WO2022021201A1

WO2022021201A1 - Wireless charging device and method of measuring temperature of wireless charging coil

Info

Publication number: WO2022021201A1
Application number: PCT/CN2020/105779
Authority: WO
Inventors: 刘宗文; 王胆; 刘浩东
Original assignee: 华为技术有限公司
Priority date: 2020-07-30
Filing date: 2020-07-30
Publication date: 2022-02-03
Also published as: CN114365376A

Abstract

Embodiments of the present application comprise a wireless charging device, relating to the field of wireless charging, and comprising a wireless charging circuit and a temperature sensor. The wireless charging circuit rectifies an induced current generated by a wireless charging coil, and outputs a DC charging current. The temperature sensor acquires a first voltage between two ends of the wireless charging coil, acquires a first current flowing through the wireless charging coil, and determines a temperature corresponding to the wireless charging coil according to the first voltage and the first current. The first voltage is a DC voltage or a low-frequency AC voltage, and the first current is a DC current or a low-frequency AC current. In this way, the temperature corresponding to the wireless charging coil can be directly calculated according to characteristics of the wireless charging coil itself, such that the temperature of an internal induction coil of a terminal can be monitored accurately and promptly, thereby improving the safety and reliability of the charging device.

Description

A wireless charging device and a temperature detection method for a wireless charging coil

technical field

The embodiments of the present application relate to the field of wireless charging, and in particular, to a wireless charging device and a temperature detection method for a wireless charging coil.

Background technique

Wireless charging technology is gradually popularized in terminal electronic products. Its working principle is that the wireless charger is encapsulated with a transmitting coil, and an alternating current of a certain frequency is passed through the transmitting coil. The induced current is rectified and supplied to the terminal device, thereby realizing the charging process of the terminal power supply; therefore, the wireless charging technology is to provide the induced current generated by the wireless charging coil to the terminal's power supply device to complete the power supply charging technology.

In order to achieve fast charging of the terminal, the charging power will be higher and higher, and may reach more than 100w in the future; in the high-power charging scenario, the temperature of the receiving coil will be higher and higher; since the charging coil is usually mounted on the terminal In the battery area, when the coil temperature is too high, there will be reliability risks and even damage to the terminal components. Therefore, accurately obtaining the terminal-side charging coil temperature becomes an important basis for designing terminal equipment protection strategies. The existing temperature measurement method is as follows: a thermistor is mounted around the wireless charging coil, and the negative temperature coefficient of the thermistor is used to calculate the temperature; specifically, the thermistor senses the temperature of the wireless charging coil through heat radiation or heat conduction. Change, calculate the current temperature according to the change of the resistance value of the thermistor.

This method indirectly calculates the coil temperature through the change in the resistance of the thermistor. In fact, due to the loss of temperature in the process of heat conduction, the environment where the thermistor is located is not consistent with the environment around the coil, and it is affected by the work of other components. The calculated temperature is quite different from the actual temperature of the coil; at the same time, heat radiation or heat conduction requires transmission time, this method of measuring temperature will cause a time delay in the calculated temperature, and the ability to perceive temperature will deteriorate. Therefore, how to monitor the temperature of the induction coil inside the terminal more accurately and efficiently has become an urgent problem to be solved.

SUMMARY OF THE INVENTION

The embodiment of the present application provides a temperature detection method for a wireless charging device and a wireless charging coil, which is used to monitor the temperature of the induction coil inside the terminal more accurately and in a timely manner.

A first aspect of the embodiments of the present application provides a wireless charging device, including: a wireless charging circuit and a temperature detector. The wireless charging circuit will receive the induced current generated by the wireless charging coil, rectify the induced current, and output a DC charging current to charge the battery in the electronic device. The temperature detector calculates the corresponding temperature by obtaining the first voltage at both ends of the wireless charging coil and the first current flowing through the wireless charging coil; therefore, the temperature detector is realized by converting voltage and current to temperature. A circuit for temperature detection instead of a traditional temperature detector. It can be understood that the first voltage obtained by the temperature detector is a DC voltage or a low-frequency AC voltage, and the first current obtained is a DC current or a low-frequency AC current. The temperature corresponding to the charging coil.

The wireless charging device provided by the embodiment of the present application can calculate the temperature corresponding to the wireless charging coil according to the obtained first voltage at both ends of the wireless charging coil and the first current flowing through the wireless charging coil. The corresponding temperature of the charging coil can be calculated based on its own characteristics, and the real state of the wireless charging coil can be obtained in a more timely manner, so that the temperature of the induction coil inside the electronic device can be monitored more accurately and in a timely manner, so as to provide timely security for it in the future. Protective measures to improve the safety and reliability of charging equipment.

In conjunction with the first aspect of the embodiments of the present application, in the first implementation of the first aspect of the embodiments of the present application: it can be understood that the temperature detector includes a detection module and a temperature calculation module, and the temperature calculation module will A voltage and a first current are used to determine the DC impedance of the wireless charging coil, and then the temperature of the coil is determined according to the change of the DC impedance, so as to accurately and timely monitor the temperature of the wireless charging coil. Optionally, the temperature operation module includes at least one of an analog circuit, a digital logic circuit or a processor, wherein the processor can run software to perform the operation.

With reference to the first implementation of the first aspect of the embodiments of the present application, in the second implementation of the first aspect of the embodiments of the present application: the DC impedance of the wireless charging coil material and metal changes with the change of temperature , and the temperature coefficient of resistance is a physical quantity used to reflect the ability of the metal DC impedance to change with temperature, that is, the relative change of the resistance value when the temperature of the metal changes by 1 degree Celsius; in this way, the temperature detection module can be based on the first voltage and the first voltage. A current, the change of the DC impedance of the wireless charging coil is determined in real time, and then the temperature change is calculated back according to the change, so as to determine the corresponding temperature.

In this embodiment, the corresponding temperature of the wireless charging coil is directly determined according to the change of the DC impedance of the wireless charging coil, and the corresponding temperature can be monitored in a more timely manner; there is no need for other separate temperature detection devices to measure the temperature separately, only the wireless charging The voltage at both ends of the coil and the current flowing through the wireless charging coil can be measured, and the operation is more convenient.

With reference to the first aspect of the embodiments of the present application to the second implementation of the first aspect, in the third implementation of the first aspect of the embodiments of the present application: the temperature detector may include a voltage detection module and a current detection module, The voltage detection module is used to measure the first voltage across the wireless charging coil; and the current detection module needs to provide a conduction loop for the wireless charging coil, generate a first current on the loop, and measure the first current at the same time. Through the first voltage measured by the voltage detection module and the first current measured by the current detection module, the corresponding DC impedance can be directly determined, which provides conditions for calculating the temperature of the wireless charging coil.

With reference to the third implementation of the first aspect of the embodiments of the present application, in the fourth implementation of the first aspect of the embodiments of the present application: it can be understood that the wireless charging device further includes a capacitor, and the wireless charging coil One end is connected to the first input end of the wireless charging module through a capacitor, and the second end of the wireless charging coil is connected to the second input end of the wireless charging module.

With reference to the third implementation of the first aspect or the fourth implementation of the first aspect of the embodiments of the present application, in the fifth implementation of the first aspect of the embodiments of the present application: current detection in a wireless charging device The module may also include a DC power supply that directly provides the DC power to the wireless charging coil to generate a first current flowing through the wireless charging coil.

With reference to the third implementation of the first aspect or the fifth implementation of the first aspect of the embodiments of the present application, in the sixth implementation of the first aspect of the embodiments of the present application: the wireless charging device further includes at least one The inductor is connected to the current detection module and the wireless charging coil. Its function is to block the high-frequency AC current on the conduction loop, so that the current detection module can detect the DC current or low-frequency AC current flowing through the wireless charging coil, which is convenient for obtaining the wireless charging coil. DC impedance.

With reference to the third implementation of the first aspect or the sixth implementation of the first aspect of the embodiments of the present application, in the seventh implementation of the first aspect of the embodiments of the present application: a filter is further included, connected to The voltage detection module, when the voltage detection module detects the voltage at both ends of the wireless charging coil, is used to filter the voltage at both ends of the wireless charging coil, and then obtain its corresponding DC voltage or low-frequency AC voltage, thereby obtaining the DC impedance of the wireless charging coil. .

With reference to the first aspect to the seventh implementation manner of the first aspect of the embodiments of the present application, in the eighth implementation manner of the first aspect of the embodiments of the present application, the wireless charging device may include the wireless charging coil.

A second aspect of the embodiments of the present application provides a method for detecting temperature of a wireless charging coil, including: the wireless charging process is that the wireless charging coil and an external coil generate an induced current through electromagnetic induction and magnetoelectric induction, and then the wireless charging circuit receives the induced current , rectify the induced current and output the DC charging current to the power supply to be charged; to measure the temperature of the wireless charging coil, first obtain the DC voltage or low-frequency AC voltage at both ends of the wireless charging coil; The direct current or low frequency alternating current of the charging coil, and then determine the temperature corresponding to the wireless charging coil according to the obtained current and voltage.

Using this method to measure the temperature of the wireless charging coil, the system does not need to directly measure the temperature of the wireless charging coil, but calculates the corresponding temperature according to the corresponding current and voltage of the wireless charging coil, so that the corresponding temperature can be monitored in a more timely manner; It only needs to measure the voltage at both ends of the wireless charging coil and the current flowing through the wireless charging coil to obtain the corresponding temperature, and the operation is more convenient.

In combination with the second aspect of the embodiments of the present application, in the first implementation of the second aspect of the embodiments of the present application: specifically, firstly, according to the DC voltage or low-frequency AC voltage at both ends of the wireless charging coil, and the flow through the wireless charging coil The direct current or low frequency alternating current of the charging coil determines the direct current impedance of the wireless charging coil; then the temperature is determined according to the direct current impedance.

Due to the material of the wireless charging coil, the DC impedance of the metal usually changes with the change of temperature. Therefore, the change in temperature can be inversely calculated through the change of the DC impedance corresponding to the wireless charging coil, so as to determine the temperature corresponding to the wireless charging coil. In this way, the real state of the wireless charging coil can be acquired in a more timely manner, so that the temperature of the induction coil inside the terminal can be monitored more accurately and in a timely manner, so as to provide timely safety protection measures for it in the future, and improve the safety and reliability of the charging equipment.

A third aspect of the embodiments of the present application provides an electronic device, including the wireless charging device described in the first aspect or any of the implementation manners, and a wirelessly charged battery.

Optionally, the electronic device is a terminal.

In the technical solution provided by the embodiment of the present application, the temperature detector first needs to obtain the first voltage at both ends of the wireless charging coil and the first current flowing through the wireless charging coil, and then calculate the wireless charging coil according to the first current and the first voltage. The temperature corresponding to the charging coil, in this way, the corresponding temperature of the wireless charging coil can be calculated directly according to its own characteristics, and the real state of the wireless charging coil can be obtained in a more timely manner, so that the internal induction of the electronic device can be monitored more accurately and in a timely manner. The temperature of the coil can be used to provide timely safety protection measures to improve the safety and reliability of the charging equipment.

Description of drawings

FIG. 1 is an impedance temperature curve diagram of a wireless charging coil provided by an embodiment of the present application;

FIG. 2 is a schematic structural diagram of a wireless charging device according to an embodiment of the present application;

FIG. 3 is a schematic structural diagram of another wireless charging device provided by an embodiment of the present application;

FIG. 4 is a schematic flowchart of a temperature detection method for a wireless charging coil provided by an embodiment of the present application.

detailed description

The embodiment of the present application provides a temperature detection method for a wireless charging device and a wireless charging coil, which is used to monitor the temperature of an induction coil inside an electronic device more accurately and in a timely manner.

The wireless charging technology uses the principles of electromagnetic induction and magnetoelectric induction to charge. The principle is similar to that of a transformer. There is a coil at the sending end and the receiving end. The electromagnetic signal generates an induced current, and then rectifies the induced current to output a charging current, thereby completing the battery charging process. As a technology that uses electromagnetic conversion to transmit energy, wireless charging technology will be limited by distance and conversion efficiency. Among them, the farther the wireless energy transmission distance is, the greater the power consumption will be, and the higher the energy consumption of the device will be; at the same time, the conversion efficiency of this technology will be low, and its charging speed and charging efficiency will be relatively slow. In order to improve the charging speed of wireless charging, the charging power in the future will be higher and higher, which may reach more than 100w. In high-power charging scenarios, the temperature of the charging coil will be maintained at a high level. Usually, electronic devices, such as terminals As the receiving end, the charging coil included in it is usually mounted in the battery area, and is isolated by a protective film in the middle.

During the charging process of electronic devices, the charging coil will generate a temperature rise, which will not only affect the charging coil itself, but also affect the battery and other components. When the charging coil temperature is too high, it can create reliability risks and even damage other components. Therefore, it is necessary to obtain the temperature of the charging coil in real time, and specify corresponding protection measures according to the temperature. Therefore, obtaining the temperature of the charging coil on the receiving end side in a timely and accurate manner has become an urgent problem to be solved; the traditional thermistor is used to measure the wireless charging coil. There are many defects in the technology of high temperature, for details, please refer to the introduction of the background technology. In view of this, the embodiments of the present application mainly use the relationship between the resistivity of metal and temperature to measure the temperature of the wireless charging coil.

The material of the wireless charging coil is usually metal. The resistivity of the metal is a physical quantity used to represent the resistance characteristics of various substances. It reflects the properties of the metal's resistance to current, which is related to the type of metal and is also affected by temperature. The temperature coefficient of resistance represents the relative change in the resistance value of a metal when the temperature of the metal changes by 1 degree Celsius. That is, a DC or low-frequency current path is set for the wireless charging coil, and the DC impedance of the wireless charging coil is determined by measuring the voltage and current of the low-frequency path, so as to calculate the DC impedance change according to the resistance temperature coefficient of the wireless charging coil, and inversely calculate the coil. The real temperature is provided to the charging system, which can provide parameter input for reliability safety protection measures and improve the system reliability protection accuracy.

Exemplarily, the temperature coefficient of resistance of the wireless charging coil can be obtained in the following manner. At a constant room temperature of 25°, the impedance value R0 of the wireless charging coil is obtained by means of pressure current measurement and the impedance temperature curve is drawn to obtain the temperature coefficient of resistance, as shown in Fig. 1 provides an impedance temperature curve diagram of a wireless charging coil, as shown in Figure 1, the material of the wireless charging coil is copper, first measure the DC impedance of the wireless charging coil in different temperature environments, and then determine the impedance and The temperature coordinates of the temperature, and then curve fitting multiple points to obtain the resistance temperature coefficient. It is understandable that the impedance temperature curve shown in Figure 1 is a linear fit, that is, the wireless charging coil has a stable resistance. The temperature coefficient, which is the slope of the line. When the temperature coefficient of resistance of the wireless charging coil is obtained, the corresponding temperature can be inversely calculated.

FIG. 2 is a schematic structural diagram of a wireless charging device according to an embodiment of the present application. The wireless charging device is included in an electronic device, and the electronic device is a terminal as an example for introduction in the following. In addition to the wireless charging device shown in FIG. 2 , the terminal also includes a battery, a screen, an antenna, a sensor, and other necessary functional circuits, which are not described in this embodiment. As shown in FIG. 2, the wireless charging device may be a receiving device PRX; and the receiving device PRX includes a wireless charging coil L2, a wireless charging circuit and a temperature detector. Wherein, the temperature detector further includes a voltage measurement module, a current measurement module and a temperature calculation module. The receiving device PTX receives the electromagnetic signal sent by the transmitting end PTX of the wireless charging, and the transmitting end PTX can generate a current in its internal transmitting coil and form the electromagnetic signal. The receiving device PRX converts the electromagnetic signal into a charging signal, such as a current, through the principle of magneto-electric induction.

The first end (A4 end) of the wireless charging coil L2 is connected to one end of the wireless charging circuit through the capacitor C, and the second end (A3 end) of the wireless charging coil L2 is connected to the other end of the wireless charging circuit; the wireless charging coil L2 The first end (A4 end) of the wireless charging coil is connected to the A1 end of the voltage detection module in the temperature detector, and the second end (A3 end) of the wireless charging coil L2 is connected to the A1 end of the voltage detection module in the temperature detector; the wireless charging coil L2 The first end (A4 end) of the temperature detector is connected to the input end of the current detection module in the temperature detector through an inductor, and the other end of the current detection module is grounded; inside the temperature detector, the voltage detection module and the current detection module are respectively connected with the temperature operation The modules are connected to provide detection data for the temperature operation module.

It can be understood that the wireless charging coil L2 is used to receive the electromagnetic signal sent by the charging coil L1 in the transmitting device PTX, and generate an induced current through the phenomenon of magnetoelectric induction; the capacitor C is used to store energy and supply power to the wireless charging circuit; It is used to rectify the induced current generated by the wireless charging coil L2, and then output the DC charging current to the battery of the terminal; the inductance is used to block the high-frequency AC current flowing into the current detection module from the wireless charging coil L2; in the temperature detector, the current The detection module is used to provide a DC or low-frequency AC path for the wireless charging coil L2, and measure the DC current or low-frequency AC current flowing through the wireless charging coil L2 on the path; and the voltage detection module in the temperature detector is used to detect the wireless charging coil L2. The DC voltage or low-frequency AC voltage at both ends of the charging coil L2; the temperature calculation module in the temperature detector is used to receive the data provided by the voltage detection module and the current detection module, and then calculate according to the data to determine the temperature corresponding to the wireless charging coil L2 .

Exemplarily, the working process of the receiving device PRX may be as follows: the charging coil L1 in the transmitting device PTX is supplied with high-frequency alternating current, and electromagnetic induction and magneto-electric induction phenomena occur with the wireless charging coil L2, and the wireless charging coil L2 generates an induced current immediately. , the induced current is input to the wireless charging circuit through the capacitor C, and the wireless charging circuit rectifies it and provides a DC charging current to the battery of the terminal.

Among them, the wireless charging circuit can be a rectifier circuit, and its function can be to convert the alternating current generated by the wireless charging coil into a unidirectional pulsed direct current. Circuit or bridge rectifier circuit, the specific form is not limited.

When determining the temperature of the wireless charging coil L2, one end of the current detection device is connected to one end of the wireless charging coil L2 through an inductance, and the other end is grounded. In this way, when the current detection module is turned on, the current detection module provides a direct current for the wireless charging coil L2. Or the low-frequency AC path, extract the DC current or low-frequency AC current Is in the wireless charging circuit; wherein, the path of Is is from the wireless charging circuit to the A3 end of the wireless charging coil L2, through the wireless charging coil L2 to the A4 end, and then through the inductor. It flows into the current detection module and finally reaches the ground to form a complete closed loop; the current detection module measures is to obtain the current value of the first current.

Then, the voltage detection module measures the first voltage across the wireless charging coil L2. It can be understood that the first voltage is also a DC voltage or a low-frequency AC voltage, and corresponds to a DC current or a low-frequency AC current; exemplarily, the voltage detection module may It is connected to the wireless charging coil L2 through the filter, and then measured to obtain the voltage value of the first voltage.

After the current value of the first current and the voltage value of the first voltage are determined, the voltage detection module and the current detection module transmit the data to the temperature calculation module; wherein the calculation module may include at least one of an analog circuit, a digital logic circuit, or a processor. Item, wherein the processor is capable of running software to perform the following operations. Processors include but are not limited to central processing unit (CPU), neural network processing unit (NPU), application processor (AP), modem processor, graphics processing unit (GPU) ), controller, video codec, digital signal processor (DSP) or baseband processor.

Exemplarily, the temperature detection module first determines the DC impedance of the wireless charging coil L2 according to the current value of the first current and the voltage value of the first voltage, for example, according to the formula R=V/I, where R is the DC impedance, V is the voltage value of the first voltage, and I is the current value of the first current.

After the DC impedance of the wireless charging coil L2 is determined, the temperature detection module can determine the corresponding temperature according to the stored impedance-temperature correspondence table, wherein the impedance-temperature correspondence table is the DC impedance drawn according to the resistance temperature coefficient of the wireless charging coil L2 Correspondence table with temperature; the temperature detection module can also directly calculate the temperature according to the resistance temperature coefficient η of the wireless charging coil L2, for example, the temperature can be calculated inversely by the formula R=R0*[1+η*(T-25)], Among them, R is the measured current DC impedance, R0 is the DC impedance corresponding to the wireless charging coil L2 at 25 degrees, and T is the current temperature value to be determined; it can be understood that T=25+( R-R0)/(R0*η), that is, according to this formula, the DC impedance R of the wireless charging coil L2 determined by the temperature calculation module can be brought in to obtain the temperature corresponding to the wireless charging coil L2.

Understandably, since it is necessary to obtain the temperature of the charging coil in time, and specify corresponding protection measures according to the temperature, exemplarily, the system can set a detection cycle, detect and calculate the temperature of the wireless charging coil L2 once in each cycle, and timely and Effective feedback of the temperature of the wireless charging coil L2.

In the technical solution provided in this embodiment, the temperature detector first needs to obtain the first voltage across the wireless charging coil and the first current flowing through the wireless charging coil, and then calculate the wireless charging according to the first current and the first voltage In this way, the corresponding temperature of the wireless charging coil can be calculated directly according to its own characteristics, and the real state of the wireless charging coil can be obtained in a more timely manner, so that the internal induction coil of the terminal can be monitored more accurately and in a timely manner. temperature, so as to provide timely safety protection measures to improve the safety and reliability of charging equipment.

FIG. 3 is a schematic structural diagram of another wireless charging device provided by an embodiment of the application. As shown in FIG. 3, similar to FIG. 2, the wireless charging device also includes a receiving device PRX; and the receiving device PRX includes a wireless charging coil L2, Wireless charging circuit and temperature detector. Wherein, the temperature detector further includes a voltage measurement module, a current measurement module and a temperature calculation module, and the current measurement module further includes a DC power supply.

Among them, the first end (A4 end) of the wireless charging coil L2 is connected to one end of the wireless charging circuit through the capacitor C, and the second end (A3 end) of the wireless charging coil L2 is connected to the other end of the wireless charging circuit. It can be understood that, The wireless charging circuit is not shown in FIG. 3, but its equivalent resistance _RL is given instead. The first end (A4 end) of the wireless charging coil L2 is connected to one end of the voltage detection module in the temperature detector through a filter , the second end (A3 end) of the wireless charging coil L2 is connected to the other end of the voltage detection module in the temperature detector through the filter; the first end (A4 end) of the wireless charging coil L2 is connected to the current in the temperature detector through the inductor L3 The A1 end of the detection module is connected, and the second end (A3 end) of the wireless charging coil L2 is connected to the A2 end of the current detection module in the temperature detector through the inductor L4; inside the temperature detector, the voltage detection module and the current detection module are respectively connected to The temperature operation module is connected to provide detection data for the temperature operation module.

It can be understood that the wireless charging coil L2 is used to receive the electromagnetic signal sent by the charging coil L1 in the transmitting device PTX, and generate an induced current through the phenomenon of magnetoelectric induction; the capacitor C is used to store energy and supply power to the wireless charging circuit; It is used to rectify the induced current generated by the wireless charging coil L2, and then output the DC charging current to the battery of the terminal; the inductance is used to block the high-frequency AC current on the current loop corresponding to the wireless charging coil L2 and the current detection module; the filter is It is used to filter the high-frequency AC voltage at both ends of the wireless charging coil L2 to generate a DC voltage or a low-frequency AC voltage; in the temperature detector, the current detection module is used to provide a DC or low-frequency AC path for the wireless charging coil L2, and the The DC current or low-frequency AC current flowing through the wireless charging coil L2 on the path is measured; and the voltage detection module in the temperature detector is used to detect the DC voltage or low-frequency AC voltage across the wireless charging coil L2; the temperature calculation in the temperature detector The module is used to receive the data provided by the voltage detection module and the current detection module, and then perform calculation according to the data to determine the temperature corresponding to the wireless charging coil L2.

Exemplarily, the working process of the receiving device PRX may be as follows: the charging coil L1 in the transmitting device PTX is supplied with high-frequency alternating current, and electromagnetic induction and magneto-electric induction phenomena occur with the wireless charging coil L2, and the wireless charging coil L2 generates an induced current immediately. , the induced current is input to the wireless charging circuit through the capacitor C, and the wireless charging circuit rectifies it and provides a DC charging current for the power source to be charged, such as a battery.

When determining the temperature of the wireless charging coil L2, the current detection module contains a DC power source, which can be a DC current source or a DC voltage source, and the specific form is not limited; the A1 end of the current detection module is connected to the wireless charging through the inductor L3 The A4 end of the coil L2, the A2 end of the current detection module is connected to the A3 end of the wireless charging coil L2 through the inductor L4; in this way, when the current detection module is turned on, the current detection module does not need to draw the current in the infinite charging circuit, but directly charges the wireless charging The charging coil L2 provides an independent DC or low-frequency AC path, and the DC power supply in the current detection module provides DC power for this path. The current Is can pass from the A1 end of the current detection module to the A4 end of the wireless charging coil L2 through the inductor L3, and then through The A3 end of the wireless charging coil L2 passes through the inductor L4 to the A2 end of the current detection module to form a complete closed loop; the current detection module measures Is to obtain the current value of the first current.

Then, the voltage detection module measures the first voltage across the wireless charging coil L2. It can be understood that the first voltage is also a DC voltage or a low-frequency AC voltage, and corresponds to a DC current or a low-frequency AC current; exemplarily, the wireless charging coil L2 The first end (A4 end) of the wireless charging coil is connected to one end of the voltage detection module through the filter, and the second end (A3 end) of the wireless charging coil L2 is connected to the other end of the voltage detection module through the filter, and the voltage value of the first voltage is measured. .

The filter can be a filter circuit composed of capacitors and resistors, which can effectively filter out the frequency point of a specific frequency or frequencies other than this frequency point; in this embodiment, the main function of the filter is to reduce the high voltage in the DC voltage as much as possible. frequency AC voltage, and its specific circuit form is not limited.

After the current value of the first current and the voltage value of the first voltage are determined, the voltage detection module and the current detection module transmit data to the temperature calculation module; exemplarily, the temperature detection module first determines the current value of the first current and the voltage value of the first current The voltage value of a voltage determines the DC impedance of the wireless charging coil L2, and then determines the temperature according to the DC impedance and the temperature coefficient of resistance corresponding to the wireless charging coil. The specific method is similar to the method of determining the temperature in the embodiment shown in FIG. 2. Here I won't go into details.

In the technical solution provided by this embodiment, the current detection module in the temperature detector directly provides an independent DC or low-frequency AC path for the wireless charging coil, and obtains the first current on the path and the wireless charging coil corresponding to the first current by obtaining the first current on the path. The first voltage at both ends is used to calculate the temperature corresponding to the wireless charging coil. In this way, the corresponding temperature of the wireless charging coil can be calculated directly according to its own characteristics, and the real state of the wireless charging coil can be obtained in a more timely manner. More accurate and timely monitoring of the temperature of the induction coil inside the terminal, so as to provide timely safety protection measures for it in the future, and improve the safety and reliability of the charging equipment.

FIG. 4 is a schematic flowchart of a temperature detection method for a wireless charging coil provided by an embodiment of the present application. As shown in FIG. 4 , the method includes:

401. Use a wireless charging circuit to rectify the induced current generated by the wireless charging coil and output a DC charging current. Exemplarily, the wireless charging coil in the transmitting device is supplied with high-frequency alternating current, and electromagnetic induction and magnetoelectric induction phenomena occur with the transmitting coil in the receiving device, and an induced current is generated, and the induced current is input to the wireless charging circuit through the capacitor, and the wireless charging circuit The induced current generated by the wireless charging coil in the receiving device is rectified and a DC charging current is provided to the power source to be charged, such as a battery.

402. Acquire a first voltage across both ends of the wireless charging coil. Then, the receiving device provides a DC path or a low-frequency AC path for the wireless charging coil, and then obtains the DC voltage or low-frequency AC voltage at both ends of the wireless charging coil, and measures it to obtain the voltage value of the first voltage.

403. Obtain a first current flowing through the wireless charging coil. Then, the corresponding DC current and low-frequency AC current flowing through the wireless charging coil are obtained. It can be understood that the DC current corresponds to the DC voltage, and the low-frequency AC current corresponds to the low-frequency AC voltage, so as to obtain the current of the first current of the wireless charging coil. value.

404. Determine the DC impedance of the wireless charging coil according to the first voltage and the first current. After the current value of the first current and the voltage value of the first voltage are determined, the DC impedance needs to be calculated according to the values; for example, the receiving device firstly calculates the DC impedance according to the current value of the first current and the voltage value of the first voltage The DC impedance of the wireless charging coil is determined, for example, according to the formula R=V/I, where R is the DC impedance, V is the voltage value of the first voltage, and I is the current value of the first current.

405. Determine the temperature according to the DC impedance. After the DC impedance of the wireless charging coil is determined, the receiving transpose can determine the corresponding temperature according to the stored impedance-temperature correspondence table, wherein the impedance-temperature correspondence table is the DC impedance and temperature drawn according to the resistance temperature coefficient of the wireless charging coil The corresponding table of ; the temperature can also be calculated directly according to the resistance temperature coefficient η of the wireless charging coil. For example, the temperature can be calculated inversely by the formula R=R0*[1+η*(T-25)], where R is the measured temperature. The current DC impedance of , R0 is the DC impedance corresponding to the wireless charging coil at 25 degrees, T is the current temperature value to be determined; it is understandable that T=25+(R-R0)/(R0 can be obtained according to the above formula *η), that is, according to this formula, the DC impedance R of the wireless charging coil determined by the temperature calculation module can be brought in to obtain the temperature corresponding to the wireless charging coil.

Embodiments of the present application further provide an electronic device, including the wireless charging device shown in any of the embodiments in FIG. 3 or FIG. 4 , and a wirelessly charged battery. Optionally, the electronic device is a terminal.

The wireless charging device and the temperature detection method of the wireless charging coil provided by the embodiments of the present application have been described in detail above. The principles and implementations of the present application are described with specific examples. The descriptions of the above embodiments are only used for Help to understand the method of the present application and its core idea; meanwhile, for those of ordinary skill in the art, according to the idea of the present application, there will be changes in the specific implementation and application scope. In summary, the content of this specification It should not be construed as a limitation of this application.

Claims

A wireless charging device, comprising:

The wireless charging circuit is used to rectify the induced current generated by the wireless charging coil and output the DC charging current;

a temperature detector, configured to obtain a first voltage across the two ends of the wireless charging coil, obtain a first current flowing through the wireless charging coil, and determine the wireless charging coil according to the first voltage and the first current The corresponding temperature; wherein, the first voltage is a DC voltage or a low-frequency AC voltage, and the first current is a DC current or a low-frequency AC current.
The device according to claim 1, wherein the temperature detector comprises a temperature calculation module; the temperature calculation module is configured to determine the temperature of the wireless charging coil according to the first voltage and the first current. DC impedance; the temperature is determined according to the DC impedance.
The device according to claim 2, wherein the temperature detection module is specifically configured to: determine the temperature according to the relationship between the DC impedance and the temperature coefficient of resistance of the wireless charging coil.
The device according to any one of claims 1 to 3, wherein the temperature detector further comprises:

a voltage detection module for measuring the first voltage;

A current detection module for generating and measuring the first current.
The device according to claim 4, further comprising a capacitor; a first end of the two ends is connected to a first input end of the wireless charging module through the capacitor, and a first end of the two ends is connected to the first input end of the wireless charging module. The two ends are connected to the second input end of the wireless charging module.
The device according to claim 4 or 5, wherein the current detection module further comprises: a current source for generating the first current.
The device according to any one of claims 4 to 6, further comprising an inductor connected to the current detection module for blocking high-frequency alternating current flowing into the current detection module from the wireless charging coil .
The device according to any one of claims 4 to 7, further comprising a filter, connected to the voltage detection module, for filtering the voltage across the two ends to obtain the first voltage.
The device according to any one of claims 1 to 8, further comprising the wireless charging coil.
A temperature detection method for a wireless charging coil, characterized in that the method comprises:

Use the wireless charging circuit to rectify the induced current generated by the wireless charging coil and output the DC charging current;

acquiring a first voltage at both ends of the wireless charging coil, where the first voltage is a DC voltage or a low-frequency AC voltage;

obtaining a first current flowing through the wireless charging coil, where the first current is a direct current or a low-frequency alternating current;

The temperature corresponding to the wireless charging coil is determined according to the first voltage and the first current.
The method according to claim 10, wherein the determining the temperature corresponding to the wireless charging coil according to the first voltage and the first current comprises:

determining the DC impedance of the wireless charging coil according to the first voltage and the first current;

The temperature is determined from the DC impedance.