WIRELESS POWER TRANSMITTER AND RECEIVER

A wireless power transmitter, which transfers wireless power to a wireless power receiver, according to an embodiment includes: an accommodation part configured to accommodate the wireless power receiver; a transfer coil configured to surround the accommodation part in the form of a solenoid; a shield unit configured to surround the transfer coil in the form of the solenoid; an electromagnet disposed on a lower end of the accommodation part to fix the wireless power receiver; and a control unit configured to determine whether to transfer the wireless power to the wireless power receiver through the transfer coil, wherein the control unit controls the electromagnet so that the wireless power receiver is separated from the accommodation part due to a release of attractive force or repulsive force between the electromagnet and a metal body of the wireless power receiver when the wireless power is not transferred.

TECHNICAL FIELD

The present invention relates to a wireless power transmitter and a wireless power receiver.

BACKGROUND ART

Generally, various electronic equipment includes a battery and is driven by using power charged in the battery. Here, in the electronic equipment, the battery may be replaced and rechargeable. For this, the electronic equipment include a contact terminal coming into contact with an external charging device. That is, the electronic equipment is electrically connected to the charging device through the contact terminal. However, since the contact terminal of the electronic equipment is exposed to the outside, the contact terminal may be contaminated by foreign objects or short-circuited by moisture. In this case, contact failure may occur between the contact terminal and the charging device, and thus, the battery may not be charged in the electronic equipment.

To solve the above-described problem, a wireless power transfer (WPT) for wirelessly charging the electronic equipment has been proposed.

A wireless power transfer system is a technology that transfers power without a line through a space and maximizes convenience of power supply to mobile devices and digital household appliances.

The wireless power transfer system has advantages such as saving energy through real-time power usage control, overcoming a space limitation of the power supply, and reducing waste battery discharge through the recharging of the battery.

As a method for implementing the wireless power transfer system, there are typically a magnetic induction method and a magnetic resonance method. The magnetic induction method is a noncontact energy transfer technique in which two coils are close to each other, and current flows to one coil, and thus, electromotive force is generated in the other oil by using a magnetic flux generated thereby as a medium. Here, frequency of several hundred KHz may be used. The magnetic resonance method is a magnetic resonance technique that uses only electric fields or magnetic fields without using electromagnetic waves or current. Thus, a distance over which power is capable of being transferred may be several meters or more, and a band of several MHz may be used.

The wireless power transfer system includes a transfer device wirelessly transferring power and a receiver device receiving power to charge a load such as a battery. Here, a charging method of the receiver device, i.e., one charging method of the magnetic induction method or the magnetic resonance method may be selected, and a power transfer device for wirelessly transferring power to correspond to the charging method of the receiver device is being developed.

DISCLOSURE OF THE INVENTION

Technical Problem

A wireless power transfer device and a wireless power receiver device according to an embodiment are provided with a transfer coil having a sufficient thickness, a receiver coil having a sufficient thickness, and a shield part having a sufficient thickness.

A wireless power transfer device and a wireless power receiver device according to an embodiment wirelessly transfer and receive power by using a narrow area.

In a wireless power transfer device and a wireless power receiver device according to an embodiment, when transferring and receiving wireless power, the wireless power transfer device and the wireless power receiver device are coupled to each other.

In a wireless power transfer device and a wireless power receiver device according to an embodiment, when transferring and receiving of wireless power are ended, the wireless power transfer device and the wireless power receiver device are separated from each other.

Technical Solution

A wireless power transmitter, which transfers wireless power to a wireless power receiver, according to an embodiment includes: an accommodation part configured to accommodate the wireless power receiver; a transfer coil configured to surround the accommodation part in the form of a solenoid; a shield unit configured to surround the transfer coil in the form of the solenoid; an electromagnet disposed on a lower end of the accommodation part to fix the wireless power receiver; and a control unit configured to determine whether to transfer the wireless power to the wireless power receiver through the transfer coil, wherein the control unit controls the electromagnet so that the wireless power receiver is separated from the accommodation part due to a release of attractive force or repulsive force between the electromagnet and a metal body of the wireless power receiver when the wireless power is not transferred.

A wireless power receiver, which receives wireless power to a wireless power transmitter, according to an embodiment includes: a receiver coil configured to surround a core in the form of a solenoid; and a metal body disposed on a lower end of the core, wherein, when the receiver coil does not receive the wireless power, the metal body separates the wireless power receiver from the wireless power transmitter due to a release of attractive force or repulsive force between an electromagnet of the wireless power transmitter and a magnetic body.

A method for operating a wireless power transmitter according to an embodiment includes: being in standby state; transmitting and receiving a ping signal to and from a wireless power receiver; identifying the wireless power receiver; transferring wireless power to the wireless power receiver; and ending the wireless power transfer, wherein the identifying of the wireless power receiver includes recognizing that the wireless power receiver is inserted into an accommodation part of the wireless power transfer unit, and the ending of the wireless power transfer includes controlling the electromagnet so that the wireless power receiver is separated from the accommodation part due to a release of attractive force or repulsive force between an electromagnet and a metal body of the wireless power receiver.

A method for operating a wireless power receiver according to an embodiment includes: transmitting information for identifying the wireless power receiver to a wireless power transmitter; fixing the wireless power receiver to the wireless power transmitter by attractive force between an electromagnet of the wireless power transmitter and a metal body of the wireless power receiver; receiving wireless power from the wireless power transmitter: transmitting information for informing that charging is completed with respect to a battery of the wireless power receiver to the wireless power transmitter; and separating the wireless power transmitter from the wireless power receiver due to release of the attractive force or the repulsive force between the electromagnet of the wireless power transmitter and the metal body of the wireless power receiver.

Advantageous Effects

The wireless power transfer device and the wireless power receiver device according to the embodiment may be provided with the transfer coil having the sufficient thickness, the receiver coil having the sufficient thickness, and the shield part having the sufficient thickness to improve the wireless power transferring and receiving efficiency.

The wireless power transfer device and the wireless power receiver device according to the embodiment may wirelessly transfer and receive the power by using the narrow area. Thus, the wireless power may be transferred and received even the area that is less than the predetermined area for transferring and receiving the wireless power.

In the wireless power transfer device and the wireless power receiver device according to the embodiment when transferring and receiving wireless power the wireless power transfer device and the wireless power receiver device may be coupled to each other to improve the wireless power transferring and receiving efficiency and also stably transfer and receive the wireless power.

In the wireless power transfer device and the wireless power receiver device according to the embodiment, when the transferring and receiving of the wireless power are ended, the wireless power transfer device and the wireless power receiver device may be separated from each other to improve the wireless power transferring and receiving efficiency and also stably transfer and receive the wireless power.

MODE FOR CARRYING OUT THE INVENTION

Hereinafter, a coil device according to an embodiment, a method for manufacturing the coil device, and a wireless power transfer device and a wireless power receiver device including the coil device will be described in detail with reference to the accompanying drawings. The following embodiments are provided as mere examples to sufficiently express the ideas of the present invention to the skilled in the art. The prevent invention may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. In the drawings, the size and thickness of the device may be exaggerated for convenience. Like reference numerals designate like elements throughout the specification.

The embodiments may include a communication system that selectively uses various frequency bands ranging from a lower frequency (50 KHz) to a high frequency (15 MHz) to wirelessly transmit power and is capable of exchanging data and a control signal to control the system.

The embodiments may be applied to various industrial fields such as mobile terminal industries using electronic equipment in which a battery is used or required, smart clock industries, computer and notebook industries, household appliance industries, medical device industries, robot industries, and the like.

The embodiments may consider a system capable of transferring power to one or more plural devices by using one or a plurality of transfer coils.

According to the embodiments, the battery shortage problem in the mobile devices such as smart phones and notebooks may be solved. For example, when a wireless charging pad is placed on a table, and a smart phone or a notebook is used on the table, the battery may be automatically charged and thus be used for a long time. When the wireless charging pad is installed on public places such as cafeterias, airports, taxis, offices, restaurants, and the like, various mobile devices may be charged regardless of charging terminals which are different from each other according to the manufactures of the mobile devices. Also, when the wireless power transfer technology is applied to the household electrical appliances such as cleaners, electric fans, and the like, there is no need to look for power cables, and complex wires may be disappeared in the home. Therefore, wires within buildings may be reduced, and space utilization may be improved. When electric vehicles are charged by using the current household power, a time taken to charge the electric vehicles may increase. However, if high power is transmitted to the electric vehicles through the wireless power transfer technology, the charging time may be reduced. In addition, when the wireless charging facility is installed on the floor of the parking lot, power cables around the electric vehicles may not be prepared.

The terms and abbreviations used in the embodiments are as follows.

Wireless power transfer system: means a system providing wireless power transfer within a magnetic field area.

Wireless power transfer system-charger; power transfer unit (PTU): called a transfer device, a wireless power transmitter, or a transmitter as a device for managing an entire system, which wirelessly transfers power to the wireless power receiver device within magnetic fields.

Wireless power receiver system-device; power receiver unit (PRU): called a receiver device, a wireless power receiver, or a receiver as a device for wirelessly receiving power from the wireless power transfer device within magnetic fields.

Charging area: an area in which wireless power transfer is performed within a magnetic field area and which varies depending on a size, required power, and an operation frequency of an application product.

Scattering parameter: S parameter is a ratio (transmission; S21) of an input port to an output port or a self-reflection value of each of the input/output ports, i.e., an output value (reflection; Sri and Sm) reflected back from its input in terms of a ratio of an input voltage to an output voltage on a frequency distribution.

Quality factor: a value of Q in resonance means quality of frequency selection. The hinger the Q value, the better the resonance characteristics. The Q value is expressed as a ratio of energy stored in a resonator to lost energy.

Typically, there are a magnetic induction method and a magnetic resonance method as a method for wirelessly transferring power.

The magnetic induction method is a noncontact energy transfer technique in which electromotive force is generated in a load inductor Llby using a magnetic flux, which is generated when source inductors Lsare close to each other, and current is supplied to one of the source inductors Ls, as a medium. Also, the magnetic resonance method combines two resonators to generate magnetic resonance by a natural frequency between the two resonators and wirelessly transmits energy by using a resonance technique in which the resonators vibrate at the same frequency to form electric fields and magnetic fields in the same wavelength range.

FIG. 1is a view of a coil and a shield part of each of a wireless power transmitter and a wireless power receiver.

Referring toFIG. 1, a wireless power transfer device110may include a flat transfer coil111and a flat shield part112for shielding magnetic fields of the transfer coil111. Similarly, a wireless power receiver device120may include a flat receiver coil121and a flat shield part122for shielding magnetic fields of the receiver coil121.

Users prefer thin wireless power transfer devices or wireless power receiver devices. Thus, in the wireless power transfer device110including the flat transfer coil111and the flat shield part112, it may be difficult to mount the transfer coil having a sufficient thickness and the shield part having a sufficient thickness. Similarly, in the wireless power receiver device120including the flat receiver coil121and the flat shield part122, it may be difficult to mount the receiver coil having a sufficient thickness and the shield part having a sufficient thickness.

Also, in the wireless power transfer device110including the flat transfer coil111and the flat shield part112and the wireless power receiver device120including the flat receiver coil121and the flat shield part122, since the coil is wound in a flat shape, an area occupied by the coil and the shield may increase.

In addition, in the wireless power transfer device and the wireless power receiver device, each of which is provided with the flat coil and the flat shield part, when a distance d between the transfer coil and the receiver coil is 5 mm or more, charging efficiency may be significantly deteriorated.

Thus, a wireless power transfer device and a wireless power receiver device, each of which has a new structure for solving the problems of the wireless power transfer device and the wireless power receiver device, each of which is provided with the flat coil and the flat shield part, may be required.

FIG. 2is an equivalent circuit diagram of the wireless power transmitter and the wireless power receiver, which use a magnetic induction method.

Referring toFIG. 2, a transfer device210may include a source voltage Vs, a source resistor Rs, a source capacitor Csfor impedance matching, and a source coil Lsfor magnetic coupling with a receiver device according to devices for supplying power. The receiver device220may include a load resistor Rlthat is an equivalent load of the receiver unit, a load capacitor Clfor impedance matching, and a load coil Llfor magnetic coupling with the transfer device. A degree of the magnetic coupling of the source coil Lsand the load coil Llmay be represented by a mutual inductance Msl.

InFIG. 2, a ratio S21of the input voltage to the output voltage is obtained from the magnetic induction equivalent circuit constituted by only the coil without the source capacitor Csand the load capacitor Ce for the impedance matching. When a maximum power transfer condition is found from the ratio S21, the maximum power transfer condition satisfies the following Expression 1.

The maximum power transfer is possible when the ratio of the inductance of the transfer coil Lsto the source resistor Rsand the ratio of the inductance of the load coil Llto the load resistor Rlare the same. In a system with only an inductance, since there is no capacitor capable of compensating for reactance, a value of the self-reflection value S11of each of the input/output ports may not be zero at a point at which the maximum power transfer occurs. Also, power transfer efficiency may significantly vary depending on the value of mutual inductance Msl. Thus, the source capacitor Csmay be added to the transfer device210as a compensation capacitor for the impedance matching. In addition, the load capacitor Clmay be applied to the receiver device220. For example, the compensation capacitors Csand Clmay be connected to the receiver coil Lsand the load coil Llin series or parallel to each other, respectively. Also, an additional capacitor and a passive element such as an inductor may be further added to the transfer device210and the receiver device220for the impedance matching, respectively.

FIG. 3is a block diagram of the transfer device as one of a sub system constituting the wireless power transfer system according to an embodiment.

Referring toFIG. 3, a wireless power transmitter310according to an embodiment may include a power conversion unit311, a transfer coil unit312, and a control and communication unit313.

The power conversion unit311may power-convert an inputted DC or AC signal to output an AC signal. The transfer coil unit312may generate magnetic fields on the basis of the AC signal outputted from the power conversion unit311to transfer the power to the wireless power receiver device320within a charging area. The control and communication unit313may control the power conversion of the power conversion unit311and the transfer coil unit312. The control and communication unit313may adjust an amplitude and frequency of an output signal of the power conversion unit311. The control and communication unit313may sense at least one of an impedance, a voltage, and current from the power conversion unit311and the transfer coil unit312. The control and communication unit313may perform the wireless communication in an in-band method or an out-of-band method. The communication and control unit313may include a control part313-1and a communication part313-2. According to another embodiment, the communication and control unit313may be divided into a control part313-1and a communication part313-2.

The power conversion unit311may be called an inverter. The power conversion unit311may include at least one of a power conversion part that converts an AC signal into a DC, a power conversion part that outputs a DC by changing a level of the DC, and a power conversion part that converts DC into AC. Also, the transfer coil unit312may include a coil and an impedance matching part that resonant with the coil. Also, the control and communication unit313may include a sensing part (not shown) for sensing impedance, voltage, and current information.

FIG. 4is a block diagram of a transfer device as one of a sub system constituting a wireless power transfer system according to another embodiment.

Referring toFIG. 4, the transfer device410may include an inverter411, a coil selection unit412, a transfer coil unit413, a current detection unit414, and a control and communication unit415.

The inverter411may receive power from the power supply device (not shown). The inverter411may convert the DC signal inputted from the power supply device into the AC signal and adjust a frequency of the converted AC signal. For example, the inverter11may be a half bridge inverter or a full bridge inverter. Also, various amplifiers that convert DC into AC may be applied to the wireless power transfer system. For example, A-class, B-class, AB-class, C-class, E-class, and F-class amplifiers may be applied. Also, the inverter411may include an oscillator for generating a frequency of the output signal and a power amplifier for amplifying the output signal. The inverter411may be called a power conversion unit.

The coil selection unit412may select at least one coil for wirelessly transferring the power among the plurality of coils provided in the transfer coil unit413. According to another embodiment, the transfer coil unit413may include one coil.

The transfer coil unit413may include a plurality coils. The plurality of coils may be spaced apart from each other or overlap each other. When the plurality of coils overlap each other, an overlapping area may be determined in consideration of a deviation in magnetic flux density. Also, when the transfer coil unit413is manufactured, the transfer coil unit413may be manufactured in consideration of internal resistance and radiation resistance. Here, if the resistance component of the transfer coil unit413is low, a quality factor may increase, and transfer efficiency may be improved.

The current detection unit414may detect current generated from the transfer coil unit413. That is, the current detection unit414may detect whether the transfer coil unit413transfers the wireless power. Also, the current detection unit414may transmit information for informing whether the transfer coil unit413transfers the wireless power to the control and communication unit415.

The control and communication unit415may be called a microprocessor, a micro controller unit (MCU), or a micom. The control and communication unit415may perform communication with the receiver device. For example, the control and communication unit415may perform the communication through a short distance communication method such as Bluetooth, NFC, Zigbee, and the like. The control and communication unit415and the receiver device may transmit and receive charging status information and a charging control command to and from each other. The charging status information may include the number of wireless power receiver device, a battery remaining amount, the number of times of charging, an amount of usage, a battery capacity, a battery ratio, and a transfer power amount of the transfer device410. Also, the control and communication unit415may transmit a charging function control signal for controlling a charging function of the receiver device. The charging function control signal may be a control signal that controls the wireless power transfer device to enable to disable the charging function.

FIG. 5is a block diagram of the receiver unit as one of the sub system constituting the wireless power transfer system according to an embodiment.

According to an embodiment, the wireless power transfer device520may be called a wireless power receiver, a receiver device, or a receiver.

Referring toFIG. 5, the wireless power transfer system according to an embodiment may include a transfer device510and a receiver device520wirelessly receiving power from the transfer device510. The receiver device520may include a receiver coil unit521, a power conversion unit522, and a control and communication unit524.

The receiver coil unit521may receive an AC signal transmitted from the transfer device510. The power conversion unit522may convert the AC power from the receiver coil unit521to output a DC signal. The power conversion unit522may include a power conversion part that converts an AC signal into DC, a power conversion part that outputs the DC by changing a level of the DC, and a power conversion part that converts DC into AC. According to another embodiment, the power conversion unit522may be separately provided from the receiver device520.

The control and communication unit523may sense a current voltage of the receiver coil unit521. The control and communication unit523may control power conversion of the power conversion unit522. The control and communication unit523may adjust a level of the output signal of the power conversion unit522. The control and communication unit523may sense an input or output voltage or current of the power conversion unit522. The control and communication unit523may control whether the output signal of the receiver-side power conversion unit522is transmitted to the load524. The control and communication unit523may be divided into a control part523-1and a communication part523-2.

The load524may receive the DC signal outputted) from the conversion unit (522than be charged. The load524may include a battery524-1and a battery management part524-2. The battery management part524-2may detect a charged state of the battery524-1to adjust a voltage and current applied to the battery524-1.

FIG. 6is a block diagram of a receiver unit device as one of a sub system constituting a wireless power transfer system according to another embodiment.

Referring toFIG. 6, a receiver device620according to another embodiment may include a receiver coil unit621, a power conversion unit622, a control and communication unit623, a load624, a communication modulator625, and an output release unit626. The power conversion unit622may be called a rectifying circuit part.

The receiver coil unit621may be disposed on the receiver device620together with a near field communication (NFC) antenna. The receiver coil unit621may have the same structure as the transfer coil unit621. A dimension of the NFC antenna may vary in electrical characteristic of the receiver device620.

The rectifying circuit unit622rectifies the AC signal output from the receiver coil unit621to generate a DC signal. An output voltage of the rectifying circuit unit622may be called a rectified voltage. The control and communication unit623may detect or change the output voltage of the rectifying circuit unit622. The rectifying circuit unit622may adjust a level of the DC signal to match a capacity of the load624.

The communication modulator625may modulate a signal transmitted from the control and communication unit623. The output release unit626may control the power supply to the load624. For example, the output release unit626may turn off a switch provided in the output release unit626under the control of the control and communication unit623when the power is not supplied to the load624.

The load624may include a battery, a display, a sound output circuit, a main processor, a battery management unit, and various sensors. The load624may include a battery and a battery management part.

The control and communication unit626may be activated by wake-up power received from the transfer device. The control and communication unit623may perform communication with the transfer device. The control and communication unit623may control an operation of the sub system of the receiver device620.

Also, referring to a relationship between the size of a signal and a frequency of the wireless power transfer system, in the case of the wireless power transfer using the magnetic induction method, the power conversion unit of the transfer device may receive an DC signal to output AC current having a frequency of KHz band (for example, 125 KHz). Also, the power conversion unit622of the receiver device620may receive an AC signal having a frequency of KHz band (for example, 125 KHz) to convert the received AC signal into a DC signal having several voltages to several ten voltages or several hundred voltages, thereby outputting the converted DC signal. For example, the power conversion unit622of the receiver device620may output a DC signal of 5 V that is adequate for the load624to transmit the outputted DC signal to the load624.

FIG. 7is a flowchart illustrating an operation of the wireless power transfer system, which is an operation flowchart based on an operation state of the wireless power transfer system according to an embodiment.

Referring toFIG. 7, the transfer unit according to an embodiment may have a standby state701, a digital ping state703, an identification state705, a power transfer state707, and an end state709of charge.

When power is applied to the transfer unit from the outside to drive the transfer unit, the transfer unit may become a standby state. The transfer unit that is in the standby state may detect whether an object disposed on the charging area (for example, the receiver unit or metallic foreign object (FO) exist.

The transfer unit may detect the object by monitoring a variation in magnetic flux, a variation in capacitance or inductance between the object and a transfer unit, or a shift in resonance frequency, but is not limited thereto.

When the transfer unit detects the object that is the receiver unit within the charging area, the standby state may proceed to the digital ping state that is the next process.

In the digital ping state, the transfer unit is connected to a chargeable receiver unit. Also, the transfer unit may confirm whether the receiver unit is in a state of an effective receiver unit that is chargeable with wireless power provided from the transfer unit. Also, the transfer unit may generate and output a digital ping having a predetermined frequency and timing so as to be connected to the chargeable receiver unit.

If a sufficient power signal for the digital ping is transmitted to the receiver unit, the receiver unit may respond to the digital ping by modulating the power signal according to a communication protocol. Also, when the transfer unit receives an effective signal from the receiver unit, the digital ping state may proceed to an identification state without removing the power signal. Also, if request of an end of charge (EOC) is received from the receiver unit, the transfer unit may proceed to the end state of charge.

In addition, when the effective receiver unit is not detected, or when the response time of the object for the digital ping exceeds a preset time, the transfer unit may return to the standby state by removing the power signal.

When the response of the receiver unit according to the digital ping of the transfer unit is completed, the transfer unit may transmit identification information of the transfer unit to the receiver unit to confirm compatibility between the transfer unit and the receiver. Also, when the compatibility is confirmed, the receiver unit may transmit the identification information to the transfer unit. Also, the transfer unit may confirm the identification information of the receiver unit.

When the mutual identification of the transfer unit is completed, the identification state may proceed to a power transfer state. If the identification state fails, or the identification time exceeds a predetermined identification time, the identification state may return to the standby state.

The communication and control unit of the transfer unit may control the transfer unit on the basis of control data received from the receiver unit to provide charging power to the receiver unit.

Furthermore, the transfer unit may verify whether the charging power is out of an appropriate operation range, or stability against the foreign object detection (FOD) is a problem.

Also, when the transfer unit receives the charge end signal from the receiver unit, or the operation range exceeds a predetermined limit temperature value, the transfer unit may stop the power transfer to proceed to the end state of charge.

Also, in the case of a situation where the power is not suitable for the transfer, the transfer unit may remove the power signal and return to the standby state. Also, the transfer unit enters the charging area again after the receiver unit is removed, the above-described cycle may proceed again.

Also, the transfer unit may return to the identification state again according to the charging state of the load of the receiver unit and provide the adjusted charging power to the receiver unit on the basis of the status information of the load.

When the transfer unit receives the information in which the charging is completed from the receiver unit or he receiver unit receives the information in which a temperature is risen above a preset temperature, the power transfer state may proceed to an end state of change.

When the transfer unit receives the charge completion information from the receiver unit, the transfer unit may stop the power transfer and then standby for a predetermined time. Also, the transfer unit may enter the digital ping state so as to be connected to the receiver unit located in the charging area the predetermined time has elapsed.

Also, the transfer unit may standby for the predetermined time when receiving information indicating that the preset temperature is exceeded from the receiver unit. Also, the transfer unit may enter the digital ping state so as to be connected to the receiver unit located in the charging area the predetermined time has elapsed.

Also, the transfer unit may monitor whether the receiver unit is removed from the charge area for a predetermined time. The transfer unit may return to the standby state when the receiver unit is removed from the charging area.

FIGS. 8A to 8Care cross-sectional views of the wireless power transmitter and the wireless power receiver according to an embodiment.

Referring toFIG. 8A, a wireless power receiver820may include a receiver coil surrounding a core823in the form of a solenoid. The core823may have a cylindrical shape or a hexahedral shape. For example, the core813may have a shape in which a cylinder, a prism, or a portion of a cylinder has a diameter that gradually increases or decreases. The receiver coil822may be disposed to surround the core823in a cylindrical or hexahedral structure according to the shape of the core823. For example, the receiver coil822may have a shape in which a cylinder, a prism, or a portion of a cylinder has a diameter that gradually increases or decreases.

The wireless power transmitter810may include an accommodation space813for accommodating the wireless power receiver820. The wireless power transmitter810may include a transfer coil821surrounding the accommodation space813in the form of a solenoid. The accommodation space813may have a cylindrical shape or a hexahedral shape. For example, the accommodation space813may have a shape in which a cylinder, a prism, or a portion of a cylinder has a diameter that gradually increases or decreases. The transfer coil812may be disposed to surround the accommodation space813in a cylindrical or hexahedral structure according to the shape of the accommodation space813. For example, the transfer coil812may have a shape in which a cylinder, a prism, or a portion of a cylinder has a diameter that gradually increases or decreases.

Referring toFIG. 8B, the wireless power receiver820may be inserted into the accommodation space813. The wireless power receiver820may transmit information for identifying the wireless power receiver820to the wireless power transmitter810. The wireless power transmitter810may receive information for identifying the wireless power receiver820from the wireless power receiver820. The wireless power transmitter810may identify the wireless power receiver820on the basis of the information for identifying the wireless power receiver820.

Referring toFIG. 8C, when the wireless power receiver820is identified, the wireless power transmitter810may transfer the wireless power to the receiver coil822through the transfer coil812. According to another embodiment, the wireless power transmitter810may detect the insertion of the wireless power receiver820into the accommodation space813without the information for identification. When the wireless power receiver820is inserted into the accommodation space813, the wireless power transmitter810may transfer the wireless power to the receiver coil822through the transfer coil812.

FIG. 9is a cross-sectional view of a wireless power transmitter and a wireless power receiver according to another embodiment.

Referring toFIG. 9, a wireless power receiver920may include a receiver coil922surrounding a core923in the form of a solenoid. The core923may have a cylindrical shape or a hexahedral shape. The receiver coil922may be disposed to surround the core923in a cylindrical or hexahedral structure according to the shape of the core923.

The wireless power transmitter910may include an accommodation space913for accommodating the wireless power receiver920. The wireless power transmitter910may include a transfer coil921surrounding the accommodation space913in the form of a solenoid. The accommodation space913may have a cylindrical shape or a hexahedral shape. The transfer coil912may be disposed to surround the accommodation space913in a cylindrical or hexahedral structure according to the shape of the accommodation space913.

The wireless power receiver920may be inserted into the accommodation space913. The wireless power receiver920may transmit information for identifying the wireless power receiver920to the wireless power transmitter910. The wireless power transmitter910may receive information for identifying the wireless power receiver920from the wireless power receiver920. The wireless power transmitter910may identify the wireless power receiver920on the basis of the information for identifying the wireless power receiver920.

When the wireless power receiver920is identified, the wireless power transmitter910may transfer the wireless power to the receiver coil922through the transfer coil912. According to another embodiment, the wireless power transmitter910may detect the insertion of the wireless power receiver920into the accommodation space913without the information for identification. When the wireless power receiver920is inserted into the accommodation space913, the wireless power transmitter910may transfer the wireless power to the receiver coil922through the transfer coil912.

The wireless power transmitter910may further include a shield part914. The shield part914may be disposed to surround the transfer coil912of the wireless power transmitter910. The shield part914may shield emission of electromagnetic fields, which are generated when the transfer coil912transfers the wireless power to the receiver coil922, to the outside.

FIG. 10is a view illustrating structures of a wireless power transmitter and a wireless power receiver according to further another embodiment.

Referring toFIG. 10, a wireless power receiver1020may include a receiver coil1022surrounding a core1023in the form of a solenoid. The core1023may have a cylindrical shape or a hexahedral shape. The receiver coil1022may be disposed to surround the core1023in a cylindrical or hexahedral structure according to the shape of the core1023.

The wireless power transmitter1010may include an accommodation space1013for accommodating the wireless power receiver1020. The wireless power transmitter1010may include a transfer coil1021surrounding the accommodation space1013in the form of a solenoid. The accommodation space1013may have a cylindrical shape or a hexahedral shape. The transfer coil1012may be disposed to surround the accommodation space1013in a cylindrical or hexahedral structure according to the shape of the accommodation space1013.

The wireless power receiver1020may be inserted into the accommodation space1013. The wireless power receiver1020may transmit information for identifying the wireless power receiver1020to the wireless power transmitter1010. The wireless power transmitter1010may receive information for identifying the wireless power receiver1020from the wireless power receiver1020. The wireless power transmitter1010may identify the wireless power receiver1020on the basis of the information for identifying the wireless power receiver1020.

When the wireless power receiver1020is identified, the wireless power transmitter1010may transfer the wireless power to the receiver coil1022through the transfer coil1012. According to another embodiment, the wireless power transmitter1010may detect the insertion of the wireless power receiver1020into the accommodation space1013without the information for identification. When the wireless power receiver1020is inserted into the accommodation space1013, the wireless power transmitter1010may transfer the wireless power to the receiver coil1022through the transfer coil1012.

The wireless power transmitter1010may further include a shield part1014. The shield part1014may be disposed to surround the transfer coil1012of the wireless power transmitter1010. The shield part1014may shield emission of electromagnetic fields, which are generated when the transfer coil1012transfers the wireless power to the receiver coil1022, to the outside.

According to an embodiment, the wireless power receiver1020may further include a metal body1024on a lower end of the core1023. The metal body1024may be a metal or magnet. According to another embodiment, the metal body1024may be disposed to be separated from the core1023.

According to an embodiment, the wireless power receiver1020may further include an electromagnet1015on a lower end of an accommodation space1013. The electromagnet1015may include pure iron and a coil that surrounds the pure iron in the form of a solenoid. The electromagnet1015may be a metal containing iron (Fe). Alternatively, the electromagnet1015may be a magnet.

FIG. 11is a cross-sectional perspective view of a wireless power transmitter and a wireless power receiver according to further another embodiment.

Referring toFIG. 11, a wireless power receiver1120may include a receiver coil1122surrounding a core1123in the form of a solenoid. The core1123may have a cylindrical shape or a hexahedral shape. The receiver coil1122may be disposed to surround the core1123in a cylindrical or hexahedral structure according to the shape of the core1123.

The wireless power transmitter1110may include an accommodation space1113for accommodating the wireless power receiver1120. The wireless power transmitter1110may include a transfer coil1121surrounding the accommodation space1113in the form of a solenoid. The accommodation space1113may have a cylindrical shape or a hexahedral shape. The transfer coil1112may be disposed to surround the accommodation space1113in a cylindrical or hexahedral structure according to the shape of the accommodation space1113.

The wireless power receiver1120may be inserted into the accommodation space1113. The wireless power receiver1120may transmit information for identifying the wireless power receiver1120to the wireless power transmitter1110. The wireless power transmitter1110may receive information for identifying the wireless power receiver1120from the wireless power receiver1120. The wireless power transmitter1110may identify the wireless power receiver1120on the basis of the information for identifying the wireless power receiver1120.

When the wireless power receiver1120is identified, the wireless power transmitter1110may transfer the wireless power to the receiver coil1122through the transfer coil1112. According to another embodiment, the wireless power transmitter1110may detect the insertion of the wireless power receiver1120into the accommodation space1113without the information for identification. When the wireless power receiver1120is inserted into the accommodation space1113, the wireless power transmitter1110may transfer the wireless power to the receiver coil1122through the transfer coil1112.

The wireless power transmitter1110may further include a shield part1114. The shield part1114may be disposed to surround the transfer coil1112of the wireless power transmitter1110. The shield part1114may shield emission of electromagnetic fields, which are generated when the transfer coil1112transfers the wireless power to the receiver coil1122, to the outside.

According to an embodiment, the wireless power receiver1120may further include a metal body1124on a lower end of the core1123. The metal body1124may be a metal or magnet. According to another embodiment, the metal body1124may be disposed to be separated from the core1123.

According to an embodiment, the wireless power receiver1120may further include an electromagnet1115on a lower end of an accommodation space1113. The electromagnet1115may include pure iron and a coil that surrounds the pure iron in the form of a solenoid. The electromagnet1115may be a metal containing iron (Fe). Alternatively, the electromagnet1115may be a magnet.

FIG. 12is a block diagram of the wireless power transmitter according to an embodiment.

Referring toFIG. 12, a wireless power transmitter1210according to an embodiment may include a transfer coil unit1211, a control unit1216, and a communication unit1217.

The transfer coil unit1211may include a transfer coil1212, a shield part1213, an electromagnet1214, and an accommodation part1215. The accommodation part1215may mean a space for accommodating the wireless power receiver. The transfer coil1212may be disposed to surround the accommodation part1215in the form of a solenoid. The shield part1213may shield magnetic fields generated by the transfer coil1212. The shield part1213may be disposed to surround the transfer coil1212in the form of the solenoid. The electromagnet1214may generate magnetic force for fixing or separating the wireless power receiver to and from the accommodation part1215. The electromagnet1214may be disposed on a lower end of the accommodation part.

The control unit may determine whether to transfer the wireless power to the wireless power receiver through the transfer coil1212. When the wireless power is not transferred, the control unit1216may control the electromagnet1214so that the wireless power receiver is separated from the accommodation part1215by release or repulsive force between the electromagnet1214and a metal body of the wireless power receiver. When the wireless power is transferred, the control unit1216may control the electromagnet1214so that the wireless power receiver is fixed due to attractive force between the electromagnet1214and the metal body.

When the wireless power is transferred, the control unit1216may apply a positive (+) voltage to the electromagnet1214. The electromagnet1214may generate the attractive force with respect to the metal boxy of the wireless power receiver through the applied positive voltage to fix the wireless power receiver to the accommodation part1215.

When the wireless power is not transferred, the positive voltage may not be applied to the electromagnet1214, or a negative (−) voltage may be applied to the electromagnet1214under the control of the control unit1216. When the negative voltage is applied, the electromagnet1214may generate the repulsive force with respect to the metal boxy of the wireless power receiver through the negative voltage to separate the wireless power receiver from the accommodation part1215.

The communication unit1217may receive information for identifying the wireless power receiver from the wireless power receiver. The communication unit1217may receive information on a charging state of the load of the wireless power receiver from the wireless power receiver.

The control unit1216may determine whether to transfer the wireless power to the wireless power receiver on the basis of the information on the charging state of the load of the wireless power receiver. The control unit1216may determine whether the wireless power receiver is inserted into the accommodation part1215. According to another embodiment, the control unit1216and the communication unit1217may be one device.

FIG. 13is a block diagram of the wireless power receiver according to an embodiment.

Referring toFIG. 13, the wireless power transmitter2700according to an embodiment may include a receiver coil unit1321, a control unit1325, a communication unit1326, and a load1327.

The receiver coil unit1321may include a core1323. The receiver coil unit1321may include a receiver coil1322surrounding a core1323in the form of a solenoid. The receiver coil unit1321may include a metal body disposed on a lower end of the core1323. The metal body1324may be a metal or magnet. According to another embodiment, the metal body1324may be provided in the core1323.

When the receiver coil1322does not receive the wireless power, the metal body1324may separate the wireless power receiver1320from the wireless power transmitter by using the release of the attractive force or the repulsive force between the metal body1324and the electromagnet of the wireless power transmitter. When the receiver coil1322receives the wireless power, the metal body1324may fix the wireless power receiver1320to the wireless power transmitter by using the attractive force between the metal body1324and the electromagnet of the wireless power transmitter.

The communication unit1326may transmit a signal for identifying the wireless power receiver1320to the wireless power transmitter. The load1327may store the wireless power received through the receiver coil1322. The control unit1325may determine the charging state of the load1327. The communication unit1326may transmit a signal for informing the charging state of the load1327to the wireless power transmitter. The wireless power receiver1320may be inserted into the accommodation space913of the wireless power transmitter.

FIG. 14is a flowchart illustrating an operation of the wireless power transmitter according to an embodiment.

Referring toFIG. 14, the wireless power transmitter may receive a ping signal from the wireless power receiver in a standby state (S1401step). For example, the wireless power transmitter may receive a signal for identifying the wireless power receiver from the wireless power receiver.

The wireless power transmitter may identify the wireless power receiver (S1402step). For example, the wireless power transmitter may identify the wireless power receiver on the basis of the information for identifying the wireless power receiver. According to an embodiment, the wireless power transmitter may determine whether the wireless power receiver is inserted into the accommodation part of the wireless power transmitter through the identification. According to another embodiment, the wireless power transmitter may determine whether the wireless power receiver is inserted into the accommodation part through the control unit without separate identification.

The wireless power transmitter may apply an AC voltage to an electromagnet of the wireless power transmitter (S1403step). The wireless power transmitter may apply a DC voltage of the electromagnet after the identifying the wireless power receiver. The wireless power transmitter may control the electromagnet so that attractive force is generated between the electromagnet of the wireless power transmitter and the metal body of the wireless power receiver to fix the wireless power receiver to the accommodation part of the wireless power transmitter. The electromagnet may generate the attractive force between the electromagnet and the metal body of the wireless power receiver by the applied DC voltage. The wireless power receiver may fix the wireless power receiver to the accommodation part of the wireless power transmitter by using the attractive force between the metal body and the electromagnet of the wireless power transmitter.

The wireless power transmitter may transfer and receive the wireless power to and from the wireless power receiver (S1404step). The wireless power transmitter may transfer the wireless power to the receiver coil of the wireless power receiver through the transfer coil.

The wireless power transmitter may end the wireless power receiver (S1405step). The wireless power transmitter may receive a signal for informing that the charging is completed with respect to the load of the wireless power receiver from the wireless power receiver. Alternatively, the wireless power transmitter may recognize that the wireless power receiver is out of a range in which the wireless power receiver is capable of receiving the wireless power.

The wireless power transmitter may release the DC voltage applied to the electromagnet (S1406step). Alternatively, the wireless power transmitter may apply a negative (−) DC voltage to the electromagnet.

The wireless power transmitter may apply a negative DC voltage of the electromagnet so that a repulsive force is generated between the electromagnet of the wireless power transmitter and the metal body of the wireless power receiver. The wireless power transmitter may separate the wireless power receiver from the accommodation part of the wireless power transmitter by using the repulsive force generated between the electromagnet and the metal body.

The wireless power transmitter may release the positive voltage applied to the electromagnet so that the repulsive force between the electromagnet of the wireless power transmitter and the metal body of the wireless power receiver is released. The wireless power transmitter may separate the wireless power receiver from the accommodation part of the wireless power transmitter by releasing the attractive force between the electromagnet and the metal body.

The wireless power transmitter may control the electromagnet so that the repulsive force is generated between the electromagnet of the wireless power transmitter and the metal body of the wireless power receiver to separate the wireless power receiver from the accommodation part of the wireless power transmitter. For example, the wireless power transmitter may apply the positive (+) voltage to the electromagnet to generate the attractive force between the electromagnet and the metal body of the wireless power receiver. The wireless power receiver may be fixed to the accommodation part of the wireless power transmitter by the generated attractive force.

FIG. 15is a flowchart illustrating an operation of the wireless power receiver according to an embodiment.

Referring toFIG. 15, the wireless power receiver may transmit a ping signal to the wireless power transmitter (S1501step). The ping signal may be a signal for identifying the wireless power receiver. For example, the wireless power receiver may transmit information for identifying the wireless power receiver to the wireless power transmitter.

The wireless power receiver may be identified to the wireless power transmitter (S1502step). For example, the wireless power receiver may be identified from the wireless power transmitter on the basis of the information for identifying the wireless power receiver.

The wireless power receiver may be fixed to the wireless power transmitter (S1503step). The wireless power receiver may be fixed to the wireless power transmitter by the attractive force between the electromagnet of the wireless power transmitter and the metal body of the wireless power receiver is released.

The wireless power receiver may receive the wireless power from the wireless power transmitter (S1504step). The wireless power receiver may receive the wireless power from the transfer coil of the wireless power transmitter through the receiver coil of the wireless power receiver.

The wireless power receiver may end the charging (S1505step). The wireless power receiver may transmit information for informing that the charging is completed with respect to the load of the wireless power receiver to the wireless power transmitter.

The wireless power receiver may be separated from the wireless power transmitter. The wireless power receiver may be separated from the wireless power transmitter due to the release of the attractive force or the repulsive force between the electromagnet of the wireless power transmitter and the metal body of the wireless power receiver.

INDUSTRIAL APPLICABILITY

Embodiments may be used in the wireless power transfer and receiver industries.