JP2011010435A - Contactless power supply system and contactless power supply unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain high efficiency of transmission as much as possible and suppress effect due to a change in field to its outside as much as possible, in contactless power supply.SOLUTION: This contactless power supply unit, which contactlessly supplies power from a power supply to the destination of power supply, includes a receiving coil or a transmitting coil, a first housing which is a housing arranged opposite to a coil being the counterpart of a coil in contactless power supply system and has a surface area sufficient to cover a power supply face that the coil forms and is made of a magnetic material, and a second housing which is a housing arranged opposite to the coil across the first housing and has a surface area larger than that of the first housing in a direction along the power supply face of the coil and is made of a conductive material.

Description

  The present invention relates to an apparatus capable of supplying power in a contactless manner to a power supply destination from a power source.

  In the field of land transportation, research and development of automobiles that run on electric power has been actively conducted due to concerns about air pollution and depletion of fossil fuels. As an automobile that travels using electric power, for example, there is a type that travels using electric power stored in a secondary battery. As a technique for charging a secondary battery mounted on an automobile, there is a technique for charging by receiving power from a power feeding unit provided on a traveling path in a non-contact manner (for example, see Patent Document 1).

  Further, as a technique for supplying electric power in a non-contact manner, there has been a technique using electromagnetic induction. However, in this electromagnetic induction system, the power transmission efficiency decreases significantly as the distance between the power source and the power supply destination increases. Therefore, as an alternative technique, there is one that sends power with high power transmission efficiency to power supply destinations that are separated using magnetic field resonance (see, for example, Patent Document 2).

JP 2008-120357 A JP 2008-301918 A

  2. Description of the Related Art Conventionally, as a technique for supplying power from a power source to a power supply destination in a contactless manner, there is a wireless power transmission technique using electromagnetic induction between coils. However, the electromagnetic induction power transmission method has the advantage that there is no need to expose the contacts on the power transmission side and the power reception side, but the power transmission efficiency drops extremely as the coil interval becomes longer. In most cases, it was used in such a state. In addition to such an electromagnetic induction method, conventionally, there is a wireless power transmission technology using magnetic resonance (also referred to as magnetic resonance, magnetic resonance, or magnetic resonance) between coils having the same resonance frequency. In the power transmission method using magnetic field resonance, the coil interval can be made longer than in the electromagnetic induction method.

  In these non-contact power supply technologies, due to the influence of the magnetic field generated by the power transmission coil, eddy currents are generated in the surrounding conductive members and power is lost, resulting in power transmission efficiency. Will fall. In addition, in these technologies, a magnetic field is generated between the power transmission coil on the power source side and the power receiving coil on the power supply side. Therefore, the strength of the magnetic field is limited to the devices and human bodies existing around the space where power is supplied. There is also a possibility of adversely affecting the above. In particular, the effect of this magnetic field becomes more prominent as the power to be transmitted increases.

  In view of the above-described problems, the present invention aims to maintain the power transmission efficiency as high as possible when supplying electric power in a non-contact manner, and to suppress as much as possible the influence due to the change in the magnetic field to the outside. And

In order to solve the above-described problems, the present invention forms a housing for a power transmission coil or a power reception coil for supplying non-contact power by a magnetic member made of a magnetic material and a conductive member made of a conductive member. Originally devised the arrangement of members. By adopting this unique housing configuration of the present invention, it is possible to effectively suppress the generation of eddy currents during power supply and to effectively suppress the influence of a magnetic field leaking to the outside.

  Specifically, the present invention is a contactless power supply unit that supplies power from a power source to a power supply destination in a contactless manner, and receives power at the power supply destination side in the contactless power supply. A power receiving coil to be formed, or a power feeding coil formed of any one of the power transmitting coils that transmit power on the power source side in the non-contact power supply, and a counterpart of the power feeding coil in the non-contact power supply A housing disposed on the opposite side of the coil, having a surface area that covers at least a power supply surface formed by the power supply coil, and a first housing made of a magnetic material, and sandwiching the first housing And a housing disposed on the opposite side of the power supply coil, and having a surface area larger than the first housing in a direction along the power supply surface of the power supply coil, and And a second housing formed with conductive material.

  The non-contact type power supply unit includes a power transmission coil or a power reception coil as a power supply coil, and is formed when power is supplied from a power source to a power supply destination in a non-contact type. It corresponds to any one of the power supply units. In other words, power is transmitted from the non-contact power supply unit on the power transmission side, and power is supplied from the power source to the power supply destination by the non-contact power supply unit on the power receiving side receiving the power. Become. Note that examples of the non-contact power supply method include a method using electromagnetic induction, a method using magnetic field resonance, and the like.

  The non-contact power supply unit includes at least a first housing and a second housing as a housing for the power feeding coil. The first housing has a surface area that covers at least the power supply surface of the power feeding coil. The power supply surface is a surface formed by a coil that contributes to the power supply when power is supplied between the power transmission coil and the power reception coil. Therefore, the first housing formed of this magnetic material is arranged at a position where most of the magnetic flux passes when power is supplied. On the other hand, the second housing formed of a conductive material is disposed on the back side (the side opposite to the power feeding coil) of the first housing and further has a larger surface area than the first housing. In other words, when these housings are viewed from the power supply coil, the second housing disposed on the back side is partly or entirely outside the first housing disposed on the front side (the power transmission coil). The portion of the second housing that is in the extended state (hereinafter referred to as the extending portion of the second housing) is referred to as the “extending portion of the second housing”. ).

  By adopting such a housing configuration, the first housing made of a magnetic material and the second housing made of a conductive material overlap each other in the vicinity of the power supply surface of the power supply coil (the two housings do not necessarily need to contact each other). ) And since the 2nd housing exists in the back | inner side rather than the 1st housing, the leakage of the magnetic flux to the back | inner side from this 2nd housing can be suppressed effectively. However, the vicinity of the power supply surface is a place where the magnetic flux density becomes high when power is supplied, and the generation of eddy current due to the magnetic flux passing through the second housing is a factor that reduces the transmission efficiency during power supply. A first housing is disposed on the front side of the two housings. Thus, the presence of the first housing made of a magnetic material can suppress the amount of magnetic flux passing through the second housing, that is, an efficient magnetic field formation for power supply is performed.

Furthermore, due to the difference in size between the first housing and the second housing described above, an extended portion of the second housing exists at a place that is laterally removed from the power supply surface. Since the second housing is formed of a conductive material, magnetic field leakage in a direction along the power supply surface of the power feeding coil (hereinafter referred to as “predetermined external direction”) is effectively suppressed. That is, the magnetic flux generated toward the predetermined external direction of the magnetic flux generated at the time of power supply passes through the extended portion of the second housing and generates eddy current there, thereby reducing the strength of the magnetic field leaking to the outside. Is possible.

  In this way, the non-contact power supply unit maintains the transmission efficiency at the time of power supply as high as possible by devising the arrangement of the first housing made of magnetic material and the second housing made of conductive material, It is possible to suppress as much as possible the influence of an external magnetic field change.

  In the non-contact power supply unit, the outer peripheral end of the first housing may extend outward from the outer peripheral end of the power feeding coil on the entire circumference. With this configuration, as much magnetic flux as possible is guided to the first housing by the magnetic member in a place where the magnetic flux density is relatively high. Therefore, it is possible to form a magnetic field for more efficient power supply. Note that the dimensions (size, thickness, etc.) of the first housing are preferably selected so as not to cause saturation of the expected passing magnetic flux.

  In the non-contact power supply unit described above, the outer peripheral end of the second housing may extend outward from the outer peripheral end of the first housing on the entire periphery. With this configuration, the extended portion of the second housing can be appropriately secured, and thus the strength of the magnetic field leaking to the outside can be more effectively reduced.

  In addition, as an example of a specific aspect of the non-contact power supply unit up to the above, the unit is a unit that supplies power from the power source installed on the road surface to the battery of the mobile body as the power supply destination. There may be. Examples of the moving body include vehicles such as automobiles and walking robots. In order not to impair the mobility and mobility of such a moving body, a method of supplying electric power in a non-contact manner is useful, and by adopting the non-contact electric power supply unit according to the present invention, efficiency is improved. Thus, it is possible to achieve both a stable power supply and suppression of magnetic field leakage to the outside.

  And in the said non-contact-type electric power supply unit which bears the electric power supply to a moving body, said 2nd housing is a member installed in the said road surface, and is in a shared state with the electroconductive member formed with the electroconductive material. It may be configured, or may be configured in a shared state with a conductive member that is a main body member of the moving body and formed of a conductive material. That is, a practical non-contact power supply unit can be formed more compactly by configuring the second housing in a shared state with a member installed on the road surface or a main body member of the moving body.

  In the non-contact power supply unit described above, the area of the extended portion of the second housing existing between the outer peripheral end of the second housing and the outer peripheral end of the first housing is determined when power is supplied. It is preferable that the magnetic field intensity detected at a predetermined position on the side of the movable body is designed to be not more than a predetermined reference intensity. As described above, the extended portion of the second housing can be said to be a configuration that suppresses leakage of the magnetic field to the outside, so that a predetermined reference strength that allows an external influence at the predetermined position is achieved. What is necessary is just to design the said extension part.

It is also possible to grasp the non-contact power supply unit according to the present invention from another aspect. That is, the present invention is a contactless power supply unit that supplies power from a power source to a power supply destination in a contactless manner, and receives power at the power supply destination side in the contactless power supply. A coil for power feeding formed by any one of a coil or a power transmission coil that transmits power on the power source side in the non-contact power supply, and a coil on the other side of the power feeding coil in the non-contact power supply Is a housing disposed on the opposite side, and a magnetic member layer formed of a magnetic material and a conductive member layer formed of a conductive material are formed in order from the power supply coil side, and the power supply coil is formed. A central housing that is disposed and formed so as to cover the power supply surface, and a conductive material that is disposed on the side of the central housing in a direction along the power supply surface of the power supply coil. In comprising a lateral housing formed, the.

  In the non-contact type power supply unit, similarly to the unit already described, power is transmitted from the non-contact type power supply unit on the power transmission side, and the power is received by the non-contact type power supply unit on the power receiving side. Power supply from the power source to the power supply destination is realized. Here, the central housing disposed opposite to the power supply surface of the power supply coil is formed of a magnetic member layer and a conductive member layer in order from the power supply coil. Therefore, similarly to the non-contact power supply unit described above, it is possible to efficiently form a magnetic field by the magnetic member layer and suppress magnetic field leakage by the conductive member. In addition, a side housing formed of a conductive material is disposed on the side of the central housing. As a result, the magnetic flux generated on the power supply surface during power supply and directed toward the predetermined external direction passes through the side housing to generate an eddy current there. As a result, the magnetic field leaked to the outside during power supply is increased. It becomes possible to weaken.

  As described above, the non-contact power supply unit captured from a new aspect also improves the power transmission efficiency during power supply by devising the arrangement of the central housing and the side housing with magnetic material and / or conductive material. While maintaining as high as possible, it becomes possible to suppress as much as possible the influence of external magnetic field changes. In consideration of leakage of the magnetic field to the outside, it is preferable to arrange the side housing with no gap with respect to the central housing. However, an appropriate gap may be provided between the two housings as long as leakage of the magnetic field is allowed. Absent. In addition, the relative positions of the central housing and the side housing in the thickness direction can be adjusted as appropriate as long as the side housing is disposed on the side of the central housing and magnetic field leakage is allowed.

  Here, in the non-contact power supply unit, the conductive member layer of the central housing and the side housing may be formed of the same conductive member made of a conductive material. That is, the configuration of the non-contact power supply unit can be simplified by forming the configuration formed of the conductive material common to the central housing and the side housing with the same conductive member. .

  Moreover, also in the non-contact-type power supply unit provided with a center housing and a side housing, as an example of the specific aspect, the said non-contact-type power supply unit is used as the said power supply destination from the said power supply installed in the road surface. A unit for supplying electric power to the battery of the mobile body.

  The non-contact type power supply unit up to the above forms either the power transmission side or the power reception side in the power supply, but the present invention is a non-contact type power supply unit on the power transmission side and a non-contact type power supply unit on the power reception side. You may grasp as a non-contact-type electric power supply apparatus comprised by both units. That is, the present invention is a non-contact power supply apparatus that supplies power from a power source to a power supply destination in a non-contact manner, which includes at least two non-contact power supply units described above. The at least one non-contact type power supply unit of the at least two non-contact type power supply units is a unit including the power feeding coil as a power receiving coil that receives power at the power supply destination side. Of the two non-contact power supply units, the remaining non-contact power supply unit is a unit including the power feeding coil as a power transmission coil that performs power transmission on the power source side. With this non-contact power supply device, non-contact power supply can be realized between the power source and the power supply destination. Note that the housing may be configured in an appropriate shape such as a plate shape, or may be configured on one surface of a housing that houses the power feeding coil.

  When supplying electric power in a non-contact manner, the power transmission efficiency is maintained as high as possible, and the influence of external magnetic field changes is suppressed as much as possible.

It is a figure which shows the example of installation to the vehicle and the road surface of the apparatus which supplies electric power by a non-contact type based on this invention. It is a figure which shows schematic structure of the electric power supply apparatus shown in FIG. It is a figure which shows schematically the structure of the power transmission coil and power receiving coil which are used in the electric power supply apparatus shown in FIG. It is sectional drawing which shows the structure of the power supply unit of the power transmission side or power receiving side which forms the power supply apparatus shown in FIG. It is a correlation of the power supply unit of the power transmission side and the power receiving side which forms the power supply apparatus shown in FIG. It is a 1st figure showing the mode of the magnetic field on the XZ plane formed between the power transmission coil and a receiving coil at the time of assuming the conventional non-contact-type electric power supply apparatus. It is a 2nd figure showing the mode of the magnetic field on the XZ plane formed between the power transmission coil and a receiving coil at the time of assuming the conventional non-contact-type electric power supply apparatus. 6A and 6B are graphs comparing the state of the magnetic field shown in FIGS. 6A and 6B from the viewpoint of the distance on the X axis and the magnetic field strength. It is a figure showing the mode of the magnetic field on the XZ plane formed between a power transmission coil and a receiving coil in the non-contact-type electric power supply apparatus which concerns on this invention. FIG. 9 is a graph comparing the state of the magnetic field shown in FIGS. 6B and 8 from the viewpoint of the distance on the X axis and the magnetic field strength. It is a graph which shows distribution of the magnetic flux density on the line L1 in FIG. In the non-contact-type electric power supply apparatus which concerns on this invention, it is a graph which shows the current density of the eddy current which arises in conductor plate shape. It is a figure which shows roughly the other structure of the power transmission coil and power receiving coil which are used in the electric power supply apparatus which concerns on this invention. It is a figure which shows the other structure of the non-contact-type electric power supply apparatus which concerns on this invention.

  Embodiments of a non-contact power supply apparatus according to the present invention will be described below with reference to the drawings. The power supply device 1 according to the present embodiment is a device that supplies power from a power source installed on the road surface side to a battery mounted on a vehicle as a moving body. As shown in FIG. The power receiving unit 20 is provided, and non-contact power supply is performed between the two units. The power transmission unit 10 is installed on the road surface side where the vehicle stops, and the power receiving unit 20 is installed on the vehicle side. However, the power supply device according to the present invention is not limited to the vehicle application, and can be applied to various devices using electric power, such as home appliances, information devices, and toys.

<Configuration of power supply device 1>
FIG. 1 is a diagram illustrating a configuration of a power supply device 1 according to the present embodiment. As described above, the power supply device 1 is roughly provided with two units, that is, a power transmission unit 10 and a power reception unit 20. Among these, the power transmission unit 10 is provided on the road surface side where the vehicle stops (for example, a parking space), and includes a power transmission controller 17, a converter 13, a power transmission amplifier 14, a power transmission coil 15, a resonance control unit 16, an oscillation circuit 18, A directional coupler 19, a traveling wave power meter 19 a, a reflected wave power meter 19 b, a load matching unit 19 c, and the data transmission / reception unit 12 are provided. Here, the power transmission coil 15 is connected to the power reception coil 25 of the power reception unit 20 provided on the bottom surface of the vehicle at a position where the alignment is easy when the vehicle stops, such as a predetermined position based on the parking stop of the parking space. It is preferable to be provided so as to face each other.

  The power transmission controller 17 is connected to a storage device, and a predetermined function necessary for power supply is exhibited by executing a control program there. For example, the power transmission controller 17 sets the oscillation circuit 18, the resonance according to the preset power transmission settings, the data transmission / reception unit 12 data transmission / reception result with the power reception unit 20, and the transmission power monitor result obtained from the power transmission amplifier 14. Control unit 16 and converter 13 are controlled. The data transmission / reception unit 12 is a communication interface for wireless communication connected to an antenna. Further, the converter 13 converts AC or DC power supplied from the power source into DC current and sends it to the power transmission amplifier 14. The output voltage from the converter 13 is controlled by the power transmission controller 17. Further, the power transmission amplifier 14 inputs the power transmitted from the converter 13 to the power transmission coil 15 at the frequency given from the oscillation circuit 18. Here, the frequency given by the oscillation circuit 18 is controlled by the power transmission controller 17.

  The resonance control unit 16 matches the resonance frequency of the power transmission unit 10 with the oscillation frequency of the oscillation circuit 18 by a method such as controlling the capacitance of the capacitor (capacitor) provided in the power transmission coil 15 in accordance with an instruction from the power transmission controller 17. Control to do. Further, the oscillation circuit 18 controls the frequency oscillated to the power transmission coil 15 to a predetermined value in accordance with an instruction from the power transmission controller 17.

  The directional coupler 19 takes out the traveling wave and the reflected wave of the power input from the power transmission amplifier 14 to the power transmission coil 15. The traveling wave power measuring device 19a and the reflected wave power measuring device 19b measure the traveling wave power and the reflected wave power extracted by the directional coupler 19, and the measurement results are used as the transmission power monitor value and the reflected power. The monitor value is notified to the power transmission controller 17. The load matching unit 19c performs matching between the power transmission amplifier 14 and the load.

  The power receiving unit 20 is provided in a vehicle and includes a power receiving controller 27, a power receiving coil 25, a resonance control unit 26, a rectifier circuit 28, a DC / DC converter 29, and a data transmission / reception unit 22. Similar to the resonance control unit 16, the resonance control unit 26 controls the resonance frequency of the power reception unit 20 to coincide with the oscillation frequency of the oscillation circuit 18 in accordance with an instruction from the power reception controller 27. As a result, the resonance frequency of the power transmission unit 10 and the resonance frequency of the power reception unit 20 are controlled to coincide with each other, and wireless power transmission by magnetic field resonance is possible. Here, the power receiving coil 25 is preferably provided at a position on the bottom surface of the vehicle facing the power transmission unit 10 installed on the ground. The power receiving unit 20 is connected to the in-vehicle battery 33 via the in-vehicle charge / discharge control device 31. The charge / discharge control device 31 discharges electric power for driving the vehicle from the in-vehicle battery 33 in response to the accelerator operation, and when the brake is operated, the electric power generated by the motor 32 is supplied to the in-vehicle battery 33. Controlled to be charged.

  The power receiving controller 27 is connected to a storage device, and a predetermined function necessary for power supply is exhibited by executing a control program there. For example, the power receiving controller 27 is configured according to the resonance power control unit 26 according to the preset power receiving settings, the data transmission / reception result of the data transmission / reception unit 22 with the power transmission unit 10, and the received power monitoring result obtained from the rectifier circuit 28. The rectifier circuit 28 and the DC / DC converter 29 are controlled. The data transmission / reception unit 22 is a communication interface for wireless communication connected to an antenna. Further, a current flows through the power receiving coil 25 due to magnetic field resonance with the power transmitting coil 15. Here, the power reception controller 27 controls the resonance control unit 26 so that the resonance frequency of the power reception coil 25 matches that of the power transmission unit 10 in order to generate magnetic field resonance with the power transmission coil 15.

The rectifier circuit 28 (AC / DC converter) and the DC / DC converter 29 can control the apparent load resistance on the power reception side by changing the voltage on the power transmission side by keeping the electric power taken out on the charge / discharge control side constant. .

  FIG. 3 is a diagram illustrating a configuration of the power transmission coil 15 and the power reception coil 25 used in the power supply device 1 illustrated in FIG. 2. The power transmission coil 15 includes a first power transmission coil 15a and a second power transmission coil 15b, and the power reception coil 25 includes a first power reception coil 25a and a second power reception coil 25b, thereby supplying power to each power supply unit by two coils. The entire device 1 forms a four-coil configuration. In this embodiment, the first power transmission coil 15a is a two-turn coil having a diameter of 170 mm, the second power transmission coil 15b and the first power-receiving coil 25a are coils having a diameter of 300 mm and a tenth turn, The power receiving coil 25b is a coil having a diameter of 157 mm and one turn.

  Here, the first power transmission coil 15 a is a coil to which power is directly supplied from the power transmission amplifier 14. When a current flows through the first power transmission coil 15a by the power transmission amplifier 14, electromagnetic induction occurs between the first power transmission coil 15a and the second power transmission coil 15b, and a current flows through the second power transmission coil 15b. Then, when a current flows through the second power transmission coil 15b, magnetic field resonance occurs between the second power transmission coil 15b and the first power reception coil 25a that have the same resonance frequency, and a current flows through the first power reception coil 25a. Furthermore, when a current flows through the first power receiving coil 25a, electromagnetic induction occurs between the first power receiving coil 25a and the second power receiving coil 25b, and a current flows through the second power receiving coil 25b. By utilizing the principle of magnetic field resonance in this way, power supply from the power transmission unit 10 to the power reception unit is performed in a non-contact manner. In the example shown in FIG. 3, a coil (current transmission coil 15 a and second power reception coil 25 b in this case) directly connected to a coil through which a current flows directly from the power transmission amplifier 14 and a load resistance on the power reception side, The coils used for power transmission by magnetic field resonance (here, the second power transmission coil 15b and the first power reception coil 25a) are not physically connected, but are connected by electromagnetic induction, so that the load resistance of each unit, etc. An influence of the configuration on the resonance frequency of the coil used for magnetic field resonance is suppressed.

  In this way, the non-contact power supply performed between the power transmission coil 15 in the power transmission unit 10 and the power reception coil 25 in the power reception unit 20 is performed through the power supply surface formed by each of the power transmission coil 15 and the power reception coil 25. It can be said that it is done. That is, the power supply surface is a surface formed by each coil that enables non-contact power supply, and in this embodiment, the surfaces of the power transmission coil 15 and the power reception coil 25 with a diameter of 300 mm are power supply surfaces.

  Next, the structure of the housing of the power transmission coil 15 and the power reception coil 25 in the power transmission unit 10 and the power reception unit 20 will be described with reference to FIGS. 4 and 5. Since the housing configurations of both units are substantially the same, in FIG. 4, the housing configuration of the power transmission unit 10 is shown in a sectional view on behalf of both units, and for the power receiving unit, refer to each configuration. Numbers are shown in parentheses. Further, FIG. 5 illustrates a facing state when power supply using the magnetic field resonance is performed from the power transmission unit 10 to the power reception unit 20. In this facing state, the distance (pitch) between the coils of both units is assumed to be 150 mm. The number of coils in each unit is two as shown in FIG. 3, but the description of the configuration is simplified in FIGS.

In the power transmission unit 10, to support the power transmission coil 15, below the power transmission coil 15, that is, at a position opposite to the opposite power reception coil 25 and to be concentric with the power transmission coil 15. A magnetic plate 11a having an outer diameter of φ400 mm made of a magnetic material (in this embodiment, a ferrite material is used) is provided as a first housing. Since the diameter of the power transmission coil 15 is φ300 mm as described above, the magnetic plate 11 a covers the power supply surface of the power transmission coil 15, and the magnetic plate 11 a is disposed on the entire circumference of the outer peripheral end of the power transmission coil 15. It is in the state extended in the direction (the left-right direction in FIG. 5) which goes to the outer side. Further, a conductive material is provided below the magnetic plate 11a, that is, at a position opposite to the power transmission coil 15 across the magnetic plate 11a as shown in FIG. (In this embodiment, aluminum is used. A conductive plate 11b having a diameter φ of 1000 mm is provided as the second housing. The conductive plate may be a non-magnetic material or a magnetic material.) Since the diameter of the magnetic plate 11a is φ400 mm as described above, the conductor plate 11b covers the surface of the magnetic plate 11a, and the conductor plate 11b is connected to the power supply device 1 at the entire outer periphery of the magnetic plate 11a. It is in a state of extending in the direction toward the outside (the left-right direction in FIG. 5).

  The power receiving unit 20 also has a housing configuration similar to that of the power transmitting unit 10. Although not shown in FIG. 5, the power transmission coil 15 and the power reception coil 25 are covered with resin covers 11c and 21c formed of polypropylene, ABS resin, or the like, and are protected from external impacts or the like. It becomes the composition which is done.

  As described above, in the power transmission unit 10 and the power reception unit 20 having the above-described housing configuration, the magnetic plates 11a (21a) and the conductor plates 11b (21b) are arranged in this order starting from the power transmission / reception coils arranged opposite to each other. In addition, the outer diameters of the power transmission / reception coil, the magnetic plate, and the conductor plate are formed larger in this order. In this way, in the non-contact power supply, the magnetic plate and the conductor plate are appropriately arranged to maintain the power transmission efficiency as high as possible and to be affected by the change of the magnetic field outside the device when supplying power. The present applicant has found that it is possible to suppress as much as possible. Hereinafter, the remarkable effects of the present invention will be described in detail.

  First, non-contact type power supply by a conventional housing configuration will be described with reference to FIGS. 6A, 6B, and 7. FIG. 6A and 6B are diagrams illustrating a magnetic field distribution around a coil formed when power is transmitted from the power transmission coil to the power reception coil using the principle of magnetic field resonance. In these drawings, the coils are arranged so that the power supply surfaces of the power transmission coil and the power reception coil face each other in the Z-axis direction (Z = 0 is located between the power transmission coil and the power reception coil). Each figure represents a magnetic field distribution in the XZ plane (Y = 0). Further, FIG. 6A shows a magnetic field distribution in a state in which the power receiving coil is disposed at the bottom of the vehicle as illustrated in FIG. 1 and an iron plate is disposed on the back side in the Z-axis direction of the power receiving coil. Moreover, FIG. 6B showed the magnetic field distribution in the state which does not provide an iron plate as a comparison object of the magnetic field distribution shown in FIG. 6A. The intensity of the magnetic field shown in these figures is represented by grayscale shading, which means that the darker the grayscale, the stronger the magnetic field intensity.

  6A and 6B, when the power receiving coil is installed at the bottom of the vehicle or the like, the magnetic field in the Z-axis direction is largely blocked by the presence of the iron plate of the conductive member. On the other hand, in an iron plate of a conductive member, eddy current is generated due to interference with a magnetic field, so that power transmission efficiency is greatly reduced. For example, the power transmission efficiency in the magnetic field distribution shown in FIG. 6B is 74.6%, while the power transmission efficiency in the magnetic field distribution shown in FIG. 6A is 15.7%.

FIG. 7 shows the transition of the magnetic field strength in the X-axis direction (that is, the external direction of the power supply device 1) in the form shown in FIGS. 6A and 6B. The horizontal axis in FIG. 7 represents the X-axis distance, the vertical axis represents the magnetic field strength, and the transition of the magnetic field strength corresponding to the mode shown in FIG. 6A is a black dot (a point represented by the expression “coil + iron plate”). The magnetic field intensity corresponding to the mode shown in FIG. 6B is represented by a white point (a point represented by the expression “only coil”). As is apparent from FIG. 7, when the power receiving coil is installed on the bottom of the vehicle or the like according to the conventional housing mode (that is, in the mode shown in FIG. 6A), X is more than when the power transmitting and receiving coils are simply opposed. The strength of the magnetic field formed in the axial direction increases. As described above, since the power transmission efficiency is extremely low in the mode shown in FIG. 6A as described above, it is necessary to increase the output on the power transmission side in order to supply desired power, and the magnetic field leaks in the X-axis direction. It is because the intensity | strength of becomes large. As a result, the X-axis distance is 600 m
Even if it becomes m, the magnetic field intensity there is in a state exceeding the magnetic field intensity (about 2 A / m) set as a safety standard.

  As described above, in the aspect of the housing of the power transmission / reception coil according to the prior art, there are many points to be reviewed from the viewpoint of power transmission efficiency and leakage of the magnetic field to the outside, and the housing configuration according to the present invention solves these problems. . Therefore, in the power supply device 1 formed by the power transmission unit 10 and the power reception unit 20 having the housing configuration shown in FIGS. 4 and 5, the magnetic field distribution in the XZ plane formed between the two units when supplying power is shown in FIG. Show. FIG. 9 shows the transition of the magnetic field strength in the X-axis direction (that is, the external direction of the power supply device 1) in the form shown in FIG. As for the display of each axis in FIG. 9, the horizontal axis represents the X-axis distance, and the vertical axis represents the magnetic field strength, as in FIG. Further, the transition of the magnetic field intensity corresponding to the embodiment shown in FIG. 8 (that is, the embodiment according to the present invention) is represented by a black dot (a point represented by the notation “coil + magnetic plate + conductor plate”), The magnetic field strength corresponding to the aspect shown in FIG. 6B (ie, the aspect without the housing) as a comparison target is represented by a white point (a point represented by the notation “coil only”).

  As is clear from FIG. 8, in the housing configuration according to the present invention, a relatively strong magnetic field distribution is not formed in the Z-axis direction beyond the power transmission unit 10 and the power reception unit 20. As is clear from FIG. 9, the magnetic field strength is about 0.3 A / m at the position of 500 mm corresponding to the housing ends of both units in the X-axis direction. Degree). As shown in FIG. 7, in the housing according to the prior art (the embodiment shown in FIG. 6A), the magnetic field strength at the same X-axis position is a little over 10 A / m, and thus the effect of the housing configuration according to the present invention is extremely characteristic. It can be understood that.

  Then, based on FIG. 10 and FIG. 11, the housing structure which concerns on this invention is demonstrated still in detail. The following description will be made based on the power transmission unit 10, but the description is similarly applied to the power receiving unit 20. FIG. 10 is a graph showing the transition of the magnetic flux density on the line L1 shown in FIG. 8, and this line L1 is a line parallel to the X axis passing on the surface of the magnetic body plate 11a of the power transmission unit 10. FIG. 11 is a graph showing the transition of the current density of the eddy current formed on the surface of the conductor plate 11b. In FIG. 10 and FIG. 11, the transition of the magnetic flux density and the transition of the eddy current density on the line L1 in the state where the magnetic plate 11a is not disposed are shown for comparison with the indication “no magnetic plate”. ing.

  In the housing configuration according to the present invention, as shown in FIGS. 4 and 5, the magnetic plate 11 a is arranged so as to overlap the conductor plate 11 b, so that the X corresponding to the power supply surface of the power transmission coil 15 as shown in FIG. 10. The magnetic flux density at the axial position (−150 mm to 150 mm) can be increased. The magnetic flux density gradually decreases from the X-axis position (X = 200 mm) corresponding to the outer peripheral end of the magnetic plate 11a to the vicinity of the X-axis position (X = 500 mm) corresponding to the outer peripheral end of the conductor plate 11b. Go. Here, when FIG. 11 is seen, in the X-axis position of the range in which the magnetic plate 11a exists, the presence of the magnetic plate 11a effectively suppresses the eddy current generated in the conductor plate 11b. I understand that Thus, by overlapping the magnetic plate 11a and the conductor plate 11b, it is possible to efficiently use the magnetic flux contributing to power supply without losing it as an eddy current, and as a result, according to the present invention. Simulation results show that the power transmission efficiency can be increased to 79.4% with the housing configuration.

Further, as shown in FIG. 11, at the X-axis position (200 mm to 500 mm) corresponding to the portion where only the conductor plate 11b is extended without the magnetic plate 11a, the housing configuration according to the present invention has the eddy current density. Is relatively high. This is because the presence of the magnetic plate 11a functions as a core, and as a result, the magnetic field strength at the X-axis position (200 mm to 500 mm) increases. Generation of eddy current in the conductor plate 11b means that a part of the magnetic field generated by the power transmission coil 15 is consumed as eddy current.
At the X-axis position (200 mm to 500 mm) corresponding to the portion where only 1b extends, the increase in the eddy current density is a position away from the power supply surface of the power transmission coil 15, thus reducing the power transmission efficiency. Does not have a significant effect, but rather contributes to reducing the strength of the magnetic field leaking outside the power supply device 1. The result is considered to result in the result shown in FIG.

  As described above, in the present invention, by forming the housing of the power transmission / reception coil by combining the magnetic plates 11a, 21a and the conductor plates 11b, 21b, the power transmission efficiency is maintained as high as possible and the magnetic field to the outside is maintained. It becomes possible to suppress the influence of the change as much as possible. In the above-described embodiment, the X-axis position corresponding to the portion where only the conductor plate 11b extends is set to 200 mm to 500 mm. However, this width is the strength of the magnetic field that allows leakage to the outside. What is necessary is just to set suitably according to. Further, the thicknesses of the magnetic plates 11a and 21a and the conductor plates 11b and 21b can be appropriately selected in consideration of the strength of the housing and the like. In particular, the magnetic plates 11a and 21a preferably have an appropriate thickness so that the magnetic flux passing therethrough is not saturated when power is supplied.

  Further, since the conductor plate 11b in the power transmission unit 10 and the conductor plate 21b in the power reception unit 20 are each formed of a conductive material, each of them is a structure installed on the road surface or a vehicle as a moving body shown in FIG. It may be formed in a shared state with the structure formed of a conductive material. That is, in the power transmission side unit 10, the structure made of the conductive material on the road surface is regarded as the conductor plate 11b, and the magnetic plate 11a, the resin cover 11c, and the power transmission coil 15 are disposed thereon. The steel plate body of the vehicle may be regarded as the conductor plate 21b, and the magnetic plate 21a, the resin cover 21c, and the power receiving coil 25 may be disposed thereon.

  In FIG. 3, as a representative example, a four-coil configuration with two coils on the power transmission side and two coils on the power reception side is illustrated, but the present invention is a magnetic field resonance between the power transmission coil 15 and the power reception coil 25. The number of coils is not limited to the above four-coil configuration. For example, a two-coil configuration including one power transmission side coil and one power receiving side coil may be employed, or a three coil configuration including one power transmission side coil and two power receiving side coils may be employed. The two coils on the power receiving side in the three-coil configuration are the first power receiving coil 25a and the second power receiving coil 25b that are connected by electromagnetic induction. FIG. 12 is a diagram showing an outline of a three-coil configuration in the present embodiment.

<Other examples>
Another embodiment of the housing structure according to the present invention will be described with reference to FIG. In the housing configuration shown in FIG. 13, in the power transmission unit 10, a circular central housing 110 is installed with respect to the power transmission coil 15, and a donut-shaped side housing is formed on the side of the central housing 110 so as to surround the entire circumference. 111 is arranged. The central housing 110 has a diameter of φ400 mm, and is formed by overlapping a magnetic member layer 110a made of a magnetic material and a conductive member layer 110b made of a conductive material, and the magnetic member layer 110a is disposed closer to the power transmission coil 15. The The side housing 111 has an inner diameter of φ400 mm and an outer diameter of φ1000 mm, and is formed of the same conductive member as the conductive member layer of the central housing 110. The substantially same housing configuration is also realized in the power receiving unit 20, and a central housing 210 having a magnetic member layer 210a and a conductive member layer 210b and a side housing 211 made of a conductive material are arranged. .

Even when the housing structure according to the present invention is formed by the central housing and the side housing shown in FIG. 13, the power transmission efficiency is kept as high as possible, and the influence of the change in the magnetic field to the outside is maintained as in the above-described embodiment. Can be suppressed as much as possible. From the viewpoint of leakage of the magnetic field to the outside, the gap provided between the central housing and the side housing is preferably as small as possible. However, as long as magnetic field leakage is allowed, the gap is appropriately sized. Can be adjusted. Further, the conductive member layers of the side housing and the central housing are not necessarily made of the same conductive material, and an appropriate conductive material may be selected. Furthermore, the thicknesses of the conductive member layers of the side housing and the central housing do not need to be the same, and may be appropriately designed.

DESCRIPTION OF SYMBOLS 1 Power supply apparatus 10 Power transmission unit 11a Magnetic board 11b Conductor board 15 Power transmission coil 17 Power transmission controller 20 Power reception unit 21a Magnetic body board 21b Conductor board 25 Power reception coil 27 Power reception controller 110, 210 Central housing 111, 211 Side housing

Claims (10)

A non-contact power supply unit that supplies power from a power source to a power supply destination in a non-contact manner,
A power receiving coil formed of any one of a power receiving coil that receives power on the power supply destination side in the non-contact power supply, or a power transmission coil that transmits power on the power source side in the non-contact power supply; and ,
A housing disposed on the opposite side of the coil for power supply in the non-contact power supply, having a surface area covering at least a power supply surface formed by the power supply coil, and a magnetic material A first housing formed of,
A housing disposed on the opposite side of the power supply coil across the first housing, having a surface area larger than the first housing in a direction along the power supply surface of the power supply coil, and being electrically conductive A second housing formed of a sexual material;
A non-contact power supply unit comprising: The outer peripheral end portion of the first housing extends outward from the outer peripheral end portion of the power feeding coil on the entire circumference thereof.
The contactless power supply unit according to claim 1. The outer peripheral end portion of the second housing extends outward from the outer peripheral end portion of the first housing in the entire periphery thereof.
The non-contact power supply unit according to claim 1 or 2. The non-contact power supply unit is a unit that supplies power to a battery of a mobile body as the power supply destination from the power source installed on the road surface.
The non-contact power supply unit according to any one of claims 1 to 3. The second housing is a member installed on the road surface and configured to be shared with a conductive member formed of a conductive material, or a main body member of the movable body and a conductive material. Constructed in a shared state with the formed conductive member,
The non-contact power supply unit according to claim 4. The area of the extended portion of the second housing existing between the outer peripheral end of the second housing and the outer peripheral end of the first housing is detected at a predetermined position on the side of the movable body when power is supplied. Is designed so that the magnetic field strength to be less than the predetermined reference strength,
The contactless power supply unit according to claim 4 or 5. A non-contact power supply unit that supplies power from a power source to a power supply destination in a non-contact manner,
A power receiving coil formed of any one of a power receiving coil that receives power on the power supply destination side in the non-contact power supply, or a power transmission coil that transmits power on the power source side in the non-contact power supply; and ,
A housing disposed on the opposite side of the coil for power supply in the non-contact type power supply, the magnetic member layer formed of a magnetic material and the conductive member layer formed of a conductive material And a central housing formed and arranged in order from the power supply coil side and covering the power supply surface formed by the power supply coil;
A side housing which is disposed on the side of the central housing in a direction along the power supply surface of the power supply coil and is formed of a conductive material;
A non-contact power supply unit comprising: The conductive member layer of the central housing and the side housing are formed of the same conductive member made of a conductive material.
The non-contact power supply unit according to claim 7. The non-contact power supply unit is a unit that supplies power to a battery of a mobile body as the power supply destination from the power source installed on the road surface.
The contactless power supply unit according to claim 7 or 8. A non-contact type of supplying power in a non-contact manner from a power source to a power supply destination, comprising at least two non-contact type power supply units according to claim 1. Power supply device,
Of the at least two contactless power supply units, at least one contactless power supply unit is a unit including the power feeding coil as a power receiving coil that receives power on the power supply destination side.
Of the at least two contactless power supply units, the remaining contactless power supply unit is a unit including the power feeding coil as a power transmission coil that performs power transmission on the power source side.
Non-contact power supply device.

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