JPH11252912A - Secondary side power receiving circuit of noncontact power feeding installation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a secondary side power receiving circuit capable of reducing energy loss. SOLUTION: This power receiving circuit is provided with a coil 7 for current limiting, whose one terminal is connected with the positive output end of a rectifier circuit 4, a transistor 10 for output adjustment which is connected between the other terminal of the coil 7 and the negative output end of the rectifier circuit 4, and is turned on when an output voltage exceeds a reference voltage, and a second transistor 21 connected between the positive output end of the rectifier circuit 4 and the negative output end. In order to make an output voltage VDC of a constant voltage control circuit 5' constant, when the transistor 10 for output adjustment is turned on, the second transistor 21 is turned on after a specified time, and the transistor 10 is turned off. With this constitution, energy loss which has been generated in conventional systems when the constant voltage control circuit 5' maintains an output voltage to be constant can be reduced, and energy saving is achieved as facilities.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art An example of a secondary side power receiving circuit of a conventional contactless power feeding facility will be described with reference to FIG. The secondary-side power receiving circuit is provided with a coil 2 opposed to a primary-side induction line 1 through which a high-frequency current flows, and a capacitor 3 that forms a resonance circuit that resonates with the coil at the frequency of the induction line 1 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 for comparing the output voltage VDC with the reference voltage VE of the voltage generator 8;
It is composed of an output adjusting transistor 10 which is turned on by the comparator 9 when exceeding E, a diode 11 and a capacitor 12 forming a filter. The reference voltage VE is set to a high voltage on the assumption that power is supplied to the full load 6. The power of the load 6 is the operating voltage VD
When C, that is, the reference voltage VE is increased, it becomes larger.

With the configuration of the constant voltage control circuit 5, when the load 6 decreases, the output voltage VDC increases, and the output voltage VDC increases.
Exceeds the reference voltage VE, the transistor 9 is turned on by the comparator 9, and the output voltage VDC is reduced.
The output voltage VDC is maintained at the reference voltage VE.

[0005]

However, in such a conventional secondary power receiving circuit of the non-contact power feeding equipment, when the transistor 10 is turned on, the electric charge (the resonant coil 2 And the energy of capacitor 3)
However, there is a problem that all of the power is consumed by the coil 7 and the transistor 10 and a large loss occurs. 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 increases, and the energy loss increases.

Accordingly, an object of the present invention is to provide a secondary-side power receiving circuit of a non-contact power supply equipment capable of reducing energy loss.

[0007]

In order to achieve the above-mentioned object, a secondary power receiving circuit of the non-contact power feeding equipment according to the first aspect of the present invention comprises a coil opposed to a primary induction line through which a high-frequency current flows. Connected to this coil, a capacitor that forms a resonance circuit that resonates with the coil at the frequency of the induction line,
Connect a rectifier circuit to this capacitor,
A constant voltage control circuit that controls an output voltage to a reference voltage is connected, and the secondary voltage receiving circuit of the contactless power supply equipment that supplies power to the load from the constant voltage control circuit, wherein the constant voltage control circuit has an output voltage of A first transistor for output adjustment that is turned on when a reference voltage is exceeded; a second transistor connected between output terminals of the rectifier circuit; and a current limiting coil between the first transistor and the second transistor. Interposed,
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,
The second transistor is turned on and the first transistor is turned off.

With the above structure, 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 when the first transistor is turned on. The electric charge accumulated in the current limiting coil is output to the load, so that the loss can be reduced.

In the secondary power receiving circuit of the non-contact power supply equipment according to the second invention, a coil is provided opposite to the primary induction line through which a high-frequency current flows, and the coil resonates with the coil at the frequency of the induction line. A capacitor that forms a resonance circuit is connected, a rectifier circuit is connected to the capacitor, a constant voltage control circuit that controls the output voltage to a reference voltage is connected to the rectifier circuit, and power is supplied to the load from the constant voltage control circuit. A secondary-side power receiving circuit of a non-contact power supply equipment, wherein the constant voltage control circuit includes an output adjustment first transistor that is turned on when an output voltage exceeds a reference voltage, and one input of the rectifier circuit. A third transistor is connected between the first rectifier circuit and one output terminal of the rectifier circuit, a fourth transistor is connected between the other input terminal of the rectifier circuit and the one output terminal of the rectifier circuit, and the rectifier circuit is connected to the first transistor. Tiger The coil current limitation interposed between the register, to the output voltage of the constant voltage control circuit to a constant,
When the first transistor is turned on, the third transistor and the fourth transistor are turned on and the first transistor is turned off after a predetermined time.

With the above configuration, the electric charge stored in the capacitor is stored in the current limiting coil when the first transistor is turned on, and the third transistor and the fourth transistor are turned on.
When the transistor is turned on and the first transistor is turned off, the electric charge accumulated in the current limiting coil is output to the load, so that the loss can be reduced.

The secondary power receiving circuit of the contactless power supply equipment according to the third invention is the secondary power receiving circuit of the contactless power supply equipment according to the first invention or the second invention, wherein the current limiting coil and the first power receiving circuit are connected to each other. 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 a constant voltage control circuit.

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

[0013]

Embodiments of the present invention will be described below with reference to the drawings. The same components as those of the conventional example shown in FIG. 4 are denoted by the same reference numerals, and description thereof is omitted. (Embodiment 1) FIG. 1 is a circuit configuration diagram of a secondary-side power receiving circuit of a non-contact power feeding facility according to Embodiment 1 of the present invention.

The secondary power receiving circuit according to the first embodiment has a second transistor 21 connected between a positive output terminal and a negative output terminal of the rectifier circuit 4, and a constant voltage control circuit 5 'including a comparator. There is provided a timer 22 which starts counting when the output signal of No. 9 is turned on. When the count value reaches a preset count value (set time), the timer 22 turns on the output signal, and turns on the second transistor 21 by the ON output signal. An AND circuit 23 is provided in the constant voltage control circuit 5 ', and when the output signal of the comparator 9 is turned on and the output signal of the timer 22 is turned off, the output adjusting transistor 10 is turned on. I have. The set time of the timer 22 is a time required for the voltage of the capacitor 3 to sufficiently fall to a predetermined voltage, and is set by the characteristics of the capacitor 22 and the current limiting coil 7.

The operation of the above-mentioned secondary-side power receiving circuit will be described. A high frequency, for example, a 10 kHz sine wave current is supplied to the induction line 1, and a 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 AC current thus obtained is rectified by a rectifier circuit 4, regulated to a reference voltage VE by a constant voltage control circuit 5 ′, and supplied to a 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 adjustment 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 (set time of the timer 22), the second
The transistor 21 is turned on and the output adjusting transistor 10 is turned off.

By the above operation, the output adjusting transistor
When 10 is on, the output voltage VDC is lowered,
When the output voltage VDC is maintained at the reference voltage VE, the electric charge stored in the capacitor 3 is stored in the current limiting coil 7, and when the second transistor 21 is turned on and the output adjusting transistor 10 is turned off, 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.

Since current does not always flow through the current limiting coil 7, the current capacity of the current limiting coil 7 can be reduced. As described above, the loss that occurs when the output voltage VDC is maintained at the reference voltage VE, which has conventionally occurred, can be reduced, and energy can be saved as equipment. (Embodiment 2) FIG. 2 is a circuit configuration diagram of a secondary-side power receiving circuit of a non-contact power supply equipment according to Embodiment 2 of the present invention.

The secondary-side power receiving circuit according to the second embodiment is different from the first embodiment in that the second transistor 21 is replaced by a second power receiving circuit between one input terminal of the rectifier circuit 4 and one output terminal of the rectifier circuit 4. 3
A transistor 21A 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 the first and second diodes 4A and 4B each having an anode connected thereto, the third diode 4C having its anode connected to the cathode of the first diode 4A, and the second diode 4B. The anode is connected to the cathode, and the cathode is constituted by a fourth diode 4D to which the cathode of the third diode 4C is connected. A third transistor 21A and a fourth transistor 4D are provided at both ends of the first diode 4A and the second diode 4B, respectively. Transistor
21B is connected, and a current limiting coil 7 is interposed between the cathode of the third diode 4C of the rectifier circuit 4 and the transistor 10.

The third transistor 21A and the fourth transistor 21B are turned on by the output signal of the timer 22. 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 operates. (Embodiment 3) FIG. 3 is a circuit configuration diagram of a secondary-side power receiving circuit of a non-contact power feeding facility according to Embodiment 3 of the present invention.

The secondary-side power receiving circuit according to the third embodiment includes a second coil 31 connected between the output limiting coil 7 and the output adjusting transistor 10 according to the first embodiment. 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 secondary power receiving circuit will be described. A high frequency, for example, a 10 kHz sine wave current is supplied to the induction line 1, and a 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 AC current thus obtained is rectified by a rectifier circuit 4, regulated to a reference voltage VE by a constant voltage control circuit 5 ″, and supplied to a 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 adjustment 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.

By the above operation, the output adjusting transistor
When 10 is turned on, a part of the electric charge stored in the capacitor 3 is stored 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 adjusting 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. .

Since 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, the current flowing through the transistor 10 when the output adjusting transistor 10 is turned on can be reduced, and the current capacity of the transistor 10 can be reduced.

As described above, the loss that occurs when the output voltage VDC is maintained at the reference voltage VE, which has conventionally occurred, can be reduced, and energy can be saved 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 occurs when the constant voltage control circuit maintains the output voltage at the reference voltage, and to achieve energy saving as equipment.

[Brief description of the drawings]

FIG. 1 is a circuit configuration diagram of a secondary-side power receiving circuit of a non-contact power feeding facility according to Embodiment 1 of the present invention.

FIG. 2 is a circuit configuration diagram of a secondary-side power receiving circuit of a wireless power supply system according to Embodiment 2 of the present invention.

FIG. 3 is a circuit configuration diagram of a secondary-side power receiving circuit of a non-contact power feeding facility according to Embodiment 3 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]

 DESCRIPTION OF SYMBOLS 1 Induction line 2 Coil 3 Capacitor which forms a resonance circuit with a 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 Third transistor 21B Fourth transistor 22 Timer 23 AND circuit 31 Second coil 32 Diode

Claims (3)

[Claims] A coil is provided opposite a primary induction line through which a high-frequency current flows, and a capacitor that forms a resonance circuit that resonates with the coil at the frequency of the induction line is connected to the coil, and a rectifier circuit is connected to the capacitor. Connected to the rectifier circuit, a constant-voltage control circuit for controlling the output voltage to the reference voltage, the secondary-side power receiving circuit of the non-contact power supply equipment for supplying power to the load from the constant voltage control circuit, The constant voltage control circuit includes an output adjustment first transistor that is turned on when an output voltage exceeds a reference voltage, a second transistor is connected between 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, and in order to keep the output voltage of the constant voltage control circuit constant, when the first transistor is turned on, after a predetermined time,
A secondary-side power receiving circuit for a non-contact power feeding facility, wherein the second transistor is turned on and the first transistor is turned off. 2. A coil is provided opposite to a primary-side induction line through which a high-frequency current flows, and a coil and a capacitor forming a resonance circuit that resonates with the frequency of the induction line are connected to the coil. Connected to the rectifier circuit, a constant-voltage control circuit for controlling the output voltage to the reference voltage, the secondary-side power receiving circuit of the non-contact power supply equipment for supplying power to the load from the constant voltage control circuit, The constant voltage control circuit includes a first transistor for output adjustment that is turned on when an output voltage exceeds a reference voltage, and includes a third transistor between one input terminal of the rectifier circuit and one output terminal of the rectifier circuit. Connecting a fourth transistor between the other input terminal of the rectifier circuit and the one output terminal of the rectifier circuit, interposing a current limiting coil 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 secondary-side power receiving circuit for wireless power feeding equipment, wherein the third transistor and the fourth transistor are turned on and the first transistor is turned off. 3. A method according to claim 2, wherein 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 terminal of the constant voltage control circuit. The secondary power receiving circuit of the contactless power supply equipment according to claim 1 or 2.