Description:FIELD OF INVENTION.
[0001] The present disclosure relates to the design of magnet- less multi rotor, multi stator electric motor that makes it highly efficient and helps meeting torque demand at various speed and load in an electric vehicle or any other application that requires motor as prime mover.

BACKGROUND AND PRIOR ART
[0002] In electric automobiles the torque demand for moving the vehicle is met by the electric motor connected to a battery pack. In most cases the automobiles have single motor as prime mover. Few electric automobile manufacturers moved to multiple motor technology where every wheel of the automobile is driven by individual motors.
In the case of single motor or multiple motors driven vehicles, the motor speed will reduce when load demands more torque to propel the vehicle. Electric motor consumes higher energy to meet peak torque requirement
[0003] Electric vehicles are fitted with motor/s that has power output to match the worst driving conditions. Because of this, the motor nominal power becomes high. Always the vehicle has to drive with a big motor irrespective of driving conditions. This consumes more power from the battery pack and reduces drive range.
[0004] To reduce power consumption and to increase the drive range in the case of an electric vehicle an ideal way is to have a small motor for small torque requirement, a medium size motor to deliver medium torque and a bigger motor to deliver higher torque.
[0005] This arrangement can be designed as a single motor with 3 rotor and three stator where each rotor stator combination will come in to action based on torque demand thus reducing the power consumption to the maximum which is the basis for the disclosed technology.
[0006] Reference can be made to CN205791876U The utility model relates to an electric automobile of hypertape control unit is with many windings permanent -magnet machine, including controller, binding post box, casing, rotor, stator core, end cover, bearing, multi -functional wire winding group and arcuation magnetic iron block. Above -mentioned many windings permanent -magnet machine traveles difference that the in -process probably meets to electric automobile.
[0007] Reference can be made to CN107394980A The invention discloses a multi-rotor multi-stator core-free motor stator structure. The structure comprises an end cover and a rotary shaft rotatably installed on the end cover, wherein mutually independent rotors are coaxially fixed to the rotary shaft at intervals in the axial direction, several stators which have the same winding are coaxially fixed to the end cover in the axial direction, at least three rotors are arranged

BRIEF DESCRIPTION OF THE DRAWINGS
[0008] Fig1 is the isometric view of
[0009] Fig 2 shows the multi-stage motor connected to the electronic multi-stage motor controller through wiring harness
[0010] Fig 3 shows the various parts of the multi-stage motor in exploded view
[0011] Fig 4 is the sectional view multi-stage motor showing the arrangement of stators, rotors and motor shaft respectively inside the motor casing.
PROBLEM TO BE SOLVED
[0012] All the above cited arts utilises motors which have magnets, however the novelty is in using magnet less rotors and stators. This avoid back emf from the non-powered stator and rotor while the powered rotor and stator is operating the non-powered ones. While using a rotor or stator with magnet, the back emf created by the non-powered rotor and stator create extra load on the powered rotor and the power consumption become more. More over the magnetic flux leakage problems are high in case of rotor and stator combination that uses magnet.
OBJECT OF INVENTION
[0013] Object of the invention is to develop a magnet-less Multi-stage (Multi rotor and stator) motors having highest efficiency,
[0014] Another object of the invention is to this invention is to reduce the heat generated during the working of motor.
[0015] Another object of the invention is to avoid back emf from the non-powered stator and rotor while the powered rotor and stator is operating the non-powered ones
SUMMARY OF THE INVENTION
[0016] The current invention discloses a multistage motor which consists of number of magnet-less rotors and equivalent number of magnet-less stators of different or same power capacity. The rotors are connected concentrically to the motor center shaft maintaining gap between each other. The equivalent stators are mounted on the motor outer casing.The technology lies in dividing a single rotor and stator of a normal motor in to multiple rotors and stators of different power output while maintaining the total power of single stator rotor motor and multi-stage motor same.
[0017] The power input of the motor is from an electronic controller unit which is connected to an electric power source such as a battery pack. The multi-stage motor works on the principle of switching ON and OFF the various stator and rotor or its combinations based on the torque requirement.
[0018] When power is supplied to the motor, the controller gives power to the lowest power rated rotor first and then to the second and to the third rotor and combinations of rotor and stator based on the torque required to operate the equipment or vehicle where the motor is connected. If the equipment is able to operate when powering the first rotor, the controller will not supply power to the other rotors there by saving energy.
[0019] When load increases the controller will start powering other rotors. This switching of power from one rotor to the other and combinations or powering all the rotors enable overall efficiency improvement.
DETAILED DESCRIPTION OF THE INVENTION
[0020] As shown in figure 3 and figure 4, the power output of rotor-stator combination (2) and (5) is lower than the combination (3) and (6). The power of (4) and (7) combination is the maximum. Based on torque requirement combinations of both first and second set and all the three sets of stators-rotors can be powered using the multi-stage motor controller. When low torque is required rotor stator combination (2) and (5) only operates and when more torque is required more rotor-stator combinations will get powered. The multi-stage motor is fabricated with provision for different adjustments.
[0021] In one or more embodiment, the multi-stage motor is operated by electric power supplied in a sequence to the various rotor and stator or its combinations. This sequence of power supply enable to consume less power than operating a single rotor and stator motor that provides sufficient torque. The output shaft of the multi-stage motor is connected to a gear box or to pulley or sprocket to drive the vehicle.
[0022] In one or more embodiment, the development of multi-stage motor for electric automobiles includes the design of different components of the motor, electronics circuit to operate the motor and selection of materials for fabrication of the designed unit.
In one or more embodiment, the motor casing is designed to fit the multiple stators. The casing is fabricated using aluminum alloy or other materials. The thickness of the gearbox casing is decided based on the strength required. The motor shaft is designed to hold the various rotors. The stators and rotors are designed to provide different or same power output. The motor shaft is fitted in to the motor casing using end covers that has bearing to provide free rotation of the shaft. Each stator and rotor is matched to produce particular power output. One end of the shaft is connected with a cooling fan and the other end can be connected to the gearbox. In figure 3 the rotors (2), (3) and (4) is fitted exactly above the stators (4), (5) and (6) when assembled
[0023] In one or more embodiment, the electrical connection to the multi-stage motor is provided through an electronics circuit that decides the power changing pattern based on the torque demand of the vehicle. The sensors connected to the electronic circuit analyses the speed and load of the vehicle. At low speeds the rotor and stator combination which is designated for lower power will get excited for providing the required torque. Other combinations of rotor and stator or a combination will get according to the torque demand. When the torque demand goes up more stator-rotor combinations will get powered. In one or more embodiment, an electronic motor controller unit is used for power transmission from battery pack to motor. In one or more embodiment, the multi-stage electric motor is designed to have minimum dimensions so that weight and material usage can be minimum. Also enables easy fitment.
[0024] In one or more embodiment, one end of the motor shaft is connected with a fan to cool the motor. The length of the motor shaft is optimized for maximum performance and power requirement.
[0025] In one or more embodiment, the end cover of motor casing will have provisions to mount the rotor shaft. The end covers are fitted together using suitable fasteners. When power is supplied to the winding of stator the corresponding rotor get energized and the shaft starts rotating along with the other rotors. When the electric motor starts operating the input shaft along with bearings the active multi-stage motor transmits torque from motor to the output shaft that is conned to the gear box. There are can many stator-motor combinations based on the power requirement that operates at pre-decided speed of the vehicle. The first rotor -stator operates at the lower power, the second at more power and the third at power more than the second. As the torque demand of the vehicle increases the switching between the rotor-stator combinations happens. This switching is done through an integrated circuit based electronics motor controller.
[0026] In one or more embodiment, the multi-stage motor rotor is a bearing mounted type where the stator is firmly mounted on the casing. The rotor rotates only when the stator or both stator and rotor is powered using suitable power source that matches. In one or more embodiment, the other assemblies such as the speed sensor circuit, encoders and bearings are mounted on the supporting casing. The multi-stage motor casing is put together using suitable fasteners. Additionally, while the process described above and illustrated in the drawings is shown as a sequence of steps, this was done solely for the sake of illustration. Accordingly, it is contemplated that some steps may be added, some steps may be omitted, the order of the steps may be re-arranged, and/or some steps may be performed simultaneously.

Reference List
1 Housing
2 Rotor 1
3 Rotor 2
4 Rotor 3
5 Stator 1
6 Stator 2
7 Stator 3
8 Motor Shaft
9 Casing endcover
10 Wiring Harnes
11 Cooling Fan
12 Controller box
, Claims:We Claim:
1. A magnet-less multi-stage electric motor, wherein the said motor is configured to dynamically adjust the overall power based on the torque demand of the vehicle.
2. A magnet-less multi-stage electric motor, as claimed in claim 1 wherein the dynamically adjust power is achieved by dividing a single rotor and stator in to one or more rotors and stators of varied power output.
3. A magnet-less multi-stage electric motor, as claimed in claim 1 wherein the said torque demand of the vehicle is set by the sensors connected to the controller which analyses the speed and load of the vehicle.
4. A magnet-less multi-stage electric motor, as claimed in claim 1 wherein the said multistage motor comprises of one or more set of rotors and stators which are devoid of magnets.
5. A magnet-less multi-stage electric motor, as claimed in claim 4 wherein one or more set of rotors and stators are activated based on power requirement characterized in that the first rotor -stator operates at the lower power, the second at more power and the third at power more than the second, s the torque demand of the vehicle increases the switching between the rotor-stator combinations happens which is decided by the controller
6. A magnet-less multi-stage electric motor, as claimed in claim 3 wherein the said one or more set of rotors are connected concentrically to the motor centre shaft characterized in that the said one or more set of rotors are placed at a predetermined distance from one another.
7. A magnet-less multi-stage electric motor, as claimed in claim 3 wherein the said one or more set of stators are mounted on the motor outer casing of the said magnet-less multi-stage electric motor.
8. A magnet-less multi-stage electric motor, as claimed in claim 1 wherein one end of the motor shaft is connected with a fan to cool the motor.
9. A magnet-less multi-stage electric motor, as claimed in claim 1 wherein heat generated while operating multi-stage motor is comparatively lower than an equivalent single rotor and stator motor which increases the overall efficiency of the motor.
10. A magnet-less multi-stage electric motor, as claimed in claim 1 wherein the said Magnet-less Multi-stage motor have the highest efficiency due to its working principle that allows only required amount of power to be delivered by switching On and Off the different rotor-stator combinations.

Dated- 26th Day of Nov 2024 Signature of the Agent
Rajat Chaudhary IN/PA-3136