A wireless power transfer system

Abstract

A wireless power transmission system, the system comprises a direct current power supply, a control circuit, a drive circuit, an inverter circuit, a resonance network, a rectifier circuit and a load; the control circuit is used for providing a pulse width modulation PWM signal; the drive circuit is used for converting the PWM signal into a drive signal for controlling the on-off of the inverter circuit; the inverter circuit is used for inverting the direct current provided by the direct current power supply into a first high-frequency alternating current according to the drive signal; the resonance network comprises two groups of double-sided LCCL in parallel, the primary end of each group of double-sided LCCL is used for converting the first high-frequency alternating current into an alternating magnetic field, and the secondary end of each group of double-sided LCCL is used for converting the alternating magnetic field into a second high-frequency alternating current; the rectifier circuit is used for converting the second high-frequency alternating current into direct current for charging the load.

Description

Technical Field

[0001] This application relates to the field of wireless power transmission, and more particularly to a wireless power transmission system. Background Technology

[0002] With the development of wireless power transfer technology, it has been widely applied in various fields due to its advantages such as convenience, safety, and natural electrical isolation. For example, it can be applied to wireless charging of electric vehicles and drones, and power transmission of underwater machinery and equipment.

[0003] Existing wireless power transmission systems typically employ single-channel electromagnetic resonant networks, resulting in relatively low system operating frequencies. This leads to the following main drawbacks: (1) The resonant circuit is bulky. (2) Output power is limited by the operating frequency and resonant circuit parameters. (3) The overall power density of the system is low. Summary of the Invention

[0004] This application provides a wireless power transmission system with a higher operating frequency and greater power density.

[0005] In a first aspect, this application provides a wireless power transmission system, including a DC power supply, a control circuit, a drive circuit, an inverter circuit, a resonant network, a rectifier circuit, and a load;

[0006] The control circuit is used to provide a pulse width modulation (PWM) signal;

[0007] The driving circuit is used to convert the PWM signal into a driving signal that controls the on / off state of the inverter circuit;

[0008] The inverter circuit is used to invert the DC power supplied by the DC power source into a first high-frequency AC power according to the drive signal.

[0009] The resonant network includes two sets of parallel double-sided inductor-capacitor-capacitor-inductor LCCLs. The primary terminal of each double-sided LCCL is used to convert the first high-frequency alternating current into an alternating magnetic field, and the secondary terminal of each double-sided LCCL is used to convert the alternating magnetic field into a second high-frequency alternating current.

[0010] The rectifier circuit is used to convert the second high-frequency AC power into DC power for charging the load.

[0011] In the above technical solution, the resonant network adopts two sets of parallel double-sided LCCL topologies, which can realize the parallel transmission of electrical energy, effectively improving the power transmission capacity of the wireless power transmission system and the overall power density of the system.

[0012] In one or more embodiments, the primary terminal of each pair of bilateral LCCLs includes a first inductor, a first capacitor, a second capacitor, and a transmitting coil; the first output terminal of the inverter circuit is connected to the input terminal of the first inductor, the output terminal of the first inductor is connected to the input terminals of the first capacitor and the second capacitor, the output terminal of the first capacitor is connected to the input terminal of the transmitting coil, the output terminal of the transmitting coil is connected to the output terminal of the second capacitor, and the output terminal of the second capacitor is connected to the second output terminal of the inverter circuit; the secondary terminal of each pair of bilateral LCCLs includes a second inductor, a third capacitor, a fourth capacitor, and a receiving coil; the output terminal of the receiving coil is connected to the input terminal of the third capacitor, the output terminal of the third capacitor is connected to the input terminal of the fourth capacitor and the input terminal of the second inductor, the output terminal of the second inductor is connected to the first input terminal of the rectifier circuit, the output terminal of the fourth capacitor is connected to the input terminal of the receiving coil, and the input terminal of the receiving coil is connected to the second input terminal of the rectifier circuit.

[0013] In the above technical solution, the two sets of bilateral LCCL structures are symmetrical and connected in parallel, which can realize the parallel transmission of electrical energy, effectively improving the power transmission capacity of the wireless power transmission system and the overall power density of the system.

[0014] In one or more embodiments, the first transmitting coil of the first bilateral LCCL in the two sets of bilateral LCCLs is a Q-type transmitting coil, and the corresponding first receiving coil is a Q-type receiving coil;

[0015] The second transmitting coil of the second bilateral LCCL in the two sets of bilateral LCCLs is a DD type transmitting coil, and the corresponding second receiving coil is a DD type receiving coil.

[0016] In the above technical solution, the resonant network adopts a DDQ type coil. Since the mutual inductance between the DD type coil and the Q type coil is small and negligible, the influence of energy coupling between the two coils on power transmission is solved, thereby enabling parallel power transmission and effectively improving the power transmission capacity of the wireless power transmission system and the overall power density of the system.

[0017] In one or more embodiments, the transmitting coil and the receiving coil are arranged facing each other; the Q-type transmitting coil and the DD-type transmitting coil are stacked; the Q-type receiving coil and the DD-type receiving coil are stacked.

[0018] In the above technical solution, the mutual inductance between the DD-type transmitting coil and the Q-type transmitting coil, and between the DD-type receiving coil and the Q-type receiving coil, is small and negligible. Therefore, stacking the DD-type transmitting coil and the Q-type transmitting coil, and stacking the DD-type receiving coil and the Q-type receiving coil, can solve the influence of energy coupling between the two coils on power transmission, thereby enabling parallel power transmission. Furthermore, when the transmitting coil and the receiving coil are positioned opposite each other, the mutual inductance between the transmitting coil and the receiving coil is the largest and the coupling is the strongest, effectively improving the power transmission capacity of the wireless power transmission system and the overall power density of the system.

[0019] In one or more embodiments, the inverter circuit includes four silicon carbide field-effect transistors (SiC-MOSFETs), the gate of each SiC-MOSFET being connected to the driving circuit; the drain of the first SiC-MOSFET is connected to the drain of the second SiC-MOSFET, the source of the first SiC-MOSFET is connected to the drain of the third SiC-MOSFET, the source of the third SiC-MOSFET is connected to the source of the fourth SiC-MOSFET, and the drain of the fourth SiC-MOSFET is connected to the source of the second SiC-MOSFET.

[0020] In the above technical solution, since SiC-MOSFETs, as high-frequency devices, can withstand higher operating frequencies, the inverter circuit adopts a SiC full-bridge inverter circuit. On the one hand, this can increase the system operating frequency and ensure the stability of the system when operating at high frequencies; on the other hand, since the operating frequency is higher, the parameter values ​​of capacitors and inductors in the resonant network can be reduced, thereby reducing the physical size of the resonant network.

[0021] In one or more embodiments, the driving circuit includes a tri-state gate, an optocoupler, a silicon carbide (SiC) driver chip, and an isolation power supply; the output terminal of the control circuit is connected to the input terminal of the tri-state gate, the output terminal of the tri-state gate is connected to the input terminal of the optocoupler, the output terminal of the optocoupler is connected to the input terminal of the SiC driver chip, and the output terminal of the SiC driver chip is connected to the gate of the SiC-MOSFET; the isolation power supply is used to power the optocoupler and the SiC driver chip.

[0022] In the above technical solution, the PWM signal output by the control circuit is connected to a tri-state gate to improve the driving capability of the signal. The driving signal output by the tri-state gate is connected to an optocoupler to achieve electrical isolation between strong and weak electrical signals. The optocoupler is then connected to the SiC driver chip to convert the PWM signal into a high-level 20V and a low-level -5V driving signal, which is finally connected to the gate of the SiC-MOSFET to realize the turn-on and turn-off operations.

[0023] In one or more embodiments, the wireless power transfer system further includes a power supply voltage and current sampling circuit and / or a load voltage and current sampling circuit; the power supply voltage and current sampling circuit is used to acquire the output voltage and output current of the DC power supply; the load voltage and current sampling circuit is used to acquire the input voltage and input current of the load; the control circuit is further used to calculate the input power of the wireless power transfer system based on the output voltage and output current of the DC power supply; calculate the output power of the wireless power transfer system based on the input voltage and input current of the load; if the input power and / or the output power exceeds a set threshold, the control circuit connected to the DC power supply is disconnected, causing the DC power supply to stop supplying power.

[0024] In the above technical solution, by setting a protection circuit, the DC power supply is stopped when the input power and / or output power exceed a set threshold, thus avoiding excessive input power and / or output power and ensuring the stability of the wireless power transmission system.

[0025] In one or more embodiments, the control circuit is further configured to transmit the operating parameters of the wireless power transmission system to a host computer and a display screen; the operating parameters may be one or more of the following parameters: voltage, current, power and efficiency.

[0026] In the above technical solution, the communication between the control circuit and the host computer allows the host computer to obtain various working indicators of the wireless power transmission system; the communication between the control circuit and the display screen allows the current working status of the wireless power transmission system to be displayed in real time.

[0027] Secondly, embodiments of this application also provide a power supply device, which includes a DC power supply, a control circuit, a drive circuit, an inverter circuit, and an output terminal in a resonant network;

[0028] The control circuit is used to provide a pulse width modulation (PWM) signal;

[0029] The driving circuit is used to convert the PWM signal into a driving signal that controls the on / off state of the inverter circuit;

[0030] The inverter circuit is used to invert the DC power supplied by the DC power source into a first high-frequency AC power according to the drive signal.

[0031] The resonant network includes two sets of parallel-connected bilateral inductor-capacitor-capacitor-inductor LCCLs;

[0032] The output terminal of the resonant network is used to convert the first high-frequency alternating current into an alternating magnetic field through the primary terminals of each pair of bilateral LCCLs.

[0033] Thirdly, embodiments of this application also provide a terminal device, the terminal device including the load of the wireless power transmission system as described in any of the first aspects, the load voltage and current sampling circuit, the rectifier circuit, and the secondary terminals of the two sets of bilateral LCCL resonant networks. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 A schematic diagram of a wireless power transmission system provided in an embodiment of this application;

[0036] Figure 2 A schematic diagram of a resonant network provided in an embodiment of this application;

[0037] Figure 3 This is a schematic diagram of the structure of a DDQ type coil provided in an embodiment of this application;

[0038] Figure 4 A schematic diagram of another DDQ type coil provided in the embodiments of this application;

[0039] Figure 5 A schematic diagram of a drive circuit provided in an embodiment of this application;

[0040] Figure 6 A schematic diagram of another wireless power transmission system provided in this application embodiment;

[0041] Figure 7 A schematic flowchart of a circuit protection control provided in an embodiment of this application;

[0042] Figure 8 A schematic diagram of a voltage and current sampling circuit provided in an embodiment of this application;

[0043] Figure 9 A schematic diagram of another wireless power transmission system provided in this application embodiment;

[0044] Figure 10 A graph of the horizontal offset test provided in the embodiments of this application;

[0045] Figure 11 A graph of the vertical distance test provided in the embodiments of this application;

[0046] Figure 12A graph showing the relationship between system output power, output current, and efficiency and horizontal offset distance provided in an embodiment of this application;

[0047] Figure 13 A diagram showing the relationship between system output power, output current, and efficiency and vertical distance provided in an embodiment of this application;

[0048] Figure 14 The waveforms of the drain-source voltage and drain-source current of the inverter circuit and the voltage and current at the diodes of the rectifier circuit are provided for embodiments of this application. Detailed Implementation

[0049] To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0050] In the embodiments of this application, "multiple" refers to two or more. Terms such as "first" and "second" are used only for descriptive purposes and should not be construed as indicating or implying relative importance or order.

[0051] Figure 1 This is a schematic diagram of the structure of a wireless power transmission system provided in an embodiment of this application, as shown below. Figure 1 As shown, the wireless power transmission system includes a DC power supply 110, a control circuit 120, a drive circuit 130, an inverter circuit 140, a resonant network 150, a rectifier circuit 160, and a load 170.

[0052] The control circuit 120 is used to provide a pulse width modulation (PWM) signal.

[0053] The drive circuit 130 is used to convert the PWM signal into a drive signal that controls the on / off state of the inverter circuit.

[0054] The inverter circuit 140 is used to invert the DC power supplied by the DC power supply 110 into a first high-frequency AC power according to the drive signal.

[0055] The resonant network 150 includes two sets of parallel double-sided inductor-capacitor-capacitor-inductor LCCLs. The primary terminal of each double-sided LCCL is used to convert a first high-frequency alternating current into an alternating magnetic field, and the secondary terminal of each double-sided LCCL is used to convert the alternating magnetic field into a second high-frequency alternating current.

[0056] The rectifier circuit 160 is used to convert the second high-frequency AC power into DC power to charge the load 170.

[0057] In the above technical solution, the resonant network adopts two sets of parallel double-sided LCCL topologies, which can realize the parallel transmission of electrical energy, effectively improving the power transmission capacity of the wireless power transmission system and the overall power density of the system.

[0058] In one or more embodiments, the resonant network is topologically symmetrical with two sets of bilateral LCCLs, and also with symmetrical primary and secondary ends. The primary end of each set of bilateral LCCLs includes a first inductor, a first capacitor, a second capacitor, and a transmitting coil; the secondary end of each set of bilateral LCCLs includes a second inductor, a third capacitor, a fourth capacitor, and a receiving coil.

[0059] Figure 2 This is a schematic diagram of the structure of a resonant network provided in an embodiment of this application, as shown below. Figure 2 As shown, the connection relationship of each device in the first group of double-sided LCCLs is as follows: the first output terminal A of the inverter circuit 140 is connected to the input terminal of the first inductor Lf1, the output terminal of the first inductor Lf1 is connected to the input terminal of the first capacitor C1 and the input terminal of the second capacitor Cf2, the output terminal of the first capacitor C1 is connected to the input terminal of the transmitting coil L1, the output terminal of the transmitting coil L1 is connected to the output terminal of the second capacitor Cf2, and the output terminal of the second capacitor Cf2 is connected to the second output terminal B of the inverter circuit 140.

[0060] The output terminal of the receiving coil L2 is connected to the input terminal of the third capacitor C2. The output terminal of the third capacitor C2 is connected to the input terminal of the fourth capacitor Cf2 and the input terminal of the second inductor Lf2. The output terminal of the second inductor Lf2 is connected to the first input terminal a of the rectifier circuit 160. The output terminal of the fourth capacitor Cf2 is connected to the input terminal of the receiving coil L2. The input terminal of the receiving coil L2 is connected to the second input terminal b of the rectifier circuit 160.

[0061] The connection relationships of each device in the second set of bilateral LCCLs are as follows: the first output terminal A of the inverter circuit 140 is connected to the input terminal of the first inductor Lf3, the output terminal of the first inductor Lf3 is connected to the input terminal of the first capacitor C3 and the input terminal of the second capacitor Cf3, the output terminal of the first capacitor C3 is connected to the input terminal of the transmitting coil L3, the output terminal of the transmitting coil L3 is connected to the output terminal of the second capacitor Cf3, and the output terminal of the second capacitor Cf3 is connected to the second output terminal B of the inverter circuit 140.

[0062] The output terminal of the receiving coil L4 is connected to the input terminal of the third capacitor C4. The output terminal of the third capacitor C4 is connected to the input terminal of the fourth capacitor Cf4 and the input terminal of the second inductor Lf4. The output terminal of the second inductor Lf4 is connected to the first input terminal a of the rectifier circuit 160. The output terminal of the fourth capacitor Cf4 is connected to the input terminal of the receiving coil L4. The input terminal of the receiving coil L4 is connected to the second input terminal b of the rectifier circuit 160.

[0063] In one or more embodiments, the resonant network employs a DDQ type coil, wherein the first transmitting coil (L1) of the first double-sided LCCL in the two sets of double-sided LCCLs is a Q type transmitting coil, and the corresponding first receiving coil (L2) is a Q type receiving coil; the second transmitting coil (L3) of the second double-sided LCCL in the two sets of double-sided LCCLs is a DD type transmitting coil, and the corresponding second receiving coil (L3) is a DD type receiving coil.

[0064] Figure 3 This is a schematic diagram of the structure of a DDQ type coil provided in an embodiment of this application, as shown below. Figure 3 As shown, the transmitting coils are arranged in layers from bottom to top as DD-type transmitting coil assembly 340 and Q-type transmitting coil assembly 330; the receiving coils are arranged in layers from bottom to top as Q-type receiving coil assembly 320 and DD-type receiving coil assembly 310.

[0065] Figure 4 A schematic diagram of another DDQ type coil provided in the embodiments of this application is shown below. Figure 4 As shown, the transmitting coils are arranged in layers from bottom to top as a Q-type transmitting coil assembly 330 and a DD-type transmitting coil assembly 340; the receiving coils are arranged in layers from bottom to top as a DD-type receiving coil assembly 310 and a Q-type receiving coil assembly 320.

[0066] The DD-type transmitting coil and DD-type receiving coil are both double rectangular planar helical coils, with the two rectangular coils wound in opposite directions and connected in series; the Q-type transmitting coil and Q-type receiving coil are both square planar helical coils. Furthermore, when the transmitting and receiving coils are positioned directly opposite each other, the mutual inductance between them is maximized, and the coupling is strongest.

[0067] In the above technical solution, the resonant network adopts a DDQ type coil. Since the mutual inductance between the DD type coil and the Q type coil is small and negligible, the influence of energy coupling between the two coils on power transmission is solved, thereby enabling parallel power transmission and effectively improving the power transmission capacity of the wireless power transmission system and the overall power density of the system.

[0068] In one or more embodiments, the inverter circuit 140 connected to the resonant network is a full-bridge inverter circuit, such as... Figure 2 As shown, the inverter circuit 140 includes four silicon carbide field-effect transistors (SiC-MOSFETs), and the gate of each SiC-MOSFET is connected to the drive circuit 130.

[0069] The drain of the first SiC-MOSFET (S1) is connected to the drain of the second SiC-MOSFET (S2), the source of the first SiC-MOSFET (S1) is connected to the drain of the third SiC-MOSFET (S3), the source of the third SiC-MOSFET (S3) is connected to the source of the fourth SiC-MOSFET (S4), and the drain of the fourth SiC-MOSFET (S4) is connected to the source of the second SiC-MOSFET (S2).

[0070] Since SiC-MOSFETs, as high-frequency devices, can withstand higher operating frequencies, the inverter circuit adopts a SiC full-bridge inverter circuit. On the one hand, this can increase the system operating frequency and ensure the stability of the system when operating at high frequencies; on the other hand, the higher operating frequency can reduce the parameter values ​​of capacitors and inductors in the resonant network, thereby reducing the physical size of the resonant network.

[0071] In one or more embodiments, the connection relationship between the gate of each SiC-MOSFET and one driving circuit is as follows: Figure 5 As shown, the driving circuit includes a tri-state gate 510, an optocoupler 520, a silicon carbide (SiC) driver chip 530, and an isolation power supply 540.

[0072] The output of the control circuit is connected to the input of the tri-state gate 510. The output of the tri-state gate 510 is connected to the input of the optocoupler 520. The output of the optocoupler 520 is connected to the input of the SiC driver chip 530. The output of the SiC driver chip 530 is connected to the gate of the SiC-MOSFET. The isolation power supply 540 is used to power the optocoupler 520 and the SiC driver chip 530.

[0073] In the above technical solution, to ensure the stability of the system operating at high frequencies, the SiC driver chip uses a single-transistor drive with negative voltage turn-off method to control the SiC-MOSFET. One PWM signal output from the control circuit 120 is connected to the tri-state gate 510 to improve the signal driving capability. The drive signal output from the tri-state gate 510 is connected to the optocoupler 520 to achieve electrical isolation between strong and weak electrical signals. The optocoupler 520 is then connected to the SiC driver chip 530, which converts the PWM signal into a high-level 20V and a low-level -5V drive signal, which is finally connected to the gate of the SiC-MOSFET to realize the turn-on and turn-off operations.

[0074] In one or more embodiments, such as Figure 6As shown, the wireless power transmission system also includes a power supply voltage and current sampling circuit 180 and / or a load voltage and current sampling circuit 190. The power supply voltage and current sampling circuit 180 is used to acquire the output voltage and output current of the DC power supply 110, and then transmits the acquired output voltage and output current of the DC power supply to the control circuit 120. The load voltage and current sampling circuit 190 is used to acquire the input voltage and input current of the load 170, and then transmits the acquired input voltage and input current of the load to the wireless communication transmitter 191 via the wireless communication receiver 192, and then the wireless communication receiver 192 transmits it to the control circuit 120.

[0075] In one or more embodiments, the control circuit is further configured to calculate the input power of the wireless power transmission system based on the output voltage and output current of the DC power supply, and calculate the output power of the wireless power transmission system based on the input voltage and input current of the load; if the input power and / or output power exceed a set threshold, the control circuit connected to the DC power supply is disconnected to stop the DC power supply from providing power.

[0076] Figure 7 An exemplary schematic diagram of a circuit protection control provided in an embodiment of this application is shown, such as... Figure 7 As shown, the method includes the following steps:

[0077] Step 701: Set the system's maximum operating power.

[0078] Step 702: Drive the inverter circuit to start the system.

[0079] Step 703: Collect the voltage and current of the DC power supply and the load.

[0080] During power transmission, the voltage and current on the DC bus of the transmitting end and the voltage and current of the load at the receiving end can be detected by the control circuit AD unit at set intervals (e.g., every 10ms or 20ms).

[0081] Step 704: Calculate the system's input power and output power.

[0082] Step 705: Determine whether the input power and / or output power exceed the upper limit power.

[0083] If yes, proceed to step 706; otherwise, proceed to step 707.

[0084] Step 706: The protection circuit is activated.

[0085] If the power limit is exceeded, the control circuit will shut down the relay in the protection circuit and stop driving the inverter circuit, thus ending the wireless transmission of electrical energy.

[0086] Step 707: Protection circuit in standby mode.

[0087] If the power limit is not exceeded, the protection circuit is in standby mode and repeatedly collects voltage and current data and determines whether the power limit is exceeded at set intervals (e.g., every 10ms or 20ms).

[0088] In the above technical solution, by setting a protection circuit, the DC power supply is stopped when the input power and / or output power exceed a set threshold, thus avoiding excessive input power and / or output power and ensuring the stability of the wireless power transmission system.

[0089] Figure 8 This is a schematic diagram of a voltage and current sampling circuit provided in an embodiment of this application. Taking a DC power supply and a voltage acquisition circuit 180 as an example, a current sensor 181 is connected in series with the DC power supply 110, and a voltage sensor 182 is connected in parallel with the DC power supply 110. The output signals of the current sensor 181 and the voltage sensor 182 are connected to the input terminal of a follower 183, which is used to reduce the impedance in the line. The output terminal of the follower 183 is connected to the input terminal of a proportional-integral amplifier 184, which is used to modulate and amplify the weak electrical signal to between 0 and 3V. The output terminal of the proportional-integral amplifier 184 is connected to the control circuit 120 through a clamping diode 185 for AD acquisition to obtain the voltage and current values ​​of the DC power supply 110.

[0090] In one or more embodiments, such as Figure 9 As shown, the wireless power transfer system also includes a host computer 910 and a display screen 920. The control circuit 120 is also used to transmit the operating parameters of the wireless power transfer system to the host computer 910 and the display screen 920, wherein the operating parameters can be one or more of the following parameters: voltage, current, power and efficiency.

[0091] For example, the control circuit 120 can communicate with the host computer 910 through a universal asynchronous receiver / transmitter (UART) to transmit in real time the current output voltage and output current of the DC power supply of the wireless power transmission system, the input voltage and input current of the load, or the input power, output power, transmission efficiency, etc. of the system, so that the host computer can know the various working indicators of the wireless power transmission system when it is working.

[0092] The control circuit 120 can communicate with the display screen 920 via the inter-integrated circuit (IIC) bus to transmit in real time the current output voltage and current of the DC power supply of the wireless power transmission system, the input voltage and current of the load, or the input power, output power, transmission efficiency of the system, etc. The display screen can display the current working status of the wireless power transmission system in real time.

[0093] This application provides a wireless power transfer system. The resonant network adopts a parallel two-sided LCCL topology and uses DDQ type coils. Since the mutual inductance between the DD and Q type coils is small and negligible, the influence of energy coupling between the two coils on power transfer is solved, thereby enabling parallel power transfer and effectively improving the power transfer capability and overall power density of the wireless power transfer system. The inverter circuit adopts a SiC full-bridge inverter circuit, which can increase the system operating frequency and ensure the stability of the system at high frequencies. Furthermore, the higher operating frequency allows for a reduction in the values ​​of capacitors and inductors in the resonant network, thus reducing the physical size of the resonant network.

[0094] The following examples, using relevant parameters and test data of a prototype wireless power transmission system, illustrate the technical effects that the technical solution of this application can achieve.

[0095] Both the Q-type transmitting and receiving coils are made of Mylar wire with an outer diameter of 1.98mm, wound into 28-turn square planar spiral coils, with dimensions of 250mm × 250mm and an inductance of 82.35μH. Both the DD-type transmitting and receiving coils are made of Mylar wire with an outer diameter of 1.98mm, wound into 16-turn double rectangular planar spiral coils. The two rectangular coils are wound in opposite directions and connected in series. The dimensions of a single rectangular coil are 250mm × 110mm, and the inductance is 73.79μH.

[0096] Based on the topology of the resonant network, the parameters of each reactive component can be determined as follows: the inductance values ​​of compensation inductors Lf1 and Lf2 are 6.49 μH, the inductance values ​​of inductors Lf3 and Lf4 are 8.39 μH, the capacitance values ​​of compensation capacitors C1 and C2 are 4.2 nF, the capacitance values ​​of compensation capacitors C3 and C4 are 3.8 nF, the capacitance values ​​of compensation capacitors Cf1 and Cf2 are 43.3 nF, and the capacitance values ​​of compensation capacitors Cf3 and Cf4 are 33.5 nF.

[0097] In the inverter circuit, the SiC-MOSFET is model UJ3C065080K3S with a working frequency of 300kHz. The optocoupler is a TLP117 type optocoupler, and the SiC driver chip is an IXDI614YI type SiC driver chip. The voltage sensor and current sensor in the voltage and current sampling circuit are LV25-P and LA55-P Hall sensors, respectively.

[0098] The DC power supply has an input voltage Ui of 48V, a rated output power Pout of 800W, and an operating frequency f of 300kHz. The mutual inductance M between the coils is determined by measuring the series inductance Ld (for DD type) and series inductance Lr (for Q type) transmitter and receiver coils, respectively, using the following formula:

[0099]

[0100] Figure 10 This is a graph showing the change in mutual inductance between the DDQ coils as a function of lateral offset during a horizontal offset test. The vertical distance Δh between the transmitting and receiving coils is maintained at 8 cm, while the horizontal offset distance Δl between the transmitting and receiving coils varies from 0 to 14 cm. Figure 10 As shown, with the increase of horizontal offset distance, the mutual inductance between the DD-type transmitting and receiving coils and the mutual inductance between the Q-type transmitting and receiving coils gradually decrease.

[0101] Figure 11 This is a graph showing the mutual inductance between the DDQ coils as a function of vertical distance during a vertical distance test. The horizontal offset distance Δl between the transmitting and receiving coils is maintained at 0 cm. The vertical distance Δh between the transmitting and receiving coils varies from 6 to 18 cm. Figure 11 As shown, the mutual inductance between the DD-type transmitting and receiving coils and the mutual inductance between the Q-type transmitting and receiving coils gradually decrease with increasing vertical distance.

[0102] according to Figure 10 and Figure 11 It can be seen that when the vertical distance between the transmitting and receiving coils Δh = 6cm and the offset distance Δl = 0cm, the mutual inductance between the transmitting and receiving coils is at its maximum, and the coupling is at its strongest. Among these, the coupling coefficient k of the Q-type coil... Q The coupling coefficient k of the DD-type coil is 0.346. DD The value is 0.222. As the horizontal offset distance increases, the coupling between coils gradually weakens, but the attenuation coefficient of the DD type coil is smaller than that of the Q type coil, which can improve the anti-offset capability of the entire system.

[0103] Figure 12 The graph shows the relationship between the system output power, output current, and efficiency and the horizontal offset distance Δl. Figure 13 The graph shows the relationship between the system output power, output current, and efficiency and the vertical distance Δh.

[0104] according to Figure 12 and Figure 13 It can be seen that, without changing any other system conditions, by only changing the horizontal offset distance Δl and the vertical distance Δh between the transmitting and receiving coils, the maximum system output power Pout can be 1510W, the maximum output current Io can be 17.4A, and the efficiency can be maintained between 82.9% and 94.4%. This demonstrates that the wireless power transmission system of this application has high-power and high-efficiency transmission characteristics. The prototype system volume is approximately 0.002m³, and the overall system power density is 671.63kW / m³, compared to the power density of only 350.71kW / m³ for a single-channel LCCL topology with the same parameters, indicating that the wireless power transmission system of this application has high power density transmission characteristics.

[0105] Figure 14 The waveforms show the drain-source voltage and drain-source current of the SiC inverter circuit, and the voltage and current at the diodes in the rectifier circuit. Figure 14 As shown, the drain-source voltage Vds and drain-source current Ids at the SiC-MOSFET remain in phase, while the voltage Vr and current Io at the rectifier diode remain in phase and lag the waveform at the SiC-MOSFET by 270°. During the voltage turn-on and turn-off processes at both locations, the current is 0A. At this time, the system is in a soft-switching (zero-volume switch, ZVS) state, which can effectively reduce switching losses and ensure high-efficiency transmission of the system.

[0106] It should be noted that the models and parameters of the above-mentioned devices are only examples to illustrate the technical effects that this application can achieve, and the embodiments of this application do not specifically limit the models and parameters of the devices.

[0107] Based on the same technical concept, embodiments of this application provide a power supply device, which includes a DC power supply, a control circuit, a drive circuit, an inverter circuit, and an output terminal in a resonant network.

[0108] The control circuit is used to provide pulse width modulation (PWM) signals.

[0109] The drive circuit is used to convert the PWM signal into a drive signal that controls the on / off state of the inverter circuit.

[0110] The inverter circuit is used to invert the DC power supplied by the DC power source into a first high-frequency AC power according to the drive signal.

[0111] The resonant network consists of two sets of parallel bilateral inductor-capacitor-capacitor-inductor LCCLs.

[0112] The output terminal in the resonant network is used to convert the first high-frequency alternating current into an alternating magnetic field through the primary terminals of each pair of bilateral LCCLs.

[0113] Based on the same technical concept, embodiments of this application provide a terminal device, which includes a wireless power transmission system load as described above, a load voltage and current sampling circuit, a rectifier circuit, and the secondary terminals of two sets of bilateral LCCL resonant networks.

[0114] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0115] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A wireless power transmission system, characterized in that, It includes a DC power supply, control circuit, drive circuit, inverter circuit, resonant network, rectifier circuit, and load; The control circuit is used to provide a pulse width modulation (PWM) signal; The driving circuit is used to convert the PWM signal into a driving signal that controls the on / off state of the inverter circuit; The inverter circuit is used to invert the DC power supplied by the DC power source into a first high-frequency AC power according to the drive signal. The resonant network includes two sets of parallel double-sided inductor-capacitor-capacitor-inductor LCCLs. The primary terminal of each double-sided LCCL is used to convert the first high-frequency alternating current into an alternating magnetic field, and the secondary terminal of each double-sided LCCL is used to convert the alternating magnetic field into a second high-frequency alternating current. The first transmitting coil of the first double-sided LCCL is a Q-type transmitting coil, and the corresponding first receiving coil is a Q-type receiving coil. The second transmitting coil of the second double-sided LCCL is a DD-type transmitting coil, and the corresponding second receiving coil is a DD-type receiving coil. The DD-type coil and the Q-type coil in the double-sided LCCL transmit current of the same frequency. The rectifier circuit is used to convert the second high-frequency AC power into DC power for charging the load.

2. The wireless power transmission system according to claim 1, characterized in that, The primary end of each pair of double-sided LCCLs includes a first inductor, a first capacitor, a second capacitor, and a transmitting coil; The first output terminal of the inverter circuit is connected to the input terminal of the first inductor, the output terminal of the first inductor is connected to the input terminal of the first capacitor and the input terminal of the second capacitor, the output terminal of the first capacitor is connected to the input terminal of the transmitting coil, the output terminal of the transmitting coil is connected to the output terminal of the second capacitor, and the output terminal of the second capacitor is connected to the second output terminal of the inverter circuit. The secondary terminals of each pair of bilateral LCCLs include a second inductor, a third capacitor, a fourth capacitor, and a receiving coil; The output terminal of the receiving coil is connected to the input terminal of the third capacitor. The output terminal of the third capacitor is connected to the input terminal of the fourth capacitor and the input terminal of the second inductor. The output terminal of the second inductor is connected to the first input terminal of the rectifier circuit. The output terminal of the fourth capacitor is connected to the input terminal of the receiving coil. The input terminal of the receiving coil is connected to the second input terminal of the rectifier circuit.

3. The wireless power transmission system according to claim 1, characterized in that, The transmitting coil and the receiving coil are positioned opposite each other; The Q-type transmitting coil and the DD-type transmitting coil are stacked together; the Q-type receiving coil and the DD-type receiving coil are stacked together.

4. The wireless power transmission system according to claim 1, characterized in that, The inverter circuit includes four silicon carbide field-effect transistors (SiC-MOSFETs), and the gate of each SiC-MOSFET is connected to the driving circuit. The drain of the first SiC-MOSFET is connected to the drain of the second SiC-MOSFET, the source of the first SiC-MOSFET is connected to the drain of the third SiC-MOSFET, the source of the third SiC-MOSFET is connected to the source of the fourth SiC-MOSFET, and the drain of the fourth SiC-MOSFET is connected to the source of the second SiC-MOSFET.

5. The wireless power transmission system according to claim 4, characterized in that, The driving circuit includes a tri-state gate, an optocoupler, a silicon carbide (SiC) driver chip, and an isolation power supply. The output terminal of the control circuit is connected to the input terminal of the tri-state gate, the output terminal of the tri-state gate is connected to the input terminal of the optocoupler, the output terminal of the optocoupler is connected to the input terminal of the SiC driver chip, and the output terminal of the SiC driver chip is connected to the gate of the SiC-MOSFET. The isolated power supply is used to power the optocoupler and the SiC driver chip.

6. The wireless power transmission system according to claim 1, characterized in that, It also includes power supply voltage and current sampling circuits and / or load voltage and current sampling circuits; The power supply voltage and current sampling circuit is used to collect the output voltage and output current of the DC power supply; the load voltage and current sampling circuit is used to collect the input voltage and input current of the load; The control circuit is also used to calculate the input power of the wireless power transmission system based on the output voltage and output current of the DC power supply; and to calculate the output power of the wireless power transmission system based on the input voltage and input current of the load. If the input power and / or the output power exceed a set threshold, the protection circuit connected to the DC power supply is disconnected, causing the DC power supply to stop supplying power.

7. The wireless power transmission system according to claim 6, characterized in that, The control circuit is also used to transmit the operating parameters of the wireless power transmission system to the host computer and the display screen; the operating parameters may be one or more of the following parameters: voltage, current, power and efficiency.

8. A power supply device, characterized in that, The power supply device includes a DC power supply, a control circuit, a drive circuit, an inverter circuit, and an output terminal in a resonant network. The control circuit is used to provide a pulse width modulation (PWM) signal; The driving circuit is used to convert the PWM signal into a driving signal that controls the on / off state of the inverter circuit; The inverter circuit is used to invert the DC power supplied by the DC power source into a first high-frequency AC power according to the drive signal. The resonant network includes two sets of parallel-connected bilateral inductor-capacitor-capacitor-inductor LCCLs; The output terminal of the resonant network is used to convert the first high-frequency alternating current into an alternating magnetic field through the primary terminal of each set of bilateral LCCLs, and to convert the alternating magnetic field into a second high-frequency alternating current through the secondary terminal of each set of bilateral LCCLs; the first transmitting coil of the first set of bilateral LCCLs is a Q-type transmitting coil, and the corresponding first receiving coil is a Q-type receiving coil; the second transmitting coil of the second set of bilateral LCCLs is a DD-type transmitting coil, and the corresponding second receiving coil is a DD-type receiving coil; the DD-type coil and the Q-type coil in the bilateral LCCL transmit current of the same frequency.

9. A terminal device, characterized in that, The terminal device includes the load, the load voltage and current sampling circuit, the rectifier circuit, and the secondary terminal of the resonant network of the wireless power transmission system as described in claim 6 or 7.

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