CN104810906A - Electric automobile wireless charging system based on intelligent coil arrays - Google Patents

Abstract

The invention provides a wireless charging system for electric vehicles based on a smart coil array. The system is connected to a DC microgrid. The system includes a plurality of smart coil array units laid under the road surface and energy receiving units on the electric vehicle; Multiple transmitting coil units in a smart coil array unit paved under the road are connected to each other in a parallel manner, and at the same time, the transmitting coil unit closest to the energy coil unit is connected to the energy coil unit through electromagnetic coupling; the energy coil unit is connected via DC- The AC power changing unit is connected to the DC microgrid; the energy receiving unit on the electric vehicle includes a receiving coil unit and a load coil unit, and is connected with the transmitting coil unit through electromagnetic coupling for energy reception. The beneficial effect is that the effective range of the wireless charging of the system structure is at the cm-m level, which enables energy transmission to cover the entire road surface, and reduces driving restrictions on automobiles. The cost of the charging system is saved, and the complexity of the system design is reduced at the same time.

Description

Electric vehicle wireless charging system based on smart coil array

technical field

The invention relates to wireless charging technology, in particular to a wireless charging system for electric vehicles based on an intelligent coil array.

Background technique

Electric vehicles are considered to be the most environmentally friendly road transportation at present, but there are two important problems that limit their popularization, one is short mileage, and the other is high initial cost. Due to the slow development of battery technology, it is difficult to bring breakthroughs for the development of electric vehicles from the perspective of improving batteries. To solve the problem of short mileage, the conventional strategy is to set up enough charging stations and increase the charging speed. However, different from this conventional gas station strategy, wireless charging technology can be used to complete the charging process of electric vehicles during driving.

Wireless charging technology is derived from wireless power transmission technology. Using electromagnetic coupling, the power supply equipment transmits electric energy to the electric device, and the device uses the received energy to charge the battery and at the same time for its own operation. Compared with wired charging technology, its energy transmission does not require distribution lines, so it is very suitable for power supply of mobile devices such as electric vehicles. With the promotion of the magnetic resonance coupling principle (MRC), the transmission distance and transmission efficiency of wireless charging technology have been qualitatively improved.

According to the inductively coupled wireless power transfer (ICPT) technology, a track spliced by energized coils is laid under the road surface, and the principle of transmitting electric energy similar to a transformer is used to charge a driving electric vehicle. Since the transmission distance of electromagnetic induction charging technology is very short and the transmission efficiency is very low, the requirements for the driving range of the car are relatively strict; at the same time, this type of system also needs to be equipped with a positioning system, which uses infrared sensors to locate the position of the car to determine the location that needs power supply. Coil (orbit).

Contents of the invention

In view of the deficiencies of the above-mentioned electromagnetic induction wireless charging system for electric vehicles, the present invention proposes a wireless charging system for electric vehicles based on a smart coil array. The first purpose is to improve the coverage of energy transmission and reduce the limitation of the driving range of the vehicle. The second purpose is to: To achieve the natural positioning of electric vehicles, the third purpose is to realize the modularization of the charging system and increase its scalability.

In order to achieve the above purpose, the technical solution adopted by the present invention is to provide a wireless charging system for electric vehicles based on a smart coil array, which is connected to a DC microgrid, wherein: the system includes a plurality of smart coils laid under the road surface Array unit, the energy receiving unit on the electric vehicle; each smart coil array unit laid under the road includes an energy coil unit and multiple transmitting coil units, and multiple transmitting coil units are connected to each other in parallel, while the distance from the energy coil The nearest transmitting coil unit of the unit is connected with the energy coil unit through electromagnetic coupling; the energy coil unit is connected with the DC microgrid via the DC-AC power changing unit; the energy receiving and receiving unit on the electric vehicle includes a receiving coil unit and The load coil unit is connected with the transmitting coil unit through electromagnetic coupling for energy reception.

Beneficial effects of the present invention: the effective range of wireless charging based on ICPT technology is generally mm-cm level, and the energy transmission efficiency is low, while the effective range of wireless charging based on magnetic resonance coupling (MRC) in this system structure is cm-cm The M-level can enable energy transmission to cover the entire road surface, reducing the driving restrictions on the car. The system structure uses the intelligent coil array to naturally locate the electric vehicle for energy supply, without adding positioning systems such as infrared sensors, saving the cost of the charging system, and reducing the complexity of the system design. The reduced-scale experiment shows that the energy transmission efficiency of the charging system of the present invention can reach about twice that of other systems of the same scale. The system structure is a modular wireless charging system for electric vehicles, which can be flexibly expanded according to requirements.

Description of drawings

Fig. 1 is the schematic diagram of the smart coil array topological structure of the present invention;

FIG. 2 is an equivalent circuit diagram of the smart coil array wireless charging system of the present invention.

In the picture:

1. Smart coil array unit 2, energy coil unit 3, transmitting coil unit 4, receiving coil unit 5, load coil unit 6, DC microgrid 7, DC-AC power changing unit 8, n position 9, laid under the road surface m position 10, electric vehicle receiving coil inductance L ₃ 11, n position transmitting coil inductance L _2n 12, m position transmitting coil inductance L _2m 13 smart coil array circuit 14, energy coil circuit 15, n position transmitting Coil unit 16, the transmitting coil unit of m position

Detailed ways

The electric vehicle wireless charging system based on the smart coil array of the present invention is described in conjunction with the accompanying drawings.

The key to the wireless charging system for electric vehicles based on the smart coil array of the present invention is to use magnetic resonance coupling technology to design the wireless charging system; the second key is to use the smart coil array to naturally locate the load, that is, the electric vehicle; Array unitization.

The electric vehicle wireless charging system based on the smart coil array of the present invention is connected to the DC microgrid 6, and the system includes a plurality of smart coil array units 1 laid under the road surface and energy receiving units on the electric vehicle; Each intelligent coil array unit 1 laid under the road surface includes an energy coil unit 2 and a plurality of transmitting coil units 3, and the plurality of transmitting coil units 3 are connected to each other in a parallel manner, and the transmitting coil unit 3 closest to the energy coil unit 2 is It is connected with the energy coil unit 2 through electromagnetic coupling; the energy coil unit 2 is connected with the DC microgrid 6 via the DC-AC power changing unit 7; the energy receiving unit on the electric vehicle includes a receiving coil unit 4 and a load The coil unit 5 is connected with the transmitting coil unit 3 through electromagnetic coupling for energy reception.

The plurality of transmitting coil units 3 are connected in a topological manner in parallel to ensure the natural positioning of the smart coil array unit 1 laid under the road to the electric vehicle.

The DC power of the DC microgrid 6 is converted into AC power by the DC-AC power conversion unit 7, and transmitted to the energy coil unit 2, the frequency of the AC power obtained by the power coil unit 2 and the power coil unit 2, the transmitter The coil unit 3, the receiving coil unit 4, and the load coil unit 5 have the same natural frequency, ensuring that the system realizes the wireless connection of the electric vehicle through the magnetic resonance coupling connection of the energy coil unit 2, the transmitting coil unit 2, the receiving coil unit 4, and the load coil unit 5. Charge.

As shown in Figure 1, it is a schematic diagram of the topological structure of the smart coil array of the present invention. The electric vehicle wireless charging system of the present invention includes a plurality of smart coil array units 1 laid under the road surface, and each smart coil array unit laid under the road surface 1 is composed of an energy coil unit 2 and a plurality of transmitting coil units 3, and a DC microgrid 6 is connected to the energy coil unit 2 via a DC-AC power changing unit 7. The receiving coil unit 4 and the load coil unit 5 shown in the figure are the energy receiving and receiving units on the electric vehicle.

The wireless charging system for electric vehicles based on the smart coil array of the present invention uses magnetic resonance coupling technology to realize wireless charging for electric vehicles, and the natural frequency f of the energy coil unit 2, the transmitting coil unit 3, the receiving coil unit 5 and the load coil unit 6 _{is f0} all the same. Its charging process: the DC microgrid 6 transmits the DC power to the DC-AC power conversion unit 7, and the DC-AC power conversion unit 7 converts the DC power into AC power to drive the energy coil unit 2, ensuring that the frequency of the AC power supply is equal to the natural frequency f ₀ , according to the principle of magnetic resonance coupling, the energy is transferred to the load coil unit 5 through the transmitting coil unit 3 and the receiving coil unit 4, so as to realize the power supply to the electric vehicle.

The main structure of the electric vehicle wireless charging system based on the smart coil array of the present invention is the smart coil array unit 1 laid under the road surface, which is composed of a plurality of transmitting coil units 3 connected in parallel. This coil topology can realize the natural charging of the electric vehicle. position. According to the equivalent circuit of the smart coil array wireless charging system of the present invention shown in Figure 2, the process of realizing natural positioning is described:

As shown in Figure 2, when the electric vehicle is located at n position 8, there is a mutual inductance M _2n,3 between the inductance L ₃ 10 of the receiving coil of the electric vehicle and the inductance L _2n 11 of the transmitting coil at position n, so in the smart coil array circuit 13, n The equivalent inductance of the transmitting coil unit 15 at the position is L _2n -M _2n,3 . Compared with other parallel transmitting coil units, its inductance is smaller. According to Kirchhoff's law and Ohm's law, it can be known that at this time the The current flowing through the transmitting coil unit is larger than that of other parallel transmitting coil units. The energy transmitted from the energy coil circuit 14 to the intelligent multi-coil array circuit 13 is mainly gathered at the n position 8, and is utilized by the transmitting coil unit 15 at the n position. Magnetic resonance coupling principle for wireless charging of electric vehicles.

Similarly, as shown in Figure 2, when the electric vehicle travels to position m, there is a mutual inductance between the inductance L ₃ 10 of the receiving coil of the electric vehicle and the inductance L _2m 12 of the transmitting coil at position m, so the equivalent inductance of the transmitting coil unit 16 at position m Smaller, the current flowing through it is relatively large, the energy transmitted from the energy coil circuit 14 to the smart coil array circuit 13 is mainly concentrated at the m position 9, and the transmitting coil unit 16 at the m position uses the principle of magnetic resonance coupling to wirelessly charge the electric vehicle .

The wireless charging system for electric vehicles based on the smart coil array of the present invention includes a plurality of smart coil array units 1 laid under the road surface. Cooperating with grid power supply, each smart coil array unit 1 laid under the road surface can realize natural positioning and wireless charging of electric vehicles. Such array units can be expanded and reduced according to demand; enough array units are reserved, and when a certain array unit fails, it can be replaced in time, saving cost and time.

Claims (3)

1. A wireless charging system for electric vehicles based on a smart coil array, the system is connected with a DC microgrid (6), and it is characterized in that: the system includes a plurality of smart coil array units (1) laid under the road surface, The energy receiving and receiving unit on the electric vehicle; each intelligent coil array unit (1) laid under the road surface includes an energy coil unit (2) and a plurality of transmitting coil units (3), and the multiple transmitting coil units (3) are connected in parallel connected to each other in a manner, while the transmitting coil unit (3) closest to the energy coil unit (2) is connected to the energy coil unit (2) through electromagnetic coupling; the energy coil unit (2) is connected via a DC-AC power change unit ( 7) Connected to the DC microgrid (6); the energy receiving unit on the electric vehicle includes a receiving coil unit (4) and a load coil unit (5), and is connected to the transmitting coil unit (3) through electromagnetic coupling Receive energy. 2. The electric vehicle wireless charging system based on smart coil array according to claim 1, characterized in that: the plurality of transmitting coil units (3) are connected in parallel in a topological manner to ensure that the electric vehicles laid under the road surface The natural positioning of smart coil array units (1) for electric vehicles. 3. The electric vehicle wireless charging system based on smart coil array according to claim 1, characterized in that: the DC power of the DC microgrid (6) is converted into AC power by a DC-AC power conversion unit (7), And transmitted to the energy coil unit (2), the frequency of the AC power obtained by the energy coil unit (2) and the energy coil unit (2), the transmitting coil unit (3), the receiving coil unit (4), the load coil unit (5) The natural frequencies are all the same, ensuring that the system realizes wireless charging of the electric vehicle through the magnetic resonance coupling connection of the energy coil unit (2), the transmitting coil unit (3), the receiving coil unit (4) and the load coil unit (5).