JP7266968B2 - Contactless power transmission device and contactless power transmission system - Google Patents

Description

The present disclosure relates to contactless power transmission technology with a variable inter-coil distance.

A non-contact power transmission technology with a variable distance between coils is applied for the purpose of non-contact power transmission from a door mounting portion to a door electric lock or a door lighting fixture (for example, see Patent Document 1, etc.). .

JP 2017-115442 A

By the way, the inductance of the coil on the power transmission/reception side and the capacitance of the capacitor on the power transmission/reception side are designed so that the resonance condition at the power transmission frequency is satisfied and the power transmission efficiency is increased when the distance between the coils is separated to some extent. Here, when the distance between the coils approaches approximately 0, the interlinking magnetic flux from the core on one side to the coil on the other side becomes larger than when the distance between the coils is relatively large. The inductance of the coil increases. Therefore, when the inter-coil distance is close to 0, unlike the case where the inter-coil distance is a certain distance, the resonance condition at the power transmission frequency cannot be satisfied and the power transmission efficiency cannot be increased.

Therefore, in order to solve the above problems, the present disclosure relates to a non-contact power transmission technology in which the inter-coil distance is variable, even when the inter-coil distance is nearly zero, the state where the inter-coil distance is separated to some extent. A similar object is to satisfy the resonance condition at the power transmission frequency and increase the power transmission efficiency.

In order to solve the above problem, a non-magnetic conductor is arranged in the space where the coils face each other. Then, part of the magnetic flux linkage from the core on one side to the coil on the other side is canceled by eddy current generation in the non-magnetic conductor. Therefore, even when the inter-coil distance is close to 0, the interlinking magnetic flux from the core on one side to the coil on the other side hardly changes, compared to the state where the inter-coil distance is somewhat long. The inductance of the coil also hardly changes.

Specifically, the present disclosure is a non-contact power transmission coil that includes windings and a core, and further includes a non-magnetic conductor in a space facing the non-contact power transmission coil on the other side. It is a contact power transmission coil.

According to this configuration, in the non-contact power transmission technology in which the distance between the coils is variable, even when the distance between the coils is close to 0, resonance at the power transmission frequency is generated in the same manner as when the distance between the coils is separated to some extent. It is possible to satisfy the conditions and increase the power transmission efficiency.

Further, according to the present disclosure, a contactless power transmission device is provided with the contactless power transmission coil described above on both a power transmission side and a power receiving side, and wherein the non-magnetic conductor is arranged near the core. is.

According to this configuration, part of the magnetic flux linkage from the core on the power transmission side/power receiving side to the coil on the power receiving side/power transmission side is canceled by eddy current generation in the non-magnetic conductor. Therefore, even when the distance between the coils is close to 0, the flux linkage from the core on the power transmission/reception side to the coil on the power reception/transmission side changes little compared to when the distance between the coils is somewhat large. and the inductance of the receiving side/transmitting side coils hardly changes. Even when the inter-coil distance is close to 0, the power transmission efficiency can be increased by satisfying the resonance conditions on the power transmitting side and the power receiving side at the power transmission frequency, as in the case where the inter-coil distance is a certain distance away.

Further, according to the present disclosure, the non-contact power transmission coil described above is provided not on the power transmission side but on the power reception side, and the non-magnetic conductor is arranged near the core. It is a transmission device.

According to this configuration, part of the magnetic flux linkage from the core on the power receiving side to the coil on the power transmitting side is canceled by eddy current generation in the non-magnetic conductor. Therefore, even when the inter-coil distance is close to 0, the interlinking magnetic flux from the core on the power receiving side to the coil on the power transmitting side hardly changes compared to the state where the distance between the coils is somewhat long. The inductance of the coil also hardly changes. Then, even when the inter-coil distance is close to 0, it is possible to satisfy the resonance condition on the power transmission side at the power transmission frequency and increase the power transmission efficiency, as in the case where the inter-coil distance is a certain distance away. Even if the inductance of the coil on the power receiving side changes slightly, the resonance Q value on the power receiving side is small due to the presence of the load on the power receiving side, so the resonance condition on the power receiving side at the power transmission frequency is substantially satisfied. Also, since no non-magnetic conductor is arranged on the power transmission side, eddy current loss on the power transmission side is reduced.

Further, the present disclosure is characterized in that the contactless power transmission coil described above is provided on the power transmission side and/or the power reception side, and the non-magnetic conductor is installed in a housing fixing the core. It is a contactless power transmission device.

According to this configuration, part of the magnetic flux linkage from the core on the power transmission side/power receiving side to the coil on the power receiving side/power transmission side is canceled by eddy current generation in the non-magnetic conductor. Therefore, even when the distance between the coils is close to 0, the flux linkage from the core on the power transmission/reception side to the coil on the power reception/transmission side changes little compared to when the distance between the coils is somewhat large. and the inductance of the receiving side/transmitting side coils hardly changes. Even when the inter-coil distance is close to 0, the power transmission efficiency can be increased by satisfying the resonance conditions on the power transmitting side and the power receiving side at the power transmission frequency, as in the case where the inter-coil distance is a certain distance away. In addition, since the non-magnetic conductor is arranged in the space facing the power transmission and reception sides, the eddy current loss on the power transmission side and the power reception side is reduced.

In addition, the present disclosure is characterized in that the inductance of the non-contact power transmission coil on the other side with respect to the non-contact power transmission coil described above does not depend on the distance between the coils within the range in which non-contact power transmission is possible. It is a contactless power transmission device.

According to this configuration, even when the distance between the coils approaches approximately 0, the power transmission efficiency satisfies the resonance condition on the power transmission side and/or the power reception side at the power transmission frequency, as in the case where the distance between the coils is somewhat distant. can be raised.

Further, the present disclosure includes the contactless power transmission device described above and a power transmission inverter, the input impedance seen from the power transmission inverter is inductive, and the contactless power transmission between the power transmission side and the power reception side is inductive. The contactless power transmission system is characterized in that power transmission is performed by the SS (Series-Series) method.

According to this configuration, in the non-contact power transmission technology in which the distance between the coils is variable, even when the distance between the coils is close to 0, resonance at the power transmission frequency is generated in the same manner as when the distance between the coils is separated to some extent. It is possible to satisfy the conditions and increase the power transmission efficiency.

By the way, as shown in FIGS. 8 to 10, it is desirable that the input impedance seen from the power transmission inverter is slightly inductive. Here, when the distance between the coils approaches approximately 0, compared to when the distance between the coils is somewhat large, when the inductivity of the input impedance seen from the power transmission inverter becomes too large, the power transmission inverter cannot operate stably. In addition, it is necessary to increase the output voltage of the transmission inverter. However, even when the distance between the coils is close to 0, the power transmission inverter can operate stably when the inductivity of the input impedance seen from the power transmission inverter hardly changes compared to when the distance between the coils is somewhat large. In addition, there is no need to increase the output voltage of the transmission inverter.

In this way, the present disclosure relates to a non-contact power transmission technology in which the inter-coil distance is variable, and even when the inter-coil distance is close to 0, at the power transmission frequency satisfies the resonance condition, and the power transmission efficiency can be increased.

It is a figure which shows the structure of the conventional non-contact electric power transmission system. 1 is a diagram showing a configuration of a first contactless power transmission system of the present disclosure; FIG. FIG. 3 is a diagram showing the configuration of a second contactless power transmission system of the present disclosure; FIG. 10 is a diagram showing the configuration of a third contactless power transmission system of the present disclosure; FIG. 3 is a diagram showing a configuration of a first contactless power transmission coil of the present disclosure; FIG. 5 is a diagram showing the configuration of a second contactless power transmission coil of the present disclosure; FIG. 4 is a diagram showing the configuration of a third contactless power transmission coil of the present disclosure; 1 is a diagram showing a configuration of a power transmission inverter of the present disclosure; FIG. FIG. 5 is a diagram showing through current and loss of a power transmission inverter of a comparative example; FIG. 4 is a diagram showing shoot-through current and loss of the power transmission inverter of the present disclosure;

Embodiments of the present disclosure will be described with reference to the accompanying drawings. The embodiments described below are examples of implementing the present disclosure, and the present disclosure is not limited to the following embodiments.

FIG. 1 shows the configuration of a conventional contactless power transmission system. A conventional contactless power transmission system S includes a contactless power transmission coil 1T, a power transmission inverter 2, and a capacitor 3 on the power transmission side, and a contactless power transmission coil 1R, a capacitor 4, and a load 5 on the power receiving side. A contactless power transmission coil 1T is composed of a winding 11T and a core 12T. The contactless power transmission coil 1R is composed of a winding 11R and a core 12R.

The contactless power transmission coil 1T (inductance L _T ) and capacitor 3 (capacitance C _T ) are connected in series. The contactless power transmission coil 1R (inductance L _R ) and capacitor 4 (capacitance C _R ) are connected in series. Such a connection method is called an SS (Series-Series) method. By adopting the SS method, the power transmission efficiency is increased when the resonance conditions on the power transmitting side and the power receiving side at the power transmission frequency f are satisfied.

Cores 12T and 12R are rod-shaped cores. The extension axes of the contactless power transmission coils 1T and 1R are parallel to each other, and the distance between them is variable. For example, the non-contact power transmission coil 1T is arranged at a mounting portion of a door that slides in a straight line. Then, the non-contact power transmission coil 1R supplies power to an electric lock of a door that slides in a straight line or to a lighting fixture.

In a state where the distance between the coils is separated to some extent, the inductances L _T and L _R of the contactless power transmission coils 1T and 1R and the capacitances C of the capacitors 3 and 4 are set so as to satisfy the resonance condition at the power transmission frequency f and increase the power transmission efficiency. Design _T and _CR .

When the distance between the coils approaches approximately 0, the interlinkage magnetic flux from the cores 12T/12R to the contactless power transmission coils 1R/1T becomes larger than when the distance between the coils is somewhat large, and the contactless power is reduced. The inductance L _R /L _T of the transmission coils 1R/1T increases. Therefore, when the inter-coil distance is close to 0, unlike the case where the inter-coil distance is a certain distance, the resonance condition on the power transmitting side and the power receiving side at the power transmission frequency f cannot be satisfied, and the power transmission efficiency cannot be increased.

As shown in FIGS. 8 to 10, it is desirable that the input impedance _ZIN seen by the transmission inverter 2 is slightly inductive. Here, in a state where the inter-coil distance approaches approximately 0, compared to a state where the inter-coil distance is somewhat distant, when the inductivity of the input impedance Z _IN seen from the power transmission inverter 2 becomes too large, the power transmission inverter 2 In addition, it is necessary to increase the output voltage of the power transmission inverter 2 .

FIG. 2 shows the configuration of the first contactless power transmission system of the present disclosure. In the first contactless power transmission system S of the present disclosure, in addition to the conventional contactless power transmission system S, the contactless power transmission coil 1T includes a nonmagnetic conductor 13T such as Cu, Al, Ag, and Au, The non-contact power transmission coil 1R includes a non-magnetic conductor 13R such as Cu, Al, Ag and Au.

The non-magnetic conductor 13T is arranged in the space facing the non-contact power transmission coil 1R and near the core 12T. The non-magnetic conductor 13R is arranged in a space facing the contactless power transmission coil 1T and near the core 12R.

Part of the magnetic flux linkage from the cores 12T/12R to the contactless power transmission coils 1R/1T is canceled by eddy current generation in the non-magnetic conductors 13T/13R. Therefore, even when the distance between the coils approaches approximately 0, the interlinkage magnetic flux from the cores 12T/12R to the contactless power transmission coils 1R/1T hardly changes compared to when the distance between the coils is somewhat large. , the inductances L _R /L _T of the contactless power transmission coils 1R/1T also change little. Then, even when the inter-coil distance is close to 0, the power transmission efficiency can be increased by satisfying the resonance conditions on the power transmission side and the power reception side at the power transmission frequency f, as in the case where the inter-coil distance is somewhat distant. .

As shown in FIGS. 8 to 10, it is desirable that the input impedance _ZIN seen by the transmission inverter 2 is slightly inductive. Here, when the inductivity of the input impedance Z _IN seen from the power transmission inverter 2 changes little compared to the state where the distance between the coils is somewhat distant even when the distance between the coils approaches approximately 0, the power transmission inverter 2 can operate stably, and there is no need to increase the output voltage of the power transmission inverter 2 .

The sizes of the non-magnetic conductors 13T/13R are desirably designed according to the following criteria: (1) part of the interlinking magnetic flux from the cores 12T/12R to the contactless power transmission coils 1R/1T is eddy; (2) All of the magnetic flux linkage from the cores 12T/12R to the contactless power transmission coils 1R/1T is not canceled by the eddy current generation.

For example, the size of the non-magnetic conductors 13T/13R in the direction parallel to the extension axis of the contactless power transmission coils 1T/1R is greater than or equal to the winding length of the windings 11T/11R and less than or equal to the extension length of the cores 12T/12R. is desirable. The size of the non-magnetic conductors 13T/13R in the direction perpendicular to the extension axis of the non-contact power transmission coils 1T/1R must be equal to or less than the winding diameter of the windings 11T/11R and equal to or less than the diameter of the cores 12T/12R. is desirable.

FIG. 3 shows the configuration of the second contactless power transmission system of the present disclosure. In the second contactless power transmission system S of the present disclosure, in addition to the conventional contactless power transmission system S, the contactless power transmission coil 1R includes a nonmagnetic conductor 13R such as Cu, Al, Ag, and Au. , the contactless power transmission coil 1T does not include a non-magnetic conductor 13T such as Cu, Al, Ag and Au.

The non-magnetic conductor 13R is arranged in a space facing the contactless power transmission coil 1T and near the core 12R. The non-magnetic conductor 13T is not arranged as described above.

A part of the interlinking magnetic flux from the core 12R to the non-contact power transmission coil 1T is canceled by eddy current generation in the non-magnetic conductor 13R. Therefore, even when the inter-coil distance is close to 0, the interlinking magnetic flux from the core 12R to the non-contact power transmission coil 1T hardly changes compared to the case where the inter-coil distance is a certain distance. The inductance _LT of the transmission coil 1T also hardly changes. Then, even when the inter-coil distance is close to 0, the power transmission efficiency can be increased by satisfying the resonance condition on the power transmission side at the power transmission frequency f, as in the case where the inter-coil distance is a certain distance away.

Even if the inductance L _R of the non-contact power transmission coil 1R changes slightly, the resonance Q value on the power receiving side is small due to the presence of the load 5 (resistance value R). almost filled. Moreover, since the non-magnetic conductor 13T is not arranged on the power transmission side, eddy current loss on the power transmission side is reduced, and power transmission efficiency can be improved.

As shown in FIGS. 8 to 10, it is desirable that the input impedance _ZIN seen by the transmission inverter 2 is slightly inductive. Here, when the inductivity of the input impedance Z _IN seen from the power transmission inverter 2 changes little compared to the state where the distance between the coils is somewhat distant even when the distance between the coils approaches approximately 0, the power transmission inverter 2 can operate stably, and there is no need to increase the output voltage of the power transmission inverter 2 .

The size of the non-magnetic conductor 13R is desirably designed according to the following criteria: (1) part of the magnetic flux linkage from the core 12R to the contactless power transmission coil 1T is canceled by eddy current generation; (2) All of the interlinkage magnetic flux from the core 12R to the non-contact power transmission coil 1T is not canceled by eddy current generation.

For example, it is desirable that the size of the non-magnetic conductor 13R in the direction parallel to the extension axis of the contactless power transmission coil 1R is greater than or equal to the winding length of the winding 11R and less than or equal to the extension length of the core 12R. The size of the non-magnetic conductor 13R in the direction perpendicular to the extension axis of the contactless power transmission coil 1R is preferably equal to or less than the winding diameter of the winding 11R and equal to or less than the diameter of the core 12R.

FIG. 4 shows the configuration of the third contactless power transmission system of the present disclosure. In the third contactless power transmission system S of the present disclosure, in addition to the conventional contactless power transmission system S, the contactless power transmission coils 1T and/or 1R include nonmagnetic conductors such as Cu, Al, Ag, and Au. 13.

The non-magnetic conductor 13 is installed in the space where the non-contact power transmission coils 1T and 1R face each other and in the housing fixing the cores 12T and/or 12R.

Part of the magnetic flux linkage from the cores 12T/12R to the contactless power transmission coils 1R/1T is canceled by eddy current generation in the non-magnetic conductor 13 . Therefore, even when the distance between the coils approaches approximately 0, the interlinkage magnetic flux from the cores 12T/12R to the contactless power transmission coils 1R/1T hardly changes compared to when the distance between the coils is somewhat large. , the inductances L _R /L _T of the contactless power transmission coils 1R/1T also change little. Then, even when the inter-coil distance is close to 0, the power transmission efficiency can be increased by satisfying the resonance conditions on the power transmission side and the power reception side at the power transmission frequency f, as in the case where the inter-coil distance is somewhat distant. .

In addition, since the non-magnetic conductor 13 is arranged in the opposing space on the power transmission/reception side, eddy current loss on the power transmission side and the power reception side is reduced, and power transmission efficiency can be improved.

As shown in FIGS. 8 to 10, it is desirable that the input impedance _ZIN seen by the transmission inverter 2 is slightly inductive. Here, when the inductivity of the input impedance Z _IN seen from the power transmission inverter 2 changes little compared to the state where the distance between the coils is somewhat distant even when the distance between the coils approaches approximately 0, the power transmission inverter 2 can operate stably, and there is no need to increase the output voltage of the power transmission inverter 2 .

The size of the nonmagnetic conductor 13 is desirably designed according to the following criteria: (1) part of the interlinking magnetic flux from the cores 12T/12R to the contactless power transmission coils 1R/1T generates eddy current; (2) Not all of the magnetic flux linkage from the cores 12T/12R to the contactless power transmission coils 1R/1T is canceled by eddy current generation.

For example, the size of the non-magnetic conductor 13 in the direction parallel to the extension axes of the contactless power transmission coils 1T and 1R is greater than or equal to the winding length of the windings 11T and 11R and less than or equal to the extension length of the cores 12T and 12R. desirable. The size of the non-magnetic conductor 13 in the direction perpendicular to the extension axes of the non-contact power transmission coils 1T and 1R is preferably equal to or less than the winding diameters of the windings 11T and 11R and is equal to or less than the diameters of the cores 12T and 12R. .

FIG. 5 shows the configuration of the first contactless power transmission coil of the present disclosure. The first contactless power transmission coil 1 of the present disclosure is composed of a winding 11, a core 12, a non-magnetic conductor 13 and a housing 14. The left column of FIG. 5 shows a plan view, and the right column of FIG. 5 shows a sectional view taken along the line AA.

Winding 11 is wound around core 12 . The non-magnetic conductor 13 is arranged directly above the core 12 around which the winding 11 is wound, and is insulated from the winding 11 . The housing 14 is a housing made of aluminum or the like, and has a recess in which the winding 11, the core 12 and the non-magnetic conductor 13 are embedded. Input and output wiring (not shown in FIG. 5) of the winding 11 are routed inside the housing 14 .

The size of the non-magnetic conductor 13 in the direction parallel to the extension axis of the contactless power transmission coil 1 is about the extension length of the core 12 . The size of the non-magnetic conductor 13 in the direction perpendicular to the extension axis of the contactless power transmission coil 1 is equal to or less than the winding diameter of the winding wire 11 and equal to or less than the diameter of the core 12 .

The first contactless power transmission coil 1 of the present disclosure can be applied in place of the contactless power transmission coils 1T and 1R shown in FIG. 2 or the contactless power transmission coil 1R shown in FIG.

FIG. 6 shows the configuration of the second contactless power transmission coil of the present disclosure. The second contactless power transmission coil 1 of the present disclosure is composed of a winding 11, a core 12, a non-magnetic conductor 13 and a housing 14. The left column of FIG. 6 shows a plan view, and the right column of FIG. 6 shows a cross-sectional view taken along the line BB.

The non-magnetic conductor 13 is arranged directly above the core 12 or patterned on a substrate (not shown in FIG. 6) made of resin or the like arranged directly above the core 12 . The winding 11 is wound around a core 12 on which a non-magnetic conductor 13 is arranged and is insulated from the non-magnetic conductor 13 . The housing 14 is a housing made of aluminum or the like, and has a recess in which the winding 11, the core 12 and the non-magnetic conductor 13 are embedded. Input and output wiring (not shown in FIG. 6) of the winding 11 are routed inside the housing 14 .

The size of the non-magnetic conductor 13 in the direction parallel to the extension axis of the contactless power transmission coil 1 is about the extension length of the core 12 . The size of the non-magnetic conductor 13 in the direction perpendicular to the extension axis of the contactless power transmission coil 1 is equal to or less than the winding diameter of the winding wire 11 and equal to or less than the diameter of the core 12 .

The second contactless power transmission coil 1 of the present disclosure can be applied as the contactless power transmission coils 1T and 1R shown in FIG. 2 or the contactless power transmission coil 1R shown in FIG.

FIG. 7 shows the configuration of the third contactless power transmission coil of the present disclosure. A third contactless power transmission coil 1 of the present disclosure is composed of a winding 11 , a core 12 , a nonmagnetic conductor 13 and a housing 14 . The left column of FIG. 7 shows a plan view, and the right column of FIG. 7 shows a cross-sectional view taken along line CC.

Winding 11 is wound around core 12 . The housing 14 is a housing made of aluminum or the like, and has a recess in which the windings 11 and the core 12 are embedded. The non-magnetic conductor 13 is arranged above the recess of the housing 14 , is spaced from the windings 11 and the core 12 , and is insulated from the windings 11 . Input and output wiring (not shown in FIG. 7) of the winding 11 are routed inside the housing 14 .

The size of the non-magnetic conductor 13 in the direction parallel to the extension axis of the contactless power transmission coil 1 is about the extension length of the core 12 . The size of the non-magnetic conductor 13 in the direction perpendicular to the extension axis of the contactless power transmission coil 1 is equal to or less than the winding diameter of the winding wire 11 and equal to or less than the diameter of the core 12 .

The third contactless power transmission coil 1 of the present disclosure can be applied as the contactless power transmission coil 1T and/or the contactless power transmission coil 1R shown in FIG.

In this embodiment, the cores 12T and 12R are rod-shaped cores, and the extension axes of the non-contact power transmission coils 1T and 1R are parallel to each other and the distance between them is variable. As a modification, the cores 12T and 12R may each be rod-shaped cores, and the ends of the rod-shaped cores of the non-contact power transmission coils 1T and 1R may face each other and the distance between them may be variable.

Also in the modified example, the size of the non-magnetic conductor 13 is desirably designed according to the following criteria: (1) part of the interlinking magnetic flux from the cores 12T/12R to the contactless power transmission coils 1R/1T is (2) All of the magnetic flux linkage from the cores 12T/12R to the non-contact power transmission coils 1R/1T is not canceled by the eddy current generation.

When the power transmission frequency f is on the order of MHz, heat generation in the nonmagnetic conductor 13 due to eddy current generation in the nonmagnetic conductor 13 is small. When the power transmission frequency f is on the order of kHz, heat is generated in the non-magnetic conductor 13 due to eddy current generation in the non-magnetic conductor 13. A cooling mechanism is sufficient.

FIG. 8 shows the configuration of the power transmission inverter of the present disclosure. The power transmission inverter 2 is a full bridge circuit and is composed of a high side transistor 2AH, a low side transistor 2AL, a high side transistor 2BH and a low side transistor 2BL.

The voltage applied to the high-side transistor 2AH and the current flowing therethrough are _VAH and _IAH , respectively. Let V _AL and I _AL be the voltage applied to the low-side transistor 2AL and the current flowing therethrough, respectively. The voltage applied to the high-side transistor 2BH and the current flowing therethrough are V _BH and I _BH , respectively. The voltage applied to the low-side transistor 2BL and the current flowing therethrough are V _BL and I _BL , respectively. The voltage output from the power transmission inverter 2 and the current flowing therefrom are V _T and I _T , respectively.

FIG. 9 shows the through current and loss of the power transmission inverter of the comparative example. In the power transmission inverter 2 of the comparative example, the input impedance _ZIN seen by the power transmission inverter 2 is slightly more capacitive than purely resistive. That is, the phase of the current _IT leads the phase of the voltage _VT by a small amount.

Now, consider the case where the high side transistor 2AH (2BH) is switched from ON to OFF and the low side transistor 2AL (2BL) is switched from OFF to ON. At this time, a forward current I _AH (I _BH )<0 flows through the body diode of the high-side transistor 2AH (2BH). Then, a voltage V _AH (V _BH )>0 is applied to the high-side transistor 2AH (2BH). Then, a recovery current flows in the opposite direction through the body diode of the high-side transistor 2AH (2BH). Therefore, a through current having a magnitude indicated by a black circle flows from the high-side transistor 2AH (2BH) to the low-side transistor 2AL (2BL). Then, in the power transmission inverter 2, a loss of the magnitude indicated by the black circle occurs. It should be noted that when the high side transistor 2AH (2BH) is switched from off to on and the low side transistor 2AL (2BL) is switched from on to off, the above description is the same.

FIG. 10 shows the shoot-through current and loss of the transmission inverter of the present disclosure. In the transmission inverter 2 of the present disclosure, the input impedance Z _IN seen by the transmission inverter 2 is slightly more inductive than purely resistive. That is, the phase of the current _IT is slightly delayed from the phase of the voltage _VT .

Now, consider the case where the high side transistor 2AH (2BH) is switched from ON to OFF and the low side transistor 2AL (2BL) is switched from OFF to ON. At this time, the forward current I _AH (I _BH )<0 does not flow through the body diode of the high-side transistor 2AH (2BH). Therefore, the through current of the magnitude indicated by the black circle in FIG. 9 does not flow from the high side transistor 2AH (2BH) to the low side transistor 2AL (2BL). In addition, in the power transmission inverter 2, the loss of the magnitude indicated by the black circles in FIG. 9 does not occur. It should be noted that when the high side transistor 2AH (2BH) is switched from off to on and the low side transistor 2AL (2BL) is switched from on to off, the above description is the same.

Therefore, it is desirable that the input impedance Z _IN seen from the power transmission inverter 2 is slightly more inductive than pure resistance. Here, the phrase “it is slightly more inductive than purely resistive” means that the phase of the current _IT is adjusted to the voltage level to the extent that optimization of contactless power transmission efficiency and reduction of loss in the power transmission inverter 2 are compatible. It means to delay the phase of _VT (maximum phase difference is π/4 rad).

The non-contact power transmission coil, the non-contact power transmission device, and the non-contact power transmission system of the present disclosure can be applied to non-contact power transmission in which the distance between the coils is variable. It can be applied for the purpose of non-contact power transmission to a door lighting fixture.

S: Contactless power transmission system 1, 1T, 1R: Contactless power transmission coil 2: Power transmission inverter 2AH: High side transistor 2AL: Low side transistor 2BH: High side transistor 2BL: Low side transistors 3, 4: Capacitor 5: Load 11, 11T, 11R: windings 12, 12T, 12R: cores 13, 13T, 13R: non-magnetic conductor 14: housing

Claims (6)

A contactless power transmission device including contactless power transmission coils in which windings are wound around a rod-shaped core on both the power transmitting side and the power receiving side,
The extension axes of the contactless power transmission coils on the power transmission side and the power reception side are parallel to each other, and the distance between each other in the direction perpendicular to the extension axis is variable,
further comprising a non-magnetic conductor in a space where the contactless power transmission coils on the power transmission side and the power reception side face each other;
In a state in which the distance between the contactless power transmission coils on the power transmission side and the power receiving side is closer, compared to a state in which the distance between the contactless power transmission coils on the power transmission side and the power receiving side is greater. , part of the magnetic flux linkage between the contactless power transmission coils on the power transmission side and the power reception side is canceled by eddy current generation in the non-magnetic conductor;
Within the range where contactless power transmission is possible, the magnetic flux linkage between the contactless power transmission coils on the power transmission side and the power receiving side and the inductance of the contactless power transmission coils on the power transmission side and the power receiving side are: regardless of the distance between the contactless power transmission coils on the power transmission side and the power reception side,
Even when the distance between the contactless power transmission coils on the power transmission side and the power receiving side is the shortest, it is similar to the state where the distance between the contactless power transmission coils on the power transmission side and the power receiving side is longer. , satisfying the resonance condition at the power transmission frequency of the contactless power transmission coils on the power transmission side and the power reception side
A contactless power transmission device characterized by: The size of the non-magnetic conductor in the direction parallel to the extension axes of the contactless power transmission coils on the power transmission side and the power reception side is equal to or greater than the winding length of the windings on the power transmission side and the power reception side, and the power transmission 2. The contactless power transmission device according to claim 1, wherein the extension length is equal to or less than the extension length of the rod-shaped core on the side and the power receiving side. The contactless power transmission coils on the power transmitting side and the power receiving side have the non-magnetic conductor disposed in the vicinity of the rod-shaped cores of the contactless power transmission coils on the power transmitting side and the power receiving side,
The non-magnetic conductor is arranged so as to be in contact with the rod-shaped cores of the contactless power transmission coils on the power transmission side and the power reception side, or is in contact with the rod-shaped cores of the contactless power transmission coils on the power transmission side and the power reception side. patterned on a substrate arranged to
The windings of the power transmission side and the power reception side are wound around rod-shaped cores of the contactless power transmission coils of the power transmission side and the power reception side in which the nonmagnetic conductor is arranged, and are insulated from the nonmagnetic conductor. The contactless power transmission device according to claim 2, characterized by: The contactless power transmission coil only on the power receiving side excluding the power transmission side is arranged so that the non-magnetic conductor is in the vicinity of the rod-shaped core of the contactless power transmission coil only on the power receiving side excluding the power transmission side,
The non-magnetic conductor is arranged so as to be in contact with the rod-shaped core of the contactless power transmission coil only on the power receiving side excluding the power transmission side, or the contactless power transmission coil only on the power receiving side excluding the power transmission side. patterned on a substrate positioned in contact with the rod-shaped core;
The winding only on the power receiving side excluding the power transmission side is wound around a rod-shaped core of the contactless power transmission coil only on the power receiving side excluding the power transmission side in which the non-magnetic conductor is arranged, and the non-magnetic conductor and The contactless power transmission device according to claim 2, wherein the contactless power transmission device is insulated. The non-magnetic conductor fixes cores of the contactless power transmission coils of the power transmission side and/or the power reception side in a space where the contactless power transmission coils of the power transmission side and the power reception side face each other. 3. The contactless power transmission device according to claim 1, wherein the device is installed in a housing. A contactless power transmission device according to any one of claims 1 to 5, and a power transmission inverter,
an input impedance seen by the transmission inverter is inductive, and
A non-contact power transmission system, wherein non-contact power transmission between the non-contact power transmission coil on the power transmission side and the non-contact power transmission coil on the power reception side is performed by an SS (Series-Series) method.

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