KR102443355B1 - Wireless power transmission and charging system - Google Patents

Abstract

A wireless power transmission and charging system is disclosed. A charging state determination method of a wireless power transmitter includes estimating a transmit power value based on a control error value (CEV) periodically received from a wireless power receiver in a power transfer step, and the transmit power value is If it is maintained without fluctuation for more than a preset time, determining that it has entered a Normal Stable State (NSS), and based on the control error value received after entering the NSS, the width of the increase in the transmit power value and determining the current charging state as a 'foreign matter generation state' or a 'load change state' when the rising width of the transmission power value exceeds a preset threshold value.

Description

WIRELESS POWER TRANSMISSION AND CHARGING SYSTEM

The technical field relates to power control of a wireless power transmission system for wirelessly transmitting and receiving power.

The wireless power transmission system includes a wireless power transmitter for wirelessly transmitting electrical energy and a wireless power receiver for receiving electrical energy from the wireless power transmitter. The wireless power transfer system may be applied to a local computing environment.

Using a wireless power transfer system, for example, it is possible to charge the battery of a mobile phone by simply placing the mobile phone on a charging pad without connecting the mobile phone to a separate charging connector.

A method of wirelessly transmitting electrical energy may be classified into a magnetic induction method, a magnetic resonance method, and an electromagnetic wave method according to a principle of transmitting electrical energy.

The magnetic induction method is a method of transferring electrical energy by using a phenomenon in which electricity is induced between a transmitter coil and a receiver coil.

The magnetic resonance method is a method in which a magnetic field that vibrates at a resonant frequency is generated in a coil of a transmitter, and energy is intensively transferred to a coil of a receiver designed with the same resonant frequency.

The electromagnetic wave method is a method in which the electromagnetic wave generated by the transmitter is received by the receiver using several rectennas and converted into electrical energy.

On the other hand, the wireless power transfer technology is a wireless power transfer technology that is flexibly coupled according to the form or strength of magnetic resonant coupling between the transmitter coil and the receiver coil (hereinafter 'flexibly coupled technology') and tightly coupled wireless power transfer technology (hereinafter, 'tightly coupled technology') may be distinguished.

At this time, in the case of 'flexibly coupled technology', since a magnetic resonance coupling may be formed between one transmitter resonator and a plurality of receiver resonators, concurrent multiple charging may be possible.

In this case, the 'tightly coupled technology' may be a technology capable of only one-to-one power transmission between one transmitter coil and one receiver coil.

As an example of applying such a wireless power transmission and charging system to a wireless power transmission network such as a local computing environment, prior art 3 and prior art 5 described in "Prior Art Documents" are disclosed.

However, prior art 3 and prior art 5 also do not provide a clear method for power control.

Prior art 1: Korean Patent Application Laid-Open No. 2014-0057503 (2014.05.13), titled "Wireless power receiver and power control method thereof" Prior art 2: Korean Patent Application Laid-Open No. 2014-0061337 (2014.05.13), titled "Wireless Power Transmission Apparatus and Wireless Power Transmission Method"

To present a wireless power transmission and charging system, and to present an improved configuration of the wireless power transmission and charging system.

A method for determining a state of charge of a wireless power transmitter according to an embodiment includes: estimating a transmission power value based on a control error value (CEV) periodically received from a wireless power receiver in the power transmission step; , when the transmission power value is maintained without fluctuation for more than a preset time, determining that it has entered a Normal Stable State (NSS), and the transmission based on a control error value received after entering the NSS Monitoring the rise width of the power value, and when the rise width of the transmission power value exceeds a preset threshold, determining the current charging state as a 'foreign substance generation state' or a 'load change state'.

In the method for determining the state of charge of the wireless power transmitter according to another embodiment, a control error value (CEV) periodically received from the wireless power receiver in the power transmission step is equal to or greater than a preset number of times or less than a preset stabilization reference value. is maintained, determining that it has entered a normal stable state (NSS), monitoring the rise width of the control error value received after entering the NSS, and receiving after entering the NSS and determining the current charging state as a 'foreign matter generation state' or a 'load change state' when the rise width of the control error value exceeds the stabilization reference value.

A wireless power transmission apparatus according to an embodiment includes a transmission power value estimator for estimating a transmission power value based on a control error value (CEV) periodically received from the wireless power reception apparatus in a power transmission step; If the transmit power value is maintained without fluctuation for more than a preset time, a determination unit that determines that it has entered a Normal Stable State (NSS), and when the rise width of the transmit power value exceeds a preset threshold, the current and a state of charge determination unit that determines the state of charge as a 'foreign matter generation state' or a 'load change state'.

According to an embodiment of the present invention, stable and efficient wireless power transmission and charging is possible.

The wireless power transmitter may estimate the current transmit power value without additional configuration or measurement and determine the foreign matter detection state.

1 is a diagram for explaining the overall concept of a wireless power transmission system.
2 is a block diagram of a wireless power transmitter and a wireless power receiver according to an embodiment of the present invention.
3 is a detailed block diagram of a wireless power transmitter and a wireless power receiver according to an embodiment of the present invention.
4 is a flowchart illustrating operations of a wireless power transmitter and a wireless power receiver according to an embodiment of the present invention.
5 is a flowchart illustrating operations of a wireless power transmitter and a wireless power receiver according to another embodiment of the present invention.
FIG. 6 is a graph on the time axis of the amount of power applied by the wireless power transmitter according to the embodiment of FIG. 5 .
7 is a block diagram of a wireless power transmitter and a wireless power receiver according to another embodiment of the present invention.
8 is a diagram illustrating an example of configuring two primary coils.
9 is a diagram illustrating an example of configuring three primary coils.
10 is a detailed block diagram of a power transmitter for the wireless power transmitter according to the embodiment of FIG. 7 .
11 is a diagram illustrating an example of configuring a primary coil array for a power transmitter.
12 is a flowchart illustrating a control operation of a wireless power transmitter.
13 is a diagram for explaining a configuration of a power transmitter according to an embodiment.
14 is a diagram illustrating an example of a connection relationship between an output terminal of an inverter included in the power converter of FIG. 13 and a magnetic induction transmitter and a magnetic resonance transmitter.
FIG. 15 shows a configuration example of the magnetic induction transmitter and the magnetic resonance transmitter of FIG. 13 .
FIG. 16 is a view for explaining a method of controlling the primary coil array of FIG. 11 according to an exemplary embodiment.
17 is a diagram for explaining a power transfer control algorithm of a wireless power transmitter.
18 shows a configuration of a wireless power transmitter according to an embodiment.
19 illustrates a method for determining a charging state of a wireless power transmitter according to an embodiment.
20 to 24 are exemplary views for explaining various cases for determining the state of charge.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a diagram for explaining the overall concept of a wireless power transmission system.

Referring to FIG. 1 , the wireless charging system wirelessly transmits power 1-1, 1-2, and power to a wireless power transmitter 100 and at least one wireless power receiver 110-1, 110-2, and 110-n, respectively. 1-n) can be transmitted. More specifically, the wireless power transmitter 100 may wirelessly transmit power 1-1, 1-2, and 1-n only to an authenticated wireless power receiver that has performed a predetermined authentication procedure.

The wireless power transmitter 100 may form an electrical connection with the wireless power receivers 110-1, 110-2, and 110-n. For example, the wireless power transmitter 100 may transmit wireless power in the form of electromagnetic waves to the wireless power receivers 110-1, 110-2, and 110-n.

Also, the wireless power transmitter 100 may perform two-way communication with the wireless power receivers 110-1, 110-2, and 110-n. At this time, the wireless power transmitter 100 and the wireless power receivers 110-1, 110-2, and 110-n process or transmit/receive packets 2-1, 2-2, and 2-n composed of a predetermined frame. can do. The above-described frame will be described later in more detail. In particular, the wireless power receiver may be implemented as a mobile communication terminal, PDA, PMP, smart phone, or the like.

Also, the wireless power transmitter 100 may wirelessly provide power to the plurality of wireless power receivers 110-1, 110-2, and 110-n. For example, the wireless power transmitter 100 may transmit power to the plurality of wireless power receivers 110-1, 110-2, and 110-n through a resonance method. When the wireless power transmitter 100 adopts the resonance method, the distance between the wireless power transmitter 100 and the plurality of wireless power receivers 110 - 1 , 110 - 2 and 1110 - n may be preferably 30 m or less. In addition, when the wireless power transmitter 100 adopts the electromagnetic induction method, the distance between the wireless power transmitter 100 and the plurality of wireless power receivers 110-1, 110-2, 110-n may be preferably 10 cm or less. .

Also, the wireless power transmitter 100 may include a display means such as a display, and based on a message received from each of the wireless power receivers 110-1, 110-2, and 110-n, the wireless power receiver 110- 1,110-2,110-n) Each state can be displayed. In addition, the wireless power transmitter 100 may also display the estimated time until each of the wireless power receivers 110-1, 110-2, and 110-n is fully charged.

Also, the wireless power transmitter 100 may transmit a control signal for disabling the wireless charging function to each of the wireless power receivers 110-1, 110-2, and 110-n. The wireless power receiver that receives the disable control signal of the wireless charging function from the wireless power transmitter 100 may disable the wireless charging function.

The wireless power receivers 110-1, 110-2, and 110-n may receive wireless power from the wireless power transmitter 100 and charge a battery provided therein. In addition, the wireless power receivers 110-1, 110-2, and 110-n transmit a signal for requesting wireless power transmission, information necessary for wireless power reception, wireless power receiver status information or wireless power transmitter 100 control information, etc. to the wireless power transmitter ( 100) can be sent. Information on the transmission signal will be described later in more detail.

In addition, the wireless power receivers 110 - 1 , 110 - 2 , and 110 - n may transmit messages indicating respective charging states to the wireless power transmitter 100 .

2 is a block diagram of a wireless power transmitter and a wireless power receiver according to an embodiment of the present invention.

Referring to FIG. 2 , the wireless power transmitter 200 may include a power transmitter 211 , a controller 212 , and a communicator 213 . Also, the wireless power receiver 250 may include a power receiver 251 , a controller 252 , and a communicator 253 .

The power transmitter 211 may provide power required by the wireless power transmitter 200 and wirelessly provide power to the wireless power receiver 250 . Here, the power transmitter 211 may supply power in the form of an AC waveform, or convert it into an AC waveform using an inverter while supplying power in the form of a DC waveform and supply it in the form of an AC waveform. The power transmitter 211 may be implemented in the form of a built-in battery, or may be implemented in the form of a power reception interface to receive power from the outside and supply it to other components. Those skilled in the art will readily understand that the power transmitter 211 is not limited as long as it is a means capable of providing power of a constant AC waveform.

In addition, the power transmitter 211 may provide the AC waveform in the form of electromagnetic waves to the wireless power receiver 250 . The power transmitter 211 may further include a loop coil, and thus may transmit or receive a predetermined electromagnetic wave. When the power transmitter 211 is implemented as a loop coil, the inductance L of the loop coil may be changeable. Meanwhile, those skilled in the art will readily understand that the power transmitter 211 is not limited as long as it is a means capable of transmitting and receiving electromagnetic waves.

The controller 212 may control overall operations of the wireless power transmitter 200 . The controller 212 may control the overall operation of the wireless power transmitter 200 using an algorithm, program, or application required for control read from a storage unit (not shown). The controller 212 may be implemented in the form of a CPU, a microprocessor, or a mini computer. A detailed operation of the control unit 212 will be described later in more detail.

The communication unit 213 may communicate with the wireless power receiver 250 in a predetermined manner. The communication unit 213 may perform communication with the communication unit 253 of the wireless power receiver 250 using Near Field Communication (NFC), Zigbee communication, infrared communication, visible light communication, or the like. The communication unit 213 according to an embodiment of the present invention may perform communication using the IEEE802.15.4 Zigbee communication method. In addition, the communication unit 213 may use a CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance) algorithm. The configuration related to the frequency and channel selection used by the communication unit 213 will be described later in more detail. Meanwhile, the above-described communication method is merely exemplary, and the scope of the present invention is not limited by the specific communication method performed by the communication unit 213 .

Meanwhile, the communication unit 213 may transmit a signal for information of the wireless power transmitter 200 . Here, the communication unit 213 may unicast, multicast, or broadcast a signal.

The communication unit 213 may receive power information from the wireless power receiver 250 . Here, the power information may include at least one of a capacity of the wireless power receiver 250 , a battery remaining amount, the number of times of charging, a usage amount, a battery capacity, and a battery ratio. Also, the communication unit 213 may transmit a charging function control signal for controlling the charging function of the wireless power receiver 250 . The charging function control signal may be a control signal for controlling the wireless power receiver 251 of the specific wireless power receiver 250 to enable or disable the charging function.

Also, the communication unit 213 may receive a signal from the wireless power receiver 250 as well as another wireless power transmitter (not shown). For example, the communication unit 213 may receive a notice signal of a frame from another wireless power transmitter.

Meanwhile, in FIG. 2 , although the power transmitter 211 and the communication unit 213 are configured with different hardware and the wireless power transmitter 200 communicates in an out-band format, this is exemplary. In the present invention, the power transmitter 211 and the communication unit 213 are implemented as one piece of hardware, so that the wireless power transmitter 200 can communicate in an in-band format.

The wireless power transmitter 200 and the wireless power receiver 250 may transmit/receive various signals, and accordingly, subscription of the wireless power receiver 250 to the wireless power network controlled by the wireless power transmitter 200 and wireless power transmission/reception A charging process may be performed through , and the above-described process will be described later in more detail.

In addition, although the configuration of the wireless power transmitter 200 and the wireless power receiver 250 is briefly illustrated in FIG. 2 , the detailed configuration of the wireless power transmitter 200 and the wireless power receiver 250 is illustrated in FIG. 3 , , a detailed description thereof will be described later.

3 is a detailed block diagram of a wireless power transmitter and a wireless power receiver according to an embodiment of the present invention.

Referring to FIG. 3 , the wireless power transmitter 200 may include a power transmitter 211 , a controller and communication units 212 and 213 , a driving unit 214 , an amplifier 215 , and a matching unit 216 . The wireless power receiver 250 may include a power receiver 251 , control and communication units 252 and 253 , a rectifier 254 , a DC/DC converter 255 , a switch unit 256 , and a load unit 257 . .

The driving unit 214 may output DC power having a preset voltage value. The voltage value of the DC power output from the driving unit 214 may be controlled by the control unit and the communication units 212 and 213 .

The direct current output from the driving unit 214 may be output to the amplifying unit 215 . The amplifying unit 215 may amplify the DC current with a preset gain. In addition, DC power may be converted into AC based on signals input from the control unit and the communication units 212 and 213 . Accordingly, the amplifier 215 may output AC power.

The matching unit 216 may perform impedance matching. For example, by adjusting the impedance viewed from the matching unit 216, it is possible to control the output power to be high efficiency or high output. The matching unit 216 may adjust the impedance based on the control of the controller and the communication units 212 and 213 . The matching unit 216 may include at least one of a coil and a capacitor. The controller and communication units 212 and 213 may control a connection state with at least one of a coil and a capacitor, and thus may perform impedance matching.

The power transmitter 211 may transmit the input AC power to the power receiver 251 . The power transmitter 211 and the power receiver 251 may be implemented as resonant circuits having the same resonant frequency. For example, the resonance frequency may be determined to be 6.78 MHz. The control unit and communication units 212 and 213 may communicate with the control unit and communication units 252 and 253 on the wireless power receiver 250 side.

Meanwhile, the power receiver 251 may receive charging power from the power transmitter 211 .

The rectifier 254 may rectify the wireless power received by the power receiver 251 in a DC form, and may be implemented in the form of, for example, a bridge diode. The DC/DC converter unit 255 may convert the rectified power to a preset gain. For example, the DC/DC converter unit 255 may convert the rectified power so that the voltage of the output terminal 259 becomes 5V. Meanwhile, a minimum value and a maximum value of a voltage that can be applied to the front end 258 of the DC/DC converter unit 255 may be preset.

The switch unit 256 may connect the DC/DC converter unit 255 and the load unit 257 to each other. The switch unit 256 may maintain an on/off state under the control of the controller 252 . The load unit 257 may store the converted power input from the DC/DC converter unit 255 when the switch unit 256 is in an on state.

4 is a flowchart illustrating operations of a wireless power transmitter and a wireless power receiver according to an embodiment of the present invention.

Referring to FIG. 4 , the wireless power transmitter 400 may apply power ( S401 ). When power is applied, the wireless power transmitter 400 may configure an environment (S402).

The wireless power transmitter 400 may enter a power save mode (S403). In the power saving mode, the wireless power transmitter 400 may apply power beacons 404 and 405 for heterogeneous detection at each cycle. For example, as shown in FIG. 4 , the wireless power transmitter 400 may apply a power beacon for detection, and the power value of each of the detection power beacons 404 and 405 may be different. Some or all of the detection power beacons 404 and 405 may have an amount of power capable of driving the communication unit of the wireless power receiver 450 and an application time. For example, the wireless power receiver 450 may communicate with the wireless power transmitter 400 by driving a communication unit by some or all of the detection power beacons 404 and 405 . The state may be referred to as a null state.

The wireless power transmitter 400 may detect a load change due to the arrangement of the wireless power receiver 450 . The wireless power transmitter 400 may enter a low power mode ( S409 ). The low power mode may be a mode in which the wireless power transmitter periodically or aperiodically applies the detection power. Meanwhile, the wireless power receiver 450 may drive the communication unit based on the power received from the wireless power transmitter 400 ( S409 ).

The wireless power receiver 450 may transmit a Power Transmitter Unit (PTU) search signal to the wireless power transmitter 400 (S410). The wireless power receiver 450 may transmit a PTU search signal as a BLE-based advertisement signal. The wireless power receiver 450 may transmit a PTU search signal periodically or aperiodically, and receive a Power Receiver Unit (PRU) response signal from the wireless power transmitter 400, or when a preset time arrives. can be sent until

When the PTU search signal is received from the wireless power receiver 450, the wireless power transmitter 400 may transmit a PRU response signal (S411). Here, the PRU response signal may establish a connection between the wireless power transmitter 400 and the wireless power receiver 450 .

The wireless power receiver 450 may transmit a PRU static signal (S412). Here, the PRU static signal may be a signal indicating the state of the wireless power receiver 450 , and may request to join the wireless power network controlled by the wireless power transmitter 400 .

The wireless power transmitter 400 may transmit a PTU static signal (S413). The PTU static signal transmitted by the wireless power transmitter 400 may be a signal indicating the capability of the wireless power transmitter 400 .

When the wireless power transmitter 400 and the wireless power receiver 450 transmit and receive a PRU static signal and a PTU static signal, the wireless power receiver 450 may periodically transmit a PRU dynamic signal (S414, S415).

The PRU dynamic signal may include at least one parameter information measured by the wireless power receiver 450 . For example, the PRU dynamic signal may include voltage information at the rear end of the rectifier of the wireless power receiver 450 . The state of the wireless power receiver 450 may be referred to as a boot state.

The wireless power transmitter 400 enters the power transmission mode (S416), and the wireless power transmitter 400 may transmit a PRU command signal, which is a command signal for the wireless power receiver 450 to perform charging. (S417). In the power transmission mode, the wireless power transmitter 400 may transmit charging power.

The PRU command signal transmitted by the wireless power transmitter 400 may include information for enabling/disabling charging of the wireless power receiver 450 and permission information. The PRU command signal may be transmitted when the wireless power transmitter 400 changes the state of the wireless power receiver 450 or may be transmitted at a preset period (eg, a period of 250 ms). The wireless power receiver 400 may change a setting according to the PRU command signal and transmit a PRU dynamic signal for reporting the state of the wireless power receiver 450 ( S418 and S419 ). The PRU dynamic signal transmitted by the wireless power receiver 450 may include at least one of voltage, current, wireless power receiver state and temperature information. The state of the wireless power receiver 450 may be called an On state.

The wireless power receiver 450 may receive the PRU command signal to perform charging. For example, the wireless power transmitter 400 enables charging when the wireless power transmitter 400 has sufficient power to charge the wireless power receiver 450 . It can transmit a PRU command signal to do so. On the other hand, the PRU command signal may be transmitted whenever the state of charge is changed. The PRU command signal may be transmitted, for example, every 250 ms, or may be transmitted when there is a parameter change. The PRU command signal may be configured to be transmitted within a preset threshold time (eg, within 1 second) even if the parameter is not changed.

Meanwhile, the wireless power receiver 450 may detect the occurrence of an error. The wireless power receiver 450 may transmit a warning signal to the wireless power transmitter 400 (S420). The warning signal may be transmitted as a PRU dynamic signal or may be transmitted as a PRU warning signal. For example, the wireless power receiver 450 may transmit an error condition to the PRU warning information field of Table 4 to the wireless power transmitter 400 . Alternatively, the wireless power receiver 450 may transmit a single warning signal indicating an error condition to the wireless power transmitter 400 . When the wireless power transmitter 400 receives the PRU warning signal, it may enter a latch failure mode (S422). The wireless power receiver 450 may enter a null state (S423).

5 is a flowchart illustrating operations of a wireless power transmitter and a wireless power receiver according to another embodiment of the present invention.

The control method of FIG. 5 will be described in more detail with reference to FIG. 6 . FIG. 6 is a graph on the time axis of the amount of power applied by the wireless power transmitter according to the embodiment of FIG. 5 .

Referring to FIG. 5 , the wireless power transmitter may start driving ( S501 ). In addition, the wireless power transmitter may reset initial settings (S503). The wireless power transmitter may enter a power saving mode (S505). Here, the power saving mode may be a section in which the wireless power transmitter applies different types of power having different amounts of power to the power transmitter. For example, the wireless power transmitter may be a section in which the second detection power 601 and 602 and the third detection power 611 , 612 , 613 , 614 , and 615 are applied to the power transmitter in FIG. 6 . Here, the wireless power transmitter may periodically apply the second detection powers 601 and 602 in a second period, and when applying the second detection powers 601 and 602, may apply it during the second period.

The wireless power transmitter may periodically apply the third detection power 611 , 612 , 613 , 614 , and 615 at a third period, and when the third detection power 611 , 612 , 613 , 614 , and 615 is applied, It may be authorized for a third period. Meanwhile, the respective power values of the third detection powers 611 , 612 , 613 , 614 and 615 are shown as different, but the respective power values of the third detection powers 611 , 612 , 613 , 614 , 615 are different may be, or may be the same.

After outputting the third detection power 611 , the wireless power transmitter may output the third detection power 612 having the same amount of power. As described above, when the wireless power transmitter outputs the third detection power of the same size, the amount of power of the third detection power has an amount of power capable of detecting the smallest wireless power receiver, for example, a category 1 wireless power receiver. can

After outputting the third detection power 611 , the wireless power transmitter may output the third detection power 612 having an upper limit amount of power. When the wireless power transmitter outputs third detection power of different magnitudes, each of the third detection power amounts may be an amount of power capable of detecting category 1 to 5 wireless power receivers. For example, the third detection power 611 may have an amount of power capable of detecting a category 5 wireless power receiver, and the third detection power 612 may have an amount of power capable of detecting a category 3 wireless power receiver. may have, and the third detection power 613 may have an amount of power capable of detecting the category 1 wireless power receiver.

Meanwhile, the second detection power 601 and 602 may be power capable of driving the wireless power receiver. More specifically, the second detection power 601 and 602 may have an amount of power capable of driving the control unit and the communication unit of the wireless power receiver.

The wireless power transmitter may apply the second detection powers 601 and 602 and the third detection powers 611 , 612 , 613 , 614 , and 615 to the power receiver at second and third cycles, respectively. When the wireless power receiver is disposed on the wireless power transmitter, the impedance viewed from one point of the wireless power transmitter may be changed. The wireless power transmitter may detect an impedance change while the second detection powers 601 and 602 and the third detection powers 611 , 612 , 613 , 614 , and 615 are applied. For example, the wireless power transmitter may detect a change in impedance while applying the third detection power 615 . Accordingly, the wireless power transmitter may detect the object (S507). When no object is detected (S507-N), the wireless power transmitter may maintain a power saving mode in which different types of power are periodically applied (S505).

Meanwhile, when an object is detected due to a change in impedance (S507-Y), the wireless power transmitter may enter a low power mode. Here, the low power mode is a mode in which the wireless power transmitter applies driving power having an amount of power capable of driving the control unit and the communication unit of the wireless power receiver. For example, as shown in FIG. 6 , the wireless power transmitter may apply driving power 620 to the power transmitter. The wireless power receiver may receive the driving power 620 to drive the control unit and the communication unit. The wireless power receiver may communicate with the wireless power transmitter based on a predetermined method based on the driving power 620 . For example, the wireless power receiver may transmit/receive data required for authentication, and may subscribe to a wireless power network managed by the wireless power transmitter based thereon. However, when a foreign material other than the wireless power receiver is disposed, data transmission/reception cannot be performed. Accordingly, the wireless power transmitter may determine whether the disposed object is a foreign object ( S511 ). For example, when the wireless power transmitter does not receive a response from the object for a preset time, the wireless power transmitter may determine the object as a foreign material.

When it is determined as a foreign material (S511-Y), the wireless power transmitter may enter a latch failure mode. For example, the wireless power transmitter may periodically apply the first power 631 to 634 of FIG. 6 in a first period. The wireless power transmitter may detect an impedance change while applying the first power. For example, when the foreign material is recovered, the impedance change may be detected, and the wireless power transmitter may determine that the foreign material is recovered. Alternatively, when the foreign material is not recovered, the wireless power transmitter may not detect the impedance change, and the wireless power transmitter may determine that the foreign material is not recovered. When the foreign material is not collected, the wireless power transmitter may output at least one of a lamp and a warning sound to inform the user that the current state of the wireless power transmitter is an error state. Accordingly, the wireless power transmitter may include an output unit for outputting at least one of a lamp and a warning sound.

When it is determined that the foreign material is not recovered (S515-N), the wireless power transmitter may maintain the latch failure mode (S513). On the other hand, when it is determined that the foreign material is recovered (S515-Y), the wireless power transmitter may re-enter the power saving mode (S517). For example, the wireless power transmitter may apply the second power 651 and 652 and the third power 661 to 665 .

Meanwhile, in the case of FIGS. 5 and 6 , when the impedance change due to the arrangement of the wireless power receiver is not large, it may be difficult to detect the wireless power receiver.

7 is a block diagram of a wireless power transmitter and a wireless power receiver according to another embodiment of the present invention.

Referring to FIG. 7 , the wireless power transmitter 700 may include a system controller 710 and at least one power transmitter 720 and 730 , and the power transmitters 720 and 730 include power converters 721 and 731 . ) and communication and control units 723 and 733 . In addition, the wireless power receiver 750 may include a power receiver 751 and a load unit 755 , and the power receiver 751 may include a power pickup unit 752 and a communication and control unit 753 . .

The power converters 721 and 731 may convert electrical power into wireless power, and wirelessly transmit power to the power pickup unit 752 included in the receiver 752 of the at least one wireless power receiver 750 . The power converters 721 and 731 may include a primary coil of a magnetic induction method for wirelessly transmitting power.

The power pickup unit 752 may receive wireless power from the wireless power converters 721 and 731, convert the received wireless power into electrical power, and a magnetic induction secondary coil for receiving wireless power. (Secondary Coil) may be included. For example, the power converters 721 and 731 and the power pickup unit 752 may transmit and receive wireless power by maintaining the primary coil and the secondary coil in at least one of a horizontal alignment state and a vertical alignment state. . The primary coil may be a wire-wound type coil, may be a coil array including at least one coil, and may form a coreless resonant transformer part together with the secondary coil.

Meanwhile, the wireless power transmitter 700 may further include an interface surface (not shown) in the form of a flat surface to transmit wireless power. At least one wireless power receiver 750 may be placed on an upper portion of the interface surface, and a primary coil may be provided on a lower portion of the interface surface. At this time, a small vertical space is formed between the primary coil mounted on the lower part of the interface surface and the secondary coil of the wireless power receiver 750 positioned on the upper part of the interface surface, so that the primary coil and the secondary coil are separated. Inductive coupling may be achieved. Hereinafter, the primary coil will be described in detail.

8 is a diagram illustrating an example of configuring two primary coils, and FIG. 9 is a diagram illustrating an example of configuring three primary coils.

Referring to FIG. 8 , the two primary coils may be a winding type coil, and the winding type coil may be composed of 115 strands and a Litz Wire having a diameter of 0.08 mm. Also, the two primary coils may have a racetrack-like shape and may be configured as a single layer. In addition, the parameters of the two primary coils may include d _o and d _h , where d _o is an outer diameter of the primary coil, and d _h may be a distance between centers of the two primary coils.

Referring to FIG. 9 , the three primary coils may be composed of 105 strands and a litz wire having a diameter of 0.08 mm. In addition, the three primary coils may have a rectangular (Rectangular) shape, and may be composed of a single layer. In addition, the parameters of the three primary coils may include d _oe and d _oo , where d _oe is the distance between the center of the first primary coil and the center of the second primary coil, and d _oo is the first primary It may be a distance between the center of the coil and the center of the third primary coil.

Referring back to FIG. 7 , the communication and control units 723 and 733 may perform communication with at least one power receiver 752 . In addition, the communication and control units 723 and 733 may receive a request message for required wireless power from the power receiving unit 752 , and accordingly, the communication and control units 723 and 733 may receive the wireless power requested from the power receiving unit 752 . The power converter 721 may be controlled to transmit this.

The power pickup unit 752 may receive wireless power from the power converter 721 , and the load unit 755 may charge the battery by loading the received wireless power. The communication and control unit 753 may perform communication with the transmitters 720 and 730 and may control wireless power to be received from the transmitters 720 and 730 . Hereinafter, a detailed configuration of the power transmitters 720 and 730 will be described with reference to FIG. 10 .

10 is a detailed block diagram of a power transmitter for the wireless power transmitter according to the embodiment of FIG. 7 .

Referring to FIG. 10 , the power transmitters 720 and 730 may include a communication and control unit 721 and a power converter 723 , and the power converter 723 includes an inverter 723a and an impedance matching unit 723b. , a sensing unit 723c, a multiplexer 723d, and a primary coil array 723e may be included.

In the power conversion unit 723, the inverter 723a may convert a DC (Digital Current) input into an AC (Analog Current) waveform, and the impedance matching unit 723b includes a resonance circuit and a primary coil array. (723e) can be matched to be a connection between. In addition, the sensing unit may detect and monitor the current and voltage between the resonance circuit and the primary coil array 723e, and the multiplexer 723d may connect/disconnect an appropriate primary coil depending on the location of the power receiver 751. have.

The communication and control unit 721 may receive a request message for wireless power from the power receiver 751 and may control connection to an appropriate primary coil array through the multiplexer 723d. In addition, the communication and control unit 721 controls the inverter 723a to adjust the amount of wireless power by executing a power control algorithm and protocol, and controls the primary coil array 723e to transmit wireless power to the power receiver 751 . can do. Hereinafter, the primary coil array 723e of the power transmitters 720 and 730 will be described with reference to FIG. 11 .

11 is a diagram illustrating an example of configuring a primary coil array for a power transmitter.

In FIG. 11, (a) is an example showing an upper single layer of the primary coil layer, (b) is an example showing one side of the primary coil array, (c) shows an upper single layer of the primary coil array One example.

The primary coil may have a circular shape and a single layer, and the primary coil array may be composed of a plurality of primary coil layers having a hexagonal grid area.

Referring to FIG. 11 , the primary coil array parameters may include d _o , d _i , d _c , da _a , d _h , t ₂ and t ₃ . d _o is the outer diameter of the primary coil layer, d _i is the inner diameter of the primary coil layer, _{d c} is the thickness of the primary coil layer, da is the thickness of the primary coil array, and d _h is between adjacent primary coil layers. A center distance of , t ₂ may be represented by an offset of the second primary coil layer array, and t ₃ may be represented by an offset of the third primary coil layer array.

Referring back to FIG. 7 , the system controller 710 may control wireless power transmission with at least one wireless power receiver 750 . Accordingly, the wireless power transmitter 700 may transmit wireless power to a plurality of wireless power receivers (not shown). Hereinafter, the system controller 710 that performs a control operation of the wireless power transmitter 700 will be described in detail with reference to FIG. 12 .

12 is a flowchart illustrating a control operation of a wireless power transmitter.

Referring to FIG. 12 , the control operation of the wireless power transmitter may include selecting, pinging, identifying and configuring, and transmitting power. can

The selecting step may monitor the interface surface for location and removal of the wireless power receiver. For example, in the selecting step, at least one wireless power receiver present in a free location may be discovered and monitored, and an entity other than the wireless power receiver may be distinguished (eg, foreign objects, keys, coins, etc.). .

In addition, when the information on the wireless power receiver is insufficient, the selecting may select related information by repeatedly performing the pinging, identification, and setting steps. In addition, the selecting may select a primary coil to transmit wireless power to the wireless power receiver. In addition, the selecting may switch to a standby mode when the primary coil is not selected.

The pinging may be performed by performing a digital ping and waiting to receive a response to the wireless power receiver. In addition, the pinging may extend the digital ping and maintain the level of the digital ping when the wireless power receiver is discovered. In addition, in the case of not extending the digital ping, the step of pinging may return to the step of selecting again.

In the identifying and setting, the selected wireless power receiver may be identified, and wireless power amount setting information requested by the wireless power receiver may be acquired. Also, the identifying and setting steps may set the extended digital ping to end, and return to selecting again to discover another wireless power receiver.

The transmitting of power may transmit a requested amount of wireless power to the identified wireless power receiver, and may adjust the current of the primary coil based on the control data. Also, when the transmission of the requested amount of wireless power to the identified wireless power receiver is completed, the step of transmitting power may stop wireless power transmission to the identified wireless power receiver.

13 is a diagram for explaining a configuration of a power transmitter according to an embodiment.

The power transmitter 1300 shown in FIG. 13 includes a power converter 1310 including an inverter, a magnetic induction transmitter 1320 for transmitting power in a magnetic induction method, and a magnetic resonance transmitter for transmitting power in a magnetic resonance method. 1330 may be included.

The magnetic induction transmitter 1320 and the magnetic resonance transmitter 1330 may be turned on/off in a time division manner or may be simultaneously turned on/off. Accordingly, the power transmitter 1300 may simultaneously transmit power to the magnetic induction type wireless power receiver and the magnetic resonance type wireless power receiver.

14 is a diagram illustrating an example of a connection relationship between the output terminal of the inverter included in the power conversion unit 1300 of FIG. 13 and the magnetic induction transmitter 1320 and the magnetic resonance transmitter 1330 of FIG.

13 and 14 , the power transmitter 1300 controls the first switch 1410 , the second switch 1420 , and the third switch 1430 to control a magnetic induction transmission mode, a magnetic resonance transmission mode, and a hybrid mode. can operate as In this case, the hybrid mode may be a mode in which magnetic induction power transmission and magnetic resonance power transmission are simultaneously performed.

In order to determine the operation mode of the power transmitter 1300, the wireless power transmitter may communicate with the wireless power receiver or measure a change in impedance, and if the type of the wireless power receiver is not clear, hybrid It can also operate in mode.

The power supply unit 1311 applies a DC voltage to the switch unit 1315 , and the driving unit 1313 controls the switch unit 1315 to output an AC voltage to the inverter output terminal 1401 .

The magnetic induction transmitter 1320 of FIG. 13 may include a first capacitor 1321 and a first inductor 1323 .

The self-resonant transmitter 1330 of FIG. 13 may include a second capacitor 1331 and a second inductor 1333 .

One end of the first switch 1410 may be connected to the inverter output terminal 1401 , and the other end may be connected to the first capacitor 1321 .

One end of the second switch 1420 may be connected to the inverter output terminal 1401 , and the other end may be connected to the second capacitor 1331 .

In the magnetic induction transmission mode, the first switch 1410 may be turned on, and the second switch 1420 and the third switch 1430 may be turned off.

In the first self-resonance transmission mode, the first switch 1410 may be turned off and the second switch 1420 may be turned on.

In the second self-resonance transmission mode, the first switch 1410 may be turned on and the third switch 1430 may be turned on.

At this time, when the third switch 1430 is turned on, the power transmitter 1300 always turns on the first switch and always turns off the second switch 1420 .

When the third switch 1430 is turned on in the self-resonant transmission mode, the second capacitor 1331 and the second inductor 1333 form a closed loop. In this case, the closed loop may be referred to as a resonator. In the second self-resonant transmission mode, energy may be induced from the first inductor 1323 to the second inductor 1333 and then transferred to the wireless power receiver through the resonator.

In the second self-resonant transmission mode, since the second capacitor 1331 and the second inductor 1333 operate as resonators, they do not affect the natural resonant frequency of the entire system. Accordingly, energy in the second self-resonance transmission mode may be transferred to the wireless power receiver with higher efficiency than in the first self-resonance transmission mode. Accordingly, the second switch 1320 shown in FIG. 14 may be removed.

The power transmitter 1300 may operate in a hybrid mode by turning on/off the first switch 1410 and the second switch 1320 in time division. In addition, the power transmitter 1300 may operate in a hybrid mode by turning the third switch 1430 on/off in time division while the first switch 1410 is always on.

Meanwhile, in FIG. 14 , the first capacitor 1321 and the first inductor 1323 may be equivalent circuits of an induction coil, and may be referred to as a first capacitance and a second inductance, respectively. Similarly, the second capacitor 1331 and the second inductor 1333 may be equivalent circuits of a resonant coil, and may be referred to as a second capacitance and a second inductance, respectively.

FIG. 15 shows a configuration example of the magnetic induction transmitter 1320 and the magnetic resonance transmitter 1330 of FIG. 13 .

Referring to FIG. 15 , the magnetic induction transmitter 1320 is configured as a single coil or coil array 1520 , and the magnetic resonance transmitter 1330 is configured as a resonant coil 1530 surrounding the coil array 1520 . have.

The coil array 1520 may include a plurality of coil cells 1521 , 1523 , 1525 , and 1527 . Of course, the coil array 1520 may include a plurality of primary coils configured as shown in FIG. 9 or 11 .

In the magnetic induction transmission mode, only some of the plurality of coil cells or all of the coil cells may be turned on according to the amount of power required of the wireless power receiver.

Also, when the coil array 1520 includes a plurality of coil cells, only some of the plurality of coil cells or all of the coil cells may be turned on according to the amount of power required of the wireless power receiver in the second self-resonance transmission mode.

FIG. 16 is a view for explaining a method of controlling the primary coil array of FIG. 11 according to an exemplary embodiment.

As described in FIG. 12 , the wireless power transmitter may operate as a step of transmitting power (Power Transfer) after the steps of identification and configuration.

In this case, when a new wireless power receiver appears or a foreign object is present in the power transfer step, a method for controlling the operation of the primary coil array is required.

Referring to FIG. 16 , a primary coil array 1600 according to an embodiment may include a plurality of primary coils and a plurality of sensors 1640 .

In this case, the sensor 1640 may be a pressure sensor or a temperature sensor. In other words, the primary coil array 1600 may include a plurality of pressure sensors and a plurality of temperature sensors.

The sensor 1640 may be provided at a plurality of positions of the primary coil array 1600 . Accordingly, the wireless power transmitter may detect a new object at a specific location and a change in temperature at a specific location due to a change in pressure through the sensor 1640 .

For example, in the "Power Transfer" step of transmitting power to the first wireless power receiving device 1610 in the first time interval, when the new wireless power receiving device 1620 is located at a specific location of the primary coil array 1600 , , the sensing value of the pressure sensor at the corresponding position may change.

In this case, the wireless power transmitter may stop the "Power Transfer" step and operate as a step of re-identification and configuration.

Meanwhile, in the "Power Transfer" step, the foreign material 1630 may be positioned on the primary coils that are being driven or on the primary coils that are not being driven.

In this case, the wireless power transmitter may detect an increase in the temperature of a specific location through the temperature sensor. If the temperature rises above the preset threshold, the driving may be stopped by turning off the primary coils driven around the temperature sensor (eg, four coils around the temperature sensor).

In addition, even when the primary coils around the temperature sensor that sense the temperature rise are turned off, if the temperature does not fall below the threshold or rises, the operation of the entire primary coil array may be temporarily stopped. In addition, in order to detect foreign substances, the "Power Transfer" step may be stopped, and it may operate as a step of re-identification and configuration.

In one embodiment, the temperature sensor may be provided in only three or four places of the entire primary coil array 1600 . When three temperature sensors are provided, it may be determined in which cell the temperature has risen above a threshold value by using the temperature difference value measured by the three sensors.

For example, when the first temperature sensor, the second temperature sensor, and the third temperature sensor are arranged in a triangular shape, and each of the sensing values is A, B, C, values of AB, BC, CA or their absolute values The pre-measured values are stored in a table according to AB, and if AB is the largest value and A is greater than B and a value greater than the threshold value by a certain value, the primary coils around A can be turned off. Alternatively, when A is 25, B is 24.5, and C is 24.6, it is also possible to set to turn off cells that are more than a specific distance from B among cells between A and C.

Meanwhile, transmittable power per each primary coil included in the primary coil array 1600 may be limited due to temperature rise, electromagnetic wave problems, and the like. Therefore, the wireless power transmitter determines at least one primary coil to be driven in order to transmit power to the wireless power receiver, and when the maximum transmission power of the primary coil to be driven is greater than the required power of the wireless power receiver It is also possible to initiate power transmission only to .

For example, the wireless power transmitter may determine the location and required amount of power P _request of the wireless power receiver through communication, and calculate the transmittable amount of power P _sum of all primary coils to be driven at the corresponding location. In this case, the number of primary coils to be driven may be limited to a preset number per one wireless power receiver. The wireless power transmitter may turn on the corresponding primary coils only when P _sum is greater than P _request .

17 is a diagram for explaining a power transfer control algorithm of a wireless power transmitter.

Power transmission control of the wireless power transmitter may be performed using a Proportional Integral Differential (PID) algorithm. The example shown in Fig. 17 shows an example of the PID algorithm.

In a magnetic induction type wireless power transmission system, an example of PID parameters for controlling an operating frequency is shown in [Table 1], and an example of PID parameters for controlling a duty cycle is shown in [Table 2].

[Table 1]

[Table 2]

In the power transfer step, the wireless power transmitter may adjust the current of the primary coil based on the control data. In this case, the current control of the primary coil may be performed based on the PID algorithm.

In Fig. 17, index j = 1, 2, 3, ... denotes a sequence of “Control Error Packets”, and “Control Error Packet” denotes a message that the wireless power transmitter receives from the wireless power receiver in a power transfer step.

를 수학식 1과 같이 계산할 수 있다. When the wireless power transmitter receives the j-th (j ^th ) Control Error Packet, the new primary cell current

can be calculated as in Equation 1.

[Equation 1]

는 j번째 Control Error Packet에 담긴 제어 오류 값(Control Error Value)를 나타내고,

는 전력 전송(Power Transfer) 단계에서 최초로 1차 코일에 공급된 전류를 나타낸다. here,

represents the Control Error Value contained in the j-th Control Error Packet,

denotes the current supplied to the primary coil for the first time in the power transfer step.

The wireless power transmitter may calculate a difference between a new primary cell current and an actual primary cell current as shown in Equation (2).

[Equation 2]

는 루프의 i-1 번째 반복에서 결정된 1차 셀 전류를 나타내고,

는 루프의 시작에서의 실제(actual) 1차 셀 전류를 나타낸다. 인덱스 i=1, 2, 3,…i_max는 PID 알고리즘 루프의 반복 횟수를 나타낸다. here,

denotes the primary cell current determined in the i-1th iteration of the loop,

denotes the actual primary cell current at the beginning of the loop. Index i=1, 2, 3,… i _max represents the number of iterations of the PID algorithm loop.

The wireless power transmitter may calculate a proportional term, an integral term, and a derivative term as shown in Equation (3).

[Equation 3]

Here, Kp is the proportional gain, Ki is the integral gain, Kd is the derivative gain, and t _inner represents the time required to execute the PID algorithm loop.

The wireless power transmitter calculates the sum of the proportional term, the integral term, and the derivative term as shown in Equation (4).

[Equation 4]

를 제한해야만 한다.In the calculation of Equation 4, the wireless power transmitter is the sum

must be limited

The wireless power transmitter must calculate a new value of the controlled variable as in Equation 5.

[Equation 5]

는 제어된 변수에 의존하는 조정계수(scaling factor)이다. here,

is a scaling factor that depends on the controlled variable.

The new value of the controlled variable is passed to the power conversion unit. The new value of the controlled variable can be used as the current regulation limit of the primary coil.

According to an embodiment, the wireless power transmitter may change the value of “PID output limit” according to the number of driven coils among the coils included in the primary coil array.

For example, the wireless power transmitter may increase the value of "PID output limit" as the number of driven cells increases, and the device may decrease the value of "PID output limit" as the number of driven cells decreases.

Accordingly, by controlling the maximum output power of each of the single coils in the cell, it is possible to protect the wireless power transmitter and to transmit stable power.

Also, according to an embodiment, the wireless power transmitter may limit the voltage and duty used for power control according to the number of driven cells.

The wireless power transmitter may limit power input to the primary coil array according to the number of driven coils among the coils included in the primary coil array.

Also, the wireless power transmitter may limit the output power of the inverter according to the number of driven coils among the coils included in the primary coil array.

3 to 7 are descriptions of a method for transmitting power in a magnetic resonance method, and FIGS. 8 to 12 are diagrams illustrating a method for transmitting power in a magnetic induction method. An example of transmitting power in a magnetic resonance manner is described in detail in Prior Art 4. And, FIGS. 13 to 17 show a hybrid scheme.

8 to 12 , the magnetic induction method may be applied to a mouse pad independently of a main device in a local computing environment to transmit power to the mouse on the mouse pad.

18 shows a configuration of a wireless power transmitter according to an embodiment.

Referring to FIG. 18 , the wireless power transmitter 1800 includes a control unit 1810 and a communication unit 1820 . Of course, the wireless power transmitter 1800 may further include a power transmitter 1830 for transmitting power to the wireless power receiver.

The control unit 1810 may include at least one processor, and may include a transmit power value estimator 1811 , a determination unit 1813 , and a charge state determination unit 1815 that may be temporarily implemented by the control unit. .

The transmit power value estimator 1811 estimates the transmit power value based on a control error value (CEV) periodically received from the wireless power receiver in the power transmission step.

The determination unit 1813 determines that the normal stable state (NSS) has entered when the transmission power value is maintained without fluctuation for more than a preset time.

The charging state determining unit 1815 determines the current charging state as a 'foreign substance generation state' or a 'load change state' when the rise width of the transmission power value exceeds a preset threshold value.

The charging state determination unit 1815 is configured to determine the difference between the current transmission power value and the power value at the time of entering the NSS within a predetermined determination time from the time when the rise width of the transmission power value exceeds a predetermined threshold value. When it is less than a preset threshold, the current charging state may be determined as a 'load change state'.

The state of charge determination unit 1815 may determine the current state of charge as a 'foreign matter generation state' when the state in which the rise width of the transmission power value exceeds a preset threshold value exceeds the preset determination time is maintained. have.

The state of charge determination unit 1815 is a transition interval from a first time point at which the transmit power value starts to rise after entering the NSS to a second time point at which a rise width of the transmit power value exceeds a preset threshold value. Interval), the 'foreign matter generation state' or the 'load change state' may be determined based on the current charging state.

When the transition interval is greater than a reference value, the state of charge determination unit 1815 may determine the current state of charge as a 'foreign matter generation state'.

19 illustrates a method for determining a charging state of a wireless power transmitter according to an embodiment. 20 to 24 are exemplary views for explaining various cases for determining the state of charge.

Referring to FIG. 19 , in step 1910, the wireless power transmitter estimates a transmission power value based on a control error value (CEV) periodically received from the wireless power receiver in the power transmission step.

In a wireless power transmission system, a wireless power transmitter (also called Tx) enters a power transfer phase and performs power control to transmit power to a wireless power receiver (also called Rx).

In this case, the Tx may receive a control error value (CEV) from the Rx and perform power control using the received CEV.

Since the Control Error Value is a parameter closely related to the received power, there is no need to calculate the received power separately, and by monitoring the CEV, the received power can be inferred based on the transmit power.

Tx may estimate the transmit power using the PID value. For example, by monitoring the initial power value and the PID value, the current transmission power can be estimated.

In other words, the current transmission power may be expressed as follows.

Depending on the type of Rx, CEV converges to '0' while normal power is transmitted, or the sum of CEVs for a predetermined time converges to '0'.

Therefore, the current transmission power when the Control Error Value is in the normal state is stored as the transmission power in the normal state, and when power higher than this power is transmitted, it can be determined that a foreign material is present.

Also, as the charging level of Rx increases, the required power of Rx may decrease. Therefore, in the case of transmitting power lower than the transmission power in the normal state, it is not determined that a foreign material is present.

In FIG. 20, CEV0, CEV1, CEV2, CEV3, CEV4, and CEV5 respectively represent a time point at which CEV is received in Rx and a CEV value at each time point.

In step 1920, when the transmission power value is maintained without change for a predetermined time or more, it is determined that the wireless power transmitter has entered the Normal Stable State (NSS) shown in FIGS. 20 to 24 .

In step 1930, the wireless power transmitter monitors an increase in the transmit power value based on a control error value received after entering the NSS.

For example, after determining that the Tx has entered the NSS between the time points CEV3 and CEV4 shown in FIG. 21 , the current transmit power value may be estimated by calculating a PID value based on the received CEV4. If a foreign material (FO) enters the charging area between the time points of CEV4 and CEV5, the current transmit power measured at the time point of CEV5 appears to be increased.

In step 1940, when the rise width of the transmission power value exceeds a preset threshold value, the wireless power transmitter determines the current charging state as a 'foreign substance generation state' or a 'load change state'.

For example, in FIG. 21 , if a value obtained by subtracting a power value in a normal state (Normal Stable State Power) from a current transmission power (Present Stable State Power) measured at time point CEV5 in FIG. can be

On the other hand, even when a load change occurs due to a sudden increase in power use on the Rx side, there may be a case in which the increase in the current transmission power exceeds a threshold value.

For example, as shown in FIG. 22 , a load change of Rx may occur between a time point of CEV 4 and a time point of CEV 5 . In this case, Rx may increase the CEV value to request higher power to Tx.

Since most of the load fluctuations in the charging state have a short duration, it is possible to distinguish between FO and load fluctuations by determining whether Present Stable State Power is the same as Normal Stable State Power after a certain period of time.

For example, as shown in FIG. 23 , in the case of load fluctuation, the current transmission power rises above the threshold value at the time of CEV5, and then returns to the NSS state after a predetermined time elapses. In other words, in the example of FIG. 23 , the NSS state may be determined again after the CEV15 time point.

Accordingly, Tx is the current transmission power value within a preset determination time (for example, within 10 CEV intervals) from a time point (CEV5 or CEV6 time in FIG. 23) when the rise width of the transmission power value exceeds a preset threshold value. When the difference between the power value at the time of entering the NSS is equal to or less than the preset threshold value, the current charging state may be determined as a 'load change state'.

On the other hand, when a foreign material absorbs power (eg, a metal, etc.), it may take longer to increase the transmission power due to a load change and the increase in the transmission power due to the foreign material.

For example, (A) of FIG. 24 shows a transmission power curve in which the transmission power increases due to a load change, and (B) shows a transmission power curve in which the transmission power increases due to the generation of foreign substances.

As shown in FIG. 24 , the Transition Interval of the increase of the transmit power due to the load change is shorter than the Transition Interval due to the generation of foreign substances. Therefore, it is also possible to distinguish the load fluctuation state and the foreign matter generation state through the length of the transition interval.

As described above, depending on the type of Rx, CEV may converge to '0' while normal power is transmitted, or the sum of CEVs for a predetermined time may converge to '0'.

Accordingly, by monitoring only the control error value periodically received from the wireless power receiver in the power transmission step, it is also possible to estimate the load fluctuation state and the foreign matter generation state.

The control error value received in the steady state may be '0' or a value very close to '0'. Therefore, when the stabilization reference value is set to a number slightly larger than '0' (eg, 0.1, etc.), the control error value periodically received from the wireless power receiver in the power transmission step is greater than or equal to the preset number of times or less than the preset stabilization reference value. When maintained as , it can be determined that the normal stable state (NSS: Normal Stable State) has entered.

At this time, the rise width of the control error value received after entering the NSS is monitored, and when the rise width of the control error value received after entering the NSS exceeds the stabilization reference value, the current charging state is set to a 'foreign substance generation state' ' or 'load change state'.

At this time, similar to step 1940 of FIG. 19 , if a control error value equal to or less than the stabilization reference value is received within a preset number of determinations after the rise width of the control error value exceeds the stabilization reference value, the current charging state is changed to a 'load change' status can be determined.

In addition, when a control error value exceeding the stabilization reference value is received by exceeding the number of determinations, the current charging state may be determined as a 'foreign matter generation state'.

The device described above may be implemented as a hardware component, a software component, and/or a combination of the hardware component and the software component. For example, devices and components described in the embodiments may include, for example, a processor, a controller, an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field programmable array (FPA), It may be implemented using one or more general purpose or special purpose computers, such as a programmable logic unit (PLU), microprocessor, or any other device capable of executing and responding to instructions. The processing device may execute an operating system (OS) and one or more software applications running on the operating system. The processing device may also access, store, manipulate, process, and generate data in response to execution of the software. For convenience of understanding, although one processing device is sometimes described as being used, one of ordinary skill in the art will recognize that the processing device includes a plurality of processing elements and/or a plurality of types of processing elements. It can be seen that may include For example, the processing device may include a plurality of processors or one processor and one controller. Other processing configurations are also possible, such as parallel processors.

The software may comprise a computer program, code, instructions, or a combination of one or more thereof, which configures a processing device to operate as desired or is independently or collectively processed You can command the device. The software and/or data may be any kind of machine, component, physical device, virtual equipment, computer storage medium or device, to be interpreted by or to provide instructions or data to the processing device. , or may be permanently or temporarily embody in a transmitted signal wave. The software may be distributed over networked computer systems and stored or executed in a distributed manner. Software and data may be stored in one or more computer-readable recording media.

The method according to the embodiment may be implemented in the form of program instructions that can be executed through various computer means and recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, etc. alone or in combination. The program instructions recorded on the medium may be specially designed and configured for the embodiment, or may be known and available to those skilled in the art of computer software. Examples of the computer-readable recording medium include magnetic media such as hard disks, floppy disks and magnetic tapes, optical media such as CD-ROMs and DVDs, and magnetic such as floppy disks. - includes magneto-optical media, and hardware devices specially configured to store and execute program instructions, such as ROM, RAM, flash memory, and the like. Examples of program instructions include not only machine language codes such as those generated by a compiler, but also high-level language codes that can be executed by a computer using an interpreter or the like. The hardware devices described above may be configured to operate as one or more software modules to perform the operations of the embodiments, and vice versa.

As described above, although the embodiments have been described with reference to the limited embodiments and drawings, various modifications and variations are possible by those skilled in the art from the above description. For example, the described techniques are performed in a different order than the described method, and/or the described components of the system, structure, apparatus, circuit, etc. are combined or combined in a different form than the described method, or other components Or substituted or substituted by equivalents may achieve an appropriate result.

Therefore, other implementations, other embodiments, and equivalents to the claims are also within the scope of the following claims.

Claims (13)

Estimating a transmission power value based on a control error value (CEV) contained in a control error packet that is a message periodically received by the wireless power transmission device from the wireless power reception device in the power transmission step ;
determining that the transmission power value has entered a Normal Stable State (NSS) when the transmission power value is maintained without fluctuation for more than a preset time;
monitoring a rise width of the transmit power value based on a control error value received after entering the NSS; and
When the rise width of the transmit power value exceeds a preset threshold, determining the current charging state as a 'foreign matter generation state' or 'load change state'
A method for determining the charging state of a wireless power transmission device. According to claim 1,
The determining step is
When the difference between the current transmission power value and the power value at the time of entering the NSS becomes less than or equal to the preset threshold value within a preset determination time from the time when the rise width of the transmission power value exceeds the preset threshold value, the To determine the current charging state as a 'load change state'
A method for determining the charging state of a wireless power transmission device. 3. The method of claim 2,
The determining step is
If a state in which the rise width of the transmission power value exceeds a preset threshold value is maintained in excess of the preset determination time, the current charging state is determined as a 'foreign substance generation state'
A method for determining the charging state of a wireless power transmission device. According to claim 1,
The determining step is
After entering the NSS, the current charging based on a transition interval from a first time point at which the transmit power value starts to rise to a second time point at which the rise width of the transmit power value exceeds a preset threshold value To determine the state of the 'foreign substance generation state' or 'load change state'
A method for determining the charging state of a wireless power transmission device. 5. The method of claim 4,
In the determining step, when the transition interval is greater than a reference value, determining the current charging state as a 'foreign substance generation state'
A method for determining the charging state of a wireless power transmission device. In the power transmission step, the control error value (CEV) contained in the control error packet, which is a message periodically received by the wireless power transmitter from the wireless power receiver, is more than a preset number of times or less than the preset stabilization reference value. If maintained as, determining that it has entered a normal stable state (NSS: Normal Stable State);
monitoring a rise width of a control error value received after entering the NSS; and
When the rise width of the control error value received after entering the NSS exceeds the stabilization reference value, determining the current charging state as a 'foreign matter generation state' or 'load change state'
A method for determining the charging state of a wireless power transmission device. 7. The method of claim 6,
The determining step is
When a control error value equal to or less than the stabilization reference value is received within a preset number of determinations after the rise width of the control error value exceeds the stabilization reference value, the current charging state is determined as a 'load change state'
A method for determining the charging state of a wireless power transmission device. 7. The method of claim 6,
The determining step is
When a control error value exceeding the stabilization reference value is received by exceeding a preset number of determinations after the rise width of the control error value exceeds the stabilization reference value, the current charging state is determined as a 'foreign matter generation state'
A method for determining the charging state of a wireless power transmission device. A wireless power transmitter comprising a communication unit and a control unit for communicating with a wireless power receiving apparatus, wherein the control unit includes at least one processor, and is temporarily implemented by the control unit:
Transmission for estimating a transmission power value based on a control error value (CEV) contained in a control error packet that is a message periodically received by the wireless power transmission device from the wireless power reception device in the power transmission step power value estimation unit;
a determination unit that determines that the transmission power value has entered a Normal Stable State (NSS) when the transmission power value is maintained without fluctuation for more than a preset time; and
The rise width of the transmit power value is monitored based on the control error value received after entering the NSS, and when the rise width of the transmit power value exceeds a preset threshold, the current charging state is set to a 'foreign substance generation state' or Including a state of charge determination unit to determine the 'load change state'
Wireless power transmission device. 10. The method of claim 9,
The state of charge determination unit
When the difference between the current transmission power value and the power value at the time of entering the NSS becomes less than or equal to the preset threshold value within a preset determination time from the time when the rise width of the transmission power value exceeds the preset threshold value, the To determine the current charging state as a 'load change state'
Wireless power transmission device. 11. The method of claim 10,
The state of charge determination unit,
If a state in which the rise width of the transmission power value exceeds a preset threshold value is maintained in excess of the preset determination time, the current charging state is determined as a 'foreign substance generation state'
Wireless power transmission device. 10. The method of claim 9,
The state of charge determination unit,
After entering the NSS, the current charging based on a transition interval from a first time point at which the transmit power value starts to rise to a second time point at which the rise width of the transmit power value exceeds a preset threshold value To determine the state of the 'foreign substance generation state' or 'load change state'
Wireless power transmission device. 13. The method of claim 12,
The state of charge determination unit,
When the transition interval is greater than a reference value, the current charging state is determined as a 'foreign substance generation state'.
Wireless power transmission device.

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