Transmitter in wireless power transmission system, and control method and control chip thereof

Abstract

The invention provides a transmitter in a wireless power transmission system, a control method thereof and a control chip, a controllable resonance unit is added between a switch conversion unit and a resonant cavity in the transmitter, and the controllable resonance unit is connected to a power path of the transmitter by controlling the conduction of a switch tube in the controllable resonance unit, so that the power path of the transmitter can be switched on. The voltage is increased through the energy storage and discharge functions of the resonance unit; the controllable resonance unit can also be switched out from the power path of the transmitter by controlling the switching tube in the controllable resonance unit to be switched off, and at the moment, the controllable resonance unit is equivalent to a wire and does not have the function of raising the voltage, so that the requirement that the transmitter can provide output of different power levels is met. Therefore, the transmitter has the advantages of small volume and low cost because the number of transmitter devices is small, and meanwhile, the controllable resonance unit does not need high-frequency switching, so that the control is simple, the switching loss is small, the interference is small, and the efficiency and the performance of the transmitter are improved.

Description

Technical Field

[0001] The present application relates to the field of wireless power transmission, and in particular to a transmitter in a wireless power transmission system, a control method thereof, and a control chip. Background Art

[0002] As technology further develops, wireless power transmission has become an efficient and convenient mechanism for powering or charging battery-based mobile electronic devices such as mobile phones, tablets, digital cameras, MP3 players and / or similar devices. A wireless power transmission system typically includes a transmitter and a receiver.

[0003] See also Figure 1 A typical wireless power transmission system block diagram is shown. The wireless power transmission system includes a transmitter 10 and a receiver 20. The transmitter 10 includes a transmitter circuit 11 and a primary resonant cavity connected in cascade, wherein the primary resonant cavity includes a transmitter coil Lp and a resonant capacitor Cp connected in series. The receiver 20 includes a secondary resonant cavity and a receiver circuit 21 connected in cascade, wherein the secondary resonant cavity 120 includes a receiver coil Ls and a resonant capacitor Cs connected in series.

[0004] In practical applications, the transmitter 10 can be configured in a charging pad, wherein the transmitter coil Lp is placed under the top surface of the charging pad. The receiver 20 can be embedded in a mobile electronic device (such as a mobile phone, tablet computer, digital camera, MP3 player and / or similar device).

[0005] When the receiver 20 is placed within the power output range of the transmitter 10, such as when the mobile electronic device is placed near a charging pad, magnetic coupling is established between the transmitter coil Lp and the receiver coil Ls, such as a coupling coefficient of k, and the output power of the transmitter 10 is transmitted to the receiver 20, that is, wireless power transmission is formed between the transmitter 10 and the receiver 20 to charge the load (such as a rechargeable battery and / or battery pack in the mobile electronic device).

[0006] Please refer to Figure 1 The transmitter 10 further includes a control chip 12 for controlling the transmitter circuit 11 , and the receiver 20 further includes a control chip 22 for controlling the receiver circuit 21 .

[0007] Specifically, wireless charging is carried out under certain standards. The mainstream wireless charging protocol on the market is the Qi protocol. The Qi protocol allows wireless power transmission between transmitters and receivers that meet the protocol, even if they are not dedicated to each other or are not from the same manufacturer.

[0008] The Qi protocol power standard describes that the transmitter must be able to provide the receiver with the power level it needs. The power level depends on the receiver, such as its model, etc.

[0009] In practical applications, this is to meet the needs of receivers with different power levels or the same receiver with different charging powers. Figure 2 The circuit diagram of the conventional transmitter circuit shown includes a cascade-connected BOOST circuit 300, a bridge switch conversion unit 111, and a resonant cavity 112. The BOOST circuit 300 is connected to a voltage source VDC, such as a 9V voltage source.

[0010] When the entire wireless power transmission system is working, when the receiver can support or needs a higher power level for charging, the control chip 12 controls the BOOST circuit 300 to work, increases the 9V voltage source to a higher voltage, and then passes through the subsequent bridge switch conversion unit 111 and the resonant cavity 112 to meet the receiver's high power level energy requirements; when the receiver does not support or does not need a higher power level for charging, the control chip 12 controls the BOOST circuit 300 not to work, making it equivalent to a wire, and the 9V voltage source directly passes through the subsequent bridge switch conversion unit 111 and the resonant cavity 112 to meet the receiver's need for charging at a lower power level.

[0011] From the above description, it can be seen that adding the BOOST circuit 300 to the transmitter undoubtedly increases the size and cost of the transmitter, and the switch tube in the BOOST circuit 300 needs to be switched at high frequency to achieve the boost function, which not only brings a burden to the control chip 12, but also causes switching losses and interference problems caused by high-frequency switching of the switch.

[0012] Therefore, the industry is in urgent need of a low-cost, small-sized, simple-to-control transmitter and its control method or control chip, which can output different power levels according to demand. Summary of the invention

[0013] According to one embodiment, a transmitter in a wireless power transmission system is provided, comprising: a switch conversion unit, comprising at least one switch tube; a controllable resonance unit, comprising a first resonant inductor and a first capacitor switch series branch connected in series, the first capacitor switch series branch comprising a first resonant capacitor and a first control switch connected in series, and the controllable resonance unit is connected between the first end and the second end of the switch conversion unit; a resonant cavity, comprising a second resonant capacitor and a transmitter coil connected in series, and a second capacitor switch series branch connected in parallel at both ends of the second resonant capacitor, the second capacitor switch series branch comprising a third resonant capacitor and a second control switch connected in series, and the resonant cavity is connected between the two ends of the first capacitor switch series branch; wherein the first control switch is configured to be turned off, the second control switch is configured to be closed, and the switch conversion unit is configured to operate at a first switching frequency, so that the transmitter outputs a first power; or the first control switch is configured to be closed, the second control switch is configured to be turned off, and the switch conversion unit is configured to operate at a second switching frequency, so that the transmitter outputs a second power, wherein the second switching frequency is greater than the first switching frequency, and the second power is greater than the first power.

[0014] Furthermore, the transmitter coil is used to couple with a receiver coil in a receiver in a wireless power transmission system.

[0015] Furthermore, the first switching frequency is between 110KHZ and 205KHZ, and the second switching frequency is between 300KHZ and 420KHZ.

[0016] Furthermore, the first resonant inductor is connected between the first end or the second end of the switch conversion unit and the first capacitor switch series branch.

[0017] Furthermore, the first resonant inductor is connected between the first end of the switch conversion unit and the first end of the first capacitor switch series branch; the controllable resonant unit also includes a second resonant inductor, which is connected between the second end of the switch conversion unit and the second end of the first capacitor switch series branch.

[0018] Furthermore, it also includes a control chip for outputting a switch control signal for controlling the switch conversion unit, the first control switch and the second control switch.

[0019] According to another embodiment, a control method for a transmitter in a wireless power transmission system is provided, wherein the transmitter includes a switch conversion unit, a controllable resonant unit, and a resonant cavity connected in cascade, wherein the controllable resonant unit includes a first resonant inductor and a first capacitor switch series branch connected in series, wherein the first capacitor switch series branch includes a first resonant capacitor and a first control switch connected in series, wherein the controllable resonant unit is connected between two output terminals of the switch conversion unit, wherein the resonant cavity includes a second resonant capacitor and a transmitter coil connected in series, and a second capacitor switch series branch connected in parallel at both ends of the second resonant capacitor, wherein the second capacitor switch series branch includes a third resonant capacitor and a second control switch connected in series, wherein the resonant cavity is connected between the first and second output terminals of the switch conversion unit, wherein the controllable resonant unit includes a first resonant inductor and a first capacitor switch series branch connected in series, wherein the first capacitor switch series branch includes a first resonant capacitor and a first control switch connected in series, wherein the controllable resonant unit includes a second resonant capacitor and a transmitter coil connected in series, wherein the second capacitor switch series branch includes a third resonant capacitor and a second control switch connected in series, wherein the resonant cavity is connected between the first and second output terminals of the switch conversion unit, wherein the controllable resonant unit includes a first resonant inductor and a first resonant capacitor connected in series, wherein the first capacitor switch series branch includes a first resonant capacitor and a second control switch connected in series, wherein the first and second resonant inductors are connected in series, wherein the second capacitor switch series branch includes a third resonant capacitor and a second control switch ... A capacitor switch series branch is provided between the two ends, including: S1: the transmitter detects that a receiver is within its power transmission range; S2: the first control switch is controlled to be turned off, the second control switch is controlled to be closed, and the switch conversion unit is controlled to operate at a first switching frequency, so that the transmitter outputs a first power, and the transmitter receives a carrier signal from the receiver through carrier communication; S3: judging whether the receiver supports operating at a second power higher than the first power according to the carrier signal, and if so, controlling the first control switch to be closed and the second control switch to be turned off; S4: controlling the switch conversion unit to operate at a second switching frequency, so that the transmitter outputs a second power, wherein the second switching frequency is greater than the first switching frequency.

[0020] Furthermore, between step S3 and step S4, it also includes: S31: data transmission is performed between the transmitter and the receiver via carrier communication, and the data transmission phase includes at least one of a Ping phase, a configuration phase and a negotiation phase.

[0021] Furthermore, step S3 also includes: controlling all switch tubes in the switch conversion unit to be turned off.

[0022] Furthermore, judging whether the receiver supports operating at a second power higher than the first power according to the carrier signal in step S3 is: judging the model of the receiver according to the carrier signal to judge whether the receiver supports operating at a second power higher than the first power.

[0023] According to another embodiment, a control chip is provided for controlling a first control switch and a second control switch, wherein the first control switch is connected in series with a first resonant capacitor to form a first capacitor switch series branch, the first capacitor switch series branch is connected in series with a first resonant inductor to form a controllable resonant unit, and the controllable resonant unit is connected between a first end and a second end of a switch conversion unit; the second control switch is connected in series with a third resonant capacitor to form a second capacitor switch series branch, the second capacitor switch series branch is connected in parallel with the second resonant capacitor and then connected in series with a transmitter coil to form a resonant cavity, the resonant cavity is connected in parallel with the first capacitor switch series branch, the control chip controls the first control switch to turn off, the second control switch to turn on, and the switch conversion unit to operate at a first switching frequency; or the control chip controls the first control switch to turn on, the second control switch to turn off, and the switch conversion unit to operate at a second switching frequency, wherein the second switching frequency is greater than the first switching frequency.

[0024] Furthermore, the first switching frequency is between 110KHZ and 205KHZ, and the second switching frequency is between 300KHZ and 420KHZ.

[0025] The features and technical advantages of the present disclosure have been summarized quite extensively above so that the detailed description disclosed below may be better understood. Additional features and advantages of the present disclosure will be described below, which constitute the subject matter of the claims of the present disclosure. It will be appreciated by those skilled in the art that the disclosed concepts and specific embodiments may be easily used as a basis for modifying or designing other structures or processes for achieving the same purpose of the present disclosure. It will also be appreciated by those skilled in the art that such equivalent structures do not depart from the spirit and scope of the present disclosure as set forth in the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] For a more complete understanding of the present disclosure and its advantages, reference is now made to the following description in conjunction with the accompanying drawings, in which:

[0027] Figure 1 A schematic diagram of a typical wireless power transmission system block diagram is shown;

[0028] Figure 2 A circuit diagram of an existing transmitter circuit is shown;

[0029] Figure 3 A schematic diagram of a transmitter in a wireless power transmission system according to an embodiment of the present application is shown;

[0030] Figure 4 A schematic diagram of a transmitter in a wireless power transmission system according to another embodiment of the present application is shown;

[0031] Figure 5A schematic diagram of a transmitter in a wireless power transmission system according to another embodiment of the present application is shown;

[0032] Figure 6 A schematic diagram of an output waveform of a switch conversion unit of a transmitter in the prior art is shown;

[0033] Figure 7 A schematic diagram of an output waveform of a switch conversion unit of a transmitter according to an embodiment of the present application is shown;

[0034] Figure 8 A flow chart showing a method for controlling a transmitter in a wireless power transmission system according to an embodiment of the present application is shown.

[0035] Corresponding numerals and symbols in the different figures generally refer to corresponding parts unless otherwise indicated.The figures are drawn to clearly illustrate the relevant aspects of the various embodiments and are not necessarily drawn to scale. DETAILED DESCRIPTION

[0036] The making and use of the currently preferred embodiments are discussed in detail below. However, it should be understood that the present disclosure provides many applicable inventive concepts that can be embodied in various specific contexts. The specific embodiments discussed are only used to illustrate the specific ways to make and use the present invention and do not limit the scope of the present invention.

[0037] In one embodiment of the present application, a transmitter in a wireless power transmission system is provided. Figure 3 The schematic diagram of a transmitter in a wireless power transmission system according to an embodiment of the present application is shown, comprising:

[0038] The switch conversion unit 111 includes at least one switch tube;

[0039] The controllable resonant unit 113 includes a first resonant inductor L1 and a first capacitor switch series branch 1131 connected in series. The first capacitor switch series branch 1131 includes a first resonant capacitor C1 and a first control switch S1 connected in series. The controllable resonant unit 113 is connected between the first end SW1 and the second end SW2 of the switch conversion unit 111.

[0040] The resonant cavity 112 includes a second resonant capacitor Cp and a transmitter coil Lp connected in series, and a second capacitor switch series branch 1121 connected in parallel at both ends of the second resonant capacitor Cp. The second capacitor switch series branch 1121 includes a third resonant capacitor C2 and a second control switch S2 connected in series. The resonant cavity 112 is connected between the two ends of the first capacitor switch series branch 1131;

[0041] The first control switch S1 is configured to be turned off, the second control switch S2 is configured to be closed, and the switch conversion unit 111 is configured to operate at a first switching frequency, so that the transmitter outputs a first power; or

[0042] The first control switch S1 is configured to be closed, the second control switch S2 is configured to be turned off, and the switch conversion unit 111 is configured to operate at a second switching frequency so that the transmitter outputs a second power, wherein the second switching frequency is greater than the first switching frequency, and the second power is greater than the first power.

[0043] In actual implementation, please refer to Figure 1 , the transmitter is used to transmit the output power to the receiver 20. Specifically, the transmitter coil Lp is used to couple with the receiver coil Ls in the receiver in the wireless power transmission system to achieve wireless power transmission.

[0044] As described above, by adding a controllable resonant unit 113 between the switch conversion unit 111 and the resonant cavity 112 in the transmitter, the controllable resonant unit 113 is connected to the power path of the transmitter by controlling the switch tube in the controllable resonant unit 113 to be turned on, and the voltage is raised by the energy storage and release functions of the resonant unit; the controllable resonant unit 113 can also be cut out from the power path of the transmitter by controlling the switch tube in the controllable resonant unit 113 to be turned off. At this time, the controllable resonant unit 113 is equivalent to a wire and does not have the function of raising the voltage, but meets the requirement that the transmitter can provide outputs of different power levels. In this way, the controllable resonant unit 113 replaces the BOOST circuit 300 in the existing transmitter, which meets the same functional requirements as the transmitter in the prior art, and has a small number of components, so it has the advantages of small size and low cost. At the same time, the controllable resonant unit 113 does not require high-frequency switching, so the control is simple, the switching loss is small, and the interference is small, which improves the efficiency and performance of the transmitter.

[0045] Please refer to the actual implementation Figure 3 The switch conversion unit 111 is implemented as a full-bridge switch unit, specifically, including a first switch tube Q1, a second switch tube Q2, a third switch tube Q3 and a fourth switch tube Q4. The first switch tube Q1 and the second switch tube Q2 are connected in series to form a first switch bridge arm, and the third switch tube Q3 and the fourth switch tube Q4 are connected in series to form a second switch bridge arm. The first switch bridge arm is connected in parallel with the second switch bridge arm to receive a DC voltage, such as by connecting a DC voltage source VDC, such as a 9V voltage source, to receive a DC voltage.

[0046] like Figure 3As shown, the common node of the first switch tube Q1 and the second switch tube Q2 is represented as the first common node SW1, and the common node of the third switch tube Q3 and the fourth switch tube Q4 is represented as the second common node SW2. The first common node SW1 forms the first end SW1 of the switch conversion unit 111, and the second common node SW2 forms the second end SW2 of the switch conversion unit 111.

[0047] When the wireless power transmission system is unidirectional, the transmitter is only used to transmit power to the receiver, and the first end SW1 and the second end SW2 of the switch conversion unit 111 also form two output terminals of the switch conversion unit 111. Of course, the wireless power transmission system can also be bidirectional. Figure 3 The transmitter in the embodiment may also be a receiver, which is not limited in this application.

[0048] In practical applications, the switch conversion unit 111 can also be implemented as a half-bridge switch unit, etc. The present application does not limit the specific structure of the switch conversion unit 111. Similarly, the present application does not limit the specific type of the switch tube therein, as long as it can be controlled to be turned on or off. The principle is explained below by taking the switch conversion unit 111 as a full-bridge switch unit as an example.

[0049] Please refer to Figure 3 , the first resonant capacitor C1 and the first control switch S1 are connected in series to form a first capacitor switch series branch 1131, and the first capacitor switch series branch 1131 is connected in series with the first resonant inductor L1 to form a controllable resonant unit 113. Specifically, the first resonant inductor L1 is connected between the first end SW1 of the switch conversion unit 111 and the first end of the first capacitor switch series branch 1131, and the second end of the first capacitor switch series branch 1131 is connected to the second end SW2 of the switch conversion unit 111. The third resonant capacitor C2 is connected in parallel at both ends of the second resonant capacitor Cp and the second control switch S2 is connected in series to form a second capacitor switch series branch 1121. The second capacitor switch series branch 1121 and the second resonant capacitor Cp and the transmitter coil Lp connected in series together form a resonant cavity 112.

[0050] from Figure 3 It can be seen that when the first control switch S1 is controlled to be turned off, the first resonant capacitor C1 is cut out from the power path, which is equivalent to only adding the first resonant inductor L1 in series. Then the first resonant inductor L1, the second resonant capacitor Cp and the transmitter coil Lp are connected in series to form a resonant cavity 112. The first resonant inductor L1 is connected in series in the loop, which is equivalent to a wire with no loss or very small loss. At this time, controlling the second control switch S2 to be closed is equivalent to adding the resonant capacitor in the resonant cavity 112, and controlling the switch conversion unit 111 to work at the first switching frequency, so that the transmitter outputs the first power.

[0051] The first switching frequency here may be between 110KHZ and 205KHZ, and the corresponding transmitter outputs a first power, which may be 5W, 7.5W, etc.

[0052] from Figure 3 It can be seen that when the first control switch S1 is controlled to be closed, the first resonant capacitor C1 and the first resonant inductor L1 are connected in series to form an LC resonant unit, that is, a series inductor and a parallel capacitor are added to the transmitter, which can raise the voltage of the electrical signal output by the switch conversion unit 111, thereby achieving the purpose of boosting and improving the gain of the entire wireless power transmission system. At this time, the second control switch S2 is controlled to be turned off, and only the second resonant capacitor Cp and the transmitter coil Lp form a resonant cavity 112, and the switch conversion unit 111 is controlled to work at the second switching frequency, so that the transmitter outputs the second power.

[0053] The second switching frequency here may be between 300KHZ and 420KHZ, and the corresponding transmitter outputs a second power, which may be 15W or higher.

[0054] For different loads, different first switching frequencies and second switching frequencies may be defined. For example, the first switching frequency may be defined as 128KHZ and the second switching frequency may be defined as 360KHZ.

[0055] When the receiver requires a lower output power, or when the receiver requires a lower charging power, the first control switch S1 can be configured to be turned off, and the controllable resonance unit 113 for raising the voltage is cut out, so that the transmitter outputs a lower voltage, so that the transmitter outputs a lower first power. When the receiver requires a higher output power, or when the receiver requires a higher charging power, the first control switch S1 can be configured to be closed, and the controllable resonance unit 113 for raising the voltage is connected to the power path, so that the transmitter outputs a higher voltage, so that the transmitter outputs a higher second power.

[0056] In actual implementation, when the transmitter detects that a receiver is within its power transmission range, carrier communication is established between the transmitter and the receiver to transmit data between the transmitter and the receiver, and the transmitter and the receiver use a communication protocol to transmit data.

[0057] Specifically, data transmission through a communication protocol usually includes a Ping phase, a configuration phase, a negotiation phase, and a power transfer phase. Generally, in the Ping phase, the transmitter attempts to establish communication with the receiver. In the configuration phase, the receiver sends basic identification and configuration data to the transmitter, and both parties use this data information to create a basic power transfer contract. In the negotiation phase, the transmitter and the receiver establish an extended power transfer contract containing additional settings and restrictions, and the receiver also provides design information to the transmitter. In the power transfer phase, the transmitter transfers power to the receiver.

[0058] In actual implementation, during data transmission, the transmitter determines whether the receiver's load needs to be charged with a lower first power, a higher second power, or first with a lower first power and then with a higher second power based on the carrier signal transmitted from the receiver. It can be seen that the transmitter provided in the present application can flexibly configure its output power according to the needs of the receiver to meet the charging requirements of different loads or different charging stages of the load.

[0059] If it is identified through communication that the load is a load with low charging power such as a watch, the transmitter can be configured to output only the first power mentioned above to charge the load.

[0060] If it is identified through communication that the load requires a higher charging power, the transmitter can be configured to output only the second power mentioned above to charge the load.

[0061] If the load is identified as a mobile phone through communication, the transmitter can generally be configured to output the above-mentioned first power first, and then identify whether the mobile phone supports a higher charging power based on the communication. If so, the transmitter can be configured to increase the output power to the above-mentioned second power.

[0062] In actual implementation, Figure 3 The transmitter further includes a control chip 12, which outputs a switch control signal for controlling the switch conversion unit 111, the first control switch S1, and the second control switch S2. The control chip 12 is configured to turn off the first control switch S1, turn on the second control switch S2, and operate the switch conversion unit 111 at the first switching frequency, so that the transmitter outputs the first power, or to turn on the first control switch S1, turn off the second control switch S2, and operate the switch conversion unit 111 at the second switching frequency, so that the transmitter outputs the second power.

[0063] For actual implementation, see Figure 4 The first resonant inductor L1 can also be connected between the second end SW2 of the switch conversion unit 111 and the first capacitor switch series branch 1131. Its working principle is the same as Figure 3The same is not repeated here.

[0064] For actual implementation, see Figure 5 A schematic diagram of a transmitter in a wireless power transmission system of another embodiment of the present application is shown. The first resonant inductor L1 is connected between the first end SW1 of the switch conversion unit 111 and the first end of the first capacitor switch series branch 1131; the controllable resonant unit 113 also includes a second resonant inductor L2, and the second resonant inductor L2 is connected between the second end SW2 of the switch conversion unit 111 and the second end of the first capacitor switch series branch 1131. In this way, when the first control switch S1 is configured to be closed, the controllable resonant unit 113 forms an LLC resonant unit. When the first control switch S1 is configured to be turned off, the first resonant inductor L1 and the second resonant inductor L2 are both connected in series in the resonant cavity 112. Its working principle is the same as Figure 3 The same is not repeated here.

[0065] When the receiver is embedded in the mobile phone, at the beginning of charging, which can also be called the first charging stage, the charging power of the mobile phone is relatively low, such as 5W, 7.5W, etc. At this time, the transmitter can be configured to output the above-mentioned lower first power. In order to achieve the lower first power, the transmitter can be configured to output a lower first output voltage, such as between 5V and 9V. At this time, the controllable resonance unit 113 does not need to raise the voltage, so the first control switch S1 is configured to be turned off, the second control switch S2 is configured to be closed, and at the same time the switch conversion unit 111 is configured to operate at a lower first switching frequency, so that the transmitter outputs a lower first power. In the first charging stage, the transmitter and the receiver communicate via a carrier signal. At any stage of the communication, if the transmitter detects that the charging power of the mobile phone can be a higher second power, such as 15W or higher, the transmitter can be configured to output a higher second output voltage, such as between 5V and 14V. At this time, the controllable resonance unit 113 is required to raise the voltage, so the first control switch S1 is configured to be closed, the second control switch S2 is configured to be turned off, and at the same time the switch conversion unit 111 is configured to operate at the second switching frequency, so that the transmitter outputs a higher second power.

[0066] As can be seen from the above description, the transmitter can be adjusted according to the receiver to achieve a better charging strategy. The first control switch S1 and the second control switch S2 are only closed or turned off when switching the output power. Therefore, no matter it works at a higher output power or a lower output power, the loss of the transmitter is mainly the high-frequency switching loss of the switch tube in the switch conversion unit 111, so the loss of the transmitter is low.

[0067] In actual implementation, the control chip 12 controls the on and off of the first switch tube Q1 , the second switch tube Q2 , the third switch tube Q3 and the fourth switch tube Q4 to output an AC signal between the first common node SW1 and the second common node SW2 .

[0068] For a transmitter without a controllable resonance unit 113, it can be understood that a square wave signal is output between the first common node SW1 and the second common node SW2. Figure 6 The schematic diagram of the output waveform of the switch conversion unit of the transmitter in the prior art shows that a typical square wave signal is present between the first common node SW1 and the second common node SW2 , and the peak is relatively large, so the EMI is relatively poor.

[0069] If a transmitter with a controllable resonant unit 113 is added, due to the energy storage and release of LC or LLC, a sinusoidal wave signal is output between the first common node SW1 and the second common node SW2. Figure 7 The output waveform diagram of the switch conversion unit of the transmitter of one embodiment of the present application is shown, and it can be seen that the first common node SW1 and the second common node SW2 are approximately sinusoidal signals, so EMI can be greatly improved. This is very important for applications with strict EMI requirements, such as automobiles.

[0070] The present application also provides a control method for a transmitter in a wireless power transmission system, wherein the transmitter is Figure 3 , Figure 4 or Figure 5 The transmitter in the embodiment includes a switch conversion unit 111, a controllable resonant unit 113 and a resonant cavity 112 connected in cascade, the controllable resonant unit 113 includes a first resonant inductor L1 and a first capacitor switch series branch 1131 connected in series, the first capacitor switch series branch 1131 includes a first resonant capacitor C1 and a first control switch S1 connected in series, the controllable resonant unit 113 is connected between two output terminals (SW1, SW2) of the switch conversion unit 111, the resonant cavity 112 includes a second resonant capacitor Cp and a transmitter coil Lp connected in series, and a second capacitor switch series branch 1121 connected in parallel at both ends of the second resonant capacitor Cp, the second capacitor switch series branch 1121 includes a third resonant capacitor C2 and a second control switch S2 connected in series, and the resonant cavity 112 is connected between the two ends of the first capacitor switch series branch 1131. Please refer to Figure 8 The flowchart of the control method of the transmitter in the wireless power transmission system of one embodiment of the present application shown includes:

[0071] S1: The transmitter detects that a receiver is within its power transmission range;

[0072] S2: Control the first control switch S1 to be turned off, the second control switch S2 to be turned on, and control the switch conversion unit 111 to operate at the first switching frequency, so that the transmitter outputs the first power, and the transmitter receives the carrier signal from the receiver through carrier communication;

[0073] S3: judging whether the receiver supports operating at a second power higher than the first power according to the carrier signal, and if so, controlling the first control switch S1 to close and the second control switch S2 to turn off;

[0074] S4: Control the switch conversion unit 111 to operate at a second switching frequency so that the transmitter outputs a second power, wherein the second switching frequency is greater than the first switching frequency.

[0075] It can be seen that in actual implementation, when the receiver is embedded in a mobile electronic device, such as a mobile phone, when the mobile electronic device is placed near the charging pad, that is, the transmitter detects that a receiver is placed within its power transmission range, controls the first control switch S1 to be turned off, the second control switch S2 to be closed, and controls the switch conversion unit 111 to operate at the first switching frequency, so that the transmitter outputs the first power, and at the same time the transmitter and the receiver communicate via a carrier signal, then the transmitter can determine whether the receiver supports operating at a second power higher than the first power according to the carrier signal, if the first control switch S1 is closed and the second control switch S2 is turned off, then the switch conversion unit 111 is controlled to operate at the second switching frequency, so that the transmitter outputs the second power, wherein the second switching frequency is greater than the first switching frequency. The transmitter can adjust a better charging strategy according to the receiver, and the transmitter has low loss.

[0076] In actual implementation, step S3 also includes: controlling all switch tubes in the switch conversion unit 111 to turn off. That is, before the transmitter enters the mode of outputting a higher second power, the switch conversion unit 111 is first controlled to switch out of the mode of outputting a lower first power, that is, the switch conversion unit 111 is controlled not to work, so that the transmitter output power is zero, and then enters the mode of outputting a higher second power.

[0077] In actual implementation, before the transmitter enters the power transmission stage of outputting the first power and the second power, data transmission is performed between the transmitter and the receiver through carrier communication, and the data transmission stage includes at least one of the above-mentioned Ping stage, configuration stage and negotiation stage. The function of each stage is the same as above, and will not be repeated here. In actual implementation, between step S3 and step S4, it also includes: S31: Data transmission is performed between the transmitter and the receiver through carrier communication, and the data transmission stage includes at least one of the Ping stage, configuration stage and negotiation stage.

[0078] In actual implementation, judging whether the receiver supports working at a second power higher than the first power according to the carrier signal in step S3 may be judged by the carrier signal in at least one of the above-mentioned Ping stage, configuration stage, negotiation stage and power transmission stage. In actual implementation, judging whether the receiver supports working at a second power higher than the first power according to the carrier signal in step S3 is: judging the model of the receiver according to the carrier signal to judge whether the receiver supports working at a second power higher than the first power. That is, according to the definition of each stage, it is better to judge in the configuration stage.

[0079] In one embodiment of the present application, a control chip is also provided. Figure 3 , Figure 4 or Figure 5 The control chip 12 is used to control the first control switch S1 and the second control switch S2, wherein the first control switch S1 is connected in series with the first resonant capacitor C1 to form a first capacitor switch series branch 1131, the first capacitor switch series branch 1131 is connected in series with the first resonant inductor L1 to form a controllable resonant unit 113, and the controllable resonant unit 113 is connected between the first end SW1 and the second end SW2 of a switch conversion unit 111; the second control switch S2 is connected in series with the third resonant capacitor C2 to form a second capacitor switch series branch 1121, the second capacitor switch series branch 1121 is connected in parallel with the second resonant capacitor Cp and then connected in series with the transmitter coil Lp to form a resonant cavity 112, and the resonant cavity 112 is connected in parallel with the first capacitor switch series branch 1131.

[0080] Among them, the control chip 12 controls the first control switch S1 to be turned off, the second control switch S2 to be closed, and the switch conversion unit 111 to operate at a first switching frequency; or the control chip 12 controls the first control switch S1 to be closed, the second control switch S2 to be turned off, and the switch conversion unit 111 to operate at a second switching frequency, wherein the second switching frequency is greater than the first switching frequency.

[0081] In a specific embodiment, the first switching frequency is between 110KHZ and 205KHZ, and the second switching frequency is between 300KHZ and 420KHZ.

[0082] Its principles and advantages are the same as those of the transmitter in the above-mentioned wireless power transmission system, and will not be repeated here.

[0083] In a preferred embodiment, the receiver adapted to the above-mentioned transmitter is embedded in an iPhone mobile phone, and the wireless charging protocol between the transmitter and the receiver is the MPP protocol in the latest QI2.0 protocol.

[0084] Although the embodiments of the present disclosure and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the disclosure as defined by the appended claims.

[0085] In addition, the scope of the present application is not intended to be limited to the specific embodiments of the processes, machines, manufactures, material compositions, devices, methods, and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of this disclosure, processes, machines, manufactures, material compositions, means, methods, or steps that perform substantially the same functions currently exist or will later be developed or achieve substantially the same results as the corresponding embodiments described herein that can be used according to this disclosure. Therefore, the appended claims are intended to include such processes, machines, manufactures, material compositions, devices, methods, or steps within their scope.

Claims

1. A transmitter in a wireless power transmission system, characterized in that: include: The switch conversion unit includes at least one switch tube; A controllable resonant unit, comprising a first resonant inductor and a first capacitor switch series branch connected in series, wherein the first capacitor switch series branch comprises a first resonant capacitor and a first control switch connected in series, and the controllable resonant unit is connected between the first end and the second end of the switch conversion unit; A resonant cavity, comprising a second resonant capacitor and a transmitter coil connected in series, and a second capacitor switch series branch connected in parallel at both ends of the second resonant capacitor, wherein the second capacitor switch series branch comprises a third resonant capacitor and a second control switch connected in series, and the resonant cavity is connected between both ends of the first capacitor switch series branch; in The first control switch is configured to be turned off, the second control switch is configured to be closed, and the switch conversion unit is configured to operate at a first switching frequency, so that the transmitter outputs a first power; or The first control switch is configured to be closed, the second control switch is configured to be turned off, and the switch conversion unit is configured to operate at a second switching frequency, so that the transmitter outputs a second power, wherein the second switching frequency is greater than the first switching frequency, and the second power is greater than the first power.

2. The transmitter in the wireless power transmission system according to claim 1, characterized in that: The transmitter coil is used to couple with a receiver coil in a receiver in a wireless power transfer system.

3. The transmitter in the wireless power transmission system according to claim 1, characterized in that: The first switching frequency is between 110KHZ and 205KHZ, and the second switching frequency is between 300KHZ and 420KHZ.

4. The transmitter in the wireless power transmission system according to claim 1, characterized in that: The first resonant inductor is connected between the first end or the second end of the switch conversion unit and the first capacitor switch series branch.

5. The transmitter in the wireless power transmission system according to claim 1, characterized in that: The first resonant inductor is connected between the first end of the switch conversion unit and the first end of the first capacitor switch series branch; The controllable resonance unit further includes a second resonant inductor connected between the second end of the switch conversion unit and the second end of the first capacitor switch series branch.

6. The transmitter in the wireless power transmission system according to claim 1, characterized in that: It also includes a control chip for outputting a switch control signal for controlling the switch conversion unit, the first control switch and the second control switch.

7. A control method for a transmitter in a wireless power transmission system, characterized in that: The transmitter includes a switch conversion unit, a controllable resonant unit and a resonant cavity connected in cascade, the controllable resonant unit includes a first resonant inductor and a first capacitor switch series branch connected in series, the first capacitor switch series branch includes a first resonant capacitor and a first control switch connected in series, the controllable resonant unit is connected between two output terminals of the switch conversion unit, the resonant cavity includes a second resonant capacitor and a transmitter coil connected in series, and a second capacitor switch series branch connected in parallel at both ends of the second resonant capacitor, the second capacitor switch series branch includes a third resonant capacitor and a second control switch connected in series, the resonant cavity is connected between both ends of the first capacitor switch series branch, and includes: S1: The transmitter detects that a receiver is within its power transmission range; S2: Control the first control switch to be turned off, the second control switch to be turned on, and control the switch conversion unit to operate at a first switching frequency, so that the transmitter outputs a first power, and the transmitter receives a carrier signal from a receiver through carrier communication; S3: judging whether the receiver supports operating at a second power higher than the first power according to the carrier signal, and if so, controlling the first control switch to be closed and the second control switch to be turned off; S4: Control the switch conversion unit to operate at a second switching frequency so that the transmitter outputs a second power, wherein the second switching frequency is greater than the first switching frequency.

8. The control method of the transmitter in the wireless power transmission system according to claim 7, characterized in that: Also included between step S3 and step S4: S31: The transmitter and the receiver perform data transmission via carrier communication, and the data transmission phase includes at least one of a Ping phase, a configuration phase, and a negotiation phase.

9. The control method of the transmitter in the wireless power transmission system according to claim 7, characterized in that: Step S3 also includes: controlling all switch tubes in the switch conversion unit to turn off.

10. The control method of the transmitter in the wireless power transmission system according to claim 7, characterized in that: Determining whether the receiver supports operating at a second power higher than the first power according to the carrier signal in step S3 is: determining the model of the receiver according to the carrier signal to determine whether the receiver supports operating at a second power higher than the first power.

11. A control chip, used to control a first control switch and a second control switch, wherein the first control switch is connected in series with a first resonant capacitor to form a first capacitor switch series branch, the first capacitor switch series branch is connected in series with a first resonant inductor to form a controllable resonant unit, the controllable resonant unit is connected between a first end and a second end of a switch conversion unit; the second control switch is connected in series with a third resonant capacitor to form a second capacitor switch series branch, the second capacitor switch series branch is connected in parallel with a second resonant capacitor and then connected in series with a transmitter coil to form a resonant cavity, the resonant cavity is connected in parallel with the first capacitor switch series branch, characterized in that: The control chip controls the first control switch to be turned off, the second control switch to be turned on, and the switch conversion unit to operate at a first switching frequency; or The control chip controls the first control switch to be closed, the second control switch to be turned off, and the switch conversion unit to operate at a second switching frequency, wherein the second switching frequency is greater than the first switching frequency.

12. The control chip according to claim 11, characterized in that: The first switching frequency is between 110KHZ and 205KHZ, and the second switching frequency is between 300KHZ and 420KHZ.

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