A multi-capacitance current-sharing compensation circuit for a wireless charging receiving coil

Abstract

The utility model discloses a kind of multi-capacitance current-sharing compensation circuit of wireless charging receiving coil, comprising: multiple parallelly connected current-sharing compensation units, the receiving end of the current-sharing compensation unit is magnetically coupled with wireless transmitting unit, the output end of the current-sharing compensation unit is connected with a rectifier unit, multiple the current-sharing compensation unit is used to realize the current balance of each branch of wireless charging receiving coil.The utility model is simple in structure, can effectively realize current-sharing, improve the safety, efficiency and reliability of large-current wireless charging system, reduce the coil temperature rise.

Description

Technical Field

[0001] This utility model relates to the field of wireless power transmission technology, specifically to a multi-capacitor current sharing compensation circuit for a wireless charging receiving coil. Background Technology

[0002] Magnetic-coupled resonant wireless power transfer technology is widely used in high-power charging scenarios such as electric vehicles and mobile robots. To increase the system's transmission power and rated current, the receiving coil needs to carry a large current. In existing technologies, multiple wires are often wound in parallel to increase the current-carrying capacity of the receiving coil.

[0003] However, when multiple conductors are wound in parallel, their self-inductance and mutual inductance with other conductors are not entirely the same due to differences in their spatial positions. Furthermore, the AC resistance of each conductor may also vary. This results in uneven distribution of the total current in the parallel conductor branches during system operation, a phenomenon known as current imbalance. Under different coupling mechanisms, the current amplitude difference between branches can reach 2-3 times or even higher. When the current in some conductors is too high, exceeding their safe current-carrying capacity, it can lead to localized overheating or even damage, reducing system reliability and safety. Secondly, conductor utilization is low, with some conductors carrying current far below their rated value, resulting in material waste, increased overall losses, reduced system transmission efficiency, and increased difficulty in conductor selection.

[0004] Therefore, overcoming the current imbalance caused by differences in internal inductance and mutual inductance is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0005] To solve the above-mentioned technical problems, this utility model proposes the following technical solution:

[0006] In a first aspect, this utility model provides a multi-capacitor current sharing compensation circuit for a wireless charging receiving coil, comprising: multiple current sharing compensation units connected in parallel, wherein the receiving end of each current sharing compensation unit is magnetically coupled to a wireless transmitting unit, and the output end of each current sharing compensation unit is connected to a rectifier unit, wherein the multiple current sharing compensation units are used to achieve current balancing in each branch of the wireless charging receiving coil.

[0007] In one possible implementation, the current sharing compensation unit includes: a receiving coil wound with a wire, and a current sharing compensation capacitor connected in series with the receiving coil, wherein the receiving coil and the current sharing compensation capacitor form a resonant compensation circuit; the receiving coil is magnetically coupled to the wireless transmitting unit, a first end of the receiving coil is electrically connected to a first end of the current sharing compensation capacitor, and a second end of the receiving coil and a second end of the current sharing compensation capacitor are both electrically connected to the rectifier unit.

[0008] In one possible implementation, the size of the current sharing compensation capacitor in each current sharing compensation unit is different.

[0009] In one possible implementation, the receiving coil is wound with Litz wire.

[0010] In one possible implementation, the wireless transmitting unit includes a transmitting coil that is magnetically coupled to a receiving coil. A first end of the transmitting coil is electrically connected to a first end of a first capacitor. The second end of the first capacitor and the second end of the transmitting coil are both electrically connected to the output of a high-frequency inverter bridge. The input of the high-frequency inverter bridge is electrically connected to the positive and negative terminals of a power supply.

[0011] In one possible implementation, the rectifier unit includes a rectifier bridge, the input terminals of which are electrically connected to the second terminal of the current sharing compensation capacitor and the second terminal of the receiving coil, respectively, and the output terminals of the rectifier bridge are connected in parallel with the second capacitor and the first resistor, respectively.

[0012] In one possible implementation, the receiving coil includes a planar helical coil, a three-dimensional solenoid coil, and a flexible deformable coil.

[0013] Secondly, embodiments of this application provide a wireless charging device that employs a multi-capacitor current sharing compensation circuit for the wireless charging receiving coil in any possible implementation.

[0014] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0015] This invention constructs a structure of multiple independent resonant compensation units connected in parallel by independently configuring a series-connected, specially designed current-sharing compensation capacitor for each current-sharing compensation unit of the receiving coil. By precisely selecting the capacitance value of each current-sharing compensation capacitor, the differences in self-inductance and mutual inductance of each branch are effectively compensated, and the current is forced to be evenly distributed in each parallel conductor, thus solving the problem of current imbalance.

[0016] The circuit designed using this utility model can avoid the risk of local overheating caused by excessive current in a single conductor, improve the overall current resistance of the coil and the safety and stability of the system operation, make the current distribution more uniform, reduce the overall conductor loss, and help improve the transmission efficiency of the system. At the same time, it avoids local hot spots, resulting in a lower overall temperature rise and more uniform temperature distribution of the coil. After achieving current sharing, the conductor specifications can be selected according to the principle of average distribution of total current and number of branches, simplifying the design process. Attached Figure Description

[0017] Figure 1 A schematic diagram of the overall structure of the multi-capacitor current sharing compensation circuit for the wireless charging receiving coil provided in this embodiment of the utility model. Detailed Implementation

[0018] The present solution will now be described in conjunction with the accompanying drawings and specific embodiments.

[0019] Figure 1 A schematic diagram of the overall structure of a multi-capacitor current sharing compensation circuit for a wireless charging receiving coil provided in this application embodiment is shown below. Figure 1 This embodiment of a multi-capacitor current sharing compensation circuit for a wireless charging receiving coil includes: multiple current sharing compensation units connected in parallel; the receiving end of the current sharing compensation unit is magnetically coupled to a wireless transmitting unit; the output end of the current sharing compensation unit is connected to a rectifier unit; and the multiple current sharing compensation units are used to achieve current balancing in each branch of the wireless charging receiving coil.

[0020] In this embodiment, three current sharing compensation units are used. Each current sharing compensation unit includes: a receiving coil wound with wire, a current sharing compensation capacitor connected in series with the receiving coil, the receiving coil and the current sharing compensation capacitor forming a resonant compensation circuit, the receiving coil being magnetically coupled to the wireless transmitting unit, the first end of the receiving coil being electrically connected to the first end of the current sharing compensation capacitor, and the second end of the receiving coil and the second end of the current sharing compensation capacitor being electrically connected to the rectifier unit. The wireless transmitting unit includes a transmitting coil Lp, which is magnetically coupled to the receiving coil. The first end of the transmitting coil Lp is electrically connected to the first end of the first capacitor Cp, and the second end of the first capacitor Cp and the second end of the transmitting coil Lp are both electrically connected to the output terminal of the high-frequency inverter bridge. The input terminal of the high-frequency inverter bridge is electrically connected to the positive and negative terminals of the power supply. The rectifier unit includes a rectifier bridge, the input terminal of which is electrically connected to the second end of the current sharing compensation capacitor and the second end of the receiving coil, respectively, and the output terminal of the rectifier bridge is connected to the second capacitor and the first resistor R, respectively. L Parallel connection.

[0021] In this embodiment, the current sharing compensation capacitor in each current sharing compensation unit has a different value. Each capacitor value is determined based on the self-inductance of each corresponding current sharing compensation unit, the mutual inductance between each compensation circuit, and the operating angular frequency.

[0022] Secondly, embodiments of this application provide a wireless charging device, including a housing, a multi-capacitor current sharing compensation circuit for a wireless charging receiving coil disposed within the housing, and an output interface for powering devices such as electric vehicles and mobile robots.

[0023] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0024] The above description is merely a specific embodiment of this utility model. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model. The protection scope of this utility model should be determined by the scope of the claims.

Claims

1. A multi-capacitor current sharing compensation circuit for a wireless charging receiving coil, characterized in that, include: Multiple current sharing compensation units are connected in parallel. The receiving end of each current sharing compensation unit is magnetically coupled to the wireless transmitting unit, and the output end of each current sharing compensation unit is connected to a rectifier unit. The multiple current sharing compensation units are used to achieve current balancing in each branch of the wireless charging receiving coil.

2. The multi-capacitor current sharing compensation circuit for the wireless charging receiving coil according to claim 1, characterized in that, The current sharing compensation unit includes: a receiving coil wound with a wire, and a current sharing compensation capacitor connected in series with the receiving coil, wherein the receiving coil and the current sharing compensation capacitor form a resonant compensation circuit; the receiving coil is magnetically coupled to the wireless transmitting unit, the first end of the receiving coil is electrically connected to the first end of the current sharing compensation capacitor, and the second end of the receiving coil and the second end of the current sharing compensation capacitor are both electrically connected to the rectifier unit.

3. The multi-capacitor current sharing compensation circuit for the wireless charging receiving coil according to claim 2, characterized in that, The size of the current sharing compensation capacitor in each current sharing compensation unit is different.

4. The multi-capacitor current sharing compensation circuit for the wireless charging receiving coil according to claim 2, characterized in that, The receiving coil is wound with Litz wire.

5. The multi-capacitor current sharing compensation circuit for the wireless charging receiving coil according to claim 1, characterized in that, The wireless transmitting unit includes a transmitting coil, which is magnetically coupled to a receiving coil. The first end of the transmitting coil is electrically connected to the first end of a first capacitor. The second end of the first capacitor and the second end of the transmitting coil are both electrically connected to the output end of a high-frequency inverter bridge. The input end of the high-frequency inverter bridge is electrically connected to the positive and negative terminals of a power supply.

6. The multi-capacitor current sharing compensation circuit for the wireless charging receiving coil according to claim 2, characterized in that, The rectifier unit includes a rectifier bridge. The input terminal of the rectifier bridge is electrically connected to the second terminal of the current sharing compensation capacitor and the second terminal of the receiving coil, respectively. The output terminal of the rectifier bridge is connected in parallel with the second capacitor and the first resistor, respectively.

7. The multi-capacitor current sharing compensation circuit for the wireless charging receiving coil according to claim 2, characterized in that, The receiving coil includes a planar helical coil, a three-dimensional solenoid coil, and a flexible deformable coil.

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