Wireless power transmission system for double loads

Abstract

The invention relates to a wireless electric energy transmission system for double loads, which is characterized by comprising a transmitting end for transmitting wireless electric energy to a first electric load and a second electric load, and a first receiving end and a second receiving end for receiving the wireless electric energy and respectively supplying power to the first electric load and the second electric load, the transmitting end, the first receiving end and the second receiving end are respectively provided with a transmitting coil, a first receiving coil and a second receiving coil, and every two of the transmitting coil, the first receiving coil and the second receiving coil are magnetically coupled. According to the invention, wireless power supply of the two loads is realized, and the anti-offset performance of the energy transmitting end and the energy receiving end of the wireless power transmission system is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of wireless power transmission, and in particular to a wireless power transmission system for dual loads. Background Art

[0002] Currently, desktop monitors typically use wired power supplies, which inevitably clutter the desktop with numerous cables, leading to potential safety hazards such as leakage and electric shock. Wireless charging can effectively address this issue. For example, a power transmitter placed on the desktop can power a power receiver built into the desktop monitor via a magnetic field, enabling wireless power transmission across the monitor.

[0003] However, the inventors of this application have found in their research that existing wireless power transmission systems generally have the following problems:

[0004] (1) The existing wireless power transmission system can only power one electrical load. When two electrical loads need to be powered, two wireless power transmission systems are required, which increases the user's equipment cost. Taking the aforementioned desktop monitor scenario as an example, if the wireless power transmission system can not only power the monitor, but also power other small electronic devices of the user, such as mobile phones, it will greatly save the user's equipment purchase and space placement costs, and greatly improve the user's user experience;

[0005] (2) Existing wireless power transmission systems have poor anti-deviance performance between the transmitting and receiving ends of the power. That is, in existing wireless power transmission systems, the coils at the transmitting and receiving ends usually need to be aligned within a certain range or angle. This range or angle is usually small. When this range or angle is exceeded, the charging efficiency of the power load device is low. Summary of the Invention

[0006] In response to the above problems, the purpose of the present invention is to provide a wireless power transmission system for dual loads, which can realize wireless power supply of two loads based on one system and improve the anti-deviation performance of the energy transmitting end and the energy receiving end of the wireless power transmission system.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present application provides a wireless power transmission system for dual loads, comprising: a transmitting end for transmitting wireless power to a first power load and a second power load, a first receiving end and a second receiving end for receiving wireless power and supplying power to the first power load and the second power load, respectively;

[0009] The transmitting end, the first receiving end and the second receiving end respectively have a transmitting coil, a first receiving coil and a second receiving coil, and magnetic coupling is formed between the transmitting coil, the first receiving coil and the second receiving coil.

[0010] In one implementation of the present application, the circuit loop of the transmitting end includes:

[0011] DC power supply;

[0012] An inverter connected to both ends of the DC power supply to convert the DC signal into an AC signal;

[0013] a harmonic suppression circuit connected to the dual-port output of the inverter and connected to both ends of the transmitting coil;

[0014] and the transmitting coil.

[0015] In one implementation of the present application, the inverter adopts a full-bridge converter composed of four MOSFETs.

[0016] In one implementation of the present application, the harmonic suppression circuit adopts an LCC compensation circuit.

[0017] In one implementation of the present application, the circuit loop of the first receiving end includes: a first receiving coil and a first compensation capacitor connected in series; a first rectifier bridge connected across the first receiving coil and the first compensation capacitor connected in series; a first voltage stabilizing circuit connected between an output port of the first rectifier bridge and across a first electrical load; and a first filter circuit connected to an input and an output of the first voltage stabilizing circuit.

[0018] The circuit loop of the second receiving end includes: a second receiving coil and a second compensation capacitor connected in series; a second rectifier bridge connected across the second receiving coil and the second compensation capacitor connected in series; a second voltage stabilizing circuit connected between the output port of the second rectifier bridge and the second electrical load; and a second filter circuit connected to the input and output ends of the second voltage stabilizing circuit.

[0019] In one implementation of the present application, the transmitting coil includes four unit coils forming a grid pattern, the current direction of each unit coil is the same, and the cross-sectional size of each unit coil is the same; the four unit coils are connected in series in a clockwise or counterclockwise direction.

[0020] In one implementation of the present application, the transmitting coil further includes a transmitting coil magnetic core arranged on one side of the four unit coils.

[0021] In one implementation of the present application, the first receiving coil is a square coil; and a side length of the first receiving coil is greater than a side length of one of the unit coils, but less than a sum of side lengths of two unit coils.

[0022] In an implementation of the present application, the second receiving coil includes a square coil, and the side length of the second receiving coil is smaller than the side length of a unit coil.

[0023] In one implementation of the present application, the second receiving coil further includes a receiving end magnetic core arranged on one side of the square coil.

[0024] The present invention has the following advantages due to the adoption of the above technical solution:

[0025] 1) The wireless power transmission system can provide power to two electrical loads.

[0026] 2) The magnetic coupling mechanism (transmitting coil, first receiving coil and second receiving coil) of the wireless power transmission system has a relatively stable mutual inductance value when relative offset occurs, thereby improving the anti-offset performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic diagram of the overall circuit structure of a wireless power transmission system for dual loads in an embodiment of the present application;

[0028] Figure 2 is Figure 1 Schematic diagram of the obtained mutual inductance model;

[0029] Figure 3a is a schematic diagram of the relative relationship between the transmitting coil, the first receiving coil and the second receiving coil in a detailed embodiment of the present application;

[0030] Figure 3b Schematic diagram of the relative size relationship between the transmitting coil and the first receiving coil;

[0031] Figures 4a to 4c is a schematic diagram of the relative sizes and position offsets of the first receiving coil and the second receiving coil in a detailed embodiment of the present application;

[0032] Figure 5 This is a curve of different offset distances and mutual inductance values in a calculation example;

[0033] Figure 6a is the voltage and current waveform of the electrical load 1 in the calculation example;

[0034] Figure 6b is the voltage and current waveform of the electrical load 2 in the calculation example;

[0035] Figure 6cThis is the voltage and current waveform of the electrical load 1 in the example when it is offset;

[0036] Figure 6d Figure 2 is the voltage and current waveform of the electrical load 2 in an example when it is offset. DETAILED DESCRIPTION

[0037] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the described embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field are within the scope of protection of the present invention.

[0038] In view of the problem that the existing technology urgently needs to provide a wireless power transmission system that can supply power to two loads and improve the anti-deviation performance. The technical solution of the present invention accordingly provides a wireless power transmission system for two loads, including: a transmitting end that transmits wireless power to a first power load and a second power load, a first receiving end and a second receiving end that receive wireless power and supply power to the first power load and the second power load respectively; the transmitting end, the first receiving end and the second receiving end respectively have a transmitting coil, a first receiving coil and a second receiving coil, and the transmitting coil, the first receiving coil and the second receiving coil are magnetically coupled with each other. This solution realizes wireless power supply for two loads and improves the anti-deviation performance of the energy transmitting end and the energy receiving end of the wireless power transmission system.

[0039] Please refer to more drawings of the embodiments of the present invention, in which the system provided by the present invention is further explained in more detailed embodiments of the present invention.

[0040] like Figure 1 , the circuit topology of the system mainly includes a transmitting end and a receiving end, wherein the receiving end includes a first receiving end ( Figure 1 In the figure, it is shown as receiving end 1) and the second receiving end ( Figure 1 The figure shows the receiving end 2).

[0041] In an application scenario where a wireless power transmission system is used to power a desktop monitor and a mobile phone, the transmitter can be placed on a desktop or built into a desktop, the receiver 1 is integrated into the base of the desktop monitor, and the receiver 2 is integrated into the mobile phone, thereby achieving the purpose of collaborative power supply from one transmitter to two receivers.

[0042] The system specifically includes: a transmitting end that transmits wireless power to a first electrical load and a second electrical load, and a first receiving end and a second receiving end that receive wireless power and respectively power the first electrical load and the second electrical load; the transmitting end, the first receiving end, and the second receiving end respectively have a transmitting coil, a first receiving coil, and a second receiving coil, and the transmitting coil, the first receiving coil, and the second receiving coil are magnetically coupled to each other.

[0043] like Figure 1 The circuit loop of the transmitting end includes: a DC power supply; an inverter connected to both ends of the DC power supply to convert the DC signal into an AC signal; a harmonic suppression circuit connected to the dual-port output of the inverter and connected to both ends of the transmitting coil; and the transmitting coil.

[0044] More specifically, the DC power supply is U bus The inverter adopts a full-bridge converter (composed of MOSFET Q1 to Q4); the harmonic suppression circuit adopts an LCC compensation circuit (i.e., the inductor L p , capacitor C p and capacitor C1). The transmitting coil is L1.

[0045] like Figure 1 The circuit loop of the first receiving end includes: a first receiving coil and a first compensation capacitor connected in series; a first rectifier bridge connected across the first receiving coil and the first compensation capacitor connected in series; a first voltage stabilizing circuit connected between the output port of the first rectifier bridge and the first power load; and a first filter circuit connected to the input and output ends of the first voltage stabilizing circuit.

[0046] More specifically, the first receiving coil L of the first receiving end 21 With compensation capacitor C 21 The rectifier bridge is connected in series. 11 ~D 41 The first voltage regulator circuit is a Buck converter, including MOSFET Q B1 and diode D B1 ; The filter circuit includes filter capacitor C o1 , filter inductor L B1 and filter capacitor C B1 The first receiving end is the first electrical load R o1 Power supply, which can be a load equivalent to a desktop monitor, for example.

[0047] The circuit structure of the second receiving end is similar to that of the first receiving end, and will not be repeated.

[0048] The working principle of the above circuit topology is:

[0049] The DC power supply's output voltage passes through a full-bridge inverter, converting it to 85kHz AC (this frequency can be adjusted depending on the system). After passing through an LCC compensation topology, it is emitted from the transmitter coil in the form of an alternating magnetic field. Receiver 1 receives the energy from the transmitter via electromagnetic induction, undergoes series compensation, and then undergoes full-bridge rectification / filtering and a buck converter to step down the voltage before supplying power to the desktop monitor. Receiver 2 receives the relayed energy from receiver 1 via electromagnetic induction, undergoes series compensation, and then undergoes full-bridge rectification / filtering and a buck converter to step down the voltage before supplying power to the smartphone. The circuit's control system components monitor and control the output voltage and current during this process to maintain constant voltage and protect the circuit from abnormal conditions such as short circuits and overcurrent.

[0050] Figure 2 is the mutual inductance model of the circuit topology proposed in the present invention. s is the equivalent output voltage source of the full-bridge inverter, I 1p is the current flowing through the inductor Lp, i1 is the current flowing through the inductor L1. M1 is the mutual inductance between the transmitter and the receiver 1; M2 is the mutual inductance between the transmitter and the receiver 2. 12 is the mutual inductance between the two receiving ends. 21 is the L flowing through the receiving end 1 21 The current; i 22 is the L flowing through the receiving end 2 22 The current. R e1 and R e2 They are the AC equivalent loads of receiving ends 1 and 2 after impedance adjustment by the rectifier bridge and Buck converter.

[0051] Combine Figure 2 Expand the formula derivation and theoretical analysis, and we can get from Kirchhoff's law:

[0052]

[0053] From the resonance relationship:

[0054]

[0055] Substituting (2) into (1), we get

[0056]

[0057] Solving the above formula we can get

[0058]

[0059]

[0060] Convert to valid value form

[0061]

[0062] From the above formula, we can know that: o1 and R o2 The current I o1 and I o2 It is related to the load size, power supply voltage and mutual inductance. When the system parameters (DC input voltage, system operating frequency and mutual inductance value, etc.) are determined, R o1 and R o2 If the load is expected to obtain relatively stable power when the secondary coil moves, the change in mutual inductance should be minimized to improve the anti-drift performance of the wireless charging system.

[0063] In order to ensure that the magnetic coupling mechanism has a relatively stable mutual inductance value when an offset occurs, this embodiment proposes a "grid-shaped" magnetic coupling mechanism, as shown in 3a.

[0064] Among them, the transmitting coil includes four unit coils (unit coil 1 to unit coil 4 in the figure) forming a grid. The current direction of each unit coil is the same, and the cross-sectional size of each unit coil is the same; the four unit coils are connected in series in a clockwise or counterclockwise direction, which not only reduces the edge effect to a certain extent, but also generates a more stable magnetic field.

[0065] The transmitting coil also includes a transmitting coil magnetic core arranged on one side of the four unit coils.

[0066] like Figure 3b The first receiving coil (receiving coil 1 in the figure) is a square coil. Its side length is greater than the side length of one of the unit coils, but less than the sum of the side lengths of the two unit coils. This asymmetric structure helps improve the anti-deviating performance of the magnetic coupling mechanism.

[0067] See Figure 3a ,and Figures 4a to 4c The second receiving coil (illustrated as receiving coil 2 in the figure) comprises a square coil, and the side length of the second receiving coil is smaller than the side length of a single unit coil. The second receiving coil also includes a receiving core (labeled as receiving core 2 in the figure) positioned on one side of the square coil. Receiving coil 2 can be placed anywhere within receiving coil 1 without affecting the power characteristics of receiving coil 2.

[0068] The above system is measured in an example below.

[0069] The specific electrical parameters of the system are shown in Table 1:

[0070]

[0071] Table 1

[0072] When the "Tianzi grid" magnetic coupling mechanism has an offset distance in the x-axis and y-axis directions, the offset distance is related to M1, M2 and M 12 The simulation results are as follows Figure 5 As shown. Taking the offset distance of ±50mm in the x-axis direction as an example, the fluctuation ranges of M1 and M2 are 27μH~32μH and 0~7μH respectively. At the same time, since the positions of the receiving end coil 1 and the receiving end coil 2 are relatively fixed, M 12 Maintained at around 40μH. On the one hand, the energy of the receiving end coil 1 mainly comes from the transmitting coil, and the energy of the receiving end coil 2 mainly comes from the receiving end coil 1 (in other words, the receiving end coil 1 acts as an energy relay to power the receiving end coil 2); on the other hand, due to the 12 As the distance changes, the power received by receivers 1 and 2 remains relatively stable. Similarly, the situation with offset along the y-axis is similar. Therefore, this magnetic coupling mechanism can transmit relatively stable power within the central 100*100mm range.

[0073] The system operating frequency was selected as 85kHz, and the DC power supply voltage was 24V. To simulate actual conditions, a rectifier bridge and a buck-type DC-DC circuit were installed at each receiving end, and a controller was designed for voltage regulation. The receiving end had a voltage of 12V and a current of 4A, simulating a computer display. The second receiving coil had an output voltage of 5V and a current of 2.5A, simulating a mobile phone charger. Figures 6a to 6d The circuit simulation shows the voltage and current waveforms of the two loads when the secondary terminals are fully aligned. It can be seen that both loads reach their rated voltages, indicating that the magnetic coupling mechanism can meet the requirements of wirelessly charging two loads simultaneously.

[0074] In summary, the system provided by the embodiments of the present application realizes:

[0075] 1) The wireless power transmission system can provide power to two electrical loads.

[0076] 2) The magnetic coupling mechanism (transmitting coil, first receiving coil and second receiving coil) of the wireless power transmission system has a relatively stable mutual inductance value when relative offset occurs, thereby improving the anti-offset performance.

[0077] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0078] In the several embodiments provided by the present invention, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the above units is merely a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0079] The above-mentioned integrated unit implemented in the form of a software functional unit can be stored in a computer-readable storage medium. The above-mentioned software functional unit is stored in a storage medium and includes a number of instructions for causing a computer device (which can be a personal computer, server, or network device, etc.) or a processor to perform some of the steps of the above-mentioned methods of various embodiments of the present invention. The aforementioned storage medium includes: a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk, etc., various media that can store program code.

[0080] The above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A wireless power transmission system for dual loads, characterized in that: include: a transmitting end for transmitting wireless power to a first power load and a second power load, and a first receiving end and a second receiving end for receiving wireless power and supplying power to the first power load and the second power load respectively; The transmitting end, the first receiving end and the second receiving end respectively have a transmitting coil, a first receiving coil and a second receiving coil, and magnetic coupling is formed between the transmitting coil, the first receiving coil and the second receiving coil.

2. The wireless power transmission system for dual loads according to claim 1, characterized in that: The circuit loop of the transmitting end includes: DC power supply; An inverter connected to both ends of the DC power supply to convert the DC signal into an AC signal; a harmonic suppression circuit connected to the dual-port output of the inverter and connected to both ends of the transmitting coil; and the transmitting coil.

3. The wireless power transmission system for dual loads according to claim 2, characterized in that: The inverter adopts a full-bridge converter composed of four MOSFETs.

4. The wireless power transmission system for dual loads according to claim 2, characterized in that: The harmonic suppression circuit adopts an LCC compensation circuit.

5. The wireless power transmission system for dual loads according to claim 1, characterized in that: The circuit loop of the first receiving end includes: a first receiving coil and a first compensation capacitor connected in series; a first rectifier bridge connected across the first receiving coil and the first compensation capacitor connected in series; a first voltage stabilizing circuit connected between the output port of the first rectifier bridge and the first power load; and a first filter circuit connected to the input and output ends of the first voltage stabilizing circuit; The circuit loop of the second receiving end includes: a second receiving coil and a second compensation capacitor connected in series; a second rectifier bridge connected across the second receiving coil and the second compensation capacitor connected in series; a second voltage stabilizing circuit connected between the output port of the second rectifier bridge and the second electrical load; and a second filter circuit connected to the input and output ends of the second voltage stabilizing circuit.

6. The wireless power transmission system for dual loads according to claim 1, characterized in that: The transmitting coil includes four unit coils forming a grid pattern, the current direction of each unit coil is the same, and the cross-section size of each unit coil is the same; the four unit coils are connected in series in a clockwise or counterclockwise direction.

7. The wireless power transmission system for dual loads according to claim 6, characterized in that: The transmitting coil further includes a transmitting coil magnetic core arranged on one side of the four unit coils.

8. The wireless power transmission system for dual loads according to claim 6, characterized in that: The first receiving coil is a square coil; and the side length of the first receiving coil is greater than the side length of one of the unit coils, but less than the sum of the side lengths of the two unit coils.

9. The wireless power transmission system for dual loads according to claim 8, characterized in that: The second receiving coil includes a square coil, and a side length of the second receiving coil is smaller than a side length of one unit coil.

10. The wireless power transmission system for dual loads according to claim 9, characterized in that: The second receiving coil further includes a receiving end magnetic core arranged on one side of the square coil.

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