wheels are provided with corresponding two rear electrical motors mounted onto the vehicle frame arrangement, such that the two rear electrical motors are implemented as sprung mass of the electrical vehicle, and coupled to their respective wheels via a flexible torquecoupling arrangement. Optionally, the method 300 includes arranging for the motor control arrangement to be operable to apply differential torque between right-side wheels and left-side wheels of the electrical vehicle when the electrical vehicle executes turning maneuvers when in operation. Optionally, the method includes providing one or more steered front wheels of the electrical vehicle with in-hub electrical motors for providing additional motive power to the electrical vehicle; optionally, the in-hub electrical motors are implemented as aforementioned using one or more planar rotor elements, one or more planar stator elements, wireless resonant inductive power coupling of power to the rotor for generating a rotor magnetic field, and digital commutation of winding arrangements of the one or more stator elements.

It will be appreciated in the method that use of such wireless resonant inductive power coupling to the rotor for generating the rotor magnetic field potentially avoids the electrical motors needing to utilize permanent magnets, for example avoiding a need to employ permanent magnets fabricated from rare-earth elements, namely materials.

Optionally, the one or more planar rotor elements and the one or more stator elements include paramagnetic material, for example ferromagnetic material, for providing a low-reluctance magnetic path within the electrical motors. The ferromagnetic material is beneficially a ferrite material having a relative permeability (μ_Γ) in a range of 10 to

10000, more optionally in a range of 20 to 1000; such a ferrite beneficially exhibits a low electrical conductivity to reduce eddy current losses therein when exposed to a temporally changing magnetic field. Alternatively, or additionally, the ferromagnetic material is beneficially implemented as a laminated structure of thin steel plates, for example, silicon steel plates as commonly used for manufacturing electrical transformers. Optionally, the thin steel plates have an individual thickness in a range of 0.1 mm to 1.0 mm. Optionally, an insulating polymeric material, for example an adhesive epoxy, is provided between the steel plates to reduce eddy current conduction therebetween.

The present disclosure provides the aforementioned electrical vehicle and the aforementioned method of providing motive torque in such an electrical vehicle. The described electrical vehicle includes an improved electrical motor arrangement as compared to motor arrangements of conventional electrical vehicles. Specifically, the electrical motor arrangement described herein allows for reduction of overheating whilst providing high operational torque to the electrical vehicle. Furthermore, the described electrical motor arrangement is substantially lighter in weight as compared to its conventional counterparts, and also allows for balancing the electrical vehicle without requiring a separate differential element. Beneficially, the method of the present disclosure is simple, reliable, and easy to implement.

Modifications to embodiments of the invention described in the foregoing are possible without departing from the scope of the invention as defined by the accompanying claims. Expressions such as including, comprising, incorporating, consisting of, have, is used to describe and claim the present invention 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. Numerals included within parentheses in the accompanying claims are intended to assist understanding of the claims and should not be construed in any way to limit subject matter claimed by these claims.

Claims

1. An electrical vehicle including a vehicle frame arrangement, at least one front wheel and a pair of rear wheels rotatably coupled onto the vehicle frame arrangement, and an electrical motor arrangement for applying in operation torque to at least the pair of rear wheels to propel the electrical vehicle in a forward or a reverse direction, characterized in that:

2. An electrical vehicle of claim 1, characterized in that each of the at least two electrical motors includes:

- 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 stator elements includes a central hole;

- a rotor including

- a 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 shaft;

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

- magnetic bearings coupled to ends of the shaft of the rotor.

3. An electrical vehicle of claim 2, characterized in that the planar elements are implemented as radial plate-like elements.

4. An electrical vehicle of claim 2 or 3, characterized in that at least

10 one of the at least two electrical motors 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 implemented between the current pulses during which the commutation windings are non15 energized.

5. An electrical vehicle of claims 2, 3 or 4, characterized in that the motor control arrangement includes a rotor excitation unit to couple electrical power wirelessly from a battery arrangement of the electrical

20 vehicle to a resonant inductive power coupling arrangement, wherefrom the electrical power is coupled to the rotors of the at least two electrical motors for generating a rotor magnetic field that is operable to interact in operation with a commutated magnetic field of the stators of the at least two electrical motors.

5. An electrical vehicle of claims 2, 3, 4 or 5, characterized in that the rotors of the at least two electrical motors include a rectifier arrangement for converting resonant inductively coupled power received at the rotors into a direct current (DC) to generate the rotor magnetic field.

7. An electrical vehicle of any one of claims 2 to 6, characterized in that the rotors of the at least two electrical motors are operable to rotate at a maximum rotation rate in a range of 30000 rotations per minute to 100000 rotations per minute.

8. An electrical vehicle of any one of claims 2 to 7, characterized in that the motor control arrangement includes a switching control unit for switching commutation magnetizing currents supplied to the stators of the at least two electrical motors when in operation.

9. An electrical vehicle of any one of claims 2 to 8, characterized in that at least one of the at least two electrical motors are coupled to a planetary gearbox arrangement for coupling a torque generated at the rotors to its corresponding wheel of the electrical vehicle.

10. An electrical vehicle of claim 9, characterized in that the planetary gearbox arrangement includes a cascaded configuration of a plurality of planetary gears.

20 11. An electrical vehicle of any one of the preceding claims, characterized in that at least one of the at least two electrical motors includes a regenerative braking coil arrangement for generating electrical power from the at least one electrical motor when regenerative braking is applied in operation to recharge the battery arrangement of the

25 electrical vehicle.

12. An electrical vehicle of any one of the preceding claims, characterized in that the electrical vehicle includes two front wheels and two rear wheels, wherein the two rear wheels are provided with

30 corresponding two rear electrical motors mounted onto the vehicle frame arrangement, such that the two rear electrical motors are implemented as sprung mass of the electrical vehicle, and coupled to their respective wheels via a flexible torque-coupling arrangement.

13. An electrical vehicle of any one of the preceding claims, wherein the motor control arrangement is operable (configured) to apply differential torque between right-side wheels and left-side wheels of the electrical vehicle when the electrical vehicle executes turning maneuvers when in operation.

14. A method of providing motive torque in an electrical vehicle including a vehicle frame arrangement, at least one front wheel and a pair of rear wheels rotatably coupled onto the vehicle frame arrangement, and an electrical motor arrangement for applying in operation torque to at least the pair of rear wheels to propel the electrical vehicle in a forward or a reverse direction, characterized in that the method includes:

15. A method of claim 14, characterized in that the method includes arranging for the at least two electrical motors to include:

- a casing;

- a rotor including

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

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

10 disposed thereon; and

- magnetic bearings coupled to ends of the shaft of the rotor.

16. A method of claim 15, characterized in that the method includes arranging for at least one of the at least two electrical motors to function

15 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 the current pulses during which the commutation windings are non-energized.

17. A method of claim 15 or 16, characterized in that the method includes arranging for the motor control arrangement to include a rotor excitation unit to couple wirelessly electrical power from a battery arrangement to a resonant inductive power coupling arrangement,

25 wherefrom the electrical power is coupled to the rotors of the at least two electrical motors for generating a rotor magnetic field that is operable to interact in operation with a commutated magnetic field of the stators of the at least two electrical motors.

30 18. A method of claims 15, 16 or 17, characterized in that the method includes arranging for the motor control arrangement to include a rectifier arrangement for converting resonant inductively coupled power received at the rotors into a direct current to generate the rotor magnetic field.

19. A method of any one of claims 15 to 18, characterized in that the

5 method includes arranging for the rotors of the at least two electrical motors to be operable to rotate at a maximum rotation rate in a range of 30000 rotations per minute to 100000 rotations per minute.

20. A method of any one of claims 15 to 19, characterized in that the

10 method includes arranging for the motor control arrangement to include a switching control unit for switching commutation magnetizing currents supplied to the stators of the at least two electrical motors when in operation.

15 21. A method of any one of claims 15 to 20, characterized in that the method includes arranging for at least one of the at least two electrical motors to be coupled to a planetary gearbox arrangement for coupling a torque generated at the rotors to its corresponding wheel of the electrical vehicle.

22. A method of claim 21, characterized in that the method includes arranging for the planetary gearbox arrangement to include a cascaded configuration of a plurality of planetary gears.

25 23. A method of any one of claims 14 to 22, characterized in that the method includes arranging for at least one of the at least two electrical motors to include a regenerative braking coil arrangement for generating electrical power from the at least one electrical motor when regenerative braking is applied in operation to recharge the battery arrangement of

30 the electrical vehicle.

24. A method of any one of the claims 14 to 23, characterized in that the method includes arranging for the electrical vehicle to include two front wheels and two rear wheels, wherein the two rear wheels are provided with corresponding two rear electrical motors mounted onto the

5 vehicle frame arrangement, such that the two rear electrical motors are implemented as sprung mass of the electrical vehicle, and coupled to their respective wheels via a flexible torque-coupling arrangement.

25. A method of any one of the claims 14 to 24, characterized in that

10 the method includes arranging for the motor control arrangement to be operable to apply differential torque between right-side wheels and leftside wheels of the electrical vehicle when the electrical vehicle executes turning maneuvers when in operation.

Amendments to the claims have been filed as follows

1903 18

1. An electrical vehicle including a vehicle frame arrangement, at least one front wheel and a pair of rear wheels rotatably coupled onto the vehicle frame arrangement, and an electrical motor arrangement for

5 applying in operation torque to at least the pair of rear wheels to propel the electrical vehicle in a forward or a reverse direction, characterized in that:

(i) the electrical motor arrangement includes at least two electrical motors for applying in operation torque to the at least the pair of rear io wheels;

(ii) the at least two electrical motors are mutually independently controllable from a motor control arrangement of the electrical vehicle; and (iii) the at least two electrical motors are implemented as a sprung

15 element of the vehicle frame arrangement and are coupled via a coupling arrangement to their corresponding wheels, wherein each of the at least two electrical motors includes:

- a casing;

- a stator mounted on the casing, the stator including one or more

20 planar stator elements extending from the casing, wherein each of the one or more planar stator elements includes a central hole;

- a rotor including

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

1903 18 wherein the one or more planar stator elements and the one or more planar rotor elements are associated with principal planes that are arranged mutually to abut with a magnetic separation gap therebetween, and the one or more planar stator and rotor elements

5 are arranged to have electrical winding coil arrangements disposed thereon; and

- magnetic bearings coupled to ends of the shaft of the rotor, wherein the motor control arrangement includes a rotor excitation unit to couple electrical power wirelessly from a battery arrangement of the

10 electrical vehicle to a resonant inductive power coupling arrangement, wherefrom the electrical power is coupled to the rotors of the at least two electrical motors for generating a rotor magnetic field that is operable to interact in operation with a commutated magnetic field of the stators of the at least two electrical motors.

15 2. An electrical vehicle of claim 1, characterized in that the planar elements are implemented as radial plate-like elements.

3. An electrical vehicle of claim 1 or 2, characterized in that at least one of the at least two electrical motors is operable to function as a digitally-commutated electrical motor, wherein, during commutation,

20 current pulses are applied to commutation windings of the at least one electrical motor, and a free-wheeling period is implemented between the current pulses during which the commutation windings are nonenergized.

4. An electrical vehicle of claims 1, 2, or 3, characterized in that the

25 rotors of the at least two electrical motors include a rectifier arrangement for converting resonant inductively coupled power received at the rotors into a direct current (DC) to generate the rotor magnetic field.

1903 18

5. An electrical vehicle of any one of claims 1 to 4, characterized in that the rotors of the at least two electrical motors are operable to rotate at a maximum rotation rate in a range of 30000 rotations per minute or (3141.59265 radian per second) to 100000 rotations per

5 minute or (10471.9755 radian per second).

6. An electrical vehicle of any one of claims 1 to 5, characterized in that the motor control arrangement includes a switching control unit for switching commutation magnetizing currents supplied to the stators of the at least two electrical motors when in operation.

10

7. An electrical vehicle of any one of claims 1 to 6, characterized in that at least one of the at least two electrical motors are coupled to a planetary gearbox arrangement for coupling a torque generated at the rotors to its corresponding wheel of the electrical vehicle.

8. An electrical vehicle of claim 7, characterized in that the planetary

15 gearbox arrangement includes a cascaded configuration of a plurality of planetary gears.

9. An electrical vehicle of any one of the preceding claims, characterized in that at least one of the at least two electrical motors includes a regenerative braking coil arrangement for generating

20 electrical power from the at least one electrical motor when regenerative braking is applied in operation to recharge the battery arrangement of the electrical vehicle.

10. An electrical vehicle of any one of the preceding claims, characterized in that the electrical vehicle includes two front wheels and

25 two rear wheels, wherein the two rear wheels are provided with corresponding two rear electrical motors mounted onto the vehicle frame arrangement, such that the two rear electrical motors are

1903 18 implemented as sprung mass of the electrical vehicle, and coupled to their respective wheels via a flexible torque-coupling arrangement.

11. An electrical vehicle of any one of the preceding claims, wherein the motor control arrangement is operable (configured) to apply

5 differential torque between right-side wheels and left-side wheels of the electrical vehicle when the electrical vehicle executes turning maneuvers when in operation.

12. A method of providing motive torque in an electrical vehicle including a vehicle frame arrangement, at least one front wheel and a

10 pair of rear wheels rotatably coupled onto the vehicle frame arrangement, and an electrical motor arrangement for applying in operation torque to at least the pair of rear wheels to propel the electrical vehicle in a forward or a reverse direction, characterized in that the method includes:

15 (i) arranging for the electrical motor arrangement to include at least two electrical motors for applying in operation torque to the at least the pair of rear wheels;

(ii) arranging for the at least two electrical motors to be mutually independently controllable from a motor control arrangement of the

20 electrical vehicle; and (Hi) arranging for the at least two electrical motors to be implemented as a sprung element of the vehicle frame arrangement and to be coupled via a coupling arrangement to their corresponding wheels, wherein the method includes arranging for the at least two electrical

25 motors to include:

- a casing;

1903 18

- a rotor including

5 - a 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 shaft;

wherein the one or more planar stator elements and the one or more planar rotor elements are associated with principal planes that are

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

- magnetic bearings coupled to ends of the shaft of the rotor,

15 wherein the method includes arranging for the motor control arrangement to include a rotor excitation unit to couple wirelessly electrical power from a battery arrangement to a resonant inductive power coupling arrangement, wherefrom the electrical power is coupled to the rotors of the at least two electrical motors for generating a rotor

20 magnetic field that is operable to interact in operation with a commutated magnetic field of the stators of the at least two electrical motors.

13. A method of claim 12, characterized in that the method includes arranging for at least one of the at least two electrical motors to

25 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

1903 18 implemented between the current pulses during which the commutation windings are non-energized.

14. A method of claims 12 or 13, characterized in that the method includes arranging for the motor control arrangement to include a

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

15. A method of any one of claims 12 to 14, characterized in that the method includes arranging for the rotors of the at least two electrical

10 motors to be operable to rotate at a maximum rotation rate in a range of 30000 rotations per minute or (3141.59265 radian per second) to 100000 rotations per minute or (10471.9755 radian per second).

16. A method of any one of claims 12 to 15, characterized in that the method includes arranging for the motor control arrangement to include

15 a switching control unit for switching commutation magnetizing currents supplied to the stators of the at least two electrical motors when in operation.

17. A method of any one of claims 12 to 16, characterized in that the method includes arranging for at least one of the at least two electrical

20 motors to be coupled to a planetary gearbox arrangement for coupling a torque generated at the rotors to its corresponding wheel of the electrical vehicle.

18. A method of claim 17, characterized in that the method includes arranging for the planetary gearbox arrangement to include a cascaded

25 configuration of a plurality of planetary gears.

19. A method of any one of claims 12 to 18, characterized in that the method includes arranging for at least one of the at least two electrical motors to include a regenerative braking coil arrangement for generating electrical power from the at least one electrical motor when regenerative braking is applied in operation to recharge the battery arrangement of the electrical vehicle.

20. A method of any one of the claims 12 to 19, characterized in that 5 the method includes arranging for the electrical vehicle to include two front wheels and two rear wheels, wherein the two rear wheels are provided with corresponding two rear electrical motors mounted onto the vehicle frame arrangement, such that the two rear electrical motors are implemented as sprung mass of the electrical vehicle, and coupled

10 to their respective wheels via a flexible torque-coupling arrangement.

o

CD

21. A method of any one of the claims 12 to 20, characterized in that the method includes arranging for the motor control arrangement to be operable to apply differential torque between right-side wheels and leftside wheels of the electrical vehicle when the electrical vehicle executes

15 turning maneuvers when in operation.

Intellectual

Property

Office