KR20200033815A - Method and apparatus for power control in wireless power transmitting system - Google Patents

Abstract

The present invention relates to a method and an apparatus for controlling power in a wireless power transmission system. The method of the present invention comprises the following steps of: transmitting wireless power to a wireless power reception apparatus located in a charging area through at least one primary coil; receiving a signal including a CEP carrying power control related information from the wireless power reception apparatus through the primary coil; driving a CEP timer for checking whether the CEP is received within a predetermined time; counting an interrupt generated in decoding the signal received through the primary coil; and controlling wireless power transmission and interruption to the wireless power reception apparatus through the primary coil based on the CEP timer and an interrupt count, wherein the CEP timer is initialized when the CEP is received. According to the present invention, a wireless power transmission apparatus additionally determines whether the wireless power reception apparatus is located in the charging area and continuously performs charging even if a CEP packet is not transmitted from the wireless power reception apparatus for a predetermined period or more.

Description

Power control method and apparatus in wireless power transmission system {METHOD AND APPARATUS FOR POWER CONTROL IN WIRELESS POWER TRANSMITTING SYSTEM}

The present invention relates to wireless power transmission, and more particularly, to a power control method and apparatus in a wireless power transmission system.

In general, in order for a portable terminal such as a mobile phone, a laptop, or a PDA to be charged, the portable terminal must receive electric energy (or power) from an external charger. Such a portable terminal includes a battery cell for storing supplied electric energy and circuits for charging and discharging the battery cell (supplying electric energy to the portable terminal).

The electric connection method between the charger and the battery cell for charging the electric energy to the battery cell, receives commercial power and converts it into voltage and current corresponding to the battery cell to supply electric energy to the battery cell through the terminal of the battery cell. Includes terminal supply method.

This terminal supply method is accompanied by the use of a physical cable or a cable. Therefore, when handling a lot of terminal-supply-type equipment, many cables occupy a considerable work space and are difficult to organize and are not good in appearance. In addition, the terminal supply method may cause problems such as instantaneous discharge phenomena due to different potential differences between terminals, burnout and fire caused by foreign matter, natural discharge, and deterioration of battery pack life and performance.

Recently, in order to solve the above problems, charging systems (hereinafter referred to as wireless power transmission systems) and control methods using wireless power transmission methods have been proposed. The wireless power transmission method is also referred to as a contactless power transmission method or a non-contact power transmission method. The wireless power transmission system includes a wireless power transmission device that supplies electrical energy in a wireless power transmission method, and a wireless power reception device that receives electric energy supplied wirelessly from the wireless power transmission device and charges a battery cell.

In the terminal supply method, power transmission can be performed through a terminal connection between a charger and a terminal, and power transmission can be stopped when the terminal is short-circuited. On the other hand, the wireless power transmission system is coupled between the primary coil provided in the charger for charging and the secondary coil provided in the terminal (self-induction and / or due to the characteristic of contactless charging). Or magnetic resonance) is required, and the charger transmits power to the terminal through the magnetic field coupling. In performing wireless power transfer from the charger in such a wireless power transfer system, the charger must be able to determine whether the terminal has been removed from the charging area and stop the power transfer. For example, the terminal transmits a packet, such as a control error packet, indicating to the charger that the corresponding terminal is located in the charging area (or interface surface) to the charger, and the charger is used for a certain period of time (eg For example, if the control error packet is not received for 1.8 seconds), it may be determined that the corresponding terminal is removed from the charging area. However, when the terminal performs battery charging through wireless power reception, in some cases, a serious load fluctuation may occur inside the terminal (hereinafter referred to as a light load condition), thereby distorting packets transmitted from the terminal to the charger. Can occur. In this case, even if the terminal is located in the charging area, the charger determines that the terminal has been removed from the charging area and stops power transmission.

The technical problem of the present invention is to provide a power control method and apparatus in a wireless power transmission system.

Another technical problem of the present invention is to provide a power control method and apparatus in consideration of a light load state of a wireless power receiving device in a wireless power transmission system.

Another technical problem of the present invention is to propose an analysis criterion for a case where a wireless power transmission apparatus receives a distorted signal in a wireless power transmission system.

Another technical problem of the present invention is to propose a criterion for detecting whether a wireless power receiving device is removed from a charging area in a wireless power transmission system.

According to an aspect of the present invention, there is provided a wireless power transmission device that performs power control. The wireless power transmission device is coupled to at least one secondary coil (secondary coil) provided in the wireless power receiving device located in the charging area (coupling) at least one primary coil (primary coil) for transmitting wireless power , A communication unit that receives and decodes a signal including a control error packet (CEP) carrying power control-related information from the wireless power receiver through the primary coil, and checks whether the CEP is received within a predetermined time And a control unit that counts interrupts that occur in decoding a signal received through the primary coil, and the control unit is based on the CEP timer and the interrupt count. Control the wireless power transmission and interruption to the wireless power receiver through the coil, the communication unit is the When the CEP is received, the CEP timer is initialized.

According to another aspect of the present invention, a wireless power transmission method by a wireless power transmission device that performs power control is provided. The method for transmitting wireless power includes transmitting wireless power to a wireless power receiving device located in a charging area through at least one primary coil, and transmitting a signal including a CEP carrying information related to power control through the primary coil. Receiving from a wireless power receiving apparatus, driving a CEP timer to check whether the CEP is received within a predetermined time, counting interrupts generated in decoding a signal received through the primary coil, and And controlling wireless power transmission and interruption to the wireless power receiver through the primary coil based on a CEP timer and the interrupt count, wherein the CEP timer is initialized upon receiving the CEP.

According to the present invention, the wireless power transmitter may further determine whether the wireless power receiver is located in the charging area and continuously perform charging, even though the CEP packet has not been transmitted from the wireless power receiver for a certain period of time.

1 shows the components of a wireless power transmission system according to an example of the present invention.
2 shows an example of a wireless power transmission procedure.
3 shows an example of a procedure for controlling the amount of transmitted power that is performed between the wireless power transmitter and the wireless power receiver.
4 is a flowchart illustrating an example of a method for performing power control by a wireless power transmission device in a wireless power transmission system according to the present invention.
5 is a flowchart illustrating another example of a method of performing power control by a wireless power transmission device in a wireless power transmission system according to the present invention.
6 is an example of a block diagram showing a wireless power transmitter and a wireless power receiver according to the present invention.

The term "wireless power" as used hereinafter is used to mean any form of energy associated with an electric field, magnetic field, electromagnetic field, etc. transmitted from a transmitter to a receiver without the use of physical electromagnetic conductors. Wireless power may also be called a power signal, and may mean an oscillating magnetic flux enclosed by the primary coil and the secondary coil. Power conversion in the system is described herein to wirelessly charge devices including, for example, mobile phones, codeless phones, iPods, MP3 players, headsets, and the like. In general, the basic principle of wireless energy transfer includes, for example, both a magnetic induction coupling method and a magnetic resonance coupling (ie, resonance induction) method. However, various frequencies may be used, including those at which license-exempt operation is permitted at relatively high emission levels, for example below 135 kHz (LF) or at 13.56 MHz (HF).

1 shows the components of a wireless power transmission system according to an example of the present invention.

Referring to FIG. 1, the wireless power transmission system 100 includes a wireless power transmission device 110 and one wireless power reception device 150-1 or n wireless power reception devices 150-1, ..., 150. -n).

The wireless power transmission device 110 includes a primary core block. The primary core block may include a core and one or more primary coils 111. The wireless power transmitter 110 may have any suitable shape, but one preferred shape is a flat platform with a power transmission surface, each in a charging area (eg charging pad) on or near the platform. Wireless power receiving devices 150-1, ..., 150-n may be located.

The wireless power receiving devices 150-1, ..., 150-n are detachable from the wireless power transmitting device 110, and each wireless power receiving device 150-1, ..., 150-n When in the vicinity of the wireless power transmitter 110, a secondary core block is provided that is coupled to an electromagnetic field generated by the primary core block of the wireless power transmitter 110. The secondary core block may include a core and one or more secondary coils (151).

The wireless power transmitter 110 transmits power to the wireless power receivers 150-1, ..., 150-n without direct electrical contact. At this time, it is said that the primary core block and the secondary core block are mutually inductively coupled or resonantly inductively coupled. The primary coil or secondary coil may have any suitable shapes, but may be copper wire wound around a high perameability formation such as, for example, ferrite or amorphous metal.

The wireless power receivers 150-1, ..., 150-n are usually connected to an external load (not shown. Here, also referred to as the actual load of the wireless power receiver), the wireless power transmitter 110 is wireless. Power supplied to the external load. For example, the wireless power receivers 150-1, ..., 150-n can each carry the received power to an object that consumes or stores power, such as a portable electric or electronic device or a rechargeable battery cell or battery. have.

2 shows an example of a wireless power transmission procedure.

Referring to FIG. 2, the wireless power transmitter detects that the wireless power receiver is located in the charging area in the standby mode (S200). Here, the wireless power transmitting device may have various methods for detecting the wireless power receiving device, and the present invention is not limited to a specific method. For example, the wireless power transmitter periodically emits an analog ping of a specific frequency, and the wireless power receiver is located in the charging area based on detection current, resonance shift, or capacitance change. Can detect. As another example, the wireless power transmitter periodically transmits a search signal, and when the wireless power receiver transmits a response signal based on the search signal, the wireless power receiver is located in the charging area based on the response signal. Can be detected. As another example, when the wireless power transmission device periodically transmits a beacon, the wireless power transmission device transmits wireless power by transmitting a search signal or advertisement to the wireless power transmission device in response. The device can detect the wireless power receiving device.

The wireless power transmission device transmits an information request signal to the wireless power reception device in preparation for wireless power transmission (S210). Here, the information request signal may be a signal for requesting ID and required power information of the wireless power receiver. For example, the information request signal may be transmitted in the form of a data packet message. As another example, the information request signal may be transmitted in a digital ping form according to a predefined criterion between the wireless power transmitter and the wireless power receiver.

The wireless power receiver transmits ID and configuration information to the wireless power transmitter in response to the information request signal (S220). Here, the configuration information may include a maximum amount of power that the wireless power receiver desires to receive.

The wireless power transmitter configures parameters for power transmission based on the ID and the configuration information, and performs wireless power transmission to the wireless power receiver (S230). That is, the wireless power transmission device creates a power transmission contract based on the ID and the configuration information, and performs wireless power transmission to the wireless power reception device. The step from the wireless power transmission device to start and stop wireless power transmission to the wireless power reception device may be called a (wireless) power transfer phase.

The wireless power receiver can supply the received wireless power to an external load such as a battery.

The wireless power transmission device monitors the parameters for the power transmission, and may abort the wireless power transmission when any one of the parameters exceeds a defined limit.

In addition, the wireless power transmission step of the S230 may be terminated at the request of the wireless power receiving device. For example, in the case of a battery fully charged, the wireless power receiver may transmit a signal requesting termination of wireless power transmission to the wireless power transmitter.

Meanwhile, after S230, the wireless power receiver continuously transmits a control error packet (CEP) to the wireless power transmitter periodically or aperiodically (S240-1, S240-2, S240-3). This is to perform an amount of power control, that is, power control, transmitted from the wireless power transmitter to the wireless power receiver. Power control procedures such as steps S240-1 to S240-3 may include power control procedures according to the embodiments of FIGS. 3 to 5.

3 shows an example of a procedure for controlling the amount of transmitted power that is performed between the wireless power transmitter and the wireless power receiver.

Referring to Figure 3, the wireless power receiver selects a desired control point (desired control point) (S300). Here, the control point may include current and / or voltage, temperature of any part of the wireless power receiving device, and the like.

The wireless power receiver determines an actual control point based on the wireless power received from the wireless power transmitter (S310).

The wireless power receiving apparatus calculates a control error value using the desired control point and the actual control point (S320). For example, the control error value may be calculated through a (relative) difference between a desired voltage (or current) and an actual voltage (or current).

The wireless power receiver generates a control error packet based on the control error value and transmits it to the wireless power transmitter (S330).

The wireless power transmission apparatus sets a new operation point as necessary based on the control error packet (S340). Here, the operation point may be, for example, at least one of an amplitude, frequency, and duty cycle of an AC voltage applied to the primary coil.

The wireless power transmitter transmits wireless power to the wireless power receiver based on the new operation point (S350). In this case, the wireless power transmitter may maintain the operating point until a new control error packet is received from the wireless power receiver.

Referring to FIG. 2 again, the wireless power transmitter in the charging area when the control error packet is not received again, such as S240-4 within a certain period T (eg, 1.8s) after the control error packet is received. The wireless power receiving device is considered to be removed, and the wireless power transmission is stopped (S250). It is necessary to stop the wireless power transmission even when the user removes the wireless power receiving device receiving the wireless power from the charging area at any time in addition to the above-specified limits of the above parameters and the battery buffer state. Because there is.

However, when the wireless power receiving device performs battery charging through wireless power reception, in the case of a wireless power receiving device and / or a light load condition inside the battery, distortion in packets transmitted from the wireless power receiving device to the wireless power transmitting device This can happen. For example, during charging of a battery connected to (or equipped with) a wireless power receiver, in some cases, charging currents may change irregularly due to instability of the load. In this case, the battery is transmitted from the wireless power receiver. Packets can be distorted. In this case, even if the wireless power receiving device is located in the charging area, the wireless power transmitting device determines that the wireless power receiving device has been removed from the charging area and stops wireless power transmission. This causes unnecessary wireless power transmission interruption and delays battery charging.

4 is a flowchart illustrating an example of a method for performing power control by a wireless power transmission device in a wireless power transmission system according to the present invention. FIG. 4 corresponds to a subsequent procedure including step S230 of FIG. 2.

Referring to FIG. 4, the wireless power transmission device drives a control error packet (CEP) timer (S400). This is to check whether the wireless power transmission apparatus receives the CEP within a predetermined time during the power transmission phase. The timer may be set to a predetermined period T described in FIG. 2. In this case, for example, the timer may be set to 1.8s.

The wireless power transmitter initializes the interrupt count (S405). The wireless power transmitter operates a decoding algorithm to decode a message transmitted from the wireless power receiver, and an interrupt is generated for decoding when a received waveform is received from the wireless power receiver. Specifically, when a waveform is applied to an interrupt port of a machine control unit (MCU) provided in a wireless power transmission device, regardless of a normal waveform and an abnormal waveform (for example, impulsive noise), the rising edge and falling edge of the waveform An interrupt occurs at (falling edge), and the interrupt count is incremented each time an interrupt occurs.

When the interrupt count is initialized, the wireless power transmitter checks whether an interrupt occurs (S410). For example, when the wireless power transmitter receives a CEP packet, an interrupt per CEP packet may be counted about 66 times. One CEP packet includes a header, a message, and a checksum field composed of 1 byte each, and a start bit and a parity bit are included in each field. Since a stop bit may be added, one CEP packet may include a total of 33 bits. In addition, since interrupts are generated at each rising edge and falling edge of a waveform, 66 interrupts may be generated for the 33 bits.

If an interrupt occurs in S410, the wireless power transmitter increases the interrupt count (S415) and checks whether the CEP timer has expired (or timed out) (S420). Here, the CEP timer has a T value as described above.

If an interrupt does not occur in S410, the wireless power transmitter checks whether the CEP timer has expired without increasing the interrupt count (S420).

If the CEP timer has not expired in S420, the wireless power transmitter checks whether there is a message packet received from the wireless power receiver (S425).

If there is no message packet received in S425, the wireless power transmitter returns to S410.

If there is a message packet received in S425 and the packet is a control error packet (CEP) (S430), the wireless power transmitter performs power control as necessary and initializes the CEP timer (S435), then again S405. Return to the procedure.

If there is a message packet received in S425 and the packet is an end power transfer packet (S440), the wireless power transmitter may end the wireless power transmission (S445). Here, the termination power transmission packet indicates a reason for requesting termination of the wireless power transmission, such as, for example, charge complete, over temperature, over voltage, or over current. Information may be included.

Meanwhile, if the CEP timer expires in S420, the wireless power transmitter checks whether the interrupt count exceeds a reference value (S450). This is to determine whether the wireless power receiver is removed from the charging area based on the interrupt count value when the CEP timer expires. Here, the reference value may be set to 500, for example. In this case, if the interrupt count value is greater than the reference value 500, the wireless power transmitter may determine that the wireless power receiver is still located in the charging area even though the CEP timer has expired.

If the interrupt count exceeds the reference value in S450, the wireless power transmitter determines that the wireless power receiver is located in the charging area, initializes the CEP timer (S455), and continues transmitting the wireless power. Then, (S460), the procedure returns to S405.

If the interrupt count does not exceed the reference value in S450, the wireless power transmitter considers that the wireless power receiver is removed from the charging area and stops wireless power transmission (S465).

According to the above-described method, the wireless power transmission device additionally determines whether the wireless power reception device is located in the charging area through the interrupt count even if a CEP packet has not been transmitted from the wireless power reception device for a predetermined period of time, and continuously performs charging. You can. In this case, serious load fluctuations in the wireless power receiving device and / or the battery temporarily occur, such as a light load state of the wireless power receiving device, resulting in distortion in packets transmitted from the wireless power receiving device to the wireless power transmitting device. Even in this case, unnecessary wireless power transmission can be stopped and the battery can be quickly charged.

Meanwhile, when the predetermined period T for the CEP timer is divided into n, and divided into n divided sections, the power control operation according to the present invention may be represented as follows.

5 is a flowchart illustrating another example of a method of performing power control by a wireless power transmission device in a wireless power transmission system according to the present invention.

Referring to Figure 5, the wireless power transmission device drives the CEP timer (S500). The timer may be set to a value (eg, T / n) equal to n equal to the predetermined period T in FIG. 2. For example, when n = 5 and T is 1.8s, the CEP timer may be set to 360 ms.

The wireless power transmitter initializes the interrupt count (S505).

The wireless power transmitter checks whether an interrupt occurs (S510).

If an interrupt occurs in S510, the wireless power transmitter increases the interrupt count (S515) and checks whether the CEP timer has expired (or timed out) (S520). Here, the CEP timer has a T / n value as described above.

If an interrupt does not occur in S510, the wireless power transmitter checks whether the CEP timer has expired without increasing the interrupt count (S520).

Meanwhile, if the CEP timer expires in S520, the wireless power transmitter checks whether the interrupt count exceeds a reference value (S550). Here, the reference value may be set to 100, for example.

If the interrupt count exceeds the reference value in S550, the wireless power transmitter determines that the wireless power receiver is located in the charging area, initializes the CEP timer (S555), and continues the wireless power transmission. (S560) and returns to the S505 procedure.

If the interrupt count does not exceed the reference value in S550, the wireless power transmitter increases the CEP decoding failure count (S562). Here, the CEP decoding failure count indicates the number of consecutive periods in which the CEP decoding has failed and the interrupt is less than or equal to a reference value among the n periods described above. That is, if CEP decoding fails for all of the n sections and an interrupt is detected below a reference value, the wireless power transmitter may be considered to have not received the CEP for the predetermined period T, and in this case, the wireless power receiver It can be seen that has been removed from the filling region.

The wireless power transmitter checks whether the CEP decoding failure count is greater than or equal to n (S563).

If the CEP decoding failure count is less than n in S563, the wireless power transmitter initializes the CEP timer (S555) and returns to the S505 procedure.

If the CEP decoding failure count is greater than or equal to n in S563, the wireless power transmitter considers that the wireless power receiver is removed from the charging area, and stops wireless power transmission (S565).

The remaining steps S525, S530, S535, S540, and S545 are the same as the procedure in FIG. 4, and detailed description is omitted.

6 is an example of a block diagram showing a wireless power transmitter and a wireless power receiver according to the present invention.

Referring to FIG. 6, the wireless power transmitter 600 is connected to at least one primary coil 605 and primary coil 605 to apply electric driving signals to the primary coil 605 to generate an electromagnetic field. It includes a power conversion unit (610), a communication unit 620, and a control unit 630 for.

The wireless power transmitter 600 may have any suitable shape, but one preferred shape is a flat platform with a power transmission surface, and each wireless power receiver 650 in a charging area on or near this platform. Can be laid.

The power conversion unit 610 may be a half-bridge inverter or a full-bridge inverter. The power conversion unit 610 may control the frequency, duty cycle, amplitude, etc. of the electric drive signal applied to the primary coil 605 through switching.

The communication unit 620 controls communication between the wireless power transmitter 600 and the wireless power receiver 650. For example, the communication unit 620 may perform communication with the wireless power receiver 650 through the primary coil 605. As another example, the communication unit 620 may communicate with the wireless power receiver 650 through separate radio frequency (RF) communication means provided in the communication unit 620 and the communication unit 680, respectively.

The communication unit 620 may receive ID, configuration information, CEP, or end power transfer packets from the wireless power receiver 650.

The control unit 630 generates a control signal for power control based on the ID, the configuration information, the CEP, and the termination power transmission packet, and transmits the control signal to the power conversion unit 610.

The control unit 630 may perform necessary control operations to implement the present invention as described above.

The control unit 630 may initialize and drive the CEP timer. Here, the CEP timer may be set to a reference time T or T / n value.

The control unit 630 may initialize and measure an interrupt count related to an interrupt that occurs when the communication unit 630 decodes the received waveform.

The control unit 630 performs power control according to the present invention based on the CEP timer and the interrupt count.

For example, when the CEP timer (eg, T) expires, the control unit 630 compares the interrupt count at the time when the CEP timer expires and a reference value, and when the interrupt count is greater than the reference value, the Despite the expiration of the CEP timer, the wireless power receiver 650 is still considered to be located in the charging area of the wireless power transmitter 600, and wireless power transmission through the primary coil 605 may be continued.

As another example, when the interrupt count is not greater than the reference value, the control unit 630 reports that the wireless power receiver 650 is removed from the charging area according to the expiration of the CEP timer, and the primary coil 605 ) To stop transmitting wireless power.

As another example, when the CEP timer (eg, T / n) expires, the control unit 630 compares the interrupt count at the time when the CEP timer expires and a reference value, and the interrupt count is greater than the reference value. In case, the CEP decoding failure count is increased, and if the CEP decoding failure count is greater than or equal to n, the wireless power receiver 650 reports that it has been removed from the charging area and transmits wireless power through the primary coil 605. Can be stopped.

The wireless power receiving device 650 is detachable from the wireless power transmitting device 600, and when the wireless power receiving device 650 is in the charging area of the wireless power transmitting device 600, the wireless power receiving device 650 It has at least one secondary coil 655 coupled with the generated electromagnetic field. In this way, power can be transferred from the wireless power transmitter 600 to the wireless power receiver 650 without direct electrical contact. The wireless power receiving device is connected to the load 670, the secondary coil 655, and collects power and supplies power to the load 670 (power pick-up unit 660), a communication unit 680 ), And a control unit 690.

The communication unit 680 controls communication between the wireless power transmitter 600 and the wireless power receiver 650. For example, the communication unit 680 may perform communication with the wireless power transmission device 600 through the secondary coil 605. As another example, the communication unit 620 and the communication unit 680 may each include separate RF communication means, and the communication unit 680 communicates with the wireless power transmission device 600 through the RF communication means. You may.

The communication unit 680 may transmit the ID, configuration information, CEP, or end power transfer packet of the wireless power receiver 650 to the wireless power transmitter 600.

The control unit 690 performs a series of controls to ensure that wireless power of a level suitable for the wireless power receiving device 650 is received.

All of the functions described above may be performed by a processor such as a microprocessor, controller, microcontroller, or Application Specific Integrated Circuit (ASIC) according to software or program code coded to perform the function. The design, development and implementation of the code will be apparent to those skilled in the art based on the description of the present invention.

Although the present invention has been described above with reference to examples, those skilled in the art can practice various modifications and changes of the present invention without departing from the spirit and scope of the present invention. You will understand. Therefore, it will be said that the present invention is not limited to the above-described embodiment, and the present invention includes all embodiments within the scope of the following claims.

Claims (15)

In the wireless power transmission device for performing power control,
At least one primary coil for transmitting wireless power to the wireless power receiving device;
A communication unit that receives and decodes a signal including a control error packet (CEP) from the wireless power receiver through the primary coil; And
A control unit that drives a CEP timer to check whether the CEP is received within a predetermined time, and counts interrupts generated in decoding a signal received through the primary coil.
Including,
And the control unit controls wireless power transmission and interruption to the wireless power receiving device through the primary coil based on at least one of the count of the CEP timer and the interrupt. According to claim 1,
The control unit, the CEP timer expires, characterized in that when the interrupt count is not greater than the reference value, the wireless power transmission device, characterized in that for stopping the wireless power transmission. According to claim 2,
The control unit is characterized in that the CEP timer expires, and if the interrupt count is greater than a reference value, the wireless power transmission is continued and the CEP timer is initialized. According to claim 1,
And the control unit increases the CEP decoding failure count when the CEP timer expires and the interrupt count is not greater than a reference value. According to claim 4,
And the control unit continues the wireless power transmission and initializes the CEP timer when the CEP decoding failure count is less than n. The method of claim 5,
And the control unit stops the wireless power transmission when the CEP decoding failure count is greater than or equal to n. The method of claim 6,
The reference value is 100, characterized in that the n = 5, a wireless power transmission device. In the wireless power transmission method by a wireless power transmission device for performing power control,
Transmitting wireless power to the wireless power receiving device through at least one primary coil;
Receiving a signal including a control error packet (CEP) carrying power control-related information from the wireless power receiver through the primary coil;
Driving a CEP timer to check whether the CEP is received within a predetermined time;
Counting interrupts occurring in decoding a signal received through the primary coil; And
Controlling wireless power transmission and interruption to the wireless power receiving device through the primary coil based on at least one of the CEP timer and the count of the interrupt.
Including, wireless power transmission method. The method of claim 8,
When the CEP timer expires and the count of the interrupt is not greater than a reference value, the wireless power transmission method is stopped. The method of claim 9,
When the CEP timer expires and the interrupt count is greater than a reference value, the wireless power transmission method is characterized in that the wireless power transmission is continued. The method of claim 10,
And when the CEP timer expires and the interrupt count is greater than a reference value, initializing the CEP timer. The method of claim 8,
And if the CEP timer expires and the interrupt count is not greater than a reference value, increasing the CEP decoding failure count. The method of claim 12,
And if the CEP decoding failure count is less than n, initializing the CEP timer. The method of claim 13,
When the CEP decoding failure count is greater than or equal to n, the wireless power transmission method is stopped. The method of claim 14,
The reference value is 100, characterized in that the n = 5, the wireless power transmission method.

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