EVDWPT ground control box group power synchronization method based on optical fiber synchronization frequency modulation

Abstract

The invention discloses an EVDWPT ground control box group power synchronization method based on optical fiber synchronous frequency modulation. The method comprises the steps that a vehicle-mounted end sends a square wave signal containing a power level to a power supply cabinet through a signal transmitter; the power supply cabinet analyzes the power level in the square wave signal, generates a cooperative control signal containing a synchronous pulse frequency fine tuning instruction and a phase shift angle adjusting instruction, obtains the current guide rail position of the vehicle emitting the square wave signal, and sends the cooperative control signal to the inverter box corresponding to the guide rail position; the inverter box adjusts the working frequency to the target frequency according to the synchronous pulse frequency fine tuning instruction, and adjusts the phase difference between the output voltage fundamental wave and the current according to the phase shift angle adjusting instruction; and the inverter box drives the corresponding transmitting coil according to the adjusted target frequency and the phase shift angle so as to output power matched with the power level to the vehicle-mounted end receiving coil, so that the vehicle power matching requirement is met. According to the invention, while compatible charging of the multi-power-level vehicle is realized, soft switching starting of the inverter can be ensured.

Description

Technical Field

[0001] This invention relates to the field of wireless power transmission technology, and in particular to a power synchronization method for EVDWPT ground control box groups based on fiber optic synchronous frequency modulation. Background Technology

[0002] Wireless Power Transfer (WPT) technology integrates theoretical technologies from fields such as power electronics and automatic control. It utilizes carriers such as electric fields, magnetic fields, microwaves, or lasers to enable the transfer of electrical energy between the power grid / battery and electrical equipment through loose coupling and non-contact methods.

[0003] In the large-scale application of Dynamic Wireless Charging (DWPT) technology for electric vehicles, several interoperability issues arise. Vehicles of different brands, models, and power ratings on the road have varying charging needs and states. Especially when vehicles cross adjacent guide rail boundaries, if the transmission power levels of the front and rear guide rails cannot be accurately synchronized with the core magnetic field phase in real time, severe phase mismatch and dead-zone effects will occur, resulting in decreased energy transfer efficiency. Traditional solutions relying on independent communication between the vehicle-mounted unit and each ground inverter unit are complex and have high latency, making it difficult to meet the requirements of dynamic seamless charging. However, for electric vehicles of different power types, the inverter should transmit different power levels. If the vehicle-mounted unit needs to communicate with each inverter circuit, the complexity of communication will increase significantly.

[0004] Meanwhile, during system startup or critical rail switching operations, hard-switching power devices experience extremely high switching stress, resulting in significant switching losses and strong electromagnetic interference. This not only directly reduces system efficiency but also leads to power fluctuations, voltage overshoot, and current oscillations, threatening system stability and device lifespan, becoming a serious performance bottleneck in scenarios with frequent start-stop and switching during dynamic charging. Furthermore, when electric vehicles of different power types are traveling on the same road segment, the inverter can only emit one power level, failing to simultaneously meet the charging needs of electric vehicles with different power levels. Summary of the Invention

[0005] This invention aims to at least partially solve the technical problems in related technologies. Therefore, the first objective of this invention is to provide a power synchronization method for EVDWPT ground control box groups based on fiber optic synchronous frequency modulation. This method, by coordinating the dynamic matching of the synchronization pulse frequency and phase shift angle, achieves compatible charging for vehicles of multiple power levels while ensuring soft-switching startup of the inverter, thereby reducing switching losses, improving system efficiency, and enhancing electromagnetic compatibility.

[0006] The second objective of this invention is to provide an EVDWPT system.

[0007] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0008] A power synchronization method for EVDWPT ground control box groups based on fiber optic synchronous frequency modulation is applied to an EVDWPT system. The system includes a vehicle-mounted terminal and a ground power supply module. The vehicle-mounted terminal includes a receiving coil and a signal transmitter. The ground power supply module includes a power cabinet connected in parallel with the power grid and multiple segmented inverter boxes controlled by the power cabinet. Each inverter box is connected to a corresponding transmitting coil. The method includes:

[0009] The vehicle-mounted unit sends a square wave signal containing the power level to the power cabinet via a signal transmitter;

[0010] The power cabinet analyzes and identifies the power level in the square wave signal, generates a coordinated control signal containing a synchronization pulse frequency fine-tuning command and a phase shift angle adjustment command, obtains the current guide rail position of the vehicle emitting the square wave signal, and sends the coordinated control signal to the inverter box corresponding to the guide rail position.

[0011] The inverter box receives the coordinated control signal and adjusts the operating frequency to the target frequency according to the synchronization pulse frequency fine-tuning command, and synchronously adjusts the phase difference between the fundamental wave of the output voltage and the current according to the phase shift angle adjustment command.

[0012] The inverter box drives the corresponding transmitting coil according to the adjusted target frequency and phase shift angle to output power to the vehicle-mounted receiving coil that matches the power level, so as to meet the vehicle power matching requirements.

[0013] In one possible implementation, a clock signal source is provided inside the power cabinet, and the method further includes: the clock signal source transmitting a unified clock signal to multiple segmented inverter boxes via optical fiber.

[0014] In one possible implementation, the inverter box is equipped with a full-bridge inverter and a primary-side compensation network, and the vehicle-mounted terminal further includes a secondary-side compensation network and a full-bridge rectifier. The inverter box, the corresponding transmitting coil, and the vehicle-mounted terminal form a dual LCC resonant converter. The method further includes soft-switching state verification, which includes:

[0015] The imaginary part of the primary-side equivalent impedance of the dual LCC resonant converter is determined based on the adjusted target frequency.

[0016] Determine whether the imaginary part of the primary-side equivalent impedance is greater than zero;

[0017] If the value is greater than zero, the phase shift angle is maintained to enable soft start of the inverter; otherwise, the process returns to the step of regenerating the phase shift angle adjustment command.

[0018] In one possible implementation, vehicles with different power ratings send square wave signals of different frequencies through corresponding on-board terminals.

[0019] In one possible implementation, the output power modeling process of the inverter box includes:

[0020] Based on Kirchhoff's voltage law, the voltage equations for each loop of the primary and secondary sides are derived from the dual-LCC equivalent circuit of the dual-LCC resonant converter.

[0021] The output current of the dual LCC resonant converter is determined based on each voltage equation.

[0022] The output power of the dual LCC resonant converter is determined based on the output current and the equivalent impedance of the load, and a three-dimensional mapping relationship between the output power, operating frequency, and phase shift angle is established, wherein the output power is used to characterize the output power of the inverter box.

[0023] In one possible implementation, the primary-side equivalent impedance modeling process includes:

[0024] Determine the secondary-side equivalent impedance and reflection impedance of the dual LCC resonant converter;

[0025] The primary side equivalent impedance is determined based on the secondary side equivalent impedance and the reflection impedance, so as to obtain the mapping relationship between the primary side equivalent impedance and the operating frequency.

[0026] To achieve the above objectives, a second aspect of the present invention provides an EVDWPT system, comprising:

[0027] The vehicle-mounted unit includes a receiving coil and a signal transmitter that transmits square wave signals to the power supply cabinet.

[0028] The ground power supply module includes a power cabinet connected in parallel with the power grid and multiple segmented inverter boxes controlled by the power cabinet, each inverter box being connected to a corresponding transmitting coil; wherein, the power cabinet includes:

[0029] A clock signal source is used to transmit a unified clock signal to multiple segmented inverter boxes via optical fiber.

[0030] The collaborative control module receives square wave signals, analyzes the power level, generates commands including synchronization pulse frequency fine-tuning and phase angle adjustment, and transmits the two commands to the target inverter box so that the target inverter box can adjust the operating frequency and phase angle according to the two commands to achieve vehicle power matching.

[0031] In one possible implementation, the collaborative control module is also used to verify the imaginary part of the target inverter box output impedance in real time, wherein the target inverter box output impedance is the primary-side equivalent impedance of the dual LCC resonant converter.

[0032] In one possible implementation, the frequency of the square wave signal transmitted by the vehicle-mounted terminal corresponds to the power level of the corresponding vehicle.

[0033] In one possible implementation, the power cabinet further includes a modeling module for modeling the output power and output impedance of the inverter box.

[0034] This invention has at least the following technical effects:

[0035] This invention provides a power synchronization method for EVDWPT ground control box groups based on fiber optic synchronous frequency modulation. Specifically, the vehicle-mounted terminal sends a square wave signal containing power levels to the power cabinet via a signal transmitter. The power cabinet analyzes and identifies the power levels in the square wave signal. Then, based on the three-dimensional mapping relationship between output power, operating frequency, and phase shift angle obtained from the inverter box output power modeling results, it generates a coordinated control signal containing synchronous pulse frequency fine-tuning commands and phase shift angle adjustment commands. Next, it obtains the current guide rail position of the vehicle transmitting the square wave signal and sends the coordinated control signal to the inverter box corresponding to that guide rail position. After receiving the coordinated control signal, the inverter box adjusts its operating frequency to the target frequency according to the synchronous pulse frequency fine-tuning command, and synchronously adjusts the phase difference between the fundamental frequency and current of the output voltage according to the phase shift angle adjustment command. This facilitates driving the corresponding transmitting coil according to the adjusted target frequency and phase shift angle, achieving vehicle power matching requirements. Furthermore, a unified clock signal is transmitted via fiber optic cable to multiple segmented inverter boxes through a clock signal source set in the power cabinet, ensuring strict phase alignment of the magnetic field of each transmitting coil segment, avoiding phase mismatch and reduced energy transmission efficiency. Simultaneously, the imaginary part of the target inverter box's output impedance is verified in real time to ensure that the adjusted phase shift angle meets the inverter's soft-start conditions. Therefore, this invention utilizes a clock signal source to transmit signals via optical fiber, which improves transmission speed, facilitates interaction between the electric vehicle and the inverter circuit while ensuring full inverter startup. It also avoids phase mismatch, improves interoperability, reduces switching losses, enhances system efficiency, system stability, and device lifespan, and enables power matching for different vehicles.

[0036] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the structure of a dynamic wireless charging system for electric vehicles according to an embodiment of the present invention.

[0038] Figure 2 This is a flowchart of the EVDWPT ground control box group power synchronization method based on optical fiber synchronous frequency modulation, according to an embodiment of the present invention.

[0039] Figure 3 This is a flowchart of a two-degree-of-freedom cooperative control strategy system according to an embodiment of the present invention.

[0040] Figure 4 This is the equivalent circuit diagram of dual LCC in an embodiment of the present invention.

[0041] Figure 5 This is a diagram showing the power-frequency-phase-angle output relationship according to an embodiment of the present invention.

[0042] Figure 6 This is a schematic diagram of the full-bridge circuit of the dual LLC resonant converter according to an embodiment of the present invention.

[0043] Figure 7 The impedance Z in this embodiment of the invention P Graph showing the relationship between the imaginary part and frequency.

[0044] Figure 8 This is a waveform diagram of the 10kW power output in an embodiment of the present invention.

[0045] Figure 9 This is a waveform diagram of the 20kW power output in an embodiment of the present invention.

[0046] Figure 10 This is a waveform diagram of the 30kW power output in an embodiment of the present invention.

[0047] Figure 11 This is a waveform diagram of the 10kW voltage and current output in an embodiment of the present invention.

[0048] Figure 12 This is a waveform diagram of the 20kW voltage and current output of an embodiment of the present invention.

[0049] Figure 13 This is a waveform diagram of the 30kW voltage and current output in an embodiment of the present invention. Detailed Implementation

[0050] The following describes this embodiment in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the invention, and should not be construed as limiting the invention.

[0051] The segmented dynamic wireless charging system for electric vehicles (EVs) employs several sets of energy transmitting devices at its transmitter, each with its own resonant network, capable of independent operation. The efficiency of energy reception during EV operation is related to the density of the energy transmitting coils, and the phase difference between adjacent transmitting coils significantly impacts output power. When the phase difference is 180°, the system's output power can even be zero. Furthermore, when EVs travel on dynamic wireless charging routes, different types of EVs inevitably travel on the same route, making communication between the vehicle-mounted terminal and the inverter circuit extremely difficult. Therefore, this embodiment designs a power synchronization method for EVDWPT ground control boxes based on fiber optic synchronous frequency modulation. It adopts a dual-degree-of-freedom collaborative control strategy of frequency and directional angle. By changing the system's operating frequency, the system's transmission characteristics are adjusted to match the power requirements of different vehicles. Simultaneously, while changing the frequency to match the power, the phase angle between the inverter's output voltage fundamental and current is adjusted to ensure the inverter starts under zero-voltage switching or near-zero-voltage switching conditions, thereby significantly reducing switching losses.

[0052] The following description, with reference to the accompanying drawings, illustrates the EVDWPT ground control box group power synchronization method based on fiber optic synchronous frequency modulation in this embodiment.

[0053] It should be noted that the EVDWPT ground control box group power synchronization method based on fiber optic synchronous frequency modulation in this embodiment is applied to EVDWPT (Electric Vehicle Dynamic Wireless Power Transmission System). This system includes an on-board unit and a ground power supply module. The on-board unit includes a receiving coil and a signal transmitter. Figure 1 As shown, the ground power supply module includes a power cabinet connected in parallel with the power grid and multiple segmented inverter boxes controlled by the power cabinet. Each inverter box is connected to a corresponding transmitting coil.

[0054] Figure 2 This is a flowchart illustrating the EVDWPT ground control box group power synchronization method based on fiber optic synchronous frequency modulation, according to an embodiment of the present invention. Figure 2 As shown, the method includes:

[0055] Step S101: The vehicle-mounted unit sends a square wave signal containing the power level to the power cabinet via a signal transmitter.

[0056] Specifically, vehicles traveling on the road may include vehicles of different power levels. Therefore, this embodiment can transmit square wave signals of different frequencies through the corresponding vehicle-mounted terminal.

[0057] Step S102: The power cabinet analyzes and identifies the power level in the square wave signal, generates a cooperative control signal containing a synchronization pulse frequency fine-tuning command and a phase shift angle adjustment command, obtains the current guide rail position of the vehicle emitting the square wave signal, and sends the cooperative control signal to the inverter box corresponding to the guide rail position.

[0058] Specifically, after receiving a square wave signal, the power cabinet analyzes its frequency to obtain the corresponding power level, and then identifies the power level within the square wave signal. After identifying the power level, it determines the target frequency and phase shift angle based on the three-dimensional mapping relationship generated during the inverter's output power modeling process in subsequent steps. Then, based on the determined target frequency and phase shift angle, it generates a coordinated control signal containing synchronization pulse frequency fine-tuning commands and phase shift angle adjustment commands.

[0059] Simultaneously, the current position of the vehicle emitting the square wave signal on the guide rail is obtained. In one embodiment, the current guide rail position information of the vehicle can be sent by the on-board unit, or it can be sent by the ground power supply module, i.e., the ground unit.

[0060] For example, when transmitting to a vehicle-mounted terminal, the vehicle-mounted terminal can identify the current rail number in real time and then send the number to the power supply cabinet. The power supply cabinet can then identify the current rail position of the vehicle transmitting the square wave signal based on the number, thereby activating the corresponding inverter box. When transmitting to a ground-based terminal, each inverter box can be equipped with a positioning module. This module identifies the square wave signal transmitted by a vehicle above it and its frequency, sending this frequency information to the power supply cabinet. The power supply cabinet compares the frequency transmitted by the vehicle-mounted terminal with that transmitted by the ground-based positioning module. If they match, the power supply cabinet binds the corresponding vehicle to the rail where the positioning module is located, thus binding the vehicle to the corresponding inverter box. The power supply cabinet can then directly activate the inverter box corresponding to that rail. Alternatively, other methods can be used for position identification. For instance, the ground-based positioning module can identify vehicle tag information, and the power supply cabinet can also identify the vehicle tag information by analyzing the frequency. This tag information identification binds the corresponding vehicle to the rail where the positioning module is located, thereby binding the vehicle to the corresponding inverter box.

[0061] After obtaining the current position of the vehicle transmitting the square wave signal on the guide rail, the power cabinet can send a coordinated control signal to the inverter box corresponding to the guide rail position.

[0062] The above-mentioned inverter box output power modeling process includes: listing the voltage equations of each loop on the primary and secondary sides based on Kirchhoff's voltage law according to the dual LCC equivalent circuit of the dual LCC resonant converter; determining the output current of the dual LCC resonant converter based on each voltage equation; determining the output power of the dual LCC resonant converter based on the output current and the load equivalent impedance, and establishing a three-dimensional mapping relationship between output power, operating frequency, and phase shift angle, wherein the output power is used to characterize the output power of the inverter box.

[0063] It should be noted that the modeling process will be explained in detail later.

[0064] In one embodiment of the present invention, the inverter box is equipped with a full-bridge inverter and a primary-side compensation network, and the vehicle-mounted end also includes a secondary-side compensation network and a full-bridge rectifier. The inverter box, the corresponding transmitting coil, and the vehicle-mounted end form a dual LCC (a type of resonant compensation network) resonant converter. The method further includes soft-switching state verification, which includes: determining the imaginary part of the primary-side equivalent impedance of the dual LCC resonant converter according to the adjusted target frequency; determining whether the imaginary part of the primary-side equivalent impedance is greater than zero; if it is greater than zero, maintaining the phase shift angle to achieve soft start of the inverter; otherwise, returning to the step of regenerating the phase shift angle adjustment command.

[0065] Specifically, after determining the target frequency and phase shift angle, the power supply cabinet needs to verify the phase shift angle to determine whether phase shift control at that target frequency using that phase shift angle can achieve inverter soft start. Therefore, after calculating the target frequency, the imaginary part of the primary equivalent impedance corresponding to the target frequency can be determined based on the mapping relationship between the primary equivalent impedance obtained from the primary equivalent impedance modeling process and the operating frequency. If the corresponding imaginary part of the primary equivalent impedance is greater than zero, the phase shift angle is maintained to achieve inverter soft start; otherwise, the power supply cabinet regenerates the phase shift angle to satisfy inverter soft start.

[0066] In one possible implementation, the primary-side equivalent impedance modeling process includes: determining the secondary-side equivalent impedance and reflection impedance of the dual LCC resonant converter; and determining the primary-side equivalent impedance based on the secondary-side equivalent impedance and reflection impedance to obtain the mapping relationship between the primary-side equivalent impedance and the operating frequency.

[0067] The modeling process for the primary-side equivalent impedance will be explained later.

[0068] In one possible implementation, a clock signal source is installed inside the power cabinet, and the method further includes: the clock signal source transmitting a unified clock signal to multiple segmented inverter boxes via optical fiber.

[0069] In this embodiment, a unified clock signal is transmitted via optical fiber to multiple segmented inverter boxes through a clock signal source located in the power cabinet. This ensures that the magnetic field phases of the transmitting coils in each segment are strictly aligned and synchronized, avoiding phase mismatch and thus reducing energy transmission efficiency. Alternatively, the coordinated control signal in this embodiment can also be transmitted via optical fiber to improve transmission speed and facilitate interaction between the electric vehicle and the inverter circuit while ensuring full inverter startup.

[0070] Step S103: The inverter receives the coordinated control signal, adjusts the operating frequency to the target frequency according to the synchronization pulse frequency fine-tuning command, and synchronously adjusts the phase difference between the fundamental wave of the output voltage and the current according to the phase shift angle adjustment command.

[0071] Step S104: The inverter box drives the corresponding transmitting coil according to the adjusted target frequency and phase shift angle to output power to the vehicle receiving coil that matches the power level, so as to meet the vehicle power matching requirements.

[0072] In this embodiment, the structure of the dynamic wireless charging system for electric vehicles is shown in the diagram below. Figure 1 As shown, AC power is supplied to the power cabinet from the power grid. After passing through the power cabinet, DC power is input to the inverter box. The inverter box provides energy to the transmitting coil underground. Simultaneously, the receiving coil located at the electric vehicle receives the energy and provides it to the electric vehicle. In this embodiment, the power cabinet is equipped with a clock signal source, and the vehicle-mounted unit is equipped with a signal transmitter. When the vehicle-mounted unit travels to this road segment, it sends square wave signals of different frequencies to the power cabinet. After receiving the signal, the power cabinet quickly determines the power level required by the vehicle-mounted unit and transmits the corresponding power level signal to the inverter box, thereby enabling the inverter box to provide the corresponding power level of electrical energy to the transmitting coil.

[0073] The modeling process described above will be explained in detail below.

[0074] The flowchart of the two-degree-of-freedom collaborative control strategy system for operating frequency and shift angle proposed in this embodiment is as follows: Figure 3 As shown. This embodiment addresses a dual-LCC topology wireless power transfer system (the dual-LCC equivalent circuit of the dual-LCC resonant converter is shown in the figure). Figure 4 As shown, this paper proposes a method based on a combination of frequency modulation and phase shifting to match dynamic charging of different vehicle power levels and the soft-switching startup of the inverter during dynamic wireless charging. The core of this method is to establish the relationship between output power, operating frequency, and phase shift angle. For different target vehicle power levels, a suitable set of operating frequencies and phase shift angles is determined. The operating frequency is responsible for accurately matching the power demand, while the phase shift angle is responsible for ensuring the soft-switching conditions of the inverter at that power point.

[0075] Analyzing the equivalent circuit diagram of the dual-LCC resonant converter, the following set of voltage equations can be derived according to Kirchhoff's Voltage Law (KVL):

[0076]

[0077] Among them, U AB For the direct output voltage of the inverter, I1, I p I s I2 and I3 represent the inverter's direct output current, the current on the primary side transmitting coil, the current on the secondary side receiving coil, and the rectified output current, respectively. f1 C f C p M, L s C s Cf2 L f2 Req and w represent the primary-side compensating inductance, primary-side parallel compensating capacitor, primary-side series compensating capacitor, coil mutual inductance, receiving coil self-inductance, secondary-side series compensating capacitor, secondary-side parallel compensating capacitor, secondary-side compensating inductance, load equivalent impedance, and system angular frequency, respectively.

[0078] The rectified output current I2 and the output power P can be calculated using the above set of equations.

[0079]

[0080] Substituting the output current I2 into the power expression, we can obtain a three-dimensional graph showing the relationship between the output power P and the operating frequency f and the phase shift angle β, as shown below. Figure 5 As shown. By understanding the relationship between output power, operating frequency, and phase shift angle, the range of operating frequency and phase shift angle corresponding to different vehicle power can be quickly determined. Then, the operating frequency f and phase shift angle β corresponding to different vehicle power can be calculated, thereby realizing the functions of segmented rail power matching and inverter soft start.

[0081] Furthermore, by analyzing the full-bridge circuit of the dual LLC resonant converter (schematic diagram as shown in Figure 1), Figure 6 From the relationship shown, the primary-side equivalent impedance Z can be obtained. P The relationship with the operating frequency, where Z S For the secondary side equivalent impedance, Z r Let be the reflection impedance. Through analysis, the relationship between the three can be easily derived as follows:

[0082]

[0083] Among them, L p This is the self-inductance of the transmitting coil.

[0084] Finally, based on Z P The expression relating the operating frequency f to the primary equivalent impedance Z is used to establish the relationship between the primary and operating frequencies. P A two-dimensional graph showing the relationship between the imaginary part and the operating frequency, as shown below. Figure 7 As shown.

[0085] By analyzing the sign of the imaginary part of the primary-side equivalent impedance, it is possible to determine whether the inverter is in a soft-start state. When the imaginary part is positive, the system is inductive and in soft-start mode; when the imaginary part is negative, the system is capacitive and in hard-start mode. This allows for rapid analysis of the phase shift angle range after calculating the operating frequency f that matches the vehicle power, thus enabling faster calculation of the phase shift angle that satisfies soft-start requirements.

[0086] Through calculation and analysis, the operating frequency f and phase shift angle β matched with different vehicle loads can be obtained. Here, the operating frequency f and phase shift angle β of three different power vehicle loads are calculated. The corresponding operating frequency f and phase shift angle β of other power loads can be obtained by following the same method.

[0087] When the vehicle load power is 10kW, the corresponding operating frequency is f = 82kHz and the phase shift angle β = 72°; when the vehicle load power is 20kW, the corresponding operating frequency is f = 85kHz and the phase shift angle β = 0°; when the vehicle load power is 30kW, the corresponding operating frequency is f = 89kHz and the phase shift angle β = 93°; the power output waveforms for the three power loads are as follows: Figure 8-10 As shown, the voltage and current output waveforms are as follows: Figure 11-13 As shown.

[0088] Analysis of the voltage and current output waveforms and the power output waveforms reveals that the system's impedance characteristics are inductive, which satisfies the inverter's soft-start requirement and the output power matching the vehicle-end power, thus achieving the functions of dynamic matching of vehicle-end power and inverter soft-start.

[0089] Furthermore, the present invention also provides an EVDWPT system, comprising:

[0090] The vehicle-mounted unit includes a receiving coil and a signal transmitter that transmits square wave signals to the power supply cabinet.

[0091] The ground power supply module includes a power cabinet connected in parallel with the power grid and multiple segmented inverter boxes controlled by the power cabinet, each inverter box being connected to a corresponding transmitting coil; wherein, the power cabinet includes:

[0092] A clock signal source is used to transmit a unified clock signal to multiple segmented inverter boxes via optical fiber.

[0093] The collaborative control module receives square wave signals, analyzes the power level, generates commands including synchronization pulse frequency fine-tuning and phase angle adjustment, and transmits the two commands to the target inverter box so that the target inverter box can adjust the operating frequency and phase angle according to the two commands to achieve vehicle power matching.

[0094] In one possible implementation, the collaborative control module is also used to verify the imaginary part of the target inverter box output impedance in real time, wherein the target inverter box output impedance is the primary-side equivalent impedance of the dual LCC resonant converter.

[0095] In one possible implementation, the frequency of the square wave signal transmitted by the vehicle-mounted terminal corresponds to the power level of the corresponding vehicle.

[0096] In one possible implementation, the power supply cabinet also includes a modeling module for modeling the output power and output impedance of the inverter box.

[0097] It should be noted that the specific implementation of the EVDWPT system in this embodiment can be found in the above-described specific implementation of the EVDWPT ground control box group power synchronization method based on fiber optic synchronous frequency modulation. To avoid redundancy, it will not be repeated here.

[0098] In summary, this invention proposes and implements a dual-objective optimization problem for segmented rail charging in dynamic wireless charging by coordinating the adjustment of the operating frequency f and the phase shift angle β. This precisely matches the varying onboard power requirements and ensures inverter soft-start to minimize losses. Simulation verification also demonstrates the feasibility of this method.

[0099] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0100] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0101] Finally, it should be noted that the above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention should be considered equivalent substitutions and are included within the protection scope of the present invention.

Claims

1. A power synchronization method for EVDWPT ground control box groups based on fiber optic synchronous frequency modulation, applied to EVDWPT systems, characterized in that, The system includes a vehicle-mounted terminal and a ground power supply module. The vehicle-mounted terminal includes a receiving coil and a signal transmitter. The ground power supply module includes a power cabinet connected in parallel with the power grid and multiple segmented inverter boxes controlled by the power cabinet. Each inverter box is connected to a corresponding transmitting coil. The method includes: The vehicle-mounted unit sends a square wave signal containing the power level to the power cabinet via a signal transmitter; The power cabinet analyzes and identifies the power level in the square wave signal, generates a coordinated control signal containing a synchronization pulse frequency fine-tuning command and a phase shift angle adjustment command, obtains the current guide rail position of the vehicle emitting the square wave signal, and sends the coordinated control signal to the inverter box corresponding to the guide rail position. The inverter box receives the coordinated control signal and adjusts the operating frequency to the target frequency according to the synchronization pulse frequency fine-tuning command, and synchronously adjusts the phase difference between the fundamental wave of the output voltage and the current according to the phase shift angle adjustment command. The inverter box drives the corresponding transmitting coil according to the adjusted target frequency and phase shift angle to output power to the vehicle-mounted receiving coil that matches the power level, so as to meet the vehicle power matching requirements.

2. The method as described in claim 1, characterized in that, The power cabinet is equipped with a clock signal source, and the method further includes: the clock signal source transmitting a unified clock signal to multiple segmented inverter boxes via optical fiber.

3. The method as described in claim 1, characterized in that, The inverter box is equipped with a full-bridge inverter and a primary-side compensation network. The vehicle-mounted terminal also includes a secondary-side compensation network and a full-bridge rectifier. The inverter box, the corresponding transmitting coil, and the vehicle-mounted terminal form a dual LCC resonant converter. The method further includes soft-switching state verification, which includes: The imaginary part of the primary-side equivalent impedance of the dual LCC resonant converter is determined based on the adjusted target frequency. Determine whether the imaginary part of the primary-side equivalent impedance is greater than zero; If the value is greater than zero, the phase shift angle is maintained to enable soft start of the inverter; otherwise, the process returns to the step of regenerating the phase shift angle adjustment command.

4. The method as described in claim 1, characterized in that, Vehicles of different power levels send square wave signals of different frequencies through corresponding on-board terminals.

5. The method as described in claim 3, characterized in that, The output power modeling process of the inverter box includes: Based on Kirchhoff's voltage law, the voltage equations for each loop of the primary and secondary sides are derived from the dual-LCC equivalent circuit of the dual-LCC resonant converter. The output current of the dual LCC resonant converter is determined based on each voltage equation. The output power of the dual LCC resonant converter is determined based on the output current and the equivalent impedance of the load, and a three-dimensional mapping relationship between the output power, operating frequency, and phase shift angle is established, wherein the output power is used to characterize the output power of the inverter box.

6. The method as described in claim 3, characterized in that, The primary-side equivalent impedance modeling process includes: Determine the secondary-side equivalent impedance and reflection impedance of the dual LCC resonant converter; The primary side equivalent impedance is determined based on the secondary side equivalent impedance and the reflection impedance, so as to obtain the mapping relationship between the primary side equivalent impedance and the operating frequency.

7. An EVDWPT system, characterized in that, include: The vehicle-mounted unit includes a receiving coil and a signal transmitter that transmits square wave signals to the power supply cabinet. The ground power supply module includes a power cabinet connected in parallel with the power grid and multiple segmented inverter boxes controlled by the power cabinet, each inverter box being connected to a corresponding transmitting coil; wherein, the power cabinet includes: A clock signal source is used to transmit a unified clock signal to multiple segmented inverter boxes via optical fiber. The collaborative control module receives square wave signals, analyzes the power level, generates commands including synchronization pulse frequency fine-tuning and phase angle adjustment, and transmits the two commands to the target inverter box so that the target inverter box can adjust the operating frequency and phase angle according to the two commands to achieve vehicle power matching.

8. The system as described in claim 7, characterized in that, The collaborative control module is also used to verify the imaginary part of the output impedance of the target inverter box in real time, wherein the output impedance of the target inverter box is the primary side equivalent impedance of the dual LCC resonant converter.

9. The system as described in claim 7, characterized in that, The frequency of the square wave signal transmitted by the vehicle-mounted terminal corresponds to the power level of the corresponding vehicle.

10. The system as described in claim 7, characterized in that, The power cabinet also includes a modeling module for modeling the output power and output impedance of the inverter box.

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