A capacitive-inductive integrated magnetic coupling mechanism based on iron-based nanocrystalline magnetic core

Abstract

The present invention proposes a capacitive-inductive integrated magnetic coupling mechanism based on an iron-based nanocrystalline magnetic core, comprising a transmitting-side magnetic coupling mechanism and a receiving-side magnetic coupling mechanism, wherein both the transmitting-side magnetic coupling mechanism and the receiving-side magnetic coupling mechanism are shielding layers formed by staggered lamination of iron-based nanocrystalline ribbons and organic insulating films, a double D coil is arranged on the shielding layer, and the double D coil and the shielding layer form a double D coil group, wherein the two D coils are connected in series in reverse order so that the currents flowing into the coils are in opposite directions, thereby being equivalent to the north and south poles of a magnet, and providing a closed magnetic circuit for the magnetic flux; the double D coil group integrates the inductance and capacitance in a resonant compensation circuit into the magnetic coupling mechanism at the same time, and the mechanism is mainly used in wireless power transmission systems, and the present invention integrates the resonant capacitor into the magnetic core to replace the expensive film capacitor in a traditional resonant converter, thereby improving the system power density and economy.

Description

Technical Field

[0001] The present invention relates to a novel magnetic core structure applied in the field of wireless power transmission, and in particular to a capacitive-inductive integrated magnetic coupling mechanism based on an iron-based nanocrystalline magnetic core. Background Art

[0002] Wireless power transmission, as an emerging non-contact energy transmission technology, can provide safer and more convenient charging solutions for various vehicles such as electric vehicles, trains and ships, and effectively solve the "difficult charging" problem brought about by the electrification of vehicles. Autonomous driving will be the development trend of electric vehicles in the future, and wireless power transmission technology can be combined with autonomous driving to achieve full automation of vehicle driving and charging, which is an important technical support for promoting the goal of intelligent networking of vehicle-road network collaboration. In addition, in specific application scenarios, such as unmanned material transport vehicles in smart factories, port engineering logistics vehicles and underwater detection machinery, the demand for wireless charging technology is more urgent.

[0003] After years of technical research and development, static wireless power transmission technology has initially met the technical requirements for commercialization. However, low power density and high cost are still the main obstacles to further market promotion of wireless power transmission technology in the field of electric vehicle charging. Among them, the magnetic coupling mechanism is the largest component in the wireless charging system, and its design has a crucial impact on the overall power density of the system. The current magnetic coupling mechanism, which is mainly based on ferrite cores, has low magnetic saturation intensity and large hysteresis loss, which essentially restricts the further improvement of power density.

[0004] The related experiments in "Characterization of Nanocrystalline Flake Ribbon for High Frequency Magnetic Cores" pointed out that the magnetic saturation intensity of ferrite cores is low, about 0.3T, and when the core temperature is higher than 85℃, its core loss is positively correlated with temperature. In "Highly Efficient 11.1 kW Wireless Power Transfer Utilizing Nanocrystalline Ribbon Cores", it is pointed out that after the magnetic field in the core enters the saturation region, the relative magnetic permeability of the core will drop significantly, making it impossible for the system to operate at the original rated resonance point, and its current waveform will be significantly distorted. Therefore, in order to increase the transmission power of the system, the volume of the ferrite core can only be increased. These shortcomings have become the main obstacles to further improving the power of wireless power transmission systems.

[0005] On the other hand, since the wireless power transmission system mainly works in a resonant state, if series resonant compensation is used, the withstand voltage of the resonant capacitor often needs to reach 2 kV-3 kV RMS. Therefore, a large number of single capacitors are required to be combined in series and parallel to form the final resonant capacitor. Taking the Electronic Concepts 5PT series of film capacitors as an example, if a 20-30kW wireless charging system is built, the cost of the resonant capacitor is about US$500-700. In addition, other resonant compensation topologies such as LCC compensation networks require more compensation capacitors, which will make the overall system larger and more expensive.

[0006] Iron-based nanocrystals are a kind of metal-based soft magnetic material with low hysteresis loss and high magnetic saturation threshold (up to 1T). Using iron-based nanocrystals to form the magnetic coupling mechanism in the WPT system can effectively avoid the magnetic saturation problem and reduce the core loss. At the same time, integrating the resonant capacitor into the core can significantly improve the power density of the system. Summary of the invention

[0007] The purpose of the present invention is to solve the problem of large magnetic core volume and high cost in the current WPT system, and proposes a capacitance-inductance integrated magnetic coupling mechanism based on a thin-layer laminated iron-based nanocrystalline magnetic core. The mechanism is mainly used in wireless power transmission systems, using a thin layer of iron-based nanocrystals and an organic insulating film to be laminated on each other as a magnetic core to replace the traditional ferrite core, and using the high conductivity magnetic material of the iron-based nanocrystal as the pole plate, and the organic insulating film on the magnetic material base as the dielectric, to integrate the resonant capacitor into the magnetic core to form a capacitance-inductance integrated magnetic coupling mechanism. The capacitance-inductance integrated magnetic coupling mechanism based on the iron-based nanocrystalline magnetic core proposed by the present invention integrates the resonant capacitor into the magnetic core, replacing the expensive thin-film capacitor in the traditional resonant converter, eliminating the bulky capacitor space, and can significantly improve the system power density and economy.

[0008] The purpose of the present invention can be achieved by at least one of the following technical solutions.

[0009] A capacitive-inductive integrated magnetic coupling mechanism based on an iron-based nanocrystalline magnetic core comprises a transmitting-side magnetic coupling mechanism and a receiving-side magnetic coupling mechanism; electric energy is transmitted to the receiving-side magnetic coupling mechanism through an alternating magnetic field generated by the transmitting-side magnetic coupling mechanism;

[0010] The transmitting-side magnetic coupling mechanism and the receiving-side magnetic coupling mechanism both include a shielding layer, wherein the shielding layer includes an iron-based nanocrystalline strip and an organic insulating film, and the iron-based nanocrystalline strip and the organic insulating film are alternately stacked;

[0011] A double D coil is arranged on the shielding layer, and the double D coil and the shielding layer constitute a double D coil group. The two D coils are connected in series in reverse order so that the currents flowing into the coils are in opposite directions, thereby being equivalent to the north and south poles of the magnet, providing a closed magnetic circuit for the magnetic flux; the double D coil group integrates the inductance and capacitance in the resonance compensation circuit into the magnetic coupling mechanism at the same time.

[0012] Furthermore, the double D coil is wound by Litz wire.

[0013] Furthermore, the double D coil consists of two square coils laid side by side.

[0014] Furthermore, the iron-based nanocrystalline ribbons and the organic insulating films are stacked alternately, and the stacking direction is perpendicular to the main magnetic flux direction.

[0015] Furthermore, a magnetic core is formed by stacking iron-based nanocrystals and organic insulating films, and the high conductivity of iron-based nanocrystals is used as electrodes of a multilayer film capacitor. The organic insulating film between each iron-based nanocrystal strip is used as a dielectric layer to form a resonant capacitor, thereby integrating the capacitor into the magnetic core to achieve capacitor-inductor integration.

[0016] Furthermore, the organic insulating film is a polyester film or a polyimide film.

[0017] Furthermore, the iron-based nanocrystals and the organic insulating film are fabricated into a ribbon shape.

[0018] Furthermore, the thickness of the Fe-based nanocrystalline ribbon is , the thickness of the organic insulating film tape is .

[0019] Furthermore, iron-based nanocrystalline ribbons are used as electrodes of a multilayer thin-film capacitor, and the organic insulating film between each iron-based nanocrystalline ribbon is used as a dielectric layer to form a resonant capacitor; adjacent iron-based nanocrystalline ribbons are placed horizontally offset to construct a multilayer thin-film capacitor, with odd-numbered iron-based nanocrystalline ribbons as positive electrodes and even-numbered iron-based nanocrystalline ribbons as negative electrodes, and the capacitance value is adjusted by changing different organic insulating film materials or changing its own thickness.

[0020] Furthermore, the load is a pure resistive load, a resistive-inductive load, or a resistive-capacitive load.

[0021] Furthermore, the load is a pure resistive load, a resistive-inductive load, or a resistive-capacitive load.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The low hysteresis loss and high magnetic saturation of the iron-based nanocrystalline ribbon core are used as the magnetic core in the wireless power transmission system. At the same time, the high conductivity of the iron-based nanocrystalline ribbon is used as the electrode of the multilayer film capacitor. The organic insulating film between each iron-based nanocrystalline ribbon is used as a dielectric layer to form the resonant capacitor in the wireless power transmission system, thereby eliminating the expensive and bulky resonant compensation capacitor in the wireless power transmission system, greatly improving the power density of the system. The low hysteresis loss and high magnetic saturation of iron-based nanocrystals also enable the transmission power of the system to be further improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The invention discloses an application of the capacitive-inductive integrated magnetic core in a series resonant WPT system;

[0025] Figure 2 It is a specific structural diagram of the capacitance-inductance integrated magnetic core proposed in the present invention;

[0026] Figure 3 It is the result of simulation experiment conducted to verify the feasibility of the present invention;

[0027] Figure 4 This is a typical schematic diagram of the components of a wireless charging system;

[0028] Figure 5 It is a schematic diagram of the thin layer stacking method of iron-based nanocrystalline magnetic core and electrode lead-out. DETAILED DESCRIPTION

[0029] The specific implementation of the invention is further described below in conjunction with the accompanying drawings, but the implementation and protection of the invention are not limited thereto.

[0030] In the present embodiment, a capacitive-inductive integrated magnetic coupling mechanism based on an iron-based nanocrystalline magnetic core uses iron-based nanocrystalline ribbons and organic insulating films to form a magnetic core, and uses the high conductivity of iron-based nanocrystals as electrodes of a multilayer film capacitor. The organic insulating film between each iron-based nanocrystalline ribbon is used as a dielectric layer to form a resonant capacitor, thereby integrating the capacitor into the magnetic core to achieve capacitor-inductor integration.

[0031] The capacitive-inductive integrated magnetic coupling mechanism comprises a transmitting-side magnetic coupling mechanism and a receiving-side magnetic coupling mechanism; electric energy is transmitted to the receiving-side magnetic coupling mechanism through the alternating magnetic field generated by the transmitting-side magnetic coupling mechanism.

[0032] The transmitting side magnetic coupling mechanism and the receiving side magnetic coupling mechanism are both shielding layers composed of iron-based nanocrystal (FeCuNbSiB) tapes and organic insulating films stacked alternately. A double D coil is provided on the shielding layer, and the double D coil and the shielding layer constitute a double D coil group. The double D coil consists of two rectangular or square coils laid side by side, each coil is regarded as a D coil, and the two D coils are connected in series in reverse order so that the currents flowing into the coils are in opposite directions, which is equivalent to the north and south poles of the magnet, providing a closed magnetic circuit for the magnetic flux. The double D coil group integrates the inductance and capacitance in the resonant circuit of the wireless charging system into the magnetic coupling mechanism at the same time.

[0033] This mechanism is mainly used in wireless power transmission systems, such as Figure 1 As shown, a wireless charging system based on a capacitive-inductive integrated magnetic coupling mechanism includes a transmitting device and a receiving device, wherein the transmitting device includes a PFC rectifier module, a high-frequency inverter module, a transmitting-side magnetic coupling mechanism and a resonant compensation circuit connected in sequence; the receiving device includes a receiving-side magnetic coupling mechanism, a resonant compensation circuit, a rectifier circuit, an output control circuit and a load connected in sequence.

[0034] As an embodiment, the organic insulating film may be a polyethylene terephthalate (PET) film or a polyimide film.

[0035] Iron-based nanocrystals (FeCuNbSiB) have the characteristics of low hysteresis loss and high magnetic saturation. After the nanocrystal ribbon is attached to the organic insulating film substrate, a stacking structure is adopted, so that the stacking direction is perpendicular to the main magnetic flux direction, which can significantly reduce eddy current loss and hysteresis loss. The shielding layer composed of the iron-based nanocrystals and the organic insulating film can effectively confine the magnetic field within the shielding layer, eliminating the influence of the magnetic field on the electronic devices or devices under the shielding layer. It can be regarded as the magnetic shielding layer symmetrically mirroring the magnetic flux of the lower half of the magnetic field to the upper half, and superimposing it with the magnetic flux of the upper half, so that the double D coil group can obtain a larger magnetic field strength on one side.

[0036] Since the electrical conductivity of iron-based nanocrystals is as high as 5×10 6 S / m, while organic insulating film is an excellent dielectric material (relative dielectric constant is 3-5). Figure 2 As shown in (a), adjacent iron-based nanocrystalline ribbons are placed horizontally offset. Counting from top to bottom, the odd-numbered iron-based nanocrystalline ribbons are used as positive electrodes, the even-numbered iron-based nanocrystalline ribbons are used as negative electrodes, and the organic insulating film is used as a dielectric, thereby constructing a multilayer film capacitor to achieve the purpose of integrating the resonant capacitor into the magnetic coupling mechanism.

[0037] like Figure 2As shown in (b), adjacent iron-based nanocrystalline ribbons can also be placed vertically offset, with capacitor electrodes drawn out from the top and bottom of the magnetic core respectively, to construct a multilayer thin film capacitor, with odd-numbered iron-based nanocrystalline ribbons as positive electrodes and even-numbered iron-based nanocrystalline ribbons as negative electrodes. The capacitance value of the mechanism can be adjusted by changing different organic insulating film materials or changing its own thickness.

[0038] Figure 3 The invention discloses an application of the capacitive-inductive integrated magnetic core in a WPT system. Figure 4 (d) is a capacitive-inductive integrated magnetic core structure protected by the present invention, wherein a layer of organic insulating film strip 2 is added between two adjacent iron-based nanocrystalline strips (1, 1'), and adjacent iron-based nanocrystalline strips are horizontally placed and offset. Odd-numbered iron-based nanocrystalline strips 1 are used as positive electrodes, even-numbered iron-based nanocrystalline strips 1' are used as negative electrodes, and organic insulating films are used as dielectrics, thereby constructing a multilayer film capacitor, thereby integrating the resonant capacitor into the magnetic coupling mechanism 6.

[0039] like Figure 3 As shown in FIG. 1 , in the classic SS-type WPT system, resonant compensation capacitors C1 and C2 need to be connected in series at both the power transmission end and the power receiving end. In the traditional ferrite core, the compensation capacitors that need to be connected in series are large in size and high in cost. Figure 4 The double D coil assembly (including the double D coil 3 and the shielding layer 4) shown in (a) replaces the inductor coil and the resonant compensation capacitor ( Figure 1 L1, C1 and L2, C2) in order to improve the transmission power and power density of the system.

[0040] like Figure 4 As shown in (a), the double D coil 3 in the double D coil group can be wound by Litz wire, and the shielding layer 4 is composed of iron-based nanocrystalline strips 1 and 1 ′ and an organic insulating film strip 2 stacked together. Figure 4 (b) shows a double D coil assembly Figure 4 The magnetic flux loop in (a). The magnetic field distribution of the double D coil group presents a unilateral magnet-type magnetic field distribution (the magnetic fields on the upper and lower sides of the magnet start from the North Pole and converge at the South Pole). It can be regarded as the lower half of the magnetic flux in the magnet-type magnetic field is symmetrically mirrored to the upper half due to the magnetic shielding effect of the iron-based nanocrystalline core, and superimposed with the magnetic flux of the upper half. Therefore, by using a double D coil group, a greater magnetic field intensity can be obtained on a single side, and the magnetic field leakage on the other side can be effectively reduced. This magnetic field distribution characteristic of the double D coil group is more suitable for wireless power transmission applications. In addition, the double D coil group has better anti-dislocation ability and a higher quality factor, which can further improve the transmission efficiency.

[0041] like Figure 4As shown in (c), the thickness of the iron-based nanocrystalline magnetic core is equal to the product of the thickness of the iron-based nanocrystalline strip (1, 1') and the number of stacked layers, and the width and length of the iron-based nanocrystalline magnetic core are equal to the width and length of the iron-based nanocrystalline strip. In practical applications, the iron-based nanocrystalline strip can be made into a suitable size according to actual application requirements, and a suitable number of layers can be selected for stacking. In addition, the iron-based nanocrystalline magnetic core proposed in the present invention adopts a layered stacking structure, and the organic insulating film strip 2 is applied between two adjacent iron-based nanocrystalline strips. Therefore, when the magnetic core is working normally, the eddy current loop 5 is suppressed on each cross section of the iron-based nanocrystalline strip, and the thickness of the iron-based nanocrystalline is extremely thin, which can greatly reduce the eddy current loss.

[0042] Figure 4 (d) shows a laminated structure of the shielding layer. As a preferred embodiment, the thickness of the iron-based nanocrystalline strip (1, 1') is , the thickness of the organic insulating film tape 2 is A layer of organic insulating film is applied between two adjacent iron-based nanocrystalline ribbons. A suitable number of layers of iron-based nanocrystalline ribbons and organic insulating films are stacked in such a staggered stacking manner to a required thickness to form a shielding layer 4.

[0043] in Figure 4 (b) is a double D coil group ( Figure 2 (a) is the front view, i.e. the view from the x-axis in the figure; Figure 4 (c) is a side view of the double D coil assembly, i.e., a view viewed from the y-axis in the figure; Figure 4 (d) is a top view of the double D coil group, that is, a view viewed from the z-axis in the figure.

[0044] The main magnetic flux direction in the actual double D coil group is the same as the main magnetic flux direction in the simplified solenoid core. Figure 5 The figure shows the simulation result of the simplified solenoid core model conducted to verify the feasibility of the present invention. The capacitive-inductive integrated magnetic coupling mechanism based on the iron-based nanocrystalline core of the present invention is applicable to a frequency range of 10kHz-200kHz.

[0045] Figure 5 (c) is a simplified two-dimensional cross-sectional diagram of the solenoid core model. It can be seen that in the iron-based nanocrystalline ribbon (1, 1'), the electric field 7 is distributed perpendicular to the direction of the nanocrystalline ribbon, and the magnetic field 8 is distributed along the direction of the iron-based nanocrystalline ribbon. The magnetic field and the electric field are orthogonal to each other. During normal operation, the electric field and the magnetic field in the core are orthogonal to each other and do not interfere with each other. The core constitutes a four-port network element, and the inductor and the capacitor have no internal electrical connection.

[0046] Figure 5 (a) and Figure 5(b) are the simulation results of the magnetic field along the iron-based nanocrystalline band and the electric field perpendicular to the iron-based nanocrystalline band, respectively. The simulation shows that the magnetic field distribution along the iron-based nanocrystalline band is the same before and after the voltage is applied to Cap+1 and Cap-1'. The electric field distribution perpendicular to the iron-based nanocrystalline band is the same before and after the magnetic field excitation. That is, the electric field and the magnetic field in the integrated capacitive-inductive core based on iron-based nanocrystals proposed in the present invention do not interfere with each other.

[0047] From this simulation, it can be seen that the feasibility of the present invention is verified. By adopting the capacitor-inductor integrated magnetic core structure proposed in the present invention, the inductor and resonant capacitor in the WPT system can be integrated into the magnetic core, thereby improving the power density of the WPT system and reducing the cost of the system.

[0048] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well.

Claims

1. A capacitive-inductive integrated magnetic coupling mechanism based on an iron-based nanocrystalline magnetic core, characterized in that: It includes a transmitting side magnetic coupling mechanism and a receiving side magnetic coupling mechanism; the electric energy is transmitted to the receiving side magnetic coupling mechanism through the alternating magnetic field generated by the transmitting side magnetic coupling mechanism; The transmitting-side magnetic coupling mechanism and the receiving-side magnetic coupling mechanism both include a shielding layer, and the shielding layer includes an iron-based nanocrystalline ribbon and an organic insulating film, and the iron-based nanocrystalline ribbon and the organic insulating film are staggered and stacked; the iron-based nanocrystalline ribbon is used as an electrode of a multilayer thin-film capacitor, and the organic insulating film between each iron-based nanocrystalline ribbon is used as a dielectric layer to form a resonant capacitor; adjacent iron-based nanocrystalline ribbons are placed horizontally offset to construct a multilayer thin-film capacitor, and odd-numbered iron-based nanocrystalline ribbons are used as positive electrodes, and even-numbered iron-based nanocrystalline ribbons are used as negative electrodes, and the capacitance value is adjusted by changing different organic insulating film materials or changing its own thickness; A double D coil is arranged on the shielding layer, and the double D coil and the shielding layer constitute a double D coil group. The two D coils are connected in series in reverse order so that the currents flowing into the coils are in opposite directions, thereby being equivalent to the north and south poles of the magnet, providing a closed magnetic circuit for the magnetic flux; the double D coil group integrates the inductance and capacitance in the resonance compensation circuit into the magnetic coupling mechanism at the same time.

2. The capacitive-inductive integrated magnetic coupling mechanism based on an iron-based nanocrystalline magnetic core according to claim 1, characterized in that: The double D coil is wound from Litz wire.

3. The capacitive-inductive integrated magnetic coupling mechanism based on an iron-based nanocrystalline magnetic core according to claim 1, characterized in that: The Double D coil consists of two square coils laid side by side.

4. The capacitive-inductive integrated magnetic coupling mechanism based on an iron-based nanocrystalline magnetic core according to claim 1, characterized in that: The iron-based nanocrystalline ribbons and the organic insulating films are stacked alternately, and the stacking direction is perpendicular to the main magnetic flux direction.

5. The capacitive-inductive integrated magnetic coupling mechanism based on an iron-based nanocrystalline magnetic core according to claim 1, characterized in that: The magnetic core is composed of iron-based nanocrystal strips and organic insulating films. The high conductivity of iron-based nanocrystals is used as electrodes of multilayer film capacitors. The organic insulating films between each iron-based nanocrystal strip are used as dielectric layers to form resonant capacitors, thereby integrating the capacitors into the magnetic core to achieve capacitor-inductor integration.

6. The capacitive-inductive integrated magnetic coupling mechanism based on an iron-based nanocrystalline magnetic core according to claim 1, characterized in that: The organic insulating film is a polyester film or a polyimide film.

7. The capacitive-inductive integrated magnetic coupling mechanism based on an iron-based nanocrystalline magnetic core according to claim 6, characterized in that: Iron-based nanocrystals and organic insulating films are made into ribbon shapes.

8. The capacitive-inductive integrated magnetic coupling mechanism based on an iron-based nanocrystalline magnetic core according to claim 6, characterized in that: The thickness of the Fe-based nanocrystalline ribbon is , the thickness of the organic insulating film tape is .

9. A capacitive-inductive integrated magnetic coupling mechanism based on an iron-based nanocrystalline magnetic core according to any one of claims 1 to 8, characterized in that: The load is a pure resistive load, a resistive-inductive load, or a resistive-capacitive load.

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