WO2020211056A1

WO2020211056A1 - Wireless charging transmitting device, method, and system

Info

Publication number: WO2020211056A1
Application number: PCT/CN2019/083304
Authority: WO
Inventors: 毛云鹤; 武志贤; 刘彦丁
Original assignee: 华为技术有限公司
Priority date: 2019-04-18
Filing date: 2019-04-18
Publication date: 2020-10-22
Also published as: CN112106274A

Abstract

The present application provides a wireless charging transmitting device and a wireless charging method. The transmitting device comprises one or more inverters and a transformer connected to the one or more inverters. The transformer comprises one or more primary windings and a plurality of secondary windings, a transmitting end compensation network connected to the transformer, a transmitting coil connected to the transmitting end compensation network and a transmitting end controller. Further provided is a wireless charging system. Said system is composed of the transmitting device and a corresponding receiving device. The embodiments of the present application solve the problem of system compatibility that a wireless charging system works under different coupling coefficients (that is, the charging distances and offsets are different) and different charging power requirements, whilst reducing the volume and weight of a receiving end circuit.

Description

Wireless charging transmitting device, method and system

Technical field

This application relates to the field of power electronics technology, in particular, to a wireless charging transmitter, a wireless charging method, and a wireless charging system.

Background technique

An electric vehicle is a new energy vehicle. The electric vehicle is charged through a wireless charging system. There is no charging cable and no manual operation of the charging gun is required. It can realize unattended charging and can use APP for remote operation to make the charging process. It becomes simple. Therefore, the charging method of electric equipment such as electric vehicles and drones has gradually developed from wired charging to wireless charging. Generally, the wireless charging system of an electric vehicle is composed of two separate components. One side is a power transmitting device, which is connected to the mains, and the other side is a power receiving device, which is connected to the load. There is no electrical contact between the power transmitting device and the power receiving device, and wireless energy transmission is carried out through electromagnetic induction.

The structure of the usual wireless charging system is shown in Figure 1. The transmitting end consists of a power factor correction circuit PFC, a DC conversion circuit DC-DC1, an inverter circuit DC-AC, a transmitting end compensation network CNP, and a transmitting coil Lp; the receiving end is composed of The receiving coil Ls, the receiving end compensation network CNS, the rectifier AC-DC, and the DC converter DC-DC2 are composed. The direct current converter DC-DC1 at the transmitting end and the direct current converter DC-DC2 at the receiving end may or may not exist, so they are represented by dotted lines in the figure. For low-power applications such as 7kW and below, a single-phase power supply is usually used. When the power exceeds 7kW, a three-phase power supply is usually used. Here, a single-phase power supply is used for illustration.

At present, there are different standards for the charging of electric vehicles, and different models, the different relative positions of the receiving end coils in the electric vehicles and the different relative positions of the transmitting end coils connected to the mains, different power requirements and other external parameters make the wireless charging system have many Kind of different application conditions. Taking an electric vehicle as a load device as an example, the ground clearance of the chassis is different for different models of vehicles, and the power receiving module may be installed at the front, middle or rear of the vehicle, resulting in the distance between the transmitting coil and the receiving coil Different, the coupling coefficient between the coils will change accordingly, the same transmitting and receiving coils, the coupling coefficient between the coils near the distance is large, and the long distance coupling coefficient is small. In addition, there are multiple power levels for power transmitting devices and power receiving devices. For example, the power transmitting device can provide 11kW of power, and the power receiving device on the car can receive the maximum power of 6kW. The power transmitting device is required according to the power receiving device Needs to be charged.

In summary, the wireless charging system has many operating conditions and needs to be able to work normally under different coupling coefficients and different charging powers, so high requirements are put forward for the compatibility of the charging system.

Summary of the invention

This application discloses a transmitting device, a wireless charging method and a wireless charging system for realizing wireless charging, realizing the wireless charging function, and solving the problem of compatibility of the wireless charging system, that is, in different coupling coefficients (that is, different charging distances and offsets) and The normal operation of the receiving device can be met under different charging power requirements, and the charging state can be adjusted according to the charging power requirements to achieve the purpose of compatibility with different working conditions. And because of the increased winding switchable transformer at the transmitting end, the output voltage of the wireless charging transmitter can be adjusted Therefore, the receiving end does not need to add an additional DC converter, thereby reducing the volume of the receiving end and achieving the purpose of reducing the weight of the vehicle body.

In the first aspect of the present application, a wireless charging transmitter is provided. The transmitter is connected to the mains power grid and is used to transmit an alternating current to the wireless charging receiver by means of an alternating magnetic field. The transmitter includes a Or multiple inverters, a transformer connected to the inverter, a transmitting end compensation network connected to the transformer, a transmitting coil connected to the transmitting end compensation network, and a transmitting end controller; wherein: the inverter is used for Convert the input DC power into high-frequency AC power that can be used for wireless power transmission through electromagnetic coupling. The DC power input by the inverter can be provided by a variable-amplitude DC power supply or a rectifier circuit at the front stage of the inverter. The rectifier circuit rectifies the alternating current into direct current whose amplitude can be changed within a certain range; the transformer includes one or more primary windings and multiple secondary windings, and is used to receive the alternating current output by the inverter and output the transformed voltage The transmitting end compensation network is used for compensating the transformed alternating current and sending it to the transmitting coil; the transmitting end transmitting coil is used for transmitting the high frequency alternating current through an alternating magnetic field Transmit; The transmitter controller is used to control one or more winding access circuits in the secondary winding of the transformer, wherein different secondary winding access circuits provide different transformer output voltages.

According to the first aspect, in a first possible implementation manner of the wireless charging and transmitting device, each of the multiple secondary windings of the transformer of the wireless charging and transmitting device is connected to a switch, and the transmitting end The controller connects the corresponding secondary windings to the circuit by controlling the switch. Further, the number of the secondary windings connected to the circuit is determined by the transformer output voltage calculated according to different working conditions. The specific secondary windings The number and the number of turns of each secondary winding can be designed according to different working conditions. Because the overall transformation ratio of the secondary voltage needs to cover the range of the minimum coupling coefficient to the maximum coupling coefficient, it can make the output of the receiving end from the minimum voltage to the maximum All possible voltages of the voltage, therefore, the total number of turns of the secondary winding needs to meet the corresponding primary and secondary voltage ratio to achieve the purpose of outputting alternating current of different voltages by the transformer under different working conditions.

According to the first aspect, in a second possible implementation manner of the wireless charging transmitter device, the ratio of the output voltage of the inverter to the output voltage of the transformer is equal to the total number of turns of the primary winding of the transformer The ratio of the total number of turns of the secondary winding of the transformer connected to the circuit, that is, the controller determines the transformation ratio of the primary and secondary sides of the transformer according to the output voltage of the inverter and the required transformer output voltage, that is, the Transformer secondary winding.

According to the first aspect, in a third possible implementation manner of the wireless charging transmitter device, the input voltage of the inverter is variable.

According to the first aspect, in a fourth possible implementation manner of the wireless charging transmitting device, the transformer output voltage is based on the power demand of the wireless charging receiving end and the coupling between the transmitting coil and the receiving coil of the wireless charging receiving end The coefficient is determined, and the power demand is the output power, charging current, or charging voltage of the wireless charging transmitter required by the receiving end.

According to the fourth possible implementation manner of the first aspect, in the fifth possible implementation manner of the wireless charging transmission device, the output power of the wireless charging transmission device

The transformer output voltage Vac is proportional to the output power Po of the transmitting device, and inversely proportional to the transmitting coil current I _Lp , where k represents the coupling coefficient between the transmitting coil and the receiving coil, and ω represents the inverter and the For the operating frequency of the rectifier at the receiving end, Lp represents the inductance of the transmitting coil, Ls represents the inductance of the receiving coil, I _Lp represents the current of the transmitting coil, and I _Ls represents the current of the receiving coil.

When the working frequency ω of the inverter and the rectifier, the inductance Lp of the transmitting coil, and the inductance Ls of the receiving coil are fixed, according to different wireless charging receiving end power requirements and the transmitting coil and the receiving coil of the receiving end The coupling coefficient k between the two can be used to obtain different transmitting coil currents I _Lp , and then to obtain different transformer output voltages Vac, adjust the corresponding transformer primary and secondary turns ratio, that is, adjust the number of transformer secondary windings connected to the circuit, The purpose of dynamically adapting to different working conditions can be achieved, wherein the receiving end generates the reference current I _{Lpref of the} transmitting coil Lp through the receiving end controller according to different wireless charging receiving end power requirements to control the transmitting coil current I _Lp .

According to the first aspect or the first, second, third, fourth, and fifth possible implementation manners of the first aspect, in the sixth possible implementation manner of the wireless charging transmitter, the number of primary windings of the transformer Same as the number of inverters.

According to the first aspect or the first, second, third, fourth, and fifth possible implementation manners of the first aspect, in the seventh possible implementation manner of the wireless charging and transmitting device, the wireless charging and transmitting device further includes DC blocking capacitor, the front end of the primary winding of the transformer is connected to the inverter through a DC blocking capacitor. In this implementation, the function of the DC blocking capacitor is to avoid saturation of the transformer due to a DC voltage bias in the transformer winding.

According to the first aspect or the first, second, third, fourth, and fifth possible implementation manners of the first aspect, in an eighth possible implementation manner of the wireless charging and transmitting device, the transformer is an isolation transformer, so The primary winding and the secondary winding of the isolation transformer are electrically isolated, or the transformer is a non-isolation transformer, and the primary and secondary sides of the non-isolation transformer share partial windings.

A second aspect of the present application provides a wireless charging method that is applied to the transmitting device described in the first aspect; the method includes: controlling one or more windings in the secondary winding of the transformer Access circuits, where different secondary winding access circuits provide different transformer output voltages.

According to the second aspect, in the first possible implementation of the wireless charging method, the wireless charging method further includes: according to the power demand of the wireless charging receiving end and the transmitting coil and the receiving coil of the wireless charging receiving end The coupling coefficient of determines the output voltage of the transformer, and the power demand is the output power or the charging current or the charging voltage of the wireless charging transmitter required by the receiving end.

According to the second aspect, in the second possible implementation manner of the wireless charging method, the output power of the wireless charging transmitting device applied by the wireless charging method is

According to the second aspect, in a third possible implementation of the wireless charging method, the wireless charging method further includes: receiving a load charging instruction, wherein the load charging instruction carries the power demand of the wireless charging receiving end .

A third aspect of the present application provides a wireless charging system. The wireless charging system includes the wireless charging transmitting device and the wireless charging receiving device described in the first aspect, wherein the wireless charging receiving device is installed in an electric vehicle, etc. and needs to be charged. Inside the device, connected to the rechargeable battery;

The wireless charging receiving device includes: a receiving coil, a receiving end compensation network connected to the receiving coil, and a rectifier connected to the receiving end compensation network; wherein the receiving coil is used to receive an alternating magnetic field and output alternating current The receiving end compensation network is used for compensating the alternating current output from the receiving coil and outputting it to the rectifier, so that the equivalent input impedance of the rectifier meets the power transmission and soft switching requirements of the receiving end circuit to achieve The received AC power factor compensation improves the energy transmission efficiency of the receiving end circuit; the rectifier is used to convert the high frequency AC power received by the receiving coil into DC power that can charge the battery.

According to the third aspect, in the first possible implementation manner of the wireless charging system, the wireless charging system further includes the receiving end controller, configured to send a load charging instruction to the transmitting end controller, wherein The load charging instruction carries the power demand of the wireless charging receiving end. This implementation mode enables the transmitting end to comprehensively calculate the required power requirement based on the wireless charging receiving end power demand received from the receiving end controller and the coupling coefficient between the transmitting coil and the receiving coil. Transformer output voltage.

The transformer in the wireless charging system described in the present application enables the wireless charging system to adjust the output voltage of the corresponding transformer according to different coupling coefficients between the transmitting coil and the receiving coil and different wireless charging receiving end power requirements, which effectively solves the problem. Compatibility issues of the wireless charging system under different working conditions in the actual charging process. At the same time, compared with the prior art, the receiving device corresponding to the transmitting device containing the transformer does not require additional additions except the receiving coil, compensation network and rectifier The DC converter can adjust the voltage, so the volume of the receiving end and the weight of the vehicle body can be reduced.

In a fourth aspect of the present application, a readable storage medium is provided. The readable storage medium includes program instructions that, when run on a processor, implement the wireless charging method described in the second aspect.

Description of the drawings

The following introduces the drawings used in the embodiments of the present application.

Figure 1 is a schematic structural diagram of a commonly used wireless charging system in the prior art;

Figure 2 is a schematic diagram of a wireless charging system provided by the present application;

FIG. 3 is a schematic diagram of a transmitting device and a receiving device of a wireless charging system provided by the present application;

4 is a schematic structural diagram of a wireless charging system provided by an embodiment of the present application;

FIG. 5 is a schematic diagram of a wireless charging method provided by an embodiment of the present application;

6 is a schematic structural diagram of a wireless charging system using an isolation transformer provided by an embodiment of the present application;

FIG. 7 is a schematic diagram of control of a wireless charging system provided by an embodiment of the present application;

8 is a schematic diagram of a circuit structure of a wireless charging system using an isolation transformer provided by an embodiment of the present application;

FIG. 9 is a schematic diagram of two LCC compensation networks provided by an embodiment of the present application;

10 is a schematic diagram of the relationship between the switching tube drive signal and the phase shift angle of an inverter provided by an embodiment of the present application;

11 is a schematic diagram of the relationship between the switching tube driving signal and the phase shift angle of a rectifier provided by an embodiment of the present application;

12 is a diagram of the voltage range that can be covered when a transformer is connected to different numbers of secondary windings according to an embodiment of the present application;

13A is a schematic structural diagram of a wireless charging system in which the primary and secondary sides of an autotransformer share one winding according to an embodiment of the present application;

13B is a schematic structural diagram of a wireless charging system in which the primary and secondary sides of an autotransformer share two windings according to an embodiment of the present application;

14 is a schematic diagram of a circuit structure of a wireless charging system with a non-isolated transformer used in an embodiment of the present application;

15 is a schematic diagram of the circuit structure of another wireless charging system of an isolation transformer adopted in an embodiment of the present application;

16 is a schematic diagram of the circuit structure of a wireless charging system with two non-isolated transformers sharing windings used in an embodiment of the present application;

detailed description

The embodiments of the present application will be described below in conjunction with the drawings. 2 is a schematic diagram of a wireless charging system provided by an embodiment of the present application. The wireless charging system includes: an electric vehicle 200 and a wireless charging station 201. The electric vehicle 200 may include a wireless charging receiving device 2000, and the wireless charging station 201 may include a wireless charging transmitting device 2010. At present, the charging process of the electric vehicle by the wireless charging system is performed by the wireless charging receiving device 2000 located in the electric vehicle 200 and the wireless charging transmitting device 2010 located in the wireless charging station 201 to perform non-contact charging. The function of the wireless charging transmitting device 2010 in the charging station 201 is to send AC power to the wireless charging receiving device 2000 in the electric vehicle 200, and the wireless charging receiving device 2000 in the electric vehicle 200 is to receive wireless charging from the wireless charging station 201. The electric energy transmitted by the charging transmitter 2010 is stored in the battery of the electric vehicle to complete the charging of the electric vehicle.

Further, the electric vehicle 200 may be a hybrid vehicle or a pure electric vehicle; the wireless charging station 201 may specifically be a fixed wireless charging station, a fixed wireless charging parking space, a wireless charging road, and the wireless charging transmitter 2010 may be set on the ground The electric vehicle 200 located above it can be wirelessly charged if it is on or buried under the ground (Figure 2 shows the situation where the wireless charging transmitter 2010 is buried under the ground). The wireless charging receiving device 2000 can be specifically integrated into the bottom of the electric car 200 or other parts of the car. When the electric car 200 enters the wireless charging range of the wireless charging transmitter 2010, the electric car 200 can be charged in a wireless charging manner. The wireless charging and transmitting device 2010 can also be integrated and separate. The integrated method refers to the integration of the control circuit and the transmitting coil, and the separate method refers to the separation of the transmitting coil and the control circuit, and the power receiving antenna of the receiving device 2000 and The rectifier circuit can be integrated or separated, and the rectifier module is usually placed in the car when it is separated.

Optionally, the non-contact charging may be wireless energy transmission by the wireless charging receiving device 2000 and the wireless charging transmitting device 2010 through an electric or magnetic field coupling method, and specifically may be electric field induction, magnetic induction, magnetic resonance or wireless radiation. There are no specific restrictions. Further, the electric vehicle 200 and the wireless charging station 201 can also be charged in two directions, that is, the wireless charging station 201 charges the electric vehicle 200 through the power supply, or the electric vehicle 200 discharges to the power supply.

Figure 3 shows a schematic structural diagram of a wireless charging system. The wireless charging system consists of a transmitting device and a receiving device. Fig. 3 (left) shows a schematic structural diagram of a wireless charging transmitter 301 in a wireless charging station. The wireless charging and transmitting device 301 includes: an external power supply, a transmission conversion module, a power transmission antenna, a transmission control module connected to the transmission conversion module and the power transmission antenna, a transmission communication module connected to the transmission control module, and a transmission communication module connected to the transmission communication module. The authentication management module, and the storage module connected with the authentication management module.

The emission conversion module can be connected to the power source to obtain energy from the power source and convert the AC or DC power supply of the power source into high-frequency AC power. When the power supply is AC input, the transmission conversion module is composed of a power factor correction unit (not shown in Figure 3) and an inverter unit (not shown in Figure 3). The power factor correction unit can convert 220V industrial frequency AC power into DC power; When the power supply is direct current input, the transmission conversion module is composed of an inverter unit (not shown in Figure 3). The power factor correction unit can ensure that the phase of the input current of the wireless charging system is consistent with the phase of the grid voltage, reduce the harmonic content of the system, and increase the power factor value to reduce the pollution of the wireless charging system to the grid and improve the efficiency and reliability of transmission. The power factor correction unit can also increase or decrease the output voltage of the power factor correction unit according to the requirements of the subsequent stage to meet the required voltage requirements. The inverter unit can convert the voltage output by the power factor correction unit into a high-frequency AC voltage and act on the power transmitting antenna. The high-frequency AC voltage can greatly improve the transmission efficiency and transmission distance. It should be noted that the power supply may be a power supply inside the wireless charging transmission system, or an external power supply external to the wireless charging transmission system, which is not specifically limited in this application.

The transmission control module is used to control the parameter adjustment of the voltage, current and frequency conversion of the transmission conversion circuit according to the actual wireless charging transmission power requirements, and control the voltage and current output adjustments of the high-frequency alternating current in the power transmission antenna, according to different working conditions , That is, with different coupling coefficients of the transmitting coil and receiving coil, and different receiving end power requirements, the transmitting control module can effectively adjust the electrical parameters of the transmitting coil to cope with different working conditions.

The power transmitting antenna uses the principle of electromagnetic induction to transmit alternating current to the receiving antenna in the form of an alternating magnetic field in the inductively coupled energy transmission mode. In the resonantly coupled energy transmission mode, it passes through a network composed of inductors and capacitors. The high-frequency alternating current is converted into resonant alternating current, and the resonant alternating current is transmitted to the receiving end coil in an alternating magnetic field. In addition, in order to realize the two-way charging function of the wireless charging system, the wireless charging transmitting device in the wireless charging system may also include a power receiving antenna, which may be a stand-alone type or an integrated type.

The transmitting communication module is used for wireless communication between the wireless charging transmitter and the wireless charging receiving device, including power control information, fault protection information, switch machine information, interactive authentication information, etc. On the one hand, the wireless charging transmitter device can receive the attribute information, charging request, power control information, and mutual authentication information of the electric vehicle sent by the wireless charging receiver device; on the other hand, the wireless charging transmitter device can also send wireless charging to the wireless charging device. Charging transmission control information, interactive authentication information, wireless charging history data information, etc. Specifically, the aforementioned wireless communication methods may include, but are not limited to, Bluetooth (bluetooth), wireless broadband (WIreless-Fidelity, WiFi), Zigbee protocol (Zigbee), radio frequency identification technology (RFID), remote (Long Range). , Lora) wireless technology, near field communication technology (Near Field Communication, NFC) any one or a combination of multiple. Further, the transmitting communication module can also communicate with the smart terminal of the user of the electric vehicle, and the user can realize remote authentication and user information transmission through the communication function.

The authentication management module is used for the interactive authentication and authority management of the wireless charging transmitter and the electric vehicle in the wireless charging system. The processor in this module can process the interactive authentication and authority management information, and control the transmitting end to receive authentication and authority approval Turn on the wireless charging function at the end.

The storage module is used to store the charging process data, interactive authentication data (such as interactive authentication information) and authority management data (such as authority management information) of the wireless charging transmitter. Among them, the interactive authentication data and authority management data can be factory settings or It is set by the user, which is not specifically limited in the embodiment of this application.

Fig. 3 (right) shows a schematic structural diagram of a wireless charging receiving device 302 in an electric vehicle. The wireless charging receiving device includes: a power receiving antenna, a receiving control module connected with the power receiving antenna, a receiving conversion module connected with the receiving control module, and a receiving communication module. Further, the receiving conversion module can be connected with the energy storage management module and the energy storage module to give control to the energy storage management module, and use the energy received by the receiving conversion module to charge the energy storage module and further use it for driving electric vehicles . It should be noted that the energy storage management module and the energy storage module may be located inside the wireless charging receiving device or outside the wireless charging receiving device, which is not specifically limited in the embodiment of the present application.

The power receiving antenna, in the inductive coupling energy transmission mode or the resonance coupling energy transmission mode, is used to directly use the principle of electromagnetic induction to receive the alternating magnetic field from the power transmitting antenna and output alternating current. In addition, in order to realize the two-way charging function of the wireless charging system, the wireless charging receiving device in the wireless charging system may also include a power transmitting antenna, which may be a stand-alone type or an integrated type.

The receiving control module is used to control the voltage, current and frequency conversion parameter adjustment of the receiving conversion module according to the actual wireless charging receiving power demand.

The receiving conversion module is used to convert the high-frequency current and voltage or high-frequency resonance current and voltage received by the power receiving antenna into the DC voltage and DC current required for charging the energy storage module. The receiving conversion module is usually composed of a rectifier unit (not shown in Figure 3) and a DC conversion unit (not shown in Figure 3); the rectifier unit receives the high-frequency current and voltage or high-frequency resonance current and voltage received by the antenna. Converted into DC voltage and DC current, the DC conversion unit provides a stable DC voltage for the subsequent charging circuit to realize constant mode charging.

The receiving communication module is used for wireless communication between the wireless charging transmitter and the wireless charging receiving device. Including power control information, fault protection information, switch machine information, interactive authentication information, etc. On the one hand, the wireless charging receiving device can send attribute information, charging request, power control information, and interactive authentication information of the electric vehicle to the wireless charging transmitting device; on the other hand, the wireless charging receiving device can also receive the transmission sent by the wireless charging transmitting device Control information, interactive authentication information, wireless charging history data information, etc. Specifically, the aforementioned wireless communication methods may include, but are not limited to, Bluetooth (bluetooth), wireless broadband (WIreless-Fidelity, WiFi), Zigbee protocol (Zigbee), radio frequency identification technology (RFID), remote (Long Range). , Lora) wireless technology, near field communication technology (Near Field Communication, NFC) any one or a combination of multiple. Further, the receiving communication module can also communicate with the smart terminal of the user of the electric vehicle. The user can realize remote authentication and user information transmission through the communication function, and the smart terminal controls the vehicle and the transmitter for wireless charging interaction.

Based on the above-mentioned wireless charging station, this application proposes a new transmitter device with a winding switchable transformer. The transmitter device with a winding switchable transformer can solve the compatibility problem of the wireless charging system, that is, in different coupling coefficients (ie charging distance Different from the offset) and different charging powers, it can meet the normal operation of the receiving end device, and can adjust the charging state according to the charging requirements to achieve the purpose of compatibility. And because the winding switchable transformer added at the transmitting end can adjust the output voltage, The receiving end does not require an additional DC converter, which can reduce the volume of the receiving end and achieve the purpose of reducing the weight of the vehicle body.

In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present application will be described clearly and completely in conjunction with the accompanying drawings in the embodiments of the present application.

Please refer to FIG. 4, which is a schematic structural diagram of a wireless charging system provided by an embodiment of the present application. The wireless charging system includes a transmitting device connected to a DC power supply or an AC power supply, and is installed in an electric vehicle, and the electric vehicle The receiving device connected to the energy storage battery. The transmitter includes an inverter 401, a transformer 402, a transmitter compensation network 403, a transmitter coil 404, and a transmitter controller 408. The wireless charging transmitter provided in this embodiment of the application can be installed in parking lots, private parking spaces, charging In various scenes such as station platforms. The receiving device includes a receiving coil 405, a receiving end compensation network 406, a rectifier 407, and a receiving end controller 409. The wireless charging receiving device provided in the embodiment of the present application can be installed in electric vehicles, hybrid vehicles, drones, etc., where charging is required. Inside the device, it is connected to a rechargeable battery.

The inverter 401 is used to convert direct current to alternating current, for example, to convert direct current with variable voltage output from a direct current power supply or a direct current formed by rectification of industrial frequency alternating current mains power into high frequency that can be used for wireless power transmission through electromagnetic induction. Alternating current. The transformer 402 includes one or more primary windings and multiple secondary windings, and is used to receive the alternating current output by the inverter and output the transformed alternating current. The transmitting end compensation network 403 is used to compensate the transformed alternating current and send it to the transmitting coil. The compensation network 403 enables the output equivalent impedance of the inverter to meet the power transmission and soft switching requirements of the transmitting end circuit to realize power factor compensation and improve the energy transmission efficiency of the transmitting end circuit. The transmitting coil 404 is used to transmit alternating current through an alternating magnetic field; the transmitting end controller 408 is used to control one or more windings in the secondary winding of the transformer to be connected to the circuit, where different The secondary winding access circuit provides different transformer output voltages.

Each of the multiple secondary windings of the transformer 402 is connected to a switch, and the transmitter controller connects the corresponding secondary winding to the circuit by controlling the switch. The switch can be a mechanical switch, an electrical switch, or a relay, etc., as long as it is a controllable switch, which is not limited in this application. Further, the number of access circuits of the secondary winding is determined by the output voltage of the transformer calculated according to different working conditions. The specific number of secondary windings and the number of turns of each secondary winding can be determined according to different working conditions. Design, because the overall transformation ratio of the secondary side voltage needs to cover all possible voltages from the minimum voltage output by the receiving end to the maximum voltage from the minimum coupling coefficient to the maximum coupling coefficient, therefore, the total number of turns of the secondary winding needs to meet the corresponding The primary and secondary voltage ratio of the transformer, so as to achieve the purpose of outputting alternating current with different voltages under different working conditions.

In an implementation manner, the input voltage of the inverter of the wireless charging transmitter device is variable. The ratio of the output voltage of the inverter 401 to the output voltage of the transformer 402 is equal to the ratio of the total number of turns of the primary winding of the transformer to the total number of turns of the secondary winding of the transformer connected to the circuit. The controller determines the transformation ratio of the primary and secondary sides of the transformer according to the output voltage of the inverter and the required output voltage of the transformer, that is, determines the secondary winding of the transformer to be connected to the circuit. The output voltage of the transformer 402 is determined by the power demand of the wireless charging receiving end and the coupling coefficient between the transmitting coil and the receiving coil of the wireless charging receiving end, and the power demand is the wireless charging transmitting device required by the receiving end The size of the output power or the size of the charging current or the size of the charging voltage.

The output power of the wireless charging transmitter

When the working frequency ω of the inverter and the rectifier, the inductance Lp of the transmitting coil, and the inductance Ls of the receiving coil are fixed, according to different wireless charging receiving end power requirements and the transmitting coil and the receiving coil of the receiving end The coupling coefficient k between the two can be used to obtain different transmitting coil currents I _Lp , and then to obtain different transformer output voltages Vac, and adjust the corresponding transformer primary and secondary turns ratio, that is, adjust the number of transformer secondary windings connected to the circuit, It can achieve the purpose of dynamically adapting to different working conditions. In some embodiments, the wireless charging transmitter device further includes a DC blocking capacitor, the front end of the transformer primary winding is connected to the inverter through a DC blocking capacitor, and the function of the DC blocking capacitor is to avoid a DC voltage deviation in the transformer winding. Setting causes the transformer to saturate.

In some embodiments, the transformer may be an isolation transformer, and the primary winding and the secondary winding of the isolation transformer are electrically isolated, or the transformer may be a non-isolation transformer, and the primary side of the non-isolation transformer It shares some windings with the secondary side.

The receiving coil 405 is used for receiving the alternating magnetic field sent by the transmitting coil and outputting alternating current; the receiving end compensation network 406 is used for compensating the alternating current output by the receiving coil and outputting it to the rectifier so that the rectifier The input equivalent impedance meets the requirements of the power transmission and soft switching of the receiving end circuit to realize the compensation of the received AC power factor and improve the energy transmission efficiency of the receiving end circuit; the rectifier 407 is used to transfer the high voltage received by the receiving coil Frequency AC power is converted into DC power that can charge the battery.

The wireless charging system further includes the receiving end controller 409, configured to send a load charging instruction to the transmitting end controller, wherein the load charging instruction carries the power demand of the wireless charging receiving end, so that the transmitting end is based on The required transformer output voltage is obtained by comprehensive calculation from the power demand of the wireless charging receiving end received by the receiving end controller and the coupling coefficient between the transmitting coil and the receiving coil.

In the above embodiment, the secondary winding of the transformer at the transmitting end can be adjusted. In addition to solving the compatibility problem of the wireless charging system under different working conditions in the actual charging process, the design of the transformer can also eliminate the need for a wireless charging system receiving device. The commonly used DC-DC converter can reduce the high-frequency noise generated during the switching process of the DC-DC converter, which is beneficial to the EMC and EMI design of the wireless charging system. In addition, the receiving device only has a coil, a compensation network and a rectifier, and does not require a DC conversion circuit, which can ensure that the volume and weight of the receiving device are as small as possible, and meet the requirements of electric vehicles, unmanned aerial vehicles, and the like.

FIG. 5 is a schematic flowchart of a wireless charging method provided by an embodiment of the present application. The process may be implemented based on the wireless charging system shown in FIG. 4, and the method includes the following steps:

Step S501: The transmitter controller detects the coupling coefficient K of the transmitter coil and the receiver coil;

Step S502: The transmitting end controller receives a load charging instruction from the receiving end controller; the load charging instruction carries the receiving end power demand information i, such as current value information, voltage value information, or power value information.

Step S503: The transmitter controller calculates the required transformer output voltage, that is, the transformer secondary winding voltage, according to the receiver power demand information carried in the received load charging instruction and the detected coupling coefficient;

Step S504: The transmitter controller compares the voltage of the secondary winding of the transformer with the voltage range covered by each switch in the secondary winding, closes the corresponding switch, and connects the corresponding secondary winding to the circuit;

After the secondary winding of the transformer is connected to the circuit, the wireless charging system starts to charge, and alternating current is transmitted between the transmitting coil and the receiving coil through an alternating magnetic field. During the charging process, the transmitter and receiver compensation network adjust the impedance characteristics of the circuit to ensure the best transmission efficiency, and at the same time enable the control and drive of the inverter and rectifier to achieve closed-loop control.

Optionally, the receiving end of the wireless charging system further includes a rectifier overcurrent protection device. During the charging process, the rectifier overcurrent protection device continuously monitors whether the input current of the rectifier is overcurrent. If it is overcurrent, the main circuit is powered off. Stop charging, recheck the coupling coefficient and charging command, calculate the required transformer secondary winding voltage according to the new coupling coefficient and charging command, switch the corresponding switch, connect the corresponding winding to the circuit, and restart charging; if the rectifier is If the input current does not flow, continue charging until the end of charging.

An embodiment of the present application also provides a readable storage medium, the readable storage medium includes program instructions, and when the program instructions run on a processor, the wireless charging method process shown in FIG. 5 is implemented.

The following describes different implementations of this solution through different embodiments.

Method one, the transformer of the wireless charging transmitter device uses an isolation transformer. Isolation transformer means that the primary and secondary sides of the transformer are electrically isolated, and the primary winding of the transformer is connected to the inverter through a DC blocking capacitor.

The primary side of the isolation transformer of the wireless charging transmitter device can be a single winding 602 as shown in FIG. 6, or a double winding 402 as shown in FIG. 4, or a multi-winding. Specifically, the primary winding 602 of the transformer The number is the same as the number of inverters 601. Among them, when the number of primary windings is multiple, the input voltages of multiple inverters are connected in series. The input voltage of the inverter is variable, and can be adjusted by the front-end PFC circuit or a variable output DC power supply. When there are multiple inverters, the multiple inverters maintain synchronous control, that is, the switches of multiple inverters are enabled according to the same driving signal. If it is multi-winding, the number of turns of multiple primary windings of the transformer is the same, the number of secondary windings connected to the circuit is determined by the transformer output voltage calculated according to different working conditions, and the secondary winding is connected by the switch Into the circuit. The transmitting device further includes a transmitting end compensation network 603 and a transmitting coil 604. The wireless charging receiving device includes a receiving coil 605, a receiving end compensation network 606 and a rectifier 607, and the transmitting device forms a wireless charging system together.

FIG. 7 is a schematic diagram of a wireless charging system control provided by an embodiment of the present application. The actual power Po or output current Io or output voltage Vo output by the receiving end is related to the output power reference signal P _oref or the output current reference signal I _oref or output voltage. The reference signal V _oref is compared, and the difference between the reference signal and the actual signal calculated by the subtractor 704 is controlled by the compensator 702 to make the actual output signal Po/Io/Vo and the reference signal P _oref /I _oref /V _oref After the deviation of is multiplied by the transfer function G(s) of the compensator 702, the reference signal I _{Lpref of the} transmitting coil current is obtained directly or through conversion. According to the reference signal I _Lpref of the transmitting coil current, the transmitting coil current I _{Lp is} obtained, and then the transformer Secondary voltage. The difference between the reference signal I _Lpref of the transmitting coil current and the detection signal of the transmitting coil current is compared by the subtractor 703 to make the deviation of the transmitting coil current I _Lp and the transmitting coil current reference signal I _Lpref under the control of the compensator 701. Within range.

In an embodiment of the present application, the maximum output power of the wireless charging system Po=10kW, the voltage range of full power output Vo=320V-450V, the variation range of the coupling coefficient between the transmitting coil and the receiving coil is 0.1-0.26, and the inverter The input voltage of the converter is provided by the previous PFC circuit, and the range of the input phase voltage of the PFC circuit is 176Vp-253Vp.

The wireless charging transmitting device circuit and its corresponding receiving device circuit designed according to the above parameters are shown in Figure 8. The three-phase input voltage Va, Vb, and Vc are the power supply of the power factor correction circuit PFC, the output capacitance of the PFC is Co1 and Co2, and 0 is the midpoint of the output voltage of the PFC. Two identical inverters are connected to the output capacitors Co1 and Co2 of the PFC respectively, and the input voltages of the inverters are Vdc1 and Vdc2, respectively, and Vdc1=Vdc2. The midpoint voltages U1 and U2 of the bridge arms of the two inverters are the output voltages of the inverters. The midpoints of the bridge arms of the two inverters are respectively connected to the DC blocking capacitors Cdc1, Cdc2, and windings N1 and N2 of the transformer. The secondary side of the transformer has five windings N3-N7, and the five secondary windings of the transformer are respectively connected to the switch SW1-SW5. The switch here can be a mechanical switch, an electrical switch or a relay, etc., as long as it is a controllable switch. The other end of the switch is connected to the inductance Lf1 of the compensation network at the transmitting end, and the transmitting end compensation network is formed by Lf1, Cf1, and Cs1, and the transmitting coil is Lp. The receiving coil is Ls, and the receiving end compensation network is formed by Lf2, Cf2, and Cs2, and the receiving end rectifier is formed by the switch tubes Q1-Q4, and the Co output filter capacitor is connected to the load.

The circuit parameter design of this embodiment is as follows: Because the maximum instantaneous trip current of the domestic civil air switch is 32A, and the maximum power that a single-phase power supply can provide is 7kW, a single-phase power supply cannot be used when the output power is 10kW, and a three-phase power supply is required. power supply. From the above-mentioned minimum voltage range Vomin and output power Po conditions of full power output, the maximum allowable output current Iomax can be obtained by formula (1).

Assuming that the efficiency eff of the system is 91%, the input power Pin of the wireless charging system can be obtained from equation (2).

The input phase voltage range of PFC circuit is 176Vp-253Vp, usually PFC adopts three-phase three-wire structure, and the corresponding three-phase input line voltage is the phase voltage

The input line voltage range is 304V ₁ -438V ₁ , the use of pulse width modulation PWM or space vector modulation SVPWM can make the bus voltage of the power factor correction circuit 640Vdc-840Vdc, that is, the input voltage of the inverter can vary within 640Vdc-840Vdc. The voltages of Vdc1 and Vdc2 are equal, which is half of the output voltage of the power factor correction circuit, that is, the range of Vdc1 and Vdc2 is 320V-420V.

With reference to the parameters recommended in the wireless charging standard, the voltage stress of the transmitting coil and the receiving coil is preferably less than 1900V. Because the input voltage range of the inverter is 640-840V, assuming that the inverter adopts the driving mode that the tubes are turned on at the same time, the amplitude of the inverter's output voltage is the same as the input voltage, which is 320V-420V. The voltage stress on the transformer should be less than 1900V. Considering a certain margin, set the maximum transformation ratio of the transformer to 14:26, that is, when all windings on the secondary side of the transformer are connected, the maximum voltage is 840V*26/14=1560V, which meets Less than 1900V requirements.

The coupling coefficient between the transmitting coil and the receiving coil is determined by the relative position between the transmitting coil and the receiving coil, including the horizontal offset distance and the vertical distance between the coils. In the system design, the required power output can be satisfied in all ranges. The coupling coefficient between the coils and the inductance of the transmitting coil and the receiving coil need to be simulated with the help of magnetic simulation software. It is assumed that the minimum coupling coefficient kmin can reach 0.1 under the maximum vertical distance and maximum offset.

The power Po that the wireless charging transmitter can output is not only related to the coupling coefficient k, but also to the working frequency ω of the inverter and rectifier, the inductance Lp of the transmitting coil, the inductance Ls of the receiving coil, and the amount of power that can flow in the transmitting coil. The current ILp is related to parameters such as the current ILs that can flow in the receiving coil, and the calculation formula for the power Po that can be output at each moment is equation (3).

When designing system parameters, the maximum power can still be output when considering the worst working conditions. The worst working condition here is that under the minimum coupling coefficient kmin, the output voltage can still be at full power output. At this time, the current of the transmitting coil and the receiving coil are the largest, respectively, I _Lpmax and I _Lsmax , the maximum energy The calculation formula of output power is formula (4).

It can be seen from equations (3) and (4) that when the coupling coefficient and the working frequency ω are determined, the four parameters of Lp, Ls, ILpmax, and ILsmax have many combinations to meet the requirements of full power output. For the wireless charging of electric vehicles, the standard operating frequency range is 79kHz-90kHz, usually ω=2π·85kHz. The maximum current ILsmax of the receiving coil is related to the maximum output current I _omax . The maximum current ILsmax of the receiving coil is larger than the maximum output current I _omax . On the one hand, it is due to the influence of the voltage conversion of the rectifier and the other is the influence of reactive power. Assuming that the rectifier implements the same rectification method as uncontrolled rectification, the input current Irec of the rectifier is the output current Io of the rectifier

Times. The output of the rectifier is pure active power, and the receiving coil not only contains the active power required for the output, but also stores part of the reactive power, so the maximum current in the receiving coil is larger than the input current of the rectifier. The ratio of active power to reactive power within a certain range is more conducive to optimizing efficiency. When the reactive power is too large, the loss caused by the reactive current is large, and the reactive power is too small to be unable to transmit the power required by the receiving device. At the same time, when designing the system, it is necessary to consider the efficiency, heat dissipation capacity, volume, weight, cost and other aspects. Considering the above factors, determine a set of parameters Lp=75uH, Ls=43uH, I _Lpmax =75A, I _Lsmax =46A, the maximum power Pomax that can be output is calculated by formula (4) to be 10.46kW, which meets the design requirements.

The compensation network can choose the LCC structure with better characteristics. The two compensation networks of the LCC structure are shown in Figure 9. This structure has the characteristics of a current source. The transmitting coil current I _{Lp is} only related to the inverter output voltage U1, U2 and resonance inductance. Lf1 is related, and the current I _{Ls of the} receiving coil is only related to the input voltage Urec of the rectifier and the resonance inductance Lf2. Under the LCC compensation network structure, the relationship between the transmitting coil current ILp and the output voltage U1/U2 of the inverter and the resonance inductance Lf1 is shown in equation (5).

In formula (5), N _ps is the transformation ratio of the primary and secondary sides of the transformer, and the number of windings connected is different. In the case of the smallest coupling coefficient, only one winding N3 needs to be connected, and the transformation ratio at this time

θi is the phase shift angle between the two bridge arms before and after the full-bridge inverter circuit. In order to ensure the soft switching of the inverter switch tube, the phase shift angle θi between the bridge arms is taken as π, and the phase shift is maintained during all charging processes. The angle remains unchanged, and the relationship between the drive signal of each switch tube of the front and rear bridge arms of the inverter and the phase shift angle is shown in Figure 10. Among them, the drive signals of the switch tubes S1 and S2 on the same bridge arm are opposite, and the drive signals of S3 and S4 are opposite. The drive signals of different bridge arms are phase-shifted by θi, that is, the drive signals of S1 and S3 are phase-shifted by θi.

When the inverter input voltage Vdc1/Vdc2=320V, the required inverter output current I _{inv is the} largest.

From equation (5), we can get

The driving mode of the switching tube of the rectifier is the same as that of the inverter. The driving signals of the switching tubes Q1 and Q2 on the same bridge arm are opposite, and the driving signals of Q3 and Q4 are opposite. The driving signals of different bridge arms are shifted by the angle θr, that is, Q1 and The drive signal of Q3 is phase-shifted by θr. The phase shift angle of the rectifier can be adjusted and can be designed according to needs. When the output voltage is the lowest, the phase shift angle between the two bridge arms of the rectifier is θr=π, as shown in Figure 11, the embodiment uses θr=π as an example Design, the phase shift angle at other output voltage Vo passes

It can be calculated that the input current of the rectifier is the same as the input current when the output voltage is 320V by adjusting the phase shift angle θr.

When the minimum output voltage is 320V, the size of the resonant inductance Lf2 at the receiving end can be calculated by formula (6).

Assuming that the efficiency of the power factor correction circuit is 98.5%, the input power P _{inv of} the inverter is obtained by equation (7).

P _inv ＝11kW*98.5%＝10.84kW (7)

From equation (8), the maximum output current I _{inv_max} of the inverter can be calculated to be 21.9A.

The selection principle of designing the number of secondary windings of the transformer is: when the inverter input voltage is in the range of 640Vdc-840Vdc and the coupling coefficient is in the range of 0.1-0.26, it can meet all the charging requirements of the load. The worst working condition is when the minimum coupling coefficient k=0.1, when the output voltage is 320V, the maximum power can be output 10kW.

After calculation, it is assumed that the number of turns of the two windings N1 and N2 on the primary side is 7, the number of turns of the first winding on the secondary side is N3=12, the number of turns of the second winding N4=2, and the number of turns of the third winding The number of turns N5=3, the number of turns of the fourth winding N6=4, and the number of turns of the fifth winding N7=5. In this way, when the secondary side only connects to N3, when the inverter input voltage changes within the range of 320V-420V, the voltage range that can be covered on the corresponding transformer secondary winding N3 is obtained by equation (9).

It is calculated that the voltage range across N3 is 548V-720V when only winding N3 is connected. By analogy, it can be calculated that the adjustable voltage range when N3 and N4 are connected at the same time is 640V-840V, and N3, N4, and N5 are connected at the same time. The adjustable voltage range is 774V-1020V when N3, N4, N5, and N6 are connected at the same time, and the adjustable voltage range is 960V-1260V when N3, N4, N5, N6, and N7 are connected at the same time. It is 1189V-1560V. Every time a winding is added, the voltage can cover the range before the increase. As shown in Figure 12, all voltage ranges can be covered, so seamless switching between various working states can be realized.

Cf1 and Cf2 in the compensation network can be calculated by the operating frequency ω, and the relationship between the operating frequency ω and Lf1, Cf1, Lf2, and Cf2 is represented by equation (10).

Equation (10) can be obtained

The capacitance Cs1 connected in series with the transmitting coil in the compensation network is obtained by the following formula (11).

The capacitance Cs2 connected in series with the receiving coil in the compensation network is obtained by the following formula (12).

From the formula (11), Cs1=55.9pF, and from the formula (12), Cs2=121.1pF.

The wireless charging system of the above embodiment is used to charge the load. Assuming that the coupling coefficient between the transmitting coil and the receiving coil is k=0.2, the charging current required by the load is 25A, and the full power is 10kW output. In this case, the charging process is as follows:

1. The transmitter controller transmits a low-power magnetic field through the transmitter coil, and detects the coupling coefficient between the coils k=0.2 according to the received feedback.

2. The transmitting end controller receives the load charging indicator i from the receiving end controller through wireless communication; the load charging instruction carries the power demand information of the receiving end load current of 25A and power of 10kW.

3. The transmitter controller adjusts the bridge arm of the rectifier according to the input voltage range of the inverter 640V-840V, the received instruction load current 25A, the charging command of the power 10kW information, and the detected coupling coefficient 0.2 through formula (6) The phase shift angle θr makes the input current and coil current of the rectifier the same as 320V. The formula (3) can be used to obtain half of the transmitter coil current when it becomes the maximum current, that is, 37.5A, and the corresponding ILf1 becomes half when the maximum current is At 10.9A, dividing the power by the current can get the secondary voltage of the transformer to be 10.48kW/10.9A=961.5V. It can be seen from Figure 11 that 3 windings need to be connected.

4. The transmitter controller closes the corresponding switches SW1, SW2, SW3, and connects the corresponding secondary windings N3, N4, N5 to the circuit;

After the transformer winding is connected to the circuit, the wireless charging system starts to charge, and alternating current is transmitted between the transmitting coil and the receiving coil through an alternating magnetic field. During the charging process, the transmitter and receiver compensation network adjust the impedance characteristics of the circuit to ensure the best transmission efficiency, and at the same time enable the control and drive of the inverter and rectifier to achieve closed-loop control.

Optionally, during the charging process, the rectifier overcurrent protection device continuously monitors whether the input current _{Irec of the} rectifier is overcurrent, and if it is overcurrent, the charging is stopped; then the transmitter controller re-detects the coupling coefficient, and according to the new coupling coefficient, Calculate the required output voltage of the transformer with the converter input voltage range and load charging command, and switch the corresponding switch, connect the corresponding winding to the circuit, and the wireless charging system circuit restarts charging; if the input current of the rectifier does not flow, continue charging Until the end of charging.

Method two, the transformer uses a non-isolated transformer. Non-isolated transformer means that the primary and secondary sides of the transformer share some windings, and the primary winding of the non-isolated transformer is connected to the inverter through a blocking capacitor.

The primary and secondary sides of the non-isolated transformer have one or more common windings, and the primary and secondary sides can share one winding as shown in Fig. 13A, or can share multiple windings, as shown in Fig. 13B. If it is multi-winding, the input voltages of multiple inverters are connected in series. The input voltage of the inverter is variable and can be adjusted by outputting a variable DC power supply or the PFC circuit of the previous stage. When there are multiple inverters, the inverters maintain synchronous control, that is, the switches at the same position are used The same drive signal. If it is multi-winding, the number of turns of multiple primary windings of the transformer is the same, the number of secondary windings connected to the circuit is determined by the transformer output voltage calculated according to different working conditions, and the secondary winding is connected by the switch Into the circuit.

In the embodiment of this method, a wireless charging system with the same specifications as the previous embodiment is adopted, that is, the output power of the wireless charging system is Po=10kW, the full power output voltage range Vo=320V-450V, and the distance between the transmitting coil and the receiving coil is The variation range of the coupling coefficient is 0.1-0.26, and the range of the input phase voltage is 176Vp-253Vp. The circuit designed according to the above parameters is shown in Figure 14.

The principle and method of designing with a non-isolated transformer are similar to the first embodiment, except that the winding on the primary side of the transformer and one winding on the secondary side are shared. Set the number of turns of the primary and secondary side common winding N21=14, which is the same as the primary side N1=N2=7, the secondary side N3=12, and N4=2 in the transformation ratio in the previous embodiment, both are 1:1. The other three winding turns are N22=3, N23=4, and N24=5.

The parameters of the compensation network are also the same, and the voltage range that can be covered under each winding is the same except that the shared winding is the sum of the ranges covered by N3+N4 in the first embodiment.

The working process of this mode is similar to that in the previous mode, and will not be repeated.

In another embodiment of the present application, the transformer is an isolation transformer, the output power of the wireless charging system is 6 kW, and a single-phase input is adopted. The circuit structure diagram is shown in FIG. 15. The output voltage range and coupling coefficient are the same as the previous embodiment. There is only one inverter in the charging circuit of this embodiment, one winding on the primary side of the isolation transformer, and five switchable windings on the secondary side. The circuit parameter design method and charging process are similar to those in the previous embodiment, and will not be repeated here.

In another embodiment of the present application, the transformer is a non-isolated transformer, and there are two common windings. The circuit structure diagram is shown in FIG. 16. The output voltage range and coupling coefficient are the same as the previous embodiment. There are two identical inverters in the charging circuit of this embodiment. The isolation transformer has one winding on the primary side and five switchable windings on the secondary side. The circuit parameter design method and charging process are similar to those in the previous embodiment. Do not go into details.

In the embodiments of the present application, the inverter phase shift angle is unchanged, and the rectifier phase shift angle is variable. Both the inverter phase shift angle and the rectifier phase shift angle are variable or invariable.

It should be noted that the transmitter controller and the receiver controller in the embodiments of the present application may be implemented by hardware circuits, or may be implemented by software. When the transmitter controller or the receiver controller is implemented by software, the wireless charging system includes a processor, and the processor implements the certain (or certain) units (or devices) by running program instructions.

The processor may be a central processing unit, a general-purpose processor, a digital signal processor, an application specific integrated circuit, a programmable gate array or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. It can implement or execute various exemplary logical blocks, modules and circuits described in conjunction with the disclosure of this application. The processor may also be a combination that implements computing functions, for example, a combination of one or more microprocessors, a combination of a digital signal processor and a microprocessor, and so on. In addition, the memory may include various media capable of storing program codes, such as ROM or random storage RAM, magnetic disk or optical disk.

The above are only the preferred embodiments of the present invention, and do not limit the present invention in any form. Although the present invention has been disclosed as above in preferred embodiments, it is not intended to limit the present invention. Anyone familiar with the art, without departing from the scope of the technical solution of the present invention, can use the methods and technical content disclosed above to make many possible changes and modifications to the technical solution of the present invention, or modify it into equivalent changes. Examples. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the technical solutions of the present invention still fall within the protection scope of the technical solutions of the present invention.

Claims

A wireless charging and transmitting device, characterized by comprising: one or more inverters, a transformer connected to the one or more inverters, the transformer including one or more primary windings and a plurality of secondary A side winding, a transmitting end compensation network connected to the transformer, a transmitting coil connected to the transmitting end compensation network, and a transmitting end controller, wherein:

The one or more inverters are used to convert the input direct current into alternating current;

The transmitter controller is used to control one or more winding access circuits in the secondary windings of the transformer, wherein different secondary winding access circuits provide different transformer output voltages;

The transformer is used to receive the alternating current output by the inverter and output the transformed alternating current;

The transmitting end compensation network is used to compensate the transformed alternating current and send it to the transmitting coil;

The transmitting coil is used to transmit the alternating current output by the compensation network through an alternating magnetic field.
The transmitting device according to claim 1, wherein each of the plurality of secondary windings is respectively connected to a switch, and the transmitting end controller is used to control the switch to switch the corresponding secondary windings Access the circuit.
The transmitting device according to claim 1, wherein the ratio of the output voltage of the inverter to the output voltage of the transformer is equal to the total number of turns of the transformer primary winding and the transformer access circuit The ratio of the total number of turns of the secondary winding.
The transmitting device according to claim 1, wherein the input voltage of the inverter is variable.
The transmitting device according to claim 1, wherein the output voltage of the transformer is determined according to the power demand of the wireless charging receiving end and the coupling coefficient between the transmitting coil and the receiving coil of the wireless charging receiving end, and the power demand is The output power or charging current or charging voltage of the wireless charging transmitter required by the receiving end.
The transmitting device according to claim 5, wherein the output power of the wireless charging transmitting device
The transformer output voltage Vac is proportional to the output power Po of the transmitting device, and inversely proportional to the transmitting coil current I Lp , where k represents the coupling coefficient between the transmitting coil and the receiving coil, and ω represents the inverter and the For the operating frequency of the rectifier at the receiving end, Lp represents the inductance of the transmitting coil, Ls represents the inductance of the receiving coil, I Lp represents the current of the transmitting coil, and I Ls represents the current of the receiving coil.
The transmitting device according to any one of claims 1-6, wherein the number of primary windings of the transformer is the same as the number of the inverters.
The transmitting device according to any one of claims 1-6, further comprising a DC blocking capacitor, and the transformer primary winding is connected to the inverter through the DC blocking capacitor.
The transmitting device according to any one of claims 1-6, wherein the transformer is an isolation transformer, the primary winding and the secondary winding of the isolation transformer are electrically isolated, or the transformer is non-isolated For the transformer, the primary side and the secondary side of the non-isolated transformer share partial windings.
A wireless charging method, characterized in that the wireless charging method is applied to the transmitting device of claims 1-9; the method comprises:

One or more of the secondary windings of the transformer is controlled to be connected to the circuit, wherein different secondary windings are connected to the circuit to provide different transformer output voltages.
The wireless charging method according to claim 10, further comprising:

The output voltage of the transformer is determined according to the power demand of the wireless charging receiving end and the coupling coefficient between the transmitting coil and the receiving coil of the wireless charging receiving end, and the power demand is the output of the wireless charging transmitting device required by the receiving end The amount of power or charging current or charging voltage.
The wireless charging method according to claim 10, wherein the output power of the wireless charging transmitter is
The transformer output voltage Vac is proportional to the output power Po of the transmitting device, and inversely proportional to the transmitting coil current I Lp , where k represents the coupling coefficient between the transmitting coil and the receiving coil, and ω represents the inverter and the For the operating frequency of the rectifier at the receiving end, Lp represents the inductance of the transmitting coil, Ls represents the inductance of the receiving coil, I Lp represents the current of the transmitting coil, and I Ls represents the current of the receiving coil.
The wireless charging method according to claim 11, further comprising:

A load charging instruction is received, where the load charging instruction carries the power demand of the wireless charging receiving end.
A wireless charging system, characterized by comprising the wireless charging transmitting device and the wireless charging receiving device according to any one of claims 1-9;

The wireless charging receiving device includes: a receiving coil, a receiving end compensation network connected to the receiving coil, and a rectifier connected to the receiving end compensation network; wherein:

The receiving coil is used to receive an alternating magnetic field and output alternating current;

The receiving end compensation network is configured to compensate the alternating current output by the receiving coil and output it to the rectifier;

The rectifier is used to rectify the alternating current output by the compensation network into direct current.
The wireless charging system according to claim 14, wherein the wireless charging receiving device further comprises: a receiving end controller, configured to send a load charging instruction to the transmitting end controller, wherein the load charging instruction carries Wireless charging receiver power requirements.