KR20230134395A - Multilayer coil and wireless power transfer system - Google Patents

Abstract

Embodiments of the present disclosure relate to a multilayer coil and a method of controlling self-inductance or alternating current resistance of the multilayer coil, comprising: a first coil layer including a plurality of loops; and a second coil layer including at least one loop, wherein the loop included in the second coil layer is connected in series with the loop of the first coil layer to adjust at least one of the self-inductance or alternating current resistance of the multilayer coil. Alternatively, they may be connected in parallel, so that the self-inductance of the coil can be adjusted through the connection method between the loops of the multilayer coil, and the alternating current resistance of the coil can be adjusted.

Description

Multilayer coil and wireless power transmission system {MULTILAYER COIL AND WIRELESS POWER TRANSFER SYSTEM}

Embodiments of the present disclosure relate to a multilayer coil and wireless power transmission system related to wireless power transmission, and in particular, to a multilayer coil and wireless power transmission system that can adjust inductance and alternating current resistance in the transmission and reception of wireless power transmission. .

Wireless power transmission refers to a technology that supplies power to home appliances wirelessly instead of traditional wired power lines. Recently, in order to commercialize wireless charging of digital home appliances, including smartphones, research is underway on magnetic induction and magnetic resonance wireless power transmission technologies.

The magnetic induction wireless power transmission method uses the magnetic induction phenomenon between the transmitting coil and the receiving coil, and uses the magnetic field formed in the near field by the time-varying current applied to the transmitting coil. Magnetic resonance wireless power transmission is a technology that transmits power through magnetic resonance, and can transmit electrical energy with relatively high efficiency over a longer distance than the magnetic induction wireless power transmission method.

In order to match the resonance frequency in the self-resonance wireless power transmission method, the larger the coil's self-inductance, the more precise a capacitor must be used. Meanwhile, in the self-induction wireless power transmission method, the larger the self-inductance, the higher the voltage.

In high-frequency coils, not only does resistance increase due to the skin effect, in which current flows through the outer shell of a metal conductor, but also the proximity effect, in which the cross-sectional area through which the current actually flows decreases due to the magnetic field created in adjacent conductors. Resistance increases by

In wireless power transmission, self-inductance and resistance control of the transmitting and receiving coils is required to increase coupling efficiency and reduce heat generation.

Embodiments of the present disclosure can provide a multilayer coil and wireless power transmission system that can adjust inductance and alternating current resistance in wireless power transmission.

Embodiments of the present disclosure include a substrate; A first coil layer disposed on the first side of the substrate and including a plurality of loops; and a second coil layer disposed on a second side of the substrate and including at least one loop, wherein the loop included in the second coil layer is connected in series or in parallel through a loop and a via in the first coil layer. A multilayer coil can be provided.

Embodiments of the present disclosure include a wireless power transmission transmitter including a power source that supplies a time-varying current and a transmission coil that forms a time-varying magnetic flux through the time-varying current supplied from the power source; In a wireless power transmission system including a wireless power transmission receiver including a receiving coil for receiving power by time-varying magnetic flux, the transmitting coil or the receiving coil includes: a substrate; A first coil layer disposed on the first side of the substrate and including a plurality of loops; and a second coil layer disposed on a second side different from the first side of the substrate and including at least one loop, wherein the loop included in the second coil layer is connected through the loop and via of the first coil layer. A wireless power transmission system that is a multilayer coil connected in series or parallel can be provided.

According to embodiments of the present disclosure, the self-inductance of the coil used for wireless power transmission can be adjusted through a connection method between loops of the multilayer coil, and the resistance of the coil can also be adjusted. Through this, heat generation by the coil can be suppressed by lowering the high-frequency loss resistance, and the coupling efficiency between coils can also be improved.

1 is a diagram showing the configuration of a magnetically coupled wireless power transmission system according to embodiments of the present disclosure.
Figure 2 is a diagram showing an equivalent circuit of a magnetically coupled wireless power transmission system according to embodiments of the present disclosure.
Figure 3 is a diagram showing a coil and its equivalent coil structure according to embodiments of the present disclosure.
Figure 4 is a diagram showing a cross section of a spiral circular coil and a cross section of a spiral square coil according to embodiments of the present disclosure.
Figure 5 is a diagram showing current distribution according to the skin effect and proximity effect in a patterned coil according to embodiments of the present disclosure.
FIGS. 6A to 6F are diagrams showing examples of loop arrangements of multilayer coils according to embodiments of the present disclosure.
Figure 7 is a diagram showing an example of a connection relationship between loops belonging to different layers according to embodiments of the present disclosure.
Figure 8 is a diagram showing an example of a connection relationship between loops belonging to the same layer according to embodiments of the present disclosure.
9 is a diagram illustrating an example of coil loop arrangement according to embodiments of the present disclosure.

Hereinafter, some embodiments of the present disclosure will be described in detail with reference to illustrative drawings. In adding reference numerals to components in each drawing, the same components may have the same reference numerals as much as possible even if they are shown in different drawings. Additionally, in describing the present disclosure, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present disclosure, the detailed description may be omitted. When “comprises,” “has,” “consists of,” etc. mentioned in the specification are used, other parts may be added unless “only” is used. When a component is expressed in the singular, it can also include the plural, unless specifically stated otherwise.

Additionally, in describing the components of the present disclosure, terms such as first, second, A, B, (a), and (b) may be used. These terms are only used to distinguish the component from other components, and the nature, sequence, order, or number of the components are not limited by the term.

In the description of the positional relationship of components, when two or more components are described as being “connected,” “coupled,” or “connected,” the two or more components are directly “connected,” “coupled,” or “connected.” ", but it should be understood that two or more components and other components may be further "interposed" and "connected," "combined," or "connected." Here, other components may be included in one or more of two or more components that are “connected,” “coupled,” or “connected” to each other.

In the description of temporal flow relationships related to components, operation methods, production methods, etc., for example, temporal precedence relationships such as “after”, “after”, “after”, “before”, etc. Or, when a sequential relationship is described, non-continuous cases may be included unless “immediately” or “directly” is used.

On the other hand, when a numerical value or corresponding information (e.g., level, etc.) for a component is mentioned, even if there is no separate explicit description, the numerical value or corresponding information is related to various factors (e.g., process factors, internal or external shocks, It can be interpreted as including the error range that may occur due to noise, etc.).

Hereinafter, various embodiments of the present disclosure will be described in detail with reference to the attached drawings.

1 is a diagram showing the configuration of a magnetically coupled wireless power transmission system according to embodiments of the present disclosure.

Referring to FIG. 1, the magnetically coupled wireless power transmission system includes a wireless power transmission transmitter including a transmitting coil 110 and a power source 120, and a wireless power transmission receiver including a receiving coil 130 and a load 140. It can be included.

Recently, the application areas for magnetically coupled wireless power transmission technology are increasing, and the International Wireless Power Consortium (WPC) announced version 1.3 of Qi, the international standard for smartphone wireless charging.

Magnetic coupling wireless power transmission technology is based on magnetic induction. The magnetic induction wireless power transmission method supports one receiver for one transmitter, and the transmission distance of the transceiver may be relatively small.

Meanwhile, in self-resonant wireless power transmission technology, the wireless power transmission transmitter and wireless power transmission receiver use the same resonance frequency. Self-resonant wireless power transmission technology has a coupling coefficient (coupling coefficient) between the wireless power transmission transmitter and the wireless power transmission receiver. , MPS is the mutual inductance of the transmitting coil 110 included in the wireless power transmission transmitter and the receiving coil 130 included in the wireless power transmission receiver, LP is the self-inductance of the transmitting coil 110, and LS is the receiving coil 130. Even if the self-inductance is low, the efficiency does not drop sharply, so the power transmission distance can be relatively larger compared to magnetic induction wireless power transmission technology.

The magnetic induction wireless power transmission method for smartphone wireless charging can use frequencies of 100kHz to 205kHz, and generally can use Litz wire to improve efficiency. Litz wire is a conductor made by bundled very thin metal conductors according to rules, and can greatly reduce the resistance of the coil at the frequency of use.

Meanwhile, magnetic coupling can also be used in short-distance wireless communication using magnetic fields, such as NFC (Near Field Communication).

In wireless power transmission and wireless communication using magnetic coupling, the transmission distance can be improved by increasing the magnetic field created in the coil. Additionally, reception sensitivity can be improved. For this purpose, the shape of the transmitting coil 110 or the receiving coil 130 may be a spiral structure having a plurality of turns.

The power source 120 generates an alternating current signal, which is a time-varying current, and transmits it to the transmission coil 110. The transmitting coil 110 forms a time-varying magnetic flux through an alternating current signal, which is a time-varying current. In accordance with Faraday's law, an induced electromotive force is formed in the receiving coil 130. That is, the receiving coil 130 receives power from the transmitting coil by an electromagnetic induction phenomenon. The receiving coil that receives power by time-varying magnetic flux transfers the received electrical energy to the load 140.

Figure 2 is a diagram showing an equivalent circuit of a magnetically coupled wireless power transmission system according to embodiments of the present disclosure.

The transmitting coil 110 can be represented by a resistance (RP), a capacitor for resonance (CP), and a self-inductance (LP) of the coil. The receiving coil 130 can also be represented by a resistance (RS), a capacitor for resonance (CS), and a self-inductance (LS) of the coil.

At this time, the voltage (VP) induced in the transmitting coil 110 can be expressed by Equation 1, and the voltage (VS) induced in the receiving coil 130 can be expressed by Equation 2.

According to Equation 1 and Equation 2, when the voltage due to mutual inductance (MPS) is large, the voltages (VP, VS) induced in the transmitting coil 110 and the receiving coil 130 may increase. At this time, ω refers to the angular velocity.

In addition, according to Equation 1 and Equation 2, when matching the resonance frequency using capacitors (CP, CS) in the self-resonance method, as the self-inductance of the transmitting coil 110 and the receiving coil 130 increases, A capacitor with precise capacity is required.

Meanwhile, in the self-coupled wireless power transmission method, the maximum coupling efficiency is obtained by Equation 3 through the resistance (RP, RS) and mutual inductance between the transmitting coil 110 and the receiving coil 130 under the condition that the load and the transmitting unit are matched. It can be defined.

η is the maximum coupling efficiency of the wireless power transmission system, and FoM is the Figure of Merit of the wireless power transmission system.

According to Equation 3, in order to increase the maximum coupling efficiency (η) of the wireless power transmission system, the figure of merit (FoM) of the wireless power transmission system must be large. The figure of merit (FoM) of the wireless power transmission system may be determined according to the resistance (RP, RS) and mutual inductance (MPS) of the transmitting coil 110 and the receiving coil 130. Referring to Equation 3, in order to increase the figure of merit (FoM) of the wireless power transmission system, the resistances (RP, RS) of the transmitting coil 110 and the receiving coil 130 are reduced, and the transmitting coil 110 and the receiving coil 130 are reduced. The mutual inductance (MPS) between the coils 130 can be increased.

Figure 3 is a diagram showing a coil and its equivalent coil structure according to embodiments of the present disclosure.

The coil 310 may have a circular spiral coil structure. The circular spiral coil may have a shape wound in a circle around the center of the coil. Meanwhile, unlike shown in FIG. 3, the coil 310 may have a square spiral shape.

The equivalent coil structure 320 is a structure in which several loops are wound concentrically around the center of the coil. The coil 310 and the coil equivalent structure 320 can be used for analysis of the coil 310, and have a shape wound into several circles around the center of the coil. The equivalent structure of the coil 320 has the same characteristics as the coil 310. The wire used in coil 310 may be a metal conductor, as well as a Litz wire or a printed pattern on a substrate (e.g., a printed circuit board).

Figure 4 is a diagram showing a cross section of a spiral circular coil and a cross section of a spiral square coil according to embodiments of the present disclosure.

The coils 410 and 420 shown in FIG. 4 may be a printed pattern of a printed circuit board.

The magnetic fields of the coils 410 and 420 may be determined by the shape of the coil. For example, if the number of turns of the coils 410 and 420 is large and the size of the coils 410 and 420 is large, the self-inductance of the coils 410 and 420 may increase. However, as the number of turns of the coils 410 and 420 increases, loss resistance may increase. Therefore, the figure of merit (FoM) of the wireless power transmission system may deteriorate.

Meanwhile, in alternating current in the high frequency band, resistance may increase due to the skin effect, in which current flows to the outer shell of a metal conductor. Additionally, resistance may increase due to the proximity effect, in which the actual cross-sectional area of the current flowing in the coil is reduced by the magnetic field created by adjacent conductors.

Figure 5 is a diagram showing current distribution according to the skin effect and proximity effect in a patterned coil according to embodiments of the present disclosure.

Referring to FIG. 5, the patterned coil 510 can be confirmed to have an equivalent configuration of a circular spiral conductor having three turns. The thickness (H) of the metal pattern of the patterned coil 510 is 0.2 mm, the gap between loops is 1 mm, the width of the pattern is 0.4 mm, and the radius of the outermost pattern is 40 mm. The frequency of alternating current is 6.78Mhz.

If you check the current distribution of the a loop, b loop, and c loop, you can see that almost no current flows in the center, but the current flows concentrated in the outer corners. .

In the b loop, the current distribution is close to left-right symmetry, but in the a loop, the current distribution is concentrated in the left corner, and in the c loop, the current distribution is concentrated in the right corner. In the b loop, the influence of the magnetic field from the a loop and c loop is applied equally, and resistance mainly occurs due to the skin effect.

On the other hand, in the a loop and c loop, the effective area where the current flows decreases due to the proximity effect due to the eddy current created when the magnetic field created by the current flowing from another neighboring conductor is applied to the loop. In coil design, resistance is inversely proportional to the unit area through which current flows and is proportional to length, so it is important to reduce coil loss resistance by making the area through which current flows as wide as possible.

FIGS. 6A to 6F are diagrams showing examples of loop arrangements of multilayer coils according to embodiments of the present disclosure.

Referring to FIG. 6A, the multilayer coil 600 is disposed on a printed circuit board 630, a first surface of the printed circuit board 630, and includes a first coil layer 610 including a plurality of loops, and a multilayer coil ( 600) is disposed on a second side different from the first side of the printed circuit board 630 to adjust at least one of the self-inductance or alternating current resistance, and is connected through the loop and via 640 of the first coil layer 610. It may include a second coil layer 620 including one or more loops connected in series or in parallel (P).

The multilayer coil 600 may consist of a loop of multiple layers, and each loop may be connected in series or in parallel. The self-inductance value can be lowered by configuring the loops included in the multilayer coil 600 as parallel loops, and the self-inductance can be increased by configuring the loops included in the multilayer coil 600 as a series loop.

When the loops included in the multilayer coil 600 are connected in parallel, the two metal patterns are combined to have the same characteristics as a single pattern. This has the effect of allowing the same characteristics to be obtained by manufacturing the metal pattern separately when the thickness of the single pattern is very thick and it is difficult to manufacture it by general methods. Meanwhile, when the loops included in the multilayer coil 600 are connected in series, each loop acts as one turn, which has the effect of increasing the number of turns.

The multilayer coil 600 can be configured in series or parallel connection between loops of the same layer, as well as between loops of different layers or in a mixed form of the two.

To adjust the resistance of the multilayer coil 600, loops connected in parallel can be added. In particular, in order to reduce the resistance of the multilayer coil 600, a loop connected in parallel to the loop at the portion with the largest resistance component due to the proximity effect, that is, the outermost loop or the innermost loop, can be added. Through this, for the same current, the resistance can be lowered by increasing the cross-sectional area through which the current flows.

Meanwhile, according to an embodiment of the present disclosure, the magnetic field strength of the multilayer coil 600 can be adjusted by configuring additional loops in series or parallel.

For example, in order to increase the strength of the magnetic field at the center of the multilayer coil 600, loops near the center may be additionally connected in series.

Additionally, the position of the multilayer coil 600 can be adjusted so that the multilayer coil 600 can have a uniform magnetic field. Additionally, the strength of the magnetic field can be adjusted by connecting vertically configured loops in series or parallel. Through this, the mutual inductance of the transmitting coil and receiving coil of the wireless power transmission system can be adjusted, and the voltage induced in the transmitting coil and receiving coil can also be adjusted.

The mutual inductance of the wireless power transmission system depends on the sum of the magnetic flux induced in the receiving coil for each single loop constituting the transmitting coil. At this time, in the case of multiple loops connected in parallel, the number of turns can be treated as one. In a structure in which the loops constituting the transmitting coil and the receiving coil are connected in series, the mutual inductance increases, and in the structure in which the loops constituting the transmitting coil and the receiving coil are connected in parallel, the mutual inductance does not increase relatively significantly compared to the serial connection.

Meanwhile, as described above, the multilayer structure of the multilayer coil 600 can be implemented through the printed circuit board 630. For example, when a plurality of loops arranged on different layers are connected vertically, they can be easily connected in series or parallel through vias.

The first coil layer 610 and the second coil layer 620 of the multilayer coil 600 may be disposed on the first and second surfaces of the printed circuit board 630. A first coil layer 610a may be formed on the upper surface of the printed circuit board 630a, and a second coil layer 610b may be formed on the lower surface of the printed circuit board 630a. In addition, a multilayer printed circuit board ( A first coil layer 610b may be formed on the upper surface of 630b), and a second coil layer 620b may be formed inside the printed circuit board 630b. This is just an example in which the first coil layer 610 and the second coil layer 620 are disposed on the printed circuit board 630, and the first coil layer 610 and the second coil layer 620 are printed circuit boards. It can be placed on the substrate in various ways.

The printed circuit board 630 is made of paper phenol, paper epoxy, paper polyester, polyester film, polyimide film, ceramic, oxidation Anodized aluminum, Teflon, ceramic, etc. can be used. The loop-in pattern of the printed circuit board 630 can be made of metal or conductive materials such as copper, gold, silver, and aluminum. .

(A) to (H) disclosed in FIGS. 6B to 6F represent embodiments of the multilayer coil 600.

(A) of FIG. 6B shows that all loops of the first coil layer 610 and the second coil layer 620 of the multilayer coil 600 are connected in series. The same current I1 flows in the same direction (for example, a direction perpendicular to the plane) through the plurality of loops included in the first coil layer 610 and the second coil layer 620. This connection structure can increase self-inductance by more than four times compared to a loop consisting of only the first coil layer 610. Meanwhile, the loops of the second coil layer 620 can be added or excluded as much as the target self-inductance of the multi-layer coil 600 to adjust the self-inductance of the multi-layer coil 600. The first coil layer 610 and the second coil layer 620 may be disposed on a printed circuit board 630 and may be vertically connected between coil layers through a via 640. This is just an example in which all loops included in the first coil layer 610 and the second coil layer 620 are connected in series, and may be connected in series through a connection method different from that shown in FIG. 6B.

(B) of FIG. 6C shows parallel connection between the upper and lower loops of the first coil layer 610 and the second coil layer 620 of the multilayer coil 600. Referring to (B) of FIG. 6C, a plurality of loops included in the second coil layer may be connected in parallel to correspond to a plurality of loops included in the first coil layer.

When the corresponding loops of the first coil layer 610 and the second coil layer 620 are connected in parallel, one loop of the first coil layer 610 and the corresponding loop of the second coil layer 620 are used as a whole. Current I1 flows in the same direction. Meanwhile, current may flow differently between parallel connected loops depending on the impedance of the individual loops. The connection method according to (B) of FIG. 6C can be used to reduce alternating current resistance occurring in the conductors of the multilayer coil 600 in the high frequency band of the megahertz level or lower. For example, assuming that the 6.78Mhz frequency is used, in order to lower the resistance of the coil, the thickness of the metal conductor constituting the loop, especially when using the printed circuit board 630, the thickness of the pattern must be 3 to 4 ounces (Oz). It is desirable to form it as If the thickness of the pattern of the printed circuit board 630 is small, the resistance due to the skin effect increases rapidly, thereby increasing the loss resistance of the entire coil, which may cause loss in power transmission efficiency as well as heat generation in the wireless power transmission system. Meanwhile, in the case of the printed circuit board 630, it can generally be easily manufactured up to 2 ounces, but in cases larger than that, pattern manufacturing is limited. Therefore, when a 2-ounce pattern is made on both sides of the printed circuit board 630 as shown in (B) of FIG. 6C, and the upper and lower loops of the printed circuit board 630 are connected in parallel, the thickness of the multilayer coil 600 is 2. You can achieve a doubling of resistance improvement effect. Meanwhile, the resistance of the multilayer coil 600 may be adjusted by adjusting the number of loops connected to the second coil layer 620 in parallel with the loops of the first coil layer.

The first coil layer 610 and the second coil layer 620 may be disposed on a printed circuit board 630, and the coil layers may be connected through a via 640.

(C) of FIG. 6D uses only a portion of the loops of the second coil layer 620, and each loop of the second coil layer 620 is connected in series or parallel with the loop of the first coil layer 610. indicates.

According to (C) of FIG. 6D, the first coil layer 610 and the second coil layer 620 are disposed on the printed circuit board 630. At this time, the strength of the magnetic field of the multilayer coil 600 can be increased through a portion connected in series between the loops of the first coil layer 610, and the first coil layer 610 is formed in the outermost loop and the innermost loop. and the portion connected in parallel through the via 640 between the second coil layer 620 can lower the alternating current resistance component of the multilayer coil 600.

According to (D) of FIG. 6E, the innermost loop and outermost loop of the first coil layer 610 of the multilayer coil 600 and the loop of the second coil layer 620 are connected in parallel, and the first coil layer The inner loop of 610 is connected in series with the loop of the second coil layer 620. As described above in FIG. 5, the current distribution is generally biased toward the edge due to the proximity effect in the outermost loop and innermost loop of the coil, thereby greatly reducing the area through which the current flows. At this time, the innermost loop and the outermost loop of the first coil layer 610 can be connected in parallel with the loop of the second coil layer 620 to lower the resistance. On the other hand, since the influence of the proximity effect is relatively small in the conductor corresponding to the center of the loop, the self-inductance can be increased by connecting the loop of the first coil layer 610 and the loop of the second coil layer 620 in series. there is. At this time, in order to adjust the self-inductance of the multilayer coil 600, the number of loops of the second coil layer 620 connected in series with the first coil layer 610 can be adjusted.

In (E) of FIG. 6F, the outermost loop of the loop of the first coil layer 610 and the loop of the second coil layer 620 can be connected in parallel to lower the resistance of the multilayer coil 600. Additionally, other loops of the second coil layer 620 may be disposed at positions that do not coincide with the loops of the first coil layer 610. Through this, the magnetic field of the multilayer coil 600 can be adjusted to adjust the mutual inductance between the transmitting coil and the receiving coil, or the self-inductance of the multilayer coil 600 can be adjusted.

(F) of FIG. 6F shows that some of the loops of the second coil layer 620 are disposed at positions matching the loops of the first coil layer 610, and some do not match the loops of the first coil layer 610. It can be placed in a location that is not available. Through this, the mutual inductance between the transmitting coil and the receiving coil can be improved.

In (G) of FIG. 6F, two or more loops of the first coil layer 610 and loops of the second coil layer 620 may be connected in parallel. Through this, the self-inductance of the multilayer coil 600 can be lowered, and the magnetic field intensity can also be adjusted to lower. In particular, the external influence of the magnetic field generated from the multilayer coil 600 can be reduced by adjusting the strength of the magnetic field.

In (H) of FIG. 6F, in the embodiment of (E), the outermost loop of the first coil layer 610 and the outermost loop of the second coil layer 620 are connected in series, and the first coil layer 610 It represents a structure in which the outermost loop and the adjacent loop are connected in parallel. Through this, the shape of the magnetic field formed in the multilayer coil 600 can be improved.

Through the above-described example, even if the quality factor (ωL/R), which is defined as the ratio of the coil's self-inductance and loss resistance, is the same, various multilayer coil 600 designs are possible.

For example, when low resistance is required compared to the self-inductance of the coil in the wireless power transmission system, the loops of the first coil layer 610 and the second coil layer 620 are configured in parallel to form the multilayer coil 600. Resistance can be lowered.

Conversely, when high self-inductance is required compared to resistance, self-inductance can be increased by connecting loops of the first coil layer 610 and the second coil layer 620 in series. Additionally, in order to match self-inductance and loss resistance, the loops of the first coil layer 610 and the second coil layer 620 may be mixed and connected in series or parallel.

Additionally, in order to increase the mutual inductance of the coils in the wireless power transmission system, loops connected in series may be added to the second coil layer 620. When a loop connected in series to the multilayer coil 600 is added, the strength of the magnetic field generated by the multilayer coil 600 increases, and thus the mutual inductance may also increase. If mutual inductance is increased by additionally arranging loops connected in series to the multilayer coil 600, and loops connected in parallel are also arranged to minimize the increase in loss resistance, the coupling efficiency of the wireless power transmission system can be increased.

Meanwhile, the multilayer coil may further include not only the first coil layer 610 and the second coil layer 620, but also an additional coil layer (not shown). At this time, the first coil layer 610 is on the top of the printed circuit board 630, the second coil layer 620 is on the inside of the printed circuit board 630, and the additional third coil layer is on the printed circuit board 630. ) may be disposed on the lower surface of the loop. The loops of the first to third coil layers 610 may be connected through the method described above.

Meanwhile, (A) to (G) of FIGS. 6B to 6F are exemplary, and the loop configuration of the second coil layer 620 and the loop between the first coil layer 610 and the second coil layer 620 or The connection relationship between additional coil layers is not limited to the above-described example, and various methods may be used.

Figure 7 is a diagram showing an example of a connection relationship between loops belonging to different layers according to embodiments of the present disclosure.

Referring to FIG. 7, loops of the first coil layer 710 and the second coil layer 720 may be connected in series or in parallel.

Referring to (A) of FIG. 7, the current I1 is input to the first coil layer 710, and the current I1 flows from the first loop LP1 of the first coil layer 710 to the second coil layer 720. It may be transmitted to the second loop LP2, and from the second loop LP2 of the second coil layer 720 to the third loop LP3 of the first coil layer 710. At this time, when the loops of the first coil layer 710 and the second coil layer 720 are patterns on the printed circuit board, the via 740 of the printed circuit board is between the first loop (LP1) and the second loop (LP2). ) can be connected through. The second loop LP2 and the third loop LP3 may also be connected through the via 740 of the printed circuit board 730. Through this, the first loop (LP1), the third loop (LP3) of the first coil layer 710, and the second loop (LP2) of the second coil layer 720 may be connected in series.

Referring to (B) of FIG. 7 , the fourth loop LP4 of the first coil layer 710 and the fifth loop LP5 of the second coil layer 720 may be connected in parallel. Current I1 is input to the first coil layer 710, and the current I1 can be divided into the fourth loop LP4 of the first coil layer 710 and the fifth loop LP5 of the second coil layer 720. . The sum of the current Ia flowing in the fourth loop LP4 and the current Ib flowing in the fifth loop LP5 may be the current I1 input to the first coil layer 710. Current Ia and current Ib may flow separately depending on the impedance of the fourth loop (LP4) and the fifth loop (LP5). Meanwhile, when the loops of the first coil layer 710 and the second coil layer 720 are patterns on the printed circuit board 730, the space between the fourth loop LP4 and the fifth loop LP5 is a printed circuit board ( It can be connected through the via 740 of 730). Through this, the fourth loop LP4 of the first coil layer 710 and the fifth loop LP5 of the second coil layer 720 may be connected in series.

Figure 8 is a diagram showing an example of a connection relationship between loops belonging to the same layer according to embodiments of the present disclosure.

Referring to FIG. 8, loops of the same layer may be connected in series or in parallel.

Referring to (A) of FIG. 8, the current I1 input to the coil may be transmitted to the seventh loop LP7 through the sixth loop LP6. At this time, the same value of current may flow through the sixth loop (LP6) and the seventh loop (LP7).

Referring to (B) of FIG. 8, the current I1 input to the coil may flow divided into the eighth loop (LP8) and the ninth loop (LP9) connected in parallel. At this time, the current Ic flowing in the eighth loop LP8 and the current Id flowing in the ninth loop LP9 can be divided according to the impedance of each loop.

9 is a diagram illustrating an example of coil loop arrangement according to embodiments of the present disclosure.

Referring to FIG. 9, the multilayer coil 900 is disposed on a different plane from the first coil layer 910 and the first coil layer 910, and is in series with the loop of the first coil layer 910 at a specific position. It may include a second coil layer 920 to which a connected loop is added. Loops included in the second coil layer 920 may be arranged based on different centers. At this time, the strength of the magnetic field formed in a specific part of the multilayer coil 900 increases due to the loops included in the second coil layer 920, and through this, mutual inductance with other coils can be increased.

Through the multilayer coil shown in FIGS. 6A to 9, the self-inductance of the coil of the wireless power transmission system can be increased or decreased, and the loss resistance due to high-frequency alternating current can also be reduced. By lowering the loss resistance, the resulting heat generation can be suppressed, and the coupling efficiency of the wireless power transmission system can be greatly improved.

Additionally, according to embodiments according to the present disclosure, the magnetic field of the wireless power transmission system may be adjusted to increase or decrease. When the magnetic field of the wireless power transmission system is increased, the mutual inductance will increase, thereby increasing the coupling efficiency between the transmitting coil and the receiving coil. In addition, as the mutual inductance increases, the induced electromotive force due to electromagnetic induction phenomenon increases, and the loss in the rectifier circuit can also be reduced.

In addition, the parallel configuration according to the multi-layer structure of the coil can have the effect of increasing the thickness of the metal conductor, thereby lowering the loss resistance of the coil and improving the efficiency of the wireless power transmission system.

The embodiments of the present disclosure described above are briefly described as follows.

According to the multilayer coil according to embodiments according to the present disclosure, a printed circuit board, a first coil layer disposed on the first side of the printed circuit board and including a plurality of loops, and a first coil layer different from the first side of the printed circuit board. It is disposed on two sides and may include a second coil layer including at least one loop. The loops included in the second coil layer may be connected in series or in parallel through the loops and vias in the first coil layer.

According to the multilayer coil according to embodiments of the present disclosure, a plurality of loops included in the second coil layer may be connected in parallel to correspond to a plurality of loops included in the first coil layer.

According to the multilayer coil according to embodiments according to the present disclosure, at least some of the plurality of loops included in the first coil layer may be connected in parallel or in series.

According to the multilayer coil according to embodiments of the present disclosure, at least one of the loops included in the second coil layer may be connected in parallel with the innermost loop or the outermost loop of the first coil layer.

According to the multilayer coil according to embodiments of the present disclosure, at least one of the loops of the second coil layer may be arranged not to match the loop of the first coil layer.

According to the multilayer coil according to embodiments of the present disclosure, two or more loops included in the first coil layer and one or more loops included in the second coil layer may be connected in parallel.

According to the multilayer coil according to embodiments of the present disclosure, the first coil layer and the second coil layer may be in the form of a spiral coil.

According to the multilayer coil according to embodiments of the present disclosure, a plurality of loops included in the second coil layer may be formed based on at least two centers.

According to the wireless power transmission system according to embodiments of the present disclosure, a wireless power transmission transmitter including a power source that supplies a time-varying current and a transmission coil that forms a time-varying magnetic flux through the time-varying current supplied from the power source, the time-varying magnetic flux It may include a wireless power transmission receiver including a receiving coil that receives power.

At this time, the transmitting coil or the receiving coil is disposed on a printed circuit board, a first side of the printed circuit board, a first coil layer including a plurality of loops, and a second side different from the first side of the printed circuit board, It may include a second coil layer including at least one loop. The loops included in the second coil layer may be connected in series or in parallel through the loops and vias in the first coil layer.

According to the wireless power transmission system according to embodiments of the present disclosure, a plurality of loops included in the second coil layer may be connected in parallel to correspond to a plurality of loops included in the first coil layer.

According to the wireless power transmission system according to embodiments of the present disclosure, at least some of the plurality of loops included in the first coil layer may be connected in parallel or in series.

According to the wireless power transmission system according to embodiments of the present disclosure, at least one of the loops included in the second coil layer may be connected in parallel with the innermost loop or the outermost loop of the first coil layer.

According to the wireless power transmission system according to embodiments of the present disclosure, at least one of the loops of the second coil layer may be arranged not to match the loop of the first coil layer.

According to the wireless power transmission system according to embodiments of the present disclosure, two or more loops included in the first coil layer and one or more loops included in the second coil layer may be connected in parallel.

According to the wireless power transmission system according to embodiments of the present disclosure, the first coil layer and the second coil layer may be in the form of a spiral coil.

According to the wireless power transmission system according to embodiments of the present disclosure, a plurality of loops included in the second coil layer may be formed based on at least two centers.

The above description is merely an illustrative explanation of the technical idea of the present disclosure, and those skilled in the art will be able to make various modifications and variations without departing from the essential characteristics of the present disclosure. In addition, the embodiments disclosed in the present disclosure are not intended to limit the technical idea of the present disclosure, but rather are for explanation, and therefore the scope of the technical idea of the present disclosure is not limited by these embodiments. The scope of protection of this disclosure should be interpreted in accordance with the claims below, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of rights of this disclosure.

100: wireless power transmission system 110: transmission coil
120: power source 130: receiving coil
140: load

Claims (16)

Board;
a first coil layer disposed on the first surface of the substrate and including a plurality of loops; and
A second coil layer is disposed on a second side of the substrate different from the first side and includes at least one loop,
A multilayer coil in which the loop included in the second coil layer is connected in series or in parallel through a loop and a via in the first coil layer.
According to paragraph 1,
A multilayer coil in which a plurality of loops included in the second coil layer are connected in parallel to correspond to a plurality of loops included in the first coil layer.
According to paragraph 1,
A multilayer coil in which at least some of the plurality of loops included in the first coil layer are connected in parallel or in series.
According to paragraph 1,
A multilayer coil wherein at least one of the loops included in the second coil layer is connected in parallel with an innermost loop or an outermost loop of the first coil layer.
According to paragraph 1,
A multilayer coil wherein at least one of the loops of the second coil layer is arranged not to coincide with a loop of the first coil layer.
According to paragraph 1,
A multilayer coil in which two or more loops included in the first coil layer and one or more loops included in the second coil layer are connected in parallel.
According to paragraph 1,
The first coil layer and the second coil layer are a multilayer coil in the form of a spiral coil.
According to paragraph 1,
A multilayer coil in which a plurality of loops included in the second coil layer are formed based on at least two centers.
A wireless power transmission transmitter including a power source that supplies a time-varying current and a transmitting coil that forms a time-varying magnetic flux through the time-varying current supplied from the power source;
In a wireless power transmission system including a wireless power transmission receiver including a receiving coil for receiving power by the time-varying magnetic flux,
The transmitting coil or the receiving coil is,
Board;
a first coil layer disposed on the first surface of the substrate and including a plurality of loops; and
A second coil layer is disposed on a second side of the substrate different from the first side and includes at least one loop,
A wireless power transmission system in which the loop included in the second coil layer is a multilayer coil connected in series or parallel through a loop and a via in the first coil layer.
According to clause 9,
A wireless power transmission system in which a plurality of loops included in the second coil layer are connected in parallel to correspond to a plurality of loops included in the first coil layer.
According to clause 9,
A wireless power transmission system in which at least some of the plurality of loops included in the first coil layer are connected in parallel or in series.
According to clause 9,
A wireless power transmission system in which at least one of the loops included in the second coil layer is connected in parallel with an innermost loop or an outermost loop of the first coil layer.
According to clause 9,
A wireless power transmission system wherein at least one of the loops of the second coil layer is arranged not to match the loop of the first coil layer.
According to clause 9,
A wireless power transmission system in which two or more loops included in the first coil layer and one or more loops included in the second coil layer are connected in parallel.
According to clause 9,
The first coil layer and the second coil layer are in the form of a spiral coil.
According to clause 9,
A wireless power transmission system in which a plurality of loops included in the second coil layer are formed based on at least two centers.

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