Hybrid EM-LC resonator

Abstract

A hybrid EM-LC resonator for wireless power transmission (WPT) systems comprises multiple capacitive loops and LC circuits, each having mutual inductance in a non-resonant operating mode. This resonator is usable in wireless energy transmission systems. The system comprises transmitter antenna components and receiver antenna components, each component comprising at least two separate circuits. One way to separate the circuits is to place them at a predetermined distance from each other, as shown in the diagram below. Sufficient separation of the circuits is necessary to allow for relatively loose coupling between them.

Description

Background Art

[0001] One of the present inventions is a hybrid EM-LC resonator for a wireless power transfer (WPT) system, which resonator includes a capacitive loop and the mutual inductance of an LC circuit in a non-resonant operation mode. This resonator can be used in a wireless energy transmission system. This system includes a transmitter antenna component and a receiver antenna component, and each component includes at least two mutually separated circuits. One way to separate the circuits is to arrange the circuits at a preselected distance from each other as shown in the following figure. In order to enable a relatively loose coupling between the circuits, it is necessary to sufficiently separate the circuits.

Summary of the Invention

[0002] Each of the circuits is an LC circuit having the same resonance frequency, and each circuit is powered from the same power frequency source through a parallel or series connection with a power frequency generator. The resonance frequency of the system is relatively low due to the electromagnetic interaction between the LC circuits, and these LC circuits share inductance and capacitance, thereby reducing the actual reactive impedance of the antenna.

Brief Description of the Drawings

[0003] [Figure 1] It is a schematic diagram showing an embodiment of the system of the present invention that produces a boosting effect by increasing the induced voltage without requiring a conventional step-up transformer. [Figure 2] It is a schematic diagram showing the structure of the hybrid EM-LC resonator of the present invention. [Figure 3] It is a schematic diagram showing how the present invention reduces the parasitic (i.e., unusable) EM field related to the AC charge of the loop wiring in a system having three branches forming an AC dipole. [Figure 4]This diagram illustrates how further reduction of undesirable parasitic multipole E-fields can be achieved by rotating the loops of the system, and shows a pair of schematic diagrams of embodiments of the present invention, which, in contrast to the dipole configuration of another embodiment shown to the left of the quadrupole configuration in Figure 4, rotates one of the two loops by 180 degrees to create a quadrupole configuration of the parasitic E-field in a two-loop structure consisting of one capacitance and one inductor. [Figure 5] This diagram shows how further reduction of undesirable parasitic multipole E-fields can be achieved by rotating the loops of the system, and, similar to Figure 4, it shows two embodiments of the present invention, a pair of schematic diagrams of embodiments of the present invention, comparing the hexapole configuration of Figure 3 with an embodiment in which one of the two loops is rotated by 60 degrees to change the hexapole configuration to a dodecapole configuration in a two-loop structure consisting of three capacitances and three inductors. [Figure 6] This is a schematic diagram of another embodiment showing that active field suppression can be achieved by adding further current damping loops to the system of the present invention. [Modes for carrying out the invention]

[0004] Version of the invention As shown in Figure 1In one version of the system, the operating frequency is 120 kHz, and the self-resonant frequency of each LC circuit is 200 kHz. Circuit 1 has inductance L1 and capacitance C1, and circuit 2 has inductance L2 and capacitance C2. Each LC circuit operates at a frequency substantially lower than its own resonant frequency, so that each LC circuit has capacitive impedance, i.e., each LC circuit itself becomes a capacitive loop during system operation. The system inductance is the mutual inductance of the LC circuits, meaning that the system inductance is related to the EM interaction of the wiring, not to the wiring itself. This system structure also substantially increases the density of the EM field generated by the system, to almost twice the density of conventional systems. The increase in density is due to loose coupling and anti-damping. Anti-damping occurs because these circuits generate in-phase EM fields, increasing the overall density of the EM field. In other words, the self-resonant frequency of a single circuit is much higher than the resulting operating frequency. This system achieves a voltage boost effect by increasing the induced voltage, without requiring a conventional step-up transformer.

[0005] This system is a hybrid EM-LC resonator rather than a simple LC resonator or EM resonator, because each LC circuit exhibits capacitive behavior, and the system's resonant frequency is much lower than the resonant frequency of each individual LC circuit. To achieve the functionality of this system, the LC circuits are positioned at a predetermined distance from each other to achieve relatively loose, non-resonant coupling at frequencies substantially lower than their self-resonant frequencies. The predetermined distance is 5% to 25% of the size of the LC circuits, and each LC circuit is preferably formed as a circle or loop. For example, a system with multiple transmitters, each formed as a circle or loop with a diameter of 3m, would be arranged in a coaxial configuration, with a distance of 30cm between the planes containing the loops, and the first loop positioned above the second loop, and so on, with as many transmitters as there are transmitters in the system. A typical frequency range associated with loose coupling is 1.3 to 1.8 times lower than the self-resonant frequency.

[0006] Conventional wireless energy transmission systems, unlike the invention of the system described in this application, utilize the resonant coupling of resonant LC circuits in which the transmitting LC resonator and the receiving LC resonator have the same resonant frequency. The hybrid EM-LC resonator of the present invention, unlike such conventional systems, has a resonant frequency associated with each LC circuit that is substantially higher than the operating frequency (the frequency associated with the system). The hybrid EM-LC resonator of the present invention can be used as a transmitter or receiver and comprises multiple LC circuits with no galvanic connections between the LC circuits. Each LC circuit has its own resonant frequency, and each LC circuit in the system has the same resonant frequency. The resonant frequency of each LC circuit is higher than the operating frequency. These LC circuits share impedance through EM interactions between the LC circuits, which results in a lower operating frequency, and in this case the operating frequency is lower than the resonant frequency of each LC circuit.

[0007] The system described in this application achieves its functionality by utilizing a capacitive load loop, which is a conductive wire, and by also utilizing the specific three-dimensional structure of the loop in conjunction with the capacitive behavior associated with the loop.

[0008] During operation, each LC circuit in the system has capacitive impedance. Unlike conventional systems that use inductive loops, the EM-LC resonator in this system has capacitive loops and mutual inductance between the LC circuits.

[0009] The hybrid EM-LC resonator described above can be used as a transmitter antenna and / or receiver antenna, and its advantages over conventional systems using resonant circuit coupling or inductive loops include:

[0010] 1. The density of the EM field generated by an EM-LC resonator is greater than the density of the EM field associated with a conventional LC resonator having the same voltage across the capacitance of the resonator. In one version of the system of the present invention, each comprising two LC circuits with a diameter of 3 meters and placed 30 cm apart from each other, an EM field with 1.8 times greater density was generated. In another version of the system of the present invention, comprising three LC circuits placed 20 cm apart from each other, an EM field with 2.6 times greater density was generated while maintaining the same voltage across the capacitance of each circuit. The system of the present invention provides a step-up effect with respect to the induced EM field without increasing the voltage or capacitance / inductance of each LC circuit.

[0011] 2. Because the magnetic fields generated by each wire are in opposite directions, the magnetic field density in the space between the wires of the LC circuit decreases. As a result, the total induced voltage associated with the LC circuit wiring decreases (for the same current) due to the actual decrease in the inductance of each wire, which is related to the decrease in magnetic field density near the wires, but at the same time, the EM field density related to the system operation remains unaffected. When the system operates, the current in the LC circuit generates an EM field of the same density, and at the same time, the voltage across the capacitance / inductance of the LC circuit required to generate such a current / EM field density decreases.

[0012] A hybrid EM-LC resonator that enhances the step-up effect and reduces EM noise. Due to the structure of the hybrid EM-LC resonator, a relatively high voltage needs to be applied to the capacitance of each LC loop. To further reduce the voltage applied to the reactance of the LC circuit, the capacitance and inductance of each loop are... Figure 2 As shown, the loop can be divided and distributed along the wiring. In an LC circuit, reactance refers to reactive resistance (including both capacitive and inductive resistance).

[0013] figure 2In this configuration, each capacitance must be modified so that the total capacitance remains constant. For example, if three equal capacitances are placed along the wiring of a loop, each capacitance must be three times the size of the initial (undivided) capacitance, as shown in the following equation, so that the total capacitance remains constant: C1 = 1 / (1 / C11 + 1 / C12 + 1 / C13). In another example, when a power-frequency generator is connected in parallel to an LC circuit, each capacitance must be inversely proportional to the voltage driving it. Capacitors typically need to be driven by AC power sources that are galvanically isolated from each other. However, in a version where equal capacitances are placed equidistant from each other along the wiring of a loop, it is possible to drive all capacitances in parallel from the same power source, i.e., without galvanic isolation. In this version, the loop can be constructed with small LC resonators of the same impedance / frequency connected in series. This makes it possible to drive all LC resonators in a single loop with the same voltage / current source thanks to the symmetry of the system, and also makes this version of the system easier to implement from an engineering standpoint.

[0014] The system described in this application also results in a reduction of parasitic (i.e., unusable) EM fields associated with the AC charges on the loop wiring. The focus of the system is the vortex E-field induced in the volume surrounding the system of loops. However, there are also unused parasitic E-fields generated by each loop. For example, if a loop has one capacitance and one wire, the AC surface charge of the loop will generate an electric dipole EM field at the main power frequency. If the loop is divided into three, Figure 3 This will result in the creation of the AC6 pole shown.

[0015] Figure 3Thus, the hexapole field decreases very rapidly with distance, and furthermore, for the same AC current amplitude in the loop, the voltage across each capacitance of the loop (if the capacitances are equal) decreases to one-third, thereby reducing the density of the parasitic EM field generated by the system to one-third. Further reduction of the undesirable parasitic multipole E field can be achieved by rotating the loops relative to each other by a certain angle. For example, rotating one of two loops consisting of one capacitance and one inductance (a two-loop structure) by 180 degrees creates a quadrupole configuration of the parasitic E field instead of a dipole configuration, as shown below, and rotating one of two loops consisting of three capacitances and three inductances (a two-loop structure) by 60 degrees changes the hexapole configuration to a dodecapole configuration, and so on.

[0016] Figures 4 and 5 The method can be applied to any desired number of branches in each loop, including various numbers of divisions for various loops and various capacitances at various distances along the loop. This method can also be applied to any desired number of loops to obtain higher-order multipole configurations, thereby substantially reducing the parasitic E-field over distance (related to the AC surface charge of the wiring).

[0017] Hybrid EM-LC resonators that reduce the density of the EM field for reasons of biosafety. Figures 4 and 5 in ShownThe method reduces the voltage across the reactance of the loop and also reduces the parasitic E-field associated with the AC surface charge of the wiring. However, the density of the main EM field (the swirling EM field in the region around the antenna) increases. Active field suppression is used to reduce the density of the EM field in the region where humans are present. To achieve active field suppression in the system described in this application, an additional current "damping" loop can be added to the system. Such a loop typically has a diameter of 1 / 2 to 1 / 3 that of the other loops and is installed coaxially with the antenna loop at a predetermined distance from the plane passing through the antenna loop, typically 1 to 2 times the diameter of the damping loop. The current in the damping loop flows in the opposite direction to the current flow in the main loop of the antenna. As a result, the current in the damping loop produces the same EM field at the same frequency but is 180 degrees phase-shifted compared to the current in the main loop. This means that the field produced by the damping loop and the field produced by the antenna loop cancel each other out or at least partially suppress each other.

[0018] By selecting the appropriate current level for the damping loops, as well as the appropriate geometry and arrangement of the damping loops, a substantial reduction in the resulting EM field can be achieved in areas where humans are present. For example, one version of this system comprises a 3-meter diameter transmitting antenna, divided into three equal parts using the technique described in the paragraph above, with two loops spaced 30 cm apart from each other. Two damping loops, each 1.5 meters in diameter, were located 1.5 meters below the plane containing the lower loop of the transmitting antenna, spaced 30 cm apart from each other. The distance between the plane containing the lower loop of the transmitting antenna and the mounting surface (ground surface) was 5 meters. In this version, the optimal current for the damping loops was 120% of the current for the transmitting antenna loops, which reduced the density of the EM field at a height of 1 meter above the ground surface to 1 / 10. A schematic diagram of this version is shown below. Figure 6 It is shown there.

[0019] The advantages of actively suppressing the EM field generated by the antenna of the system described in this application for reasons of biosafety include the following.

[0020] 1. The density of the suppressed EM field at ground level and in the vicinity of the antenna is low enough to be fully safe for humans.

[0021] 2. The relatively low density of the EM field at ground level also results in a reduction of parasitic energy losses in the ground itself (caused by a decrease in the current induced in the ground), thus improving the efficiency of wireless energy transmission / reception of the system.

[0022] 3. Since the density of the EM field above the antenna increases, the power level / distance / efficiency of wireless energy transmission of the system is improved. The EM field of the damping loop reduces the density of the EM field that results above the transmitting antenna (typically by 5% - 15%), and that EM field also reduces the density of the EM field at ground level (to one-fifth to one-tenth). Therefore, the current of the antenna increases substantially, whereby the density of the EM field above the antenna increases accordingly, while the EM field at ground level is maintained at a safe density.

[0023] For various diameters / locations (heights) of the antenna loop and the damping loop, it is possible to determine the appropriate current level of the damping loop that maximally reduces the density of the EM field and realizes biosafety such as creating a safe area for human presence.

[0024] The methods and systems described above may encompass several distinct inventions having independent merit. While each of these inventions is disclosed in a preferred form, the specific embodiments of the invention disclosed and illustrated herein should not be constrained, as numerous variations are possible. The subject matter of the invention includes all novel and non-obvious combinations and partial combinations of the various elements, features, functions, and / or properties disclosed herein. The appended claims, in particular, point to specific combinations and partial combinations that are considered novel and non-obvious. Inventions embodied in other combinations and partial combinations of features, functions, elements, and / or properties may be claimed in an application claiming priority based on this application or a related application. Such claims, whether they cover a different invention or the same invention, and whether they are broader, narrower, equal to or different from the original claims, are still considered to be included in the subject matter of the invention of this disclosure.

Claims

[Claim 1] Multiple capacitive loops, Each of the LC circuits has mutual inductance in a non-resonant operating mode. A hybrid EM-LC resonator for wireless power transmission (WPT) systems, equipped with the following features.

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