JP2023045466A - Wireless power transmission device and wireless power transmission system - Google Patents

Abstract

To provide a wireless power transmission device and a wireless power transmission system in which a large rating of a component of a device for charging a secondary battery is not required.SOLUTION: A wireless power transmission device according to an embodiment includes a communication unit and a control unit. The communication unit receives information about the voltage of a secondary battery which is charged with wirelessly transmitted power. On the basis of the information received by the communication unit, the control unit controls power to be transmitted.SELECTED DRAWING: Figure 2

Description

TECHNICAL FIELD Embodiments of the present invention relate to a wireless power transmission device and a wireless power transmission system that wirelessly transmit power to electrical equipment.

A wireless power transmission device that wirelessly transmits (feeds) power to an electrical device is known. There are several methods of controlling transmission power. For example, when the transmission power is controlled to be constant, the power received by the power receiving side is also constant.

Recently, power may be wirelessly transmitted to a charging device that charges a secondary battery. As a characteristic of the secondary battery, when the above-described control for keeping the transmission power constant is performed, the charging current for charging decreases as the battery voltage rises with charging.

In this way, when a secondary battery is charged by transmitting constant transmission power, the receiving current changes. Therefore, the charging device on the power receiving side increases the component rating so that it can handle changes in the receiving current. I needed it.

Conventionally, measures such as inserting a DC/DC converter between the charging device and the secondary battery have been considered, but the number of parts increases compared to a simple rectifier. As another countermeasure, feedback control based on the received current is conceivable, but in this case, a new current sensor is required, leading to an increase in size and cost.

Wireless Charging System for Lithium Ion Secondary Battery SCiB (Registered Trademark) Module, Toshiba Review Vol.75 No.4

SUMMARY OF THE INVENTION An object of the present invention is to provide a wireless power transmission device and a wireless power transmission system that do not require a high component rating for a device that charges a secondary battery.

A wireless power transmission device according to an embodiment includes a communication unit and a control unit. The communication unit receives information on the voltage of a secondary battery charged by wirelessly transmitted power. The control unit controls power to be transmitted based on the information received by the communication unit.

1 is a diagram showing a configuration example of a wireless power transmission system according to the present invention; FIG. FIG. 2 is a diagram showing the detailed configuration of the wireless power transmission system shown in FIG. 1; FIG. 3 is a diagram for explaining switching of the inverter circuit shown in FIG. 2; FIG. 3 is a diagram for explaining switching of the inverter circuit shown in FIG. 2; FIG. 2 is a diagram for explaining an outline of transmission power control of the wireless power transmission system shown in FIG. 1; 2 is a flowchart for explaining the operation of the wireless power transmission system shown in FIG. 1; FIG. 4 is a diagram for explaining component ratings required for components on the power receiving side of a conventional wireless power transmission system; FIG. 2 is a diagram for explaining component ratings required for power-receiving-side components of the wireless power transmission system shown in FIG. 1; 4 is a flowchart for explaining a modification of the operation of the wireless power transmission system shown in FIG. 1;

An embodiment will be described below with reference to the drawings.
FIG. 1 shows an example of a wireless power transmission system according to an embodiment. (Plug-in hybrid vehicles) are charged by wireless power transmission. This wireless power transmission system includes a wireless power transmission device 100 , a wireless power receiving device 200 , and a power-supplied device 300 .

The wireless power receiving device 200 and the power-supplied device 300 are mounted on an AGV or the like.
The wireless power transmission device 100 includes a power transmission unit 100a and power transmission pads 100b.

The power transmission unit 100 a converts power supplied from a commercial power source or the like into power for wireless transmission, and controls transmission power based on information obtained by communicating with the wireless power receiving device 200 .

Power transmission pad 100b includes a resonance circuit that magnetically couples with power reception pad 200b of wireless power reception device 200 by electromagnetic induction, and transmits power supplied from power transmission unit 100a to wireless power reception device 200 in a contactless manner.

The wireless power receiving device 200 includes a power receiving unit 200a and a power receiving pad 200b.
The power receiving pad 200b includes a resonance circuit that magnetically couples with the power transmitting pad 100b by electromagnetic induction, and receives power wirelessly transmitted.

The power receiving unit 200a communicates with the power transmitting unit 100a to notify the voltage of the secondary battery 300a, rectifies the AC power obtained by the power receiving pad 200b, converts it to DC power, and converts it into DC power. 300a is charged.

The power-supplied device 300 includes a secondary battery 300a, a motor drive circuit 300b, a motor 300c, and the like.

The secondary battery 300a is, for example, a secondary battery such as an SCiB (registered trademark), a lithium ion battery, or a nickel metal hydride battery, and supplies accumulated power to the motor drive circuit 300b, the motor 300c, and the like.

The motor drive circuit 300b uses the power stored in the secondary battery 300a to control the power supplied to the motor 300c used for driving the wheels of the AGV.

Next, with reference to FIG. 2, the configuration of the wireless power transmission system according to the embodiment will be described in more detail.

As described above, the wireless power transmission device 100 includes the power transmission unit 100a and the power transmission pad 100b, which will be described in more detail.

The power transmission unit 100 a includes a single-phase (or three-phase) rectifier 110 , an inverter circuit 120 , a power transmission side sensor circuit 130 , a gate drive circuit 140 , a power transmission side communication circuit 150 , a storage section 160 and a control circuit 170 .

The single-phase (or three-phase) rectifier 110 converts the AC voltage supplied from the single-phase (or three-phase) system power supply P into a DC voltage, and inputs the DC voltage to the inverter circuit 120 .

The inverter circuit 120 converts the DC voltage output from the single-phase (or three-phase) rectifier 110 into an AC voltage of any frequency, and is controlled by a gate drive circuit 140, which will be described later.

Specifically, the inverter circuit 120 includes, for example, insulated gate bipolar transistors (IGBTs) as four switching elements, and the gates of these four transistors are controlled by respective switch timings Q1 to Q4. By doing so, the DC voltage is converted into an AC voltage of any frequency. The switching element is not limited to the above, and a MOS-FET (Metal Oxide Semiconductor-Field Effect Transistor) may be used.

For example, as shown in FIG. 3(a), by turning on four gates at respective switch timings Q1 to Q4, AC voltages as shown in FIG. 3(b) can be output. Also, for example, if you want to maximize the output power, as shown in FIG. It can output AC voltage as shown.

The power transmission side sensor circuit 130 detects the DC voltage and DC current input to the inverter circuit 120 as a power transmission voltage S001 and a power transmission current S002, respectively, and outputs these detection results to the control circuit 170. FIG.

Gate drive circuit 140 switches the gate of inverter circuit 120 in accordance with an instruction from control circuit 170, which will be described later, to control the AC voltage output from inverter circuit 120. FIG.

The power transmission side communication circuit 150 communicates with the power receiving unit 200a, and transmits information notified from the control circuit 170 to the wireless power receiving device 200, or transmits information received from the wireless power receiving device 200 to the control circuit 170. to notify. Infrared communication, Bluetooth (registered trademark), wireless LAN, etc. can be considered as communication methods, and a communication module corresponding to the communication method is installed.

The storage unit 160 stores software of the control circuit 170, data generated along with the operation of the software, various parameters (parameters 160a), data related to the operation state and operation status of the wireless power transmission device 100, and other information processing. Storage devices such as RAM (Random Access Memory), ROM (Read Only Memory), flash memory such as SSD (Solid State Drive), and HDD (Hard Disk Drive). They are provided in combination according to the characteristics of the data.

The control circuit 170 is the control center of the wireless power transmission device 100, and includes a processor and a memory. The processor operates according to these software and control data to perform various functions.

Specifically, the control circuit 170 controls the output of the inverter circuit 120 in cooperation with the charge monitoring circuit 230 on the power receiving side, which will be described later. The output of the inverter circuit 120 is controlled by the gate drive circuit 140 based on the transmission current S002, the reception voltage S003 received by the transmission-side communication circuit 150 from the wireless power reception device 200, the parameter 160a stored in the storage unit 160, and the like. give instructions.

The power transmission pad 100b includes a magnetic field coupling resonance circuit including a coil L1 and a capacitor C1, and is magnetically coupled to the power reception pad 200b by electromagnetic induction to wirelessly transmit power. In this embodiment, a case where a magnetic field coupling resonance circuit is used will be described as an example, but electric field coupling type power transmission pads and power reception pads may be used.

As described above, the wireless power receiving device 200 includes the power receiving unit 200a and the power receiving pad 200b.
The power receiving pad 200b includes a magnetic field coupling resonance circuit including a coil L2 and a capacitor C2, and is magnetically coupled to the power transmitting pad 100b by electromagnetic induction to wirelessly receive power. When the electric field coupling type resonance circuit is used for the power transmission pad 100b, a resonance circuit suitable for it may be provided to receive power.

The power receiving unit 200 a includes a rectifying circuit 210 , a power receiving side sensor circuit 220 , a charge monitoring circuit 230 , and a power receiving side communication circuit 240 .

The rectifier circuit 210 rectifies the AC voltage received by the power receiving unit 200a, converts it into a DC voltage, and outputs the received current to the power-supplied device 300 in the subsequent stage.

The power receiving side sensor circuit 220 detects the value of the voltage (the voltage of the secondary battery 300a) applied from the power receiving unit 200a to the secondary battery 300a as a power receiving voltage S003 and outputs it to the charge monitoring circuit 230. FIG.

The charge monitoring circuit 230 is the control center of the wireless power receiving device 200, and includes a processor and memory. .

Specifically, the charge monitoring circuit 230 cooperates with the control circuit 170 on the power transmission side to control charging (power supply) to the power-supplied device 300 . It responds and provides information to the control circuit 170 on the power transmission side for charging according to a value (for example, a target voltage value, etc.) and control related to this charging.

The power reception side communication circuit 240 communicates with the power transmission side communication circuit 150 described above, and transmits information notified from the charge monitoring circuit 230 to the power transmission side communication circuit 150, or transmits information from the power transmission side communication circuit 150. It notifies the charge monitoring circuit 230 of the received information.

Host device 400 has a function of receiving an instruction from an operator, giving the instruction to charge monitoring circuit 230, or notifying (for example, displaying) information provided from charge monitoring circuit 230 to the operator.

Next, with reference to FIG. 5, an outline of charging power control of the wireless power transmission system will be described.
First, in the wireless power receiving device 200, the charge monitoring circuit 230 receives a power receiving current value command as a power receiving side current command value as an initial setting from the operator through the host device 400 before the power receiving operation.

Then, when an instruction to start power reception is received, the charge monitoring circuit 230 transmits the power receiving voltage S003 detected by the power receiving side sensor circuit 220 and the power receiving side current command value to the wireless power transmission device 100 through the power receiving side communication circuit 240. .

On the other hand, in the wireless power transmission device 100, the control circuit 170 multiplies the power reception voltage S003 received by the power transmission side communication circuit 150 by the power reception side current command value, and the storage unit 160 stores the result of this multiplication. is multiplied by the parameter 160a as an efficiency correction coefficient to generate a power transmission command value.

Then, the control circuit 170 multiplies the transmission voltage S001 detected by the power transmission side sensor circuit 130 and the transmission current S002 to generate a transmission power response value. Then, the control circuit 170 subtracts the transmitted power response value from the transmitted power command value.

The control circuit 170 uses the result of the above subtraction for PID control (proportional-integral-derivative control) for timing control for switching the gate of the inverter circuit 120 through the gate drive circuit 140 . That is, the timing control is performed so that the result of the subtraction becomes a desired value.

Note that the multiplication of the power receiving voltage S003 and the power receiving side current command value may be performed on the wireless power receiving apparatus 200 side. That is, the charge monitoring circuit 230 may notify the wireless power transmission device 100 of the multiplication result of the power receiving voltage S003 and the power receiving side current command value.

Next, with reference to FIG. 6, detailed operation of charging power control of the wireless power transmission system will be described. FIG. 6 shows the power transmitting side charging process by the wireless power transmission device 100 and the power receiving side charging process by the wireless power receiving device 200 in association with each other, showing cooperation between the two.

First, the flowchart of the power transmission side charging process by the wireless power transmission device 100 will be described. This processing is performed by the control circuit 170 .

In step S101, the control circuit 170 performs preprocessing, and proceeds to step S102. As the preprocessing, the parameters 160a stored in advance in the storage unit 160 are read, and predetermined initial settings (for example, setting of the charging start voltage range, the charging end voltage, and the charging range voltage range) are performed.

In step S102, the control circuit 170 starts waiting for notification from the power transmission side communication circuit 150, and proceeds to step S103. Along with this, the power transmission side communication circuit 150 establishes a communication link with the wireless power receiving device 200 (the power receiving side communication circuit 240), enters a standby state for receiving information transmitted from the wireless power receiving device 200, and transmits the information. Start receiving information.

In step S103, the control circuit 170 determines whether or not the power transmission side communication circuit 150 has received a charge permission signal from the wireless power receiving device 200 (power receiving side communication circuit 240). Here, when the power transmission side communication circuit 150 receives the charging permission signal, the process proceeds to step S104.

After transmitting the charging permission signal, wireless power receiving device 200 (power receiving side communication circuit 240) transmits the value of power receiving voltage S003 and the power receiving side current command value. Received by

In step S<b>104 , the control circuit 170 determines whether the value of the power reception voltage is within or outside the charging start voltage range based on the power reception voltage information received from the power transmission side communication circuit 150 .

Here, if the value of the power reception voltage is within the range of the charging start voltage, the process proceeds to step S105. The reception of the charge permission signal is monitored again.

In step S105, the control circuit 170 instructs the power transmission side communication circuit 150 to transmit a charging start signal indicating the start of wireless power transmission for charging, and proceeds to step S106. In response to this, the power transmission side communication circuit 150 transmits a charging start signal to the wireless power receiving device 200 (power receiving side communication circuit 240).

In step S106, the control circuit 170 multiplies the power receiving voltage S003 received in step S104 by the power receiving side current command value, multiplies the multiplication result by the parameter 160a read in step S101 as an efficiency correction coefficient, and The result is determined as the transmission power command value, and the process proceeds to step S107.

In step S107, the control circuit 170 starts the charging process, and proceeds to step S108. In addition, in the charging process, the power transmission side sensor circuit 130 detects the power transmission voltage S001 and the power transmission current S002, and multiplies them to generate a power transmission response value. Then, the control circuit 170 subtracts the transmitted power response value from the transmitted power command value determined in step S106.

The control circuit 170 uses the result of this subtraction for PID control (proportional-integral-derivative control) for timing control for switching the gate of the inverter circuit 120 through the gate drive circuit 140 . As a result, an AC voltage corresponding to the received power voltage S003 is output from the inverter circuit 120, and wireless power transmission is started from the power transmission pad 100b.

In step S<b>108 , the control circuit 170 determines whether the value of the power reception voltage S<b>003 has reached the charging end voltage based on the value of the power reception voltage S<b>003 received by the power transmission side communication circuit 150 . Here, when the value of the power reception voltage reaches the charge end voltage, the process proceeds to step S110, and when the value of the power reception voltage is within the charge range voltage, the process proceeds to step S109.

In step S109, the control circuit 170 determines whether or not the power transmission side communication circuit 150 has received a charge permission signal from the wireless power receiving device 200 (power receiving side communication circuit 240). Here, when the power transmission side communication circuit 150 receives the charging permission signal, the process proceeds to step S108 to continue the charging process, and when not received, the process proceeds to step S110.

In step S110, the control circuit 170 stops the charging process started in step S107, proceeds to step S102, and waits for reception of the charging permission signal.

Next, a flowchart of power receiving side charging processing by the wireless power receiving device 200 will be described. This processing is performed by the charge monitoring circuit 230 .

In step S201, the charge monitoring circuit 230 performs preprocessing, and proceeds to step S202. As the preprocessing, predetermined initial settings are performed.

In step S202, the charging monitoring circuit 230 starts waiting for notification of permission to charge from the host device 400, and proceeds to step S203.

In step S<b>203 , the charge monitoring circuit 230 determines whether or not a charge permission signal has been received from the host device 400 . Here, when the charge monitoring circuit 230 receives the charge permission signal, the process proceeds to step S204. to monitor. The charge permission signal from host device 400 is continuously given from host device 400 while charging is permitted.

In step S204, the charge monitoring circuit 230 instructs the power receiving side communication circuit 240 to transmit a charge permission signal, and proceeds to step S205. In response to this, the power receiving side communication circuit 240 transmits a charging permission signal to the wireless power transmission device 100 (power transmitting side communication circuit 150) as processing corresponding to step S103 described above.

In step S205, the charge monitoring circuit 230 acquires the power receiving voltage S003 through the power receiving side sensor circuit 220, instructs the power receiving side communication circuit 240 to transmit the power receiving voltage S003, and proceeds to step S206. On the other hand, the power receiving side communication circuit 240 transmits the power receiving voltage S003 to the wireless power transmission device 100 (the power transmitting side communication circuit 150) as a process corresponding to the above-described step S104.

In step S206, the charging monitoring circuit 230 determines whether or not the power receiving side communication circuit 240 has received a charging start signal from the wireless power transmission device 100 (the power transmitting side communication circuit 150). Here, if the power receiving side communication circuit 240 receives the charge start signal, the process proceeds to step S207, and if not, the process proceeds to step S204 again to transmit the charge permission signal.

In step S207, the charge monitoring circuit 230 acquires the power receiving voltage S003 again through the power receiving side sensor circuit 220, instructs the power receiving side communication circuit 240 to transmit the power receiving voltage S003, and proceeds to step S208. In response to this, the power receiving side communication circuit 240 transmits the power receiving voltage S003 to the wireless power transmission device 100 (the power transmitting side communication circuit 150) as a process corresponding to step S108 described above.

In step S<b>208 , charge monitoring circuit 230 determines whether or not a charge permission signal has been received from higher-level device 400 . Here, if the charge monitoring circuit 230 receives the charge permission signal, the process proceeds to step S209, and if not, the process proceeds to step S210.

In step S209, the charge monitoring circuit 230 instructs the power receiving side communication circuit 240 to transmit a charge permission signal, and the process proceeds to step S207. In response to this, the power receiving side communication circuit 240 transmits a charging permission signal to the wireless power transmission device 100 (power transmitting side communication circuit 150) as processing corresponding to step S109 described above.

In step S<b>210 , the charge monitoring circuit 230 stops the charging process, proceeds to step S<b>202 , and waits for reception of the charge permission signal from the host device 400 again.

As described above, in the above wireless power transmission system, the wireless power transmission device 100 is notified of the voltage value (received voltage) applied to the secondary battery 300a of the wireless power receiving device 200, and the wireless power transmission device 100: The transmission power is controlled in accordance with the notified received power voltage.

As in the past, when the transmitted power is controlled to be constant, the power received by the power receiving side is also constant. In particular, when the secondary battery is charged on the power receiving side, the receiving current depends on the battery voltage. Therefore, as shown in FIG. 7, when the battery voltage is low, the receiving current increases. For this reason, when charging a secondary battery whose battery voltage fluctuates in a wide range, it has been necessary to set a large component rating for the power receiving side component. In the simulation of FIG. 7, it is about 180A.

On the other hand, in the above-described wireless power transmission system, as described above, the transmitted power is controlled according to the received voltage of the secondary battery 300a. change can be suppressed. In other words, it is no longer necessary to set a large component rating for the power receiving side component. In the simulation of FIG. 8, it is 120 A or less.

It should be noted that the present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying constituent elements without departing from the scope of the present invention at the implementation stage. Further, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the above embodiments. Further, for example, a configuration in which some components are deleted from all the components shown in the embodiments is also conceivable. Furthermore, components described in different embodiments may be combined as appropriate.

For example, in the power transmission side charging process shown in FIG. 6, the charging process in step S107 is described as performing power transmission based on the power transmission command value determined in step S106 based on the power reception voltage received in step S104. It is not limited to this. For example, as shown in FIG. 9, step S111 may be added to update the power transmission command value.

Specifically, in step S111, the control circuit 170 multiplies the power receiving voltage S003 received in step S108 by the power receiving side current command value, and multiplies the multiplication result by the parameter 160a read in step S101 as an efficiency correction coefficient. Then, the multiplication result is determined as the transmission power command value.
In this way, by updating the power transmission command value according to the latest received voltage S003 during the charging process, it is possible to control the received current to be constant without being affected by fluctuations in the battery voltage.

In addition, it goes without saying that various modifications can be made in the same way without departing from the scope of the present invention.

DESCRIPTION OF SYMBOLS 100... Wireless power transmission apparatus 100a... Power transmission unit 100b... Power transmission pad 110... Single-phase (or three-phase) rectifier 120... Inverter circuit 130... Power transmission side sensor circuit 140... Gate drive circuit 150... Power transmission side Communication circuit 160 Storage unit 160a Parameter 170 Control circuit 200 Wireless power receiving device 200a Power receiving unit 200b Power receiving pad 210 Rectifier circuit 220 Power receiving side sensor circuit 230 Charge monitoring circuit , 240... Power receiving side communication circuit 300... Powered device 300a... Secondary battery 300b... Motor drive circuit 300c... Motor 400... Host device.

Claims (6)

In a wireless power transmission device that wirelessly transmits power,
a communication unit that receives information on the voltage of a secondary battery that is charged by wirelessly transmitted power;
a control unit that controls power to be transmitted based on the information received by the communication unit;
A wireless power transmission device comprising: The wireless power transmission device according to claim 1, wherein the control unit obtains a target value based on the information received by the communication unit and a preset correction coefficient, and controls power to be transmitted so as to match the target value. a voltage detection unit that detects the value of the transmission voltage;
A current detection unit that detects the value of the transmission current,
The wireless power transmission device according to claim 2, wherein the control section controls power to be transmitted so that a value obtained by multiplying the detection value of the voltage detection section and the detection value of the current detection section becomes the target value. In a wireless power transmission system that wirelessly transmits power from a power transmitting device to a power receiving device,
The power receiving device,
a battery voltage detection unit that detects the voltage of a secondary battery that is charged by wirelessly transmitted power;
a transmission unit that transmits information on the voltage detected by the battery voltage detection unit to the power transmission side device;
with
The power transmission side device,
a receiving unit that receives information about the voltage of the secondary battery;
a control unit that controls power to be transmitted based on the information received by the receiving unit;
A wireless power transfer system comprising: The power transmission side device further
a voltage detection unit that detects the value of the transmission voltage;
A current detection unit that detects the value of the transmission current,
The transmission unit transmits information on the voltage detected by the battery voltage detection unit and information on a command value indicating a current given from a host device to the power transmission side device,
The receiving unit receives information on the voltage of the secondary battery and information on the command value,
The control unit multiplies a value obtained by multiplying the detection value of the voltage detection unit and the detection value of the current detection unit, and a multiplication value of the voltage of the secondary battery based on the information received by the reception unit and the command value. The wireless power transmission system according to Claim 4, wherein the power to be transmitted is controlled based on the comparison result. The power transmission side device further
a voltage detection unit that detects the value of the transmission voltage;
A current detection unit that detects the value of the transmission current,
The transmission unit transmits information on the voltage detected by the battery voltage detection unit,
The receiving unit receives information on the voltage of the secondary battery,
The control unit outputs a command indicating a value obtained by multiplying the detection value of the voltage detection unit by the detection value of the current detection unit, the voltage of the secondary battery based on the information received by the reception unit, and the prerecorded current. 5. The wireless power transmission system according to claim 4, wherein the power to be transmitted is controlled based on a result of comparing the value information with the multiplied value of the power transmitting device.

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