An underwater single-capacitor wireless power transmission system and automatic tuning method

Abstract

The application provides an underwater single-capacitance wireless power transmission system and an automatic tuning method, and belongs to the field of power transmission.The system comprises a power supply, a load, a primary side full-bridge converter, a secondary side full-bridge converter, an energy transmission electrode plate, a primary side signal sampling module, a secondary side signal sampling module and a DSP controller.The power supply, the primary side full-bridge converter, the energy transmission electrode plate, the secondary side full-bridge converter and the load are sequentially connected to transmit the current at the power supply to the load.The primary side signal sampling module collects the primary side voltage and current, the secondary side signal sampling module collects the secondary side voltage and current, the primary side voltage and current and the secondary side voltage and current are transmitted to the DSP controller through WiFi, the DSP controller calculates the ZVS angle according to the primary side voltage and current, calculates the system efficiency according to the primary side voltage and current and the secondary side voltage and current, and adjusts the working frequency of the primary side full-bridge converter.The application improves the stability and efficiency of underwater power transmission.

Description

Technical Field

[0001] This invention relates to the field of power transmission, and in particular to an underwater single-capacitor wireless power transmission system and automatic tuning method based on WiFi communication. Background Technology

[0002] With the rapid development of ocean exploration and autonomous underwater vehicles (AUVs), underwater wireless power transfer technology has gradually become a research hotspot in the field of wireless charging. In the underwater environment, traditional wired power transfer methods have many limitations, such as difficulties in wiring and susceptibility to damage. Therefore, researchers have begun to explore underwater wireless power transfer technology to solve these problems.

[0003] Underwater single-capacitor wireless power transfer technology is an emerging underwater wireless charging technology that utilizes electric field coupling to transfer electrical energy in an underwater environment. Compared to traditional inductive wireless power transfer, capacitive transfer eliminates eddy current losses, and the relative permittivity of seawater is 81 times that of air. Therefore, capacitive transfer can significantly increase the transmission distance of underwater wireless power. Electrical energy is stored in a capacitor and then transferred to the receiver via an electric field. Single-capacitor wireless power transfer technology uses only one pair of plates (one capacitor) to transfer electrical energy. In effect, this capacitor and the system form a loop with stray capacitance at infinity, thereby enabling the transfer of electrical energy.

[0004] Wireless power transfer with a single capacitor is affected by stray capacitance. When a measuring device is connected to the circuit, it impacts the overall system. Related papers have demonstrated that when measuring the primary voltage with an oscilloscope, the system output current decreases by 10% compared to when the voltage is not measured with an oscilloscope. This is because the parasitic capacitance in the current probe affects the overall system; a portion of the system current flows to ground through this parasitic capacitance instead of being transmitted to the secondary side via the single capacitor coupling. If a traditional wired connection is used to connect the sensor in series with the controller, parameters such as the capacitance in the sensor will cause some power loss, thus reducing the overall system efficiency.

[0005] Therefore, there is an urgent need for a method that can achieve efficient and stable wireless power transmission in different underwater environments. Summary of the Invention

[0006] The purpose of this invention is to provide an underwater single-capacitor wireless power transmission system and an automatic tuning method, which can improve the stability and efficiency of underwater power transmission.

[0007] To achieve the above objectives, the present invention provides the following solution:

[0008] An underwater single-capacitor wireless power transfer system includes: a power supply, a load, a primary-side full-bridge converter, a secondary-side full-bridge converter, an energy transfer plate, a primary-side signal sampling module, a secondary-side signal sampling module, and a DSP controller.

[0009] The power supply, the primary-side full-bridge converter, the energy transmission plate, the secondary-side full-bridge converter, and the load are connected in sequence to transmit the current from the power supply to the load.

[0010] The primary-side signal sampling module is connected to the primary-side full-bridge converter, and the primary-side signal sampling module is used to collect the primary-side voltage and primary-side current.

[0011] The secondary-side signal sampling module is connected to the secondary-side full-bridge converter, and the secondary-side signal sampling module is used to collect the secondary-side voltage and secondary-side current.

[0012] Both the primary-side signal sampling module and the secondary-side signal sampling module transmit the primary-side voltage, the primary-side current, the secondary-side voltage, and the secondary-side current to the DSP controller via WiFi;

[0013] The DSP controller is connected to the primary-side full-bridge converter. The DSP controller is used to calculate the ZVS angle and system efficiency based on the primary-side voltage, the primary-side current, the secondary-side voltage, and the secondary-side current, and to adjust the operating frequency of the primary-side full-bridge converter based on the ZVS angle and the system efficiency.

[0014] Optionally, the energy transmission plate includes a primary energy transmitting plate and a secondary energy receiving plate;

[0015] The primary-side energy transmitting plate is connected to the primary-side full-bridge converter; the secondary-side energy receiving plate is connected to the secondary-side full-bridge converter.

[0016] There is a set distance between the primary energy transmitting electrode and the secondary energy receiving electrode.

[0017] Optionally, both the primary energy transmitting electrode and the secondary energy receiving electrode are made of aluminum.

[0018] Optionally, the power supply is a DC power supply; the primary-side full-bridge converter includes an inverter circuit and a primary-side compensation network;

[0019] The inverter circuit is connected to the DC power supply and the primary-side compensation network respectively. The primary-side compensation network is also connected to the primary-side energy transmitting plate. The primary-side compensation network and the primary-side energy transmitting plate form a primary-side resonant circuit to minimize reactive power in the primary-side circuit.

[0020] The primary-side signal sampling module is located between the inverter circuit and the primary-side compensation network to collect the primary-side voltage and primary-side current.

[0021] The DSP controller is connected to the inverter circuit. The DSP controller generates a PWM signal based on the ZVS angle and the system efficiency to adjust the operating frequency of the inverter circuit.

[0022] Optionally, the primary-side compensation network includes a first inductor and a first capacitor;

[0023] The first output terminal of the inverter circuit is connected to one end of the first inductor, and the second output terminal of the inverter circuit is connected to one end of the first capacitor; the other end of the first inductor is connected to the primary side energy transmitting plate; the other end of the first capacitor is connected between the first inductor and the primary side energy transmitting plate.

[0024] Optionally, the primary-side signal sampling module includes a primary-side voltage divider resistor, a primary-side voltage sensor, a primary-side current sensor, and a primary-side WiFi module; the primary-side WiFi module is in client mode; the WiFi module in the DSP controller is in AP mode.

[0025] One end of the primary-side voltage divider resistor is connected between the first output terminal of the inverter circuit and the first inductor, and the other end of the primary-side voltage divider resistor is connected to the primary-side voltage sensor.

[0026] The primary-side current sensor is connected to the second output terminal of the inverter circuit, the primary-side voltage sensor, and the first capacitor, respectively.

[0027] The primary-side voltage divider resistor is used to divide the voltage output by the inverter circuit; the primary-side voltage sensor is used to collect the primary-side voltage; the primary-side current sensor is used to collect the primary-side current; and the primary-side WiFi module is used to send the primary-side voltage and the primary-side current to the WiFi module in the DSP controller.

[0028] Optionally, the secondary-side full-bridge converter includes a secondary-side compensation network and a rectifier circuit;

[0029] The rectifier circuit is connected to the secondary-side compensation network and the load respectively. The secondary-side compensation network is also connected to the secondary-side energy receiving plate. The secondary-side compensation network and the secondary-side energy receiving plate form a secondary-side resonant circuit, which minimizes the reactive power in the secondary-side circuit.

[0030] The secondary-side signal sampling module is located between the secondary-side compensation network and the rectifier circuit to collect the secondary-side voltage and secondary-side current.

[0031] Optionally, the secondary-side compensation network includes a second inductor and a second capacitor;

[0032] The first input terminal of the rectifier circuit is connected to one end of the second inductor, and the second input terminal of the rectifier circuit is connected to one end of the second capacitor; the other end of the second inductor is connected to the secondary side energy receiving plate; the other end of the second capacitor is connected between the second inductor and the secondary side energy receiving plate.

[0033] Optionally, the secondary-side signal sampling module includes a secondary-side voltage divider resistor, a secondary-side voltage sensor, a secondary-side current sensor, and a secondary-side WiFi module; the secondary-side WiFi module is in client mode; the WiFi module in the DSP controller is in AP mode.

[0034] One end of the secondary-side voltage divider resistor is connected between the first input terminal of the rectifier circuit and the second inductor, and the other end of the secondary-side voltage divider resistor is connected to the secondary-side voltage sensor.

[0035] The secondary current sensor is connected to the second input terminal of the rectifier circuit, the secondary voltage sensor, and the second capacitor, respectively.

[0036] The secondary-side voltage divider resistor is used to divide the voltage input to the rectifier circuit; the secondary-side voltage sensor is used to collect the secondary-side voltage; the secondary-side current sensor is used to collect the secondary-side current; and the secondary-side WiFi module is used to send the secondary-side voltage and the secondary-side current to the WiFi module in the DSP controller.

[0037] Optionally, the DSP controller calculates the ZVS angle based on the primary side voltage and the primary side current, and calculates the system efficiency based on the primary side voltage, the primary side current, the secondary side voltage, and the secondary side current.

[0038] To achieve the above objectives, the present invention also provides the following solution:

[0039] An automatic tuning method for underwater single-capacitor wireless power transfer, applied to the aforementioned underwater single-capacitor wireless power transfer system, the automatic tuning method comprising:

[0040] The DSP controller adjusts the operating frequency of the primary-side full-bridge converter according to a pre-stored built-in frequency list;

[0041] For any operating frequency of the primary-side full-bridge converter, the primary-side voltage and primary-side current are collected by the primary-side signal sampling module and transmitted to the DSP controller via WiFi; the secondary-side voltage and secondary-side current are collected by the secondary-side signal sampling module and transmitted to the DSP controller via WiFi.

[0042] The DSP controller calculates the ZVS angle and system efficiency of the primary-side full-bridge converter at the operating frequency based on the primary-side voltage, the primary-side current, the secondary-side voltage, and the secondary-side current.

[0043] The DSP controller determines the optimal system frequency and the best ZVS angle based on the ZVS angle and system efficiency of the primary-side full-bridge converter at each operating frequency, and controls the primary-side full-bridge converter to transmit power according to the operating frequency corresponding to the optimal system frequency and the best ZVS angle.

[0044] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects: the primary-side signal sampling module and the secondary-side signal sampling module of the present invention transmit the primary-side voltage, primary-side current, secondary-side voltage and secondary-side current to the DSP controller via WiFi. The DSP controller calculates the ZVS angle and system efficiency based on the primary-side voltage, primary-side current, secondary-side voltage and secondary-side current, and adjusts the operating frequency of the primary-side full-bridge converter according to the ZVS angle and system efficiency, so that the system can achieve optimal efficiency and realize efficient and stable wireless power transmission in different underwater environments. Attached Figure Description

[0045] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0046] Figure 1 A schematic diagram of the underwater single-capacitor wireless power transmission system provided by the present invention;

[0047] Figure 2 Topology diagram of the underwater single-capacitor wireless power transfer system provided by the present invention;

[0048] Figure 3 This is a schematic diagram of the signal sampling module;

[0049] Figure 4 This is a schematic diagram illustrating the calculation process of the ZVS angle;

[0050] Figure 5 Equivalent circuit diagram of the underwater single-capacitor wireless power transmission system provided by the present invention;

[0051] Figure 6 A flowchart of the automatic tuning method provided by the present invention;

[0052] Figure 7 This is a schematic diagram of a WiFi network.

[0053] Symbol explanation: 1-Power supply, 2-Inverter circuit, 3-Primary side compensation network, 4-Energy transmission plate, 5-Secondary side compensation network, 6-Rectifier circuit, 7-Load, 8-DSP controller, 9-Host computer. Detailed Implementation

[0054] 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, and 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.

[0055] The purpose of this invention is to provide an underwater single-capacitor wireless power transfer system and an automatic tuning method, which solves the problem that the single-capacitor wireless power transfer method may cause changes in system parameters (self-capacitance and mutual capacitance of the plates, and stray capacitance of other devices) under different environments.

[0056] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0057] like Figure 1 As shown, the underwater single-capacitor wireless power transmission system provided by the present invention includes: a power supply 1, a load 7, a primary-side full-bridge converter, a secondary-side full-bridge converter, an energy transmission plate 4, a primary-side signal sampling module, a secondary-side signal sampling module, and a DSP controller 8.

[0058] The power supply 1, the primary-side full-bridge converter, the energy transmission plate 4, the secondary-side full-bridge converter, and the load 7 are connected in sequence to transmit the current from the power supply 1 to the load 7. The power supply 1 is a DC power supply, typically a battery. The load 7 is the electrical load of the underwater equipment or a battery.

[0059] Specifically, the energy transmission plate 4 includes a primary-side energy transmitting plate and a secondary-side energy receiving plate. The primary-side energy transmitting plate is connected to the primary-side full-bridge converter. The secondary-side energy receiving plate is connected to the secondary-side full-bridge converter. A predetermined distance exists between the primary-side energy transmitting plate and the secondary-side energy receiving plate.

[0060] In this embodiment, both the primary-side energy transmitting plate and the secondary-side energy receiving plate are made of aluminum. Both the primary-side energy transmitting plate and the secondary-side energy receiving plate are rectangular. The two aluminum plates form a coupling capacitor for energy transmission.

[0061] The primary-side full-bridge converter includes an inverter circuit 2 and a primary-side compensation network 3. The inverter circuit 2 is a high-frequency inverter circuit. The inverter circuit 2 is connected to both the DC power supply and the primary-side compensation network 3, which is also connected to the primary-side energy transmitting plate. The primary-side compensation network 3 and the primary-side energy transmitting plate form a primary-side resonant circuit, minimizing reactive power in the primary-side circuit. A primary-side signal sampling module is located between the inverter circuit 2 and the primary-side compensation network 3 to collect primary-side voltage and current.

[0062] Among them, such as Figure 2 As shown, the primary-side compensation network 3 includes a first inductor L1 and a first capacitor C1. The first output terminal of the inverter circuit 2 is connected to one end of the first inductor L1, and the second output terminal of the inverter circuit 2 is connected to one end of the first capacitor C1. The other end of the first inductor L1 is connected to the primary-side energy transmitting plate. The other end of the first capacitor C1 is connected between the first inductor L1 and the primary-side energy transmitting plate.

[0063] The DSP controller 8 is connected to the inverter circuit 2. The DSP controller 8 generates a PWM signal based on the ZVS angle and the system efficiency to adjust the operating frequency of the inverter circuit 2.

[0064] The primary-side signal sampling module is connected to the primary-side full-bridge converter, and is used to acquire the primary-side voltage and current. The primary-side signal sampling module can obtain the phase of the primary-side voltage and current.

[0065] Specifically, such as Figure 3 As shown, the primary-side signal sampling module includes a primary-side voltage divider resistor R. U1 The system includes a primary-side voltage sensor, a primary-side current sensor, and a primary-side WiFi module. The primary-side WiFi module operates in client mode. The WiFi module in the DSP controller 8 operates in access point (AP) mode.

[0066] The primary side voltage divider resistor R U1 One end is connected between the first output terminal of the inverter circuit 2 and the first inductor L1, and the primary side voltage divider resistor R U1 The other end is connected to the primary-side voltage sensor. The primary-side current sensor is connected to the second output terminal of the inverter circuit 2, the primary-side voltage sensor, and the first capacitor C1, respectively. The primary-side voltage divider resistor R U1 The primary side voltage sensor is used to divide the voltage output of the inverter circuit 2. The primary side voltage sensor is used to collect the primary side voltage. The primary side current sensor is used to collect the primary side current. The primary side WiFi module is used to send the primary side voltage and the primary side current to the WiFi module in the DSP controller 8.

[0067] The secondary-side full-bridge converter includes a secondary-side compensation network 5 and a rectifier circuit 6. The rectifier circuit 6 is connected to both the secondary-side compensation network 5 and the load 7. The secondary-side compensation network 5 is also connected to the secondary-side energy receiving plate. A filter capacitor is also provided between the rectifier circuit 6 and the load 7 to handle pulsating DC current. The secondary-side compensation network 5 and the secondary-side energy receiving plate form a secondary-side resonant circuit, minimizing reactive power in the secondary-side circuit. A secondary-side signal sampling module is located between the secondary-side compensation network 5 and the rectifier circuit 6 to collect secondary-side voltage and current.

[0068] The secondary-side compensation network 5 includes a second inductor L2 and a second capacitor C2. The first input terminal of the rectifier circuit 6 is connected to one end of the second inductor L2, and the second input terminal of the rectifier circuit 6 is connected to one end of the second capacitor C2. The other end of the second inductor L2 is connected to the secondary-side energy receiving plate. The other end of the second capacitor C2 is connected between the second inductor L2 and the secondary-side energy receiving plate.

[0069] Figure 2 In the diagram, G1 to G4 are the four switching transistors in inverter circuit 2, and D1 to D4 are the four rectifier diodes in rectifier circuit 6. C inv C is the stray capacitance to ground on the primary side. rec The stray capacitance to ground on the secondary side is a component of the system's virtual loop and can be measured using an LCR meter.

[0070] In this invention, energy flows from the primary side to the secondary side. During this process, the primary-side full-bridge converter operates in inverter mode, converting the DC power from power source 1 into AC power. Simultaneously, the secondary-side full-bridge converter operates in active rectification mode, converting the received AC power into DC power to supply power to load 7. Specifically, the DC power supply is converted into high-frequency AC power by a high-frequency inverter circuit. A high voltage is generated in the primary-side energy transmitting plate through the primary-side resonant circuit. Simultaneously, the secondary-side receiving plate senses the transmitted energy through the secondary-side resonant circuit and also receives high-frequency AC power on the secondary side. This AC power is finally converted back into DC power by the rectifier circuit 6 to provide energy to load 7.

[0071] The secondary-side signal sampling module is connected to the secondary-side full-bridge converter, and the secondary-side signal sampling module is used to collect the secondary-side voltage and secondary-side current.

[0072] Specifically, the secondary-side signal sampling module includes a secondary-side voltage divider resistor R. U2 The system includes a secondary-side voltage sensor, a secondary-side current sensor, and a secondary-side WiFi module. The secondary-side WiFi module operates in client mode. The WiFi module in the DSP controller 8 operates in access point (AP) mode.

[0073] The secondary voltage divider resistor R U2 One end is connected between the first input terminal of the rectifier circuit 6 and the second inductor L2, and the secondary side voltage divider resistor R U2 The other end is connected to the secondary-side voltage sensor. The secondary-side current sensor is connected to the second input terminal of the rectifier circuit 6, the secondary-side voltage sensor, and the second capacitor C2, respectively. The secondary-side voltage divider resistor R U2 The secondary side voltage sensor is used to divide the voltage input to the rectifier circuit 6. The secondary side voltage sensor is used to acquire the secondary side voltage. The secondary side current sensor is used to acquire the secondary side current. The secondary side WiFi module is used to send the secondary side voltage and the secondary side current to the WiFi module in the DSP controller 8.

[0074] Figure 3 In the middle, the primary side voltage divider resistor R U1 and secondary side voltage divider resistor R U2 Used for the conversion of strong and weak current, R f1 R is the precision sampling resistor in the primary voltage sensor. f2 R is the precision sampling resistor in the primary current sensor. f3 R is the precision sampling resistor in the secondary voltage sensor. f4 This is a precision sampling resistor in a secondary current sensor.

[0075] In practical applications, connecting voltage and current sensors to the DSP controller 8 via wiring hinders the expansion of peripheral devices. Therefore, this invention uses WiFi to transmit current and voltage signals. The primary and secondary voltages are first converted into small currents by a voltage divider resistor, then sampled by a current transformer, and finally converted into differential AC voltage signals by a precision sampling resistor. The input voltage value is then obtained by the acquisition circuit. Sampling of the primary and secondary currents is similar to voltage sampling, except that a voltage divider operation is not required; sampling is performed directly through the current transformer. The acquisition circuit includes a controller, a WiFi module, and a filtering circuit, which can obtain stable sampled values, which are then transmitted to the DSP controller 8 via WiFi.

[0076] The principles of current sensors and voltage sensors are similar to those of transformers. N1 and N2 are the number of coil turns at both ends of the current sensor (voltage sensor), and U1, U2, I1, and I2 are the voltage and current on both sides of the current sensor (voltage sensor), respectively.

[0077] The DSP controller 8 is connected to the primary-side full-bridge converter. The DSP controller 8 is used to calculate the ZVS angle and system efficiency based on the primary-side voltage, the primary-side current, the secondary-side voltage, and the secondary-side current, and to adjust the operating frequency of the primary-side full-bridge converter based on the ZVS angle and the system efficiency.

[0078] Specifically, the DSP controller 8 receives WiFi signals from the primary-side signal sampling module and the secondary-side signal sampling module via a serial port. The DSP controller 8 calculates the ZVS angle based on the primary-side voltage and the primary-side current, and calculates the system efficiency based on the primary-side voltage, the primary-side current, the secondary-side voltage, and the secondary-side current.

[0079] The calculation process of the ZVS angle in this invention is as follows: Figure 4 As shown, the primary side voltage and primary side current are transmitted via WiFi to the DSP controller 8 to calculate the ZVS angle. ZVS angle is short for zero-voltage switching, and the ZVS angle calculation expression is:

[0080]

[0081]

[0082]

[0083] Where θ is the ZVS angle, θ1 is the primary voltage phase angle, θ2 is the primary current phase angle, Z is the input impedance, X is the imaginary part of the input impedance, R is the real part of the input impedance, and j is the imaginary number. A voltage phasor value, possessing two attributes: amplitude and phase. U is the current phasor value, possessing two attributes: amplitude and phase. The phase, I is The phase.

[0084] The input impedance Z is a fixed value based on system parameters and can be obtained by the following formula:

[0085] Z{(((L s ||C1+C inv )||C 11 )+C m )||C 12 +C rec )||C2+L2+R eq )}=R+jX;

[0086] In this context, || indicates parallel connection, and + indicates series connection.

[0087] Furthermore, the underwater single-capacitor wireless power transmission system also includes a drive circuit, which is located between the DSP controller 8 and the inverter circuit 2. The drive circuit is used to receive the PWM signal sent by the DSP controller 8 and amplify the power to provide driving force for the switching devices in the inverter circuit 2.

[0088] This invention transmits the primary-side voltage, primary-side current, secondary-side voltage, and secondary-side current to the WiFi module of the DSP controller 8 via a primary-side WiFi module and a secondary-side WiFi module, thereby eliminating the interference of the power circuit on the control circuit during signal transmission.

[0089] The equivalent circuit of the underwater single-capacitor wireless power transfer system provided by this invention is as follows: Figure 5 As shown. Figure 5 Middle,U s For a high-frequency inverter circuit considering only the fundamental frequency as the equivalent AC voltage source, R eq This is the equivalent resistance of the high-frequency rectifier circuit. Among them, U d R represents the magnitude of the DC power supply. L This refers to the size of the load.

[0090] Figure 5 In the middle, C 11 C is the capacitance to ground of the primary energy transmitting plate. 12 C represents the capacitance to ground of the secondary energy receiving electrode. m The equivalent coupling capacitance between the primary energy transmitting plate and the secondary energy receiving plate can be measured using an LCR meter.

[0091] This invention samples the voltage and current at the energy transmitting and receiving ends and recalculates the optimal operating frequency of the inverter circuit 2 using a preset algorithm. Then, the switching frequency of the inverter circuit 2 is adjusted via a WiFi signal to achieve optimal system efficiency. This enables efficient and stable wireless power transmission in various underwater environments.

[0092] The following describes the workflow of the automatic tuning method for underwater single-capacitor wireless power transfer provided by this invention, such as... Figure 6 As shown.

[0093] First, select a suitable electrode distance and measure the values ​​of the two self-capacitance and mutual capacitance of the energy transmission electrode 4. Then, select appropriate compensation parameters according to the transmission requirements to build a wireless power transmission system.

[0094] Secondly, a primary-side signal sampling module is connected to the input of the primary-side full-bridge converter, and a secondary-side signal sampling module is connected to the output of the secondary-side full-bridge converter. The voltage and current are transmitted to the DSP controller 8 through the primary-side WiFi module and the secondary-side WiFi module.

[0095] Finally, after pressing the automatic frequency adjustment switch, the DSP controller 8 modifies the operating frequency of the primary-side full-bridge converter according to the pre-stored built-in frequency list. At the same time, after each frequency modification, the DSP controller 8 receives the primary-side voltage, primary-side current, secondary-side voltage, and secondary-side current, calculates the ZVS angle through a preset algorithm, stores it, and then selects the optimal efficiency and the best ZVS angle for power transmission according to the scanned frequency list, thus realizing the automation process.

[0096] Specifically, (1) when the automatic tuning button is pressed, the inverter circuit 2 starts working at the initial frequency. At the same time, the DSP controller 8 has multiple built-in frequency points.

[0097] (2) Acquire primary side voltage Primary side current Secondary voltage and secondary current The primary-side voltage, primary-side current, secondary-side voltage, and secondary-side current are transmitted to the DSP controller 8 via WiFi. The DSP controller 8 records the primary-side voltage, primary-side current, secondary-side voltage, and secondary-side current over a fixed time period at this frequency, and calculates the ZVS angle and system efficiency under the current system environment based on the primary-side voltage, primary-side current, secondary-side voltage, and secondary-side current.

[0098] The ZVS angle θ is a parameter related to system efficiency. If θ is negative, it can be considered that the switching losses of the entire system are relatively large, and the overall system efficiency is low. Therefore, by calculating the ZVS angle and system efficiency, a better operating frequency can be selected.

[0099] (3) The DSP controller 8 adjusts the frequency according to the built-in frequency point. For example, if the initial frequency is 200kHz and the built-in frequency point range is 180kHz~210kHz, it first adjusts downward with a step size of 1kHz. After reaching 180kHz, it adjusts from 201kHz to 210kHz. The process of (2) is repeated after each frequency adjustment.

[0100] (4) The DSP controller 8 determines whether all built-in frequency points have been traversed. If the determination is true, the DSP controller 8 selects the optimal inverter circuit operating frequency based on the ZVS angle and system efficiency at each frequency. Then, the DSP controller 8 continuously outputs the PWM signal corresponding to the optimal inverter circuit operating frequency. Specifically, the operating frequency with the highest system efficiency when the ZVS angle is within 15° is selected as the optimal inverter circuit operating frequency. Generally, controlling the ZVS angle within 15° can effectively reduce the losses of the switching transistors.

[0101] (5) If the judgment is false, the DSP controller 8 repeats (2) to (4), repeating the process of calculating the ZVS angle and judging the built-in frequency points.

[0102] In addition, the ZVS angle and system efficiency can be calculated via the host computer 9. Users can manually send the frequency to the DSP controller 8 each time via the host computer 9, and the output will be based on the set frequency. Alternatively, the host computer 9 can also set the built-in frequency point of the DSP controller 8 via WiFi, thereby modifying the frequency range traversed by the DSP controller 8.

[0103] This invention uses four WiFi modules for networking, such as Figure 7 As shown, the signal sampling module, host computer, and DSP controller interact via a WiFi module. The WiFi module on the DSP controller is set to AP mode, essentially acting as a hotspot to provide wireless access, allowing other wireless devices to connect and access data. The WiFi modules on the host computer and signal sampling module are set to STA mode, with the AP at the center. Communication between STAs is relayed through the AP, facilitating the expansion of sensors or other peripherals. Based on the characteristics of a single-capacitor wireless power transmission system, this invention uses a WiFi network as the transmission medium for sensor data, reducing power loss caused by stray capacitance crosstalk in voltage and current sensors.

[0104] In summary, this invention can automatically adjust the operating frequency of the inverter circuit when system parameters change under environmental conditions, reducing the system efficiency and power degradation caused by traditional wired control, and enabling long-distance, high-efficiency, and stable wireless power supply for underwater devices in different environments.

[0105] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. An underwater single-capacitor wireless power transfer system, characterized in that, The underwater single-capacitor wireless power transmission system includes: a power supply, a load, a primary-side full-bridge converter, a secondary-side full-bridge converter, an energy transmission plate, a primary-side signal sampling module, a secondary-side signal sampling module, and a DSP controller. The power supply, the primary-side full-bridge converter, the energy transmission plate, the secondary-side full-bridge converter, and the load are connected in sequence to transmit the current from the power supply to the load. The primary-side signal sampling module is connected to the primary-side full-bridge converter, and the primary-side signal sampling module is used to collect the primary-side voltage and primary-side current. The secondary-side signal sampling module is connected to the secondary-side full-bridge converter, and the secondary-side signal sampling module is used to collect the secondary-side voltage and secondary-side current. Both the primary-side signal sampling module and the secondary-side signal sampling module transmit the primary-side voltage, the primary-side current, the secondary-side voltage, and the secondary-side current to the DSP controller via WiFi; The DSP controller is connected to the primary-side full-bridge converter. The DSP controller is used to calculate the ZVS angle and system efficiency based on the primary-side voltage, the primary-side current, the secondary-side voltage, and the secondary-side current, and to adjust the operating frequency of the primary-side full-bridge converter based on the ZVS angle and the system efficiency.

2. The underwater single-capacitor wireless power transmission system according to claim 1, characterized in that, The energy transmission plate includes a primary energy transmitting plate and a secondary energy receiving plate. The primary-side energy transmitting plate is connected to the primary-side full-bridge converter; the secondary-side energy receiving plate is connected to the secondary-side full-bridge converter. There is a set distance between the primary energy transmitting electrode and the secondary energy receiving electrode.

3. The underwater single-capacitor wireless power transmission system according to claim 2, characterized in that, The power supply is a DC power supply; the primary-side full-bridge converter includes an inverter circuit and a primary-side compensation network; The inverter circuit is connected to the DC power supply and the primary-side compensation network respectively. The primary-side compensation network is also connected to the primary-side energy transmitting plate. The primary-side compensation network and the primary-side energy transmitting plate form a primary-side resonant circuit to minimize reactive power in the primary-side circuit. The primary-side signal sampling module is located between the inverter circuit and the primary-side compensation network to collect the primary-side voltage and primary-side current. The DSP controller is connected to the inverter circuit. The DSP controller generates a PWM signal based on the ZVS angle and the system efficiency to adjust the operating frequency of the inverter circuit.

4. The underwater single-capacitor wireless power transmission system according to claim 3, characterized in that, The primary-side compensation network includes a first inductor and a first capacitor; The first output terminal of the inverter circuit is connected to one end of the first inductor, and the second output terminal of the inverter circuit is connected to one end of the first capacitor; the other end of the first inductor is connected to the primary side energy transmitting plate; the other end of the first capacitor is connected between the first inductor and the primary side energy transmitting plate.

5. The underwater single-capacitor wireless power transmission system according to claim 4, characterized in that, The primary-side signal sampling module includes a primary-side voltage divider resistor, a primary-side voltage sensor, a primary-side current sensor, and a primary-side WiFi module; the primary-side WiFi module is in client mode; the WiFi module in the DSP controller is in AP mode. One end of the primary-side voltage divider resistor is connected between the first output terminal of the inverter circuit and the first inductor, and the other end of the primary-side voltage divider resistor is connected to the primary-side voltage sensor. The primary-side current sensor is connected to the second output terminal of the inverter circuit, the primary-side voltage sensor, and the first capacitor, respectively. The primary-side voltage divider resistor is used to divide the voltage output by the inverter circuit; the primary-side voltage sensor is used to collect the primary-side voltage; the primary-side current sensor is used to collect the primary-side current; and the primary-side WiFi module is used to send the primary-side voltage and the primary-side current to the WiFi module in the DSP controller.

6. The underwater single-capacitor wireless power transmission system according to claim 2, characterized in that, The secondary-side full-bridge converter includes a secondary-side compensation network and a rectifier circuit. The rectifier circuit is connected to the secondary-side compensation network and the load respectively. The secondary-side compensation network is also connected to the secondary-side energy receiving plate. The secondary-side compensation network and the secondary-side energy receiving plate form a secondary-side resonant circuit, which minimizes the reactive power in the secondary-side circuit. The secondary-side signal sampling module is located between the secondary-side compensation network and the rectifier circuit to collect the secondary-side voltage and secondary-side current.

7. The underwater single-capacitor wireless power transmission system according to claim 6, characterized in that, The secondary-side compensation network includes a second inductor and a second capacitor; The first input terminal of the rectifier circuit is connected to one end of the second inductor, and the second input terminal of the rectifier circuit is connected to one end of the second capacitor; the other end of the second inductor is connected to the secondary side energy receiving plate; the other end of the second capacitor is connected between the second inductor and the secondary side energy receiving plate.

8. The underwater single-capacitor wireless power transmission system according to claim 7, characterized in that, The secondary-side signal sampling module includes a secondary-side voltage divider resistor, a secondary-side voltage sensor, a secondary-side current sensor, and a secondary-side WiFi module; the secondary-side WiFi module is in client mode; the WiFi module in the DSP controller is in AP mode. One end of the secondary-side voltage divider resistor is connected between the first input terminal of the rectifier circuit and the second inductor, and the other end of the secondary-side voltage divider resistor is connected to the secondary-side voltage sensor. The secondary current sensor is connected to the second input terminal of the rectifier circuit, the secondary voltage sensor, and the second capacitor, respectively. The secondary-side voltage divider resistor is used to divide the voltage input to the rectifier circuit; the secondary-side voltage sensor is used to acquire the secondary-side voltage; the secondary-side current sensor is used to acquire the secondary-side current. The secondary-side WiFi module is used to send the secondary-side voltage and the secondary-side current to the WiFi module in the DSP controller.

9. The underwater single-capacitor wireless power transmission system according to claim 1, characterized in that, The DSP controller calculates the ZVS angle based on the primary side voltage and the primary side current, and calculates the system efficiency based on the primary side voltage, the primary side current, the secondary side voltage, and the secondary side current.

10. An automatic tuning method for underwater single-capacitor wireless power transfer, applied to the underwater single-capacitor wireless power transfer system according to any one of claims 1 to 9, characterized in that, The automatic tuning method includes: The DSP controller adjusts the operating frequency of the primary-side full-bridge converter according to a pre-stored built-in frequency list; For any operating frequency of the primary-side full-bridge converter, the primary-side voltage and primary-side current are collected by the primary-side signal sampling module and transmitted to the DSP controller via WiFi; the secondary-side voltage and secondary-side current are collected by the secondary-side signal sampling module and transmitted to the DSP controller via WiFi. The DSP controller calculates the ZVS angle and system efficiency of the primary-side full-bridge converter at the operating frequency based on the primary-side voltage, the primary-side current, the secondary-side voltage, and the secondary-side current. The DSP controller determines the optimal system frequency and the best ZVS angle based on the ZVS angle and system efficiency of the primary-side full-bridge converter at each operating frequency, and controls the primary-side full-bridge converter to transmit power according to the operating frequency corresponding to the optimal system frequency and the best ZVS angle.

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