JPH09266121A - Non-contact type power supply - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily identify the presence of an opposite secondary coil by constructing a primary coil with a plurality of primary windings wound such that magnetic fluxes produced in an O shaped closed magnetic path core are canceled out each other, and constructing the secondary coil with secondary windings wound on an I shaped open magnetic path core. SOLUTION: A primary coil 1 to which an rf current is supplied and a secondary coil 2 which is mounted in a different box from the primary coil 1 are opposed. The primary coil 1 is constructed with a plurality of primary windings 11 wound such that magnetic fluxes produced in an O shaped closed magnetic path core 10 are canceled out each other, and the secondary coil 2 is constructed with a secondary winding 12 wound on an I shaped open magnetic path core 20. Hereby, the primary coil 1 is short-circuited when the secondary coil 2 is not opposed thereto, so that the presence of the opposite to the secondary coil 2 is easily identified.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-contact type power supply device that utilizes electromagnetic induction to transmit power from independent primary coils to secondary coils.

[0002]

2. Description of the Related Art Conventionally, a non-contact type power supply device has been disclosed in Japanese Patent Laid-Open No. 54-150645. Further, as the disclosure of the shapes of the primary coil and the secondary coil, which are the power transmission parts, is disclosed in Japanese Patent Laid-Open No. 6-2254.
82 publication. FIG. 9 shows a configuration of a primary coil and a secondary coil of a conventional non-contact power supply device.
In (a), a primary coil and a secondary coil are wound around an E-shaped core, and in (b), the primary coil is C-shaped and the secondary coil is I-shaped. In both cases, when the high-frequency current flowing in the primary coil is in the direction shown in the figure, the magnetic flux generated in each core is as shown by the broken line in the figure, and the voltage induced in the secondary coil is rectified to supply power to the load. To do.

[0003]

In such a non-contact power supply device, the secondary coil faces the primary coil and the secondary coil faces the primary coil for power transmission. The problem was to distinguish it from the case where it is not, or the case where an object other than the secondary coil, especially a metal object is facing. Also, since the core of the primary coil is an open magnetic circuit,
Another problem is how to prevent noise due to leakage flux generated when the secondary coil does not face the primary coil.

According to the present invention, in such a non-contact type power supply device, when the secondary coil does not face the primary coil, generation of leakage magnetic flux is suppressed and the secondary coil faces the primary coil. The purpose is to provide a structure that can be easily distinguished from the case where it is used and the case where it is not used.

[0005]

In order to solve this problem, in a non-contact type power supply device of the present invention, a primary coil is wound around an O-shaped closed magnetic circuit core so that magnetic fluxes generated by each other cancel each other out. The secondary coil is composed of a plurality of primary windings, and the secondary coil is composed of a secondary winding wound around an I-shaped open magnetic circuit core.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS.

(Embodiment 1) FIG. 1 is a block diagram of a non-contact type power supply device of the present invention. In FIG. 1, 1 is a primary coil, a primary core 10, a first primary winding 11 , The second one
It is composed of the secondary winding 12. The primary core 10 is an O-shaped closed magnetic circuit, and the primary windings 11 and 1 are provided on the opposing magnetic legs, respectively.
2 is wound and the primary windings 11 and 12 are connected in series. A secondary coil 2 is composed of a secondary core 20 and a secondary winding 21. The secondary core 20 has an I shape, and a secondary winding 21 is wound around the secondary core 20. Reference numeral 3 is a high frequency AC power supply, which is connected to the primary coil 1 and supplies a high frequency current. A rectifier circuit 4 is connected to the secondary coil 2 to rectify the high frequency AC voltage induced in the secondary coil 2 and supply it to the load 5 as a DC output voltage. A current limiting circuit 6 limits the current supplied from the high frequency AC power source 3 to the primary coil 1 so as not to become excessive. Also,
FIG. 2 is a configuration diagram when the secondary coils 2 do not face each other.

The operation of the non-contact type power supply device configured as described above will be described below. High frequency AC power supply 3
The high-frequency current supplied from the first primary winding 11 and the second primary winding 11
Flowing through the primary winding 12 of the. When this high-frequency current is in the direction of the arrow in FIG. 1, the magnetic flux generated by the first primary winding 11 is generated as shown by the solid line in the primary core 10. Similarly the second one
The magnetic flux generated by the secondary winding 12 is generated as shown by the broken line in the primary core 10, and these magnetic fluxes pass through the secondary core 20. Therefore, a voltage is induced in the secondary coil 2 and is supplied to the load 5 via the rectifier circuit 4.

Next, when the secondary coils 2 do not face each other as shown in FIG. 2, when the high frequency current is in the direction of the arrow in FIG. 2, the magnetic flux generated by the first primary winding 11 is in the primary core 10. It occurs as shown by the solid line inside. Similarly, the magnetic flux generated by the second primary winding 12 is generated as shown by the broken line in the primary core 10,
These magnetic fluxes cancel each other out. Therefore, the primary coil 1 is short-circuited, and the current limiting circuit 6 operates to limit the current from the high frequency AC power supply 3. At this time, the magnetic fluxes generated in the primary coil 1 cancel each other out as described above, and since the primary core 10 is a closed magnetic circuit, almost no leakage magnetic flux is generated.

As shown in FIG. 1, the primary coil 1
In many cases, it is difficult to form the structure in which the I-shaped secondary coil 2 can be inserted into the O-shaped core because of the shape restriction of the entire non-contact power supply device including the housing. However, the present invention can be implemented with a structure as shown in FIG. 3 in the case where the primary side and the secondary side of the non-contact type power supply device have respective planar facing casing surfaces 71 and 72. 3 (a) is a structural drawing, (b)
And (c) are a front view and a side view, respectively. Since it becomes complicated, the housing surfaces 71 and 72 are omitted in (a).

Although the means for supplying the high frequency current to the primary coil 1 has been described as the high frequency AC power source 3, it is composed of the input DC power source 30 and the switching means 31, as shown in FIG. It is also possible to implement the above DC voltage even if the switching means 31 chops at a high frequency.

The current limiting circuit 6 has been used as a means for limiting the high frequency current flowing through the primary coil 1 when the secondary coils 2 are not facing each other.
As shown in (a), there is a method in which a high-frequency current is detected by a current detecting means such as a resistor 60, and when the current is about to exceed a predetermined value, the transistor 61 turns off the switching means 31. Other current limiting circuits can also be implemented. Further, as shown in FIG. 5B, when the inductor 62 is connected in series with the primary coil 1 and the secondary coil 2 does not face each other, the primary coil 1 is short-circuited and input to the inductor 62. There is also a method in which the detection circuit 63 detects that a voltage is applied and the switching means 31 is turned off. One of the effects of the present invention is that it is possible to detect that the secondary coils 2 are not facing each other by utilizing the fact that the primary coil 1 is in a short-circuited state.

(Embodiment 2) FIG. 6 shows a structure of a non-contact type power supply device of the present invention in which the primary side and the secondary side respectively have planar housing surfaces facing each other. 3 is the same as that of FIG.
The same number was given. The difference from the structure of FIG. 3 is that the shape of the secondary core is H-shaped.

The operation of the primary and secondary coils of the non-contact type power supply device configured as described above will be described below. When the direction of the high-frequency current is the direction of the arrow in FIG. 6, the magnetic flux generated by the high-frequency current flowing through the primary coil 1 is as shown by the broken line. That is, compared to the structure of FIG.
Since the facing area between the secondary core 10 and the secondary core 20 increases,
Magnetic flux leakage is reduced. Therefore, the magnetic coupling between the primary coil 1 and the secondary coil 2 becomes close, and highly efficient power transmission becomes possible.

(Embodiment 3) FIG. 7 shows the structure of the non-contact type power supply device of the present invention in which the primary side and the secondary side have respective concavo-convex facing casing surfaces 73 and 74.
In FIG. 3, the same numbers as in FIG. 3 are given to the components that operate in the same manner as in the first embodiment. The difference from the structure of FIG. 3 is that the unwound magnetic legs of the primary core 10 are projected to the secondary side. 7 (a) is a structural drawing, (b)
Is a side view thereof. The housing surfaces 73 and 74 are omitted in FIG.

The operation of the primary and secondary coils of the non-contact type power supply device configured as described above will be described below. When the direction of the high-frequency current is the direction of the arrow in FIG. 7, the magnetic flux generated by the high-frequency current flowing through the primary coil 1 is as shown by the broken line. That is, in the case where uneven structures are allowed on the opposing casing surfaces on the primary and secondary sides,
Although the magnetic coupling is similar to the structure in which the I-shaped secondary coil 2 can be inserted into the O-shaped core of the primary coil 1 as shown in FIG. 1, the projected area of the primary coil 1 can be made smaller, and Miniaturization is possible.

(Embodiment 4) FIG. 8 shows the structure of the non-contact type power supply device of the present invention in which the primary side and the secondary side have respective concavo-convex facing casing surfaces 75 and 76.
In FIG. 7, the same numbers as in FIG. 7 are assigned to the components that operate in the same manner as in the third embodiment. The difference from the structure of FIG. 7 is that the shape of the secondary core is H-shaped.
FIG. 8A is a structural view and FIG. 8B is a side view thereof. The housing surfaces 75 and 76 are omitted in FIG.

The operation of the primary and secondary coils of the non-contact type power supply device configured as described above will be described below. When the direction of the high-frequency current is the direction of the arrow in FIG. 8, the magnetic flux generated by the high-frequency current flowing through the primary coil 1 is as shown by the broken line. That is, compared to the structure of FIG.
Since the facing area between the secondary core 10 and the secondary core 20 increases,
Magnetic flux leakage is reduced. Therefore, the magnetic coupling between the primary coil 1 and the secondary coil 2 becomes close, and highly efficient power transmission becomes possible.

In the first to fourth embodiments, the first
The primary winding 11 and the second primary winding 12 are connected in series. However, if the magnetic fluxes generated when the secondary coils 2 do not face each other are in the directions canceling each other, they are connected in parallel. But it can be implemented.

[0020]

As described above, according to the present invention, when the secondary coils do not face each other, the primary coil is short-circuited, so that the presence or absence of the secondary coil can be easily identified and the primary coil can be easily identified. Since the core is a closed magnetic circuit, there is an advantageous effect that almost no leakage magnetic flux is generated.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a non-contact type power supply device according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a non-contact power supply device when the secondary coils are not opposed to each other in FIG.

FIG. 3A is a structural view in the case where the opposing casing surfaces on the primary and secondary sides are flat; FIG. 3B is a front view of FIG. 3A; and FIG. 3C is a side view of FIG.

FIG. 4 is a circuit diagram showing a high frequency AC power supply 3.

5A is a circuit diagram showing a current limiting circuit 6, and FIG. 5B is a circuit diagram showing a means other than the current limiting circuit 6.

FIG. 6 is a structural diagram of a non-contact type power supply device according to another embodiment of the present invention in which the opposing casing surfaces on the primary and secondary sides are flat.

FIG. 7 (a) is a non-contact type power supply device according to another embodiment of the present invention, and FIG. 7 (b) is a structural diagram when the opposing casing surfaces on the primary and secondary sides are uneven. ) Side view

FIG. 8A is a non-contact type power supply device according to another embodiment of the present invention, and FIG. 8B is a structural diagram when the opposing casing surfaces on the primary and secondary sides are uneven. ) Side view

9A is a configuration diagram of a conventional non-contact power supply device, and FIG. 9B is a configuration diagram of a conventional non-contact power supply device.

[Explanation of symbols]

 1 Primary coil 2 Secondary coil 3 High frequency AC power supply 4 Rectifier circuit 5 Load 6 Current limiting circuit 10 Primary core 11 First primary winding 12 Second primary winding 20 Secondary core 21 Secondary winding

Claims (5)

[Claims] 1. A primary coil supplied with a high frequency current,
In a non-contact type power supply device in which a secondary coil mounted in a housing different from this primary coil is opposed to transmit electric power from the primary coil to the secondary coil, the primary coil is The secondary coil is wound around an I-shaped open magnetic circuit core so that the magnetic fluxes generated in the closed magnetic circuit core cancel each other, and the secondary coil is wound around an I-shaped open magnetic circuit core.
A non-contact power supply device comprising a secondary winding. 2. The non-contact type power supply device according to claim 1, wherein the secondary coil is composed of a secondary winding wound around a middle magnetic leg of an H-shaped open magnetic circuit core. 3. The non-contact type power supply device according to claim 1, wherein the core of the primary coil has a shape in which a magnetic leg that is not wound protrudes in the secondary side direction. 4. The non-contact power supply device according to claim 3, wherein the secondary coil is composed of a secondary winding wound around a middle magnetic leg of an H-shaped open magnetic circuit core. 5. A high frequency current supplied to the primary coil is limited or cut off by detecting that the primary coil is short-circuited when the secondary coil does not face the primary coil. The non-contact power supply device according to claim 1, which has a function.