A wireless energy transfer system and method of energy transfer

Abstract

The application relates to a wireless energy transmission system and an energy transmission method, the system comprising: an energy source and n-stage relay units arranged on the same horizontal line; a first-stage relay unit in the n-stage relay units is connected with an output end of the energy source; the first-stage relay unit in the n-stage relay units is used for receiving energy transmitted by the energy source and transmitting the energy to a next-stage relay unit; non-contact energy transmission is realized between each stage of the n-stage relay units in a resonance mode; and n is a positive integer greater than 2. The wireless energy transmission system provided by the application can not only improve power transmission efficiency but also meet high insulation requirements and ensure power supply safety.

Description

Technical Field

[0001] This invention relates to the field of flexible power transmission, and more specifically to a wireless power transmission system and a power transmission method. Background Technology

[0002] In flexible AC transmission systems, high-voltage, high-power power electronic devices typically require multiple power electronic switching devices connected in series to the busbar to support the high busbar voltage. However, the driving power supplies for these power electronic switching devices need to be effectively isolated. Unlike traditional methods, wireless power transmission technology transmits energy through magnetic or electric fields without direct contact, thus significantly improving the system's insulation level. Therefore, it is suitable for providing isolated power supplies for the power electronic switching devices in flexible AC transmission systems.

[0003] Traditional wireless power transfer systems use only one transmitting coil and one receiving coil. This single-path power transfer method is unsuitable for flexible AC transmission systems that require powering multiple loads. Therefore, a system using multiple repeater coils for wireless power transfer is needed to power multiple loads. However, in this type of wireless power transfer system, the energy received by each load is related to the load's resistance, and the power regulation of each load is coupled, which makes power control of the loads difficult. Summary of the Invention

[0004] In view of the shortcomings of existing technologies, this invention improves power transmission efficiency, meets high insulation requirements, and ensures power supply safety.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] An improvement of a wireless power transmission system is that the system includes: an energy source and n-level relay units arranged on the same horizontal line;

[0007] The first-level relay unit in the n-level relay unit is connected to the output end of the energy source;

[0008] The first-level relay unit in the n-level relay unit is used to receive the energy sent by the energy source and transmit the energy to the next-level relay unit;

[0009] In the n-level relay unit, each level of relay unit performs non-contact energy transfer through resonance.

[0010] Where n is a positive integer greater than 2.

[0011] Preferably, the distance between each relay unit in the n-level relay unit is equal.

[0012] Preferably, the relay unit includes: a first energy closed loop, a ferrite, and a second energy closed loop arranged sequentially on the same horizontal line.

[0013] Furthermore, the first energy closed-loop circuit consists of a first relay coil and a capacitor connected to the first relay coil;

[0014] The second energy closed-loop circuit consists of a second relay coil, a capacitor, and a load connected in sequence;

[0015] The first relay coil is used to transfer the received energy to the second relay coil via resonance;

[0016] The second relay coil is used to provide energy to the load in the flexible AC system and to transfer the remaining energy to the first relay coil of the next-level relay unit through resonance.

[0017] Furthermore, the ferrite is placed at the midpoint between the first energy closed loop and the second energy closed loop.

[0018] Furthermore, the first relay coil and the second relay coil adopt a bipolar coil structure.

[0019] Preferably, the energy source consists of a DC bus voltage and an H-bridge inverter connected to the DC bus voltage.

[0020] Furthermore, the H-bridge inverter includes:

[0021] First MOSFET, first diode D1, second MOSFET, second diode D2, third MOSFET, third diode D3, fourth MOSFET, fourth diode D4;

[0022] The drain of the first MOSFET is connected to the cathode of the first diode D1;

[0023] The drain of the second MOSFET is connected to the cathode of the second diode D2;

[0024] The drain of the third MOSFET is connected to the negative terminal of the third diode D3;

[0025] The drain of the fourth MOSFET is connected to the negative terminal of the fourth diode D4;

[0026] The source of the first MOSFET and the drain of the third MOSFET are connected, and the connection point between the source of the first MOSFET and the drain of the third MOSFET is the first output terminal;

[0027] The source of the second MOSFET and the drain of the fourth MOSFET are connected, and the connection point between the source of the second MOSFET and the drain of the fourth MOSFET is the second output terminal.

[0028] An improvement to the energy transfer method of the wireless energy transfer system described above is that the method includes:

[0029] The n-level relay units arranged on the same horizontal line transmit the energy of the energy source to the nth-level relay unit in the n-level relay units arranged on the same horizontal line through resonance.

[0030] Compared with the closest existing technology, the present invention has the following advantages:

[0031] This invention provides a wireless power transmission system, comprising: an energy source and n-level relay units arranged on the same horizontal line; since the transmitting circuit and the receiving circuit of the wireless power transmission system do not have direct physical contact, this solution can meet the requirements of high insulation and ensure the safety of power supply.

[0032] The relay unit provided by this invention consists of a first energy closed-loop circuit, a ferrite core, and a second energy closed-loop circuit. The first energy closed-loop circuit is not connected to a load and is only responsible for transmitting energy to the next coil. This structure allows for a constant current amplitude in the second energy closed-loop circuit, independent of the resistance value, ensuring that the load power can be flexibly and independently adjusted without mutual interference. Each energy closed-loop circuit uses capacitors for series compensation to form a resonant circuit, which can improve the power transmission efficiency of the system. The insertion of ferrite cores in the first and second energy closed-loop circuits can effectively suppress magnetic field leakage and improve the coupling coefficient between coils. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of a wireless power transmission system provided by the present invention;

[0034] Figure 2 This is a schematic diagram of the relay unit structure provided in an embodiment of the present invention;

[0035] Figure 3 This is a schematic diagram of energy flow in the wireless energy transmission system provided in an embodiment of the present invention;

[0036] Figure 4 This refers to the load power when the eight relay units provided in this embodiment of the invention are connected to equal load resistors;

[0037] Figure 5 This refers to the load current amplitude when the eight relay units provided in this embodiment of the invention are connected to unequal load resistors. Detailed Implementation

[0038] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0039] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] This invention provides a wireless power transfer system, comprising:

[0041] Energy source and n-level relay units arranged on the same horizontal line;

[0042] The first-level relay unit in the n-level relay unit is connected to the output end of the energy source;

[0043] The first-level relay unit in the n-level relay unit is used to receive the energy sent by the energy source and transmit the energy to the next-level relay unit;

[0044] In the n-level relay unit, each level of relay unit performs non-contact energy transfer through resonance.

[0045] Where n is a positive integer greater than 2.

[0046] For example, such as Figure 1 As shown, the energy source is the DC bus voltage V. dc It consists of an H-bridge inverter connected to the DC bus voltage. Coil 11 is the initial transmitting coil, connected to the H-bridge inverter, which obtains energy from the inverter and transfers it to subsequent coils. Coil 2 is the last coil, obtaining energy from the previous coil. (The text then repeats the structure of coils 11 and 2.) _ The remaining coils between n2 and n3 not only receive energy from the previous stage as receiving coils but also transmit energy to the next stage coils as transmitting coils. Therefore, energy is transferred stage by stage. Furthermore, the load is only connected to even-numbered coils and draws energy from these coils, such as coil _12 and coil _2_. _ Coils 22, 21, 31, etc., are not connected to any load; while odd-numbered coils are not connected to any load. This topology ensures that the current flowing through the even-numbered coils is constant and independent of the load. Therefore, a change in one load will not affect the power obtained by other loads, meaning that the power of each load can be flexibly and independently adjusted.

[0047] In one embodiment of the present invention, the distance between each relay unit in the n-level relay unit can be equal.

[0048] Furthermore, the relay unit includes: a first energy closed-loop circuit, a ferrite, and a second energy closed-loop circuit arranged sequentially on the same horizontal line.

[0049] The first energy closed-loop circuit consists of a first relay coil and a capacitor connected to the first relay coil;

[0050] The second energy closed-loop circuit consists of a second relay coil, a capacitor, and a load connected in sequence;

[0051] For example, such as Figure 2 As shown, in this invention, ferrite is placed between the first and second energy closed-loop circuits arranged sequentially on the same horizontal line. The coil adopts a bipolar structure because this structure is more robust to coil position displacement. Due to the magnetic isolation effect of the ferrite, the coupling coefficient between coil_11 and coil_12 is reduced, while the coupling coefficient between coil_12 and coil_12 is reduced. _ 21. Because it is placed between two ferrites, the coupling coefficient between them will be enhanced. Therefore, the ferrite provided by the present invention is a ferrite with adjustable shape and size. By adjusting the shape and size of the ferrite, the same coupling coefficient can be obtained between two adjacent coils. At the same time, the coupling coefficient between non-adjacent coils will be further weakened due to the magnetic shielding effect of the ferrite.

[0052] In the embodiments provided by the present invention, the second energy closed loop of each relay unit can provide energy to the secondary circuit load in the high-voltage high-power power electronic equipment in the flexible AC transmission system. Therefore, the load in the present invention may include the drive circuit, sub-unit control circuit, etc. inside the power electronic device.

[0053] like Figure 3 As shown, the first relay coil is used to transfer the received energy to the second relay coil through resonance; the second relay coil is used to provide energy to the secondary circuit of the power electronic equipment in the flexible AC system and transfer the remaining energy to the first relay coil of the next-level relay unit through resonance.

[0054] For example, the ferrite is placed between the first energy closed loop and the second energy closed loop.

[0055] The first relay coil and the second relay coil adopt a bipolar coil structure because this structure is more robust to coil position deviation.

[0056] The energy source is supplied by the DC bus voltage V. dc It consists of an H-bridge inverter connected to the DC bus voltage.

[0057] The H-bridge inverter includes:

[0058] First MOSFET_S1, First diode D1, Second MOSFET_S2, Second diode D2, Third MOSFET_S3, Third diode D3, Fourth MOSFET_S4, Fourth diode D4;

[0059] The drain of the first MOSFET is connected to the cathode of the first diode D1;

[0060] The drain of the second MOSFET is connected to the cathode of the second diode D2;

[0061] The drain of the third MOSFET is connected to the negative terminal of the third diode D3;

[0062] The drain of the fourth MOSFET is connected to the negative terminal of the fourth diode D4;

[0063] The source of the first MOSFET and the drain of the third MOSFET are connected, and the connection point between the source of the first MOSFET and the drain of the third MOSFET is the first output terminal;

[0064] The source of the second MOSFET and the drain of the fourth MOSFET are connected, and the connection point between the source of the second MOSFET and the drain of the fourth MOSFET is the second output terminal.

[0065] For example, DC bus voltage V dc The high-frequency alternating voltage generated by the H-bridge inverter is connected to coil _11 and then the energy is transferred to the subsequent coils. Therefore, the energy is transferred in a step-by-step manner. When the mutual inductance of adjacent coils is equal, the current flowing through all even-numbered coils, such as coil _12, coil _22... coil _n2, has the same current amplitude.

[0066] Based on the same concept as the above system, the present invention also provides an energy transfer method, the method comprising:

[0067] The n-level relay units arranged on the same horizontal line transmit the energy of the energy source to the nth-level relay unit in the n-level relay units arranged on the same horizontal line through resonance.

[0068] To verify the effectiveness of the wireless power transmission system of this invention, a simulation model containing eight relay units was established, and a resistor was used as the load for verification. Figure 4 The load power is given when eight relay units are connected to equal load resistances. According to this, the load current amplitudes are equal, therefore the power of the eight loads should also be equal. Figure 4The simulation results verified this conclusion, showing that each load could obtain a power of 300W. Figure 5 The load current in even-numbered coils is given when the load resistances are different. It can be seen that although the load resistances are not equal, the magnitude of the load current remains the same.

[0069] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0070] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0071] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0072] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0073] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A wireless energy transfer system, characterized in that, The system comprises an energy source and n-stage relay units arranged on the same horizontal line; a first-stage relay unit in the n-stage relay units is connected with an output end of the energy source; the first-stage relay unit in the n-stage relay units is configured to receive energy transmitted by the energy source and transmit the energy to a next-stage relay unit; energy is transmitted between each of the relay units in the n-stage relay units in a resonant manner; n is a positive integer greater than 2; the relay unit comprises a first energy closed loop, a ferrite and a second energy closed loop arranged on the same horizontal line in sequence; the first energy closed loop comprises a first relay coil and a capacitor connected with the first relay coil; the second energy closed loop comprises a second relay coil, a capacitor and a load connected in sequence; the first relay coil is configured to transmit the received energy to the second relay coil in a resonant manner; the second relay coil is configured to provide energy for the load and transmit residual energy to a first relay coil of a next-stage relay unit in a resonant manner, and the load is connected only to the second relay coil; the first relay coil and the second relay coil adopt a bipolar coil structure.

2. The system of claim 1, wherein, The distance between each of the relay units in the n-stage relay units is equal.

3. The system of claim 1, wherein, The ferrite is arranged between the first energy closed loop and the second energy closed loop.

4. The system of claim 1, wherein, The energy source comprises a DC bus voltage and an H-bridge inverter connected with the DC bus voltage.

5. The system of claim 4, wherein, The H-bridge inverter comprises: a first MOSFET, a first diode D1, a second MOSFET, a second diode D2, a third MOSFET, a third diode D3, a fourth MOSFET and a fourth diode D4; the drain of the first MOSFET is connected with the negative electrode of the first diode D1; the drain of the second MOSFET is connected with the negative electrode of the second diode D2; the drain of the third MOSFET is connected with the negative electrode of the third diode D3; the drain of the fourth MOSFET is connected with the negative electrode of the fourth diode D4; the source of the first MOSFET and the drain of the third MOSFET are connected, and the connection point of the source of the first MOSFET and the drain of the third MOSFET is a first output end; the source of the second MOSFET and the drain of the fourth MOSFET are connected, and the connection point of the source of the second MOSFET and the drain of the fourth MOSFET is a second output end.

6. A method of energy transfer for a wireless energy transfer system as defined in any of claims 1-5, characterized in that, The method comprises: n-stage relay units arranged on the same horizontal line transmit energy of an energy source to an nth-stage relay unit in the n-stage relay units in a resonant manner.

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