A multi-agv wireless charging station leakage magnetic field cooperative cancellation control method and system

Abstract

The application discloses a kind of multi-AGV wireless charging work station inter magnetic flux leakage collaborative mutual cancellation control method and system.This application when at least two AGVs simultaneously carry out wireless charging in adjacent work station, the transmission controller of two work stations is connected by workshop communication network, exchange the geometric parameter of respective transmission coil and parking position information, calculate the optimal phase difference of minimum synthesis magnetic field amplitude in the public area between two work stations;Two controllers are with grid ac voltage zero-crossing point as synchronous reference, according to the optimal phase difference described, respectively control the output phase of respective inverter, so that the phase difference of excitation current of two transmission coils is locked at the optimal phase difference described, so that the magnetic field generated by two independent transmission systems is spatially reversed, realize the mutual cancellation of inter-work station public area magnetic flux leakage, so that it meets the requirement of electromagnetic safety standard.This application is applied to the technical field of wireless charging.

Description

Technical Field

[0001] This invention relates to the field of wireless charging technology, and specifically to a method and system for collaborative cancellation of magnetic leakage between multiple AGV wireless charging stations. This invention requires no additional shielding hardware; it achieves magnetic leakage suppression purely through cross-device collaborative control. It has a low modification threshold and is suitable for multi-station cluster charging scenarios in AGV workshops. Background Technology

[0002] Automated Guided Vehicles (AGVs) are widely used in smart manufacturing and warehousing logistics, and their charging methods are gradually transitioning from contact charging to wireless charging. In AGV workshops, multiple parallel wireless charging stations are typically arranged to allow multiple AGVs to simultaneously dock and recharge. When a high-power wireless charging system is operating, a strong spatial leakage magnetic field is generated between the transmitting and receiving coils. When multiple AGVs are charging simultaneously at adjacent stations, the leakage magnetic fields from each transmitting coil are superimposed in the passageway between stations, potentially causing the electromagnetic exposure intensity in that area to exceed relevant safety standard limits (such as ICNIRP guidelines), posing a potential electromagnetic safety risk to personnel passing through the passageway.

[0003] Currently, existing technical solutions for suppressing magnetic leakage in wireless charging mainly fall into two categories: The first type is the single-unit internal solution, which includes adding a passive shielding layer of ferrite and aluminum plate to the back of the coil, adding an active cancellation coil around the transmitting coil to generate a reverse magnetic field, and optimizing the coil coupling structure to reduce magnetic leakage. The common feature of this type of solution is that it solves the magnetic leakage problem within a single wireless charging system. Each charger needs to be equipped with independent shielding hardware. In multi-station scenarios, the hardware cost increases exponentially, and the passive shielding layer increases the weight and volume of the system, making it inconvenient for the flexible deployment of AGV charging stations.

[0004] The second type is the multi-machine coordination solution, which mainly involves time-sharing charging control. This involves using scheduling strategies to avoid multiple AGVs charging simultaneously, trading time for space to reduce peak magnetic leakage. This type of solution sacrifices charging efficiency and is not suitable for scenarios with intensive AGV scheduling.

[0005] Currently, there is no publicly available technical solution that utilizes cross-device phase coordination between two or more independent wireless charging transmitter systems to make their respective leakage magnetic fields spatially antiphase superimposed and cancel each other out, so as to ensure that the magnetic field in the public area meets safety standards. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a method and system for the coordinated mutual cancellation control of leakage magnetic field between multiple AGV wireless charging stations, without adding additional shielding hardware, when multiple AGV vehicles are simultaneously performing high-power wireless charging at adjacent wireless charging stations.

[0007] The technical solution adopted in this invention is as follows: This invention includes a method and system for collaborative cancellation of leakage magnetic field between multiple AGV wireless charging stations, the control method comprising the following steps: S1: When two AGV vehicles are wirelessly charged at adjacent wireless charging stations at the same time, each wireless charging station includes an independently powered and independently controlled wireless charging transmitter system. The transmitter controllers of the two adjacent wireless charging stations establish a collaborative connection through the workshop communication network. S2: After the two transmitter controllers establish a collaborative connection through the workshop communication network, they exchange their respective transmitter coil geometric parameters and the parking position information of the currently charged AGV. Based on the magnetic field superposition model of the two transmitter coils in the common area between two adjacent wireless charging stations, they calculate the optimal phase difference δ that minimizes the amplitude of the combined magnetic field in the common area. opt The public area is the area between two workstations determined based on the geometric parameters of the transmitting coil and the parking position information, preferably a passage area between two adjacent wireless charging workstations for personnel to pass through; S3: The two transmitter controllers use the voltage zero-crossing signal connected to the same AC bus as the synchronization time reference. The inverter of the first wireless charging station operates with an initial phase of 0°, and the inverter of the second wireless charging station operates with the optimal phase difference δ relative to the same zero-crossing point. opt As a delay before starting operation, the phase difference of the excitation currents of the two transmitting coils is locked at δ. opt And the synchronization phase error does not exceed ±1°; S4: During the collaborative charging process, when it is detected that the AGV vehicle at any wireless charging station has ended its charging request or the collaborative cancellation effect does not meet the preset conditions, the two transmitting controllers exit the collaborative mode within a preset time and return to their default phases for independent operation.

[0008] Furthermore, regarding the magnetic field superposition model and the optimal phase difference δ in step S2... optTo accommodate the real-time computing capabilities of embedded controllers, this invention employs a simplified model in practical engineering implementation. Specifically, the transmitting coil is modeled as a magnetic dipole, and the common region is simplified to a representative point on the line connecting the geometric centers of the two transmitting coils for magnetic field superposition analysis. The representative point can be the midpoint. Based on this simplified model, a functional relationship can be established between the amplitude of the synthesized magnetic field at the representative point and the phase difference δ of the excitation current of the transmitting coil. When the horizontal distance d between the geometric centers of the two transmitting coils is less than twice the equivalent radius R of the transmitting coils, i.e., d < 2R, the optimal phase difference δ... opt Calculate using the following formula: δ opt = 180° + arcsin(d / 2R) × 180° / π When d ≥ 2R, the magnetic fields of the two transmitting coils at the representative point can be regarded as independent magnetic dipole radiation under far-field conditions. Pure phase reversal can achieve maximum cancellation, hence δ opt It is determined to be 180°.

[0009] It should be noted that the simplified model and formula described above are approximate optimal solutions achievable in engineering. Their derivation assumes that the two transmitting coils are coaxial and neglects the influence of the receiving coil on the magnetic field distribution. In practical deployments, this formula can quickly give δ opt The initial value is then used to further approximate the actual optimal value through subsequent closed-loop fine-tuning steps.

[0010] Furthermore, regarding the synchronization accuracy guarantee in step S3, both of the aforementioned transmitter controllers include local crystal oscillators. The grid voltage zero-crossing signal serves as a coarse synchronization reference, and its detection may be subject to jitter due to grid harmonic interference. When the jitter of the zero-crossing signal exceeds the allowable range, the local crystal oscillator interpolates and calibrates the zero-crossing detection time to generate a higher-precision synchronization trigger signal, ensuring that the synchronization phase error of the two wireless charging station inverters does not exceed ±1°. If the local crystal oscillator calibration still cannot meet the ±1° accuracy requirement, this situation is used as a trigger condition for "the cooperative cancellation effect does not meet the preset conditions," and the system safely exits the cooperative mode and resumes independent operation.

[0011] Furthermore, in step S3, when the second wireless charging station smoothly transitions from independent working mode to collaborative mode, to ensure that the transition to collaborative mode does not impact the normal charging of the AGV, the inverter phase of the second wireless charging station is gradually adjusted to the optimal phase difference δ within a 100ms transition time in steps not exceeding 5°. opt During the transition period, the inverter phase of the first wireless charging station remains unchanged, and the charging power fluctuation does not exceed 5% of the rated power.

[0012] Furthermore, to further improve the cancellation effect, the method also includes a closed-loop fine-tuning step: a magnetic field strength sensor is deployed in the common area to monitor the amplitude of the synthesized magnetic field in real time; when the reduction ratio of the synthesized magnetic field amplitude in the cooperative mode does not reach the preset effect, for example, when the actual reduction ratio is significantly lower than the reduction ratio expected according to the model, it indicates that the optimal phase difference δ is caused by the deviation of the actual parking position of the AGV or the influence of the receiving coil. op The calculated value deviates from the actual optimal value. The two transmit controllers use a gradient search algorithm to find the optimal phase difference δ. op Fine-tuning is performed, with each adjustment step being ±0.5°, until the amplitude of the synthesized magnetic field measured by the field strength sensor reaches its minimum value.

[0013] Furthermore, the following situations are included, but are not limited to, cases where the synergistic cancellation effect in step S4 does not meet the preset conditions: Communication interruption: A communication interruption is determined when the heartbeat signal between two transmitter controllers is lost for more than 100ms. Phase deviation exceeding limits: The phase of the transmitting coil excitation current is monitored in real time by current sensors at each wireless charging station. When the actual phase difference deviates from the optimal phase difference δ, the phase deviation is exceeded. opt When the temperature exceeds ±10° and persists for more than 200ms; AGV vehicle displacement: The AGV vehicle is moved unexpectedly by detecting the rate of change of the reflected impedance of the transmitting coil. When the rate of change exceeds a preset threshold; Magnetic field exceeding limit: When the magnetic field sensor in the public area detects that the amplitude of the synthesized magnetic field exceeds the preset safety limit; Insufficient synchronization accuracy: When local crystal oscillator calibration still cannot meet the ±1° synchronization accuracy requirement.

[0014] The exit from collaborative mode is executed as follows: after both transmitter controllers receive the exit command at the same time, they will smoothly restore the phase of their respective inverters to the default value of independent working mode within 50ms. During this period, the charging power will not be interrupted to avoid power supply impact on the AGV vehicle.

[0015] Furthermore, the method also includes a multi-wireless charging station expansion step: when all N parallel wireless charging stations have AGV vehicles charging in place, N≥3, all wireless charging stations are numbered sequentially as 1, 2, ..., N; the transmitting systems of odd-numbered wireless charging stations are locked to the 0° phase group, and the transmitting systems of even-numbered wireless charging stations are locked to the 180° phase group; the transmitting controller of each wireless charging station only communicates with the transmitting controllers of the left and right adjacent wireless charging stations to form a chain communication topology, and obtains the phase status of adjacent wireless charging stations to determine the phase group that it should lock; when the AGV vehicle of any wireless charging station finishes charging and leaves, the wireless charging station exits the collaboration and broadcasts the departure status to the adjacent wireless charging stations, and the remaining wireless charging stations automatically reorganize the adjacent relationship to maintain the collaboration cancellation among the remaining wireless charging stations.

[0016] Furthermore, the workshop communication network is a CAN bus or a WiFi network.

[0017] Furthermore, a multi-AGV wireless charging station leakage magnetic flux collaborative cancellation control system, used to implement the aforementioned control method, includes: At least two adjacent wireless charging stations are provided, and each wireless charging station includes an independently powered transmitting coil, inverter and transmitting controller; The workshop communication network is used for data exchange between the transmitter controllers of each wireless charging station; The power grid synchronization module has its input end electrically connected to the same AC bus that supplies power to each wireless charging station, and its output end connected to the transmitter controller of each wireless charging station. It is used to extract and provide the voltage zero-crossing signal of the AC bus as a synchronization time reference for each transmitter controller. The transmitter controllers of the first and second wireless charging stations are configured to automatically establish a cooperative connection through the workshop communication network when AGV vehicles are detected charging at two adjacent wireless charging stations simultaneously. This allows them to exchange their respective transmitter coil geometric parameters and AGV vehicle parking position information, and calculate the optimal phase difference δ that minimizes the amplitude of the combined magnetic field in the common area between the two wireless charging stations. opt And based on the voltage zero-crossing signal provided by the power grid synchronization module, according to the optimal phase difference δ opt The output phase of the self-inverter at each wireless charging station is controlled to lock the phase difference of the excitation current of the two transmitting coils to the optimal phase difference δ. opt This allows for the mutual cancellation of magnetic leakage in public areas.

[0018] Furthermore, the system also includes a magnetic field strength sensor arranged in the public area, which is communicatively connected to the transmitter controllers of the two wireless charging stations, for real-time feedback of the synthesized magnetic field amplitude to determine the optimal phase difference δ. opt Perform closed-loop fine-tuning.

[0019] Furthermore, when the system is used in a multi-station expansion scenario, if all N parallel wireless charging stations have AGV vehicles charging in place (N≥3), all wireless charging stations are numbered sequentially as 1, 2, ..., N. The transmitting systems of odd-numbered wireless charging stations are locked to the 0° phase group, and the transmitting systems of even-numbered wireless charging stations are locked to the 180° phase group. The transmitting controller of each wireless charging station only communicates with the transmitting controllers of its left and right adjacent wireless charging stations, forming a chain communication topology, and obtains the phase state of adjacent wireless charging stations to determine the phase group it should lock. Thus, phase reversal is achieved between any adjacent stations. Cancellation: When the AGV vehicle at any of the wireless charging stations finishes charging and leaves, the wireless charging station exits the collaborative mode and broadcasts its departure status to the adjacent wireless charging stations. After receiving the departure broadcast, the adjacent stations automatically cancel the collaborative cancellation relationship with that station. The remaining wireless charging stations automatically re-determine the phase group to which they should belong based on the updated adjacency relationship. If the remaining stations can still form adjacent pairs, the collaborative cancellation among the remaining wireless charging stations is maintained. If there is a gap between the remaining stations, such as after wireless charging station 2 leaves, wireless charging station 1 and wireless charging station 3 are no longer adjacent, then each station will resume its independent working mode or reorganize into a new adjacent cancellation group.

[0020] The beneficial effects of this invention are: 1. Through the method of this invention, the amplitude of the synthetic magnetic field in the public area can be significantly reduced, thereby ensuring that its peak value meets the requirements of electromagnetic safety standards such as ICNIRP; The technical approach is novel: It is the first time to propose cross-device phase coordination between two wireless charging transmission systems belonging to different AGV vehicles, with independent power supply and independent control, to achieve mutual cancellation of magnetic leakage in the common area between workstations through the spatial anti-phase superposition of magnetic fields. This breaks away from the inherent technical idea of ​​shielding within a single machine and belongs to a system-level magnetic leakage suppression solution. Zero hardware additions: There is absolutely no need to add compensation coils, thicken metal shielding layers, or add absorbing materials. Leakage magnetic field suppression is achieved solely through software control using this method, resulting in zero hardware costs and an extremely low barrier to entry for modification. High compatibility: It is compatible with the existing single AGV vehicle charging mode. When only one AGV vehicle is charging, it automatically returns to the independent working mode without modifying the original single-machine charging logic. Complete control closed loop: From detection interconnection, spatial modeling to calculate the optimal phase, carrier synchronization phase-locking, smooth switching between single and dual modes, real-time closed-loop fine-tuning to multi-station expansion and idle reassembly, a complete control link is formed, and the scheme is highly reproducible. Comprehensive safety mechanisms: Built-in multiple fault protection mechanisms for communication interruption, phase deviation, vehicle displacement, magnetic field exceeding standard, and insufficient synchronization accuracy ensure that the system can safely return to independent working mode when the collaborative mode fails, without affecting the normal charging of the AGV vehicle.

[0021] Flexible scalability: Through odd-even grouping and chain communication topology, it can be smoothly expanded to any number of parallel wireless charging stations; when some stations are idle, the system can automatically reorganize the adjacent relationships and systematically suppress the leakage magnetic field level of the entire AGV charging channel. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the principle of the leakage magnetic field collaborative mutual cancellation control system between dual wireless charging stations; Figure 2 This is a flowchart of the control method of the present invention; Figure 3 This is a schematic diagram of the odd-even grouping strategy for multi-station expansion. Detailed Implementation

[0023] In this embodiment, the present invention includes a method and system for collaborative cancellation of leakage magnetic field between multiple AGV wireless charging stations, the control method comprising the following steps: S1: When two AGV vehicles are wirelessly charged at adjacent wireless charging stations at the same time, each wireless charging station includes an independently powered and independently controlled wireless charging transmitter system. The transmitter controllers of the two adjacent wireless charging stations establish a collaborative connection through the workshop communication network. S2: After the two transmitter controllers establish a collaborative connection through the workshop communication network, they exchange their respective transmitter coil geometric parameters and the parking position information of the currently charged AGV. Based on the magnetic field superposition model of the two transmitter coils in the common area between two adjacent wireless charging stations, they calculate the optimal phase difference δ that minimizes the amplitude of the combined magnetic field in the common area. opt ; S3: The two transmitter controllers use the voltage zero-crossing signal connected to the same AC bus as the synchronization time reference. The inverter of the first wireless charging station operates with an initial phase of 0°, and the inverter of the second wireless charging station operates with the optimal phase difference δ relative to the same zero-crossing point. opt As a delay before starting operation, the phase difference of the excitation currents of the two transmitting coils is locked at δ. opt And the synchronization phase error does not exceed ±1°; S4: During the collaborative charging process, when it is detected that the AGV vehicle at any wireless charging station has ended its charging request, or when the communication between the two transmitter controllers is interrupted or the collaborative cancellation effect does not meet the preset conditions, the two transmitter controllers shall exit the collaborative mode within a preset time and return to their default phases for independent operation.

[0024] In this embodiment, the workshop communication network mentioned in step S1 is a CAN bus or a WiFi network; the optimal phase difference δ mentioned in step S2 opt The calculation is based on a simplified model that treats the transmitting coil as an equivalent magnetic dipole. The common region is simplified to a representative point on the line connecting the geometric centers of the two transmitting coils, and magnetic field superposition analysis is performed. The common region is the area between two wireless charging stations determined based on the geometric parameters of the transmitting coils and the parking position information of the AGV vehicle. When the horizontal distance d between the geometric centers of the two transmitting coils is less than twice the equivalent radius R of the transmitting coils, the optimal phase difference δ... opt Calculate using the following formula: δ opt = 180° + arcsin(d / 2R) × 180° / π When d ≥ 2R, δ opt It is determined to be 180°.

[0025] In this embodiment, both of the transmit controllers in step S3 include a local crystal oscillator. When the zero-crossing signal of the grid voltage jitters due to interference, the local crystal oscillator performs interpolation calibration on the zero-crossing detection time to ensure that the synchronization phase error does not exceed ±1°. When the local crystal oscillator calibration still cannot meet the ±1° accuracy requirement, the exit from the cooperative mode is triggered.

[0026] In this embodiment, in step S3, when the second wireless charging station enters the collaborative mode from the independent working mode, the inverter phase of the second wireless charging station is gradually adjusted to the optimal phase difference δ in steps of no more than 5° within a 100ms transition time. opt During the transition period, the inverter phase of the first wireless charging station remains unchanged, and the charging power fluctuation does not exceed 5% of the rated power.

[0027] In this embodiment, the method further includes a closed-loop fine-tuning step: a magnetic field strength sensor is deployed in the common area to monitor the amplitude of the synthesized magnetic field in real time; when the reduction ratio of the synthesized magnetic field amplitude in the cooperative mode does not reach the preset effect, the two transmission controllers use a gradient search algorithm to adjust the optimal phase difference δ. op Fine-tuning is performed, with each adjustment step being ±0.5°, until the amplitude of the synthesized magnetic field reaches its minimum value.

[0028] In this embodiment, the method further includes a multi-wireless charging station expansion step: when all N parallel wireless charging stations have AGV vehicles charging in place, N≥3, all wireless charging stations are numbered sequentially as 1, 2, ..., N; the transmitting systems of odd-numbered wireless charging stations are locked to the 0° phase group, and the transmitting systems of even-numbered wireless charging stations are locked to the 180° phase group; the transmitting controller of each wireless charging station only communicates with the transmitting controllers of the left and right adjacent wireless charging stations to form a chain communication topology, and obtains the phase status of the adjacent wireless charging stations to determine the phase group that it should lock; when the AGV vehicle of any wireless charging station finishes charging and leaves, the wireless charging station exits the cooperative mode and broadcasts the departure status to the adjacent wireless charging stations, and the remaining wireless charging stations automatically reorganize the adjacent relationship to maintain the cooperative cancellation among the remaining wireless charging stations.

[0029] In this embodiment, the failure of the collaborative cancellation effect in step S4 to meet the preset conditions includes: Communication interruption: A communication interruption is determined when the heartbeat signal between two transmitter controllers is lost for more than 100ms. Phase deviation exceeding limits: The phase of the transmitting coil excitation current is monitored in real time by current sensors at each wireless charging station. When the actual phase difference deviates from the optimal phase difference δ, the phase deviation is exceeded. opt When the temperature exceeds ±10° and persists for more than 200ms; AGV vehicle displacement: The AGV vehicle is moved unexpectedly by detecting the rate of change of the reflected impedance of the transmitting coil. When the rate of change exceeds a preset threshold; Magnetic field exceeding limit: When the magnetic field sensor in the public area detects that the amplitude of the synthesized magnetic field exceeds the preset safety limit; Insufficient synchronization accuracy: When local crystal oscillator calibration still cannot meet the ±1° synchronization accuracy requirement.

[0030] The exit from collaborative mode is executed as follows: after both transmitter controllers receive the exit command at the same time, they will smoothly restore the phase of their respective inverters to the default value of independent working mode within 50ms. During this period, the charging power will not be interrupted to avoid power supply impact on the AGV vehicle.

[0031] In this embodiment, a multi-AGV wireless charging station leakage magnetic flux collaborative cancellation control system is used to implement the control method, characterized in that it includes: At least two adjacent wireless charging stations are provided, and each wireless charging station includes an independently powered transmitting coil, inverter and transmitting controller; The workshop communication network is used for data exchange between the transmitter controllers of each wireless charging station; The power grid synchronization module has its input end electrically connected to the same AC bus that supplies power to each wireless charging station, and its output end connected to the transmitter controller of each wireless charging station. It is used to extract and provide the voltage zero-crossing signal of the AC bus as a synchronization time reference for each transmitter controller. The transmitter controllers of the first and second wireless charging stations are configured to automatically establish a cooperative connection through the workshop communication network when AGV vehicles are detected charging at two adjacent wireless charging stations simultaneously. This allows them to exchange their respective transmitter coil geometric parameters and AGV vehicle parking position information, and calculate the optimal phase difference δ that minimizes the amplitude of the combined magnetic field in the common area between the two wireless charging stations. opt And based on the voltage zero-crossing signal provided by the power grid synchronization module, according to the optimal phase difference δ opt The output phase of the self-inverter at each wireless charging station is controlled to lock the phase difference of the excitation current of the two transmitting coils to the optimal phase difference δ. opt This allows for the mutual cancellation of magnetic leakage in public areas.

[0032] In this embodiment, the system further includes a magnetic field strength sensor arranged in the public area, which is communicatively connected to the transmitter controllers of the two wireless charging stations, for real-time feedback of the synthesized magnetic field amplitude to adjust the optimal phase difference δ. opt Perform closed-loop fine-tuning.

[0033] In this embodiment, when the system is used in a multi-station scenario, if there are AGV vehicles charging in N parallel wireless charging stations, N≥3, each station is divided into two groups according to odd and even numbers. The phase lock of the transmission system of the odd-numbered station is 0°, and the phase lock of the transmission system of the even-numbered station is 180°. The transmission controller of each wireless charging station only establishes a communication link with the transmission controllers of the left and right adjacent wireless charging stations, forming a chain topology. When the AGV vehicle of any wireless charging station finishes charging and leaves, the remaining wireless charging stations automatically reorganize their adjacent relationships and maintain cooperative cancellation.

[0034] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0035] Implementation Method 1: Dual-Station Scenario like Figure 1 As shown, this embodiment provides a dual-station AGV wireless charging station leakage magnetic field cooperative mutual cancellation control system, including a first wireless charging station A and a second wireless charging station B arranged adjacent to each other.

[0036] The first wireless charging station A includes: a transmitting coil TA, an inverter InvA, and a transmitting controller CtrlA. The second wireless charging station B includes: a transmitting coil TB, an inverter InvB, and a transmitting controller CtrlB. The transmitting systems of the first wireless charging station A and the second wireless charging station B are independently powered, drawing power from the same AC bus.

[0037] Transmitter controllers CtrlA and CtrlB establish a communication link via the existing CAN bus in the workshop. The power grid synchronization module extracts the zero-crossing voltage signal from the AC bus and sends it to transmitter controllers CtrlA and CtrlB respectively as a synchronization time reference.

[0038] In this embodiment, the target common area is defined as the passageway P between two adjacent workstations for personnel passage. To facilitate magnetic field calculation and evaluation, the midpoint of the line segment projected onto the ground of the passageway connecting the geometric centers of transmitting coils TA and TB is selected as the representative point of this common area. The magnetic field strength sensor HP is positioned at this representative point and is communicatively connected to the transmitting controllers CtrlA and CtrlB.

[0039] AGV-1 is wirelessly charged above the first wireless charging station A, with its receiving coil RA coupled to its transmitting coil TA. AGV-2 is wirelessly charged above the second wireless charging station B, with its receiving coil RB coupled to its transmitting coil TB.

[0040] like Figure 2 As shown, the collaborative cancellation control process is as follows: First, the transmitter controller CtrlA detects that AGV-1 is charging at the first wireless charging station A and broadcasts the occupancy status of the first wireless charging station A via the CAN bus. Then, the transmitter controller CtrlB detects that AGV-2 is charging at the second wireless charging station B and simultaneously receives the occupancy broadcast for the first wireless charging station A. Determining that the conditions for adjacent dual-station charging are met, it initiates a coordination request to the transmitter controller CtrlA. After a handshake confirmation, a coordination connection is established, and the system enters coordination mode.

[0041] Next, the transmitting controllers CtrlA and CtrlB exchange the equivalent radius R and geometric center coordinates of their respective transmitting coils, and determine the actual horizontal distance d between the geometric centers of transmitting coils TA and TB based on the parking detection results of AGV-1 and AGV-2 vehicles. Using a simplified model that treats the transmitting coils as equivalent to magnetic dipoles, the representative point of the common area (the midpoint of the line connecting the geometric centers of the two coils) is used as the magnetic field superposition analysis point. A functional relationship is established between the synthesized magnetic field at this representative point and the phase difference of the excitation current between transmitting coils TA and TB, and the optimal phase difference is calculated. In this embodiment, R = 0.3m, d = 1.2m. Since d = 1.2m, 2R = 0.6m, and d ≥ 2R, the optimal phase difference δ is... opt It is determined to be 180°.

[0042] Then, the transmitter controller CtrlA, acting as the master, controls the inverter InvA to start operating with an initial phase of 0° at the moment the grid voltage zero-crossing signal is triggered. The transmitter controller CtrlB, acting as the slave, controls the inverter InvB to start operating after a delay of 180° electrical angle time based on the same grid voltage zero-crossing signal trigger time. Both controllers use their local crystal oscillators to interpolate and calibrate the zero-crossing detection to ensure that the phase difference error of the excitation current of the transmitter coil TA and the transmitter coil TB does not exceed ±1°.

[0043] When switching to cooperative mode, the transmitter controller CtrlB controls the inverter InvB to gradually adjust the phase to 180° within 100ms in steps of no more than 5° each time. During the transition, the transmitter controller CtrlA keeps the phase unchanged, and the charging power fluctuation is controlled within 5% of the rated power.

[0044] After entering steady-state collaborative charging, the magnetic field sensor HP at point P in the channel region continuously monitors the amplitude of the synthesized magnetic field. If the detected reduction in magnetic field amplitude does not meet expectations, it indicates a deviation between the actual parking position of AGV-1 or AGV-2 and the detected value, or that the receiving coil RA or RB has affected the magnetic field distribution, resulting in an insufficient optimal phase difference δ. opt The calculated value deviates from the actual optimal value. Transmit controllers CtrlA and CtrlB initiate a gradient search algorithm to find the optimal phase difference δ. opt Fine-tuning is performed in ±0.5° increments until the magnetic field amplitude measured by the magnetic field sensor HP reaches its minimum value. This ensures that the peak magnetic field in channel region P meets electromagnetic safety standards.

[0045] During charging, the system continuously monitors the following fault conditions: Communication heartbeat monitoring: Transmit controller CtrlA and transmit controller CtrlB send a heartbeat signal every 20ms. If no heartbeat is received from the other party for 5 consecutive times (100ms), communication is considered interrupted. Phase deviation monitoring: The excitation current waveform is sampled in real time by current sensors at each station, and the actual phase difference between the two currents is calculated. If the deviation from the optimal phase difference δ is detected, the phase deviation is monitored. opt If the angle exceeds ±10° and persists for 200ms, it is considered a phase loss of control. Vehicle movement monitoring: Determine whether AGV-1 or AGV-2 has moved unexpectedly by measuring the rate of change of reflected impedance; Magnetic field exceedance monitoring: If the measured value of the magnetic field sensor HP exceeds the safety limit, it is determined to be ineffective. Synchronization accuracy monitoring: When the crystal oscillator calibration still cannot meet the ±1° synchronization accuracy requirement, synchronization failure is determined.

[0046] When any fault condition is triggered, both transmitter controllers CtrlA and CtrlB simultaneously restore the phases of their respective inverters InvA and InvB to their default values ​​in independent mode within 50ms. The charging power is not interrupted, the system returns to its independent operating state, and an alarm message is sent through the CAN bus.

[0047] When AGV-1 or AGV-2 finishes charging and sends a termination request, it will restore the default phase within 50ms after detecting that the other AGV is offline, and return to independent mode to continue charging another AGV-1 or AGV-2.

[0048] Implementation Method 2: Multi-Workstation Expansion Scenario like Figure 3 As shown, for 5 wireless charging stations arranged side by side (numbered 1 to 5), when all stations have AGV vehicles charging in place, an odd-even grouping strategy is adopted: The launch systems numbered 1, 3, and 5 (odd-numbered positions) are locked to the 0° phase group; The launch systems numbered 2 and 4 (even-numbered positions) are locked to the 180° phase group.

[0049] Each workstation controller forms a chain communication topology via a CAN bus: Controller 1 communicates with Controller 2, Controller 2 communicates with Controller 1 and 3, Controller 3 communicates with Controller 2 and 4, and so on. Each controller only needs to obtain the phase status of its left and right adjacent workstations to determine its own phase group.

[0050] As a result, the emission excitation current can be canceled out between any two adjacent workstation pairs (1-2, 2-3, 3-4, 4-5), and the leakage magnetic field level of the entire charging channel is systematically suppressed, meeting the electromagnetic safety standard requirements.

[0051] When one of the AGVs finishes charging and leaves (for example, the AGV at station 2 finishes charging), the controller at station 2 exits the collaborative mode and broadcasts its departure status to the adjacent stations 1 and 3. Upon receiving the departure broadcast, stations 1 and 3 detect that they are no longer adjacent (separated by the empty station 2) and each resumes its independent working mode, issuing an alarm notification via the CAN bus. The remaining stations 3-4-5 reassess their adjacency relationships: station 3 resumes its independent mode, while stations 4 and 5 remain adjacent, maintaining a 180° opposite collaborative mode.

[0052] Although the embodiments of the present invention are described with reference to actual solutions, they do not constitute a limitation on the meaning of the present invention. Modifications to the embodiments and combinations with other solutions based on this specification will be obvious to those skilled in the art.

Claims

1. A method for collaborative cancellation of leakage magnetic flux between multiple AGV wireless charging stations, characterized in that, Includes the following steps: S1: When two AGV vehicles are wirelessly charged at adjacent wireless charging stations at the same time, each wireless charging station includes an independently powered and independently controlled wireless charging transmitter system. The transmitter controllers of the two adjacent wireless charging stations establish a collaborative connection through the workshop communication network. S2: After the two transmitter controllers establish a collaborative connection through the workshop communication network, they exchange their respective transmitter coil geometric parameters and the parking position information of the currently charged AGV. Based on the magnetic field superposition model of the two transmitter coils in the common area between two adjacent wireless charging stations, they calculate the optimal phase difference δ that minimizes the amplitude of the combined magnetic field in the common area. opt ; S3: The two transmitter controllers use the voltage zero-crossing signal connected to the same AC bus as the synchronization time reference. The inverter of the first wireless charging station operates with an initial phase of 0°, and the inverter of the second wireless charging station operates with the optimal phase difference δ relative to the same zero-crossing point. opt As a delay before starting operation, the phase difference of the excitation currents of the two transmitting coils is locked at δ. opt ; S4: During the collaborative charging process, when it is detected that the AGV vehicle at any wireless charging station has ended its charging request, or when the communication between the two transmitter controllers is interrupted or the collaborative cancellation effect does not meet the preset conditions, the two transmitter controllers shall exit the collaborative mode within a preset time and return to their default phases for independent operation.

2. The method for collaborative cancellation of leakage magnetic field between multiple AGV wireless charging stations according to claim 1, characterized in that: The workshop communication network mentioned in step S1 is a CAN bus or a WiFi network; the optimal phase difference δ mentioned in step S2 opt The calculation is based on a simplified model that treats the transmitting coil as an equivalent magnetic dipole. The common region is simplified to a representative point on the line connecting the geometric centers of the two transmitting coils, and magnetic field superposition analysis is performed. The common region is the area between two wireless charging stations determined based on the geometric parameters of the transmitting coils and the parking position information of the AGV vehicle. When the horizontal distance d between the geometric centers of the two transmitting coils is less than twice the equivalent radius R of the transmitting coils, the optimal phase difference δ... opt Calculate using the following formula: δ opt = 180° + arcsin(d / 2R) × 180° / π , When d ≥ 2R, δ opt It is determined to be 180°.

3. The method for collaborative cancellation of leakage magnetic field between multiple AGV wireless charging stations according to claim 1, characterized in that: In step S3, both of the transmitting controllers include a local crystal oscillator. When the zero-crossing signal of the mains voltage jitters due to interference, the local crystal oscillator interpolates and calibrates the zero-crossing detection time to ensure that the synchronization phase error does not exceed ±1°. When the local crystal oscillator calibration still cannot meet the ±1° accuracy requirement, the exit from the cooperative mode is triggered.

4. The method for collaborative cancellation of leakage magnetic field between multiple AGV wireless charging stations according to claim 1, characterized in that: In step S3, when the second wireless charging station enters the collaborative mode from the independent working mode, the inverter phase of the second wireless charging station is gradually adjusted to the optimal phase difference δ in steps of no more than 5° within a 100ms transition time. opt During the transition period, the inverter phase of the first wireless charging station remains unchanged, and the charging power fluctuation does not exceed 5% of the rated power.

5. The method for collaborative cancellation of leakage magnetic flux between multiple AGV wireless charging stations according to claim 1, characterized in that: The method further includes a closed-loop fine-tuning step: deploying a magnetic field strength sensor in the public area to monitor the amplitude of the synthesized magnetic field in real time; When the reduction ratio of the synthesized magnetic field amplitude in the cooperative mode does not reach the preset effect, the two transmission controllers use a gradient search algorithm to find the optimal phase difference δ. op Fine-tuning is performed, with each adjustment step being ±0.5°, until the amplitude of the synthesized magnetic field reaches its minimum value.

6. The method for collaborative cancellation of leakage magnetic flux between multiple AGV wireless charging stations according to claim 1, characterized in that: The method further includes a multi-wireless charging station expansion step: when all N parallel wireless charging stations have AGV vehicles charging in place, N≥3, all wireless charging stations are numbered sequentially as 1, 2, ..., N; the transmitting systems of odd-numbered wireless charging stations are locked to the 0° phase group, and the transmitting systems of even-numbered wireless charging stations are locked to the 180° phase group; the transmitting controller of each wireless charging station only communicates with the transmitting controllers of the left and right adjacent wireless charging stations to form a chain communication topology, and obtains the phase status of adjacent wireless charging stations to determine the phase group that it should lock; when the AGV vehicle of any wireless charging station finishes charging and leaves, the wireless charging station exits the collaborative mode and broadcasts the departure status to the adjacent wireless charging stations, and the remaining wireless charging stations automatically reorganize the adjacent relationship to maintain the collaborative cancellation among the remaining wireless charging stations.

7. The method for collaborative cancellation of leakage magnetic flux between multiple AGV wireless charging stations according to claim 1, characterized in that: The following conditions are not met in step S4 regarding the collaborative cancellation effect: Communication interruption: A communication interruption is determined when the heartbeat signal between two transmitter controllers is lost for more than 100ms. Phase deviation exceeding limits: The phase of the transmitting coil excitation current is monitored in real time by current sensors at each wireless charging station. When the actual phase difference deviates from the optimal phase difference δ, the phase deviation is exceeded. opt When the temperature exceeds ±10° and persists for more than 200ms; AGV vehicle displacement: The AGV vehicle is moved unexpectedly by detecting the rate of change of the reflected impedance of the transmitting coil. When the rate of change exceeds a preset threshold; Magnetic field exceeding limit: When the magnetic field sensor in the public area detects that the amplitude of the synthesized magnetic field exceeds the preset safety limit; Insufficient synchronization accuracy: When local crystal oscillator calibration still cannot meet the ±1° synchronization accuracy requirement; The exit from collaborative mode is executed as follows: after both transmitter controllers receive the exit command at the same time, they will smoothly restore the phase of their respective inverters to the default value of independent working mode within 50ms. During this period, the charging power will not be interrupted to avoid power supply impact on the AGV vehicle.

8. A multi-AGV wireless charging station leakage magnetic flux collaborative cancellation control system, used to implement the control method according to any one of claims 1 to 7, characterized in that, include: At least two adjacent wireless charging stations are provided, and each wireless charging station includes an independently powered transmitting coil, inverter and transmitting controller; The workshop communication network is used for data exchange between the transmitter controllers of each wireless charging station; The power grid synchronization module has its input end electrically connected to the same AC bus that supplies power to each wireless charging station, and its output end connected to the transmitter controller of each wireless charging station. It is used to extract and provide the voltage zero-crossing signal of the AC bus as a synchronization time reference for each transmitter controller. The transmitter controllers of the first and second wireless charging stations are configured to automatically establish a cooperative connection through the workshop communication network when AGV vehicles are detected charging at two adjacent wireless charging stations simultaneously. This allows them to exchange their respective transmitter coil geometric parameters and AGV vehicle parking position information, and calculate the optimal phase difference δ that minimizes the amplitude of the combined magnetic field in the common area between the two wireless charging stations. opt And based on the voltage zero-crossing signal provided by the power grid synchronization module, according to the optimal phase difference δ opt The output phase of the self-inverter at each wireless charging station is controlled to lock the phase difference of the excitation current of the two transmitting coils to the optimal phase difference δ. opt This allows for the mutual cancellation of magnetic leakage in public areas.

9. The multi-AGV wireless charging station leakage magnetic field collaborative mutual cancellation control system according to claim 8, characterized in that: The system also includes a magnetic field strength sensor located in the public area, which is communicatively connected to the transmitter controllers of the two wireless charging stations, for real-time feedback of the synthesized magnetic field amplitude to determine the optimal phase difference δ. opt Perform closed-loop fine-tuning.

10. The multi-AGV wireless charging station leakage magnetic field collaborative mutual cancellation control system according to claim 8, characterized in that: When the system is used in a multi-station scenario, if there are AGV vehicles charging in N parallel wireless charging stations, N≥3, each station is divided into two groups according to odd and even numbers. The phase lock of the transmission system of the odd-numbered station is 0°, and the phase lock of the transmission system of the even-numbered station is 180°. The transmission controller of each wireless charging station only establishes a communication link with the transmission controllers of the left and right adjacent wireless charging stations, forming a chain topology. When the AGV vehicle of any wireless charging station finishes charging and leaves, the remaining wireless charging stations automatically reorganize the adjacent relationship and maintain cooperative cancellation.

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