An Optimization Method for the Electromagnetic Field Energy Transfer Efficiency of Wireless Charging for Electric Vehicles

Abstract

The present invention discloses a method for optimizing the electromagnetic field energy transfer efficiency of wireless charging for electric vehicles, comprising the following steps: A. Set a plurality of identification parts at the bottom of the electric vehicle; install a hydraulic lifting platform underground in the parking space, lay a transmitting coil on the hydraulic lifting platform, connect an adjustable capacitor in series on the transmitting coil, and install a distance sensor outside the area where the hydraulic lifting platform is laid; B. Pre-calculate the optimal energy transfer efficiency corresponding to the total mutual inductance value of the coil and the system resonance frequency; C. After the vehicle to be charged drives into the parking space, query the system resonance frequency corresponding to it in the state of the optimal energy transfer efficiency according to the theoretical value of the total mutual inductance of the coil; D. Energize the transmitting coil and calculate the actual energy transfer efficiency of the charging; E. If the actual energy transfer efficiency is less than 80% of the optimal energy transfer efficiency described in step C, adjust the total mutual inductance value of the coil and the system resonance frequency; otherwise, start formal charging. The present invention can achieve rapid optimization of the energy transfer efficiency of wireless charging for each electric vehicle.

Description

Technical Field

[0001] The present invention relates to the technical field of wireless charging for electric vehicles, and in particular to a method for optimizing the electromagnetic field energy transfer efficiency of wireless charging for electric vehicles. Background Art

[0002] With the rapid development of battery and electronic control technologies, the number of electric vehicles has shown explosive growth. Most of the existing charging methods for electric vehicles use wired cables for charging, which has poor flexibility and inconvenience in use. Wireless charging is a charging method that uses mutual inductance coupling between coils for energy transfer, eliminating the need to plug and unplug charging cables, enabling electric vehicles to be charged immediately upon arrival and leave immediately after charging. However, since the charging efficiency of wireless charging is directly related to the coupling parameters between coils, although parameter optimization calculations are performed during design and installation, the actual charging efficiency will decrease due to differences in vehicle parking positions and vehicle chassis heights during actual use. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a method for optimizing the electromagnetic field energy transfer efficiency of wireless charging for electric vehicles, which can solve the deficiencies of the prior art and achieve rapid optimization of the wireless charging energy transfer efficiency for each electric vehicle.

[0004] To solve the above technical problems, the technical solutions adopted by the present invention are as follows.

[0005] A method for optimizing the electromagnetic field energy transfer efficiency of wireless charging for electric vehicles, comprising the following steps:

[0006] A. A plurality of identification parts are arranged outside the receiving coil at the bottom of the electric vehicle; a hydraulic lifting platform is installed underground in the parking space, and a plurality of transmitting coils arranged in a matrix form are laid on the hydraulic lifting platform. Each transmitting coil is connected in series with an adjustable capacitor. A plurality of distance sensors are installed outside the area where the hydraulic lifting platform is laid. The distance sensors determine the relative positions of the receiving coil and the transmitting coil matrix by sensing the identification parts;

[0007] B. The optimal energy transfer efficiency corresponding to the total mutual inductance value of the coils and the system resonance frequency is calculated in advance and the data is stored in a database;

[0008] C. When the vehicle to be charged drives into the parking space, the distance sensors detect the relative positions of the receiving coil and the transmitting coil matrix and calculate the theoretical value of the total mutual inductance of the coils; the system resonance frequency corresponding to the optimal energy transfer efficiency state is queried according to the theoretical value of the total mutual inductance of the coils, and the adjustable capacitor is adjusted according to the queried system resonance frequency;

[0009] D. The transmitting coil is powered on for pre-charging, and the actual energy transfer efficiency of the charging is calculated;

[0010] E. If the actual energy transfer efficiency is less than 80% of the optimal energy transfer efficiency described in step C, stop the pre-charging, adjust the total mutual inductance value of the coils and the system resonance frequency, and then return to step D; when the actual energy transfer efficiency is greater than or equal to 80% of the optimal energy transfer efficiency described in step C, start the formal charging.

[0011] Preferably, the ratio of the diameter of the transmitting coil to the diameter of the receiving coil is 1:10 to 1:7, and the ratio of the area of the matrix region composed of all the transmitting coils to the area of the receiving coil is 3:2 to 2:1.

[0012] Preferably, the distance between the identification part and the edge of the transmitting coil is greater than 20 cm.

[0013] Preferably, in step E, first adjust the total mutual inductance value of the coils by changing the height of the hydraulic lifting platform. After determining the optimal height of the hydraulic lifting platform, further adjust the total mutual inductance value of the coils and the system resonance frequency by adjusting the on / off state of different transmitting coils in the transmitting coil matrix and the capacitance value of the adjustable capacitor connected in series with the energized transmitting coils.

[0014] Preferably, in step E, determine the adjustable range of the total mutual inductance value of the coils by adjusting the height of the hydraulic lifting platform, and select the height of the hydraulic lifting platform corresponding to the adjustable range of the total mutual inductance value with the largest average value of the highest energy transfer efficiency as the adjustment target height.

[0015] Preferably, in step E, determine the transmitting coils directly above and below the receiving coil according to the relative positions of the receiving coil and the transmitting coil matrix, define the above-mentioned transmitting coils as the first transmitting coil group, and position the remaining transmitting coils as the second transmitting coil group; first cut off the power supply of the first transmitting coil group, conduct power-on tests on each of the second transmitting coils in the second transmitting coil group, select the power-on combination mode of the second transmitting coils with the highest energy transfer efficiency, and then conduct power-on tests on each of the first transmitting coils in the first transmitting coil group, select the power-on combination mode of the first transmitting coils with the highest energy transfer efficiency; after determining the power-on state of the transmitting coils, adjust the adjustable capacitors connected in series with the energized transmitting coils.

[0016] The beneficial effects brought by adopting the above technical solutions are as follows: The present invention designs a hydraulic lifting platform that can flexibly adjust the height up and down and a transmitting coil matrix that can flexibly combine on / off states, realizing effective adjustment of the energy transfer efficiency. The adjustment process is divided into two steps. First, optimize the best adjustment range of the energy transfer efficiency by adjusting the height, and then finely adjust the energy transfer efficiency by the on / off state of the transmitting coil matrix to realize the optimal setting of the mutual inductance value and the resonance frequency. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The flowchart of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0018] Referring to Figure 1 , a specific embodiment of the present invention includes the following steps:

[0019] A. A plurality of identification parts are arranged outside the receiving coil at the bottom of the electric vehicle; a hydraulic lifting platform is installed underground in the parking space, and a plurality of transmitting coils arranged in a matrix form are laid on the hydraulic lifting platform. An adjustable capacitor is connected in series with each transmitting coil. A plurality of distance sensors are installed outside the area where the hydraulic lifting platform is laid. The distance sensors determine the relative positions of the receiving coil and the transmitting coil matrix by sensing the identification parts;

[0020] B. The total mutual inductance value of the coils and the optimal energy transfer efficiency corresponding to the system resonance frequency are calculated in advance, and the data is stored in the database;

[0021] C. When the vehicle to be charged drives into the parking space, the distance sensors detect the relative positions of the receiving coil and the transmitting coil matrix and calculate the theoretical value of the total mutual inductance of the coils; the system resonance frequency corresponding to the optimal energy transfer efficiency state is queried according to the theoretical value of the total mutual inductance of the coils, and the adjustable capacitor is adjusted according to the queried system resonance frequency;

[0022] D. The transmitting coils are powered on for pre-charging, and the actual energy transfer efficiency of the charging is calculated;

[0023] E. If the actual energy transfer efficiency is less than 80% of the optimal energy transfer efficiency described in step C, the pre-charging is stopped, the total mutual inductance value of the coils and the system resonance frequency are adjusted, and then the process returns to step D; when the actual energy transfer efficiency is greater than or equal to 80% of the optimal energy transfer efficiency described in step C, the formal charging starts.

[0024] The ratio of the diameter of the transmitting coil to the diameter of the receiving coil is 1:10 to 1:7, and the ratio of the area of the matrix region composed of all the transmitting coils to the area of the receiving coil is 3:2 to 2:1.

[0025] The distance between the identification part and the edge of the transmitting coil is greater than 20 cm.

[0026] In step E, first, the total mutual inductance value of the coils is adjusted by changing the height of the hydraulic lifting platform. After determining the optimal height of the hydraulic lifting platform, the total mutual inductance value of the coils and the system resonance frequency are further adjusted by adjusting the on / off states of different transmitting coils in the transmitting coil matrix and the capacitance value of the adjustable capacitor connected in series with the energized transmitting coils.

[0027] In step E, the adjustable range of the total mutual inductance value of the coils is determined by adjusting the height of the hydraulic lifting platform, and the height of the hydraulic lifting platform corresponding to the adjustable range of the total mutual inductance value with the largest average value of the highest energy transfer efficiency is selected as the target height for adjustment.

[0028] In step E, the adjustable range of the total mutual inductance value of the coil is determined by adjusting the height of the hydraulic lifting platform, and the height of the hydraulic lifting platform corresponding to the adjustable range of the total mutual inductance value of the coil with the maximum average value of the highest energy transfer efficiency is selected as the adjusted target height.

[0029] In step E, the transmitting coil directly corresponding to the receiving coil up and down is determined according to the relative positions of the receiving coil and the transmitting coil matrix, and the above transmitting coil is defined as the first transmitting coil group, and the remaining transmitting coils are positioned as the second transmitting coil group; first, the first transmitting coil group is powered off, and each second transmitting coil in the second transmitting coil group is powered on for testing, and the power-on combination mode of the second transmitting coil with the maximum energy transfer efficiency is selected, and then each first transmitting coil in the first transmitting coil group is powered on for testing, and the power-on combination mode of the first transmitting coil with the maximum energy transfer efficiency is selected; after the power-on state of the transmitting coil is determined, the adjustable capacitor connected in series on the powered-on transmitting coil is adjusted.

[0030] The present invention can quickly optimize parameter configuration for the actual parking positions of different vehicles, without excessive requirements for vehicle size and parking position, and without installing complex vehicle positioning and attitude adjustment devices, enabling ordinary drivers to conveniently drive into the parking space and directly perform efficient wireless charging.

[0031] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments, and what is described in the above embodiments and the specification only illustrates the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. An optimization method for the electromagnetic field energy transfer efficiency of wireless charging of electric vehicles, characterized in that it includes the following steps: A. Set several identification parts outside the receiving coil at the bottom of the electric vehicle; install a hydraulic lifting platform underground in the parking space, lay several transmitting coils arranged in a matrix form on the hydraulic lifting platform, connect an adjustable capacitor in series with each transmitting coil, and install several distance sensors outside the area where the hydraulic lifting platform is laid. The distance sensors determine the relative positions of the receiving coil and the transmitting coil matrix by sensing the identification parts; B. Pre-calculate the optimal energy transfer efficiency corresponding to the total mutual inductance value of the coils and the system resonance frequency, and store the data in the database; C. After the vehicle to be charged drives into the parking space, detect the relative position between the receiving coil and the transmitting coil matrix through the distance sensor and calculate the theoretical value of the total mutual inductance of the coils; Query the system resonance frequency corresponding to it in the state of the optimal energy transfer efficiency according to the theoretical value of the total mutual inductance of the coils, and adjust the adjustable capacitor according to the queried system resonance frequency; D. Energize the transmitting coil for pre-charging and calculate the actual energy transfer efficiency of the charging; E. If the actual energy transfer efficiency is less than 80% of the optimal energy transfer efficiency described in step C, stop the pre-charging. First, adjust the total mutual inductance value of the coils by changing the height of the hydraulic lifting platform. After determining the optimal height of the hydraulic lifting platform, further adjust the total mutual inductance value of the coils and the system resonance frequency by adjusting the on-off of different transmitting coils in the transmitting coil matrix and the capacitance value of the adjustable capacitor connected in series with the energized transmitting coil, and then return to step D; when the actual energy transfer efficiency is greater than or equal to 80% of the optimal energy transfer efficiency described in step C, start formal charging.

2. The optimization method for the electromagnetic field energy transfer efficiency of wireless charging of electric vehicles according to claim 1, characterized in that: The ratio of the diameter of the transmitting coil to the diameter of the receiving coil is 1:10 to 1:7, and the ratio of the area of the matrix area composed of all the transmitting coils to the area of the receiving coil is 3:2 to 2:

1.

3. The optimization method for the electromagnetic field energy transfer efficiency of wireless charging of electric vehicles according to claim 1, characterized in that: The distance between the identification part and the edge of the transmitting coil is greater than 20 cm.

4. The optimization method for the electromagnetic field energy transfer efficiency of wireless charging of electric vehicles according to claim 1, characterized in that: In step E, determine the adjustable range of the total mutual inductance value of the coils by adjusting the height of the hydraulic lifting platform, and select the height of the hydraulic lifting platform corresponding to the adjustable range of the total mutual inductance value with the largest average value of the highest energy transfer efficiency as the adjustment target height.

5. The optimization method for the electromagnetic field energy transfer efficiency of wireless charging of electric vehicles according to claim 1, characterized in that: In step E, determine the transmitting coil directly above or below the receiving coil according to the relative positions of the receiving coil and the transmitting coil matrix, define the above transmitting coil as the first transmitting coil group, and position the remaining transmitting coils as the second transmitting coil group; first, cut off the power supply of the first transmitting coil group, conduct power-on tests on each second transmitting coil in the second transmitting coil group, select the power-on combination mode of the second transmitting coils with the highest energy transfer efficiency, then conduct power-on tests on each first transmitting coil in the first transmitting coil group, and select the power-on combination mode of the first transmitting coils with the highest energy transfer efficiency; after the power-on states of the transmitting coils are determined, adjust the adjustable capacitors connected in series on the powered transmitting coils.

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