CN110912278B

CN110912278B - Wireless charging receiving end, protection method and system

Info

Publication number: CN110912278B
Application number: CN201911046999.2A
Authority: CN
Inventors: 毛云鹤; 武志贤; 游洪程
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2019-10-30
Filing date: 2019-10-30
Publication date: 2023-10-20
Anticipated expiration: 2039-10-30
Also published as: CN110912278A

Abstract

The application discloses a receiving end of wireless charging, a protection method and a system thereof, comprising the following steps: the power converter comprises a receiving coil, a compensation network, a power converter, a normally closed relay and a controller; the compensation network is a compensation circuit with a current source characteristic, so that the receiving coil and the compensation network form an equivalent current source for the receiving coil of the constant current source, the compensation network and the transmitting end of the rectifier under the combined action of the transmitting end; when the receiving end is started, the controller controls the normally closed relay to be closed, controls a specified switching tube in the power converter to be closed so that a load is bypassed, controls the normally closed relay to be opened and controls the receiving end to start working; or when the receiving end is shut down, the specified switching tube in the power converter is controlled to be closed, and then the normally closed relay is controlled to be closed, so that the load is bypassed, and then the receiving end is controlled to enter a shut down state. The output end of the compensation network is connected with the normally closed relay in parallel, and when the auxiliary power supply is powered down, the normally closed relay can bypass a load to protect a receiving end device.

Description

Wireless charging receiving end, protection method and system

Technical Field

The present application relates to the field of wireless charging technologies, and in particular, to a receiving end, a protection method and a system for wireless charging.

Background

With the aggravation of energy shortage and environmental pollution problems in modern society, electric automobiles have received extensive attention from various communities as new energy automobiles. The electric automobile uses the vehicle-mounted power battery pack as an energy source to drive the vehicle to run.

The charging mode of the electric automobile comprises contact charging and wireless charging at present, and the wireless charging mode is convenient to use, has no spark and electric shock hazard, so that the charging mode becomes the development direction of the electric automobile in the future.

The operation of the wireless charging system will be described with reference to fig. 1.

Referring to fig. 1, a schematic diagram of a wireless charging system is shown.

The wireless charging system comprises a wireless charging transmitting end (hereinafter referred to as transmitting end) and a wireless charging receiving end (hereinafter referred to as receiving end). Typically, the transmitting end is located on the ground and the receiving end is located on the vehicle.

Wherein, the transmitting terminal includes: inverter H1, transmitting-side compensation network 100, and transmitting coil Lp.

The inverter H1 generally includes four controllable switching transistors, Q1-Q4, respectively, and the inverter H1 inverts dc power output from the dc power supply into ac power.

The transmitting-end compensation network 100 compensates the ac power output from the inverter H1 and then transmits the compensated ac power to the transmitting coil Lp.

The transmitting coil Lp transmits the alternating current output from the inverter H1 in the form of an alternating magnetic field.

The receiving end comprises: a receiving coil Ls, a receiving-side compensation network 200 and a rectifier H2.

The receiving coil Ls receives electromagnetic energy emitted from the transmitting coil Lp in the form of an alternating magnetic field.

The receiving-end compensation network 200 compensates the alternating current output by the receiving coil Ls and then transmits the alternating current to the rectifier H2.

The rectifier H2 may include four controllable switching tubes S1-S4, respectively. The rectifier H2 rectifies the alternating current output from the receiving coil Ls into direct current to charge the load. For electric vehicles, the load is a vehicle-mounted power battery pack.

The transmitting end controller 101 controls the controllable switching tube of the inverter H1, the receiving end controller 201 controls the controllable switching tube of the rectifier H2, the communication module 300 of the receiving end performs wireless communication with the communication module 400 of the transmitting end, and the switching speed of the wireless communication is slower than that of the controllable switching tubes of the transmitting end and the receiving end. Once the control timing of the controllable switching tube in the rectifier H2 of the receiving end is problematic, the receiving end is directly damaged or the load is damaged.

Content of the application

In order to solve the technical problems in the prior art, the application provides a receiving end, a protection method and a system for wireless charging, which can ensure the safety of the receiving end and a load in the processes of switching on and switching off the receiving end and charging.

In a first aspect, an embodiment of the present application provides a receiving end for wireless charging, including: the power converter comprises a receiving coil, a compensation network, a power converter, a normally closed relay and a controller; the receiving coil converts the alternating magnetic field emitted by the emitting end into alternating current and transmits the alternating current to the compensation network; the compensation network compensates the alternating current and then transmits the alternating current to the rectifier; the normally closed relay is connected in parallel with the output end of the compensation network; the power converter rectifies the compensated alternating current into direct current and provides the direct current to a load; the compensation network is a compensation circuit with a current source characteristic, so that the receiving coil and the compensation network make the input end of the rectifier be a constant current source under the combined action of the transmitting end; when the receiving end is started, the controller controls the normally closed relay to be closed, and controls the switching tube in the power converter to be closed so that the load is bypassed, and then controls the normally closed relay to be opened and controls the receiving end to start working; or when the receiving end is shut down, the switching tube in the power converter is controlled to be closed, and then the normally closed relay is controlled to be closed, so that the load is bypassed, and then the receiving end is controlled to enter a shut down state.

Because the normally closed relay is closed in the corresponding state when no electricity exists, when the auxiliary power supply of the receiving end is powered off or fails, the load can be bypassed due to the existence of the normally closed relay so as to protect the devices of the receiving end. The auxiliary power supply is used for supplying power to the controller of the receiving end, and when the auxiliary power supply is not powered, the controller of the receiving end cannot work. When the auxiliary power supply of the receiving end is powered, the power can be supplied to the controller of the receiving end, and the controller of the receiving end can bypass the load by controlling the switching tube in the power converter. The scheme can bypass the load when the auxiliary power supply of the receiving end is powered on or powered off, so that the receiving end and the load are protected.

In a first possible implementation manner of the first aspect, when the receiving end is turned on, the controller is specifically configured to control the normally closed relay to be closed when the receiving end is turned on, and control the first part of the switching tubes in the power converter to be closed so that the load is bypassed; when the receiving end is shut down, the second part of switching tubes in the power converter are controlled to be closed, and then the normally closed relay is controlled to be closed, so that the load is bypassed; the first part of switching tubes are switching tubes of an upper half bridge arm of a rectifier in the power converter, switching tubes of a lower half bridge arm of the rectifier, or controllable switching tubes in a direct current conversion circuit in the power converter; the second part of switching tubes are switching tubes of an upper half bridge arm of a rectifier in the power converter, switching tubes of a lower half bridge arm of the rectifier, or controllable switching tubes in a direct current conversion circuit in the power converter; when the power converter comprises a direct current conversion circuit, the direct current conversion circuit is connected to the output end of the rectifier.

The switching tubes controlled during startup and shutdown can be the same or different, and the application is not particularly limited. However, when the rectifier in the power converter comprises a diode, which also comprises a switching tube, the diode needs to be located in the upper half-bridge and the switching tube in the lower half-bridge.

With reference to the first aspect and any one of the foregoing possible implementation manners, in a second possible implementation manner, the method further includes: a first field effect transistor and a second field effect transistor; the first field effect tube and the second field effect tube are connected in parallel at two ends of the normally-closed relay after being connected in reverse series; the controller is used for controlling the normally-closed relay to be disconnected when the receiving end is started, and then controlling the first field effect transistor and the second field effect transistor to be disconnected; when the receiving end is shut down, the first field effect transistor and the second field effect transistor are controlled to be closed, and then the normally-closed relay is controlled to be closed.

The purpose of the field effect transistor is to increase the on-resistance of the relay is small, but the speed of closing and opening the relay is slow due to the electromagnetic characteristics of the relay. The field effect transistor has the characteristics of high on and off speed, but has larger conduction loss. Therefore, the embodiment not only comprises the relay, but also comprises the field effect transistor, and the relay and the field effect transistor are connected in parallel to integrate the advantages of the two devices, so that the action speed of the switch can be improved, and the low conduction loss during conduction can be ensured.

With reference to the first aspect and any one of the foregoing possible implementation manners, in a third possible implementation manner, the method further includes: a bidirectional controllable switch; the two-way controllable switch is connected in parallel with two ends of the normally closed relay; the controller is used for controlling the normally closed relay to be disconnected when the receiving end is started, and then controlling the bidirectional controllable switch to be disconnected; when the receiving end is shut down, the bidirectional controllable switch is controlled to be closed, and then the normally closed relay is controlled to be closed.

The purpose of this embodiment is to add a bi-directional controllable switch because the on-resistance of the relay is small, but because the relay has electromagnetic properties, the speed of closing and opening the relay is slow. The bidirectional controllable switch is characterized by high on and off speed, but has larger conduction loss. Therefore, the embodiment not only comprises the relay, but also comprises the bidirectional controllable switch, the relay and the bidirectional controllable switch are connected in parallel, so that the advantages of the two devices can be combined, the action speed of the switch can be improved, and the low conduction loss during conduction can be ensured.

With reference to the first aspect and any one of the possible implementation manners of the first aspect, in a fourth possible implementation manner, the rectifier includes two bridge arms, and switching tubes of an upper half bridge arm and a lower half bridge arm of the two bridge arms are controllable switching tubes; when the receiving end is started, the controller controls the normally closed relay to be closed, and controls the switching tubes of the upper half bridge arm of the rectifier to be closed or the switching tubes of the lower half bridge arm to be closed so that the load is bypassed; when the current of the transmitting coil of the transmitting end is determined to be larger than a first preset current, the phase shift angle between the two bridge arms is controlled to gradually increase to a preset value, the switching tube of the upper half bridge arm and the switching tube of the lower half bridge arm are controlled to be conducted in a complementary mode, and then the receiving end is controlled to start to work.

With reference to the first aspect and any one of the foregoing possible implementation manners, in a fifth possible implementation manner, when the receiving end is turned off, it is determined that the current of the transmitting coil of the transmitting end is smaller than the second preset current and greater than the first preset current, the controller controls the phase shift angle between the two bridge arms to gradually decrease until the switching tubes of the upper half bridge arm of the rectifier are closed or the switching tubes of the lower half bridge arm of the rectifier are closed, and then controls the normally closed relay to be closed, so that the load is bypassed, and then controls the receiving end to enter the off state.

With reference to the first aspect and any one of the foregoing possible implementation manners, in a sixth possible implementation manner, the rectifier includes two bridge arms, switching tubes of an upper half bridge arm of the two bridge arms are diodes, and switching tubes of a lower half bridge arm of the two bridge arms are controllable switching tubes; when the receiving end is started, the controller controls the normally closed relay to be closed, controls the controllable switching tubes to be closed so that the load is bypassed, and controls the duty ratio of driving signals of the controllable switching tubes of the two bridge arms to be gradually reduced to a preset value when the current of the transmitting coil of the transmitting end is determined to be larger than a first preset current, and then controls the receiving end to start working.

With reference to the first aspect and any one of the foregoing possible implementation manners, in a seventh possible implementation manner, when the receiving end is turned off, it is determined that the current of the transmitting coil of the transmitting end is smaller than the second preset current and larger than the first preset current, the controller controls the duty ratios of the controllable switching tubes of the two bridge arms to gradually increase until the controllable switching tubes are all closed, then controls the normally closed relay to be closed, so that the load is bypassed, and then controls the receiving end to enter the off state.

With reference to the first aspect and any one of the possible implementation manners of the first aspect, in an eighth possible implementation manner, the rectifier includes a bridge arm, and switching tubes of an upper half bridge arm and a lower half bridge arm of the bridge arm are controllable switching tubes; when the receiving end is started, the controller controls the normally closed relay to be closed, controls the switching tube of the lower half bridge arm of the rectifier to be closed so that the load is bypassed, and controls the switching tube of the upper half bridge arm and the switching tube of the lower half bridge arm to be complementarily conducted when the current of the transmitting coil of the transmitting end is determined to be larger than a first preset current.

With reference to the first aspect and any one of the foregoing possible implementation manners, in a ninth possible implementation manner, when the receiving end is turned off, it is determined that the current of the transmitting coil of the transmitting end is smaller than the second preset current and larger than the first preset current, the controller controls the switching tube of the lower half bridge arm of the rectifier to be closed, and then controls the normally closed relay to be closed, so that the load is bypassed, and then controls the receiving end to enter the off state.

With reference to the first aspect and any one of the possible implementation manners of the first aspect, in a tenth possible implementation manner, the rectifier includes a bridge arm, a lower half bridge arm of the bridge arm is a controllable switch tube, and an upper half bridge arm of the bridge arm is a diode; when the receiving end is started, the controller controls the normally closed relay to be closed, controls the controllable switching tube of the rectifier to be closed so that the load is bypassed, and controls the switching state of the controllable switching tube with a preset duty ratio when the current of the transmitting coil of the transmitting end is determined to be larger than a first preset current.

With reference to the first aspect and any one of the foregoing possible implementation manners, in an eleventh possible implementation manner, when the receiving end is turned off, it is determined that the current of the transmitting coil of the transmitting end is smaller than the second preset current and larger than the first preset current, the controller controls the controllable switching tube to be closed, then controls the normally closed relay to be closed, so that the load is bypassed, and then controls the receiving end to enter the off state.

With reference to the first aspect and any one of the foregoing possible implementation manners, in a twelfth possible implementation manner, when the power converter includes a rectifier and a dc conversion circuit, the rectifier includes only a diode, and the dc conversion circuit includes a controllable switch tube.

In a second aspect, the embodiment of the application further provides a wireless charging protection method, which is applied to a wireless charging receiving end; the receiving end comprises: the power converter comprises a receiving coil, a compensation network, a power converter and a normally closed relay; the compensation network is a compensation circuit with a current source characteristic, so that the receiving coil and the compensation network make the input end of the rectifier be a constant current source under the combined action of the transmitting end; the method comprises the following steps: when the receiving end is started, the normally closed relay is controlled to be closed, a load is bypassed by controlling a switching tube in the power converter to be closed, and then the normally closed relay is controlled to be opened and the starting work of the receiving end is controlled; or when the receiving end is shut down, the switching tube in the power converter is controlled to be closed, and then the normally closed relay is controlled to be closed, so that the load is bypassed, and then the receiving end is controlled to enter a shut down state.

In a first implementation manner of the second aspect, when the receiving end is turned on, the normally closed relay is controlled to be closed, and a specified switching tube in the power converter is controlled to be closed so that the load is bypassed, and specifically includes: when the receiving end is started, the normally closed relay is controlled to be closed, and the load is bypassed by controlling the first part of switching tubes in the power converter to be closed; when the receiving end is shut down, the specified switching tube in the power converter is controlled to be closed, and then the normally closed relay is controlled to be closed, so that the load is bypassed, and the method specifically comprises the following steps: when the receiving end is shut down, the second part of switching tubes in the power converter are controlled to be closed, and then the normally closed relay is controlled to be closed, so that the load is bypassed; the first part of switching tubes are switching tubes of an upper half bridge arm of a rectifier in the power converter, switching tubes of a lower half bridge arm of the rectifier, or controllable switching tubes in a direct current conversion circuit in the power converter; the second part of switching tubes are switching tubes of an upper half bridge arm of a rectifier in the power converter, switching tubes of a lower half bridge arm of the rectifier, or controllable switching tubes in a direct current conversion circuit in the power converter; when the power converter comprises a direct current conversion circuit, the direct current conversion circuit is connected to the output end of the rectifier.

With reference to the second aspect and any one of the foregoing possible implementation manners, in a first possible implementation manner, the receiving end further includes: a first field effect transistor and a second field effect transistor; the first field effect tube and the second field effect tube are connected in parallel at two ends of the normally-closed relay after being connected in reverse series; when the receiving end is started, the method further comprises the following steps: before the first field effect transistor and the second field effect transistor are disconnected, the normally-closed relay is controlled to be disconnected; when the receiving end is powered off, the method further comprises the following steps: and before the normally-closed relay is controlled to be closed, the first field effect transistor and the second field effect transistor are controlled to be closed.

With reference to the second aspect and any one of the foregoing possible implementation manners, in a second possible implementation manner, the receiving end further includes: the two-way controllable switch is connected in parallel with two ends of the normally closed relay; when the receiving end is started up, the method further comprises the following steps: before controlling the bidirectional controllable switch, firstly controlling the normally closed relay to be disconnected; when the receiving end is powered off, the method further comprises the following steps: and before the normally-closed relay is controlled to be closed, the bidirectional controllable switch is controlled to be closed.

With reference to the second aspect and any one of the possible implementation manners of the second aspect, in a third possible implementation manner, the power converter includes a rectifier, the rectifier includes two bridge arms, and switching tubes of an upper half bridge arm and a lower half bridge arm of the two bridge arms are controllable switching tubes; when the receiving end is started, the normally closed relay is controlled to be closed, the switching tube in the power converter is controlled to be closed so that the load is bypassed, and then the normally closed relay is controlled to be opened and the starting work of the receiving end is controlled, and the method specifically comprises the following steps: when the receiving end is started, the normally closed relay is controlled to be closed, and the switching tubes of the upper half bridge arm of the rectifier are controlled to be closed or the switching tubes of the lower half bridge arm of the rectifier are controlled to be closed so that the load is bypassed; when the current of the transmitting coil of the transmitting end is determined to be larger than a first preset current, the phase shift angle between the two bridge arms is controlled to gradually increase to a preset value, the switching tube of the upper half bridge arm and the switching tube of the lower half bridge arm are controlled to be conducted in a complementary mode, and then the receiving end is controlled to start to work.

With reference to the second aspect and any one of the foregoing possible implementation manners, in a fourth possible implementation manner, when the receiving end is turned off, controlling a switching tube in the power converter to be closed, then controlling the normally closed relay to be closed, so that the load is bypassed, and then controlling the receiving end to enter a shutdown state, specifically including: when the receiving end is powered off, when the current of the transmitting coil of the transmitting end is determined to be smaller than the second preset current and larger than the first preset current, the phase shift angle between the two bridge arms is controlled to be gradually reduced until the switching tubes of the upper half bridge arm or the switching tubes of the lower half bridge arm of the rectifier are closed, then the normally closed relay is controlled to be closed, so that the load is bypassed, and then the receiving end is controlled to enter a power-off state.

With reference to the second aspect and any one of the possible implementation manners of the second aspect, in a fifth possible implementation manner, the power converter includes a rectifier, where the rectifier includes two bridge arms, switching tubes of an upper half bridge arm of the two bridge arms are diodes, and switching tubes of a lower half bridge arm of the two bridge arms are controllable switching tubes; when the receiving end is started, the normally closed relay is controlled to be closed, the switching tube in the power converter is controlled to be closed so that the load is bypassed, and then the normally closed relay is controlled to be opened and the starting work of the receiving end is controlled, and the method specifically comprises the following steps: when the receiving end is started, the normally closed relay is controlled to be closed, and the controllable switch tube is controlled to be closed so that the load is bypassed; when the current of the transmitting coil of the transmitting end is determined to be larger than a first preset current, the duty ratio of the driving signals of the controllable switching tubes of the two bridge arms is controlled to be gradually reduced to a preset value, and then the receiving end is controlled to start working.

With reference to the second aspect and any one of the foregoing possible implementation manners, in a sixth possible implementation manner, when the receiving end is turned off, controlling a switching tube in the power converter to be closed, then controlling the normally closed relay to be closed, so that the load is bypassed, and then controlling the receiving end to enter a shutdown state, specifically includes: when the receiving end is powered off, when the current of the transmitting coil of the transmitting end is determined to be smaller than the second preset current and larger than the first preset current, the duty ratio of the controllable switching tubes of the two bridge arms is controlled to be gradually increased until the controllable switching tubes are all closed, then the normally closed relay is controlled to be closed, so that the load is bypassed, and then the receiving end is controlled to enter a power-off state.

With reference to the second aspect and any one of the possible implementation manners of the second aspect, in a seventh possible implementation manner, the power converter includes a rectifier, where the rectifier includes a bridge arm, and switching tubes of an upper half bridge arm and a lower half bridge arm of the bridge arm are controllable switching tubes; when the receiving end is started, the normally closed relay is controlled to be closed, the switching tube in the power converter is controlled to be closed so that the load is bypassed, and then the normally closed relay is controlled to be opened and the starting work of the receiving end is controlled, and the method specifically comprises the following steps: when the receiving end is started, the normally closed relay is controlled to be closed, and the switching tube of the lower half bridge arm of the rectifier is controlled to be closed so that the load is bypassed; when the current of the transmitting coil of the transmitting end is determined to be larger than a first preset current, the switching tube of the upper half bridge arm and the switching tube of the lower half bridge arm are controlled to be conducted in a complementary mode.

With reference to the second aspect and any one of the foregoing possible implementation manners, in an eighth possible implementation manner, when the receiving end is turned off, controlling a switching tube in the power converter to be closed, then controlling the normally closed relay to be closed, so that the load is bypassed, and then controlling the receiving end to enter a shutdown state, specifically including: when the receiving end is shut down, when the current of the transmitting coil of the transmitting end is determined to be smaller than the second preset current and larger than the first preset current, the switching tube of the lower half bridge arm of the rectifier is controlled to be closed, the normally closed relay is controlled to be closed, so that the load is bypassed, and the receiving end is controlled to enter a shut down state.

With reference to the second aspect and any one of the possible implementation manners of the second aspect, in a ninth possible implementation manner, the power converter includes a rectifier, where the rectifier includes a bridge arm, a lower half bridge arm of the bridge arm is a controllable switch tube, and an upper half bridge arm of the bridge arm is a diode; when the receiving end is started, the normally closed relay is controlled to be closed, the switching tube in the power converter is controlled to be closed so that the load is bypassed, and then the normally closed relay is controlled to be opened and the starting work of the receiving end is controlled, and the method specifically comprises the following steps: when the receiving end is started, the normally closed relay is controlled to be closed, and the controllable switching tube of the rectifier is controlled to be closed so that the load is bypassed; when the current of the transmitting coil of the transmitting end is determined to be larger than the first preset current, the switching state of the controllable switching tube is controlled according to the preset duty ratio.

With reference to the second aspect and any one of the foregoing possible implementation manners, in a tenth possible implementation manner, when the receiving end is turned off, controlling a switching tube in the power converter to be closed, then controlling the normally closed relay to be closed, so that the load is bypassed, and then controlling the receiving end to enter a shutdown state, specifically including: when the receiving end is shut down, when the current of the transmitting coil of the transmitting end is determined to be smaller than the second preset current and larger than the first preset current, the controllable switch tube is controlled to be closed, the normally closed relay is controlled to be closed, so that the load is bypassed, and the receiving end is controlled to enter a shut down state.

In a third aspect, an embodiment of the present application further provides a system for wireless charging, including: a transmitting end and a receiving end described above; the transmitting terminal comprises: the system comprises an inverter, a transmitting end compensation network, a transmitting coil and a transmitting end controller; the inverter inverts the direct current into alternating current and transmits the alternating current to the transmitting end compensation network; the transmitting end compensation network compensates the alternating current and then transmits the alternating current to the transmitting coil; the transmitting coil transmits the compensated alternating current in the form of an alternating magnetic field; a transmitting end controller for controlling the closing of a controllable switch tube of the inverter so as to enable the transmitting coil to generate the transmitting current required by the receiving end; the device is used for receiving a startup request or a shutdown request sent by a controller of the receiving end or sending the startup request or the shutdown request to the controller of the receiving end.

The system provided by the embodiment can prevent devices and loads of the receiving end from being damaged when the receiving end is started or shut down and the time sequence of the switching tube is uncontrollable, and can specifically control the switching tube in the power converter in the receiving end to bypass the loads, and can ensure that when a controller of the receiving end is not supplied with power, the loads are bypassed by using the normally closed relay connected with the output end of the compensation network in parallel, so that the system is realized, and the loads and the devices of the receiving end can be protected under the conditions that the controller of the receiving end is powered on and powered off.

Optionally, the transmitting end controller is further configured to send the current of the transmitting coil to the controller of the receiving end.

Compared with the prior art, the application has at least the following advantages:

when the receiving end is started, the controller controls the normally closed relay to be closed, and the switch tube in the power converter is closed, so that the load is bypassed, no current flows through the load, and therefore, the two ends of the load cannot have excessive voltage when the transmitting end is started, and the load is further protected from being damaged. The controller then controls the normally closed relay to be disconnected, and the receiving end starts to work for wireless charging. When the receiving end is shut down, the controller controls a switching tube in the power converter to be closed, the normally closed relay is closed, so that the load is bypassed, no current flows through the load, and then the controller controls the receiving end to enter a shut down state. Therefore, the two ends of the load cannot have excessive voltage when the transmitting end is powered off, and the load is further protected from being damaged when the transmitting end is powered off. In addition, when the load bypasses, the other half bridge arm of the rectifier is bypassed, so that no current flows through the other half bridge arm of the rectifier, and the two ends of the other half bridge arm cannot have excessive voltage when the transmitting end is started or shut down, so that the rectifier is protected, namely the receiving end is protected.

In summary, when the receiving end of wireless charging provided by the embodiment of the application is started or shut down, the states of the normally closed relay and the controllable switching tube in the power converter are controlled to bypass the load, so that stable conversion can be realized when the receiving end is started or shut down, the receiving end and the load are protected from being damaged, and the dual guarantee of load bypass is realized by controlling the normally closed relay and the controllable switching tube of the power converter.

Drawings

FIG. 1 is a schematic diagram of a wireless charging system;

fig. 2 is a schematic diagram of a wireless charging system for an electric vehicle according to the present application;

FIG. 3 is a block diagram corresponding to FIG. 2;

FIG. 4a is a schematic diagram of an LCC type compensation network according to the present application;

FIG. 4b is a schematic diagram of an LC-type compensation network according to the present application;

FIG. 4c is a schematic diagram of a P-type compensation network according to the present application;

FIG. 4d is a schematic diagram of an S-type compensation network according to the present application;

FIG. 5 is a schematic diagram of a wireless charging system with current source output according to the present application;

fig. 6 is a schematic system diagram corresponding to a receiving end provided by the present application;

fig. 7 is a schematic diagram of a full bridge rectifier at a receiving end according to the present application;

FIG. 8 is a control timing diagram of the receiving end in the power-on process of FIG. 7;

FIG. 9 is a control timing diagram of the receiving end in the shutdown process corresponding to FIG. 7;

FIG. 10 is another control timing diagram of the receiver shutdown process of FIG. 7;

fig. 11 is a schematic diagram of a system corresponding to another receiving end provided by the present application;

FIG. 12 is a power-on timing diagram corresponding to FIG. 11;

FIG. 13 is a shutdown timing diagram corresponding to FIG. 11;

FIG. 14 is a timing diagram of shutdown corresponding to FIG. 11;

fig. 15 is a schematic diagram of a system corresponding to another receiving end provided by the present application;

FIG. 16 is a power-on timing diagram corresponding to FIG. 15;

FIG. 17 is a shutdown timing diagram corresponding to FIG. 15;

FIG. 18 is a timing diagram of shutdown corresponding to FIG. 15;

fig. 19 is a schematic diagram of a system corresponding to a receiving end according to another embodiment of the present application;

FIG. 20 is a power-on timing diagram corresponding to FIG. 19;

FIG. 21 is a shutdown timing diagram corresponding to FIG. 19;

fig. 22 is a schematic diagram of a system corresponding to another receiving end provided in the present application;

FIG. 23 is a power-on timing diagram corresponding to FIG. 22;

FIG. 24 is a shutdown timing diagram corresponding to FIG. 22;

fig. 25 is a schematic diagram of a system corresponding to a receiving end according to another embodiment of the present application;

FIG. 26 is a timing diagram corresponding to FIG. 25;

FIG. 27 is a shutdown timing diagram corresponding to FIG. 25;

fig. 28 is a flowchart of a protection method when a wireless charging receiving end is started up according to an embodiment of the present application;

fig. 29 is a flowchart of a protection method when a wireless charging receiving end is turned off according to an embodiment of the present application;

fig. 30 is a schematic diagram of a wireless charging system according to an embodiment of the present application.

Detailed Description

In order to enable a person skilled in the art to better understand the technical scheme provided by the embodiment of the application, an application scenario of the wireless charging transmitting device is described first.

According to the wireless charging receiving end provided by the application, the alternating magnetic field sent by the transmitting end is wirelessly induced through the receiving coil and converted into direct current to charge the load, when the wireless charging receiving end and the wireless charging transmitting end are applied to the field of electric automobiles, the transmitting end is positioned on the ground, the receiving end is positioned on a vehicle, and the receiving end charges a vehicle-mounted power battery pack of the electric automobile. It is understood that wireless charging may be applied not only to electric vehicles, but also to other wireless charging scenarios, such as wireless charging for unmanned aerial vehicles. The following description will be given by taking an example of application to an electric vehicle.

Referring to fig. 2, the present application provides a schematic diagram of an electric vehicle wireless charging system.

The receiving end 1000a of wireless charging is located on the electric automobile 1000, and the transmitting end 1001a of wireless charging is located on the wireless charging station 1001 on the ground.

At present, the charging process of the wireless charging system is that the receiving end 1000a of wireless charging and the transmitting end 1001a of wireless charging complete the transmission of electric energy in a wireless mode to charge the power battery pack.

The wireless charging station 1001 may be a fixed wireless charging station, a fixed wireless charging parking space, a wireless charging road, or the like. The transmitting terminal 1001a for wireless charging may be disposed on the ground or buried under the ground (the case where the transmitting terminal 1001a for wireless charging is buried under the ground is shown in the figure).

The receiving terminal 1000a of wireless charging can be integrated in the bottom of the electric automobile 1000, when the electric automobile 1000 enters the wireless charging range of the transmitting terminal 1001a of wireless charging, the electric automobile 1000 can be charged in a wireless charging mode. The power receiving module and the rectifying circuit of the wireless charging receiving terminal 1000a may be integrated together or separated, which is not particularly limited in the present application, and when the power receiving module and the rectifying circuit are separated, a rectifier in the rectifying circuit is usually placed in a vehicle.

The power transmitting module of the wireless charging transmitting terminal 1001a and the inverter may be integrated together or may be separated. In addition, the non-contact charging may be that the receiving end 1000a of the wireless charging and the transmitting end 1001a of the wireless charging perform energy transmission through an electric field or magnetic field coupling manner, specifically, may be an electric field induction manner, a magnetic resonance manner, or a wireless radiation manner, which is not limited in particular in the embodiment of the present application. The electric vehicle 1000 and the wireless charging station 1001 may be charged in both directions, that is, the wireless charging station 1001 charges the electric vehicle 1000 through a charging power supply, or may discharge the charging power supply from the electric vehicle 1000.

Referring to fig. 3, the diagram is a structural diagram corresponding to fig. 2.

The figure shows a wireless charging transmitting terminal 1001a including: a transmission conversion module 1001a1, a power transmission module 1001a2, a transmission control module 1001a3, a communication module 1001a4, an authentication management module 1001a5, and a storage module 1001a6.

The receiving terminal 1000a for wireless charging includes: the power receiving module 1000a2, the receiving control module 1000a3, the receiving conversion module 1000a1, the vehicle communication module 1000a4, the energy storage management module 1000a5, and the energy storage module 1000a6. In addition, the receiving conversion module 1000a1 may be connected to the energy storage management module 1000a5 and the energy storage module 1000a6, and charge the energy storage module 1000a6 with the received energy, so as to be further used for driving the electric vehicle. The energy storage management module 1000a5 and the energy storage module 1000a6 may be located inside the wireless charging receiving terminal 1000a or outside the wireless charging receiving terminal 1000a, which is not limited in this embodiment of the present application. The power receiving module 1000a2 includes a receiving coil.

The transmission conversion module 1001a1 may be connected to an external power source, converting alternating current or direct current acquired from the external power source into high frequency alternating current, and when the input of the external power source is alternating current, the transmission conversion module 1001a1 includes at least a power factor correction unit and an inverter. When the input of the external power source is direct current, the transmission conversion module 1001a1 includes at least an inverter. The power factor correction unit is used for enabling the input current phase of the wireless charging system to be consistent with the voltage phase of the power grid, reducing the harmonic content of the wireless charging system, improving the power factor value, reducing the pollution of the wireless charging system to the power grid and improving the reliability. The power factor correction unit can also increase or decrease the output voltage of the power factor correction unit according to the later-stage requirements. The inverter converts the voltage output by the power factor correction unit into a high-frequency ac voltage, and then acts on the power transmission module 1001a2, and the high-frequency ac voltage can improve the transmission efficiency and the transmission distance. The external power source may be located inside or outside the wireless charging transmitting terminal 1001 a.

The power transmitting module 1001a2 is configured to transmit the alternating current outputted by the transmitting transforming module 1001a1 in the form of an alternating magnetic field. The power transmission module 1001a2 includes a transmission coil.

The transmission control module 1001a3 may control the voltage, current and frequency conversion parameter adjustment of the transmission conversion module 1001a1 according to the transmission power requirement of the actual wireless charging, so as to control the voltage and current output adjustment of the high-frequency ac power in the power transmission module 1001a 2.

The communication module 1001a4 and the vehicle communication module 1000a4 implement wireless communication between the transmitting terminal 1001a for wireless charging and the receiving terminal 1000a for wireless charging, including power control information, fault protection information, on-off information, mutual authentication information, and the like. On the one hand, the transmitting end 1001a of wireless charging may receive information such as attribute information, a charging request, and mutual authentication information of the electric vehicle sent by the receiving end 1000a of wireless charging; on the other hand, the transmitting terminal 1001a for wireless charging may also transmit wireless charging transmission control information, mutual authentication information, wireless charging history data information, and the like to the receiving terminal 1000a for wireless charging. Specifically, the Wireless communication manner may include, but is not limited to, any one or more of Bluetooth (Bluetooth), wireless-broadband (WiFi), zigbee (Zigbee), radio Frequency Identification (RFID) technology (Radio Frequency Identification), long Range (Long Range) Wireless technology, and near field communication (Near Field Communication, NFC). Further, the communication module 1001a4 may also communicate with an intelligent terminal of the user of the electric automobile, where the user realizes remote authentication and user information transmission through a communication function.

The authentication management module 1001a5 is used for interactive authentication and authority management of the transmitting terminal 1001a and the electric automobile in wireless charging in the wireless charging system.

The storage module 1001a6 is configured to store charging process data, interaction authentication data (e.g. interaction authentication information), and rights management data (e.g. rights management information) of the transmitting end 1001a of wireless charging, where the interaction authentication data and the rights management data may be factory setting or user setting, and the embodiment of the application is not limited in particular.

The power receiving module 1000a2 receives electromagnetic energy emitted from the power emitting module 1001a2 in the form of an alternating magnetic field. The combination of the power transmitting module 1001a2 and the compensation circuit of the power receiving module 1000a2 in the wireless charging system includes S-S type, P-P type, S-P type, P-S type, LCL-LCL type, LCL-P type, LCC-LCC type, and the like, which is not particularly limited in the embodiment of the present application. The wirelessly charged transmitting terminal 1001a and the wirelessly charged receiving terminal 1000a may be in roles interchanged, i.e. the wirelessly charged receiving terminal 1000a may also charge the wirelessly charged transmitting terminal 1001a in reverse.

The receiving conversion module 1000a1 converts electromagnetic energy received by the power receiving module 1000a2 into direct current required for charging the energy storage module 1000a 6. The receiving conversion module 1000a1 includes at least a compensation circuit and a rectifier, wherein the rectifier converts the high frequency resonant current and voltage received by the power receiving module into direct current.

The receiving control module 1000a3 can adjust parameters such as voltage, current, frequency, etc. of the receiving conversion module 1000a1 according to the receiving power requirement of the actual wireless charging.

The output characteristic of the wireless charging system can be a current source characteristic or a voltage source characteristic, and is mainly determined by the compensation networks of the transmitting end and the receiving end.

With particular reference to the schematic structural diagrams of the various compensation networks shown in fig. 4 a-4 d.

Taking the compensation network of the transmitting end shown in fig. 4 a-4 d as an example, lp in each figure is the transmitting coil.

L1, C1 and Cp in fig. 4a form an LCC type compensation network.

L1 and C1 in fig. 4b form an LC-type compensation network.

In fig. 4C, C1 and Lp are Parallel structures (parallels) forming a P-type compensation network.

Cp and Lp in FIG. 4d are Series structures (Series) forming an S-type compensation network.

The compensation network of the receiving end is similar to that of the transmitting end, and the compensation networks of the transmitting end and the receiving end are generally symmetrical structures, which are not described herein. The common combination of a compensation network and a coil for a transmitting end and a receiving end, which can make the output of a wireless charging system present a current source characteristic, comprises: LCCL-LCCL, LCL-LCL, LCCL-LCL, LCL-LCCL, LCCL-P, LCL-P, S-S, and the like. Taking LCCL-LCCL as an example, the first LCCL is a combination of a compensation network and a transmitting coil at a transmitting end, and the second LCCL is a combination of a compensation network and a receiving coil at a receiving end.

Referring to fig. 5, a schematic diagram of a wireless charging system with current source output is provided in the present application. The wireless charging transmitting end, receiving coil Ls and receiving end compensation network 200 are equivalent to equivalent current sources, and the rectifier H2 and load are equivalent to equivalent loads R of the current sources.

When the output of the wireless charging system is a current source, the voltage across the equivalent load R is only related to the current magnitude i of the equivalent current source. When the current i of the equivalent current source is determined, the voltage u=i×r across the equivalent load. The equivalent current source is characterized in that the magnitude of the output current does not change with the change of the load, so that the load is required to be unable to open. Because the equivalent load R is large when the load is open, the voltage U across the equivalent load is much greater than normal, damaging the load and the receiving end, and even causing the receiving end fryer.

In order to solve the technical problems, the application provides a wireless charging receiving end, when the receiving end is started, a controller of the receiving end controls a switch tube in a power converter to be closed so as to bypass a load, no current flows through the load no matter whether the load is in an open circuit state or not, and therefore, the two ends of the load cannot have too high voltage when the transmitting end is started, and further the load is protected from damage. The controller then controls the receiving end to start working to perform wireless charging. When the receiving end is shut down, the controller controls the switching tube in the power converter to be closed so that the load is bypassed, no current flows through the load no matter whether the load is in an open circuit state or not, and therefore, the two ends of the load cannot have too high voltage when the transmitting end is shut down, and further, the load is protected from being damaged when the transmitting end is shut down. And then controlling the receiving end to enter a shutdown state.

In summary, the receiving end for wireless charging provided by the application can protect the receiving end and the load from being damaged when the receiving end is started or shut down, thereby improving the safety of the wireless charging system.

In order to enable those skilled in the art to better understand the present application, the following description will clearly describe the technical solution in the present embodiment of the present application with reference to the accompanying drawings in the present embodiment. It is to be understood that the words "first" and "second" and the like in the following embodiments are merely for convenience of explanation and do not constitute a limitation of the present application.

Receiving end embodiment one:

referring to fig. 6, the system schematic diagram corresponding to the receiving end provided by the embodiment of the application is shown.

The wireless charging receiving terminal provided in this embodiment includes: a receiving coil Ls, a receiving side compensation network 200 (hereinafter referred to as compensation network 200), a power converter and a receiving side controller 201.

The power converter may include only the rectifier H2, or may include the rectifier and the DC-DC circuit, and the following description will take the power converter including only the H2 as an example, and the following embodiments describe an implementation manner in which the power converter includes the rectifier and the DC-DC circuit.

The receiving coil Ls converts the alternating magnetic field emitted from the transmitting end into alternating current and transmits the alternating current to the compensation network 200.

The compensation network 200 compensates the alternating current and then supplies the alternating current to the rectifier H2.

The receiving-end controller 201 controls the controllable switching transistor of the rectifier H2.

The normally closed relay SW is connected in parallel with the output end of the compensation network 200; since SW is a normally closed relay, it is closed when there is no drive signal and open when there is a drive signal. During normal charging, the receiving end controller 201 may control SW to be turned off, and during the switching on/off process, the receiving end controller 201 may control SW to be turned on in order to bypass the load and bypass the output end of the compensation network 200.

The rectifier H2 rectifies the compensated ac power into dc power to be supplied to the load.

The compensation network 200 is a compensation circuit with a current source characteristic, so that the receiving coil Ls and the compensation network 200 make the input end of the rectifier H2 be a constant current source under the combined action of the transmitting end, and the transmitting end compensation network 100 and the receiving end compensation network 200 may adopt the above compensation network, which is not described herein again in the embodiments of the present application. The rectifier H2 and the load form an equivalent load, so that the current i input to the rectifier H2 is independent of the impedance of the equivalent load.

In order to prevent the problem of the switching tube of the rectifier from generating a load open circuit in the starting or shutting process, the receiving end controller of the application realizes the bypass of the load when the rectifier is started or shut down by controlling the normally closed relay connected in parallel with the output end of the compensation network and controlling the state of the switching tube of the rectifier, and the working principle of the controller is specifically described below. The bypass to the load during the startup process or the bypass to the load during the shutdown process is within the protection scope of the application.

Wherein, start up means: transition from "standby state" or "off state" to "charge state". Shutdown refers to: transition from "state of charge" to "standby state" or "off state".

In practical application, when the receiving end is converted from the "off state" to the "charging state", the receiving end can be firstly converted from the "off state" to the "standby state" and then converted from the "standby state" to the "charging state".

The transition from the "charge state" to the "standby state" is a normal shutdown, and when the auxiliary power supply (not shown in the figure) at the receiving end is powered down, the auxiliary power supply cannot supply power to the controller, in which case the controller needs to be brought into the "shutdown state" from the "charge state" or the "standby state".

When the receiving end is started, the receiving end controller controls the normally closed relay to be closed, and the load is bypassed by controlling the first part of switching tubes in the rectifier H2 to be closed; the first part of switching tubes may be switching tubes of an upper half bridge arm or switching tubes of a lower half bridge arm in the rectifier H2. The receiving end controller sends a PWM (Pulse width modulation ) driving signal to each controllable switching tube of the rectifier H2 to control the switching state of each switching tube.

The rectifier H2 may be a full-bridge rectifier or a half-bridge rectifier, and when the rectifier H2 is a full-bridge rectifier, two bridge arms are included, so two upper half bridge arms and two lower half bridge arms are correspondingly included. When the rectifier H2 is a half-bridge rectifier, it includes one bridge arm, and thus includes one upper half bridge arm and one lower half bridge arm, respectively.

In fig. 7, taking the rectifier H2 including four controllable switching tubes S1-S4 as an example, the receiving end controller 201 may control SW to be turned on, and switch tubes S1 and S3 of the upper half bridge arm of the H2 to be turned on, or control switch tubes S2 and S4 of the lower half bridge arm to be turned on, at this time, the load is bypassed, the output end of the compensation network 200 is shorted, and no current flows through the load, so that there is no excessively high voltage at two ends of the load when the transmitting end is turned on, and the load and the receiving end are protected from being damaged.

When the receiving end controller 201 confirms that the switching tube of the upper half bridge arm or the switching tube of the lower half bridge arm of the rectifier H2 is closed, the SW is controlled to be opened, and the receiving end is controlled to start working, namely, the rectifier H2 is controlled to enter a normal rectifying state to charge the load.

Specifically, the receiving end controller 201 may also notify the transmitting end of the wireless charging to start the wireless charging procedure. In practical applications, the receiving-end controller 201 may send a charging request to the communication module of the transmitting end through the communication module of the receiving end, so as to indicate that the receiving end has completed the preparation work of wireless charging, and the transmitting end may start the flow of wireless charging. The communication module of the transmitting end may notify the transmitting end controller 101 to start the flow of wireless charging when receiving the charging request.

When the receiving end is turned off, the receiving end controller 201 controls the second part of switching tubes in the rectifier H2 to be closed, and then controls the SW to be closed so that the load is bypassed; and then controlling the receiving end to enter a shutdown state. The second part of switching tubes are switching tubes of an upper half bridge arm or a lower half bridge arm of the rectifier in the rectifier H2. Because the state of SW is open before shutdown, when shutdown, SW needs to be controlled to be closed, and the output end of the compensation network is short-circuited.

The receiving end shutdown refers to that the receiving end controller receives a shutdown instruction or receives an alarm of the power failure fault of the auxiliary power supply, and the receiving end controller needs to be shut down.

When the full-bridge rectifier H2 shown in fig. 7 includes controllable switching transistors S1-S4, when the receiving end is turned off, the receiving end controller 201 controls the switching transistors S1 and S3 of the upper half bridge arm to be closed, or controls the switching transistors S2 and S4 of the lower half bridge arm to be closed, and controls SW to be closed, at this time, the load is bypassed, no current flows through the load, so that the two ends of the load cannot have too high voltage when the transmitting end is turned on, and the load and the receiving end are protected from being damaged.

When the receiving end is started or shut down, in order to improve the safety of the wireless charging system, when the two upper half bridge arms of the rectifier H2 both comprise controllable switching tubes, the receiving end controller 201 controls the controllable switching tubes of the two upper half bridge arms to be closed simultaneously, so long as the driving signals of the controllable switching tubes of the two upper half bridge arms are kept synchronous. When the two lower half bridge arms of the rectifier H2 each include a controllable switching tube, the receiving end controller 201 controls the controllable switching tubes of the two lower half bridge arms to be closed at the same time, so long as the driving signals of the two controllable switching tubes are kept synchronous.

It is understood that the receiver-side controller provided in the present application may be located in the receiver control module 1000a3 in fig. 3.

The type of controllable switching tube can be any one of the following: a relay, an insulated gate bipolar transistor (Insulated Gate Bipolar Transistor, IGBT) or a metal oxide semiconductor field effect transistor (Metal Oxide Semiconductor Filed Effect Transistor, MOSFET, hereinafter referred to as MOS transistor), a silicon carbide metal oxide semiconductor field effect transistor (Silicon Carbide Metal Oxide Semiconductor Filed Effect Transistor, siC MOSFET, etc., wherein, when the switching transistor is a MOS transistor, the switching transistor may be a PMOS transistor or an NMOS transistor, which is not particularly limited in the embodiment of the present application.

According to the wireless charging receiving end provided by the embodiment of the application, when the receiving end is started, the controller controls the normally closed relay to be closed, and controls the switching tube of the upper half bridge arm or the switching tube of the lower half bridge arm of the rectifier to be closed, so that a load is bypassed, no current flows through the load, and therefore, the two ends of the load cannot have too high voltage when the transmitting end is started, and the load is further protected from damage. The controller then controls the normally closed relay to be disconnected, and the receiving end starts to work for wireless charging. When the receiving end is shut down, the controller controls the switching tube of the upper half bridge arm or the switching tube of the lower half bridge arm of the rectifier to be closed, the normally closed relay is closed, so that the load is bypassed, no current flows through the load, and then the controller controls the receiving end to enter a shut down state. Therefore, the two ends of the load cannot have excessive voltage when the transmitting end is powered off, and the load is further protected from being damaged when the transmitting end is powered off. In addition, when the load is bypassed, the other half bridge arm of the rectifier is bypassed, so that no current flows through the other half bridge arm of the rectifier, and the two ends of the other half bridge arm cannot have excessive voltage when the transmitting end is started or shut down, so that the rectifier is protected, namely the receiving end is protected.

In summary, when the receiving end of wireless charging provided by the embodiment of the application is started or shut down, the state of the controllable switching tube in the normally closed relay and the rectifier is controlled to bypass the load, so that stable conversion can be realized when the receiving end is started or shut down, the receiving end and the load are protected from being damaged, and the double guarantee of load bypass is realized by controlling the normally closed relay and the controllable switching tube of the rectifier.

The rectifier provided by the embodiment of the application only comprises a switching tube, and the bypass of the load is realized by controlling the switching tube, and the rectifier can be a full-bridge rectifier or a half-bridge rectifier, wherein the full-bridge or the half-bridge can only comprise a controllable switching tube or a combination of the controllable switching tube and a diode, and various realization forms of the rectifier are respectively described below.

A second receiving-end embodiment:

the following description will be made by taking an example in which the rectifier includes two bridge arms, and the switching tubes of the upper half bridge arm and the lower half bridge arm of each bridge arm are controllable switching tubes. In fig. 7, S1 and S2 are located in the same arm, S3 and S4 are located in the same arm, S1 and S3 are located in the upper half arm, and S2 and S4 are located in the lower half arm.

With continued reference to fig. 7, the system diagram corresponding to another wireless charging receiving end according to the embodiment of the present application is shown.

The transmitting terminal provided in this embodiment includes: inverter H1, transmitting-side compensation network, transmitting coil Lp, and transmitting-side controller 101.

The receiving end comprises: a receiving coil Ls, a receiving end compensation network, a rectifier H2, an output filter capacitor Co, a load and receiving end controller 201.

Fig. 7 illustrates an example of a combination of a compensation network and coils at the transmitting and receiving ends as LCCL-LCCL. The transmitting end compensation network comprises L1, C1 and Cp, and is an LCC type compensation network; the receiving-end compensation network comprises L2, C2 and Cs, and is also an LCC type compensation network, so that the output of the wireless charging system is in a current source characteristic.

In practical application, the combination of the compensation network and the coils of the transmitting end and the receiving end can also adopt LCL-LCL, LCCL-LCL, LCL-LCCL, LCCL-P, LCL-P, S-S and other combinations, and when any combination is applied, the control principle of the controller of the receiving end is similar, and the description is omitted here.

The receiving end controller 201 controls the output voltage (or output current or output power) of the system, and can generate a current reference signal of the transmitting coil to control the on and off of the switching tube of the rectifier H2. The transmitting end controller 101 controls the on and off of the switching tube of the inverter H1 to control the current of the transmitting coil.

The following specifically describes the control sequence of the receiving-side controller to the SW and the controllable switching tube of the rectifier H2 during the power-on and power-off of the receiving-side.

First, the control principle of the receiver controller when the receiver is powered on will be described with reference to fig. 7 and 8.

Referring to fig. 8, a control timing diagram of a receiving end in a power-on process according to a second embodiment of the present application is shown.

The receiving terminal is turned on, that is, the receiving terminal is switched from the "standby state" or the "off state" to the "charging state", and the following description will take the receiving terminal switched from the "standby state" to the "charging state" as an example. When the wireless charging system is in a standby state, the auxiliary power supply of the receiving end is in a working state, and the auxiliary power supply of the transmitting end is also in a working state.

In the "standby state", when the receiving end receives the charging instruction, the receiving end controller 201 sends a charging request to the transmitting end through the wireless communication module of the receiving end, and the transmitting end controller 101 receives the charging request through the wireless communication module of the transmitting end and responds to enable the wireless charging system to start a charging process.

The receiving end controller 201 controls the controllable switching tubes S1 and S3 of the two upper half bridge arms of H2 to be closed, or controls the controllable switching tubes S2 and S4 of the two lower half bridge arms to be closed, so as to bypass the load. In the embodiment of the present application, the receiving end controller 201 controls the switching tubes S2 and S4 of the two lower half bridge arms of the rectifier H2 to be closed, and the switching tube is turned on when the driving signal of the controllable switching tube is at a high level, and turned off when the driving signal of the controllable switching tube is at a low level. Because one end of S2 and one end of S4 are grounded, the control is convenient.

In the "standby state", the relay SW connected in parallel to the output end of the receiving-end compensation network is in a closed state to bypass the rectifier H2 and the load, corresponding to the low level of SW in fig. 8.

When the transmitting end completes soft start, the current of the transmitting coil current is larger than the first preset current, the corresponding current is induced on the receiving coil, the receiving end controller 201 controls the phase shift angle of the rectifier to be zero, and the driving of the upper and lower switching tubes reserves enough dead time, corresponding to the high-low level jump process of S1-S4 before the broken line of the 'protection switch' in FIG. 8. The driving signals of S1 and S3 are completely synchronous, the driving signals of S2 and S4 are completely synchronous, the driving signals of S1 and S3 are complementary with the driving signals of S2 and S4, the driving signals correspond to 50% duty ratio respectively, and the receiving end completes charging preparation.

The receiving end completes the charge preparation, the receiving end controller 201 outputs the driving signal of the SW, after the "protection switch is turned off" dashed line, the SW has a certain off time Tr, and under the condition of guaranteeing that the SW is completely turned off (for example, about 10 ms), the phase shift angle of the front bridge arm and the rear bridge arm of the rectifier is gradually increased to a preset value, and the wireless charging system starts to work normally.

And the corresponding diagram is that the protection switch is disconnected, and the high-low level jump process of S1-S4 is carried out after Tr is completed. The driving signals of S1 and S3 are complementarily conducted with the driving signals of S2 and S4, and the phase shifting angle theta is gradually increased to a required value by S1 and S3, so that the starting-up process is completed.

The first preset current value and the preset value of the phase shift angle may be set according to actual situations, and the embodiment of the present application is not specifically limited herein.

The following describes the control principle of the receiver controller when the receiver is turned off.

Referring to fig. 9, the control sequence of the receiver shutdown process corresponding to fig. 7 is shown. In the "state of charge", the receiving end receives the shutdown instruction, or receives the fault alarm of the auxiliary power supply power failure, the receiving end controller 201 sends the shutdown instruction to the transmitting end controller 101 through the wireless communication module, the shutdown process is started, the transmitting end gradually reduces the transmitting coil current to be smaller than the second preset current and larger than the first preset current, the receiving end controller 201 controls the phase shift angle between the two bridge arms to gradually reduce until the switching tubes of the upper half bridge arm of the rectifier are closed or the switching tubes of the lower half bridge arm are closed, so that the load is bypassed, and then the receiving end is controlled to enter the shutdown state.

Specifically, referring to the timing chart, the driving signals of S1-S4 in H2 are controlled, the phase shift angle of S1 and S3 is gradually reduced from a certain phase shift angle θ to 0, that is, the driving signals of S1 and S3 are completely synchronized, the driving signals of S2 and S4 are completely synchronized, the driving signals of S1 and S3 are complementarily conducted with the driving signals of S2 and S4, and the jump corresponds to the high-low level before the "protection switch is closed" in fig. 9.

After the phase shift angles of the rectifiers S1 and S3 are 0, the SW connected in parallel to the output end of the compensation network is closed, and the driving signal corresponding to SW in fig. 9 is changed from high level to low level. After ensuring that SW is fully closed, the transmitting end gradually reduces the transmit current until the transmit current ceases. The receiving end stops sending the driving signals of the rectifiers S1-S4, and the driving signals corresponding to the "standby state" areas S2 and S4 in fig. 9 are changed from high level to low level.

There are two common ways of driving signals of the rectifiers S1-S4, as shown in fig. 9, in which two upper tubes or two lower tubes are kept on for a long time after the phase shift angle θ of S1 and S3 is reduced to zero, and the other two switching tubes of the same bridge arm are kept off for a long time. As shown in fig. 10, the second mode gradually reduces the phase shift angle θ of S1 and S3 to zero, and the upper tube and the lower tube are turned on with a duty ratio of 50%, and the second mode requires to control the dead time between the upper tube and the lower tube and continuously switch the switch state, so that the control is relatively complex, and relatively, the driving signal adjustment mode of the first mode is relatively simple and easy to control.

The rectifier in the receiving end provided by the embodiment of the application comprises two bridge arms, and the switching tubes are controllable switching tubes. Because the input end of the rectifier can be equivalently a current source, the over-high voltage at the two ends of the load can be caused when the load is opened so as to possibly damage the load and the receiving end, when the receiving end is started or shut down, the receiving end controller controls the normally closed relay connected with the output end of the compensation network to be closed, and controls the switching tubes of the two upper half bridge arms or the switching tubes of the two lower half bridge arms of the rectifier to be closed so that the load is bypassed, namely no current flows through the load, and the two ends of the load cannot have the over-high voltage when the transmitting end is started so as to protect the load from being damaged. In addition, the other half bridge arm of the rectifier is bypassed, so that no current flows through the other half bridge arm, and therefore, the two ends of the other half bridge arm cannot have excessive voltage when the transmitting end is started, so that the rectifier is protected, namely the receiving end is protected.

A third receiving-end embodiment:

two field effect transistors are also connected in parallel at the two ends of the normally closed relay, and a structure in which the rectifier includes a diode and a controllable switching tube is described as an example. In this embodiment, the compensation network and the coil form an LCL-LCL structure, which determines the current source characteristic of the input terminal of the rectifier.

Referring to fig. 11, a system schematic diagram corresponding to another receiving end according to an embodiment of the present application is shown.

The difference between the embodiment and the second embodiment is that a bidirectional field effect transistor connected in parallel with two ends of the SW is added, the bidirectional field effect transistor is formed by reversely connecting two field effect transistors SW1 and SW2 in series, and the two field effect transistors adopt the same driving signal.

In addition, in the present embodiment, the rectifier is illustrated by taking the switching tubes in the two lower half bridge arms as controllable switching tubes S2 and S4, and the switching tubes in the two upper half bridge arms as diodes D1 and D3 as examples, and at this time, when the receiving end is turned on or turned off, a bypass load is required, and the bypass load is realized by controlling the switching tubes S2 and S4 of the two lower half bridge arms in the rectifier.

The working principle is described below with reference to a power-on control timing chart corresponding to fig. 12.

When the receiving end is started, the receiving end controller 201 firstly controls the normally-closed relay SW to be disconnected, and then controls the field effect transistors SW1 and SW2 to be disconnected.

Starting time sequence:

in the "standby state", the SW connected in parallel to the output end of the receiving-end compensation network is in a closed state, so as to bypass the rectifier H2 and the load, and the driving signal of the SW before the "rectifier switching on of the wave-generating S2 and S4" dashed lines in fig. 12 is in a low level state, and the driving signal of the SW1 and the SW2 is in a low level state.

Until the transmitting end finishes soft start, when the current of the transmitting coil is larger than a first preset current, the receiving coil induces the current, the receiving end controller sends out the phase shift angle of the driving signals of the rectifiers S2 and S4 to be 0, and strictly ensures that the phase shift angle is zero, and corresponds to the process of jumping the S2 and S4 from low level to high level and keeping the high level after the 'rectifier wave-generating S2 and S4 are conducted' in the broken line in fig. 12. The drive signals of S2 and S4 are fully synchronized and are turned on until a charged state is entered.

The receiving end completes the charge preparation, and the receiving end controller sends out the driving signals of SW1 and SW2, so that both SW1 and SW2 are turned on, corresponding to the time when the driving signals in the "standby state" areas SW1 and SW2 change from low level to high level in fig. 12. After SW1 and SW2 are turned on, a drive signal of SW is issued, corresponding to the timing when the drive signal of SW changes from low level to high level in the "standby state" region SW in fig. 12. The drive signal of SW is always kept at high level, and SW1 and SW2 are turned off after a certain time to ensure complete turn-off of SW, changing from high level to low level. After SW1 and SW2 are turned off, the duty ratio of the driving signals of the switching transistors S2 and S4 is gradually adjusted to a preset value, so that the wireless charging system starts to work normally.

The preset values of the first preset current and the duty cycle may be set according to actual situations, which is not particularly limited in the embodiment of the present application.

Shutdown sequence:

the operation principle is described below with reference to the shutdown control timing chart corresponding to fig. 13.

When the receiving end receives a shutdown instruction in a charging state or receives a fault alarm of power failure of the auxiliary power supply, the receiving end controller sends the shutdown instruction to the transmitting end controller through the wireless communication module, the shutdown process is started, and when the current of the transmitting end gradually reduces the transmitting coil to be smaller than a second preset current and larger than the first preset current, the receiving end performs corresponding operation.

The receiving end controller adjusts the driving signals of S2 and S4 of the rectifier, the driving signals of S2 and S4 are completely synchronous from different duty ratios to the same duty ratio, and the driving signals of S2 and S4 are kept at high level, corresponding to the high level after the broken line of 'S2 and S4 are always kept on' in fig. 13.

After the phase shift angles of S2 and S4 are 0, the SW1 and the SW2 are controlled to be closed, and after the SW1 and the SW2 are closed, the driving signal of the SW is controlled to be changed into a low level, and the driving signal corresponding to the SW in FIG. 13 is changed from high to low and the corresponding SW is closed. After ensuring that SW is fully closed, SW1 and SW2 are turned off, and the driving signals of SW1 and SW2 are changed from high level to low level. The transmitting end gradually reduces the current of the transmitting coil until the transmitting current is stopped. The receiving-end controller stops the driving signals of the signals S2 and S4, and the driving signals corresponding to the "standby state" areas S2 and S4 in fig. 13 are changed from the high level to the low level. In the sequence shown in fig. 13, after the shutdown is completed, SW1 and SW2 remain in the open state, SW remains in the closed state,

in addition, in the shutdown timing, SW1 and SW2 are controlled in another way, as shown in fig. 14, the driving signals of SW1 and SW2 are always kept in the high-level state after being changed from the low level to the high level, that is, SW1 and SW2 are simultaneously in the closed state with SW. Fig. 13 shows that the relay can be kept closed even without an auxiliary power supply, and the controller is not required to be operated again, and fig. 14 shows that the controller is operated all the time, and the standby power consumption is slightly larger, but the standby power consumption is also a mode which can be reserved.

In the above embodiments, the power-on time refers to the power-on process, and the power-off time refers to the power-off process. And when the charging after the starting-up is steady, SW1, SW2 and SW are all disconnected. When the device is in a steady state after shutdown, SW1, SW2 and SW are all closed, or SW1 and SW2 are opened and SW is closed.

A fourth receiving-end embodiment:

another implementation manner of connecting other switching devices in parallel to two ends of the normally closed relay is described below, and in this embodiment, the power converter includes a rectifier and a DC-DC circuit, where all the rectifiers are diodes, and when the power converter is turned on and off, a load is bypassed by controlling a switching tube in the DC-DC circuit. The compensation network and the coil form an LCL-P structure, and the structure determines that the input end of the rectifier presents current source characteristics.

Referring to fig. 15, a system schematic diagram corresponding to another receiving end according to an embodiment of the present application is shown.

In this embodiment, the DC-DC circuit is a boost circuit formed by an inductance Lb, a diode Db, and a switching tube Qb. In addition, the DC-DC circuit may be other circuits including a controllable switching transistor, and the embodiment is not particularly limited.

In this embodiment, two ends of SW are connected in parallel with a bidirectional controllable switch, as shown in fig. 15, where the bidirectional controllable switch includes four diodes d1-d4 and a controllable switch tube SW1.

Starting time sequence:

referring to fig. 16, the power-on timing chart corresponding to fig. 15 is shown.

In the "standby state", the SW connected in parallel to the output end of the receiving-end compensation network is in a closed state, and the rectifier and the load are bypassed, corresponding to the low level state of SW and the low level state of SW1 before the "direct current conversion circuit Qb is turned on" in fig. 16.

Until the transmitting end completes soft start, when the current of the transmitting coil is larger than the first preset current, the receiving coil induces current, and the receiving end controller sends out a Qb normally-on driving signal, which corresponds to the process of jumping the Qb driving signal from low level to high level and keeping high level after the direct current conversion circuit Qb is conducted in a dotted line in fig. 16. Qb remain on until a state of charge is entered.

The receiving end completes the charge preparation, and the receiving end controller sends out a driving signal of SW1 to make SW1 be turned on, corresponding to the time when the driving signal of SW1 changes from low level to high level in the "standby state" area in fig. 16. The driving signal of SW is emitted after SW1 is turned on, corresponding to the timing when the driving signal of SW changes from low level to high level in the "standby state" region SW in fig. 16. The SW drive signal is always kept at a high level, and SW1 is turned off after a certain time to ensure complete turn-off of SW, and is changed from a high level to a low level. When SW1 is turned off, the duty ratio of Qb is gradually adjusted to a preset value so that the wireless charging system starts to work normally.

Shutdown sequence:

referring to fig. 17, a shutdown timing diagram corresponding to fig. 15 is shown.

When the receiving end receives a shutdown instruction in a charging state or receives a fault alarm of power failure of the auxiliary power supply, the receiving end controller sends the shutdown instruction to the transmitting end controller through the wireless communication module, the shutdown process is started, and when the current of the transmitting end gradually reduces the transmitting coil to be smaller than a second preset current and larger than the first preset current, the receiving end performs corresponding operation. The timing of the shut down process is shown in fig. 17.

The receiving end controller adjusts the driving signal of Qb gradually from the duty ratio smaller than 1 to the duty ratio equal to 1, that is, the control Qb is always on, corresponding to the high level after the "direct current conversion circuit Qb is turned on" in fig. 17.

After Qb is normally on, SW1 is turned on, and the driving signal for controlling SW is turned to low level, corresponding to the driving signal of SW in fig. 17 being turned from high level to low level. After ensuring that SW is fully closed, SW1 is turned off, and the drive signal of SW1 is changed from high level to low level. The transmitting end gradually reduces the current of the transmitting coil until the transmitting current is stopped. The receiving-end controller stops the driving signal of the transmitting rectifier Qb, and the driving signal is changed from high level to low level corresponding to the "standby state" area Qb in fig. 17.

In the shutdown timing, in the standby state, as shown in fig. 18, the SW1 is still in the high state after the driving signal of the SW1 is changed from the low level to the high level, i.e., the SW1 and the SW are simultaneously in the closed state.

Fifth, the receiving end embodiment:

the rectifiers described in the above embodiments are all full-bridge rectifiers, and the following describes an implementation in which the rectifier is a half-bridge, i.e. includes only one bridge arm.

Referring to fig. 19, a system schematic diagram corresponding to a receiving end provided by the present application is shown.

In this embodiment, a normally closed relay SW is connected in parallel to the output end of the compensation network, and other switching devices may be connected in parallel to the two ends of the SW, as in the third and fourth embodiments of the receiving end, which will not be described herein.

The switch state of SW is the same as that of the receiving end, the inverter of the transmitting end is a half-bridge structure formed by switch tubes Q1 and Q2, the rectifier of the receiving end comprises two controllable switch tubes S1 and S2, the compensation network and the coil form an S-S structure, and the structure determines that the input end of the rectifier is in a current source characteristic.

The power-on and power-off processes of the embodiment of the present application are the same as those of the first embodiment, and the power-on time sequence of the power-on process is shown in fig. 20.

Starting time sequence:

SW is in a closed state (low level), and control S2 is turned on (high level) so that the load is bypassed. When SW is turned off (changed from low level to high level) after completion of the charge preparation work and SW is guaranteed to be completely turned off, driving of S1 and S2 is normally performed to wirelessly charge the load.

Shutdown sequence:

referring to fig. 21, a shutdown timing diagram of the receiving end corresponding to fig. 19 is shown.

The driving signal of the rectifier is first adjusted so that S2 remains on (high level) and S1 remains off (low level), in which case SW is closed (high level to low level), and after SW is fully closed, S2 is turned off (high level to low level).

The embodiment also provides another receiving end, wherein the rectifier is also a half-bridge, i.e. only comprises one bridge arm, but the upper bridge arm is a diode, and the lower bridge arm is a controllable switch tube.

As shown in fig. 22, the rectifier includes a diode D1 and a controllable switching tube S2. The rest is the same as the receiving end shown in fig. 18.

The control of the power-on and power-off timing of the receiving end shown in fig. 22 is the same as the timing of removing the bidirectional switch tube in the third embodiment of the receiving end, and the power-on timing diagram shown in fig. 23 and the power-off timing diagram shown in fig. 24 are not repeated here.

Receiving side embodiment six:

another implementation of the power converter is described below, which corresponds to two Boost circuits being interleaved in parallel.

Referring to fig. 25, a system schematic diagram corresponding to a receiving end according to another embodiment of the present application is shown.

In this embodiment, the compensation network and the coils of the transmitting end and the receiving end form an LCL-LCCL structure, which determines that the input end of the rectifier presents a current source characteristic.

The receiving end comprises two controllable switching tubes Qb1 and Qb2.

The receiving end comprises a normally closed relay SW connected in parallel with the output end of the compensation network, and when the receiving end is started and shut down, the control and implementation of the SW are the same, and the description is omitted here.

Other switching devices connected in parallel to SW in the third and fourth receiving end embodiments are also applicable to this embodiment, and will not be described here again.

The power-on and power-off processes of the present embodiment are the same as those of the second embodiment.

Starting time sequence:

referring to fig. 26, SW is in a closed state (low level), qb1 and Qb2 are simultaneously turned on (high level), and SW is turned off (changed from low level to high level) after the completion of the charge preparation operation, so that the duty ratio of Qb1 and Qb2 is gradually adjusted to satisfy the power output under the condition that SW is ensured to be completely turned off, and the load is charged.

Shutdown sequence:

referring to fig. 27, qb1 and Qb2 are adjusted stepwise by normal on-off of Qb1 and Qb2 while being on (high level), in which case SW is turned on (changed from high level to low level), and Qb1 and Qb2 are turned off (changed from high level to low level) after SW is completely turned on.

Method embodiment:

based on the receiving end provided by the above embodiment, the embodiment of the present application further provides a protection method for wireless charging, and the following detailed description is given with reference to the accompanying drawings.

The protection method for wireless charging provided in this embodiment is applied to the receiving end for wireless charging, and specific reference may be made to the above embodiment of the receiving end, and this embodiment is not described herein again. The receiving end comprises: a receiving coil, a power converter and a normally closed relay; the compensation network is a compensation circuit with a current source characteristic, so that the receiving coil and the compensation network make the input end of the rectifier be a constant current source under the combined action of the transmitting end. The method comprises the following steps:

When the receiving end is started, the normally closed relay is controlled to be closed, a load is bypassed by controlling a switching tube in the power converter to be closed, and then the normally closed relay is controlled to be opened and the starting work of the receiving end is controlled;

or alternatively, the first and second heat exchangers may be,

when the receiving end is shut down, a switching tube in the power converter is controlled to be closed, then the normally closed relay is controlled to be closed, so that the load is bypassed, and then the receiving end is controlled to enter a shut-down state.

Specifically, when the receiving end is started, the normally closed relay is controlled to be closed, and the load is bypassed by controlling the switching tube in the power converter to be closed, which specifically comprises:

when the receiving end is started, the normally closed relay is controlled to be closed, and the load is bypassed by controlling the first part of switching tubes in the power converter to be closed;

when the receiving end is shut down, the normally closed relay is controlled to be closed by controlling a switching tube in the power converter to be closed, so that the load is bypassed, and the method specifically comprises the following steps:

when the receiving end is shut down, the second part of switching tube in the power converter is controlled to be closed, and then the normally closed relay is controlled to be closed, so that the load is bypassed;

The first part of switching tubes are switching tubes of an upper half bridge arm of a rectifier in the power converter, switching tubes of a lower half bridge arm of the rectifier or controllable switching tubes in a direct current conversion circuit in the power converter; the second part of switching tubes are switching tubes of an upper half bridge arm of a rectifier in the power converter, switching tubes of a lower half bridge arm of the rectifier or controllable switching tubes in a direct current conversion circuit in the power converter; when the power converter comprises a direct current conversion circuit, the direct current conversion circuit is connected to the output end of the rectifier.

The protection method for controlling the start-up of the receiving terminal is first described below.

Referring to fig. 28, a flowchart of a protection method for a wireless charging receiving end during power-on is provided in an embodiment of the present application.

And S2801, when the receiving end is started, controlling the normally closed relay to be closed, and controlling the switching tube in the power converter to be closed so as to bypass the load.

The purpose of the bypass load is to prevent current from flowing through the load, so that even if the load is disconnected, the two ends of the load cannot have excessively high voltage when the transmitting end is started, and the load is further protected from being damaged when the transmitting end is started.

And 2802, when the current of the transmitting coil of the transmitting end is determined to be larger than the first preset current, controlling the rectifier to work normally.

The rectifier is controlled to work normally, namely the rectifier starts to work in a rectifying mode, at the moment, the transmitting end transmits power normally, and the rectifier rectifies alternating current into direct current to charge a load.

The protection method for controlling the receiving end to be turned off is described below.

Referring to fig. 29, a flowchart of a protection method when a wireless charging receiving end is turned off is provided in an embodiment of the present application.

And S2901, when the receiving end is shut down, a switching tube in the power converter is controlled to be closed, and then the normally closed relay is controlled to be closed, so that the load is bypassed.

The purpose of the bypass load is to prevent current from flowing through the load, so that even if the load is disconnected, the two ends of the load cannot have excessive voltage when the transmitting end is powered off, and the load is further protected from being damaged when the transmitting end is powered on.

S2902, when the current of the transmitting coil of the transmitting end is determined to be smaller than the second preset current and larger than the first preset current, the receiving end is controlled to enter a power-off state.

Because the wireless charging receiving terminal can have different implementation manners, corresponding specific power-on and power-off processes are different, and are described below.

First kind:

the receiving end further comprises: a first field effect transistor and a second field effect transistor.

The first field effect tube and the second field effect tube are connected in parallel at two ends of the normally-closed relay after being connected in reverse series.

At this time, when the receiving end is started up, the method further includes:

the normally-closed relay is controlled to be disconnected firstly, and then the first field effect transistor and the second field effect transistor are controlled to be disconnected.

When the receiving end is powered off, the method further comprises the following steps:

and before the normally-closed relay is controlled to be closed, the first field effect transistor and the second field effect transistor are controlled to be closed.

Second kind:

the receiving end also comprises a bidirectional controllable switch connected in parallel with the two ends of the normally closed relay.

the normally-closed relay is controlled to be disconnected firstly, and then the bidirectional controllable switch is controlled to be disconnected.

and before the normally-closed relay is controlled to be closed, the bidirectional controllable switch is controlled to be closed.

In practical applications, the power converter at the receiving end may also have other different implementation manners, and specific corresponding power-on and power-off processes are different, and are described below. It is understood that for various implementations of the power converter, both implementations may be collocated.

First kind:

the power converter comprises a rectifier, wherein the rectifier comprises two bridge arms, and switching tubes of an upper half bridge arm and a lower half bridge arm of the two bridge arms are controllable switching tubes.

At this time, when the receiving terminal is started, the normally closed relay is controlled to be closed, the switching tube in the power converter is controlled to be closed so that the load is bypassed, and then the normally closed relay is controlled to be opened and the starting work of the receiving terminal is controlled, and the method specifically comprises the following steps:

when the receiving end is started, the normally closed relay is controlled to be closed, and the switching tubes of the upper half bridge arm of the rectifier are controlled to be closed or the switching tubes of the lower half bridge arm of the rectifier are controlled to be closed, so that the load is bypassed. When the current of the transmitting coil of the transmitting end is determined to be larger than a first preset current, the phase shift angle between the two bridge arms is controlled to gradually increase to a preset value, the switching tube of the upper half bridge arm and the switching tube of the lower half bridge arm are controlled to be conducted in a complementary mode, and then the receiving end is controlled to start to work.

When the receiving end is powered off, a switching tube in the power converter is controlled to be closed, then the normally closed relay is controlled to be closed, so that the load is bypassed, and then the receiving end is controlled to enter a power-off state, and the method specifically comprises the following steps:

when the receiving end is powered off, when the current of the transmitting coil of the transmitting end is determined to be smaller than the second preset current and larger than the first preset current, the phase shift angle between the two bridge arms is controlled to be gradually reduced until the switching tubes of the upper half bridge arm or the switching tubes of the lower half bridge arm of the rectifier are closed, then the normally closed relay is controlled to be closed, so that the load is bypassed, and then the receiving end is controlled to enter a power-off state.

Second kind:

the power converter comprises a rectifier, wherein the rectifier comprises two bridge arms, the switching tubes of the upper half bridge arms of the two bridge arms are diodes, and the switching tubes of the lower half bridge arms of the two bridge arms are controllable switching tubes.

When the receiving end is started, the normally closed relay is controlled to be closed, the switching tube in the power converter is controlled to be closed so that the load is bypassed, and then the normally closed relay is controlled to be opened and the starting work of the receiving end is controlled, and the method specifically comprises the following steps:

when the receiving end is started, the normally closed relay is controlled to be closed, and the controllable switch tube is controlled to be closed, so that the load is bypassed. When the current of the transmitting coil of the transmitting end is determined to be larger than a first preset current, the duty ratio of the driving signals of the controllable switching tubes of the two bridge arms is controlled to be gradually reduced to a preset value, and then the receiving end is controlled to start working.

when the receiving end is powered off, when the current of the transmitting coil of the transmitting end is determined to be smaller than the second preset current and larger than the first preset current, the duty ratio of the controllable switching tubes of the two bridge arms is controlled to be gradually increased until the controllable switching tubes are all closed, then the normally closed relay is controlled to be closed, so that the load is bypassed, and then the receiving end is controlled to enter a power-off state.

Third kind:

the power converter comprises a rectifier, wherein the rectifier comprises a bridge arm, and switching tubes of an upper half bridge arm and a lower half bridge arm of the bridge arm are controllable switching tubes.

when the receiving end is started, the normally closed relay is controlled to be closed, and the switching tube of the lower half bridge arm of the rectifier is controlled to be closed, so that the load is bypassed. When the current of the transmitting coil of the transmitting end is determined to be larger than a first preset current, the switching tube of the upper half bridge arm and the switching tube of the lower half bridge arm are controlled to be conducted in a complementary mode.

when the receiving end is shut down, when the current of the transmitting coil of the transmitting end is determined to be smaller than the second preset current and larger than the first preset current, the switching tube of the lower half bridge arm of the rectifier is controlled to be closed, the normally closed relay is controlled to be closed, so that the load is bypassed, and the receiving end is controlled to enter a shut down state.

Fourth kind:

the power converter comprises a rectifier, wherein the rectifier comprises a bridge arm, the lower half bridge arm of the bridge arm is a controllable switch tube, and the upper half bridge arm of the bridge arm is a diode.

when the receiving end is started, the normally closed relay is controlled to be closed, and the controllable switch tube of the rectifier is controlled to be closed, so that the load is bypassed. When the current of the transmitting coil of the transmitting end is determined to be larger than the first preset current, the switching state of the controllable switching tube is controlled according to the preset duty ratio.

when the receiving end is shut down, when the current of the transmitting coil of the transmitting end is determined to be smaller than the second preset current and larger than the first preset current, the controllable switch tube is controlled to be closed, the normally closed relay is controlled to be closed, so that the load is bypassed, and the receiving end is controlled to enter a shut down state.

In summary, by using the protection method for the receiving end during startup or shutdown provided by the embodiment of the application, the receiving end and the load can be protected from being damaged during startup or shutdown of the receiving end, so that the safety of the wireless charging system is improved.

System embodiment:

based on the receiving end and the protection method provided by the above embodiments, the embodiments of the present application further provide a wireless charging system, which is specifically described below with reference to the accompanying drawings.

Referring to fig. 30, a schematic diagram of a wireless charging system according to an embodiment of the present application is shown.

The wireless charging system 3000 includes: a receiving end 1000a for wireless charging and a transmitting end 1001a for wireless charging.

Wherein, the transmitting terminal 1001a of wireless charging includes at least: inverter H1, transmitting coil Lp, transmitting-side compensation network 100, and transmitting-side controller 101.

The inverter H1 inverts the direct current output from the direct current power supply into alternating current.

The compensation network 100 at the transmitting end compensates the alternating current and then transmits the alternating current to the transmitting coil Lp.

The transmitting coil Lp transmits the compensated alternating current in the form of an alternating magnetic field.

The transmitting-end controller 101 controls the closing of the controllable switching tube of the inverter H1, so that the transmitting coil Lp generates the transmitting current required by the receiving end, and is further configured to receive the power-on request or the power-off request sent by the receiving-end controller 201, or send the power-on request or the power-off request to the receiving-end controller 201.

The transmitting end controller 101 is further configured to send the current of the transmitting coil to the receiving end controller 201.

The specific description of the wireless charging receiving terminal 1000a can be referred to the above embodiments, and the present embodiment is not repeated here.

The wireless charging receiving end 1000a and the wireless charging transmitting end 1001a communicate wirelessly, thereby realizing synchronous control of shutdown and startup.

When the wireless charging receiving end 1000a is started, the controller controls the normally closed relay to be closed, and controls the switching tube of the upper half bridge arm or the switching tube of the lower half bridge arm of the rectifier to be closed, so that the load is bypassed, no current flows through the load, and therefore, the two ends of the load cannot have excessive voltage when the transmitting end is started, and the load is further protected from damage. The controller then controls the normally closed relay to be disconnected, and the receiving end starts to work for wireless charging.

When the wireless charging receiving end 1000a is powered off, the controller controls the switching tube of the upper half bridge arm or the switching tube of the lower half bridge arm of the rectifier to be closed, the normally closed relay is closed, so that the load is bypassed, no current flows through the load, and then the controller controls the receiving end to enter a power-off state. Therefore, the two ends of the load cannot have excessive voltage when the transmitting end is powered off, and the load is further protected from being damaged when the transmitting end is powered off. In addition, when the load is bypassed, the other half bridge arm of the rectifier is bypassed, so that no current flows through the other half bridge arm of the rectifier, and the two ends of the other half bridge arm cannot have excessive voltage when the transmitting end is started or shut down, so that the rectifier is protected, namely the receiving end is protected.

In summary, since the receiving end performs the protection measures during the startup and shutdown, when the input end of the power converter of the receiving end is a current source, the load is ensured not to be opened, thereby protecting the receiving end from being exploded, and further improving the safety of the wireless charging system.

It should be understood that in the present application, "at least one (item)" means one or more, and "a plurality" means two or more. "and/or" for describing the association relationship of the association object, the representation may have three relationships, for example, "a and/or B" may represent: only a, only B and both a and B are present, wherein a, B may be singular or plural. The character "/" generally indicates that the context-dependent object is an "or" relationship. "at least one of" or the like means any combination of these items, including any combination of single item(s) or plural items(s). For example, at least one (one) of a, b or c may represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", wherein a, b, c may be single or plural.

The above description is only of the preferred embodiment of the present application, and is not intended to limit the present application in any way. While the application has been described with reference to preferred embodiments, it is not intended to be limiting. Any person skilled in the art can make many possible variations and modifications to the technical solution of the present application or modifications to equivalent embodiments using the methods and technical contents disclosed above, without departing from the scope of the technical solution of the present application. Therefore, any simple modification, equivalent variation and modification of the above embodiments according to the technical substance of the present application still fall within the scope of the technical solution of the present application.

Claims

1. A receiving terminal for wireless charging, comprising: the power converter comprises a receiving coil, a compensation network, a power converter, a normally closed relay and a controller;

the receiving coil is used for converting the alternating magnetic field emitted by the emitting end into alternating current and transmitting the alternating current to the compensation network;

the compensation network is used for compensating the alternating current and then transmitting the alternating current to the rectifier;

the normally closed relay is connected in parallel with the output end of the compensation network;

the power converter is used for rectifying the compensated alternating current into direct current and providing the direct current to a load;

the compensation network is a compensation circuit with a current source characteristic, so that the receiving coil and the compensation network make the input end of the rectifier a constant current source under the combined action of the transmitting end;

the controller is used for controlling the normally closed relay to be closed when the receiving end is started, by controlling the switching tube in the power converter to be closed so that the load is bypassed, and then controlling the normally closed relay to be opened and controlling the receiving end to start working; or when the receiving end is shut down, the switching tube in the power converter is controlled to be closed, and then the normally closed relay is controlled to be closed, so that the load is bypassed, and then the receiving end is controlled to enter a shut down state.

2. The receiving terminal according to claim 1, wherein the controller is specifically configured to control the normally closed relay to be closed when the receiving terminal is turned on, and to cause the load to be bypassed by controlling a first portion of the switching tubes in the power converter to be closed when the receiving terminal is turned on; when the receiving end is shut down, the second part of switching tube in the power converter is controlled to be closed, and then the normally closed relay is controlled to be closed, so that the load is bypassed;

3. The receiving end of claim 1, further comprising: a first field effect transistor and a second field effect transistor;

The first field effect tube and the second field effect tube are connected in series in an opposite direction and then connected in parallel to the two ends of the normally-closed relay;

the controller is used for controlling the normally-closed relay to be disconnected when the receiving end is started, and then controlling the first field effect transistor and the second field effect transistor to be disconnected; when the receiving end is shut down, the first field effect tube and the second field effect tube are controlled to be closed, and then the normally closed relay is controlled to be closed.

4. The receiving end of claim 1, further comprising: a bidirectional controllable switch;

the two-way controllable switch is connected in parallel with two ends of the normally closed relay;

the controller is used for controlling the normally closed relay to be disconnected when the receiving end is started, and then controlling the bidirectional controllable switch to be disconnected; when the receiving end is powered off, the bidirectional controllable switch is controlled to be closed, and then the normally closed relay is controlled to be closed.

5. The receiving end according to any one of claims 2-4, wherein the rectifier comprises two bridge arms, and the switching tubes of the upper half bridge arm and the lower half bridge arm of the two bridge arms are controllable switching tubes;

when the receiving end is started, the controller controls the normally closed relay to be closed, and controls the switching tubes of the upper half bridge arm or the switching tubes of the lower half bridge arm of the rectifier to be closed so that the load is bypassed; when the current of the transmitting coil of the transmitting end is determined to be larger than a first preset current, controlling the phase shift angle between the two bridge arms to gradually increase to a preset value, controlling the switching tube of the upper half bridge arm and the switching tube of the lower half bridge arm to conduct complementarily, and controlling the receiving end to start working.

6. The receiving terminal according to claim 5, wherein when the receiving terminal is turned off, the controller controls the phase shift angle between the two bridge arms to gradually decrease until the switching tubes of the upper half bridge arm or the switching tubes of the lower half bridge arm of the rectifier are closed, and then controls the normally closed relay to be closed, so that the load is bypassed, and then controls the receiving terminal to enter a turned-off state when it is determined that the current of the transmitting coil of the transmitting terminal is smaller than a second preset current and larger than the first preset current.

7. The receiving end according to any one of claims 2-4, wherein the rectifier comprises two bridge arms, the switching tubes of the upper half bridge arms of the two bridge arms are diodes, and the switching tubes of the lower half bridge arms of the two bridge arms are controllable switching tubes;

when the receiving end is started, the controller controls the normally closed relay to be closed, controls the controllable switching tubes to be closed so that the load is bypassed, and controls the duty ratio of driving signals of the controllable switching tubes of the two bridge arms to be gradually reduced to a preset value when the current of the transmitting coil of the transmitting end is determined to be larger than a first preset current, and then controls the receiving end to start working.

8. The receiving terminal of claim 7, wherein when the receiving terminal is turned off, and when it is determined that the current of the transmitting coil of the transmitting terminal is smaller than a second preset current and larger than the first preset current, the controller controls the duty ratio of the controllable switching tubes of the two bridge arms to gradually increase until the controllable switching tubes are all closed, then controls the normally closed relay to be closed, so that the load is bypassed, and then controls the receiving terminal to enter a turned-off state.

9. The receiving end according to any one of claims 2-4, wherein the rectifier comprises a bridge arm, and the switching tubes of the upper half bridge arm and the lower half bridge arm of the bridge arm are controllable switching tubes;

when the receiving end is started, the controller controls the normally closed relay to be closed, controls the switching tube of the lower half bridge arm of the rectifier to be closed so that the load is bypassed, and controls the switching tube of the upper half bridge arm and the switching tube of the lower half bridge arm to be complementarily conducted when the current of the transmitting coil of the transmitting end is determined to be larger than a first preset current.

10. The receiving terminal of claim 9, wherein when the receiving terminal is turned off, the controller controls the switching tube of the lower half bridge arm of the rectifier to be closed, and controls the normally closed relay to be closed, so that the load is bypassed, and controls the receiving terminal to enter a turned-off state when it is determined that the current of the transmitting coil of the transmitting terminal is smaller than a second preset current and larger than the first preset current.

11. The receiving end according to any one of claims 2-4, wherein the rectifier comprises a bridge arm, a lower half bridge arm of the bridge arm being a controllable switching tube, an upper half bridge arm of the bridge arm being a diode;

when the receiving end is started, the controller controls the normally closed relay to be closed, controls the controllable switching tube of the rectifier to be closed so that the load is bypassed, and controls the switching state of the controllable switching tube with a preset duty ratio when the current of the transmitting coil of the transmitting end is determined to be larger than a first preset current.

12. The receiver of claim 11, wherein when the receiver is turned off, the controller controls the controllable switching tube to close and controls the normally closed relay to close so that the load is bypassed and controls the receiver to enter a turned-off state when it is determined that the current of the transmitting coil of the transmitting terminal is smaller than a second preset current and larger than the first preset current.

13. The receiving end according to any of claims 2-4, characterized in that when the power converter comprises a rectifier and a dc conversion circuit, the rectifier comprises only diodes, the dc conversion circuit comprises controllable switching tubes.

14. The wireless charging protection method is characterized by being applied to a wireless charging receiving end; the receiving end comprises: the power converter comprises a receiving coil, a compensation network, a power converter and a normally closed relay; the compensation network is a compensation circuit with a current source characteristic, so that the receiving coil and the compensation network make the input end of the rectifier be a constant current source under the combined action of the transmitting end;

the method comprises the following steps:

when the receiving end is started, the normally closed relay is controlled to be closed, a load is bypassed by controlling a switching tube in the power converter to be closed, and then the normally closed relay is controlled to be opened and the receiving end is controlled to start working;

or alternatively, the first and second heat exchangers may be,

when the receiving end is powered off, the switching tube in the power converter is controlled to be closed, the normally closed relay is controlled to be closed, so that the load is bypassed, and the receiving end is controlled to enter a power-off state.

15. The protection method according to claim 14, wherein when the receiving end is turned on, the normally closed relay is controlled to be closed, and the specified switching tube in the power converter is controlled to be closed, so that the load is bypassed, specifically comprising:

when the receiving end is shut down, the normally closed relay is controlled to be closed by controlling a specified switching tube in the power converter to be closed, so that the load is bypassed, and the method specifically comprises the following steps:

16. The protection method according to claim 14, wherein the receiving end further comprises: a first field effect transistor and a second field effect transistor; the first field effect tube and the second field effect tube are connected in series in an opposite direction and then connected in parallel to the two ends of the normally-closed relay;

When the receiving end is started, the method further comprises the following steps:

before the first field effect transistor and the second field effect transistor are disconnected, the normally-closed relay is controlled to be disconnected;

17. The protection method according to claim 14, wherein the receiving end further comprises: the two-way controllable switch is connected in parallel with two ends of the normally closed relay;

when the receiving end is started up, the method further comprises the following steps:

before the bidirectional controllable switch is controlled, the normally-closed relay is controlled to be disconnected;

and before the normally closed relay is controlled to be closed, the bidirectional controllable switch is controlled to be closed.

18. The protection method according to any one of claims 15-17, wherein the power converter comprises a rectifier, the rectifier comprises two bridge arms, and switching tubes of an upper half bridge arm and a lower half bridge arm of the two bridge arms are controllable switching tubes;

when the receiving end is started, the normally closed relay is controlled to be closed, the switching tube in the power converter is controlled to be closed so that the load is bypassed, and then the normally closed relay is controlled to be opened and the receiving end is controlled to start working, and the method specifically comprises the following steps:

When the receiving end is started, the normally closed relay is controlled to be closed, and the switching tubes of the upper half bridge arm or the switching tubes of the lower half bridge arm of the rectifier are controlled to be closed so that the load is bypassed; when the current of the transmitting coil of the transmitting end is determined to be larger than a first preset current, controlling the phase shift angle between the two bridge arms to gradually increase to a preset value, controlling the switching tube of the upper half bridge arm and the switching tube of the lower half bridge arm to conduct complementarily, and controlling the receiving end to start working.

19. The protection method according to claim 18, wherein when the receiving terminal is turned off, controlling the switching tube in the power converter to be closed and controlling the normally closed relay to be closed so that the load is bypassed and controlling the receiving terminal to enter a turned-off state comprises:

when the receiving end is powered off, when the current of the transmitting coil of the transmitting end is determined to be smaller than a second preset current and larger than the first preset current, the phase shifting angle between the two bridge arms is controlled to be gradually reduced until the switching tubes of the upper half bridge arm or the switching tubes of the lower half bridge arm of the rectifier are closed, then the normally closed relay is controlled to be closed, so that the load is bypassed, and then the receiving end is controlled to enter a powered off state.

20. The protection method according to any one of claims 15-17, wherein the power converter comprises a rectifier, the rectifier comprises two bridge arms, switching tubes of an upper half bridge arm of the two bridge arms are diodes, and switching tubes of a lower half bridge arm of the two bridge arms are controllable switching tubes;

when the receiving end is started, the normally closed relay is controlled to be closed, and the controllable switch tubes are controlled to be closed so that the load is bypassed; when the current of the transmitting coil of the transmitting end is determined to be larger than a first preset current, the duty ratio of the driving signals of the controllable switching tubes of the two bridge arms is controlled to be gradually reduced to a preset value, and then the receiving end is controlled to start working.

21. The protection method according to claim 20, wherein when the receiving terminal is turned off, controlling the switching tube in the power converter to be closed and controlling the normally closed relay to be closed so that the load is bypassed and controlling the receiving terminal to enter a turned-off state comprises:

When the receiving end is powered off, when the current of the transmitting coil of the transmitting end is determined to be smaller than a second preset current and larger than the first preset current, the duty ratio of the controllable switching tubes of the two bridge arms is controlled to be gradually increased until the controllable switching tubes are all closed, then the normally closed relay is controlled to be closed, so that the load is bypassed, and then the receiving end is controlled to enter a powered off state.

22. The protection method according to any one of claims 15-17, wherein the power converter comprises a rectifier, the rectifier comprising a bridge arm, the switching tubes of the upper half bridge arm and the lower half bridge arm of the bridge arm being controllable switching tubes;

when the receiving end is started, the normally closed relay is controlled to be closed, and the switching tube of the lower half bridge arm of the rectifier is controlled to be closed so that the load is bypassed; and when the current of the transmitting coil of the transmitting end is determined to be larger than a first preset current, controlling the switching tube of the upper half bridge arm and the switching tube of the lower half bridge arm to be conducted complementarily.

23. The protection method according to claim 22, wherein when the receiving terminal is turned off, controlling the switching tube in the power converter to be closed and controlling the normally closed relay to be closed so that the load is bypassed and controlling the receiving terminal to enter a turned-off state comprises:

when the receiving end is powered off, when the current of the transmitting coil of the transmitting end is determined to be smaller than a second preset current and larger than the first preset current, a switching tube of a lower half bridge arm of the rectifier is controlled to be closed, then the normally closed relay is controlled to be closed, so that the load is bypassed, and then the receiving end is controlled to enter a powered off state.

24. The protection method according to any one of claims 15-17, wherein the power converter comprises a rectifier, the rectifier comprising a bridge arm, a lower half of the bridge arm being a controllable switching tube, an upper half of the bridge arm being a diode;

When the receiving end is started, the normally closed relay is controlled to be closed, and the controllable switching tube of the rectifier is controlled to be closed so that the load is bypassed; and when the current of the transmitting coil of the transmitting end is determined to be larger than a first preset current, controlling the switching state of the controllable switching tube with a preset duty ratio.

25. The protection method according to claim 24, wherein when the receiving terminal is turned off, controlling the switching tube in the power converter to be closed and controlling the normally closed relay to be closed so that the load is bypassed and controlling the receiving terminal to enter a turned-off state comprises:

when the receiving end is powered off, when the current of the transmitting coil of the transmitting end is determined to be smaller than a second preset current and larger than the first preset current, the controllable switch tube is controlled to be closed, the normally closed relay is controlled to be closed, so that the load is bypassed, and the receiving end is controlled to enter a powered off state.

26. A system for wireless charging, comprising: a transmitting end and a receiving end according to any one of claims 1-13;

the transmitting end comprises: the system comprises an inverter, a transmitting end compensation network, a transmitting coil and a transmitting end controller;

The inverter is used for inverting the direct current into alternating current and transmitting the alternating current to the transmitting end compensation network;

the transmitting end compensation network is used for compensating the alternating current and then transmitting the alternating current to the transmitting coil;

the transmitting coil is used for transmitting the compensated alternating current in the form of an alternating magnetic field;

the transmitting end controller controls the closing of a controllable switch tube of the inverter so as to enable the transmitting coil to generate transmitting current required by the receiving end; the controller is used for receiving the starting-up request or the shutdown request sent by the controller of the receiving end, or sending the starting-up request or the shutdown request to the controller of the receiving end.

27. The system of claim 26, wherein the transmitting end controller is further configured to send the current of the transmitting coil to the receiving end controller.