JP2020162311A - Wireless power transmission device and wireless power transmission system - Google Patents

Abstract

To provide a wireless power transmission device which can suppress transmission of power of a power value exceeding a first predetermined power value by wireless power transmission without stopping the wireless power transmission.SOLUTION: A wireless power transmission device comprises: a DC/DC converter; an inverter which converts DC voltage to be output from the DC/DC converter into AC voltage of a drive frequency; a power transmission coil which generates an AC magnetic field according to the AC voltage to be supplied from the inverter; and an input power control circuit which performs input power holding control for holding a power value of power to be input in the inverter at a second predetermined power value when a power value of power to be input in the DC/DC converter is larger than a first predetermined power value, or when a power value of power to be output from the DC/DC converter exceeds the first power value, in which the second power value is larger than zero, and equal to or less than the first value.SELECTED DRAWING: Figure 1

Description

The present invention relates to a wireless power transmission device and a wireless power transmission system.

Research and development of technologies related to wireless power transmission systems are being carried out. The wireless power transmission system performs wireless power transmission between a wireless power transmitting device provided with a power transmitting coil and a wireless power receiving device provided with a power receiving coil. In this specification, wireless power transmission refers to wireless power transmission.

Here, according to the current regulations of the Radio Law, various restrictions are given to a wireless power transmission system that transmits power exceeding 50 watts by wireless power transmission. This value of 50 watts may change with the times and has no special meaning. However, the wireless power transmission system is not limited to the Radio Law, and there are various cases where power exceeding the size determined for some reason (in the current regulations of the Radio Law, the above 50 watts) is transmitted by wireless power transmission. There is a possibility that restrictions will be given in the future.

Regarding this, a current limiting circuit is provided between the input power supply that supplies a voltage with a constant voltage value and the transmission coil, and when the upper limit current value set in the current limiting circuit is exceeded, the switch in the current limiting circuit is turned off. A wireless power transmission system in which a current exceeding the upper limit current value does not flow through the transmission coil is known (see Patent Document 1).

Japanese Unexamined Patent Publication No. 2015-220940

In such a wireless power transmission system, when the upper limit current value set in the current limiting circuit is exceeded, the wireless power transmission is stopped. As a result, in the wireless power transmission system, in that case, the wireless power receiving device cannot receive power from the wireless power transmitting device.

The present invention has been made in consideration of such circumstances, and suppresses the transmission of electric power having a power value exceeding a predetermined first power value by wireless power transmission without stopping the wireless power transmission. An object of the present invention is to provide a wireless power transmission device capable of providing a wireless power transmission system and a wireless power transmission system.

One aspect of the present invention is a DC / DC converter, an inverter that converts DC voltage output from the DC / DC converter into an AC voltage of a drive frequency, and an AC magnetic field according to the AC voltage supplied from the inverter. When the power value of the power input to the DC / DC converter and the power transmission coil for generating the above is larger than the predetermined first power value, or the power value of the power output from the DC / DC converter is the first power value. When it is larger than the power value, it includes an input power control circuit that performs input power holding control for holding the power value of the power input to the inverter at a predetermined second power value, and the second power value is from 0. It is a wireless power transmission device having a large power value and a power value equal to or lower than the first power value.

According to the present invention, it is possible to suppress the transmission of electric power having a power value exceeding a predetermined first power value by wireless power transmission without stopping the wireless power transmission.

It is a figure which shows an example of the structure of the wireless power transmission system 1 which concerns on 1st Embodiment. It is a figure which shows an example of the structure of the wireless power transmission system 1 which concerns on 2nd Embodiment. It is a figure which shows an example of the structure of the wireless power transmission system 1 which concerns on 3rd Embodiment. It is a figure which shows an example of the structure of the wireless power transmission system 1 which concerns on 4th Embodiment.

<First Embodiment>
Hereinafter, the first embodiment of the present invention will be described with reference to the drawings.

<Configuration of wireless power transmission system>
The configuration of the wireless power transmission system 1 according to the first embodiment will be described. FIG. 1 is a diagram showing an example of the configuration of the wireless power transmission system 1 according to the first embodiment.

The wireless power transmission system 1 includes a wireless power transmission device 10 and a wireless power receiving device 20. In the wireless power transmission system 1, electric power is transmitted from the wireless power transmission device 10 to the wireless power receiving device 20 by wireless power transmission.

The wireless power transmission device 10 is connected to a DC power source 11 that supplies a DC voltage. The wireless power transmission device 10 transmits electric power to the wireless power receiving device 20 by wireless power transmission based on a DC voltage supplied from the DC power supply 11.

The DC power supply 11 may be any power supply as long as it supplies a DC voltage, and is, for example, a DC power supply obtained by rectifying and smoothing a commercial power supply, a secondary battery, a switching power supply, or the like. The switching power supply is a switching converter or the like. The DC power supply 11 supplies a DC voltage to the wireless power transmission device 10. The wireless power transmission device 10 may be connected to an AC power source capable of supplying an AC voltage instead of being connected to the DC power source 11. In this case, the wireless power transmission device 10 transmits power to the wireless power receiving device 20 by wireless power transmission based on the AC voltage supplied from the AC power source.

Further, the wireless power transmission device 10 includes, for example, a power transmission circuit 12, a power transmission coil unit 13, and a power transmission side communication unit 14. The wireless power transmission device 10 may be configured to include other circuits in addition to the power transmission circuit 12, the power transmission coil unit 13, and the power transmission side communication unit 14.

The power transmission circuit 12 converts the DC voltage supplied from the DC power supply 11 into an AC voltage having a drive frequency. The power transmission circuit 12 includes, for example, a DC (Direct Current) / DC converter 121, an inverter 122, an input power control circuit 123, and a first control circuit 124. The power transmission circuit 12 may be configured to include other circuits in addition to the DC / DC converter 121, the inverter 122, the input power control circuit 123, and the first control circuit 124. For example, the wireless power transmission device 10 further includes a circuit (for example, an AC (Alternating Current) / DC converter or the like) that converts an AC voltage into a DC voltage when connected to an AC power source instead of the DC power source 11.

The DC / DC converter 121 converts the DC voltage supplied from the DC power supply 11 into a DC voltage having a magnitude corresponding to the control by the input power control circuit 123 or the first control circuit 124. The DC / DC converter 121 supplies the converted DC voltage to the inverter 122.

The inverter 122 is, for example, a switching circuit (full bridge circuit, half bridge circuit, etc.) in which switching elements are bridge-connected. The inverter 122 converts the DC voltage supplied from the DC / DC converter 121 into an AC voltage having a drive frequency. The inverter 122 supplies the converted AC voltage to the power transmission coil unit 13.

The input power control circuit 123 includes, for example, a first power detection circuit 123A and a second control circuit 123B.

The first power detection circuit 123A detects the power value of the DC power output from the DC / DC converter 121. For example, the first power detection circuit 123A detects each of the voltage value of the DC voltage output from the DC / DC converter 121 and the current value of the DC current output from the DC / DC converter 121. The first power detection circuit 123A calculates the power value of the DC power output from the DC / DC converter 121 based on the detected voltage value and the detected current value. The first power detection circuit 123A outputs a signal indicating the calculated power value to the second control circuit 123B.

The second control circuit 123B acquires the signal output from the first power detection circuit 123A. The second control circuit 123B does nothing when the acquired power value indicated by the signal is equal to or less than the predetermined first power value. Here, the first power value may be any power value. In the following, as an example, a case where the first power value is 50 watts will be described. The first power value may be a power value smaller than 50 watts or a power value larger than 50 watts. On the other hand, the second control circuit 123B performs input power holding control when the acquired power value indicated by the signal is larger than the first power value. The input power holding control is a control for holding the power value of the power input to the inverter 122 at a predetermined second power value. Even when the second control circuit 123B performs input power holding control, the power value of the power input to the inverter 122 may fluctuate irregularly. The second control circuit 123B, which is performing the input power holding control, controls so that the power value returns to the second power value when such an irregular fluctuation of the power value occurs. That is, the input power holding control also includes a control for returning the fluctuated power value to the second power value. Here, the second power value may be any power value as long as it is a power value greater than 0 and a power value equal to or less than the first power value. In the following, as an example, a case where the second power value is 3 watts smaller than the first power value (47 watts in this example) will be described. More specifically, in this case, the second control circuit 123B controls the input power holding control to hold, for example, the power value of the DC power output from the DC / DC converter 121 at the second power value. This is performed for the DC converter 121. As a result, the wireless power transmission device 10 can prevent the wireless power transmission from transmitting power having a power value exceeding the first power value without stopping the wireless power transmission.

The first control circuit 124 controls the DC / DC converter 121 so that the output to the load 24 from the wireless power receiving device 20 that receives AC power via the alternating magnetic field generated by the power transmission coil L1 becomes a constant voltage. Perform feedback control. More specifically, the first control circuit 124 acquires a control signal received from the wireless power receiving device 20 by the power transmission side communication unit 14 described later. This control signal is a signal related to the control of the DC voltage supplied by the DC / DC converter 121 to the inverter 122. The first control circuit 124 performs feedback control based on the acquired control signal on the DC / DC converter 121, and changes the voltage value of the DC voltage as needed. As a result, the first control circuit 124 uses the DC / DC converter 121 so that the output to the load 24 from the wireless power receiving device 20 that receives AC power via the alternating magnetic field generated by the power transmission coil L1 becomes a constant voltage. Performs feedback control to control. The first control circuit 124 sets the DC / DC converter 121 so that the output to the load 24 from the wireless power receiving device 20 that receives AC power via the alternating magnetic field generated by the power transmission coil L1 becomes a constant current. It may be configured to perform feedback control to control.

However, the input power holding control by the second control circuit 123B described above has priority over the feedback control for the DC / DC converter 121 by the first control circuit 124. As a method of prioritizing the input power holding control over the feedback control, a known method (for example, a method of prioritizing using a logic circuit, a method of prioritizing by a microcomputer, etc.) may be used, and a method to be developed from now on. May be used. Therefore, detailed description of the method of giving priority to the input power holding control over the feedback control will be omitted. The first control circuit 124 is an example of a control circuit. Further, the first control circuit 124 may be integrally configured with the above-mentioned second control circuit 123B.

The power transmission coil unit 13 includes, for example, a power transmission coil unit 131. The power transmission coil unit 13 may be configured to include other circuits in addition to the power transmission coil unit 131.

The power transmission coil unit 131 includes a coil that functions as an antenna for wireless power transmission as a power transmission coil L1 (not shown in FIG. 1). That is, the power transmission coil L1 generates an alternating magnetic field according to the alternating voltage supplied from the inverter 122. As a result, the power transmission coil unit 131 transmits power to the wireless power receiving device 20 by wireless power transmission via the power transmission coil L1. The transmission coil unit 131 includes a capacitor as a circuit element that constitutes a transmission side resonance circuit together with the transmission coil L1, a magnetic body that enhances the magnetic coupling between the transmission coil L1 and the power receiving coil L2 described later, and a transmission coil. It may be configured to include at least a part of an electromagnetic shield (for example, a metal plate or the like) that suppresses leakage of the magnetic field generated by L1 to the outside.

The power transmission side communication unit 14 is a communication circuit (or communication device) that transmits / receives signals by, for example, wireless communication, optical communication, electromagnetic induction, sound, vibration, or the like. The power transmission side communication unit 14 outputs, for example, a control signal received from the wireless power receiving device 20 to the first control circuit 124.

The wireless power receiving device 20 can be connected to the load 24. In the example shown in FIG. 1, the wireless power receiving device 20 is connected to the load 24. The wireless power receiving device 20 includes a power receiving coil unit 21, a power receiving circuit 22, and a power receiving side communication unit 23. The wireless power receiving device 20 may be configured to include a load 24.

The power receiving coil unit 21 includes, for example, a power receiving coil unit 211. The power receiving coil unit 21 may be configured to include another circuit in addition to the power receiving coil unit 211.

The power receiving coil unit 211 includes a coil that functions as an antenna for wireless power transmission as a power receiving coil L2 (not shown in FIG. 1). The power receiving coil unit 211 receives power from the wireless power transmission device 10 by wireless power transmission via the power receiving coil L2. The power receiving coil unit 211 includes a capacitor as a circuit element that constitutes a power receiving side resonance circuit together with the power receiving coil L2, a magnetic body that enhances the magnetic coupling between the power receiving coil L2 and the power transmitting coil L1, and the power receiving coil L2. It may be configured to include at least a part of an electromagnetic shield (for example, a metal plate or the like) that suppresses leakage of the generated magnetic field to the outside.

The power receiving circuit 22 includes, for example, a rectifier circuit 221 and a control comparison unit 222. The power receiving circuit 22 may be configured to include other circuits in addition to the rectifier circuit 221 and the control comparison unit 222.

The rectifier circuit 221 is connected to the power receiving coil unit 211. The rectifier circuit 221 converts the AC voltage received by the power receiving coil unit 211 via the power receiving coil L2 into a DC voltage. The rectifier circuit 221 supplies the converted DC voltage to the load 24. The rectifier circuit 221 is a converter, and is composed of, for example, a bridge diode (not shown) and a smoothing capacitor (not shown). The rectifier circuit 221 full-wave rectifies the AC voltage received by the power receiving coil unit 211, and smoothes the full-wave rectified voltage with a smoothing capacitor. The rectifier circuit 221 supplies the rectified DC voltage to the load 24.

The control comparison unit 222 detects the DC voltage supplied from the rectifier circuit 221 to the load 24. The control comparison unit 222 compares the detected DC voltage with the reference voltage (target voltage), and generates a control signal based on the difference between the DC voltage and the reference voltage. The control comparison unit 222 transmits the generated control signal to the wireless power transmission device 10 via the power receiving side communication unit 23. That is, in the wireless power transmission device 10, the first control circuit 124 controls the DC voltage output to the inverter 122 by the DC / DC converter 121 so that the difference indicated by the control signal acquired via the power transmission side communication unit 14 becomes small. To do. The control comparison unit 222 may be configured to detect the current supplied from the rectifier circuit 221 to the load 24, or may be configured to detect the power supplied from the rectifier circuit 221 to the load 24.

The power receiving side communication unit 23 is a communication circuit (or communication device) that transmits / receives signals by, for example, wireless communication, optical communication, electromagnetic induction, sound, vibration, or the like. The power receiving side communication unit 23 transmits, for example, a control signal acquired from the control comparison unit 222 to the wireless power transmission device 10.

A DC voltage is supplied to the load 24 from the rectifier circuit 221. The load 24 is, for example, a rechargeable secondary battery (for example, a lithium ion battery, a lithium polymer battery, etc.). The load 24 may be another device that operates according to the DC voltage instead of the secondary battery.

The rectifier circuit 221 and the load 24 may be provided with a conversion circuit (for example, a DC / DC converter, a DC / AC inverter, or the like) that converts the output of the rectifier circuit 221.

With the above configuration, in the wireless power transmission device 10 according to the first embodiment (that is, the wireless power transmission system 1 according to the first embodiment), the power value of the power output from the DC / DC converter 121 is the first. If it is larger than the power value, the input power holding control for holding the power value of the power input to the inverter 122 at the second power value is performed. As a result, the wireless power transmission device 10 can prevent the wireless power transmission from transmitting power having a power value exceeding the first power value without stopping the wireless power transmission. In other words, the wireless power transmission device 10 can suppress the decrease in the efficiency of wireless power transmission and the transmission of power having a power value exceeding the first power value by wireless power transmission. it can.

The input power control circuit 123 further includes a notification circuit for notifying that the input power holding control is being performed by the input power control circuit 123 when the input power holding control is being performed by the input power control circuit 123. It may be a configuration. In this case, the second control circuit 123B outputs a signal to the notification circuit indicating that the input power holding control is being performed by the input power control circuit 123. Then, when the signal is acquired, the notification circuit notifies that the input power holding control is being performed by the input power control circuit 123. In this case, for example, the notification circuit outputs a signal indicating that the input power holding control is being performed by the input power control circuit 123 to another device, so that the input power holding control is performed by the input power control circuit 123. It may be configured to notify that it is being performed. Further, the notification circuit may be configured to notify that the input power holding control is being performed by the input power control circuit 123, for example, by illuminating an LED (Light Emitting Diode) in this case. By another method, the input power control circuit 123 may be configured to notify that the input power holding control is being performed. The target for notifying that the notification circuit is performing the input power holding control by the input power control circuit 123 may be a user, a person other than the user, or another device. It may be.

<Second Embodiment>
Hereinafter, the second embodiment of the present invention will be described with reference to the drawings. In the second embodiment, the same functional parts as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

FIG. 2 is a diagram showing an example of the configuration of the wireless power transmission system 1 according to the second embodiment.

The power transmission circuit 12 according to the second embodiment includes an input power control circuit 125 instead of the input power control circuit 123. Here, in the second embodiment, the input power control circuit 125 is composed of the second power detection circuit 125A and the second control circuit 125B, which will be described later. Therefore, in the second embodiment, the DC voltage supplied from the DC power supply 11 is output to the DC / DC converter 121 via the input power control circuit 125. The power transmission circuit 12 may be configured to include other circuits in addition to the DC / DC converter 121, the inverter 122, the first control circuit 124, and the input power control circuit 125.

The input power control circuit 125 includes, for example, a second power detection circuit 125A and a second control circuit 125B.

The second power detection circuit 125A detects the power value of the DC power input to the DC / DC converter 121. For example, in the second power detection circuit 125A, the voltage value of the DC voltage input from the DC power supply 11 to the DC / DC converter 121 and the current value of the DC current input from the DC power supply 11 to the DC / DC converter 121 Detect each. The second power detection circuit 125A calculates the power value of the DC power output from the DC power supply 11 based on the detected voltage value and the detected current value. The second power detection circuit 125A outputs a signal indicating the calculated power value to the second control circuit 125B.

The second control circuit 125B acquires the signal output from the second power detection circuit 125A. The second control circuit 125B does nothing when the acquired power value indicated by the signal is equal to or less than the first power value. On the other hand, when the acquired power value indicated by the signal is larger than the first power value, the second control circuit 125B performs the above-mentioned input power holding control. As a result, the wireless power transmission device 10 can prevent the wireless power transmission from transmitting power having a power value exceeding the first power value without stopping the wireless power transmission.

With the above configuration, in the wireless power transmission device 10 according to the second embodiment (that is, the wireless power transmission system 1 according to the first embodiment), the power value of the power input to the DC / DC converter 121 is the first. If it is larger than the power value, the input power holding control for holding the power value of the power input to the inverter 122 at the second power value is performed. As a result, the wireless power transmission device 10 can prevent the wireless power transmission from transmitting power having a power value exceeding the first power value without stopping the wireless power transmission. In other words, the wireless power transmission device 10 can suppress the decrease in the efficiency of wireless power transmission and the transmission of power having a power value exceeding the first power value by wireless power transmission. it can.

When the input power control circuit 125 according to the second embodiment is controlled so that the voltage output from the DC power supply 11 becomes a constant value (that is, the DC power supply 11 outputs a DC voltage having a constant voltage value). If this is the case), a current detection circuit may be provided instead of the second power detection circuit 125A. In this case, the current detection circuit detects the current value of the current output from the DC power supply 11. The current detection circuit outputs a signal indicating the detected current value to the second control circuit 125B. Then, the second control circuit 125B in this case does nothing when the current value indicated by the signal acquired from the current detection circuit is equal to or less than the predetermined first current value. On the other hand, when the current value indicated by the signal acquired from the current detection circuit is larger than the first current value, the second control circuit 125B performs the above-mentioned input power holding control. Here, for the first current value, for example, when the voltage output from the DC power supply 11 is controlled to be a constant value, the first power value is divided by the voltage value of the DC voltage output from the DC power supply 11. It is the current value obtained by this. As a result, the wireless power transmission device 10 according to the second embodiment detects the current value of the current output from the DC power supply 11 when the voltage output from the DC power supply 11 is controlled to be a constant value. Therefore, it is possible to prevent the wireless power transmission from transmitting power having a power value exceeding the first power value without stopping the wireless power transmission. The first current value may have a configuration determined by another method.

Further, the input power control circuit 125 further includes a notification circuit for notifying that the input power holding control is performed by the input power control circuit 125 when the input power holding control is performed by the input power control circuit 125. It may be a configuration. In this case, the second control circuit 125B outputs a signal to the notification circuit indicating that the input power holding control is being performed by the input power control circuit 125. Then, when the signal is acquired, the notification circuit notifies that the input power holding control is being performed by the input power control circuit 125. In this case, for example, the notification circuit outputs a signal indicating that the input power holding control is performed by the input power control circuit 125 to another device, so that the input power holding control is performed by the input power control circuit 125. It may be configured to notify that it is being performed. Further, the notification circuit may be configured to notify that the input power holding control is being performed by the input power control circuit 125, for example, by illuminating the LED in this case, and may be configured by another method. The input power control circuit 125 may be configured to notify that the input power holding control is being performed. The target for notifying that the notification circuit is performing the input power holding control by the input power control circuit 125 may be a user, a person other than the user, or another device. It may be.

<Third Embodiment>
Hereinafter, the third embodiment of the present invention will be described with reference to the drawings. In the third embodiment, the same functional parts as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

FIG. 3 is a diagram showing an example of the configuration of the wireless power transmission system 1 according to the third embodiment.

The power transmission circuit 12 according to the third embodiment includes an input power control circuit 126 instead of the input power control circuit 123. However, in this case, the DC / DC converter 121 according to the third embodiment outputs the converted DC voltage to the input power control circuit 126, not to the inverter 122. The power transmission circuit 12 may be configured to include other circuits in addition to the DC / DC converter 121, the inverter 122, the first control circuit 124, and the input power control circuit 126.

The input power control circuit 126 detects the power value of the DC power output from the DC / DC converter 121. For example, the input power control circuit 126 detects each of the voltage value of the DC voltage output from the DC / DC converter 121 and the current value of the DC current output from the DC / DC converter 121. The input power control circuit 126 calculates the power value of the DC power output from the DC / DC converter 121 based on the detected voltage value and the detected current value. When the calculated power value is equal to or less than the first power value, the input power control circuit 126 supplies the power output from the DC / DC converter 121 to the inverter 122 as it is. On the other hand, when the calculated power value is larger than the first power value, the input power control circuit 126 performs the second input power holding control. The second input power holding control is a control for holding the power value of the power input to the inverter 122 by the input power control circuit 126 in the second power value. More specifically, in this case, the input power control circuit 126 converts the power value of the DC power output from, for example, the DC / DC converter 121 into the DC power of the second power value as the second input power holding control. Convert. Then, the input power control circuit 126 supplies the converted DC power to the inverter 122. As a result, the wireless power transmission device 10 can prevent the wireless power transmission from transmitting power having a power value exceeding the first power value without stopping the wireless power transmission.

The input power control circuit 126 includes, for example, a DC / DC converter that converts a DC voltage output from the DC / DC converter 121 into a DC voltage having a voltage value equal to or lower than the voltage value of the DC voltage. Further, the input power control circuit 126 includes, for example, a power detection circuit that detects the power value of the power output from the DC / DC converter 121. Further, the input power control circuit 126 includes, for example, a control circuit that controls the voltage value of the DC voltage output from the DC / DC converter according to the power value detected by the power detection circuit. As a result, the input power control circuit 126 can perform the above-mentioned second input power holding control.

With the above configuration, in the wireless power transmission device 10 according to the third embodiment (that is, the wireless power transmission system 1 according to the first embodiment), the power value of the power output from the DC / DC converter 121 is the first. If it is larger than the power value, the second input power holding control for holding the power value of the power input to the inverter 122 at the second power value is performed. As a result, the wireless power transmission device 10 can prevent the wireless power transmission from transmitting power having a power value exceeding the first power value without stopping the wireless power transmission. In other words, the wireless power transmission device 10 can suppress the decrease in the efficiency of wireless power transmission and the transmission of power having a power value exceeding the first power value by wireless power transmission. it can.

The input power control circuit 126 notifies that when the input power control circuit 126 is performing the second input power holding control, the input power control circuit 126 is performing the second input power holding control. The configuration may further include a circuit. In this case, the control circuit included in the input power control circuit 126 outputs a signal to the notification circuit indicating that the second input power holding control is being performed by the input power control circuit 126. Then, when the signal is acquired, the notification circuit notifies that the input power control circuit 126 is performing the second input power holding control. In this case, the notification circuit outputs a signal indicating that the second input power holding control is being performed by the input power control circuit 126 to another device, so that the second input is input by the input power control circuit 126. It may be configured to notify that the power holding control is being performed. Further, even if the notification circuit is configured to notify that the second input power holding control is being performed by the input power control circuit 126, for example, by illuminating an LED (Light Emitting Diode) in this case. Often, the configuration may be such that the input power control circuit 126 notifies that the second input power holding control is being performed by another method. The target for notifying that the notification circuit is performing the input power holding control by the input power control circuit 126 may be a user, a person other than the user, or another device. It may be.

<Fourth Embodiment>
Hereinafter, the fourth embodiment of the present invention will be described with reference to the drawings. In the fourth embodiment, the same functional parts as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

FIG. 4 is a diagram showing an example of the configuration of the wireless power transmission system 1 according to the fourth embodiment.

The power transmission circuit 12 according to the fourth embodiment includes an input power control circuit 127 instead of the input power control circuit 123. However, in this case, the DC power supply 11 according to the fourth embodiment outputs the DC voltage to the input power control circuit 127, not to the DC / DC converter 121.
The power transmission circuit 12 may be configured to include other circuits in addition to the DC / DC converter 121, the inverter 122, the first control circuit 124, and the input power control circuit 127.

The input power control circuit 127 detects the power value of the DC power input from the DC power supply 11 to the DC / DC converter 121. For example, the input power control circuit 127 detects each of the voltage value of the DC voltage input to the DC / DC converter 121 and the current value of the DC current input to the DC / DC converter 121. The input power control circuit 127 calculates the power value of the DC power output from the DC power supply 11 based on the detected voltage value and the detected current value. When the calculated power value is equal to or less than the first power value, the input power control circuit 127 supplies the power output from the DC power supply 11 to the DC / DC converter 121 as it is. On the other hand, when the calculated power value is larger than the first power value, the input power control circuit 127 performs the third input power holding control. The third input power holding control is a control for holding the power value of the power input to the inverter 122 at the second power value. More specifically, in this case, the input power control circuit 127 converts the power value of the DC power output from the DC power supply 11 into the DC power of the second power value as the third input power holding control. .. Then, the input power control circuit 127 supplies the converted DC power to the DC / DC converter 121. As a result, the wireless power transmission device 10 can prevent the wireless power transmission from transmitting power having a power value exceeding the first power value without stopping the wireless power transmission.

The input power control circuit 127 includes, for example, a DC / DC converter that converts a DC voltage output from the DC power supply 11 into a DC voltage having a voltage value equal to or lower than the voltage value of the DC voltage. Further, the input power control circuit 127 includes, for example, a power detection circuit that detects the power value of the DC power output from the DC power supply 11. Further, the input power control circuit 127 includes, for example, a control circuit that controls the voltage value of the voltage output from the DC / DC converter according to the power value detected by the power detection circuit. As a result, the input power control circuit 127 can perform the above-mentioned third input power holding control.

With the above configuration, in the wireless power transmission device 10 according to the fourth embodiment (that is, the wireless power transmission system 1 according to the first embodiment), the power value of the power input to the DC / DC converter 121 is the first. If it is larger than the power value, the third input power holding control for holding the power value of the power input to the inverter 122 at the second power value is performed. As a result, the wireless power transmission device 10 can prevent the wireless power transmission from transmitting power having a power value exceeding the first power value without stopping the wireless power transmission. In other words, the wireless power transmission device 10 can suppress the decrease in the efficiency of wireless power transmission and the transmission of power having a power value exceeding the first power value by wireless power transmission. it can.

In the input power control circuit 127 according to the fourth embodiment, when the wireless power transmission device 10 is controlled so that the voltage output from the DC power supply 11 becomes a constant value (that is, the DC power supply 11 has a constant voltage value). (When the DC voltage is output), the current value of the current input from the DC power supply 11 to the DC / DC converter 121 may be detected. In this case, for example, when the detected current value is equal to or less than the above-mentioned first current value, the input power control circuit 127 supplies the power output from the DC power supply 11 to the DC / DC converter 121 as it is. On the other hand, when the detected current value is larger than the first current value, the input power control circuit 127 performs the third input power holding control. As a result, in the wireless power transmission device 10 according to the fourth embodiment, when the wireless power transmission device 10 is controlled so that the voltage output from the DC power supply 11 becomes a constant value, the current of the current output from the DC power supply 11 By detecting the value, it is possible to prevent the wireless power transmission from transmitting power having a power value exceeding the first power value without stopping the wireless power transmission.

Further, the input power control circuit 127 provides a notification circuit for notifying that the input power control circuit 127 is performing the third input power holding control when the input power holding control is being performed by the input power control circuit 127. It may be further provided. In this case, the control circuit included in the input power control circuit 127 outputs a signal to the notification circuit indicating that the input power control circuit 127 is performing the third input power holding control. Then, when the signal is acquired, the notification circuit notifies that the input power control circuit 127 is performing the third input power holding control. In this case, for example, the notification circuit outputs a signal indicating that the third input power holding control is being performed by the input power control circuit 127 to another device, so that the third input is input by the input power control circuit 127. It may be configured to notify that the power holding control is being performed. Further, the notification circuit may be configured to notify that the third input power holding control is being performed by the input power control circuit 127, for example, by illuminating the LED in this case, or another method. May be configured to notify that the third input power holding control is being performed by the input power control circuit 127. The target for notifying that the notification circuit is performing the input power holding control by the input power control circuit 127 may be a user, a person other than the user, or another device. It may be.

As described above, the wireless power transmission device according to each embodiment described above (the wireless power transmission device 10 in the example described above) is a DC / DC converter (DC / DC converter 121 in the example described above). And an inverter that converts the DC voltage output from the DC / DC converter into an AC voltage of the drive frequency (Inverter 122 in the example described above), and an AC magnetic field is generated according to the AC voltage supplied from the inverter. When the power value of the power input to the power transmission coil (transmission coil L1 in the example described above) and the DC / DC converter is larger than the predetermined first power value, or the power output from the DC / DC converter. When the power value of is larger than the first power value, the input power holding control that holds the power value of the power input to the inverter at a predetermined second power value (in the example described above, the input power holding control, the second Input power control circuit that performs input power holding control, third input power holding control) (in the example described above, input power control circuit 123, input power control circuit 125, input power control circuit 126, input power control circuit 127) The second power value is a power value greater than 0 and equal to or less than the first power value. As a result, the wireless power transmission device 10 can suppress the transmission of electric power having a power value exceeding a predetermined first power value by wireless power transmission without stopping the wireless power transmission.

Also, in a wireless power transmission device, a configuration may be used in which the first power value is 50 watts.

Further, the wireless power transmission device is further provided with a notification circuit for notifying that the input power holding control is performed by the input power control circuit when the input power holding control is performed by the input power control circuit. May be done.

Further, the wireless power transmission device further includes a first power detection circuit (first power detection circuit 123A in the example described above) for detecting the power value of the power output from the DC / DC converter, and is an input power control circuit. May use a configuration in which input power holding control is performed when the power value detected by the first power detection circuit is larger than the first power value.

Further, the wireless power transmission device further includes a second power detection circuit (second power detection circuit 125A in the example described above) for detecting the power value of the power input to the DC / DC converter, and is an input power control circuit. May use a configuration in which input power holding control is performed when the power value detected by the second power detection circuit is larger than the first power value.

Further, in the wireless power transmission device, even if the configuration is used, the input power control circuit controls to hold the power value of the power output from the DC / DC converter to the inverter at the second power value as the input power holding control. Good.

Further, the wireless power transmission device includes a power receiving coil (power receiving coil L2 in the above-described example) that receives AC power via an AC magnetic field generated by the transmission coil (in the above-described example, the wireless power transmitting device). A control circuit (first control circuit 124 in the example described above) that controls the DC / DC converter so that the output from the wireless power receiving device 20) becomes a constant voltage or a constant current is further provided and input. A configuration may be used in which the input power holding control by the power control circuit takes precedence over the feedback control by the control circuit.

Further, the wireless power transmission device is supplied from a DC / DC converter that outputs a DC voltage having a constant voltage value, an inverter that converts the DC voltage output from the DC / DC converter into an AC voltage of a drive frequency, and an inverter. When the current value of the power transmission coil that generates the AC magnetic field according to the AC voltage and the current input to the DC / DC converter is larger than the predetermined first current value, the power value of the power input to the inverter is set to the predetermined first value. The second power value is a power value greater than 0 and a power value equal to or less than a predetermined first value, comprising an input power control circuit for performing input power holding control for holding the power value. As a result, the wireless power transmission device can prevent the wireless power transmission from transmitting power having a power value exceeding a predetermined first power value without stopping the wireless power transmission.

Although the embodiments of the present invention have been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and changes, substitutions, deletions, etc. are made as long as the gist of the present invention is not deviated. May be done.

1 ... wireless power transmission system, 10 ... wireless power transmission device, 11 ... DC power supply, 12 ... power transmission circuit, 13 ... power transmission coil unit, 14 ... power transmission side communication unit, 20 ... wireless power reception device, 21 ... power reception coil unit, 22 ... Power receiving circuit, 23 ... Power receiving side communication unit, 24 ... Load, 121 ... DC / DC converter, 122 ... Inverter, 123, 125, 126, 127 ... Input power control circuit, 123A ... First power detection circuit, 123B, 125B ... 2nd control circuit, 124 ... 1st control circuit, 125A ... 2nd power detection circuit, 131 ... power transmission coil unit, 211 ... power receiving coil unit, 221 ... rectifying circuit, 222 ... control comparison unit, L1 ... power transmission coil, L2 ... Power receiving coil

Claims (9)

DC / DC converter and
An inverter that converts the DC voltage output from the DC / DC converter into an AC voltage with a drive frequency,
A power transmission coil that generates an AC magnetic field according to the AC voltage supplied from the inverter.
When the power value of the power input to the DC / DC converter is larger than the predetermined first power value, or when the power value of the power output from the DC / DC converter is larger than the first power value, the said An input power control circuit that performs input power holding control that holds the power value of the power input to the inverter at a predetermined second power value, and
With
The second power value is a power value greater than 0 and equal to or less than the first power value.
Wireless power transmission device. The first power value is 50 watts.
The wireless power transmission device according to claim 1. When the input power holding control is performed by the input power control circuit, a notification circuit for notifying that the input power holding control is performed by the input power control circuit is further provided.
The wireless power transmission device according to claim 1 or 2. A first power detection circuit for detecting the power value of the power output from the DC / DC converter is further provided.
The input power control circuit performs the input power holding control when the power value detected by the first power detection circuit is larger than the first power value.
The wireless power transmission device according to any one of claims 1 to 3. A second power detection circuit for detecting the power value of the power input to the DC / DC converter is further provided.
The input power control circuit performs the input power holding control when the power value detected by the second power detection circuit is larger than the first power value.
The wireless power transmission device according to any one of claims 1 to 3. The input power control circuit performs control for holding the power value of the power output from the DC / DC converter to the inverter at the second power value as the input power holding control.
The wireless power transmission device according to any one of claims 1 to 5. Feedback control is performed to control the DC / DC converter so that the output from the wireless power receiving device including the power receiving coil for receiving AC power via the alternating magnetic field generated by the power transmission coil becomes a constant voltage or a constant current. With more control circuits
The input power holding control by the input power control circuit has priority over the feedback control by the control circuit.
The wireless power transmission device according to any one of claims 1 to 6. A DC / DC converter that outputs a DC voltage with a constant voltage value,
An inverter that converts the DC voltage output from the DC / DC converter into an AC voltage with a drive frequency,
A power transmission coil that generates an AC magnetic field according to the AC voltage supplied from the inverter.
When the current value of the current input to the DC / DC converter is larger than the predetermined first current value, the input power holding control for holding the power value of the power input to the inverter at the predetermined second power value is performed. Input power control circuit and
With
The second power value is a power value greater than 0 and a power value equal to or less than a predetermined first value.
Wireless power transmission device. The wireless power transmission device according to any one of claims 1 to 8.
Wireless power receiving device and
Wireless power transfer system with.

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