A topology of a wireless charging system

Abstract

The application belongs to the technical field of wireless charging and provides a topological structure of a wireless charging system, comprising: a primary side module, an inverter being arranged in the primary side module; a secondary side module; a magnetic coupling coil, comprising a transmitting end coil connected with an output end of the inverter and a receiving coil connected with an input end of the secondary side module; the transmitting end coil is provided with two coils connected in series, and the receiving end coil is one coil; a controller electrically connected with the inverter controls the on-off of the inverter by identifying the distance between the receiving end coil and the two transmitting end coils, so that the transmitting end coil with the minimum distance from the receiving end coil performs electric energy transmission. The application has the advantages that the controller identifies the position of the receiving end coil to form multiple different working modes, so that the position offset of the coil at the electronic product end and the coil at the charging seat end is amplified, and the user can conveniently perform effective charging.

Description

Technical Field

[0001] This invention relates to the field of wireless charging technology, and more particularly to a topology of a wireless charging system. Background Technology

[0002] Wireless power transfer, also known as wireless power transmission or contactless power transfer, refers to a transmission method that converts electrical energy into other forms of relay energy (such as electromagnetic field energy, laser, microwave, and mechanical waves) through a transmitter, transmits it over a distance, and then converts the relay energy back into electrical energy through a receiver, thus realizing wireless power transfer.

[0003] In recent years, portable electronic devices such as laptops, mobile phones, and music players have required batteries and charging. Frequent plugging and unplugging of power cords is unsafe, unsightly, unreliable, and prone to wear and tear. Furthermore, the standards for chargers, cords, and sockets are not entirely standardized, leading to waste and environmental pollution. This has spurred the development of wireless charging electronic products.

[0004] However, in actual charging, the coil on the electronic product side and the coil on the charging base side must be accurately positioned for effective charging. This can restrict the placement of the user's electronic product and affect the user's charging experience. Summary of the Invention

[0005] The purpose of this invention is to provide a topology for a wireless charging system to solve the problem of insufficient positional offset between the coil at the electronic product end and the coil at the charging base end.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A topology for a wireless charging system includes:

[0008] Primary-side module, wherein an inverter is provided in the primary-side module;

[0009] Secondary side module;

[0010] The magnetic coupling coil includes a transmitting coil connected to the output terminal of the inverter and a receiving coil connected to the input terminal of the secondary module;

[0011] The transmitting coil has two coils connected in series, and the receiving coil is a single coil. The controller, which is electrically connected to the inverter, identifies the distance between the receiving coil and the two transmitting coils and controls the switching on and off of the inverter so that the transmitting coil with the smallest distance from the receiving coil can transmit electrical energy.

[0012] Furthermore, the inverter includes three bridge arms, each of which is equipped with two switching transistors; one end of the first transmitting coil is connected to the node between the two switching transistors of the second bridge arm via a first compensation capacitor, one end of the second transmitting coil is connected to the node between the two switching transistors of the first bridge arm via a second compensation capacitor, and the connection point between the first and second transmitting coils is connected to the node between the two switching transistors of the third bridge arm.

[0013] Furthermore, when the controller detects that the receiving coil is closest to the first transmitting coil, the controller turns on the switching transistors of the second and third bridge arms and turns off the switching transistor of the first bridge arm, so that power can be transferred through the coupling of the first transmitting coil and the receiving coil.

[0014] When the controller detects that the receiving coil is closest to the second transmitting coil, the controller turns on the switching transistors of the first and third bridge arms and turns off the switching transistor of the second bridge arm, so that power can be transferred through the coupling of the second transmitting coil and the receiving coil.

[0015] When the controller detects that the distance difference between the receiving coil and the two transmitting coils is within a preset value, it turns on the switching transistors of the three bridge arms, and the first transmitting coil and the second transmitting coil are coupled to the receiving coil to transmit electrical energy.

[0016] Furthermore, the switching frequencies of the switching transistors are all the same, and the first transmitting coil and the first compensation capacitor satisfy... Resonance occurs when the first transmitting coil is inducted, C1 is the capacitance of the first compensation capacitor, and f is the switching frequency of the switching transistor.

[0017] The second transmitting coil and the second compensation capacitor satisfy the following conditions: Resonance occurs when the second transmitting coil is inducted, where L2 is the self-inductance of the second transmitting coil, C2 is the capacitance of the second compensation capacitor, and f is the switching frequency of the switching transistor.

[0018] The first transmitting coil and the second transmitting coil are connected in series, and then connected to the first compensation capacitor and the second compensation capacitor, in accordance with the following conditions: Resonance occurs, where M is the mutual inductance between the two transmitting coils.

[0019] Furthermore, the switching frequency of the switching transistor can be adjusted in real time by the controller to ensure that the input impedance angle of the wireless charging system is always zero.

[0020] Furthermore, a common compensation element is provided between the connection point of the first transmitting coil and the second transmitting coil and the node between the two switching transistors of the third bridge arm.

[0021] Furthermore, the switching frequencies of all the switching transistors are the same;

[0022] The first transmitting coil, the first compensation capacitor, and the common compensation element satisfy the following conditions: Resonance occurs at this time, where L1 is the self-inductance of the first transmitting coil, C1 is the capacitance of the first compensation capacitor, and X... 12 The reactance of the common compensation element is given by f, where f is the switching frequency of the switching transistor.

[0023] The second transmitting coil, the second compensation capacitor, and the common compensation element satisfy the following conditions: Resonance occurs at this time, where L2 is the self-inductance of the first transmitting coil, C2 is the capacitance of the first compensation capacitor, and X... 12 The reactance of the common compensation element is given by f, where f is the switching frequency of the switching transistor.

[0024] Furthermore, the inverter includes two bridge arms, each of which is equipped with two switching transistors; the inverter also includes a capacitor bridge arm connected in parallel with the two bridge arms, the capacitor bridge arm including two capacitors connected in series.

[0025] One end of the first transmitting coil is connected to the node between the two switching transistors of the second bridge arm via the first compensation capacitor. One end of the second transmitting coil is connected to the node between the two switching transistors of the first bridge arm via the second compensation capacitor. The connection point between the first and second transmitting coils is connected to the node between the two capacitors of the capacitor bridge arm.

[0026] Furthermore, the three-arm structure in the inverter can be used as a secondary inverter in a wireless charging system or as a primary-secondary dual-side inverter.

[0027] Compared with the prior art, the present invention has at least the following beneficial effects:

[0028] (1) By identifying the position of the receiving coil through the controller, a variety of different working modes are formed, which amplifies the positional offset between the coil at the electronic product end and the coil at the charging dock end, making it convenient for users to charge effectively.

[0029] (2) By adjusting the phase shift between bridge arms and the duty cycle of the switching transistors in the same bridge arm, the voltage value across the transmitting coil is adjusted to control the first transmitting coil or the second transmitting coil or two transmitting coils connected in series to transmit electrical energy.

[0030] (3) A common compensation element is set between the connection point of the first transmitting coil and the second transmitting coil and the node between the two switching tubes of the third bridge arm. The common compensation element forms a self-resonant loop to adjust the transmission efficiency of the transmitting coil.

[0031] (4) Replacing the third bridge arm with a capacitor bridge arm enables wireless power transmission for low-power electrical devices;

[0032] (5) The two topologies of three bridge arms or two bridge arms plus capacitor bridge arms can be used not only in the primary-side inverter, but also in the secondary-side inverter of the wireless charging system, and can be used in both the primary and secondary sides. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the topology of the wireless charging system in Embodiment 1 of the present invention;

[0034] Figure 2 This is a schematic diagram of the structure of the transmitting coil and the receiving coil in Embodiment 1 of the present invention;

[0035] Figure 3 This is a timing diagram of the phase shifting of the three bridge arms and the duty cycle control of the switching transistors in Embodiment 1 of the present invention;

[0036] Figure 4 This is a schematic diagram of the topology of the wireless charging system in Embodiment 2 of the present invention;

[0037] Figure 5 This is a schematic diagram of the topology of the wireless charging system in Embodiment 3 of the present invention; Detailed Implementation

[0038] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0039] Furthermore, in this invention, descriptions involving terms such as "first," "second," and "a" are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0040] In this invention, unless otherwise explicitly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0041] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0042] The following are specific embodiments of the present invention, and the technical solutions of the present invention will be further described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0043] Example 1

[0044] like Figure 1 As shown, the topology of a wireless charging system of the present invention includes a primary-side module, a secondary-side module, and a magnetically coupled coil.

[0045] The primary-side module includes an inverter, whose input is connected to an input DC power supply, and whose output is connected to the transmitting coil in the magnetic coupling coil. The secondary-side module includes a secondary-side compensation circuit and a secondary-side converter. The input of the secondary-side compensation circuit is connected to the receiving coil in the magnetic coupling coil, and its output is a DC voltage output through the secondary-side converter. The transmitting coil consists of two coils connected in series, while the receiving coil is a single coil.

[0046] The inverter comprises three bridge arms, each equipped with two switching transistors. One end of the first transmitting coil is connected to the node between the two switching transistors of the second bridge arm via a first compensation capacitor. One end of the second transmitting coil is connected to the node between the two switching transistors of the first bridge arm via a second compensation capacitor. The connection point between the first and second transmitting coils is connected to the node between the two switching transistors of the third bridge arm.

[0047] A controller (not shown in the figure) electrically connected to the inverter controls the inverter's on / off state by identifying the distance between the receiving coil and the two transmitting coils, ensuring that the transmitting coil with the smallest distance from the receiving coil transmits power. The controller identifies the distance between the coils by measuring the mutual inductance between the two coils.

[0048] Specifically, such as Figure 2 As shown, W1 and W2 are transmitting coils, and W3 is receiving coil. When the controller detects that the receiving coil is closest to the first transmitting coil, the controller turns on the switches of the second and third bridge arms and turns off the switch of the first bridge arm, so that power can be transferred through coupling between the first transmitting coil and the receiving coil.

[0049] When the controller detects that the receiving coil is closest to the second transmitting coil, the controller turns on the switching transistors of the first and third bridge arms and turns off the switching transistor of the second bridge arm, so that power can be transferred through the coupling of the second transmitting coil and the receiving coil.

[0050] When the controller detects that the distance difference between the receiving coil and the two transmitting coils is within a preset value, it turns on the switching transistors of the three bridge arms, and the first transmitting coil and the second transmitting coil are coupled to the receiving coil to transmit electrical energy.

[0051] By identifying the position of the receiving coil through the controller, various different working modes are formed, which amplifies the positional offset between the coil on the electronic product side and the coil on the charging dock side, making it convenient for users to charge effectively.

[0052] The switching frequencies of the transistors on all three bridge arms are the same, and the first transmitting coil and the first compensation capacitor satisfy... Resonance occurs when the first transmitting coil is inducted, C1 is the capacitance of the first compensation capacitor, and f is the switching frequency of the switching transistor.

[0053] The second transmitting coil and the second compensation capacitor satisfy the following conditions: Resonance occurs when the second transmitting coil is inducted, C2 is the capacitance of the second compensation capacitor, and f is the switching frequency of the switching transistor.

[0054] The first transmitting coil and the second transmitting coil are connected in series, and then connected to the first compensation capacitor and the second compensation capacitor, in accordance with the following conditions: Resonance occurs, where M is the mutual inductance between the two transmitting coils.

[0055] The switching frequency of the switching transistor can be adjusted in real time by the controller to ensure that the input impedance angle of the wireless charging system is always zero.

[0056] After resonance occurs, electrical energy can be transmitted from the transmitting coil to the receiving coil, which connects the electronic product end and the charging dock end. Subsequently, the power and efficiency of the power transmission need to be adjusted.

[0057] Specifically, such as Figure 1 and Figure 3 As shown, the bridge arm composed of switches S1 and S2 is phase-shifted relative to the bridge arm composed of switches S5 and S6, thus controlling the voltage at the midpoints a and c of the two bridge arms. The bridge arm composed of switches S3 and S4 is phase-shifted relative to the bridge arm composed of switches S5 and S6, thus controlling the voltage at the midpoints b and c of the two bridge arms. By adjusting the voltage values ​​across the coil, the power transmission can be increased or decreased.

[0058] While adjusting the phase shift of the bridge arm, the voltage across the coil can also be adjusted by controlling the duty cycle of the switching transistors on the bridge arm. Specifically, firstly, switching transistors S5 and S6 are turned on alternately, each with a duty cycle of 50%; then switching transistors S1 and S2 are turned on alternately, and their duty cycles are controlled to control the voltage at the midpoints a and c of the two bridge arms, i.e., the voltage across the second transmitting coil; finally, switching transistors S3 and S4 are turned on alternately, and their duty cycles are controlled to control the voltage at the midpoints b and c of the two bridge arms, i.e., the voltage across the first transmitting coil.

[0059] When two coils at the transmitting end are connected in series and operate together, to achieve higher power transmission efficiency, phase shift control of the bridge arm can be used to... Where v bc and v ac They are Figure 3 Chinese v bc and v ac The fundamental effective value; M 13 M is the mutual inductance between the first transmitting coil and the receiving coil. 23 Both are mutual inductances between the second transmitting coil and the receiving coil, and both are positive values.

[0060] This invention adjusts the voltage across the transmitting coil by phase shifting between bridge arms and the duty cycle of alternating switching transistors in the same bridge arm, thereby controlling the first transmitting coil, the second transmitting coil, or two transmitting coils connected in series to achieve high-efficiency power transmission.

[0061] This topology can be used not only in primary-side inverters, but also in secondary-side inverters of wireless charging systems, and can be used in both primary and secondary sides.

[0062] Example 2

[0063] like Figure 4 As shown, the topology of a wireless charging system according to the present invention includes a primary-side module, a secondary-side module, and a magnetically coupled coil. Compared with Embodiment 1, this embodiment further includes a common compensation element between the connection point of the first and second transmitting coils and the node between the two switching transistors of the third bridge arm. This common compensation element forms a self-resonant loop, enhancing the transmission efficiency of the transmitting coil. The common compensation element can be a capacitor or an inductor.

[0064] After adding the common compensation element, the first transmitting coil, the first compensation capacitor, and the common compensation element meet the following requirements: Resonance occurs at this time, where L1 is the self-inductance of the first transmitting coil, C1 is the capacitance of the first compensation capacitor, and X... 12 The reactance of the common compensation element is given by f, where f is the switching frequency of the switching transistor.

[0065] The second transmitting coil, the second compensation capacitor, and the common compensation element satisfy the following conditions: Resonance occurs at this time, where L2 is the self-inductance of the first transmitting coil, C2 is the capacitance of the first compensation capacitor, and X... 12 The reactance of the common compensation element is given by f, where f is the switching frequency of the switching transistor.

[0066] When the first transmitting coil operates alone, the switching transistors S3, S4, S5, and S6 form a full-bridge inverter; the switching signal of S1 is consistent with the switching signal of S5 and has a duty cycle of 50%, the switching signal of S2 is consistent with the switching signal of S6 and has a duty cycle of 50%, the first transmitting coil is connected to the input power supply, and the second transmitting coil, the second compensation capacitor, and the common compensation element form a self-resonant loop, which enhances the transmission efficiency of the first transmitting coil.

[0067] Similarly, when the second transmitting coil operates alone, the switching transistors S1, S2, S5, and S6 form a full-bridge inverter. The switching signal of S3 is consistent with the switching signal of S5 and has a duty cycle of 50%. The switching signal of S4 is consistent with the switching signal of S6 and has a duty cycle of 50%. The second transmitting coil is connected to the input power supply. The first transmitting coil, the first compensation capacitor, and the common compensation element form a self-resonant loop, which enhances the transmission efficiency of the second transmitting coil.

[0068] Example 3

[0069] like Figure 5 As shown, the topology of a wireless charging system according to the present invention includes a primary-side module, a secondary-side module, and a magnetically coupled coil. Compared with Embodiment 1, the inverter in the primary-side module includes two bridge arms, each with two switching transistors. The inverter also includes a capacitor bridge arm connected in parallel with the two bridge arms, comprising two capacitors C connected in series. dc1 and C dc2 .

[0070] One end of the first transmitting coil is connected to the node between the two switching transistors of the second bridge arm via the first compensation capacitor. One end of the second transmitting coil is connected to the node between the two switching transistors of the first bridge arm via the second compensation capacitor. The connection point between the first and second transmitting coils is connected to the node between the two capacitors of the capacitor bridge arm.

[0071] During power transmission, switching transistors S1 and S2 are turned on alternately, and the voltage at the midpoints a and c of the bridge arm is adjusted by controlling the duty cycle of S1 and S2. Similarly, switching transistors S3 and S4 are turned on alternately, and the voltage at the midpoints b and c of the bridge arm is adjusted by controlling the duty cycle of S3 and S4. By adjusting the voltage across the coil, the power transmission can be increased or decreased.

[0072] In low-power electronic products, a capacitor bridge arm can be used to replace the original bridge arm, reducing the power transmission power to meet the needs of low-power electronic products and also reducing the cost of the wireless charging system.

[0073] This topology can be used not only in primary-side inverters, but also in secondary-side inverters of wireless charging systems, and can be used in both primary and secondary sides.

[0074] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. A topology for a wireless charging system, characterized in that, include: Primary-side module, wherein an inverter is provided in the primary-side module; Secondary side module; The magnetic coupling coil includes a transmitter coil connected to the output terminal of the inverter and a receiver coil connected to the input terminal of the secondary module. The transmitting coil has two transmitting coils connected in series, and the receiving coil is a single coil; the controller, which is electrically connected to the inverter, identifies the distance between the receiving coil and the two transmitting coils and controls the switching on and off of the inverter so that the transmitting coil with the smallest distance from the receiving coil can transmit electrical energy. The distance between the receiving coil and the transmitting coil is determined based on the mutual inductance between them. When the controller detects that the distance difference between the receiving coil and the two transmitting coils is within a preset value, the two transmitting coils are connected in series and coupled together with the receiving coil to transmit electrical energy. When the first and second transmitting coils are connected in series and work together, they are in harmony with the first and second compensation capacitors, provided that... Resonance occurs, allowing electrical energy to be transferred from the transmitting coil to the receiving coil; Where M is the mutual inductance of the two transmitting coils, L1 is the self-inductance of the first transmitting coil, C1 is the capacitance of the first compensation capacitor, L2 is the self-inductance of the second transmitting coil, C2 is the capacitance of the second compensation capacitor, and f is the switching frequency of the switching transistor.

2. The topology of the wireless charging system according to claim 1, characterized in that, The inverter includes three bridge arms, each of which is equipped with two switching transistors; one end of the first transmitting coil is connected to the node between the two switching transistors of the second bridge arm via a first compensation capacitor, one end of the second transmitting coil is connected to the node between the two switching transistors of the first bridge arm via a second compensation capacitor, and the connection point between the first and second transmitting coils is connected to the node between the two switching transistors of the third bridge arm.

3. The topology of the wireless charging system according to claim 2, characterized in that, When the controller detects that the receiving coil is closest to the first transmitting coil, the controller turns on the switching transistors of the second and third bridge arms and turns off the switching transistor of the first bridge arm, so that power can be transferred through the coupling of the first transmitting coil and the receiving coil. When the controller detects that the receiving coil is closest to the second transmitting coil, the controller turns on the switching transistors of the first and third bridge arms and turns off the switching transistor of the second bridge arm, so that power can be transferred through the coupling of the second transmitting coil and the receiving coil. When the controller detects that the distance difference between the receiving coil and the two transmitting coils is within a preset value, it turns on the switching transistors of the three bridge arms, and the first transmitting coil and the second transmitting coil are coupled to the receiving coil to transmit electrical energy.

4. The topology of the wireless charging system according to claim 3, characterized in that, The switching frequencies of the switching transistors are all the same, and the first transmitting coil and the first compensation capacitor satisfy the following conditions: Resonance occurs when the first transmitting coil is inducted, C1 is the capacitance of the first compensation capacitor, and f is the switching frequency of the switching transistor. The second transmitting coil and the second compensation capacitor satisfy the following conditions: Resonance occurs when the second transmitting coil is inducted, C2 is the capacitance of the second compensation capacitor, and f is the switching frequency of the switching transistor.

5. The topology of the wireless charging system according to claim 4, characterized in that, The switching frequency of the switching transistor can be adjusted in real time by the controller, so that the input impedance angle of the wireless charging system is always zero.

6. The topology of the wireless charging system according to claim 3, characterized in that, A common compensation element is provided between the connection point of the first transmitting coil and the second transmitting coil and the node between the two switching transistors of the third bridge arm.

7. The topology of the wireless charging system according to claim 6, characterized in that, The switching frequencies of all the switching transistors are the same; The first transmitting coil, the first compensation capacitor, and the common compensation element satisfy the following conditions: Resonance occurs at this time, where L1 is the self-inductance of the first transmitting coil, C1 is the capacitance of the first compensation capacitor, and X... 12 The reactance of the common compensation element is given by f, where f is the switching frequency of the switching transistor. The second transmitting coil, the second compensation capacitor, and the common compensation element satisfy the following conditions: Resonance occurs at this time, where L2 is the self-inductance of the first transmitting coil, C2 is the capacitance of the first compensation capacitor, and X... 12 The reactance of the common compensation element is given by f, where f is the switching frequency of the switching transistor.

8. The topology of the wireless charging system according to claim 1, characterized in that, The inverter includes two bridge arms, each of which is equipped with two switching transistors; the inverter also includes a capacitor bridge arm connected in parallel with the two bridge arms, the capacitor bridge arm including two capacitors connected in series. One end of the first transmitting coil is connected to the node between the two switching transistors of the second bridge arm via the first compensation capacitor. One end of the second transmitting coil is connected to the node between the two switching transistors of the first bridge arm via the second compensation capacitor. The connection point between the first and second transmitting coils is connected to the node between the two capacitors of the capacitor bridge arm.

9. The topology of the wireless charging system according to claim 2 or 8, characterized in that, The three-arm structure of the inverter can be used as a secondary inverter for a wireless charging system or as a primary-secondary dual-side inverter.

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