WO2021114813A1

WO2021114813A1 - High-frequency wireless charging efficiency and loss testing system and method

Info

Publication number: WO2021114813A1
Application number: PCT/CN2020/117347
Authority: WO
Inventors: 许校嘉; 张政; 胡新跃; 申屠嘉辉
Original assignee: 横店集团东磁股份有限公司
Priority date: 2019-12-11
Filing date: 2020-09-24
Publication date: 2021-06-17
Also published as: CN111366782A; CN111366782B

Abstract

A high-frequency wireless charging efficiency and loss testing system and method, the testing system comprising a signal generator (1), a power amplifier (2), a test circuit (3), a test load (5), an oscilloscope (4), and a controller (6), the signal generator (1) being connected to the power amplifier (2), the signal generator (1) being used for producing high-frequency signals required for testing, an output end of the power amplifier (2) being connected to an input end of the test circuit (3), a wireless charging transmission coil (P1) and a wireless charging receiving coil (P2) being connected between the input end and an output end of the test circuit (3), the power amplifier (2) being used for converting the high-frequency signals produced by the signal generator (1) into a high-frequency power source, and the signal generator (1) and the oscilloscope (4) both being connected to the controller (6). By means of using magnetic sheet coils made of different materials and calculating the charging conversion efficiency of said materials, more suitable wireless charging materials can be selected; by means of precisely testing wireless charging efficiency and loss at high frequencies, a method is provided for testing high-frequency wireless charging performance, providing a foundation for improving wireless charging efficiency.

Description

High-frequency wireless charging efficiency and loss testing system and method

Technical field

The invention relates to the field of wireless charging, in particular to a high-frequency wireless charging efficiency and loss testing system and method.

Background technique

Electronic devices have been developing in the direction of miniaturization, thinning and high efficiency. People use electronic devices more and more frequently. It is particularly important to charge electronic devices faster and more efficiently. Wireless charging technology can make the charging of electronic devices more Convenient and fast, and the efficiency of wireless charging is the main factor affecting wireless charging. Therefore, accurately measuring the efficiency and loss of wireless charging, especially the efficiency and loss of wireless charging under high-frequency conditions, can quantitatively evaluate the advantages and disadvantages of wireless charging, so as to select high-performance wireless charging materials for use in electronic products.

For example, a "wireless charging system and its control method" disclosed in Chinese patent documents, its announcement number CN104716747B, and its application number on December 8, 2017, include impedance matching of the antenna to make the resonant frequency of the wireless charging system The point falls within an operating frequency range; to track the best frequency point, first transmit the test signal at a set transmission frequency, and calculate its transmission efficiency; determine whether the transmission efficiency meets the requirements, if not, repeat the above "Procedure" Optimal frequency point tracking, first transmit the test signal at a set transmission frequency and calculate its transmission efficiency" step until the transmission efficiency meets the requirements; if the transmission efficiency meets the requirements, set the transmission frequency to the best frequency point ; Use the optimal frequency point as the operating frequency of the system for charging; wherein, when tracking the optimal frequency point, one of the following two steps is used to determine whether the transmission efficiency meets the requirements: Step 1: Determine the efficiency change and Whether the ratio of frequency change is less than or equal to zero; if the ratio is greater than zero, add a frequency value to the originally set transmission frequency, then reset the transmission frequency, transmit the test signal, calculate the transmission efficiency of the test signal, and judge again Whether the ratio of the efficiency change to the frequency change is less than or equal to zero; when the ratio is less than or equal to zero, the transmitting frequency is set as the optimal frequency point; Step 2: Determine whether the ratio of the efficiency change to the frequency change is greater than or equal to zero ; If the ratio is less than zero, the frequency value is decremented from the originally set transmitting frequency, then the transmitting frequency is reset, the test signal is transmitted, the transmission efficiency of the test signal is calculated, and the ratio of the efficiency change to the frequency change is re-judged Whether it is greater than or equal to zero; when the ratio is greater than or equal to zero, the transmitting frequency is set as the optimal frequency point. By selecting the optimal frequency point, the charging efficiency of wireless charging is improved, but without considering the charging material, the improved charging efficiency is limited by the material, and the charging efficiency cannot be effectively improved.

Summary of the invention

The present invention is to overcome the problem of low charging efficiency caused by material limitation of wireless charging in the prior art, and provides a high-frequency wireless charging efficiency and loss testing system and method, which can accurately test the wireless charging efficiency and loss under high frequency. The high-frequency wireless charging performance test provides a method.

In order to achieve the above objectives, the present invention adopts the following technical solutions: a high-frequency wireless charging efficiency and loss test system, including a signal generator, a power amplifier, a test circuit test load, an oscilloscope and a controller, the signal generator and the The input end of the power amplifier is connected, the signal generator is used to generate a high-frequency signal required for testing, the output end of the power amplifier is connected to the input end of the test circuit, and the test load is connected to the output end of the test circuit A wireless charging transmitting coil and a wireless charging receiving coil are connected between the input terminal and the output terminal of the test circuit, and the power amplifier is used to convert the high-frequency signal generated by the signal generator into a high-frequency power source. The oscilloscope is connected to the test resistor, and the oscilloscope is used to display the waveforms of the current and voltage applied to the test load. The signal generator and the oscilloscope are both connected to the controller. The high-frequency signal used in the test is generated by the signal generator, which is amplified by the power amplifier to form a high-frequency power source, which is connected to the test circuit through a wire and used as a charging power source for the test circuit. The voltage and current waveforms are displayed by an oscilloscope to adjust the test circuit. The phase difference between the input current and the output current and the input voltage and the output voltage reduces the test error, the system is simple and convenient, and the cost is low.

Preferably, the test circuit includes an ammeter A1, an ammeter A2, a voltmeter V1, a voltmeter V2, a resonant capacitor C1, and a resonant capacitor C2. The wireless charging transmitting coil and the wireless charging receiving coil are respectively equipped with magnetic sheets. The coil P1 and the coil P2 with the magnetic sheet, the first end of the ammeter A1 is connected to the first end of the high-frequency power supply, and the second end of the ammeter A1 is connected to one end of the coil P1 with the magnetic sheet Connected, the second end of the high-frequency power supply is connected to the first end of the resonant capacitor C1, the second end of the resonant capacitor C1 is connected to the other end of the coil P1 with a magnetic sheet, and the voltmeter V1 is connected in parallel At both ends of the coil P1 with a magnetic sheet, the voltmeter V2 is connected in parallel to both ends of the coil P2 with a magnetic sheet, and the first end of the current meter A2 is connected to one end of the coil P2 with a magnetic sheet , The second end of the ammeter A2 is connected to the first end of the test load, the first end of the resonant capacitor C2 is connected to the other end of the coil P2 with a magnetic sheet, and the second end of the resonant capacitor C2 is connected to the The second end of the test load is connected. The current of the test circuit is detected by the ammeter A1 and the ammeter A2, and the voltage of the test circuit is detected by the voltmeter V1 and the voltmeter V2, which is convenient for the subsequent calculation of the wireless charging efficiency of the test circuit. The coil is a magnetic sheet coil. The magnetic sheet coils of different materials are tested to compare their wireless charging conversion efficiency and loss. Through loss analysis, the reasons that affect the wireless charging conversion efficiency are selected. Suitable wireless charging materials are selected to improve wireless charging efficiency and provide high-frequency wireless charging performance testing.了方法。 The method. The material and shape of the magnetic sheet can be arbitrarily replaced.

The present invention also provides a high-frequency wireless charging efficiency and loss test method, which includes the following steps: S01: Start the signal generator to generate a voltage signal of the required frequency for the test, and adjust the power amplifier to output a stable high-frequency power voltage; S02: Select and adjust the resonant capacitor C1 and the resonant capacitor C2 so that the phase difference between the voltage and current on the coil P1 with the magnetic sheet and the coil P2 with the magnetic sheet is 0°; S03: When calculating the test band Magnetic induction intensity on the coil P2 with magnetic sheet; S04: Calculate the conversion efficiency of wireless charging.

Preferably, in the step S03, the calculation formula of the magnetic induction intensity during the test is:

Where N ₁ is the number of turns of the coil P1, A _e is the effective cross-sectional area of the magnetic sheet, f is the test frequency, u _out is the output voltage measured by the voltmeter V2, and B is the magnetic induction intensity. The magnetic induction intensity during the test is calculated, and the magnetic induction intensity is included in the analysis when the wireless charging material is selected to prevent excessive magnetic induction from causing pollution or damage to the human body, and to ensure that the selected wireless charging material is a safe and pollution-free material.

Preferably, in the step S04, the conversion efficiency of the wireless charging is obtained by calculating the input power and the output power, and the calculation formula of the input power is:

Wherein, P _in is the input power P1 of the coil, f is the test frequency, u _in is measured by the voltmeter V1 input voltage, i _in a current meter A1 input of the current measured;

The calculation formula of output power is:

Among them, P _out is the output power of the coil P2, u _out is the output terminal voltage measured by the voltmeter V2, and i _out is the output terminal current measured by the ammeter A2;

The conversion efficiency of the magnetic sheet is:

Among them, μ is the conversion efficiency of wireless charging. Calculate the input power and output power of the test circuit through the voltage and current, and calculate the wireless charging conversion efficiency of the magnetic sheet through the input power and output power.

Preferably, the factors that determine the conversion efficiency of the magnetic sheet include hysteresis loss, eddy current loss and copper wire loss, where the calculation formula of eddy current loss is:

Among them, σ is the electrical conductivity of the magnetic sheet, μ is the magnetic permeability of the magnetic sheet, d is the width of the magnetic sheet, f is the test frequency, and P _cl is the eddy current loss power. Through the calculation of eddy current loss, the material itself and the width of the material are selected, and the wireless charging material with smaller eddy current loss is selected.

Preferably, the resistance R _Cu of the copper wire is measured by a multimeter, and the calculation formula of the copper wire loss is:

Among them, P _Cul is the power loss of the copper wire used in the coil P1 and the coil P1, f is the test frequency, i _in is the current at the input of the coil P1 measured by the ammeter A1, and i _out is the output of the coil P2 measured by the ammeter A2 The terminal current, R _Cu is the resistance of the copper wire. Through the calculation of copper wire loss, the influence of the wires of the test circuit on the wireless charging efficiency is eliminated, and the test error is reduced.

Preferably, the calculation formula of the hysteresis loss is:

P _hl = (P _in -P _out )-P _cl -P _Cul (7)

Wherein, P _hl hysteresis loss of power, P _in is the input power winding P1, P _out is the output power winding P2, P _Cul copper wire power loss.

Therefore, the present invention has the following beneficial effects: (1) The wireless charging efficiency test system is constructed by a simple circuit, which is simple and convenient, and saves costs; (2) The magnetic sheet coil made of different materials is used to calculate the charging conversion of the material Efficiency, select more suitable wireless charging materials; (3) By accurately testing the wireless charging efficiency and loss under high frequency, it provides a method for high-frequency wireless charging performance testing and provides a basis for improving wireless charging efficiency.

Description of the drawings

Fig. 1 is a schematic diagram of the structure of the test system of the first embodiment.

Fig. 2 is a schematic diagram of the circuit connection of the test circuit of the first embodiment.

In the figure: 1. Signal generator, 2. Power amplifier, 3. Test circuit. 4. Oscilloscope, 5. Test load, 6. Controller.

Detailed ways

The present invention will be further described below in conjunction with the drawings and specific embodiments.

The first embodiment, a high-frequency wireless charging efficiency and loss test system, as shown in Figure 1, includes a signal generator 1, a power amplifier 2, a test circuit 3, a test load 5, an oscilloscope 4 and a controller, and the signal generator 1 Connect with the input end of the power amplifier 2. The signal generator 1 is used to generate the high-frequency signal required for testing, the output end of the power amplifier 2 is connected with the test circuit 3, and the power amplifier 2 is used to transfer the high-frequency signal generated by the signal generator 1. The signal is converted into a high-frequency power source, the test circuit 3 is connected to an oscilloscope 4, and the oscilloscope 4 is used to display the current waveform and size and the voltage waveform and size on the test circuit 3. A coil P1 with a magnetic sheet and a coil P2 with a magnetic sheet are connected between the input terminal and the output terminal of the test circuit, which respectively serve as a wireless charging transmitting coil and a wireless charging receiving coil.

As shown in Figure 2, the test circuit 3 includes ammeter A1, ammeter A2, voltmeter V1, voltmeter V2, resonant capacitor C1, and resonant capacitor C2. The first end of the ammeter A1 and the first end of the high-frequency power supply Connected, the second end of the ammeter A1 is connected to one end of the coil P1 with a magnetic sheet, the second end of the high-frequency power supply is connected to the first end of the resonant capacitor C1, and the second end of the resonant capacitor C1 is connected to the second end of the resonant capacitor C1. The other end of the coil P1 of the sheet is connected, the voltmeter V1 is connected in parallel with the two ends of the coil P1 with the magnetic sheet, the voltmeter V2 is connected in parallel with both ends of the coil P2 with the magnetic sheet, and the first end of the ammeter A2 is connected with the One end of the coil P2 with a magnetic sheet is connected, the second end of the ammeter A2 is connected with the first end of the test load 5, and the first end of the resonance capacitor C2 is connected with the other end of the coil P2 with a magnetic sheet. The second end is connected to the second end of the test load 5. The material and shape of the magnetic sheet can be replaced arbitrarily.

A high-frequency wireless charging efficiency and loss test method, including the following steps: S01: Start the signal generator 1 to generate a voltage signal of the required frequency for the test, and adjust the power amplifier 2 to output a stable high-frequency power voltage; S02: Select and adjust the resonant capacitor C1 and the resonant capacitor C2 so that the phase difference between the voltage and current on the coil P1 with the magnetic sheet and the coil P2 with the magnetic sheet is 0°.

S03: Calculate the magnetic induction intensity during the test; the calculation formula of the magnetic induction intensity during the test is:

Where N ₁ is the number of turns of the coil P1, A _e is the effective cross-sectional area of the magnetic sheet, f is the test frequency, u _out is the output voltage measured by the voltmeter V2, and B is the magnetic induction intensity.

S04: Calculate the conversion efficiency of the magnetic sheet; the conversion efficiency of the magnetic sheet is obtained by calculating the input power and the output power. The calculation formula of the input power is:

Wherein, P _in is the input power P1 of the coil, f is the test frequency, u _in is measured by the voltmeter V1 input voltage, i _in a current meter A1 measured input current; output power calculation formula is:

Among them, P _out is the output power of the coil P2, u _out is the output voltage measured by the voltmeter V2, and i _out is the output current measured by the ammeter A2; the conversion efficiency of the magnetic sheet is:

Among them, μ is the conversion efficiency of the magnetic sheet.

The factors that determine the conversion efficiency of the magnetic sheet include hysteresis loss, eddy current loss and copper wire loss. Among them, the calculation formula of eddy current loss is:

Among them, σ is the electrical conductivity of the magnetic sheet, μ is the magnetic permeability of the magnetic sheet, d is the width of the magnetic sheet, f is the test frequency, P _cl is the eddy current loss power, and the resistance of the copper wire R _{Cu is} measured by a multimeter. The calculation formula of line loss is:

Among them, P _Cul is the power loss of the copper wire used by the coil P1 and the coil P1, f is the test frequency, i _in is the input current measured by the ammeter A1, i _out is the output current measured by the ammeter A2, R _Cu Is the resistance of the copper wire, and the calculation formula of hysteresis loss is:

P _hl = (P _in -P _out )-P _cl -P _Cul (7)

Among them, P _Cul is the power loss of the copper wire.

Embodiment 2. In this embodiment, as shown in Table 1, the signal generator 1 is adjusted to output a signal with a frequency of 1 MHz, which is amplified by the power amplifier 2 and used as the power supply for the test circuit 3. The magnification of the amplifier 2 controls the input power of the test circuit 3. The magnetic coil made of nanocrystalline MS700 is selected for testing, and the input power is adjusted to 1W. After testing, the output power is calculated to be 0.909W, and its conversion efficiency is 90.90%. The loss is 0.091, of which, the copper wire loss is 0.0345, the hysteresis loss is 0.0188, and the eddy current loss is 0.0376; the input power is adjusted to 13W, and the output power is calculated to be 11.47W after testing, the conversion efficiency is 88.23%, and the total loss is 1.53. Among them, the copper wire loss is 0.4355, the hysteresis loss is 0.6399, and the eddy current loss is 0.4545.

Table 1 Test results of several test materials

Table 1

The third embodiment is to adjust the signal generator 1 to output a signal with a frequency of 1MHZ, select a magnetic coil made of manganese-zinc ferrite FS600B for testing, adjust the input power to 1W, and calculate the output power to be 0.938W after testing. The conversion efficiency is 93.8%, and the total loss is 0.062. Among them, the copper wire loss is 0.0319, the hysteresis loss is 0.0195, and the eddy current loss is 0.0105; the adjusted input power is 13W, and the output power is calculated to be 11.92W after testing, and its conversion efficiency is 91.69 %, the total loss is 1.08, of which, the copper wire loss is 0.4173, the hysteresis loss is 0.5264, and the eddy current loss is 0.1362.

The fourth embodiment is to adjust the signal generator 1 to output a signal with a frequency of 1MHZ, select a magnetic coil made of nickel-zinc ferrite FS700 for testing, adjust the input power to 1W, and calculate the output power to be 0.922W after testing. The conversion efficiency is 92.2%, and the total loss is 0.078. Among them, the copper wire loss is 0.0334, the hysteresis loss is 0.0330, and the eddy current loss is 0.0115; the adjusted input power is 13W, and the output power is calculated to be 11.48W after testing, and its conversion efficiency is 88.31 %, the total loss is 1.52, of which, the copper wire loss is 0.4223, the hysteresis loss is 0.9541, and the eddy current loss is 0.1435.

Through embodiment two, embodiment three and embodiment four, it can be seen that under the premise of the same test frequency and the same input power, the conversion efficiency of the magnetic coil made of manganese-zinc ferrite FS600B is significantly higher. Therefore, through this The invention can select more suitable wireless charging materials, and at the same time, provides a method for high-frequency wireless charging performance testing, and also provides a basis for improving the efficiency of wireless charging.

The above-mentioned embodiment is only a preferred solution of the present invention, and does not limit the present invention in any form. There are other variations and modifications under the premise of not exceeding the technical solution described in the claims.

Claims

A high-frequency wireless charging efficiency and loss test system, which is characterized in that it includes

A signal generator, a power amplifier, a test circuit, a test load, an oscilloscope, and a controller, the signal generator is connected to the input end of the power amplifier, and the signal generator is used to generate high-frequency signals required for the test. The output end of the power amplifier is connected to the input end of the test circuit, the test load is connected to the output end of the test circuit, and a wireless charging transmitting coil and a wireless charging receiving coil are connected between the input end and the output end of the test circuit, The power amplifier is used to convert the high-frequency signal generated by the signal generator into a high-frequency power source, the oscilloscope is connected to a test resistor, and the oscilloscope is used to display the waveforms of current and voltage applied to the test load, Both the signal generator and the oscilloscope are connected to the controller.
The high-frequency wireless charging efficiency and loss test system according to claim 1, wherein the test circuit includes an ammeter A1, an ammeter A2, a voltmeter V1, a voltmeter V2, a resonant capacitor C1, and a resonant capacitor C2, the wireless charging transmitting coil and the wireless charging receiving coil are respectively a coil P1 with a magnetic sheet and a coil P2 with a magnetic sheet, and the first end of the ammeter A1 is connected to the first end of the high-frequency power supply , The second end of the ammeter A1 is connected to one end of the coil P1 with a magnetic sheet, the second end of the high-frequency power source is connected to the first end of the resonant capacitor C1, and the second end of the resonant capacitor C1 The end is connected to the other end of the coil P1 with a magnetic sheet, the voltmeter V1 is connected in parallel with both ends of the coil P1 with a magnetic sheet, and the voltmeter V2 is connected in parallel with both ends of the coil P2 with a magnetic sheet, The first end of the ammeter A2 is connected to one end of the coil P2 with a magnetic sheet, the second end of the ammeter A2 is connected to the first end of the test load, and the first end of the resonant capacitor C2 is connected to the first end of the test load. The other end of the coil P2 of the magnetic sheet is connected, and the second end of the resonant capacitor C2 is connected to the second end of the test load.
A high-frequency wireless charging efficiency and loss testing method, using a high-frequency wireless charging efficiency and loss testing system as claimed in claim 1 or 2, includes the following steps:

S01: Start the signal generator to generate a voltage signal of the frequency required for the test, and adjust the power amplifier to output a stable high-frequency power voltage;

S02: Select and adjust the resonant capacitor C1 and the resonant capacitor C2 so that the phase difference between the voltage and current on the coil P1 with the magnetic sheet and the coil P2 with the magnetic sheet is 0°;

S03: Calculate the magnetic induction intensity on the coil P2 with a magnetic sheet during the test;

S04: Calculate the conversion efficiency of wireless charging.
A high-frequency wireless charging efficiency and loss testing method according to claim 3, characterized in that, in the step S03, the calculation formula of the magnetic induction intensity on the coil P2 with the magnetic sheet during the test is:

Where N 1 is the number of turns of the coil P1, A e is the effective cross-sectional area of the magnetic sheet, f is the test frequency, u out is the output voltage measured by the voltmeter V2, and B is the magnetic induction intensity.
A high-frequency wireless charging efficiency and loss testing method according to claim 3, characterized in that, in the step S04, the conversion efficiency of the wireless charging is obtained by calculating the input power and the output power, and the calculation formula of the input power for:

Wherein, P in is the input power P1 of the coil, f is the test frequency, u in is measured by the voltmeter V1 input voltage, i in a current meter A1 input of the current measured;

The calculation formula of output power is:

Among them, P out is the output power of the coil P2, u out is the output terminal voltage measured by the voltmeter V2, and i out is the output terminal current measured by the ammeter A2;

The conversion efficiency of the magnetic sheet is:

Among them, μ is the conversion efficiency of wireless charging.
A high-frequency wireless charging efficiency and loss testing method according to claim 3, wherein the factors determining the conversion efficiency of the wireless charging include hysteresis loss, eddy current loss and copper wire loss, wherein the calculation of eddy current loss The formula is:

Among them, σ is the electrical conductivity of the magnetic sheet, μ is the magnetic permeability of the magnetic sheet, d is the width of the magnetic sheet, f is the test frequency, and P cl is the eddy current loss power.
A high-frequency wireless charging efficiency and loss testing method according to claim 6, wherein the calculation formula of copper wire loss is:

Among them, P Cul is the power loss of the copper wire used in the coil P1 and the coil P1, f is the test frequency, i in is the current at the input of the coil P1 measured by the ammeter A1, and i out is the output of the coil P2 measured by the ammeter A2 The terminal current, R Cu is the resistance of the copper wire.
A high-frequency wireless charging efficiency and loss testing method according to claim 6, wherein the calculation formula of hysteresis loss is:

P hl = (P in -P out )-P cl -P Cul (7)

Wherein, P hl hysteresis loss of power, P in is the input power winding P1, P out is the output power winding P2, P Cul copper wire power loss.