KR102544408B1 - Wireless power transmission and charging system - Google Patents

Abstract

A wireless power transmission and charging system is disclosed. A method for determining a state of charge of a wireless power transmitter includes estimating a transmission power value based on a control error value (CEV) periodically received from a wireless power receiver in a power transmission step, and the transmission power value is Determining that a normal stable state (NSS) has been entered when the change is maintained for a predetermined time or longer, and determining an increase in the transmit power value based on a control error value received after entering the NSS. Monitoring and determining the current charging state as a 'foreign matter generation state' or a 'load fluctuation state' when the range of increase in the transmission power value exceeds a predetermined threshold value.

Description

Wireless power transmission and charging system {WIRELESS POWER TRANSMISSION AND CHARGING SYSTEM}

The technical field relates to power control of a wireless power transmission system that wirelessly transmits and receives power.

A wireless power transmission system includes a wireless power transmitter that wirelessly transmits electrical energy and a wireless power receiver that receives electrical energy from the wireless power transmitter. The wireless power transfer system can be applied to a local computing environment.

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

Methods of wirelessly transmitting electrical energy can be classified into magnetic induction methods, magnetic resonance methods, and electromagnetic wave methods according to the principle of transmitting electrical energy.

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

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

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

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

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

In this case, '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 Document" 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 Publication No. 2014-0057503 (May 13, 2014), title of the invention "Wireless power receiving device and its power control method" Prior art 2: Korean Patent Publication No. 2014-0061337 (2014.05.13), title of invention "Wireless power transmission device and wireless power transmission method"

A wireless power transmission and charging system is proposed, and an improved configuration of the wireless power transmission and charging system is proposed.

A method for determining a state of charge of a wireless power transmitter according to an embodiment includes the steps of estimating a transmission power value based on a control error value (CEV) periodically received from a wireless power receiver in a power transmission step; , determining that the transmission power value has entered a normal stable state (NSS) if the transmission power value remains unchanged for a predetermined time or longer, and the transmission based on a control error value received after entering the NSS Monitoring an increase in the power value; and determining a current charging state as a 'foreign matter generation state' or a 'load fluctuation state' when the increase in the transmit power value exceeds a preset threshold.

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

A wireless power transmitter 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 a wireless power receiver in a power transmission step; If the transmit power value is maintained without change for more than a preset time, a determination unit that determines that a normal stable state (NSS) has entered, and if the increase in the transmit power value exceeds a preset threshold value, the current and a charging state determining unit that determines the charging state as 'foreign substance generation state' or 'load fluctuation state'.

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

In the wireless power transmission device, a current transmission power value may be estimated and a foreign matter detection state may be determined without additional configuration or measurement.

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 for explaining the operation 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 of the amount of power applied by the wireless power transmitter according to the embodiment of FIG. 5 on a time axis.
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 showing an example of configuring two primary coils.
9 is a diagram showing an example of configuring three primary coils.
FIG. 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 showing an example of configuring a primary coil array for a power transmitter.
12 is a flowchart for explaining a control operation of a wireless power transmitter.
13 is a diagram for explaining a configuration of a power transmission unit according to an exemplary embodiment.
14 is a diagram illustrating an example of a connection relationship between an output terminal of an inverter included in the power conversion unit of FIG. 13 and a magnetic induction transmitter and a magnetic resonance transmitter.
FIG. 15 shows an example of the configuration of the magnetic induction transmitter and magnetic resonance transmitter of FIG. 13 .
FIG. 16 is a diagram 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 transmission device according to an embodiment.
19 illustrates a charging state determination method of a wireless power transmission device according to an embodiment.
20 to 24 are exemplary diagrams 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, 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 the authenticated wireless power receiver that has undergone 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 bi-directional 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 predetermined frames. 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 a 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. Also, 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, and 110-n may be preferably 10 cm or less. .

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

In addition, the wireless power transmitter 100 may transmit a control signal to disable the wireless charging function to each of the wireless power receivers 110-1, 110-2, and 110-n. The wireless power receiver receiving the wireless charging function disable control signal 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 to charge batteries included therein. In addition, the wireless power receivers 110-1, 110-2, and 110-n transmit a signal requesting wireless power transmission, information necessary for wireless power reception, wireless power receiver status information, or wireless power transmitter 100 control information to the wireless power transmitter ( 100) can be sent. The information of the transmission signal will be described in more detail later.

In addition, the wireless power receivers 110-1, 110-2, and 110-n may transmit a message indicating a state of charge to the wireless power transmitter 100, respectively.

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 transmission unit 211 , a control unit 212 and a communication unit 213 . In addition, the wireless power receiver 250 may include a power receiver 251, a control unit 252, and a communication unit 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 transmission unit 211 may supply power in the form of an AC waveform, or may supply power in the form of a DC waveform and convert it into an AC waveform using an inverter to supply power in the form of an AC waveform. The power transmission unit 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 easily understand that the power transmission unit 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 to the wireless power receiver 250 in the form of an electromagnetic wave. The power transmission unit 211 may additionally include a loop coil, and thus may transmit or receive predetermined electromagnetic waves. When the power transmission unit 211 is implemented as a loop coil, the inductance L of the loop coil may be changeable. Meanwhile, those skilled in the art will easily understand that the power transmission unit 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 control unit 212 may control the overall operation of the wireless power transmitter 200 by using an algorithm, program, or application required for control read from a storage unit (not shown). The control unit 212 may be implemented in the form of a CPU, microprocessor, or mini computer. Detailed operations 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 a Zigbee communication method of IEEE802.15.4. In addition, the communication unit 213 may use a Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) algorithm. A configuration related to frequency and channel selection used by the communication unit 213 will be described later in detail. On the other hand, the above-described communication method is merely exemplary, and the scope of the present invention is not limited by a specific communication method performed by the communication unit 213.

Meanwhile, the communication unit 213 may transmit a signal related to 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 the capacity of the wireless power receiver 250, the remaining battery capacity, the number of times of charging, usage, battery capacity, and 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 enabling or disabling the charging function by controlling the wireless power receiver 251 of the specific wireless power receiver 250 .

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

Meanwhile, in FIG. 2, the power transmission unit 211 and the communication unit 213 are composed of different hardware and the wireless power transmitter 200 is communicated in an out-band format, but this is exemplary. In the present invention, the power transmission unit 211 and the communication unit 213 are implemented as a single piece of hardware so that the wireless power transmitter 200 can perform communication in an in-band format.

The wireless power transmitter 200 and the wireless power receiver 250 may transmit and receive various signals, and accordingly, the wireless power receiver 250 joins the wireless power network controlled by the wireless power transmitter 200 and transmits and receives wireless power. A charging process may be performed through, and the above-described process will be described later in more detail.

In addition, although FIG. 2 briefly illustrates the configuration of the wireless power transmitter 200 and the wireless power receiver 250, FIG. 3 illustrates the detailed configuration of the wireless power transmitter 200 and the wireless power receiver 250, , 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 transmission unit 211, a control unit 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, a control unit and communication units 252 and 253, a rectifier 254, a DC/DC converter unit 255, a switch unit 256, and a load unit 257. .

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

The DC current output from the driver 214 may be output to the amplifier 215 . The amplifier 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, the output power may be controlled to be high efficiency or high output. The matching unit 216 may adjust the impedance based on the control of the control unit and the communication units 212 and 213 . The matching unit 216 may include at least one of a coil and a capacitor. The control unit and the communication units 212 and 213 may control a connection state with at least one of a coil and a capacitor, and accordingly, impedance matching may be performed.

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 a resonance circuit having the same resonance frequency. For example, the resonant frequency may be determined to be 6.78 MHz. The control and communication units 212 and 213 may communicate with the control and communication units 252 and 253 of the wireless power receiver 250 .

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 direct current form, and may be implemented in the form of a bridge diode, for example. 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, the minimum and maximum values of the 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. The switch unit 256 may maintain an on/off state under the control of the control unit 252 . The load unit 257 may store converted power input from the DC/DC converter unit 255 when the switch unit 256 is in an on state.

4 is a flowchart for explaining the operation 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 each of the different types of power beacons 404 and 405 for detection in each cycle. For example, as shown in FIG. 4 , the wireless power transmitter 400 may apply a power beacon for detection, and the power values of the power beacons 404 and 405 for detection may have different sizes. 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 power beacons 404 and 405 for detection. This 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 non-periodically applies 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 periodically or aperiodically transmit a PTU search signal, 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 a state of the wireless power receiver 450, and may request subscription to a 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 the PRU static signal and the 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 information on a voltage at a downstream stage of a rectifier of the wireless power receiver 450 . A state of the wireless power receiver 450 may be referred to as a boot state.

The wireless power transmitter 400 enters a power transmission mode (S416), and the wireless power transmitter 400 may transmit a PRU command signal, which is a command signal for causing 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 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 settings 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 status, and temperature information. A state of the wireless power receiver 450 may be referred to as an On state.

The wireless power receiver 450 may perform charging by receiving the PRU command signal. For example, the wireless power transmitter 400 enables charging when it has sufficient power to charge the wireless power receiver 450. A PRU command signal to do so may be transmitted. Meanwhile, the PRU command signal may be transmitted whenever the charging state 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 set 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 an error occurrence. 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 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. Upon receiving the PRU warning signal, the wireless power transmitter 400 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 detail with reference to FIG. 6 . FIG. 6 is a graph of the amount of power applied by the wireless power transmitter according to the embodiment of FIG. 5 on a time axis.

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 period in which the wireless power transmitter applies heterogeneous power having a different amount of power to the power transmitter. For example, the wireless power transmitter may be a section in which the second detection powers 601 and 602 and the third detection powers 611, 612, 613, 614, and 615 in FIG. 6 are applied to the power transmitter. Here, the wireless power transmitter may periodically apply the second detection powers 601 and 602 in a second cycle, and may apply the second detection powers 601 and 602 during a second period.

The wireless power transmitter may periodically apply the third detection powers 611, 612, 613, 614, and 615 in a third cycle, and when the third detection powers 611, 612, 613, 614, and 615 are applied, It may be granted during the third period. Meanwhile, although the respective power values of the third detection powers 611, 612, 613, 614, and 615 are shown as being different, the respective power values of the third detection powers 611, 612, 613, 614, and 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 magnitude, 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 sizes, each amount of power of the third detection power 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. and the third detection power 613 may have an amount of power capable of detecting a category 1 wireless power receiver.

Meanwhile, the second detection powers 601 and 602 may be power capable of driving the wireless power receiver. More specifically, the second detection powers 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 in second and third cycles, respectively. When a wireless power receiver is disposed on the wireless power transmitter, an impedance seen 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 an object (S507). When an object is not detected (S507-N), the wireless power transmitter may maintain a power saving mode in which heterogeneous power is 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 perform communication with the wireless power transmitter in a predetermined method based on the driving power 620 . For example, the wireless power receiver may transmit/receive data required for authentication and, based on this, join a wireless power network managed by the wireless power transmitter. However, when a foreign object other than the wireless power receiver is disposed, data transmission and reception cannot be performed. Accordingly, the wireless power transmitter may determine whether the placed object is a foreign substance (S511). For example, the wireless power transmitter may determine the object as a foreign object when not receiving a response from the object for a preset time.

If it is determined to be foreign matter (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 in FIG. 6 in a first cycle. The wireless power transmitter may detect a change in impedance while applying the first power. For example, when a foreign substance is recovered, an impedance change may be detected, and the wireless power transmitter may determine that the foreign substance is recovered. Alternatively, when the foreign material is not collected, the wireless power transmitter cannot detect the impedance change and the wireless power transmitter may determine that the foreign material is not recovered. When the foreign matter is not collected, the wireless power transmitter may output at least one of a lamp and a warning sound to notify 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 that outputs at least one of a lamp and a warning sound.

When it is determined that the foreign matter is not recovered (S515-N), the wireless power transmitter may maintain the latch failure mode (S513). Meanwhile, when it is determined that the foreign matter has been recovered (S515-Y), the wireless power transmitter may re-enter the power saving mode (S517). For example, the wireless power transmitter may apply second powers 651 and 652 and third powers 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 or 730, and the power transmitter 720 or 730 may include a power converter 721 or 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 transmit the wireless 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 magnetic induction primary coil that transmits power wirelessly.

The power pick-up unit 752 may receive wireless power from the power converters 721 and 731, convert the received wireless power into electrical power, and receive the wireless power in a magnetic induction type secondary coil. (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 the top of the interface surface, and a primary coil may be provided on the bottom 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 located on the upper part of the interface surface, so that a gap between the primary coil and the secondary coil is formed. Inductive coupling can be achieved. Hereinafter, the primary coil will be described in detail.

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

Referring to FIG. 8 , the two primary coils may be winding-type coils, and the winding-type coils may be composed of Litz Wire having 115 strands and a diameter of 0.08 mm. Also, the two primary coils may have a racetrack-like shape and may be composed of a single layer. In addition, the parameters of the two primary coils may include d _o and d _h , where d _o is the 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 litz wires having 105 strands and a diameter of 0.08 mm. In addition, the three primary coils may have a 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 , 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 coil. It may be the distance between the center of the coil and the center of the third primary coil.

Referring back to FIG. 7 , the communication and controllers 723 and 733 may communicate with at least one power receiver 752 . In addition, the communication and control units 723 and 733 may receive a request message for necessary wireless power from the power receiver 752, and accordingly, the communication and control units 723 and 733 request wireless power from the power receiver 752. The power conversion unit 721 may be controlled to transmit the

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

FIG. 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 transmission units 720 and 730 may include a communication and control unit 721 and a power conversion unit 723, and the power conversion unit 723 may include an inverter 723a and an impedance matching unit 723b. , a sensing unit 723c, a multiplexer 723d, and a primary coil array 723e.

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 may include a resonant circuit and a primary coil array. (723e) can be matched to be connected. In addition, the sensing unit can sense and monitor the current and voltage between the resonance circuit and the primary coil array 723e, and the multiplexer 723d can connect/disconnect an appropriate primary coil according to the location of the power receiver 751. there is.

The communication and control unit 721 may receive a request message for wireless power from the power receiver 751 and 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 the 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 showing an example of configuring a primary coil array for a power transmitter.

In FIG. 11, (a) is an example of an upper monolayer of the primary coil layer, (b) is an example of one side of the primary coil array, and (c) is an example of an upper monolayer of the primary coil array. This is an example.

The primary coil may be formed of 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 lattice area.

Referring to FIG. 11 , the primary coil array parameters may include d _o , d _i , d _c , d _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, d _a is the thickness of the primary coil array, and d _h is the distance between adjacent primary coil layers. The center distance of , t ₂ may represent an offset of the second primary coil layer array and t ₃ may represent 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 for explaining a control operation of a wireless power transmitter.

Referring to FIG. 12, the control operation of the wireless power transmitter may include a selection step, a ping step, an identification and configuration step, and a power transfer step. can

The selecting step may monitor the interface surface for location and removal of the wireless power receiver. For example, the selecting step may discover and monitor at least one wireless power receiver existing in a free location, and distinguish objects other than the wireless power receiver (eg, foreign objects, keys, coins, etc.) .

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

The pinging may perform digital ping and wait to receive a response from the wireless power receiver. In addition, the pinging step may extend the digital ping and maintain the level of the digital ping when the wireless power receiver is discovered. In addition, when digital ping is not extended, the pinging step may return to the selecting step again.

The identifying and setting may identify the selected wireless power receiver and obtain wireless power setting information requested by the wireless power receiver. Also, the step of identifying and setting may set the extended digital ping to end, and may return to the step of selecting again to discover another wireless power receiver.

In the step of transmitting power, the requested amount of wireless power may be transmitted to the identified wireless power receiver, and current of the primary coil may be adjusted based on control data. In addition, when the transmission of the requested amount of wireless power to the identified wireless power receiver is completed, the transmitting of the power may stop wireless power transmission to the identified wireless power receiver.

13 is a diagram for explaining a configuration of a power transmission unit according to an exemplary 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).

The magnetic induction transmitter 1320 and the magnetic resonance transmitter 1330 may be turned on/off in a time division manner or 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.

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

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

The wireless power transmitter may perform communication with the wireless power receiver or measure a change in impedance in order to determine the operation mode of the power transmitter 1300, and may be hybrid in normal times or when the type of wireless power receiver is not clear. It can also work as a mod.

The power supply unit 1311 applies DC voltage to the switch unit 1315, and the driving unit 1313 controls the switch unit 1315 to output 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 magnetic resonance 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 self-inductive 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 magnetic resonance transmission mode, the first switch 1410 may be turned off and the second switch 1420 may be turned on.

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

The power transmission unit 1300 may operate in a hybrid mode by turning on/off the first switch 1410 and the second switch 1320 in a time division manner. In addition, the power transmission unit 1300 may operate in a hybrid mode by turning on/off the third switch 1430 in a time division manner 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 the induction coil, and may be referred to as first capacitance and second inductance, respectively. Similarly, the second capacitor 1331 and the second inductor 1333 may be equivalent circuits of the 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 may be composed of a single coil or coil array 1520, and the magnetic resonance transmitter 1330 may be composed of a resonant coil 1530 surrounding the coil array 1520. there is.

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 FIG. 11 .

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

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

FIG. 16 is a diagram 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 transmission device may operate in a step of power transfer after steps of identification and configuration.

At this time, when a new wireless power receiver appears or a foreign object exists 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 sensors 1640 may be provided at multiple positions of the primary coil array 1600 . Accordingly, the wireless power transmission device may detect a new object at a specific location due to a change in pressure and a change in temperature at the specific location through the sensor 1640 .

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

At this time, the wireless power transmission device may stop the "Power Transfer" step and operate again in the steps of identification and configuration.

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

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

In addition, even if the primary coils around the temperature sensor that detects the temperature increase are turned off, if the temperature does not drop below the threshold or rises, the operation of the entire primary coil array may be temporarily stopped. Also, in order to detect the foreign matter, the "Power Transfer" step may be stopped, and the identification and configuration steps may be performed again.

In one embodiment, temperature sensors may be provided only in three or four locations of the entire primary coil array 1600 . When three temperature sensors are provided, it may be determined whether the temperature of a cell at a location has risen above a threshold value using temperature difference values 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 sensed value is A, B, C, the values of A-B, B-C, and C-A or absolute values thereof. According to , pre-measured values are stored in a table, and if A-B is the largest value and A is greater than B and greater than a threshold value by a certain value, the primary coils around A may be turned off. Alternatively, if A is 25, B is 24.5, and C is 24.6, it is also possible to set to turn off cells located at a specific distance or more from B among the cells between A and C.

Meanwhile, transmittable power for each primary coil included in the primary coil array 1600 may be limited due to a temperature rise, an electromagnetic wave problem, and the like. Therefore, in order to transfer power to the wireless power receiver, the wireless power transmitter determines at least one primary coil to be driven, and the maximum transmission power of the primary coil to be driven is greater than the required power of the wireless power receiver. Power transmission may be initiated only on

For example, the wireless power transmitter may determine the location of the wireless power receiver and the required amount of power P _request through communication, and calculate the transmittable power amount 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 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 transfer 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 a PID algorithm.

In the magnetic induction type wireless power transmission system, examples of PID parameters for operating frequency control are shown in [Table 1], and examples of PID parameters for duty cycle control are 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 control data. At this time, current control of the primary coil may be performed based on the PID algorithm.

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

를 수학식 1과 같이 계산할 수 있다. When the wireless power transmitter receives the jth (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,

represents the current initially supplied to the primary coil in the power transfer stage.

The wireless power transmitter may calculate the difference between the new primary cell current and the 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-1 iteration of the loop,

represents the actual primary cell current at the start 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 perform 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 transmission device is the sum

should be limited.

The wireless power transmitter must calculate a new value of the controlled variable as shown 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 transmitted 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 one 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 transmission device 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.

Therefore, by adjusting the maximum output power of each of the single coils in the cell, it is possible to protect the wireless power transmission device and to transmit power stably.

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 coils included in the primary coil array.

In addition, 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 show a method for transmitting power in a magnetic induction method. An example of transmitting power in a self-resonant manner is described in detail in Prior Art 4. 13 to 17 show a hybrid method.

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

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

Referring to FIG. 18 , a 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 includes at least one processor and may include a transmission power value estimation unit 1811, a determination unit 1813, and a charging state determination unit 1815 that may be temporarily implemented by the control unit. .

The transmission power value estimator 1811 estimates a transmission 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 a normal stable state (NSS) has been entered when the transmission power value is maintained without change for a predetermined time or longer.

The charging state determining unit 1815 determines the current charging state as a 'foreign substance generation state' or a 'load fluctuation state' when the range of increase in the transmit power value exceeds a preset threshold value.

The charging state determination unit 1815 determines 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 increase in the transmission power value exceeds a predetermined threshold value. When it is below a preset threshold value, the current charging state may be determined as a 'load fluctuation state'.

The charging state determining unit 1815 may determine the current charging state as a 'foreign substance generation state' when the predetermined determination time exceeds the range of the increase in the transmit power value exceeding the predetermined threshold value. there is.

The charging state determination unit 1815 determines the transition interval (Transition Interval), it is possible to determine the current charging state as the 'foreign substance generation state' or the 'load variation state'.

The charging state determining unit 1815 may determine the current charging state as a 'foreign substance generation state' when the transition interval is greater than a reference value.

19 illustrates a charging state determination method of a wireless power transmission device according to an embodiment. 20 to 24 are exemplary diagrams 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 transfer system, a wireless power transmitter (also referred to as Tx) enters a power transfer mode (Power Transfer Phase) and then performs power control to transmit power to a wireless power receiver (also referred to as 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, it is possible to infer the received power based on the transmitted power by monitoring the CEV without the need to calculate the received power separately.

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

In other words, the current transmit power can be expressed as

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

Therefore, it is possible to determine that a foreign object exists when the current transmission power when the control error value becomes a normal state is stored as the transmission power in the normal state, and a higher power than this power is transmitted.

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

In FIG. 20 , CEV0 , CEV1 , CEV2 , CEV3 , CEV4 , and CEV5 indicate time points at which CEV is received in Rx and CEV values at each point in time.

In step 1920, the wireless power transmitter determines that it has entered a normal stable state (NSS) shown in FIGS. 20 to 24 when the transmission power value is maintained without change for more than a preset time.

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 NSS between the time points CEV3 and CEV4 shown in FIG. 21 , the current transmission power value may be estimated by calculating a PID value based on the received CEV4. If the foreign matter (FO) enters the charging area between the time CEV4 and CEV5, the current transmit power measured at the time CEV5 appears as an increased state.

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

For example, in FIG. 21 , if a value obtained by subtracting a power value in a normal state from the present stable state power measured at time point CEV5 is greater than a preset threshold value, it is determined that a foreign matter has occurred. It can be.

Meanwhile, even when load fluctuation occurs due to a sudden increase in power use of the Rx side, a case in which an increase in the current transmission power exceeds a threshold value may occur.

For example, as shown in FIG. 22 , Rx load variation may occur between CEV 4 and CEV 5 . At this time, Rx may request higher power from Tx by increasing the CEV value.

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

For example, as shown in FIG. 23, in the case of a load change, after the current transmission power rises above the threshold value at the time of CEV5, it can return to the NSS state after a certain period of time. In other words, in the example of FIG. 23 , it may be determined to be in the NSS state again after CEV15.

Therefore, Tx is the current transmit power value within a preset decision time (for example, within 10 CEV intervals) from the time when the increase in the transmit power value exceeds the preset threshold (CEV5 or CEV6 in FIG. 23). When the difference between the power value at the time of entering the NSS is equal to or less than the predetermined threshold value, the current charging state may be determined as a 'load variation state'.

Meanwhile, when a foreign material absorbs power (eg, metal), the increase in transmission power due to load variation and the increase in transmission power due to the foreign material may take longer.

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

As shown in FIG. 24, the transition interval of the transmission power increase due to the load change is shorter than the transition interval due to the generation of foreign matter. Therefore, the load variation state and the foreign matter generation state can be distinguished 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 may converge to '0' for a certain period of time.

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

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

At this time, the range of increase in the control error value received after entering the NSS is monitored, and if the range of increase in the control error value received after entering the NSS exceeds the stabilization reference value, the current charging state is set to 'foreign matter occurrence state'. ' or 'load change state'.

At this time, similarly to step 1940 of FIG. 19, if a control error value that is less than or equal to the stabilization reference value is received within a predetermined number of determinations after the increase in the control error value exceeds the stabilization reference value, the current charging state is set as 'load fluctuation'. state can be judged.

In addition, when a control error value exceeding the stabilization reference value is received in excess of the number of determinations, it may be determined that the current charging state is a 'foreign substance generation state'.

The devices described above may be implemented as hardware components, software components, and/or a combination of hardware components and software components. 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. A processing device may run an operating system (OS) and one or more software applications running on the operating system. A processing device may also access, store, manipulate, process, and generate data in response to execution of software. For convenience of understanding, there are cases in which one processing device is used, but those skilled in the art will understand that the processing device includes a plurality of processing elements and/or a plurality of types of processing elements. It can be seen that it can include. For example, a processing device may include a plurality of processors or a processor and a controller. Other processing configurations are also possible, such as parallel processors.

Software may include a computer program, code, instructions, or a combination of one or more of the foregoing, which configures a processing device to operate as desired or processes independently or collectively. The device can be commanded. Software and/or data may be any tangible machine, component, physical device, virtual equipment, computer storage medium or device, intended to be interpreted by or provide instructions or data to a processing device. , or may be permanently or temporarily embodied in a transmitted signal wave. Software may be distributed on networked computer systems and stored or executed in a distributed manner. Software and data may be stored on one or more computer readable 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 on a computer readable medium. The computer readable medium may include program instructions, data files, data structures, etc. alone or in combination. Program commands recorded on the medium may be specially designed and configured for the embodiment or may be known and usable to those skilled in computer software. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks and magnetic tapes, optical media such as CD-ROMs and DVDs, and magnetic media such as floptical disks. - includes hardware devices specially configured to store and execute program instructions, such as magneto-optical media, and ROM, RAM, flash memory, and the like. Examples of program instructions include high-level language codes that can be executed by a computer using an interpreter, as well as machine language codes such as those produced by a compiler. 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 limited examples and drawings, those skilled in the art can make various modifications and variations from the above description. For example, the described techniques may be performed in an order different from the method described, and/or components of the described system, structure, device, circuit, etc. may be combined or combined in a different form than the method described, or other components may be used. Or even if it is replaced or substituted by equivalents, appropriate results can be achieved.

Therefore, other implementations, other embodiments, and equivalents of the claims are 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, which is a message periodically received by the wireless power transmitter from the wireless power receiver in the power transmission step. ;
determining whether a normal stable state (NSS) has been entered based on the transmission power value;
monitoring an increase in the transmit power value; and
Determining the current charging state as a 'foreign substance generation state' or a 'load fluctuation state' when the increase in the transmission power value exceeds a preset threshold value
Method for determining the state of charge of a wireless power transmission device comprising a. According to claim 1,
The determining step is
When the difference between the current transmit power value and the power value at the time of entering the NSS is equal to or less than the preset threshold value within a preset decision time from the time when the increase in the transmit power value exceeds the preset threshold value, A method for determining the charging state of a wireless power transmission device, which determines the current charging state as a 'load change state'. According to claim 2,
The determining step is
Charging of the wireless power transmission device, in which the current charging state is determined to be a 'foreign matter generation state' when the state in which the increase in the transmission power value exceeds the predetermined threshold exceeds the predetermined determination time. How to judge status. According to claim 1,
The determining step is
After entering the NSS, the current charge is based on a transition interval from a first time point at which the transmission power value starts to increase to a second time point at which the increase in the transmission power value exceeds a preset threshold value. The charging state determination method of the wireless power transmission device, which determines the state as the 'foreign matter generation state' or the 'load fluctuation state'. According to claim 4,
The determining step is to determine the current charging state as a 'foreign substance generation state' when the transition interval is greater than the reference value. In the power transmission step, based on the control error value (CEV) contained in the control error packet, which is a message that the wireless power transmitter periodically receives from the wireless power receiver, the normal stable state (NSS: Determining whether or not a normal stable state has been entered;
monitoring an increase in a control error value received after entering the NSS; and
Determining the current charging state as a 'foreign matter generation state' or a 'load fluctuation state' when the range of increase in the control error value received after entering the NSS exceeds the stabilization reference value
Method for determining the state of charge of a wireless power transmission device comprising a. According to claim 6,
The determining step is
When a control error value less than or equal to the stabilization reference value is received within a predetermined number of determinations after the increase in the control error value exceeds the stabilization reference value, the current charging state is determined to be a 'load fluctuation state', wireless power transmission A method for determining the state of charge of a device. According to claim 6,
The determining step is
When a control error value exceeding the stabilization reference value is received by exceeding a predetermined number of determinations after the increase in the control error value exceeds the stabilization reference value, the current charging state is determined as a 'foreign substance generation state' , A method for determining the state of charge of a wireless power transmission device. In the wireless power transmission device including a communication unit and a control unit for performing communication with the wireless power receiver,
The control unit,
at least one processor;
A transmission for estimating a transmission power value based on a control error value (CEV) contained in a control error packet, which is a message that the wireless power transmitter periodically receives from the wireless power receiver in the power transmission step. a power value estimator;
a determination unit that determines whether a normal stable state (NSS) has been entered; and
A charging state determining unit that monitors an increase in the transmission power value and, when the increase in the transmission power value exceeds a predetermined threshold value, determines the current charging state as a 'foreign substance generation state' or a 'load fluctuation state'
including,
The transmission power value estimation unit, the determination unit, and the charge state determination unit are temporarily implemented by the control unit, wireless power transmission device. According to claim 9,
The charging state determination unit,
When the difference between the current transmit power value and the power value at the time of entering the NSS is equal to or less than the preset threshold value within a preset decision time from the time when the increase in the transmit power value exceeds the preset threshold value, A wireless power transmission device that determines the current charging state as a 'load variation state'. According to claim 10,
The charging state determination unit,
If a state in which the increase in the transmission power value exceeds a preset threshold exceeds the preset determination time is maintained, the current charging state is determined as a 'foreign substance generation state'. According to claim 9,
The charging state determination unit,
After entering the NSS, the current charge is based on a transition interval from a first time point at which the transmission power value starts to increase to a second time point at which the increase in the transmission power value exceeds a preset threshold value. A wireless power transmission device that determines the state as the 'foreign substance generation state' or the 'load change state'. According to claim 12,
The charging state determination unit,
If the transition interval is greater than the reference value, the current charging state is determined as a 'foreign substance generation state'.

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