Patent Application
20180205265
This application claims benefit of priority to Korean Patent Application No. 10-2017-0008805 filed on Jan. 18, 2017 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety.
The present disclosure relates to a wireless power transmitter.
A wireless power transmitter compares a level of power transmitted by the wireless power transmitter with a level of power received by a wireless power receiver for foreign object detection (FOD). Such a foreign object detection method of comparing the power transmitted by the wireless power transmitter with the power received by the wireless power receiver is performed in a power transfer phase.
In a case in which a wireless power transmitter transmitting power having a low level, such as 5[W], detects a foreign object in the power transfer phase, a temperature increase rate may be low. However, in a case in which a recent wireless power transmitter transmitting power having a medium level, such as 15[W], detects a foreign object in the power transfer phase, since the temperature rapidly increases and the temperature increase rate is high, a user safety issue may result before the foreign object is detected or before a protection mode is entered into according to foreign object detection, and a shape of the wireless power transmitter/receiver may be deformed.
This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is this Summary intended to be used as an aid in determining the scope of the claimed subject matter.
In one general aspect, a wireless power transmitter includes: an inverter member including transistors configured to convert input power into alternating current (AC) power; a resonating member including a capacitor and a coil, and connected to an outer terminal of the inverter member; a controller configured to provide a switching signal to the plurality of transistors to control the inverter member; and a current limiting part configured to limit a level of a current applied to the inverter member by the input power.
The controller may be configured to determine a quality factor based on a minimum output voltage of the inverter member.
The controller may be configured to determine the quality factor based on a frequency of the switching signal corresponding to a point of time at which the minimum output voltage of the inverter member is detected.
The current limiting part may include a switch and a resistance element connected in parallel and disposed between the input power and the inverter member.
The controller may be configured to determine whether to enter into a power transfer phase based on the quality factor.
The controller may be configured to perform a control so that the switch performs an on-operation during the power transfer phase.
The resonating member may be configured to wirelessly generate power from the AC power during the power transfer phase.
Resistance of the resistance element may be determined based on a voltage of the input power.
In another general aspect, a wireless power transmitter operates by entering one of a plurality of phases according to a state of an external object, and the wireless power transmitter includes: an inverter member including transistors connected to input power in a half-bridge type or a full-bridge type; a resonating member including a capacitor and a coil, and connected to an output terminal of the inverter member; and a current limiting part configured to limit a level of a current applied to the inverter member by the input power during a ping phase of the phases.
The current limiting part may be configured to limit, during the ping phase, the level of the current applied to the inverter member by the input power and provide a reference level of current to the inverter member.
The current limiting part may be configured to transfer, during a power transfer phase of the phases, the current generated by the input power to the inverter member.
The level of the current applied to the inverter member during the ping phase may be lower than the level of the current applied to the inverter member during the power transfer phase.
Switching to the power transfer phase may be performed according to a quality factor detected during the ping phase.
The quality factor may be determined based on a minimum output voltage of the inverter member.
The quality factor may be determined based on a frequency of a switching signal provided to the plurality of transistors at a point of time at which a minimum output voltage of the inverter member is detected.
Either one or both of a type of an external object disposed to be adjacent to the coil and whether or not a center of the coil and the external object are aligned with each other may be determined according to the quality factor.
In another general aspect, a wireless power transmitter includes: an inverter member including transistors, and configured to convert input power into alternating current (AC) power; a resonating member including a capacitor and a coil, and connected to an outer terminal of the inverter member; a current limiting part including a switch and a resistance element connected in parallel, and configured to provide, using the input power, a lower level of current to the inverter member during a ping phase than a level of current provided during a power transfer phrase.
The ping phase may include a quality factor determination phase.
Other features and aspects will be apparent after an understanding of the following detailed description, drawings, and claims.
The above and other aspects, features and other advantages of the present disclosure will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:
The following detailed description is provided to assist the reader in gaining a comprehensive understanding of the methods, apparatuses, and/or systems described herein. However, various changes, modifications, and equivalents of the methods, apparatuses, and/or systems described herein will be apparent after an understanding of the disclosure of this application. For example, the sequences of operations described herein are merely examples, and are not limited to those set forth herein, but may be changed as will be apparent after an understanding of the disclosure of this application, with the exception of operations necessarily occurring in a certain order. Also, descriptions of features that are known in the art may be omitted for increased clarity and conciseness.
The features described herein may be embodied in different forms, and are not to be construed as being limited to the examples described herein. Rather, the examples described herein have been provided merely to illustrate some of the many possible ways of implementing the methods, apparatuses, and/or systems described herein that will be apparent after an understanding of the disclosure of this application.
Throughout the specification, when an element, such as a layer, region, or substrate, is described as being “on,” “connected to,” or “coupled to” another element, it may be directly “on,” “connected to,” or “coupled to” the other element, or there may be one or more other elements intervening therebetween. In contrast, when an element is described as being “directly on,”“directly connected to,” or “directly coupled to” another element, there can be no other elements intervening therebetween.
As used herein, the term “and/or” includes any one and any combination of any two or more of the associated listed items.
Although terms such as “first,” “second,” and “third” may be used herein to describe various members, components, regions, layers, or sections, these members, components, regions, layers, or sections are not to be limited by these terms. Rather, these terms are only used to distinguish one member, component, region, layer, or section from another member, component, region, layer, or section. Thus, a first member, component, region, layer, or section referred to in examples described herein may also be referred to as a second member, component, region, layer, or section without departing from the teachings of the examples.
The terminology used herein is for describing various examples only, and is not to be used to limit the disclosure. The articles “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises,” “includes,” and “has” specify the presence of stated features, numbers, operations, members, elements, and/or combinations thereof, but do not preclude the presence or addition of one or more other features, numbers, operations, members, elements, and/or combinations thereof. In addition, the use of the term “may” herein with respect to an example or embodiment, e.g., as to what an example or embodiment may include or implement, means that at least one example or embodiment exists where such a feature is included or implemented while all examples and embodiments are not limited thereto.
Due to manufacturing techniques and/or tolerances, variations of the shapes shown in the drawings may occur. Thus, the examples described herein are not limited to the specific shapes shown in the drawings, but include changes in shape that occur during manufacturing.
The features of the examples described herein may be combined in various ways as will be apparent after an understanding of the disclosure of this application. Further, although the examples described herein have a variety of configurations, other configurations are possible as will be apparent after an understanding of the disclosure of this application.
Hereinafter, exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings.
Referring to
The wireless power receiver 200 may provide the received power to an electronic device 300. The wireless power receiver 200 may be included as one component in the electronic device 300, or may be a separate component connected to the electronic device 300.
Referring to
In the selection phase, the wireless power transmitter 100 may transmit a beacon signal. In a case in which an impedance level of the beacon signal which is being transmitted is changed, the wireless power transmitter 100 may determine that an external object is positioned around the wireless power transmitter 100.
In a case in which it is determined that a predetermined external object is adjacent to the wireless power transmitter 100 in the selection phase, the wireless power transmitter 100 may enter the ping phase (S220).
The wireless power transmitter 100 may determine whether or not the external object adjacent to the wireless power transmitter 100 is the wireless power receiver by performing a quality factor (Q-factor) measurement in the ping phase. The wireless power transmitter 100 may discriminate a kind of the external object disposed to be adjacent thereto and whether or not a transmitting coil employed in the wireless power transmitter and the external object are aligned by performing the Q-factor measurement in the ping phase. In a case in which the external object adjacent to the wireless power transmitter 100 is determined to be the wireless power receiver as a result of the Q-factor measurement, the wireless power transmitter 100 may transmit a ping signal.
The wireless power transmitter 100 may enter an identification and configuration phase in response to a response signal of the wireless power receiver for the ping signal (S230).
In a case in which the external object is the wireless power receiver, the wireless power receiver may transmit the response signal for the received ping signal. The response signal of the wireless power receiver may include any one or any combination of any two or more of signal strength information, information on a kind of the wireless power receiver, and information on input voltage strength. Therefore, the wireless power transmitter 100 may identify a target and a power demand using the response signal of the wireless power receiver for the ping signal.
The identification and configuration phase may include a negotiation phase. In the negotiation phase, the wireless power transmitter 100 may transmit a negotiation request signal, and may obtain information on power required by the wireless power receiver as a response of the wireless power receiver for the negotiation request signal. As an example, the power required by the wireless power receiver may be one of low power such as 5[W] and medium power such as 15[W].
The wireless power transmitter 100 may enter the power transfer phase (S240).
The wireless power transmitter 100 may wirelessly provide the power to the wireless power receiver using the information identified in the identification and configuration phase.
In addition, in addition to the above-mentioned phases, a calibration phase of calibrating power loss caused by a foreign object which may be disposed between the wireless power transmitter 100 and the wireless power receiver may be performed by the wireless power transmitter 100. The wireless power transmitter 100 may receive packet information on a load to calibrate the power loss caused by the foreign object. As an example, the packet information on the load may be packet information on a light load and a connected load.
As described above, the wireless power transmitter 100 may determine whether or not the external object adjacent to the wireless power transmitter 100 is the wireless power receiver by performing the quality factor (Q-factor) measurement in the ping phase.
In order to perform the Q-factor measurement, a frequency sweep signal of which a frequency is changed in a predetermined range may be applied to the coil of the wireless power transmitter, and a maximum voltage gain obtained according to the frequency sweep signal and a frequency corresponding to the maximum voltage gain may be used. However, since the Q-factor measurement manner using the maximum voltage gain and the frequency corresponding to the minimum voltage gain needs to include a separate power source having a low voltage level in order to apply the frequency sweep signal of a voltage level which is low enough not to activate the wireless power receiver, there are a problem that a circuit configuration becomes complicated and product cost is increased.
The wireless power transmitter 100 according to an exemplary embodiment may limit a current applied to the inverter member of the wireless power transmitter 100 and may measure Q-factor from the frequency corresponding to a minimum output voltage of the inverter member, in a time section for performing the Q-factor measurement in the ping phase, without including the separate power source.
The wireless power transmitter 100 may include a current limiting part 110, an inverter member 120, a resonating member 130, and a controller 140. Input power Vin of the wireless power transmitter 100 may be direct current (DC) power. According to exemplary embodiments, the input power Vin may be alternating current (AC) power, and in this case, the wireless power transmitter 100 may further include an AC-DC converting circuit receiving the AC power and generating the DC power.
The current limiting part 110 disposed between the input power Vin and the inverter member 120 may limit a level of the current applied to the inverter member 120 by the input power Vin in the time section for the Q-factor measurement, and may provide a reference level of current to the inverter member.
The current limiting part 110 may include a resistance element R and a switch SW which are disposed to be in parallel to each other between the input power Vin and the inverter member 120. The switch SW may perform an off-operation in the time section for the Q-factor measurement to limit the level of the current applied to the inverter member 120 by the input power Vin, and perform an on-operation in another time section, particularly, the time section of the power transfer phase, to transfer a current generated by the input power Vin to the inverter member 120. That is, the switch SW may be open during the Q-factor measurement and closed during the power transfer phase.
In this case, the level of the current applied to the inverter member 120 in the time section for the Q-factor measurement may be lower than the level of the current applied to the inverter member 120 in the time section of the power transfer phase. Resistance of the resistance element R may be determined according to a voltage of the input power Vin in order to limit the level of the current applied to the inverter member 120.
The inverter member 120 may include a plurality of transistors Q1 and Q2. The plurality of transistors Q1 and Q2 of the inverter member 120 may alternately perform a switching operation to operate the resonating member 130. The inverter member 120 may be an inverter of a half-bridge type in which two transistors Q1 and Q2 are connected in series with each other as illustrated in
The resonating member 130 may include a capacitor Cr and a coil Lr which are connected in series with an output terminal of the inverter member 120. A resonance frequency of the resonating member 130 may be determined according to capacitance of the capacitor Cr and inductance of the coil Lr. The resonating member 130 may wirelessly generate power from the AC power transferred from the inverter member 120 in the power transfer phase and transmit the generated power to the outside.
The controller 140 may control a switching operation of the switch SW of the current limiting part 110 and the plurality of transistors Q1 and Q2 of the inverter member 120. The controller 140 may control the plurality of transistors Q1 and Q2 of the inverter member 120 so that the plurality of transistors Q1 and Q2 alternately perform the switching operation by the frequency manner, the variable frequency manner, the duty-rate modulation manner, the phase shift manner, and the like.
The controller 140 may control the switch SW of the current limiting part 110 so that the switch SW performs an off-operation in the time section for the Q-factor measurement to limit the level of the current applied to the inverter member 120 by the input power Vin, and control the switch SW of the current limiting part 110 so that the switch SW performs an on-operation in other time sections, particularly, a time section of the power transfer phase, to transfer a current generated by the input power Vin to the inverter member 120. The controller 140 may control the switch SW to open in response to a determination by the controller 140 to perform Q-factor measurement, and may control the switch SW to close in response to a determination by the controller 140 to terminate the Q-factor measurement and/or perform another operation such as power transfer.
The controller 140 may measure the quality factor according to the output voltage of the inverter member 120 detected in the time section for the Q-factor measurement and frequencies of the switching signals provided to the plurality of transistors Q1 and Q2 of the inverter member 120. According to an exemplary embodiment, the controller 140 may measure the Q-factor from the frequency of the switching signal corresponding to a point of time at which the minimum output voltage of the inverter member 120 is detected.
The controller 140 may determine the kind of the external object adjacent to the wireless power transmitter 100 and whether or not a center of the coil Lr and the external object are aligned with each other according to the quality factor, and determine whether or not the wireless power transmitter 100 enters the wireless power transfer phase.
Referring to
In addition, referring to
Comparing the frequency of the switching signal the inverter member of
In addition, comparing the frequency of the switching signal of the inverter member of
Referring to
In addition, referring to
Table 1 below is a table illustrating results of the simulation graphs of
In the Comparative Example, a quality factor may be measured by applying a frequency sweep signal of which a frequency is changed in a predetermined range to the coil of the wireless power transmitter, and using a maximum voltage gain obtained according to the frequency sweep signal and a frequency corresponding to the maximum voltage gain.
In the case of Case 2 in Table 1 above, the result in which the frequency of the Comparative Example exceeds 120 [KHz], which is the measured maximum frequency, is derived, where some differences from the Inventive Example in the present disclosure occur. However, referring to the frequencies of Cases 1, and 3 to 5, the Inventive Example in the present disclosure and the Comparative Example derive a similar result, where it may be identified that in the case of the Inventive Example, a precise quality factor may be measured with lowering product cost by removing a separate power source, unlike the Comparative Example.
In addition, referring to Table 1, the wireless power transmitter according to an exemplary embodiment may accurately discriminate or determine the kind of the external object adjacent thereto and whether or not the center of the coil and the external object are aligned with each other, according to the quality factor.
As set forth above, according to the exemplary embodiments in the present disclosure, the foreign object may be detected before the power transfer phase, whereby a safety of a user may be provided, and a deformation of a shape of the wireless power transmitter/receiver may be prevented.
The controller 140 in
The methods illustrated in
Instructions or software to control computing hardware, for example, one or more processors or computers, to implement the hardware components and perform the methods as described above may be written as computer programs, code segments, instructions or any combination thereof, for individually or collectively instructing or configuring the one or more processors or computers to operate as a machine or special-purpose computer to perform the operations that are performed by the hardware components and the methods as described above. In one example, the instructions or software include machine code that is directly executed by the one or more processors or computers, such as machine code produced by a compiler. In another example, the instructions or software includes higher-level code that is executed by the one or more processors or computer using an interpreter. The instructions or software may be written using any programming language based on the block diagrams and the flow charts illustrated in the drawings and the corresponding descriptions in the specification, which disclose algorithms for performing the operations that are performed by the hardware components and the methods as described above.
The instructions or software to control computing hardware, for example, one or more processors or computers, to implement the hardware components and perform the methods as described above, and any associated data, data files, and data structures, may be recorded, stored, or fixed in or on one or more non-transitory computer-readable storage media. Examples of a non-transitory computer-readable storage medium include read-only memory (ROM), random-access memory (RAM), flash memory, CD-ROMs, CD−Rs, CD+Rs, CD−RWs, CD+RWs, DVD-ROMs, DVD−Rs, DVD+Rs, DVD−RWs, DVD+RWs, DVD-RAMs, BD-ROMs, BD-Rs, BD-R LTHs, BD-REs, magnetic tapes, floppy disks, magneto-optical data storage devices, optical data storage devices, hard disks, solid-state disks, and any other device that is configured to store the instructions or software and any associated data, data files, and data structures in a non-transitory manner and provide the instructions or software and any associated data, data files, and data structures to one or more processors or computers so that the one or more processors or computers can execute the instructions. In one example, the instructions or software and any associated data, data files, and data structures are distributed over network-coupled computer systems so that the instructions and software and any associated data, data files, and data structures are stored, accessed, and executed in a distributed fashion by the one or more processors or computers.
While this disclosure includes specific examples, it will be apparent after an understanding of the disclosure of this application that various changes in form and details may be made in these examples without departing from the spirit and scope of the claims and their equivalents. The examples described herein are to be considered in a descriptive sense only, and not for purposes of limitation. Descriptions of features or aspects in each example are to be considered as being applicable to similar features or aspects in other examples. Suitable results may be achieved if the described techniques are performed in a different order, and/or if components in a described system, architecture, device, or circuit are combined in a different manner, and/or replaced or supplemented by other components or their equivalents. Therefore, the scope of the disclosure is defined not by the detailed description, but by the claims and their equivalents, and all variations within the scope of the claims and their equivalents are to be construed as being included in the disclosure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2017-0008805 | Jan 2017 | KR | national |
