Patent Description:
Due to global warming, the use of electric power using batteries as an energy source to replace petroleum energy is increasing for transportation means such as automobiles and railroads. Currently, there has been a limit to the more general distribution of electric vehicles due to the insufficient capacity of the battery, which requires a short driving range and frequent charging, as well as insufficient infrastructure such as charging stations and the time required for charging. However, a power supply system has also been installed to enable wireless charging on the road while driving.

<FIG> is a diagram illustrating a power supply line of a wireless charging system <NUM> while driving of a conventional wireless charging electric vehicle. The power supply line is placed on the left and right with the inverter <NUM> as the center and is composed of a single coil.

From the inverter <NUM>, a sinusoidal current is applied to the power supply line composed of the common line portion <NUM> and the power supply region <NUM>, and the applied current returns to the inverter <NUM>.

In this configuration, it is possible to wirelessly charge electric vehicles and industrial equipment by composing a power supply line without too much trouble in the low frequency range (<NUM>-<NUM>). However, due to the weight and size of the wireless charging pad installed in the vehicle, EMF, and the limitations of wireless charging which is relatively expensive compared to wired charging, the frequency of wireless charging is being changed from <NUM>-<NUM> to <NUM> based on many studies. Although advantages can be secured according to the changed frequency, it has the disadvantage that the problem of withstand voltage for frequency increase always exists.

That is, if the frequency is raised from <NUM>-<NUM> to <NUM> according to the current wireless charging trend for electric vehicles, the withstand voltage between both ends in the same power supply line increases by about <NUM> times, which may cause problems such as discharge and leakage current, etc. In order to suppress this, a method of shortening the length of the power supply line or reducing the current used may be proposed. However, if the length is shortened, the charging time of the electric vehicle while driving is shortened, resulting in a problem that the charging amount is significantly reduced. Reducing the current may also be a solution, but when the current is reduced, a voltage lower than the battery voltage is formed as an excitation electromotive force, which may cause a problem in that charging the battery is not easy. In addition to the frequency problem, in the case of the existing wireless charging power supply system <NUM> while driving an electric vehicle, a single coil is wound in one turn in the vehicle travel direction, so compatibility with wireless charging pads attached to other vehicles may be lacking.

The present invention was devised to solve such problems and the object of the present invention is to provide a wireless charging power supply and pick-up system that more effectively reduces the withstand pressure of the power supply line, improves the compatibility with various wireless charging pick-up pads installed in the vehicle in a way that further reduces the cost, and also reduces EMI (ElectroMagnetic Interference) of the power supply line.

Another object of the present invention is to provide a new method for improving the limitation of the power supply line section length and the problem of dead zones during wireless charging while driving.

Systems, methods, and apparatus are disclosed in <CIT> for wirelessly charging an electric vehicle. In one aspect, a method of wirelessly charging an electric vehicle is provided. The method includes, obtaining a request from the electric vehicle for a level of charging power to be delivered from a power transmitter to the electric vehicle via a charging field. The method further includes controlling a current or voltage of the power transmitter based on a power efficiency factor and the requested level of charging power.

In <CIT> on the ground, a plurality of primary power supply transformers are separately installed with a longitudinal direction of magnetic poles matching a vehicle traveling direction. The primary power supply transformers each include a double-sided coil with an H-shaped core around which a wire is wound. On a vehicle, a secondary power supply transformer including an H-shaped core is mounted with a longitudinal direction of magnetic poles matching a vehicle front-back direction.

In <CIT> a contactless power transmission system is provided for supplying power contactlessly from a power transmission apparatus to a power reception apparatus.

The method of <CIT> involves activating only stationary primary coils, which are magnetically coupled with a secondary coil of moving objects due to an instantaneous position of the objects, where the activation follows a movement of the moving objects.

To achieve the above-mentioned objects, in accordance with one aspect of the present invention, there is provided a system for controlling the wireless charging power of electric in motion, comprising: a power supply cable for generating power for wireless charging by flowing an AC current; an inverter for controlling the supply of the AC current flowing through the power supply cable and including a relay unit for adjusting the phase of the AC current to <NUM> degrees or <NUM> degrees; and, a capacitor unit including a relay for adjusting the phase of the AC current to <NUM> degrees or <NUM> degrees under the control of the inverter, and one or more capacitor for offsetting the inductance of the power supply cable, wherein a first part of the power supply cable is connected between the inverter and the capacitor unit without returning to the inverter, when two or more capacitor units are provided, another part of the power supply cable is connected between the nth capacitor unit and the (n+<NUM>)th capacitor unit without returning to the nth capacitor unit, wherein a final part of the power supply cable is connected between the last capacitor unit and the inverter, wherein a power supply region is made between the inverter and the capacitor unit via the first part of the power supply cable and the final part of the power supply cable, when two or more capacitor units are provided, an additional power supply region is made between each capacitor units via the corresponding another part of the power supply cable and the final part of the power supply cable, wherein a final power supply region is made after the last capacitor unit via the final part of the power supply cable only, wherein each power supply region acts like a coil for generating power for wireless charging.

The coil constituting the power supply cable may be composed of one pair or two or more pairs.

The system may further comprise a ferromagnetic power supply core under the power supply cable.

Preferably, when the power supply cable consists of n (n≥<NUM>) pairs of coils, each coil can independently adjust the current phase by means of the relay, so any combination of <NUM> degree or <NUM> degree phase is possible for the n pairs of coils, and wherein the wireless power supplied through the power supply cable is controlled by the control of the current phase combination.

Preferably, when the power supply cable consists of n (n≥<NUM>) pairs of coils, each coil is arranged to be in contact without a separation distance, or arranged to be spaced apart from each other by a certain distance. The coil and the power supply core constituting the power supply cable may be arranged to be in contact without a separation distance, or arranged to be spaced apart from each other by a certain distance.

Preferably, each coil in a section in which each coil constituting the power supply cable is collected is set in a direction of current so that the magnetic field is offset by more than a preset standard.

The system, in a section where each coil constituting the power supply cable is collected, may further comprise a shielding tube surrounding the entire coil to shield the magnetic field.

Preferably, when the electric vehicle enters a power supply section, the inverter detects a location of the electric vehicle and information on a pick-up mounted on the electric vehicle, and controls the electric power at a point where the electric vehicle is located according to the detected pick-up information; and wherein, when the electric vehicle leaves the location, the inverter controls to cut off the electric power at the location. The location of the electric vehicle may be a power supply segment in which the electric vehicle is located. The information on the pick-up may be a type of the pick-up or a height of the pick-up from the ground.

In accordance with another aspect not according to the invention, present for illustration purposes only, there is provided a method of controlling power supply of the wireless charging power supply system of the present invention, comprising the steps of: (a) detecting, by the inverter, a position of the electric vehicle equipped with a pick-up when the electric vehicle enters a power supply section controlled by the inverter; (b) determining, by the inverter, information on the pick-up mounted on the electric vehicle; (c) switching, by the inverter, the position where the electric vehicle is located to a charging mode according to the determined pick-up information, and controlling the power to be supplied to the position; and, (d) switching, by the inverter, when the electric vehicle leaves the position, the position to off mode to cut off the power. Preferably, the position of the electric vehicle is a power supply segment in which the electric vehicle is located.

The information on the pick-up may be a type of the pick-up or a height of the pick-up from the ground.

According to the present invention, it is possible to expand the wireless power supply line while driving by solving the conventional withstand voltage problem on the power supply line with a capacitor provided in a 'box' or an 'inverter' located outside the road, a power supply line design, and a common line arrangement design. According to this scalability, there is an effect of greatly improving the economic problem of the wireless charging system.

At the same time, in contrast to the conventional method of maintaining compatibility with various wireless charging and pick-up pads installed in the vehicle by using multiple inverters, a wireless charging and pick-up system that satisfies such compatibility at a lower cost is provided by utilizing the relays present in the 'box' and 'inverter'. Furthermore, there is an effect of reducing EMI (ElectroMagnetic Interference) of the power supply line by maximizing the magnetic field cancellation effect by the design of the common line and the shielding tube.

In addition, the present invention has an effect of providing a new method for improving the limitation of the length of the power supply line section and the problem of dead zones during wireless charging while driving.

The terms or words used in the present specification and claims should not be construed as being limited to conventional or dictionary meanings and, based on the principle that the inventor can appropriately define the concept of a term in order to explain his invention in the best way, it should be interpreted as a meaning and concept consistent with the technical idea of the present invention. The embodiments described in the present specification and the configurations shown in the drawings are only the most preferred embodiment of the present invention and do not represent all the technical spirit of the present invention. So at the time of the present application, it should be understood that various equivalents and modifications may be substituted for them at the time of filing the present application.

<FIG> is a schematic diagram illustrating a wireless charging power supply system according to the present invention when an electric vehicle on a road.

Hereinafter, 'power supply cable' or 'power supply coil' will be used interchangeably with the same meaning.

The wireless charging power supply system <NUM> according to the present invention performs wireless power transfer of an electric vehicle <NUM> (bus, tram, train, passenger car, etc.). The power supply line includes a power supply unit composed of a plurality of power supply pads, an inverter <NUM> supplying AC power to the power supply unit, and a common line <NUM> connecting the inverter <NUM> and the power supply unit. The power supply unit includes a power supply core made of a ferromagnetic material and a power supply cable <NUM>.

The configuration of the inverter <NUM> or the box <NUM> of the wireless charging power supply system <NUM> of the present invention is not limited to the inverter or box, and may include a switch or other power device. Since these devices also implement the same functions as those implemented through an inverter or a box, they will be collectively referred to as the inverter <NUM> and box <NUM> in the following description. The term 'box' means a box comprising a circuit unit that includes a capacitor and a relay. Hereinafter, it will be referred to as a 'capacitor unit <NUM>' to distinguish it from the inverter <NUM>. Such a relay is also provided in the inverter <NUM>.

In the present invention, as shown in <FIG>, the common line connecting the power supply unit and the inverter does not return but are extended and connected to the next inverter or capacitor unit <NUM>. Similarly, even when two or more capacitor units <NUM> are provided (<NUM>, <NUM>. ), as shown in <FIG>, the other end of the power supply cable having one end connected to the nth capacitor unit is connected to the (n+<NUM>)th capacitor unit without returning to the nth capacitor unit.

The wireless charging power supply system <NUM> of the present invention of <FIG> includes a power supply line having compatibility so that charging is possible even when various types of wireless charging pads are attached to various types of vehicles. When the power supply line is configured as shown in <FIG>, the withstand voltage of the power supply line can be more effectively reduced through the capacitor provided in the inverter <NUM> or in the capacitor unit <NUM>. The reason that the withstand voltage of the power supply line can be reduced is because the capacitor cancels the inductance generated in the power supply line.

Furthermore, an advantage of the present invention is that a plurality of inverters are not used to implement the above-described compatibility. When a plurality of inverters are used, a large amount of installation cost is incurred, thereby lowering the economic feasibility. In the present invention, such compatibility is sufficiently secured through one inverter <NUM> and one or more capacitor units <NUM> connected to the inverter <NUM> as shown in <FIG>. That is, compatibility can be secured by changing the current phase through the relay disposed on the inverter <NUM> or the capacitor unit <NUM>. A method of implementing such compatibility will be described later in detail with reference to <FIG>.

In addition, the shape of the power supply line of the wireless charging power supply system <NUM> may have various shapes, including an oval or circular structure. As the power supply core, a ferromagnetic material such as a ferrite core may or may not be accompanied. When a ferromagnetic material is provided as a power supply core, an embodiment of the shape of such a ferromagnetic material will be described later with reference to <FIG>.

In the coil structure of the power supply line, one coil may be configured as a pair or may be configured as two or more pairs, an example of which is shown in <FIG>.

In the case of a power supply line composed of two or more pairs of coils, the current direction of each coil of the power supply line may be made in all possible combinations. An interval of a pair of coils or two or more pairs of coils may include various intervals including equal intervals, which will be described later with reference to <FIG> and <FIG>.

<FIG> is a view showing the coil structure of the power supply line of the wireless charging power supply system <NUM> according to the present invention and <FIG> is a diagram showing the shape and structure of a ferromagnetic material forming a power supply core of a wireless charging power supply system <NUM> according to the present invention. The shape and structure of the ferromagnetic material may include bar-type, L-type, W-type, and all deformed shapes thereof.

In <FIG>, a cross-section embodiment <NUM> of the power supply cable <NUM> constituting the power supply line, that is, a cross-section indicating the direction of current flowing in the power supply cable <NUM> is shown.

As in the cross-section embodiment <NUM>, the power supply line may be composed of a single coil <NUM> or a plurality of coils <NUM>, <NUM>, <NUM>. In the drawing, the direction in which the current flows out is indicated by '·' and the direction in which the current flows in is indicated by 'X'. In this drawing, only three examples of <NUM>, <NUM>, and <NUM> are illustrated in the case of using two coils, but any combination of two '·' and two 'X' is of course possible.

According to the control of the relay of the inverter <NUM> and the relay of the capacitor unit <NUM>, the direction of the current in each coil can be controlled as '·' or 'X'. That is, according to the control of the relay of the inverter <NUM> and the relay of the capacitor unit <NUM>, the phase of the current in each coil may be controlled to <NUM> or <NUM> degrees. By controlling the phase of each coil, it is possible to generate wireless power by the magnetic flux transmitted to the upper part in the corresponding power supply line section to enter the charging mode, or to cancel the magnetic flux to cut off the power (off mode). For example, in the case of <NUM> in <FIG>, magnetic flux is generated from the current of the power supply cable <NUM>, so that the pick-up is in the charging mode. However, in the case of <NUM>, the pair of coils on the left side cancel each other out as currents of opposite phases, so that no power is generated for charging. Similarly, no power is generated on the pick-up by the pair of coils on the right.

In this way, the phase control of the current may perform various controls in addition to switching to the charging mode or the off mode. For example, in the case of <NUM> or <NUM> of <FIG>, power may be generated on the pick-up according to the distance <NUM> between the two coils even if the phases of currents in the pair of coils on the left are opposite to each other. That is, if the two coils are arranged very close to each other, little power will be generated on the pick-up, but as the distance between the two coils is more than a certain interval, the generated power on the pick-up increases. As described above, depending on the distance between the coils <NUM> and the distance between the coil <NUM> and the lower power supply core <NUM> (<NUM>, see <FIG> ), the generated power when the same phase current flows through the pair of coils on both sides and the generated power when the opposite phase current flows change to be compatible with the pickup on the pick-up.

The inverter <NUM> for controlling the magnitude and phase of the generated current turns on or off the wireless power generation of the corresponding section according to whether a vehicle is present in a specific segment of the power supply line section. In addition, by detecting the type of a pick-up device mounted on a vehicle passing through the section and the height of the pick-up that has a difference from the ground of the power supply line depending on a large vehicle or passenger car, etc., it is possible to control the phase of the current flowing in the power supply cable <NUM> (i.e., the coil <NUM> as shown in the embodiment <NUM> of <FIG> ) of the power supply line so that wireless power is supplied.

Such control of the phase of the current by the inverter <NUM> is performed by controlling the relay provided in the inverter <NUM> and the relay provided in the capacitor unit <NUM> of each section.

That is, when the power supply cable <NUM> is composed of n (n≥<NUM>) pairs of coils, each coil can independently adjust the phase of the current by a relay under the control of the inverter <NUM>. Any combination of <NUM> degree or <NUM> degree phase is possible for n pairs of coils. By controlling the current phase combination of the inverter <NUM> as described above, the wireless power supplied through the power supply cable is controlled.

As described above, for various types of pick-ups and installation heights of various pick-ups, it is 'compatibility' as described above to automatically control and supply an appropriate amount of wireless power for charging.

In addition, the inductance of the power supply line can be reduced by controlling the phase.

<FIG> is a diagram showing a distance <NUM> between the coil <NUM> and a distance <NUM> between the coil <NUM> and the ferromagnetic material <NUM> that is a power supply core, which are design variables of the wireless charging power supply system <NUM> according to the present invention. <FIG> is a graph showing a change in inductance per unit distance of a power supply line according to the design variable shown in <FIG>.

<FIG> shows a method for securing compatibility according to the interval between coils constituting the power supply line and for extending the section due to the reduction of inductance. An advantageous condition can be determined by converting an inductance value according to a change in the distance between the coils <NUM> and the distance <NUM> between the coil and the ferromagnetic material into a unit distance. That is, each coil may be disposed to contact each other without a separation distance, or may be disposed to be spaced apart from each other by a predetermined distance. The coil constituting the power supply cable and the power supply core may also be disposed to contact each other without a separation distance, or may be disposed to be spaced apart from each other by a predetermined distance.

In <FIG>, the F15 line <NUM> indicates that the separation distance <NUM> between the ferromagnetic material and the coil is <NUM>, and F25 line <NUM> indicates that the separation distance <NUM> between the ferromagnetic material and the coil is <NUM>. In addition, the value of the x-axis (horizontal axis) of the graph represents the distance <NUM> between the coils, and the y-axis (vertical axis) means inductance per unit length.

The <NUM> dots on each line in the graph show examples of a total of <NUM> designs for the design variables (<NUM>, <NUM>) of the interval, and the appropriate design variable values according to the environment and various conditions in which the power supply line is installed can be set.

<FIG> is a diagram illustrating a method of locating a portion of the common line <NUM> in the wireless charging power supply system <NUM> according to the present invention. The common line refers to a portion where the power supply cables <NUM> are gathered, that is, a portion <NUM> (refer to <FIG>) where the power supply cables are gathered from, for example, the inverter <NUM> or the capacitor unit <NUM>. The common line <NUM> is wrapped by the shielding tube <NUM> to shield the magnetic field and, as shown in <FIG>, the inductance can be reduced by maximizing the magnetic field cancellation effect by adjusting the direction of the current.

<FIG> is a flowchart illustrating a power supply control method in the wireless charging power supply system <NUM> according to the present invention. The control of <FIG> is performed by the inverter <NUM>. When the electric vehicle <NUM> equipped with a pick-up enters the power supply section controlled by the inverter <NUM>, the position of the corresponding vehicle is detected (S801). The power supply section controlled by the inverter means all the capacitor units <NUM> connected to the corresponding inverter <NUM> and the power supply cable section connected thereto. The detected location of the corresponding vehicle means in which power supply segment within the corresponding power supply section the vehicle is. The power supply segment refers to a power supply line between the inverter <NUM> and the next capacitor unit <NUM> (refer to <FIG>), and a power supply line between the next capacitor unit <NUM> (refer to <FIG>) and another next capacitor unit <NUM> (refer to <FIG>), etc. Referring to <FIG>, if the power supply line between the inverter <NUM> and the next capacitor unit <NUM> (see <FIG>) is referred to as a first power supply segment, and the power supply line between the next capacitor unit <NUM> (see <FIG> ) and another next capacitor unit <NUM> (see <FIG>) is referred to as a second power supply segment, the vehicle currently enters the second power supply segment.

Such position detection (S801) may be performed in various ways. As an embodiment, the method may be performed by receiving GPS information of the corresponding vehicle <NUM> and identifying a power supply segment within the current power supply section of the inverter <NUM>. Alternatively, the inverter <NUM> connected to the power supply segment in which the vehicle <NUM> is located may directly detect the vehicle entry, or the capacitor units <NUM> and <NUM> connected to the power supply segment may detect the vehicle entry and send a signal to the inverter <NUM>.

Thereafter, the inverter <NUM> connected to the power supply segment in which the corresponding vehicle <NUM> is located may directly detect information on the pick-up mounted on the corresponding vehicle <NUM>. Alternatively, the capacitor units <NUM> and <NUM> connected to the power supply segment may detect information on the pick-up mounted on the vehicle <NUM> and transmit the information to the inverter <NUM>, and the inverter <NUM> may determine the pick-up information (S802). The pick-up information may include a type of the pick-up, a height of the pick-up from the ground, and the like.

The inverter <NUM> switches the power supply segment in which the vehicle is located to the charging mode according to the detected pick-up information and controls the power to be supplied (S803). Such power control, as described above with reference to <FIG>, controls the phase of the current of each coil <NUM> by controlling the relay of the inverter <NUM> and the capacitor unit <NUM> or <NUM> of the corresponding power supply segment.

Afterwards, when the corresponding vehicle <NUM> leaves the power supply segment, the inverter <NUM> switches the corresponding power supply segment to an off mode to cut off the power of the corresponding power supply segment (S804). The power cut-off of the power supply segment may also be performed by controlling the relay of the capacitor unit <NUM> or <NUM> of the corresponding power supply segment to control the phase of the current of each coil <NUM>.

Claim 1:
A system (<NUM>) for controlling the wireless charging power of electric vehicles (<NUM>) in motion, comprising:
a power supply cable (<NUM>) for generating power for wireless charging by flowing an AC current;
an inverter (<NUM>) for controlling the supply of the AC current flowing through the power supply cable (<NUM>) and including a relay unit for adjusting the phase of the AC current to <NUM> degrees or <NUM> degrees; and, characterized by
one or more capacitor unit (<NUM>) including a relay for adjusting the phase of the AC current to <NUM> degrees or <NUM> degrees under the control of the inverter (<NUM>), and a capacitor (<NUM>) for offsetting the inductance of the power supply cable (<NUM>),
wherein a first part of the power supply cable (<NUM>) is connected between the inverter (<NUM>) and the capacitor unit (<NUM>) without returning to the inverter (<NUM>),
when two or more capacitor units (<NUM>) are provided, another part of the power supply cable (<NUM>) is connected between the nth capacitor unit (<NUM>) and the (n+<NUM>)th capacitor unit (<NUM>) without returning to the nth capacitor unit (<NUM>),
wherein a final part of the power supply cable (<NUM>) is connected between the last capacitor unit (<NUM>) and the inverter (<NUM>),
wherein a power supply region is made between the inverter and the capacitor unit (<NUM>) via the first part of the power supply cable and the final part of the power supply cable,
when two or more capacitor units (<NUM>) are provided, an additional power supply region is made between each capacitor units (<NUM>) via the corresponding another part of the power supply cable and the final part of the power supply cable,
wherein a final power supply region is made after the last capacitor unit (<NUM>) via the final part of the power supply cable only,
wherein each power supply region acts like a coil (<NUM>) for generating power for wireless charging.