Rotary transformer suitable for high-rotating-speed working condition of wireless electric energy transmission system

Abstract

The invention discloses a rotary transformer suitable for a high rotating speed working condition of a wireless power transmission system, which comprises a rotor magnetic core and a rotor winding, the rotor magnetic core is provided with n notches, the rotor magnetic core is divided into n unit rotor magnetic core areas, and n is greater than or equal to 3; the number of the rotor windings is at least n, the at least n groups of rotor windings are sequentially rotated and staggered by 360 / n degrees, each group of rotor windings is a full-wave winding formed by two half-wave windings, and the half-wave winding of each rotor winding at least surrounds two unit rotor magnetic core areas and at most surrounds n-1 unit rotor magnetic core areas; each unit rotor magnetic core area is surrounded by at least one rotor winding and at most n rotor windings, the rotary transformer can adjust the turn ratio of the stator to the rotor of the transformer, meanwhile, the size of the rotor magnetic core is considered, and the rotary transformer is suitable for capacity expansion in a high-speed rotation occasion.

Description

Technical Field

[0001] The invention relates to a rotary transformer structure suitable for a wireless power transmission system, belonging to the field of wireless power transmission. Background Art

[0002] Wireless Power Transfer (WPT) technology, due to its contactless nature between the power transmitter and receiver, greatly increases the safety, convenience, and reliability of charging systems. It has high practical value and potential economic benefits in fields such as biomedicine, foreign object detection, underwater power supply, and electric vehicle charging.

[0003] Rare earth permanent magnet motors offer excellent performance and are adopted by the vast majority of passenger car manufacturers. To reduce rare earth metal consumption, the EU's Critical Raw Materials Directive designates rare earth metals as critical raw materials in overseas markets. The rare earth metal industry chain is primarily located in East Asia, leading many companies to seek technological alternatives to reduce their use to comply with regulations. Electromagnetic motors, which inherently contain no rare earth elements and offer superior performance compared to induction motors, are favored in overseas markets. Mechanical slip rings, which achieve energy and information exchange through dynamic contact between brushes and conductive rings, are widely used in generator excitation fields. During rotation, friction between the brushes and conductive rings can lead to wear, sparking, and dust accumulation, reducing the reliability of the slip rings. Furthermore, the slip rings are relatively bulky. To address these issues, future development is moving towards contactless power supply to the rotor excitation winding.

[0004] To meet the growing power demand of electric vehicles, it is necessary to achieve higher energy transmission capabilities with smaller product volume. The common practice in existing technologies is to use multi-module parallel, multi-phase or matrix transformer solutions to evenly distribute the output current. However, multi-channel and multi-phase technologies have the problems of complex structure, large volume and weight. Summary of the Invention

[0005] In order to solve the problems existing in the prior art, the present invention provides a rotary transformer with expanded capacity suitable for high-speed rotation occasions.

[0006] In order to achieve the above-mentioned purpose, the technical solution proposed in the present invention is: a rotating transformer suitable for high-speed working conditions of a wireless power transmission system, comprising a stator part and a rotor part, the rotor part comprising a rotor core and a rotor winding, the rotor core being evenly provided with n slots, dividing the rotor core into n unit rotor core areas, n≥3; the rotor winding is provided with at least n groups, and the at least n groups of rotor windings are rotated and offset by 360 / n degrees in sequence, each group of rotor windings is a full-wave winding composed of two half-wave windings, and the half-wave winding of each rotor winding surrounds at least 2 unit rotor core areas and at most n-1 unit rotor core areas; each unit rotor core area is surrounded by at least 1 rotor winding 2b and at most n rotor windings.

[0007] A further design of the above technical solution is as follows: the stator part includes a stator core, a stator winding and a stator shell; the rotor part also includes a rotating shaft, the rotor core is wrapped around the outside of the rotating shaft, the stator core is wrapped around the outside of the rotor core and the inside of the stator shell, and the stator winding is wrapped around the outside of the rotor core and the inside of the stator core.

[0008] The slots formed on the rotor core are half slots or through slots.

[0009] The half-wave windings of each rotor winding surround the same number of unit rotor core areas.

[0010] The rotary transformer structure further includes a rectifier unit, and the rotor winding is electrically connected to the rectifier unit.

[0011] The stator winding and the rotor winding are made of PCB board, solid conductor, Litz wire or copper foil; the stator shell is made of aluminum alloy, magnesium alloy, PEEK or ceramic.

[0012] A rotary transformer suitable for high-speed operation of a wireless power transmission system comprises a stator portion and a rotor portion, wherein the stator portion comprises a stator core and a stator winding, and the rotor portion comprises a rotor winding, a rotor core, and a rotating shaft. The rotor core is arranged inside the rotating shaft, the stator core is arranged inside the rotor core, and the stator winding is wound around the inside and outside of the rotor core. The stator core is uniformly provided with n slots to divide the stator core into n unit stator core areas, where n is greater than or equal to 3. The rotor winding is provided with at least n groups, and the at least n groups of rotor windings are sequentially rotated and offset by 360 / n degrees. Each group of rotor windings is a full-wave winding composed of two half-wave windings, and the half-wave winding of each rotor winding surrounds at least two unit stator core areas and at most n-1 unit stator core areas. Each unit stator core area is surrounded by at least one rotor winding and at most n rotor windings.

[0013] A further design of the above technical solution is as follows: the stator core is provided with a circumferentially arranged avoidance gap at a position corresponding to the rotor winding.

[0014] A rotary transformer suitable for capacity expansion of a wireless power transmission system comprises a stator portion and a rotor portion, characterized in that: the stator portion comprises an inner stator core, an outer stator core, a stator winding, and a stator housing; the rotor portion comprises a rotor winding and a rotating shaft, the inner stator core surrounds the outer side of the rotating shaft, the stator winding surrounds the inner stator core and the outer stator core, and the outer stator core is located on the inner side of the stator housing; the inner stator core is uniformly provided with n notches to divide the inner stator core into n unit stator core areas, where n is greater than or equal to 3; the rotor winding is provided with at least n groups, and the at least n groups of rotor windings are sequentially rotated and offset by 360 / n degrees, each group of rotor windings is a full-wave winding composed of two half-wave windings, the half-wave winding of each rotor winding surrounds at least two unit stator core areas and at most n-1 unit stator core areas; each unit stator core area is surrounded by at least one rotor winding and at most n rotor windings.

[0015] A further design of the above technical solution is as follows: the inner stator core is provided with a circumferentially arranged avoidance gap at a position corresponding to the rotor winding.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. The rotary transformer of the present invention, which is suitable for high-speed and high-current working conditions of a wireless power transmission system, can adjust the stator-rotor turns ratio of the transformer while taking into account the volume of the rotor core by designing the unit rotor core area or the number of unit stator core areas of a rotorless rotary transformer structure, as well as the number of unit core areas surrounded by each rotor winding. This makes it suitable for capacity expansion in high-speed rotation situations.

[0017] 2. In the rotary transformer of the present invention, there is local coupling between adjacent rotor windings. The forward coupling relationship between adjacent rotor windings under parallel output can ensure the magnetic flux balance of each unit core area, thereby improving the phenomenon of uneven current distribution. No additional control circuits and algorithms need to be added to achieve equal current output of multiple groups of rotor windings.

[0018] 3. In the rotary transformer of the present invention, the fractional turn structure of the rotor winding around multiple unit core areas can reduce the number of turns of the stator winding and the winding path of the rotor winding, thereby reducing the copper loss of the transformer and improving efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is an exploded diagram of the rotary transformer of Example 1; Figure 2This is a schematic structural diagram of the rotor winding of the first PCB board in the rotary transformer of Example 1; Figure 3 This is a schematic structural diagram of the rotor winding of the second PCB board in the rotary transformer of Example 1; Figure 4 This is an exploded diagram of the rotary transformer of Example 2; Figure 5 This is an exploded diagram of the rotary transformer of Example 3; Figure 6 This is a schematic structural diagram of the rotor winding of the first PCB board in the rotary transformer of Example 3; Figure 7 This is a schematic structural diagram of the rotor winding of the second PCB board in the rotary transformer of Example 3; Figure 8 Schematic diagram of the structure of the third rotor winding in the rotary transformer of Example 3; Figure 9 Schematic diagram of another feasible structure of the rotor winding in the rotary transformer of the third embodiment; Figure 10 This is an exploded diagram of the rotary transformer structure of Example 4; Figure 11 This is an exploded view of the rotary transformer structure of the fifth embodiment; Figure 12 This is an exploded view of the rotary transformer structure of Example 6; Figure 13 A schematic diagram of a circuit experimentally verified in a rotary transformer verification embodiment of the present invention; Figure 14 The Maxwell simulation results for the current sharing characteristics verification in the rotary transformer verification example of the present invention are as follows; Figure 15 The Maxwell simulation results for the PEEK material properties verification in the rotary transformer verification example of the present invention; Figure 16 These are efficiency curve results of the circuit applied to the rotary transformer in the rotary transformer verification example of the present invention under different working conditions. DETAILED DESCRIPTION

[0020] The following describes the technical solution of the present invention in detail with reference to the accompanying drawings. It should be noted that, unless there is a conflict, the embodiments of this application and the features within the embodiments may be combined in any manner. Furthermore, the magnetic core of the transformer involved in the embodiments of the present invention may be made of ferromagnetic materials such as silicon steel sheets, ferrites, microcrystals, ultramicrocrystals, Permalloy, or iron-cobalt-vanadium. However, this application does not impose any restrictions on the specific materials used for the transformer. Example 1

[0021] Figure 1The preferred implementation structure of the rotary transformer proposed in this embodiment includes a stator portion and a rotor portion. The stator portion includes a stator core 1a, a stator winding 1b, and a stator housing 1c. The rotor portion includes a rotor core 2a, a rotor winding 2b, a rotating shaft 2c, and a rotating rectifier unit 3 and a connector 3a. The rotor core 2a is arranged around the rotating shaft 2c, the stator core 1a surrounds the outside of the rotor core 2a and the inside of the stator housing 1c, and the stator winding 1b surrounds the outside of the rotor core 2a and the inside of the stator core 1a. The rotor winding 2b and the subsequent rotating rectifier unit 3 are electrically connected via a connector 3a or welding, forming a closed path for the current in the rotor winding.

[0022] The rotor core is evenly provided with n slots, dividing the rotor core into n unit rotor core areas, where n is greater than or equal to 3; the rotor winding is provided with at least n groups, and the at least n groups of rotor windings are sequentially rotated and offset by 360 / n degrees, and each group of rotor windings is a full-wave rotor winding consisting of two half-wave windings, and the half-wave winding of each rotor winding surrounds at least two unit rotor core areas and at most n-1 unit rotor core areas; each unit rotor core area is surrounded by at least one rotor winding 2b and at most n rotor windings.

[0023] Specifically, in this embodiment, the rotor core 2a is evenly provided with four through slots, which divide the rotor core 2a into four unit rotor core areas 2d, each of which is a four-core individual. The corresponding rotor windings 2b are provided with four groups, and the four groups of rotor windings are sequentially rotated and staggered by 90 degrees. The stator winding 1b and the rotor winding 2b are arranged alternately, and the rotor winding 2b uses two rotor PCB boards with the same structure but staggered by 90 degrees along the Z axis, as shown in FIG. Figure 2 、 Figure 3 As shown, each PCB board consists of a top layer and a bottom layer, and each of the top layer and the bottom layer is designed with a set of full-wave rotor windings 2b Atop , 2b Abottom , 2b Btop and 2b Bbottom , the current flowing through it is respectively expressed as i Atop 、 i Abottom 、 i Btop and i BbottomThe two half-wave windings in each full-wave rotor winding 2b correspond to the solid line and the dotted line in the figure. The phase angles of the two groups of full-wave rotor windings 2b on each PCB board differ by 120°. In combination with two rotor PCB boards with the same structure but offset by 90° along the Z axis, the phase angles of the four groups of rotor windings 2b differ by 90° in sequence, that is, they are rotated and offset by 90°. The half-wave winding in each full-wave rotor winding 2b surrounds two unit rotor core areas 2d; each unit rotor core area 2d is surrounded by the half-wave windings of two adjacent rotor windings 2b. The stator housing 1c is made of aluminum alloy.

[0024] Specifically, taking the counterclockwise direction as an example, the full-wave rotor winding 2b Btop 2b ahead Atop 90°; full-wave rotor winding 2b Abottom 2b ahead Btop 90°; full-wave rotor winding 2b Bbottom 2b ahead Abottom 90°; full-wave rotor winding 2b Atop 2b ahead Bbottom 90°, each full-wave rotor winding is coupled with the rotor winding parts that lead and lag itself by 90°, that is, i Atop The rotor winding and i Btop The rotor winding turn chain is a unit rotor core area 2d; i Btop The rotor winding and i Abottom The rotor winding turn chain is a unit rotor core area 2d; i Abottom The rotor winding and i Bbottom The rotor winding turn chain is a unit rotor core area 2d; i Bbottom The rotor winding and i Atop The rotor winding turns chain is a unit rotor core area 2d.

[0025] In the existing common transformer solution, the rotor winding surrounds the entire rotor core. When the stator-rotor turns ratio is 20, the number of rotor turns is N s1 1 turn, four parallel outputs, then the stator winding N p1 20 turns are required, which will result in a larger winding length and loss. There are solutions that can reduce the number of stator winding turns. The rotor core can refer to Figure 1The rotor core is divided into four unit areas. Each rotor core area is wound one turn separately. The four parallel outputs are wound around each of the four rotor core areas with one turn each, which is equivalent to the number of rotor turns around the entire rotor core. N s2 is 1 turn. In this case, the output current is the same as that of the common solution. i s According to formula (1), the stator winding can be calculated N p2 Only 5 turns are needed, which reduces the number of stator winding turns. However, according to formula (2), under the same input voltage, the same switching frequency and the same maximum magnetic flux density, the rotor core area is Ae The expansion to four times the original size has greatly increased the rotor volume, which is unfavorable for rotor stress under high-speed rotation conditions.

[0026] Under this structure of the present embodiment, the number of rotor turns equivalent to the number of turns around the entire rotor core is N s2 The stator winding is 2 turns, and according to formula (1) the stator winding can be calculated as N p2 Only 10 turns are required, and the rotor core area obtained from formula (2) is Ae It is half the size of existing solutions, reducing the number of stator winding turns while ensuring the miniaturization of the rotor core, which is beneficial for high-speed rotation conditions.

[0027] By analyzing the above rotor winding arrangement structure, it can be understood that the adjacent coupled rotor windings are in a forward coupling relationship. In the structure where all rotor winding outputs are connected in parallel, let the output voltage of the rotating rectifier unit 3 be V o , with rotor winding 2b Atop , 2b Abottom and 2b Bbottom Take this as an example for analysis, L Atop 、 L Abottom and L Bbottom is the rotor winding self-inductance, M is the mutual inductance between adjacent rotor windings, then i Atop 、 i Abottom and i Bbottom The following relationship is satisfied:

[0028] When the current is uneven i AtopWhen it increases, due to the positive coupling relationship between the rotor windings, M is positive, at this time i Abottom and i Bbottom Furthermore, since a unit rotor core area 2d is simultaneously i Atop and i Abottom The winding or i Atop and i Abottom The windings are linked at the same time, and when the current of one rotor winding increases, the current of the other rotor winding decreases, so that the changing trends of the magnetic flux flowing through the unit rotor core area 2d offset each other, thereby achieving the current equalization characteristic of the output current of each rotor winding.

[0029] In this embodiment, the rotor core is divided into four areas. The half-wave winding of each full-wave winding surrounds two areas of the turn chain to achieve one output. A rotor full-wave winding is arranged every 90 degrees of rotation, and 4 parallel outputs can be achieved in a circle of 360°. When the rotor core has 6 areas, a rotor winding is arranged every 60 degrees of rotation, and 6 outputs can be arranged in a circle. Similarly, it can be freely set to meet multi-output requirements and achieve capacity expansion.

[0030] Number of turns: In the traditional solution, the rotor winding surrounds all the rotor cores. When the stator-rotor turns ratio of the transformer is 10, the rotor winding has 1 turn and the stator winding has 10 turns. In this embodiment, each rotor winding only wraps around half of the rotor core. For every 1 turn of the rotor winding, the stator winding only needs 5 turns, thus reducing the number of turns. Example 2

[0031] Figure 4 This embodiment proposes another implementation of a rotary transformer. This differs from the first embodiment in that the rotor core 2a has one through-slot and three half-slots, dividing the rotor core 2a into four unit rotor core regions 2d. The rotor core remains a single, integrated core. The rotary transformer structure comprises a stator portion, comprising a stator core 1a, stator windings 1b, and a stator housing 1c. The rotor portion comprises a rotor core 2a, rotor windings 2b, a rotating shaft 2c, a rotating rectifier unit 3, and a connector 3a. Among them, the rotor core 2a is arranged around the rotating shaft 2c; the stator winding 1b and the rotor winding 2b are arranged alternately, using two rotor PCB boards with the same structure but offset by 90° along the Z axis. The half-wave winding in each full-wave rotor winding 2b surrounds two unit rotor core areas 2d; each unit rotor core area 2d is surrounded by the half-wave windings of two adjacent rotor windings 2b, and the number of unit rotor core areas 2d surrounded by each rotor winding 2b is the same. Example 3

[0032] Figure 5 This is another implementation structure of the rotary transformer proposed in this embodiment. The difference from the first embodiment is that the rotor core 2a has 6 slots to divide the rotor core 2a into 6 unit rotor core areas 2d. Figure 1 The figure shows a stator and rotor. The stator consists of a stator core 1a, stator winding 1b, and stator housing 1c. The rotor consists of a rotor core 2a, rotor winding 2b, and a rotating shaft 2c. It also includes a rotating rectifier unit 3 and a connector 3a. The rotor core 2a is arranged around the rotating shaft 2c. The stator winding 1b and rotor winding 2b are wound alternately, using three rotor PCBs with the same structure but offset by 120° along the Z axis. Figure 6 、 Figure 7 、 Figure 8 As shown, each PCB board consists of a top layer and a bottom layer, and each of the top layer and the bottom layer is designed with a set of full-wave rotor windings 2b Atop , 2b Abottom , 2b Btop , 2b Bbottom , 2b Ctop and 2b Cbottom , the current flowing through it is respectively expressed as i Atop 、 i Abottom 、 i Btop 、 i Bbottom 、 i Ctop and i Cbottom It indicates that the two sets of full-wave rotor windings 2b on each PCB board have a phase angle difference of 120°. Combined with three rotor PCB boards offset by 120°, six sets of rotor windings 2b with phase angles of 60° are formed. The half-wave winding in each full-wave rotor winding 2b surrounds three unit rotor core areas 2d. The stator housing 1c is made of aluminum alloy.

[0033] In order to ensure that the magnetic flux on each unit rotor core area 2d is the same, the rotor PCB board can also be staggered 60° along the Z axis, using the following method: Figure 9In the rotor PCB structure shown, each PCB is equipped with three groups of full-wave rotor windings 2b. The phase angle between each two adjacent full-wave rotor windings 2b differs by 120°. In combination with six rotor PCBs with the same structure but offset by 60° along the Z axis, the phase angles of all rotor windings 2b successively differ by 60°, that is, they are rotated and offset by 60°. The half-wave winding in each full-wave rotor winding 2b surrounds two unit rotor core areas 2d; each unit rotor core area 2d is surrounded by the half-wave windings of six adjacent rotor windings 2b, realizing 18 output channels. This solution can be expanded to at least n output channels depending on the number of unit rotor core areas 2d. Example 4

[0034] Figure 10 This is another implementation of the rotary transformer proposed in this embodiment. The rotary transformer structure includes a stator portion and a rotor portion. The stator portion includes a stator core 1a and a stator winding 1b; the rotor portion includes a rotor core 2a, a rotor winding 2b, and a rotating shaft 2c, and also includes a rotating rectifier unit 3. The difference from the first embodiment is that it adopts an outer rotor structure. The rotor core 2a is arranged inside the rotating shaft 2c, and the stator core 1a is arranged inside the rotor core 2a to close the magnetic circuit. The stator winding 1b surrounds the inside of the rotor core 2a and the outside of the stator core 1a to realize a closed current path. The stator core 1a has four slots, which divide the stator core 1a into four unit stator core areas 1d. The stator winding 1b and rotor winding 2b are arranged separately as a single unit, using two identical rotor PCBs offset 90° along the Z axis. The half-wave windings in each full-wave rotor winding 2b surround two unit stator core regions 1d; each unit stator core region 1d is surrounded by the half-wave windings of two adjacent rotor windings 2b. To prevent interference between the rotor winding 2b and the stator core 1a during operation, the stator core 1a is provided with circumferential clearance notches corresponding to the rotor windings. The rotor winding rotates within these clearance notches. Example 5

[0035] Figure 11This is another implementation structure of the rotary transformer proposed in this embodiment. The rotary transformer structure includes a stator portion and a rotor portion. The stator portion includes a stator core 1a, a stator winding 1b, and a stator housing 1c. The rotor portion includes a rotor winding 2b and a rotating shaft 2c. It also includes a rotating rectifier unit 3. The stator core 1a includes an inner stator core and an outer stator core. The difference from the first embodiment is that a rotor-core-free structure is adopted. The inner stator core 1a is arranged around the rotating shaft 2c, and the stator winding 1b is wrapped between the inner stator core and the outer stator core. The inner stator core 1a has four slots that divide the inner stator core 1a into four unit stator core areas 1d. The stator winding 1b and rotor winding 2b are arranged alternately, using two identical rotor PCBs offset 90° along the Z axis. The half-wave windings in each full-wave rotor winding 2b surround two unit stator core sections 2d; each unit stator core section 2d is surrounded by the half-wave windings of two adjacent rotor windings 2b. The stator housing 1c is constructed of aluminum alloy. Similarly, to prevent interference between the rotor winding 2b and the stator core 1a during operation, the stator core 1a is provided with circumferential clearance notches corresponding to the rotor windings. The rotor winding rotates within these clearance notches. Example 6

[0036] Figure 12 This is another implementation of the rotary transformer proposed in this embodiment. The rotary transformer structure includes a stator portion and a rotor portion. The stator portion includes a stator core 1a, a stator winding 1b, and a stator housing 1c; the rotor portion includes a rotor core 2a, a rotor winding 2b, a rotating shaft 2c, and also includes a rotating rectifier unit 3 and a connector 3a. The difference from the first embodiment is that the stator housing 1c is made of PEEK material to reduce eddy current losses. In this embodiment, the stator housing 1c can also be made of metal materials such as magnesium alloy, special engineering plastics, ceramics, etc., and the stator winding 1b, rotor winding 2b, and connector 3a can also be made of solid wire, Litz wire, copper foil, etc. Verification Example

[0037] This verification example adopts the embodiment 1 Figure 1 The rotary transformer structure shown in the figure is verified by Maxwell finite element simulation to verify the current sharing characteristics of the invented structure and the effect of PEEK material on efficiency optimization, and Figure 13 The circuit structure shown is experimentally verified.

[0038] L m —The stator-side magnetizing inductance of the rotary transformer, L r —Resonant inductance of the rotating transformer stator side, C r —Resolution transformer stator side resonant capacitor, k—The coupling coefficient between the stator and rotor windings of the transformer. The circuit parameters are: the inverter circuit input voltage range is 480-600V, the output voltage is 28V, the rated output power is 3kW, the stator and rotor winding turns ratio of the rotary transformer is 20:1:1, and the switching frequency is 200kHz. L m = 121.09μH, L r = 35.2μH, C r = 18nF, controllable switch tube of the inverter circuit in the experiment Q 1. Q 2. Q 3. Q The model of 4 is NTHL020N090SC, the inverter bridge switching frequency is 200kHz; the rectifier circuit synchronous rectifier tube SR 1a 、 SR 1b 、 SR 2a 、 SR 2b 、 SR 3a 、 SR 3b 、 SR 4a 、 SR 4b The model number is IRFS4310ZPbF.

[0039] Maxwell simulation results are as follows Figure 14 As shown, the left figure shows that the magnetic flux on the stator and rotor cores of the rotary transformer is uniformly distributed as a whole, and the right figure shows that the current on each rotor winding is uniformly distributed; therefore, under the rated output working condition, the magnetic flux distribution of the rotary transformer is generally uniform, the magnetic flux coupling is balanced, and the current density distribution on each phase output connector is uniform, which verifies the good current sharing characteristics of the rotary transformer structure of the present invention.

[0040] To verify the effectiveness of using PEEK material to reduce eddy current losses, a comparison was conducted with a metal housing solution. Evaluation metrics included the stator and rotor winding's parasitic resistance, inductance, and coupling coefficient. To simplify the simulation model, the turns ratio was set to 10:1, the rotor used Litz wire instead of the PCB planar winding, the number of turns was set to one, and the stator housing thickness was set to 5mm. The simulation parameter results are shown in Table 1. L p — stator winding self-inductance, L s — rotor winding self-inductance, M — Mutual inductance of stator and rotor windings,R p — stator winding parasitic resistance, R s —Parasitic resistance of rotor winding.

[0041] Table 1: plan <![CDATA[ L p / uH]]> <![CDATA[ L s / uH]]> / uH <![CDATA[ R p / mΩ]]> <![CDATA[ R s / mΩ]]> Metal casing 149.74 1.52 14.99 415.13 4.79 PEEK 159.52 1.62 15.98 207.48 2.77 According to Figure 15 The electrical density simulation results show that PEEK material demonstrates significant advantages in reducing eddy current losses. Metal housings have a significant electrical density center near the air gap, resulting in significant eddy current losses. In contrast, PEEK material exhibits excellent non-magnetic properties. Furthermore, the PEEK solution outperforms the metal housing solution in electrical performance parameters such as inductance, coupling coefficient, and parasitic resistance.

[0042] Figure 16 Efficiency curves are presented for the circuit used in the rotary transformer of the present invention, showing how converter efficiency varies with load current under different input voltages. The output voltage is constant at 28V, and the input voltages are 480V, 540V, and 600V, respectively. Peak efficiency reached 97.12% at an input voltage of 540V and an output current of 80A, and the operating efficiency reached 96.6% at a full load of 120A. These experimental results demonstrate that the rotary transformer structure of the present invention can expand transformer capacity, is suitable for high-current output conditions, and exhibits high energy transfer efficiency.

[0043] Those skilled in the art will appreciate that all or part of the steps in the above method can be performed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium, such as a read-only memory, a magnetic disk, or an optical disk. Alternatively, all or part of the steps in the above embodiment can also be implemented using one or more integrated circuits. Accordingly, each module / unit in the above embodiment can be implemented in the form of hardware or in the form of software functional modules. This application is not limited to any specific form of combination of hardware and software.

[0044] The above-described design examples of the rotary transformer are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of protection of the present invention.

Claims

1. A rotary transformer suitable for high-speed operation of a wireless power transmission system, comprising a stator and a rotor, characterized in that: The rotor part includes a rotor core and a rotor winding. The rotor core is evenly provided with n slots, which divide the rotor core into n unit rotor core areas, where n≥3. The rotor winding is provided with at least n groups, and the at least n groups of rotor windings are rotated and offset by 360 / n degrees in sequence. Each group of rotor windings is a full-wave winding composed of two half-wave windings. The half-wave winding of each rotor winding surrounds at least two unit rotor core areas and at most n-1 unit rotor core areas. Each unit rotor core area is surrounded by at least one rotor winding and at most n rotor windings.

2. The rotary transformer suitable for high-speed operation of a wireless power transmission system according to claim 1, characterized in that: The stator part includes a stator core, a stator winding and a stator shell; the rotor part also includes a rotating shaft, the rotor core is wrapped around the outside of the rotating shaft, the stator core is wrapped around the outside of the rotor core and the inside of the stator shell, and the stator winding is wrapped around the outside of the rotor core and the inside of the stator core.

3. The rotary transformer suitable for high-speed operation of a wireless power transmission system according to claim 2, characterized in that: The slots formed on the rotor core are half slots or through slots.

4. The rotary transformer suitable for high-speed operation of a wireless power transmission system according to any one of claim 3, characterized in that: The half-wave windings of each rotor winding surround the same number of unit rotor core areas.

5. The rotary transformer suitable for high-speed operation of a wireless power transmission system according to any one of claims 2 to 4, characterized in that: It also includes a rectifier unit, and the rotor winding is electrically connected to the rectifier unit.

6. The rotary transformer suitable for high-speed operation of a wireless power transmission system according to claim 5, characterized in that: The stator winding and the rotor winding are made of PCB board, solid conductor, Litz wire or copper foil; the stator shell is made of aluminum alloy, magnesium alloy, PEEK or ceramic.

7. A rotary transformer suitable for high-speed operation of a wireless power transmission system, comprising a stator and a rotor, characterized in that: The stator part includes a stator core and a stator winding, and the rotor part includes a rotor winding, a rotor core and a rotating shaft. The rotor core is arranged on the inner side of the rotating shaft, the stator core is arranged on the inner side of the rotor core, and the stator winding is wound around the inner side of the rotor core and the outer side of the stator core; the stator core is evenly opened with n slots to divide the stator core into n unit stator core areas, n≥3; the rotor winding is provided with at least n groups, and the at least n groups of rotor windings are rotated and offset by 360 / n degrees in sequence, each group of rotor windings is a full-wave winding composed of two half-wave windings, and the half-wave winding of each rotor winding is surrounded by at least 2 unit stator core areas and at most n-1 unit stator core areas; each unit stator core area is surrounded by at least 1 rotor winding and at most n rotor windings.

8. The rotary transformer suitable for high-speed operation of a wireless power transmission system according to claim 7, characterized in that: The stator core is provided with a circumferentially arranged avoidance gap at a position corresponding to the rotor winding.

9. A rotary transformer suitable for capacity expansion of a wireless power transmission system, comprising a stator portion and a rotor portion, characterized in that: The stator part includes an inner stator core, an outer stator core, a stator winding and a stator shell, and the rotor part includes a rotor winding and a rotating shaft. The inner stator core is surrounded by the outer side of the rotating shaft, the stator winding is surrounded by the inner stator core and the outer stator core, and the outer stator core is located on the inner side of the stator shell; the inner stator core is evenly opened with n slots to divide the inner stator core into n unit stator core areas, n ≥ 3; the rotor winding is provided with at least n groups, and at least n groups of rotor windings are rotated and offset by 360 / n degrees in sequence. Each group of rotor windings is a full-wave winding composed of two half-wave windings, and the half-wave winding of each rotor winding surrounds at least 2 unit stator core areas and at most n-1 unit stator core areas; each unit stator core area is surrounded by at least 1 rotor winding and at most n rotor windings.

10. The rotary transformer suitable for high-speed operation of a wireless power transmission system according to claim 9, characterized in that: The inner stator core is provided with a circumferentially arranged avoidance gap at a position corresponding to the rotor winding.

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