A magnetic flux conversion high-frequency rotating loose coupling transformer

Abstract

The application discloses a magnetic flux conversion type high-frequency rotating loose coupling transformer and belongs to the wireless power transmission field. Specifically, the application comprises a rotating assembly and a fixed assembly which constitute a rotating transformer; the rotating assembly comprises a rotor iron core, a rotor winding and a rotor side circuit; the rotor iron core is substantially in the shape of a Chinese character 'Gong', two sides of which are in the shape of a circular arc, and the rotor winding is wound around a middle recess; the fixed assembly comprises a stator iron core, a stator winding and a stator side circuit; the fixed assembly is coaxially arranged on the outer periphery of the rotating assembly, and an air gap with a fixed distance is arranged between the rotating assembly and the fixed assembly; the stator iron core is provided with 12 stator teeth, every two stator teeth form a pair, and the stator winding is arranged in series on each pair of stator teeth. The application adopts a motor type transformer structure and adopts a magnetic conductive material lamination, thereby reducing the requirement of the high-frequency rotating loose coupling transformer on the manufacturing process, improving the power of the rotating transformer, and enabling the application of the rotating transformer to a wireless power supply system of a rotating device, so that the safety and maintenance problems caused by a traditional brush are solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of wireless power transmission, in particular to a magnetic flux conversion type high-frequency rotating loosely coupled transformer. BACKGROUND

[0002] Wireless power transmission technology realizes a new type of power transmission through electromagnetic effect or energy exchange. Rotating loosely coupled transformer, as a key part of this technology, is widely used in the power supply of rotating equipment. Compared with the traditional wired power transmission method, it can effectively prevent safety accidents caused by the aging of the contact slip ring and electric sparks, and is more safe and reliable.

[0003] The existing rotating loosely coupled transformer is mainly of the magnetic tank type, made of ferrite, simple structure, small size, but low power density. The patent number 202120511722.9 has a new design of the magnetic core structure, the stator and rotor are coaxial and located in the same plane, although miniaturized, but only suitable for medium frequency low speed environment, and the power density is not improved. The patent number 202010844240.5 designs a coaxial nested type rotating transformer, which adopts staggered winding to reduce leakage inductance, and the rotor part has no core, thereby reducing the iron loss, and the power density and transmission efficiency are improved, but the structure is complex and the manufacturing process is difficult, and the axial deviation is easy to occur, causing safety hazards.

[0004] Therefore, it is particularly important to develop a wireless power supply loosely coupled transformer which is easy to manufacture, small in size and high in power density.

[0005] The present application combines the principles of electromagnetism, power electronics and wireless energy transmission, and proposes a high-power energy transmission device for energy transmission between fixed and rotating parts, and can realize simple manufacturing and maintenance. SUMMARY

[0006] The technical problem to be solved by the present application is to solve the above-mentioned deficiencies of the prior art, and to provide a magnetic flux conversion type high-frequency rotating loosely coupled transformer. The magnetic flux conversion type high-frequency rotating loosely coupled transformer uses silicon steel sheet instead of ferrite, which effectively improves the structural strength and power density. The motor structure is adopted, which is small in size, easy to manufacture, safe and reliable.

[0007] The technical scheme adopted by the present application is:

[0008] A magnetic flux conversion type high-frequency rotating loosely coupled transformer, comprising a fixed assembly and a rotating assembly.

[0009] The rotating assembly comprises a rotor core (11), a rotor winding (12) and a rotor side circuit (1);

[0010] The rotor core (11) has a cross-section roughly in the shape of an "I" with rounded sides and a recessed middle section where the rotor winding (12) is wound and connected to the rotor side circuit (1).

[0011] The fixed components include a stator core (21), stator windings (AA'~FF'), and stator side circuits (2);

[0012] The fixed component is coaxially mounted on the outer periphery of the rotating component, and a radial air gap with a fixed distance d is provided between the two;

[0013] The cross section of the stator core (21) is similar to that of the stator core of the motor, and is in the shape of a ring. Twelve stator teeth are evenly distributed on the inner circle of the ring along the circumference. Every two stator teeth form a pair. The two stator windings wound on each pair of stator teeth are connected in series and the magnetic flux generated is in the same direction. There are a total of 6 pairs of stator windings. They are connected to the control circuit to control the conduction of the windings on each pair of stator teeth. The control circuit is then connected to other stator side circuits (2).

[0014] The stator side circuit (2) consists of a parallel filter capacitor C1, an inverter full bridge H2, a series resonant capacitor C3, and a control circuit.

[0015] The rotor-side circuit (1) consists of a series resonant capacitor C4, a rectifier full-bridge H1, and a filter capacitor C2.

[0016] The inverter full-bridge H2, resonant capacitor C3, resonant inductor Lk2, resonant capacitor C4, resonant inductor Lk1, rectifier full-bridge H1, and high-frequency rotating loosely coupled transformer windings together form a CLLC resonant circuit.

[0017] The control circuit of the stator side circuit (2) has two connection methods: control circuit E1 or control circuit E2.

[0018] The control circuit E1 consists of 12 auxiliary switches SP1~SP6, SN1~SN6 and 6 pairs of stator winding inductors AA'~FF';

[0019] The control circuit E1 has a total of 6 parallel branches. Each parallel branch consists of an auxiliary switch SP connected in series with a pair of stator winding inductors, and then connected in series with an auxiliary switch SN. The control circuit with six parallel branches consists of a resonant capacitor C3 and a resonant inductor Lk2 connected in series, and connected to the inverter full bridge H2 and the filter capacitor C1 to form the stator side circuit (2).

[0020] Alternatively, the control circuit E2 consists of 12 auxiliary switches SP1~SP6, SN1~SN6 and 6 pairs of stator windings AA'~FF'.

[0021] In the control circuit E2, one end of each pair of stator windings is connected to a point, and the other end of each pair of stator windings is connected to two parallel auxiliary switches SP and SN, and the two parallel branches are connected in series with a resonant capacitor C3 and a resonant inductor Lk2, which are connected to the two ports of the inverter full-bridge H2, and finally connected to the DC power supply through a filter capacitor C2, to form a stator side circuit (2).

[0022] In the control circuit E1 and E2, the connection mode of the resonant capacitor C3 and C4 can also be connected only to the stator side series resonant capacitor C3, and no resonant capacitor on the rotor side.

[0023] Or the resonant capacitor C3 and the resonant capacitor C4 are connected in parallel on the stator and rotor sides respectively.

[0024] Or only connect the stator side parallel resonant capacitor C3, and no resonant capacitor on the rotor side.

[0025] The rotor core (11) and the stator core (21) are preferably made of ultra-thin silicon steel sheets, nanocrystals and the like, and the windings are preferably made of Litz wire, copper wire and the like.

[0026] The present application has the following beneficial effects:

[0027] 1. The motor structure made of silicon steel laminations improves the mechanical strength of the rotary transformer, and the silicon steel sheets are easy to process, reducing the difficulty of the manufacturing process.

[0028] 2. Compared with ferrite, amorphous alloy and other magnetic materials, the silicon steel sheet has increased saturation magnetic density, improved device power density, realized device miniaturization, and can be better applied to the wireless power supply system of the rotating device.

[0029] 3. The present application can be used for rotor electric energy transmission of motor equipment, instead of traditional brush and slip ring system, solving the maintenance and safety problems caused by traditional brush, and improving the safety and reliability of motor operation. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 A structure diagram of a magnetic flux conversion type high-frequency rotating loose coupling transformer according to the present application in Example 1 is shown.

[0031] Figure 2 A structure diagram of a magnetic flux conversion type high-frequency rotating loose coupling transformer according to the present application in Example 2 is shown.

[0032] Figure 3 A circuit connection diagram of a magnetic flux conversion type high-frequency rotating loose coupling transformer according to the present application using control circuit E1 and series-series compensation is shown.

[0033] Figure 4The circuit connection diagram of the magnetic flux conversion type high frequency rotating loosely coupled transformer of the present application is shown, which adopts control circuit E1 and single side series compensation.

[0034] Figure 5 The circuit connection diagram of the magnetic flux conversion type high frequency rotating loosely coupled transformer of the present application is shown, which adopts control circuit E1 and parallel parallel compensation.

[0035] Figure 6 The circuit connection diagram of the magnetic flux conversion type high frequency rotating loosely coupled transformer of the present application is shown, which adopts control circuit E1 and single side parallel compensation.

[0036] Figure 7 The circuit connection diagram of the magnetic flux conversion type high frequency rotating loosely coupled transformer of the present application is shown, which adopts control circuit E2.

[0037] Among them:

[0038] 1. Rotor side circuit;

[0039] 11. Rotor core; 12-16. Rotor winding;

[0040] 2. Stator side circuit;

[0041] 21. Stator core; A-F and A'-F'. Stator winding;

[0042] 3. Magnetic flux path

[0043] H1. Rectifier full bridge; H2. Inverter full bridge;

[0044] T. High frequency rotating loosely coupled transformer;

[0045] E1, E2. Control circuit;

[0046] C1-C2. Filter and voltage stabilizing capacitor; C3-C4. Resonant capacitor; Lk1-Lk2. Resonant inductor;

[0047] S1-S4. Four switches constituting the inverter full bridge; S5-S8. Four switches constituting the rectifier full bridge; SP1-SP6 and SN1-SN6. Control circuit auxiliary switch DETAILED DESCRIPTION

[0048] The present application will be further described in detail below in combination with the drawings and specific preferred embodiments.

[0049] In the description of this invention, it should be understood that the terms "left side," "right side," "upper part," "lower part," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. "First," "second," etc., do not indicate the importance of the components, and therefore should not be construed as a limitation of this invention. The specific dimensions used in this embodiment are only for illustrating the technical solution and do not limit the scope of protection of this invention.

[0050] Example 1

[0051] A flux-conversion type high-frequency rotating loosely coupled transformer has a rotating component fixed on a rotating device and rotating synchronously with the rotating device. The rotating component includes a rotor core (11), a rotor winding (12), and a rotor-side circuit (1).

[0052] The rotor core cross section is roughly "I" shaped with rounded sides. The rotor winding (12) is wound around the middle recessed area and connected to the rotor side circuit (1).

[0053] The fixed components include the stator core (21), the stator windings (AA'~FF'), and the stator side circuit (2).

[0054] The fixed component is preferably secured by an external bracket. The fixed component is coaxially mounted on the outer periphery of the rotating component, with a fixed radial air gap d between them. There is no physical contact between the fixed component and the rotating component, and the fixed radial air gap d is maintained, through which electromagnetic coupling occurs.

[0055] The cross section of the stator core (21) is similar to that of the stator core of the motor, and is in the shape of a ring. Twelve stator teeth are evenly distributed on the inner circle of the ring along the circumference. Every two stator teeth form a pair. The two stator windings wound on each pair of stator teeth are connected in series and the magnetic flux generated is in the same direction. There are a total of 6 pairs of stator windings. They are connected to the control circuit to control the conduction of the windings on each pair of stator teeth. The control circuit is then connected to other stator side circuits (2).

[0056] The stator core (21) and rotor core (11) are preferably made of ultra-thin silicon steel sheets; the rotor winding (12) and stator winding (AA'~FF') are preferably made of copper wire with high magnetic permeability or Litz wire with better performance.

[0057] The size of the rotor core (11) arc in the application ensures that three pairs of stator teeth are completely adjacent to the rotor core (11) during the rotation of the motor, so that the magnetic circuit coupling is facilitated as much as possible, and the core material is fully utilized; during the rotation, the real-time position information of the rotor core (11) is obtained through the position sensor, so that the stator windings on the three pairs of stator teeth completely adjacent to the rotor core (11) arc part at the current time are conducted through the auxiliary switch in the control circuit E, and the auxiliary switches at both ends of the remaining stator windings are turned off, forming a magnetic circuit to transmit electric energy.

[0058] Circuit structure

[0059] A magnetic flux conversion type high-frequency rotating loose coupling transformer, comprising a stator side circuit (2) and a rotor side circuit (1).

[0060] The stator side circuit (2) is composed of a parallel filter capacitor C1, an inverter full bridge H2, a series resonant capacitor C3 and a control circuit E1.

[0061] The rotor side circuit (1) is composed of a series resonant capacitor C4, a rectifier full bridge H1 and a filter capacitor C2.

[0062] The inverter full bridge H2, the resonant capacitor C3, the resonant inductor Lk2, the resonant capacitor C4, the resonant inductor Lk1, the rectifier full bridge H1 and the high-frequency rotating loose coupling transformer winding together constitute a CLLC resonant circuit.

[0063] The control circuit E1 is composed of 12 auxiliary switches SP1-SP6, SN1-SN6 and 6 pairs of stator winding inductances AA'-FF'.

[0064] The control circuit E1 has 6 parallel branches, each parallel branch is composed of an auxiliary switch SP in series with a pair of stator winding inductances, and then an auxiliary switch SN is connected in series; the control circuit composed of six branches is connected in parallel with the resonant capacitor C3 and the resonant inductor Lk2, connecting the inverter full bridge H2 and the filter capacitor C1, to form the stator side circuit (2).

[0065] In actual use, assuming that the rotor core (11) is at the position shown in the figure, the stator windings AA', BB' and CC' need to be turned on, then the position of the rotor core (11) is obtained through the position sensor, and the corresponding auxiliary switches SP1-SP3 and SN1-SN3 are closed, and the remaining auxiliary switches are opened. Figure 1 The position of the rotor core (11) is obtained through the position sensor, and the corresponding auxiliary switches SP1-SP3 and SN1-SN3 are closed, and the remaining auxiliary switches are opened.

[0066] The stator side circuit (2) loop: the DC power supply is converted into an AC power supply through the inverter full bridge H2, and then passes through the resonant capacitor C3 and the resonant inductor Lk2 to connect the control circuit and the high-frequency transformer.

[0067] Rotor-side circuit (1) loop: The high-frequency transformer outputs AC power, which is converted into DC power by the resonant capacitor C4 and the resonant inductor Lk1, and then rectified by the full bridge H1 and delivered to the load; or, as needed, AC power can be delivered to the load by connecting the inverter full bridge.

[0068] In practical applications, the inductance values ​​of both the stator winding and the rotor winding (12) of the transformer in this invention can be used as resonant inductors to participate in resonance.

[0069] Furthermore, the resonant capacitors C3 and C4 can also be connected in a way that only the stator side resonant capacitor C3 is connected in series, with no resonant capacitor on the rotor side.

[0070] Resonant capacitors C3 and C4 can be connected in parallel on the stator and rotor sides, respectively.

[0071] Only the stator side can be connected with a parallel resonant capacitor C3, and there is no resonant capacitor on the rotor side.

[0072] In practical applications, control circuit E2 can be used instead of control circuit E1.

[0073] The control circuit E2 consists of 12 auxiliary switches SP1~SP6, SN1~SN6 and 6 pairs of stator windings AA'~FF';

[0074] In the control circuit E2, one end of each pair of stator windings is connected to a point, and the other end of each pair of stator windings is connected to two parallel auxiliary switches SP and SN. The two parallel branches are then connected in series with resonant capacitor C3 and resonant inductor Lk2 and connected to the two ports of inverter full bridge H2 respectively. Finally, they are connected to the DC power supply through filter capacitor C2 to form the stator side circuit (2).

[0075] In actual use, control circuit E2 assumes that the rotor core (11) is in Figure 1 At the indicated positions, stator windings AA', BB', and CC' need to be turned on. In this case, the corresponding auxiliary switches SP1 and SN2-SN3 are closed, while the remaining auxiliary switches are open. The circuit is as follows: AC power flowing from the inverter bridge passes through resonant capacitor C3, auxiliary switch SP1, stator winding AA', then through stator winding BB', auxiliary switch SN2, and resonant inductor Lk2, returning to the inverter bridge to form a circuit; or it flows through stator winding AA', through stator winding CC', auxiliary switch SN3, and resonant inductor Lk2, returning to the inverter bridge. The switching status of the control circuit at other times during rotation follows the same pattern. The stator and rotor side circuits are the same as when using control circuit E1.

[0076] Example 2

[0077] The difference from Embodiment 1 is the shape of the rotor core (11). In this Embodiment 2, the rotor core (11) is changed to a vertical intersection of two rotor cores (11) in Embodiment 1. The rotor core (11) becomes a 4-pole rotor, and the rotor windings (13, 14, 15, 16) are changed from one to four, respectively wound on the four pillars of the "+" area in the middle of the rotor core (11) and connected in series. Compared with Embodiment 1, an additional magnetic flux path is added.

[0078] Circuit structure

[0079] Figures 3 to 7 The circuit can still be used in the loosely coupled transformer structure of Example 2.

[0080] The difference lies in the switching state of the control circuit.

[0081] Assuming in Figure 2 The rotor core (11) shown is in position, and the stator windings AA', BB', DD', and EE' need to be turned on. When the control circuit E1 is used, the auxiliary switches SP1~SP2, SP4~SP5 and SN1~SN2, SN4~SN5 are closed, and the other auxiliary switches are turned off.

[0082] When using control circuit E2, auxiliary switches SP1, SN2, SN4, and SN5 are closed, and the remaining auxiliary switches are open; the control circuit switches for the other rotor cores (11) during rotation are similarly configured.

[0083] The rotor core (11) can be expanded to more poles, and the stator windings (AA'~FF') and stator side circuits (2) can also be expanded to multiple sets.

[0084] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various equivalent transformations can be made to the technical solutions of the present invention, and these equivalent transformations all fall within the protection scope of the present invention.

Claims

1. A flux-conversion type high-frequency rotating loosely coupled transformer: comprising a fixed component and a rotating component, characterized in that: The rotating assembly includes a rotor core (11), a rotor winding (12), and a rotor-side circuit (1); The rotor core (11) is in the shape of an "I" on the cross section perpendicular to the axial direction, with arcs on both sides and a rotor winding (12) wound in the middle recessed part, which is connected to the rotor side circuit (1). The fixed components include the stator core (21), the stator windings AA' to FF', and the stator side circuit (2); The fixed component is coaxially mounted on the outer periphery of the rotating component, and a radial air gap with a fixed distance is provided between the two; The cross section of the stator core (21) is similar to that of the stator core of the motor, and is in the shape of a ring. Twelve stator teeth are evenly distributed on the inner circle of the ring along the circumference. Each pair of opposite stator teeth forms a pair. The two stator windings wound on each pair of stator teeth are connected in series and the magnetic flux generated is in the same direction. There are a total of 6 pairs of stator windings (AA'~FF'), which are connected to the control circuit to control the conduction of the windings on each pair of stator teeth. The control circuit is then connected to other stator side circuits (2). There are two connection methods for the control circuit of the stator winding: control circuit E1 or control circuit E2. Control circuit E1 consists of 12 auxiliary switches SP1-SP6, SN1-SN6 and 6 pairs of stator windings AA'~FF'. The specific connection is as follows: each pair of stator windings corresponds to a branch. In each branch, the auxiliary switch SP is first connected in series with the corresponding stator winding, and then connected in series with the auxiliary switch SN. That is, a single branch is a series structure of "SP + stator winding + SN". There are a total of 6 such branches. The two ends of the 6 branches are connected in parallel to form two common connection nodes, denoted as node M and node N. Starting from node M, the resonant capacitor C3 and the resonant inductor Lk2 are connected in series and connected to the AC port of the inverter full bridge H2. The DC side port of the inverter full bridge H2 is connected in series with the filter capacitor C1 and connected to the DC power supply to form the stator side circuit (2). The control circuit E2 consists of 12 auxiliary switches SP1-SP6, SN1-SN6, and 6 pairs of stator windings AA' to FF'. In the control circuit E2, each pair of stator windings first selects one end to connect to a common connection point; the other end of each pair of stator windings is connected to one end of the branch formed by the parallel connection of the two auxiliary switches SP and SN. The other ends of the 6 such parallel branches converge to form an endpoint. From this endpoint, the resonant capacitor C3 and the resonant inductor Lk2 are connected in series to the AC port of the inverter full bridge H2; the DC side port of the inverter full bridge H2 is connected to the DC power supply through the filter capacitor C2, thus forming the stator side circuit (2).

2. The flux-conversion type high-frequency rotating loosely coupled transformer according to claim 1, characterized in that: The stator side circuit (2) consists of a parallel filter capacitor C1, an inverter full bridge H2, a series resonant capacitor C3, and a control circuit E1. The rotor-side circuit (1) consists of a series resonant capacitor C4, a rectifier full-bridge H1, and a filter capacitor C2. The resonant capacitor C3, resonant inductor Lk2, resonant capacitor C4, resonant inductor Lk1, and the high-frequency rotating loosely coupled transformer winding together form a CLLC resonant circuit.

3. The flux-conversion type high-frequency rotating loosely coupled transformer according to claim 2, characterized in that: A series resonant capacitor C3 is connected between the convergence node of the six parallel branches and the AC side port of the inverter full bridge H2. No resonant capacitor C4 is installed on the rotor side.

4. The flux-conversion type high-frequency rotating loosely coupled transformer according to claim 2, characterized in that: A resonant capacitor C3 is connected in parallel on the stator side across the AC side of the stator-side inverter full bridge, and a resonant capacitor C4 is connected in parallel on the rotor side across the AC side of the rotor-side inverter full bridge.

5. The flux-conversion type high-frequency rotating loosely coupled transformer according to claim 2, characterized in that: A resonant capacitor C3 is connected in parallel on the stator side across the AC side of the stator-side inverter full bridge, while no resonant capacitor C4 is provided on the rotor side.

6. The flux-conversion type high-frequency rotating loosely coupled transformer according to claim 1, characterized in that: The rotating assembly includes a rotor core (11), rotor windings (13, 14, 15, 16) and rotor-side circuitry (1); The rotor core (11) has 4 poles, and the four rotor windings (13, 14, 15, 16) are wound on the four pillars of the "+" area in the middle of the rotor core (11) and connected in series to the rotor side circuit (1).

7. The flux-conversion type high-frequency rotating loosely coupled transformer according to claim 1, characterized in that: The rotor core (11) and stator core (21) are made of ultra-thin silicon steel sheets and nanocrystalline materials, and the windings are suitable for Litz wire and copper wire materials.

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