An alignment detection self-checking method and system for wireless charging

Abstract

The application belongs to the technical field of wireless charging, and particularly relates to a method and system for alignment detection and self-checking for wireless charging, which comprises the following steps: sending one driving command to each of N inverters in an alignment detection device, so as to excite N secondary side coils in the alignment detection device to generate N voltages; connecting the N inverters with N primary side coils one by one through AC terminals; connecting the N primary side coils with the N secondary side coils; collecting N output voltages generated by the N primary side coils, and determining the size relationship between the output voltages and a set voltage threshold; if at most one voltage among the collected output voltages is greater than or equal to the set voltage threshold, outputting a self-checking result of failed alignment detection; and if at least two voltages among the collected output voltages are greater than or equal to the set voltage threshold, outputting a self-checking result of normal alignment detection. Thus, the application solves the problem of low reliability of the alignment detection device in the prior art.

Description

Technical Field

[0001] This invention belongs to the field of wireless charging technology, specifically relating to a self-testing method and system for alignment detection in wireless charging. Background Technology

[0002] With the rapid development of wireless charging technology, electric vehicles are gradually adopting wireless charging. Wireless charging for electric vehicles uses sealed installation and contactless operation, making it adaptable to harsh weather conditions such as humidity. It eliminates the need to plug and unplug charging guns, reducing the risk of electric shock, improving user experience, and enhancing safety. It simplifies the charging process, enables unmanned management with network connectivity, and requires no professional personnel. In the future, it can be integrated with autonomous driving and vehicle-to-everything (V2X) communication, reducing the operating costs of charging stations while providing convenience for users. Currently, wireless charging still faces some technical challenges, the most critical being the alignment of the ground-based transmitting coil and the vehicle-based receiving coil. Since the efficiency of wireless charging is highly sensitive to changes in the position of the transmitting and receiving coils, misalignment will significantly reduce charging efficiency, and excessive misalignment may even prevent charging altogether. Therefore, accurate alignment of the transmitting and receiving coils is crucial for ensuring normal charging and improving charging efficiency. Currently, alignment detection equipment is mostly used to assist in the alignment of wireless charging coils. However, due to different vehicle models and different driver skills, multiple adjustments are always required to achieve successful alignment. Sometimes, the alignment detection equipment itself has problems. Since the cause is unknown, drivers will only suspect that the alignment detection equipment itself is faulty after repeated adjustments. In short, this method is both time-consuming and resource-intensive, and has low reliability. Summary of the Invention

[0003] The purpose of this invention is to provide a self-testing method and system for alignment detection in wireless charging, so as to solve the problem of low reliability of alignment detection equipment in the prior art.

[0004] To solve the above-mentioned technical problems, the technical solution provided by this invention and the corresponding beneficial effects of the technical solution are as follows:

[0005] The present invention provides a self-testing method for alignment detection in wireless charging, comprising the following steps:

[0006] 1) Send one drive command to each of the N inverters in the alignment detection device to induce N voltages in the N secondary coils of the alignment detection device, where N ≥ 1; the N inverters are located between the DC power supply and the N primary coils, and the AC terminals of the N inverters are connected to the N primary coils one by one; the N primary coils are induced to connect to the N secondary coils.

[0007] 2) Collect N output voltages generated by N primary coils and determine the relationship between the output voltage and the set voltage threshold: If at most one of the collected output voltages is greater than or equal to the set voltage threshold, output a self-test result indicating that the alignment detection cannot be performed; if at least two of the collected output voltages are greater than or equal to the set voltage threshold, output a self-test result indicating that the alignment detection is normal.

[0008] The beneficial effects of the above technical solution are as follows: Before alignment detection, the present invention first sends a drive command to the alignment detection device, then collects the output voltage from the output terminal, and then determines whether the output voltage is greater than a set voltage threshold. Based on the number of output voltages exceeding the set voltage threshold, it determines whether alignment detection can be performed. This realizes a self-test function before alignment detection. Adding a self-test function before alignment detection can predict the system's working status in advance, report faults in advance, improve the reliability of the alignment detection device, and facilitate early prediction of device status or timely adoption of backup plans. On the other hand, performing alignment function detection only after confirming that the device logic is normal after self-testing facilitates rapid alignment and improves the alignment success rate.

[0009] Furthermore, in step 2), the output voltage information corresponding to the output voltage that is less than the set voltage threshold also needs to be output.

[0010] Furthermore, in step 2), if at most one of the acquired output voltages is greater than or equal to the set voltage threshold, a stop alignment detection command needs to be sent; if at least two of the acquired output voltages are greater than or equal to the set voltage threshold, an alignment detection command needs to be sent.

[0011] Furthermore, the voltage threshold value is determined according to the following formula:

[0012]

[0013] Where k is a coefficient obtained based on the magnetic field distribution, core distribution, and current magnitude, 0 < k < 1, r is the coupling path, d is the secondary coil size, and u 激励 This is the primary input excitation voltage.

[0014] Furthermore, N = 4.

[0015] Furthermore, the driving command is a PWM wave.

[0016] This invention provides an alignment detection system, which includes a control terminal and an alignment detection device. The alignment detection device includes N inverters, N primary coils, N secondary coils, and a detection circuit. The AC terminals of the N inverters are connected one-to-one with the N primary coils. The N primary coils are inductively connected to the N secondary coils. The detection circuit is used to collect N output voltages generated and output by the N secondary coils in the alignment detection device. The control terminal controls and connects to each inverter and samples the detection circuit. The control terminal is used to: send one drive command to each of the N inverters to excite the N secondary coils in the alignment detection device to generate N voltages, N≥1; receive the N output voltages collected by the detection circuit; and determine the relationship between the output voltages and a set voltage threshold. If at most one of the collected output voltages is greater than or equal to the set voltage threshold, a self-test result indicating that alignment detection is not possible is output. If at least two of the collected output voltages are greater than or equal to the set voltage threshold, a self-test result indicating that alignment detection is normal is output.

[0017] The beneficial effects of the above technical solution are as follows: Before alignment detection, the present invention first sends a drive command to the alignment detection device, then collects the output voltage from the output terminal, and then determines whether the output voltage is greater than a set voltage threshold. Based on the number of output voltages exceeding the set voltage threshold, it determines whether alignment detection can be performed. This realizes a self-test function before alignment detection. Adding a self-test function before alignment detection can predict the system's working status in advance, report faults in advance, improve the reliability of the alignment detection device, and facilitate early prediction of device status or timely adoption of backup plans. On the other hand, performing alignment function detection only after confirming that the device logic is normal after self-testing facilitates rapid alignment and improves the alignment success rate.

[0018] Furthermore, the control terminal includes: a ground control terminal, a vehicle-mounted control terminal, and an external pile body control terminal; the ground control terminal controls and connects to each inverter, and is used to send one drive command to each inverter; the vehicle-mounted control terminal is connected to a sampling and detection circuit, and is used to acquire N output voltages collected by the detection circuit, determine the relationship between the output voltage and the set voltage threshold, and output self-test results; the external pile body control terminal controls and connects to the ground control terminal and the vehicle-mounted control terminal, and is used to send control commands to the ground control terminal and to receive self-test results.

[0019] Furthermore, N = 4.

[0020] Furthermore, the external pile control terminal also needs to send the following information based on the self-test results: if the self-test result is normal alignment detection, then send an alignment detection command to the ground control terminal; if the self-test result is that alignment detection is not possible, then send a stop alignment detection command to the ground control terminal. Attached Figure Description

[0021] Figure 1This is a schematic diagram showing the position of the transmitting coil in the ground-end equipment of an alignment detection system according to the present invention;

[0022] Figure 2 This is a schematic diagram showing the position of the receiving coil in the vehicle-mounted terminal device of an alignment detection system according to the present invention;

[0023] Figure 3 This is a simplified circuit diagram of the alignment detection device in the alignment detection system of the present invention;

[0024] Figure 4 This is a structural block diagram of an alignment detection device in an alignment detection system according to the present invention;

[0025] Figure 5 This is a schematic diagram of a full-bridge topology of an inverter in an alignment detection system according to the present invention;

[0026] Figure 6 This is a schematic diagram of a half-bridge topology of an inverter in an alignment detection system according to the present invention;

[0027] Figure 7 This is a flowchart of an alignment detection self-test method for wireless charging according to the present invention. Detailed Implementation

[0028] The purpose of this invention is to provide a self-testing method for alignment detection in automobiles equipped with wireless charging devices. Before alignment detection, a self-test of the alignment detection device is performed. This allows for early prediction of the system's operating status, timely reporting of faults, and improved reliability of the alignment detection device. It also facilitates early detection of device status or timely adoption of backup solutions. Furthermore, performing alignment function testing only after confirming the device's logic is normal facilitates rapid alignment and improves the alignment success rate. The main concept of this invention is as follows: Before alignment detection, a drive command is sent to the inverter in the alignment detection device. Then, the voltage at the output terminal of the alignment detection device is collected. Based on the voltage and its comparison with a set voltage threshold, it is determined whether this voltage is normal. If the voltage is normal, this device is normal, thus achieving self-testing of the device and determining whether each device participating in the alignment detection is normal and has detection capability. After self-testing, if alignment detection cannot be performed, fault information is reported promptly; if alignment detection can be performed, the position determination result is reported after self-testing.

[0029] The principle of this invention is that the voltage generated on the secondary side of the alignment detection system comes from the alternating voltage signal emitted by the primary side excitation source. This phenomenon is based on the premise that the primary and secondary side detection circuits are functioning normally. If there is a problem with the detection circuit, the signal generated on the secondary side will be a "constant voltage signal" instead of a periodically changing alternating current.

[0030] An embodiment of an alignment detection system:

[0031] An embodiment of the alignment detection system of the present invention includes a control terminal and an alignment detection device. The alignment detection device includes four inverters, four primary coils, four secondary coils, and a detection circuit. The AC terminals of the four inverters are connected one-to-one with the four primary coils. The N primary coils are inductively connected to the N secondary coils. The output terminals of the four secondary coils are sampled and connected one-to-one with the four interfaces of the detection circuit. The control terminal controls and connects to each inverter. The detection circuit is used to collect the four output voltages from the four secondary coils in the alignment detection device and send them to the control terminal. The control terminal includes a ground control terminal, a vehicle control terminal, and an external pile control terminal. The ground control terminal is connected to the inverters and is used to send four drive commands to the inverters. The vehicle control terminal is sampled and connected to the detection circuit to obtain the four output voltages collected by the detection circuit, determine the relationship between the output voltage and the set voltage threshold, and output a self-test result. The external pile control terminal controls and connects to the ground control terminal and the vehicle control terminal, and is used to send control commands to the ground control terminal and to receive the self-test result. In this invention, alignment of the primary and secondary coils is not required. However, when there is a positional misalignment between the primary and secondary coils, it is possible that a signal generated by one primary coil can be sensed by both secondary coils, for example, when the primary coil is exactly at the center of the two receiving coils. Therefore, this invention is used to perform a self-test of the alignment detection equipment before alignment detection.

[0032] like Figure 1 As shown, the four primary coils are mounted on the ground-side equipment, specifically as follows: Figure 1 Transmitter 1, Transmitter 2, Transmitter 3, and Transmitter 4. The four secondary coils are mounted on the vehicle-mounted equipment, such as... Figure 2 As shown, Figure 2 Receiver 1, Receiver 2, Receiver 3, and Receiver 4. The coil positions of the vehicle-mounted equipment and the ground-based equipment correspond one-to-one. For example... Figure 3 , Figure 4As shown, in this embodiment, the external pile control terminal uses an external pile MCU, the ground control terminal uses a ground-based MCU, and the vehicle-mounted control terminal uses a vehicle-mounted MCU. The entire alignment detection system is connected as follows: the external pile MCU connects to the ground-based MCU via CAN communication for bidirectional communication. The ground-based MCU controls and connects to four inverters to send drive commands to the inverters. After receiving the drive commands, the inverters convert the input DC power to AC power. The AC terminals of the four inverters are connected one-to-one to the input terminals of the four primary coils in the transmitter resonant topology circuit to input electrical energy into the primary coils, which generate an alternating magnetic field of a fixed frequency. The four primary coils are respectively connected to the four secondary coils in the transmitter resonant topology circuit. The secondary coils couple with the magnetic field generated by the primary coils, inducing an electromotive force and outputting a voltage. The detection circuit collects the voltage output by the secondary coils through four interfaces. The detection circuit is connected to the vehicle-mounted MCU for sampling, so as to send the collected output voltage to the vehicle-mounted MCU. The vehicle-mounted MCU determines whether the output voltage is normal and gives a self-test result. It also sends the self-test result to the external pile MCU via WiFi so that the external pile MCU can determine whether to perform alignment detection.

[0033] In this embodiment, the resonant topology of both the transmitter and receiver resonant circuits can be any one of the following: SS, SP, PS, and PP topologies. The inverter in this embodiment includes a full-bridge topology (e.g.,...). Figure 5 (as shown) and half-bridge topology (such as) Figure 6 (As shown). In this embodiment, the drive command sent by the ground-side MCU to the inverter is a PWM wave.

[0034] In this system, signal reception is not a one-to-one correspondence; ground-based transmitting coil #1 is not necessarily detected by receiving coil #1. The coils are numbered at both the ground and receiving ends to identify problematic locations. When the ground-based transmitting coil receives an excitation voltage signal, all four coils at the receiving end can receive the signal. For example, if the secondary device deviates too much, causing receiving coil #4 to be near or above transmitting coil #2, then the signal induced by receiving coil #4 will originate from the excitation of transmitting coil #2.

[0035] However, during alignment detection, various factors can lead to repeated alignment attempts. Sometimes, problems within the circuit itself go undetected. For example, an open / short circuit in the primary-side excitation source circuit may prevent the generation of an excitation signal, or a short / open circuit in the secondary-side receiving circuit, or a damaged MCU, may prevent signal reception. In short, the source of the signal anomaly is either a problem at the ground end or the receiving end. Therefore, eliminating interference from the wireless charging device's own circuitry is crucial. This invention provides a self-testing method for alignment detection in wireless charging to eliminate interference from its own circuitry and improve alignment efficiency.

[0036] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0037] The following describes the steps of a self-test method for alignment detection in wireless charging, such as... Figure 7 As shown.

[0038] Step 1: The vehicle enters the charging area and stops. The auxiliary power supply of the wireless charging device is powered on.

[0039] Step 2: Alignment detection self-test starts.

[0040] The external pile body sends the "start alignment function" command to the ground MCU via CAN communication.

[0041] Step 3: The ground-based MCU begins sending drive commands.

[0042] Step 301: The ground-side MCU begins to send drive commands sequentially to the inverter topology (inverter) composed of full-bridge and half-bridge types, but the circuit is in an open circuit state at this time;

[0043] Step 302: The ground-side MCU sequentially sends out the activation switch K. X Driven by the current, the entire circuit is in a normal connection state, and the topology has the conditions for conversion from DC to AC. At this time, the primary coil L... p It can generate alternating voltage signals, and the primary coil is also called the transmitting coil.

[0044] Step 4: The vehicle-mounted MCU determines whether it can receive the voltage detection signals from each channel.

[0045] The secondary coil receives the alternating signal from the primary coil and generates a voltage signal; this secondary coil is also called the receiving coil. Under normal circumstances, the generated voltage signal enters the vehicle-side detection circuit and then the vehicle-side MCU. The vehicle-side detection circuit checks whether each voltage signal is normal. The detection circuit's judgment condition is: comparing the detected voltage magnitude with a set voltage threshold; if it is greater than the set voltage threshold, it is considered normal; otherwise, it is abnormal. The set voltage threshold varies depending on the vehicle model, specifically determined by the chassis height of the vehicle being charged. If the receiving coil does not detect a signal, this value remains constant.

[0046] Step 5: The on-board MCU determines the number of normal voltage signals.

[0047] The on-board MCU determines the number of normal detections based on the detected voltage signals and reports the result to the pile body. If the number of normal detections is ≤1, the alignment detection system cannot determine the position; if the number of normal detections is ≥2, the position determination can be completed.

[0048] The value of the normal voltage is related to the magnetic field distribution, coupling path r, core distribution, coil size d, current magnitude, and primary input excitation voltage (u). 激励 These factors are all related. Based on electromagnetic field theory, the voltage value obtained at the receiving end and the transmission distance have the following approximate relationship:

[0049]

[0050] The coefficient k is determined based on the magnetic field distribution, magnetic core distribution, and current magnitude, where 0 < k < 1.

[0051] Based on the experimentally obtained technical parameters: the primary side transmitting coil diameter is 9cm, the secondary side receiving coil diameter is 6cm, the primary side excitation power supply is 12V, the coupling path is 20cm, and the effective voltage of the secondary side receiving coil is approximately 1.2V.

[0052] Step 6: Complete the alignment self-test / position detection results.

[0053] If the system does not have the conditions to perform alignment detection, the alignment function self-test is completed, and the pile body will receive a fault command from the vehicle-mounted MCU. If the system has the conditions to perform alignment detection, the vehicle-mounted MCU will report the position determination result to the pile body, and the alignment detection ends. After the pile body receives the fault information that alignment detection is not possible or the position detection result, the pile body will send a "close alignment function" command to the ground-based MCU. After receiving the command, the ground-based MCU will shut down all drive signals, and the alignment detection process will end.

[0054] Before alignment detection, this invention first sends a drive command to the alignment detection device, then collects the output voltage from the output terminal, and determines whether the output voltage exceeds a set voltage threshold. Based on the number of output voltages exceeding the set voltage threshold, it determines whether alignment detection can be performed. This achieves a self-test function before alignment detection. Adding a self-test function before alignment detection allows for early prediction of the system's operating status, early reporting of faults, and improved reliability of the alignment detection device. It also facilitates early prediction of device status or timely adoption of backup plans. On the other hand, performing alignment function testing only after confirming that the device logic is normal following the self-test facilitates rapid alignment and improves the alignment success rate.

[0055] An embodiment of an alignment detection self-test method for wireless charging:

[0056] An embodiment of the alignment detection self-test method for wireless charging according to the present invention includes the following steps:

[0057] 1) Send N drive commands to the inverter to stimulate the alignment detection device to generate N voltages, where N ≥ 1; collect the generated N output voltages.

[0058] 2) If the number of output voltage channels collected is greater than or equal to 2, then determine the relationship between the output voltage and the set voltage threshold.

[0059] If at most one of the acquired output voltages is greater than or equal to the set voltage threshold, a self-test result indicating that alignment detection is unsuccessful is output; if at least two of the acquired output voltages are greater than or equal to the set voltage threshold, a self-test result indicating that alignment detection is normal is output. This method is consistent with an alignment detection self-test method for wireless charging in an embodiment of an alignment detection system, achieving the same effect, and therefore will not be described in detail here.

Claims

1. A self-testing method for alignment detection in wireless charging, characterized in that: Includes the following steps: 1) Send one drive command to each of the N inverters in the alignment detection device to induce N voltages in the N secondary coils of the alignment detection device, where N ≥ 1; the N inverters are located between the DC power supply and the N primary coils, and the AC terminals of the N inverters are connected to the N primary coils one by one. N primary coils are inductively connected to N secondary coils; 2) Collect N output voltages generated by N primary coils and determine the relationship between the output voltage and the set voltage threshold: If at most one of the collected output voltages is greater than or equal to the set voltage threshold, output a self-test result indicating that the alignment detection cannot be performed; if at least two of the collected output voltages are greater than or equal to the set voltage threshold, output a self-test result indicating that the alignment detection is normal.

2. The alignment detection self-test method for wireless charging according to claim 1, characterized in that: In step 2), the output voltage information corresponding to the output voltage that is less than the set voltage threshold also needs to be output.

3. The alignment detection self-test method for wireless charging according to claim 1, characterized in that: In step 2), if at most one of the acquired output voltages is greater than or equal to the set voltage threshold, a stop alignment detection command must be sent; if at least two of the acquired output voltages are greater than or equal to the set voltage threshold, an alignment detection command must be sent.

4. The alignment detection self-test method for wireless charging according to claim 1, characterized in that: The voltage threshold value is determined by the following formula: Where k is a coefficient obtained based on the magnetic field distribution, core distribution, and current magnitude, 0 < k < 1, r is the coupling path, d is the secondary coil size, and u 激励 This is the primary input excitation voltage.

5. The alignment detection self-test method for wireless charging according to claim 1, characterized in that: N＝4。 6. The alignment detection self-test method for wireless charging according to any one of claims 1 to 5, characterized in that: The driving command is a PWM wave.

7. An alignment detection system, characterized in that: The system includes a control terminal and an alignment detection device. The alignment detection device includes N inverters, N primary windings, N secondary windings, and a detection circuit. The AC terminals of the N inverters are connected one-to-one with the N primary windings. The N primary windings are inductively connected to the N secondary windings. The detection circuit is used to collect the N output voltages generated and output by the N secondary windings in the alignment detection device. The control terminal controls and connects to each inverter, and the sampling terminal connects to the detection circuit. The control terminal is used to: send one drive command to each of the N inverters to stimulate the N secondary coils in the alignment detection device to generate N voltages, where N ≥ 1, and receive the N output voltages collected by the detection circuit; It also determines the relationship between the output voltage and the set voltage threshold. If at most one of the acquired output voltages is greater than or equal to the set voltage threshold, it outputs a self-test result indicating that the alignment detection cannot be performed. If at least two of the acquired output voltages are greater than or equal to the set voltage threshold, it outputs a self-test result indicating that the alignment detection is normal.

8. The alignment detection system according to claim 7, characterized in that: The control terminal includes: a ground control terminal, a vehicle-mounted control terminal, and an external pile body control terminal; the ground control terminal controls and connects to each inverter, and is used to send one drive command to each inverter; the vehicle-mounted control terminal is connected to a sampling and detection circuit, and is used to acquire N output voltages collected by the detection circuit, determine the relationship between the output voltage and the set voltage threshold, and output self-test results; the external pile body control terminal controls and connects to the ground control terminal and the vehicle-mounted control terminal, and is used to send control commands to the ground control terminal and to receive self-test results.

9. The alignment detection system according to claim 7, characterized in that: N＝4。 10. The alignment detection system according to claim 8, characterized in that: The external pile control terminal also needs to send the following information based on the self-test results: if the self-test result is normal alignment detection, then send an alignment detection command to the ground control terminal; if the self-test result is that alignment detection is not possible, then send a stop alignment detection command to the ground control terminal.

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