KR20210014712A - Apparatus and method for detecting foreign object in wireless power transmitting system - Google Patents

Abstract

The present invention relates to an apparatus and a method for detecting foreign matter in a wireless power transmission system. The present invention provides a wireless power receiver for detecting foreign substances, which includes: a power measurement unit for generating required power information indicating the power required for the wireless power receiver, transmitting the requested power information to a wireless power transmitter, and measuring power derived from the wireless power transmitter; and an auxiliary coil for receiving power derived from the wireless power transmitter. According to the present invention, it is possible to prevent damage to the device by foreign substances by recognizing the foreign substances intervening between the wireless power transmitter and the wireless power receiver and allowing the user to remove the foreign substances.

Description

Foreign matter detection device and method in wireless power transmission system {APPARATUS AND METHOD FOR DETECTING FOREIGN OBJECT IN WIRELESS POWER TRANSMITTING SYSTEM}

The present invention relates to wireless power transmission, and more particularly, to an apparatus and method for detecting foreign matter in a wireless power transmission system.

In general, a battery pack is to supply power for operation of a portable terminal (cell phone, PDA, etc.) in a charged state by receiving power (electric energy) from an external charger, and a battery that charges electric energy. A circuit for charging and discharging the cell and the battery cell (supplying electric energy to a portable terminal) is configured.

In the electrical connection method between the charger and the battery pack for charging electric energy to the battery pack used in such a portable terminal, the battery pack is supplied with commercial power and converted into voltage and current corresponding to the battery pack. There is a terminal supply method that supplies electrical energy.

However, such a terminal supply method has problems such as instantaneous discharge phenomenon due to different potential differences between terminals, burnout and fire occurrence, natural discharge, and deterioration of the life and performance of the battery pack.

Recently, in order to solve the above problem, a contactless charging system and control method using a wireless power transmission method have been proposed.

The contactless charging system as described above includes a contactless power transmission device for supplying electric energy through a wireless power transmission method, and a contactless power for charging battery cells by receiving electric energy supplied from the contactless power transmission device. It consists of a receiving device and the like.

On the other hand, the contactless charging system as described above is charged while the contactless power receiving device is placed in the contactless power transmission device due to the characteristics of the contactless method.

At this time, when a foreign material such as metal is placed in the contactless power transmission device, power transmission may not be performed smoothly due to the foreign material, and problems such as damage to the product due to overload occurred.

An object of the present invention is to provide an apparatus and method for detecting foreign substances in a wireless power transmission system.

According to an aspect of the present invention, a power transmission path formed by self-resonant coupling between a primary coil provided in a wireless power transmission device and a secondary coil provided in a wireless power receiving device In the wireless power transmission method performed in the wireless power transmission device of the wireless power transmission system comprising a, the method receives first control information on the desired power (desired power) of the wireless power receiver through a communication path Step to do; Generating wireless power based on the control information, and transmitting the wireless power to the wireless power receiver by the magnetic resonance coupling; Receiving second control information on the wireless power measured by the wireless power receiving device through the communication path; And performing power control on the wireless power based on the first control information and the second control information.

According to another aspect of the present invention, there is provided a wireless power receiver for detecting foreign substances. The device may include a first coil provided in the wireless power transmission device and a second coil forming a magnetic resonance coupling; And a measuring unit that transmits first control information on the desired power of the wireless power receiver to the wireless power transmission device through a communication path, wherein the second coil is the control information The wireless power generated based on is received by the self-resonant coupling, and the measuring unit measures the amount of power of the received wireless power, and the wireless power is based on the first control information and the second control information. The second control information on the measured wireless power so that power control is performed by the transmission device is transmitted to the wireless power transmission device through the communication path.

According to another aspect of the present invention, there is provided a method for receiving wireless power by a wireless power receiving device for detecting foreign substances. The method includes a power transmission path formed by self-resonant coupling between a first coil provided in the wireless power transmission device and a second coil provided in the wireless power receiving device. In the wireless power reception method performed by the wireless power reception device of a transmission system, the step of transmitting first control information on the desired power of the wireless power reception device to the wireless power transmission device through a communication path ; Receiving wireless power generated based on the control information by the magnetic resonance coupling; Measuring the amount of power of the received wireless power and transmitting second control information on the measured wireless power to the wireless power transmission device through the communication path; And performing power control in the wireless power transmission device based on the first control information and the second control information.

According to another aspect of the present invention, a wireless power transmission device for detecting foreign matter is provided. The apparatus may include a first coil forming a magnetic resonance coupling with a second coil provided in the wireless power receiving apparatus; And a control unit that receives first control information about the desired power of the wireless power receiver through a communication path, wherein the first coil is a radio generated based on the control information. Power is transmitted to the second coil by the magnetic resonance coupling, and the control unit receives second control information on the wireless power measured by the wireless power receiver through the communication path, Power control for the wireless power is performed based on the first control information and the second control information.

The control unit may receive a reception power measurement result obtained by comparing and analyzing the wireless power measured by the wireless power receiving device and the requested power from the wireless power receiving device.

According to another aspect of the present invention, a wireless power transmission device for detecting foreign matter is provided. The device is a control unit that receives power demand information indicating power required for charging of the wireless power receiver from the wireless power receiver, generates a control signal for providing the requested power, and transmits it to an electric drive unit, the The electric drive unit for applying an electric drive signal to the main coil based on a control signal, the main coil connected to the electric drive unit and coupled to an auxiliary coil provided in the wireless power receiver to transmit wireless power, And a power measuring unit measuring wireless power generated by the main coil.

The control unit configures a generated power measurement report indicating the generated wireless power and transmits it to the wireless power receiving device, and compares the generated wireless power with the requested power and compares the received power measurement result to the wireless power. It can be received from the receiving device.

According to another aspect of the present invention, there is provided a wireless power transmission method using a wireless power transmission device for detecting foreign substances. The method comprises the steps of: receiving power demand information indicating power required for charging the wireless power receiver from the wireless power receiver, generating a control signal for providing the requested power to be provided with the wireless power transmitter Applying an electric driving signal to a coil, transmitting wireless power generated in the main coil due to the application of the electric driving signal to the wireless power receiving device having an auxiliary coil coupled to the main coil, and And receiving a reception power measurement result obtained by comparing and analyzing the wireless power measured by the wireless power receiver and the requested power from the wireless power receiver.

According to the present invention, by recognizing a foreign substance interposed between the wireless power transmission device and the wireless power receiving device and allowing the user to remove the foreign substance, damage to the device due to the foreign substance can be prevented.

1 illustrates the components of a wireless power transmission system according to an example of the present invention.
2 illustrates an example of a method of detecting a foreign matter by a wireless power receiver using the present invention.
3 illustrates an example of a method of detecting a foreign matter by a wireless power transmission device using the present invention.
4 illustrates another example of a method of detecting a foreign substance by a wireless power transmission device using the present invention.
5 illustrates components of a wireless power transmission system according to another example of the present invention.
6 illustrates components of a wireless power transmission system according to another example of the present invention.
7 illustrates another example of a method of detecting a foreign matter by a wireless power receiver using the present invention.
8 illustrates another example of a method of detecting a foreign substance by a wireless power transmission device using the present invention.
9 is a flowchart illustrating an operation between a wireless power transmitter and a wireless power receiver using the present invention.

The term "wireless power" used hereinafter is used to mean any form of energy related to an electric field, magnetic field, electromagnetic field, etc. transmitted from a transmitter to a receiver without the use of physical electromagnetic conductors. The wireless power may be referred to as a power signal, and may mean an oscillating magnetic flux enclosed by a main coil and a sub coil. Power conversion in a system is described herein to wirelessly charge devices including, for example, mobile phones, cordless phones, iPods, MP3 players, headsets, and the like. In general, the basic principle of wireless energy transfer includes, for example, a magnetic induction coupling method or a magnetic resonance coupling (ie, resonance induction) method using frequencies less than 30 MHz. However, various frequencies may be used, including those that allow license-exempt operation at relatively high radiation levels, for example less than 135 kHz (LF) or at 13.56 MHz (HF).

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

Referring to FIG. 1, a wireless power transmission system 1 includes a wireless power transmission device 10 and at least one wireless power reception device 30. The wireless power transmitter 10 has a primary coil 12 and an electric drive unit 14 connected to the main coil 12 to apply electric drive signals to the main coil to generate an electromagnetic field. . The control unit 16 is connected to the electric drive unit 14. This control unit 16 generates a control signal 106 that controls an AC signal required when the main coil 12 generates an induced magnetic field.

The wireless power transmitter 10 may have any suitable shape, but one preferred form is a flat platform with a power transmission surface, on which each wireless power receiver 30 will be placed on or near the platform. I can.

The wireless power receiver 30 is detachable from the wireless power transmitter 10, and is generated by the wireless power transmitter 10 when the wireless power receiver 30 is near the wireless power transmitter 10 It has a secondary coil (32) that is coupled to the electromagnetic field. In this manner, power can be transmitted from the wireless power transmitter 10 to the wireless power receiver 30 without direct electrical contact. In this case, it is said that the main coil 12 and the auxiliary coil 32 are magnetically inductively coupled or resonantly inductively coupled to each other.

The main coil 12 and auxiliary coil 32 may have any suitable shape, but may be copper wires wound around a high permeability formation such as ferrite or amorphous metal. The auxiliary coil 32 may have a single coil shape or a dual coil shape. Alternatively, the auxiliary coil 32 may include two or more coils.

The wireless power receiver 30 is usually connected to an external load (not shown, also referred to as an actual load of the wireless power receiver), and supplies the wireless power received from the wireless power transmitter 10 to an external load. The wireless power receiver 30 may be carried as a portable electric or electronic device or an object requesting power, such as a rechargeable battery or cell.

The wireless power receiver 30 of the wireless power transmission system 1 of FIG. 1 further includes a power measuring unit 31 connected to the auxiliary coil 32.

The power measurement unit 31 generates requested power information 33 indicating the power required by the wireless power receiver 30 and transmits it to the control unit 16. The required power information 33 is control information for controlling the wireless power to be supplied by the wireless power receiving device 30. The wireless power transmission system 1 of FIG. 1 supports a one-way communication method in which control information is transmitted only through a path from the wireless power receiver 30 to the wireless power transmitter 10.

As an example, the required power information 33 may numerically indicate an amount of power required by the wireless power receiver 30. For example, when the wireless power receiver 30 requires 10W of power, the power measurement unit 31 may generate the requested power information 33 indicating 10W.

The control unit 16 checks the required power information 33 and generates a control signal 106 so that the power indicated by the required power information 33 is generated. For example, when the requested power information 33 indicates 10W, the control unit 16 generates a control signal 106 so that 10W is transmitted. The electric drive unit 14 receives the control signal 106 to generate an inductive or resonant magnetic field in the vicinity of the main coil 12 and converts it into an AC current signal at the main coil 12.

The power measurement unit 31 measures wireless power (or received wireless power) transferred from the main coil 12 to the auxiliary coil 32 due to the AC current signal. The power measured by the power measurement unit 31 is calculated as the difference between the wireless power transmitted from the main coil 12 to the auxiliary coil 32 and other losses due to foreign substances such as parasitic loads around the system 1 Can be.

For example, it is assumed that 10W of wireless power is generated from the main coil 12 according to the required power information 33, transmitted to the auxiliary coil 32, and 2W of power is lost due to foreign substances. At this time, the power actually delivered to the auxiliary coil 32 (that is, the power actually received by the auxiliary coil 32) is 8W. The power actually received by the auxiliary coil 32 is called received power, and the received power is the total dissipated in the wireless power receiver due to the magnetic field generated by the wireless power transmitter. It is the amount of power.

The power measurement unit 31 transmits, to the control unit 16, a reception power measurement result 34 reporting the result of performing power measurement by comparing and analyzing the required power and the measured (or actually received) power. to provide.

As an embodiment, the power measurement unit 31 may represent a difference value between the requested power and the measured power as the received power measurement result 34. In this case, the reception power measurement result 34 indicates 2W.

As another embodiment, the power measurement unit 31 may represent the measured power value itself as the received power measurement result 34. In this case, the reception power measurement result 34 indicates 8W.

As another embodiment, the power measurement unit 31 may display the received power measurement result 34 in the form of a flag (0 or 1) indicating whether there is a difference between the requested power and the measured power. For example, if there is a difference between the required power and the measured power, the flag = 1, and if there is no difference, the flag = 0. Of course, the reverse is also possible. In the case of the above example, the reception power measurement result 34 indicates 1.

As another embodiment, the power measurement unit 31 may determine whether the difference between the requested power and the measured power is greater than or equal to or less than a threshold, and the result of this determination may be expressed as the received power measurement result 34. have. For example, if the difference between the required power and the measured power is greater than the threshold, the received power measurement result (34) = 1, and if the difference between the required power and the measured power is less than or equal to the threshold, the received power measurement result (34) = 0 Can be set to In the above example, if the threshold is 1W, the lost power 2W is greater than 1W, so the received power measurement result 34 indicates 1. If the difference between the required power and the measured power is greater than the threshold, this means that a foreign material has been detected, and thus the reception power measurement result 34 = 1 has the same meaning as the FOD (foreign object detection) declaration. For example, if the reception power measurement result (34) = 1 is continuously maintained for a predetermined period of time and does not change, it indicates that foreign matter is continuously present, so that the wireless power transmission device 10 can stop or block the wireless power transmission. have.

As another embodiment, if there is a difference between the required power and the measured power, the power measurement unit 31 has the same meaning as the FOD, and provides the received power measurement result 34 representing this to the control unit 16, If there is no difference, no signal may be provided to the control unit 16.

The control unit 16 receiving the received power measurement result 34 enters a cut-off mode in which the driving of the main coil 12 is reduced or stopped when it is determined that there is a significant parasitic load near the wireless power transmission device 10. Heat generation of parasitic load can be prevented. As a result, inefficient supply of induced power may be limited or stopped. This is when a foreign object is detected, the wireless power transmission device 10 takes action. Alternatively, the power measurement unit 31 may enter a cut-off mode in which the driving of the main coil 12 is reduced or stopped, thereby preventing heat generation of the parasitic load. This is when a foreign object is detected, the wireless power receiver 30 takes action.

In this way, the wireless power receiver 30 not only transmits signals to the wireless power transmitter 10, but also has a power measuring unit 31 to measure the power transmitted from the wireless power transmitter 10. And, a one-way power control technology for comparing the measured value with a power value requested by itself and transmitting the result to the wireless power transmission device 10 may be provided.

2 illustrates an example of a method of detecting a foreign matter by a wireless power receiver using the present invention.

Referring to FIG. 2, the wireless power receiver 30 generates requested power information indicating the power requested by the wireless power receiver 30 (S200).

The wireless power receiver 30 transmits the requested power information to the wireless power transmitter 10 (S205). When the wireless power transmitter 10 generates power in the main coil 12 according to the required power information, the wireless power receiver 30 uses the auxiliary coil 32 to generate magnetic induction or magnetic resonance. The wireless power based on magnetic resonance) is received from the wireless power transmitter 10 (S210).

The wireless power receiver 30 measures the wireless power received in response to the requested power information (S215). At this time, the measured power is the initial wireless power (or required power) transmitted from the wireless power transmitter 10 to the wireless power receiver 30 and other losses due to foreign substances such as parasitic loads present in the vicinity. It can be calculated as a difference.

The wireless power receiver 30 provides a reception power measurement result reporting a result of comparing and analyzing the required power and the measured power to the wireless power transmitter 10 (S225).

As an embodiment, the wireless power receiver 30 may represent a difference value between the requested power and the measured power as the received power measurement result 34.

As another embodiment, the wireless power receiver 30 may represent the measured power value itself as the received power measurement result 34.

As another embodiment, the wireless power receiver 30 may display a flag type (0 or 1) indicating whether there is a difference between the requested power and the measured power as a result of measuring the received power.

As another embodiment, the wireless power receiver 30 may determine whether a difference between the requested power and the measured power is greater than or equal to or less than a threshold, and the result of this determination may be expressed as a reception power measurement result.

As another embodiment, if there is a difference between the requested power and the measured power, the wireless power receiving device 30 provides the received power measurement result indicating this to the wireless power transmitting device 10. It may not be provided to the transmission device 10. In this case, step S225 may be omitted.

As another embodiment, the wireless power receiver 30 may determine whether the measured power is greater than or less than the required power, and may represent this as a result of measuring the received power. For example, the reception power measurement result may be expressed as'high' or'low'. 'High' indicates that the measured power is greater than the required power, and'low' indicates that the measured power is less than the required power. Alternatively, the reception power measurement result may be expressed in three states such as'high','low', or'equal'.

3 illustrates an example of a method of detecting a foreign matter by a wireless power transmission device using the present invention.

Referring to FIG. 3, the wireless power transmitter 10 receives requested power information from the wireless power receiver 30 (S300). According to the requested power indicated by the requested power information, the wireless power transmitter 10 transmits the wireless power to the wireless power receiver 30 based on a magnetic induction or magnetic resonance method (S305).

The wireless power transmission device 10 receives a reception power measurement result from the wireless power reception device 30, which reports a result of the actual measurement of the wireless power transmitted according to the required power by the wireless power reception device 30 (S310). ).

As a result of analyzing the reception power measurement result, if it is determined that a foreign substance has been detected, the wireless power transmitter 10 enters a cut-off mode in which the driving of the main coil 12 is reduced or stopped. As a result, heat generation of the parasitic load may be prevented, and supply of inefficient induced power may be limited or stopped.

4 illustrates another example of a method of detecting a foreign substance by a wireless power transmission device using the present invention.

4, steps S400 to S410 are performed in the same manner as steps S300 to S310, respectively. Meanwhile, step S410 may be limited by the following various embodiments.

As an example, in an embodiment in which the received power measurement result indicates whether the measured power is greater than or less than the required power (high) or less (low), the wireless power transmitter 10 indicates'low' or'high' It is determined whether the received power measurement result is continuously received N times in the same manner (S415). Here, N represents the number of consecutive “low” or “high” receptions required for the wireless power transmitter 10 to stop transmitting wireless power, and may be N=2. For example, if the received power measurement result indicating'low' is continuously received twice, the wireless power transmitter 10 may stop power transmission as a measure for detecting foreign substances (S420). . Conversely, even when the received power measurement result indicating'high' is continuously received twice, the wireless power transmission device 10 may stop power transmission as a measure for detecting foreign substances (S420).

On the other hand, when the reception power measurement result indicating'low' or'high' is continuously received less than two times, the wireless power transmission device 10 transmits the wireless power to the wireless power reception device 30 again ( S405). For example, if the reception power measurement result indicating'low' was previously received, but the reception power measurement result indicating'high' is currently received, the same reception power measurement result is not received twice in a row. Thus, in this case, the wireless power transmission device 10 does not stop the transmission of wireless power.

As another example, in an embodiment in which the received power measurement result indicates that there is a difference between the requested power and the measured power, the wireless power transmission device 10 continuously equally and continuously displays the received power measurement result indicating'there is a difference'. When receiving N times, the wireless power transmission device 10 may stop power transmission as a measure for detecting foreign substances (S420).

As another example, in an embodiment in which the received power measurement result is a result of determining whether the difference between the requested power and the measured power is greater than, equal to, or less than a threshold, the wireless power transmission device 10 is'large' or'small When the received power measurement result indicating'indicating 'is continuously received N times, the wireless power transmitter 10 may stop the transmission of wireless power as a measure for detecting foreign substances (S420).

5 illustrates components of a wireless power transmission system according to another example of the present invention.

Referring to FIG. 5, a wireless power transmission system 4 includes a wireless power transmission device 40 and at least one wireless power reception device 50. The wireless power transmitter 40 has a main coil 44, and an electric drive unit 43 connected to the main coil 44 to apply electric drive signals to the main coil 44 to generate an electromagnetic field. The control unit 42 is connected to the electric drive unit 43. This control unit 42 generates a control signal 45. The electric drive unit 43 receives the control signal 45 to generate an inductive or resonant magnetic field in the vicinity of the main coil 44 and converts it into an AC current signal at the main coil 44.

The wireless power transmitter 40 may have any suitable shape, but one preferred form is a flat platform with a power transmission surface, on which each wireless power receiver 50 will be placed on or near the platform. I can.

The wireless power receiving device 50 is detachable from the wireless power transmitting device 40, and is generated by the wireless power transmitting device 40 when the wireless power receiving device 50 is near the wireless power transmitting device 40 It has an auxiliary coil 52 coupled to the electromagnetic field. In this manner, power can be transferred from the wireless power transmitter 40 to the wireless power receiver 50 without direct electrical contact.

The main coil 44 and the auxiliary coil 52 may have any suitable shape, but may be copper wires wound around a high permeability formation such as ferrite or amorphous metal. The auxiliary coil 52 may have a single coil shape or a dual coil shape. Alternatively, the auxiliary coil 52 may include two or more coils.

The wireless power receiver 50 of the wireless power transmission system 4 of FIG. 5 further includes a secondary power measuring unit 51 connected to the auxiliary coil 52.

The auxiliary power measurement unit 51 generates requested power information 53 indicating the power required by the wireless power receiver 35 and transmits it to the control unit 42. The requested power information 53 is control information for controlling the power to be supplied by the wireless power receiver 50.

As an example, the required power information 53 may numerically indicate an amount of power required by the wireless power receiver 50. For example, when the wireless power receiver 50 requires 10W of power, the power measurement unit 51 may generate the requested power information 53 indicating 10W.

The control unit 42 checks the requested power information 53 and generates a control signal 45 so that the power indicated by the requested power information 53 is generated. For example, when the requested power information 53 indicates 10W, the control unit 42 generates a control signal 45 so that 10W is transmitted. The electric drive unit 43 receives the control signal 45 to generate an inductive or resonant magnetic field in the vicinity of the main coil 44 and converts it into an AC current signal at the main coil 44.

The wireless power transmitter 40 further includes a primary power measuring unit 41. The main power measurement unit 41 measures the power generated in the main coil 44 due to the AC current signal. For example, the requested power information 53 indicates 10W, but the actual generated power may be measured as 12W. That is, in order for the power actually received by the wireless power receiver 50 to be 10W as indicated by the requested power information 53, the main coil 44 generates 12W that is more than that. This can be seen as a 2W loss due to foreign substances such as parasitic loads existing around the system 4 in the process of transmitting wireless power from the main coil 44 to the auxiliary coil 52.

The control unit 42 configures (or generates) a measurement report of the generated power 54 indicating the generated power measured by the main power measurement unit 41, and the auxiliary power measurement unit 51 ). In this way, the wireless power transmission system 4 may transmit the control information 53 through a path from the wireless power receiving device 50 to the wireless power transmitting device 40, or receive wireless power from the wireless power transmitting device 40. A two-way communication method in which the control information 54 and 55 may be transmitted through a path to the device 50 is supported.

The auxiliary power measurement unit 51 compares and analyzes the difference between the power indicated by the generated power measurement report 54 and the required power, and determines whether to make a foreign matter detection declaration (FOD declaration).

As an embodiment, the auxiliary power measurement unit 51 determines whether the difference between the power indicated by the generated power measurement report 54 and the requested power is greater than, equal to, or less than a threshold, and measures the received power. It can be expressed as a measurement result (55). For example, if the difference between the power indicated by the generated power measurement report 54 and the required power is greater than the threshold value, the auxiliary power measurement unit 51 returns the received power measurement result 55 = 1, and the generated power measurement report 54 If the difference between the power indicated by) and the required power is less than or equal to the threshold value, the auxiliary power measurement unit 51 may set the received power measurement result 55 = 0. Alternatively, when the difference between the power indicated by the generated power measurement report 54 and the required power is greater than or equal to the threshold value, the auxiliary power measurement unit 51 returns the received power measurement result 55 = 1, and the generated power measurement report ( When the difference between the power indicated by 54) and the required power is less than the threshold value, the auxiliary power measurement unit 51 may set the received power measurement result 55 = 0. Of course, the values 0 and 1 of the reception power measurement result 55 indicate, respectively, may be interchanged with each other.

For example, let's say the threshold is 1W. As in the example above, in a situation where the power indicated by the generated power measurement report 54 is 12W and the required power is 10W, the difference is 2W, which is greater than the threshold value of 1W. In this case, the reception power measurement result 34 indicates 1. If the difference between the power indicated by the generated power measurement report 54 and the required power is greater than a threshold, this may mean that a foreign substance has been detected.

In the above, when the auxiliary power measurement unit 51 declares foreign matter detection, it has been described that the difference between the power indicated by the generated power measurement report 54 and the required power is compared and analyzed. However, the auxiliary power measurement unit 51 may compare and analyze the difference between the power indicated by the generated power measurement report 54 and the power actually received by the wireless power receiver 50 to declare a foreign matter detection. In this case, the method of comparison analysis may be performed in the same manner as the method of comparing and analyzing the difference between the power indicated by the generated power measurement report 54 and the required power.

If the wireless power transmission device 40 satisfies the required power by transmitting wireless power or excessive wireless power that is greater than a certain amount compared to the required power (or the power actually received by the wireless power receiver 50) due to a loss due to foreign matter In this case, it is desirable to stop or block power transmission by declaring FOD because this reduces wireless power efficiency. In this sense, the reception power measurement result (55)=1 may have the same meaning as the FOD declaration. For example, if the reception power measurement result (55) = 1 is continuously maintained for a predetermined period of time and does not change, it means that foreign substances are continuously present, and the wireless power transmission device 40 can stop or block the wireless power transmission. have.

The control unit 42 receiving the received power measurement result 55 enters a cut-off mode in which the driving of the main coil 44 is reduced or stopped when it is determined that there is a significant parasitic load near the wireless power transmission device 40. Heat generation of parasitic load can be prevented. As a result, inefficient supply of induced power may be limited or stopped. This is when a foreign object is detected, the wireless power transmission device 40 takes action. Alternatively, the auxiliary power measurement unit 51 enters a cut-off mode in which the driving of the main coil 44 is reduced or stopped, thereby preventing heat generation of the parasitic load. This is when the foreign matter is detected, the wireless power receiver 50 takes action.

As described above, in the present invention, the wireless power transmission device 40 does not only transmit wireless power to the wireless power receiver 50, but the control unit 42 transmits power generated or transmitted by the wireless power transmission device 40. It provides a two-way power control technology that transmits the indicated generated power measurement report to the wireless power receiver 50.

6 illustrates components of a wireless power transmission system according to another example of the present invention.

6, the wireless power transmission device 60 has the same components as the wireless power transmission device 10 of FIG. On the other hand, the wireless power receiver 70 only further includes a measuring coil 71 compared to the wireless power receiver 30 of FIG. 1, and the remaining components are the same. The power measuring unit 31 is connected to the measuring coil 71. The measuring coil 71 may be provided in a form surrounding the outer side of the auxiliary coil 52 or may be provided inside the auxiliary coil 52 in a form surrounding the inner side of the auxiliary coil 52.

When a magnetic field or current or voltage is primarily induced in the auxiliary coil 52 by magnetic induction or magnetic resonance between the main coil 12 and the auxiliary coil 52, the magnetic field or current is secondary to the measuring coil 71 Or the voltage is induced. The power measurement unit 31 may measure received wireless power by using a magnetic field or current or voltage secondary to the measurement coil 71.

In FIG. 6, an example in which the measuring coil 71 is additionally configured in the wireless power receiving device 60 of FIG. 1 has been described, but the measuring coil 71 is the same in the wireless power receiving device 50 of FIG. 5. Of course it may be included.

7 illustrates another example of a method of detecting a foreign substance by a wireless power receiver using the present invention.

Referring to FIG. 7, the wireless power receiver 50 generates requested power information indicating power requested by the wireless power receiver 50 (S700).

The wireless power receiver 50 transmits the requested power information to the wireless power transmitter 40 (S705). When the wireless power transmitter 40 generates power according to the requested power information, the wireless power receiver 50 receives the wireless power based on a magnetic or resonance induction method from the wireless power transmitter 40 (S710). .

The wireless power receiver 50 receives a generated power measurement report measuring the power generated by the wireless power transmitter 40 from the wireless power transmitter 40 (S715). Here, the power generated by the wireless power transmitter 40 does not involve other losses due to foreign substances, and may be different from the wireless power actually received by the wireless power receiver 50. For example, when other losses due to foreign substances are intervened, the wireless power actually received by the wireless power receiver 50 may be measured to be lower than the generated power.

The wireless power receiver 50 compares and analyzes the required power (or the actual received power) and the power indicated by the generated power measurement report to determine whether to make a foreign matter detection declaration (FOD declaration) (S720).

As an embodiment, the wireless power receiver 50 determines whether the difference between the power indicated by the generated power measurement report and the requested power is greater than or equal to or less than a threshold, and displays the result of this determination as a result of measuring the received power. I can. For example, if the difference between the power indicated by the generated power measurement report and the required power is greater than the threshold value, the wireless power receiver 50 receives the received power measurement result = 1, and the power and required power indicated by the generated power measurement report If the difference between them is less than or equal to the threshold, the wireless power receiver 50 may set the reception power measurement result = 0. Alternatively, when the difference between the power indicated by the generated power measurement report and the requested power is greater than or equal to the threshold value, the wireless power receiving device 50 receives the received power measurement result = 1, and the power and the request indicated by the generated power measurement report When the difference between the powers is less than the threshold value, the wireless power receiver 50 may set the reception power measurement result = 0. Of course, the values 0 and 1 of the received power measurement result indicate may be interchanged.

For example, let's say the threshold is 1W. As in the above example, in a situation where the power indicated by the generated power measurement report is 12W and the required power is 10W, the difference is 2W, which is greater than the threshold value of 1W. In this case, the reception power measurement result indicates 1. If the difference between the power indicated by the generated power measurement report and the required power is greater than the threshold, this may mean that a foreign substance has been detected.

The wireless power receiver 50 transmits the received power measurement result reporting the result of the comparative analysis to the wireless power transmitter 40 (S725).

8 illustrates another example of a method of detecting a foreign substance by a wireless power transmission device using the present invention.

Referring to FIG. 8, the wireless power transmitter 40 receives requested power information from the wireless power receiver 50 (S800). In accordance with the required power indicated by the required power information, the wireless power transmitter 40 generates wireless power based on a magnetic induction method. That is, the wireless power transmitter 40 checks the requested power information and generates a control signal so that the power indicated by the requested power information is induced. For example, when the requested power information indicates 10W, the wireless power transmission device 40 generates a control signal so that 10W is transmitted. The wireless power transmitter 40 receives a control signal to generate an induced electromagnetic field in the vicinity of the main coil 44 and converts it into an AC current signal in the main coil 44.

The wireless power transmission device 40 transmits the generated wireless power to the wireless power reception device 50 (S805).

At this time, the wireless power transmitter 40 measures the power generated by the main coil 44 according to the AC current signal (S810). For example, the required power information indicates 10W, but the actual generated power may be measured as 12W. That is, in order to transmit 10W to the wireless power receiver according to the indication of the required power information, the main coil 44 generates 12W that is more than that. This can be seen as a 2W loss due to foreign substances such as parasitic loads in the process of transmitting wireless power from the main coil 44 to the auxiliary coil 52.

The wireless power transmission device 40 constructs a generated power measurement report indicating the measured generated power and transmits it to the wireless power reception device 50 (S815). In this way, control information may be transmitted from the wireless power transmission device 40 to the wireless power receiving device 50, or control information is transmitted through the path from the wireless power receiving device 50 to the wireless power transmission device 40. A two-way communication method that may be used becomes possible.

The wireless power transmitter 40 receives the received power measurement result, which is a result of comparing and analyzing the requested power (or actually received power) and the power indicated by the generated power measurement report, from the wireless power receiver 50 (S820). ).

The received power measurement result is information indicating whether the difference between the power indicated by the generated power measurement report and the requested power is greater than, equal to, or less than a threshold. For example, if the difference between the power indicated by the generated power measurement report and the requested power is greater than the threshold value, the auxiliary received power measurement result is set to = 1, and the difference between the power indicated by the generated power measurement report and the requested power is greater than the threshold. If it is less than or equal to, the reception power measurement result = 0 can be set. Or, conversely, when the difference between the power indicated by the generated power measurement report and the requested power is greater than or equal to the threshold, the received power measurement result is set to = 1, and the difference between the power indicated by the generated power measurement report and the required power is the threshold. When it is smaller, the reception power measurement result may be set to 0. Of course, the values 0 and 1 of the received power measurement result indicate may be interchanged.

For example, let's say the threshold is 1W. As in the above example, in a situation where the power indicated by the generated power measurement report is 12W and the required power is 10W, the difference is 2W, which is greater than the threshold value of 1W. In this case, the reception power measurement result indicates 1. If the difference between the power indicated by the generated power measurement report and the required power is greater than the threshold, this may mean that a foreign substance has been detected. Accordingly, the wireless power transmission device 40 may recognize this as a foreign matter detection declaration.

As a result of analyzing the reception power measurement result, if it is determined that a foreign material has been detected, the wireless power transmission device 40 performs a measure for detecting the foreign material (S825). For example, the wireless power transmission device 40 may enter a cut-off mode in which driving of the main coil 12 is reduced or stopped. As a result, heat generation of the parasitic load may be prevented, and supply of inefficient induced power may be limited or stopped.

9 is a flowchart illustrating an operation between a wireless power transmitter and a wireless power receiver using the present invention.

Referring to FIG. 9, the wireless power receiver generates requested power information indicating power required by the wireless power receiver (S900).

The wireless power receiver transmits the requested power information to the wireless power transmitter (S905). When the wireless power transmitter generates power from the main coil according to the required power information, the wireless power receiver uses the auxiliary coil to transmit wireless power based on magnetic induction or magnetic resonance. It is received from (S910).

The wireless power receiver measures the wireless power received in response to the requested power information (S915). The power measurement unit may measure the wireless power induced by the secondary coil, or the wireless power secondary induced by the measurement coil from the secondary coil. At this time, the measured power may be calculated as the difference between the initial wireless power (or required power) transmitted from the wireless power transmitter to the wireless power receiver and other losses due to foreign substances such as parasitic loads present in the vicinity. .

The wireless power receiver provides a reception power measurement result reporting a result of comparing and analyzing the requested power and the measured power to the wireless power transmitter (S920).

As an embodiment, the received power measurement result may be defined as a difference value between the required power and the measured power.

As another embodiment, the received power measurement result may be defined as the measured power value itself.

As another embodiment, the received power measurement result may be defined as a flag (0 or 1) indicating whether there is a difference between the requested power and the measured power.

As another embodiment, the received power measurement result may be defined as a result of determining whether a difference between the requested power and the measured power is greater than, equal to, or less than a threshold.

As another embodiment, the received power measurement result may be defined as information transmitted to the wireless power transmitter only when there is a difference between the required power and the measured power. That is, if there is no difference between the required power and the measured power, the received power measurement result is not transmitted to the wireless power transmitter. In this case, step S920 may be omitted.

As another embodiment, the reception power measurement result may be defined as a result of determining whether the measured power is greater than or less than the required power. For example, the reception power measurement result may be expressed as'high' or'low'. 'High' indicates that the measured power is greater than the required power, and'low' indicates that the measured power is less than the required power. Alternatively, the reception power measurement result may be expressed in three states such as'high','low', or'equal'.

As a result of analyzing the reception power measurement result, if it is determined that a foreign material has been detected, a measure for foreign material detection is performed (S925). For example, the wireless power transmitter enters a cut-off mode in which the driving of the main coil is reduced or stopped. As a result, heat generation of the parasitic load may be prevented, and supply of inefficient induced power may be limited or stopped.

Measures for the detection of foreign substances by the wireless power transmission device may include the following embodiments. As an example, in an embodiment in which the received power measurement result indicates whether the measured power is greater than or less than the required power (high) or less (low), the wireless power transmission device measures the received power indicating'low' or'high' It is determined whether the result has been continuously received N times. Here, N represents the number of consecutive “low” or “high” receptions required for the wireless power transmitter to stop transmitting wireless power, and may be N=2. For example, if the received power measurement result indicating “low” is continuously received twice, the wireless power transmitter may stop power transmission as a measure for detecting foreign substances. Conversely, even when the received power measurement result indicating “high” is continuously received twice, the wireless power transmitter may stop power transmission as a measure for detecting foreign substances.

On the other hand, if the reception power measurement result indicating'low' or'high' is continuously received less than two times, the wireless power transmission device does not regard foreign matter as being detected and transmits the wireless power to the wireless power receiver again. I can. For example, if the reception power measurement result indicating'low' was previously received, but the reception power measurement result indicating'high' is currently received, the same reception power measurement result is not received twice in a row. In this case, the wireless power transmission device does not stop the transmission of wireless power.

As another example, in an embodiment in which the received power measurement result indicates that there is a difference between the requested power and the measured power, when the received power measurement result indicating'there is a difference' is continuously received N times, wireless power The transmission device may stop power transmission as a measure against foreign matter detection.

As another example, in an embodiment in which the received power measurement result is a result of determining whether the difference between the requested power and the measured power is greater than, equal to, or less than a threshold, the wireless power transmission device indicates'greater' or'small'. In the case of continuously receiving the same received power measurement result N times, the wireless power transmission device may stop the transmission of wireless power as a measure for detecting foreign substances.

All of the above-described functions may be performed by a processor such as a microprocessor, a controller, a microcontroller, or an 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 with reference to the embodiments above, it is understood that those of ordinary skill in the art can variously modify and change the present invention without departing from the spirit and scope of the present invention. You can understand. Therefore, it is not limited to the above-described embodiments, and the present invention will be said to include all embodiments within the scope of the following claims.

Claims (7)

In the wireless power receiving device,
A second coil configured to receive wireless power from a first coil included in the wireless power transmission device; And
Power measurement circuit configured to transmit power information indicating an amount of power required by the wireless power receiving device to the wireless power transmitting device
Including,
The power measurement circuit of the wireless power receiving device is also:
Measuring one or more measured power values representing the amount of power received from the wireless power transmission device after transmitting power information representing the amount of power required;
Determining that a foreign object has been detected based on a comparison of the amount of power required and the one or more measured power values;
And in response to determining that the foreign matter has been detected, configured to inform the wireless power transmission device to stop or stop transmitting wireless power. The wireless power receiving apparatus according to claim 1, wherein the power measuring circuit is further configured to transmit an indication as to whether or not the foreign object has been detected to the wireless power transmitting apparatus. The method of claim 1, wherein the power measurement circuit further:
Determine a difference value based on a comparison of the amount of power required and the one or more measured power values for a predetermined time;
Configured to generate a received power measurement result based on a difference between the difference value and a threshold. The wireless power receiving apparatus according to claim 3, wherein the power measuring circuit is further configured to transmit the received power measurement result to the wireless power transmitting apparatus. The apparatus of claim 3, wherein the received power measurement result includes determining whether the difference value is greater than, equal to, or less than the threshold. The apparatus of claim 1, wherein the second coil is magnetically or resonantly coupled to the first coil. The method of claim 1,
Wherein the power measurement circuit is further configured to inform the wireless power transmission device to stop or stop the transmission of wireless power, wherein the power measurement circuit is configured to transmit a foreign object detection (FOD) declaration. That, wireless power receiving device.

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