Three-phase wireless power transmission synchronous machine for wireless power transmission

Abstract

A three-phase wireless power transmission synchronous machine (100) for wireless power transmission including: a motor body (101); a three-phase stator (102); an electromagnetic rotor (104) having winding (117); a wireless power transmission (WPT) arrangement having a receiver part (107) and a transmitter part (108). The receiver coil part (107) is electrically coupled with to the electromagnetic rotor (102). The transmitter part (108) is electrically coupled to the motor body (101). An air gap between the receiver part (107) and the transmitter part (108) is filled with ferro-fluid. Moreover, configuration of the rotor (104) is optimized by employing cold rolled grain oriented (CRGO) laminated segmented teeth backed by cold rolled non-grain oriented (CRNGO) or sintered yoke or joined with SMC based adhesive to attain the improvised and focused lines and improves its torque density that leads to efficient the machine (100).

Description

THREE-PHASE WIRELESS POWER TRANSMISSION SYNCHRONOUS MACHINE FOR WIRELESS POWER TRANSMISSIONFIELD OF PRESENT INVENTION:

[0001] The present disclosure belongs to a 3-phase wireless power transmission synchronous machine. More particularly, the present invention is directed at an advancement and improvement in existing prior art 3-phase wireless power transmission synchronous machine, i.e., 3 phase synchronous motor.

[0002] In particular, the present invention pertains to a DC (direct current) excited 3- phase synchronous machine which is configured with wireless power transmission (WPT) to reduce the rotor losses (frictional losses) and improves the efficiency of power transmission and torque density through the focused flux lines, achieves compact design, optimizes the weight and rotor inertia by half shafts in rotors.BACKGROUND OF PRIOR ARTS OF PRESENT INVENTION:

[0003] A three-phase wireless power transmission synchronous machine or a motor is an electrical equipment or an element, which converts electrical energy into mechanical energy, which primarily consists of two major parts, namely a 3-phase stator and an electromagnetic rotor with winding.

[0004] Conventionally, various modes have been employed in the existing conventional synchronous machine or motor in order to transfer power to the rotor (or from the power source to an electric load), for example, battery as a power supply on rotor, slip rings or brushes induction machine on rotor, or WPT (wireless power transmission).

[0005] In existing prior art wireless power transmission (WPT), the transmission of electrical energy takes place, wirelessly without using any wire as a physical link, using an electromagnetic field to efficiently transfer the power. In the wireless power transmission system, an electrically poweredtransmitter device generates a time-varying electromagnetic field that transmits power across space to a receiver device, the receiver device extracts power from the field and supplies it to electrical load. It must be noted that wireless power transfer occurs with high frequency switching at around 100kHz-300kHz. Thus, the wireless power transmission system eliminates the use of wires and batteries, thereby it increases mobility, convenience, and safety of electronic devices for users. In particular, the wireless power transfer is particularly useful to the power electrical devices where interconnecting the wires is inconvenient, hazardous, or not possible.

[0006] In existing conventional three phase wireless power transmission synchronous machine, a receiver side of wireless power transmission is coupled to the rotor and a transmitter part is mounted to the motor body, it includes an air gap between the receiver and the transmitter in wireless power transmission system and the concern in the existing three phase wireless power transmission synchronous machine is that the rotor is a rotating element with a rotary moment and it causes rotor losses (e.g., power loss) during its rotating motion.

[0007] Consequently, it is a desperate need to overcome the rotor losses (e.g., power loss) during rotating motion of the rotor in existing three phase wireless power transmission synchronous machine for wireless power transmission.

[0008] In existing three phase wireless power transmission synchronous machine, the slip rings, or brushes are one of the solutions for this type of power transmission system, however, it periodically causes frictional losses and wearing and therefore requires regular maintenance. In addition, an induction machine on rotor based wireless power transmission is comparatively less efficient and therefore requires starting adjustments. Further, the existing machines with wireless power transmission use very thin air gaps and causes complexity in design, which results in failure under vibrational effects.

[0009] Moreover, the magnet-based motor or induction rotor-based motor isused which is a challenge in supply chain and manufacturing and the battery on rotor requires periodic charging and replacement of the cells, which degrades the performance over a period of time, if not charged or changed regularly.

[0010] Furthermore, the existing three phase wireless power transmission synchronous machine for wireless power transmission employs full-length shaft in rotors which excessively increases the overall weight and rotor inertia during operations. In addition, the existing rotors have cold-rolled non-grain-oriented steel (CRNGO) on stator and rotor that renders an isotropic stator and rotor, therefore streamlined flux lines cannot be achieved.

[0011] Thus, there is a desperate need to develop the three-phase wireless power transmission synchronous machine for wireless power transmission which obviates at least the above-mentioned problems associated with the existing prior arts and particularly addresses the technical problem associated with rotor losses (e.g., power losses) during operations, i.e., rotating motions of the rotor.OBJECT OF THE PRESENT INVENTION:

[0012] The principal object of the present invention is to develop DC excited three phase wireless power transmission synchronous machine for wireless power transmission, which overcomes the problems and drawbacks associated with the existing prior arts.

[0013] Another object of the present invention is to develop DC excited three phase wireless power transmission synchronous machine for wireless power transmission, which reduces the rotor losses (e.g., power losses) during rotating motion, operation.

[0014] Yet another object of the present invention is to develop DC excited three phase wireless power transmission synchronous machine for wireless power transmission, which reduces frictional losses and wearing of power transmitting elements.

[0015] Still another obj ect of the present invention is to develop DC excited three phase wireless power transmission synchronous machine for wireless power transmission, which eliminates the requirements of battery and magnets to overcome the problems associated with supply chain issues.

[0016] Yet, one more object of the present invention is to develop DC excited three phase wireless power transmission synchronous machine for wireless power transmission, which optimizes overall weight and rotor inertia of the system.

[0017] Still, one more object of the present invention is to develop DC excited three phase wireless power transmission synchronous machine for wireless power transmission, which efficiently produces the streamlined flux lines.SUMMARY OF THE INVENTION:

[0018] In one embodiment, a three-phase wireless power transmission synchronous machine for wireless power transmission, includes a motor body; a three-phase stator; an electromagnetic rotor having winding; a wireless power transmission (WPT) arrangement having a receiver part and a transmitter part. The receiver part is electrically coupled with the electromagnetic rotor and the transmitter part is electrically coupled to the motor body. The air gap between the receiver part and the transmitter part is filled with ferro-fluid. The ferro-fluid acts as ferrite beads of wireless power transmission system to improve the efficiency of the wireless power transmission system and to reduce the power losses of the electromagnetic rotor. In one embodiment, the air gap between the receiver part and the transmitter part is in the range of 1mm to 10 mm.

[0019] In one embodiment, the ferro-fluid is made by mixing motor oil, grease any viscous material with viscosity ranging from 50-70,000 Centipoise, with soft magnetic composite (SMC) powder. In one embodiment the Soft MagneticComposite (SMC) powder made up of Fe-Si, Fe-Ni, or Fe-Co for enhanced magnetic properties. Each iron powder particle is coated with a thin layer of electrically insulating material, preventing eddy currents and improving efficiency. In one embodiment, the electromagnetic rotor has grain-oriented GO teeth and non-grain-oriented NGO yoke, the grain-oriented GO teeth is configured to attach on the slots of the electromagnetic rotor which results in streamline of flux flow and avoiding the cogging torque thereof.

[0020] In one embodiment, a gap between the grain-oriented GO teeth and the non-grain-oriented NGO yoke is being filled with the ferro-fluid or SMC mixed with anaerobic adhesive to produce improved flux flow when the electromagnetic rotor attached with the receiver part starts rotating. The wireless power transmission WPT arrangement is configured to transfer the DC power to the electromagnetic rotor through the ferro-fluid which utilizes electromagnetic field to efficiently transfer the DC power. In one embodiment, geometry dimensions of the wireless power transmission WPT arrangement are variable based on the geometry dimensions of the machine.

[0021] In another embodiment, the electromagnetic rotor is designed such that the receiver part of the wireless power transmission WPT arrangement is electrically coupled with the electromagnetic rotor securely. In yet another embodiment, the motor body is designed such that the transmitter part is electrically coupled with the motor body securely. In one embodiment, the ferrofluid also cools the components of the wireless power transmission WPT arrangement and machine.BRIEF DESCRIPTION OF DRAWINGS:

[0022] Figure. 1 depicts a perspective view of a three-phase wireless power transmission synchronous machine in accordance with an embodiment of the present invention;

[0023] Figure. 2 illustrates a cross-sectional view of the three-phase wireless power transmission synchronous machine as shown in accordance with an embodiment of the present invention;

[0024] Figure. 3 shows a perspective view of a rotor with winding having wireless power transmission connection layout in the machine in accordance with an embodiment of the present invention;

[0025] Figure. 4 exhibits a cross-sectional view of the three-phase wireless power transmission synchronous machine in accordance with an embodiment of the present invention;

[0026] Figure. 5 depicts an exploded view of the three-phase wireless power transmission synchronous machine in accordance with an embodiment in the present invention;

[0027] Figure. 6 illustrates a cross-sectional view of the three-phase wireless power transmission synchronous machine in accordance with an embodiment of the present invention;

[0028] Figure. 7 illustrates a rotor assembly, particularly Grain oriented rotor teeth and non-grain-oriented yoke-based rotor in according to an embodiment of the present invention;

[0029] Figure. 8 illustrates a detailed view of a rotor tooth of the rotor in accordance with an embodiment of present invention;

[0030] Figure. 9 illustrates a rotor spoke holder of the rotor in accordance with an embodiment of the present invention;

[0031] Figures 10A-10B illustrates a laminated view of the rotor in accordance with an embodiment of the present invention; and

[0032] Figure. 11 exhibits an assembled view of the wireless power transmission synchronous machine as shown in accordance with the present invention.

[0033] In addition, further aspects and technical advantages / advancement associated with the present invention will become apparent from the ensuing description section of the present invention as below.DESCRIPTION OF THE PRESENT INVENTION:

[0034] The nature of the invention and the manner in which it works is clearly described in the present complete specification. The invention has various embodiments, and they are explicitly described in the following pages of the specification. Before elaborating the present invention, it is to be understood that the phraseology and terminology employed herein is for the purpose of description and not for limitation.

[0035] Before explaining the present invention, it is to be understood that the term “DC” employed in the present specification generally used in an electrical power generation industry and refers to a direct current. Further, the term “three phase synchronous machine” refers a 3-phase synchronous motor which converts 3- phase electricity (electrical energy) input into mechanical energy output.

[0036] The present invention refers to DC excited 3-phase wireless power transmission synchronous machine for wireless power transmission, which substantially reduces rotor losses (e.g., power losses) during operations, i.e., rotating motions of rotor, eliminates the contact between the power transmitting elements and thereby eliminates frictional losses and avoids the requirements of magnets and battery on rotor and thereby eventually improves the overall efficiency and fill factor of the wireless power transmission.

[0037] In accordance with the Figs. 1-4, the DC excited three phase wireless power transmission synchronous machine for wireless power transmissionaccording to the present invention includes a motor body, a 3 -phase stator and an electromagnetic rotor having windings. The important aspect of the present invention is that the wireless power transmission (WPT) has been employed to transfer the DC power to the rotor without using any wires as a physical link and uses an electromagnetic field to efficiently transfer the power. In particular, a receiver side of the wireless power transmission is electrically coupled to the rotor and a transmitter part is electrically coupled to the motor body and the overall setup of this wireless power transmission is disposed in a liquid leak proof container, both the receiver and transmitter elements are submerged in a pool of ferro-fluid. The ferro-fluid is produced by mixing motor-oil and / or veg oil or grease with soft magnetic composite (SMC) powder materials, the SMC powder materials have minimum losses at high frequency.

[0038] In accordance with an embodiment of the present invention, there is an air gap between the receiver and the transmitter in the wireless power transmission system which is filled with the ferro-fluid having an adequate viscosity, the ferro-fluid acts as ferrite beads of wireless power transmission system and improves an efficiency of the wireless power transmission system and reduces the rotor losses (power losses).

[0039] Moreover, the rotor configuration according to the present invention is optimized by employing cold rolled grain oriented (CRGO) laminated segmented teeth backed by cold rolled non grain oriented (CRNGO) or sintered yoke, particularly to attain the improvised and focused flux lines and thereby improved its torque density which leads to an efficient motor. In addition, the arrangement of wireless power transmission system according to the present invention is mounted within the motor, in order to achieve compact design and to utilize the overhang part of coils. Further, the use of half shafts in rotors according to the present invention also optimizes the weight and rotor inertia of the system.

[0040] Now referring to figure. 5 an exploded view of the three-phase wireless power transmission synchronous machine (100) for wireless power transmission,includes a motor body (101), a three-phase stator (102), an electromagnetic rotor (104), and a wireless power transmission (WPT). The electromagnetic rotor (104) has winding (117), the wireless power transmission (WPT) arrangement has a receiver part (107) and a transmitter part (108). In one embodiment, the receiver coil part (107) is electrically coupled with the electromagnetic rotor (102), and the transmitter part (108) is electrically coupled to the motor body ( 101 ) . In another embodiment, an air gap between the receiver part (107) and the transmitter part (108) is fdled with ferro-fluid. In one embodiment, the machine (100) includes a hollow shaft (103). The hollow shaft (103) is rotatably fixed with the electromagnetic rotor (104). In one embodiment, the receiver part (107) is fixed in a receiver holder (106). The air gap between the receiver part (107) and the transmitter part (108) is in the range of 1mm to 10mm.

[0041] In one embodiment, the three-phase wireless power transmission synchronous machine (100) is submerged with the container having ferro-fluid for wireless power transmission.

[0042] Further, the wireless power transmission (WPT) arrangement is assembled in a leak proof chamber (111). In another embodiment, the machine (100) includes O rings to allow a completely sealed assembly of the machine (100) which avoids leakage of ferro-fluid or oil, or grease form the machine (100). The ferro-fluid is filled in the hydraulic chamber (109). Additionally, the machine (100) includes a filter plug (113). The filter plug (113) seals the machine (100) and avoids leakage of oil, grease or ferro fluid from the machine (100). In one embodiment, the machine (100) includes a transmitter holder (114) to assemble the transmitter part (108) in the hydraulic chamber (109). In one embodiment, the machine (100) includes end shields (105, 116) to contain the stator (102) and the rotor (104) assembly in the machine (100). In one embodiment, the machine (100) includes fixing elements (112, 115) to fix the machine assembly. The fixing elements (112, 115) may be, but it is not limited to rivets, studs, screws, or pins.

[0043] In one embodiment, the ferro-fluid acts as ferrite beads of wireless power transmission system to improve the efficiency of the wireless power transmission system and to reduce the power losses of the electromagnetic rotor (104). The ferro-fluid is made by mixing motor oil with soft magnetic composite (SMC) powder. In one embodiment, the ferro-fluid can be made by other suitable materials having better electromagnetic flux. In one embodiment, the ferro-fluid is filled in the airgap between transmitter and receiver coil enhancing better flux transfer. The ferro-fluid is made by mixing motor oil, grease or any viscous material with viscosity ranging from 50-70,000 Centipoise, with soft magnetic composite (SMC) powder. The soft magnetic composite powder is made up of Fe-Si, Fe-Ni, or Fe-Co for enhanced magnetic properties. Each iron powder particle is coated with a thin layer of electrically insulating material for preventing eddy currents and improving efficiency.

[0044] In one embodiment, the electromagnetic rotor (104) has grain oriented (GO) teeth and non-grain oriented (NGO) yoke. The grain-oriented (GO) teeth are configured to attach on the slots of the electromagnetic rotor (104) which results in streamline of flux flow and avoiding the cogging torque and torque ripples thereof. In one embodiment, a gap between the grain oriented (GO) teeth and the non-grain oriented (NGO) yoke is being filled with the ferro-fluid or SMC mixed with anaerobic adhesive to produce improved flux flow when the electromagnetic rotor (104) attached with the receiver coil part (107) starts rotating.

[0045] In another embodiment, the wireless power transmission (WPT) arrangement is configured to transfer the DC power to the electromagnetic rotor (104) through the ferro-fluid which utilizes electromagnetic field to efficiently transfer the DC power. In one embodiment, ferro-fluid is filled in the airgap between transmitter and receiver coil enhancing better flux transfer. In one embodiment, geometry dimensions of the wireless power transmission (WPT) arrangement are variable based on the geometry dimensions of the machine.

[0046] In another embodiment, the electromagnetic rotor (104) is designed such that the receiver coil part (107) of the wireless power transmission (WPT) arrangement is electrically coupled with the electromagnetic rotor (104) securely. The motor body (101) is designed such that the transmitter part (108) is electrically coupled with the motor body (101) securely. In one embodiment, the ferro-fluid also cools the components of the wireless power transmission (WPT) arrangement and machine (100).

[0047] Now referring to figure. 6, a cross-sectional view of the three-phase wireless power transmission synchronous machine (100) is disclosed. The figure. 6 discloses a rotor winding (117) wound around the electromagnetic rotor (104). Further, a stator winding (118) is wound around the stator (102).

[0048] Referring to figure. 7 illustrates a rotor assembly (104) particularly Grain oriented rotor teeth and non-grain-oriented yoke-based rotor in accordance with an embodiment of the present invention. The rotor assembly (104) includes teeth (104a), the rotor spoke holder (104c) and stud holes (104b). in one embodiment, the number of teeth ranges from 4 to 12. The number of teeth is determined by power output required. More the number of teeth smoother the power output.

[0049] Figure. 8 illustrates a detailed view of a rotor tooth (104a) of the rotor (104). The rotortooth (104a) includes a body (104-1) connected to a leg (104-3) via a bridge (104). The body includes holes (104-4) which allow assembly of the studs, rivets, or any fixing elements, so as to laminate multiple teeth to the rotor assembly.

[0050] Figure. 9 illustrates a rotor spoke holder (104c) of the rotor (104). The rotor spoke holder (104c) includes a shaft hole (104-5) to allow assembly of the hollow shaft (103). Further, the rotor spoke holder (104c) a plurality of slots (104-7) to allow assembly of the teeth (104a) with the rotor spoke holder. The rotor spoke holder (104c) includes holes (104-6) which allow assembly of laminations of the rotor (104).

[0051] Figures 10A-10B illustrates assembly of the laminations of the rotor (104). Figure. 10A discloses a side view of how multiple laminations are assembled to form the rotor (104). Further, the figure, 10B discloses an isometric view of the rotor (104) of how the multiple laminations are assembled using fixing elements may be but on not limited to studs, rivets to form a rotor (104). Figure. 11 exhibits an assembled view of the wireless power transmission synchronous machine in accordance with the present invention.

[0052] Test Data:As shown below tables 1-4, the three-phase wireless power transmission synchronous machine (100) has been tested based on various conditions such as with ferro-fluid or without ferro-fluid. As shown in Table no. 3, the machine (100) with ferro-fluid provided approximately 3% improvement in higher voltage. It must be noted that the Pure Air gap means, no material in between Transmitter and Receiver of WPT and the Tuning Parameters are the machine (100) parameters that are used to tune the machine (100) with electronic controller to run the machine (100).

[0053] TECHNICAL ADVANCEMENT / EFFECTS ATTAINED BY PRESENT INVENTION: a. By virtue of the three-phase wireless power transmission synchronous machine for wireless power transmission, it makes possible to reduce rotor losses (e.g., power losses) during rotating motion and operation, while diminishing the frictional losses and wearing of power transmitting elements. b. In addition, the present invention also eliminates the requirement of battery and magnets and thereby it overcomes the problems and drawbacks associated with supply chain issues.c. Moreover, the present invention also optimizes the overall weight and rotor inertia of the three-phase wireless power transmission synchronous machine for wireless power transmission and enables it to efficiently produce the streamlined flux lines. d. The three-phase wireless power transmission synchronous machine as per present invention is a magnet free motor which give similar performance to the products available in the market. e. The three-phase wireless power transmission synchronous machine as per present invention has high slot fill factor in rotor winding therefore has high power density. f. The three-phase wireless power transmission synchronous machine as present invention the rotor made with GO + NGO / Sintering is optimized for streamline flux flow and hence for high torque generation. g. The three-phase wireless power transmission synchronous machine includes GO stator teeth and NGO / Sintered Yoke is joined using Ferrous / SMC Powder and Cyanoacrylate, Resin, or suitable adhesive. h. The three-phase wireless power transmission synchronous machine as per present invention has no dependency on magnet or pressure die cast (PDC). i. The three-phase wireless power transmission synchronous machine is easy to assemble, and more controllability on algorithms. j. The three-phase wireless power transmission synchronous machine the pool concept will play cooling role for the WPT electronics and electrical systems.

[0054] The present invention may have various embodiments with the similarinventive concept that should be construed within the purview of present invention. The terms and phrases used in the present complete specification are solely for the purposes of explanation and elaboration and it should not be construed as limiting the scope of the present invention.

[0055] It will be appreciated that variations of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Also, that various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed. This invention is no way limited to the embodiment described in the drawing sheet.Table 15 Table. 2Table. 3Table. 4LIST OF REFERENCE NUMERALS:100: A three-phase power transmission synchronous machine101: A motor body102: A three-phase stator103: A hollow shaft104: An electromagnetic rotor105: An end-shield106: A receiver holder107: A receiver part108: A transmitter part109: A hydraulic chamber110: O rings112, 115: means for assembly113: A Filter plug114: A transmitter holder116: An end shield117 : A rotor winding118 : A stator windingLIST OF ABBREVIATIONS:WPT: Wireless Power Transfer Ni: NickelGO: Grain Oriented Eff: EfficiencyNGO: Non-Grain OrientedSMC: Soft Magnetic CompositePDC: Pressure Die CastPh: PhaseN-S: North SouthIP: Ingress ProtectionFe: IronSi: SiliconCo: Cobalt

Claims

CLAIMS1. A three-phase wireless power transmission synchronous machine (100) for wireless power transmission, comprising: a motor body (101); a three-phase stator (102); an electromagnetic rotor (104) having winding (117); a wireless power transmission (WPT) arrangement having a receiver part (107) and a transmitter part (108), wherein said receiver coil part (107) is electrically coupled with to said electromagnetic rotor (102), and said transmitter part (108) is electrically coupled to the motor body (101), wherein an air gap between said receiver part (107) and said transmitter part (108) is fdled with ferro-fluid.

2. The wireless power transmission synchronous machine (100) as claimed in claim 1, wherein said ferro-fluid acts as ferrite beads of wireless power transmission system to improve the efficiency of the wireless power transmission system and to reduce the power losses of said electromagnetic rotor (104), wherein said air gap between said receiver part (107) and said transmitter part (108) is in the range of 1 mm to 10 mm.

3. The wireless power transmission synchronous machine (100) as claimed in claim 1, wherein said ferro-fluid is made by mixing motor oil, grease or any viscous material with viscosity ranging from 50-70,000 Centipoise with soft magnetic composite (SMC) powder, wherein said soft magnetic composite powder is made up of Fe-Si, Fe-Ni, or Fe-Co for enhanced magnetic properties, wherein each iron powder particle is coated with a thin layer of electrically insulating material for preventing eddy currents and improving efficiency.

4. The wireless power transmission synchronous machine (100) as claimed in claim 1, wherein said electromagnetic rotor (104) has grain oriented (GO) teeth (104a) and non-grain oriented (NGO) yoke, wherein said grain oriented (GO) teethis configured to attach on the slots of said electromagnetic rotor (104) which results in streamline of flux flow and avoiding the cogging torque thereof.

5. The wireless power transmission synchronous machine (100) as claimed in claim 4, wherein a gap between said grain oriented (GO) teeth (104a) and said nongrain oriented (NGO) yoke is being filled with said ferro-fluid or SMC mixed with anaerobic adhesive to produce improved flux flow when said electromagnetic rotor (104) attached with said receiver coil part (107) starts rotating.

6. The wireless power transmission synchronous machine (100) as claimed in claim 1, wherein said wireless power transmission (WPT) arrangement is configured to transfer the DC power to said electromagnetic rotor (104) through said ferro-fluid which utilizes electromagnetic field to efficiently transfer the DC power.

7. The wireless power transmission synchronous machine (100) as claimed in claim 1, wherein geometry dimensions of said wireless power transmission (WPT) arrangement are variable based on the geometry dimensions of the machine.

8. The wireless power transmission synchronous machine (100) as claimed in claim 1 , wherein said electromagnetic rotor ( 104) is designed such that said receiver coil part (107) of said wireless power transmission (WPT) arrangement is electrically coupled with said electromagnetic rotor (104) securely, wherein said motor body (101) is designed such that said transmitter part (108) is electrically coupled with the motor body (101) securely.

9. The wireless power transmission synchronous machine as claimed in claim 1, wherein said ferro-fluid also cools the components of said wireless power transmission (WPT) arrangement and machine.

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