KR20200073464A - Power transfer direction control device and wireless charging system including the same - Google Patents

Abstract

Disclosed are a power transmission direction control device and a wireless charging system including the same. According to an aspect of the present embodiment, the wireless charging system capable of controlling a power transmission direction includes: a transmitting device including a transmitting coil; a receiving device including a receiving coil; and a plurality of coupling units positioned between the transmitting device and the receiving device and comprising a coupling coil and a first capacitor connected in parallel with the coupling coil. The power transmission direction is controlled according to whether a resonance frequency formed by the transmitting device and the receiving device is changed by each of the plurality of coupling units.

Description

Power transmission direction control device and wireless charging system including the same{POWER TRANSFER DIRECTION CONTROL DEVICE AND WIRELESS CHARGING SYSTEM INCLUDING THE SAME}

The present invention relates to a power transmission direction control device and a wireless charging system including the same.

The content described in this section merely provides background information for the present invention and does not constitute a prior art.

Exhaust gas emitted by automobiles using conventional fossil fuels as an energy source is not only a source of pollution, but also a major cause of global warming. As a result, countries around the world are planning to implement or enforce the prohibition of sales of internal combustion locomotives, restrictions on the operation of diesel cars, and mandatory sales policies for eco-friendly vehicles.

In Korea, among other things, it supports the supply of electric vehicles. For example, if the driver purchases an electric vehicle, the subsidies are provided, and the charging infrastructure is built in the country so that there is no inconvenience in using the electric vehicle. The wireless charging method of an electric vehicle that can be built as a charging infrastructure can be roughly divided into two types.

The first is a magnetic induction method, which transmits electric power similar to using a magnetic induction phenomenon between a primary coil and a secondary coil of a transformer, and is a method in which a transmitting coil and a receiving coil are located at close range. That is, the magnetic induction method is sensitive to the distance between the transmitting coil and the receiving coil because the magnetic field must be able to jointly affect the coil at a close distance. In addition, the magnetic induction method is very sensitive to the position matching of the receiving coil. When applying the self-induction method to the charging of an electric vehicle, a method of mechanically moving one of the coils is adopted to narrow the gap between the transmitting coil and the receiving coil, but the size and shape of each vehicle are different and the gap is narrowed. It is difficult to accurately align the position of. Further, even in this case, since the electric vehicle can pass over the transmission coil usually buried underground, the coil may be damaged or the mechanical shape may be damaged by the weight of the vehicle.

The second method is a magnetic resonance method, in which a power is transmitted by forming a magnetic resonance using a frequency in a range of several MHz to several tens of MHz. The magnetic resonance method is more efficient because it can transmit energy over a long distance than the magnetic induction method. The self-resonance method has been recently used to charge the battery of a mobile phone.

In addition, there is an electromagnetic wave method. The electromagnetic wave method is the same mechanism as the transmission of information using electromagnetic waves, but in order to transmit the required level of power, the output must be increased, and in this case, it is difficult to avoid the problem of the human body caused by electromagnetic waves. However, long-distance transmission is also possible, so research is being conducted in the industry, not for personal use.

The present embodiment has a main object to provide a method and system for controlling a power transmission direction for wireless charging of an electric vehicle.

According to an aspect of the present embodiment, a wireless charging system capable of controlling power transmission direction includes: a transmitting device including a transmitting coil, a receiving device including a receiving coil, and a coupling coil positioned between the transmitting device and the receiving device , And a plurality of coupling parts composed of a first capacitor connected in parallel with the coupling coil, and power depending on whether a resonance frequency formed by the transmitting device and the receiving device is changed by each of the plurality of coupling parts. It is characterized by controlling the direction of transmission.

According to another aspect of this embodiment, an apparatus for controlling a power transmission direction includes two or more coupling parts, and each coupling part comprises a coil and a first capacitor connected in parallel with the coil, and transmits It is characterized in that the power transmission direction is controlled according to whether the resonance frequency formed by the device and the receiving device is changed by the respective coupling units.

As described above, according to the present embodiment, in order to align the transmitting coil and the receiving coil, it is possible to control the transmission power direction by using an electrical switching technique rather than a mechanical method.

According to this embodiment, it is possible to generate a high-efficiency power transmission from the transmitting coil buried underground to the receiving coil located under the vehicle by controlling the coupling coil located in the reverse preventing jaw.

According to this embodiment, power can be transmitted with high efficiency without accurately aligning the transmitting coil and the receiving coil.

In addition, according to the present embodiment, it is difficult to implement while minimizing additional structures by arranging a coupling coil capable of controlling the transmission direction of the transmitting coil and controlling the power transmission direction with an electrical switching technique inside the normally-retracted anti-jaw. It is possible to enable power transmission to the receiving coil.

1 is a view schematically showing a wireless charging system including a power transmission direction control device according to an embodiment of the present disclosure;
FIG. 2A is a view showing an arrangement of coils constituting a wireless charging system according to an embodiment of the present disclosure, as viewed from above;
Figure 2b is a view showing a side view of the arrangement of the coils constituting the wireless charging system according to an embodiment of the present disclosure,
Figure 2c is a view showing the operating principle of the coils constituting the wireless charging system according to an embodiment of the present disclosure,
3A is a diagram illustrating an entire circuit diagram of a wireless charging system according to an embodiment of the present disclosure,
3B is a view showing an equivalent circuit when the resonance frequency of the wireless charging system does not change by the coupling unit according to an embodiment of the present disclosure,
3C is a view showing an equivalent circuit when a resonance frequency of a wireless charging system is changed by a coupling unit according to an embodiment of the present disclosure,
4 is a view showing an example of a circuit for increasing the quality factor of the coupling portion according to the present disclosure.

Hereinafter, some embodiments of the present invention will be described in detail through exemplary drawings. It should be noted that in adding reference numerals to the components of each drawing, the same components have the same reference numerals as possible even though they are displayed on different drawings. In addition, in describing the present invention, when it is determined that detailed descriptions of related well-known structures or functions may obscure the subject matter of the present invention, detailed descriptions thereof will be omitted.

In addition, in describing the components of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are only for distinguishing the component from other components, and the nature, order, or order of the component is not limited by the term. Throughout the specification, when a part is'included' or'equipped' a component, this means that other components may be further included rather than excluded, unless specifically stated otherwise. . In addition,'… Terms such as "unit" and "module" mean a unit that processes at least one function or operation, which may be implemented by hardware or software or a combination of hardware and software.

In the present disclosure, a magnetic resonance method is applied to the charging of an electric vehicle.

Specifically, the magnetic resonance method is a method of transmitting power by forming a magnetic coupling characteristic in space using a higher frequency than the magnetic induction method. The magnetic resonance method can transmit energy to a long distance rather than the magnetic induction method, and forms a space for transmitting power, thereby enabling power transmission even when the positional consistency between the transmitting coil and the receiving coil is low. Since the magnetic resonance method is designed to have a coupling coil having a directionality between the transmitting coil and the receiving coil or to increase the directionality to the transmitting coil and the receiving coil, the coil and mechanism design results are more effective in transmitting power than the existing magnetic induction method. It has a big impact. In an electric vehicle charging system based on a self-resonance method, a separate space for a coupling coil is provided in a vehicle or in the ground or by physically moving the position of the coupling coil to transmit electric power in a desired direction. Since it does not control the generated space, the high output power signal can be leaked to the outside, which poses a problem to the human body and the surrounding environment.

In the present disclosure, a reverse preventing jaw is described as an example of a power transmission direction control device, but it is not necessarily a reverse preventing jaw, and may be another device including a configuration of the reverse preventing jaw of the present disclosure.

1 is a diagram briefly showing a wireless charging system including a power transmission direction control device according to an embodiment of the present disclosure.

1 shows an electric vehicle 110 parked in a parking lot. In general, on the floor of the parking lot, a reverse preventing jaw 120 is installed in addition to the parking line to prevent the vehicle from reversing.

The wireless charging system according to the present disclosure includes a power transmission device including a transmission coil 130 on the floor of a parking lot, and a power transmission direction control consisting of a coupling unit (not shown) including the coupling coil 150 of the reverse preventing jaw 120 It is composed of a device, and a power receiving device including a receiving coil 140 of an electric vehicle, from the transmitting coil 130 on the floor of the parking lot to the receiving coil 140 of the electric vehicle through the coupling coil 150 of the coupling unit. Power is transmitted. In the present disclosure, the direction of power transmission may be controlled using the coupling coil 150 of the coupling unit.

The arrangement and operation principle of the transmitting coil 130, the coupling coil 150, and the receiving coil 140, which are the main components of the wireless charging system, will be described in detail in the following drawings.

Figure 2a is a view showing the arrangement of the coils constituting the wireless charging system according to an embodiment of the present disclosure viewed from the top, Figure 2b is an arrangement of the coils constituting the wireless charging system according to an embodiment of the present disclosure It is a view showing the state viewed from the side.

In Figures 2a and 2b, the transmitting coil 130 may be buried in the basement of the reverse preventing jaw installed in the parking lot. The plurality of coupling coils 151, 152, 153, 154, 155, 156, 157, 158, and 159 may be included inside the reverse preventing jaw, and may be located on the upper portion of the transmitting coil 130. The receiving coil 140 may be installed inside the electric vehicle.

When the electric vehicle is parked in a parking lot equipped with a wireless charging system for charging, the receiving coil 140 may be positioned to overlap with some of the plurality of coupling coils (151, 152, 153, 154, 155, 156). have. The degree of overlap may vary depending on the size, shape, and driver's manipulation of the electric vehicle. At this time, power may be transmitted only through the coupling coil overlapping the receiving coil 140.

As a result, in FIGS. 2A and 2B, three coupling coils 157, 158, and 159 of the plurality of coupling coils do not overlap with the receiving coil 140 in position and do not transmit power, and six coupling coils (151, 152, 153, 154, 155, 156) are overlapped in position with the receiving coil 140 may transmit power.

2C is a view showing the operating principle of the coils constituting the wireless charging system according to an embodiment of the present disclosure.

It is assumed that the resonance frequency of a system composed of a transmitting device and a receiving device is f _on .

Figure 2c shows a cross-section of a wireless charging system, even if the coupling coil (151, 154) (i.e., the coupling portion) is located between the transmitting coil 130 and the receiving coil 140 to transmit power (transmission coil ( 130, if the resonant frequency formed by the receiving coil 140 and the coupling coils 151 and 154 (that is, the coupling unit) is still equal to f _on , the transmitting coil 130 and the coupling coil 151, 154) primary coupling occurs, secondary coupling occurs between the receiving coil 140 and the coupling coils 151 and 154, resulting in power from the transmitting coil 130 to the receiving coil 140 It is transmitted.

However, since the coupling coil 157 existing in the region where the receiving coil 140 is not located is not necessary for power transmission, the resonance frequency formed by the coupling coil 157 and the transmitting coil 130 is f It can be _changed to _off so that coupling does not occur. This will be described in detail with reference to the following drawings.

3A is a diagram illustrating an entire circuit diagram of a wireless charging system according to an embodiment of the present disclosure.

A wireless charging system according to an embodiment of the present disclosure may include a transmitting device, a coupling unit, and a receiving device. In FIG. 3A, the coupling unit is described as one, but the wireless charging system may include a plurality of coupling units. The transmitting device may include a transmitting coil 130, a resistor, and a capacitor. In FIG. 3A, the transmitting coil 130 and the resistor are connected in series, and the capacitor is connected in parallel with the transmitting coil 130 and the resistor, but the detailed configuration thereof may be changed.

The coupling portion may be composed of a coupling coil 150 and a circuit 320 for increasing the quality factor. The circuit 320 for increasing the quality factor will be described in detail with reference to FIG. 4 below.

In addition, the receiving device may include a receiving coil 140, a resistor, a capacitor, a diode, and the like. Similar to the transmitting device, the receiving coil 140 and the resistor are connected in series, and the capacitor is connected in parallel with the receiving coil 140 and the resistor, but likewise, the detailed configuration may be changed.

A mutual inductance K ₁ 310 may occur between the transmitting coil 130 of the transmitting device and the coupling coil 150 of the coupling part, and the coupling coil 150 of the coupling part and the reception of the receiving device A mutual inductance K ₂ 312 may be generated between the coils 140. The resonant frequency of the wireless charging system takes into account not only the inductance of each device's coil itself, but also mutual inductance between coils.

3B is a diagram illustrating an equivalent circuit when the resonance frequency of the wireless charging system does not change by the coupling unit according to an embodiment of the present disclosure.

Specifically, FIG. 3B shows an equivalent circuit when the resonance frequency of the wireless charging system including the coupling unit and the resonance frequency of the wireless charging system not including the coupling unit are the same.

According to this embodiment, the power transmission direction should be controlled by adjusting the resonance frequency of the entire wireless charging system including the coupling coil, and the resonance frequency of the entire system including the coupling coil is determined by using the current flowing in the transmission coil. You can. The higher the efficiency of the power transmitted to the receiving coil, the closer the impedance between the transmitting coil and the receiving coil is to zero, so the current flowing through the transmitting coil becomes the maximum.

3C is a diagram illustrating an equivalent circuit when a resonance frequency of a wireless charging system is changed by a coupling unit according to an embodiment of the present disclosure.

Specifically, FIG. 3C shows an equivalent circuit when the resonance frequency of the wireless charging system including the coupling unit and the resonance frequency of the wireless charging system not including the coupling unit are not the same.

When the resonance frequency of the wireless charging system including the coupling unit is not maintained, coupling does not occur and power is not transmitted to the receiving device.

4 is a view showing an example of a circuit for increasing the quality factor of the coupling portion according to the present disclosure.

First, the coupling part of the power transmission direction control device may include other elements in addition to the coupling coil, and the power transmission direction control device may be composed of a plurality of coupling parts. At this time, to increase the power transmission efficiency of the power transmission direction control device may include a circuit for increasing the quality factor as shown in Figure 4, the circuit for increasing the quality factor is a high-quality fixed capacitor, that is, the first capacitor 420 and It can be configured by connecting a low-quality variable capacitor, that is, the second capacitor 440 in parallel. In Fig. 4, the resistances R _p 410 and R _pv 430 are due to the characteristics of the first and second capacitors.

The resonance frequency and the quality factor (Q) of the power transmission direction control device may be expressed as Equation 1 below.

Here, C _total = C + C _v , R _total = R _p ∥ R _pv .

When the same resonant frequency is implemented using a fixed capacitor, and when implemented using a fixed capacitor and a variable capacitor as shown in FIG. 4, Q can be implemented larger than in the latter case. For example, if C: C _v = 4: 1 and R _p : R _pv = 1: 4, Q is increased by 1.25 times. Therefore, the resonance frequency is determined by C _total , but the value of Q can be largely realized by fixing C _total and varying the ratio of C and Cv.

The above description is merely illustrative of the technical idea of the present embodiment, and those skilled in the art to which this embodiment belongs may be capable of various modifications and variations without departing from the essential characteristics of the present embodiment. Therefore, the present embodiments are not intended to limit the technical spirit of the present embodiment, but to explain, and the scope of the technical spirit of the present embodiment is not limited by these embodiments. The scope of protection of the present embodiment should be interpreted by the claims below, and all technical spirits within the equivalent range should be interpreted as being included in the scope of the present embodiment.

110: electric vehicle 120: reverse chin
130: transmitting coil 140: receiving coil
150: coupling coil

Claims (9)

In the wireless charging system capable of controlling the power transmission direction,
A transmitting device comprising a transmitting coil,
A receiving device comprising a receiving coil, and
It is located between the transmitting device and the receiving device, and includes a plurality of coupling parts comprising a coupling coil and a first capacitor connected in parallel with the coupling coil,
A wireless charging system characterized by controlling the direction of power transmission according to whether the resonant frequency formed by the transmitting device and the receiving device is changed by each of the plurality of coupling parts. According to claim 1,
A wireless charging system characterized by controlling the direction of power transmission in a direction in which the resonance frequency formed by the transmitting device and the receiving device is not changed by each of the plurality of coupling parts. According to claim 1,
A wireless charging system, characterized in that the plurality of coupling parts are installed on the reverse preventing jaw. According to claim 1,
Each of the plurality of coupling parts,
Further comprising a second capacitor having a variable capacitance,
The second capacitor is connected to the first capacitor in parallel to control the quality factor wireless charging system. According to claim 1,
Each of the plurality of coupling parts,
Wireless charging system, characterized in that to control the direction of the power transmission by controlling each of the plurality of coupling units to maximize the current consumption of the transmitting device. In the apparatus for controlling the power transmission direction,
It includes two or more coupling parts,
Each coupling portion is composed of a coil and a first capacitor connected in parallel with the coil,
Power transmission direction control device, characterized in that for controlling the direction of power transmission according to whether the resonant frequency formed by the transmitting device and the receiving device is changed by the respective coupling units. The method of claim 6,
Power transmission direction control device, characterized in that for controlling the direction of the power transmission in a direction that does not change the resonance frequency formed by the transmitting device and the receiving device by each of the coupling unit. The method of claim 6,
The coupling portion,
Further comprising a second capacitor connected in parallel with the first capacitor,
The second capacitor is a power transmission direction control device, characterized in that for adjusting the quality factor of the coupling portion. The method of claim 6,
Power transmission direction control device, characterized in that for controlling the respective coupling units to maximize the current consumption in the transmitting device.

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