CN112003384B - Electron Periodic Reciprocating Flow Method for Electric Field Coupled Wireless Power Transmission System - Google Patents

Abstract

The invention discloses an electronic periodic reciprocating flow method of an electric field coupling type wireless electric energy transmission system, which comprises the steps of firstly establishing a topological structure of the electric field coupling type wireless electric energy transmission system with double coupling polar plates; then, assuming that the current direction is changed only once in a half switching period, and finishing the forward flow of current from the primary side of the system to the secondary side of the system in the last half switching period, wherein the coupling capacitor is an isolation unit; in the next half of the switching period, finishing the reverse flow of current from the secondary side of the system to the primary side of the system, wherein the coupling capacitor is an isolation unit; and a closed loop circuit is formed in one period, so that the electric energy is transferred from the primary side of the system to the secondary side of the system, and the periodic reciprocating flow of electrons is formed. The invention solves the problems that the electric field coupling type wireless power transmission system in the prior art can only work in a closed-loop circuit and electrons can only flow in a complete circuit closed loop.

Description

Electron Periodic Reciprocating Flow Method for Electric Field Coupled Wireless Power Transmission System

technical field

The invention belongs to the technical field of wireless power transmission, and in particular relates to an electronic periodic reciprocating flow method of an electric field coupled wireless power transmission system.

Background technique

Wireless power transfer is a technology that enables power transfer without physical contact. There are many methods of wireless power transfer, including magnetic field coupling-based wireless power transfer, electric field coupling-based wireless power transfer, laser-based optical power transfer, and far-field RF microwave power transfer. The magnetic field coupling wireless power transfer system uses the non-radiative magnetic field in the frequency range of kHz-MHz to realize the function of wireless power transfer, and the coupled inductor is used to generate the magnetic field. Magnetic field coupled wireless power transfer systems have been widely used in underwater devices, implantable medical devices, mobile devices, electric vehicles and drones. When applied in the air medium, the magnetic field coupled wireless power transfer technology has the advantages of high efficiency, galvanic isolation and high reliability.

In the seawater environment, the underwater magnetic field coupled wireless power transmission system will generate eddy current loss in the conductive seawater, and the mutual inductance between the inductor coils will change with the seawater conductivity, and the seawater conductivity will change with the seawater. changes in temperature and salinity. The underwater magnetic field coupled wireless power transmission system will be affected by the seawater pressure at the same time to produce a "piezomagnetic effect". In addition, the underwater magnetic field coupled wireless power transmission system is also very sensitive to nearby metal materials, which will produce The excess heat is accompanied by a large amount of energy loss.

Compared with the magnetic field coupled wireless power transfer system, the electric field coupled wireless power transfer system uses a very high frequency (MHz) electric field to transfer power from the transmitter to the receiver. The coupling plate at the transmitting end and the coupling plate at the receiving end together form a coupling capacitor mechanism. In general, electric field-coupled wireless power transfer systems are often used in low-power applications. In recent years, electric field-coupled wireless power transmission systems have begun to be applied to wireless power transmission with a power level of several kilowatts and a transmission distance of tens of centimeters. Electric field-coupled wireless power transfer system technology is highly developed, and this technology can also be used in electric vehicles and all-electric aircraft.

Since the dielectric constant of seawater is about 81 times that of free space or air, in seawater medium, the ability of electric field coupled wireless power transfer system to transmit power under sea will be greatly enhanced. In conductive seawater, the electric field-coupled wireless power transmission system has the advantages of simple system structure, no eddy current loss, etc., and is not affected by surrounding metals during operation. In addition, only the metal plate is used as the medium for wireless power transmission, which can greatly reduce the cost. Therefore, the electric field coupled wireless power transmission system will have a bright application prospect in the wireless power transmission under the sea. However, the electric field-coupled wireless power transfer system can only work in a closed-loop circuit, and electrons can only flow in a complete closed-loop circuit. There is no article or report that proposes how to use the electric field coupled wireless power transfer system based on double-coupling plates to realize the application of underwater wireless power transfer. The periodic reciprocating flow method of electrons will provide a new idea for the application of electric field-coupled wireless power transfer systems under the sea.

In this context, the patent of the present invention proposes a periodic reciprocating flow theory of electrons in an electric field coupled underwater wireless power transmission system.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a periodic reciprocating flow method of electrons in an electric field coupling wireless power transmission system, which solves the problem that the electric field coupling wireless power transmission system existing in the prior art can only work in a closed-loop circuit, and the electrons can only The problem of flow in a complete circuit closed loop.

The technical scheme adopted by the present invention is that the electronic periodic reciprocating flow method of the electric field coupled wireless power transmission system is specifically implemented according to the following steps:

Step 1. Establish a topology structure of a double-coupling plate electric field-coupled wireless power transmission system;

Step 2. Assuming that the current direction changes only once in the half switching cycle, in the first half switching cycle, the primary current I _1F flows from the power supply V _in to the inductor L ₁ and the coupling plate P ₁ ; at the same time, on the secondary side of the system , the current I _2F flows from the coupling plate P ₂ and the inductor L ₂ to the output filter capacitor C _o and the load. In the first half of the switching cycle, the current flows from the primary side of the system to the secondary side of the system. The coupling capacitor is an isolation unit;

Step 3. In the second half of the switching cycle, the primary current I _1S of the system flows from the coupling plate P ₁ and the inductor L ₁ to the ground G ₁ , and at the secondary side of the system, the current I _2S flows from the inductor L ₂ to the coupling plate P ₂ , in the second half of the switching cycle, the reverse flow of current from the secondary side of the system to the primary side of the system is completed, and the coupling capacitor is the isolation unit;

Step 4. In the conductive medium, the double-coupling plate electric field-coupled wireless power transmission system uses the coupling capacitor as an isolation unit to form a closed-loop circuit in one cycle. The transfer of edges, thus, forms a periodic back-and-forth flow of electrons.

The present invention is also characterized in that,

In step 1, the topological structure of the double-coupling-pole electric field-coupled wireless power transmission system is specifically: including the coupling pole plate P ₁ and the coupling pole plate P ₂ , and a conductive medium is filled between the coupling pole plate P ₁ and the coupling pole plate P ₂ , The coupling plate P ₁ is connected to the input side of the system after being connected in series with the inductor L _1. The input side of the system includes the switch tube S ₁ and the switch tube S ₂ connected _{in parallel with the power supply V in in} the form of their own series connection, and the switch coupling plate P ₂ is connected to the inductor. L ₂ is connected in series to the output side of the system, and the output side of the system includes diode D ₁ and diode D ₂ connected in parallel with the output filter capacitor C _o and the load in the form of their own series connection.

The conductive medium filled between the coupling plate P ₁ and the coupling plate P ₂ is seawater.

Step 2 is as follows:

Under seawater conditions, the dielectric constant, temperature, salt concentration and angular frequency of electromagnetic waves of seawater conductive medium are related as follows:

Among them, ε _sea (S, T, ω) is the dielectric constant of seawater conducting medium, ε _∞ (S, T) is the seawater dielectric constant when the frequency is infinite, ε ₀ is the dielectric constant of free space, ε ₀ =8.854×10 ^-12 Fm ^-1 , ω=2πf, f is the frequency of electromagnetic waves, ε _S (S, T) is the static permittivity of seawater, δ(S, T) is the ionic conductivity of seawater, τ( S, T) is the Debye relaxation time; S is the seawater salinity, T is the seawater temperature;

In seawater medium, the capacitance C composed of two coupled plates is expressed as:

Among them, l represents the length of the coupling plate, and d represents the distance between the transmitting-end coupling plate and the receiving-end coupling plate;

In the double-coupling plate electric field-coupled wireless power transmission system, the coupling capacitance C _M is expressed as:

C _M = C (3)

Through the half-bridge inverter circuit, the resonant voltage v _P of the primary side is:

Through the half-bridge rectifier circuit, the resonant voltage v _S of the secondary side and the load voltage v ₀ have the following relationship:

In the first half of the switching cycle, based on Kirchhoff's current law KCL and Kirchhoff's voltage law KVL principles, the primary current i _1F and the secondary current i _2F are expressed as:

Among them, v _in is the input voltage, v _L1 is the voltage of the inductor L ₁ , u _P1 is the voltage of the coupling plate P ₁ , L ₁ is the inductance value of the inductor L ₁ , u _P2 is the voltage of the coupling plate P ₂ , v _L2 is the voltage of the inductor L ₂ , v ₀ is the output voltage of the electric field-coupled wireless power transmission system, R _L is the load resistance value, L ₂ is the inductance value of the inductor L ₂ , C ₀ is the output filter capacitor C _o The capacitance value, ω _S = 2πf _S , f _S is the switching frequency;

During the first half switching cycle, the current i _CF of the coupling capacitor is expressed as:

Among them, C is the equivalent capacitance value of the coupling capacitor.

Step 3 is as follows:

In the second half of the switching cycle, based on Kirchhoff's current law KCL and Kirchhoff's voltage law KVL, the primary side current i _1S and the secondary side current i _2S are expressed as:

During the second half of the switching cycle, the current i _CS of the coupling capacitor is expressed as:

Step 4 is as follows:

In one switching cycle, the charge and discharge of the coupling capacitors are kept in balance, which is expressed as:

Among them, I _CF is the charging current of the coupling capacitor in the first half of the switching period, and I _CS is the discharge current of the coupling capacitor in the second half of the switching period;

In one switching cycle, the coupling capacitor is equivalent to completing one charge and discharge, and the current flows back and forth in the system twice, thus completing the transfer of electrical energy from the primary side to the secondary side of the electric field coupled wireless power transfer system.

The beneficial effects of the present invention are that (1) the electric field coupled underwater wireless power transmission system of the present invention has no eddy current loss and is insensitive to the existence of surrounding metals, it is very suitable for underwater wireless charging scenarios, and can achieve high power and high efficiency (2) In a dynamic underwater environment, stable and isolated charging can be performed for underwater equipment. By using the double-coupling-pole electric field-coupled wireless power transfer system based on the seawater medium, combined with the periodic reciprocating flow theory of electrons in the new electric field-coupled wireless power transfer system proposed in the present invention, stable and convenient underwater wireless power is realized (3) The electric field-coupled underwater wireless power transmission system can only use metal plates to charge the underwater equipment, which can greatly reduce the cost of underwater wireless power transmission; The proposed new theory of the periodic reciprocating flow of electrons in the electric field coupled wireless power transfer system can provide a new solution for the application of the electric field coupled wireless power transfer system under the sea.

Description of drawings

Fig. 1 is a kind of double-coupling polar plate electric field coupling type wireless power transmission system topology related to the present invention;

Figure 2 (a) schematic diagram of electron flow in the first half switching cycle of the double-coupling plate electric field-coupled wireless power transmission system involved in the present invention;

Fig. 2 (b) is the equivalent circuit diagram of the first half switching cycle of the double-coupling plate electric field coupling wireless power transmission system involved in the present invention;

Figure 3 (a) is a schematic diagram of the electron flow in the second half of the switching cycle of the double-coupling plate electric field-coupled wireless power transmission system involved in the present invention;

Fig. 3 (b) is the equivalent circuit diagram of the second half switching cycle of the double-coupling plate electric field coupling wireless power transmission system involved in the present invention;

Figure 4 (a) is a schematic diagram of electron flow in a double-coupling-pole electric field-coupled wireless power transmission system in a conductive medium, when the voltage of the coupling plate P1 is greater _than the voltage of the coupling plate P2 _;

Figure 4(b) is a schematic diagram of electron flow in a double-coupling-plate electric field _- coupled wireless power transfer system when the voltage of the coupling plate P1 is less _than the voltage of the coupling plate P2 in a conductive medium.

Detailed ways

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

The periodic reciprocating flow method of electrons in the electric field coupling wireless power transmission system of the present invention is specifically implemented according to the following steps:

Step 1. Establish a topology structure of a double-coupling plate electric field-coupled wireless power transmission system;

As shown in FIG. 1 , the topological structure of the double-coupling plate electric field coupling wireless power transmission system in step 1 is specifically: including the coupling plate P ₁ and the coupling plate P ₂ , and the coupling plate P ₁ and the coupling plate P ₂ The space is filled with a conductive medium, and the coupling plate P ₁ is connected to the input side of the system after being connected in series with the inductor L _1. The input side of the system includes the switch tube S ₁ and the switch tube S ₂ connected _{in parallel with the power supply V in in} the form of their own series connection, and the switch is coupled to The pole plate P ₂ is connected in series with the inductor L ₂ to the system output side. The system output side includes diodes D ₁ and D ₂ connected in parallel with the output filter capacitor C _o and the load in the form of their own series connection.

The conductive medium filled between the coupling plate P ₁ and the coupling plate P ₂ is seawater.

Step 2. Assuming that the current direction changes only once in the half switching cycle, in the first half switching cycle, the primary current I _1F flows from the power supply V _in to the inductor L ₁ and the coupling plate P ₁ ; at the same time, on the secondary side of the system , the current I _2F flows from the coupling plate P ₂ and the inductor L ₂ to the output filter capacitor C _o and the load. In the first half of the switching cycle, the current flows from the primary side of the system to the secondary side of the system. The coupling capacitor is an isolation unit;

Step 2 is as follows:

Under seawater conditions, the dielectric constant, temperature, salt concentration and angular frequency of electromagnetic waves of seawater conductive medium are related as follows:

Among them, ε _sea (S, T, ω) is the dielectric constant of seawater conducting medium, ε _∞ (S, T) is the seawater dielectric constant when the frequency is infinite, ε ₀ is the dielectric constant of free space, ε ₀ =8.854×10 ^-12 Fm ^-1 , ω=2πf, f is the frequency of electromagnetic waves, ε _S (S, T) is the static permittivity of seawater, δ(S, T) is the ionic conductivity of seawater, τ( S, T) is the Debye relaxation time; S is the seawater salinity, T is the seawater temperature;

In seawater medium, the capacitance C composed of two coupled plates is expressed as:

Among them, l represents the length of the coupling plate, and d represents the distance between the transmitting-end coupling plate and the receiving-end coupling plate;

In the double-coupling plate electric field-coupled wireless power transmission system, the coupling capacitance C _M is expressed as:

C _M = C (3)

Through the half-bridge inverter circuit, the resonant voltage v _P of the primary side is:

Through the half-bridge rectifier circuit, the resonant voltage v _S of the secondary side and the load voltage v ₀ have the following relationship:

In the first half of the switching cycle, based on Kirchhoff's current law KCL and Kirchhoff's voltage law KVL principles, the primary current i _1F and the secondary current i _2F are expressed as:

Among them, v _in is the input voltage, v _L1 is the voltage of the inductor L ₁ , u _P1 is the voltage of the coupling plate P ₁ , L ₁ is the inductance value of the inductor L ₁ , u _P2 is the voltage of the coupling plate P ₂ , v _L2 is the voltage of the inductor L ₂ , v ₀ is the output voltage of the electric field-coupled wireless power transmission system, R _L is the load resistance value, L ₂ is the inductance value of the inductor L ₂ , C ₀ is the output filter capacitor C _o The capacitance value, ω _S = 2πf _S , f _S is the switching frequency;

During the first half switching cycle, the current i _CF of the coupling capacitor is expressed as:

Among them, C is the equivalent capacitance value of the coupling capacitor.

Step 3. In the second half of the switching cycle, the primary current I _1S of the system flows from the coupling plate P ₁ and the inductor L ₁ to the ground G ₁ , and at the secondary side of the system, the current I _2S flows from the inductor L ₂ to the coupling plate P ₂ , in the second half of the switching cycle, the reverse flow of current from the secondary side of the system to the primary side of the system is completed, and the coupling capacitor is the isolation unit;

Step 3 is as follows:

In the second half of the switching cycle, based on Kirchhoff's current law KCL and Kirchhoff's voltage law KVL, the primary side current i _1S and the secondary side current i _2S are expressed as:

In the second half of the switching cycle, the current i _CS of the coupling capacitor is expressed as:

Step 4. In the conductive medium, the double-coupling plate electric field-coupled wireless power transmission system uses the coupling capacitor as an isolation unit to form a closed-loop circuit in one cycle. The transfer of edges, thus, forms a periodic back-and-forth flow of electrons.

Step 4 is as follows:

In one switching cycle, the charge and discharge of the coupling capacitors are kept in balance, which is expressed as:

Among them, I _CF is the charging current of the coupling capacitor in the first half of the switching period, and I _CS is the discharge current of the coupling capacitor in the second half of the switching period;

In one switching cycle, the coupling capacitor is equivalent to completing one charge and discharge, and the current flows back and forth in the system twice, thereby completing the transfer of electrical energy from the primary side to the secondary side of the electric field coupled wireless power transfer system.

The conventional electric field coupling wireless power transmission system adopts a four-coupling-pole-plate coupling-capacitor mechanism or a six-coupling-pole-plate coupling-capacitance mechanism. Wireless power transfer simplifies the coupling capacitor mechanism, improves the system power density and the cost of the wireless power transfer system. The double-coupling-pole electric field-coupled wireless power transmission system involved in the present invention is convenient for the application of wireless power transmission under water.

Figure 1 shows the topology of an electric field-coupled wireless power transfer system based on double-coupling plates. V _in is the input power supply, the switch tube S ₁ and the switch tube S ₂ form a half-bridge inverter circuit, the inductor L ₁ and the inductor L ₂ are the primary side resonance compensation unit and the secondary side resonance compensation unit respectively, the coupling plate P ₁ and the coupling Plate P ₂ forms a coupling capacitor unit, diode D ₁ and diode D ₂ form a diode-based half-bridge rectifier circuit, capacitor C _o is an output filter capacitor, and the load unit can be a battery or a resistor.

Figure 2(a) shows a schematic diagram of the electron flow in the first half of the switching cycle of the double-coupling plate electric field-coupled wireless power transfer system. When the switch S1 is turned _on and the switch S2 is turned off, the primary current _{I 1F} flows from the power source V _in to the inductor L ₁ and the coupling capacitor unit. The secondary side current I _2F flows from the coupling capacitor unit to the inductor L ₂ , the filter capacitor C _o and the load.

Figure 2(b) shows the equivalent circuit diagram of the second half switching cycle of the double-coupling plate electric field-coupled wireless power transmission system. When the switch tube S2 is turned _on and the switch tube S1 is turned off, the inductance L1 can be equivalent to the form _{of a} power supply V _L1 and a resistor R _L1 , the voltage at the end of the coupling plate P ₁ is U _P1 , and the coupling plate P ₂ The voltage at the terminal is U _P2 , the inductor L ₂ can be equivalent to the form of a power supply _{VL2 and a resistor R L2 ,} and the resistance of the output terminal is the equivalent parallel resistance of the resistor R _Co of the output filter capacitor C _o and the load resistor R _L.

Figure 3(a) shows a schematic diagram of the electron flow in the second half of the switching cycle of the double-coupling plate electric field-coupled wireless power transfer system. When the switch S2 is turned _on and the switch S1 is turned off, the primary current _{I 1S} flows from the coupling capacitor to the inductor L ₁ and the primary ground. The secondary current I _2S flows from the inductor L ₂ to the coupling capacitor. During this period, the filter capacitor C _o continues to supply power to the load.

Figure 3(b) shows the equivalent circuit diagram of the second half of the switching cycle of the double-coupling plate electric field-coupled wireless power transmission system. When the switch tube S2 is turned _on and the switch tube S1 is turned off, the inductance L1 can be equivalent to the form _{of a} power supply V _L1 and a resistor R _L1 , the voltage at the end of the coupling plate P ₁ is U _P1 , and the coupling plate P ₂ The voltage at the terminal is U _P2 , the inductor L ₂ can be equivalent to the form of a power supply _{VL2 and a resistor R L2 ,} and the resistance of the output terminal is the equivalent parallel resistance of the resistor R _Co of the output filter capacitor C _o and the load resistor R _L.

Figure 4(a) shows that in the conductive medium, in the first half of the switching cycle, when the voltage of the coupling plate P1 is greater _than the voltage of the coupling plate P2, the electrons flow in the _double -coupling plate electric field-coupled wireless power transfer system Schematic. When the voltage _on the coupling plate P1 is greater _than the voltage _on the coupling plate P2, the electrons in the primary wire flow to the direction away from the coupling plate P1. Electrons in the secondary wire flow toward the coupling plate _P2 . The electrons in the conductive medium between the coupling plate P ₁ and the coupling plate P ₂ flow from the coupling plate P ₂ to the direction of the coupling plate P ₁ .

Figure 4(b) shows that in the conductive medium, in the _second half of the switching cycle, when the voltage of the coupling plate P1 is less _than the voltage of the coupling plate P2, the electrons flow in the double-coupling plate electric field-coupled wireless power transfer system Schematic. When the voltage _on the coupling plate P1 is lower _than the voltage _on the coupling plate P2, the electrons in the primary wire flow toward the direction close to the coupling plate P1. Electrons in the secondary wire flow away from the coupling plate _P2 . Electrons in the conductive medium between the coupling plate _P1 and the coupling plate _P2 flow from the coupling plate _P1 to the coupling plate _P2 .

The present invention proposes a periodic reciprocating flow method of electrons in an electric field coupling wireless power transmission system and is applied to the electric field coupling wireless power transmission system, so as to solve the problem that the electric field coupling wireless power transmission system existing in the prior art can only work in In a closed-loop circuit, and electrons can only flow in a complete closed-loop circuit. Based on the periodic reciprocating flow method of electrons, the wireless power transmission of the double-coupling plate electric field-coupled wireless power transmission system is realized. The wireless power transmission method involved in the present invention can be applied to the environment of the conductive medium, such as the underwater environment, the kerosene medium environment, and the like.

The electric field coupled underwater wireless power transmission system involved in the present invention has no eddy current loss and is insensitive to the existence of surrounding metals, which is very suitable for underwater wireless charging scenarios, and can operate with high power and high efficiency; In the environment, stable and isolated charging of underwater equipment can be carried out. The stable and convenient underwater application of the double-coupling-pole electric-field-coupled wireless power transmission system is realized through the electronic periodic reciprocating flow theory proposed in the present invention; the electric-field-coupled underwater wireless power transmission system can realize the The charging of underwater equipment can greatly reduce the cost of underwater wireless power transmission; the new electric field coupled wireless power transmission system proposed by the present invention is the periodic reciprocating flow theory of electrons, which can be an electric field coupled wireless The application of energy transmission systems under the sea provides a new solution.

Claims (3)

1. The periodic reciprocating flow method of electrons in an electric field coupling type wireless power transmission system is characterized in that, it is specifically implemented according to the following steps: Step 1. Establish a topology structure of a double-coupling plate electric field-coupled wireless power transmission system; In the step 1, the topological structure of the double-coupling pole-plate electric field-coupled wireless power transmission system is specifically: including the coupling pole plate P ₁ and the coupling pole plate P ₂ , and the coupling pole plate P ₁ and the coupling pole plate P ₂ are filled with conductive materials. Medium, the coupling plate P ₁ is connected to the input side of the system after being connected in series with the inductor L _1. The input side of the system includes the switch tube S ₁ and the switch tube S ₂ connected _{in parallel with the power supply V in in} the form of their own series connection, and the switch coupling plate P ₂ It is connected in series with the inductor L ₂ and then connected to the output side of the system. The output side of the system includes a diode D ₁ and a diode D ₂ that are connected in parallel with the output filter capacitor C _o and the load in the form of their own series connection; The conductive medium filled between the coupling pole plate P ₁ and the coupling pole plate P ₂ is seawater; Step 2. Assuming that the current direction changes only once in the half switching cycle, in the first half switching cycle, the primary current I _1F flows from the power supply V _in to the inductor L ₁ and the coupling plate P ₁ ; at the same time, on the secondary side of the system , the current I _2F flows from the coupling plate P ₂ and the inductor L ₂ to the output filter capacitor C _o and the load. In the first half of the switching cycle, the current flows from the primary side of the system to the secondary side of the system. The coupling capacitor is an isolation unit; The step 2 is as follows: Under seawater conditions, the dielectric constant, temperature, salt concentration and angular frequency of electromagnetic waves of seawater conductive medium are related as follows:

Among them, ε _sea (S, T, ω) is the dielectric constant of seawater conducting medium, ε _∞ (S, T) is the seawater dielectric constant when the frequency is infinite, ε ₀ is the dielectric constant of free space, ε ₀ =8.854×10 ^-12 Fm ^-1 , ω=2πf, f is the frequency of electromagnetic waves, ε _S (S, T) is the static permittivity of seawater, δ(S, T) is the ionic conductivity of seawater, τ( S, T) is the Debye relaxation time; S is the seawater salinity, and T is the seawater temperature; In seawater medium, the capacitance C composed of two coupled plates is expressed as:

Among them, l represents the length of the coupling plate, and d represents the distance between the transmitting-end coupling plate and the receiving-end coupling plate; In the double-coupling plate electric field-coupled wireless power transmission system, the coupling capacitance C _M is expressed as: C _M = C (3) Through the half-bridge inverter circuit, the resonant voltage v _P of the primary side is:

Through the half-bridge rectifier circuit, the resonant voltage v _S of the secondary side and the load voltage v ₀ have the following relationship:

In the first half of the switching cycle, based on Kirchhoff's current law KCL and Kirchhoff's voltage law KVL principles, the primary current i _1F and the secondary current i _2F are expressed as:

Among them, v _in is the input voltage, v _L1 is the voltage of the inductor L ₁ , u _P1 is the voltage of the coupling plate P ₁ , L ₁ is the inductance value of the inductor L ₁ , u _P2 is the voltage of the coupling plate P ₂ , v _L2 is the voltage of the inductor L ₂ , v ₀ is the output voltage of the electric field-coupled wireless power transmission system, R _L is the load resistance value, L ₂ is the inductance value of the inductor L ₂ , C ₀ is the output filter capacitor C _o The capacitance value, ω _S = 2πf _S , f _S is the switching frequency; During the first half switching cycle, the current i _CF of the coupling capacitor is expressed as:

Among them, C is the equivalent capacitance value of the coupling capacitor; Step 3. In the second half of the switching cycle, the primary current I _1S of the system flows from the coupling plate P ₁ and the inductor L ₁ to the ground G ₁ , and at the same time, on the secondary side of the system, the current I _2S flows from the inductor L ₂ to the coupling plate P ₂ , in the second half of the switching cycle, the reverse flow of current from the secondary side of the system to the primary side of the system is completed, and the coupling capacitor is the isolation unit; Step 4. In the conductive medium, the double-coupling plate electric field-coupled wireless power transmission system uses the coupling capacitor as an isolation unit to form a closed-loop circuit in one cycle. The transfer of edges, thus, forms a periodic back-and-forth flow of electrons. 2. The method for periodic reciprocating flow of electrons in an electric field coupled wireless power transmission system according to claim 1, wherein the step 3 is specifically as follows: In the second half of the switching cycle, based on Kirchhoff's current law KCL and Kirchhoff's voltage law KVL, the primary side current i _1S and the secondary side current i _2S are expressed as:

During the second half of the switching cycle, the current i _CS of the coupling capacitor is expressed as:

3. The method for periodic reciprocating flow of electrons in an electric field coupled wireless power transmission system according to claim 2, wherein the step 4 is specifically as follows: In one switching cycle, the charge and discharge of the coupling capacitors are kept in balance, which is expressed as:

Among them, I _CF is the charging current of the coupling capacitor in the first half of the switching period, and I _CS is the discharge current of the coupling capacitor in the second half of the switching period; In one switching cycle, the coupling capacitor is equivalent to completing one charge and discharge, and the current flows back and forth in the system twice, thereby completing the transfer of electrical energy from the primary side to the secondary side of the electric field coupled wireless power transfer system.

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