ESTIMATION OF FRIENDLY METAL LOSS FOR WIRELESS POWER TRANSMISSION

Abstract

A method for estimating friendly metal losses associated with wireless power transmission from a wireless power transmitter to a wireless power receiver may involve obtaining a specification of the received power, including the rectifier voltage and rectifier current of the wireless power receiver, and calculating a friendly metal loss based on the specified rectifier voltage and rectifier current of the wireless power receiver and one or more coefficients corresponding to a wireless baseline power transmission between the wireless power transmitter and the wireless power receiver. The rectifier voltage may be a rectifier output voltage, and the rectifier current may be a rectifier output current. The calculation of the friendly metal loss may involve an equation of the form P loss = a ⋅ ITX 2 + b ⋅ I rect 2 + c ⋅ V rect 2 exhibit, where b is a coefficient relating to the rectifier current, c is a coefficient relating to the rectifier voltage, a is a coefficient relating to the transmitter current I TX refers to.

Description

BACKGROUND

[0001] Wireless power transfer is used in various electronic devices. For example, smartphones, tablet computers, smartwatches, wireless headphones, pens, etc., can use wireless power transfer to facilitate battery charging. In some applications, higher power transfer rates may be desirable, for example, to enable faster charging. At such higher power transfer levels, improved loss estimation techniques can be beneficial, including losses associated with "friendly metal" in a wireless power transmitter and / or wireless power receiver device. SUMMARY

[0002] A wireless power transmitter may include a coil of a wireless power transmitter configured to magnetically couple with a coil of a wireless power transfer unit to wirelessly transmit power to the wireless power receiver; an inverter configured to receive input power and produce an output that drives the coil of the wireless power transfer unit;Control and communication switching logic coupled to the inverter and coil of the wireless power transmitter, controlling the inverter to regulate wireless power transmission to the wireless power receiver, wherein the control and communication switching logic estimates a friendly metal loss associated with the wireless power transmission to the wireless power receiver by: receiving, from the wireless power receiver, a statement of power received, which includes a rectifier voltage and rectifier current of the wireless power receiver associated with the wireless power transmission;Calculating friendly metal power loss on the received rectifier voltage and rectifier current of the wireless power receiver and one or more coefficients corresponding to a wireless baseline power transfer between the wireless power transmitter and the wireless power receiver; and regulating the wireless power transfer to the wireless power receiver using the friendly metal power loss.

[0003] The rectifier voltage can be a rectifier output voltage, and the rectifier current can be a rectifier output current. The one or more coefficients corresponding to the wireless baseline power transfer between the wireless power transmitter and the wireless power receiver can be derived by performing a regression analysis on the received variety of power data, which includes or is derived from the corresponding rectifier voltages and rectifier currents of the other wireless power receiver associated with the other wireless power transfer, and the specific variety of measured power loss values ​​derived therefrom, in order to calculate the one or more coefficients.The one or more coefficients may include a first coefficient relating to the rectifier current and a second coefficient relating to the rectifier voltage.

[0004] Calculating the friendly metal power loss can use an equation of the following form: Ploss=a⋅ITX2+b⋅Irect2+c⋅Vrect2 where b is the first coefficient relating to the rectifier current, c is the second coefficient relating to the rectifier voltage, a is a coefficient relating to the transmitter current, and ITX is the transmitter current.

[0005] The control unit and communication switching logic can estimate the friendly metal loss by remotely receiving one or more power loss scaling factors from the wireless power receiver and calculating the friendly metal power loss in response to the one or more power loss scaling factors, wherein the one or more power loss scaling factors are based on the pairing between a wireless reference power transmitter or wireless power receiver and an actual wireless power transmitter or wireless power receiver.

[0006] The control unit and communication switching logic can estimate the friendly metal loss by remotely receiving one or more power loss scaling factors from the wireless power receiver and calculating the friendly metal power loss in response to the one or more power loss scaling factors, wherein the one or more power loss scaling factors are based on the pairing between a wireless reference power transmitter or wireless power receiver and an actual wireless power transmitter or wireless power receiver.

[0007] A procedure performed by the control logic of a wireless power transmitter or wireless power receiver to estimate friendly metal losses associated with wireless power transfer from the wireless power transmitter to a wireless power receiver may include: obtaining a specification of the received power, including the rectifier voltage and rectifier current of the wireless power receiver; calculating a friendly metal power loss based on the specification of the rectifier voltage and rectifier current of the wireless power receiver and one or more coefficients corresponding to a wireless baseline power transfer between the wireless power transmitter and the wireless power receiver; and regulating the wireless power transfer using the friendly metal power loss.where: the rectifier voltage is a rectifier output voltage and the rectifier current is a rectifier output current; and the calculation of the friendly metal power loss uses an equation of the following form:; Ploss=a⋅ITX2+b⋅Irect2+c⋅Vrect2 where b is a first coefficient relating to the rectifier current, c is a second coefficient relating to the rectifier voltage, a is a coefficient relating to the transmitter current, and ITX is the transmitter current.

[0008] The rectifier voltage can be a rectifier output voltage, and the rectifier current can be a rectifier output current. The one or more coefficients corresponding to the wireless baseline power transfer between the wireless power transmitter and the wireless power receiver can be derived by performing a regression analysis on the received set of power data and corresponding rectifier voltages and rectifier currents of the other wireless power receiver associated with the other wireless power transfer, and the specific set of measured power loss values ​​derived therefrom, to calculate the one or more coefficients.

[0009] The method may further include receiving one or more power loss scaling factors from the wireless power receiver, wherein the calculation of the friendly metal power loss may be based on the one or more power loss scaling factors, the one or more power loss scaling factors being based on the pairing between a wireless reference power transmitter or wireless power receiver and an actual wireless power transmitter or wireless power receiver.

[0010] A wireless power transmitter may include a coil of a wireless power transmitter configured to magnetically couple with a coil of a wireless power transducer to wirelessly transmit power to the wireless power receiver; an inverter configured to receive input power and produce an output that drives the coil of the wireless power transducer; and control and communication switching logic coupled with the inverter and the coil of the wireless power transducer, which controls the inverter to regulate the wireless power transmission to the wireless power receiver.The control unit and communication switching logic can estimate a friendly metal loss associated with the wireless power transmission to the wireless power receiver by receiving, from the wireless power receiver, a delivery of the received power, including the rectifier voltage and rectifier current of the wireless power receiver; calculating a friendly metal loss based on the rectifier voltage and rectifier current of the wireless power receiver and one or more coefficients corresponding to a wireless baseline power transmission between the wireless power transmitter and the wireless power receiver; and regulating the wireless power transmission to the wireless power receiver using the friendly metal loss.The rectifier voltage can be a rectifier output voltage, and the rectifier current can be a rectifier output current. Calculating the friendly metal power loss can use an equation of the following form: Ploss=a⋅ITX2+b⋅Irect2+c⋅Vrect2 where b is a first coefficient relating to the rectifier current, c is a second coefficient relating to the rectifier voltage, a is a coefficient relating to the transmitter current, and ITX is the transmitter current.

[0011] The one or more coefficients corresponding to the wireless baseline power transfer between the wireless power transmitter and the other wireless power receiver may have been derived by performing a regression analysis on the received multitude of power received data, which includes or is derived from corresponding rectifier voltages and rectifier currents of the other wireless power receiver associated with the other wireless power transfer, and the specific multitude of measured power loss values ​​derived therefrom, in order to calculate the one or more coefficients.The control unit and communication switching logic can estimate the friendly metal loss by remotely receiving one or more power loss scaling factors from the wireless power receiver and calculating the friendly metal power loss in response to the one or more power loss scaling factors, wherein the one or more power loss scaling factors are based on the pairing between a wireless reference power transmitter or wireless power receiver and an actual wireless power transmitter or wireless power receiver. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 illustrates a simplified block diagram of a wireless power transmission system. Fig. Figures 2A to 2C illustrate different configurations of an energy transmission system. Fig. Figure 3 shows a simplified flowchart of an energy calculation-based technique for foreign body detection. Fig. Figure 4 shows a flowchart of a technique for estimating friendly metal losses. Fig. Figures 5A to 5B illustrate a circuit model and the associated equations of a wireless power transmission system. Fig. Figure 6 is a circuit diagram of an illustrative wireless power system according to one embodiment. Fig. Figure 7 is a flowchart illustrating processes associated with the use of devices in wireless power systems according to embodiments. Fig. Figure 8 is a flowchart illustrating processes associated with the use of devices in wireless power systems according to embodiments. Fig. Figure 9 illustrates aspects of an ecosystem scaling arrangement for a wireless power transmission system. Fig. Figure 10 illustrates some combinations of monitorable parameters in a wireless power transmission system that can be used to estimate friendly metal loss. DETAILED DESCRIPTION

[0012] For illustrative 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 was chosen for readability and teaching purposes, and not to delimit or restrict the subject matter disclosed. Rather, the accompanying claims are provided for that purpose.

[0013] Various embodiments of the disclosed concepts are illustrated in the accompanying drawings, where identical references denote identical elements, in an exemplary and non-limiting manner. For clarity and comprehensibility, reference numerals have been repeated in the various figures where appropriate to indicate corresponding or analogous elements. Furthermore, numerous specific details are presented 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 signify at least one.A given figure may be used to illustrate the features of more than one embodiment or more than one kind of the disclosure, and not all elements in the figure may be necessary for a given embodiment or kind. A reference numeral, when provided in a given drawing, refers to the same element in all 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 for better illustration of details and features of the present disclosure. Wireless power transmission

[0014] Fig. Figure 1 illustrates a simplified block diagram of the energy transmission system 100. The energy transmission system includes an energy transmitter (PTx) 110, which wirelessly transmits energy to an energy receiver (PRx) 120 via inductive coupling 130. The energy transmitter 110 can receive input energy, 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.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.

[0015] The inverter 114 can supply the generated alternating voltage to a transmission 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 the transmission coil block 112, which may include a tuning circuit 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 transmission coil may also have a core of magnetically permeable material (e.g.,Include a ferrite) configured to influence the flux pattern of the coil in a manner suitable for the particular application. The teachings contained herein may be applied in conjunction with a variety of transmission coil arrangements suitable for a given application. In some contexts, the transmission coil 112 may be referred to as a transmit or transmitter coil. In some embodiments, a device may operate bidirectionally, i.e., wirelessly transmit or receive power, and therefore the wireless power transmission coil of such a device could be capable of transmitting or receiving power, depending on the mode of operation.

[0016] The PTx control / communication module 116 can monitor the transmission 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 seen on the Tx coil, thus 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.

[0017] As mentioned above, the control / communication module 116 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 analog, digital, and / or programmable components that may be field-programmable and updatable. The teachings herein are not limited to any particular arrangement of the control / communication circuit.

[0018] The PTx device 110 can optionally include other systems and components, such as a separate communication module 118. In some embodiments, the communication module 118 can communicate with a corresponding module tag in the PRx via the energy transfer coils. In other embodiments, the communication module 118 can communicate with a corresponding module using a separate physical channel 138.

[0019] As mentioned above, the power transmission system also includes a wireless power receiver (PRx) 120. The wireless power receiver can include a transmission coil 122, which can be magnetically coupled to the transmission coil 112 130. As with the transmission coil 112 discussed above, the Fig. Figure 1 illustrates a transmission coil block 122 that includes a tuning circuit, 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 transmission coil can also have a core of magnetically permeable material (e.g.,Include a ferrite) configured to influence the flux pattern of the coil in a manner suitable for the particular application. The teachings contained herein can be applied in conjunction with a variety of transmission coil arrangements suitable for a given application. In some contexts, the transmission coil 122 may be described as a receiving or receiving coil. In some embodiments, a device may operate bidirectionally, i.e., wirelessly transmit or receive power, and therefore the wireless power transmission coil of such a device could be capable of transmitting or receiving power, depending on the mode of operation.

[0020] The transmission coil 122 outputs an induced alternating voltage via magnetic induction through the transmission 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. Rectifier 124 can be controlled by a control / communication module 126, which operates as further described below. In various embodiments, the rectifier control 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 module can be implemented by separate control and communication modules, which communicate with each other.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.) fabricated using silicon, silicon carbide, or gallium nitride devices.

[0021] The PRx control / communication module 126 can monitor the transfer coil and use the information derived from it 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 transfer 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 / communication module 126 can be configured to vary the current drawn at the receiver side to manipulate the waveform seen on the Tx coil, thus 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.

[0022] 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 analog, digital, and / or programmable components that may be field-programmable and updatable. The teachings herein are not limited to any particular arrangement of the control / communication circuit. The PRx device 120 may optionally include other systems and components, such as a communication module (comm. module) 128. In some embodiments, the communication module 128 can communicate with a corresponding module in the PTx via the power transfer coils.In other embodiments, the communication module 128 can communicate with a corresponding module or tag using a separate physical channel 138.

[0023] Numerous variations and improvements to the wireless power transmission system 100 described above are possible, and the following teachings are applicable to any of these variations and improvements. Improved estimation of friendly metal loss

[0024] In some applications, it may be desirable to increase the power transfer rate from a wireless power transmitter to a wireless power receiver. One approach to achieving this is the use of a magnetic power profile (MPP), as defined in the Qi 2.0 specification published by the Wireless Power Consortium (WPC). MPP can utilize magnets to provide improved alignment between the respective wireless power transfer coils of the wireless power transmitter and receiver. This improved alignment can facilitate higher power transfer rates. Further aspects contributing to higher power transfer rates may include improved foreign object detection techniques and the reduction of associated losses.In some cases, the presence of a foreign object near the wireless power transmitter and / or receiver can absorb power and lead to undesirable heating of the foreign object. Mitigating these effects can be achieved using power loss accounting (PLA) techniques, which compare the power transmitted by the wireless power transmitter with the power received by the wireless power receiver to determine the power losses associated with wireless power transmission.

[0025] By modeling the expected losses for a given wireless power transmission stage, the presence of a foreign object can be inferred if the actual losses exceed the expected losses by a certain threshold. Expected losses can have various causes, including losses related to the switching logic of the wireless power transmitter and / or receiver, "friendly metal" in the enclosures or other structures of the wireless power transmitter and / or receiver, and so on. In cases where the actual losses (e.g., measured losses) exceed the expected value based on the model, mitigation techniques can be employed, such as reducing or interrupting the power transmission, providing an audible or visual indication (or other feedback) to a user, and so forth. Introduction of the friendly metal loss estimation

[0026] Exemplary modeling and estimation techniques for friendly metal loss are described in the applicant’s concurrently pending US patent application No. 18 / 166,839 entitled “Friendly Metal Loss Estimation”, which was filed on February 9, 2023, and which is hereby incorporated in its entirety by reference, and from which certain teachings are reproduced below.

[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 transmission coil 112 and the transmission coil 122 can be considered as a loosely coupled transformer. Therefore, the relative position of PTx and PRx can influence the degree of magnetic coupling between PTx and PRx, 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 transfer coil 112, and the PRx device 120 includes a transfer coil 122. In some embodiments, the PTx device 110 may be a wireless charging pad, mat, or stand (or other power transfer 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—and more specifically, their wireless power transmission coils—are horizontally aligned (as shown in the top view), 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, a slight misalignment of a 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] The shifts 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 transferred from PTx 110 to PRx 120. 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. Furthermore, a reduced degree of magnetic coupling between PTx 110 and PRx 120 can be at least partially compensated for by appropriately retuning the receiver (or transmitter) circuit. For example, one or more tuning capacitors can be included in the PTx switching logic between inverter 114 and transmission coil 112. Similarly, one or more tuning capacitors can be included in the PRx switching logic between rectifier 124 and transmission coil 122.The function of these individual capacitors is to tune the circuit by adjusting the resonant frequency of the respective circuits. They can include, for example, series resonant capacitors in series with the respective coils or parallel resonant capacitors in parallel with the respective coils, depending on the intended operating modes of the circuit. For this purpose, several selectable capacitors can be provided on one or both of the PTx 110 and PRx 120, with the appropriate tuning capacitance being selected by the respective device based on estimates of the coupling factor derived from various observable circuit parameters, such as voltages, currents, etc.

[0030] In wireless power transmission systems, it can be desirable to detect the presence of foreign objects. For example, items such as coins, keys, paper clips, etc., that come near the wireless power transmission coils can absorb some of the energy transmitted by a PTx 110, limiting the energy available to the PRx 120 and potentially inducing eddy currents in the foreign objects. Various foreign object detection (FOD) techniques can be used in wireless power transmission systems. One group of FOD techniques is based on energy accounting. The basic principle of energy accounting is as follows: the energy transmitted by the PTx 110 minus the energy received by the PRx 120 equals the "lost" energy. This lost energy can be thought of as going to one of three places. Some of the energy may be absorbed by the so-called "friendly metal" of the PTx 110.Some of the energy can be absorbed by the friendly metal of the PRx 120. Some of the energy can be absorbed by a foreign object. In this context, "friendly metal" refers to the metallic or otherwise conductive structures that make up the PTx and PRx. These can be frame or housing components, internal circuit elements, magnets, etc. These elements are referred to as "friendly metal" because their presence is known and taken into account in the design of the wireless power transmission system. Losses not related to the friendly metal can be assumed to be related to a foreign object.

[0031] Fig. Figure 3 shows a simplified flowchart of an energy calculation-based technique 330 for foreign object detection. Starting with block 331a, PTx 110 calculates the energy transferred by the PTx. This can be achieved by multiplying the output voltage of the inverter 114 by the current through the transmitting coil 112. In some implementations, the power to be transferred by the PTx is the output voltage multiplied by the current, less the losses in the transmitting coil. Furthermore, the values ​​on the output side must be used. Sometimes these values, e.g., the RMS output current, which is alternating current, may be more difficult to measure. Alternatively, the input voltage (and / or current) can be used, but then the inverter and / or coil losses can be subtracted to improve accuracy. Similarly, block 331b calculates the energy received by PTx 120.In some implementations, this can be achieved by multiplying the current through the transmission coil 122 by the input voltage of the rectifier 124.

[0032] In some applications, it may be difficult to perform these measurements on the AC side of the PRx rectifier. As an alternative, the received power can be calculated as the power from (but not in) the rectifier of PRx 120, plus the estimated losses in the rectifier and the coil 122. Additionally or alternatively, PTx-side energy measurements or estimates could be used for energy estimation. These PTx-side measurements can be based on the DC input energy of PTx 110 or an AC measurement of the output of inverter 114. In summary, the energy transmitted by PTx 110 or received by PRx 120 can be estimated either by directly measuring the current flowing through the respective wireless power transfer coil (112 / 122) or indirectly using the DC current into the transmitter or out of the receiver.The respective voltages and currents can be monitored by sensors connected to the respective control circuit in the control and communication modules 116 (for PTx 110) and 126 (for PRx 120). The implementation of such measuring systems is familiar to those skilled in the art and is therefore not repeated here.

[0033] In block 332b, PRx 120 can transmit the received energy value to PTx 110, which it receives as shown in block 332a. This explanation assumes that foreign object detection is performed by PTx 110, for example, by circuits in the control / communication module 126. However, in some applications, the foreign object detection process could be performed on PRx 120. In this case, PTx 110 could transmit its measured energy value to PRx 120. In either case, this could be done either by in-band communication (modulating the wirelessly transmitted voltage, current, frequency, phase, etc.) or out-of-band communication using separate communication modules 118 / 128 and separate communication channels 138, which could be Near Field Communication (NFC), Bluetooth, WiFi, etc., as explained above.Alternatively, instead of the calculated energy values, the device could also transmit the underlying measurements (e.g., voltage and current measurements), based on which the counterpart can calculate the respective energy.

[0034] In both cases, the PTx (or PRx, if it is performing foreign body detection) in block 333 can calculate the measured energy loss as the difference between transmitted and received energy. As mentioned above, this measured energy loss can include two components: friendly metal losses (associated with either PTx 110 or PRx 120) and foreign body losses. Therefore, the PTx (or PRx, if it is performing foreign body detection) in block 334 estimates the friendly metal losses. An exemplary technique for estimating friendly metal losses is given below with respect to Fig. 4 is explained in more detail. For the purposes of this discussion, the estimation of friendly metal losses can be viewed as a calculation based on observable circuit parameters (voltages, currents, coupling factors, etc.) and predefined parameters that relate these observable circuit parameters to the resulting losses. These parameters may be part of a model that can be derived analytically or empirically during the development of a particular power transfer device. These model parameters may be stored in a memory associated with a control unit of the respective power transfer device and either used by that device to estimate its friendly metal losses or provided to a counterpart to enable that device to estimate the friendly metal losses of its counterpart.

[0035] Once the friendly metal losses have been estimated / determined (Block 334), the foreign body detection device can calculate the net foreign body losses (Block 335), which may be the difference between the calculated measured energy loss (Block 333) and the estimated friendly metal losses (Block 334). The net foreign body losses can then be compared to a net loss threshold (Block 336). If the net foreign body losses are below the threshold, it can be assumed that no foreign body is present (Block 338) and no mitigation action is required. Alternatively, if the net foreign body losses are greater than the threshold (Block 336), it can be assumed that a foreign body is present (Block 337), and mitigation measures can be taken.Such mitigation measures may include reducing or limiting the amount of energy transmitted, interrupting the energy transmission, issuing a warning to the user, for example an audiovisual warning, etc.

[0036] In high-energy wireless power transmission systems, even relatively small losses due to foreign objects can be significant. Therefore, it is desirable to detect such losses at a level slightly below the friendly metal losses. For this reason, an accurate estimation of the friendly metal losses is desirable. For example, if the estimated friendly metal loss is higher than the actual friendly metal loss, undesirable eddy currents may be induced in a foreign object. Conversely, if the estimated friendly metal loss is lower than the actual friendly metal losses, the system may unnecessarily apply mitigation measures, such as those discussed above. These mitigation measures, however, can lead to undesirable user experiences, such as slower or completely interrupted charging, incorrect user interface messages, and so on.Furthermore, all these problems can be even more pronounced when typical wireless power levels increase from relatively low values ​​(e.g. 5W or so) to relatively higher values ​​(e.g. 20W or more).

[0037] One way to estimate friendly metal losses is to consider them as a function of the current flowing through the PTx transmitting coil 112. The friendly metal losses can be measured as a linear function of the square of the transmitting coil current, namely: PFM=αFM(ITX)2+βFM where P FM the estimated friendly metal losses are, α FM a first coefficient and β FM a second coefficient. As mentioned above, the coefficients can be derived analytically or empirically, e.g., based on a regression model that is linear in I. TX 2This model can, however, be further refined in two ways. First, a more accurate estimate of the friendly metal losses can be achieved by modeling the losses as a function of voltage rather than just current. Second, the friendly metal loss model can be modified to account for different coupling factors.

[0038] Regarding the first refinement, in addition to the transmitting coil current I TX , the DC input voltage of the inverter V In to be included to improve the friendly metal loss model. (Alternatively, the inverter output voltage or any other suitable voltage could be used.) The estimated friendly metal losses can thus be expressed as follows: PFM=αFM(ITX)2+βFM+γFMVin+δFM where P FM the estimated friendly metal losses is, α FMA first coefficient, which relates to the transmitting coil current, is γ FM a second coefficient, which relates to the inverter voltage, is and β FM & δ FM DC offset terms (coefficients) are terms that can be combined. As mentioned above, the coefficients can be derived analytically or empirically, e.g., based on a multiple regression model with two independent variables I. TX 2 (the square of the transmitting coil current) and V in the inverter input voltage (or possibly another suitable voltage, such as V) in 2 or V gl ,) is linear. This refinement can significantly improve the accuracy of friendly metal loss estimation. This is an example of a friendly metal loss estimation performed exclusively on the PTx side.

[0039] Regarding the second refinement, different model coefficients can be provided for different coupling conditions. For example, a first set of coupling coefficients can be used for high coupling conditions where the coupling factor k is above a threshold between a PTx 110 and a PRx 120, and a second set of coupling coefficients can be used for low coupling conditions where the coupling factor k is below the threshold between a PTx 110 and a PRx 120. When both the first and second refinements are applied, the estimated friendly metal losses can be expressed as follows: PFM=αFM[m](ITX)2+βFM[m]+γFM[m]Vin+δFM[m] m={0k <kth1k≥kth where P FM the estimated friendly metal losses are, αFM0,βFM0,γFM0 and δFM0 the model coefficients for a low coupling condition are, αFM1,βFM1,γFM1 and δFM1 the model coefficients for a high coupling condition are, k is a coupling coefficient and k th A threshold coupling coefficient is the boundary between the low coupling condition and the high coupling condition. In some applications, additional higher-order conditions (e.g., V) may be required. ln 2 , V ln 3 , etc.) or lower-order conditions (e.g. I TX) with corresponding coefficients are included in the model. Although the coupling conditions are defined as low and high, some implementations may use more than two coupling conditions with corresponding coefficients, such as a three-level system with low, medium, and high coupling levels and associated coefficients, or a higher number of coupling conditions with a corresponding number of coefficients.

[0040] Such an arrangement can leverage existing logic and functionality in the control circuitry of a wireless power transmitter (or receiver). As mentioned above, some power transmission devices, for example, may have control circuitry that measures certain circuit parameters (e.g., voltages and currents) and estimates a coupling factor k based on these values. The control circuitry can then select a tuning capacitor (or several) to provide appropriate circuit tuning for such a coupling factor. The same calculation can then be used to select the appropriate coefficients for the friendly metal loss estimation model.

[0041] Fig. Figure 4 shows a flowchart of Technique 440 for estimating friendly metal losses. Starting at block 441, the FOD system can measure observable parameters of the wireless power transmission system. These measurements can be performed by PTx 110 if PTx 110 implements the FOD system, or by PRx 120 if PRx 120 implements the FOD system. These observable parameters can include voltages, currents, phase shifts, frequencies, impedances, etc., in the wireless power transmission, as well as derivable parameters such as power consumption, efficiency, coupling coefficients, etc. The device implementing the FOD system can perform these measurements using suitable sensors in combination with the device's control circuitry, as explained above.

[0042] In Block 442b, a FOD system implemented by PTx 110 can receive friendly metal parameters from PRx 120 (Block 442a). If the FOD system were implemented by PRx 120, the reverse could be true. This communication can occur via either in-band or out-of-band communication, as described above. The transmitted friendly metal parameters can include model coefficients as described above and model parameters relating to current, voltage, and coupling factor. In one embodiment, PRx could send a parameter list that includes current and voltage parameters for a first coupling coefficient and current and voltage parameters for a second coupling coefficient. For wireless power transmission systems that can operate at different power transmission frequencies, it may be appropriate to include different parameters for different operating frequencies.In some applications, communication can take place according to a predefined industry standard, such as the Qi standard for wireless power transfer / wireless charging, which is promoted by the Wireless Power Consortium.

[0043] In Block 443, the FOD system can estimate the friendly metal losses based on the observations obtained in Block 441 and the parameters received from the counterpart. The FOD system may also have self-assigned friendly metal loss modeling parameters that correspond to the different coupling factors and / or operating frequencies of the friendly metal loss modeling parameters received from the counterpart. Subsequently, in Block 444, the estimated friendly metal losses can be fed back to the FOD system, such as the one described above with respect to Fig. 3 described, are transmitted for foreign body detection.

[0044] The following describes improved MPP Power Loss Accounting (MPLA) techniques that can be used to further improve the accuracy of the expected loss estimate. MPLA, as defined in the Qi v2.0 specification, made assumptions for modeling friendly metal losses (Pg). FM ) in the wireless power system. To improve accuracy, a new model for friendly metal loss is proposed to account for fluctuations in rectified voltage and current. Further discussion of friendly metal loss

[0045] Estimating MPLA power loss begins with estimating the power delivered to an external object by calculating the difference between the power transmitted by the wireless power transmitter and the power received by a wireless power receiver. In at least some embodiments, this comparison can be performed by control logic in the wireless power transmitter, although in some embodiments it may also be possible for this comparison to be performed by control logic in the wireless power receiver. In either case, the comparison can be expressed by the following equation: PFO=PPT−PPR where P FO the power radiated in a foreign object, P PT the power transmitted by the wireless power transmitter and P PRThe current received by the wireless power receiver is the power. Furthermore, the power transmitted by the wireless power transmitter can be expressed as follows: PPT=VINIIN−Pcircuit loss,TX−Pcoil loss,TX−PFM loss where V IN and I IN The input voltage and current of the inverter of the wireless power transmitter are, P Schaltungsverlust, TX P represents the circuit losses associated with the switching logic of the wireless power transmitter. Spulenverlust, TX represents the losses associated with the coil for wireless power transmission of the wireless power transmitter, and P FM-VerlustThis represents losses associated with the friendly metal of the wireless power transmitter. As mentioned above, "friendly metal" refers to metallic or other conductive structures associated with the wireless power transmitter and receiver devices themselves, such as housings, internal structures, etc. Similarly, the power received by the wireless power receiver can be expressed as follows: PPR=VRECTIRECT+Pcircuit loss,RX+Pcoil loss,RX where V GL and I GL The output voltage and current of the rectifier of the wireless power receiver are, P Schaltungsverlust, RX P represents the circuit losses associated with the circuit of the wireless power receiver. Spulenverlust, RX represents losses that are attributed to the coil for wireless power transmission of the wireless power receiver.

[0046] In some applications, various improvements in wireless power transmission can be achieved by varying the rectifier voltage VGL, i.e., the output voltage of rectifier 124 in the wireless power receiver. (See, for example, 124; Fig. 1) In such cases, it may be desirable to broaden the concept of friendly metal loss, P FM loss , to account for the variability of the rectified voltage and current (V RECT and I RECT The friendly metal loss can be expressed, for example, as follows: PFM loss=gFM,ITX αFM,ITX ITX2+gFM,IRECT αFM,IRECT IRECT2+gFM,VRECT αFM,VRECT VRECT2 where g FM, ITX , S FM,IRECT and g FM,VRECT Ecosystem scaling terms are (as described in more detail below) and α FM,ITX , α FM,IRECT and α FM,VRECTCoefficients are those relating to the electrical and magnetic circuit parameters (physical and / or equivalent) that characterize the wireless power transmission system. Such coefficients can be described in various ways, some of which are described in more detail here. More generally, friendly metal losses can be modeled in the following form: PFM=a⋅ITX2+b⋅IRECT2+c⋅VRECT2 where P FM the estimated friendly metal losses are, I TX the direct current into the inverter of the wireless power transmitter is, I GL the direct current from the rectifier of the wireless power receiver is and V GLThe DC output voltage of the wireless power receiver's rectifier is given by where a, b, and c are matching coefficients that characterize the specific wireless power transmission system. The model described above does not require a DC bias term, as some earlier techniques did, to account for power losses.

[0047] Fig. 5A and Fig. Figure 5B illustrates a derivation of the model described above. More specifically, it presents Fig. Figure 5A represents an equivalent circuit 500, which can be used to model the wireless power transmission system. In the equivalent circuit 500, the input voltage of the inverter is represented by the voltage source Vin, and the load of the wireless power receiver is represented by the resistor R. L depicted. The wireless power transmitter current i TX flows through: Capacitance C TX, which represents the tuning capacitance of the wireless power transmitter; resistance R LEIT_TX , which represents line losses associated with the switching logic of the wireless power transmitter; resistance R SPULE_TX , which represent losses in the coil for wireless power transmission of the wireless power transmitter; resistance R FM_TX , which represents friendly metal losses associated with metallic or other conductive structures in the wireless power transmitter; and inductance L TX_LK , which represents the stray inductance of the coil for wireless power transmission of the wireless power transmitter. The wireless power transmitter current i TX This can then be split into magnetizing current i M and receiver current i RX to be modeled. Magnetization current i M flows through the inductance L M and resistance R M, which represent the magnetization effects of the coils in wireless power transmission. Receiver current i RX flows through the inductance L RX_LK , which represents the stray inductance of the coil for wireless power transmission of the wireless power receiver; R FM_RX , which represents friendly metal losses associated with metallic or other conductive structures in the wireless power receiver; R SPULE_RX , which represents losses in the coil for wireless power transmission of the wireless power receiver; resistance R LEIT_RX , which represents line losses associated with the wireless power receiver circuitry; and capacitance C RX, which represents the tuning capacity of the wireless power receiver. Instead of specific physical devices, the circuit elements described above can be representative of such devices and / or aggregated parameters that represent or model multiple physical components or structures.

[0048] With further reference to Fig. Equations 501 describe the interrelationships between the various circuit elements and parameters of the equivalence circuit model 500. These equations can be combined to generate equations 502. Then, with further reference to Fig. 5B is further manipulated to produce equation 503, which calculates the losses with respect to VRECT2 and IRECT2 expresses a form similar to equations 4 and 5 above.

[0049] While the above description represents the friendly metal losses in relation to the transmitter current squared (ITX2), the receiver rectifier voltage squared (VRECT2) and receiver rectifier current squared (IRECT2) While such losses can be modeled in other ways, based on other orders of such variables, such as the transmitter current (I TX ), rectifier voltage (V GL ) and rectifier current (I GL ) and / or can be modeled in conjunction with other voltages, currents or other circuit parameters.

[0050] Further aspects of power loss consideration, including losses due to friendly metals, in relation to the rectifier voltage V GL and rectifier current I GLare described in the applicant’s concurrently pending US patent application No. 18 / 617,103 entitled “Power Transfer Accounting for Wireless Power Transfer”, which was filed on March 26, 2024 and which is hereby incorporated in its entirety by reference thereto. Ecosystem scaling

[0051] The accuracy of friendly metal loss estimation can vary depending on the different possible wireless power transmitter and receiver pairings. In some implementations, baseline values ​​and / or settings (such as scaling coefficients, offsets, etc.) for different wireless power transmitter and receiver pairs can be determined, for example, during manufacturing, and stored in one or more of the wireless power transmitter and receiver devices. However, as the number of possible transmitter-receiver pairs increases, this can quickly become impractical. Therefore, it may be desirable to provide one or more baseline value pairs for each transmitter based on one or more "reference" or "golden" receiver pairs.Each receiver can then be characterized relative to one or more of the reference / gold receivers and provided with its own stored values ​​according to this characterization. For example, this could be implemented as a variety of scaling factors with respect to the reference / gold receiver(s). Subsequently, a wireless power receiver could provide its scaling factors to the wireless power transmitter, which could then adjust its friendly metal estimates based on the stored reference values ​​and the scaling factors that account for differences in the magnetic parameters of specific wireless power transmission devices, such as the inductance (L) of the wireless power transmission coils, the quality factor (Q) of the coils, etc.

[0052] Exemplary techniques for scaling loss measurement are described in the applicant's US patent application 17 / 681,363 entitled "Wireless Power Systems with Shared Inducive Loss Scaling Factors", which was filed on February 25, 2022, and is incorporated herein in its entirety by reference, with certain lessons therefrom being reproduced below.

[0053] To accurately estimate losses, various potential loss sources in a wireless power system should be considered. Some power losses from transmitters and receivers are independent of the magnetic properties of the transmitters and receivers (e.g., switching losses, losses dependent on the drain-source resistance of field-effect transistors in the inverters and rectifiers, etc.). Losses such as these can be accounted for by characterizing relevant device components (e.g., by determining the drain-source resistances of transistors using measurements taken during manufacturing and / or other testing).

[0054] Transmitters and receivers also exhibit power losses that depend on their inductive properties (e.g., losses dependent on the magnetic properties of coupled transmitters and receivers, sometimes referred to as coverage losses, inductive losses, magnetic losses, etc.). Examples of power losses dependent on the magnetic properties of transmitters and receivers include: 1) coil losses, which depend on the AC resistances of the covered transmission coils; 2) friendly metal losses (e.g., power losses due to eddy currents induced in the metal casing of a receiving device); and 3) foreign object losses, which occur when a foreign object is present between a transmitter and a receiver.Power losses such as these, which depend on the magnetic properties of the transmitter and receiver, can sometimes be characterized by magnetic LQK parameters, where L refers to the inductance of the transmission coils, Q refers to the quality factor of the coils, and K refers to the magnetic coupling of the coils.

[0055] In a wireless power ecosystem with numerous different transmitters and receivers, each pairing between a given transmitter and receiver results in potentially different magnetic properties. This poses a challenge for accurately assessing power losses, which depend on the magnetic characteristics of a coupled transmitter / receiver pair. To facilitate accurate power loss estimations of transmitters and receivers, their magnetic power loss parameters can be determined by using measurements between different transmitter and receiver models and reference units (e.g., reference transmitters and reference receivers).Characteristic information from measurements performed with reference transmitters and / or reference receivers can be stored in each different device model and subsequently used to ensure accurate power loss estimates when a particular model of transmitter is paired with a particular model of receiver.

[0056] Fig. Figure 6 shows an illustrative wireless power switching logic in a wireless power transmission system 608 in an illustrative scenario where a wireless power transmitter is paired with a wireless power receiver. In some examples, the system 608 implements the design of the wireless power transmission system 100, which is described above with reference to Fig. 1 was discussed. The wireless power switching logic of Fig. 6 includes a wireless power transmission switching logic 652 in the wireless power transmission device 612 and a wireless power reception switching logic 654 in the wireless power reception device 624. During operation, wireless power signals 644 are transmitted by the wireless power transmission switching logic 652 and received by the wireless power reception switching logic 654. The configuration of Fig. Figure 6 includes a single transmission coil 636 and a single transmission coil 648 (as an example). In other implementations, the voltage across the capacitor 670 is measured, and the current through the coil is derived from this measurement.

[0057] As in Fig. As shown in Figure 6, the wireless power transmission switching logic 652 includes an inverter switching logic 661. The inverter switching logic (inverter) 661 can be used to provide signals to the coil 636. During wireless power transmission, the control switching logic of the device 612 supplies signals to a control input 682 of the inverter 661, causing the inverter 661 to supply AC drive signals to the coil 636. Circuit components such as the capacitor 670 can be connected in series with the coil 636, as shown in Figure 6. Fig. Figure 6 shows that the measuring switching logic 641 in the device 612 can perform measurements of the operating currents and voltages of the device 612. For example, a voltage sensor 641A can be used to measure the coil voltage across the coil 636, and a current sensor 641B can be used to measure the coil current through the coil 636.

[0058] When alternating current signals are supplied to coil 636, corresponding electromagnetic alternating current signals (wireless current signals 644) are transmitted to nearby coils, such as the illustrative coil 648 in the wireless power receiving switching logic 654. This induces a corresponding alternating current signal (AC current signal) in coil 648. Capacitors, such as capacitors 672, can be connected in series with coil 648. The rectifier 650 receives the AC current from coil 648 and generates corresponding direct current power (e.g., DC voltage Vcf) at the output terminals 676. This power can be used to supply power to a load. The measuring switching logic 643 in device 624 can perform measurements of the operating currents and voltages of device 624.For example, a voltage sensor 643A can measure the output voltage of rectifier 650, or a voltage sensor can measure the coil voltage at coil 648. The current sensor 643B can measure the rectifier output current of rectifier 650, or a current sensor can measure the current in coil 648.

[0059] The measurements performed by the measurement switching logic 641 and 643 can be processed to extract magnetic loss characteristics (e.g., coefficients or other parameters that characterize the magnitude of power losses in devices 612 and 624 and that depend on the magnetic properties of the transmitter and receiver). These measurements can be stored within each device and exchanged between the devices, so that device 612 (and, if desired, device 624) can use this information to accurately estimate the operating conditions of a wireless power transmission system and its power losses.

[0060] For example, these measurements can be used to estimate how well the transmitter and receiver are able to transmit wireless power and, consequently, whether a user should be informed that the wireless power transmission operations are proceeding normally. As another example, these measurements can be used to estimate a magnetic coupling coefficient k, the efficiency of the wireless power transmission, the estimated power loss, and / or other attributes of the paired transmitter-receiver pair. Additionally, or instead of estimating the power loss to determine whether a foreign object is present and therefore whether to continue with the wireless power transmission, the System 608 can use this information (e.g.,The estimated foreign object power loss and / or related coupling and / or effect information are used to determine whether to display an acknowledgment message to the user of System 608 to inform the user that the wireless power transfer is proceeding properly (e.g., to inform the user that this process has not been thwarted by the presence of poor coupling due to the presence of a foreign object, possible misalignment, or other factors). Example acknowledgment messages include an audio output, such as a beep, and / or a visual output displayed on Device 624 to reassure the user that charging is proceeding normally.

[0061] An example should be noted where, after measurements with the switching logic 641 and 643, the following equation can be used to determine how much power is potentially absorbed by a foreign object in system 10: PFO=PIN−POUT−PLOSSTX−PLOSSRX

[0062] In Equation 6, PFO represents the amount of power absorbed by any foreign object present (if any). POUT represents the output power (e.g., the output power of rectifier 650), PPIN represents the input power (e.g., the input power of coil 636), PLOSSTX represents the power loss attributable to wireless power transmitter 612, and PLOSSRX represents the power loss attributable to wireless power receiver 624. The values ​​of POUT and PIN can be measured (e.g., using switching logic 641 and 643). As discussed above with reference to Equations 2 and 3, power losses attributable to devices 612 and / or 624 may also include losses due to friendly metals.Mathematical models can be used to create relational expressions for PLOSSTX and PLOSSRX, and these expressions can be evaluated using measured operating parameters such as those obtained using switching logic 641 and 643. For example, in an illustrative embodiment, PLOSSTX and PLOSSRX can be calculated using equations 7a and 8a, respectively. PLOSSTX=b*RAIRTX*(ITX)2 PLOSSRX=m*RAIRRX*(IRX)2+α∗(IRX)2+αDC

[0063] In equations 7a and 8a, ITX represents the transmitter current (e.g., the coil current) and IRX the receiver current (e.g., the rectifier output current or, in some embodiments, the transmission coil current). The values ​​of RAIRTX and RAIRRX represent the measured AC coil resistances for coils 636 and 648, respectively. The values ​​of b, m, α, and αDC are model parameters (sometimes called magnetic power loss coefficients) that characterize the performance of the coupled transmitter / receiver pair in system 608.In this example, the transmitter power loss PLOSSTX due to the transmission coil power loss is in the model of Equation 7a, and the receiver power loss PLOSSRX has a first component due to the transmission coil power loss (the first term of Equation 8a) and a second component (composed of the last two terms of Equation 8a) representing friendly metal losses (e.g., losses due to eddy currents induced in the receiver during power transfer). The parameter b is sometimes referred to as the transmitter transmission coil loss parameter or coefficient. The parameter m can also be referred to as the transmission coil loss parameter or coefficient, and the parameters α and αDC can also be referred to as friendly metal loss parameters or coefficients.The parameters b, m, α and αDC depend on the magnetic interactions between the devices 612 and 624 when they are coupled, and can therefore sometimes be referred to as magnetic loss parameters or magnetic loss coefficients.

[0064] In an ecosystem where a user has access to several different models of wireless power transmission devices (e.g., different models of Device 612) and several different models of wireless power receiving devices (e.g., different models of Device 624), the magnetic loss parameters vary depending on which specific transmitters and receivers are paired. For example, when a Model I transmitter and a Model J receiver are paired, the magnitude of power loss in each device differs from that which occurs when these devices are paired with other devices. To account for these variations, equations 7a and 8a can be replaced by equations 7b and 8b, respectively. PLOSSTX=gb*bR*RAIRTX*(ITX)2 PLOSSRX=gm*mR*RAIRRX*(IRX)2+gα*αR*(IRX)2+gαDC*αRDC

[0065] In Equation 7b, the transmitter transfer coil loss parameter b is replaced by a reference transmitter transfer coil loss value bR (sometimes called the transmitter transfer coil loss coefficient), which is associated with the transmitter loss measured when a reference transmitter is coupled to a reference receiver, and this value is then scaled using the scaling factor gb. In Equation 8b, the receiver transfer coil loss parameter m is replaced by mR (sometimes also called the receiver transfer coil loss coefficient), which is associated with the receiver transfer coil loss measured when a reference receiver and a transmitter are coupled, and this value is then scaled using the scaling factor gm.In Equation 8b, the friendly metal loss parameters α and αDC are each replaced by the friendly metal loss parameters (coefficients) αR and αRDC, which were obtained from measurements using a reference transmitter and a reference receiver. The friendly metal loss reference parameters are scaled by the corresponding scaling factors gα and gαDC. By using scaling factors when calculating PLOSSTX (see, for example, Equation 2b) and PLOSSRX (see, for example, Equation 3b), Equation 6 can be satisfactorily evaluated over various permutations of pairings of wireless power transmitter and receiver models.

[0066] Illustrative processes involved in using measurements from wireless power transmitters and receivers to determine their scaling parameters are shown in the flowchart of Fig. 7 shown. The processes in Fig. Seven operations are performed at design time, and the resulting scaling factors are stored in production units. Illustrative operations involved in using the scaling parameters in System 608 are described in Fig. 8 shown. The processes in Fig. 8 are performed at runtime (e.g., when the transmitter and receiver are paired in preparation for wireless power transmission). In the examples of Fig. 7 and Fig. Section 8 assumes that the scaling factors for a specific model of transmitter (a Model I transmitter) and a specific model of receiver (e.g., a Model J receiver) are obtained using reference device measurements and subsequently used when a Model I transmitter is paired with a Model J receiver. In general, this process is expected to be performed for numerous transmitter models (models other than Model I) and numerous receiver models (models other than Model J). Furthermore, in general, any of the various characterized transmitter models can be paired by a user with any of the various characterized receiver models. This is because not all users have the same transmitter model, and not all users have the same receiver model. In the present example, a user pairs [the transmitter model] during the operations in [section / section]. Fig. 8 a transmitter of type I with a receiver of type J.

[0067] The processes involved in measuring the scaling factors for the magnetic power losses of a Model I transmitter and a Model J receiver are described in Fig. Figure 7 illustrates this process. During the Block 790 operations, a wireless reference power receiver device is paired with a wireless reference power transmitter device (physically or via simulated pairing, such as a finite element analysis simulation). Physical reference devices can be obtained from a central source or constructed by various device manufacturers according to a universally distributed reference design. After pairing, the reference transmitter and receiver can begin transmitting power. Specifically, during the Block 790 operations, the reference transmitter can send wireless power signals to the reference receiver while the internal operating parameters (e.g., transmitter and receiver currents and voltages) are measured and recorded. From these measurements, the magnetic reference loss parameters (e.g.,(the values ​​of the magnetic reference loss parameters bR, mR, αR, and αRDC are obtained). In scenarios where pairing simulations are used instead of measurements on physically paired devices, finite element analysis simulation is used to determine the LQK of the paired transmitter / receiver pair, and then circuit simulations are used to determine the expected currents and voltages. These simulated currents and voltages can then be used to determine the magnetic loss parameters.

[0068] After the magnetic reference loss parameters have been determined (either by physical measurements or simulations), a Model J receiver is paired with a reference transmitter. While these devices are being paired in a simulation, or while they are being physically paired and wireless power is being transmitted from the reference transmitter to the Model J receiver, loss parameter measurements for the Model J receiver can be obtained. Specifically, during the operations of Block 792, the Model J loss parameters (coefficients) bRj, mRj, αRj, and αRjDC are obtained. The "J" in each of these parameters and the "R" (for "reference") in each of these parameters indicate that the loss parameters are specific to a scenario in which a Model J receiver is operated with a reference transmitter.The scaling factor gb (Equation 7b) for the Model J receiver can then be calculated using Equation 9 and stored in Model J wireless power receiver devices (e.g., during manufacturing or later using an update). gb=bRj / bR

[0069] During the operations of Block 794, a Model I transmitter is paired with a reference receiver. Power is transmitted wirelessly while the transmitter operating parameters (e.g., currents and voltages) are measured. From these measurements or simulations, the magnetic loss parameters miR, biR, αiR, and αiRDC for the Model I transmitter are obtained. Using equations 10, 11, and 12, the scaling factors gm, gα, and gαDC for the Model I transmitter are then calculated. gm=miR / mR gα=αiR / αR gαDC=αiRDC / αRDC

[0070] The scaling factors for the Model I sender are then stored in Model I senders (e.g., during manufacturing or later using an update). Illustrative procedures for using the scaling factors for a Model I sender and a Model J receiver in a scenario where a user pairs a Model I sender and a Model J receiver are shown in the flowchart in Fig. 8 shown. During the processes of Fig. 8. A user who wants to wirelessly transfer power from the Model I transmitter to the Model J pairs the Model I transmitter and the Model J receiver during the operations of Block 800 (e.g., by magnetically attaching a Model I charging puck to a Model J mobile phone, to give just one example).

[0071] During the operations of Block 802, the Model I transmitter and the Model J receiver exchange information such as their scaling factors (e.g., using low-power in-band communication or other wireless communication) and the type of power transmission. For example, at Block 792, the Model J receiver transmits the value of the scaling factor gm, obtained from the Model J measurements with the reference transmitter. Fig. 7 to the Model I transmitter. The Model I transmitter sends the values ​​of the scaling factors gm, gα, and gαDC, which are derived from the Model I measurements with the reference receiver in block 794 of the Fig. 7 were received, to the recipient of model J.

[0072] During wireless power transmission from the Model I transmitter to the Model J receiver, the 641 measurement switching logic in the transmitter and the 643 measurement switching logic in the receiver can measure the operating parameters of the transmitter and receiver (e.g., coil currents and voltages, rectifier output voltage and current, etc.). Current and voltage measurements can be exchanged between the transmitter and receiver as desired (e.g., using in-band wireless communication). The information measured by the 641 and 643 switching logics, in conjunction with the exchanged scaling factors, can be used to calculate PLOSSRX and PLOSSTX using equations 7b and 8b.

[0073] For example, during the operations of Block 804, the Model J receiver can measure the rectifier current and rectifier voltage (whose product is POUT) and use these measurements, in conjunction with the scaling factors gm, gα, and gαDC received from the Model I transmitter during the operations of Block 802, to evaluate Equation 8b and thereby estimate PLOSSRX. The scaling factors received from the Model I transmitter provide receiver J with information about the expected operating characteristics of the Model I transmitter with respect to receiver transmission coil loss and friendly metal loss.

[0074] As an example, consider the receiver transmission coil loss. If receiver J were coupled to a reference transmitter, the value of the scaling factor gm would be 1.0. The receiver could then use the first term in equation 8b to determine the receiver transmission coil loss (where the receiver transmission coil loss is 1.0*mR*RAIRRX*(IRX)²), with the values ​​of mR, RAIRRX, and the receiver current IRX being known to the receiver. In this case, however, receiver J is not coupled to a reference transmitter but to transmitter I. Transmitter I might have been previously determined to cause lower coil losses than the reference transmitter for covered receivers, so the value of gm passed on by transmitter I to the model J receiver during block 802 could be 0.9 (for example).When the Model J receiver evaluates Equation 8b using the scaling factor of 0.9 received from the Model I transmitter, the Model J receiver estimates a slightly reduced value of PLOSSRX (due to the presence of the Model I transmitter, which is known to cause lower receiver transmission coil losses than the reference transmitter). As this example demonstrates, by using scaling factors received from the Model I transmitter, the magnetic loss parameters used by the receiver to calculate PLOSSRX can be scaled to reflect the presence of a Model I transmitter instead of a reference transmitter, thus improving the accuracy with which the value of PLOSSRX is estimated.

[0075] During the operations of Block 806, the Model I transmitter uses measurements of the measured transmitter transfer coil current ITX, the known values ​​of bR and RAIRTX, and the scaling factor gb received from the receiver when evaluating Equation 7b to estimate PLOSSTX. The scaling factor gb reflects how Model J receivers are expected to affect transmitter transfer coil loss in transmitters paired with Model J receivers rather than reference receivers. For example, Model J receivers may tend to exhibit higher transmitter transfer coil loss with paired transmitters than with reference receivers. Consequently, the value of the scaling factor gb received by the Model I transmitter from the Model J receiver may be 1.1 (for example).When evaluating equation 7b, this increased scaling factor helps transmitter I to take into account that the model I transmitter is coupled to a model J receiver and therefore has higher transmitter transmission coil losses than when coupled to a reference receiver.

[0076] During the operations of Block 807, the value of PLOSSRX, calculated at Block 804, can be sent to the paired transmitter. During the operations of Block 808, System 608 evaluates the value of PFO using Equation 6 (e.g., an estimate of foreign object power loss, if any, is made). By accurately estimating PLOSSTX using the scaling factor information used by the Model J receiver and by receiving the estimated value of PLOSSRX from the Model J receiver, the Model I transmitter will have both PLOSSTX and PLOSSRX for Equation 6. The value of PIN can be obtained by the transmitter by calculating the product of the transmitter transmission coil current (ITX) and the voltage from the measurement switching logic 641.The value of POUT can be obtained by the transmitter by calculating the product of the rectifier output current IRX and the rectifier output voltage received by the 643 measurement logic, or POUT can be received by the receiver.

[0077] After the PFO value has been determined during the operations of Block 808, the transmitter can compare PFO to a power loss threshold (TH) (Block 810). System 608 can then take appropriate action. For example, in response to a determination that PFO is less than TH, it can be inferred that no foreign object is present, and power transfer operations can continue normally (e.g., allowing power to be transferred to charge battery 658). In response to a determination that PFO is greater than TH, power transfer operations can be restricted. Examples of power transfer restrictions that can be implemented include foregoing all power transfer operations and / or stopping power transfer if it is already underway, limiting the maximum amount of power that can be transferred (e.g.,to a predetermined, relatively low power level below the normal maximum power transfer capabilities of System 608), and / or the output of a visual, audible, and / or vibratory alarm signal to a user. If desired, alarm calls for a user (e.g., warnings and / or other informational content informing the user that the power transfer operations are not proceeding normally because a foreign object has been detected) can be displayed using output devices in Device 612 and / or Device 624. For example, the control switching logic in Device 612 can communicate wirelessly with the control switching logic in Device 624 to output a visual alarm call that is displayed on a screen in Device 624. Further discussion on ecosystem scaling

[0078] In an ecosystem where a user has access to multiple different models of wireless power transmission devices and multiple different models of wireless power receiving devices (e.g., different models of both devices), the parameters for electrical and / or magnetic loss can vary depending on which specific wireless power transmitter and wireless power receiver are paired. For example, when a Model I transmitter and a Model J receiver are paired, the amount of power loss in each device will differ from that which occurs when these devices are paired with other devices.

[0079] To account for these fluctuations and thereby ensure an accurate estimation of friendly metal, foreign objects, and / or other losses, scaling factors for the magnetic power loss parameters (sometimes referred to as power loss coefficient scaling factors) can be used. By employing such scaling factors when calculating various parameters, the loss equations can be satisfactorily evaluated regardless of which transmitter and receiver models are paired. The exchange of such scaling parameters between different wireless power transmission devices can be considered "ecosystem scaling," as it expands the "ecosystem" of devices that can work together to provide wireless power transmission and foreign object detection.Such ecosystem scaling can be extended to the context of estimating friendly metal losses described above.

[0080] Techniques for performing ecosystem scaling to estimate friendly metal losses can include various aspects that are in Fig. 9 are shown.

[0081] Starting with diagram 901 of Fig. 9. On the wireless power transmitter (PTx) side, various gain factors g can be calculated for different parameters, based on pairings between a wireless “golden” or “reference” power transmitter GTx and wireless power receiver GRx, and the actual wireless power transmitter PTx and wireless power receiver PRx. More specifically, scaling or proportionality factors (a) can be used to scale a measurement GG between the golden or reference transmitter GTx and the golden or reference receiver GRx to be equivalent to a measurement GR between the golden transmitter GTx and the actual receiver PRx.Similarly, scaling or proportionality factors (b) can be used to scale a measurement TR between the actual wireless power transmitter PTx and the actual wireless power receiver PRx so that it lies between the actual power transmitter PTx and the golden wireless power receiver GRx. As shown in the equation below Diagram 901, a gain with respect to the wireless power transmission coil g can be applied. coil,TX calculated to a value that can be stored on the wireless power transmitter.

[0082] As shown in diagram 902 of Fig. As illustrated in Figure 9, the scaling of the wireless power receiver can proceed in a similar manner. More specifically, different gain factors g can be calculated for different parameters based on pairings between a wireless “golden” or “reference” power transmitter GTx and wireless power receiver GRx, and the actual wireless power transmitter PTx and wireless power receiver PRx. More specifically, scaling or proportionality factors (a) can be used to scale a measurement GG between the golden or reference transmitter GTx and the golden or reference receiver GRx to be equivalent to a measurement TG between the golden receiver GRx and the actual transmitter PTx.Similarly, scaling or proportionality factors (b) can be used to scale a measurement TR between the actual wireless power transmitter PTx and the actual wireless power receiver PRx so that it lies between the actual power receiver PRx and the golden wireless power transmitter GTx. As shown in the equation below Diagram 902, a gain with respect to the wireless power receiver coil g can be applied. coil,RX a value can be calculated that can be provided and / or stored on the wireless power transmitter and the wireless power receiver. Similarly, ecosystem scaling gain parameters can be calculated for the coefficients described above, which are based on estimating friendly metal loss based on the transmitter current (g). FM , ITx ), rectifier current (g FM,IGL ) and rectifier voltage (g FM,VGLThese enhancement parameters for ecosystem scaling can be calculated by and remain with the wireless power transmitter, although in some embodiments they can also be calculated and / or provided by the wireless power receiver.

[0083] Fig. Figure 10 illustrates a Table 1000 that presents some combinations of monitorable parameters in a wireless power transmission system that can be used to estimate friendly metal loss. Usable parameters include a DC modeling parameter (DC), the transmitter current (squared), and ITX. 2 , Rectifier current (squared) IGL 2 Inverter input voltage (Vin) and rectifier voltage (squared) VGL 2The above description focused on the combination shown in row 1041 of Table 1000, using the squared transmitter current, the squared rectifier current, and the squared rectifier voltage. However, the inventors have experimented with models containing two to four of the variables in various combinations, as shown in rows 1042 to 1051, and have observed different levels of accuracy for different models, depending on the specific implementation. Therefore, for a given implementation, it may be desirable to use one or more models that include different combinations of such variables, depending on the application. In any case, model equations can be selected and appropriate coefficients fitted based on power transmission measurements, as described above and in the integrated applications.

[0084] The above describes various features and embodiments relating to improving the estimation of friendly metal losses for the purpose of enhancing wireless power transmission in wireless power transmission systems. Such arrangements can be used in a variety of applications, but may be particularly advantageous when used in conjunction with electronic devices such as mobile phones, tablet computers, laptops, or notebook computers, and accessories such as wireless headphones, pens, etc. Although numerous specific features and various embodiments have been described, it is further understood that the various features and embodiments may be combined into different implementations within a given design, unless otherwise stated that they are mutually exclusive.Therefore, the various embodiments described above are provided for illustrative purposes only 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.

[0085] The foregoing describes exemplary embodiments of wireless power transfer systems capable of transmitting certain information between the PTx and PRx within the system. This disclosure provides that this information transfer enhances the devices' ability to efficiently provide each other with wireless power signals to support battery charging, such as by sharing the ecosystem scaling parameters of the devices. Entities implementing this technology should ensure that, to the extent that sensitive information is used in specific implementations, established data protection policies 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.

[0086] Implementers should inform users when identifiable personal information is likely to be transmitted in a wireless power transmission 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. 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 18 / 166,839

[0026] US 18 / 617,103

[0050] US 17 / 681,363

[0052] Cited non-patent literature

[0000] Power Transfer Accounting for Wireless Power Transfer” described on March 26, 2024

[0050] Wireless Power Systems with Shared Inducive Loss Scaling Factors”, published on February 25, 2022

[0052]

Claims

[1] Wireless power transmitter, comprising: a coil of a wireless power transmitter configured to magnetically couple with a coil of a wireless power transmitter to wirelessly transmit power to the wireless power receiver; an inverter configured to receive input power and generate an output that drives the coil of the wireless power transmitter; and Control unit and communication switching logic coupled to the inverter and the coil of the wireless power transmitter, which controls the inverter to regulate the wireless power transmission to the wireless power receiver, wherein the control unit and communication switching logic estimates a friendly metal loss associated with the wireless power transmission to the wireless power receiver by: Receiving a specification of the received power, which includes the rectifier voltage and rectifier current of the wireless power receiver associated with the wireless power transmission; Calculating the power loss of friendly metal at the received rectifier voltage and rectifier current of the wireless power receiver and one or more coefficients corresponding to a wireless baseline power transfer between the wireless power transmitter and the wireless power receiver; and Regulating wireless power transmission to the wireless power receiver using the power loss of friendly metal. [2] Wireless power transmitter according to claim 1, wherein the rectifier voltage is a rectifier output voltage and the rectifier current is a rectifier output current. [3] Wireless power transmitter according to claim 1, wherein the control unit and communication switching logic, wherein one or more coefficients corresponding to the wireless baseline power transfer between the wireless power transmitter and the wireless power receiver, were derived by: Performing a regression analysis on the received multitude of power received data, which includes or is derived from the corresponding rectifier voltages and rectifier currents of the other wireless power receiver associated with the other wireless power transmission, and the determined multitude of measured power loss values ​​derived therefrom, in order to calculate one or more coefficients. [4] Wireless power transmitter according to claim 3, wherein the one or more coefficients include a first coefficient with respect to the rectifier voltage and a second coefficient with respect to the rectifier current. [5] Wireless power transmitter according to claim 4, wherein an equation of the following form is used to calculate the power loss of the friendly metal: Ploss=a⋅ITX2+b⋅Irect2+c⋅Vrect2 where b is the first coefficient relating to the rectifier current, c is the second coefficient relating to the rectifier voltage, a is a coefficient relating to the transmitter current, and I TX The transmitter current is. [6] Wireless power transmitter according to claim 5, wherein the control unit and communication switching logic estimates the friendly metal loss by further receiving one or more power loss scaling factors from the wireless power receiver and calculating the friendly metal power loss in response to the one or more power loss scaling factors, wherein the one or more power loss scaling factors are based on the pairing between a wireless reference power transmitter or wireless power receiver and an actual wireless power transmitter or wireless power receiver. [7] Wireless power transmitter according to claim 1, wherein an equation of the following form is used to calculate the power loss of the friendly metal: Ploss=a⋅ITX2+b⋅Irect2+c⋅Vrect2 where b is a first coefficient relating to the rectifier current, c is a second coefficient relating to the rectifier voltage, a is a coefficient relating to the transmitter current, and I TX The transmitter current is. [8] Wireless power transmitter according to claim 7, wherein the control unit and communication switching logic estimates the friendly metal loss by further receiving one or more power loss scaling factors from the wireless power receiver and calculating the friendly metal power loss in response to the one or more power loss scaling factors, wherein the one or more power loss scaling factors are based on the pairing between a wireless reference power transmitter or wireless power receiver and an actual wireless power transmitter or wireless power receiver. [9] Wireless power transmitter according to claim 1, wherein the control unit and communication switching logic estimates the friendly metal loss by further receiving one or more power loss scaling factors from the wireless power receiver and calculating the friendly metal power loss in response to the one or more power loss scaling factors, wherein the one or more power loss scaling factors are based on the pairing between a wireless reference power transmitter or wireless power receiver and an actual wireless power transmitter or wireless power receiver. [10] Method performed by the control switching logic of a wireless power transmitter or a wireless power receiver to estimate friendly metal losses associated with the wireless power transmission from the wireless power transmitter to a wireless power receiver, the method comprising: Receiving an indication of the received power, including rectifier voltage and rectifier current of the wireless power receiver; and Calculating a friendly metal power loss based on the specified rectifier voltage and rectifier current of the wireless power receiver and one or more coefficients corresponding to a wireless baseline power transfer between the wireless power transmitter and the wireless power receiver; and Regulating wireless power transmission using friendly metal power loss; where: The rectifier voltage is a rectifier output voltage, and the rectifier current is a rectifier output current; and The calculation of the friendly metal power loss uses an equation of the following form: Ploss=a⋅ITX2+b⋅Irect2+c⋅Vrect2 where b is a first coefficient relating to the rectifier current, c is a second coefficient relating to the rectifier voltage, a is a coefficient relating to the transmitter current, and I TX The transmitter current is. [11] Method according to claim 10, wherein the rectifier voltage is a rectifier output voltage and the rectifier current is a rectifier output current. [12] Method according to claim 10, wherein the one or more coefficients corresponding to the wireless baseline power transfer between the wireless power transmitter and the wireless power receiver are derived by: Performing a regression analysis on the received multitude of data on the received power and the corresponding rectifier voltages and rectifier currents of another wireless power receiver associated with the other wireless power transmission, and the determined multitude of measured power loss values ​​derived therefrom, in order to calculate the one or more coefficients. [13] Method according to claim 12, further comprising receiving one or more power loss scaling factors from the wireless power receiver, wherein the calculation of the friendly metal power loss is based on the one or more power loss scaling factors, wherein the one or more power loss scaling factors are based on the pairing between a wireless reference power transmitter or wireless power receiver and an actual wireless power transmitter or wireless power receiver. [14] Method according to claim 10, further comprising receiving one or more power loss scaling factors from the wireless power receiver, wherein the calculation of the friendly metal power loss is based on the one or more power loss scaling factors, wherein the one or more power loss scaling factors are based on the pairing between a wireless reference power transmitter or wireless power receiver and an actual wireless power transmitter or wireless power receiver.

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