CN211075558U

CN211075558U - Metal foreign matter detection equipment and wireless charging system

Info

Publication number: CN211075558U
Application number: CN201921635909.9U
Authority: CN
Inventors: 邱贝贝; 高摇光; 胡超
Original assignee: Zhongxing New Energy Automobile Co ltd
Current assignee: Zhongxing New Energy Automobile Co ltd
Priority date: 2019-09-26
Filing date: 2019-09-26
Publication date: 2020-07-24
Anticipated expiration: 2029-09-26

Abstract

The utility model discloses a metallic foreign matter check out test set and wireless charging system. The metal foreign matter detection equipment comprises an alternating current excitation circuit, a first coil, a second coil and a voltage detection circuit, wherein the first coil comprises a plurality of first coil units, each first coil unit comprises an even number of coils with opposite winding directions, the alternating current excitation circuit is connected with the first coil, the first coil is arranged between the second coil and a primary side coil of the wireless charging system, the second coil is connected with the voltage detection circuit, the second coil is arranged between the first coil and a secondary side coil of the wireless charging system, and the voltage detection circuit is connected with a processor. The alternating current excitation circuit and the first coil are added on the basis of the prior art, so that the metal foreign matter detection is realized when the energy transmission is not performed in the original wireless charging system, the influence of a magnetic field generated by the first coil on the second coil when the energy transmission is performed in the original wireless charging system is avoided, and the detection accuracy is improved.

Description

Metal foreign matter detection equipment and wireless charging system

Technical Field

The utility model relates to an electric automobile field of charging especially relates to a metallic foreign matter check out test set and wireless charging system.

Background

At present, two modes of wired charging and wireless charging are mainly adopted for charging the electric automobile. Although the efficiency of wired charging is high, the charging process is inflexible, a charging cable needs to be repeatedly plugged and pulled, and potential safety hazards such as sliding abrasion, lead aging and contact electric sparks exist. The wireless charging adopts a transformer with completely separated primary and secondary sides and no electric connection, and realizes the transmission of electric energy between the primary and secondary sides through air by utilizing the mutual magnetic field coupling of the primary and secondary sides. Obviously, direct electrical connection between the electric automobile and the charging power supply is removed, wireless transmission of electric energy is achieved, the electric automobile can be charged frequently in the process of traveling, and manual operation links in the charging process are reduced.

A detection coil is usually added between a primary coil and a secondary coil in the existing wireless charging system, in the energy transmission process of the wireless charging system, according to the electromagnetic induction principle, induction voltage is generated in a metal foreign body detection coil, when metal foreign bodies exist, the induction voltage of the detection coil where the metal foreign bodies exist can be changed due to the eddy current effect of metal, and the existence of the metal foreign bodies can be judged by detecting the change of the voltage. However, when the wireless charging system does not transmit energy, there is no electromagnetic field between the transmitting coil and the receiving coil, and the detecting coil cannot generate induced voltage according to the principle of electric induction, and thus cannot realize the function of detecting the metallic foreign objects.

SUMMERY OF THE UTILITY MODEL

A primary object of the utility model is to provide a metallic foreign matter check out test set and wireless charging system aims at solving among the prior art and can't carry out the technical problem that the metallic foreign matter detected when wireless charging system does not carry out energy transmission.

In order to achieve the above object, the present invention provides a metal foreign object detecting apparatus, which includes an ac excitation circuit, a first coil, a second coil, and a voltage detecting circuit; the first coil comprises a plurality of first coil units, and each first coil unit comprises an even number of coils with opposite winding directions; wherein the content of the first and second substances,

the alternating current excitation circuit is connected with the first coil and used for receiving an alternating current control signal and switching on or off according to the alternating current control signal;

the first coil is arranged between the second coil and a primary coil of the wireless charging system, and is used for generating an alternating magnetic field when the alternating current excitation circuit is conducted;

the second coil is connected with the voltage detection circuit, the second coil is arranged between the first coil and a secondary coil of the wireless charging system, and the second coil is used for feeding back corresponding induction voltage to the voltage detection circuit according to whether metal foreign matters exist or not when the first coil generates an alternating magnetic field;

the voltage detection circuit is connected with the processor and used for detecting the induction voltage and judging whether metal foreign matters exist according to the induction voltage.

Preferably, the coils in each first coil unit are symmetrically arranged.

Preferably, the first coil is arranged in parallel with respect to the second coil.

Preferably, the alternating current excitation circuit comprises an alternating current unit, a capacitor and a switch unit; wherein the content of the first and second substances,

the alternating current unit is connected with the first coil through the switch unit;

the capacitor is arranged between the switch unit and the first coil; or, the capacitor is arranged between the switch unit and the alternating current unit.

Preferably, the switching unit includes a switch, and the switch is respectively connected to the ac unit and one end of the first coil.

Preferably, the switch unit includes two switches, and each switch is connected to both ends of the first coil.

Preferably, the second coil includes a plurality of second coil units, each of which includes an even number of coils having opposite winding.

Preferably, the second coil is arranged in parallel with respect to the primary coil and the secondary coil.

The utility model also provides a wireless charging system, wireless charging system includes as above metallic foreign matter check out test set.

Preferably, the wireless charging system further comprises a first rectifying circuit, an inverter circuit, a primary coil, a secondary coil, a second rectifying circuit, a battery and a processor; the first rectifying circuit receives commercial power, the first rectifying circuit is connected with the primary coil through the inverter circuit, the metal foreign matter detection device is arranged between the primary coil and the secondary coil, the metal foreign matter detection device is connected with the processor, and the secondary coil is connected with the battery through the second rectifying circuit.

The utility model relates to a metallic foreign matter check out test set is including exchanging excitation circuit, first coil, second coil and voltage detection circuit, wherein, first coil includes the first coil unit of a plurality of, each first coil unit includes that even number is around to opposite coil, it is connected with first coil to exchange excitation circuit, first coil sets up between the primary coil of second coil and wireless charging system, the second coil is connected with voltage detection circuit, the second coil sets up between the secondary coil of first coil and wireless charging system, voltage detection circuit is connected with the treater. Through increasing interchange excitation circuit and first coil on prior art basis, realized that original wireless charging system carries out metallic foreign object and detects when not carrying out energy transmission to avoided original wireless charging system to carry out the influence of the magnetic field that first coil produced when energy transmission to the second coil, increased the accuracy that detects.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.

Fig. 1 is a schematic structural diagram of an embodiment of the metal foreign object detection apparatus of the present invention;

fig. 2 is a schematic cross-sectional view of the first coil, the second coil and the primary coil in the wireless charging system of fig. 1;

fig. 3 is a schematic diagram of a composition structure of the first coil unit in fig. 1;

fig. 4 is a schematic structural diagram of an embodiment of a wireless charging system according to the present invention.

The reference numbers illustrate:

the objects, features and advantages of the present invention will be further described with reference to the accompanying drawings.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.

It should be noted that, if directional indications (such as upper, lower, left, right, front and rear … …) are involved in the embodiment of the present invention, the directional indications are only used to explain the relative position relationship between the components, the motion situation, etc. in a specific posture (as shown in the drawings), and if the specific posture is changed, the directional indications are changed accordingly.

In addition, if there is a description relating to "first", "second", etc. in the embodiments of the present invention, the description of "first", "second", etc. is for descriptive purposes only and is not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions in the embodiments may be combined with each other, but it must be based on the realization of those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should not be considered to exist, and is not within the protection scope of the present invention.

The utility model provides a metallic foreign matter check out test set.

Referring to fig. 1 and 4, in an embodiment, the metallic foreign object detection apparatus includes an ac excitation circuit 100, a first coil 200, a second coil 300, and a voltage detection circuit 400; the first coil 200 includes a plurality of first coil units (not shown), each of which includes an even number of coils with opposite windings; the alternating current excitation circuit 100 is connected to the first coil 200, and the alternating current excitation circuit 100 is configured to receive an alternating current control signal and turn on or off according to the alternating current control signal; the first coil 200 is disposed between the second coil 300 and the primary coil 500 of the wireless charging system, and the first coil 200 is configured to generate an alternating magnetic field when the ac excitation circuit 100 is turned on; the second coil 300 is connected to the voltage detection circuit 400, the second coil 300 is disposed between the first coil 200 and the secondary coil 600 of the wireless charging system, and the second coil 300 is used for feeding back a corresponding induced voltage to the voltage detection circuit 400 according to whether a metal foreign object exists when the first coil 200 generates an alternating magnetic field; the voltage detection circuit 400 is connected to the processor CPU, and is configured to detect the induced voltage and determine whether there is a metal foreign object according to the induced voltage.

It should be understood that the primary coil 500 refers to a transmitting coil in a wireless charging system, and is generally disposed on the ground, and the secondary coil 600 refers to a receiving coil in a wireless charging system, and is generally disposed in a device to be charged.

It should be noted that, in the conventional wireless charging system, generally, only one detection coil, i.e., the second coil 300, is added above the primary coil 500 for detecting the metal foreign object, and when wireless charging is performed, the second coil 300 induces voltage, and since an eddy current effect occurs when the metal foreign object exists, the induced voltage of the second coil 300 changes, and thus, whether the metal foreign object exists can be determined by detecting the change of the induced voltage. However, when the wireless charging is not performed, the second coil 300 cannot induce a voltage, and thus cannot detect whether there is a metallic foreign object. Referring to fig. 2, in the present embodiment, one or more coils are added above the primary coil 500 and below the second coil 300 to generate a new alternating magnetic field, so that the second coil 300 can generate an induced voltage in the new alternating magnetic field, and then the existence of the metal foreign object is determined by detecting a change in the induced voltage of the second coil 300.

In a specific implementation, it is considered that, during the energy transmission process of the wireless charging system, the newly added first coil 200 also generates an induced voltage, which may be very high, so that, on one hand, the design of the excitation circuit of the first coil 200 is difficult, and, on the other hand, the detection of the induced voltage of the second coil 300 is affected. Referring to fig. 3, the first coil 200 may be designed to be composed of first coil units, each of which includes an even number of coils that are wound in the forward and reverse directions. Thus, according to the electromagnetic induction principle, the induced voltages of the forward and backward coils are mutually cancelled under the same magnetic field strength. Since the magnetic field generated by the primary coil 500 of the wireless charging system is substantially symmetrical in the direction of the second coil 300, the first coil 200 may be further arranged in parallel with respect to the second coil 300, and the forward and reverse windings of the first coil 200 are symmetrically designed, so that the induced voltage in the first coil 200 is small or substantially zero.

Further, with continuing reference to fig. 1 and 4, the ac excitation circuit 100 includes an ac unit 110, a capacitor C, and a switch unit K; wherein the alternating current unit 110 is connected to the first coil 200 via the switching unit K; the capacitor C is disposed between the switching unit K and the first coil 200; or, the capacitor C is disposed between the switch unit K and the ac unit 110.

It should be noted that, in the design of the excitation circuit of the newly added first coil 200, the switching unit K is added to control the access of the first coil 200, and when the first coil 200 is required to generate an alternating magnetic field, the switching unit K is controlled to be closed; the switch unit K is controlled to be switched off in the power transmission process of the wireless charging system, the first coil 200 is not connected, and the influence of an alternating magnetic field generated by the first coil 200 at the moment is avoided.

Specifically, the switch unit K includes a switch, and the switch is respectively connected to the ac unit 110 and one end of the first coil 200. Of course, the switch unit K may further include two switches, and each switch is connected to two ends of the first coil 200, which is not limited in this embodiment.

It should be understood that, in this embodiment, the capacitor C may be disposed before the switch unit K or after the switch unit K, and as another embodiment, the capacitor C may also be disposed inside the ac unit 110 to form a resonant network with the first coil 200, so as to select a desired electrical signal and suppress or filter an undesired signal. The resonant frequency of the first coil 200, that is, the frequency of the ac excitation circuit 100, may be the same as or different from the operating frequency of the wireless charging system, and the present embodiment is not limited thereto.

Further, the second coil 300 includes a plurality of second coil units, and each of the second coil units includes an even number of coils with opposite winding. The winding of the coil in the second coil unit can refer to fig. 3.

Further, the second coil is arranged in parallel with respect to the primary coil and the secondary coil.

It should be noted that, when the wireless charging system charges the device to be charged, the magnetic field for detecting the metal foreign object may be a magnetic field generated when the primary coil 500 and the secondary coil 600 work normally, or a magnetic field emitted by the primary coil 500 or other externally generated magnetic fields when the wireless charging system performs self-detection. These magnetic fields may have different regional magnetic flux changes, and in order to cancel the magnetic fluxes as much as possible, it is necessary to cancel the magnetic fluxes of the two coils in each second coil unit to the maximum extent, so that the voltage across the second coil 300 is as low as possible, even 0, that is, the current passing through the second coil 300 is as low as possible, even 0, and by forward-rewinding the coils in the second coil unit, the magnetic fluxes can be effectively cancelled, thereby reducing the influence of the second coil 300 on the magnetic fields of the primary coil 500 and the secondary coil 600.

It should be understood that, since the metallic foreign object has characteristics of changing the direction of the magnetic force lines or the strength of the magnetic force lines, when there is the metallic foreign object in the wireless charging system, in a same-direction and uniform magnetic field, the voltage across the second coil 300 is not equal to 0, and accordingly, the current passing through the second coil 300 is not equal to 0. The larger the area of the metallic foreign object covered on the metallic foreign object detection apparatus is, the larger the difference in magnetic flux is, and the larger the induced voltage across the second coil 300 is. By arranging the second coil 300 in parallel with the primary coil 500 and the secondary coil 600, it is possible to more accurately detect whether there is a metallic foreign object.

The metallic foreign object detection device comprises an alternating current excitation circuit, a first coil, a second coil and a voltage detection circuit, wherein the first coil comprises a plurality of first coil units, each first coil unit comprises an even number of coils with opposite winding directions, the alternating current excitation circuit is connected with the first coil, the first coil is arranged between the second coil and a primary coil of a wireless charging system, the second coil is connected with the voltage detection circuit, the second coil is arranged between the first coil and a secondary coil of the wireless charging system, and the voltage detection circuit is connected with a processor. Through increasing interchange excitation circuit and first coil on prior art basis, realized that original wireless charging system carries out metallic foreign object and detects when not carrying out energy transmission to avoided original wireless charging system to carry out the influence of the magnetic field that first coil produced when energy transmission to the second coil, increased the accuracy that detects.

The utility model also provides a wireless charging system, wireless charging system includes as above-mentioned metallic foreign matter check out test set, the structure of the metallic foreign matter check out test set of wireless charging system can refer to above-mentioned embodiment, no longer describe here again; it can be understood that, since the wireless charging system of the present embodiment adopts the technical solution of the above-mentioned metal foreign object detection device, the wireless charging system has all the above-mentioned beneficial effects.

Referring to fig. 4, the wireless charging system further includes a first rectification circuit 700, an inverter circuit 800, a primary coil 500, a secondary coil 600, a second rectification circuit 900, a battery B, and a processor CPU; the first rectification circuit 700 receives commercial power, the first rectification circuit 700 is connected with the primary coil 500 through the inverter circuit 800, the metal foreign matter detection device is arranged between the primary coil 500 and the secondary coil 600, the metal foreign matter detection device is connected with the processor CPU, and the secondary coil 600 is connected with the battery B through the second rectification circuit 900.

The principle of the metal foreign matter detection according to the present embodiment will be described below with reference to fig. 4:

when the wireless charging system does not transmit power, the switch unit K is closed, the ac excitation circuit 100 starts to operate, an alternating current is generated in the first coil 200 to generate an alternating magnetic field, an induced voltage is generated in the second coil 300, the voltage detection circuit 400 detects whether the induced voltage changes in real time, if the induced voltage of the second coil 300 changes, it is determined that a metal foreign object exists, and a metal foreign object fault is reported to a processor CPU of the wireless charging system. If the induced voltage of the second coil 300 is not changed, the voltage detection circuit 400 continues to detect in real time until the wireless charging system is ready to be started.

When the wireless charging system transmits power, the switch unit K is turned off, alternating current is generated in the primary coil 500 of the wireless charging system to generate an alternating magnetic field, induced voltage is generated in the second coil 300, the voltage detection circuit 400 detects whether the induced voltage changes in real time, if the induced voltage of the second coil 300 changes, it is determined that a metal foreign object exists, and a fault of the metal foreign object is reported to a processor CPU of the wireless charging system. If the induced voltage of the second coil 300 is not changed, the real-time detection is continued until the charging is finished. And after the charging is finished, the switch unit K is closed, and the metal foreign matter detection work is continued.

The embodiment can realize the metal foreign matter detection when the wireless charging system does not carry out power transmission by only adding one alternating current exciting circuit and one first coil in the original foreign matter detection equipment on the basis of not influencing the work of the original foreign matter detection equipment, and the realization circuit is simple and has low cost.

The above is only the preferred embodiment of the present invention, and not the scope of the present invention, all the equivalent structures or equivalent flow changes made by the contents of the specification and the drawings or the direct or indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A metal foreign matter detection device is applied to a wireless charging system and is characterized by comprising an alternating current excitation circuit, a first coil, a second coil and a voltage detection circuit; the first coil comprises a plurality of first coil units, and each first coil unit comprises an even number of coils with opposite winding directions; wherein the content of the first and second substances,

2. The metallic foreign object detection apparatus of claim 1, wherein the coils in each of the first coil units are symmetrically arranged.

3. The metallic foreign object detection apparatus according to claim 2, wherein the first coil is disposed in parallel with respect to the second coil.

4. The metallic foreign object detection apparatus according to claim 3, wherein the alternating current excitation circuit includes an alternating current unit, a capacitor, and a switch unit; wherein the content of the first and second substances,

5. The metallic foreign object detection apparatus of claim 4, wherein the switch unit includes a switch connected to the ac unit and one end of the first coil, respectively.

6. The metallic foreign object detection apparatus of claim 4, wherein the switch unit includes two switches, each of which is connected to both ends of the first coil.

7. The metallic foreign object detection apparatus according to claim 5 or 6, wherein the second coil includes a plurality of second coil units, each of which includes an even number of coils having opposite windings.

8. The metallic foreign object detection apparatus of claim 7, wherein the second coil is disposed in parallel with respect to the primary coil and the secondary coil.

9. A wireless charging system comprising the metallic foreign object detection apparatus according to any one of claims 1 to 8.

10. The wireless charging system of claim 9, further comprising a first rectifying circuit, an inverter circuit, a primary coil, a secondary coil, a second rectifying circuit, a battery, and a processor; the first rectifying circuit receives commercial power, the first rectifying circuit is connected with the primary coil through the inverter circuit, the metal foreign matter detection device is arranged between the primary coil and the secondary coil, the metal foreign matter detection device is connected with the processor, and the secondary coil is connected with the battery through the second rectifying circuit.