JP2012105456A - Non-contact power supply system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-contact power supply system capable of preventing, in a simple configuration, electric power beyond a power capacity of a power receiver from being supplied from a power transmitter to the power receiver, for a plurality of types of power receivers having different power capacities.SOLUTION: The non-contact power supply system comprises: a power transmitter, having a primary coil, to receive electric power from the outside and to provide the primary coil with AC power; and a power receiver detachably connected to the power transmitter. The power receiver comprises; a secondary coil to supply a load with electric power induced through electromagnetic coupling with the primary coil when connected with the power transmitter; and a protrusion, having an insertion length corresponding to an amount of a power capacity of the power receiver, inserted into the power transmitter when the power transmitter and the power receiver are connected. The power transmitter comprises: an elastic member compressed by the protrusion when connected with the power receiver; a pressure detector to detect pressure of the elastic member; a current detector to detect an input current from the outside to the power transmitter; and a control unit to stop power supply to the primary coil when an input current exceeds a current threshold corresponding to a detected pressure.

Description

  The present invention relates to a non-contact power feeding system.

  As a background art of the present invention, in a device that feeds power from a power feeding head to a power receiving head in a non-contact manner, the primary core and secondary core of the coupling transformer can be individually separated, and the power feeding head and the power receiving head have a primary core. A secondary core is provided, and the primary core and the secondary core each have a primary winding and a secondary winding wound around the primary core and the secondary core, and means for detecting current flowing in the primary winding and the primary winding There is known a non-contact power feeding device that includes an overcurrent protection circuit on the power feeding head side that stops a current supplied to the primary winding when the current flowing through the coil becomes an overcurrent (see, for example, Patent Document 1). ).

  In addition, the primary side and the secondary side of the coupling transformer are individually accommodated and configured to be separable from each other, and the primary side unit and the secondary side unit are provided. In the power supply apparatus for supplying electric power to the unit in a non-contact manner using electromagnetic induction, the secondary unit includes transmission means for wirelessly transmitting signals relating to the voltage and current on the secondary side of the coupling transformer to the outside. There is also known a non-contact power feeding device including a receiving unit that receives the signal transmitted wirelessly by the primary unit and controls driving of the primary unit based on the signal (for example, Patent Document 2).

JP 2001-268823 A JP 2004-153879 A

  However, in the above-described device provided with a circuit for protecting the overcurrent by detecting the current of the primary winding on the power feeding head side, when a plurality of types of power receiving heads having different power capacities are selectively connected, There is a problem that the value of the current at which the overcurrent protection circuit is activated cannot be set corresponding to the power capacity on the power receiving head side.

  In addition, in the above-described device that wirelessly transmits the current and voltage on the secondary unit side to the primary unit, it is necessary to provide communication means and voltage / current detection means on the secondary unit, which complicates the circuit. Moreover, there is a problem that the size of the secondary unit becomes large.

  The present invention has been made in consideration of such circumstances, has a simple circuit configuration, and corresponds to the power capacity of the secondary side unit (power receiving device) up to 1 to the primary side unit (power transmission device). A non-contact power supply system is provided in which the secondary input current is automatically set and power supply to the secondary unit is stopped when the primary input current exceeds the set value.

  The present invention includes a power transmission device that has a primary coil, receives power from the outside, and supplies AC power to the primary coil; and a power reception device that is detachably coupled to the power transmission device. A secondary coil that supplies an electric power induced by electromagnetic coupling with the primary coil when coupled to the device to the load, and a power capacity of the power receiving device that is inserted into the power transmitting device when coupled with the power transmitting device and the power receiving device. A power transmission device including an elastic member that is compressed by the protrusion when coupled to the power receiving device, a pressure detector that detects a pressure of the elastic member, and an external device to the power transmission device. A non-contact power feeding system is provided that includes a current detector that detects the input current and a control unit that stops power feeding to the primary coil when the input current exceeds a current threshold corresponding to the detected pressure. .

  According to the present invention, the power capacity of the power receiving device is detected by the pressure detector as the compression pressure of the elastic member corresponding to the length of the protruding portion, and the input current to the power transmitting device corresponds to the current corresponding to the power capacity of the power receiving device. Since power supply to the primary coil is stopped when the threshold value is exceeded, the power receiving device can safely receive power corresponding to the power capacity with a simple configuration.

It is an electric circuit diagram of the non-contact electric power feeding system of this invention. It is a perspective view which shows the power transmission side core of a power transmission apparatus. It is a perspective view which shows the state with which the primary side bobbin which wound the primary coil was mounted | worn with the power transmission side core shown in FIG. It is a perspective view which shows the state which fixed the secondary side bobbin which wound the secondary coil to the power receiving side core of a power receiving apparatus. It is a top view which shows the coupling relationship of a primary coil and a secondary coil. It is AA arrow sectional drawing of FIG. It is BB arrow sectional drawing of FIG. It is explanatory drawing which shows the structure of the coupling member of a power transmission apparatus and a power receiving apparatus. It is explanatory drawing which shows operation | movement of the coupling member of a power transmission apparatus and a power receiving apparatus.

  A non-contact power feeding system of the present invention includes a power transmission device that has a primary coil, receives power from the outside, and supplies AC power to the primary coil, and a power reception device that is detachably coupled to the power transmission device, The power reception device is inserted into the power transmission device when the power transmission device and the power reception device are coupled, and the secondary coil that supplies the load with the secondary coil that is electromagnetically coupled with the primary coil when the power reception device is coupled. The power transmission device includes an elastic member that is compressed by the protrusion when coupled to the power receiving device, a pressure detector that detects the compression pressure of the elastic member, and an external device. A current detector that detects an input current to the power transmission device, and a control unit that stops power supply to the primary coil when the input current exceeds a current threshold value corresponding to the detected pressure.

  The power transmission device includes an oscillation circuit that converts electric power received from the outside into AC power and supplies it to the primary coil, and the control unit stores the current threshold value, and stores the current threshold value from the storage unit. And a control circuit that stops the output of the oscillation circuit when the current detected by the current detector exceeds the current threshold value.

  The storage unit may include a table representing current threshold values for different detected pressures, and the control circuit may read the current threshold values from the table based on the detected pressure of the pressure detector.

  The power receiving device includes a bobbin that winds the secondary coil, and the bobbin preferably forms the protruding portion. However, the protruding portion may be configured by another member.

  The control circuit may have a function of outputting an oscillation circuit when the pressure detector detects some pressure.

The power transmission device has a first core, the power reception device has a second core, and when the power transmission device and the power reception device are coupled, a transformer core is formed by the first core and the second core, and the transformer core A transformer in which a primary coil and a secondary coil are wound around each other may be configured.
The power transmission device may include a lock member locking hole on a surface facing the power reception device, and the power reception device may include a lock member at a corresponding position. Further, an elastic member may be provided so that the power receiving device is discharged from the power transmitting device by the repulsive force of the elastic member except when the power receiving device is completely coupled (locked) to the power transmitting device. In this case, power feeding in a state where the power receiving device and the power transmitting device are not sufficiently coupled can be prevented.

Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings.
FIG. 1 is an electric circuit diagram of the contactless power feeding system of the present invention.
As shown in FIG. 1, the non-contact power feeding system of the present invention includes a power transmitting device 1 and a power receiving device 2.

The power transmission device 1 includes an oscillation circuit (DC / AC converter) 11 that converts a DC voltage from a DC power supply 16 into an AC voltage, a primary coil 10 to which the converted AC voltage is applied, and a primary coil 10 wound. The pressure of a rotating power transmission side core (iron core) 18, a control circuit 12 that controls the oscillation circuit 11, and an elastic member (described later) that is pressed when the power reception device 2 is inserted (coupled) into the power transmission device 1. A pressure detector 14 for detecting, a current detector 15 for detecting an input current to the power transmission device 1, and a storage unit 13 for storing a current threshold value for stopping power feeding are provided.
The DC power source 16 is a power generation type DC power source such as a solar power generation device, a wind power generation device or a fuel cell, or a stabilized DC power source in which the voltage of the AC power source is stabilized to a predetermined voltage by a DC power converter, Alternatively, it is an AC power source conversion type DC power source obtained by rectifying an AC power source acquired from a commercial system and converting it to DC.

The power receiving device 2 includes a secondary coil 20 that electromagnetically couples with the primary coil 10 to receive power, and a rectifier circuit 21 that converts an AC voltage induced in the secondary coil 20 by electromagnetic induction into a DC voltage. And a capacitor 22 for smoothing the converted DC voltage and applying it to the load (electrical device) 3, and for electromagnetically coupling the primary coil 10 and the secondary coil 20 when the power receiving device 2 is coupled to the power transmitting device 1. And a power receiving side core 23 that forms a magnetic path.
The load 3 uses a DC device such as a personal computer, a mobile phone, or a PDA, but it is converted into AC by a DC / AC converter, so that an AC device such as a refrigerator, a washing machine, a TV, an air conditioner, a copier, or a facsimile machine is used. Can be used. Of course, when a refrigerator, a washing machine, a television, an air conditioner, a copier, or a facsimile machine is operated by a DC power source, the voltage may be converted into a load.

  The oscillation circuit 11 includes a half-bridge converter 11a including transistors QA and QB, diodes DA and DB, and capacitors CA and CB, and a pulse generator that generates a pulse signal to turn the transistors QA and QB on / off. 11b.

  The pulse generator 11b generates a high frequency pulse of several tens of kHz, and upon receiving a signal from the control circuit 12, changes the ratio of the ON period to the pulse period, that is, the duty ratio, and controls the AC voltage output from the converter 11a. It has become.

FIG. 2 is a perspective view showing the power transmission side core 18, and FIG. 3 is a perspective view showing the primary coil 10 attached to the power transmission side core 18. As shown in FIG. 2, the power transmission side core 18 includes a cylindrical central core 18a and an outer peripheral core 18b, and the primary coil bobbin 19 around which the primary coil 10 is wound is concentric with the central core 18a as shown in FIG. It is installed.
On the other hand, as shown in FIGS. 4 and 6, the secondary coil 20 wound around the secondary coil bobbin 25 is covered and fixed to the power receiving side core 23 by the secondary coil cover 24.

  FIG. 5 is a top view showing a coupling relationship between the primary coil 10 and the secondary coil 20 when the power receiving device 2 is inserted (coupled) into the power transmitting device 1, and FIG. 6 is a cross-sectional view taken along the line AA in FIG. 7 is a cross-sectional view taken along the line BB in FIG.

When the power receiving device 2 is coupled to the power transmitting device 1, as shown in FIG. 6, a closed magnetic circuit is formed by the power transmitting side core 18 and the power receiving side core 23, and the primary coil 10 and the secondary coil 20 are formed in the central core 18a. A transformer is constructed in which and are wound.
In the present embodiment, the shape of the power transmission side core 18 and the power reception side core 23 is a so-called PQI shape, but the shape of the core in the present invention is not limited to this, and may be an EIR shape or an EI shape.

  As shown in FIGS. 5 and 6, the power transmission device 1 is supported so as to be able to move in the longitudinal direction of the bobbin 25 (arrows X <b> 1 and X <b> 2) while contacting the pressure detector 14 and the tip of the secondary coil bobbin 25. A π-shaped moving member 31 and a coil spring 32 that is held between the pressure detector 14 and the moving member 31 and biases the moving member 31 in the arrow X1 direction.

  A plurality of types of power receiving devices 2 having different power capacities (power receiving capabilities) can be selectively coupled to the power transmitting device 1, and the size of the power receiving device 2 is determined according to the power receiving capability, so that the power receiving capability is small. Can be reduced in weight. Moreover, the power receiving apparatus 2 can adjust the output voltage by changing the number of turns of the secondary coil 20, and can supply the optimal voltage to the apparatus side. Here, the size of the power receiving device 2 is represented by a protruding length corresponding to the power capacity of the power receiving device 2 of the protruding portion provided in the power receiving device 2.

  In this embodiment, the secondary coil bobbin 25 around which the secondary coil 20 is wound forms the protruding portion, and the size of the power receiving device 2 is the protruding length of the secondary coil bobbin 25, that is, the insertion length into the power transmission device 1. Means L (FIG. 6). Therefore, the insertion length L of the secondary coil bobbin 25 of the power reception device 2 having a high power capacity (power reception capability) is long, and the insertion length L of the secondary coil bobbin 25 of the power reception device 2 having a low power capacity is short.

  When the power receiving device 2 is inserted (coupled) into the power transmitting device 1, the coil spring 32 is compressed in the direction of the arrow X <b> 2 by the moving member 31 and applies a pressing force to the pressure detector 14. Therefore, if the size of the power receiving device 2, that is, the insertion length L of the secondary coil bobbin 25 is long, the pressing force of the coil spring 32 increases, and as a result, the pressure detected by the pressure detector 14 increases.

The storage unit 13 (FIG. 1) includes a ROM and a RAM. As shown in Table 1, a table representing a relationship between the detected pressure, the insertion length L of the secondary coil bobbin 25, and the current threshold is stored in advance in the ROM. ing.

  In such a configuration, when the power transmitting device 1 and the power receiving device 2 are coupled, the pressure detector 14 detects the pressure of the coil spring 32. The control circuit 12 reads the current threshold value corresponding to the detected pressure from the conversion table of Table 1, and stores it in the RAM of the storage unit 13.

  The control circuit 12 causes the oscillation circuit 11 to continuously oscillate with a pulse having a predetermined duty ratio when normal. As a result, an AC voltage is applied to the primary coil 10, an AC voltage is induced in the secondary coil, the induced AC voltage is rectified by the rectifier circuit 21, smoothed by the smoothing capacitor 22, and applied to the load 3. .

  The current input current value is detected by the current detector 15, and the control circuit 12 compares the input current value with the current threshold value stored in the RAM of the storage unit 13. When the power receiving device 2 and the connected load 3 are operating normally, the input current value does not exceed the current threshold value defined in the conversion table, and power feeding is continued.

  If for some reason an abnormality occurs in the power receiving device 2 or the connected load 3 (for example, a short circuit) and a current exceeding the power receiving capacity flows through the power receiving device 2, the control circuit 12 receives the input current in the RAM of the storage unit 13. It is detected that the held current threshold is exceeded, and the output of the pulse generator 11b is stopped. Then, the oscillation circuit 11 stops the output and power supply to the power receiving device 2 is stopped, so that overcurrent protection of the power receiving device 2 and the load 3 is realized.

Here, the relationship between the power receiving capability of the power receiving device 2, that is, the power capacity (W), and the insertion length L of the secondary coil bobbin 25 will be described.
For example, the AC voltage applied to the primary coil 10 of the power transmission device 1 is 100 V, and the number of turns of the primary coil 10 is 100 turns. In addition, the power capacities of the two power receiving apparatuses 2 having different power receiving capabilities (power capacities) are
(A) 40W (20V x 2A)
(B) 5W (5V x 1A)
Since the coil turns ratio is equal to the voltage ratio, the number of turns is (a) 100V: 20V = 100 turns (primary coil turns): 20 turns (secondary coil turns).
(B) 100V: 5V = 100 turns (number of primary coil windings): 5 turns (number of secondary coil windings)
It becomes.

  Further, since the wire diameter of the secondary coil winding is determined by the allowable current capacity, the coil diameter can be reduced with a small current capacity. As a result, the size of the secondary coil bobbin 25, that is, the insertion length L is determined in accordance with the size of the power capacity (power reception capability).

Further, the control circuit 12 detects whether or not the power receiving device 2 is coupled to the power transmitting device 1 using the pressure detector 14. That is, when the pressure detector 14 detects any pressure (pressure greater than 0 kg / cm ² in Table 1), the control circuit 12 determines that the power receiving device 2 is coupled to the power transmitting device 1.
Then, the control circuit 12 drives the pulse generator 11 b and applies an AC voltage to the primary coil 10.

On the other hand, when the pressure detector 14 does not detect any pressure, the control circuit 12 determines that the power receiving device 2 is not coupled to the power transmitting device 12 and does not drive the pulse generator 11b.
Therefore, in this case, no AC voltage is applied to the primary coil 10, and power consumption in the circuit can be reduced.

  8 and 9 are explanatory views showing the configuration and operation of the coupling member of the power transmission device 1 and the power reception device 2. As shown in these drawings, the power transmission device 1 includes lock member engagement holes 33 a and 33 b on the surface facing the power reception device 2.

  On the other hand, the power receiving device 2 includes lock members 34a and 34b at positions corresponding to the lock member locking holes 33a and 33b, respectively. The lock members 34a and 34b include lock claws 35a and 35b, plate springs 36a and 36b that elastically support the lock claws 35a and 35b, and push buttons 37a and 37b respectively provided on the plate springs 36a and 36b. Prepare.

  In such a configuration, as shown in FIG. 8, when the power receiving device 2 is attached to the power transmitting device 1 in the direction of arrow C, the moving member 31 is pressed and moved in the direction of arrow C by the secondary coil bobbin 25. Then, the lock members 34 a and 34 b of the power receiving device 2 are inserted into the lock member locking holes 33 a and 33 b of the power transmission device 1. When they are completely inserted, as shown in FIG. 9, the lock claws 35 a and 35 b are respectively locked in the lock member locking holes 33 a and 33 b, and the power receiving device 2 is completely coupled (locked) to the power transmitting device 1. The

  When the power receiving device 2 is detached from the power transmitting device 1, the push buttons 37a and 37b are pushed to release the lock claws 35a and 35b, and the lock members 34a and 34b are released from the lock member lock holes 33a and 33b. Is pulled out in the direction opposite to arrow C.

  Further, when the power receiving device 2 is not completely locked to the power transmitting device 1, the coupling between the primary coil 10 and the secondary coil 20 becomes insufficient, resulting in a lot of loss and a risk of heat generation. However, in that case, the repulsive force of the coil spring 32 (FIG. 5) is applied to the power receiving device 2 via the moving member 31, and the power receiving device 2 is discharged from the power transmitting device 1, so that safety is ensured.

DESCRIPTION OF SYMBOLS 1 Power transmission apparatus 2 Power receiving apparatus 3 Load 10 Primary coil 11 Oscillation circuit 12 Control circuit 13 Memory | storage part 14 Pressure detector 15 Current detector 16 DC power supply 18 Power transmission side core 18a Central core 18b Outer core 19 Primary coil bobbin 20 Secondary coil 21 Rectifier 22 Smoothing Capacitor 23 Power Receiving Core 24 Secondary Coil Cover 25 Secondary Coil Bobbin 31 Moving Member 32 Coil Spring 33a Lock Member Lock Hole 33b Lock Member Lock Hole 34a Lock Member 34b Lock Member 35a Lock Claw 35b Lock Claw 36a Leaf spring 36b Leaf spring 37a Push button 37b Push button

Claims (7)

  A power transmission device that includes a primary coil and receives power from the outside and supplies AC power to the primary coil; and a power reception device that is detachably coupled to the power transmission device. The power reception device is coupled to the power transmission device. Insertion length corresponding to the magnitude of the power capacity of the power receiving device inserted into the power transmitting device when the power transmitting device and the power receiving device are combined with the secondary coil that sometimes supplies the load with the power induced by electromagnetic coupling with the primary coil. The power transmission device includes an elastic member that is compressed by the protrusion when coupled to the power receiving device, a pressure detector that detects the pressure of the elastic member, and an input current from the outside to the power transmission device. A non-contact power feeding system comprising: a current detector to detect; and a control unit that stops power feeding to the primary coil when the input current exceeds a current threshold value corresponding to the detected pressure.   The power transmission device includes an oscillation circuit that converts electric power received from the outside into AC power and supplies it to the primary coil, and the control unit stores the current threshold value, and stores the current threshold value from the storage unit. The non-contact electric power feeding system according to claim 1, further comprising: a control circuit that reads and stops the output of the oscillation circuit when the detected current of the current detector exceeds a current threshold value.   The non-contact power feeding system according to claim 2, wherein the storage unit includes a table representing current threshold values for different detected pressures, and the control circuit reads the current threshold value from the table based on the detected pressure of the pressure detector.   The non-contact power feeding system according to claim 1, wherein the power receiving device includes a bobbin that winds the secondary coil, and the bobbin forms the protruding portion.   The contactless power supply system according to claim 2, wherein the control circuit has a function of outputting an oscillation circuit when the pressure detector detects pressure.   The power transmission device includes a lock member locking hole and a lock detection unit on a surface facing the power reception device, each power reception device includes a lock member at a corresponding position, and receives power except when the power reception device is completely locked to the power transmission device. The contactless power feeding system according to claim 1, further comprising a mechanism that mechanically separates the device from the power transmission device.   The power transmission device has a first core, the power reception device has a second core, and when the power transmission device and the power reception device are coupled, a transformer core is formed by the first core and the second core, and the transformer core The contactless power supply system according to claim 1, wherein a transformer in which a primary coil and a secondary coil are wound around is configured.

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