Wireless power transmission assembly and system

Abstract

The invention provides a wireless power transmission assembly and system. The wireless power transmission assembly includes a flexible printed circuit board and a ceramic heat sink. The flexible printed circuit board comprises a Litz winding, wherein the Litz winding is provided with a plurality of layers of wires which are electrically isolated from one another. The ceramic cooling fin is arranged corresponding to the flexible printed circuit board so as to cool the flexible printed circuit board.

Description

Technical Field

[0001] The present disclosure relates to a heat dissipation solution that can transfer heat energy generated by a heat source (such as a winding or a power converter) to an environment, and more particularly to a component suitable for a printed circuit board winding structure for implementing the heat dissipation solution. Background Art

[0002] With the development of wide bandgap semiconductors, power devices that can switch at high frequencies, such as MOSFET (metal-oxide-semiconductor field-effect transistor) and IGBT (insulated gate bipolar transistor), have gradually been widely used in the industry. The use of these devices has opened up new applications for high-frequency power conversion, including but not limited to electric vehicle charging infrastructure, renewable energy integration, active filters and solid-state transformers.

[0003] In the field of electric vehicle charging in particular, WPT (wireless power transfer) has gained a lot of attention in recent years, especially in delivery trucks or other short-distance transportation vehicles with preset driving routes. The growing interest in wireless power transfer is due at least in part to its inherent advantages, such as reduced labor costs, programmability (which allows charging during off-peak hours), and, most importantly, operational safety during the charging process.

[0004] In wireless charging applications (such as electric vehicle charging), the converter typically operates at a high frequency (e.g., about 100 kHz to 200 kHz). For high-power applications, the charging plate can be manufactured using a traditional litz winding structure. For details, please refer to Sun, Y. Xu, J. Wang, R. Burgos, and D. Boroyevich, "Insulation Design of Wireless Auxiliary Power Supply for Medium Voltage Converters," in IEEE Journal of Emerging and Selected Topics in Power Electronics, vol. 9, no. 4, pp. 4200-4211, Aug. 2021, doi: 10.1109 / JESTPE.2020.3011075. Because the litz winding structure or litz wire has lower losses when carrying high-frequency currents, it is generally more popular in high-power applications. In high-power applications that require the transmission of large amounts of high-frequency currents, traditional litz wire is used to make coils, and multiple coils are connected in parallel to achieve the required power. While the use of Litz wire can minimize AC losses, the manufacturing process of Litz wire structures is difficult and not easy to scale up. For example, due to the difference in coupling coefficients between each set of coils, circulating currents and / or significant inductive impedance mismatches may occur, making it difficult to increase the power level by connecting a large number of WPT coils in parallel. In addition, for applications with high power density, the winding method based on traditional Litz wire has limitations. For example, as the size increases, the manufacture of Litz wire usually requires manual assembly, making large-scale production extremely cumbersome and difficult.

[0005] In order to solve the problems faced by traditional Litz wire, a solution based on PCB (printed circuit board) has emerged, which can provide better repeatability and a more convenient manufacturing process. However, even the PCB-based solution has its problems. For example, since the winding structure itself has a certain power loss, the winding structure needs to dissipate heat to maintain the temperature of the winding within a reasonable range.

[0006] In addition, existing heat dissipation solutions also have some defects. For example, coils or windings are usually cooled by natural air cooling or forced air cooling, which respectively dissipates the heat energy generated by the winding structure by sending air to the winding structure or using natural air convection. However, in applications where the coil carries a large current, the heat dissipation area of ​​the coil itself may not be enough to dissipate the heat. In some methods, ferrite cores are used to dissipate heat. For example, ferrite cores are often used to form magnetic field lines, and ferrite cores are good thermal conductors. However, the presence of ferrite structures may hinder the flow of air into the coil, resulting in insufficient or poor heat dissipation of the coil by natural air cooling or forced air cooling. In addition, in some methods, a metal heat sink may be provided between the PCB winding structure and the ferrite core, or a metal heat sink may be provided on the ferrite core, and the ferrite core is located between the PCB winding structure and the metal heat sink. The heat sink is thereby used to promote heat dissipation. In the latter case, a heat transfer path from the coil via the ferrite core to the heat sink can be formed. The provision of a metal heat sink helps to reduce the total thermal resistance on the heat transfer path and helps to maintain the temperature of the winding structure. In some cases, the heat sink itself can be cooled by natural air cooling or forced air cooling. In the structure where the heat sink is provided between the PCB winding structure and the ferrite core, the heat energy (i.e., the main heat source) from the winding structure is directly connected to the heat sink, so it can provide lower thermal resistance and better heat dissipation capacity compared to the aforementioned structure where the heat sink is located at the end of the heat transfer path. In addition, the direct connection between the ferrite core and the heat sink also helps to dissipate heat from the ferrite core. However, the problem with using a metal heat sink is that the magnetic field generated by the winding is not isolated from the metal heat sink, so the metal heat sink provided may cause eddy currents, thereby generating additional currents and losses, and thus resulting in insufficient or poor cooling and reduced efficiency. Summary of the invention

[0007] The purpose of the present disclosure is to provide a wireless power transmission component and system that can be used for charging electric vehicles.

[0008] According to one aspect of the present disclosure, a wireless power transmission component includes a flexible printed circuit board and a ceramic heat sink. The flexible printed circuit board includes a Litz winding, wherein the Litz winding has a plurality of layers of wires electrically isolated from each other. The ceramic heat sink is arranged corresponding to the flexible printed circuit board to dissipate heat from the flexible printed circuit board.

[0009] According to another aspect of the present disclosure, a wireless power transmission system includes a transmitting unit or a receiving unit, wherein the transmitting unit or the receiving unit includes an input stage, a resonator, and a component. The component includes a flexible printed circuit board and a ceramic heat sink. The flexible printed circuit board includes a Litz winding, wherein the Litz winding has a plurality of layers of conductors electrically isolated from each other. The ceramic heat sink is arranged corresponding to the flexible printed circuit board to dissipate heat from the flexible printed circuit board.

[0010] The aforementioned aspects and other aspects of the present invention will be easily understood through the following description of embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The following schematic diagrams may be used to better understand the embodiments of various aspects of the present disclosure. The elements in the drawings are not necessarily drawn to scale, and the focus is on clearly illustrating the principles of the embodiments of the present disclosure. In addition, corresponding parts in these drawings are represented by the same reference numerals.

[0012] Figure 1A FIG. 4 is a schematic diagram of the architecture of a wireless power transmission system according to an embodiment of the present disclosure.

[0013] Figure 1B In one embodiment of the present disclosure, Figure 1A The circuit structure diagram of the part used for wireless power transmission in the wireless power transmission system is shown.

[0014] Figure 2 In one embodiment of the present disclosure, Figure 1A Schematic diagram of the PCB Litz winding structure of the wireless power transmission part shown.

[0015] Figure 3 A partial cross-sectional side view of a flexible PCB Litz winding structure simulating a non-PCB-based Litz winding method in one embodiment of the present disclosure.

[0016] Figure 4A It is a three-dimensional schematic diagram of the Litz winding layout of the flexible PCB Litz winding structure in one embodiment of the present disclosure.

[0017] Figure 4B It is a partial cross-sectional side view of the Litz winding layout of the flexible PCB Litz winding structure in one embodiment of the present disclosure.

[0018] Figure 5A It is a partial three-dimensional schematic diagram of a double-layer flexible PCB Litz winding structure in an embodiment of the present disclosure, wherein the Litz winding simulates a non-PCB-based spiral Litz winding method.

[0019] Figure 5B In one embodiment of the present disclosure Figure 5A A perspective view of the double-layer flexible PCB Litz winding structure and insulation material shown.

[0020] Figure 6 Schematic diagram of waveforms of total losses of a rigid PCB Litz winding structure and a flexible PCB Litz winding structure at a current of 150A and different frequencies in one embodiment of the present disclosure.

[0021] Figure 7FIG. 1 is a waveform diagram showing the percentage of loss reduction of the flexible PCB Litz winding structure compared with the rigid PCB Litz winding structure in one embodiment of the present disclosure, which is based on Figure 6 Performance shown.

[0022] Figure 8 It is a structural schematic diagram of a wireless power transmission component according to an embodiment of the present disclosure, wherein a ceramic heat sink is disposed under a flexible PCB Litz winding structure and is adjacent to the flexible PCB Litz winding structure.

[0023] Fig. 9 It is a schematic structural diagram of a wireless power transmission component according to an embodiment of the present disclosure, wherein a ceramic heat sink is disposed on a flexible PCB Litz winding structure and is adjacent to the flexible PCB Litz winding structure.

[0024] Fig.10 Schematic diagram of the structure of a wireless power transmission component according to an embodiment of the present disclosure, wherein a flexible PCB Litz winding structure is disposed between two ceramic heat sinks located above and below and adjacent to the flexible PCB Litz winding structure.

[0025] Fig.11A It is a schematic diagram of the structure of a component of an embodiment of the present disclosure, wherein the ceramic heat sink is located between the PCB Litz winding structure and the ferrite core.

[0026] Fig. 11B exemplify Fig.11A Thermal resistance network model of the components in .

[0027] Fig. 12A It is a schematic diagram of the structure of a component of an embodiment of the present disclosure, wherein the ceramic heat sink is separated from the PCB Litz winding structure and connected to the ferrite core.

[0028] Fig. 12B exemplify Fig. 12A Thermal resistance network model of the components in .

[0029] Fig.13A It is a schematic diagram of the structure of a component of an embodiment of the present disclosure, wherein the ceramic heat sink is directly connected to the PCB Litz winding structure and is separated from the ferrite core.

[0030] Fig. 13B exemplify Fig.13A Thermal resistance network model of the components in .

[0031] Fig.14A This is a schematic diagram of the structure of a component of an embodiment of the present invention, wherein one ceramic heat sink is directly connected to one side of the PCB Litz winding structure away from the ferrite core, and another ceramic heat sink is connected to the other side of the PCB Litz winding structure and is connected to the ferrite core.

[0032] Fig. 14B exemplify Fig.14A Thermal resistance network model of the components in .

[0033] Fig.15 It is a schematic diagram of the structure of a component of an embodiment of the present disclosure, wherein a PCB Litz winding structure is surrounded by a ceramic heat sink and directly connected to the ceramic heat sink.

[0034] Fig.16 It is a schematic diagram of the structure of a component of an embodiment of the present disclosure, wherein a PCB Litz winding structure is surrounded by a ceramic heat sink and directly connected to a ferrite core.

[0035] Fig.17 It is a schematic structural diagram of a component of an embodiment of the present disclosure, wherein a ceramic heat sink is integrated into a PCB Litz winding structure.

[0036] Explanation of symbols

[0037] 10: Wireless power transmission system

[0038] 12: Transmitter unit

[0039] 14: Receiving unit

[0040] 15: Input stage

[0041] 16, 17: Resonator

[0042] 18: Output stage

[0043] 19: Controller

[0044] 20: Wireless power transmission coil system

[0045] v dc,in : Input voltage

[0046] v dc,out : Output voltage

[0047] C in : Input capacitance

[0048] C out : Output capacitor

[0049] Q 1 , Q 2 , Q 3 , Q 4 , Q 5 , Q 6 , Q 7 , Q 8 :switch

[0050] C 1 , C 2 :capacitance

[0051] 20a: Flexible PCB Litz winding structure

[0052] 22: Litz winding

[0053] 28: Flexible PCB Litz winding structure

[0054] 30: Litz winding

[0055] 32a, 32b, 32c, 32d: Layer

[0056] 34: Flexible insulation layer

[0057] 36: Leeds winding layout

[0058] 38: Wire

[0059] 40: Double-layer flexible PCB Litz winding structure

[0060] 42: First floor

[0061] 44: Second floor

[0062] 46: Wire

[0063] 48: Thick line

[0064] 50: Through hole

[0065] 40a: Double-layer flexible PCB Litz winding structure

[0066] 52: Insulation material

[0067] x, y: direction

[0068] 54: Waveform

[0069] 56, 58: Curve

[0070] 60: Waveform

[0071] 62a: Wireless power transmission components

[0072] 64: Ceramic heat sink

[0073] 66: Flexible PCB Litz winding structure

[0074] 68: Heat Source

[0075] 70: Fluid channel

[0076] 72: Arrow

[0077] 62b, 62c: Wireless power transmission components

[0078] 64a, 64b: Ceramic heat sink

[0079] 70a, 70b: Fluid channel

[0080] 73a: Components

[0081] 78: Ceramic heat sink

[0082] 74: PCB Litz winding structure

[0083] 82: Ferrite core

[0084] 76: Heat Source

[0085] 80: Fluid channel

[0086] 84, 86, 88, 90: Arrows

[0087] 92: Thermal resistance network model

[0088] AT: Ambient temperature

[0089] HS1, HS2: Heat source

[0090] C th0,c , C th0,w , C th1,c , C th1,w , C th,hs : Heat capacity

[0091] R th0,c , R th0,w , R th1,c , R th1,w , R th,hs : Thermal resistance

[0092] 73b: Components

[0093] 94, 96, 98: Arrow

[0094] 99: Thermal resistance network model

[0095] 73c: Components

[0096] 100, 102, 104: Arrow

[0097] 106: Thermal resistance network model

[0098] 73d: Components

[0099] 78a, 78b: Ceramic heat sink

[0100] 80a, 80b: Fluid channel

[0101] 108, 110, 112, 114: Arrows

[0102] 116: Thermal resistance network model

[0103] 73e: Components

[0104] 82a, 82b: Ferrite core

[0105] 118, 120, 122, 124, 126, 128: Arrows

[0106] 73f: Components

[0107] 130, 132, 134, 136: Arrows

[0108] 73g: Components

[0109] 138, 140, 142, 144: Arrows DETAILED DESCRIPTION

[0110] The present disclosure discloses some embodiments of systems and components, wherein the systems and components include a PCB-based Litz winding or coil structure and a ceramic heat sink, which helps to dissipate heat from heat sources inside and around the component. In one embodiment, the component is used in a WPT system and includes a flexible PCB, wherein the WPT system can be used, for example, for charging electric vehicles, and the flexible PCB includes a Litz winding or coil. The coil includes multiple layers of wires. In one embodiment, the wire can be configured as a plurality of electrically insulated conductive lines, and the plurality of conductive lines are connected between the multiple layers to simulate non-PCB-based Litz wires. For example, each of the plurality of wires in a layer is an electrically insulated conductive line (e.g., an annealed copper line) connected in series between the multiple layers (e.g., through a through hole), thereby simulating the spiral or vortex style of a general Litz winding structure. In addition, the component also includes a ceramic heat sink, wherein the ceramic heat sink is arranged corresponding to the flexible PCB Litz winding structure to dissipate heat from the coil.

[0111] Existing PCB Litz windings can reduce high frequency AC losses (compared to traditional copper conductors) by simulating (non-PCB-based) Litz wire, where the Litz winding is included in a PCB structure and is cut into multiple independent conductors (e.g., each conductor in a layer is serially connected to another conductor in another layer using a through hole), and then the independent conductors in multiple layers are woven in the same manner as a traditional Litz wire structure. As described above, this structure simulates (non-PCB-based) Litz wire (and its characteristics) through the PCB without using traditional Litz wire. Compared to existing PCB structures, this method of simulating Litz wire on a PCB structure can help reduce AC losses. For more information about PCB Litz-Wire structures, see I. Lope, J. Acero, JM Burdío, C. Carretero, and R. Alonso, "Design and Implementation of PCB Inductors With Litz-Wire Structure for Conventional-Size Large-Signal Domestic Induction Heating Applications," in IEEE Transactions on Industry Applications, vol. 51, no. 3, pp. 2434-2442, May-June 2015, doi: 10.1109 / TIA.2014.2382758 and U.S. Patent No. 7,973,635 B2. One disadvantage of the existing structure is that at least two layers of PCB are used for each wire to achieve the desired effect. Although this is an effective technique for reducing AC losses, it is still difficult to dissipate heat from the inner layers of the PCB due to the low thermal conductivity of PCB insulation materials (usually in the range of 0.3W / mK to 0.6W / mK) and the minimum interlayer thickness (e.g., about 10 mils). Furthermore, it is difficult to reduce the thickness of the dielectric layer because it increases the risk of cracks (which may affect reliability). Due to the thickness of the insulation materials commonly used in existing methods (e.g., FR4 materials), it is difficult to dissipate the heat generated by the PCB winding, which makes it difficult for the winding structure to operate at high power.

[0112] As can be seen from the above, existing heat dissipation solutions also have some problems. For example, although metal heat sinks can provide good heat dissipation performance and are relatively easy to manufacture, due to their conductivity, they cannot provide electrical isolation whether in the solution where the metal heat sink is located between the PCB winding structure and the ferrite core, or in the solution where the ferrite core is located between the PCB winding structure and the metal heat sink. For applications that focus on electrical isolation, it may be necessary to set additional insulating materials between the heat sources, which will increase thermal resistance and reduce heat dissipation performance. When expanded to higher power applications, these problems will become more serious.

[0113] In contrast, the present disclosure provides some embodiments of systems and components including a PCB Litz winding structure and a ceramic heat sink, which combine a flexible PCB structure with a smaller thickness and the heat dissipation effect of a ceramic heat sink to overcome the heat dissipation problems faced when using existing PCB structures, while at the same time providing electrical isolation that existing metal heat sinks do not have.

[0114] After summarizing the features of the components (including PCB winding structures and ceramic heat sinks) proposed in the present disclosure, the components in the accompanying drawings will now be described in detail. Although the following description will be combined with the accompanying drawings, and focus on the Litz winding structure and ceramic heat sink based on a flexible PCB or a flexible PCB for wireless power transmission applications (especially wireless electric vehicle charging applications), the present disclosure is not limited to the illustrated embodiments. For example, in some embodiments, a rigid PCB Litz winding structure and a ceramic heat sink may also be used for a PCB-based Litz winding component. For example, a rigid PCB Litz winding component may include a magnetic core (e.g., a ferrite core) for wired applications. In addition, although the specific features of certain embodiments are mentioned or described in the description, these specific features are not necessarily applicable to every embodiment, nor are all the advantages mentioned related to a single embodiment. The purpose of the description is to cover all alternatives, modifications, and equivalents within the principles and scope defined in the appended claims. For example, two or more embodiments may be interchanged or combined in any combination. Furthermore, it should be understood that the claims of the present disclosure are not limited to the embodiments illustrated in the description.

[0115] In the following description, unless otherwise specified, the PCB Litz winding assembly may include a rigid or flexible PCB structure and may or may not include a ferrite core. In addition, the PCB Litz winding structure should be understood as a PCB that simulates an existing Litz wire (e.g., a Litz wire used in a non-PCB implementation) and a Litz winding or coil disposed on the PCB. The "wire" and "winding" herein correspond to existing non-PCB-based Litz winding methods, while "coil", "winding" and "winding structure" correspond to PCB winding arrangements that simulate non-PCB-based Litz wire configurations and functions. Although ceramic heat sinks are not shown in some of the drawings of different components, it should be understood that ceramic heat sinks can be expected to be used in any of the PCB Litz winding structures shown.

[0116] In addition, it should be noted that “coil”, “winding”, “winding structure” and similar terms can be used interchangeably in the description of this disclosure.

[0117] As described above, the present disclosure proposes some embodiments of components (such as WPT components), wherein the components combine the heat dissipation advantages of a flexible PCB structure and a correspondingly arranged ceramic heat sink. For example, a flexible PCB Litz winding structure can be used for power transmission, and has low losses and good thermal conductivity, and is easier to manufacture than existing rigid PCB Litz winding designs or non-PCB-based Litz wire designs. The flexible PCB Litz winding structure can limit the temperature of the copper wire winding structure to improve the heat dissipation performance, thereby allowing operation at a higher current. In addition, the heat dissipation solution provided by the ceramic heat sink can effectively extract heat energy from heat sources (such as windings and / or ferrite cores, or even heat sources in other components close to the component (such as adjacent or temporarily close)), wherein the position of the ceramic heat sink can be adjusted according to design requirements. The ceramic heat sink also provides electrical insulation, which can further improve the heat dissipation performance compared to metal thermal conductive pads. Specifically, the ceramic heat sink can directly contact the winding (for example, the winding is abutted against the ceramic heat sink, and a thermally conductive adhesive can be used) without insulation (that is, there is no insulation or air gap between the winding and the ceramic heat sink), thereby reducing the thermal resistance between the winding and the ceramic heat sink. Furthermore, the ceramic heat sink can be directly connected to the winding and the ferrite core (if provided), and no additional loss will be generated while dissipating heat from the winding and the ferrite core.

[0118] Figure 1ASchematic diagram of the architecture of a wireless power transmission (WPT) system 10 according to an embodiment of the present disclosure. The wireless power transmission system 10 is suitable for charging electric vehicles and other applications involving wireless power transmission, especially high-power and high-frequency applications. The wireless power transmission system 10 includes a transmitting unit 12 and a receiving unit 14. The transmitting unit 12 can be disposed at a charging station (such as a retail or public charging station) or a charging plate (such as a charging plate located in a residential garage) for charging electric vehicles. The receiving unit 14 can be disposed in an electric vehicle. In the illustrated embodiment, the transmitting unit 12 includes an input stage 15 and a resonator 16.

[0119] The input stage 15 receives input electrical energy and converts the input electrical energy into AC electrical energy suitable for the resonator 16. For example, the input stage 15 can be connected to an AC power source that provides AC input electrical energy. In one embodiment, the input stage 15 has the function of performing AC / DC, DC / DC and DC / AC conversion. For example, an AC / DC converter can be used to convert the AC input electrical energy into a fixed DC intermediate electrical energy (e.g., 800V), and then the fixed DC intermediate electrical energy can be converted into a variable DC intermediate electrical energy (e.g., 0V to 800V) through a DC / DC converter, and then the variable DC intermediate electrical energy is input into an inverter (e.g., including multiple switches for controlling duty cycle and frequency). In some embodiments, the DC / DC conversion process can be omitted.

[0120] The resonator 16 includes a tuned circuit (e.g., including a resistor, a capacitor, and a PCB coil connected in series). By applying AC power to the input of the resonator 16, the resonator 16 begins to oscillate to generate a magnetic field in the space around the resonator 16. In some cases, a ferrite core (e.g., in non-WPT applications) can be used to guide the direction of the magnetic field according to specific application requirements.

[0121] The receiving unit 14 includes a resonator 17 and an output stage 18. The resonator 17 captures the magnetic field generated by the resonator 16 and converts the energy received through the magnetic field into an AC output. The resonator 17 generally corresponds to the resonator 16 and also includes a tuning circuit formed by a resistor, a capacitor and a PCB coil connected in series. By appropriately placing the resonator 17 in the magnetic field generated by the resonator 16, the resonator 17 can capture the energy transmitted through the magnetic field and convert it into an AC output. Similar to the resonator 16, the resonator 17 may also include a ferrite core in some embodiments.

[0122] The output stage 18 receives the AC output from the resonator 17, converts the AC output into a DC output, and provides the DC output as output power to a specific load (e.g., charging an electric vehicle battery). For example, the output stage 18 may include an AC / DC converter connected to the output end of the resonator 17, wherein the AC / DC converter converts the AC power received at its input end into DC output power. The AC / DC converter may include a synchronous rectifier, a bulk capacitor, and an output filter, wherein the bulk capacitor and the output filter are connected after the synchronous rectifier and are used to shape the DC output power.

[0123] The controller 19 controls the transmission of power from the transmitting unit 12 to the receiving unit 14 through the air gap, and controls the power provided to the load connected to the output stage 18, such as to meet the requirements of a specific application (meeting the specific output power required by the device connected to the output stage 18). For example, when the load includes a battery charged by the wireless power transmission system 10, the controller 19 may receive a power setting value from the load (such as a current setting value from a battery management system of the load battery). The controller 19 (or another controller in communication with the controller 19) may include a current sensing function (such as for measuring the AC output from the resonator 17 or the DC output from the output stage 18). The controller 19 may generate a control signal using the sensed current (and the current setting value) to control the transmitting unit 12 (such as for generating a magnetic field that meets the required output power) through the control signal.

[0124] The transmitting unit 12 and the receiving unit 14 may also include other functions, such as a communication interface (not shown), which can facilitate the cooperation between various systems and devices (for example, in charging applications, the cooperation between the battery management system and the wireless power transmission system 10). It should be noted that the circuits of the transmitting unit 12 and the receiving unit 14 can be digital, analog or mixed signal electronic devices, and can be implemented by one or more processors (such as digital signal processors) and logic gates, etc. Since the composition of such circuits is common knowledge in the art, it will not be repeated here.

[0125] It should be noted that in some embodiments, the functions of the input stage 15 and the resonator 16 can be integrated into a single PCB or distributed in multiple PCB structures. Similarly, the functions of the output stage 18 and the resonator 17 can also be integrated into a single PCB or distributed in multiple PCB structures.

[0126] Figure 1B exemplify Figure 1AThe circuit structure of the wireless power transmission system 10 in FIG. 1 is shown, and the wireless power transmission coil system 20 is emphasized. The system schematically represents the resonators 16 and 17 with the transmitting unit coil and the receiving unit coil, respectively. For example, the high frequency current flowing through the transmitting unit coil generates a magnetic field, which propagates in the air and passes through the receiving unit coil, thereby generating a current in the receiving unit coil, and finally using the current to charge the electric vehicle.

[0127] Figure 2 A flexible PCB Litz winding structure 20a is shown, which is suitable for wireless power transmission. For example, it can achieve Figure 1B The functions required for the wireless power transmission coil system 20 in the embodiment are described in detail, especially for the transmitting side PCB coil of the resonator 16, but the following description is also applicable to the receiving side PCB coil of the resonator 17. In this example, the flexible PCB Litz winding structure 20a includes a flexible PCB, wherein the flexible PCB includes a Litz winding 22. The Litz winding 22 includes a plurality of conductors or lines (e.g., a plurality of lines connected in series and electrically insulated from each other), and the plurality of conductors or lines may be arranged in multiple layers to simulate non-PCB-based Litz wires, which will be described in detail later. In addition, although the Litz winding 22 in this example is a circular geometric structure, in some embodiments, the Litz winding 22 may also be configured in other shapes (e.g., rectangular).

[0128] Figure 3 An embodiment of a flexible PCB Litz winding structure 28 is shown. The flexible PCB Litz winding structure 28 includes a Litz winding 30 that simulates a Litz wire (not PCB based). The flexible PCB Litz winding structure 28 can be connected to Figure 2The flexible PCB Litz winding structure 20a shown is the same or similar. In this embodiment, the Litz winding 30 has multiple layers, such as layers 32a, 32b, 32c and 32d (generally referred to as layers 32). Although four layers are shown in the figure, other numbers of layers can actually be used, such as two to fifteen layers, but it is not limited to this range. In short, although the more layers, the better the performance, the choice of the number of layers also depends on factors such as power requirements, manufacturing difficulty and cost. For example, a structure with fifteen layers can provide excellent performance, but it is more difficult to manufacture (and therefore more expensive) than a structure with fewer layers, and in fact, it may not be necessary to use such a structure with so many layers in low-cost applications. The layers 32 are electrically insulated by a flexible insulating layer 34. In one embodiment, the distance between adjacent layers 32 (or equivalent to the thickness of the flexible insulating layer 34 between layers) is about 1 mil to 10 mils. In addition, the distance between the outer layer 32 and the edge of the flexible PCB Litz winding structure 28 (or the thickness of the flexible insulating layer 34 between the outer layers 32a and 32d and the edge of the flexible PCB Litz winding structure 28) can be about 1 mil to 10 mils, but it is not limited to the same distance as the distance between adjacent layers 32. The non-conductive material of the flexible PCB Litz winding structure, or more precisely the flexible insulating layer 34 (such as PCB structure material), can be formed of polyester, adhesive polyamide or non-adhesive polyamide. Other flexible insulating materials can also be used in other embodiments. The insulating material used depends on the actual application requirements. In contrast, the rigid PCB Litz winding structure is usually made of different types of polyamide (such as FR4). Because it is rigid, it is easy to break when bent. For example, in terms of bending with the same radius, the rigid PCB is more likely to break than the flexible PCB. The thickness of the interlayer insulating material of the rigid PCB Litz winding structure is usually 10 mils or more, and this thickness also increases the rigidity, especially when the number of layers is increased. In addition, the thickness of the rigid PCB Litz winding structure makes it difficult to dissipate heat, especially for the inner layer. In contrast, the flexible PCB Litz winding structure 28 has a smaller insulating material thickness, so it can provide a better heat conduction path and dissipate more heat energy than the rigid PCB Litz winding structure. The Litz winding 30 is also made of flexible conductive material, which can include metal conductive material (such as bendable annealed copper) or non-metallic conductive material (such as made of graphene material).

[0129] Figure 4A and Figure 4B An example of a flexible PCB Litz winding structure (eg Figure 3 Flexible PCB Litz winding structure in 28 or Figure 2The Litz winding layout 36 of the flexible PCB Litz winding structure 20a) in FIG. The Litz winding layout 36 provides a technique for reducing high frequency AC losses by splitting the conductor (e.g., copper conductor) in the flexible PCB Litz winding structure into multiple independent wires or lines, thereby simulating the existing Litz wire structure, wherein the multiple wires or lines can be collectively referred to as a wire bundle. It should be noted that each wire includes a continuous conductive line that can be connected in series with another wire using a through hole. See Figure 4A In this example, three wires form a wire harness (or a coil), wherein the wires are electrically isolated from each other (e.g., by insulating material between the wires in the PCB structure). Figure 4A From the path of one of the wires 38 from left to right, it can be seen that this is a spiral winding layout, in which the wire 38 starts from one of the layers (the first layer) and extends at a certain angle, or in other words, across the width of the harness along the plane where the first layer is located. Then, after crossing the width of the harness and reaching the through hole (not shown), the through hole allows the wire 38 to continue to extend on another layer. When the wire 38 crosses the width of the harness again along the second plane and reaches the second through hole, the second through hole allows the wire 38 to return to the top layer or the initial layer. It can be seen that the first section can be understood as the length of the wire 38 along the first layer in one direction, and the second section can be understood as the length of the wire 38 along the second layer in another direction, and the first section and the second section are connected in series with each other via the through hole. Other wires in the harness can also be arranged in a similar manner. Therefore, the wire 38 (the same applies to other wires) is arranged in a spiral shape, so it can simulate the existing Litz wire in structure and function. Since each wire passes through a specific position in the harness, all wires or windings are spatially equivalent. As shown Figure 4B As shown, it shows the induced voltage (+V) generated between a pair of conductors or lines. It should be noted that for the flexible PCB Litz winding structure, since the flexible PCB Litz winding structure is more flexible than the rigid PCB Litz winding structure, the Litz winding layout 36 can adopt different shapes and structures according to requirements.

[0130] Figure 5A A double-layer flexible PCB Litz winding structure 40 is illustrated, which simulates a Litz wire wound in a spiral shape. The double-layer flexible PCB Litz winding structure 40 can be used (or extended to be used) for any flexible PCB Litz winding structure described above (or described later). The double-layer flexible PCB Litz winding structure 40 includes a first layer 42 of wires or lines, a second layer 44 of wires or lines, and a flexible insulating layer (illustrated in FIG. 4 ) between the first layer 42 and the second layer 44. Figure 5B In this example, there are five wires that are electrically isolated from each other (e.g., by insulating material between the wires). Figure 5A4 (not shown), wherein the path of one of the wires 46 is depicted by a thick line 48 to illustrate the helical winding structure of the wire. It should be noted that in some embodiments, a fewer or more number of wires may be used. Figure 4A and Figure 4B In the Litz winding layout 36, the conductor 46 (shown as thick line 48) spans the width of the wire bundle on the first layer 42 until it reaches the through hole 50 (the through hole 50 is covered by the thick line 48, but its structure is the same as Figure 5A The via 50 allows a conductive connection (e.g., a series connection) between the first layer 42 and the second layer 44. In this example, the via 50 allows the conductor 46 to effectively (conductively) extend to the second layer 44 and continue along the path shown by the thick line 48 (e.g., extend to another via), and then connect to the first layer 42 again (e.g., through the via), and repeat the wiring. As described above, the first layer 42 and the second layer 44 and the conductors in the layers are electrically isolated from each other by the insulating material located between them, such as Figure 5B The insulating material 52 of the double-layer flexible PCB Litz winding structure 40a is shown, wherein the double-layer flexible PCB Litz winding structure 40a is similar to 40, and Figure 5B The double-layer flexible PCB Litz winding structure 40a in FIG. 4 further shows an insulating material 52. As mentioned above, the thickness of the insulating material 52 is about 1 mil to 10 mils to effectively dissipate heat from a heat source (such as a coil). Figure 5A and Figure 5B In the embodiment shown in each layer has a single turn of multiple conductors, but in other embodiments, there may be more turns, for example, can be replicated Figure 5A and Figure 5B The wire shown in the figure is used to realize the winding of double turns, for example, in each layer, an additional set of wires is arranged adjacent to the wire shown in the figure along direction x. In addition, more layers of wires (for example, additionally arranged along direction y) and / or different numbers of wires can be arranged in each layer.

[0131] It is also important to note that the interlayer distance is related to the proximity effect and the current distribution in each layer. For example, for a specific current flowing through a rigid PCB coil structure, due to the proximity effect, it can be observed that the current distribution is not uniform, which leads to different losses in each layer and increases the total loss. The extent of this proximity effect depends on the interlayer distance. In a rigid PCB Litz winding structure, the minimum distance between layers is close to 10 mils, resulting in higher proximity losses in the winding. In contrast, in a flexible PCB Litz winding structure, since the interlayer distance can be reduced to 1 mil, the total losses in the winding are lower at the same current amplitude and frequency.

[0132] Figure 6A waveform diagram 54 is shown, wherein the waveform diagram 54 illustrates the total loss of a rigid PCB Litz winding structure and a flexible PCB Litz winding structure at a current of 150A and different frequencies. In the waveform diagram 54, the vertical axis represents AC loss (watts) and the horizontal axis represents frequency (kilohertz). For example, the rigid PCB Litz winding structure includes eight layers and four turns, and each winding path can be divided into twelve conductors evenly distributed in two layers, thereby forming an interwoven Litz winding structure. The distance between each layer is maintained at 10 mils, which is the minimum interlayer distance that can be achieved in the rigid PCB Litz winding structure. However, in a flexible PCB Litz winding structure with the same number of conductors and layers, the distance between each layer can be reduced to 1 mil. When the current flowing through the winding is 150A and the frequency is in the range of 0 Hz (DC) to 600 kHz, the total loss of the rigid PCB Litz winding structure exemplified is represented by curve 56, and the total loss of the flexible PCB Litz winding structure exemplified is represented by curve 58. It can be observed that the two structures have the same loss at DC, but at high frequencies, the loss of the flexible PCB Litz winding structure is significantly lower than that of the rigid PCB Litz winding structure. In addition, for the flexible PCB Litz winding structure, since lower losses usually mean lower heat dissipation requirements, design considerations can include balancing heat dissipation in the internal winding (e.g., on the tenth to fifteenth layers) and reducing AC losses.

[0133] Figure 7 Shown based on Figure 6 The waveform diagram 60 of the performance is shown. In the waveform diagram 60, the vertical axis represents efficiency (percentage) and the horizontal axis represents frequency (kilohertz). Figure 6 The performance shown in the waveform diagram shows the percentage of loss reduction of the flexible PCB Litz winding structure compared to the rigid PCB Litz winding structure. It can be observed that when the flexible PCB Litz winding structure operates at a frequency close to 200 kHz, the loss can be reduced by about half compared to the rigid PCB Litz winding structure. Therefore, in this frequency range, the operation of the flexible PCB Litz winding structure is more ideal.

[0134] After describing some differences between the flexible PCB Litz winding structure and the rigid PCB Litz winding structure, Figures 8 to 10 Some embodiments of wireless power transmission components are illustrated, wherein the wireless power transmission component combines a flexible PCB Litz winding structure and a ceramic heat sink (also known as a cooling plate). Figures 8 to 10 The WPT components shown in the example can be applied to WPT systems (e.g. Figure 1A WPT system 10). Figures 8 to 10 The illustrated components are particularly suitable for wireless power transmission in electric vehicle charging applications. In the subsequent description, the various flexible PCB Litz winding structures mentioned previously can be used as Figures 8 to 10The components shown can be combined in any form in a wireless power transmission system. For example, Figure 8 The components shown can be used in a transmitting unit, and Fig. 9 or Fig.10 The components shown can be used in the receiving unit and vice versa. FIG. 11A to FIG. 17 Various rigid PCB Litz winding structures are illustrated for non-wireless applications where the heat source includes a ferrite core in addition to the Litz winding.

[0135] Slightly off topic, a ceramic heat sink can be provided as a heat dissipation solution to efficiently remove heat energy from a heat source, such as a Litz wire winding (in applications using a ferrite core structure, the ferrite core also forms a heat source). In some embodiments, the heat source may come from other components or devices. For example, the heat source may be a transmitter unit (e.g., a PCB) that includes a flexible PCB Litz winding structure. Figure 1A The transmitting unit 12 in the embodiment of the present invention may be provided with other elements together with the transmitting unit 12 in the embodiment of the present invention, such as elements located on another PCB (such as a circuit provided with the input stage 15), or elements temporarily close to the flexible PCB Leeds winding structure (such as elements of the receiving unit on a vehicle driving into a charging station provided with the transmitting unit). In these cases, a ceramic heat sink may be used to conduct away the heat energy generated by the heat source, wherein the ceramic heat sink may be made of various ceramic materials, and in some embodiments, the ceramic heat sink may be manufactured to have one or more channels (such as pipes, conduits, and delivery pipes, etc.) for fluid flow inside to promote the heat dissipation effect by fluid flow (such as flow under controllable pressure or flow by gravity). The position of the ceramic heat sink may be adjusted according to design requirements. Compared with metal heat sinks, ceramic heat sinks can provide the required insulation effect while enhancing heat dissipation. For example, unlike metal heat sinks, ceramic heat sinks are electrically insulated, so the magnetic field generated by the windings will not cause additional losses on the ceramic heat sink. Therefore, the ceramic heat sink does not substantially generate eddy current losses. According to at least some of the thermal models of the components shown, heat energy from heat sources (such as the Litz winding and the ferrite core (if used)) can be effectively dissipated through the ceramic heat sink. The ceramic heat sink provides a low thermal resistance route for the heat transfer path, which helps to keep the temperature of the heat source within a normal range. In fact, by properly arranging the ceramic heat sink with respect to the Litz winding, better heat dissipation can be achieved and the thermal stress on the Litz winding (as well as the ferrite core (if used) and other heat sources close to the ceramic heat sink) can be reduced.

[0136] First, the following will take the wireless power transmission components used for charging electric vehicles as an example, and Figures 8 to 10 to describe. Figure 8A wireless power transmission component 62a according to an embodiment of the present disclosure is illustrated, wherein a ceramic heat sink 64 is disposed under (located under and / or connected to or in contact with) a flexible PCB Litz winding structure 66 and is adjacent to the flexible PCB Litz winding structure 66 (also referred to as a flexible PCB structure, a flexible PCB, or similar names), wherein the flexible PCB Litz winding structure 66 includes a heat source (e.g., a Litz winding) 68. For example, the PCB may extend along a specific plane, and the ceramic heat sink 64 may be disposed on the PCB by screws or other fixing mechanisms. The flexible PCB Litz winding structure 66 includes a material (e.g., a flexible PCB structure) having softness and insulation properties. Figure 3 The flexible insulating layer 34 or Figure 5B The ceramic heat sink 64 also includes a flexible insulating material 52, which includes the structural material of the PCB. In the illustrated embodiment, the ceramic heat sink 64 also includes a fluid channel 70, which helps to dissipate heat from the heat source 68. The coolant can be water or ethylene glycol, for example. The number or arrangement of the fluid channels 70 can be different from the number of channels 70. Figure 8 The examples in (can also be similar to or different from Figures 9 to 17 In some other embodiments, the fluid channel 70 may be omitted. The arrow 72 in the figure represents the heat transfer path. In this embodiment, the heat transfer path is from the heat source 68 (such as the Litz winding) to the ceramic heat sink 64.

[0137] Fig. 9 Another embodiment of the wireless power transmission component 62b of the present disclosure is illustrated, wherein a ceramic heat sink 64 (including a fluid channel 70) is disposed on and adjacent to a flexible PCB Litz winding structure 66. Figure 8 In some embodiments, the wireless power transmission component (or FIG. 11A to FIG. 17 The fluid passage in other components in the heat sink 64 can be omitted. Arrow 72 also indicates the heat transfer path, which in this embodiment is from the heat source 68 (such as the Litz winding) to the ceramic heat sink 64.

[0138] Fig.10 A wireless power transmission component (or system) 62c of another embodiment of the present disclosure is illustrated. A flexible PCB Litz winding structure 66 is disposed between two ceramic heat sinks located above and below and adjacent thereto. In this embodiment, the two ceramic heat sinks include ceramic heat sinks 64a and 64b, and the ceramic heat sinks 64a and 64b include fluid channels 70a and 70b, respectively. The coolant may be provided from a single source and distributed to the corresponding fluid channels 70a and 70b (e.g., using a valve), or the fluid channels 70a and 70b each have a separate source of coolant. Two arrows 72 represent heat transfer paths from a heat source 68 (e.g., Litz wire) to the ceramic heat sinks 64a and 64b, respectively.

[0139] According to actual design requirements, the wireless power transmission system can adopt the following methods for the transmitting unit and / or the receiving unit: Figures 8 to 10 In addition, the ceramic heat sink 64 can not only dissipate heat for the wireless power transmission components (such as the wireless power transmission component 62a, the wireless power transmission component 62b and / or the wireless power transmission component 62c), but also dissipate heat for other components. For example, the ceramic heat sink 64 is also used to transfer heat energy generated by the power converter or adjacent electronic components in the electric vehicle.

[0140] As previously mentioned, in the embodiments of the present disclosure, the system or component including the PCB Litz winding structure and the ceramic heat sink is not limited to the flexible PCB Litz winding structure or wireless power transmission application. FIG. 11A to FIG. 17 Examples of systems or components using rigid PCB Litz winding structures in various wired applications are shown, wherein the wired applications involve power transmission and contain ferrite cores. It should be noted that the description of "adjacent to another structure" or "disposed between structures" should be understood as being adjacent to the structure in position and directly connected to the structure, which can be connected by screws or clamps, and thermally and electrically conductive materials can be selected.

[0141] Fig.11A 7a of an embodiment of the present disclosure is shown, wherein a ceramic heat sink 78 is located between a PCB Litz winding structure 74 and a ferrite core 82 (the ferrite core 82 is indicated by a dashed line). For example, the ceramic heat sink 78 can be connected to the ferrite core 82 by screws or clamps, and a heat dissipation dielectric material can be used between the ferrite core 82 and the ceramic heat sink 78 to improve thermal conductivity (i.e., heat transfer). Similar to the previous description for wireless power transmission applications, and applicable to FIG. 12A to FIG. 17 The components shown in the figure, the PCB Litz winding structure 74 includes a heat source 76, wherein the heat source 76 includes a Litz winding. The PCB Litz winding structure 74 is made of a rigid PCB material (such as a rigid insulating material such as FR4). In one embodiment, the ceramic heat sink 78 includes one or more fluid channels, such as a fluid channel 80 shown in the figure. In other embodiments, the heat sink 78 may be omitted. FIG. 11A to FIG. 17 Fluid channels in a ceramic heat sink.

[0142] Fig.11A Also shown are several arrows 84, 86, 88 and 90 representing heat transfer paths. Fig.11A From top to bottom in the perspective of FIG. 8 , arrow 84 represents a secondary heat transfer path (starting from heat source 76), arrow 86 represents a primary heat transfer path from heat source 76 to ceramic heat sink 78, arrow 88 represents a primary heat transfer path from ferrite core 82 to ceramic heat sink 78, and arrow 90 represents a secondary heat transfer path from ferrite core 82 to the surrounding environment (air). Similar to the example for FIG. Figure 8 As described above, component 73a provides a heat dissipation solution. Unlike metal heat sinks, since ceramic heat sink 78 is electrically insulated, the magnetic field generated by the winding (heat source 76) will not cause additional losses on the ceramic heat sink 78. Therefore, the ceramic heat sink 78 will not generate eddy current losses. As shown in the thermal model of component 73a (see Fig. 11B ), heat energy from two heat sources (including the heat source 76 associated with the winding and the ferrite core 82) can be effectively dissipated through the ceramic heat sink 78. The ceramic heat sink 78 provides a low thermal resistance route for the heat transfer path, which helps to keep the temperature of the heat source within a normal range.

[0143] Fig. 11B exemplify Fig.11A The thermal resistance network model 92 of the component 73a in FIG. The thermal resistance network model 92 includes several parameters, which are described below one by one. AT represents the ambient temperature, HS1 represents the heat source formed by the ferrite core 82, HS2 represents the heat source 76 formed by the winding, C th0,c represents the heat capacity of the bottom of the ferrite core 82, R th0,c represents the thermal resistance between the bottom of the ferrite core 82 and the environment, C th0,w represents the thermal capacitance of the top of the PCB Litz winding structure 74, R th0,w represents the thermal resistance between the top of the PCB Litz winding structure 74 and the environment, C th1,c represents the thermal capacitance of the top of the ferrite core 82, R th1,c represents the thermal resistance between the top of the ferrite core 82 and the ceramic heat sink 78, C th1,w represents the thermal capacitance of the bottom of the PCB Litz winding structure 74, R th1,w represents the thermal resistance between the bottom of the PCB Litz winding structure 74 and the ceramic heat sink 78, C th,hs represents the heat capacity of the ceramic heat sink 78, R th,hs represents the thermal resistance between the ceramic heat sink 78 and the environment. As described above, unlike the metal heat sink, the ceramic heat sink 78 is electrically insulated, so there is no eddy current loss on the ceramic heat sink 78, and thus the heat source associated with the heat sink can be omitted in the thermal resistance network model 92.

[0144] Fig. 12A The component 73b of an embodiment of the present disclosure is illustrated, wherein the ceramic heat sink 78 is separated from the PCB Litz winding structure 74 and connected to the ferrite core 82. In other words, the ferrite core 82 is located between the PCB Litz winding structure 74 and the ceramic heat sink 78. Fig. 12AThe arrows used to represent the heat transfer paths are described in order from top to bottom from the perspective of FIG. 9 . Arrow 94 represents the secondary heat transfer path from the heat source 76 and the ferrite core 82, arrow 96 represents the primary heat transfer path from the heat source 76 to the ferrite core 82, and arrow 98 represents the primary heat transfer path from the ferrite core 82 to the ceramic heat sink 78. As shown in the corresponding thermal model (see FIG. Fig. 12B ), the heat energy from the heat source 76 reaches the ceramic heat sink 78 via the ferrite core 82 (which itself has a certain thermal resistance).

[0145] Fig. 12B exemplify Fig. 12A The thermal resistance network model 99 of the component 73b in FIG. The thermal resistance network model 99 includes several parameters, which are described below one by one. AT represents the ambient temperature, HS1 represents the heat source formed by the ferrite core 82, HS2 represents the heat source 76 formed by the winding, C th0,w represents the thermal capacitance of the top of the PCB Litz winding structure 74, R th0,w represents the thermal resistance between the top of the PCB Litz winding structure 74 and the environment, C th1w represents the thermal capacitance of the bottom of the PCB Litz winding structure 74, R th1w represents the thermal resistance between the bottom of the PCB Litz winding structure 74 and the ferrite core 82, C th0,c represents the thermal capacitance of the top of the ferrite core 82, R th0,c represents the thermal resistance between the top of the ferrite core 82 and the PCB Litz winding structure 74, C th1,c represents the heat capacity of the bottom of the ferrite core 82, R th1,c represents the thermal resistance between the bottom of the ferrite core 82 and the ceramic heat sink 78, C th,hs represents the heat capacity of the ceramic heat sink 78, R th,hs represents the thermal resistance between the ceramic heat sink 78 and the environment.

[0146] Fig.13A The component 73c of one embodiment of the present disclosure is illustrated, wherein the ceramic heat sink 78 is directly connected to the PCB Litz winding structure 74 and is separated from the ferrite core 82. In this embodiment, the ceramic heat sink 78 is directly connected to the winding structure (i.e., the heat source 76), so the winding can be effectively cooled. Fig.13A, the arrows used to represent the heat transfer paths are described in order from top to bottom as follows. Arrow 100 represents the primary heat transfer path starting from heat source 76, arrow 102 represents the secondary heat transfer path starting from heat source 76, and arrow 104 represents the primary heat transfer path starting from ferrite core 82. Component 73c is more suitable for situations where the total loss in the winding is greater than the loss of ferrite core 82, and where it is important or necessary to maintain the temperature of the winding within a reasonable range (compared to ferrite core 82). Since the ceramic heat sink 78 is directly connected to the winding structure and there is no other heat source that will transfer heat energy to the ceramic heat sink 78, the ceramic heat sink 78 can provide better thermal management for the winding structure.

[0147] Fig. 13B exemplify Fig.13A The thermal resistance network model 106 of the component 73c in FIG. The thermal resistance network model 106 includes several parameters, which are described one by one as follows. AT represents the ambient temperature, HS1 represents the heat source formed by the ferrite core 82, HS2 represents the heat source formed by the winding 76, C th0,w represents the thermal capacitance of the top of the PCB Litz winding structure 74, R th0,w represents the thermal resistance between the top of the PCB Litz winding structure 74 and the ceramic heat sink 78, C th1,w represents the thermal capacitance of the bottom of the PCB Litz winding structure 74, R th1,w represents the thermal resistance between the bottom of the PCB Litz winding structure 74 and the ferrite core 82, C th0,c represents the thermal capacitance of the top of the ferrite core 82, R th0,c represents the thermal resistance between the top of the ferrite core 82 and the PCB Litz winding structure 74, C th1,c represents the heat capacity of the bottom of the ferrite core 82, R th1,c represents the thermal resistance between the ferrite core 82 and the environment, C th,hs represents the heat capacity of the ceramic heat sink 78, R th,hs It represents the thermal resistance between the ceramic heat sink 78 and the environment. It can be seen from the thermal resistance network model 106 that the effective thermal resistance of the PCB Litz winding structure 74 is relatively low, so this embodiment is a better way to maintain the temperature of the winding structure within a reasonable range, but the premise is that the loss of the ferrite core 82 is not large.

[0148] Fig.14AComponent 73d of an embodiment of the present disclosure is illustrated, in which one ceramic heat sink 78a is directly connected to the side of the PCB Litz winding structure 74 away from the ferrite core 82; another ceramic heat sink 78b is connected to the other side of the PCB Litz winding structure 74 and is connected to the ferrite core 82. In other words, the ceramic heat sink 78b is arranged between the PCB Litz winding structure 74 and the ferrite core 82. In a sense, component 73d is an extension of component 73c. Fig.14A From the perspective of FIG. 1 , arrows used to represent heat transfer paths are described in order from top to bottom as follows: Arrows 108 and 110 represent the primary heat transfer path starting from the heat source 76, arrow 112 represents the primary heat transfer path starting from the ferrite core 82, and arrow 114 represents the secondary heat transfer path starting from the ferrite core 82.

[0149] Fig. 14B exemplify Fig.14A The thermal resistance network model 116 of the component 73d in FIG. The thermal resistance network model 106 includes several parameters, which are described below one by one. AT represents the ambient temperature, HS1 represents the heat source formed by the ferrite core 82, HS2 represents the heat source formed by the winding 76, C th0,c represents the heat capacity of the bottom of the ferrite core 82, R th0,c represents the thermal resistance between the bottom of the ferrite core 82 and the environment, C th0,w represents the thermal capacitance of the top of the PCB Litz winding structure 74, R th0,w represents the thermal resistance between the top of the PCB Litz winding structure 74 and the ceramic heat sink 78a, C th1,c represents the thermal capacitance of the top of the ferrite core 82, R th1,c represents the thermal resistance between the ferrite core 82 and the ceramic heat sink 78b, C th1,w represents the thermal capacitance of the bottom of the PCB Litz winding structure 74, R th1,w represents the thermal resistance between the bottom of the PCB Litz winding structure 74 and the ceramic heat sink 78b, C th,hs represents the heat capacity of the ceramic heat sink 78a, R th,hs represents the thermal resistance between the ceramic heat sink 78a and the environment.

[0150] Fig.15 An assembly 73e of an embodiment of the present disclosure is illustrated, wherein a PCB Litz winding structure 74 is sandwiched between ceramic heat sinks 78a and 78b (with Fig.14A 73d) and is directly connected to the ceramic heat sink. In the ceramic heat sink 78a, the side not adjacent to the PCB Litz winding structure 74 is connected to and adjacent to the ferrite core 82a; in the ceramic heat sink 78b, the side not adjacent to the PCB Litz winding structure 74 is connected to and adjacent to the ferrite core 82b. Fig.15, the arrows used to represent the heat transfer paths are described in order from top to bottom as follows. Arrow 118 represents the secondary heat transfer path starting from ferrite core 82a (top core), arrow 120 represents the primary heat transfer path starting from ferrite core 82a (top core), arrows 122 and 124 represent the primary heat transfer path starting from heat source 76, arrow 126 represents the primary heat transfer path starting from ferrite core 82b (bottom core), and arrow 128 represents the secondary heat transfer path starting from ferrite core 82b (bottom core). It should be noted that component 73e can be used in a conventional transformer structure. In this case, ferrite cores 82a and 82b are located on both sides of the winding structure and surround the winding structure. Ceramic heat sinks 78a and 78b can be used to dissipate heat from the winding structure from two directions, thereby providing better thermal management. In this structure, the ferrite cores 82 a and 82 b are also connected to the ceramic heat sinks 78 a and 78 b to help dissipate heat through the ceramic heat sink 78 .

[0151] Fig.16 Component 73f of an embodiment of the present disclosure is illustrated, wherein a PCB Litz winding structure 74 is sandwiched between ceramic heat sinks 78a and 78b and directly connected to ferrite cores 82a and 82b. In ferrite core 82a, a side not adjacent to the PCB Litz winding structure 74 is adjacent to and connected to ceramic heat sink 78a. In ferrite core 82b, a side not adjacent to the PCB Litz winding structure 74 is adjacent to and connected to ceramic heat sink 78b. Fig.16 From the perspective of FIG. 1 , arrows used to represent heat transfer paths are described in order from top to bottom as follows. Arrow 130 represents the main heat transfer path starting from ferrite core 82a (top core), arrow 132 represents the main heat transfer path starting from heat source 76, arrow 134 represents the main heat transfer path starting from heat source 76, and arrow 136 represents the secondary heat transfer path starting from ferrite core 82b (bottom core). In this embodiment, since ceramic heat sinks 78a and 78b are directly connected to ferrite cores 82a and 82b, the heat dissipation effect of ferrite cores 82a and 82b can be effectively improved. This structure is suitable for applications using a coupling transformer.

[0152] Fig.17 An assembly 73g of an embodiment of the present disclosure is illustrated, wherein the PCB Litz winding structure 74 is integrated into the ceramic heat sink 78 (e.g., a monolithic structure), and the ferrite core 82 is directly connected to and adjacent to the ceramic heat sink 78. Fig.17From the perspective of the heat source 76, the arrows used to represent the heat transfer paths are described in order from top to bottom as follows. Arrow 138 represents a secondary heat transfer path starting from the heat source 76, arrow 140 represents a primary heat transfer path starting from the heat source 76, arrow 142 represents a primary heat transfer path starting from the ferrite core 82, and arrow 144 represents a secondary heat transfer path starting from the ferrite core 82. In this structure, conventional FR4 materials can generally be used, or materials with higher thermal conductivity, such as KAPTON polyimide film, Mylar polyester film, or even a PCB with a ceramic substrate can be used. In this structure, a cooling pipe (as a fluid channel 80) can also be embedded to provide the cooling effect required for the PCB Leeds winding structure 74 and the ferrite core 82. Component 73g can be extended to be applied to FIG. 11A to FIG. 16 In the other structures shown.

[0153] The above describes multiple embodiments of systems and assemblies including PCB Litz winding or coil structures and ceramic heat sinks. Figure 3 , Figure 5A , Figure 5B as well as Figures 8 to 10 The wireless power transmission component 62 in the first embodiment of the present disclosure includes a flexible printed circuit board 66 and a ceramic heat sink 64. The flexible printed circuit board includes a Litz winding 68, wherein the Litz winding has a plurality of layers 32 of wires electrically isolated from each other. The ceramic heat sink is arranged corresponding to the flexible printed circuit board to dissipate heat from the flexible printed circuit board.

[0154] The illustrated first embodiment may include any one or more combinations of the following features.

[0155] In the wireless power transmission component of the first embodiment, the flexible printed circuit board includes a flexible insulating material, at least two layers of the plurality of layers are separated by the flexible insulating material, and the flexible insulating material located between the at least two layers has a minimum thickness, and the minimum thickness is between 1 mil and 10 mils.

[0156] In the wireless power transmission component of the first embodiment, the flexible insulating material is formed of polyester, adhesive polyamide or non-adhesive polyamide.

[0157] In the wireless power transmission device of the first embodiment, the Litz winding is formed of a bendable conductive material.

[0158] In the wireless power transmission device of the first embodiment, the Litz winding is formed of annealed copper.

[0159] In the wireless power transmission component of the first embodiment, the Litz winding is formed by a plurality of conductive wires that are electrically isolated from each other, and the plurality of conductive wires are connected in a spiral shape.

[0160] In the wireless power transmission device of the first embodiment, the conductive lines in the first layer 42 and the second layer 44 of the plurality of layers are connected via the through hole 50 .

[0161] In the wireless power transmission component of the first embodiment, the ceramic heat sink includes one or more fluid channels 70 .

[0162] In the wireless power transmission component of the first embodiment, the ceramic heat sink is in contact with the flexible printed circuit board, and the ceramic heat sink is adjacent to the flexible printed circuit board.

[0163] In the wireless power transmission component of the first embodiment, the ceramic heat sink includes a first ceramic heat sink and a second ceramic heat sink, the first ceramic heat sink and the second ceramic heat sink are in contact with the flexible printed circuit board, the first ceramic heat sink is adjacent to the first side of the flexible printed circuit board, and the second ceramic heat sink is adjacent to the second side of the flexible printed circuit board.

[0164] According to at least Figure 1A , Figure 3 , Figure 5A , Figure 5B as well as Figures 8 to 10 The wireless power transmission system 10 in the second embodiment illustrated in the present disclosure includes a transmitting unit or a receiving unit 12, wherein the transmitting unit or the receiving unit includes an input stage 15, a resonator 16 and a component 12. The component includes a flexible printed circuit board 66 and a ceramic heat sink 64. The flexible printed circuit board includes a Litz winding 68, wherein the Litz winding has a plurality of layers 32 of a plurality of conductors electrically isolated from each other. The ceramic heat sink is arranged corresponding to the flexible printed circuit board to dissipate heat from the flexible printed circuit board.

[0165] The illustrated second embodiment may include any one or more combinations of the following features.

[0166] In the wireless power transmission system of the second embodiment, the flexible printed circuit board includes a flexible insulating material 34, at least two layers 32a and 32b of the plurality of layers are separated by the flexible insulating material, and the flexible insulating material located between the at least two layers has a minimum thickness, and the minimum thickness is between 1 mil and 10 mils.

[0167] In the wireless power transmission system of the second embodiment, the flexible insulating material is formed of polyester, adhesive polyamide or non-adhesive polyamide.

[0168] In the wireless power transmission system of the second embodiment, the Litz winding is formed of a bendable conductive material.

[0169] In the wireless power transmission system of the second embodiment, the operating frequency of the components is in the range of 90 kHz to 200 kHz.

[0170] In the wireless power transmission system of the second embodiment, the Litz winding is formed by a plurality of conductive wires that are electrically isolated from each other, and the plurality of conductive wires are connected in a spiral shape.

[0171] In the wireless power transmission system of the second embodiment, the conductive lines in the first layer 42 and the second layer 44 of the plurality of layers are connected via the through-holes 50 .

[0172] In the wireless power transmission system of the second embodiment, the ceramic heat sink includes one or more fluid channels 70 .

[0173] In the wireless power transmission system of the second embodiment, the ceramic heat sink is in contact with the flexible printed circuit board, and the ceramic heat sink is disposed adjacent to the flexible printed circuit board.

[0174] In the wireless power transmission system of the second embodiment, the ceramic heat sink includes a first ceramic heat sink and a second ceramic heat sink. The first ceramic heat sink and the second ceramic heat sink are in contact with the flexible printed circuit board. The first ceramic heat sink is adjacent to a first side of the flexible printed circuit board, and the second ceramic heat sink is adjacent to a second side of the flexible printed circuit board.

[0175] It should be noted that the first embodiment and the second embodiment may also be combined with any of the aforementioned embodiments of the present disclosure.

[0176] It should be noted that the above are only preferred embodiments proposed for illustrating the present disclosure, and the present disclosure is not limited to the embodiments described. It should be understood that the present disclosure can have various changes in different implementations, all of which do not deviate from the scope of the present disclosure, and the description and illustrations of the present disclosure are essentially used for illustration rather than for limiting the present disclosure. The scope of the present disclosure is determined by the claims. And the present disclosure can be modified in various ways by those skilled in the art, all of which do not deviate from the protection intended by the claims.

Claims

1. A wireless power transmission component, comprising: A flexible printed circuit board comprising a Litz winding, wherein the Litz winding has a plurality of layers of conductors electrically isolated from each other; and A ceramic heat sink is arranged corresponding to the flexible printed circuit board to dissipate heat from the flexible printed circuit board.

2. The wireless power transmission component of claim 1 , wherein the flexible printed circuit board comprises a flexible insulating material, at least two of the plurality of layers are separated by the flexible insulating material, and the flexible insulating material between the at least two layers has a minimum thickness ranging from 1 mil to 10 mils. 3 . The wireless power transmission component as claimed in claim 2 , wherein the flexible insulating material is formed of polyester, adhesive polyamide or non-adhesive polyamide. The wireless power transmission component as claimed in claim 1 , wherein the Litz winding is formed of a bendable conductive material. The wireless power transmission component of claim 4 , wherein the Litz winding is formed of annealed copper. 6 . The wireless power transmission component as claimed in claim 1 , wherein the Litz winding is formed by the plurality of conductive wires electrically isolated from each other, and the plurality of conductive wires are connected in a spiral shape. 7 . The wireless power transmission component as claimed in claim 1 , wherein the conductive lines in a first layer and a second layer of the plurality of layers are connected via a through hole.

8. The wireless power transmission component as claimed in claim 1, wherein the ceramic heat sink comprises one or more fluid channels. 9 . The wireless power transmission component as claimed in claim 1 , wherein the ceramic heat sink is in contact with the flexible printed circuit board, and the ceramic heat sink is adjacent to the flexible printed circuit board.

10. The wireless power transmission component as described in claim 1, wherein the ceramic heat sink comprises a first ceramic heat sink and a second ceramic heat sink, the first ceramic heat sink and the second ceramic heat sink are in contact with the flexible printed circuit board, the first ceramic heat sink is adjacent to the first side of the flexible printed circuit board, and the second ceramic heat sink is adjacent to the second side of the flexible printed circuit board.

11. A wireless power transmission system, comprising: A transmitting unit or a receiving unit comprising an input stage, a resonator and a component, wherein the component comprises: A flexible printed circuit board comprising a Litz winding, wherein the Litz winding has a plurality of layers of conductors electrically isolated from each other; and A ceramic heat sink is arranged corresponding to the flexible printed circuit board to dissipate heat from the flexible printed circuit board.

12. The wireless power transmission system of claim 11 , wherein the flexible printed circuit board comprises a flexible insulating material, at least two of the plurality of layers are separated by the flexible insulating material, and the flexible insulating material between the at least two layers has a minimum thickness ranging from 1 mil to 10 mils. 13 . The wireless power transmission system as claimed in claim 12 , wherein the flexible insulating material is formed of polyester, adhesive polyamide or non-adhesive polyamide.

14. The wireless power transmission system of claim 11, wherein the Litz winding is formed of a bendable conductive material.

15. The wireless power transmission system of claim 11, wherein the operating frequency of the component is in the range of 90 kHz to 200 kHz. 16 . The wireless power transmission system as claimed in claim 11 , wherein the Litz winding is formed by the plurality of conductive wires that are electrically isolated from each other, and the plurality of conductive wires are connected in a spiral shape. 17 . The wireless power transmission system as claimed in claim 11 , wherein the conductive lines in a first layer and a second layer of the plurality of layers are connected via vias.

18. The wireless power transmission system of claim 11, wherein the ceramic heat sink comprises one or more fluid channels. 19 . The wireless power transmission system as claimed in claim 11 , wherein the ceramic heat sink is in contact with the flexible printed circuit board, and the ceramic heat sink is adjacent to the flexible printed circuit board.

20. The wireless power transmission system as claimed in claim 11, wherein the ceramic heat sink comprises a first ceramic heat sink and a second ceramic heat sink, the first ceramic heat sink and the second ceramic heat sink are in contact with the flexible printed circuit board, the first ceramic heat sink is adjacent to the first side of the flexible printed circuit board, and the second ceramic heat sink is adjacent to the second side of the flexible printed circuit board.

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