Dynamic wireless charging coil positioning system and method for segmented electric vehicles

Abstract

The present invention discloses a system and method for positioning a dynamic wireless charging coil for a segmented electric vehicle, and belongs to the field of wireless power transmission technology. The system includes a power transmission module and a positioning module. The power transmission module includes a transmitting end, a segmented coupling mechanism, and a receiving end. The transmitting end generates high-frequency alternating current and injects it into the transmitting coil. The power is transmitted to the load end through the magnetic coupling of the coupling mechanism to complete the power transmission. A positioning module is also provided at the transmitting end, which can perform frequency scanning on the power transmission path by controlling the frequency of the inverter power supply, identify the coupling mutual inductance between the transmitting and receiving ends, and then realize the position identification of the receiving coil. The present invention can provide real-time positioning for a dynamic wireless system under the movement of the receiving end, and can realize the function of charging the electric vehicle while walking by controlling the switching of the transmitting coil switch.

Description

Technical Field

[0001] The present invention belongs to the technical field of wireless power transmission, and in particular relates to a dynamic wireless charging coil positioning system and method suitable for segmented electric vehicles. Background Art

[0002] High-efficiency, low-emission electric vehicles are replacing traditional fuel vehicles, an inevitable industry trend. However, their development is hampered by stationary charging and high battery costs. Electric Vehicle Dynamic Wireless Charging (EV-DWC) technology enables a new "charging while driving" energy replenishment method, effectively reducing vehicle battery costs and increasing driving range.

[0003] The rapid, high-precision positioning of short-segment EV-DWC systems has become a research hotspot in this field. To improve the charging efficiency of short-segment dynamic wireless charging systems, precise vehicle positioning is required to enable real-time switching of the system's power supply. Rapid response is particularly crucial for high-speed electric vehicles. However, current dynamic positioning technologies for electric vehicles rely on two-way communication between the transmitter and the vehicle, resulting in numerous positioning control steps and long response times. Therefore, it is necessary to develop a positioning method that can identify the vehicle's position through unilateral data measurement. Summary of the Invention

[0004] In order to solve the problems existing in the prior art, the present invention proposes a dynamic wireless charging coil positioning system and method suitable for segmented electric vehicles, which can realize real-time power supply for electric vehicles while driving on the road.

[0005] Technical solution: In order to achieve the above purpose, the technical solution of the present invention is:

[0006] A dynamic wireless charging coil positioning system for a segmented electric vehicle comprises a power transmission module and a positioning module; the power transmission module comprises a power transmitting end, a segmented magnetic coupling mechanism and a power receiving end; the power transmitting end comprises an inverter power supply and a transmitting end compensation circuit; the segmented magnetic coupling mechanism comprises a transmitting coil and a receiving coil laid out at continuous fixed intervals, each transmitting coil being connected in series with the transmitting end compensation circuit; the power receiving end comprises a receiving end compensation circuit, a rectifier circuit and an electric vehicle on-board battery load, the input end of the receiving end compensation circuit being connected to the output end of the receiving coil, the output end of the receiving end compensation circuit being connected to the input end of the rectifier circuit, and the output end of the rectifier circuit being connected to the battery load; the positioning module comprises a sampling module, a phase comparator and a frequency driving module, the sampling module collects the output voltage and output current of the inverter power supply in real time, and sends the source end signal to the phase comparator, the phase comparator controls the frequency driving module through the collected source end signal to control the output frequency of the inverter power supply.

[0007] Furthermore, the transmitting coil and the receiving coil of the segmented magnetic coupling mechanism are the same, and the parasitic resistance of the transmitting coil R 1-i The same as the parasitic resistance R2 of the receiving coil, the transmitting coil is laid continuously under the road surface, and the receiving coil is installed under the chassis of the electric vehicle.

[0008] Furthermore, the transmitter compensation circuit includes a resonant capacitor C 1-i With the transmitting coil L 1-i The receiving end compensation circuit includes a resonant capacitor C2 connected in series with the receiving coil L2 to form a series resonance. If the resonant operating frequency of the energy transfer circuit is ω0, then the formula (1) is satisfied:

[0009]

[0010] Where, L 1-i is the self-inductance of the i-th transmitting coil, C 1-i is the series compensation capacitor of the i-th transmitting coil, L2 is the self-inductance of the receiving coil, and C2 is the series compensation capacitor of the receiving coil.

[0011] Furthermore, the inverter power supply is a voltage-type full-bridge inverter power supply, including four SiC-MOSFET switching tubes and four uncontrolled diodes, and the SiC-MOSFET switching tubes and the uncontrolled diodes are connected in reverse parallel.

[0012] Furthermore, the rectifier circuit is a single-phase bridge uncontrolled rectifier circuit, including four uncontrollable diodes and a voltage-stabilizing capacitor.

[0013] A coil positioning method for dynamic wireless charging of an electric vehicle using the above-mentioned segmented electric vehicle dynamic wireless charging coil positioning system comprises the following steps:

[0014] (1) Control the operating frequency of the inverter power supply to perform frequency scanning between 0 and ω0, and the sampling module collects the output voltage of the inverter power supply in real time and output current

[0015] (2) Phase comparator real-time comparison and When the phase difference between the two is 0, the working frequency ω is collected at this time. k , setting the electrical parameters of the transmitting coil and the receiving coil to be the same, then:

[0016]

[0017] Where L2 is the self-inductance of the receiving coil, L is the simplified self-inductance of the transmitting and receiving coils, and C 1-i is the series compensation capacitor of the i-th transmitting coil, C2 is the capacitor of the receiving end compensation circuit, and C is the compensation capacitor of the simplified transmitting and receiving coils.

[0018] (3) Measure the relationship between the coupling coefficient k and the relative position of the transmitting coil and the receiving coil through simulation or experiment, that is, k(x);

[0019] (4) Calculate the coupling coefficient k between the transmitting coil and the receiving coil at this time c :

[0020]

[0021] Where R L is the load equivalent resistance, and R2 is the parasitic resistance of the receiving coil.

[0022] (5) The position of the receiving coil can be obtained in real time by substituting kc into the k(x) curve. When the receiving coil is located above the transmitting coil, the inverter power supply output frequency is controlled to ω0, and the receiving end is powered in real time in the resonant state.

[0023] Beneficial effects of the present invention:

[0024] Aiming at the technical background of high-precision positioning of dynamic wireless charging systems for electric vehicles, the present invention provides a coil positioning system suitable for dynamic wireless charging of electric vehicles. By obtaining the output electrical parameters of the source end through a frequency scanning method, the position of the receiving end relative to the transmitting coil can be obtained in real time. This solves the problem that dynamic wireless charging positioning of electric vehicles requires two-end communication, and provides new ideas for the application of wireless power transmission technology in electric vehicles. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Schematic diagram of the coil positioning system for dynamic wireless charging of electric vehicles according to the present invention;

[0026] Figure 2 It is a circuit diagram of the power transmission path;

[0027] Figure 3 It is the equivalent circuit diagram of the load-end transformation module. DETAILED DESCRIPTION

[0028] The design of the magnetic coupling mechanism provided in this application is described in detail below with reference to the accompanying drawings.

[0029] like Figure 1 As shown, a coil positioning system suitable for dynamic wireless charging of electric vehicles, the power transmission module includes a power transmitting end, a segmented magnetic coupling mechanism and a power receiving end; the power transmitting end includes a high-frequency inverter power supply and a compensation circuit; the segmented magnetic coupling mechanism includes a transmitting coil and a receiving coil laid out at continuous fixed intervals, each transmitting coil is connected in series with a compensation circuit, and its input end is connected to the output end of the inverter power supply; the power receiving end includes a rectifier circuit and an on-board battery load of the electric vehicle, the input end of the rectifier circuit is connected to the output end of the receiving coil, and the output end of the rectifier circuit is connected to the battery load; the positioning module includes a current sampling module, a phase comparator and a frequency driving module, the current sampling module collects the output voltage and output current of the inverter power supply in real time, and sends the source end signal to the phase comparator, the phase comparator controls the frequency driving module through the collected signal to control the output frequency of the inverter power supply.

[0030] like Figure 2 As shown, The output voltage of the high-frequency inverter power supply can be changed through the control circuit to change the switching frequency ω of the switching device. M is the coupling mutual inductance between the transmitting coil and the receiving coil, thereby changing the output frequency of the inverter. L1 is the self-inductance of a single transmitting coil, R1 is the parasitic resistance of the transmitting coil, C1 is the capacitance of the transmitting end compensation circuit, L2 is the self-inductance of the receiving coil, R2 is the parasitic resistance of the receiving coil, and C2 is the capacitance of the receiving end compensation circuit. is the inverter output current, is the receiving coil current, R L is the equivalent resistance at the load end, S1~S4 are MOSFET switches of the inverter power supply, D1~D4 are diodes connected in parallel with the switches, V D is the DC voltage of the inverter input.

[0031] The load end circuit is as follows Figure 3 As shown, its main function is to convert high-frequency AC power into DC power to charge the vehicle-side battery load in real time.

[0032] The positioning principle and method of the coil positioning system suitable for dynamic wireless charging of electric vehicles are as follows:

[0033] Assume X1=ωL1-1 / ωC1,X2=ωL1-1 / ωC1, according to Figure 2 Write the KVL equation of the circuit:

[0034]

[0035] Then the input impedance of the system is Z in It can be expressed as:

[0036]

[0037] Assume X = ωL-1 / ωC, and let the imaginary part of Zin be 0. Under overcoupling, the system has three resonance points:

[0038]

[0039] When the system operating frequency is ω +,- When , the input impedance is:

[0040]

[0041] It can be seen that when ω=ω +,- When , the system input impedance is completely determined by the system parasitic parameters and the load resistance. Substitute equation (7) into equation (6) and solve it inversely to obtain the calculated value of the coupling coefficient k c :

[0042]

[0043] By comparing the relationship k(x) between the coupling coefficient k of the receiving coil and the relative position of the transmitting coil, the current position of the receiving coil can be identified. When the receiving coil is positioned above the transmitting coil, the output frequency of the inverter power supply is adjusted to ω0, realizing real-time power replenishment to the receiving end of the electric vehicle.

[0044] The above is only the technical solution of the present invention and cannot be used to limit the scope of protection of the present invention. For those skilled in the art, without departing from the principle of the present invention, the present invention can still be modified and replaced with equivalents, which all fall within the scope of protection of the present invention.

Claims

1. A coil positioning method suitable for segmented electric vehicle dynamic wireless charging, the method being suitable for a segmented electric vehicle dynamic wireless charging coil positioning system, the segmented electric vehicle dynamic wireless charging coil positioning system comprising a power transmission module and a positioning module; the power transmission module comprising a power transmitter, a segmented magnetic coupling mechanism, and a power receiver; the power transmitter comprising an inverter power supply and a transmitter compensation circuit; the segmented magnetic coupling mechanism comprising a transmitting coil and a receiving coil arranged at fixed intervals, each transmitting coil being connected in series with a transmitting compensation circuit; the power receiver comprising a receiving compensation circuit, a rectifier circuit, and an electric vehicle onboard battery load, the input of the receiving compensation circuit being connected to the output of the receiving coil, the output of the receiving compensation circuit being connected to the input of the rectifier circuit, and the output of the rectifier circuit being connected to the battery load; The positioning module includes a sampling module, a phase comparator and a frequency driving module. The sampling module collects the output voltage and output current of the inverter power supply in real time and sends the source end signal to the phase comparator. The phase comparator controls the frequency driving module through the collected source end signal to control the output frequency of the inverter power supply; The transmitting coil and the receiving coil of the segmented magnetic coupling mechanism are the same, and the parasitic resistance of the transmitting coil R 1-i The parasitic resistance R2 of the receiving coil is the same as that of the transmitting coil, which is laid continuously under the road surface, and the receiving coil is installed under the chassis of the electric vehicle; The transmitter compensation circuit includes a resonant capacitor C 1-i With the transmitting coil L 1-i The receiving end compensation circuit includes a resonant capacitor C2 connected in series with the receiving coil L2 to form a series resonance. If the resonant operating frequency of the energy transfer circuit is ω0, then the formula (1) is satisfied: Where, L 1-i is the self-inductance of the i-th transmitting coil, C 1-i is the series compensation capacitor of the i-th transmitting coil, L2 is the self-inductance of the receiving coil, and C2 is the series compensation capacitor of the receiving coil; The inverter power supply is a voltage-type full-bridge inverter power supply, comprising four SiC-MOSFET switching tubes and four uncontrolled diodes, wherein the SiC-MOSFET switching tubes and the uncontrolled diodes are connected in reverse parallel; The rectifier circuit is a single-phase bridge uncontrolled rectifier circuit, including four uncontrollable diodes and a voltage-stabilizing capacitor; It is characterized in that The method comprises the following steps: (1) Control the operating frequency of the inverter power supply to perform frequency scanning between 0 and ω0, and the sampling module collects the output voltage of the inverter power supply in real time and output current (2) Phase comparator real-time comparison and When the phase difference between the two is 0, the working frequency ω is collected at this time. k , setting the electrical parameters of the transmitting coil and the receiving coil to be the same, then: Where L2 is the self-inductance of the receiving coil, L is the simplified self-inductance of the transmitting and receiving coils, and C 1-i is the series compensation capacitor of the i-th transmitting coil, C2 is the capacitance of the receiving compensation circuit, and C is the compensation capacitance of the simplified transmitting and receiving coils; (3) Measure the relationship between the coupling coefficient k and the relative position of the transmitting coil and the receiving coil through simulation or experiment, that is, k(x); (4) Calculate the coupling coefficient k between the transmitting coil and the receiving coil at this time c : Where R L is the load equivalent resistance, R2 is the parasitic resistance of the receiving coil; (5) k c The position of the receiving coil can be obtained in real time by substituting it into the k(x) curve. When the receiving coil is located above the transmitting coil, the inverter power supply output frequency is controlled to ω0, and the receiving end is powered in real time in the resonant state.

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