A low-radiation electric field coupler and its compensation circuit design method

Abstract

The present invention provides a low-radiation electric field coupler, characterized in that the primary high-voltage plate is wrapped by the secondary low-voltage plate, and the secondary low-voltage plate forms an electrostatic shielding effect on the high-voltage radiation generated by the primary high-voltage plate; the secondary high-voltage plate is wrapped by the primary low-voltage plate, and the primary low-voltage plate forms an electrostatic shielding effect on the high-voltage radiation generated by the secondary high-voltage plate. Another technical solution of the present invention is to provide a compensation circuit design method for the above-mentioned electric field coupler. The present invention wraps the high-voltage plate with a low-voltage plate, which can form an electrostatic shielding effect, isolate it from the external environment, and greatly reduce the radiation intensity. At the same time, the present invention designs a new compensation circuit based on the equivalent six-capacitor model in the design of the compensation circuit, that is, resonant compensation is performed on the equivalent six-capacitor model, and ultimately only cross-mutual capacitance with relatively small capacitance is left, which greatly simplifies the analysis of the circuit.

Description

Technical Field

[0001] The invention relates to an electric field coupler and a design method of a compensation circuit of the electric field coupler. Background Art

[0002] Wireless charging technology based on magnetic field coupling is the most commercially successful technology. Based on electromagnetic duality, couplers utilizing electric fields can also be used for wireless energy transmission in specific scenarios. It is worth noting that electric field couplers in wireless charging systems do not require the use of magnetic materials, significantly reducing system weight and cost. Furthermore, when metal objects are present, the electric field of the electric field coupler does not generate eddy current losses, significantly impacting transmission efficiency. Therefore, wireless charging systems based on electric field couplers still have great potential for development.

[0003] The electric field coupler can use a traditional horizontal quadrupole structure, including a primary high-voltage plate, a primary low-voltage plate, a secondary high-voltage plate, and a secondary low-voltage plate. The primary and secondary high-voltage plates are directly connected to the outside world, and the high voltages present on these plates can cause relatively high levels of radiation to the outside world, posing a significant safety risk. Summary of the Invention

[0004] The technical problem to be solved by the present invention is that in the existing electromagnetic coupler adopting a horizontal quadrupole plate structure, when a large excitation voltage appears on the plate, a serious radiation problem will occur.

[0005] In order to solve the above technical problems, a technical solution of the present invention is to provide a low-radiation electric field coupler, including a primary high-voltage plate, a primary low-voltage plate, a secondary high-voltage plate and a secondary low-voltage plate, the secondary low-voltage plate is grounded, and the voltage on the primary low-voltage plate is close to 0. It is characterized in that the primary high-voltage plate is wrapped by the secondary low-voltage plate, and the secondary low-voltage plate forms an electrostatic shielding effect on the high-voltage radiation generated by the primary high-voltage plate; the secondary high-voltage plate is wrapped by the primary low-voltage plate, and the primary low-voltage plate forms an electrostatic shielding effect on the high-voltage radiation generated by the secondary high-voltage plate.

[0006] Another technical solution of the present invention is to provide a compensation circuit design method for the above-mentioned electric field coupler, characterized in that it includes the following steps:

[0007] The above-mentioned electric field coupler is equivalent to an equivalent six-capacitor model consisting of an equivalent self-capacitance 1 formed by the primary high-voltage plate and the secondary low-voltage plate, an equivalent self-capacitance 2 formed by the primary low-voltage plate and the secondary high-voltage plate, an equivalent mutual capacitance 1 formed by the primary high-voltage plate and the primary low-voltage plate, an equivalent mutual capacitance 2 formed by the secondary high-voltage plate and the secondary low-voltage plate, a cross mutual capacitance 1 formed by the primary high-voltage plate and the secondary high-voltage plate, and a cross mutual capacitance 2 formed by the primary low-voltage plate and the secondary low-voltage plate;

[0008] The two ends of the equivalent self-capacitor 1 are connected in parallel with capacitor 1 and inductor L1. The capacitance of capacitor 1 is greater than that of the equivalent self-capacitor 1. After the equivalent self-capacitor 1 and capacitor 1 are connected in parallel, they resonate with the inductor L1. The energy provided by the power supply is input into the primary side of the equivalent six-capacitor model through the transmitting coil. The equivalent inductor L of the transmitting coil tx The parallel capacitor C1 at both ends and the equivalent inductance L tx In series with the equivalent mutual capacitance 1, the capacitance of capacitor C1 is greater than the capacitance of the equivalent mutual capacitance 1, and the equivalent inductance L tx After being connected in parallel with capacitor C1, it resonates with the equivalent mutual capacitance 1;

[0009] The two ends of the equivalent self-capacitor 2 are connected in parallel with capacitor 2 and inductor L2. The capacitance of capacitor 2 is greater than that of the equivalent self-capacitor 2. After the equivalent self-capacitor 2 and capacitor 2 are connected in parallel, they resonate with the inductor L2. The energy output by the secondary side of the equivalent six-capacitor model is recorded to the load through the receiving coil. The equivalent inductor L of the receiving coil rx The parallel capacitor C2 at both ends and the equivalent inductance L rx In series with the equivalent mutual capacitance 2, the capacitance of capacitor C2 is greater than the capacitance of the equivalent mutual capacitance 2, and the equivalent inductance L rx After being connected in parallel with capacitor C2, it resonates with the equivalent mutual capacitance 2.

[0010] The present invention wraps the high-voltage plate with a low-voltage plate. This, since the plate itself is a good conductor (copper), creates an electrostatic shielding effect, encapsulating the high-voltage radiation generated by the high-voltage plate and isolating it from the external environment, significantly reducing the radiation intensity. Furthermore, the present invention design eliminates the traditional equivalent induced current source (ICS) and equivalent induced voltage source (IVS) compensation circuits. Instead, it designs a new compensation circuit based on an equivalent six-capacitor model. This resonant compensation of the equivalent six-capacitor model leaves only relatively small cross-capacitances, significantly simplifying circuit analysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 is a plan view of a low-radiation electric field coupler in an embodiment;

[0012] Figure 2 is an equivalent circuit diagram of a compensation circuit of an embodiment;

[0013] Figures 3A to 3D It shows the V after PSIM simulation. a 、V c 、V d and output voltage;

[0014] Figure 4 The simulation results of the electric field radiation intensity are shown. DETAILED DESCRIPTION

[0015] Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiments are only used to illustrate the present invention and are not used in limiting the scope of the present invention.In addition, should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall equally within the scope limited by the appended claims of the application.

[0016] like Figure 1 As shown, the electric field coupler of a horizontal quadrupole plate structure disclosed in this embodiment includes a primary high voltage plate P a , primary low voltage plate P c , secondary high voltage plate P d And the secondary low voltage plate P b . The secondary low voltage plate P b After grounding, notice that the primary low voltage plate P c The voltage is very low, almost 0. Therefore, combined with Figure 2 The present invention uses the secondary low voltage plate P b Wrap around the primary high voltage plate P a , use the primary low voltage plate P c Wrap around the secondary high voltage plate P d .

[0017] In this embodiment, the size parameters of the obtained electric field coupler are as follows: Figure 1 and Figure 2 shown.

[0018] like Figure 2 As shown, the electric field coupler obtained in this embodiment is equivalent to an equivalent six-capacitor model. It should be noted that this is just a simple example of a physical structure. In fact, any structure in which two plates wrap around two other plates can be equivalent to the equivalent six-capacitor model.

[0019] The six equivalent capacitors in the equivalent six-capacitor model are: the primary high-voltage plate P a and the secondary low voltage plate P b The equivalent self-capacitance C ab , by the primary low voltage plate P c With the secondary high voltage plate P d The equivalent self-capacitance C formedcd , primary high voltage plate P a With the primary low voltage plate P c The equivalent mutual capacitance C formed ac , secondary high voltage plate P d and the secondary low voltage plate P b The equivalent mutual capacitance C formed bd , primary high voltage plate P a With the secondary high voltage plate P d The cross mutual capacitance C ad And the primary low voltage plate P c and the secondary low voltage plate P b The cross mutual capacitance C bc .

[0020] based on Figure 1 The size parameters shown (primary high voltage plate P a , secondary low voltage plate P b , primary low voltage plate P c And the secondary high voltage plate P d The width is 300mm), then C ab =53.5pF, C cd =53.1pF, C ac =44.4pF, C bd =44.4pF, C ad =0.33pF, C bc =16.2pF.

[0021] The equivalent circuit of the compensation circuit designed by the present invention is shown in FIG3. The present invention connects capacitors and inductors to make C ac 、C bd 、C ab 、C cd Reaching the resonance state. And because C bc with C ad The cross mutual capacitance between the plates is much smaller than the other four capacitances, so it can be ignored in the circuit analysis. In this way, the circuit can be regarded as the input voltage directly added to the load R L superior.

[0022] Figure 2 In, L tx is the equivalent inductance of the transmitting coil, L rx is the equivalent inductance of the receiving coil. In numerical design, since the inductor with large inductance is more expensive and larger in size, the present invention reduces the required inductance as much as possible. ac 、C bd 、C ab 、C cd Small, the present invention is respectively in C ab 、Ccd A large capacitance C is connected in parallel at both ends p ', which can reduce the required resonant inductance. In this embodiment, C ab with C p The capacitance after parallel connection is 500pF, C cd with C p 'The capacitance after parallel connection is also 500pF. Similarly, in L tx , L rx The large-capacitance capacitors C1 and C2 connected in parallel at both ends can also be used to reduce the required inductance value. In this embodiment, C1 = C2 = 355.6pF. In this embodiment, the inductor L1 = 12.66μH. p C after ′ ab Mutual resonance. L tx =15.83μH, L tx After connecting C1 in parallel with C ac Mutual resonance. Inductor L2 = 12.66μH, inductor L2 and parallel C p C after ′ cd Mutual resonance. L rx =15.83μH, L rx After connecting C2 in parallel with C bd Mutual resonance.

[0023] The electric field coupler was simulated using Maxwell, and after the compensation circuit was introduced, it was simulated using PSIM to obtain V a ( Figure 2 The voltage at node a), V c ( Figure 2 The voltage of node c), V d ( Figure 2 The voltage of the node d) and the output voltage are as follows Figures 3A to 3D Substitute the value obtained from PSIM back into Maxwell for low radiation verification and obtain Figure 4 The simulation data shown in Figure 2 are obtained by Figure 4 The simulation results shown in the figure show that this structural design can greatly reduce the external radiation of the plate, which illustrates the rationality of this physical structure and compensation circuit design method.

Claims

1. A method for designing a compensation circuit for an electric field coupler, wherein the electric field coupler comprises a primary high-voltage plate, a primary low-voltage plate, a secondary high-voltage plate, and a secondary low-voltage plate, wherein the secondary low-voltage plate is grounded, the voltage on the primary low-voltage plate is close to 0, the primary high-voltage plate is wrapped by the secondary low-voltage plate, and the secondary low-voltage plate forms an electrostatic shielding effect on the high-voltage radiation generated by the primary high-voltage plate; the secondary high-voltage plate is wrapped by the primary low-voltage plate, and the primary low-voltage plate forms an electrostatic shielding effect on the high-voltage radiation generated by the secondary high-voltage plate, wherein ... The compensation circuit design method comprises the following steps: The electric field coupler is equivalent to an equivalent six-capacitor model consisting of an equivalent self-capacitance 1 formed by the primary high-voltage plate and the secondary low-voltage plate, an equivalent self-capacitance 2 formed by the primary low-voltage plate and the secondary high-voltage plate, an equivalent mutual capacitance 1 formed by the primary high-voltage plate and the primary low-voltage plate, an equivalent mutual capacitance 2 formed by the secondary high-voltage plate and the secondary low-voltage plate, a cross mutual capacitance 1 formed by the primary high-voltage plate and the secondary high-voltage plate, and a cross mutual capacitance 2 formed by the primary low-voltage plate and the secondary low-voltage plate; The two ends of the equivalent self-capacitor 1 are connected in parallel with capacitor 1 and inductor L1. The capacitance of capacitor 1 is greater than that of the equivalent self-capacitor 1. After the equivalent self-capacitor 1 and capacitor 1 are connected in parallel, they resonate with the inductor L1. The energy provided by the power supply is input into the primary side of the equivalent six-capacitor model through the transmitting coil. The equivalent inductor L of the transmitting coil tx The parallel capacitor C1 at both ends and the equivalent inductance L tx In series with the equivalent mutual capacitance 1, the capacitance of capacitor C1 is greater than the capacitance of the equivalent mutual capacitance 1, and the equivalent inductance L tx After being connected in parallel with capacitor C1, it resonates with the equivalent mutual capacitance 1; The two ends of the equivalent self-capacitor 2 are connected in parallel with capacitor 2 and inductor L2. The capacitance of capacitor 2 is greater than that of the equivalent self-capacitor 2. After the equivalent self-capacitor 2 and capacitor 2 are connected in parallel, they resonate with the inductor L2. The energy output by the secondary side of the equivalent six-capacitor model is recorded to the load through the receiving coil. The equivalent inductor L of the receiving coil rx The parallel capacitor C2 at both ends and the equivalent inductance L rx In series with the equivalent mutual capacitance 2, the capacitance of capacitor C2 is greater than the capacitance of the equivalent mutual capacitance 2, and the equivalent inductance L rx After being connected in parallel with capacitor C2, it resonates with the equivalent mutual capacitance 2.

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