Wireless charging receiver

Abstract

The present invention discloses a wireless charging receiving end, including a main line, wherein the main line has a receiving coil, a resonant circuit and a load, and is characterized in that it also includes: a protective inductor, which is connected in series with the receiving coil, and the inductance of the protective inductor is variable; a power supply unit, which supplies power to the protective inductor; a switch unit, which is connected in series between the power supply unit and the protective inductor, and the switch unit has a sampling controller, which obtains the electrical parameters of the main line and controls the power supply unit and the protective inductor to be disconnected or connected according to the electrical parameters. In the wireless charging receiving end of the present application, the protective inductor is connected in series with the receiving coil, and the switch unit controls whether to supply power to the protective inductor to adjust the inductance of the protective inductor, so as to change the resonant parameters of the receiving end, destroy the resonant state of the receiving coil and the transmitting coil, thereby no longer receiving energy, and avoiding damage to the receiving end.

Description

Technical Field

[0001] The invention relates to a receiving end of wireless charging. Background Art

[0002] In the process of wireless charging, especially high-power wireless charging, once the receiving end is unloaded, it will bring great safety problems. For example, the wireless charging of electric vehicles is mainly composed of a transmitting controller, a transmitting coil, a receiving coil and a receiving controller. Its basic principle is that the transmitting end is composed of a transmitting coil and a capacitor to form a resonant circuit to send electromagnetic energy outward, and the receiving end is composed of a receiving coil and a capacitor to form a resonant circuit to receive electromagnetic energy. The circuit topology of its transmission and reception is mainly divided into series resonance and parallel resonance. In order to increase power and increase output current, the receiving end cannot be unloaded.

[0003] However, accidents are inevitable during the charging process. Whether the vehicle moves or the receiving end fails, it is possible that the receiving end will be unloaded. Since there is no physical circuit connection between the transmitter and the receiver of the wireless charging system, if no protective measures are taken, the energy received by the receiving end cannot be released, which will cause damage to the receiving end and components such as filter capacitors, thereby causing damage to the entire receiving end.

[0004] The protection against no-load conditions at the receiving end is usually achieved through bilateral communication and information exchange between the transmitting end and the receiving end, with the transmitting end sending instructions or the receiving end judging based on overcurrent and other signals to cut off the energy transmission. Due to the delay and reliability issues of bilateral communication, when no-load conditions occur at the receiving end, the receiving end is still very likely to be damaged, which is not an effective protection method. Summary of the invention

[0005] In order to solve the above problems, the present invention provides a wireless charging receiving end, which has a good no-load protection function.

[0006] The wireless charging receiving end of the present application includes a main circuit, which has a receiving coil, a resonant circuit and a load, and is characterized in that it also includes: a protection inductor, which is connected in series with the receiving coil, and the inductance of the protection inductor is variable; a power supply unit, which supplies power to the protection inductor; a switch unit, which is connected in series between the power supply unit and the protection inductor, and the switch unit has a sampling controller, which obtains the electrical parameters of the main circuit; and controls the power supply unit and the protection inductor to be disconnected or connected according to the electrical parameters.

[0007] Preferably, the electrical parameter is voltage; when the voltage of the main line is greater than a preset voltage, the controller disconnects the power supply unit and the protective inductor.

[0008] Preferably, the protection inductor is two groups of saturable inductors connected in reverse series.

[0009] Preferably, the protection inductor is a coupled inductor having a magnetic core, on which a first winding and a second winding are wound, the first winding is connected in series with the receiving coil, and the second winding is connected to the switch unit; and the mutual inductance of the first winding and the second winding is zero.

[0010] Preferably, the main line also has a rectifier filter; the sampling controller obtains the electrical parameters after passing through the rectifier filter.

[0011] Preferably, the load is an electrical device and / or a rechargeable battery.

[0012] Preferably, the sampling controller is a relay.

[0013] In the wireless charging receiving end of the present application, the protection inductor and the receiving coil are connected in series, and the switch unit controls whether to supply power to the protection inductor to adjust the inductance of the protection inductor, so as to change the resonance parameters of the receiving end, destroy the resonance state of the receiving coil and the transmitting coil, so that energy is no longer received, thereby avoiding damage to the receiving end. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of a wireless charging receiving end of the present invention.

[0015] Reference numerals:

[0016] Battery load 0; receiving coil 1; resonant circuit 2; protection inductor 3; switch unit 4; power supply unit 5; rectifier filter 6; saturable inductor 31. DETAILED DESCRIPTION

[0017] Embodiments of the present invention are described in detail below, 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 only used to explain the present invention, and cannot be interpreted as limiting the present invention.

[0018] The present invention discloses a wireless charging receiving end (hereinafter referred to as the receiving end), which generally refers to a power receiving end used in a wireless charging device, and realizes wireless energy transmission through resonance with a transmitting end. The receiving end has a main circuit, which refers to a circuit for converting received energy into electric energy for use or storage. The main circuit has a receiving coil 1 and a resonant circuit 2. The receiving coil 1 is used to cooperate with the transmitting coil of the transmitting end of the wireless charging to realize energy transmission through resonance.

[0019] The receiving end also includes a protection inductor 3, a switch unit 4 and a power supply unit 5. The protection inductor 3 is connected in series with the receiving coil 1, the power supply unit 5 supplies power to the protection inductor 3, and the switch unit 4 is connected in series between the power supply unit 5 and the protection inductor 3. The power supply unit 5 can supply power to the protection inductor 3 by disconnecting or connecting the switch unit 4 ( Figure 1 In the figure, the switch unit 4 is drawn with a dotted line to show the situation where the power supply unit 5 and the protection inductor 3 are connected). That is, the switch unit 4 controls the power supply unit 5 and the protection inductor 3 to be disconnected or connected. The basis for its control is determined by the electrical parameters of the main line. The switch unit 4 has a sampling controller, and the above-mentioned "disconnection or connection" is realized by the sampling controller. The sampling controller collects the electrical parameters of the main line, and performs "disconnection" or "connection" operations according to the changes in the electrical parameters. Preferably, the switch unit 4 can use a relay as a sampling controller, especially a voltage relay, to control the disconnection or connection according to the voltage. In this way, it is known that the electrical parameter of the main line is preferably voltage. The sampling controller of the switch unit 4 can be integrated in the switch unit 4, or it can be an independent structure, and there is a circuit connection or communication connection between the switch unit 4.

[0020] It should be noted that the use of voltage relays and the selection of voltage as a representative of electrical parameters are examples. This example is also an example that is relatively easy to implement in practical applications of the present application. For the sampling controller, as a component of the switch unit 4, it can appear in the form of a part module or in the form of a circuit, that is, the collection of electrical parameters is realized through the circuit, and the connection of the circuit is controlled by the switch.

[0021] Of course, there is also a load 0 on the main line, otherwise the main line is an unloaded line. Load 0 is an electrical device, or it can be a rechargeable battery. Of course, both can be set in the main line at the same time.

[0022] The following describes how the above structure implements the protection function in dangerous situations (such as no-load at the receiving end).

[0023] The inductance of the protection inductor 3 is variable, and the change of its inductance is mainly realized by whether there is power supply. The switch unit 4 changes the connection relationship between the protection inductor 3 and the power supply unit 5. For example, if the voltage in the main line exceeds the preset voltage, the switch unit 4 disconnects the line between the power supply unit 5 and the protection inductor 3.

[0024] Specifically, the protective inductor 3 can produce different degrees of saturation according to the magnitude of the current flowing through it, thereby changing the inductance of the inductor. When no current passes through, the magnetic core is not saturated and the inductance is maximum; when the injected current completely saturates the magnetic core, the inductance is minimum. In other words, the switch unit 4 is closed, and the power supply unit 5 supplies power to the protective inductor 3 to saturate it. It should be noted that the power supply of the power supply unit 5 here is sufficient to saturate the protective inductor 3. The switch unit 4 is turned on, and the power supply unit 5 stops supplying power to the protective inductor 3, and the protective inductor 3 is not saturated, and the inductance becomes larger. In this application, because the switch unit 4 has two states of disconnection and connection, the current flowing through the protective inductor 3 is simply divided into "with current" and "without current". It is mentioned above that "the protective inductor 3 can produce different degrees of saturation according to the magnitude of the current flowing through it", and "with current" and "without current" belong to different current magnitudes.

[0025] Preferably, the protection inductor 3 is two groups of saturable inductors 31 connected in reverse series. The saturable inductor 31 has a magnetic core. When the main line is in a dangerous situation such as no-load, the voltage of the main line will increase. At this time, the switch unit 4 cuts off the connection, the protection inductor 3 does not pass current, and the magnetic core is not saturated, which is equivalent to two coupled inductors connected in series, and the inductance is the largest. At this time, the large inductance is connected in series to the receiving coil 1, so that its resonance with the transmitting coil is destroyed, and the wireless function is stopped; while in normal charging activities, the switch unit 4 is closed, so that the power supply unit 5 supplies power to the protection inductor 3, injects current to make the magnetic core completely saturated, the inductance is minimized, and the receiving coil 1 resonates normally with the transmitting coil. When wireless charging is working, the induced voltages generated on the two saturated inductors 31 coupled inductors connected in reverse series are of the same magnitude but opposite polarity, and can offset each other. The main principle of wireless charging is that the AC power input by the AC power supply is converted into DC power through the rectification and filtering unit, and then converted into high-frequency AC power through the inverter unit, and then loaded into the transmitting coil to generate high-frequency oscillation, thereby generating an alternating magnetic field above the transmitting coil. After the receiving coil 1 senses the magnetic field, it generates induced AC power, which is converted into DC power and then transmitted to the battery load to charge the battery.

[0026] Before wireless charging starts, the switch unit 4 is closed, and the power supply unit 5 supplies direct current to the protection inductor 3, so that the inductor is in a saturated state. At this time, the transmitter and the receiver can be in a resonant state, and wireless charging can be guaranteed at any time. When wireless charging starts, the protection inductor 3 continues to be powered, the resonant characteristics of the receiver will not change, and the transmitter and the receiver begin to transfer energy through resonance. Before wireless charging starts here, it means preparing for wireless charging but not actually starting charging, or it can be understood as the preparation stage before charging. In the preparation stage, power is supplied to the protection inductor 3 so that the transmitter and the receiver can be in a resonant state. If there is no intention to charge wirelessly, power can be withheld from the protection inductor 3. At this time, the inductance of the protection inductor 3 is the largest, and the receiving coil 1 cannot resonate with the transmitting coil.

[0027] When an accident occurs, such as the receiving end being unloaded, the switch unit 4 can detect changes in the electrical parameters of the main line, such as the voltage increasing beyond the preset voltage, and disconnect the power supply unit 5 to the protection inductor 3, so that the magnetic core is not saturated and the inductance increases, thereby changing the resonance parameters of the receiving coil 1 connected in series with it, so that it can no longer resonate with the transmitting coil. Stopping the power supply to the protection inductor 3 is equivalent to connecting an inductance in series with the receiving coil 1, which changes the resonance parameters of the receiving end, and the transmitting and receiving ends are no longer in a resonant state. The receiving end cannot continue to receive the energy transmitted by the transmitting end, and the receiving end and the load can be protected from damage even if the transmitting end is not cut off in time.

[0028] The power supply unit 5 may be an independent power source, such as the vehicle's electrical level. The power supply unit 5 may also be a rechargeable battery at the receiving end of wireless charging.

[0029] Furthermore, the main circuit is provided with a rectifier filter 6; the sampling controller obtains the electrical parameters after passing through the rectifier filter 6, and adjusts whether the protection inductor 3 can be powered according to the electrical parameters. The rechargeable battery is also connected after the rectifier filter 6.

[0030] Regarding the protection inductor 3, its purpose is to achieve a change in inductance, so as to prevent the receiving coil 1 and the transmitting coil from resonating in special circumstances (such as the above-mentioned no-load state). In the above example, the protection inductor 3 can be two sets of saturable inductors 31 connected in reverse series. In addition, other structures can be used for the present application.

[0031] For example, the protection inductor 3 is a coupled inductor, and the coupled inductor has a magnetic core, and the number of the magnetic cores is at least one. Windings are wound on the magnetic core, which are a first winding and a second winding, respectively. The first winding is connected in series with the receiving coil 1, and the second winding is connected with the switch unit 4. The mutual inductance between the first winding and the second winding is zero.

[0032] From the above description, it can be known that the present application can be simply summarized as: by adjusting the inductance of the protection inductor 3, it affects whether the receiving coil 1 can (or effectively) resonate with the transmitting coil, thereby realizing the protection function. Then, the connection between the second winding and the switch unit 4 is to enable the second winding to affect the inductance of the first winding connected in series to the receiving coil 1 under the action of the switch unit 4. Here, the switch unit 4 can achieve the above-mentioned influence by controlling whether the current value is passed through the second winding, that is, by whether power is supplied.

[0033] Specifically, the second winding is not powered, that is, no power is passed through the second winding, the magnetic core is not saturated at this time, the first winding has a first self-inductance, and the first self-inductance is maximum at this time. The first self-inductance is equivalent to the inductance of the protection inductor 3, which is connected in series to the receiving coil 1, affecting the resonance of the receiving coil 1 and the transmitting coil.

[0034] When the current value is passed through the second winding, that is, the power supply unit 5 supplies power to it, so that the magnetic core is saturated, the first winding has a second self-inductance at this time, the second self-inductance is smaller than the first self-inductance, and the second self-inductance is preferably 0, that is, the power supply is sufficient to saturate the magnetic core. The second self-inductance can also be equivalent to the inductance of the protection inductor 3, and the second self-inductance can also be not 0, as long as it is within a range that does not affect the normal operation of the receiving coil 1.

[0035] The specific values ​​of the first self-inductance and the second self-inductance are not limited in this application, because they will vary according to different application scenarios and different equipment selections, but the principles they follow are the same, that is: when the work of the receiving coil 1 needs to be affected to play a protective role, the second winding is not powered, so that the magnetic core cannot be saturated. In this way, the first winding will produce a larger first self-inductance, and the first self-inductance is connected in series to the receiving coil 1 to destroy the original resonance. During normal charging, the second winding is passed with a current sufficient to saturate the magnetic core, so that the first winding has a smaller or 0 second self-inductance, and the receiving coil 1 works normally, that is, the power supply of the power supply unit 5 is sufficient to make the first winding have a smaller or 0 second self-inductance. The smaller second self-inductance refers to a value that does not affect the normal operation of the receiving coil 1. Of course, the saturation or unsaturation of the above-mentioned magnetic core is not necessarily a fixed state. It can be considered that the inductance equivalent to the first self-inductance and the second self-inductance can enable the protective inductor 3 to complete its working purpose. That is to say, the "saturation" mentioned above does not necessarily refer to saturation in its physical sense. If the goal can be achieved, it is considered to be "saturated".

[0036] The above describes in detail the structure, features and effects of the present invention based on the embodiments shown in the drawings. The above is only a preferred embodiment of the present invention, but the present invention is not limited to the scope of implementation shown in the drawings. Any changes made according to the concept of the present invention, or modifications to equivalent embodiments with equivalent changes, which still do not exceed the spirit covered by the description and drawings, should be within the protection scope of the present invention.

Claims

1. A wireless charging receiving end, comprising a main circuit, wherein the main circuit has a receiving coil (1), a resonant circuit (2) and a load (0), characterized in that: Also includes: A protective inductor (3) is connected in series with the receiving coil (1), and the inductance of the protective inductor (3) is variable; A power supply unit (5) for supplying power to the protection inductor (3); A switch unit (4) is connected in series between the power supply unit (5) and the protection inductor (3), and the switch unit (4) has a sampling controller, the sampling controller acquires electrical parameters of the main line, and controls the power supply unit (5) and the protection inductor (3) to be disconnected or connected according to the electrical parameters; The electrical parameter is voltage; When the voltage of the main line is greater than a preset voltage, the controller disconnects the power supply unit (5) and the protective inductor (3).

2. The wireless charging receiving end according to claim 1, characterized in that: The protective inductor (3) is two groups of saturable inductors (31) connected in reverse series.

3. The wireless charging receiving end according to claim 1, characterized in that: The protection inductor (3) is a coupled inductor having a magnetic core, on which a first winding and a second winding are wound, the first winding being connected in series with the receiving coil (1), and the second winding being connected to the switch unit (4); and the mutual inductance of the first winding and the second winding is zero.

4. The wireless charging receiving end according to claim 1, characterized in that: The main line also has a rectifier filter (6); The sampling controller obtains the electrical parameters after passing through the rectifier filter (6).

5. The wireless charging receiving end according to claim 1, characterized in that: The load (0) is an electrical device and / or a rechargeable battery.

6. The wireless charging receiving end according to claim 1, characterized in that: The sampling controller is a relay.

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