JP2013090514A - Non-contact power transmission device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-contact power transmission device, having good transmission efficiency with reduced manufacturing cost by simplifying a protection circuit to protect a communication circuit.SOLUTION: In a non-contact power transmission device 1 performing power transmission and communication in a contactless manner, a power transmission device 2 includes power transmission coil 5, power transmission unit 7, communication processing unit 8, control unit 9, semiconductor switch 4 and shared matching unit 6. Also, a power reception device 3 includes a power reception coil 15. The semiconductor switch 4 is connected in series to the communication processing unit 8, and the communication processing unit 8 and the power transmission unit 7 are connected in parallel. Further, the power transmission coil 5 is connected to the power transmission unit 7 and the semiconductor switch 4 through the shared matching unit 6, and the control unit 9 is connected to the power transmission unit 7 and the communication processing unit 8. The semiconductor switch 4 conducts at communication processing with the power reception device 3, and is switched off at power transmission, so as to switch over the communication processing unit 8 to the power transmission unit 7.

Description

  The present invention relates to a non-contact power transmission apparatus that performs non-contact power transmission and data communication using electromagnetic coupling or electromagnetic resonance.

  In recent years, with the miniaturization of electronic components, portable electronic devices typified by mobile phones and portable music players are becoming more and more popular due to the reduction in size and weight. Further, in recent years, portable electronic devices have been made multifunctional and high-speed processing, and accordingly, the amount of power required for the portable electronic devices has been increasing. However, general portable electronic devices are driven by electric power charged in a built-in secondary battery, and often have a configuration in which the secondary battery is charged every time the power of the secondary battery is insufficient.

  Recently, there is an increasing demand for a non-contact power transmission device using a non-contact power transmission technology that utilizes the principles of electromagnetic induction and magnetic resonance and enables power transmission without a metal contact. The non-contact power transmission technology does not require an electrical contact, so that it has no danger of an electric shock or a short circuit, and also has features such as no contact failure and excellent durability.

  The non-contact power transmission apparatus needs to communicate authentication information of the power receiving apparatus and control information such as a charging capacity between the power transmitting apparatus side and the power receiving apparatus side in order to prevent malfunction and the like and efficiently transmit power. For this reason, in general, information communication such as authentication information and control information is performed between the power transmission device and the power receiving device, and power transmission is performed after confirming whether the power receiving device is a compatible device on the power transmission device side. ing.

  As a conventional configuration for performing such processing, there is a non-contact power transmission device that performs power transmission processing and communication processing with one coil. However, in the case of a configuration in which the power transmission process and the communication process are performed with one coil, the power for charging is larger than that of the communication signal, so there is a possibility that the circuit for communication processing is destroyed by the charging power. there were.

  Conventionally, as a countermeasure, a protection circuit is interposed in the communication processing circuit in order to protect the communication processing circuit from the charging power. Thus, for example, there is a method disclosed in Patent Document 1 as a configuration in which a protection circuit for protecting a communication circuit from high power is interposed.

JP 2003-348837 A

  However, when the protection circuit for protecting the communication circuit is interposed as in the prior art, there is a problem that the circuit configuration becomes complicated and the manufacturing cost increases.

  Accordingly, an object of the present invention is to provide a non-contact power transmission device with good transmission efficiency, in which a protection circuit for protecting a communication circuit is simplified and manufacturing cost is reduced.

  In order to solve the above problems, a non-contact power transmission apparatus according to the present invention comprises a power transmission apparatus having a power transmission coil and a power reception apparatus having a power reception coil that is magnetically coupled to the power transmission coil. The power transmission device further includes a power transmission unit, a communication processing unit, a control unit, a semiconductor switch, and a shared matching unit, and the shared matching unit is connected to the power transmission unit, and the semiconductor switch One end of the semiconductor switch is connected between the shared matching unit and the power transmission unit, the other end of the semiconductor switch is connected to the communication processing unit, the power transmission coil via the shared matching unit and the power transmission unit and the power transmission unit The control unit is connected to a semiconductor switch, and the control unit is connected to the communication processing unit and the power transmission unit.

  The contactless power transmission apparatus according to the present invention is characterized in that the shared matching unit equalizes an input impedance of the shared matching unit and an output impedance of the power transmission unit and the communication processing unit.

  With the above configuration, a non-contact power transmission device with high transmission efficiency can be obtained with a simplified protection circuit for protecting a communication circuit and reduced manufacturing costs.

It is a block diagram which shows the structure of the non-contact electric power transmission apparatus by embodiment of this invention. It is a flowchart which shows operation | movement of the non-contact electric power transmission apparatus by embodiment of this invention. It is a state transition diagram which shows operation | movement of the electric power transmission part and communication processing part of the non-contact electric power transmission apparatus by embodiment of this invention. It is a circuit diagram which shows an example of the matching part of the power transmission apparatus by the Example of this invention.

  Hereinafter, embodiments of the present invention will be described in detail.

  FIG. 1 is a block diagram showing a configuration of a non-contact power transmission apparatus according to an embodiment of the present invention. As shown in FIG. 1, the non-contact power transmission device 1 according to this embodiment includes a power transmission device 2 and a power reception device 3. The power transmission device 2 includes a power transmission unit 7 that transmits power, a communication processing unit 8 that performs communication, a semiconductor switch 4 that switches between the power transmission unit 7 and the communication processing unit 8, a power transmission unit 7, and a communication processing unit 8. And a control unit 9 that controls the semiconductor switch 4, a shared matching unit 6, and a power transmission and reception coil 3 that transmits and receives communication signals to and from the power receiving device 3.

  Furthermore, the power transmission unit 7 includes a charging amplifier 10 that transmits charging power, and a charging matching unit 11 that performs impedance matching. The communication processing unit 8 includes a communication amplifier 12 that transmits a communication signal, A communication matching unit 13 that performs impedance matching and a receiving unit 14 that receives a communication signal returned from the power receiving device 3 are provided.

  In addition, the power receiving device 3 of the non-contact power transmission device according to the present embodiment receives power from the power transmission device 2 and receives and transmits a communication signal with the power transmission device 2, a secondary battery 17, and a power reception device. The charging unit 16 for charging the secondary battery 17 with the power thus generated and the communication unit 18 for controlling the communication signal are provided.

  The power transmission coil 5 is magnetically coupled to the power reception coil 15 to transmit power to the power reception device 3, and transmits and receives communication signals between the power transmission device 2 and the power reception device 3.

  Here, in general, a semiconductor switch may generate heat or be damaged when a large current is passed during conduction. Therefore, in order to prevent the semiconductor switch 4 from being heated or damaged due to a large current, it is desirable that the semiconductor switch 4 is connected in series to the communication processing unit 8 and connected in parallel to the power transmission unit 7.

  The shared matching unit 6 is configured by an impedance conversion circuit, lowers the impedance of the power transmission coil 5, and lowers the voltage applied to the semiconductor switch 4. As a result, the voltage at the input side of the shared matching unit 6, which is a connection part with the semiconductor switch 4, can be lowered from the output side of the shared matching part 6, which is a connection part with the power transmission coil 5.

  Here, generally, if a high voltage is applied in a state where the semiconductor switch is turned off, the semiconductor switch may be damaged. Therefore, the shared matching unit 6 is interposed between the semiconductor switch 4 and the power transmission coil 5 to lower the impedance of the power transmission coil 5. When the impedance of the power transmission coil 5 is lowered, the voltage applied to the semiconductor switch 4 is lowered, and the semiconductor switch 4 can be prevented from being damaged.

  The charging matching unit 11 includes a filter circuit such as impedance conversion, high-frequency noise removal, or direct current removal, and matches the impedance of the charging amplifier 10 and the impedance of the power transmission coil 5.

  The communication matching unit 13 includes a filter circuit or the like for impedance conversion, high-frequency noise removal, or direct current removal, and matches the impedance of the communication amplifier 12 and the impedance of the power transmission coil 5.

  Further, by interposing the common matching unit 6, the output impedance of the matching unit for charging 11 and the matching unit for communication 13 and the input impedance of the common matching unit 6 can be equivalent, and transmission loss of charging power and communication signal can be suppressed.

  In a configuration in which power transmission and transmission / reception of communication signals are performed using a common antenna, switching between the power transmission unit and communication processing unit can be performed by incorporating a single semiconductor switch as a protection circuit for protecting the communication circuit. Thus, the protection circuit can be simplified as compared with the prior art, and the manufacturing cost can be reduced.

  In the non-contact power transmission device of the present invention, a mechanical relay can be used instead of the semiconductor switch. Since the mechanical relay is a switch composed of mechanical contacts, the resistance at the time of conduction is very small, and it can be connected in series to the power transmission unit. However, it is desirable to have a semiconductor switch that has a high switching speed, has a long life because there is no contact wear, can suppress noise when the switch is turned on and off because of no contact, and is small, light, and excellent in mountability. The use of a semiconductor switch or a mechanical relay may be appropriately selected according to the purpose. The semiconductor switch preferably uses a field effect transistor or a photo relay.

  Here, although the antenna on the power receiving apparatus side has one antenna configuration in which charging and communication are performed using a common coil, two antenna configurations may be used as the charging antenna and the communication antenna.

  FIG. 2 is a flowchart showing the operation of the non-contact power transmission apparatus according to the embodiment of the present invention. The non-contact power transmission apparatus according to the present invention operates mainly by performing two processes of an identification information acquisition process and a power transmission process.

  FIG. 3 is a state transition diagram showing operations of the power transmission unit and the communication processing unit of the non-contact power transmission apparatus according to the embodiment of the present invention. FIG. 3 is a timing diagram illustrating an example of operations of a power transmission unit and a communication processing unit when the processing of the flowchart illustrated in FIG. 2 is performed.

  As shown in FIG. 2 and FIG. 3, the power transmission device 2 transmits an identification information inquiry signal of the power reception device 3 at a predetermined interval in order to confirm whether the power reception device 3 is placed within the power transmission range. ID information acquisition processing is performed. If there is no response to the identification information inquiry signal, the identification information inquiry signal is repeatedly transmitted after a certain period of time. When the response to the identification information inquiry signal is received, the power transmission device 2 proceeds to the power transmission process.

  Here, the identification information inquiry signal is output from the control unit 9 of the power transmission device 2, passes through the common matching unit 6 through the communication amplifier 12, the communication matching unit 13, and the semiconductor switch 4, and then passes from the power transmission coil 5 to the power receiving device 3. Sent. The power receiving device 3 that has received the identification information inquiry signal performs processing such as generating a response signal in the communication unit 18, and sends a communication signal indicating that power transmission can be started to the power transmitting device 2 via the power receiving coil 15. Send back. In the power transmission device 2, the communication signal from the power reception device 3 received by the power transmission coil 5 is transmitted to the control unit 9 via the common matching unit 6, the semiconductor switch 4, and the reception unit 14. At this time, the semiconductor switch 4 is in a conductive state.

  In the power transmission process, a charge capacity confirmation signal for confirming the charge capacity of the secondary battery 17 is transmitted to the power receiving device 3 in the same manner as the identification information inquiry signal. Thereafter, the power transmission device 2 acquires the charge capacity returned from the power reception device 3, determines whether the secondary battery 17 is fully charged, and transmits power for a predetermined time if insufficient. Then, the process of transmitting the charge capacity confirmation signal is repeated again.

  At this time, when it is determined that the charging capacity is fully charged, the power transmission device 2 skips the power transmission process and proceeds to the identification information acquisition process. When the secondary battery 17 is in a fully charged state, the power receiving device 3 may perform a process of not responding to the identification information inquiry signal of the power transmitting device 2 instead of transmitting a signal to the power transmitting device 2.

  Here, power transmission is output from the control unit 9 of the power transmission device 2, passes through the common matching unit 6 through the charging amplifier 10 and the charging matching unit 11, and is transmitted from the power transmission coil 5 to the power receiving device 3. At this time, the semiconductor switch 4 is turned off, and the charging power can be prevented from entering the communication processing unit 8.

  In the power receiving device 3, the secondary battery 17 is charged by performing processing such as rectification that generates DC power from the power transmitted by the charging unit 16.

  As can be seen from FIG. 3, in the identification information acquisition process, the semiconductor switch 4 is in a conductive state in order to transmit the identification information inquiry signal and receive the response. Further, during the power transmission process, the semiconductor switch 4 is in a conductive state and the communication processing unit 8 operates while a charge capacity confirmation signal is transmitted and a response is received. During power transmission, the semiconductor switch 4 is turned off and the power transmission unit 7 operates.

  FIG. 4 is a circuit diagram illustrating an example of a matching unit of the power transmission device according to the embodiment of the present invention.

  The power transmission unit includes a charging coupling capacitor 25 for removing direct current, a charging matching unit 23 including a low pass filter 26 (LPF) for removing high frequency noise, a charging amplifier 21 for transmitting charging power, Consists of.

  The communication processing unit includes a communication coupling capacitor 27 for removing direct current, a communication matching unit 24 including an impedance conversion unit 28 for equalizing the impedance of the output unit of the communication amplifier 22 and the power transmission coil 31, and communication. It comprised from the communication amplifier 22 for transmitting a signal.

  The common matching unit 29 is configured by a capacitor for reducing the impedance of the power transmission coil 31.

  The semiconductor switch 30 was connected in series to the communication processing unit, and the communication processing unit and the semiconductor switch were connected in parallel to the power transmission unit. Further, the shared matching unit 29 is connected between the connection portion between the power transmission unit and the communication processing unit and the power transmission coil 31.

  The power transmission coil 31 had an inductance L of 586 nH and a resistance R of 1Ω. In this case, the frequency of the charging power and the communication signal was 13.56 MHz, and the impedance of the power transmission coil antenna was 1 + j50Ω.

  By setting the capacitance of the capacitor of the shared matching unit 29 to 240 pF, the impedance of the shared matching unit 29 and the power transmission coil 31 is reduced to 1 + j1Ω.

  The matching unit for charging 23 may be multi-staged using a plurality of filters, or an impedance conversion circuit may be added to equalize the impedance of the output unit of the charging amplifier 21 and the power transmission coil 31, as necessary. May be determined as appropriate. Further, the communication matching unit 24 may add a filter circuit such as high-frequency noise removal.

  When there is an element connected in parallel to GND (ground), such as a low-pass filter 26, in the matching unit 23 for charging, an equivalent circuit that equalizes the impedance of the output unit of the communication amplifier 22 and the power transmission coil 31 when transmitting a communication signal. Therefore, it is necessary to adjust the impedance in consideration of the charging matching unit 23.

  The configuration of the charge amplifier 21 is not particularly limited, but a switching amplifier composed of a field effect transistor is preferable. Further, the configuration of the communication amplifier 22 is not particularly limited, but a linear amplifier configured with a bipolar transistor is preferable.

  From the above, it is possible to obtain a non-contact power transmission device with good transmission efficiency, in which the protection circuit for protecting the communication circuit is simplified and the manufacturing cost is reduced.

  As mentioned above, although the Example of this invention was described, this invention is not limited above, A structure change and correction and the change of a flowchart are possible in the range which does not deviate from the summary of this invention. For example, the circuit design of the shared matching unit, the charging matching unit, and the communication matching unit may be appropriately determined according to the charging power and the frequency of the communication signal. That is, it is a matter of course that various modifications and corrections that can be made by those skilled in the art are also included in the present invention.

DESCRIPTION OF SYMBOLS 1 Non-contact electric power transmission apparatus 2 Power transmission apparatus 3 Power receiving apparatus 4, 30 Semiconductor switch 5, 31 Power transmission coil 6, 29 Common matching part 7 Power transmission part 8 Communication processing part 9 Control part 10, 21 Charge amplifier 11, 23 Units 12 and 22 Communication amplifiers 13 and 24 Communication matching unit 14 Reception unit 15 Power receiving coil 16 Charging unit 17 Secondary battery 18 Communication unit 25 Charging coupling capacitor 26 Low-pass filter 27 Communication coupling capacitor 28 Impedance conversion unit

Claims (2)

  A non-contact power transmission device comprising a power transmission device having a power transmission coil and a power reception device having a power reception coil that is magnetically coupled to the power transmission coil, wherein the power transmission device further includes a power transmission unit, a communication processing unit, A control unit, a semiconductor switch, and a shared matching unit, wherein the shared matching unit is connected to the power transmission unit, one end of the semiconductor switch is connected between the shared matching unit and the power transmission unit, The other end of the semiconductor switch is connected to the communication processing unit, the power transmission coil is connected to the power transmission unit and the semiconductor switch via the shared matching unit, and the control unit is configured to connect the communication processing unit and the power transmission unit. A non-contact power transmission device, characterized in that the non-contact power transmission device is connected.   The non-contact power transmission apparatus according to claim 1, wherein the shared matching unit matches an input impedance of the shared matching unit with output impedances of the power transmission unit and the communication processing unit.

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