JP2011078266A - Noncontact power supply equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide noncontact power supply equipment that controls an output voltage of receiving-side equipment and controls the output voltage with high accuracy even the voltage supplied from a power supply unit is unstable. <P>SOLUTION: The noncontact power supply equipment includes: an insulating transformer for dividing a power supply side core and a receiving-side core and including an auxiliary winding in the power supply side core; a high-frequency driver circuit supplying a power-supply side coil wound on the power-supply side core with a high-frequency power; a mechanical recognizer to be mounted on the power-supply side core and recognizing information on the receiving side mechanically, and an auxiliary-winding voltage detector detecting the output voltage of the auxiliary winding. The noncontact power supply equipment includes a controller controlling an output from the high-frequency driver circuit by the detecting output of the auxiliary-winding voltage detector, and the recognizing information of the mechanical recognizer. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a non-contact power feeding device having an auxiliary winding in a power feeding side core.

In recent years, distributed power supply devices such as solar cells have begun to spread. However, at present, the DC power generated by the distributed power supply device is converted into AC, and equipment that consumes the AC power is converted into DC again and used. Thus, every time DC-AC conversion and AC-DC conversion are performed, a loss corresponding to the conversion efficiency occurs. In view of this, there has been a proposal for reducing power conversion loss by transmitting DC power as it is and using it in equipment without converting the DC power generated by the distributed power source into AC.
However, in the case of DC power transmission, the issue is the safety of the outlet. AC power is a sine wave with a constant frequency, and there are periodic moments when the voltage and current are zero, so the safety of plugging in and out is high. However, it is known that DC power has constant voltage and current, and there is no moment when it becomes zero, so that problems such as arcing occur when an outlet is connected or disconnected.

As a technique for solving such a problem, Patent Document 1 exists. Patent Document 1 makes it possible to separate the power supply side and the power reception side of an insulation transformer, configure the power supply side portion of the insulation transformer as an outlet body, and use the power reception side of the insulation transformer as an outlet cap so that it can be safely attached and detached even during direct current energization. Provide a convenient outlet. There are also many inventions similar to the present invention, and a safe outlet can be provided even with direct current. (Hereafter, this technology is referred to as “non-contact outlet technology”)
In such a non-contact outlet technology, since the power supply side and the power reception side of the insulation transformer can be separated, dust or the like may adhere to the separation surface. When dust or the like adheres to the separation surface on the power feeding side and power receiving side of the insulation transformer, the output voltage on the power receiving side is detected and feedback control is performed to control the drive circuit so that the output voltage matches the target value. High-precision communication may be hindered.

In order to solve the above problem, there are the following three patent documents as inventions for stabilizing the output voltage without performing feedback control.
Patent Document 2 assumes what kind of device is connected to the power receiving side, and when the device is connected to the power receiving side, by outputting a device-specific ID authentication signal, what kind of device is on the power feeding side Is connected, and the drive circuit operates at a predetermined duty ratio accordingly (no control).
Patent Document 3 is for stabilizing the output voltage of a power receiving device without each device performing communication such as ID authentication. In Patent Document 3, the duty ratio of the driving circuit on the power feeding side is not controlled by the feedback signal from the power receiving side, but the duty ratio of the driving circuit is fixed (no control). In this configuration, there is a problem that the output voltage decreases as the load current increases. However, by matching the inductance component in the power transmission path with the capacitance component, the impedance component in the power transmission path is reduced, and the power receiving side voltage is reduced. It becomes possible to keep it approximately constant.
In Patent Literature 4, the power supply side and the power receiving side perform output voltage stabilization without performing communication. An auxiliary winding is provided in the power supply side insulating transformer core, and the output of the power receiving side device is output from the output voltage information of the auxiliary winding. The voltage is estimated and controlled. By controlling in this way, the output voltage of the power receiving side device can be stabilized without requiring communication with the power receiving side.

JP-A-3-212134 JP 2008-206233 A JP 2001-119930 A US Pat. No. 6,972,969

  For example, consider the case where each household outlet is replaced with contactless power supply. Since the power supply side socket is installed on the wall side of the house and the power reception side plug is installed on the electrical equipment, the power supply side and the power reception side are manufactured. Different cases are assumed. Therefore, in order to establish communication on the power feeding side and the power receiving side, both standards must be unified. However, since the standards of both are not unified in practice, it is not preferable that the power feeding side and the power receiving side communicate with each other, and it is difficult to use the technique of Patent Document 2. In Patent Document 2, after the ID authentication of the device is performed, the drive circuit operates at a predetermined duty ratio, and thus the duty ratio cannot be controlled in accordance with the load amount fluctuation on the device side. Therefore, since an operation such as reducing the duty ratio cannot be performed at a light load, there is a problem that power transmission efficiency is deteriorated in that scene. In addition, when performing device ID authentication, there are many cases in which the device side does not have a power supply (electric power) in the initial stage, and how the device side ID authentication information is transmitted to the power supply side first when the outlet is connected. I have to solve it. Further, since duty ratio control is not performed, when the DC power supply voltage fluctuates, the output voltage of the device fluctuates due to the influence.

With respect to Patent Document 3, when the socket and the plug are attached, the inductance component of the power transmission path changes due to a slight deviation, so that it is difficult to perform load matching completely. In addition, it is impossible to completely remove the electrical resistance of the path, and in any case, a decrease in output voltage due to an increase in load current is inevitable. Further, since the drive circuit operates at a predetermined duty ratio, the duty ratio cannot be controlled in accordance with the load amount fluctuation on the device side. Therefore, since an operation such as reducing the duty ratio at a light load cannot be performed, there is a problem that power transmission efficiency deteriorates in that scene. Further, since duty ratio control is not performed, when the DC power supply voltage fluctuates, the output voltage of the device fluctuates due to the influence.
Patent Document 4 is a control method on the condition that the output voltage command value of the power receiving device is recognized in advance, and there is a possibility that a plurality of types may be connected to the power receiving device. When the target voltage is changed by the device, it is impossible to control the output voltage of the power receiving device.

  In view of the above problems, an object of the present invention is to provide a non-contact power feeding device that can perform output voltage control of a power receiving device. Thereby, the output voltage can be controlled with high accuracy. Further, the output voltage can be controlled with high accuracy even if the supply voltage of the power feeding unit is unstable. It is another object of the present invention to provide a non-contact power feeding device that can be recognized even when there is no power receiving side. As a result, when the power receiving side does not exist, the operation of the high-frequency driving circuit is completely stopped to reduce power consumption.

  The non-contact power feeding device of the present invention solves the above-described problems, and therefore, an insulating transformer that can divide a power feeding side core and a power receiving side core and has an auxiliary winding in the power feeding side core; A high-frequency driving circuit for supplying high-frequency power to a power-feeding coil wound around the power-feeding core, a mechanism recognition unit that is provided in the power-feeding core and mechanically recognizes information on the power-receiving side, and the auxiliary winding An auxiliary winding voltage detection unit that detects an output voltage, a detection output of the auxiliary winding voltage detection unit, and a control unit that performs output control of the high-frequency drive circuit based on recognition information of the mechanism recognition unit, To do.

The insulating transformer is configured such that the power feeding side core wound with the power feeding side coil and the power receiving side core wound with the power receiving side coil are separable, and the power feeding side core and the power receiving side core are electromagnetically coupled to each other. AC power is transmitted from the coil to the power receiving coil.
The auxiliary winding is wound around the power feeding side core and detects electromagnetic coupling between the power feeding side core and the power receiving side core. The mechanism recognizing unit includes a mechanism unit having a different shape corresponding to the operating voltage of the power receiving device. The mechanism recognizing unit recognizes the shape of the mechanism unit when the power feeding side core and the power receiving side core are contacted so as to be electromagnetically coupled. Information on the load connected to the power receiving coil is acquired by the mechanism recognition unit, and the control unit performs output control of the high-frequency drive circuit based on the detection output of the auxiliary winding and the information of the mechanism recognition unit. For example, the control unit controls the output voltage by performing duty ratio control on the high frequency drive circuit based on the detection output of the auxiliary winding and the recognition information of the mechanism recognition unit.

  According to the present invention, it is possible to control the output voltage of the power receiving side device without performing communication with the power receiving side device in a non-contact outlet where any power receiving side device may be connected. Control becomes possible. In addition, it is possible to control the output voltage with high accuracy even when the supply voltage of the DC power feeding unit is unstable. Further, in the present invention, it is possible to recognize the case where there is no power receiving side, and in that case, power consumption can be reduced by completely stopping the operation of the high-frequency driving circuit.

1 shows a circuit diagram of an embodiment of the present invention. The circuit diagram of the plug used for this invention is shown. Fig. 3 shows a circuit diagram of another plug used in the present invention.

FIG. 1 shows a circuit diagram of an embodiment of the present invention.
The DC power supply unit 1 is a DC power supply having an output voltage of 400V, for example. Such a DC power supply unit 1 is constituted by a solar power generation device. In particular, a thin film solar cell is optimal as a 400V DC power source. Such a DC power supply is an example, and for example, a fuel cell, a wind power generator, a power generator, or other DC power supply can be used.

The output power of the DC power supply unit 1 is supplied to the DC load 3 through the non-contact power supply unit 2.
The non-contact power feeding unit 2 includes a socket 21 and a plug 31. The socket 21 and the plug 31 are separable. The socket 21 is installed on a wall surface of a building, for example, and the plug 31 is an electric device or an electric device. Provided at the end of the cord extended from
The socket 21 includes a power supply side insulating transformer core 22, and a power supply side coil 23 and an auxiliary winding 24 wound around the power supply side insulating transformer core 22. The power feeding side coil 23 is wound around the central portion of the U-shaped power feeding side insulating transformer core 22. The auxiliary winding 24 is wound around one core tip, detects the voltage of the tertiary auxiliary winding, and transmits voltage information to the control unit 41 via the auxiliary winding voltage detection unit 26. The number of windings of the power supply side coil 23 is 30 turns, and the auxiliary winding 24 is 3 turns. The socket 21 provided with these parts is integrated by a resin mold.
The outer surface of the socket 21 is formed in a flat shape so that the socket 21 is flush with the plane of the wall 4.

  The output terminals 11 and 12 of the DC power supply unit 1 are connected to the AC-DC conversion unit 5. The AC-DC converter 5 includes a switching element 51 such as a switching transistor and a controller 52, and the output of the AC-DC converter 5 is supplied to the power supply side coil 23. The control unit 52 controls the switch element 51 to operate at a frequency higher than the commercial AC power supply frequency. For example, the switching operation is performed in the region of several kHz to 150 kHz.

  The auxiliary winding 24 detects the voltage of the tertiary auxiliary winding and transmits voltage information to the control unit 52 via the auxiliary winding voltage detection unit 26. The controller 52 controls the switching operation of the switch element 51 based on the voltage detected by the auxiliary winding 24. This switching operation control will be described later.

  The socket 21 includes a plug-side mechanism recognition unit 61 including a plurality of mechanism switches (three) a, b, and c extending in the depth direction from the wall surface. Here, the description will be made assuming that three mechanism switches are provided. However, the number of mechanism switches may be two, or may be three or more. The plug-side mechanism recognizing unit 61 is configured such that one to three switches are mechanically turned on by the shape of a convex portion formed integrally with the plug when the plug is connected. The number of turning on the mechanism switch varies depending on the length of the convex portion corresponding to the target voltage of the DC load. Therefore, the number of mechanism switches turned on holds the target voltage information of the DC load. When one switch is turned on, for example, the target voltage is 20 V, and when two switches are turned on, for example, the target voltage is turned on. When the voltage is 50 V and three switches are turned on, the target voltage is 100 V, for example.

For example, there are two types of plug-side loads: a liquid crystal television that operates at 20V DC voltage and an air conditioner that operates at 100V DC voltage.
FIG. 2 shows a plug 31a when the load is a liquid crystal television, and has a convex portion 32a having a length for turning on one switch a of the plug-side mechanism recognition unit 61 when the plug is connected. The number of windings of the power receiving side coil 34a wound around the insulating transformer core 33a of the plug 31a is 6 turns. The convex portion 32a, the insulating transformer core 33a, and the power receiving side coil 34a are integrated by a resin mold 35a.
The output of the power receiving coil 34a is supplied to the liquid crystal television 3a through the rectifier circuit 35a and the smoothing circuit 36a. The rectifier circuit 35a is configured by one diode, for example. The smoothing circuit 36a is composed of a capacitor.

FIG. 3 shows a plug 31b when the load is an air conditioner, and has a convex portion 32b having a length for turning on three switches a, b, c of the plug-side mechanism recognition unit 61 when the plug is connected. The number of windings of the power receiving side coil 34b wound around the insulating transformer core 33b of the plug 31b is 18 turns. The output of the power receiving coil 34b is supplied to the air conditioner 3b through the rectifier circuit 35a and the smoothing circuit 36a.
In this embodiment, since the duty control of the switching element is performed, the winding ratio of the primary side coil and the secondary side coil is not equal to the voltage ratio of the DC power supply unit and the DC load.

Next, the flyback converter will be described. The flyback converter is formed by a power feeding side and a power receiving side, and operates as a step-up / step-down converter. That is, when the switch element 51 is on, energy is accumulated in the transformer core unit 23 and the transformer core unit 33, and when the switch element 51 is off, energy accumulated in the transformer core unit 23 and the transformer core unit 33 is released to the DC load. Although the flyback converter is used in this embodiment, other types of converters can be used.
Here, the non-contact power feeding apparatus of the present invention compares the DC load voltage V3 detected by the auxiliary winding 24 with the DC load voltage target value recognized by the convex shape of the plug by the control unit 52, and both Are controlled so as to coincide with each other.

Next, DC load voltage detection by the auxiliary winding 24 will be described. The operating voltage of the DC load 3 acquired by the plug-side mechanism recognition unit 61 is V2, the total voltage drop due to the wiring resistance between the plug 31 and the DC load 3 and the voltage drop due to the rectifier circuit 36 and the smoothing circuit 37 is ΔV, auxiliary When the detection voltage of the winding 24 is V3, the number of windings of the power receiving side coil 34 wound around the plug side insulating transformer core 33 is N2, and the number of windings of the primary side auxiliary winding 24 is N3, the switch element 51 is turned off. The detection voltage V3 at the time (while the energy accumulated in the transformer core part is transmitted to the load side) is obtained by the following equation (1).
V3 = N3 / N2 × (V2 + ΔV) (1)
In equation (1), N3 and N2 are known, and ΔV is known from the design on the plug side, so that the operating voltage V2 of the DC load 3 is derived by detecting the detection voltage V3 by the control unit 52. It becomes possible. Since the detection voltage V3 must be detected when the switch element 51 is turned off (while the energy accumulated in the transformer core part is transmitted to the load side), the control unit 52 detects when the switch element 51 is turned off. Control must be made to detect voltage V3.

Next, the operation of the embodiment of the present invention will be described.
When the plug 31 is not connected, no switch of the plug-side mechanism recognition unit 61 is turned on, so that the switch element 51 is always off. For this reason, the operation of the switch element 51 can be completely stopped, and standby power can be reduced.

  Next, a case where the plug 31a is connected will be described. When the plug 31a is connected, one switch a of the plug-side mechanism recognition unit 61 is turned on. Thereby, the control unit 52 recognizes that a device (liquid crystal television) to be supplied with power at 20 V is connected to the plug side (recognition of the DC load voltage target value). Here, if ΔV = 2, N3 = 3, N2 = 6, and the target value of V2 is 20. Therefore, V3 can be obtained as 11V by the equation (1). Therefore, the control unit 52 controls the duty ratio of the switch element 51 so that V3 derived every time when the switch element 51 is off (while the energy accumulated in the transformer core part is transmitted to the load side) becomes 11V. To do.

  Next, a case where the plug 31b is connected will be described. When the plug 31b is connected, the three switches a, b, and c of the plug-side mechanism recognition unit 61 are turned on. Thereby, the control part 52 recognizes that the apparatus (air conditioner) which should be supplied with power at 100V is connected to the plug side (recognition of DC load voltage target value). Here, if ΔV = 2, N3 = 3, N2 = 18, and the target value of V2 is 100. Therefore, V3 can be determined to be 17V by the equation (1). Therefore, the control unit 52 controls the duty ratio of the switch element 51 so that V3 derived every time the switch element 51 is turned off (while the energy accumulated in the transformer core part is transmitted to the load side) becomes 17V. To do.

In the embodiment described above, the duty ratio control of the switching element is performed so that the detection voltage of the auxiliary winding becomes a predetermined voltage. However, the duty ratio is controlled using the output voltage of the power supply side coil without using the auxiliary winding. Ratio control may be performed. Even when the duty ratio is controlled by using the output voltage of the power supply coil, the DC load voltage can be measured in the same manner according to the equation (1) when the switch is off. By doing so, it is possible to eliminate the auxiliary winding, but when the number of turns of the power supply side coil is 30 turns as in the above embodiment, if the auxiliary winding is 3 turns, the detection voltage is increased 10 times. Become. For this reason, it is necessary to increase the withstand voltage of the control unit, or to step down the voltage with a DC / DC converter or the like before inputting the detection voltage to the control unit.
In order to eliminate such a problem, when the winding of the power supply side coil 23 is 30 turns, the voltage is extracted by the tap method only for any three consecutive turns, and the voltage is used as in the above embodiment. Duty ratio control may be realized.

  In the present embodiment, the voltage of the DC power supply unit 1 is set to 400 V. However, even if the output voltage of the DC power supply unit 1 varies greatly, such as 300 to 400 V, the control unit 52 controls the duty ratio of the switch element 51. Therefore, stable voltage supply to the DC load is possible. Thus, according to the present invention, stable voltage supply to the DC load is possible even if the output voltage of the DC power supply unit 1 fluctuates greatly.

DESCRIPTION OF SYMBOLS 1 DC power supply part 2 Non-contact power supply part 3 Load 5 AC-DC conversion part 21 Socket 22 Power supply side core 23 Power supply side coil 24 Auxiliary winding 31 Plug 32 Convex part 33 Power reception side core 34 Power reception side coil 36 Rectification circuit 37 Smoothing circuit 51 Switch element 52 Control unit 61 Plug side mechanism recognition unit

Claims (6)

An insulating transformer in which the power feeding core and the power receiving core can be divided, and the power feeding core has an auxiliary winding;
A high frequency drive circuit for supplying high frequency power to a power supply coil wound around the power supply core;
A mechanism recognition unit that is provided in the power supply side core and mechanically recognizes information on the power receiving side;
An auxiliary winding voltage detector for detecting the output voltage of the auxiliary winding;
A non-contact power feeding apparatus comprising: a detection output of the auxiliary winding voltage detection unit; and a control unit that performs output control of the high-frequency drive circuit based on recognition information of the mechanism recognition unit.   The contactless power supply device according to claim 1, wherein the mechanism recognition unit acquires target value information of a power receiving side output voltage.   The non-contact power feeding apparatus according to claim 1, wherein the mechanism recognition unit recognizes a depth length of the power receiving side plug. The number of windings of the coil wound around the power receiving side core is N2, the number of windings of the auxiliary winding is N3, the total voltage drop including the wiring resistance between the power receiving side coil and the load is ΔV, The detection voltage V3 of the auxiliary winding is obtained by the following equation when the load operating voltage is V2, and the control unit controls the switch element to detect the detection voltage V3. Non-contact power feeding device.
V3 = N3 / N2 × (V2 + ΔV) (1)   The non-contact power feeding apparatus according to claim 4, wherein the control unit performs control so that the detection voltage V <b> 3 is detected when the switch element is turned off.   The contactless power feeding device according to claim 4, wherein a detection voltage is obtained by extracting a voltage from an arbitrary partial winding of the power feeding side coil by a tap method.

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