ENERGY CONTRACT GUIDELINES FOR WIRELESS CHARGING

Abstract

A wireless power transmitter can include an inverter that receives input power and generates an AC output voltage, a coil of the wireless power transmitter coupled to its AC output and magnetically coupled to a corresponding coil of a wireless power receiver, and a control and communication module. The control and communication module can receive identification information from the wireless power receiver, receive voltage information from the wireless power receiver, calculate a coupling factor with the wireless power receiver (at least partially based on the received identification and voltage information), calculate a power transfer level based on the calculated coupling factor, and negotiate a power contract with the wireless power receiver (at least partially based on the calculated power transfer level).

Description

CROSS-REFERENCE TO RELATED REGISTRATIONS

[0001] This application claims priority over the preliminary US patent application No. 63 / 364,463, filed on May 10, 2022, entitled “POWER CONTRACT POLICY FOR WIRELESS CHARGING”, and the disclosure of which is incorporated by reference in its entirety for all purposes. BACKGROUND

[0002] Wireless power transfer (WPT), like inductive power transfer (IPT), can be used to provide energy for charging various battery-powered electronic devices. One application where WPT is becoming increasingly common is in the consumer electronics industry, with devices such as mobile phones (i.e., smartphones) and their accessories (e.g., wireless headphones, smartwatches, etc.), as well as tablets and other types of portable computers and their accessories (e.g., styluses, etc.). SUMMARY

[0003] A wireless power transmitter can include an inverter that receives input power and generates an AC output voltage, a coil of the wireless power transmitter coupled to its AC output and magnetically coupled to a corresponding coil of a wireless power receiver, and a control and communication module. The control and communication module can receive identification information from the wireless power receiver, receive voltage information from the wireless power receiver, calculate a coupling factor with the wireless power receiver (at least partially based on the received identification and voltage information), calculate a power transfer level based on the calculated coupling factor, and negotiate a power contract with the wireless power receiver (at least partially based on the calculated power transfer level).

[0004] The identification information can specifically identify the wireless energy receiver. The identification information can identify the wireless energy receiver as a member of a class of wireless energy receivers.

[0005] The coupling factor can be calculated according to the following equation: k=C0⋅VertectVinv+VCTXpp+C1 where k is the coupling factor, Vrect is a rectifier voltage that makes up at least part of the received voltage information, Vinv is the input DC voltage of the inverter, VCTXpp is a peak voltage across a transmitter tuning capacitor, and C0 and C1 are matching coefficients.

[0006] The energy transfer level can be calculated according to the following equation: Ptarget=k2⋅Cpwr where Ptarget is the energy that can be delivered to the receiver, k is the coupling factor, and Cpwr is a constant for a transmitter / receiver combination that is determined by the controller at least partially based on the received receiver identification information. Cpwr may be stored in a memory of the controller and retrieved at least partially based on the received receiver identification information. Cpwr may be contained within the received receiver identification information. Cpwr can be calculated using the following formula: Cpwr=Prect_max+RXLosskmin2 where Prect_max is the maximum total energy level required by the receiver, RXLoss is the energy lost in the receiver, and kmin is the minimum coupling coefficient corresponding to a maximum permissible displacement between transmitter and receiver.

[0007] A procedure carried out by a wireless energy transmitter to negotiate a wireless energy supply contract with a wireless energy receiver may include receiving identification information from the wireless energy receiver via a wireless communication link, receiving voltage information from the wireless energy receiver via the wireless communication link, calculating, with a processor of the wireless energy transmitter, a coupling factor with the wireless energy receiver at least partially based on the received identification information and voltage information, calculating, with the processor, an energy transfer level based at least partially on the calculated coupling factor, and negotiating the wireless energy supply contract based at least partially on the calculated energy transfer level.

[0008] The identification information can specifically identify the wireless energy receiver. The identification information identifies the wireless energy receiver as a member of a class of wireless energy receivers.

[0009] The coupling factor can be calculated according to the following equation: k=C0⋅VrecrVinv+VCTXpp+C1 where k is the coupling factor, Vrect is a rectifier voltage which is the received voltage information, Vinv is the input DC voltage of the inverter, VCTXpp is a peak voltage across a transmitter tuning capacitor, and C0 and C1 are matching coefficients.

[0010] The energy transfer level can be calculated according to the following equation: Ptarget=k2⋅Cpwr where Ptarget is the energy that can be delivered to the receiver, k is the coupling factor, and Cpwr is a constant for a transmitter / receiver combination stored in a controller memory and selected based on the received receiver identification information. Cpwr may be stored in a controller memory and retrieved at least partially based on the received receiver identification information. Cpwr may be contained within the received receiver identification information. Cpwr can be calculated using the following formula: Cpwr=Prect_max+RXLosskmin2 where Prect_max is the maximum total energy level required by the receiver, RXLoss is the energy lost in the receiver, and kmin is the minimum coupling coefficient corresponding to a maximum permissible displacement between transmitter and receiver.

[0011] A wireless energy transmission device may include a wireless energy coil magnetically coupled to a corresponding coil of another wireless energy transmission device, and a control and communication module that receives identification information from the other wireless energy transmission device, calculates a coupling factor with the wireless energy transmission device at least partially based on the received identification information and voltage information, calculates an energy transmission level based on the calculated coupling factor, and negotiates an energy contract with the other wireless energy transmission device at least partially based on the calculated energy transmission level.

[0012] The identification information can specifically identify the other wireless power transmission device. The identification information can identify the other wireless power transmission device as a member of a class of wireless power transmission devices.

[0013] The coupling factor is calculated according to the following equation: k=C0⋅VrecrVinv+VCTXpp+C1 where k is the coupling factor, Vrect is a rectifier voltage of a wireless power receiver, Vinv is a DC input voltage of a wireless power transmitter inverter, VCTXpp is a peak voltage across a transmitter tuning capacitor, and C0 and C1 are matching coefficients. One wireless power transmission device can be the wireless power receiver, and the other wireless power transmission device can be the wireless power transmitter. Vinv and VCTXpp represent at least some of the received voltage information. The power transmission level is calculated according to the following equation: Ptarget=k2⋅Cpwr where Ptarget is the energy that can be delivered to the receiver for wireless energy, k is the coupling factor, and Cpwr is a constant for a transmitter / receiver combination stored in a memory of the controller and communication module, and selected based on the received identification information. Cpwr may be stored in a memory of the controller and is retrieved at least partially based on the received identification information. Cpwr may be contained within the identification information. Cpwr can be calculated using the following formula: Cpwr=Prect_max+RXLosskmin2 where Prect_max is the maximum total energy level required by the receiver, RXLoss is the energy lost in the receiver, and kmin is the minimum coupling coefficient corresponding to a maximum permissible displacement between transmitter and receiver.

[0014] The energy transfer level can be calculated according to the following equation: Ptarget=k2⋅Cpwr where Ptarget is the energy that can be delivered to the receiver for wireless energy, k is the coupling factor, and Cpwr is a constant for a transmitter / receiver combination stored in a memory of the controller and communication module, and selected based on the received identification information. Cpwr may be stored in a memory of the controller and is retrieved at least partially based on the received identification information. Cpwr may be contained within the identification information. Cpwr can be calculated using the following formula: Cpwr=Prect_max+RXLosskmin2 where Prect_max is the maximum total energy level required by the receiver, RXLoss is the energy lost in the receiver, and kmin is the minimum coupling coefficient corresponding to a maximum permissible displacement between transmitter and receiver. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 illustrates a block diagram of a wireless power transmission system. Fig. Figures 2A to 2C illustrate different configurations of a wireless power transmission system. Fig. Figure 3 illustrates tables with energy transfer levels for a wireless energy transfer system. Fig. Figure 4 illustrates a simplified diagram of a wireless power transmission system. Fig. Figure 5 illustrates a process for determining a target energy transfer level in a wireless energy transfer system. Fig. Figure 6 illustrates tables with energy transfer levels for a wireless energy transfer system. Fig. Figure 7 illustrates a process for calculating a wireless energy transfer level in a wireless energy transfer system. DETAILED DESCRIPTION

[0015] For explanatory purposes, numerous specific details are presented in the following description to provide a comprehensive understanding of the disclosed concepts. For the sake of simplicity, some drawings in this disclosure depict structures and devices in block diagram form. For clarity, not all features of an actual implementation are described in this disclosure. Furthermore, the language used in this disclosure has been chosen for readability and instructional purposes. Various embodiments of the disclosed concepts are illustrated in the accompanying drawings, where identical references denote identical elements, in an exemplary and non-exhaustive manner. For the sake of simplicity and clarity of illustration, reference symbols have been repeated in the various figures, where appropriate, to indicate corresponding or analogous elements.Furthermore, numerous specific details are set forth to provide a comprehensive understanding of the implementations described herein. In other cases, methods, procedures, and components have not been described in detail so as not to obscure the relevant function being described. References to "a," "a particular," or "another" embodiment in this disclosure do not necessarily refer to the same or a different embodiment, and they mean at least one. A given figure may be used to illustrate the features of more than one embodiment or more than one kind of disclosure, and not all elements in the figure may be required for a given embodiment or kind.A reference symbol, when provided in one drawing, refers to the same element in each of the different drawings, although it may not be repeated in every drawing. Unless otherwise indicated, the drawings are not to scale, and the proportions of certain parts may be exaggerated to better illustrate details and features of the present disclosure.

[0016] Fig. Figure 1 illustrates a simplified block diagram of System 100 for wireless power transmission. The wireless power transmission system includes a power transmitter (PTx) 110, which wirelessly transmits power to a power receiver (PRx) 120 via inductive coupling 130. The power transmitter 110 can receive input power, which is converted by an inverter 114 into an alternating voltage with specific voltage and frequency characteristics. The inverter 114 can be controlled by a control unit / communication module 116, which operates as described below. In various embodiments, the inverter control unit and the communication module can be implemented in a common system, such as a microprocessor-based system, a microcontroller, or the like.

[0017] In other embodiments, the inverter control unit can be implemented by a separate control unit module and communication module, which provide communication between them. The inverter 114 can be constructed using any suitable circuit topology (e.g., full bridge, half bridge, etc.) and implemented using any suitable semiconductor switching device technology (e.g., MOSFETs, IGBTs, etc.) fabricated using silicon, silicon carbide, or gallium nitride devices.

[0018] The inverter 114 can supply the generated alternating voltage to a transmitter coil 112. In addition to a wireless coil, which enables magnetic coupling with the receiver, the inverter can also be used in the following configuration: Fig. Figure 1 illustrates transmitter coil block 112, which may include a tuning circuit arrangement such as additional chokes and capacitors to facilitate operation of the transmitter under varying conditions, such as different degrees of magnetic coupling to the receiver, different operating frequencies, etc. The wireless coil itself can be constructed in a variety of different ways. In some embodiments, the wireless coil may be formed as a winding of wire around a suitable coil. In other embodiments, the wireless coil may be formed as conductive traces on a printed circuit board. Other arrangements are also possible and may be used in conjunction with the various embodiments described herein. The wireless transmitter coil may also have a core of magnetically permeable material (e.g.,Include a ferrite core configured to influence the coil's flux pattern in a manner suitable for the specific application. The teachings contained herein can be applied in conjunction with a variety of transmitter coil arrangements suitable for a given application.

[0019] The PTx control / communication module 116 can monitor the transmitting coil and use the derived information to control the inverter 114 according to a given situation. For example, the control / communication module can be configured to operate the inverter 114 at a given frequency or output voltage, depending on the specific application. In some embodiments, the control / communication module can be configured to receive information from the PRx device and control the inverter 114 accordingly. This information can be received via the power transmission coils (i.e., in-band communication) or via a separate communication channel (not shown, i.e., out-of-band communication).For in-band communication, the control / communication module 116 can capture and decode signals (such as voltage, frequency, or load fluctuations) imposed on the magnetic link by the PRx to receive information and can instruct the inverter to modulate the supplied power by manipulating various parameters of the generated voltage (such as voltage, frequency, phase, etc.) to send information to the PRx. In some embodiments, the control / communication module can be configured to use frequency-shift keying (FSK) communication, where the frequency of the inverter signal is modulated to transmit data to the PRx. The control / communication module 116 can also be configured to capture amplitude-shift keying (ASK) or load-modulation-based communication from the PRx.In both cases, the control / communication module 126 can be configured to vary the current drawn at the receiver side to manipulate the waveform viewed on the Tx coil, thereby transmitting information from the PRx to the PTx. For out-of-band communication, additional modules can be provided to enable communication between the PTx and PRx, such as WiFi, Bluetooth, other radio links, or another suitable communication channel. As mentioned above, the control / communication module 116 can be a single module, for example, implemented on a single integrated circuit, or it can be composed of multiple modules / devices implemented on different integrated circuits or a combination of integrated and discrete circuits containing both analog and digital components.The lessons contained herein are not limited to any particular arrangement of the control unit / communication circuit arrangement.

[0020] The PTx device 110 can optionally include further systems and components, such as a separate communication module (“comm. module”) 118. In some embodiments, the communication module 118 can communicate with a corresponding module tag in the PRx via the power transmission coils. In other embodiments, the communication module 118 can communicate with a corresponding module using a separate physical channel 138.

[0021] As mentioned above, the wireless power transmission system also includes a wireless power receiver (PRx) 120. The wireless power receiver can include a receiver coil 122, which can be magnetically coupled to the transmitter coil 112 130. As with the transmitter coil 112 discussed above, the Fig. Figure 1 illustrates a receiver coil block 122 that includes a tuning circuit arrangement, such as additional inductors and capacitors, to facilitate the transmitter's operation under varying conditions, such as different degrees of magnetic coupling to the receiver, different operating frequencies, etc. The wireless coil itself can be constructed in a variety of different ways. In some embodiments, the wireless coil can be formed as a winding of wire around a suitable coil. In other embodiments, the wireless coil can be formed as conductive traces on a printed circuit board. Other arrangements are also possible and can be used in conjunction with the various embodiments described herein. The wireless receiver coil can also have a core of magnetically permeable material (e.g.,Include a ferrite core configured to influence the coil's flux pattern in a manner suitable for the specific application. The teachings contained herein can be applied in conjunction with a variety of receiver coil arrangements suitable for a given application.

[0022] The receiver coil 122 outputs an induced alternating voltage via magnetic induction through the transmitter coil 112. This output alternating voltage can be supplied to a rectifier 124, which provides a direct current output power for one or more loads associated with the PRx device. The rectifier 124 can be controlled by a control unit / communication module 126, which operates as further described below. In various embodiments, the rectifier control unit module and the communication module can be implemented in a common system, such as a system based on a microprocessor, a microcontroller, or the like. In other embodiments, the rectifier control unit can be implemented by separate control unit modules and communication modules, which provide communication between them.The rectifier 124 can be constructed using any suitable circuit topology (e.g. full bridge, half bridge, etc.) and implemented using any suitable semiconductor switching device technology (e.g. MOSFETs, IGBTs, etc.) manufactured using silicon, silicon carbide, or gallium nitride devices.

[0023] The PRx control / communication module 126 can monitor the receiver coil and use the information derived from this monitoring to control the rectifier 124 according to a given situation. For example, the control / communication module can be configured to cause the rectifier 124 to provide a given output voltage depending on the specific application. In some embodiments, the control / communication module can be configured to send information to the PTx device to effectively control the power supplied to the receiver. This information can be received by being transmitted over the power transmission coils (i.e., in-band communication) or can be sent over a separate communication channel (not shown, i.e., out-of-band communication).For in-band communication, the control / communication module 126 can, for example, modulate load current or other electrical parameters of the received energy to send information to the PTx. In some embodiments, the control / communication module 126 can be configured to capture and decode signals imposed on the magnetic link (such as voltage, frequency, or load fluctuations) by the PTx in order to receive information from the PTx. In some embodiments, the control / communication module 126 can be configured to receive frequency-shift keying (FSK) communication, in which the frequency of the inverter signal has been modulated to transmit data to the PRx. The control / communication module 126 can be configured to generate amplitude-shift keying (ASK) or load-modulation-based communication from the PRx.In both cases, the control unit / communication module 126 can be configured to vary the current drawn at the receiver side to manipulate the waveform viewed on the Tx coil, thereby transmitting information from the PRx to the PTx. For out-of-band communication, additional modules can be provided to enable communication between the PTx and PRx, for example, WiFi, Bluetooth, other radio links, or another suitable communication channel.

[0024] As mentioned above, the control / communication module 126 can be a single module, for example, provided on a single integrated circuit, or it can be composed of several modules / devices provided on different integrated circuits or a combination of integrated and discrete circuits, incorporating both analog and digital components. The teachings herein are not limited to any particular arrangement of the control / communication circuitry.

[0025] The PRx device 120 can optionally include further systems and components, such as a communication module 128. In some embodiments, the communication module 128 can communicate with a corresponding module in the PTx via the energy transfer coils. In other embodiments, the communication module 128 can communicate with a corresponding module or tag using a separate physical channel 138.

[0026] Numerous variations and improvements to the wireless power transmission system described above are possible, and the following teachings are applicable to any of these variations and improvements.

[0027] The wireless power transfer described above depends on the degree of electromagnetic coupling between PTx and PRx. For example, in inductive charging systems, the transmitter coil 112 and the receiver coil 122 can be conceived as a loosely coupled transformer. Therefore, the relative position of PTx and PRx can influence the degree of magnetic coupling between them, which in turn can affect the power transfer capability of the system. Fig. Figure 2A illustrates a simplified diagram of a PTx (110)-PRx (120) system. Both devices are shown in a top view (upper part of the diagram) and a sectional view from the edge (lower part of the figure). The PTx device 110 includes a transmitter coil 112, and the PRx device 120 includes a receiver coil 122. In some embodiments, the PTx device 110 may be a wireless charging pad, mat, or stand (or other wireless power transmission device), and the PRx device 120 may be a mobile phone, tablet computer, smartwatch (or other wireless power receiving device). Although the respective devices are generally shown as rectangular with generally circular charging coils, it should be noted that other configurations are possible.

[0028] Fig. Figure 2B illustrates PTx 110 and PRx 120 in an "optimal" orientation. Fig. 2B, the devices are horizontally aligned (as shown in the top view) and vertically aligned, and as close together as possible (as illustrated in the sectional view). In this context, the terms "horizontal" and "vertical" are used only for simplicity, and the actual orientation of the system may vary. The following description is applicable to a system with any orientation, although "horizontal" and "vertical" are still used for clarity of context. Fig. Figure 2C illustrates the devices with a slight misalignment. In particular, there is a radial displacement "r" that can be seen by noting that the centers of coils 112 and 122 no longer coincide in the top view. Such a radial displacement can have many causes, for example, if a user slightly misaligns their phone on a charging pad. Furthermore, there is also a vertical displacement "z" that can be seen by noting the separation between PTx device 110 and PRx device 120 in the sectional view. This vertical displacement can also have many causes, for example, a phone in a case or cover. The sectional view also illustrates the lateral / radial displacement. It should be noted that in some situations, only a radial or only a vertical displacement may be present.

[0029] In any case, the offsets described above can reduce the degree of magnetic coupling between the PTx and PRx devices. This reduced magnetic coupling can limit the amount of energy that can be delivered from PTx 110 to PRx 120 while adhering to the power limitations of PTx 110. In particular, reduced coupling between PTx 110 and PRx 120 decreases the proportion of energy transferred by PTx 110 that is received by PRx 120. PTx 110 has a maximum operating voltage and a maximum current that can be supplied, effectively resulting in a maximum energy transfer level. Additionally, in some applications, the PTx controller 116 may become unstable when attempting to provide an energy level requested by the PRx controller 126 that is not possible / feasible at a given degree of coupling.If the coupling between PTx 110 and PRx 120 decreases, PTx may no longer be able to supply the energy requested by PRx 120. In some of these cases, it may be desirable for PTx 110 and PRx 120 to negotiate an energy contract that specifies the level of energy PTx can supply and PRx can expect to receive.

[0030] Such an energy contract can be based, at least in part, on an estimate of the maximum available power transfer from PTx 110 to PRx 120, based on the system limitations imposed by the degree of coupling between them. One way to achieve such an estimate is based on measurements of the voltage gain from PTx 110 to PRx 120. More precisely, PTx 110 and PRx 120 can be operated under various predetermined fixed charging conditions, and PTx can calculate the gain for this charging condition by measuring the inverter output voltage Vinv ( Fig. 4) (i.e., the input voltage of inverter 114) by the rectifier output voltage Vrect ( Fig. 4) (i.e., the rectified voltage after the rectifier) ​​divided. In some cases, the specific charging conditions may be determined by an industry standard specification or by negotiation / agreement between the devices. In any case, a negotiated energy contract may include an energy target or limit that depends on these estimated voltage gains.

[0031] Fig. Figure 3 illustrates Table 301, which plots the estimated energy transfer levels for varying values ​​of the radial offset (r) and the vertical offset (z) for an exemplary embodiment. It is understood that these values ​​are merely examples and that different values ​​may be calculated for different systems with varying physical, electrical, and magnetic properties. The estimated energy transfer levels can be expressed in watts, and the radial offsets can be distances in millimeters. Values ​​greater than or equal to a high energy transfer level (e.g., 15 W) are indicated by an "H". Values ​​less than or equal to a low energy transfer level (e.g., 5 W) are indicated by an "L". Values ​​between these two thresholds are indicated by an "I" (for "intermediate").In some cases, the estimated energy can be negative (a nonsensical result), in which case "-ve" is indicated. Thus, with a radial / vertical offset of 0.0, the estimated energy transfer capability might be high (e.g., 28 W, which is greater than the energy transfer level of 15 W), and drop to -30 W with a radial offset of 8 mm (a nonsensical negative value, represented as "-ve"), and to -15 W with a vertical offset of 6 mm (another nonsensical negative value, represented as "-ve"). It should be noted that the negative values ​​result from an energy estimation technique based on the product of the voltage gains determined under different charge conditions. In particular, if any of the measured voltage gains is negative, this will result in a negative energy output level, which is quite nonsensical.

[0032] To address these and other inaccuracies of the stress amplification-based estimation method, Table 302 in Fig. Three target energy levels can be set based on the estimated energy calculation from Table 301. Generally, for values ​​greater than or equal to a high energy transfer level (e.g., 15 W), the energy target can be set to the high energy transfer level (denoted "H"), which may correspond to a nominal energy level of PTx 110. For estimated energy transfer capabilities below the low energy transfer level (e.g., 5 W), the energy target can be set to the low energy transfer level (denoted "L"), which may be a minimum energy transfer target specified by an industry standard. This energy transfer target value may also be sufficiently below the maximum capability of the PTx 110 to avoid control instability or other operational problems.For interim energy transmission estimates, the energy contract can be set to one or more predefined intermediate levels (labeled "I"). Each of the provided values ​​is merely an example, and any suitable energy levels can be used depending on the specific implementation.

[0033] As briefly mentioned above, energy estimation techniques based on measured voltage gains under different charge conditions can suffer from accuracy problems. Additionally, performing tests under varying charge conditions can be time-consuming, undesirably increasing the startup time between placing a PRx device on the PTx and the start of full-power wireless transmission. Furthermore, gain measurements can be subject to numerous inaccuracies due to noise, etc. Therefore, it may be preferable to provide energy estimates based on a direct measurement of the coupling factor "k" ( Fig. 4).

[0034] Fig. Figure 4 illustrates a partially simplified electrical schematic of a wireless power transmission system with a PTx 110, represented by the inverter input voltage Vinv applied to the inverter bridge (e.g., full bridge, half bridge, etc.). The PRx 120 includes the transmitting coil 112 / inductor LTx, the receiving coil 122 / inductor LRx, the tuning capacitor CRx / 423, the rectifier 124, and the output load 429, represented by resistor Prect. Fig. Figure 4 also includes the resistances RLRx / 422a, RCRx / 423a, and RPAR / 424a, which are not actual discrete resistances but correspond to the inherent resistances of the receiving coil 122, the tuning capacitor 423, and other parasitic losses of the system. The received energy PRx / 442 can be thought of as including two components: Prect / 443, which is the energy delivered to the load Rrect / 429, and the energy losses RXLoss / 441, which are attributed to the parasitic resistances.

[0035] The energy transmission capability of such a system for wireless energy transmission can be expressed as follows: PRx_target=k2⋅Cpwr where k is the coupling factor between transmitter and receiver, and Cpwr is a property of the receiver that can be determined as described below. For a given coupling degree, a higher Cpwr value may result in a target energy calculation that is higher than the receiver requirement. Likewise, a lower Cpwr may result in a target energy calculation that is lower than the receiver requirement. To ensure adequate energy output, Cpwr can be determined using a "worst-case scenario," i.e., a relative position between PTx 110 and PRx 120 that exhibits the lowest acceptable coupling, i.e., a minimum coupling that still guarantees a specified energy transfer level. Thus: Cpwr=Prect_max+RXLosskmin2 where Cpwr is the required energy coefficient that guarantees maximum energy is targeted during energy negotiation, Prect_max is the maximum total energy level required by the receiver, RXLoss is the energy loss in the receiver (discussed above), and kmin is the minimum coupling coefficient, which generally corresponds to a maximum acceptable offset between PTx 110 and PRx 120. As mentioned above, this Cpwr factor in the PRx_target calculation above is a property of each receiver, which can have different electrical and magnetic characteristics. Since the transmitter can use this value to calculate the target energy level, the transmitter can access Cpwr for a receiver. In some cases, the transmitter can be programmed, either initially or via an update, with Cpwr values ​​for a range of compatible receivers.In other cases, the receiver can provide its Cpwr value to the sender as part of an initialization phase.

[0036] In some applications, Cpwr can be constant for a given transmitter / receiver device combination. Furthermore, its three constituent elements (Prect_max, RXLoss, and kmin) can also be constant for a given receiver or transmitter device. In other words, Cpwr and its constituent factors can be determined based on the physical, electrical, and magnetic properties of the device's design. To facilitate energy contract negotiation, PTx 110 can therefore store or otherwise access one or more Cpwr values ​​corresponding to one or more receivers or receiver types / classes. In each case, as part of the initialization / energy contract negotiation, PTx 110 can identify PRx 120 with which it communicates and use a suitable stored Cpwr value (or its constituent factors) for energy estimation, as described herein.Additionally or alternatively, PRx 120 could have its own (P. rect_max + R XLoss )-value and one or more kmin values ​​corresponding to one or more transmitters or transmitter types. Then, as part of the initialization / energy contract negotiation process, PTx 110 could store its own (P rect_max + R XLoss Provide a ) value or a suitable Cpwr value. Together or individually, this information can be considered identification information of the recipient, as it can provide the sender with appropriate characteristics of the recipient to enable the creation of a suitable energy contract.

[0037] Fig. Figure 5 illustrates a complete exemplary process 501 for calculating an energy contract target energy value for a system 502 using the principles described above. Only certain portions of this procedure may be performed during the PTx / PRx initialization / negotiation process, as some portions may only be performed once as part of the design / calibration / configuration of the respective receiver and / or transmitter devices. Table 503 presents a table of energy levels as described above with reference to Fig. 3. In Block 504, the intended specified range for maximum energy output can be determined. As an example, it may be desirable to guarantee maximum energy output within a radial offset of 2 mm and / or a vertical offset of 2 mm from perfect alignment. Then, in Block 505, a minimum coupling factor kmin that allows this energy transfer level can be determined. Furthermore, in Block 506, the worst rectifier losses can be determined. In Block 507, the minimum coupling factor and the worst-case losses can be used to calculate a Cpwr value using the formula described above. This Cpwr value (an example of receiver identification information) can be provided to the transmitter by programming (including initial configuration or software / firmware update), communication, or another suitable technique, as described above.Finally, the transmitter in Block 508 can calculate the target energy for different locations, i.e., different radial and / or vertical offsets, by using the Prect_target formula discussed above.

[0038] Fig. Figure 6 illustrates a first Table 601 with estimated energy values ​​using the calculation technique described above. As in Table 301 of Fig. 3. The estimated energy transfer levels for varying values ​​of the radial offset (r) and the vertical offset (z) are given for an exemplary embodiment. It is understood that these values ​​are merely exemplary and that different values ​​may be calculated for different systems with varying physical, electrical, and magnetic properties. The estimated energy transfer levels can be expressed in watts, and the radial offsets can be distances in millimeters.Thus, the estimated energy transfer capability can be 25 W for a radial / vertical offset of 0.0 (denoted "H" because this is above an exemplary high energy level of 15 W), drop to 8 W for a radial offset of 8 mm (denoted "I" because this is below the exemplary high energy level of 15 W but above an exemplary low energy level of 5 W), and drop to 6 W for a vertical offset of 6 mm (denoted "I" because this is below the exemplary high energy level of 15 W but above an exemplary low energy level of 5 W). It should be noted that these values ​​may be both more accurate and more conservative than those calculated using the above reference. Fig. 3 described alternative voltage gain-based calculation.

[0039] Fig. Figure 6 also illustrates a second Table 602 with target energy levels of the energy contract, which can optionally be set based on the estimated energy calculation from Table 601. Generally, for values ​​greater than a high energy level (e.g., 15 W), the energy target can be set to 15 W (denoted "H"), which may correspond to a nominal energy level of PTx 110. For estimated energy transfer capabilities below a low energy level (e.g., 5 W), the energy target can be set to 5 W (denoted "L"), which may be a minimum energy transfer target defined by an industry standard. This energy transfer target value may also be sufficiently below the maximum capability of the PTx 110 to avoid control instability or other operational problems.For interim estimates of energy transmission, the energy contract can be set to one or more predefined intermediate levels (designated “I”), as illustrated in Table 602 and discussed generally above.

[0040] The above energy estimation technique requires knowledge of the coupling factor "k" between PTx 110 and PRx 120. This factor can be obtained using various techniques. In one embodiment, it can be calculated according to the following formula: kest=C0⋅VertectVinv+VCTXpp+C1 where kest is the calculated (estimated) coupling factor, Vrect is the rectifier voltage measured during startup ( Fig. 4) where Vinv is the DC voltage at the inverter input on the transmitter side, VCTXpp is the peak voltage across the transmitter tuning capacitor in series with the power transfer winding (not shown), and C0 and C1 are matching coefficients empirically determined for a specific range of coupling factors. Since this relies on voltage measurements or values ​​obtained in only a single operating condition, the process can be performed faster than the voltage gain measurements described above under a multiple-charge condition.

[0041] Fig.Figure 7 illustrates a flowchart 700 of an energy contract negotiation process that can be performed by either a PTx 110 and / or a PRx 120. More precisely, the computation can be performed by a processor that is part of the controller 116 or 126, using data stored in appropriate memory, hard-coded in the respective device, or received from a counterpart device. Starting at block 751, a device (either PTx or PRx) can receive identification information from a counterpart device (either PRx or PTx). This identification information can be a simple identifier of the device or the device class to which the counterpart belongs, allowing the receiving device to look up a stored Cpwr value or a constituent factor for the counterpart device.For example, a sender (PTx) can receive identification information from a receiver (PRx) that allows the sender to determine a Cpwr value or a (P. rect_max + R XLoss )-value corresponding to the receiver device. Alternatively, a receiver (PRx) can receive identification information from a transmitter (PTx) that allows the receiver to look up a Cpwr value or a kmin value corresponding to the transmitter device. In another alternative, the counterpart device could provide its constituent factor (P) rect_max + R XLoss (for PRx or kmin for Ptx) directly. In any case, the receiving device can determine a suitable Cpwr value from the identification information.

[0042] In Block 752, a device (PTx or PRx) can receive voltage information from the counterpart device. This voltage information can be the rectifier voltage Vrect if the counterpart device is a PRx device, or the inverter voltage and the peak-to-peak voltage of the transmitter tuning capacitor if the counterpart device is a PTx device. In either case, the voltage information can be combined with a local voltage measurement to calculate (or estimate) the coupling factor "k" between the devices (Block 753). (In both cases, the device performing this calculation can also have all the matching coefficients required for the calculation stored.) From this k-value and the previously determined Cpwr value, an energy target for a negotiated energy contract can be calculated as described above (Block 754).

[0043] The foregoing describes exemplary embodiments of wireless power transfer systems that employ coupling-based power transfer estimation and negotiation of power supply contracts. Such systems can be used in a variety of applications, but are particularly advantageous when used in conjunction with wireless power transfer systems for personal electronic devices such as mobile computing devices (e.g., laptops, tablet computers, smartphones, and the like) and their accessories (e.g., wireless earbuds, styluses, and other input devices, etc.), as well as wireless charging accessories (e.g., charging mats, pads, stands, etc.).It is understood that, although numerous specific features and various embodiments have been described, unless otherwise stated in a mutually exclusive manner, the various features and embodiments can be combined in different implementations in a particular case. Therefore, the various embodiments described above are provided only for illustrative purposes and should not be understood as limiting the scope of protection of the disclosure. Various modifications and changes may be made to the principles and embodiments contained herein without deviating from the scope of protection of the disclosure and without deviating from the scope of protection of the claims.

[0044] The foregoing describes exemplary embodiments of wireless power transmission systems capable of transmitting certain information between the PTx and PRx in the system. This disclosure provides that this forwarding of information enhances the ability of the devices to efficiently provide each other with wireless power signals to support battery charging, such as by sharing the power processing capabilities of the devices. Entities implementing this technology should ensure that, to the extent that sensitive information is used in specific implementations, established data protection guidelines and / or practices are followed.In particular, such entities are expected to implement and consistently apply data protection practices that are generally recognized as meeting or exceeding industry or governmental requirements for protecting user privacy. Implementers should inform users where identifiable personal information is transmitted in a wireless power transfer system and allow users to consent to or decline participation. For example, such information may be presented to the user when they place a device on a power transmitter if the power transmitter is configured to query sensitive information from the power receiver.

[0045] The risk can be minimized by limiting data collection and deleting data as soon as it is no longer needed. Additionally, and where applicable, data de-identification can be used to protect a user's privacy. For example, a device identifier can be partially masked to transmit the device's energy characteristics without uniquely identifying the device. De-identification can be facilitated, where appropriate, by removing identifiers, controlling the amount or specificity of the stored data (e.g., collecting location data at the city level rather than the address level), controlling how data is stored (e.g., aggregating data across users), and / or through other methods such as differential data protection.Robust encryption can also be used to reduce the likelihood of communication between inductively coupled devices being corrupted. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] US 63 / 364,463

[0001]

Claims

[1] Wireless energy transmitter, comprising: an inverter that receives input power and generates an AC output voltage; a wireless energy transmitter coil coupled to the AC output and magnetically coupled to a corresponding coil of a wireless energy receiver; and a control and a communication module that: Receives identification information from the wireless energy transmitter; Receives voltage information from the wireless energy transmitter; calculates a coupling factor with the wireless energy transmitter based at least in part on the received identification information and the received voltage information; calculates an energy transfer level based on the calculated coupling factor; and negotiates an energy contract with the wireless energy receiver based at least in part on the calculated energy transmission level. [2] The wireless energy transmitter of claim 1, wherein the identification information specifically identifies the wireless energy receiver. [3] The wireless energy transmitter of claim 1, wherein the identification information identifies the wireless energy receiver as a member of a class of wireless energy receivers. [4] A wireless energy transmitter according to claim 1, wherein the coupling factor is calculated according to the following equation: k=C0⋅VrectVinv+VCTXpp+C1 where k is the coupling factor, Vrect is a rectifier voltage that constitutes at least part of the received voltage information, Vinv is the DC input voltage of the inverter, VCTXpp is a peak voltage across a transmitter tuning capacitor, and C0 and C1 are matching coefficients. [5] A wireless energy transmitter according to claim 1, wherein the energy transmission level is calculated according to the following equation: Ptarget=k2⋅Cpwr where Ptarget is the energy deliverable to the receiver, k is the coupling factor, and Cpwr is a constant for a transmitter / receiver combination determined by the controller based at least in part on the received receiver identification information. [6] The wireless energy transmitter of claim 5, wherein Cpwr is stored in a memory of the controller and retrieved based at least in part on the received receiver identification information. [7] A wireless power transmitter according to claim 5, wherein Cpwr is included in the received receiver identification information. [8] A wireless energy transmitter according to claim 5, wherein Cpwr is calculated according to the following formula: Cpwr=Prect_max+RXLosskmin2 where Prect_max is the maximum total energy level required by the receiver, RXLoss is the energy lost in the receiver, and kmin is the minimum coupling coefficient corresponding to a maximum allowable shift between transmitter and receiver. [9] A method performed by a wireless energy transmitter for negotiating a wireless energy supply contract with a wireless energy receiver, the method comprising: Receiving identification information from the wireless energy transmitter via a wireless communication link; Receiving voltage information from the wireless energy receiver via the wireless communication link; calculating, with a processor of the wireless energy transmitter, a coupling factor with the wireless energy receiver based at least in part on the received identification information and the received voltage information; Calculating, with the processor, an energy transfer level based on the calculated coupling factor; and Negotiate the wireless power supply contract based at least in part on the calculated power transmission level. [10] The method of claim 9, wherein the identification information specifically identifies the wireless energy receiver. [11] The method of claim 9, wherein the identification information identifies the wireless energy receiver as a member of a class of wireless energy receivers. [12] A method according to claim 9, wherein the coupling factor is calculated according to the following equation: k=C0⋅VrectVinv+VCTXpp+C1 where k is the coupling factor, Vrect is a rectifier voltage which is the received voltage information, Vinv is the DC input voltage of the inverter, VCTXpp is a peak voltage across a transmitter tuning capacitor, and C0 and C1 are matching coefficients. [13] A method according to claim 9, wherein the energy transfer level is calculated according to the following equation: Ptarget=k2⋅Cpwr where Ptarget is the energy deliverable to the receiver, k is the coupling factor, and Cpwr is a constant for a transmitter / receiver combination available for control and selected based on the received receiver identification information. [14] The method of claim 13, wherein Cpwr is stored in a memory of the controller and retrieved based at least in part on the received receiver identification information. [15] The method of claim 13, wherein Cpwr is included in the received receiver identification information. [16] A method according to claim 13, wherein Cpwr is calculated according to the following formula: Cpwr=Prect_max+RXLosskmin2 where Prect_max is the maximum total energy level required by the receiver, RXLoss is the energy lost in the receiver, and kmin is the minimum coupling coefficient corresponding to a maximum allowable shift between transmitter and receiver. [17] Wireless energy transmission device comprising: a wireless energy coil magnetically coupled to a corresponding coil of another wireless energy transmission device; and a control and a communication module that: receives identification information from the other wireless power transmission device; receives voltage information from the other wireless power transmission device; calculates a coupling factor with the other wireless power transmission device based at least in part on the received identification information and the received voltage information; calculates an energy transfer level based on the calculated coupling factor; and negotiates an energy contract with the other wireless energy transfer device based at least in part on the calculated energy transfer level. [18] The wireless power transmission device according to claim 17, wherein the identification information specifically identifies the other wireless power transmission device. [19] The wireless power transmission device of claim 17, wherein the identification information identifies the other wireless power transmission device as a member of a class of wireless power transmission devices. [20] A wireless power transmission device according to claim 17, wherein the coupling factor is calculated according to the following equation: k=C0⋅VrectVinv+VCTXpp+C1 where k is the coupling factor, Vrect is a rectifier voltage of a wireless power receiver, Vinv is a DC input voltage of an inverter of a wireless power transmitter, VCTXpp is a peak voltage across a transmitter tuning capacitor, and C0 and C1 are matching coefficients. [21] A wireless power transmission device according to claim 20, wherein: the wireless energy transmission device is the wireless energy receiver and the other wireless energy transmission device is the wireless energy transmitter; and Vinv and VCTXpp are at least part of the received voltage information. [22] A wireless power transmission device according to claim 20, wherein the power transmission level is calculated according to the following equation: Ptarget=k2⋅Cpwr where Ptarget is the energy deliverable to the wireless energy receiver, k is the coupling factor, and Cpwr is a constant for a transmitter / receiver combination available to the controller and the communication module and selected based on the received identification information. [23] The wireless power transfer device of claim 22, wherein Cpwr is stored in a memory of the controller and retrieved based at least in part on the received identification information. [24] The wireless power transmission device according to claim 22, wherein Cpwr is included in the received identification information. [25] A wireless power transmission device according to claim 22, wherein Cpwr is calculated according to the following formula: Cpwr=Prect_max+RXLosskmin2 where Prect_max is the maximum total energy level required by the receiver, RXLoss is the energy lost in the receiver, and kmin is the minimum coupling coefficient corresponding to a maximum allowable shift between transmitter and receiver. [26] A wireless power transmission device according to claim 17, wherein the power transmission level is calculated according to the following equation: Ptarget=k2⋅Cpwr where Ptarget is the energy deliverable to the wireless energy receiver, k is the coupling factor, and Cpwr is a constant for a transmitter / receiver combination available to the controller and the communication module and selected based on the received identification information. [27] The wireless power transfer device of claim 26, wherein Cpwr is stored in a memory of the controller and retrieved based at least in part on the received identification information. [28] The wireless power transmission device according to claim 26, wherein Cpwr is included in the received identification information. [29] A wireless power transmission device according to claim 26, wherein Cpwr is calculated according to the following formula: Cpwr=Prect_max+RXLosskmin2 where Prect_max is the maximum total energy level required by the receiver, RXLoss is the energy lost in the receiver, and kmin is the minimum coupling coefficient corresponding to a maximum allowable shift between transmitter and receiver.

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