Wireless energy transmission circuit, charging device and charging system

Abstract

The invention relates to a wireless energy transmission circuit, a charging device and a charging system, and the wireless energy transmission circuit comprises a multi-level inverter circuit which is provided with a first input end and a first output end, the first input end is electrically connected with a DC power supply, and the first output end is electrically connected with the DC power supply; the output module is used for outputting an alternating-current output voltage comprising a plurality of voltage components according to a direct-current power supply voltage of the direct-current power supply; wherein the frequencies of different voltage components are different; the resonance circuit is provided with a second input end and a second output end, the second input end is electrically connected with the first output end, the second output end is electrically connected with a transmitting circuit, and the resonance circuit is used for enabling the transmitting circuit to transmit energy corresponding to the voltage components with different frequencies according to the alternating current output voltage; and the transmitting circuit is used for transmitting the energy corresponding to each voltage component in a wireless transmission mode.

Description

Technical Field

[0001] This disclosure relates to the field of electronic circuit technology, and in particular to a wireless power transmission circuit, charging device and charging system. Background Technology

[0002] With the development of power electronics technology, its application in the control field is becoming increasingly widespread. In many applications involving the control aspects of power electronics, various circuits are needed to process the power supply voltage to provide the appropriate voltage to the powered equipment.

[0003] Wireless power transfer, as an application of power electronics technology, can be used in the field of wireless charging to achieve wireless charging. Summary of the Invention

[0004] This disclosure provides a wireless power transfer circuit, a charging device, and a charging system.

[0005] A first aspect of this disclosure provides a wireless power transmission circuit, characterized in that it comprises: a multi-level inverter circuit having a first input terminal and a first output terminal, the first input terminal being electrically connected to a DC power supply, for outputting an AC output voltage containing at least one voltage component according to the DC supply voltage of the DC power supply; wherein the different voltage components have different frequencies; wherein the maximum number of voltage components is greater than 2; a resonant circuit having a second input terminal and a second output terminal, the second input terminal being electrically connected to the first output terminal, the second output terminal being electrically connected to a transmitting circuit, for obtaining current components corresponding to the voltage components according to the AC output voltage, such that the transmitting circuit transmits energy corresponding to the current components at different frequencies; the transmitting circuit is used to transmit the energy corresponding to each of the current components wirelessly.

[0006] In one embodiment, the system further includes a controller electrically connected to the multilevel inverter circuit for controlling the operating state of the multilevel inverter circuit, thereby causing the multilevel inverter circuit to output the AC output voltage.

[0007] In one embodiment, the number of voltage components contained in the AC output voltage of multilevel inverter circuits with different circuit structures is different; or, the number of voltage components contained in the AC output voltage of multilevel inverter circuits with different circuit structures is the same; or, the number of voltage components contained in the AC output voltage of the same multilevel inverter circuit is different.

[0008] In one embodiment, the multilevel inverter circuit includes: a single-phase multilevel inverter circuit, used to output the AC output voltage according to the single-phase DC power output by the DC power supply.

[0009] In one embodiment, the voltage components have their own duty cycles, and the effective values ​​of the different voltage components are determined based on the respective duty cycles of each voltage component.

[0010] In one embodiment, the controller has multiple control modes; under different control modes, the number of voltage components included in the AC output voltage is different, and / or, at least some of the voltage components have different frequencies.

[0011] In one embodiment, the multilevel inverter circuit includes: a plurality of controlled switches, each connected to the controller; wherein the multilevel inverter circuit outputs voltage components of different frequencies, and the controlled switches have different switching states.

[0012] In one embodiment, the multi-level inverter circuit includes a single-phase three-level inverter circuit; the single-phase three-level inverter circuit includes: a first capacitor; a second capacitor connected in series with the first capacitor between the positive and negative terminals of the DC power supply; a first controlled switch with its drain connected to the positive terminal of the DC power supply and its gate connected to the controller; a second controlled switch with its drain connected between the first capacitor and the second capacitor and its gate connected to the controller; a third controlled switch with its source connected to the source of the second controlled switch, its drain connected to the source of the first controlled switch, and its gate connected to the controller; a fourth controlled switch with its drain connected to the source of the first controlled switch, its source connected to the negative terminal, and its gate connected to the controller; a fifth controlled switch with its drain connected to the positive terminal and its gate connected to the controller; and a sixth controlled switch with its drain connected between the first capacitor and the second capacitor and its gate connected to the controller. The seventh controlled switch has its source connected to the source of the sixth controlled switch, its drain connected to the source of the fifth controlled switch, and its gate connected to the controller; the eighth controlled switch has its drain connected to the source of the fifth controlled switch, its source connected to the negative terminal, and its gate connected to the controller; wherein, the first controlled switch, the second controlled switch, the third controlled switch, and the fourth controlled switch form the first bridge arm, and the fifth controlled switch, the sixth controlled switch, the seventh controlled switch, and the eighth controlled switch form the second bridge arm; the connection point of the first capacitor and the second capacitor serves as the DC side midpoint; the connection point of the source of the first controlled switch, the drain of the third controlled switch, and the drain of the fourth controlled switch serves as the positive terminal of the first output terminal; the connection point of the source of the fifth controlled switch, the drain of the seventh controlled switch, and the drain of the eighth controlled switch serves as the negative terminal of the first output terminal.

[0013] In one embodiment, the output voltage includes: a first voltage component with a first frequency; the second controlled switch, the third controlled switch, and the fifth controlled switch are turned on; the second controlled switch, the third controlled switch, and the eighth controlled switch are turned on; wherein the fifth controlled switch and the eighth controlled switch are turned on alternately, and the remaining controlled switches are turned off; the on-frequency of the second controlled switch, the third controlled switch, the fifth controlled switch, and the eighth controlled switch is the first frequency.

[0014] In one embodiment, the output voltage includes: a second voltage component with a frequency of a second frequency; the first controlled switch is turned on, the sixth controlled switch and the seventh controlled switch are turned on, and the remaining controlled switches are turned off; wherein, the on-frequency of the first controlled switch, the sixth controlled switch and the seventh controlled switch is the second frequency.

[0015] In one embodiment, the output voltage includes: a third voltage component with a third frequency; the fourth controlled switch is turned on, the sixth controlled switch and the seventh controlled switch are turned on, and the remaining controlled switches are turned off; wherein the turning frequency of the fourth controlled switch, the sixth controlled switch and the seventh controlled switch is the third frequency.

[0016] In one embodiment, the transmitting circuit includes a transmitting coil; the resonant circuit includes: a first inductor, one end of which is connected to the first output terminal; a third capacitor connected in series between the first inductor and the transmitting coil; and a fourth capacitor connected in parallel with the first inductor; wherein, the first equivalent impedance of the first inductor and the fourth capacitor resonates in series with the third capacitor and the transmitting coil, and the transmitting coil resonates with the first receiving circuit at a first frequency; the first equivalent impedance is an inductive impedance; the first inductor and the fourth capacitor resonate in parallel, the first inductor, the third capacitor, and the transmitting coil resonate in parallel, and the transmitting coil resonates with the second receiving circuit at a second frequency; the second equivalent impedance of the first inductor and the fourth capacitor resonates in series with the third capacitor and the transmitting coil, and the transmitting coil resonates with the first receiving circuit at a third frequency; the second equivalent impedance is a capacitive impedance.

[0017] A second aspect of this disclosure provides a charging device, including: the wireless power transmission circuit described in any of the above embodiments.

[0018] A third aspect of this disclosure provides a charging system, comprising: a wireless power transmission circuit as described in any of the above embodiments; a plurality of powered devices, each powered device having its own receiving circuit, each receiving circuit being wirelessly connected to and resonating with a transmitting circuit in the wireless power transmission circuit; wherein the transmitting circuit resonates at different frequencies with different receiving circuits; the receiving circuit is used to receive energy transmitted by the transmitting circuit; the energy is used to power the powered devices.

[0019] The technical solutions provided by the embodiments of this disclosure may include the following beneficial effects:

[0020] The solution of this disclosure uses a multi-level inverter circuit to output an output voltage containing at least one voltage component of different frequencies, and a resonant circuit to obtain the current component corresponding to each voltage component based on the output voltage, enabling the transmitting circuit to transmit the energy corresponding to the current components of different frequencies. This achieves multi-band energy transmission, expands the number of output voltage components of different frequencies, allows for differentiation and isolation of voltage components corresponding to different frequencies, ensures that different frequency voltage components do not affect each other, and allows for individual adjustment of each frequency voltage component. The current component changes with the corresponding voltage component; adjusting the voltage component also adjusts the corresponding current component, thereby enabling energy transmission to a larger number of energy receiving devices and improving the user experience.

[0021] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description

[0022] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure.

[0023] Figure 1 This is a schematic diagram of a wireless power transfer circuit according to an exemplary embodiment;

[0024] Figure 2 This is a schematic diagram illustrating one state of a bridge arm according to an exemplary embodiment;

[0025] Figure 3 This is a schematic diagram illustrating another state of the bridge arm according to an exemplary embodiment;

[0026] Figure 4 This is a schematic diagram illustrating another state of the bridge arm according to an exemplary embodiment;

[0027] Figure 5 This is a schematic diagram illustrating the operating state of a multilevel inverter circuit according to an exemplary embodiment;

[0028] Figure 6 This is a schematic diagram illustrating the operating state of another multilevel inverter circuit according to an exemplary embodiment;

[0029] Figure 7 This is a waveform diagram of a first voltage component according to an exemplary embodiment;

[0030] Figure 8 This is a schematic diagram illustrating the operating state of another multilevel inverter circuit according to an exemplary embodiment;

[0031] Figure 9 This is a schematic diagram illustrating the operating state of another multilevel inverter circuit according to an exemplary embodiment;

[0032] Figure 10 This is a waveform diagram of an output voltage according to an exemplary embodiment;

[0033] Figure 11 This is a schematic diagram of the output voltage of another multilevel inverter circuit according to an exemplary embodiment;

[0034] Figure 12 This is a schematic diagram illustrating a charging system according to an exemplary embodiment;

[0035] Figure 13 This is an equivalent circuit diagram illustrating a first voltage component of a first frequency output according to an exemplary embodiment;

[0036] Figure 14 This is an equivalent circuit diagram illustrating a second voltage component at a second frequency when outputting according to an exemplary embodiment;

[0037] Figure 15 This is an equivalent circuit diagram illustrating a third voltage component at a third frequency, according to an exemplary embodiment.

[0038] Figure 16 This is an equivalent circuit diagram of a resonant circuit, a transmitting circuit, and a receiving circuit according to an exemplary embodiment;

[0039] Figure 17 This is a block diagram illustrating a terminal device according to an exemplary embodiment. Detailed Implementation

[0040] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. Rather, they are merely examples of apparatuses consistent with some aspects of this disclosure as detailed in the appended claims.

[0041] refer to Figure 1 The diagram shows a wireless power transfer circuit, which includes:

[0042] The multilevel inverter circuit 1 has a first input terminal and a first output terminal. The first input terminal is electrically connected to a DC power supply and is used to output an AC output voltage containing at least one voltage component according to the DC supply voltage of the DC power supply; wherein the different voltage components have different frequencies.

[0043] The resonant circuit 2 has a second input terminal and a second output terminal. The second input terminal is electrically connected to the first output terminal, and the second output terminal is electrically connected to the transmitting circuit 3. It is used to obtain the current component corresponding to the voltage component based on the AC output voltage, so that the transmitting circuit can emit the energy corresponding to the current component of different frequencies.

[0044] Transmitting circuit 3 is used to transmit the energy corresponding to each current component wirelessly.

[0045] The multilevel inverter circuit 1 can be a two-level inverter circuit, a three-level inverter circuit, a four-level inverter circuit, a five-level inverter circuit, a seven-level inverter circuit, a nine-level inverter circuit, or any other circuit capable of inverting DC power to output multiple voltage levels. The specific structure of the multilevel inverter circuit 1 and the number of output voltage levels are not limited here; they can be determined according to the application requirements.

[0046] The circuit structure of multi-level inverter circuit 1 is not limited and can be determined according to the application requirements. Inverter circuits with the same number of voltage levels may have different structures. For example, even though they are all three-level inverter circuits, different three-level inverter circuits may have different circuit structures.

[0047] For example, the multi-level inverter circuit 1 is a single-phase multi-level inverter circuit, and the output of the multi-level inverter circuit 1 is single-phase electricity.

[0048] The input terminal of the multilevel inverter circuit 1 is electrically connected to the DC power supply, that is, connected to the positive and negative terminals of the DC power supply. The input terminal of the multilevel inverter circuit 1 is designated as the first input terminal, and the output terminal of the multilevel inverter circuit 1 is designated as the first output terminal.

[0049] A DC power supply can include a DC voltage source, the DC supply voltage of which can be determined according to usage requirements. A DC voltage source is a DC-side input voltage source that provides a supply voltage of u. dc .

[0050] The multilevel inverter circuit 1 can convert the DC voltage provided by the DC voltage source into at least one AC voltage of different levels. The voltage output by the multilevel inverter circuit 1 is denoted as the AC output voltage. The AC output voltage includes at least one voltage component of different frequencies. When there are multiple voltage components, the multiple voltage components are superimposed to form the AC output voltage.

[0051] For example, each voltage component has its own frequency, and the frequency of each voltage classification can be determined according to the usage requirements. Different voltage components can have different frequencies, that is, they can be distinguished from each other.

[0052] Each voltage component has its own frequency, amplitude, and effective value, which can be determined based on the duty cycle. Different voltage components have their own duty cycles, and therefore their own effective values.

[0053] For example, different voltage components have different levels, that is, different voltage values ​​and different voltage waveforms.

[0054] For example, the number of output levels of the multilevel inverter circuit 1 is greater than or equal to the number of voltage components.

[0055] For example, a multilevel inverter circuit 1 may include multiple controlled switches. If the switching states of the controlled switches are different, the voltage components in the output voltage of the multilevel inverter circuit 1 will be different. For example, the number, frequency, and amplitude of the voltage components may be different.

[0056] For example, the AC output voltage of the multilevel inverter circuit 1 includes a maximum number of voltage components greater than 2, which increases the number of voltage components and reduces the limitation on the number of voltage components, thereby enabling it to charge more devices with different charging frequencies.

[0057] The resonant circuit 2 has an input terminal and an output terminal. The input terminal of the resonant circuit 2 is referred to as the second input terminal, and the output terminal of the resonant circuit 2 is referred to as the second output terminal. The second input terminal is electrically connected to the first output terminal of the multi-level inverter circuit 1, and the second output terminal is electrically connected to the transmitting circuit 3. The resonant circuit 2 is used to obtain the current component corresponding to each voltage component based on the AC output voltage, so that the transmitting circuit emits the energy corresponding to the current component of different frequencies.

[0058] The structure of the resonant circuit 2 can be determined according to the usage requirements. It can obtain the current component corresponding to each voltage component based on the AC output voltage, so that the transmitting circuit 3 can transmit the energy corresponding to the current components of different frequencies output by the resonant circuit 2.

[0059] For example, in alternating current, the frequency of the voltage component is the same as the frequency of the current component obtained by passing the voltage component through a resonant circuit.

[0060] For example, the resonant circuit 2 can be a resonant filter network.

[0061] For example, the resonant circuit 2 may include at least one capacitor, at least one inductor, and / or at least one resistor, etc.

[0062] For example, the resonant circuit 2 may include an n-order Foster network, each order of which includes a capacitor and an inductor connected in parallel. A Foster network can also be called an LC network. n series-connected Foster networks form an n-order Foster network. N is a positive integer.

[0063] For example, the Foster network may also include capacitors connected in series with parallel capacitors and inductors.

[0064] The number of resonant points of resonant circuit 2 is n, and resonant circuit 2 enables transmitting circuit 3 to wirelessly transmit energy corresponding to n current components.

[0065] For example, n is greater than or equal to the number of voltage components output by the multilevel inverter circuit 1.

[0066] Transmitting circuit 3 is used to transmit the energy corresponding to each current component wirelessly.

[0067] The structure of the transmitting circuit 3 is not limited and may include a transmitting coil. The two ends of the transmitting coil are connected to the second output terminal of the resonant circuit 2.

[0068] The multi-level inverter circuit outputs a voltage with at least one voltage component of different frequencies. A resonant circuit can then determine the corresponding current component based on the output voltage, enabling the transmitting circuit to emit energy corresponding to the current components of different frequencies. This allows for multi-band energy transmission, expands the number of output voltage components of different frequencies, distinguishes and isolates the voltage components at each frequency, ensures that different frequency voltage components do not affect each other, and allows for individual adjustment of each frequency voltage component. The current component changes with the corresponding voltage component; adjusting the voltage component also adjusts the corresponding current component, thus enabling energy transmission to a larger number of energy receiving devices and improving the user experience.

[0069] In one embodiment, it also includes:

[0070] The controller is electrically connected to the multilevel inverter circuit 1 and is used to control the working state of the multilevel inverter circuit 1 so that the multilevel inverter circuit 1 outputs AC output voltage.

[0071] Figure 1 The controller is not shown in the figure. The type, model, size and other parameters of the controller are not limited. It is sufficient that it has the function of controlling the working state of the multi-level inverter circuit 1.

[0072] For example, the controller can output a control signal to control the switching state of each controlled switch in the multilevel inverter circuit 1, the switching state including on and off.

[0073] The multilevel inverter circuit 1 includes multiple controlled switches. The operating state of the multilevel inverter circuit 1 can be determined according to the switching state of each controlled switch. Different switching states of the controlled switches result in different operating states of the multilevel inverter circuit 1 and different output voltage components.

[0074] The controller adjusts the operating state of the multilevel inverter circuit 1 by controlling the switching state of each controlled switch in the multilevel inverter circuit 1, thereby controlling the multilevel inverter circuit 1 to output an AC output voltage containing multiple voltage components of different frequencies.

[0075] In one embodiment, the number of voltage components in the AC output voltage of a multilevel inverter circuit 1 with different circuit structures varies.

[0076] The circuit structure of the multilevel inverter circuit 1 can be determined according to the usage requirements. When the circuit structure of the multilevel inverter circuit 1 is different, the output AC voltage may be different. For example, the number of voltage components contained in the AC output voltage may be different, and the frequency of the voltage components may be different.

[0077] In one embodiment, multilevel inverter circuits with different circuit structures have the same number of voltage components in their output AC output voltage.

[0078] In one embodiment, the number of voltage components in the output AC output voltage of the same multilevel inverter circuit may differ.

[0079] The voltage components in the AC output voltage can be adjusted using the same multilevel inverter circuit. For example, by adjusting the state of each controlled switch in the multilevel inverter circuit, the quantity and / or frequency of the voltage components in the AC output voltage can be changed. This eliminates the need to replace the multilevel inverter circuit, allowing for adjustment of the AC output voltage without changing the multilevel inverter circuit itself.

[0080] In one embodiment, the multilevel inverter circuit includes:

[0081] A single-phase multi-level inverter circuit is used to output AC output voltage based on the single-phase DC power output from a DC power supply.

[0082] In one embodiment, the voltage components have their own duty cycles, and the effective values ​​of different voltage components are determined based on the respective duty cycles of each voltage component.

[0083] In one embodiment, the controller has multiple control modes;

[0084] Under different control modes, the number of voltage components contained in the AC output voltage is different, and / or, at least some of the voltage components have different frequencies.

[0085] The number of control modes can be determined according to requirements or preset at the factory. In each control mode, the number of voltage components in the AC output voltage, the frequency of at least some of the voltage components, and the duty cycle of each voltage component can be different.

[0086] For example, the controller has two control modes: control mode 1 and control mode 2. In control mode 1, the AC output voltage contains two voltage components, including the frequency f. x The voltage component and frequency are f y The voltage component. In control mode 2, the AC output voltage contains 3 voltage components, including frequency f. x The voltage component with frequency f z The voltage component and frequency are f k The voltage component.

[0087] The control mode can be adjusted according to the user's operation.

[0088] By adjusting the control mode, the AC output voltage of the multi-level inverter circuit 1 can be regulated, allowing for the adjustment of individual voltage components. This, in turn, regulates the current component output by the resonant circuit 2, thereby altering the energy of the current component emitted by the transmitting circuit. This allows for charging of varying numbers of receiving devices and at different charging frequencies, improving the versatility of the wireless power transmission circuit and enhancing the user experience.

[0089] In one embodiment, the multilevel inverter circuit 1 includes:

[0090] Multiple controlled switches are connected to the controller; the multi-level inverter circuit outputs voltage components of different frequencies, and the switching states of the controlled switches are different.

[0091] Different multilevel inverter circuits 1 may have different circuit structures, and each multilevel inverter circuit 1 has its own unique circuit structure. The number of controlled switches in the multilevel inverter circuit 1 can be determined based on the circuit structure and the number of output voltage levels. Inverter circuits with different numbers of output voltage levels may have different numbers of controlled switches and different circuit structures.

[0092] For example, the structure of a three-level inverter circuit and the number of controlled switches it includes, the structure of a five-level inverter circuit and the number of controlled switches it includes, and the structure of a seven-level inverter circuit and the number of controlled switches it includes may all be different.

[0093] In one embodiment, reference Figure 1 The multi-level inverter circuit 1 includes a single-phase three-level inverter circuit, which includes two bridge arms. Each bridge arm includes four controlled switches. The controlled switches may include metal-oxide-semiconductor field-effect transistors (MOSFETs), i.e., MOS transistors, or transistors or other controlled switches.

[0094] Each bridge arm serves as a polarity output terminal in the first output terminal of the multilevel inverter circuit 1, and can be either a positive or negative output terminal. For example, one bridge arm can serve as the positive output terminal in the first output terminal, and the other bridge arm can serve as the negative output terminal in the first output terminal.

[0095] For example, refer to Figure 1 The single-phase three-level inverter circuit includes:

[0096] First capacitor C a ;

[0097] Second capacitor C b , with the first capacitor C a It is connected in series between the positive and negative terminals of the DC power supply;

[0098] First controlled switch S a1 The first controlled switch S a1 The drain of the circuit is connected to the positive terminal of the DC power supply, and the first controlled switch S a1 The gate is connected to the controller;

[0099] Second controlled switch S a2 The second controlled switch S a2 The drain is connected to the first capacitor C a Second capacitor C b Between, the second controlled switch S a2 The gate is connected to the controller;

[0100] Third controlled switch S a3 The third controlled switch S a3 The source and the second controlled switch S a2 The source connection, the third controlled switch S a3 The drain of the first controlled switch S a1 The source connection, the third controlled switch S a3 The gate is connected to the controller;

[0101] Fourth controlled switch S a4 The fourth controlled switch S a4 The drain of the first controlled switch S a1 The source connection, the fourth controlled switch S a4 The source terminal is connected to the negative terminal of the DC power supply, and the fourth controlled switch S a4 The gate is connected to the controller;

[0102] Fifth controlled switch S b1 The fifth controlled switch S b1 The drain of the circuit is connected to the positive terminal of the DC power supply, and the fifth controlled switch S... b1The gate is connected to the controller;

[0103] Sixth controlled switch S b2 The sixth controlled switch S b2 The drain is connected to the first capacitor C a Second capacitor C b Between, the sixth controlled switch S b2 The gate is connected to the controller;

[0104] Seventh controlled switch S b3 The seventh controlled switch S b3 The source and the sixth controlled switch S b2 The source connection, the seventh controlled switch S b3 The drain and the fifth controlled switch S b1 The source connection, the seventh controlled switch S b3 The gate is connected to the controller;

[0105] Eighth controlled switch S b4 The eighth controlled switch S b4 The drain and the fifth controlled switch S b1 The source connection, the eighth controlled switch S b4 The source terminal is connected to the negative terminal of the DC power supply, and the eighth controlled switch S b4 The gate is connected to the controller.

[0106] First controlled switch S a1 Second controlled switch S a2 Third controlled switch S a3 and the fourth controlled switch S a4 Forming the first bridge arm, the fifth controlled switch S b1 The sixth controlled switch S b2 The seventh controlled switch S b3 and the eighth controlled switch S b4 Forming the second bridge arm; the first capacitor C a Second capacitor C b The connection point is taken as the midpoint of the DC side.

[0107] First controlled switch S a1 The source, the third controlled switch S a3 The drain and the fourth controlled switch S a4 The connection point of the drain terminal serves as the positive terminal of the first output terminal; the fifth controlled switch S b1 The source, the seventh controlled switch S b3 The drain and the eighth controlled switch S b4 The connection point of the drain terminal serves as the negative terminal of the first output terminal.

[0108] First capacitor C aThe voltage across the two terminals can be denoted as u1, and the second capacitor C b The voltage across the two ends can be denoted as u2, the midpoint of the DC side can be denoted as O, and the first controlled switch S a1 First capacitor C a and the fifth controlled switch S b1 The point where these three devices are connected to the positive terminal of the DC power supply can be denoted as point P, and the fourth controlled switch S... a4 Second capacitor C b and the eighth controlled switch S b4 The point where these three devices are connected to the negative terminal of the DC power supply can be denoted as point N.

[0109] Point P can represent the positive terminal of the DC power supply on the DC side, and point N can represent the negative terminal of the DC power supply on the DC side.

[0110] First capacitor C a Second capacitor C b This represents two discrete capacitors on the DC side; for example, the first capacitor C... a Second capacitor C b The two capacitors have the same capacitance value, which allows the midpoint potential to be balanced, i.e., u1 = u2 = 0.5u. dc .

[0111] For example, the single-phase three-level inverter circuit is a T-type single-phase three-level inverter circuit, which includes two bridge arms, namely the first bridge arm and the second bridge arm. The first bridge arm can be represented by bridge arm a, and the second bridge arm can be represented by bridge arm b.

[0112] Each bridge arm includes four controlled switches, which can be controlled using S. xj (x = a, b; j = 1, 2, 3, 4) is used to represent this, where x represents the bridge arm and j represents the sequence number of the switch on the bridge arm. When S xj A value of "1" indicates the switch is on, and a value of "0" indicates the controlled switch is off. Each pair of bridge arms has two sets of switching transistors S... x1 and S x3 Complementary conduction, S x2 and S x4 Complementary conduction is used to avoid the influence of current direction on the controlled switch drive during commutation. Furthermore, S x1 With S x4 They also cannot be simultaneously switched on to prevent the same bridge arm from being directly connected, which could lead to a short circuit.

[0113] Figure 1 u in in i represents the output voltage of multi-level inverter circuit 1. in These represent the output currents of the multi-level inverter circuit 1, i and i. o It is a neutral current.

[0114] For example, each arm of the multilevel inverter circuit 1 has three different operating modes. In different operating modes, the output voltage of the multilevel inverter circuit 1 is different, and the switching state of the controlled switches in the arm is different. Taking one arm a as an example for illustration.

[0115] refer to Figure 2 This is a schematic diagram of one state of the bridge arm, which can be denoted as state P. In this state, the first controlled switch S... a1 When the circuit is open, all other controlled switches in bridge arm a are closed. Taking point O as a reference point, when the voltages of the two capacitors on the DC side are balanced, the output voltage u of bridge arm a is... a =u1=0.5u dc .

[0116] refer to Figure 3 This is a schematic diagram of another state of the bridge arm, which can be denoted as state O. In this state, the second controlled switch S... a2 and the third controlled switch S a3 When the circuit is open, all other controlled switches in bridge arm a are closed. When the voltages of the two capacitors on the DC side are balanced, the output voltage of bridge arm a is 0.

[0117] refer to Figure 4 This is a schematic diagram of another state of the bridge arm, which can be denoted as state N. In this state, the fourth controlled switch S... a4 When the circuit is open, all other controlled switches in bridge arm a are closed. Taking point O as a reference point, when the voltages of the two capacitors on the DC side are balanced, the output voltage of bridge arm a is u. a =-u2=-0.5u dc .

[0118] Similarly, bridge arm b also has three different operating modes, including P state, O state, and N state. In the P state, the fifth controlled switch S b1 When the circuit is open, all other controlled switches in bridge arm b are closed. Taking point O as a reference point, when the voltages of the two capacitors on the DC side are balanced, the output voltage u of bridge arm b is... b =u1=0.5u dc .

[0119] In state O, the sixth controlled switch S b2 and the seventh controlled switch S b3 When the circuit is open, all other controlled switches in bridge arm b are closed. When the voltages of the two capacitors on the DC side are balanced, the output voltage of bridge arm b is 0.

[0120] In state N, the eighth controlled switch S b4When the circuit is open, all other controlled switches in bridge arm b are closed. Taking point O as a reference point, when the voltages of the two capacitors on the DC side are balanced, the output voltage of bridge arm b is u. b =-u2=-0.5u dc .

[0121] Referring to Table 1 below, the corresponding relationships between the switching states of each controlled switch, the output voltage of each bridge arm, and the output current in the multi-level inverter circuit 1 are listed.

[0122] Table 1

[0123]

[0124] Among them, u x (x = a, b) represent the voltage u output by a single bridge arm, respectively. a and u b .

[0125] Define the state function S of the controlled switch x As shown in formula (1):

[0126]

[0127] The output voltage U of a single bridge arm in multilevel inverter circuit 1 x This can be expressed as formula (2):

[0128]

[0129] Therefore, the output voltage U of the multi-level inverter circuit 1 can be obtained. in The expression for is shown in formula (3):

[0130]

[0131] Since each bridge arm has three switching states: P, O, and N, there are a total of 9 switching states for the controlled switches in the multilevel inverter circuit 1 when it is working, as shown in Table 2:

[0132] Table 2

[0133]

[0134] Table 2 shows the operating states of the multilevel inverter circuit 1, including the switching states shown in Table 2, and also shows the output voltage u of the multilevel inverter circuit 1. in and output current.

[0135] Of the nine states shown in Table 2, the other controlled switches in the multilevel inverter circuit 1 are in the off state by default.

[0136] In one embodiment, the output voltage of the multilevel inverter circuit 1 includes a first voltage component with a frequency of a first frequency.

[0137] Second controlled switch S a2 Third controlled switch S a3 and the fifth controlled switch S b1 Conduction;

[0138] Second controlled switch S a2 Third controlled switch S a3 and the eighth controlled switch S b4 Conduction;

[0139] Among them, the fifth controlled switch S b1 and the eighth controlled switch S b4 Alternate conduction occurs while the remaining controlled switches are disconnected;

[0140] Second controlled switch S a2 Third controlled switch S a3 Fifth controlled switch S b1 and the eighth controlled switch S b4 The conduction frequency is the first frequency.

[0141] refer to Figure 5 This is a schematic diagram of the working state of a multi-level inverter circuit 1, showing the second controlled switch S in the first bridge arm. a2 Third controlled switch S a3 The eighth controlled switch S in the second bridge arm b4 The circuit is turned on, and the conduction frequency of the three controlled switches is the first frequency. The multi-level inverter circuit 1 is in the ON operating state, and the first sub-voltage component of the multi-level inverter circuit 1 is u. in1_1 =0.5u dc .

[0142] For example, the remaining controlled switches are turned off.

[0143] refer to Figure 6 This is a schematic diagram of the operating state of another multi-level inverter circuit 1, showing the second controlled switch S in the first bridge arm. a2 Third controlled switch S a3 The fifth controlled switch S in the second bridge arm b1 The circuit is turned on, and the conduction frequency of the three controlled switches is the first frequency. The multi-level inverter circuit 1 is in the OP (operational) state, and the second sub-voltage component of the multi-level inverter circuit 1 is u. in1_2 =-0.5u dc .

[0144] For example, the remaining controlled switches are turned off.

[0145] For example, the fifth controlled switch Sb1 The conduction time and the eighth controlled switch S b4 There is a preset time difference between the conduction times.

[0146] refer to Figure 7 This is a waveform diagram of a first voltage component. Figure 7 The diagram also includes voltage waveforms of the two sub-components of the first voltage component, i.e., u. in1_1 Waveform diagram and u in1_2 A waveform diagram.

[0147] Figure 7 The frequency of the first voltage component shown is f a The frequencies of the first sub-voltage component and the first sub-voltage component are both f. a There is a phase difference between the first sub-voltage components; their amplitudes are the same, but their directions are opposite, and their frequencies are the same. The phase difference can be determined according to usage requirements and is not limited here; for example, it could be a quarter of a cycle. The amplitude of both the first and second sub-voltage components is 0.5µs. dc .

[0148] Figure 7 The waveform shown on the right is the waveform of the first voltage component. The first voltage component is obtained from the first voltage sub-component and the second voltage sub-component, and the waveform of the first voltage component is also obtained from the waveforms of the first voltage sub-component and the second voltage sub-component. For example, it can be obtained by superimposing waveforms.

[0149] The first voltage component can be represented by u. in1 It means, u in1 =u in1_1 +u in1_2 .

[0150] For example, the effective value of the first voltage component can be determined based on the duty cycle, for instance, based on the duty cycle of the first voltage sub-component and the duty cycle of the second voltage sub-component.

[0151] For example, the duty cycle of the first voltage sub-component is the same as that of the second voltage sub-component.

[0152] For example, the duty cycle of the first voltage component is called the first duty cycle, which can be represented by α.

[0153] For example, the waveform of the first voltage component is a square wave.

[0154] In one embodiment, the output voltage includes a second voltage component with a frequency of a second frequency.

[0155] The first controlled switch is turned on, the sixth and seventh controlled switches are turned on, and the remaining controlled switches are turned off.

[0156] The first controlled switch is turned on, and the sixth and seventh controlled switches are turned on at the second frequency.

[0157] refer to Figure 8 This is a schematic diagram of the operating state of another multi-level inverter circuit 1, showing the first controlled switch S in the first bridge arm. a1 On, the sixth controlled switch S in the second bridge arm b2 and the seventh controlled switch S b3 When the circuit is turned on, the other controlled switches are turned off.

[0158] First controlled switch S a1 The sixth controlled switch S b2 and the seventh controlled switch S b3 The conduction frequency is the second frequency, and the multi-level inverter circuit 1 is in the PO operating state. The second voltage component of the multi-level inverter circuit 1 is u. in2 =0.5u dc .

[0159] refer to Figure 9 This is a schematic diagram of the operating state of another multi-level inverter circuit 1, showing the fourth controlled switch S in the first bridge arm. a4 On, the sixth controlled switch S in the second bridge arm b2 and the seventh controlled switch S b3 When the circuit is turned on, the other controlled switches are turned off.

[0160] Fourth controlled switch S a4 The sixth controlled switch S b2 and the seventh controlled switch S b3 The conduction frequency is the third frequency, the multi-level inverter circuit 1 is in the NO operating state, and the third voltage component of the multi-level inverter circuit 1 is u. in3 =-0.5u dc .

[0161] refer to Figure 10 This is a waveform diagram of an output voltage. Figure 10 The waveform of the synthesized output voltage corresponding to the voltage components at three frequencies is shown in the figure.

[0162] Second voltage component u in2 The frequency can be denoted as f b The third voltage component u in3 The frequency can be denoted as f c The second voltage component u in2 The amplitude and the third voltage component u in3 The amplitude is 0.5u. dc The direction of the second voltage component is positive, and the direction of the third voltage component u in3The direction is negative. The second voltage component u in2 The duty cycle is β, and the third voltage component u in3 The duty cycle is γ.

[0163] Within the same time period, the first voltage component and the second voltage component overlap, and their amplitudes are superimposed. The first voltage component and the third voltage component also overlap, and their amplitudes are superimposed.

[0164] For example, the first frequency, the second frequency, and the third frequency can be different, including but not limited to f. a <f b <f c .

[0165] Figure 10 The waveform on the right is the output voltage waveform of the multi-level inverter circuit 1, which contains three voltage components of different frequencies, thus enabling the output of multiple voltage components.

[0166] refer to Figure 11 This is a schematic diagram of the output voltage of another multilevel inverter circuit. a1 =~S a3 S a2 =~S a4 S b2 =~S b4 S b1 =~S b3 That is, the first controlled switch and the third controlled switch are complementary in conduction, thereby according to Figures 5 to 8 The switch state shown generates three frequencies f a f a f b and f c voltage signal u in1_1 u in1_2 u in2 and u in3 Thus, the AC output voltage u containing the three-frequency AC voltages is obtained by superposition. in Furthermore, the effective value of each voltage component is determined based on the duty cycle of each voltage component.

[0167] Based on the above modulation process, the maximum switching frequency of the system containing this multi-level inverter circuit is the highest frequency among the three voltage components, which is the theoretically feasible lowest switching frequency. This reduces the problem of excessively high switching frequency and high switching losses in multi-frequency wireless charging systems.

[0168] Meanwhile, the above modulation method can achieve independent control of the output voltage corresponding to three different frequency voltage components in a multi-level inverter circuit by adjusting the duty cycle of the complementary switching sequence, without affecting other voltage components, thus reducing the problem that multi-powered device systems cannot independently control the output of three or more power-receiving devices.

[0169] The above embodiments illustrate the circuit structure of a three-level inverter circuit and the switching states of each controlled switch, enabling the three-level inverter circuit to output an output voltage containing three frequency components. Multi-level inverters can also be five-level, seven-level, nine-level, or other inverter circuits with more levels. The circuit structures of different inverter circuits differ, as long as they can output an output voltage containing multiple frequency components. Different inverter circuits output output voltages containing multiple different frequency components, and the on / off states of the controlled switches differ.

[0170] For example, a three-level inverter circuit can output u dc / 2、u dc -u dc / 2、-u dc Four voltage components.

[0171] A five-level inverter circuit can output u dc / 4、u dc / 2、3u dc / 4、u dc -u dc / 4、-u dc / 2、-3u dc / 4、-u dc Eight voltage components.

[0172] An N-level inverter circuit can output (N-1)*2 different voltage components. These voltage components can be superimposed to obtain an output voltage containing multiple voltage components of different frequencies.

[0173] In one embodiment, Figure 12 This is a schematic diagram of a charging system. (Combined with...) Figure 1 and Figure 12 The transmitting circuit 3 includes a transmitting coil.

[0174] Resonant circuit 2 includes:

[0175] The first inductor has one end connected to the first output terminal;

[0176] The third capacitor is connected in series between the first inductor and the transmitting coil;

[0177] The fourth capacitor is connected in parallel with the first inductor;

[0178] The first equivalent impedance of the first inductor and the fourth capacitor resonates in series with the third capacitor and the transmitting coil, and the transmitting coil resonates with the first receiving circuit at the first frequency; the first equivalent impedance is an inductive impedance.

[0179] The first inductor and the fourth capacitor resonate in parallel, the first inductor, the third capacitor, and the transmitting coil resonate in parallel, and the transmitting coil resonates with the second receiving circuit at the second frequency.

[0180] The second equivalent impedance of the first inductor and the fourth capacitor resonates in series with the third capacitor and the transmitting coil, and the transmitting coil resonates with the first receiving circuit at the third frequency; the second equivalent impedance is a capacitive impedance.

[0181] The transmitting coil can be denoted as L. px The first inductance can be denoted as L. r The third capacitor can be C. r The fourth capacitor can be denoted as C. px Resonant circuit 2 is an LCC topology.

[0182] The angular frequency of the first voltage component is ωa, the angular frequency of the second voltage component is ωb, and the angular frequency of the third voltage component is ωc.

[0183] M s1 For transmitting coil and receiving coil L sa Mutual intuition between them, M s2 For transmitting coil and receiving coil L sb Mutual intuition between them, M s3 For transmitting coil and receiving coil L sc Mutual attraction between them.

[0184] The secondary side consists of three receiver circuits with identical circuit structures but operating at different frequencies. Each receiver circuit includes a receiving coil, and the inductance values ​​of the three receiving coils are L... sa L sb L sc The corresponding resonant capacitances are: C sa C sb C sc Among them, u oa u ob u oc These are the input voltages of the receiving rectifier, C. La C Lb C Lc These are the DC-side energy storage capacitors at the receiving end, R La R Lb and R Lc For power receiving equipment, u La u Lb u Lc and iLa i Lb i Lc These represent the voltage and current of the receiving equipment, respectively.

[0185] L sa L sb L sc Given a quantity, C sa C sb C sc Unknown quantity, C sa According to L sa Confirmed, C sb According to L sb Confirmed, C sc According to L sc Sure.

[0186] refer to Figure 13 This is an equivalent circuit diagram of an output voltage component at a first frequency, using an SS-structured topology. In this embodiment, the first receiving end includes a first receiving circuit, and the first receiving circuit includes a first receiving coil.

[0187] First inductor L r With the third capacitor C r The equivalent impedance in parallel and the fourth capacitor C px and transmitting coil L px The series circuit achieves complete resonance. At this point, the primary and secondary sides of the charging system must satisfy the following resonance conditions, namely, the resonance conditions satisfied by the resonant circuit, transmitting circuit, and receiving circuit are as follows:

[0188]

[0189] Among them, Z r，1 For L r With C r At the operating frequency f a The equivalent inductive impedance in parallel is expressed as follows:

[0190]

[0191] In this state, the first receiving end achieves constant current input.

[0192] refer to Figure 14 This is an equivalent circuit diagram of an LCC-S topology circuit when outputting a second voltage component at a second frequency. In this embodiment, the second receiving end includes a second receiving circuit, and the second receiving circuit includes a second receiving coil.

[0193] First inductor L r With the third capacitor C r Parallel full resonance, first inductor L r Fourth capacitor Cpx and transmitting coil L px Parallel circuit achieves full resonance. At this point, the primary and secondary sides of the charging system must satisfy the following resonance conditions, namely, the resonance conditions satisfied by the resonant circuit, transmitting circuit, and receiving circuit are as follows:

[0194]

[0195] refer to Figure 15 This is an equivalent circuit diagram of an SS-structured topology circuit when outputting a third voltage component at a third frequency. In this embodiment, the third receiving end includes a third receiving circuit, and the third receiving circuit includes a third receiving coil.

[0196] First inductor L r With the third capacitor C r The equivalent impedance in parallel, and the fourth capacitor C px and transmitting coil L px The series circuit achieves complete resonance. At this point, the primary and secondary sides of the charging system must satisfy the following resonance conditions, namely, the resonance conditions satisfied by the resonant circuit, transmitting circuit, and receiving circuit are as follows:

[0197]

[0198] Among them, Z r，2 For L r With C r At the operating frequency f c The equivalent parallel impedance at the operating frequency f c The following exhibits capacitive properties, and its expression is:

[0199]

[0200] In formulas (4)-(8), the unknown parameter is L. r C r and C px Given parameters including the self-inductance L of the transmitting coil px angular frequency ω a ω b ω c In formulas (4)-(8), there are 3 unknown parameters and 5 equations. According to the condition that a system of linear equations has a solution, the parameters of all components can be solved using formulas (4)-(8). The detailed solution formulas are as follows:

[0201]

[0202] This allows us to obtain the parameter values ​​of each component in the resonant circuit. Through this resonant circuit, three-frequency resonance can be achieved, wirelessly transmitting the energy corresponding to the three different frequency current components. This wireless energy transmission circuit can be used for a resonant frequency of f. a f b and f c The receiving circuit provides energy. This reduces the number of components in the resonant circuit, reduces the complexity of the resonant circuit, and thus reduces the size and weight of the resonant circuit. The parameters of each component are simple and easy to determine.

[0203] The parameters of the resonant capacitor in the receiving circuit can be determined by the following formula:

[0204]

[0205] In one embodiment, reference Figure 16 This is an equivalent circuit diagram of a resonant circuit, a transmitting circuit, and a receiving circuit.

[0206] Among them, u pra u prb u prc These are the induced voltages, u, generated on the primary side by the currents in the three receiving coils. sra u srb u src The transmitting coil L is respectively px The induced voltage u generated by the current in the three receiving coils srab u srbc u srac This is the induced voltage between the three receiving coils, and its expression is shown in equation (15):

[0207]

[0208] Among them, M s1 M s2 M s3 The transmitting coil L is respectively px Mutual inductance between the three receiving coils; M ab M bc M ac This refers to the mutual inductance between the receiving coils.

[0209] The system voltage-current relationship matrix is ​​as follows:

[0210]

[0211] in, For the first inductor L r impedance, The fourth capacitor C px and the third capacitor Cr impedance; Then, calculate the loop impedance of the receiving circuit in each of the three receiving terminals.

[0212] The above circuit equations can be used to solve for expressions of coil current, voltage of each powered device, system output power, and efficiency at different frequencies.

[0213] In one embodiment, a charging device is also provided, comprising: the wireless power transmission circuit of any of the above embodiments.

[0214] In one embodiment, a charging system is also provided, comprising:

[0215] The wireless power transmission circuit in any of the above embodiments;

[0216] Multiple power receiving devices, each with its own receiving circuit, are wirelessly connected to and resonate with the transmitting circuit in the wireless power transmission circuit. The transmitting circuit resonates at different frequencies with the different receiving circuits. The receiving circuit is used to receive the energy transmitted by the transmitting circuit. The energy is used to power the power receiving devices.

[0217] refer to Figure 12 This illustrates the relationship between a wireless power transfer circuit and a powered device, the powered device including a receiving circuit and... Figure 12 Other components shown include energy storage capacitors and loads.

[0218] Figure 12 Three receiving devices are shown: receiver 1, receiver 2, and receiver 3. Each receiver includes a receiving circuit, which in turn includes a receiving coil. s1 For transmitting coil and receiving coil L sa Mutual intuition between them, M s2 For transmitting coil and receiving coil L sb Mutual intuition between them, M s3 For transmitting coil and receiving coil L sc Mutual attraction between them.

[0219] The secondary side consists of three receiver circuits with identical circuit structures but operating at different frequencies. Each receiver circuit includes a receiving coil, and the inductance values ​​of the three receiving coils are L... sa L sb L sc The corresponding resonant capacitances are: C sa C sb C sc Among them, u oa u ob u oc These are the input voltages of the receiving rectifier, C. La CLb C Lc These are the DC-side energy storage capacitors at the receiving end, R La R Lb and R Lc For power receiving equipment, u La u Lb u Lc and i La i Lb i Lc These represent the voltage and current of the receiving equipment, respectively.

[0220] L sa L sb L sc Given a quantity, C sa C sb C sc C is an unknown quantity. sa According to L sa Confirmed, C sb According to L sb Confirmed, C sc According to L sc Sure.

[0221] This charging system allows the wireless energy transmission circuit to emit energy corresponding to multiple voltages at different frequencies, thereby enabling the charging of multiple devices. It also allows for the individual adjustment of each voltage component.

[0222] The wireless power transmission circuit can be found at least in the charger of the terminal device. The terminal device can include mobile terminal devices and fixed terminal devices, meaning that the entity executing this method can include at least mobile terminal devices and fixed terminal devices. Mobile terminal devices can include mobile phones, tablets, in-vehicle central control devices, wearable devices, smart devices, and aircraft, etc., while smart devices can include smart office equipment, smart home equipment, and robots, etc.

[0223] The circuit topology provided in this embodiment, through a three-frequency input current-voltage modulation method and a primary-side three-frequency resonant network and its parameter design method, can realize the function of a wireless power transmission system with independent control of three-frequency and three-load outputs. This reduces the maximum switching frequency of the multi-frequency, multi-load wireless charging system to the maximum value of the receiving coil's resonant frequency. It also increases the maximum number of independently controllable loads across multiple frequencies and loads; reduces the number of components in the multi-frequency network; and lowers the system's size and weight.

[0224] In one embodiment, the technical solution provided in this embodiment belongs to the field of wireless power transmission, specifically a multi-frequency, multi-load wireless power transmission system design, applicable to electronic devices. For example, this solution is a tri-frequency wireless power transmission system capable of simultaneously transmitting power to three loads. This technical solution can be extended to other types of wireless power transmission systems, such as electric field-based wireless power transmission systems and ultrasonic wireless power transmission systems.

[0225] refer to Figure 1 and Figure 12 The topology diagram of the three-frequency three-load wireless power transmission system proposed in this invention patent is shown.

[0226] The multilevel inverter circuit 1 in this embodiment includes a single-phase T-type neutral-point-clamped (NPC) three-level inverter circuit, used to output a frequency f m The mixed alternating current of voltage components (m = a, b, c) has corresponding angular frequencies ω. a ω b ω c This single-phase T-type neutral-point-clamped (NPC) three-level inverter circuit can be applied in three-level inverters.

[0227] Among them, u dc This is a DC input voltage source, where P and N represent the positive and negative terminals of the DC side voltage, respectively, and O is the DC side midpoint. C a and C b This refers to two discrete capacitors on the DC side, which are usually chosen with the same capacitance value to maintain the balance of their midpoint potentials, i.e., u1 = u2 = 0.5u. dc A T-type single-phase three-level inverter consists of two bridge arms, a and b, each containing four switching transistors, using S... xj (x = a, b; j = 1, 2, 3, 4) represents the expression when S xj A value of "1" indicates the switch is on, and a value of "0" indicates the switch is off. Each pair of bridge arms has two sets of switching transistors S... x1 and S x3 and S x2 and S x4 Complementary conduction is used to avoid the influence of current direction on the driving of switching devices during commutation. Furthermore, S x1 With S x4 Simultaneous conduction is also prohibited to prevent straight-through of the bridge arms. in i in These represent the output voltage and current of the inverter, i o It is a neutral current.

[0228] The primary-side compensation network includes the transmitting coil Lpx By L r With C px The circuit consists of a series LC branch and a parallel capacitor C. r This means the original edge is an LCC topology. M s1 M s2 M s3 These are the mutual inductances between the transmitting coil and the three receiving coils.

[0229] The secondary side consists of three receiver circuits with identical circuit structures but operating at different frequencies. Each receiver circuit includes a receiving coil, and the inductance values ​​of the three receiving coils are L... sa L sb L sc The corresponding resonant capacitances are: C sa C sb C sc Among them, u oa u ob u oc These are the input voltages of the receiving rectifier, C. La C Lb C Lc These are the DC-side energy storage capacitors at the receiving end, R La R Lb and R Lc For power receiving equipment, u La u Lb u Lc and i La i Lb i Lc These represent the voltage and current of the receiving equipment, respectively.

[0230] Figure 16 The equivalent circuit diagram of the three-frequency, three-load wireless power transmission system provided in this embodiment is shown. Wherein, u pra u prb u prc These are the induced voltages, u, generated on the primary side by the currents in the three receiving coils. sra u srb u src The transmitting coil L is respectively px The induced voltage u generated by the current in the three receiving coils srab u srbc u srac This is the induced voltage between the three receiving coils, and its expression is shown in equation (15).

[0231] The system voltage-current relationship matrix is ​​as follows:

[0232] Depending on the output voltage, each arm of a single-phase T-type three-level inverter has three different operating modes: P, O, and N states, indicated by the switching transistor S. aj Taking the bridge arm as an example, its equivalent electrical diagrams under three switching states are as follows: Figures 2 to 4 As shown.

[0233] P state as Figure 2 As shown, at this time, the switching transistor S x1 With the circuit turned on, taking point O as the reference point, when the voltages of the two capacitors on the DC side are in equilibrium, the output voltage u a =u1=0.5u dc O state as Figure 3 As shown, at this time, the switching transistor S a2 and S a3 When the inverter is turned on, the output voltage is 0. Figure 4 This demonstrates the switching state in N, where the switching transistor S... a4 When the circuit is turned on, the output voltage is u. a =-u2=-0.5u dc .

[0234] Similarly, taking the switching transistor S... bj The bridge arms also have the above three output states and output characteristics. Table 1 lists the switching states and outputs of a single-phase T-type NPC three-level inverter, where u x (x = a, b) represent the voltage u output by a single bridge arm, respectively. a u b Since each bridge arm has three switching states: P, O, and N, the single-phase T-type three-level inverter has a total of 9 switching states, as shown in Table 2.

[0235] Multi-frequency modulation strategy, i.e., the control of the state of each controlled switch in a three-level inverter circuit:

[0236] To enable the transmitting coil to have a mixed-frequency current, the three-level inverter output needs to contain voltages of three different frequencies. This can be achieved through methods such as... Figure 7 The voltage components of different frequencies shown are superimposed. Figure 7 In the middle, the frequency is f a The first voltage component u in1 Two square wave voltages u with the same frequency, opposite amplitude, and a phase difference of one-quarter of a cycle are respectively generated. in1_1 with u in1_2 The effective value is determined by the duty cycle α, and is formed by superposition. Figure 10 The middle is the three-frequency voltage u in The superposition diagram shows the second voltage component u. in2 The amplitude is 0.5u dc The frequency is f bThe effective value is determined by the duty cycle β. The third voltage component u in3 The amplitude is -0.5u dc The frequency is f c The duty cycle γ determines its effective value. The relationship between the three frequencies is f a <f b <f c .

[0237] For synthesis such Figure 7 The frequency shown is f a The first voltage component u in1 It requires an amplitude of 0.5u to be superimposed. dc voltage component u in1_1 With an amplitude of -0.5u dc voltage component u in1_2 According to Table 2, to achieve a 0.5u output from the T-type NPC three-level inverter... dc The voltage is such that this scheme uses switch S of bridge arm a. a2 With S a3 On, bridge arm b switch S b1 Shut down and S b4 The output u is produced when the switch is in the ON state. in1_1 Its frequency is f a Switching operating modes such as Figure 5 As shown. Let the OP state output u. in1_2 Working modes such as Figure 6 As shown, at this time, switch S of bridge arm a... a2 With S a3 On, bridge arm b switch S b4 Shut down and S b1 When the circuit is turned on, the corresponding frequency is also f. a .

[0238] Figure 8 This demonstrates the operating mode of the three-level inverter in the PO state, specifically the bridge arm a switch S. a4 Shutdown, S a1 On, bridge arm b switch S b2 With S b3 When the inverter is turned on, its output frequency is set to f. b The second voltage component u in2 .

[0239] To generate frequency f c The third voltage component u in3 , switch S on bridge arm a a1 Shutdown, S a4 On, bridge arm b switch S b2 With S b3 Simply turn it on; at this point, the inverter will operate in the NO state, such as... Figure 9 As shown.

[0240] Based on the above analysis, Figure 10 and Figure 11 This diagram illustrates the overall output of a T-type midpoint clamped NPC three-level inverter at mixed frequencies, including four sets of complementary switches S. a1 =~S a3 S a2 =~S a4 S b2 =~S b4 S b1 =~S b3 Alternating conduction generates frequencies f respectively. a f a f b and f c Four different voltage signals u in1_1 u in1_2 u in2 and u in3 Thus, the three-frequency AC voltage output u is superimposed. in Furthermore, the effective value percentage of each voltage component is determined by its corresponding duty cycle.

[0241] Based on the modulation method described above, the system's maximum switching frequency is the largest resonant frequency f among the three loads. c This is the theoretically feasible minimum switching frequency, which solves the problem of excessively high switching frequencies and large switching losses in existing multi-frequency wireless charging systems.

[0242] Meanwhile, the above modulation method can achieve independent control of the output voltage corresponding to the three different frequency components in the inverter by adjusting the duty cycle of the complementary switching sequence, without affecting other components, thus solving the problem that multi-load systems cannot independently control the output of three or more loads.

[0243] In one embodiment, according to Figure 16 The system equivalent circuit diagram shown is for a system operating at frequency f. a At that time, the system can be decoupled and equivalent to, for example, Figure 13 The SS topology circuit shown provides a constant current output from receiver 1. Where L... r With C r The equivalent impedance of parallel circuits and C px L px The series circuit achieves complete resonance. At this point, the resonance conditions that the primary and secondary sides of the system should satisfy are shown in equations (4) and (5).

[0244] When the system operates at frequency f b At that time, the system can be equivalent to, for example, Figure 14In the LCC-S topology shown, receiver 2 achieves constant voltage output. By designing Lr and Cr as parallel fully resonant, and Lr, Cpx, and Lpx as parallel fully resonant, the resonance conditions of the primary and secondary sides of the system can be obtained as shown in formula (6).

[0245] With the system operating at frequency f a Similarly, when the system operates at frequency f c At this time, the primary side and the receiver's three loops also form an SS equivalent topology, achieving constant current output. Its equivalent circuit diagram is as follows: Figure 15 As shown. The equivalent impedance of Lr and Cr in parallel resonates completely in series with Cpx and Lpx. The resonance conditions of the primary and secondary sides of the system are shown in formulas (7) and (8).

[0246] In formulas (4)-(8), the unknown parameter is L. r C r and C px Given parameters including the self-inductance L of the transmitting coil px angular frequency ω a ω b ω c In formulas (4)-(8), there are 3 unknown parameters and 5 equations. According to the condition that a system of linear equations has a solution, all component parameters can be solved using formulas (4)-(8). The parameters of each component are shown in formulas (9) to (14).

[0247] The technical solution provided in this embodiment can be applied to wireless charging scenarios for mobile devices, including wireless charging scenarios where multiple devices are charged simultaneously. This solution not only provides power to multiple devices simultaneously through different frequency channels, but also allows for individual adjustment of the input voltage duty cycle corresponding to different frequencies. This enables independent adjustment of charging voltage, current, or power for different loads, simplifying the coil structure and compensation network structure of the system, reducing system costs, and improving user experience.

[0248] It should be noted that the terms "first" and "second" in the embodiments of this disclosure are for ease of description and distinction only, and have no other specific meaning.

[0249] Figure 17 This is a block diagram illustrating a terminal device according to an exemplary embodiment. For example, the terminal device may include a charging device and / or a power receiving device, and may be a mobile phone with image processing capabilities, a computer, a digital broadcasting terminal, a messaging device, a game console, a tablet device, a medical device, a fitness device, a personal digital assistant, etc.

[0250] Reference Figure 17The terminal device may include one or more of the following components: processing component 802, memory 804, power component 806, multimedia component 808, audio component 810, input / output (I / O) interface 812, sensor component 814, and communication component 816.

[0251] Processing component 802 typically controls the overall operation of the terminal device, such as operations associated with display, telephone calls, data communication, camera operation, and recording. Processing component 802 may include one or more processors 820 to execute instructions to complete all or part of the steps of the methods described above. Furthermore, processing component 802 may include one or more modules to facilitate interaction between processing component 802 and other components. For example, processing component 802 may include a multimedia module to facilitate interaction between multimedia component 808 and processing component 802.

[0252] Memory 804 is configured to store various types of data to support operation on the terminal device. Examples of this data include instructions for any application or method operating on the terminal device, contact data, phonebook data, messages, pictures, videos, etc. Memory 804 can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as Static Random Access Memory (SRAM), Electrically Erasable Programmable Read Only Memory (EEPROM), Erasable Programmable Read-Only Memory (EPROM), Programmable Read Only Memory (PROM), Read-Only Memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk.

[0253] Power component 806 provides power to various components of the terminal device. Power component 806 may include a power management system, one or more power supplies, and other components associated with generating, managing, and distributing power to the terminal device.

[0254] Multimedia component 808 includes a screen that provides an output interface between the terminal device and the user. In some embodiments, the screen may include a Liquid Crystal Display (LCD) and a Touch Panel (TP). If the screen includes a Touch Panel, the screen can be implemented as a touchscreen to receive input signals from the user. The Touch Panel includes one or more touch sensors to sense touches, swipes, and gestures on the Touch Panel. The touch sensors can sense not only the boundaries of touch or swipe actions but also the duration and pressure associated with the touch or swipe operation. In some embodiments, multimedia component 808 includes a front-facing camera and / or a rear-facing camera. When the terminal device is in an operating mode, such as a shooting mode or a video mode, the front-facing camera and / or the rear-facing camera can receive external multimedia data. Each front-facing camera and rear-facing camera can be a fixed optical lens system or have focal length and optical zoom capabilities.

[0255] Audio component 810 is configured to output and / or input audio signals. For example, audio component 810 includes a microphone (MIC) configured to receive external audio signals when the terminal device is in an operating mode, such as call mode, recording mode, and voice recognition mode. The received audio signals may be further stored in memory 804 or transmitted via communication component 816. In some embodiments, audio component 810 also includes a speaker for outputting audio signals.

[0256] I / O interface 812 provides an interface between processing component 802 and peripheral interface modules, such as keyboards, click wheels, buttons, etc. These buttons may include, but are not limited to, home buttons, volume buttons, power buttons, and lock buttons.

[0257] Sensor assembly 814 includes one or more sensors for providing status assessments of various aspects of the terminal device. For example, sensor assembly 814 can detect the on / off state of the terminal device, the relative positioning of components such as the display and keypad of the terminal device, changes in the position of the terminal device or a component of the terminal device, the presence or absence of user contact with the terminal device, the orientation or acceleration / deceleration of the terminal device, and temperature changes of the terminal device. Sensor assembly 814 may include a proximity sensor configured to detect the presence of nearby objects without any physical contact. Sensor assembly 814 may also include an optical sensor, such as a Complementary Metal Oxide Semiconductor (CMOS) or Charge Coupled Device (CCD) image sensor, for use in imaging applications. In some embodiments, sensor assembly 814 may also include an accelerometer, a gyroscope, a magnetometer, a pressure sensor, or a temperature sensor.

[0258] Communication component 816 is configured to facilitate wired or wireless communication between terminal devices and other devices. The terminal device can access wireless networks based on communication standards, such as Wi-Fi, 4G, or 5G, or combinations thereof. In one exemplary embodiment, communication component 816 receives broadcast signals or broadcast-related information from an external broadcast management system via a broadcast channel. In one exemplary embodiment, communication component 816 also includes a Near Field Communication (NFC) module to facilitate short-range communication. For example, the NFC module may be implemented based on Radio Frequency Identification (RFID), Infrared Data Association (IrDA), Ultra Wide Band (UWB), Bluetooth (BT), and other technologies.

[0259] In an exemplary embodiment, the terminal device may be implemented by one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), controllers, microcontrollers, microprocessors, or other electronic components to perform the methods described above.

[0260] In an exemplary embodiment, a non-transitory computer-readable storage medium including instructions is also provided, such as a memory 804 including executable instructions or a computer program, which can be executed by the processor 820 of the device 800 to perform the above-described method. For example, the non-transitory computer-readable storage medium may be a ROM, random access memory (RAM), a compact disc read-only memory (CD-ROM), magnetic tape, floppy disk, and optical data storage device, etc.

[0261] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This disclosure is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the following claims.

[0262] It should be understood that this disclosure is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this disclosure is limited only by the appended claims.

Claims

1. A wireless energy transfer circuit, characterized by, include: A multi-level inverter circuit has a first input terminal and a first output terminal. The first input terminal is electrically connected to a DC power supply and is used to output an AC output voltage containing at least one voltage component according to the DC supply voltage of the DC power supply; wherein the different voltage components have different frequencies; and wherein the maximum number of voltage components is greater than 2. A resonant circuit has a second input terminal and a second output terminal. The second input terminal is electrically connected to the first output terminal, and the second output terminal is electrically connected to a transmitting circuit. It is used to obtain the current component corresponding to the voltage component based on the AC output voltage, so that the transmitting circuit emits energy corresponding to the current component at different frequencies. The transmitting circuit is used to transmit the energy corresponding to each of the current components wirelessly.

2. The circuit of claim 1, wherein, Also includes: The controller is electrically connected to the multilevel inverter circuit and is used to control the operating state of the multilevel inverter circuit so that the multilevel inverter circuit outputs the AC output voltage.

3. The circuit according to claim 1, characterized in that, The number of voltage components in the AC output voltage of the multilevel inverter circuit with different circuit structures is different. or, The number of voltage components contained in the AC output voltage of the multilevel inverter circuits with different circuit structures is the same. or, The same multi-level inverter circuit may have different numbers of voltage components in its output AC output voltage.

4. The circuit according to claim 1, characterized in that, The multi-level inverter circuit includes: A single-phase multi-level inverter circuit is used to output the AC output voltage based on the single-phase DC power output from the DC power supply.

5. The circuit according to claim 1, characterized in that, The voltage components each have their own duty cycle, and the effective value of each voltage component is determined based on its respective duty cycle.

6. The circuit of claim 2, wherein, The controller has multiple control modes; In different control modes, the number of voltage components contained in the AC output voltage is different, and / or, at least some of the voltage components have different frequencies.

7. The circuit of claim 2, wherein, The multi-level inverter circuit includes: Multiple controlled switches are connected to the controller, respectively; wherein the multi-level inverter circuit outputs voltage components of different frequencies, and the controlled switches have different switching states.

8. The circuit of claim 2, wherein, The multi-level inverter circuit includes a single-phase three-level inverter circuit; the single-phase three-level inverter circuit includes: First capacitor; The second capacitor is connected in series with the first capacitor between the positive and negative terminals of the DC power supply. The first controlled switch has its drain connected to the positive terminal of the DC power supply and its gate connected to the controller. The second controlled switch has its drain connected between the first capacitor and the second capacitor, and its gate connected to the controller; The third controlled switch has its source connected to the source of the second controlled switch, its drain connected to the source of the first controlled switch, and its gate connected to the controller. The fourth controlled switch has its drain connected to the source of the first controlled switch, its source connected to the negative terminal, and its gate connected to the controller. The fifth controlled switch has its drain connected to the positive terminal and its gate connected to the controller. The sixth controlled switch has its drain connected between the first capacitor and the second capacitor, and its gate connected to the controller. The seventh controlled switch has its source connected to the source of the sixth controlled switch, its drain connected to the source of the fifth controlled switch, and its gate connected to the controller. The eighth controlled switch has its drain connected to the source of the fifth controlled switch, its source connected to the negative terminal, and its gate connected to the controller. Wherein, the first controlled switch, the second controlled switch, the third controlled switch and the fourth controlled switch form the first bridge arm, and the fifth controlled switch, the sixth controlled switch, the seventh controlled switch and the eighth controlled switch form the second bridge arm; the connection point of the first capacitor and the second capacitor serves as the midpoint of the DC side; The connection point of the source of the first controlled switch, the drain of the third controlled switch, and the drain of the fourth controlled switch serves as the positive terminal of the first output terminal; the connection point of the source of the fifth controlled switch, the drain of the seventh controlled switch, and the drain of the eighth controlled switch serves as the negative terminal of the first output terminal.

9. The circuit of claim 8, wherein, The output voltage includes a first voltage component with a first frequency; The second controlled switch, the third controlled switch, and the fifth controlled switch are turned on; The second controlled switch, the third controlled switch, and the eighth controlled switch are turned on; The fifth and eighth controlled switches are alternately turned on, while the remaining controlled switches are turned off; the conduction frequency of the second, third, fifth, and eighth controlled switches is the first frequency.

10. The circuit of claim 8, wherein, The output voltage includes a second voltage component with a second frequency; The first controlled switch is turned on, the sixth controlled switch and the seventh controlled switch are turned on, and the remaining controlled switches are turned off; Wherein, the first controlled switch is turned on, and the conduction frequency of the sixth and seventh controlled switches is the second frequency.

11. The circuit of claim 8, wherein, The output voltage includes a third voltage component with a frequency of the third frequency; The fourth controlled switch is turned on, the sixth controlled switch and the seventh controlled switch are turned on, and the remaining controlled switches are turned off; The conduction frequency of the fourth controlled switch, the sixth controlled switch, and the seventh controlled switch is the third frequency.

12. The circuit of claim 1, wherein, The transmitting circuit includes a transmitting coil; The resonant circuit includes: The first inductor has one end connected to the first output terminal; A third capacitor is connected in series between the first inductor and the transmitting coil. The fourth capacitor is connected in parallel with the first inductor; Wherein, the first equivalent impedance of the first inductor and the fourth capacitor resonates in series with the third capacitor and the transmitting coil, and the transmitting coil resonates with the first receiving circuit at a first frequency; the first equivalent impedance is an inductive impedance; The first inductor and the fourth capacitor resonate in parallel, the first inductor, the third capacitor and the transmitting coil resonate in parallel, and the transmitting coil resonates with the second receiving circuit at a second frequency; The second equivalent impedance of the first inductor and the fourth capacitor resonates in series with the third capacitor and the transmitting coil, and the transmitting coil resonates with the first receiving circuit at a third frequency; the second equivalent impedance is a capacitive impedance.

13. A charging device, characterized by include: The wireless power transfer circuit according to any one of claims 1 to 12.

14. A charging system, characterized by include: The wireless power transfer circuit according to any one of claims 1 to 12; Multiple power receiving devices are provided, each having its own receiving circuit. Each receiving circuit is wirelessly connected to and resonates with a transmitting circuit in the wireless power transmission circuit. The transmitting circuit resonates at different frequencies with different receiving circuits. The receiving circuit is used to receive energy transmitted by the transmitting circuit. The energy is used to power the power receiving devices.

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