Offset-sensitive coupling mechanism and knife switch opening and closing position determination system

Abstract

The application discloses a kind of offset sensitive coupling mechanism and knife gate opening and closing in place determination system, coupling mechanism includes energy transmitting coil, energy transmitting coil magnetic core, energy receiving coil and energy receiving coil magnetic core, energy receiving coil moves along preset trajectory, vertically set up in the center position of energy transmitting coil opposite magnetic core, and opposite offset point is vertically set up on the preset trajectory close to energy transmitting coil, and opposite offset point vertically set up opposite offset magnetic core, when energy receiving coil and energy transmitting coil opposite, the upper end of opposite magnetic core opposite the central region of energy receiving coil, when energy receiving coil moves to offset point, the upper end of offset magnetic core opposite the central region of energy receiving coil.It is: the process that energy receiving coil occurs offset, coupling coefficient change rate is greater, it is helpful to system to better identify voltage variation, improve knife gate detection system reliability.

Description

Technical Field

[0001] The present invention relates to wireless power transmission technology and its application, and in particular to an offset-sensitive coupling mechanism and a switch opening / closing position determination system. Background Art

[0002] Wireless power transmission (WPT) enables the non-electrical contact transmission of electrical energy through media such as magnetic fields, electric fields, lasers, and microwaves. This technology effectively addresses the limited flexibility and safety risks associated with traditional wired power supply methods. Currently, experts and scholars both domestically and internationally have conducted research on this technology in applications such as electric vehicles, consumer electronics, and household appliances, and have achieved considerable theoretical results.

[0003] Inductively coupled wireless power transmission systems are usually equipped with an energy transmitting coil and an energy receiving coil. The energy transmitting end converts electrical energy into a high-frequency AC signal, which is then converted into magnetic field energy through the energy transmitting coil. After transmitting the signal over a certain distance, the energy is picked up by the energy receiving coil, thereby achieving wireless power transmission.

[0004] Among existing research results, most of the focus is on how to improve the efficiency of wireless power transmission and how to improve the anti-drift capability of electromagnetic coupling mechanisms so that their energy receiving coils can effectively receive wireless energy even in an offset state. For example, Chinese patents: 202110323214.2 disclose an anti-drift magnetic coupling mechanism and its design method, an electric vehicle wireless charging system, and 202110951828.5 disclose a wireless charging anti-drift coupling mechanism.

[0005] However, some application scenarios require an offset-sensitive coupling mechanism. For example, the Chinese patent application 202210224235.3 filed by this research team discloses a system for determining whether a secondary voltage knife switch is in position based on wireless power transmission. A passive receiving coil is installed on the primary side of the knife switch; a magnetic energy transmitting coil is installed on the secondary side of the knife switch, with its power source drawn from the knife switch mechanism box. The secondary magnetic energy transmitting coil and the primary passive receiving coil transmit electrical energy through a coupled magnetic field. Because the transferred electrical energy is related to the degree of offset between the coils, i.e., the coupling coefficient, the voltage sensed by the energy receiving coil is compared with a pre-set threshold voltage to determine whether the knife switch is in position.

[0006] However, system reliability is dependent on the accuracy of induced voltage detection. A greater rate of change in the induced voltage—that is, a greater change in the induced voltage at the same offset distance of the energy receiving coil—significantly enhances system reliability. Therefore, a magnetic coupling mechanism is needed that can produce a significant change in the coupling coefficient even with the same coil offset distance, thereby increasing the reliability of the switch-open / close position determination system. Summary of the Invention

[0007] In view of this, the primary purpose of the present invention is to provide an offset-sensitive coupling mechanism so that when an offset occurs, the coupling coefficient between the energy transmitting coil and the energy receiving coil changes at a faster rate, thereby more conveniently and accurately realizing offset detection based on the change of the induced voltage.

[0008] To achieve the above object, the technical solutions adopted by the present invention are as follows:

[0009] An offset-sensitive coupling mechanism includes an energy transmitting coil, an energy transmitting coil magnetic core, an energy receiving coil and an energy receiving coil magnetic core. The key feature of the coupling mechanism is that the energy receiving coil moves along a preset trajectory, a facing magnetic core is vertically arranged at the center of the energy transmitting coil, an offset point is preset near the energy transmitting coil on the preset trajectory, and an offset magnetic core is vertically arranged opposite the offset point. When the energy receiving coil is facing the energy transmitting coil, the upper end of the facing magnetic core faces the center area of ​​the energy receiving coil. When the energy receiving coil moves to the offset point, the upper end of the offset magnetic core faces the center area of ​​the energy receiving coil.

[0010] Optionally, the energy transmitting coil and the energy receiving coil are both solenoid coils.

[0011] Optionally, the energy transmitting coil and the energy receiving coil have the same shape and size, with a bottom radius of R1 and a height of h1.

[0012] Optionally, the energy transmitting coil magnetic core is a planar magnetic core with a thickness of h2, wherein the two ends of the energy transmitting coil magnetic core are semicircular with a radius of R2, and the centers of the semicircles at the two ends are respectively facing the facing magnetic conductive core and the offset magnetic conductive core, and the magnetic core material between the two ends is distributed along the preset trajectory, wherein R2 is greater than R1.

[0013] Optionally, the energy receiving coil magnetic core is a planar magnetic core and is circular with a radius of R2.

[0014] Optionally, the offset magnetic conductive core and the facing magnetic conductive core are both cylindrical magnetic cores, and have the same size, a height of h3, a bottom radius R3, and R3 is smaller than R1.

[0015] Optionally, the axis of the facing magnetic core coincides with the axis of the energy transmitting coil, the axis of the facing magnetic core is parallel to the axis of the offset magnetic core, and the distance between the two axes is 2R1.

[0016] Optionally, the preset trajectory is a planar arc trajectory.

[0017] Based on the above-mentioned coupling mechanism, another object of the present invention is to provide a knife switch opening and closing position determination system, the key of which is to adopt the offset-sensitive coupling mechanism mentioned above, the energy transmitting coil, the energy transmitting coil magnetic core, the facing magnetic core and the offset magnetic core are fixedly arranged at the low-voltage end of the knife switch, the energy receiving coil and the energy receiving coil magnetic core are arranged on the knife switch, and the energy receiving coil and the energy receiving coil magnetic core are driven to move along the preset trajectory during the opening and closing of the knife switch. When the knife switch is in the closed position, the energy receiving coil is located directly above the energy transmitting coil.

[0018] Optionally, a wireless energy transmitting circuit is connected to the energy transmitting coil, and a wireless energy receiving circuit is connected to the energy receiving coil, and whether the knife switch is in place is determined by detecting the voltage picked up by the energy receiving coil.

[0019] The remarkable effects of the present invention are:

[0020] (1) The magnetic coupling mechanism proposed in the present invention has a greater rate of change in the coupling coefficient during the process of the energy receiving coil being offset, which helps the system to better identify voltage changes and improve the reliability of the knife switch detection system.

[0021] (2) The magnetic coupling mechanism proposed in the present invention helps to improve the coupling coefficient between the energy transmitting coil and the energy receiving coil when they are facing each other, so that the voltage received by the secondary side is larger, which is beneficial for the system to detect and identify voltage changes. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 A schematic structural diagram of an offset-sensitive coupling mechanism in a specific embodiment of the present invention;

[0024] Figure 2 A diagram showing the movement path of the energy receiving coil in a specific embodiment of the present invention;

[0025] Figure 3 This is a flow chart of parameter design of an offset-sensitive coupling mechanism in a specific embodiment of the present invention;

[0026] Figure 4 A diagram showing the magnetic field distribution during the energy receiving coil deflection process in a specific embodiment of the present invention;

[0027] Figure 5 A comparison diagram of the coupling coefficients of the offset-sensitive coupling mechanism and the conventional magnetic coupling mechanism in a specific embodiment of the present invention;

[0028] Figure 6 This is a circuit diagram of a knife switch opening and closing position determination system in a specific embodiment of the present invention;

[0029] Figure 7 It is a schematic diagram of the installation structure of the knife switch opening and closing position determination system in a specific embodiment of the present invention. DETAILED DESCRIPTION

[0030] The following describes embodiments of the present invention in detail, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and are not to be construed as limiting the present invention.

[0031] In the description of the present invention, “plurality” means two or more, unless otherwise clearly defined.

[0032] like Figure 1 、 Figure 2 As shown, this embodiment provides an offset-sensitive coupling mechanism, including an energy transmitting coil, an energy transmitting coil magnetic core, an energy receiving coil, and an energy receiving coil magnetic core. The energy transmitting coil and the energy receiving coil are generally spiral tube coils, having the same shape and size, with a bottom radius of R1 and a height of h1. The energy transmitting coil magnetic core and the energy receiving coil magnetic core are both planar magnetic cores, with a thickness of h2. The energy transmitting coil magnetic core is located below the energy transmitting coil, and the energy receiving coil magnetic core is located above the energy receiving coil. The energy receiving coil generally moves along a preset trajectory. Taking the application scenario of a knife switch opening and closing position determination system as an example, the preset trajectory is a planar arc trajectory.

[0033] A facing magnetic core is vertically arranged at the center position of the energy transmitting coil, an offset point is preset near the energy transmitting coil on a preset trajectory, and an offset magnetic core is vertically arranged opposite the offset point. When the energy receiving coil is facing the energy transmitting coil, the upper end of the facing magnetic core faces the center area of ​​the energy receiving coil. When the energy receiving coil moves to the offset point, the upper end of the offset magnetic core faces the center area of ​​the energy receiving coil.

[0034] In a specific implementation, the two ends of the energy transmitting coil magnetic core are semicircular, with a radius of R2. The centers of the two semicircles are respectively opposite to the facing magnetic core and the offset magnetic core. The magnetic core material between the two ends is distributed along the preset track, and the overall shape is similar to a runway. The corresponding energy receiving coil magnetic core is also set to be circular with a radius of R2, where R2 is greater than R1, and usually R2 = 1.2R1.

[0035] In order to better improve the offset sensitivity, the offset magnetic core and the facing magnetic core are both cylindrical magnetic cores with the same size, height h3, bottom radius R3, and R3 is smaller than R1. Usually, R3 = 0.2R1 ~ 0.8R1, h3 = 0.8d, d is the distance between the energy transmitting coil and the energy receiving coil when facing each other. In specific implementation, the axis of the facing magnetic core coincides with the axis of the energy transmitting coil, and the axis of the facing magnetic core is parallel to the axis of the offset magnetic core, and the distance between the two axes is 2R1. The movable range of the energy receiving coil is set from the offset starting point to the offset ending point, and its path corresponds to the offset path with a length of l, then 2R1 is less than l.

[0036] The structural parameter selection process of the above coupling mechanism is as follows: Figure 3 As shown, first, the sizes of the energy transmitting coil and the energy receiving coil are designed, and based on the sizes of the energy transmitting coil and the energy receiving coil, the sizes of the facing magnetic core and the offset magnetic core and the positional relationship of the two magnetic cores are designed. Then, based on the positional relationship of the two magnetic cores and the sizes of the two coils, the size and position of the energy transmitting coil core are designed. Finally, the size of the energy receiving coil core is designed.

[0037] The simulation model is established in the finite element simulation software. When the energy receiving coil is offset, the magnetic field distribution is as follows Figure 4 As shown in the figure, when the offset distance is 0, since the two coils are directly connected to the magnetic material, the magnetic field will converge around the magnetic material. Since the magnetic permeability of the magnetic material is much greater than that of air, according to Newman's formula:

[0038]

[0039] As the magnetic permeability increases, the mutual inductance between the coils also increases. This magnetic coupling mechanism can increase the mutual inductance. In this case, the magnetic field in the facing core is directed downward, while the magnetic field in the offset core is directed upward. When the offset distance is R1, the energy receiving coil is located exactly between the facing core and the offset core. Due to the presence of the two magnetic cores, the magnetic field passing through the energy receiving coil is dispersed and canceled, resulting in a very small mutual inductance. When the offset distance is 2R1, the magnetic field in the energy receiving coil primarily passes through the offset core, while the magnetic field in the facing core is directed upward. At this point, the coupling coefficient between the coils becomes negative. Therefore, as the offset distance changes from 0 to 2R1, the coupling coefficient changes from a large positive value to a negative value, and the rate of change is very large, with the offset core playing a decisive role.

[0040] The change rate of the coupling coefficient of this magnetic coupling mechanism is similar to that of the magnetic coupling mechanism without offset magnetic core. Figure 5 As shown, it can be seen that compared with the magnetic coupling mechanism without offset magnetic core, the coupling coefficient change rate of the magnetic coupling mechanism of the invention is greater, and the change rate of the induced voltage of the energy receiving coil will also be greater. For the voltage detection device, when the same change in voltage is detected, the offset of the magnetic coupling mechanism of the invention will be smaller. When it is used in the knife switch detection system, the reliability will be greatly enhanced.

[0041] Therefore, this embodiment also provides a knife switch opening and closing position determination system, which adopts the offset-sensitive coupling mechanism described above, wherein the energy transmitting coil, the energy transmitting coil magnetic core, the facing magnetic core and the offset magnetic core are fixedly arranged at the low-voltage end of the knife switch, and the energy receiving coil and the energy receiving coil magnetic core are arranged on the knife switch. During the opening and closing process of the knife switch, the energy receiving coil and the energy receiving coil magnetic core are driven to move along the preset trajectory. When the knife switch is in the closed position, the energy receiving coil is located directly above the energy transmitting coil.

[0042] In specific implementation, a wireless energy transmitting circuit is connected to the energy transmitting coil, and a wireless energy receiving circuit is connected to the energy receiving coil. Whether the knife switch is in place is determined by detecting the voltage picked up by the energy receiving coil.

[0043] by Figure 6 、 Figure 7 As shown, Figure 6 and Figure 7 The circuit diagram and installation structure diagram of the knife switch opening and closing position discrimination system based on electromagnetic tracking are given. The system includes power supply, rectifier circuit, inverter circuit, LCC compensation circuit, energy transmitting coil L p , energy receiving coil L s, capacitor compensation circuit, rectifier circuit and voltage detection module. The voltage detection module determines whether the knife switch is closed based on the output voltage u.

[0044] The secondary circuit includes the secondary coil L s , secondary side compensation capacitor C s , rectifier circuit, DC / DC conversion link, load R L And detection accessories, the detection part includes A / D sampling module, single chip voltage identification module, wifi signal sending module. Among them, the secondary coil generates induced voltage by coupling with the primary coil; the secondary compensation capacitor C s With the secondary coil L s It forms an electric energy transmission channel; the rectifier circuit converts AC power into DC power; the DC / DC converter converts the rectified DC power into the DC voltage required for the accessories to work; the load R L And the detection accessories constitute the knife switch status collection and sending device.

[0045] Primary compensation capacitor C p 、C f , compensation inductance L f , primary coil L p , secondary coil L s , secondary side compensation capacitor C s satisfy:

[0046]

[0047] Wherein, f is the operating frequency of the high-frequency inverter.

[0048] Under the condition of satisfying formula (2), the secondary side reflection impedance Z M for:

[0049]

[0050] where R eq is the secondary side equivalent load, R s is the internal resistance of the pickup coil, and M is the mutual inductance between the transmitting coil and the pickup coil.

[0051] System total input impedance Z in for:

[0052]

[0053] where R f For the compensation coil L f Internal resistance, R s The secondary coil L s Internal resistance.

[0054] Assume that the rectified voltage u0 is:

[0055] u0=E (5)

[0056] Inverter output voltage u AB for:

[0057]

[0058] Inverter output current i f for:

[0059]

[0060] Primary current i p for:

[0061]

[0062] Secondary current i s for:

[0063]

[0064] Due to the effect of the invented magnetic coupling mechanism, the mutual inductance M between the coils increases, so the secondary current i s Increase.

[0065] Equivalent load voltage for:

[0066]

[0067] The actual load terminal voltage effective value U is:

[0068]

[0069] The knife switch opening and closing position determination system determines whether the knife switch is closed by judging the effective value of the load voltage. Therefore, the increase of the actual load end voltage effective value U will improve the detection accuracy of the voltage detection module.

[0070] In summary, it can be seen that the offset-sensitive coupling mechanism and the knife switch opening and closing position determination system proposed in the present invention are such that when the knife switch is opened, the energy receiving coil is offset accordingly, and the rate of change of the coupling coefficient between the energy receiving coil and the energy transmitting coil is greater, causing a greater change in the voltage received by the energy receiving coil, thereby improving the sensitivity of the knife switch opening and closing position determination system. Moreover, the present invention can increase the coupling coefficient when the two coils are facing each other, thereby increasing the transmission voltage and improving the reliability of the knife switch opening and closing position determination system.

[0071] Finally, it should be noted that what is disclosed above is only a preferred embodiment of the present invention, and of course it cannot be used to limit the scope of rights of the present invention. Ordinary technicians in this field can understand that all or part of the processes of the above embodiment are implemented, and equivalent changes made in accordance with the claims of the present invention are still within the scope of the invention.

Claims

1. An offset-sensitive coupling mechanism, comprising an energy transmitting coil, an energy transmitting coil magnetic core, an energy receiving coil and an energy receiving coil magnetic core, characterized in that: The energy receiving coil moves along a preset trajectory, and a facing magnetic core is vertically arranged at the center position of the energy transmitting coil. An offset point is preset on the preset trajectory close to the energy transmitting coil, and an offset magnetic core is vertically arranged opposite to the offset point. When the energy receiving coil is facing the energy transmitting coil, the upper end of the facing magnetic core faces the center area of ​​the energy receiving coil. When the energy receiving coil moves to the offset point, the upper end of the offset magnetic core faces the center area of ​​the energy receiving coil.

2. The offset-sensitive coupling mechanism according to claim 1, wherein: The energy transmitting coil and the energy receiving coil are both solenoid coils.

3. The offset-sensitive coupling mechanism according to claim 2, wherein: The energy transmitting coil and the energy receiving coil have the same shape and size, with a bottom radius of R1 and a height of h1.

4. The offset-sensitive coupling mechanism according to claim 3, wherein: The energy transmitting coil magnetic core is a planar magnetic core with a thickness of h2. The two ends of the energy transmitting coil magnetic core are semicircular with a radius of R2. The centers of the semicircles at the two ends are respectively opposite to the facing magnetic core and the offset magnetic core. The magnetic core material between the two ends is distributed along the preset trajectory, wherein R2 is greater than R1.

5. The offset-sensitive coupling mechanism according to claim 4, wherein: The energy receiving coil magnetic core is a planar magnetic core and is circular with a radius of R2.

6. The offset-sensitive coupling mechanism according to claim 3, 4 or 5, characterized in that: The offset magnetic conductive core and the facing magnetic conductive core are both cylindrical magnetic cores with the same size, a height of h3, a bottom radius R3, and R3 is smaller than R1.

7. The offset-sensitive coupling mechanism according to claim 6, wherein: The axis of the facing magnetic core coincides with the axis of the energy transmitting coil. The axis of the facing magnetic core is parallel to the axis of the offset magnetic core, and the distance between the two axes is 2R1.

8. The offset-sensitive coupling mechanism according to claim 6, wherein: The preset trajectory is a planar arc trajectory.

9. A knife switch opening and closing position determination system, characterized in that: The offset-sensitive coupling mechanism according to any one of claims 1 to 8 is adopted, wherein the energy transmitting coil, the energy transmitting coil magnetic core, the facing magnetic conductive core and the offset magnetic conductive core are fixedly arranged at the low-voltage end of the knife switch, and the energy receiving coil and the energy receiving coil magnetic core are arranged on the knife switch. During the opening and closing process of the knife switch, the energy receiving coil and the energy receiving coil magnetic core are driven to move along the preset trajectory. When the knife switch is in the closed position, the energy receiving coil is located directly above the energy transmitting coil.

10. The knife switch opening and closing position determination system according to claim 9 is characterized in that: The energy transmitting coil is connected to a wireless energy transmitting circuit, and the energy receiving coil is connected to a wireless energy receiving circuit. Whether the knife switch is in place is determined by detecting the voltage picked up by the energy receiving coil.

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