JP3478114B2 - Secondary side power receiving circuit of non-contact power supply equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a secondary side power receiving circuit of a contactless power feeding facility.

[0002]

2. Description of the Related Art An example of a conventional secondary side power receiving circuit of a contactless power feeding facility will be described with reference to FIG. The secondary-side power receiving circuit is provided with a coil 2 facing the primary-side induction line 1 for flowing a high-frequency current, and a capacitor 3 forming a resonance circuit that resonates at the frequency of the induction line 1 together with the coil 2 is connected to the coil 2. A rectifier circuit 4 is connected to the capacitor 3, and a constant voltage control circuit 5 for controlling the output voltage VDC to the reference voltage VE is connected to the rectifier circuit 4. The load 6 is connected to the constant voltage control circuit 5, and the constant voltage control circuit 5 supplies power to the load 6.

The constant voltage control circuit 5 includes a current limiting coil 7 and a voltage generator 8 for generating the reference voltage VE.
And a comparator 9 that compares the output voltage VDC with the reference voltage VE of the voltage generator 8, and the output voltage VDC is the reference voltage V E.
It is composed of an output adjusting transistor 10 which is turned on by a comparator 9 when E exceeds E, a diode 11 and a capacitor 12 which form a filter. The reference voltage VE is set to a high voltage assuming that the full load 6 is being supplied with power. The power of the load 6 is the working voltage VD
The larger C, that is, the reference voltage VE, becomes larger.

With the configuration of the constant voltage control circuit 5, when the load 6 decreases, the output voltage VDC rises and the output voltage VDC rises.
When the voltage exceeds the reference voltage VE, the comparator 9 turns on the transistor 10 to lower the output voltage VDC,
The output voltage VDC is maintained at the reference voltage VE.

[0005]

However, in such a secondary side power receiving circuit of the conventional contactless power feeding equipment, when the transistor 10 is turned on, the electric charge accumulated in the capacitor 3 (the coil 2 in the resonance state). And the energy of capacitor 3)
Was consumed by the coil 7 and the transistor 10, resulting in a large loss. Since the charge of the capacitor 3 is stored when the transistor 10 is off, when the reference voltage VE is high, the charge stored in the capacitor 3 is large and the energy loss is large.

Therefore, an object of the present invention is to provide a secondary side power receiving circuit of a contactless power feeding facility capable of reducing energy loss.

[0007]

In order to achieve the above-mentioned object, the secondary side power receiving circuit of the contactless power feeding equipment of the first aspect of the present invention has a coil facing a primary side induction line through which a high frequency current flows. Provided with this coil, a capacitor forming a resonance circuit that resonates at the frequency of the induction line together with the coil is connected,
Connect a rectifier circuit to this capacitor,
A secondary side power receiving circuit of a contactless power feeding facility, wherein a constant voltage control circuit for controlling an output voltage to a reference voltage is connected, and the constant voltage control circuit supplies power to a load. An output adjusting first transistor that is turned on when the reference voltage is exceeded, a second transistor is connected between the output terminals of the rectifier circuit, and a current limiting coil is provided between the first transistor and the second transistor. Intervening,
In order to make the output voltage of the constant voltage control circuit constant, when the first transistor is turned on, after a predetermined time,
Is configured to be turned off the first transistor while turning on the second transistor, it is characterized in that does not flow at all times current to the current limit for the coil.

With the above configuration, the electric charge accumulated in the capacitor is accumulated in the current limiting coil when the first transistor is turned on, and when the second transistor is turned on and the first transistor is turned off, The electric charge stored in the current limiting coil is output to the load, and thus the loss can be reduced. In addition,
The current capacity of the current limiting coil can be reduced by eliminating the constant current flow to the coil.

The secondary side power receiving circuit of the contactless power feeding equipment of the second aspect of the present invention is provided with a coil facing the primary side induction line through which a high frequency current flows, and this coil resonates with the coil at the frequency of the induction line. Connect a capacitor that forms a resonance circuit, connect a rectifier circuit to this capacitor, connect a constant voltage control circuit that controls the output voltage to the reference voltage, and feed the load from this constant voltage control circuit. A secondary side power receiving circuit of a contactless power feeding facility, wherein the constant voltage control circuit includes a first transistor for output adjustment which is turned on when the output voltage exceeds a reference voltage, and one input of the rectifier circuit. A third transistor is connected between the end and one output end of the rectifier circuit, and a fourth transistor is connected between the other input end of the rectifier circuit and the one output end of the rectifier circuit. Tiger A current limiting coil is provided between the transistors to keep the output voltage of the constant voltage control circuit constant, so that when the first transistor is turned on, the third transistor and the fourth transistor are turned on after a predetermined time. And a configuration in which the first transistor is turned off
However , the current limiting coil is not always supplied with current .

With the above configuration, the electric charge accumulated in the capacitor is accumulated in the current limiting coil when the first transistor is on, turning on the third transistor and the fourth transistor and turning off the first transistor. At this time, the electric charge accumulated in the current limiting coil is output to the load, and the loss can be reduced. In addition, the current capacity of the current limiting coil can be reduced by eliminating the constant flow of current through the current limiting coil.

The secondary side power receiving circuit of the contactless power feeding equipment of the third invention is the secondary side power receiving circuit of the contactless power feeding equipment of the first invention or the second invention, wherein the current limiting coil and the first A second coil is interposed between the transistors, and a connection point between the current limiting coil and the second coil is connected to an output terminal of the constant voltage control circuit.

With the above structure, when the first transistor is turned on, the current flowing through this transistor can be reduced, and the current capacity of the first transistor can be reduced.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. It should be noted that the same configurations as those of the conventional example shown in FIG. (Embodiment 1) FIG. 1 is a circuit configuration diagram of a secondary side power receiving circuit of a contactless power feeding facility according to Embodiment 1 of the present invention.

In the secondary side power receiving circuit of the first embodiment, the second transistor 21 is connected between the positive output terminal and the negative output terminal of the rectifying circuit 4, and the constant voltage control circuit 5'is further provided with a comparator. A timer 22 is provided which starts counting when the output signal of 9 is turned on. The timer 22 turns on the output signal when the count value reaches a preset count value (set time), and turns on the second transistor 21 by the on output signal. Further, a logical product circuit (AND circuit) 23 is provided in the constant voltage control circuit 5 ', and when the output signal of the comparator 9 is on and the output signal of the timer 22 is off, the output adjusting transistor 10 is turned on. There is. The set time of the timer 22 is a time for the voltage of the capacitor 3 to fall sufficiently to a predetermined voltage, and is set by the characteristics of the capacitor 22 and the current limiting coil 7.

The operation of the circuit configuration of the secondary side power receiving circuit will be described. A high frequency, for example, 10 kHz sinusoidal current is supplied to the induction line 1, and the magnetic flux generated in the induction line 1 generates a large electromotive force in the pickup coil 2 that resonates at the frequency of the induction line 1. The generated alternating current is rectified by the rectifying circuit 4, regulated to the reference voltage VE by the constant voltage control circuit 5 ', and supplied to the load 6.

Then, the load 6 decreases and the output voltage VDC
Rises and the output voltage VDC exceeds the reference voltage VE,
The output adjusting transistor 10 is turned on by the output signal of the comparator 9. At the same time, the timer 22 is started by the output signal of the comparator 9, and when the output signal of the timer 22 is turned on after a predetermined time (the set time of the timer 22), the second
The transistor 21 is turned on and the output adjustment transistor 10 is turned off.

With the above operation, the output adjusting transistor
When 10 is on, the output voltage VDC is lowered,
The output voltage VDC is maintained at the reference voltage VE, and the electric charge stored in the capacitor 3 is stored in the current limiting coil 7 to turn on the second transistor 21 and turn off the output adjusting transistor 10 to generate a current. The energy stored in the limiting coil 7 is output to the load 6 and is effectively used, so that the loss can be reduced.

Further, since the current does not always flow through the current limiting coil 7, the current capacity of the current limiting coil 7 can be reduced. In this way, it is possible to reduce the loss that has conventionally occurred when the output voltage VDC is maintained at the reference voltage VE, and it is possible to achieve energy saving as equipment. (Second Embodiment) FIG. 2 is a circuit configuration diagram of a secondary side power receiving circuit of a contactless power feeding facility according to a second embodiment of the present invention.

In the secondary side power receiving circuit of the second embodiment, instead of the second transistor 21 of the first embodiment, a secondary side power receiving circuit is provided between one input end of the rectifying circuit 4 and one output end of the rectifying circuit 4. Three
The transistor 21A is connected, and a fourth transistor is connected between the other input terminal of the rectifier circuit 4 and the one output terminal of the rectifier circuit 4.
21B is connected.

That is, the rectifier circuit 4 is composed of first and second diodes 4A and 4B having anodes connected thereto, a third diode 4C having its anode connected to the cathode of the first diode 4A, and a second diode 4B. The anode is connected to the cathode, and the cathode is composed of the fourth diode 4D to which the cathode of the third diode 4C is connected, and the third transistor 21A and the fourth diode 4A are provided at both ends of the first diode 4A and the second diode 4B, respectively. Transistor
21B is connected, and the current limiting coil 7 is interposed between the cathode of the third diode 4C of the rectifying circuit 4 and the transistor 10.

The output signal of the timer 22 turns on the third transistor 21A and the fourth transistor 21B. The operation and effect of the second embodiment are the same as those of the first embodiment.
Is the same as. Instead of the second transistor 21 of the first embodiment, a third transistor 21A and a fourth transistor 21
B works. (Embodiment 3) FIG. 3 is a circuit configuration diagram of a secondary side power receiving circuit of a contactless power feeding facility according to Embodiment 3 of the present invention.

In the secondary side power receiving circuit of the third embodiment, the second coil 31 is connected between the output limiting coil 7 and the output adjusting transistor 10 in the first embodiment, and the output limiting coil 7 and the output limiting coil 7 are connected to each other. The connection point of the second coil 31 is connected to the anode of the second diode 32, and the cathode of the second diode 32 is connected to the cathode of the (first) diode 11 (the output terminal of the constant voltage control circuit 5 ″). The second coil 31 is connected to the anode of the first diode 11.

The operation of the circuit configuration of the secondary side power receiving circuit will be described. A high frequency, for example, 10 kHz sinusoidal current is supplied to the induction line 1, and the magnetic flux generated in the induction line 1 generates a large electromotive force in the pickup coil 2 that resonates at the frequency of the induction line 1. The generated alternating current is rectified by the rectifying circuit 4, regulated to the reference voltage VE by the constant voltage control circuit 5 ″, and supplied to the load 6.

Then, the load 6 decreases and the output voltage VDC
Rises and the output voltage VDC exceeds the reference voltage VE,
The output adjusting transistor 10 is turned on by the output signal of the comparator 9. At the same time, the timer 22 is started by the output signal of the comparator 9, and when the output signal of the timer 22 is turned on after a predetermined time, the second transistor 21 is turned on and the output adjusting transistor 10 is turned off.

With the above operation, the output adjusting transistor
When 10 is turned on, a part of the electric charge accumulated in the capacitor 3 is accumulated in the second coil 31, the output voltage VDC is lowered, and the output voltage VDC is maintained at the reference voltage VE. When the second transistor 21 is turned on and the output adjustment transistor 10 is turned off, the energy stored in the second coil 31 is output to the load 6 and is effectively used, so that the loss can be reduced. .

Further, since the current does not always flow through the current limiting coil 7, the current capacity of the current limiting coil 7 can be reduced. Further, by providing the second coil 31, it is possible to reduce the current flowing through the transistor 10 when the output adjusting transistor 10 is turned on, and to reduce the current capacity of the transistor 10.

As described above, it is possible to reduce the loss that has been conventionally generated when the output voltage VDC is maintained at the reference voltage VE, and it is possible to achieve energy saving as equipment. In the third embodiment, instead of the second transistor 21,
The third transistor 21A and the fourth transistor 21B of the second embodiment may be provided.

[0028]

As described above, according to the present invention, it is possible to reduce the loss that has been conventionally generated when the constant voltage control circuit maintains the output voltage at the reference voltage, and it is possible to achieve energy saving as equipment. In addition, the current capacity of the current limiting coil can be reduced by eliminating the constant flow of current through the current limiting coil.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram of a secondary side power receiving circuit of a contactless power feeding facility according to a first embodiment of the present invention.

FIG. 2 is a circuit configuration diagram of a secondary side power receiving circuit of a contactless power feeding facility according to Embodiment 2 of the present invention.

FIG. 3 is a circuit configuration diagram of a secondary side power receiving circuit of a contactless power feeding facility according to a third embodiment of the present invention.

FIG. 4 is a circuit configuration diagram of a secondary side power receiving circuit of a conventional contactless power feeding facility.

[Explanation of symbols]

1 induction line 2 coils 3 Capacitor that forms a resonance circuit with the coil 4 Rectifier circuit 5 ', 5 "constant voltage control circuit 6 load 7 Current limiting coil 9 comparator 10 Output adjustment transistor (first transistor) 21 Second transistor 21A 3rd transistor 21B 4th transistor 22 timer 23 AND circuit 31 Second coil 32 diodes

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-5-336606 (JP, A) JP-A-9-308098 (JP, A) JP-A-7-115774 (JP, A) JP-A-60- 176465 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H02M 3/28 H01F 38/14 H02J 1/00 H02J 17/00

Claims (3)

(57) [Claims] 1. A coil is provided so as to face a primary-side induction line through which a high-frequency current flows, and a capacitor that forms a resonance circuit that resonates at the frequency of the induction line together with the coil is connected to the coil. A constant voltage control circuit for controlling an output voltage to a reference voltage is connected to the rectifier circuit, and the constant voltage control circuit is a secondary side power receiving circuit for supplying power to a load from the constant voltage control circuit. The constant voltage control circuit includes a first transistor for output adjustment that is turned on when the output voltage exceeds a reference voltage, a second transistor is connected between the output terminals of the rectifier circuit, and the first transistor and the first transistor are connected to each other. A current limiting coil is interposed between the two transistors to keep the output voltage of the constant voltage control circuit constant, so that when the first transistor is turned on, a predetermined time after that,
The second transistor is turned on and the first transistor is turned off, and the current limiting coil is always turned on.
Secondary side power receiving circuit of non-contact power feeding facility characterized by not passing current . 2. A coil is provided so as to face a primary-side induction line through which a high-frequency current flows, and a capacitor that forms a resonance circuit that resonates at the frequency of the induction line together with the coil is connected to the coil and the rectifier circuit is connected to this capacitor. A constant voltage control circuit for controlling an output voltage to a reference voltage is connected to the rectifier circuit, and the constant voltage control circuit is a secondary side power receiving circuit for supplying power to a load from the constant voltage control circuit. The constant voltage control circuit includes an output adjusting first transistor that is turned on when the output voltage exceeds a reference voltage, and a third transistor is provided between one input terminal of the rectifying circuit and one output terminal of the rectifying circuit. A fourth transistor is connected between the other input end of the rectifier circuit and the one output end of the rectifier circuit, and a current limiting coil is interposed between the rectifier circuit and the first transistor, For setting the output voltage of the voltage control circuit to a constant, when the first transistor is turned on, after the predetermined time period,
A configuration in which the third transistor and the fourth transistor are turned on and the first transistor is turned off ,
Secondary side power receiving circuit of the contactless power feeding apparatus characterized that it will not flow at all times current to the current limiting coil. 3. A second coil is interposed between the current limiting coil and the first transistor, and a connection point between the current limiting coil and the second coil is connected to an output end of a constant voltage control circuit. The secondary side power receiving circuit of the contactless power feeding equipment according to claim 1 or 2.