Novel energy wireless transmission device and method based on electric field coupling

Abstract

The invention discloses a novel energy wireless transmission device and method based on electric field coupling, and aims to solve the problems that an existing parallel coupling mechanism has relatively serious electric field dissipation and a stacked coupling mechanism is insufficient in power transmission capability. The energy transmitting assembly and the energy receiving assembly are of an oppositely-embedded disc structure, a double-LC type resonance compensation network is adopted, and constant current output irrelevant to a load can be achieved. Compared with a parallel disc coupling mechanism, the electric field dissipation of the system to the external environment can be effectively reduced; compared with a stacked disc coupling mechanism, the power transmission capability of the coupling mechanism can be ensured. The power supply slip ring adopting the electric field coupling type wireless power transmission technology is high in electromagnetic interference resistance, small in size, light in weight and low in cost, the problems of abrasion and abrasive dust in power supply of a rotary slip ring are fundamentally solved, and meanwhile the cost and the weight of a power supply device are reduced. The invention relates to the field of wireless power transmission.

Description

Technical Field

[0001] The present invention relates to the field of wireless power transmission, and in particular to a novel wireless energy transmission device and method based on electric field coupling. Background Art

[0002] Special environments such as wind power generation, spacecraft, and oil drilling require power supply for rotating equipment. Currently, most rotating slip rings require physical contact, which can lead to high costs, mechanical wear, and the generation of wear debris, limiting the lifespan of rotating equipment. Wireless power transmission technology fundamentally addresses issues such as inter-ring short circuits and static electricity in slip ring power supply, thereby improving the reliability of the power supply unit.

[0003] In recent years, researchers from various countries have explored the wireless power supply problem of rotating slip rings using inductive power transfer (IPT) technology, achieving some success. However, they have also discovered that IPT systems are limited by power density and EMI. For example, the alternating magnetic field generates eddy currents, leading to power loss; the magnetic field easily radiates outside the system, causing EMI issues; and IPT typically requires expensive Litz wire to address the skin effect and ferrite to guide the magnetic field, increasing system weight and cost.

[0004] Wireless power supply slip rings based on magnetic coupling wireless power transmission technology have defects such as large eddy current loss and high heat generation. Electric field coupling wireless power transmission technology (Capacitive power transfer, CPT) has the advantages of low electromagnetic interference, conducive to miniaturization and heat dissipation design, and easy to achieve simultaneous transmission of energy and signal. It has great potential in the field of rotating wireless power supply in special environments. Therefore, scholars from various countries have tried to apply CPT technology to rotating scenes and further explore practical solutions for WPT technology in the rotating field. At present, electric field coupling wireless power transmission generally adopts a disc-type coupling mechanism. The existing disc-type coupling mechanisms have two more classic forms: parallel and stacked, as shown below. Figure 1 、 Figure 2 As shown. Among them, P1 and P3 are emitter plates, and P2 and P4 are receiver plates. The parallel coupling mechanism consists of a pair of rings and a pair of disks. The two emitter plates and the two receiver plates are in the same plane. Like all parallel coupling mechanisms, it has a more serious electric field dissipation problem. The outer diameter of the plates P1 and P2 of the stacked coupling mechanism is larger than that of the plates P3 and P4. While forming coupling in the outer area, it also shields the electric field dissipation of the inner disk, which can effectively reduce the electric field radiation to the surrounding space; however, this stacked structure increases the energy transmission distance between the plates P1 and P2, which reduces the equivalent mutual capacitance C of the coupling mechanism to a certain extent. MThe value of the coupling mechanism equivalent mutual capacitance C M It is an important parameter to characterize the power transmission capability of the coupling mechanism. In the design process of the coupling mechanism, it is hoped that C M as large as possible), thereby affecting the power transmission capability of the coupling mechanism. Summary of the Invention

[0005] In order to solve the problems of serious electric field dissipation in existing parallel coupling mechanisms and insufficient power transmission capacity of stacked coupling mechanisms, the present invention proposes a new type of wireless energy transmission device and method based on electric field coupling.

[0006] The technical solution adopted by the present invention to solve the above problems is:

[0007] The present invention includes an energy emitting component and an energy receiving component, which are arranged relative to each other. The energy emitting component includes a first emitting plate P1 and a second emitting plate P3, and the energy receiving component includes a first receiving plate P4 and a second receiving plate P2. The first receiving plate P4, the second receiving plate P2, the second emitting plate P3 and the first emitting plate P1 are arranged in parallel from top to bottom. The second receiving plate P2 is provided with an energy transmission cavity, and the shape of the energy transmission cavity corresponds to the shape of the second emitting plate P3. The second emitting plate P3 and the energy transmission cavity form an embedded structure, so that the second emitting plate P3 is closely coupled with the first receiving plate P4, and at the same time, the second receiving plate P2 is closely coupled with the first emitting plate P1.

[0008] Furthermore, the first emitter plate P1 and the second emitter plate P3 are both disk-shaped, and the outer diameter of the first emitter plate P1 is greater than the outer diameter of the second emitter plate P3.

[0009] Furthermore, the first receiving plate P4 is a disk, the second receiving plate P2 is a ring, and the inner diameter of the ring is greater than the outer diameter of the second emitting plate P3.

[0010] Furthermore, the radius of the second emitter plate P3 is 50 mm to 90 mm.

[0011] Furthermore, the radius of the second emitter plate P3 is 75 mm.

[0012] Furthermore, the inner ring radius of the second receiving plate P2 is 10 mm larger than the radius of the second emitting plate P3.

[0013] Based on a new type of energy wireless transmission device based on electric field coupling, the method adopts a dual LC resonant compensation network of a full-bridge inverter network and a full-bridge rectifier network, wherein the transmitting end is composed of an inductor L1 and a capacitor C ex1 The receiving end consists of inductor L2 and capacitor Cex2 Composition, U in is the DC power supply at the transmitter, U out is the DC output voltage after rectification at the output end, U1 is the AC voltage at the input end after inversion, and U2 is the AC voltage at the output end before rectification; due to the effect of the compensation capacitor, the equivalent parallel capacitance of the energy input and output ports can be recorded as C in1 =C ex1 +C1、C in2 =C ex2 +C2; Analyze the parameter relationship of the resonant compensation network components and implement it through the following steps:

[0014] Step 1: Model the coupling mechanism. This mechanism can be considered to consist of two sets of "transmitter-receiver" plates, namely, the first emitter plate P1, the second emitter plate P3, the first receiver plate P4, and the second receiver plate P2, totaling four metal plates. These four metal plates generate six equivalent coupling capacitors.

[0015] Step 2: To simplify the calculation, the six equivalent coupling capacitors can be decoupled into three capacitors using the formula shown in equation (1), and further formed into a π-type equivalent network. The dual LC resonant compensation network after the coupling mechanism is decoupled as a π-type network.

[0016]

[0017] Step 3: Determine the resonant relationship. The bilateral LC compensation network has two constant voltage frequency points. To achieve soft switching of the full-bridge inverter, this design selects the resonant frequency point where the input impedance is inductive. The resonant relationship is shown in Equation (2).

[0018]

[0019] This network can achieve a constant voltage output that is independent of the load when satisfying equation (2). The relationship between U2 and U1 is shown in equation (3).

[0020]

[0021] Step 4: Consider the impedance transformation effect of the inverter and rectifier. Since full-bridge inverter and full-bridge rectifier are used, U in 、U out The relationship between U1 and U2 can be expressed as shown in formula (5).

[0022]

[0023] Substituting equation (4) into equation (3), we can obtain the formula for calculating the output voltage after rectification, as shown in equation (5).

[0024]

[0025] This invention utilizes electric-field-coupled wireless power transmission, a paired disc structure, and a dual-LC resonant compensation network to achieve load-independent constant-current output. Compared to parallel disc coupling mechanisms, this effectively reduces the system's electric field dissipation to the external environment; compared to stacked disc coupling mechanisms, it maintains the coupling mechanism's power transmission capacity.

[0026] The beneficial effects of the present invention are:

[0027] 1. Compared with the traditional parallel disc coupling mechanism, the outer plate of the embedded coupling mechanism of the present invention can shield the electric field dissipation of the inner plate, effectively ensuring the safety of people around the system and the reliable operation of the equipment.

[0028] 2. Compared with the stacked disc coupling mechanism, the hollow design of the second emitter plate of the embedded coupling mechanism of the present invention can effectively enhance the coupling, thereby ensuring the power transmission capability of the coupling mechanism.

[0029] 3. The present invention adopts a dual LC resonant compensation network to achieve constant voltage output regardless of the load. Even if the load fluctuates, the output voltage can remain unchanged, thereby greatly improving the stability of the system.

[0030] 4. Traditional power supply slip rings use contact power supply, which has high system cost, heavy weight, easy wear and short life. The existing wireless power supply slip rings based on magnetic coupling wireless power transmission technology have defects such as large eddy current loss and high heat generation. The power supply slip rings of the present invention, which use electric field coupling wireless power transmission technology, have strong anti-electromagnetic interference, small size, light weight and low cost. They fundamentally overcome the wear and debris problems in the power supply of rotating slip rings, while reducing the cost and weight of the power supply device, providing a highly potential solution for improving the service life of the power supply device of rotating equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a diagram of a parallel disc structure;

[0032] Figure 2 It is a diagram of the stacked disc structure;

[0033] Figure 3 A structural diagram of the embedded coupling mechanism provided by the present invention;

[0034] Figure 4 This is a diagram showing how the equivalent mutual capacitance value of the present invention changes with the radius of P3;

[0035] Figure 5 This is a diagram of the CPT system based on dual LC compensation;

[0036] Figure 6Schematic diagram of the six capacitors generated by the quadrupole plate;

[0037] Figure 7 The diagram of the CPT system based on double LC compensation after the coupling mechanism is decoupled according to the π-type equivalent network;

[0038] Figure 8 The equivalent mutual capacitance C of the three structures M Graph showing the change with energy transmission distance d;

[0039] Figure 9 Electric field dissipation diagram of embedded coupling mechanism;

[0040] Figure 10 Electric field dissipation diagram of the stacked coupling mechanism. DETAILED DESCRIPTION

[0041] Specific implementation method 1: This implementation method describes a new type of wireless energy transmission device based on electric field coupling, such as Figure 3 As shown, it includes an energy emitting component and an energy receiving component, and the energy emitting component and the energy receiving component are arranged relative to each other, the energy emitting component includes a first emitter plate P1 and a second emitter plate P3, and the energy receiving component includes a first receiving plate P4 and a second receiving plate P2. The first receiving plate P4, the second receiving plate P2, the second emitter plate P3 and the first emitter plate P1 are arranged in parallel from top to bottom, and the second receiving plate P2 is provided with an energy transmission cavity, the shape of the energy transmission cavity corresponds to the shape of the second emitter plate P3, and the second emitter plate P3 and the energy transmission cavity form an embedded structure, so that the second emitter plate P3 is closely coupled with the first receiving plate P4, and at the same time, the second receiving plate P2 is closely coupled with the first emitter plate P1.

[0042] Preferably, the first emitter plate P1 and the second emitter plate P3 are both disk-shaped, and the outer diameter of the first emitter plate P1 is greater than the outer diameter of the second emitter plate P3.

[0043] Preferably, the first receiving plate P4 is a disk, the second receiving plate P2 is a ring, and the inner diameter of the ring is larger than the outer diameter of the second emitter plate P3, so that the second emitter plate P3 can pass through the ring of the second receiving plate P2.

[0044] In order to verify the advantages of the embedded coupling mechanism, a parallel disk structure and a stacked disk structure were set as control groups and compared and analyzed through Maxwell simulation. The P3 and P4 plate radii of the two structures were set to 75mm, the inner radius of the P1 and P2 plates of the parallel coupling mechanism was set to 85mm, and the outer radius was set to 110mm. The P1 and P2 plate radii of the stacked coupling mechanism were set to 110mm, and the spacing between the plates on the same side was 10mm. The equivalent mutual capacitance C of the three structures is 0. MThe change of energy transmission distance d is as follows Figure 8 As shown in the simulation results, it can be seen that the equivalent mutual capacitance C generated by the embedded coupling mechanism and the parallel coupling mechanism of the same size is M There is almost no difference, and both are higher than the equivalent mutual capacitance of the stacked coupling mechanism. This verifies that the embedded coupling mechanism can shield the electric field by using its own plates without reducing the power transmission capacity.

[0045] According to the IEEE C95.1 standard, when operating in the 1MHz frequency band, the electric field strength should be lower than 614V / m to ensure personal safety. In Maxwell, the electric field analysis of the parallel coupling mechanism and the embedded coupling mechanism under the same plate voltage excitation is performed, and the results are as follows: Figure 9 、 Figure 10 As shown in the figure, the minimum safety distance for the parallel coupling mechanism is 145mm, while the minimum safety distance for the embedded coupling mechanism is only 76mm, a 47.6% reduction compared to the parallel coupling mechanism. Therefore, the embedded coupling mechanism can effectively reduce the electric field dissipation of the CPT system to the surrounding environment.

[0046] Preferably, the application of this embodiment limits the outer diameter of the coupling mechanism to 220mm, and the inner ring radius of the second receiving plate P2 is 10mm larger than the radius of the second emitter plate P3, so that the coupling mechanism has a certain anti-offset ability and reduces the cross-coupling capacitance that is not conducive to energy transmission. In this way, with the goal of increasing the mutual capacitance value CM of the coupling mechanism, the radius r1 of the second emitter plate P3 is used as a variable to optimize the size design of the coupling mechanism. A simulation model of the embedded coupling mechanism is established in Maxwell, and the energy transmission distance is set to 1mm, the spacing between the plates on the same side is 10mm, and the radius r1 of the second emitter plate P3 is dynamically simulated from 50mm to 90mm to obtain the equivalent mutual capacitance value C of the coupling mechanism. M The curve of the inner plate length l2 is as follows Figure 4 shown.

[0047] Simulation results show that when the radius of the second emitter plate P3 is 75 mm, the coupling mechanism generates the maximum mutual capacitance CM, achieving optimal power transmission. Therefore, the radius of the second emitter plate P3 is designed to be 75 mm, which in turn determines the inner diameter of the second receiver plate P2 to be 85 mm.

[0048] Specific implementation method 2: This implementation method describes a new type of wireless energy transmission method based on electric field coupling, such as Figure 5 As shown, a dual LC resonant compensation network is used, which is composed of a full-bridge inverter network and a full-bridge rectifier network. The transmitter is composed of an inductor L1 and a capacitor C ex1 The receiving end consists of inductor L2 and capacitor C ex2 Composition, Uin is the DC power supply at the transmitter, U out is the DC output voltage after rectification at the output end, U1 is the AC voltage at the input end after inversion, and U2 is the AC voltage at the output end before rectification; due to the effect of the compensation capacitor, the equivalent parallel capacitance of the energy input and output ports can be recorded as C in1 =C ex1 +C1、C in2 =C ex2 +C2; Analyze the parameter relationship of the resonant compensation network components and implement it through the following steps:

[0049] Step 1: Model the coupling mechanism. Since the coupling mechanism can actually be considered to have two sets of "transmitter-receiver" plates (first emitter plate P1, second emitter plate P3, first receiver plate P4, and second receiver plate P2), that is, a total of four metal plates. These four metal plates can generate six equivalent coupling capacitors, such as Figure 6 shown.

[0050] Step 2: To simplify the calculation, the formula shown in formula (1) can be used to decouple the six capacitors into three capacitors, and further form a π-type equivalent network. The dual LC resonant compensation network after decoupling the coupling mechanism into a π-type network is as follows: Figure 7 shown.

[0051]

[0052] Step 3: Determine the resonant relationship. The bilateral LC compensation network has two constant voltage frequency points. To achieve soft switching of the full-bridge inverter, this design selects the resonant frequency point where the input impedance is inductive. The resonant relationship is shown in Equation (2).

[0053]

[0054] This network can achieve a constant voltage output that is independent of the load when satisfying equation (2). The relationship between U2 and U1 is shown in equation (3).

[0055]

[0056] Step 4: Consider the impedance transformation effect of the inverter and rectifier. Since full-bridge inverter and full-bridge rectifier are used, U in 、U out The relationship between U1 and U2 can be expressed as shown in formula (5).

[0057]

[0058] Substituting equation (4) into equation (3), we can obtain the formula for calculating the output voltage after rectification, as shown in equation (5).

[0059]

[0060] This invention, based on electric-field-coupled wireless power transmission technology, utilizes a recessed circular disc structure to power rotating equipment. The system employs a dual LC resonant compensation network to achieve a load-independent constant voltage output. Compared to the coupling mechanisms of traditional circular disc-type electric-field-coupled wireless power transmission systems, the recessed coupling mechanism proposed in this invention maintains power transmission capacity while reducing the system's electric field dissipation to the external space.

[0061] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any technician familiar with the present profession can make some changes or modifications to equivalent embodiments of equivalent changes using the technical content disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent replacement and improvement of the above embodiments made according to the technical essence of the present invention, within the spirit and principles of the present invention, without departing from the content of the technical solution of the present invention, shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A novel wireless energy transmission device based on electric field coupling, comprising an energy transmitting component and an energy receiving component, wherein the energy transmitting component and the energy receiving component are arranged opposite to each other, and characterized in that: The energy transmitting component includes a first transmitting plate (P1) and a second transmitting plate (P3), and the energy receiving component includes a first receiving plate (P4) and a second receiving plate (P2). The first receiving plate (P4) and the second receiving plate (P2), the second transmitting plate (P3) and the first transmitting plate (P1) are arranged in parallel from top to bottom, and the second receiving plate (P2) is provided with an energy transmission cavity, and the shape of the energy transmission cavity corresponds to the shape of the second transmitting plate (P3).

2. According to claim 1, a novel wireless energy transmission device based on electric field coupling is characterized in that: The first emitter plate (P1) and the second emitter plate (P3) are both disk-shaped, and the outer diameter of the first emitter plate (P1) is larger than the outer diameter of the second emitter plate (P3).

3. According to claim 1, a novel wireless energy transmission device based on electric field coupling is characterized in that: The first receiving electrode plate (P4) is a disk body, and the second receiving electrode plate (P2) is a ring body, and the inner diameter of the ring body is greater than the outer diameter of the second emitting electrode plate (P3).

4. According to claim 1, a novel wireless energy transmission device based on electric field coupling is characterized in that: The radius of the second emitter plate (P3) is 50 mm to 90 mm.

5. According to claim 4, a novel wireless energy transmission device based on electric field coupling is characterized in that: The radius of the second emitter plate (P3) is 75 mm.

6. The novel energy wireless transmission device based on electric field coupling according to claim 1 is characterized in that: The inner ring radius of the second receiving electrode plate (P2) is 10 mm larger than the radius of the second emitting electrode plate (P3).

7. A transmission method of a novel energy wireless transmission device based on electric field coupling according to any one of claims 1 to 6, characterized in that: The method adopts a dual LC resonant compensation network of a full-bridge inverter network and a full-bridge rectifier network, wherein the transmitter end is composed of an inductor L1 and a capacitor C ex1 The receiving end consists of inductor L2 and capacitor C ex2 Composition: in is the DC power supply at the transmitting end, U out is the DC output voltage after rectification at the output end, U1 is the AC voltage at the input end after inversion, and U2 is the AC voltage at the output end before rectification; due to the effect of the compensation capacitor, the equivalent parallel capacitance of the energy input and output ports can be recorded as C in1 =C ex1 +C1, C in2 =C ex2 +C2, analyzing the relationship between the parameters of the resonant compensation network components, wherein the analysis of the relationship between the parameters of the resonant compensation network components is achieved by the following steps: Step 1: Modeling the coupling mechanism, where the four metal plates of the coupling mechanism, namely the first emitter plate (P1), the second emitter plate (P3), the first receiving plate (P4) and the second receiving plate (P2), can generate six equivalent coupling capacitors; Step 2: Decouple the six equivalent coupling capacitors into three capacitors, and further form a π-type equivalent network; Step 3: Determine the resonance relationship; Step 4: Consider the impedance transformation effect of the inverter and rectifier.

8. The novel energy wireless transmission method based on electric field coupling according to claim 7 is characterized in that: In step 2, the six equivalent coupling capacitors in step 1 are decoupled into three capacitors using the formula shown in equation (1), and a π-type equivalent network is further formed, and the coupling mechanism is decoupled according to the π-type network to form a double LC resonant compensation network.

9. The novel energy wireless transmission method based on electric field coupling according to claim 7 is characterized in that: In step 3, the bilateral LC compensation network has two constant voltage frequency points, and the resonant frequency point with inductive input impedance is selected. The resonant relationship is shown in formula (2); This network can achieve a constant voltage output that is independent of the load when the condition of formula (2) is met. The relationship between U2 and U1 is shown in formula (3).

10. The novel energy wireless transmission method based on electric field coupling according to claim 7 is characterized in that: In step 4, due to the use of full-bridge inverter and full-bridge rectification, U in , U out The relationship between U1 and U2 can be expressed as shown in formula (5): Substituting equation (4) into equation (3), we can get the formula for calculating the output voltage after rectification, as shown in equation (5).

Images