Wireless electric energy transmission system based on three-pole-plate single-capacitor coupling

Abstract

The invention relates to the technical field of electric field coupling wireless power transmission (EC-WPT), and particularly discloses a wireless power transmission system based on three-pole-plate single-capacitance coupling, and an original bipolar plate coupling mechanism of a bipolar plate single-capacitance coupling WPT system is changed into a three-pole-plate coupling mechanism. A relay polar plate is inserted into an air medium between two original power polar plates (a transmitting polar plate and a receiving polar plate), the spatial positions of the three polar plates are kept parallel, and the two power polar plates can be completely projected on the relay polar plate all the time within an allowable deviation range. The circuit topology enables the transmitting polar plate to induce charges, the transmitting polar plate and the relay polar plate form an electric field, then the relay polar plate enables the receiving polar plate to induce charges, an electric field is formed, and then power is supplied to electric equipment. According to the system, 100% offset resistance is realized in the two-dimensional plane of the receiving and transmitting polar plate in the area of the relay polar plate, and the system has the outstanding advantages of high offset tolerance and low cost.

Description

Technical Field

[0001] The present invention relates to the technical field of electric-field coupled wireless power transfer (EC-WPT), and in particular to a wireless power transmission system based on three-electrode single capacitor coupling. Background Art

[0002] Wireless Power Transfer (WPT) technology has many advantages over traditional charging methods. First, WPT technology makes power transmission more flexible and suitable for scenarios where space is limited or wiring is impossible, such as medical equipment, electric vehicle charging systems, and remote sensor networks. Second, WPT technology reduces the wear and maintenance costs of physical connections, especially in harsh environments or when equipment is frequently moved. In addition, WPT technology can improve the safety of the system and avoid electrical accidents caused by broken wires or poor contact.

[0003] The more mature WPT technologies can be divided into Magnetic-Coupled Wireless Power Transfer (MC-WPT) and Electric Field Coupled Wireless Power Transfer (EC-WPT) according to the different coupling energy fields. Compared with MC-WPT, EC-WPT avoids the need for heavy Litz wires and ferrite cores, has the advantages of simpler and more variable coupling mechanisms, lower costs, and the ability to transmit energy through metal obstacles.

[0004] Single capacitor coupled wireless power transmission (SCC-WPT) technology is a common implementation method of EC-WPT technology. SCC-WPT technology can complete energy transmission through a pair of metal plates using the principle of electric field coupling. By reducing the number of plates, the influence of cross-coupling capacitance between multiple plates is eliminated, which is very suitable for solving the problem of wireless charging of electrical equipment in a two-dimensional plane. However, the ability of this technology to provide stable charging electrical parameters depends on the facing area of ​​the above-mentioned pair of metal plates, that is, the pair of metal plates cannot have too much relative offset in the two-dimensional plane, otherwise it will change the capacitance of the single capacitor, thereby affecting the output of the wireless charging system. For most of the current industrial or household appliances, it is very common that there is a relative position deviation between the receiving plate (receiving plate) and the transmitting plate (transmitting plate) of the electrical equipment and they cannot be completely facing each other. Therefore, it is very important to improve the anti-offset performance of the SCC-WPT system. Summary of the invention

[0005] The present invention provides a wireless power transmission system based on three-pole single capacitor coupling, and solves the technical problem that the existing two-pole single capacitor coupling wireless power transmission system has poor anti-deviation performance.

[0006] In order to solve the above technical problems, the present invention provides a wireless power transmission system based on three-plate single capacitor coupling, including a three-plate coupling mechanism; the three-plate coupling mechanism includes an emitter plate P arranged in sequence 1 、Relay plate P 3 and receiving plate P 2 , where the emitter plate P 1 Connect the transmitting circuit and the receiving plate P 2 Connect the receiving circuit, relay plate P 3 No connection; emitter plate P 1 , receiving plate P 2 、Relay plate P 3 The parameters satisfy: within the offset range, the emitter plate P 1 , receiving plate P 2 At the relay plate P 3 The projected area on the emitter plate P 1 , receiving plate P 2 area.

[0007] Preferably, the relay plate P 3 Adopt rectangular metal plate, with relay plate P 3 The corner of the coordinate is the origin o, with the relay plate P 3 The length, width and thickness directions are x-axis, y-axis and z-axis respectively to establish a three-dimensional rectangular coordinate system. 3 The dimensions meet:

[0008] When the emitter plate P 1 The maximum x-axis offset Δx occurs 13m The maximum angle α that occurs at the same time 13m When offset, the emitter plate P 1 The projection on the xoy plane is located at the relay plate P 3 superior;

[0009] When the receiving plate P 2 The maximum x-axis offset Δx occurs 23m The maximum angle α that occurs at the same time 23m When offset, the receiving plate P 2 The projection on the xoy plane is located at the relay plate P 3 superior;

[0010] When the emitter plate P 1 Maximum y-axis offset Δy occurs 13m The maximum angle α that occurs at the same time 13mWhen offset, the emitter plate P 1 The projection on the xoy plane is located at the relay plate P 3 superior;

[0011] When the receiving plate P 2 Maximum y-axis offset Δy occurs 23m The maximum angle α that occurs at the same time 23m When offset, the receiving plate P 2 The projection on the xoy plane is located at the relay plate P 3 superior.

[0012] Preferably, the emitter plate P 1 , receiving plate P 2 Both use rectangular metal plates, emitter plates P 1 The length is l 1 , width is w 1 , receiving plate P 2 The length is l 2 , width is w 2 , relay plate P 3 The x-axis length is l 3 , the y-axis length is w 3 ;

[0013] When there is no offset, the emitter plate P 1 , receiving plate P 2 、Relay plate P 3 Parallel, emitter plate P 1 , receiving plate P 2 The center of the projection on the xoy plane is the same as the relay plate P 3 The center of the emitter plate P 1 and receiving plate P 2 The length direction and width direction are the x-axis and the y-axis respectively.

[0014] Preferably, the transmitting circuit includes a system input DC voltage V DC , by MOS tube S 1 To S 4 The H-bridge inverter consists of an inductor L 1 and capacitor C 1 The transmitting end LC compensation circuit is composed of the receiving circuit including the inductor L 2 and capacitor C 2 The receiving end LC compensation circuit is composed of a diode D 1 To D 4 The full-bridge rectifier and filter capacitor C f and load resistance R o .

[0015] Preferably, the emitter plate P 1and receiving plate P 2 The parameters are the same, the inductor L 1 and inductor L 2 The inductance value is L, the capacitance C 1 and capacitor C 2 The capacitance value is C.

[0016] Preferably, the operating frequency of the system is set to C plus C P Minus C M The product of the result and L is negative half, C P is the self-capacitance of the transmitter in the source model equivalent to the three-plate coupling mechanism, C M It is the mutual capacitance between the transmitting end and the receiving end in the source model equivalent to the three-plate coupling mechanism.

[0017] Preferably, C M By C s1 , C s2 , C a , C 1G and C 2G Decision, C. s1 and C s2 are the stray capacitances of the system transmitter and receiver, respectively, C 1G and C 2G are the ground capacitance of the system transmitter and receiver, respectively. a The emitter plate P 1 and relay plate P 3 The capacitance C formed between pr With relay plate P 3 and receiving plate P 2 The capacitance C formed between rs Equivalent capacitance formed by series connection.

[0018] Preferably, C P By C s1 , C s2 , C a , C 1G , C 2G and C M Decide.

[0019] The wireless power transmission system based on three-pole single capacitor coupling provided by the present invention changes the original two-pole coupling mechanism of the two-pole single capacitor coupling WPT system into a three-pole coupling mechanism, that is, another metal plate is inserted into the air medium between the original two power plates (transmitter plate and receiving plate), which is called a relay plate. The three plates are kept parallel in space, and within the allowable offset range, the two power metal plates can always be completely projected on the relay plate. The circuit topology causes the emitter plate to induce charge, and the emitter plate and the relay plate form an electric field. The relay plate then causes the receiving plate to induce charge and form an electric field, thereby supplying power to the electrical equipment. According to the electric field coupling principle of the SCC-WPT system, the system achieves 100% anti-offset in the two-dimensional plane of the transceiver plate within the area of ​​the relay plate, and has the outstanding advantages of high offset tolerance and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a circuit topology diagram of a wireless power transmission system based on three-electrode single capacitor coupling provided by an embodiment of the present invention;

[0021] Figure 2 The embodiment of the present invention provides Figure 1 Equivalent circuit diagram of

[0022] Figure 3 The embodiment of the present invention provides Figure 2 Equivalent source model diagram;

[0023] Figure 4 is a position relationship diagram of the coupling mechanism when there is no offset provided by an embodiment of the present invention;

[0024] Figure 5 is a position relationship diagram of the coupling mechanism when position offset occurs provided by an embodiment of the present invention;

[0025] Figure 6 is a position relationship diagram of the coupling mechanism when an angle offset occurs provided by an embodiment of the present invention;

[0026] Figure 7 It is a schematic diagram of the fluctuation of the output power of the system provided by the embodiment of the present invention as the position of the receiving electrode plate shifts on the xoy plane;

[0027] Figure 8 is a schematic diagram showing that the system efficiency provided by an embodiment of the present invention fluctuates as the position of the receiving electrode plate shifts on the xoy plane;

[0028] Fig. 9 is a schematic diagram of the fluctuation of the output power of the system provided by the embodiment of the present invention as the receiving plate rotates on the xoy plane;

[0029] Fig.10It is a current and voltage waveform diagram of the transmitting side when the transmitting plate and the receiving plate of the system provided by the embodiment of the present invention are facing each other;

[0030] Fig.11 It is a current and voltage waveform diagram of the transmitting side when the receiving electrode plate provided by the embodiment of the present invention is offset by 15 cm on the x-axis and 15 cm on the y-axis in the xoy plane;

[0031] Fig.12 It is a current and voltage waveform diagram of the transmitting side when the receiving electrode plate provided by the embodiment of the present invention rotates 30° in the xoy plane. DETAILED DESCRIPTION

[0032] The following specifically illustrates the implementation mode of the present invention in conjunction with the accompanying drawings. The embodiments are provided for illustrative purposes only and cannot be understood as limiting the present invention. The accompanying drawings are provided for reference and illustration only and do not constitute a limitation on the scope of patent protection of the present invention, because many changes can be made to the present invention without departing from the spirit and scope of the present invention.

[0033] The wireless power transmission system based on three-electrode single capacitor coupling provided by the embodiment of the present invention is as follows: Figure 1 As shown, it includes a three-plate coupling mechanism, which includes emitter plates P arranged in sequence. 1 (or called the primary plate), relay plate P 3 (passive plate) and receiving plate P 2 (also called secondary plate or pickup plate), where the emitter plate P 1 Connect the transmitting circuit (including the system input DC voltage V DC , by MOS tube S 1 To S 4 The H-bridge inverter consists of an inductor L 1 and capacitor C 1 The transmitting end LC compensation circuit is composed of the receiving plate P 2 Connect the receiving circuit (including inductor L 2 and capacitor C 2 The receiving end LC compensation circuit is composed of a diode D 1 To D 4 The full-bridge rectifier and filter capacitor C f and load resistance R o ). The output voltage of the H-bridge inverter is expressed as The full-bridge rectifier and its subsequent circuit can be equivalent to a resistor R eq =R o ×8 / π 2 .

[0034] According to the published research results related to the single capacitor equivalent model, Figure 1 The circuit can be equivalent to Figure 2 Compared to Figure 1 , Figure 2 The emitter plate P 1 and relay plate P 3 、Relay plate P 3 and receiving plate P 2 The two capacitors C formed between pr and C rs The equivalent capacitor C is connected in series a , and will actually exist but Figure 1 Stray capacitance C not shown s1 and C s2 The two stray capacitors provide return paths for the primary and secondary circuits. 1G and C 2G Located at the emitter plate P 1 , receiving plate P 2 Between and GND. The LC compensation network remains unchanged.

[0035] C 1G and C 2G The source is two metal plates P in free space 1 and P 2 , in this example, the emitter plate P is set 1 and receiving plate P 2 The parameters are the same, then it can be calculated as:

[0036]

[0037] Among them, S is a rectangular metal plate (i.e., emitter plate P 1 Or receiving plate P 2 ) area.

[0038] In addition, according to the circuit principle, the circuit can be represented by an equivalent behavioral source model, such as Figure 3 As shown, C M Defined as the mutual capacitance between the transmitting and receiving ends of the coupling mechanism, C P Defined as the self-capacitance of the transmitting end of the coupling mechanism, C R Defined as the self-capacitance at the receiving end of the coupling mechanism, V C1 、V C2 They are respectively the capacitor C 1 , C 2 The voltage, I 1 Indicates the inductance L 1 The current, I 2 Indicates the inductance L 2 In this system, C P , C R and C M It can be deduced as:

[0039]

[0040] Among them, the C mentioned above a C pr With C rs The equivalent value of can be calculated as:

[0041]

[0042] To obtain the same resonant network and simplify the calculation, assume:

[0043]

[0044] According to Kirchhoff's voltage law (KVL) and Kirchhoff's current law (KCL), the following equation can be obtained:

[0045]

[0046] Solving the above equation, the system AC output voltage V 2 It can be calculated as:

[0047]

[0048] In order to achieve a constant voltage output that is independent of the load, based on the total reactance of the circuit being 0, the operating frequency of the system can be derived as:

[0049]

[0050] That is, the operating frequency of the system is set to C plus C P Minus C M The product of the result of multiplying L by the negative power of one half.

[0051] Combining the above formula, the output voltage V is derived 2 It can be expressed as:

[0052] V 2 =-V 1 (8)

[0053] Further from the above formula, we can get the input impedance Z in , expressed as:

[0054]

[0055] In equation (9), it can be deduced that its imaginary part is always greater than 0, that is, the total impedance is weakly inductive, thereby achieving a constant ZVS state.

[0056] Therefore, the output power P can be expressed as:

[0057]

[0058] Figure 4 The emitter plate P 1 and receiving plate P 2 There is no misalignment between the two metal plates. At this time, both metal plates are located at the relay plate P. 3 The center position of the relay plate P 3 The corner of the coordinate is the origin o, with the relay plate P 3 In the three-dimensional rectangular coordinate system established with the length, width and thickness directions of the x-axis, y-axis and z-axis respectively, it is assumed that the emitter plate P 1 The length is l 1 , width is w 1 , receiving plate P 2 The length is l 2 , width is w 2 , relay plate P 3 The x-axis length is l 3 , the y-axis length is w 3 . When there is no offset, the emitter plate P 1 , receiving plate P 2 、Relay plate P 3 Parallel, emitter plate P 1 , receiving plate P 2 The center of the projection on the xoy plane is the same as the relay plate P 3 The center of the emitter plate P 1 and receiving plate P 2 The length and width directions of are x-axis and y-axis respectively. Assume that during the charging process, the emitter plate P 1 With relay plate P 3 The maximum possible x-axis offset and y-axis offset between 13m , Δy 13m , the maximum rotation angle on the xoy plane is α 13m ; Assume that the receiving plate P 2 With relay plate P 3 The maximum possible x-axis offset and y-axis offset between 23m , Δy 23m , the maximum rotation angle on the xoy plane is α 23m , in order to realize the emitter plate P during the charging process 1 , receiving plate P 2 The projection on the xoy plane is always located at the relay plate P 3 On (i.e., the projected area is constant, the output power is constant), to achieve strong anti-deviability of the system, then the relay plate P 3 The x-axis length l 3 , y-axis length w 3Need to meet:

[0059]

[0060] Among them, Q1 to Q4 are different constraints. Constraint Q1 refers to when the emitter plate P 1 The maximum x-axis offset Δx occurs 13m The maximum angle α that occurs at the same time 13m When offset, the emitter plate P 1 The projection on the xoy plane is located at the relay plate P 3 Constraint Q2 means that when the receiving plate P 2 The maximum x-axis offset Δx occurs 23m The maximum angle α that occurs at the same time 23m When offset, the receiving plate P 2 The projection on the xoy plane is located at the relay plate P 3 Constraint Q3 means that when the emitter plate P 1 Maximum y-axis offset Δy occurs 13m The maximum angle α that occurs at the same time 13m When offset, the emitter plate P 1 The projection on the xoy plane is located at the relay plate P 3 Constraint Q4 means that when the receiving plate P 2 Maximum y-axis offset Δy occurs 23m The maximum angle α that occurs at the same time 23m When offset, the receiving plate P 2 The projection on the xoy plane is located at the relay plate P 3 superior.

[0061] The relay plate P 3 The area of ​​the relay plate P should be as small as possible on the basis of meeting the above requirements. 3 The x-axis length l 3 , y-axis length w 3 Pick:

[0062]

[0063] Among them, max(,) means taking the maximum value in the brackets, Δl 3 ,Δw 3 >0 is l 3 、w 3 The design margin shall be determined based on actual needs.

[0064] According to the above design rules, this example determines the metal plate P 1 and P 2 The length of l is the same, 1 =V l 2=l=40cm, P 1 and P 2 The width of w 1 =w 2 =w=10cm. Metal plate P 1 and P 3 The overlapping area between them is denoted as A 1 Similarly, P 2 and P 3 The corresponding area between them is A 2 Indicates that A 1 =A 2 .P 1 and P 3 (P 2 and P 3 ) are defined as d 1 (d 2 ), where d 1 =d 2 =3mm. 3 The plate has an x-axis length of 70 cm, a y-axis length of 50 cm, and a thickness of 1.5 cm.

[0065] like Figure 4 As shown, at this time, the emitter plate P 1 and receiving plate P 2 Both are located at the center plate P 3 When the power-consuming device is close to the wireless charging device, there will be lateral misalignment (x-axis displacement), longitudinal misalignment (y-axis displacement) and angular misalignment (α). Therefore, it is very important to analyze the tolerance performance of the wireless charging system.

[0066] Figure 5 This is the positional relationship of the coupling mechanism when the transmitting plate and the receiving plate are offset. Figure 5 In the figure, the projections of the emitter plate and the pickup plate on the xoy plane are parallel but offset in position, ranging from Δx: -15cm to 15cm, Δy: -20cm to 20cm, where "Δx" represents the offset of the center of the emitter plate or the pickup plate in the x-axis direction, and "Δy" represents the offset of the emitter plate or the pickup plate in the y-axis direction.

[0067] Figure 6 It is the positional relationship of the coupling mechanism when the receiving electrode plate rotates on a plane parallel to the xoy plane, where "α" represents the rotation angle of the pickup electrode.

[0068] Given the geometry of the conductors and the dielectric properties of the insulator between them, the associated capacitance C can be calculated. Its value is proportional to the overlap area A and inversely proportional to the spacing d between the plates, expressed as:

[0069]

[0070] Among them, ε 0 is the vacuum dielectric constant, ε 0 ≈8.854×10 -12 F·m -1 .

[0071] Therefore, when the x-axis and y-axis between the emitter plate and the receiver plate are not aligned, as long as A 1 and A 2 If the mutual capacitance C in equation (3) is constant, the capacitance of the capacitor formed by two parallel plates with an overlapping area of ​​A will also remain constant. In other words, the tolerance range is the entire area within P3. This is because the mutual capacitance C in equation (3) is pr and C rs Keep stable, that is, C in formula (2) and formula (6) M remains unchanged, so that the output voltage V in equation (6) 2 The output power P in equation (10) remains stable, thus achieving a higher offset tolerance.

[0072] An experimental platform is built to verify the above theoretical model. Figure 7 and Figure 8 The fluctuation of the system output power and efficiency in response to Δx from -15cm to 15cm and Δy from -20cm to 20cm is shown. At the same time, the experimental results of the pickup plate rotating at any angle in the xoy plane are shown in Fig. 9 As shown. Figure 7 , Figure 8 , Fig. 9 As shown in the figure, the output power has been hovering around 33.2W, while the efficiency is generally maintained at 52.3%. These results show that the output power and efficiency remain basically stable, thus confirming that the added relay plate makes the system have strong anti-drift capability.

[0073] Fig.10 The electrical waveform of the transmitting side when the transmitting side plate and the receiving side plate are not offset and the center is aligned in the actual system is shown; Fig.11 It is the electrical waveform on the transmitting side when the receiving side plate and the transmitting side plate have a large relative position offset; Fig.12 It is the electrical waveform of the transmitting side when the receiving side plate rotates at a certain angle. Obviously, in the above three cases, the system has achieved zero voltage switching (ZVS) very well.

[0074] As an application example, the system is applied to wireless charging of drones, and a receiving plate P is installed at the bottom of the drone. 2 The surface of the UAV power supply platform is the relay plate P 3, emitter plate P 1 Located inside the power supply platform, the relay plate P 3 When the drone lands on the power supply platform, the drone receives the power from the plate P 2 , platform surface relay plate P 3 , the internal emitter plate P of the platform 1 When the UAV is landing, it will be affected by the external environment and its relative position will be offset in the plane relative to the power supply platform (such as Figure 5 ), there will also be an angular offset (such as Figure 6 ), the system using the three-pole plate coupling mechanism can well overcome the above-mentioned offset.

[0075] In summary, the wireless power transmission system based on three-plate single capacitor coupling provided by the embodiment of the present invention changes the original two-plate coupling mechanism of the two-plate single capacitor coupling WPT system into a three-plate coupling mechanism, that is, inserting another metal plate in the air medium between the original two power plates (transmitter plate and receiving plate), called the relay plate, and the three plates are kept parallel in space, and within the allowable offset range, the two power metal plates can always be completely projected on the relay plate. The circuit topology causes the emitter plate to induce a charge, and the emitter plate and the relay plate form an electric field, and then the relay plate causes the receiving plate to induce a charge and form an electric field, and then supply power to the electrical equipment. By designing the sizes of the emitter plate, the relay plate and the receiving plate, according to the electric field coupling principle of the SCC-WPT system, the system achieves 100% anti-offset in the two-dimensional plane of the transceiver plate within the area of ​​the relay plate, and has the outstanding advantages of high offset tolerance and low cost.

[0076] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A wireless power transmission system based on three-electrode single capacitor coupling, characterized in that: It includes a three-plate coupling mechanism; the three-plate coupling mechanism includes an emitter plate P1, a relay plate P3 and a receiving plate P2 arranged in sequence, wherein the emitter plate P1 is connected to the transmitting circuit, the receiving plate P2 is connected to the receiving circuit, and the relay plate P3 is not connected; the parameters of the emitter plate P1, the receiving plate P2 and the relay plate P3 satisfy: within the offset range, the projection area of ​​the emitter plate P1 and the receiving plate P2 on the relay plate P3 is the area of ​​the emitter plate P1 and the receiving plate P2.

2. The wireless power transmission system based on three-electrode single capacitor coupling according to claim 1 is characterized in that: The relay plate P3 is a rectangular metal plate. With one corner of the relay plate P3 as the coordinate origin o, a three-dimensional rectangular coordinate system is established with the length, width and thickness directions of the relay plate P3 as the x-axis, y-axis and z-axis respectively. The size of the relay plate P3 satisfies: When the emitter plate P1 has the maximum x-axis offset Δx 13m The maximum angle α that occurs at the same time 13m When offset, the projection of the emitter plate P1 on the xoy plane is located on the relay plate P3; When the receiving plate P2 has the maximum x-axis offset Δx 23m The maximum angle α that occurs at the same time 23m When offset, the projection of the receiving plate P2 on the xoy plane is located on the relay plate P3; When the emitter plate P1 has the maximum y-axis offset Δy 13m The maximum angle α that occurs at the same time 13m When offset, the projection of the emitter plate P1 on the xoy plane is located on the relay plate P3; When the receiving plate P2 has the maximum y-axis offset Δy 23m The maximum angle α that occurs at the same time 23m When offset, the projection of the receiving plate P2 on the xoy plane is located on the relay plate P3.

3. The wireless power transmission system based on three-electrode single capacitor coupling according to claim 2 is characterized in that: The emitter plate P1 and the receiving plate P2 are both rectangular metal plates. The length of the emitter plate P1 is l1 and the width is w1. The length of the receiving plate P2 is l2 and the width is w2. The length of the relay plate P3 in the x-axis direction is l3 and the length in the y-axis direction is w3. When there is no offset, the emitter plate P1, the receiving plate P2, and the relay plate P3 are parallel, the centers of the projections of the emitter plate P1 and the receiving plate P2 on the xoy plane coincide with the center of the relay plate P3, and the length direction and width direction of the emitter plate P1 and the receiving plate P2 are the x-axis and the y-axis respectively.

4. The wireless power transmission system based on three-electrode single capacitor coupling according to claim 3 is characterized in that: The transmitting circuit includes a system input DC voltage V DC , an H-bridge inverter composed of MOS tubes S1 to S4, a transmitter LC compensation circuit composed of inductor L1 and capacitor C1; the receiving circuit includes a receiving end LC compensation circuit composed of inductor L2 and capacitor C2, a full-bridge rectifier composed of diodes D1 to D4, and a filter capacitor C f and load resistance R o .

5. The wireless power transmission system based on three-electrode single capacitor coupling according to claim 4 is characterized in that: The parameters of the emitter plate P1 and the receiving plate P2 are the same, the inductance values ​​of the inductor L1 and the inductor L2 are both L, and the capacitance values ​​of the capacitor C1 and the capacitor C2 are both C.

6. The wireless power transmission system based on three-electrode single capacitor coupling according to claim 5 is characterized in that: The system's operating frequency is set to C plus C P Minus C M The product of the result and L is negative half, C P is the self-capacitance of the transmitter in the source model equivalent to the three-plate coupling mechanism, C M It is the mutual capacitance between the transmitting end and the receiving end in the source model equivalent to the three-plate coupling mechanism.

7. The wireless power transmission system based on three-electrode single capacitor coupling according to claim 6 is characterized in that: C M By C s1 , C s2 , C a , C 1G and C 2G Decision, C. s1 and C s2 are the stray capacitances of the system transmitter and receiver, respectively, C 1G and C 2G are the ground capacitance of the system transmitter and receiver, respectively. a The capacitance C formed between the emitter plate P1 and the relay plate P3 pr The capacitor C formed between the relay plate P3 and the receiving plate P2 rs Equivalent capacitance formed by series connection.

8. The wireless power transmission system based on three-electrode single capacitor coupling according to claim 7 is characterized in that: C P By C s1 , C s2 , C a , C 1G , C 2G and C M Decide.

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