Wireless power transfer assembly and system

Abstract

This application provides a wireless power transmission component and system. The wireless power transmission component includes a flexible printed circuit board (PCB) and a ceramic heat sink. The PCB includes a Litz winding having multiple layers of electrically isolated conductors. The ceramic heat sink is disposed opposite the PCB to dissipate heat from the PCB.

Description

Technical Field

[0001] This case relates to a heat dissipation solution that can transfer the heat energy generated by a heat source (such as a winding or a power converter) to the environment, especially a component applicable to a printed circuit board winding structure for implementing this heat dissipation solution. Prior Art

[0002] With the development of wide-bandgap semiconductors, power devices capable of high-frequency switching, such as MOSFETs (metal-oxide-semiconductor field-effect transistors) and IGBTs (insulated gate bipolar transistors), have been gradually widely used in the industry. The use of these devices has opened up new application fields for high-frequency power conversion, including but not limited to electric vehicle charging infrastructure, renewable energy integration, active filters, and solid-state transformers.

[0003] Especially in the field of electric vehicle charging, WPT (wireless power transfer) has received a great deal of attention in recent years, especially in delivery trucks or other short-range transportation vehicles with preset driving routes. The increasing attention paid to wireless power transfer is at least partly due to its inherent advantages, such as reducing labor costs, programmability (which can be used to charge during off-peak hours), and, most importantly, operational safety during the charging process.

[0004] In wireless charging applications (such as electric vehicle charging), converters typically operate at high frequencies (e.g., around 100 kHz to 200 kHz). For high-power applications, the charging board can be manufactured using a traditional litz wire structure. For details, 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. Since the litz wire structure or litz wire has low losses when carrying high-frequency currents, it is usually favored in high-power applications. In high-power applications that require transmitting a large amount of high-frequency current, traditional litz wires are used to manufacture coils, and multiple coils are connected in parallel to achieve the required power. Although using litz wires can minimize AC losses as much as possible, the manufacturing process of the litz wire structure is difficult and not easy to scale up the power. For example, due to the difference in the coupling coefficient between each coil group, circulating current and / or significant inductive impedance mismatch 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, there are limitations in the winding method based on traditional litz wires. For example, as the size increases, the manufacturing of litz wires usually requires manual assembly, making large-scale production extremely cumbersome and difficult.

[0005] To address the problems faced by traditional litz wires, a PCB (printed circuit board)-based solution 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 there are certain power losses in the winding structure itself, the winding structure must be cooled to maintain the temperature of the winding within a reasonable range.

[0006] In addition, existing heat dissipation solutions also have some drawbacks. For example, coils or windings are usually cooled by natural air cooling or forced air cooling, which dissipate the heat energy generated by the winding structure by blowing air onto the winding structure or by utilizing natural air convection respectively. However, in applications where the coil carries a large current, the heat dissipation area of the coil itself may be insufficient to dissipate heat. In some methods, ferrite cores are used for heat dissipation. For example, ferrite cores are commonly used to form magnetic field lines, and ferrite cores are good heat conductors. However, the presence of the ferrite structure may impede the inflow of air into the coil, resulting in insufficient or ineffective natural or forced air cooling of the coil. In addition, in some methods, a metal heat sink can be provided between the PCB winding structure and the ferrite core, or a metal heat sink can be provided on the ferrite core, and the ferrite core is located between the PCB winding structure and the metal heat sink. Thereby, the heat sink is utilized to promote heat dissipation. In the latter case, a heat transfer path from the coil through the ferrite core to the heat sink can be formed. The setting of the 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 compared with the structure where the heat sink is located at the end of the heat transfer path, a lower thermal resistance and better heat dissipation ability can be provided. In addition, the direct connection between the ferrite core and the heat sink also helps with the heat dissipation of 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 provided metal heat sink may cause eddy currents, thereby generating additional current and losses, and further resulting in insufficient or ineffective cooling and a decrease in efficiency. SUMMARY OF THE INVENTION

[0007] An object of the present case is to provide a wireless power transmission component and system that can be used for electric vehicle charging.

[0008] According to one aspect of the present case, the 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 a plurality of electrically isolated conductors. The ceramic heat sink is provided corresponding to the flexible printed circuit board to dissipate heat from the flexible printed circuit board.

[0009] According to another aspect of the present case, the 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 components. The components include 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 a plurality of electrically isolated wires. The ceramic heat sink is disposed corresponding to the flexible printed circuit board to dissipate heat from the flexible printed circuit board.

[0010] Through the following embodiments, the foregoing aspects and other aspects of the invention of the present case can be easily understood. Brief Description of the Drawings

[0011] Through the following schematic diagrams, the embodiments of various aspects of the present case can be better understood. The elements in the drawings are not necessarily drawn to scale, and the emphasis is on clearly illustrating the principles of the embodiments of the present case. In addition, corresponding parts in these drawings are denoted by the same reference numerals.

[0012] FIG. 1A is a schematic structural diagram of a wireless power transmission system according to an embodiment of the present case.

[0013] FIG. 1B is a schematic circuit diagram of a part for performing wireless power transmission in the wireless power transmission system shown in FIG. 1A according to an embodiment of the present case.

[0014] FIG. 2 is a schematic diagram of a PCB Litz winding structure for the wireless power transmission part shown in FIG. 1A according to an embodiment of the present case.

[0015] FIG. 3 is a partial cross-sectional side view of a flexible PCB Litz winding structure simulating a non-PCB-based Litz winding method according to an embodiment of the present case.

[0016] FIG. 4A is a three-dimensional schematic diagram of a Litz winding layout of a flexible PCB Litz winding structure according to an embodiment of the present case.

[0017] FIG. 4B is a partial cross-sectional side view of a Litz winding layout of a flexible PCB Litz winding structure according to an embodiment of the present case.

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

[0019] Figure 5B is a perspective view of the double - layer flexible PCB Litz winding structure and the insulating material shown in Figure 5A in an embodiment of the present case.

[0020] Figure 6 is a waveform schematic diagram of the total losses of the rigid PCB Litz winding structure and the flexible PCB Litz winding structure in an embodiment of the present case under a current of 150 A and different frequencies.

[0021] Figure 7 is a waveform schematic diagram of the percentage of the loss reduction of the flexible PCB Litz winding structure compared with the rigid PCB Litz winding structure in an embodiment of the present case, which is based on the performance shown in Figure 6.

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

[0023] Figure 9 is a schematic structural diagram of a wireless power transmission component in an embodiment of the present case, where a ceramic heat sink is disposed on the flexible PCB Litz winding structure and is adjacent to the flexible PCB Litz winding structure.

[0024] Figure 10 is a schematic structural diagram of a wireless power transmission component in an embodiment of the present case, where the flexible PCB Litz winding structure is disposed between two ceramic heat sinks located above and below it and adjacent to it.

[0025] Figure 11A is a schematic structural diagram of a component in an embodiment of the present case, where a ceramic heat sink is located between the PCB Litz winding structure and the ferrite core.

[0026] Figure 11B illustrates the thermal resistance network model of the component in Figure 11A.

[0027] Figure 12A is a schematic structural diagram of a component in an embodiment of the present case, where the ceramic heat sink is separated from the PCB Litz winding structure and is connected to the ferrite core.

[0028] Figure 12B illustrates the thermal resistance network model of the component in Figure 12A.

[0029] Figure 13A is a schematic structural diagram of a component in an embodiment of the present case, where the ceramic heat sink is directly connected to the PCB Litz winding structure and is separated from the ferrite core.

[0030] Figure 13B illustrates the thermal resistance network model of the components in Figure 13A.

[0031] Figure 14A is a schematic structural diagram of a component according to an embodiment of the present case, wherein a 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] Figure 14B illustrates the thermal resistance network model of the components in Figure 14A.

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

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

[0035] Figure 17 is a schematic structural diagram of a component according to an embodiment of the present case, wherein the ceramic heat sink is integrated into the PCB Litz winding structure. Embodiments

[0036] Some embodiments of systems and components are disclosed in the present case, 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 components. In one embodiment, the component is used in a WPT system and includes a flexible PCB, wherein the WPT system can be used for electric vehicle charging, for example, and the flexible PCB includes a Litz winding or coil. The coil includes multiple layers of wires. In one embodiment, the wires can be configured as multiple electrically insulated conductive circuits, and the multiple conductive circuits are connected between the multiple layers to simulate a non-PCB-based Litz wire. For example, each of the multiple wires in one layer is an electrically insulated conductive circuit (such as an annealed copper circuit), and is serially connected between the multiple layers (such as through vias), thereby simulating the spiral or vortex pattern of a general Litz winding structure. In addition, the component further 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.

[0037] Existing PCB Litz windings can reduce high-frequency AC losses (compared to traditional copper conductors) by emulating (non-PCB-based) Litz wires, where the Litz windings are incorporated into the PCB structure and are segmented into multiple independent wires (e.g., each wire in a certain layer is serially connected to another wire in another layer using vias), and then these independent wires in multiple layers are woven in the same way as the traditional Litz wire structure. As described above, this structure emulates (non-PCB-based) Litz wires (and their characteristics) through the PCB without using traditional Litz wires. Compared to existing PCB structures, this way of emulating Litz wires on the PCB structure can help reduce AC losses. For more information on the PCB Litz winding structure, reference can be made to I. Lope, J. Acero, J. M. 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 the patent with U.S. Patent Publication No. 7,973,635 B2. One drawback of the existing structure is that each wire uses at least two layers of PCB to achieve the desired effect. Although this is an effective technique for reducing AC losses, since PCB insulating materials generally have a relatively low thermal conductivity (usually in the range of 0.3 W / mK to 0.6 W / mK) and are limited by the minimum interlayer thickness (e.g., about 10 mils), it is still difficult to dissipate heat from the inner layers of the PCB. Moreover, it is also very difficult to reduce the thickness of the dielectric layer because reducing the dielectric layer thickness increases the risk of cracks (which may thus affect reliability). Due to the thickness of the insulating materials commonly used in existing methods (such as FR4 materials), it will be difficult to dissipate the heat energy generated by the PCB windings, thereby making it difficult for the winding structure to operate at high power.

[0038] As can be seen from the foregoing, there are also some problems with existing heat dissipation solutions. For example, although metal heat sinks can provide good heat dissipation performance and are relatively easy to manufacture, due to their electrical conductivity, 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, electrical isolation cannot be provided. For applications that require electrical isolation, additional insulating materials may need to be provided between heat sources, which will increase the thermal resistance and reduce the heat dissipation performance. When extended to applications with higher power, these problems will become more serious.

[0039] In contrast, the present case provides some embodiments of systems and components including a PCB Litz winding structure and a ceramic heat sink, which combine the heat dissipation effects of a flexible PCB structure and a ceramic heat sink with a relatively small thickness to overcome the heat dissipation problems faced when using existing PCB structures, and at the same time can provide electrical isolation that existing metal heat sinks do not have.

[0040] After summarizing the characteristics of the components (including the PCB winding structure and the ceramic heat sink) proposed in the present case, the components in the drawings will now be described in detail. Although the following will be described in conjunction with the drawings and focus on the Litz winding structure and the 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 case is not limited to the illustrated embodiments. For example, in some embodiments, the PCB-based Litz winding assembly may also use a rigid PCB Litz winding structure and a ceramic heat sink. For example, the rigid PCB Litz winding assembly may include a magnetic core (such as a ferrite core) for wired applications. In addition, although specific features of certain embodiments are mentioned or described in the description, these specific features may not be 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 equivalent solutions within the principles and scope defined in the appended patent claims. For example, two or more embodiments may be interchanged or combined in any combination. Furthermore, it should be understood that the patent claims of the present case are not limited to the embodiments illustrated in the description.

[0041] In the following description, unless otherwise specifically defined, the described 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 (such as a Litz wire used in a non-PCB implementation aspect) and a Litz winding or coil disposed on the PCB. The "wire" and "winding" in this article correspond to the existing non-PCB-based Litz winding method, while the "coil", "winding", and "winding structure" correspond to the PCB winding arrangement that simulates the configuration and function of the non-PCB-based Litz wire. Although the ceramic heat sink is not shown in some diagrams of different components, it should be understood that the ceramic heat sink can be expected to be used in any of the shown PCB Litz winding structures.

[0042] In addition, it should be noted that the terms "coil", "winding", "winding structure", and similar terms can be used interchangeably in the description of this case.

[0043] As described above, some embodiments of components (such as WPT components) are proposed in this case, in which the components combine the heat dissipation advantages of a flexible PCB structure and a ceramic heat sink correspondingly arranged therewith. For example, the flexible PCB Litz winding structure can be used for power transmission, has low loss and good thermal conductivity, and is easier to manufacture compared with the existing rigid PCB Litz winding design or non-PCB-based Litz wire design. 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 with a larger current. In addition, the heat dissipation solution provided by the ceramic heat sink can effectively conduct heat energy from heat sources (such as windings and / or ferrite cores, and even heat sources in other components close to the component (such as adjacent or temporarily close)), and 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 with a metal heat sink. Specifically, the ceramic heat sink can be in direct contact with the winding (such as abutting the winding against the ceramic heat sink, and a thermal conductive adhesive can be used), without the need for insulation (that is, there is no insulation or air gap between the winding and the ceramic heat sink), thus 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.

[0044] FIG. 1A is a schematic diagram of the architecture of a wireless power transfer (WPT) system 10 according to an embodiment of the present invention. The wireless power transfer system 10 is applicable to electric vehicle charging and other applications involving wireless power transfer, especially high-power and high-frequency applications. The wireless power transfer 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) for charging an electric vehicle or a charging board (such as a charging board located in a residential garage). The receiving unit 14 can be disposed inside the electric vehicle. In the illustrated embodiment, the transmitting unit 12 includes an input stage 15 and a resonator 16.

[0045] 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 functions of performing AC / DC, DC / DC, and DC / AC conversions. For example, an AC / DC converter can be used to convert the AC input electrical energy into a fixed DC intermediate electrical energy (such as 800 V), and then the fixed DC intermediate electrical energy can be converted into a variable DC intermediate electrical energy (such as 0 V to 800 V) through a DC / DC converter, and then the variable DC intermediate electrical energy is input to an inverter (such as including a plurality of switches for controlling the duty cycle and frequency). In some embodiments, the DC / DC conversion process can be omitted.

[0046] The resonator 16 includes a tuning circuit (such as including a resistor, a capacitor, and a PCB coil connected in series). By applying AC electrical energy to the input of the resonator 16, the resonator 16 starts to oscillate to generate a magnetic field in the space around the resonator 16. In some cases, a ferrite core (such as in non-WPT applications) can be used to direct the magnetic field direction according to specific application requirements.

[0047] 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 properly placing the resonator 17 within 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.

[0048] 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 electric energy to a specific load (such as charging an electric vehicle battery). For example, the output stage 18 may include an AC / DC converter connected to the output terminal of the resonator 17, where the AC / DC converter converts the AC electric energy received at its input terminal into DC output electric energy. The AC / DC converter may include a synchronous rectifier, a bulk capacitor, and an output filter, where the bulk capacitor and the output filter are connected after the synchronous rectifier and are used to shape the DC output electric energy.

[0049] The controller 19 controls the power transmission from the transmitting unit 12 through the air gap to the receiving unit 14, and controls the electric energy provided to the load connected to the output stage 18, such as meeting the requirements of a specific application (meeting the specific output electric energy 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 an electric energy set value from the load (such as a current set value from the battery management system of the load battery). The controller 19 (or another controller communicating 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 use the sensed current (and the current set value) to generate a control signal to control the transmitting unit 12 through the control signal (such as for generating a magnetic field that meets the required output electric energy).

[0050] The transmitting unit 12 and the receiving unit 14 may also include other functions, such as including a communication interface (not shown), which can facilitate the cooperation between various systems and devices (such as the cooperation between the battery management system and the wireless power transmission system 10 in a charging application). It should be noted that the circuits of the transmitting unit 12 and the receiving unit 14 may use digital, analog, or mixed-signal electronic devices, and can be specifically implemented through 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 elaborated here.

[0051] It should be noted that in some embodiments, the functions of the input stage 15 and the resonator 16 may be integrated in a single PCB or distributed in multiple PCB structures. Similarly, the functions of the output stage 18 and the resonator 17 may also be integrated in a single PCB or distributed in multiple PCB structures.

[0052] Figure 1B illustrates the circuit structure of the wireless power transmission system 10 in Figure 1A, and focuses on the wireless power transmission coil system 20, which schematically represents the resonators 16 and 17 by 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 that propagates in the air and passes through the receiving unit coil, thereby generating a current in the receiving unit coil, and finally using this electricity to charge the electric vehicle.

[0053] Figure 2 illustrates a flexible PCB litz winding structure 20a, which is applicable to wireless power transmission. For example, it can achieve the functions required by the wireless power transmission coil system 20 in Figure 1B, especially for the transmitting-side PCB coil of the resonator 16, but the following description also applies to the receiving-side PCB coil of the resonator 17. In this example, the flexible PCB litz winding structure 20a includes a flexible PCB, and the flexible PCB includes a litz winding 22. The litz winding 22 includes a plurality of conductors or lines (for example, lines with a plurality of series connections and electrically insulated from each other), and the plurality of conductors or lines can be arranged in multiple layers to simulate a non-PCB-based litz wire, which will be described in detail later. In addition, although the litz winding 22 in this example has a circular geometric structure, in some embodiments, the litz winding 22 can also be configured in other shapes (such as rectangular).

[0054] FIG. 3 shows an embodiment of the flexible PCB Litz winding structure 28. The flexible PCB Litz winding structure 28 includes a Litz winding 30 that emulates a Litz wire (not based on a PCB). The flexible PCB Litz winding structure 28 can be the same as or similar to the flexible PCB Litz winding structure 20a shown in FIG. 2. In this embodiment, the Litz winding 30 has multiple layers, such as layers 32a, 32b, 32c, and 32d (collectively referred to as layer 32). Although four layers are shown in the figure, in practice, other numbers of layers can also be used, such as two to fifteen layers, but it is not limited to this range. Briefly, although the more layers there are, 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 fifteen-layer structure can provide excellent performance, but it is more difficult to manufacture (and thus more costly) compared to a structure with fewer layers, and in fact, such a multi-layer structure may not be needed in low-cost applications. Each layer 32 is electrically insulated by a flexible insulating layer 34. In one embodiment, the distance between adjacent layers 32 (or equivalently, the thickness of the flexible insulating layer 34 between the layers) is about 1 mil to 10 mils. In addition, the distance between the outermost layer 32 and the edge of the flexible PCB Litz winding structure 28 (or the thickness of the flexible insulating layer 34 between the outermost 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 being the same 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 the PCB structural material), can be formed of polyester, adhesive polyamide, or non-adhesive polyamide, and other flexible insulating materials can also be used in other embodiments. The insulating material used depends on the actual application requirements. In contrast, a rigid PCB Litz winding structure is usually made of different types of polyamide (such as FR4), and since it is rigid, it is prone to breakage when bent. For example, for the same radius of bending, a rigid PCB is more likely to break than a 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 in the case of an increasing number of layers. In addition, the thickness of the rigid PCB Litz winding structure makes heat dissipation difficult, especially for the inner layers. In contrast, the flexible PCB Litz winding structure 28 can provide a better heat conduction path due to its smaller insulating material thickness and can dissipate more heat energy than the rigid PCB Litz winding structure. The Litz winding 30 is also made of a flexible conductive material and can include a metal conductive material (such as bendable annealed copper) or a non-metal conductive material (such as made of graphene material).

[0055] FIG. 4A and FIG. 4B illustrate a Litz winding layout 36 of a flexible PCB Litz winding structure (such as the flexible PCB Litz winding structure 28 in FIG. 3 or the flexible PCB Litz winding structure 20a in FIG. 2). The Litz winding layout 36 provides a technique for reducing high-frequency AC losses by splitting the conductors (such as copper conductors) in the flexible PCB Litz winding structure into multiple independent wires or traces, thereby simulating an existing Litz wire structure, where the multiple wires or traces can be collectively referred to as a wire bundle. It should be noted that each wire includes a continuous conductive trace that can be serially connected to another wire using a via. Referring to FIG. 4A, in this example, three wires form a wire bundle (or a coil), where each wire is electrically isolated from the others (e.g., isolation is achieved through an insulating material located between the wires in the PCB structure). Along the path of one of the wires 38 in FIG. 4A from left to right, it can be seen that this is a spiral winding layout, where the wire 38 starts from one layer (the first layer), extends at an angle, or in other words, spans the width of the wire bundle along the plane of the first layer. Then, after spanning the width of the wire bundle and reaching a via (not shown), the via enables the wire 38 to continue extending on another layer. When the wire 38 again spans the width of the wire bundle along the second plane and reaches a second via, the second via enables the wire 38 to return to the top layer or the initial layer. Thus, the first section can be understood as the length of the wire 38 along the first layer in one direction, the second section can be understood as the length of the wire 38 along the second layer in the other direction, and the first section and the second section are serially connected to each other via the via. The other wires in the wire bundle can also be arranged in a similar manner. Thereby, the wire 38 (and the other wires as well) is arranged in a spiral shape, so it can simulate an existing Litz wire both structurally and functionally. Since each wire passes through a specific position in the wire bundle, all the wires or windings are spatially equivalent. As shown in FIG. 4B, it shows the induced voltage (+V) generated between a pair of wires or traces. 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.

[0056] FIG. 5A illustrates a double - layer flexible PCB Litz winding structure 40, which simulates Litz wires wound in a spiral shape. The double - layer flexible PCB Litz winding structure 40 can be used for (or extended to) any flexible PCB Litz winding structure described above (or hereinafter). The double - layer flexible PCB Litz winding structure 40 includes conductors or traces on a first layer 42, conductors or traces on a second layer 44, and a flexible insulating layer (illustrated in FIG. 5B) between the first layer 42 and the second layer 44. In this example, there are five mutually electrically isolated conductors (isolated, for example, by insulating material located between the conductors, not shown in FIG. 5A), and the path of one conductor 46 is depicted by a thick line 48 to show the spiral winding structure of the conductor. It should be noted that fewer or more conductors may be used in some embodiments. Similar to the Litz winding layout 36 in FIGS. 4A and 4B described above, the conductor 46 (as shown by the thick line 48) spans the width of the wire bundle on the first layer 42 until it reaches a via 50 (the via 50 is covered by the thick line 48, but its structure is similar to other vias in FIG. 5A). The via 50 forms an electrical connection (such as a series connection) between the first layer 42 and the second layer 44. In this example, the via 50 enables the conductor 46 to effectively (electrically) extend to the second layer 44 and continue to extend along the path shown by the thick line 48 (for example, extend to another via), and then connect back to the first layer 42 (for example, through a via) and repeat the winding accordingly. As described above, the first layer 42, the second layer 44, and the conductors in the layers are mutually electrically isolated by insulating material located between them, such as the insulating material 52 of the double - layer flexible PCB Litz winding structure 40a shown in FIG. 5B, where the double - layer flexible PCB Litz winding structures 40a and 40 are similar, except that the insulating material 52 is further shown in the double - layer flexible PCB Litz winding structure 40a in FIG. 5B. As previously mentioned, the thickness of the insulating material 52 is approximately between 1 mil and 10 mils to effectively dissipate heat from a heat source (such as a coil). It should be noted that although FIGS. 5A and 5B show multiple conductors with a single turn on each layer, in other embodiments, there may be more turns. For example, the conductors shown in FIGS. 5A and 5B can be replicated to achieve a double - turn winding, such as adding a set of adjacent conductors along the x - direction to the conductors shown in the figure in each layer. In addition, more layers of conductors (such as adding along the y - direction) and / or different numbers of conductors in each layer can also be provided.

[0057] It should also be noted 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, the current distribution can be observed to be inconsistent, which in turn leads to different losses in each layer and an increase in the total loss. The degree of influence 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 relatively high 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 loss in the winding is lower at the same current amplitude and frequency.

[0058] Figure 6 shows a waveform diagram 54, where the waveform diagram 54 illustrates the total losses of a rigid PCB Litz winding structure and a flexible PCB Litz winding structure at a current of 150 A and different frequencies. In waveform diagram 54, the vertical axis represents the AC loss (watts), and the horizontal axis represents the frequency (kilohertz). For example, the rigid PCB Litz winding structure consists of a total of eight layers and four turns, and each winding path can be split into twelve conductors evenly distributed on two layers, thus forming an intertwined Litz winding structure. The distance between each layer is maintained at 10 mils, which is the minimum interlayer distance achievable in a rigid PCB Litz winding structure. However, in a flexible PCB Litz winding structure with the same number of wires and layers, the distance between each layer can be reduced to 1 mil. When the current flowing through the winding is 150 A and the frequency ranges from 0 hertz (DC) to 600 kilohertz, the total loss of the exemplified rigid PCB Litz winding structure is represented by curve 56, and the total loss of the exemplified flexible PCB Litz winding structure is represented by curve 58. It can be observed that the losses of the two structures are the same 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 generally mean lower heat dissipation requirements, the design considerations can include achieving a balance between heat dissipation in the internal winding (such as in the tenth to fifteenth layers) and reducing AC losses.

[0059] Figure 7 shows a waveform diagram 60 based on the performance shown in Figure 6. In waveform diagram 60, the vertical axis represents the efficiency (percentage), and the horizontal axis represents the frequency (kilohertz). Based on the performance shown in Figure 6, 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 kilohertz, it can reduce about half of the losses compared to the rigid PCB Litz winding structure. Therefore, within this frequency range, the flexible PCB Litz winding structure operates more ideally.

[0060] After describing some differences between the flexible PCB Litz winding structure and the rigid PCB Litz winding structure, some embodiments of a wireless power transfer component will be illustrated in FIGS. 8 to 10, wherein the wireless power transfer component incorporates a flexible PCB Litz winding structure and a ceramic heat sink (also referred to as a cooling plate). The WPT components illustrated in FIGS. 8 to 10 can be applicable to a WPT system (such as the WPT system 10 in FIG. 1A). The components illustrated in FIGS. 8 to 10 are particularly applicable to wireless power transfer in an electric vehicle charging application. In the subsequent description, the various flexible PCB Litz winding structures mentioned previously can be part of the components shown in FIGS. 8 to 10. The components shown can be combined in any form in a wireless power transfer system. For example, the component shown in FIG. 8 can be used in a transmitting unit, while the components shown in FIG. 9 or FIG. 10 can be used in a receiving unit, and vice versa. In addition, FIGS. 11A to 17 illustrate various rigid PCB Litz winding structures for non-wireless applications, wherein the heat source includes a ferrite core in addition to the Litz winding.

[0061] Digressing slightly, a ceramic heat sink can be provided as a heat dissipation solution for efficiently导出 heat energy from a heat source, where the heat source is, for example, a litz wire winding (in an application 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 can be other components co-located with an emission unit (such as emission unit 12 in FIG. 1A) that includes a flexible PCB litz winding structure, such as components located on another PCB (such as a circuit with an input stage 15), or components that are temporarily close to the flexible PCB litz winding structure (such as components of a receiving unit on a vehicle driving into a charging station where the emission unit is installed). In such cases, the ceramic heat sink can be used to导出 the heat energy generated by the heat source, where the ceramic heat sink can be made of various ceramic materials, and in some embodiments, the ceramic heat sink can be manufactured to have one or more channels (such as pipes, conduits, and delivery tubes, etc.) for fluid flow inside, to promote the heat dissipation effect through fluid flow (such as flowing under a controllable pressure or relying on gravity). The position of the ceramic heat sink can be adjusted according to design requirements. Compared with a metal heat sink, the ceramic heat sink can provide the required insulation effect while enhancing heat dissipation. For example, unlike a metal heat sink, the ceramic heat sink is electrically insulating, so the magnetic field generated by the winding will not cause additional losses on the ceramic heat sink. Therefore, the ceramic heat sink substantially does not generate eddy current losses. According to the thermal model of at least some of the shown components, the heat energy from the heat source (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 path for the heat transfer route, helping to keep the temperature of the heat source within the normal range. In fact, by appropriately arranging the ceramic heat sink corresponding to the litz winding, a better heat dissipation effect 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.

[0062] It should be noted that the Chinese character "导出" in the original text seems to be an incorrect or incomplete expression. I have translated it as "导出" as it is, but it might need to be corrected to a more accurate term in the actual context. Also, for better readability and understanding, it is recommended to review and clarify the technical content and language in the original text.First, the following will be described by taking the wireless power transmission component for electric vehicle charging as an example and in conjunction with FIGS. 8 to 10. FIG. 8 illustrates the wireless power transmission component 62a of an embodiment of the present case, where the ceramic heat sink 64 is disposed under (beneath and / or connected or in contact with) the flexible PCB litz winding structure 66 and is adjacent to the flexible PCB litz winding structure 66 (which may also be referred to by similar names such as flexible PCB structure, flexible PCB, etc.), and the flexible PCB litz winding structure 66 includes a heat source (such as 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 through screws or other fixing mechanisms. The flexible PCB litz winding structure 66 includes materials with flexibility and insulation properties (such as the flexible insulating layer 34 in FIG. 3 or the flexible insulating material 52 in FIG. 5B), which include the structural materials of the PCB. In the illustrated embodiment, the ceramic heat sink 64 further includes fluid channels 70, and the fluid channels 70 contribute to dissipating heat from the heat source 68. The coolant may be water or ethylene glycol, for example. The number or arrangement of the fluid channels 70 may be different from the example in FIG. 8 (and may also be similar to or different from the examples in FIGS. 9 to 17). In some other embodiments, the fluid channels 70 may also 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 a litz winding) to the ceramic heat sink 64.

[0063] FIG. 9 illustrates the wireless power transmission component 62b of another embodiment of the present case, where the ceramic heat sink 64 (including the fluid channels 70) is disposed on the flexible PCB litz winding structure 66 and is adjacent to the flexible PCB litz winding structure 66. Similar to the description for FIG. 8, in some embodiments, the fluid channels in the wireless power transmission component (or other components in FIGS. 11A to 17) may be omitted. The arrow 72 also represents the heat transfer path. In this embodiment, the heat transfer path is from the heat source 68 (such as a litz winding) to the ceramic heat sink 64.

[0064] FIG. 10 illustrates yet another embodiment of the wireless power transmission component (or system) 62c of the present case. The flexible PCB litz winding structure 66 is disposed between two ceramic heat sinks that are located above and below it and adjacent to it. In this embodiment, the two ceramic heat sinks include ceramic heat sinks 64a and 64b, and the ceramic heat sinks 64a and 64b respectively include fluid channels 70a and 70b. The coolant may be provided from a single source and dispersed into the corresponding fluid channels 70a and 70b (such as by using a valve), or the fluid channels 70a and 70b each have a separate coolant source. The two arrows 72 respectively represent the heat transfer paths from the heat source 68 (such as a litz wire) to the ceramic heat sinks 64a and 64b.

[0065] According to actual design requirements, the radio power transmission system may adopt the same or different embodiments shown in FIGS. 8 to 10 for the transmitting unit and / or the receiving unit. In addition, the ceramic heat sink 64 can not only dissipate heat for the radio power transmission components (such as the radio power transmission component 62a, the radio power transmission component 62b, and / or the radio power transmission component 62c), but also dissipate heat for other components. For example, the ceramic heat sink 64 is also used to transfer the heat energy generated by the power converter or adjacent electronic components in the electric vehicle.

[0066] As previously described, in the embodiments of this case, 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 radio power transmission applications. FIGS. 11A to 17 illustrate embodiments of systems or components using a rigid PCB Litz winding structure in various wired applications, where the wired applications involve power transmission and include ferrite cores. It should be noted that the described "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, for example, by screws or clamps, and a thermally conductive and electrically conductive material can be optionally used.

[0067] FIG. 11A shows a component 73a of an embodiment of this case, where the ceramic heat sink 78 is located between the PCB Litz winding structure 74 and the ferrite core 82 (the ferrite core 82 is marked by a dashed line). For example, the ceramic heat sink 78 can be connected to the ferrite core 82 through screws or clamps, and a heat dissipation medium material can be used between the ferrite core 82 and the ceramic heat sink 78 to improve the thermal conductivity (i.e., heat transfer). Similar to the previous description for radio power transmission applications and applicable to the components shown in FIGS. 12A to 17, the PCB Litz winding structure 74 includes a heat source 76, where 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 like FR4). In one embodiment, the ceramic heat sink 78 includes one or more fluid channels, such as one fluid channel 80 shown in the figure. In other embodiments, the fluid channels in the ceramic heat sinks in FIGS. 11A to 17 can also be omitted.

[0068] Also shown in FIG. 11A are several arrows 84, 86, 88, and 90 representing heat transfer paths. From top to bottom in the perspective of looking directly at FIG. 11A, arrow 84 represents a secondary heat transfer path (starting from heat source 76), arrow 86 represents the main heat transfer path from heat source 76 to the ceramic heat sink 78, arrow 88 represents the main heat transfer path from the ferrite core 82 to the ceramic heat sink 78, and arrow 90 represents the secondary heat transfer path from the ferrite core 82 to the surrounding environment (air). Similar to the description for FIG. 8, component 73a provides a heat dissipation solution. Different from a metal heat sink, since the ceramic heat sink 78 is electrically insulating, 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 substantially generate eddy current losses. As shown in the thermal model of component 73a (see FIG. 11B), the thermal energy from two heat sources (including heat source 76 related to 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 path for the heat transfer path, which helps to keep the temperature of the heat source within the normal range.

[0069] FIG. 11B illustrates the thermal resistance network model 92 of component 73a in FIG. 11A. The thermal resistance network model 92 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 76 formed by the winding, Cth0,c represents the heat capacity at the bottom of the ferrite core 82, Rth0,c represents the thermal resistance between the bottom of the ferrite core 82 and the environment, Cth0,w represents the heat capacity at the top of the PCB Litz winding structure 74, Rth0,w represents the thermal resistance between the top of the PCB Litz winding structure 74 and the environment, Cth1,c represents the heat capacity at the top of the ferrite core 82, Rth1,c represents the thermal resistance between the top of the ferrite core 82 and the ceramic heat sink 78, Cth1,w represents the heat capacity at the bottom of the PCB Litz winding structure 74, Rth1,w represents the thermal resistance between the bottom of the PCB Litz winding structure 74 and the ceramic heat sink 78, Cth,hs represents the heat capacity of the ceramic heat sink 78, and Rth,hs represents the thermal resistance between the ceramic heat sink 78 and the environment. As described above, different from a metal heat sink, the ceramic heat sink 78 is electrically insulating, so there are no eddy current losses on the ceramic heat sink 78. Therefore, the heat source related to the heat sink can be omitted in the thermal resistance network model 92.

[0070] FIG. 12A illustrates the component 73b of an embodiment of the present case, where the ceramic heat sink 78 is separated from the PCB litz winding structure 74 and is 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. From the perspective of looking directly at FIG. 12A, the arrows used to represent the heat transfer paths are described as follows from top to bottom. Arrow 94 represents the secondary heat transfer path starting 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. 12B), the thermal energy originating from the heat source 76 reaches the ceramic heat sink 78 via the ferrite core 82 (which itself has a certain thermal resistance).

[0071] FIG. 12B illustrates the thermal resistance network model 99 of the component 73b in FIG. 12A. The thermal resistance network model 99 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 76 formed by the winding, C th0,w represents the heat capacity 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 ambient, C th1,w represents the heat capacity 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 heat capacity 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, and R th,hs represents the thermal resistance between the ceramic heat sink 78 and the ambient.

[0072] Figure 13A illustrates component 73c of an embodiment of the present case, where 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., heat source 76), so the winding can be effectively cooled. From the perspective of looking directly at Figure 13A, the arrows used to represent the heat transfer path are described in sequence from top to bottom as follows. Arrow 100 represents the main heat transfer path starting from the heat source 76, arrow 102 represents the secondary heat transfer path starting from the heat source 76, and arrow 104 represents the main heat transfer path starting from the ferrite core 82. Component 73c is more suitable for situations where the total loss in the winding is greater than the loss of the ferrite core 82, and situations where it is emphasized or necessary to maintain the temperature of the winding within a reasonable range (compared to the 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 heat energy management for the winding structure.

[0073] Figure 13B illustrates the thermal resistance network model 106 of component 73c in Figure 13A. 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 76 formed by the winding, Cth0,w represents the heat capacity of the top of the PCB litz winding structure 74, Rth0,w represents the thermal resistance between the top of the PCB litz winding structure 74 and the ceramic heat sink 78, Cth1,w represents the heat capacity of the bottom of the PCB litz winding structure 74, Rth1,w represents the thermal resistance between the bottom of the PCB litz winding structure 74 and the ferrite core 82, Cth0,c represents the heat capacity of the top of the ferrite core 82, Rth0,c represents the thermal resistance between the top of the ferrite core 82 and the PCB litz winding structure 74, Cth1,c represents the heat capacity of the bottom of the ferrite core 82, Rth1,c represents the thermal resistance between the ferrite core 82 and the environment, Cth,hs represents the heat capacity of the ceramic heat sink 78, and Rth,hs 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 based on the relatively low effective thermal resistance of the PCB litz winding structure 74, this embodiment is a better method for maintaining the temperature of the winding structure within a reasonable range, provided that the loss of the ferrite core 82 is not large.

[0074] FIG. 14A illustrates component 73d of an embodiment of the present case, where a ceramic heat sink 78a is directly connected to one 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 disposed between the PCB litz winding structure 74 and the ferrite core 82. In a sense, component 73d is an extension of component 73c. From the perspective of looking directly at FIG. 14A, the arrows used to represent the heat transfer paths are described as follows from top to bottom in sequence. Arrows 108 and 110 represent the main heat transfer paths starting from the heat source 76, arrow 112 represents the main heat transfer path starting from the ferrite core 82, and arrow 114 represents the secondary heat transfer path starting from the ferrite core 82.

[0075] FIG. 14B illustrates the thermal resistance network model 116 of component 73d in FIG. 14A. 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 76 formed by the winding, Cth0,c represents the heat capacity of the bottom of the ferrite core 82, Rth0,c represents the thermal resistance between the bottom of the ferrite core 82 and the environment, Cth0,w represents the heat capacity of the top of the PCB litz winding structure 74, Rth0,w represents the thermal resistance between the top of the PCB litz winding structure 74 and the ceramic heat sink 78a, Cth1,c represents the heat capacity of the top of the ferrite core 82, Rth1,c represents the thermal resistance between the ferrite core 82 and the ceramic heat sink 78b, Cth1,w represents the heat capacity of the bottom of the PCB litz winding structure 74, Rth1,w represents the thermal resistance between the bottom of the PCB litz winding structure 74 and the ceramic heat sink 78b, Cth,hs represents the heat capacity of the ceramic heat sink 78a, and Rth,hs represents the thermal resistance between the ceramic heat sink 78a and the environment.

[0076] FIG. 15 illustrates component 73e of an embodiment of the present case, where the PCB Litz winding structure 74 is sandwiched between ceramic heat sinks 78a and 78b (similar to component 73d in FIG. 14A), and is directly connected to the ceramic heat sinks. In ceramic heat sink 78a, one side not adjacent to the PCB Litz winding structure 74 is connected and adjacent to ferrite core 82a; in ceramic heat sink 78b, one side not adjacent to the PCB Litz winding structure 74 is connected and adjacent to ferrite core 82b. From the perspective of looking directly at 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 respectively represent the primary heat transfer paths 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 traditional 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 two directions for the winding structure, thereby providing better thermal management. In this structure, ferrite cores 82a and 82b are also connected to ceramic heat sinks 78a and 78b, which helps to dissipate heat through ceramic heat sink 78.

[0077] FIG. 16 illustrates component 73f of an embodiment of the present case, where the PCB Litz winding structure 74 is sandwiched between ceramic heat sinks 78a and 78b, and is directly connected to ferrite cores 82a and 82b. In ferrite core 82a, one side not adjacent to the PCB Litz winding structure 74 is adjacent to and connected to ceramic heat sink 78a. In ferrite core 82b, one side not adjacent to the PCB Litz winding structure 74 is adjacent to and connected to ceramic heat sink 78b. From the perspective of looking directly at FIG. 16, the arrows used to represent the heat transfer paths are described in order from top to bottom as follows. Arrow 130 represents the primary heat transfer path starting from ferrite core 82a (top core), arrow 132 represents the primary heat transfer path starting from heat source 76, arrow 134 represents the primary 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 on ferrite cores 82a and 82b can be effectively improved. This structure is applicable to applications using coupled transformers.

[0078] Figure 17 illustrates component 73g of an embodiment of the present case, where the PCB Litz winding structure 74 is integrated in a ceramic heat sink 78 (e.g., a single-piece structure), and the ferrite core 82 is directly connected and adjacent to the ceramic heat sink 78. From the perspective of looking directly at Figure 17, the arrows used to represent the heat transfer paths are described in sequence 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, traditional FR4 materials can generally be used, or materials with higher thermal conductivity can be used, such as KAPTON polyimide film, Mylar polyester film, or even a ceramic substrate-based PCB. In this structure, cooling tubes (as fluid channels 80) can also be embedded to provide the cooling effect required for the PCB Litz winding structure 74 and the ferrite core 82. Component 73g can be extended and applied to other structures shown in Figures 11A to 16.

[0079] The above description includes multiple embodiments of systems and components including PCB Litz windings or coil structures and ceramic heat sinks. According to at least Figures 3, 5A, 5B, and 8 to 10 of the present case, the wireless power transfer components (62a, 62b, 62c) in the first embodiment illustrated in the present case include a flexible printed circuit board (66) and a ceramic heat sink (64). The flexible printed circuit board includes a Litz winding (68), where the Litz winding has a plurality of layers (32) of a plurality of electrically isolated conductors. The ceramic heat sink is arranged corresponding to the flexible printed circuit board to dissipate heat from the flexible printed circuit board.

[0080] The first embodiment illustrated may include any one or a combination of more than one of the following features.

[0081] In the wireless power transfer component of the first embodiment, the flexible printed circuit board includes a flexible insulating material. At least two of the plurality of layers are separated by the flexible insulating material, and the flexible insulating material located between at least two layers has a minimum thickness, and the minimum thickness ranges from 1 mil to 10 mils.

[0082] In the wireless power transfer component of the first embodiment, the flexible insulating material is formed of polyester, viscous polyamide, or non-viscous polyamide.

[0083] In the wireless power transfer component of the first embodiment, the Litz winding is formed of a bendable conductive material.

[0084] In the wireless power transmission component of the first embodiment, the Litz winding is formed of annealed copper.

[0085] In the wireless power transmission component of the first embodiment, the Litz winding is formed of a plurality of wires that are electrically isolated from each other, and the plurality of wires are connected in a spiral shape.

[0086] In the wireless power transmission component of the first embodiment, the wires in the first layer (42) and the second layer (44) of the plurality of layers are connected via vias (50).

[0087] In the wireless power transmission component of the first embodiment, the ceramic heat sink includes one or more fluid channels (70).

[0088] 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.

[0089] 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.

[0090] According to at least FIGS. 1A, 3, 5A, 5B, and 8 to 10 of the present case, the wireless power transmission system (10) in the second embodiment illustrated in the present case includes a transmitting unit (12) or a receiving unit, wherein the transmitting unit or the receiving unit includes an input stage (15), a resonator (16), and components (62a, 62b, 62c). The components include 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 wires that are electrically isolated from each other. The ceramic heat sink is disposed corresponding to the flexible printed circuit board to dissipate heat from the flexible printed circuit board.

[0091] The second embodiment illustrated may include any one or a combination of more than one of the following features.

[0092] 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, 32b) in 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 ranges from 1 mil to 10 mils.

[0093] In the wireless power transmission system of the second embodiment, the flexible insulating material is formed of polyester, adhesive polyamide or non-adhesive polyamide.

[0094] In the wireless power transmission system of the second embodiment, the Litz winding is formed of a bendable conductive material.

[0095] In the wireless power transmission system of the second embodiment, the operating frequency of the component ranges from 90 kHz to 200 kHz.

[0096] In the wireless power transmission system of the second embodiment, the Litz winding is formed of a plurality of wires electrically isolated from each other, and the plurality of wires are connected in a spiral shape.

[0097] In the wireless power transmission system of the second embodiment, the wires in the first layer (42) and the second layer (44) in the plurality of layers are connected via vias (50).

[0098] In the wireless power transmission system of the second embodiment, the ceramic heat sink includes one or more fluid channels (70).

[0099] 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 adjacent to the flexible printed circuit board.

[0100] 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 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.

[0101] It should be noted that the first embodiment and the second embodiment can also be combined with any of the foregoing embodiments of the present case.

[0102] It should be noted that the above is only the preferred embodiment presented for the purpose of illustrating this case, and this case is not limited to the described embodiment. It should be understood that this case can have various changes in different aspects, all of which do not depart from the scope of this case, and the description and illustration of this case are essentially for illustrative purposes and not for limiting this case. The scope of this case is determined by the appended patent claims. And this case can be variously modified by those skilled in the art, but all do not depart from what is intended to be protected by the appended patent claims.

[0103] 10: Radio power transmission system 12: Transmitting unit 14: Receiving unit 15: Input stage 16, 17: Resonator 18: Output stage 19: Controller 20: Radio power transmission coil system v dc,in: Input voltage v dc,out: Output voltage C in: Input capacitance C out: Output capacitance Q 1, Q 2, Q 3, Q 4, Q 5, Q 6, Q 7, Q 8: Switch C 1, C 2: Capacitance 20a: Flexible PCB litz winding structure 22: Litz winding 28: Flexible PCB litz winding structure 30: Litz winding 32, 32a, 32b, 32c, 32d: Layer 34: Flexible insulating layer 36: Litz winding layout 38: Conductor 40: Double - layer flexible PCB litz winding structure 42: First layer 44: Second layer 46: Conductor 48: Thick wire 50: Through - hole 40a: Double - layer flexible PCB litz winding structure 52: Insulating material x, y: Direction 54: Waveform diagram 56, 58: Curve 60: Waveform diagram 62a: Wireless power transmission component 64: Ceramic heat sink 66: Flexible PCB Litz winding structure 68: Heat source 70: Fluid channel 72: Arrow 62b, 62c: Wireless power transmission component 64a, 64b: Ceramic heat sink 70a, 70b: Fluid channel 73a: Component 78: Ceramic heat sink 74: PCB Litz winding structure 82: Ferrite core 76: Heat source 80: Fluid channel 84, 86, 88, 90: Arrow 92: Thermal resistance network model AT: Ambient temperature HS1, HS2: Heat source Cth0,c, Cth0,w, Cth1,c, Cth1,w, Cth,hs: Heat capacity Rth0,c, Rth0,w, Rth1,c, Rth1,w, Rth,hs: Thermal resistance 73b: Component 94, 96, 98: Arrow 99: Thermal resistance network model 73c: Component 100, 102, 104: Arrow 106: Thermal resistance network model 73d: Component 78a, 78b: Ceramic heat sink 80a, 80b: Fluid channel 108, 110, 112, 114: Arrow 116: Thermal resistance network model 73e: Component 82a, 82b: Ferrite core 118, 120, 122, 124, 126, 128: Arrow 73f: Component 130, 132, 134, 136: Arrow 73g: Component 138, 140, 142, 144: Arrow

Claims

1. A wireless power transmission component, comprising: a flexible printed circuit board including a Litz winding and a flexible insulating material, wherein the Litz winding has a plurality of electrically isolated conductors in a plurality of layers, at least two of the plurality of layers being separated by the flexible insulating material, and the flexible insulating material located between the at least two layers having a minimum thickness between 1 mil and 10 mil; and a ceramic heat sink disposed opposite to the flexible printed circuit board for dissipating heat from the flexible printed circuit board, wherein the ceramic heat sink is in contact with the flexible printed circuit board at the location of the Litz winding.

2. The wireless power transmission assembly as claimed in claim 1, wherein the flexible insulating material is formed of polyester, viscous polyamide, or non-viscous polyamide.

3. The wireless power transmission assembly as claimed in claim 1, wherein the Litz winding is formed of a flexible conductive material.

4. The wireless power transmission assembly as claimed in claim 3, wherein the Litz winding is formed of annealed copper.

5. The wireless power transmission assembly as claimed in claim 1, wherein the Litz winding is formed by a plurality of electrically isolated conductors connected in a helical manner.

6. The wireless power transmission assembly as claimed in claim 1, wherein the conductors in the first and second layers of the plurality of layers are connected via through-holes.

7. The wireless power transmission assembly as claimed in claim 1, wherein the ceramic heat sink includes one or more fluid channels.

8. The wireless power transmission assembly as claimed in claim 1, wherein the ceramic heat sink is disposed adjacent to the flexible printed circuit board.

9. The wireless power transmission assembly as claimed in claim 1, wherein 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 being in contact with the flexible printed circuit board, the first ceramic heat sink being adjacent to a first side of the flexible printed circuit board, and the second ceramic heat sink being adjacent to a second side of the flexible printed circuit board.

10. A wireless power transmission system comprising: a transmitting unit or a receiving unit including an input stage, a resonator, and an assembly, wherein the assembly includes: a flexible printed circuit board including a Litz winding and a flexible insulating material, wherein the Litz winding has a plurality of electrically isolated conductors in a plurality of layers, at least two of the plurality of layers being separated by the flexible insulating material, and the flexible insulating material located between the at least two layers having a minimum thickness between 1 mil and 10 mil; and a ceramic heat sink disposed opposite to the flexible printed circuit board for dissipating heat from the flexible printed circuit board, wherein the ceramic heat sink is in contact with the flexible printed circuit board at the location of the Litz winding.

11. The wireless power transmission system as claimed in claim 10, wherein the flexible insulating material is formed of polyester, viscous polyamide, or non-viscous polyamide.

12. The wireless power transmission system as claimed in claim 10, wherein the Litz winding is formed of a flexible conductive material.

13. The wireless power transmission system as claimed in claim 10, wherein the operating frequency of the component is in the range of 90 kHz to 200 kHz.

14. The wireless power transmission system as claimed in claim 10, wherein the Litz winding is formed by a plurality of electrically isolated conductors connected in a helical manner.

15. The wireless power transmission system as claimed in claim 10, wherein the wires in the first and second layers of the plurality of layers are connected via through-holes.

16. The wireless power transmission system as claimed in claim 10, wherein the ceramic heat sink includes one or more fluid channels.

17. The wireless power transmission system as claimed in claim 10, wherein the ceramic heat sink is disposed adjacent to the flexible printed circuit board.

18. The wireless power transmission system of claim 10, wherein 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 being in contact with the flexible printed circuit board, the first ceramic heat sink being adjacent to a first side of the flexible printed circuit board, and the second ceramic heat sink being adjacent to a second side of the flexible printed circuit board.

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