Road pre-embedded type electric vehicle charging system

Abstract

The invention discloses a road pre-embedded type electric vehicle charging system. The invention relates to the technical field of wireless power transmission, and aims to solve the problem that an existing wireless charging technology based on a single physical coupling mechanism is difficult to maintain efficient and stable energy transmission. The system comprises a transmitting circuit module buried in a road and a receiving circuit module arranged at the bottom of a vehicle. The transmitting circuit module converts direct current into high-frequency alternating current, and a magnetic field and an electric field are generated to be mixed and coupled through a resonance compensation module comprising an induction coil, a compensation capacitor and a metal pole plate; the receiving circuit module receives energy through the matching resonance compensation module and transmits the energy to a load. The system introduces a space-time symmetry theory, and can maintain constant transmission efficiency and power in a dynamic scene that a transmission distance is smaller than a critical value when a specific critical condition is satisfied.

Description

A road-embedded electric vehicle charging system Technical Field

[0001] This invention relates to the field of wireless power transmission technology, and more particularly to a road-embedded electric vehicle charging system. Background Technology

[0002] During electric vehicle charging, static charging requires vehicles to be parked at fixed charging facilities, which cannot meet the energy replenishment needs during long-distance travel. Traditional dynamic wireless charging systems mostly employ single magnetic field coupling or electric field coupling, which have significant technical drawbacks. Single magnetic field coupling systems rely on the mutual inductance between coils to transfer energy. When the vehicle deviates laterally or the transmission distance changes during travel, the mutual inductance coefficient fluctuates significantly, leading to a sharp drop in transmission efficiency and output power. Furthermore, the strong magnetic field can easily cause electromagnetic interference to surrounding electronic equipment. Single electric field coupling systems transfer energy through the coupling capacitance between plates. While offering better electromagnetic compatibility, the coupling strength is weak, limiting transmission power and making it difficult to meet the high-power charging demands of electric vehicles. In addition, existing wireless charging systems generally lack stable transmission mechanisms, failing to maintain constant energy transmission performance under dynamic vehicle conditions. Therefore, it is necessary to propose a road-embedded electric vehicle charging system to address these problems. Summary of the Invention

[0003] The purpose of this invention is to provide a road-embedded electric vehicle charging system to solve the problem that existing wireless charging technologies based on a single physical coupling mechanism cannot maintain efficient and stable energy transmission.

[0004] This invention provides a road-embedded electric vehicle charging system, comprising: a road-side unit and a vehicle-side unit; the road-side unit is a transmitting circuit module embedded in the road structure, and the vehicle-side unit is a receiving circuit module installed on the bottom of the electric vehicle; the transmitting circuit module integrates a signal source module, a drive control module, a power inverter module, a power processing module, and a transmitting end resonant coupling module; the transmitting end resonant coupling module is connected to the output terminal of the power inverter module and includes a first induction coil, a first compensation capacitor, and a first metal plate to form a resonant circuit that simultaneously excites a magnetic field and an electric field; the receiving circuit module integrates a receiving end resonant coupling module and a power conversion module; the receiving end resonant coupling module includes a second induction coil, an adjustable compensation capacitor, and a second metal plate to form a receiving resonant circuit with the same frequency as the transmitting end resonant coupling module; the energy transmission of the system is based on a hybrid coupling mechanism of magnetic and electric fields, wherein magnetic field coupling is achieved through the mutual inductance between the first and second induction coils, and electric field coupling is achieved through the coupling capacitor formed between the first and second metal plates; the system is adjusted to make its electric field coupling coefficient k CCoupling coefficient k with magnetic field L The sum satisfies the following condition, thus operating in a parity-time symmetric state: ; where k C Let k be the electric field coupling coefficient. L γ is the magnetic field coupling coefficient, γ2 is the attenuation coefficient caused by the receiver loop resistance, and γ L ω0 is the attenuation coefficient caused by the load, and ω0 is the resonant frequency. When the transmission distance between the transmitting end resonant coupling module and the receiving end resonant coupling module is less than a critical value, the energy transmission efficiency and output power of the system remain constant.

[0005] Furthermore, the signal source module is configured to generate two pulse width modulation signals that are complementary in timing; the drive control module is connected to the signal source module and is used to receive the pulse width modulation signals and generate corresponding drive control signals. The drive control signals have preset dead time intervals, and the drive control module integrates a bootstrap circuit; the power inverter module is a full-bridge inverter topology, which consists of four switching transistors. The control terminal of the power inverter module is connected to the drive control module through a protection circuit including current-limiting resistors and voltage clamping devices. Its power terminal is connected between the DC power supply and the transmitting resonant coupling module, and is used to convert DC power into high-frequency AC power under the action of the drive control signal; the power processing module is used to provide filtered power to the drive control module and the power inverter module; the adjustable compensation capacitor is configured to adjust its capacitance value according to the coupling state; the input terminal of the power conversion module is connected to the output terminal of the receiving resonant coupling module, and is used to process the received energy and supply it to the load.

[0006] Furthermore, the drive control module includes a first drive submodule and a second drive submodule. The first drive submodule controls two diagonally opposite switches in the first group of the full-bridge inverter topology, and the second drive submodule controls two diagonally opposite switches in the second group of the full-bridge inverter topology. The two groups of switches are alternately turned on under the control of the complementary pulse width modulation signal.

[0007] Furthermore, the protection circuit includes a current-limiting resistor and a voltage clamping diode disposed on each switching transistor control path, as well as a filter capacitor and a freewheeling diode disposed on the power input terminal of the drive control module.

[0008] Furthermore, the power processing module includes a first set of filter capacitors connected in parallel to the DC power input terminal, a second set of filter capacitors connected in parallel to the drive power input terminal, and a third set of filter capacitors connected in parallel to the control power input terminal.

[0009] Furthermore, the adjustable compensation capacitor in the receiving end resonant coupling module is configured to adjust its value according to the real-time detected electric field coupling coefficient and magnetic field coupling coefficient to maintain the parity-time symmetry state.

[0010] Furthermore, the power conversion module includes a rectifier bridge, a DC filter circuit, and a DC-DC converter in sequence, and the output terminal of the DC-DC converter is used to connect to the power battery of the electric vehicle.

[0011] Furthermore, the signal source module uses a direct digital frequency synthesizer chip or a microcontroller to generate the complementary pulse width modulation signal.

[0012] The beneficial effects of this invention are as follows: The road-embedded electric vehicle charging system of this invention, by introducing parity-time symmetry theory, allows the system to maintain constant transmission efficiency and output power under dynamic conditions where the sum of the electric field coupling coefficient and the magnetic field coupling coefficient meets the critical condition, effectively solving the problem of transmission performance fluctuations caused by vehicle position deviation during driving. This invention employs a hybrid magnetic and electric field coupling method, combining the advantages of high transmission power from magnetic field coupling and good electromagnetic compatibility from electric field coupling, meeting the high-power charging needs of electric vehicles while reducing interference to surrounding electronic equipment. Through clamping protection, current limiting modules, and power filtering modules, this invention effectively prevents the impact of overvoltage, overcurrent, and high-frequency noise on the system, improving the system's reliability in complex highway environments. The deployment method of embedding the transmitting module in the road and installing the receiving module on the bottom of the vehicle enables dynamic wireless charging of electric vehicles during driving, greatly improving the range and ease of use of electric vehicles. Attached Figure Description

[0013] To more clearly illustrate the technical solution of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, those skilled in the art can obtain other drawings based on these drawings without creative effort.

[0014] Figure 1 is a schematic diagram of the overall structure of the present invention; Figure 2 is an equivalent circuit diagram of the present invention; Figure 3 is a block diagram of the circuit flow of the present invention; Figure 4 is a structural diagram of the power switching module and clamping protection and current limiting module of the full-bridge inverter of the present invention; Figure 5 is a structural diagram of the signal source module of the present invention; Figure 6 is a structural diagram of the drive signal module of the present invention; Figure 7 is a structural diagram of the power supply filtering module of the present invention; Figure 8 is a structural diagram of the resonant compensation module of the receiver and transmitter of the present invention; Figure 9 is an amplitude analysis diagram of the system of the present invention at a transmission distance d=1m; Figure 10 is an amplitude analysis diagram of the system of the present invention at a transmission distance d=1.8m; Figure 11 is an analysis diagram of the operating frequency of the system of the present invention as a function of transmission distance; Figure 12 is an analysis diagram of the output power of the system of the present invention as a function of transmission distance. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention. The technical solutions provided by various embodiments of this invention will be described in detail below with reference to the accompanying drawings.

[0016] Please refer to Figures 1 to 12. This embodiment of the invention provides a road-embedded electric vehicle charging system, which includes a road-side unit and a vehicle-side unit. The road-side unit is a transmitting circuit module embedded within the road structure, and the vehicle-side unit is a receiving circuit module installed on the bottom of the electric vehicle. The transmitting circuit module's pre-embedding in the road allows for concealed deployment without occupying ground space, while the receiving circuit module's integration into the vehicle chassis meets the installation requirements of onboard equipment, providing a foundation for energy capture during vehicle operation.

[0017] The transmitting circuit module integrates a signal source module, a drive control module, a power inverter module, a power processing module, and a transmitter resonant coupling module. This integrated design concentrates the core functions of energy conversion and control on the roadside, facilitating centralized power supply, maintenance, and management. The signal source module is configured to generate two timing-complementary pulse-width modulation (PWM) signals. Its function is to generate the system's initial control timing; the two complementary signals are the foundation for driving the subsequent full-bridge inverter circuit to operate correctly, ensuring the synchronization and accuracy of energy conversion. The drive control module connects to the signal source module and receives the PWM signals to generate corresponding drive control signals. The drive control signals have preset dead-time intervals, and the drive control module integrates a bootstrap circuit. The core function of the drive control module is to amplify weak logic signals to a level sufficient to reliably drive the power switches. The preset dead-time effectively prevents shoot-through short circuits caused by asynchronous switching between the upper and lower switches on the same bridge arm, which is crucial for ensuring system safety. The integrated bootstrap circuit provides a simple floating power supply solution for driving the high-side switches, simplifying circuit design and improving reliability. The power inverter module is a full-bridge inverter topology, consisting of four switching transistors. Its control terminal is connected to the drive control module via a protection circuit including current-limiting resistors and voltage clamping devices. Its power terminal is connected between the DC power supply and the transmitter resonant coupling module, converting DC power into high-frequency AC power under the influence of the drive control signal. The full-bridge inverter topology is a mature and efficient solution for high-power DC-to-AC conversion. The current-limiting resistors in the protection circuit suppress peak current in the drive circuit, protecting the drive chip and the gates of the switching transistors; voltage clamping devices, such as Zener diodes or diodes, limit the gate voltage within a safe range, preventing overvoltage breakdown. The module ultimately outputs high-frequency AC power, providing the necessary alternating field source for wireless power transmission. The power processing module provides filtered power to the drive control module and the power inverter module. Its advantages include suppressing high-frequency noise and ripple from the mains or DC power supply, providing a clean and stable operating voltage for sensitive drive and power circuits, preventing signal distortion or malfunctions caused by power supply interference, and improving the stability and reliability of the entire system.

[0018] The transmitting resonant coupling module is connected to the output of the power inverter module. It includes a first induction coil, a first compensation capacitor, and a first metal plate to form a resonant circuit that simultaneously excites magnetic and electric fields. This is the core of the system's energy transmission. A high-frequency current is passed through the first induction coil to generate an alternating magnetic field, while a high-frequency voltage is applied to the first metal plate to generate an alternating electric field. The first compensation capacitor, together with the coil inductance, forms an LC resonant circuit, allowing the system to operate at its resonant frequency and maximizing energy transmission. This design achieves hybrid coupling transmission of magnetic and electric fields, combining the advantages of both coupling methods. The receiving circuit module integrates the receiving resonant coupling module and the power conversion module. This integrated design facilitates functionality within the limited space at the bottom of the vehicle and reduces connection losses. The receiving resonant coupling module includes a second induction coil, an adjustable compensation capacitor, and a second metal plate to form a receiving resonant circuit with the same frequency as the transmitting resonant coupling module. The adjustable compensation capacitor is configured to adjust its value according to the coupling state. The second induction coil and the second metal plate are used to receive magnetic and electric field energy, respectively. The adjustable compensation capacitor plays a crucial role. It can dynamically compensate for changes in coupling parameters caused by vehicle movement, ensuring that the receiving circuit always resonates with the transmitting frequency and achieves impedance matching, thereby maintaining the highest energy receiving efficiency. This is one of the key technologies for achieving stable and efficient dynamic charging.

[0019] The input of the power conversion module is connected to the output of the receiving resonant coupling module, used to process the received energy and supply it to the load. Its function is to process the received AC power and convert it into DC power suitable for charging the electric vehicle's battery. This typically includes rectification, filtering, and voltage conversion steps, serving as a bridge between the wireless receiving system and the vehicle battery. The system's energy transmission is based on a hybrid coupling mechanism of magnetic and electric fields. Magnetic field coupling is achieved through the mutual inductance between the first and second induction coils, while electric field coupling is achieved through the coupling capacitance formed between the first and second metal plates. The advantage of this hybrid coupling mechanism is that it combines the advantages of both single coupling modes: magnetic field coupling is beneficial for transmitting high power, while electric field coupling offers better electromagnetic compatibility, and the two can complement each other. When one coupling weakens due to distance or offset, the other coupling can still maintain a certain transmission capacity, thereby enhancing the system's robustness and transmission distance under dynamic operating conditions.

[0020] The system is tuned to make its electric field coupling coefficient k C Coupling coefficient k with magnetic field L The sum satisfies the following condition, thus operating in a parity-time symmetric state: ; where k C Let k be the electric field coupling coefficient. L γ is the magnetic field coupling coefficient, γ2 is the attenuation coefficient caused by the receiver loop resistance, and γ LLet ω0 be the attenuation coefficient caused by the load, and ω0 be the resonant frequency. This is the core control theory of this system. By satisfying this critical condition, the system can operate in an unbroken parity-time symmetric state. The key advantage is that when the transmission distance is less than a critical value, the system's energy transmission efficiency and output power remain constant. This means that within a certain driving range, the charging power and efficiency will not fluctuate drastically with small changes in the distance between the vehicle and the road-based transmitting module, thus achieving stable output during dynamic charging and solving the key problem of unstable performance in traditional wireless charging systems under dynamic conditions.

[0021] The innovation of this invention lies in two aspects. First, it creatively integrates magnetic field coupling and electric field coupling mechanisms into a road-embedded charging system, combining the advantages of high-power transmission and good electromagnetic compatibility. Second, it applies parity-time symmetry theory to the regulation of this hybrid coupling system, setting explicit critical conditions for the coupling coefficient, enabling the system to maintain constant efficiency and power under dynamic operating conditions, greatly improving charging stability. Finally, the entire system solution is complete, from integrated transmission on the roadside to intelligent reception on the vehicle side, forming an engineering-deployable dynamic wireless charging solution for electric vehicles, possessing significant practical value and application prospects. The following provides a detailed description of this solution.

[0022] 1. System Overall Structure: Transmitter Circuit Module: This module converts DC power into high-frequency AC power and simultaneously generates magnetic and electric field coupling through a resonant coupling network. It includes a full-bridge inverter power switch module, a drive signal module, a clamping protection and current limiting module, a power filter module, a signal source module, and a transmitter resonant compensation module. The connections between these components are as follows: The power filter module is electrically connected to both the drive signal module and the full-bridge inverter power switch module, providing them with stable filtered power; the output of the signal source module is electrically connected to the input of the drive signal module, providing it with an initial control signal; the output of the drive signal module is electrically connected to the input of the clamping protection and current limiting module, and the generated drive signal is output after protection processing; the output of the clamping protection and current limiting module is electrically connected to the input of the full-bridge inverter power switch module, controlling the on / off state of the power switch; and the output of the full-bridge inverter power switch module is electrically connected to the input of the transmitter resonant compensation module, converting DC power into high-frequency AC power and inputting it into the resonant network.

[0023] Receiver circuit module: Used to simultaneously receive energy from magnetic field coupling and electric field coupling through a resonant coupling network and transfer it to the load. It includes a receiver resonant compensation module and a load circuit. The output of the receiver resonant compensation module is electrically connected to the input of the load circuit, and the received energy is conditioned before being supplied to the load.

[0024] 2. Core Module Structure: Transmitter Resonance Compensation Module: This module comprises an induction coil, a compensation capacitor, and metal plates, which are integrated to form an inductor-capacitor resonant circuit with a resonant frequency of ω0. The induction coil provides a magnetic field coupling path, the metal plates provide an electric field coupling path, and the compensation capacitor adjusts the circuit's resonant frequency to ensure the system operates at a preset frequency.

[0025] The receiver-side resonant compensation module includes an induction coil, an adjustable compensation capacitor, and metal plates, forming an inductor-capacitor resonant circuit with the same resonant frequency as the transmitter. The adjustable compensation capacitor can adjust its capacitance in real time according to the system coupling state to maintain parity-time symmetry or achieve impedance matching, ensuring efficient energy reception.

[0026] The full-bridge inverter power switching module consists of an H-bridge structure formed by four switching transistors. The control terminals of the transistors are connected to the output terminals of the drive signal module through current-limiting resistors, while the power terminals are connected between the DC power supply and the transmitter resonant compensation module. By alternating the conduction of the switching transistors, the input DC power is converted into high-frequency AC power, providing energy for the resonant coupling network.

[0027] Drive signal module: Includes two drive modules, each controlling the alternating conduction of a set of diagonal switches in the H-bridge. The drive module has a built-in bootstrap circuit to maintain a stable high-side drive voltage, and a dead time of 200ns-1μs is set in the drive signal to prevent two switches in the same bridge arm from conducting simultaneously and causing a short circuit.

[0028] Clamping protection and current limiting module: Current limiting resistors and voltage clamping devices are set on the control path of each switching transistor to suppress overcurrent and overvoltage; filtering and freewheeling components are set at the power supply end of the drive module to ensure the stability of the drive power supply and provide reliable protection for the power switching module.

[0029] Power supply filtering module: includes multiple high-frequency filter capacitors, which are connected in parallel to the DC power input terminal, the drive power input terminal and the control power input terminal, respectively, to suppress high-frequency noise and ripple and improve power quality.

[0030] Signal source module: configured to generate two complementary pulse width modulation signals, which are output to the corresponding input terminals of the drive signal module respectively. By controlling the timing of the drive signals, the power switching module of the full-bridge inverter can be switched in an orderly manner.

[0031] 3. Parity-Time Symmetric Working Mechanism: The system is configured to operate in a parity-time symmetric state, the core of which is to make the system's electric field coupling coefficient k... C Coupling coefficient k with magnetic field L The sum satisfies a preset critical condition. When the transmission distance d is less than the critical distance dcr, this condition ensures that the system's transmission efficiency and output power remain constant. The critical condition for the parity-time symmetric state is: ; where, k C is the electric field coupling coefficient, k L is the magnetic field coupling coefficient, γ2 is the attenuation coefficient caused by the resistance of the receiving-end loop, γ L is the attenuation coefficient caused by the load, and ω0 is the resonant frequency.

[0032] 4. Coupling method The energy transfer between the transmitting end and the receiving end is achieved through hybrid coupling: the induction coils in the transmitting-end resonant compensation module and the induction coils in the receiving-end resonant compensation module achieve magnetic field coupling through the mutual inductance effect; a coupling capacitor is formed through electric field induction between the metal plates in the transmitting-end resonant compensation module and the metal plates in the receiving-end resonant compensation module to achieve electric field coupling. The two coupling methods work together to improve the coupling strength and anti-interference ability of the system.

[0033] 5. System deployment method The transmitting circuit module is suitable for being buried inside the road, and the receiving circuit module is suitable for being installed at the bottom of the electric vehicle. When the vehicle is driving on the road equipped with this system, the receiving module and the transmitting module perform energy transfer in real time through hybrid coupling. Combining with the parity-time symmetry mechanism, a stable energy transfer efficiency and output power are maintained during the dynamic driving process of the vehicle.

[0034] 1) Describing the dynamic behavior of the system Case 1, unbroken PT symmetry state: .

[0035] Case 2, broken PT symmetry state: ) .

[0036] In Case 1, the efficiency (90%) and output power (9.2 kW) remain constant when d < dcr.

[0037] In Case 2, the efficiency decreases with the distance, but the dual-coupling system is still better than the single-coupling system, and the efficiency still reaches 83% when d = 2 m.

[0038] 2) Amplitude analysis According to the formula and the current and voltage data simulated by PSIM, the curve of An can be obtained, as shown in Figures 9 and 10. Here, the gray solid line represents mode A1, and the red solid line represents mode A2. When d = 1 m and the system is under the conditions of Case 1, when the system reaches the stable state, the amplitudes of A1 and A2 are almost equal. When d = 1.8 m and the system is under the conditions of Case 2, the two amplitudes are no longer the same, and A2 is much smaller than A1.

[0039] 3) The working frequency analysis is shown by the blue solid line in Fig. 11. When d < dcr, a bifurcation can be observed and the value of the working frequency switches between two branches. For example, when d is 0.2 m or 0.4 m, the simulation results are consistent with the high-frequency branch, and when d is 0.6 m or 0.8 m, the simulation results are consistent with the low-frequency branch. When d > dcr, the bifurcation disappears and the working frequency is ω0.

[0040] 4) The output power analysis results show that when d < dcr, the system provides about 9 kW of power to the load, while the theoretical value is 9.2 kW. Similarly, when d > dcr, an increase in the output power can be observed. The simulation results are in exact agreement with the theoretical analysis.

[0041] In summary, a key feature of this system is its ability to operate in a PT-symmetric state. As shown in Figs. 10 to 12, when the transmission distance d is less than the critical distance dcr, the system satisfies the conditions, and at this time the system is in an unbroken PT-symmetric state. In this state, the transmission efficiency and output power of the system can remain constant. Simulations and theoretical calculations show that the efficiency can be stabilized above 90%, and the output power can reach 9.2 kW. When the distance d exceeds dcr, the system enters a broken PT-symmetric state and the efficiency begins to decline. However, due to the synergistic effect of double coupling, the rate of efficiency decay is much lower than that of a single magnetic coupling or electrical coupling system.

[0042] Among them, "PT symmetry" means that after a system jointly performs a parity operation (P) and a time-reversal operation (T), the Hamiltonian describing the system remains unchanged.

[0043] The MOSFET component, whose full name is (Metal-Oxide-Semiconductor Field-Effect Transistor) metal-oxide semiconductor field-effect transistor, acts as a power switching device in this full-bridge inverter and cooperates with other MOSFET components to achieve the conversion from DC to high-frequency AC.

[0044] PWM is the English abbreviation of "Pulse Width Modulation". It is a modulation technique that controls the output of a circuit by adjusting the ratio of the "on time (high-level duration)" to the "entire cycle duration" (i.e., the "duty cycle") in a periodic pulse signal.

[0045] In this full-bridge inverter, the core role of the PWM drive signal is to precisely control the on / off timing of the MOSFET, which can not only achieve the conversion from DC to high-frequency AC but also flexibly adjust the equivalent amplitude of the output voltage by adjusting the duty cycle.

[0046] Specific embodiments are provided below. These embodiments are intended to enable those skilled in the art to more fully understand the present invention, but do not limit the present invention in any way.

[0047] Example: I. Overall System Deployment In this example, the wireless charging highway system with hybrid magnetic and electric field coupling mainly consists of a transmitting circuit module buried beneath the highway surface and a receiving circuit module installed on the chassis of the electric vehicle. The transmitting circuit module is arranged in segments along the highway lanes, each segment being 50 meters long. Adjacent segments are seamlessly switched by the control system to ensure a continuous energy supply during vehicle operation. The receiving circuit module is fixed at the center of the bottom of the electric vehicle, with its induction coil and metal plate aligned with the corresponding components of the transmitting module beneath the highway to ensure effective coupling.

[0048] II. Specific Implementation of Core Modules 1. Transmitter Circuit Module: As shown in Figure 5, the signal source module uses an AD9850 DDS signal generator as signal sources XFG1 and XFG2 to generate two complementary PWM signals with a frequency of 100kHz and a duty cycle of 50%. Specifically, the P1 pin of XFG1 outputs a signal to the LIN terminal of driver module U2, and the P2 pin outputs a signal to the HIN terminal of U2; the P3 pin of XFG2 outputs a signal to the LIN terminal of driver module U1, and the P4 pin outputs a signal to the HIN terminal of U1.

[0049] As shown in Figure 6, the drive signal module uses IR2110 as the drive chips U1 and U2, which have a built-in bootstrap circuit. The VDD pin of U1 and U2 is connected to a 5V power supply VDD1, and the VCC pin is connected to a 12V power supply VCC1. The VSS, COM, and SD pins are grounded. The HO pin of U1 is connected to the gate of the switching transistor Q1 through a current-limiting resistor R6, and the LO pin is connected to the gate of Q2 through a current-limiting resistor R8. The HO pin of U2 is connected to the gate of Q4 through a current-limiting resistor R1, and the LO pin is connected to the gate of Q3 through a current-limiting resistor R3. A bootstrap capacitor C4 (1μF) is connected to the VB and VS pins of U1 and U2 respectively to maintain a stable high-side drive voltage. The dead time of the drive signal is set to 500ns through external circuitry to prevent short circuits in the bridge arms.

[0050] As shown in Figure 4, the clamping protection and current limiting module consists of a 1N4148 clamping diode and a 10Ω current limiting resistor on the gate path of each switching transistor. Specifically, the anode of diode D4 at the gate of Q1 is connected to the gate of Q1, and the cathode is connected to the HO terminal of U1 and parallel to R6; the anode of diode D6 at the gate of Q2 is connected to the gate of Q2, and the cathode is connected to the LO terminal of U1 and parallel to R8; the anode of diode D3 at the gate of Q3 is connected to the gate of Q3, and the cathode is connected to the LO terminal of U2 and parallel to R3; the anode of diode D2 at the gate of Q4 is connected to the gate of Q4, and the cathode is connected to the HO terminal of U2 and parallel to R1. At the power supply terminal of the driver chip, VCC1 is grounded via filter capacitor C8 (100nF) and then connected to the anode of freewheeling diode D1, with the cathode of D1 connected to the HO terminal of U2; similarly, VCC1 is grounded via C3 (100nF) and then connected to the anode of D5, with the cathode of D5 connected to the HO terminal of U1, thus achieving power filtering and freewheeling protection.

[0051] As shown in Figure 4, the full-bridge inverter power switching module uses IRF540N MOSFETs as switching transistors Q1-Q4, forming an H-bridge structure. The drains of Q1 and Q4 are connected to the positive terminal of the DC power supply VEE1 (48V). The source of Q1 and the drain of Q2 are connected together to form the first bridge arm output node V1_out, and the source of Q4 and the drain of Q3 are connected together to form the second bridge arm output node V2_out. The sources of Q2 and Q3 are connected to the negative terminal of VEE1 and grounded. Through the complementary drive signals output by U1 and U2, the alternating operating mode of simultaneous conduction of Q1 and Q3 and simultaneous conduction of Q2 and Q4 is controlled, converting the 48V DC power into 100kHz high-frequency AC power, which is output from V1_out and V2_out to the transmitter resonant compensation module.

[0052] As shown in Figure 7, the power supply filtering module consists of a 10μF electrolytic capacitor and a 100nF ceramic capacitor C5 connected in parallel at the VDD1 (12V) input terminal, a 4.7μF electrolytic capacitor and a 100nF ceramic capacitor C6 connected in parallel at the VCC1 (5V) input terminal, and a 100μF electrolytic capacitor and a 100nF ceramic capacitor C7 connected in parallel at the VEE1 (48V) input terminal. The combination of capacitors with different capacitance values ​​suppresses high-frequency ripple and noise, providing a stable power supply for each module.

[0053] As shown in Figure 8, the transmitter resonant compensation module consists of: an induction coil L1 wound with 1mm diameter enameled wire, 20 turns, and an inductance of 30μH; a compensation capacitor C1 is a 100pF high-frequency capacitor, forming an LC resonant circuit with L1, with a resonant frequency ω0 = 2π × 100kHz. The metal plate is an aluminum plate with an area of ​​0.5m × 0.5m, and the distance between it and the receiver plate is maintained at 10-20cm. V1_out and V2_out are connected to one end of the equivalent impedance Rc (obtained by the equivalent of resistor R5 and inductor L3). The other end of Rc is connected to one end of L1. The other end of L1 is split into two paths: one connected to C1, and the other connected to the equivalent capacitance Cs of the metal plate.

[0054] 2. The receiving circuit module is shown in Figure 8. The receiving end resonance compensation module: the parameters of the induction coil L2 are the same as L1 (inductance value 30μH). The compensation capacitor C2 is an adjustable capacitor (capacitance range 50-150pF). The circuit voltage is detected in real time by a voltage sensor, and the capacitance value of C2 is dynamically adjusted to maintain the same resonant frequency as the transmitting end. The metal plate has the same size as the transmitting end plate to ensure the stability of the coupling capacitor. One end of L2 is connected to C2 and the equivalent capacitance Cs of the metal plate, and the other end is connected to the equivalent resistance R10 formed by the receiving end resistor Rd (10Ω) and the load resistor RL (equivalent resistance of the electric vehicle power battery, adjustable from 10-50Ω) in series. The other end of R10 is grounded.

[0055] Load circuit: Includes a rectifier bridge, filter capacitors, and a DC-DC converter. The high-frequency AC power output from the receiver resonant compensation module is rectified into DC power by the rectifier bridge (model KBPC3510), then filtered by a 100μF filter capacitor, and finally input to the DC-DC converter (output voltage 300-400V, adapted to the power battery voltage), ultimately supplying stable DC power to the electric vehicle's power battery.

[0056] 3. Before the parity-time symmetric state control system is put into operation, the critical condition parameters are determined through simulation calculations: resonant frequency ω0 = 2π × 100kHz ≈ 6.28 × 10 5 rad / s, attenuation coefficient γ2 caused by receiver loop resistance = 0.5 × 10 3 rad / s, load-induced attenuation coefficient γ L =1×10 3 rad / s.

[0057] Substitute these parameters into the critical condition formula to calculate:

[0058] The calculation results show that in order for the system to operate in a PT-symmetric state, the sum of the magnetic field coupling coefficient and the electric field coupling coefficient must be greater than 0.00478.

[0059] During vehicle operation, the system collects K data in real time through the coupling coefficient detection module. L and K C When the vehicle and the road-based transmitter module are properly aligned, the magnetic field coupling coefficient K is collected. L ≈0.15, electric field coupling coefficient K C ≈0.12. The sum of the two (0.27) is much greater than the critical condition (0.00478), ensuring that the system operates stably in a PT-symmetric state. At this point, the transmission efficiency can be maintained above 90%, and the output power is stable at 10kW. When the vehicle experiences a slight deviation, causing the magnetic field coupling coefficient K to... L When the voltage drops to 0.12, the control system will actively reduce the electric field coupling coefficient by adjusting the spacing between the metal plates at the receiving end (achieved by a mechanical adjustment mechanism). The coefficient is increased to 0.15, thus ensuring that the total coupling coefficient is restored to the optimal level (0.12 + 0.15 = 0.27), always meeting the critical condition and maintaining stable transmission performance. This active control mechanism ensures that the system can maintain efficient and constant energy transmission even under dynamic changes.

[0060] III. System Workflow 1. Start-up Phase: The highway-side transmitting circuit module is powered on, the power filtering module filters each power source and supplies power to the drive signal module and the full-bridge inverter power switch module; the signal source module starts up and generates a complementary PWM signal, which is output to the drive signal module.

[0061] 2. Drive and Inverter Stage: After receiving the PWM signal, the drive signal module processes it through the bootstrap circuit to generate a drive signal with a dead time. After being protected against overvoltage and overcurrent by the clamping protection and current limiting module, it is output to the full-bridge inverter power switch module to control the alternating conduction of Q1-Q4, converting DC power into high-frequency AC power.

[0062] 3. Coupling and Transmission Stage: The high-frequency AC input to the transmitter resonant compensation module, L1 generates a magnetic field and the metal plate generates an electric field, and the energy is transmitted to the receiver through a hybrid coupling method; the receiver resonant compensation module receives magnetic field energy through L2 and electric field energy through the plate, and outputs it to the load circuit after resonant conditioning.

[0063] 4. Stable regulation phase: The system monitors the electric field coupling coefficient, magnetic field coupling coefficient, transmission efficiency, and output power in real time. When the sum of the electric field coupling coefficient and magnetic field coupling coefficient approaches the critical value or the transmission performance fluctuates, the system adjusts the capacitance of the adjustable capacitor C2 at the receiving end and the plate spacing to maintain the PT symmetry state and ensure stable energy transmission.

[0064] 5. Stopping phase: After the vehicle leaves the current transmitter module section, the control system cuts off the power supply to the transmitter module in that section, and the transmitter module in the next section starts in advance to achieve seamless switching; after the vehicle completely leaves the charging road, all transmitter modules are in standby mode and the receiver modules stop working.

[0065] IV. Input and Output Waveform Analysis (Simulation and Actual Measurement Verification) To verify the rationality and operational stability of the system circuit design, this embodiment uses Multisim simulation software combined with oscilloscope measurements to analyze the system's input and output waveforms. The results are as follows: 4.1 Input Waveform Analysis The input waveform is a high-frequency AC signal output by the full-bridge inverter. Based on the simulation and actual measurement data, the key features and technical significance are analyzed as follows: 1) Core Waveform Features and Parameter Calculation Time base setting: 100μs / div (100μs per division on the X-axis), period occupies 2.5 divisions → period T = 2.5 × 100μs = 250μs → frequency f = 1 / T = 4kHz, which meets the resonant frequency requirements of the wireless charging system.

[0066] Voltage amplitude: Channel A range 500V / div (500V per division on the Y-axis), peak value occupies 0.2 divisions → Vpp=0.2×500V=100V; The measured voltage at point T1 is 118.846V, and the error between it and the calculated value is within ±5%, which meets the measurement accuracy requirements.

[0067] Duty cycle: High level time 1.25 divisions (125μs), duty cycle D=125μs / 250μs=50%, which is a typical characteristic of the bipolar modulation mode of the full-bridge inverter, ensuring the symmetrical and stable output waveform.

[0068] 2) Waveform quality and system status assessment: rise time <1μs, steep edges, indicating that high-frequency devices such as MOSFETs have good switching performance and the response speed meets the requirements of high-frequency inverter.

[0069] If the overshoot amplitude is less than 5% and there is no obvious ringing, it indicates that the circuit impedance is well matched, the parasitic parameters are reasonably controlled, and there is no significant parasitic oscillation.

[0070] Abnormal signal troubleshooting: The signal level is stable with no jitter, the edges are clean with no oscillation, and there is only a 0.4-division Y-axis baseline offset, which does not affect the normal operation of the system.

[0071] Circuit topology verification: The symmetrical square wave output is consistent with the theoretical waveform of the bipolar modulation of the full-bridge inverter, verifying the correctness of the topology design.

[0072] 4.2 Output Waveform Analysis The output waveform is the high-frequency AC signal before the load circuit input at the receiving end, reflecting the signal quality after energy transmission. The core analysis is as follows: 1) Core parameter verification of frequency characteristics: The time base is set to 50μs / div, and the complete period occupies 2 divisions → T=2×50μs=100μs → The actual frequency f=1 / T=10kHz, which matches the system resonant frequency, indicating that the frequency stability is good during the coupling transmission process.

[0073] Voltage characteristics: With the range set at 1kV / div, the measured trough value at point T1 is -1.708kV, and the peak value is approximately 0.292kV (affected by Y-axis displacement). The actual peak-to-peak value (Vpp) = 0.292kV (-1.708kV) = 2.0kV, which meets the voltage requirements for high-power charging of electric vehicles. Table 1 is the waveform quality assessment table.

[0074] Table 1 Waveform Quality Assessment Table

[0075] This embodiment achieves a wireless charging system with hybrid coupling of magnetic and electric fields through specific module selection, parameter design, and process optimization. Input and output waveform analysis verifies the rationality of the circuit topology, the adaptability of the selected components, and the stability of the system operation—the symmetrical square wave characteristics of the input waveform conform to the full-bridge modulation design, the high-frequency, high-voltage characteristics of the output waveform meet charging requirements, and the waveform quality indicators all meet industrial application standards. Combined with the control mechanism of PT symmetry theory, the system can maintain efficient and stable transmission under dynamic operating conditions, providing a reliable technical solution for dynamic wireless charging of electric vehicles.

[0076] The embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention.

Claims

1. A road-embedded electric vehicle charging system, characterized in that, include: The system comprises a road-side unit and a vehicle-side unit; the road-side unit is a transmitting circuit module embedded in the highway structure, and the vehicle-side unit is a receiving circuit module installed on the bottom of an electric vehicle; the transmitting circuit module integrates a signal source module, a drive control module, a power inverter module, a power processing module, and a transmitting end resonant coupling module; the transmitting end resonant coupling module is connected to the output terminal of the power inverter module and includes a first induction coil, a first compensation capacitor, and a first metal plate; the receiving circuit module integrates a receiving end resonant coupling module and a power conversion module; the receiving end resonant coupling module includes a second induction coil, an adjustable compensation capacitor, and a second metal plate; the energy transmission of the system is based on a hybrid coupling mechanism of magnetic and electric fields, wherein magnetic field coupling is achieved through the mutual inductance between the first and second induction coils, and electric field coupling is achieved through the coupling capacitor formed between the first and second metal plates; the system is controlled to make its electric field coupling coefficient k C Coupling coefficient k with magnetic field L The sum satisfies the following condition, thus operating in a parity-time symmetric state: ; where k C Let k be the electric field coupling coefficient. L γ is the magnetic field coupling coefficient, γ2 is the attenuation coefficient caused by the receiver loop resistance, and γ L ω0 is the attenuation coefficient caused by the load, and ω0 is the resonant frequency. When the transmission distance between the transmitting end resonant coupling module and the receiving end resonant coupling module is less than a critical value, the energy transmission efficiency and output power of the system remain constant.

2. The road-embedded electric vehicle charging system according to claim 1, characterized in that, The signal source module is configured to generate two pulse width modulation signals that are complementary in timing. The drive control module is connected to the signal source module and is used to receive the pulse width modulation signals and generate corresponding drive control signals. The drive control signals have preset dead time intervals. The drive control module integrates a bootstrap circuit. The power inverter module is a full-bridge inverter topology, consisting of four switching transistors. The control terminal of the power inverter module is connected to the drive control module through a protection circuit including current-limiting resistors and voltage clamping devices. Its power terminal is connected between the DC power supply and the transmitter resonant coupling module, and is used to convert DC power into high-frequency AC power under the action of the drive control signals. The power processing module is used to provide filtered power to the drive control module and the power inverter module. The adjustable compensation capacitor is configured to adjust its capacitance value according to the coupling state; the input terminal of the power conversion module is connected to the output terminal of the receiving resonant coupling module, and is used to process the received energy and supply it to the load.

3. The road-embedded electric vehicle charging system according to claim 2, characterized in that, The drive control module includes a first drive submodule and a second drive submodule. The first drive submodule controls two diagonally opposite switches in the first group of the full-bridge inverter topology, and the second drive submodule controls two diagonally opposite switches in the second group of the full-bridge inverter topology. The two groups of switches are alternately turned on under the control of the complementary pulse width modulation signal.

4. The road-embedded electric vehicle charging system according to claim 1, characterized in that, The protection circuit includes a current-limiting resistor and a voltage clamping diode disposed on each switching transistor control path, and a filter capacitor and a freewheeling diode disposed on the power input terminal of the drive control module.

5. A road-embedded electric vehicle charging system according to claim 1, characterized in that, The power processing module includes a first set of filter capacitors connected in parallel to the DC power input terminal, a second set of filter capacitors connected in parallel to the drive power input terminal, and a third set of filter capacitors connected in parallel to the control power input terminal.

6. A road-embedded electric vehicle charging system according to claim 1, characterized in that, The adjustable compensation capacitor in the receiving end resonant coupling module is configured to adjust its value according to the real-time detected electric field coupling coefficient and magnetic field coupling coefficient in order to maintain the parity-time symmetry state.

7. A road-embedded electric vehicle charging system according to claim 1, characterized in that, The power conversion module includes a rectifier bridge, a DC filter circuit, and a DC-DC converter in sequence. The output terminal of the DC-DC converter is used to connect to the power battery of the electric vehicle.

8. A road-embedded electric vehicle charging system according to claim 2, characterized in that, The signal source module uses a direct digital frequency synthesizer chip or a microcontroller to generate the complementary pulse width modulation signal.

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