A high-power wireless charging vehicle terminal protection system and method

Abstract

The application discloses a kind of high-power wireless charging vehicle terminal protection system and method, the system includes backup power supply, backup power supply input end is powered from EMI filter circuit rear end, the output of backup power supply is connected with the input of low-voltage power conversion circuit, when vehicle terminal power supply appears abnormal condition, whole car low-voltage battery is disconnected with low-voltage power conversion circuit, backup power supply starts immediately, keep low-voltage power conversion circuit normal work under abnormal condition, and supply power for vehicle terminal by low-voltage power conversion circuit.The high-power wireless charging vehicle terminal protection system and method disclosed by the application greatly improve the reliability, safety and protection real-time of the product by increasing backup power supply, and the overall structure is reasonable, low in cost, and suitable for industrial popularization and use.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of wireless charging, and particularly relates to a high-power wireless charging vehicle-end protection system and method. BACKGROUND

[0002] With the rapid development of the electric, intelligent, networked and 5G industries of the automobile industry, wireless charging technology has become one of the hotspots of the automobile industry. Since the wireless charging system is one of the components of the whole vehicle, the charging safety and reliability of the component are extremely important in the case of abnormality of each working condition of the whole vehicle.

[0003] The vehicle-end of the wireless charging system of the electric vehicle is a device directly installed on the vehicle end, and directly connected with the power battery of the electric vehicle for energy transmission during work. The protection system of the vehicle-end of the electric vehicle has always been a very important link in the wireless charging system, and is required to have very good real-time performance and system safety. However, the existing protection system of the vehicle-end has the following defects: when the output relay of the vehicle-end abnormally disconnects and the low-voltage storage battery of the whole vehicle has no output voltage to the input end of the low-voltage power conversion circuit, this will inevitably cause the failure of the vehicle-end product (overvoltage breakdown of full-bridge rectifier diode or MOS tube). Therefore, in view of the above problems, it is necessary to propose a further solution. SUMMARY

[0004] In order to solve the technical problems existing in the prior art, the purpose of the present application is to provide a high-power wireless charging vehicle-end protection system and method.

[0005] In order to achieve the above purpose and achieve the above technical effects, the technical solution adopted by the present application is:

[0006] A high-power wireless charging vehicle-end protection system, comprising a backup power supply, the input end of the backup power supply taking power from the output end of an EMI filter circuit, and the output end of the backup power supply being connected with the input end of a low-voltage power conversion circuit. When abnormality occurs in the power supply of the vehicle-end, the low-voltage storage battery of the whole vehicle is disconnected from the low-voltage power conversion circuit, the backup power supply is started immediately, the low-voltage power conversion circuit is kept working normally under abnormal conditions, and the low-voltage power conversion circuit supplies power to the vehicle-end.

[0007] Further, the system further comprises a wire coil Ls, a compensation network, a controllable rectifier, a filter, an EMI filter circuit, a pre-charge circuit and a control part, the wire coil Ls, the compensation network, the controllable rectifier, the filter, the EMI filter circuit and the pre-charge circuit are sequentially electrically connected; the wire coil Ls induces alternating current in the alternating magnetic field, realizing the conversion of magnetic energy into electric energy; the compensation network outputs the alternating current after compensation to the controllable rectifier; the controllable rectifier controls the conduction angle of its MOS tubes Q1 and Q2 to realize the transmission of different power levels and improve the efficiency of the whole system; the filter is used to filter out the ripple in the output voltage of the controllable rectifier, and convert the large-pulsating direct current into direct current with smaller ripple components; the pre-charge circuit is used to suppress the inrush current during the attraction of the high-voltage power battery; the control part is connected with a low-voltage power conversion circuit, and the low-voltage power conversion circuit supplies power to the control part.

[0008] Further, the EMI filter circuit comprises a two-stage EMI filter circuit, and the output voltage range is 180VDC-900VDC.

[0009] Further, diodes are respectively connected in series on the output positive poles of the backup power supply and the vehicle low-voltage storage battery, for preventing voltage backflow.

[0010] Further, the backup power supply topology adopts Flyback, the input voltage range is 180VDC-900VDC, single-output, and the output voltage is 8.5V and the output power is 10W.

[0011] Further, the backup power supply comprises a MOS tube Q3.

[0012] The drain-source voltage of the MOS tube Q3 when it is turned off is:

[0013] Q3Vdsoff=Vinmax+n·Vo+Vleg

[0014] The average current flowing through the MOS tube Q3 is:

[0015]

[0016] wherein Vinmax represents the maximum voltage between OUT+ and OUT-; Vinmin represents the minimum voltage between OUT+ and OUT-; Dmax represents the maximum duty cycle, not greater than 0.5; n represents the transformation ratio of the backup power supply transformer, Vo represents the output voltage; Vleg represents the peak voltage when the MOS tube is turned off, generally taking 10%-15% of the rated voltage; Po represents the output power; η represents the efficiency;

[0017] The device selection of Q3 is obtained according to the calculation formula of Q3Vdsoff / Q3Iavg.

[0018] Furthermore, the backup power supply uses a transformer for electrical isolation between the input and output.

[0019] Furthermore, the relationship between the backup power supply and the vehicle's low-voltage battery is as follows: the output voltage of the vehicle's low-voltage battery determines whether the backup power supply output is activated to apply load.

[0020] This invention also discloses a method for protecting a high-power wireless charging vehicle-mounted terminal, which provides protection based on the high-power wireless charging vehicle-mounted terminal protection system described above. The method includes the following steps:

[0021] When an abnormal situation occurs during the charging process of the vehicle-mounted product, the low-voltage battery of the vehicle is disconnected from the low-voltage power conversion circuit, and the backup power supply is immediately activated to maintain the normal operation of the low-voltage power conversion circuit under abnormal conditions and to supply power to the vehicle-mounted product through the low-voltage power conversion circuit. At the same time, the vehicle-mounted product detects the output overvoltage fault and immediately drives the MOSFETs Q1 / Q2 high, short-circuits the controllable rectifier, and has no output. The vehicle-mounted product notifies the ground equipment of the fault shutdown through wireless communication technology.

[0022] Furthermore, the two-stage EMI filter circuit has an output voltage at the end, with an output voltage range of 180VDC-900VDC. When the backup power supply starts working, the output voltage is 8.5V.

[0023] If the output voltage at the end of the two-stage EMI filter circuit is less than 150VDC or greater than 920VDC, the backup power supply will not work and there will be no output voltage.

[0024] When the backup power supply starts working, it outputs 8.5V and is in a constant voltage state under no-load conditions. Whether it needs to be under load is determined by the vehicle's low-voltage battery.

[0025] The output voltage of the vehicle's low-voltage battery is >8.9V, and the input power supply of the low-voltage power conversion circuit is provided by the vehicle's low-voltage battery.

[0026] The output voltage of the vehicle's low-voltage battery is 8.1V-8.9V, and the input power supply of the low-voltage power conversion circuit is provided by the vehicle's low-voltage battery and the backup power supply.

[0027] The output voltage of the vehicle's low-voltage battery is <8.1V, and the input power supply for the low-voltage power conversion circuit is provided by the backup power supply.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] This invention discloses a high-power wireless charging vehicle-mounted protection system and method. The system includes a backup power supply. The input of the backup power supply draws power from the rear end or output of an EMI filter circuit. The output of the backup power supply is connected to the input of a low-voltage power conversion circuit. When an abnormality occurs in the vehicle-mounted power supply, the vehicle's low-voltage battery is disconnected from the low-voltage power conversion circuit, and the backup power supply immediately starts, maintaining the normal operation of the low-voltage power conversion circuit under abnormal conditions and supplying power to the vehicle-mounted terminal through the low-voltage power conversion circuit. The high-power wireless charging vehicle-mounted protection system and method disclosed in this invention significantly improves the reliability, safety, and real-time protection capabilities of the product by adding a backup power supply. Furthermore, the overall structure is reasonable, the cost is low, and it is suitable for industrial-scale application. Attached Figure Description

[0030] Fig. 1 This is a schematic diagram of the structure of the present invention;

[0031] Fig. 2 This is a flowchart illustrating the operation of the backup power supply of the present invention.

[0032] Fig. 3 This is a simulation diagram of the output voltage of the present invention changing with the load. Detailed Implementation

[0033] The present invention will now be described in detail so that its advantages and features can be more easily understood by those skilled in the art, thereby providing a clearer and more explicit definition of the scope of protection of the present invention.

[0034] The following provides a brief overview of one or more aspects to offer a basic understanding of them. This overview is not an exhaustive summary of all conceived aspects, nor is it intended to identify key or decisive elements of all aspects, nor to define the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form to prepare for the more detailed descriptions that follow.

[0035] like Figs. 1-3As shown, a high-power wireless charging vehicle-mounted protection system includes a backup power supply, a coil Ls (receiving coil), a compensation network, a controllable rectifier, a filter, an EMI filter circuit, a pre-charging circuit, a control section, and a low-voltage power conversion circuit. The input of the backup power supply is drawn from the rear end or output of the EMI filter circuit (mainly referring to a two-stage EMI filter circuit). The output of the backup power supply is connected to the input of the low-voltage power conversion circuit. The output voltage range of the EMI filter circuit is 180VDC-900VDC, and the backup power supply can operate normally within this voltage range. Diodes are connected in series on the positive output terminals of the backup power supply and the vehicle's low-voltage battery to prevent voltage reverse flow. During power transmission, if the output relay of the vehicle-mounted terminal disconnects due to abnormal conditions and the low-voltage power conversion circuit has no input power, the transmission delay is 0 seconds to switch and start the backup power supply, thereby protecting the vehicle-mounted product. The coil Ls induces alternating current in an alternating magnetic field, realizing the conversion of magnetic energy into electrical energy. The compensation network compensates for the alternating current and outputs it to a controllable rectifier. The ripple in the output voltage of the controllable rectifier is filtered out, and the large-pulsation DC current is converted into DC current with smaller ripple components. Differential mode interference signals and common mode interference signals in the two-stage EMI filtering circuit are used to prevent the high frequency generated by the power switching circuit from interfering with other equipment or other equipment to the product. The control part mainly realizes sampling, protection, communication and driving functions. The low-voltage power conversion circuit mainly generates different output voltages to power the control part.

[0036] The compensation network adopts an LCC topology to match the secondary impedance, so that the secondary side is in a resonant state.

[0037] The controllable rectification adopts a full-bridge configuration, with a diode as the upper transistor and MOSFETs Q1 and Q2 as the lower transistors. Different power levels can be achieved by controlling the different conduction angles of the two transistors.

[0038] The pre-charge circuit consists of a relay, a pre-charge resistor, and a diode. When the high-voltage power battery of the vehicle is engaged, the pre-charge resistor and diode suppress the surge current. At the same time, the diode plays the role of preventing reverse connection and protecting the pre-charge resistor.

[0039] Vehicle-mounted protection systems without backup power have significant drawbacks, exposing them to the risk of failure. This is because, without backup power, during charging, abnormal situations (such as an output relay disconnecting, causing no input power to the no-load / low-voltage power conversion circuit, resulting in no protection system on the vehicle) can lead to problems. Since communication between the vehicle and ground relies on Wi-Fi, which has a timeout of 3-5 seconds, the energy transmitter / vehicle-mounted unit remains in a charging state during this period. This poses a risk of overvoltage damage to diodes and MOSFETs (according to U=I*R). Due to the inherent characteristics of the LCC topology (the vehicle-mounted unit has constant current characteristics but no constant voltage characteristics), the formula for the output current of the vehicle-mounted controllable rectifier front-end is as follows:

[0040]

[0041] Where M represents mutual inductance; UAB represents the output voltage of the energy conversion terminal inverter; ω represents the angular frequency; LF1 represents the inductance of the energy conversion terminal inverter; and LF2 represents the rectifier inductance of the energy receiving terminal (i.e., the vehicle-mounted terminal).

[0042] This invention improves the safety and reliability of vehicle-mounted products by adding a backup power supply to the control unit.

[0043] The backup power supply topology of this invention adopts Flyback, with a designed input voltage range of 180VDC-900VDC, single output, output voltage of 8.5V, and output power of 10W.

[0044] Selection principles for the key component of the backup power supply, MOSFET Q3:

[0045] The drain-source voltage of MOSFET Q3 when it is turned off is Q3Vdsoff = Vinmax + n·Vo + Vleg. The average current flowing through MOSFET Q3 is as follows:

[0046]

[0047] Where Vinmax represents the maximum voltage between OUT+ and OUT-; Vinmin represents the minimum voltage between OUT+ and OUT-; Dmax represents the maximum duty cycle, generally not greater than 0.5; and n represents the turns ratio of the standby power transformer. Vo represents the output voltage; Vleg represents the peak voltage when the MOSFET is turned off, which is generally 10%-15% of the rated voltage; Po represents the output power; η represents the efficiency.

[0048] The selection of components for Q3 can be obtained using the formula Q3Vdsoff / Q3Iavg.

[0049] The backup power supply uses a transformer for electrical isolation between input and output. The relationship between the backup power supply and the vehicle's low-voltage battery is as follows: the output voltage of the vehicle's low-voltage battery determines whether the backup power supply should initiate load control. Fig. 3 As shown, diodes are connected in series on the positive output terminals of both the backup power supply and the vehicle's low-voltage battery to prevent reverse voltage flow. During the charging process, the on-board unit is prone to abnormal situations, such as: the wiring harness from the vehicle's low-voltage battery to the low-voltage power conversion circuit becoming detached, aged, or having poor contact; or human error causing the input to the low-voltage power conversion circuit to disconnect, resulting in the output relay disconnecting and the low-voltage power conversion circuit having no input. When these abnormal situations occur, the vehicle's low-voltage battery is disconnected from the low-voltage power conversion circuit, and the backup power supply will start working with zero delay, maintaining the normal operation of the low-voltage power conversion circuit under abnormal conditions. Abnormal situations can lead to output overvoltage. The on-board unit will detect this output overvoltage fault and immediately set Q1 / Q2 high, short-circuiting the controllable rectifier and causing no output. Simultaneously, the on-board unit will notify the ground equipment of the fault shutdown via wireless communication (WIFI).

[0050] A method for protecting the vehicle-mounted terminal of a high-power wireless charging system includes the following steps:

[0051] When an abnormality occurs during charging of the vehicle-mounted product, the vehicle's low-voltage battery is disconnected from the low-voltage power conversion circuit, and the backup power supply immediately starts, maintaining the normal operation of the low-voltage power conversion circuit under abnormal conditions and supplying power to the vehicle-mounted unit through the low-voltage power conversion circuit. Simultaneously, the vehicle-mounted unit detects an output overvoltage fault and immediately drives MOSFETs Q1 / Q2 high, short-circuiting the controlled rectifier, resulting in no output. The vehicle-mounted unit then notifies the ground-based equipment of the fault shutdown via wireless communication technology. The backup power supply's operating steps include:

[0052] The two-stage EMI filter circuit has an output voltage at the end, with an output voltage range of 180VDC-900VDC. When the backup power supply starts working, the output voltage is 8.5V.

[0053] If the output voltage at the end of the two-stage EMI filter circuit is less than 150VDC or greater than 920VDC, the backup power supply will not work and there will be no output voltage.

[0054] When the backup power supply starts working, it outputs 8.5V and is in a constant voltage state under no-load conditions. Whether it needs to be under load is determined by the vehicle's low-voltage battery.

[0055] The output voltage of the vehicle's low-voltage battery is >8.9V, and the input power supply of the low-voltage power conversion circuit is provided by the vehicle's low-voltage battery.

[0056] The output voltage of the vehicle's low-voltage battery is between 8.1V and 8.9V. The input power supply of the low-voltage power conversion circuit is provided by the vehicle's low-voltage battery and the backup power supply.

[0057] The output voltage of the vehicle's low-voltage battery is <8.1V, and the input power supply for the low-voltage power conversion circuit is provided by the backup power supply.

[0058] Any parts or structures not specifically described in this invention can be made using existing technologies or products, and will not be elaborated upon here.

[0059] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A high-power wireless charging vehicle-end protection system, characterized in that, The backup power supply includes an input end connected to the output end of the EMI filter circuit and an output end connected to the input end of the low-voltage power conversion circuit, and when an abnormal situation occurs in the vehicle-mounted end power supply, the vehicle low-voltage storage battery is disconnected from the low-voltage power conversion circuit, and the backup power supply is started immediately to keep the low-voltage power conversion circuit working normally in the abnormal situation and supply power to the vehicle-mounted end through the low-voltage power conversion circuit. The backup power supply includes a MOS tube Q3. The drain-source voltage of the MOS tube Q3 when the MOS tube Q3 is turned off is: The average current flowing through the MOS tube Q3 is: Wherein, Vinmax represents the maximum voltage between OUT+ and OUT-; Vinmin represents the minimum voltage between OUT+ and OUT-; Dmax represents the maximum duty ratio, not greater than 0.5; n represents the transformation ratio of the standby power transformer, ; Vo represents the output voltage; Vleg represents the peak voltage when the mos tube is off, generally the value is 10%-15% of the rated voltage; Po represents the output power; η represents the efficiency; The device selection of the MOS tube Q3 is obtained according to the calculation formula of Q3Vdsoff / Q3Iavg.

2. The protection system for high-power wireless charging vehicle side according to claim 1, characterized in that, The system further includes a wire coil Ls, a compensation network, controllable rectification, filtering, an EMI filter circuit, a pre-charging circuit and a control part, and the wire coil Ls, the compensation network, the controllable rectification, the filtering, the EMI filter circuit and the pre-charging circuit are sequentially electrically connected; the wire coil Ls induces alternating current in the alternating magnetic field to realize the conversion of magnetic energy into electrical energy; the compensation network compensates the alternating current and then outputs the alternating current to the controllable rectification; the controllable rectification controls the conduction angle of MOS tubes Q1 and Q2 to realize the transmission of different power levels and improve the efficiency of the whole system; the filtering is used to filter out the ripple in the output voltage of the controllable rectification and convert the large-pulsating direct current into direct current with smaller ripple components; the pre-charging circuit is used to suppress the inrush current during the attraction of the vehicle high-voltage power battery; and the control part is connected to the low-voltage power conversion circuit and is supplied with power through the low-voltage power conversion circuit.

3. The protection system for a high-power wireless charging vehicle-mounted terminal according to claim 1 or 2, characterized in that, The EMI filter circuit includes a two-stage EMI filter circuit, and the output voltage range is 180VDC-900VDC.

4. The system of claim 1, wherein the system is a high power wireless charging vehicle mounted system. Diodes are respectively connected in series with the output positive poles of the backup power supply and the vehicle low-voltage storage battery to prevent voltage backflow.

5. The system of claim 1, wherein the system is a high power wireless charging vehicle mounted system. The backup power supply topology adopts Flyback, the input voltage range is 180VDC-900VDC, single output, the output voltage is 8.5V, and the output power is 10W.

6. The system of claim 1, wherein the system is a high power wireless charging vehicle mounted system. The backup power supply adopts a transformer as the electrical isolation between the input and the output.

7. The system of claim 1, wherein the system is a high power wireless charging vehicle mounted system. The relationship between the backup power supply and the vehicle low-voltage storage battery is that whether the backup power supply output starts to pull the load is determined according to the output voltage value of the vehicle low-voltage storage battery.

8. A method for protecting a vehicle-mounted end of a high-power wireless charging, characterized in that, A large-power wireless charging vehicle-mounted end protection system according to any one of claims 1-7 is used for protection, and the method includes the following steps: When an abnormal situation occurs in the charging process of the vehicle-mounted end product, the vehicle low-voltage storage battery is disconnected from the low-voltage power conversion circuit, the backup power supply is started immediately, the low-voltage power conversion circuit keeps working normally in the abnormal situation, and the low-voltage power conversion circuit supplies power to the vehicle-mounted end; at the same time, the vehicle-mounted end detects an output overvoltage fault and immediately sets the MOS tube Q1 / Q2 drive high, the controllable rectification is short-circuited, there is no output, and the vehicle-mounted end informs the ground end equipment of the fault shutdown through wireless communication technology.

9. The method of claim 8, wherein the method further comprises: The two-stage EMI filter circuit has an output voltage, the output voltage range is 180VDC-900VDC, the backup power supply starts to work, and the output voltage is 8.5V. The output voltage of the two-stage EMI filter circuit is less than 150 VDC or greater than 920 VDC, the backup power supply is not working, and there is no output voltage; The backup power supply is working, there is an output voltage of 8.5 V, and the no-load constant voltage state is determined by the vehicle low-voltage storage battery whether to be loaded; The output voltage of the vehicle low-voltage storage battery is greater than 8.9 V, and the input power supply of the low-voltage power conversion circuit is provided by the vehicle low-voltage storage battery; The output voltage of the vehicle low-voltage storage battery is 8.1 V-8.9 V, and the input power supply of the low-voltage power conversion circuit is provided by the vehicle low-voltage storage battery and the backup power supply; The output voltage of the vehicle low-voltage storage battery is less than 8.1 V, and the input power supply of the low-voltage power conversion circuit is provided by the backup power supply.

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