RU2792026C2 - Wireless energy transmission - Google Patents

Abstract

FIELD: electrical engineering.

SUBSTANCE: invention relates to the field of electrical engineering, in particular to wireless energy transmission. Energy transmitter (101) transmits energy to energy receiver (105) by means of an electromagnetic energy transmission signal. Energy transmitter (101) contains output circuit (302, 103) with transmitting coil (103) generating an energy transmission signal in response to an excitation signal generated with exciter (301). Configuration controller (303) switches between energy transmission configurations having different maximum limit values of power and voltage amplitude for the excitation signal. Transmitter (307) transmits to energy receiver (105) a power configuration message containing data indicating voltage amplitude for the first energy transmission configuration, while receiver (305) receives a message with a request for changing energy transmission configuration from energy receiver (105). Specified configuration controller (303) switches energy transmitter (101) to the first energy transmission configuration in response to the specified message with the request for changing energy transmission configuration.

EFFECT: provision of different maximum limit values of power due to combined change in configuration of a transmitter and a receiver.

16 cl, 10 dwg

Description

FIELD OF TECHNOLOGY

The present invention relates to the operation of a wireless power transmission system, and in particular, but without exception, to approaches for supporting higher power levels in a wireless power transmission system such as a Qi system.

BACKGROUND OF THE INVENTION

For power from an external power source for most modern electrical products, it is necessary to provide a special electrical contact. However, this is generally impractical and requires the user to physically insert connectors or otherwise make physical electrical contact. Also, power requirements tend to vary considerably, and nowadays most devices come with their own dedicated power supplies, leaving the typical user with a large number of different power supplies, with each power supply specifically designed for a particular device. While the use of internal batteries may avoid the need for a wired connection to the power source during use, the use of batteries is only a partial solution as the batteries will need to be recharged (or replaced). The use of batteries can also lead to a significant increase in weight and a potential increase in the cost and size of devices.

In order to greatly improve usability, it has been proposed to use a wireless power supply in which energy is transferred by induction from a transmitter coil in a power transmitter device to a receiver coil in separate devices.

Power transfer by magnetic induction is a well known concept, mainly applied in transformers having a strong coupling between the primary inductance/transmitter coil and the secondary receiver coil. By separating the primary transmitter coil and the secondary receiver coil, wireless power transmission between the two devices is possible based on the principle of a loosely coupled transformer.

This arrangement allows power to be transferred wirelessly to the device without the need for any wires or physical electrical connections. In fact, this may allow you to simply place the device near or on top of the transmitter coil to recharge or receive power from an external source. For example, power transmitter devices can be made with a horizontal surface on which the device can simply be placed to receive power.

In addition, such wireless power transmission devices can preferably be configured such that the power transmitter device can be used with a variety of power receiver devices. In particular, an approach based on wireless power transmission, known as the Qi specification, has been defined and is currently under further development. This approach allows the use of Qi-compliant power transmitter devices with also Qi-compliant power receiver devices that do not have to be made by the same manufacturer or specifically designed for each other. The Qi standard also includes some functionality that allows you to tailor the operation for a specific power sink device (eg, depending on a specific power consumption).

The Qi specification is developed by the Wireless Power Consortium, at the website: http://www.wirelesspowerconsortium.com/index.htm l which has more information, in particular some specification documents.

The Qi specification in its original version 1.0 defined low power wireless power transmission, which in practice was limited to low power levels below 5W. Later versions extended this to higher power levels, and version 1.2, for example, provides for compliance testing at power levels up to 15W.

However, it is desirable to support even higher power levels, and in some cases, specialized designs have been introduced to achieve this. However, most of the proposed approaches to support high power wireless power transmission are generally sub-optimal and a number of problems or undesirable effects may occur. For example, supporting a large power range is a challenge. For example, large range variations in power delivered can be difficult to control just by adjusting or limiting the current supplied to the power transmitter coil. Another problem is to ensure that the effects of changing operating parameters and conditions, such as changing power levels, are tolerable and, for example, can be handled by the power receiver. For example, a significant and rapid change in the drive voltage can cause a transient voltage to be induced in the power receiver, thereby potentially causing an overvoltage (or undervoltage) situation.

Therefore, an improved approach to wireless power transmission is preferable, in particular, it is preferable to use an approach that can increase flexibility, reduce cost, reduce complexity, improve support for large power ranges, improve power transient response, improve adaptability and backward compatibility, improve power transmission operation. and/or improve performance.

DISCLOSURE OF THE INVENTION

Accordingly, it is a preferred object of the present invention to reduce, alleviate or eliminate one or more of the above disadvantages, alone or in any combination thereof.

In accordance with one aspect of the present invention, there is provided a power transmitter for wirelessly supplying power to a power receiver via an electromagnetic power transmission signal; the power transmitter includes: a transmitter coil for generating a power transmission signal in response to an excitation signal applied to the transmitter coil; an exciter for generating an excitation signal; a configuration controller for switching between the set of power transmission configurations, wherein the power transmission patterns of the set of power transmission configurations have different combinations of maximum power limit and voltage amplitude for the drive signal; a transmitter for transmitting a power configuration message to a power receiver, the power configuration message including data indicative of a voltage amplitude for a first power transmission pattern of the set of power transmission patterns; a receiver for receiving, from the power receiver, a request message to change the power transmission configuration; wherein the configuration controller is configured to switch the power transmitter to the first power transmission configuration in response to a request message to change the power transmission configuration.

The present invention may provide improved performance and/or improved power transfer in various scenarios. It may, in various embodiments, provide improved and more efficient power transfer over a wide range of power levels. This approach may, in various implementations, support, enable, enhance, or facilitate high power wireless power transmission.

In various embodiments, improved switching between different power transmission configurations can be achieved, and in particular, the effects of transient conditions and changes in power transmission parameters can often be mitigated. In particular, improved under/over voltage transient performance can be achieved in various implementations and scenarios.

Said set of power transfer patterns may have different combinations of maximum power limit and voltage amplitude for the drive signal in the sense that at least one of the maximum power limit and voltage amplitude is different for different power transfer patterns of the set of power transfer patterns.

The first power transfer configuration is a potential power transfer configuration. The first power transmission configuration is different from the current power transmission configuration (which is the power transmission configuration in which the power transmitter is currently operating).

Said configuration controller may be configured to switch the power transmitter from the current power transmission configuration to the first power transmission configuration in response to a request message to change the power transmission configuration. Said configuration controller may be configured to switch the power transmitter to the first power transmission configuration in response to receiving a request message to change the power transmission configuration. Said power transfer configuration change request message may request changing the current power transfer mode to the first power transfer mode.

The output circuit may or may consist of an oscillating (or storage) circuit containing a transmitter coil. The transmitter coil may be the resonating component of an oscillatory circuit. The oscillatory circuit may be a series oscillatory circuit or a parallel oscillatory circuit. The oscillatory circuit may contain one or more capacitors.

The voltage amplitude may be, for example, a voltage peak-to-peak amplitude, a peak amplitude, and/or a half-amplitude. In some implementations and for some signals, the voltage amplitude may be, for example, effective or RMS amplitude.

The voltage amplitude for the power transfer configuration may be a constant voltage amplitude for the drive signal. The power transmitter may be configured to control the power level of the power transmission signal by changing at least one of the frequency, duty cycle, and current amplitude of the drive signal. The voltage amplitude may be constant/fixed for a given power transfer configuration.

In some embodiments, the voltage amplitude for the power transfer configuration may be a range of voltage amplitudes for the drive signal. For example, the voltage amplitude for each power transfer configuration may be a maximum voltage amplitude limit and/or a minimum voltage amplitude limit. In some embodiments, the voltage amplitude for the first power transfer configuration presented in the power configuration message may be an indication of a voltage amplitude range and/or a maximum/minimum voltage amplitude limit for the first power transfer configuration. In some embodiments, the voltage amplitude for the first power transfer configuration presented in the power configuration message may be an indication of the nominal or initial voltage amplitude for the drive signal after switching to the first power transfer configuration.

According to a further feature of the present invention, the data indicates the relative difference between the voltage amplitude for the first power transfer configuration and the voltage amplitude for the current power transfer configuration.

This may provide higher efficiency in various implementations. This may provide a more efficient trade-off between accuracy and communication channel bandwidth in various implementations, and may provide particularly important information for transient responses as power transmission configurations change.

According to a further feature of the present invention, the data indicates the relationship between the voltage amplitude for the first power transfer configuration and the voltage amplitude for the current power transfer configuration.

This may provide higher efficiency in various implementations. This may allow a more efficient trade-off between accuracy and communication channel bandwidth in various implementations, and may provide particularly important information for transient responses as power transmission configurations change.

According to a further feature of the present invention, the first power transmission configuration is a power transmission configuration of a set of power transmission configurations having a maximum power limit that is at least one of the next higher maximum power limit and the next lower maximum power limit for the maximum power limit of the current power transfer configuration.

This may provide particularly efficient operation in various implementations. This may in particular provide an efficient approach for dynamic power level control that can support a wide range of power levels while still maintaining low communication requirements. This can limit power level changes to reduce transient properties and/or reduce communication requirements, for example by ensuring that no additional information other than voltage amplitude is required for potential power transfer patterns.

According to a further feature of the present invention, the power configuration message comprises data indicating a voltage amplitude for a second power transmission pattern of said power transmission pattern set, wherein the first power transmission pattern is a power transmission pattern of said power transmission pattern set having a maximum limit a power value representing the next higher maximum power limit value for the maximum power limit value in the current power transmission configuration, and the second power transmission configuration is a power transmission configuration of the specified set of power transmission configurations having a maximum power limit value which is the next higher low maximum power limit for the maximum power limit in the current power transfer configuration.

This may provide particularly efficient operation in various implementations. The power mode message may specifically provide information for the closest (in terms of maximum power limit) power transmission configurations available to the power transmitter to increase and decrease the power level accordingly.

According to a further feature of the present invention, the set value of the voltage amplitude indicating data indicates that the set of power transmission patterns does not contain a power transmission pattern that has a higher maximum power limit value than the maximum power limit value of the current power transmission pattern.

This can provide a particularly efficient communication of the presence of power transmission configurations.

In some embodiments, the set value of data indicating voltage amplitude indicates that the set of power transfer configurations does not contain a power transfer configuration that has a lower maximum power limit than the maximum power limit of the current power transfer configuration.

This can provide a particularly efficient communication of the presence of power transmission configurations.

In some embodiments, the setpoint data value indicating the voltage amplitude indicates no change in the voltage amplitude in the first power transfer configuration relative to the voltage amplitude in the current power transfer configuration.

In accordance with a further feature of the present invention, the configuration controller is configured to transmit a power configuration message in response to detecting that the power transfer performance meets a criterion.

This may provide particularly advantageous performance and operation in many embodiments. This approach can support power transmitter-initiated power transfer reconfiguration while ensuring that this is done in conjunction with the power receiver, thereby reducing the risk of unwanted effects at the power receiver.

The power transfer performance may in particular be a parameter indicating the current power level of the power transfer signal (for the current power transfer configuration), such as, for example, a parameter indicating the frequency or current of the drive signal.

In accordance with a further feature of the present invention, the configuration controller is configured to transmit a power configuration message in response to detecting that the current power level of the power transmitter exceeds a threshold, said threshold being dependent on the maximum power limit of the current power transmission configuration.

This may provide particularly advantageous performance and operation in many embodiments. This approach can support power transmitter-initiated power transfer reconfiguration while ensuring that this is done in conjunction with the power receiver, thereby reducing the risk of unwanted effects at the power receiver.

In accordance with a further feature of the present invention, the configuration controller is configured to transmit a power configuration message in response to receiving a power configuration information request message from a power receiver.

This may provide particularly advantageous performance and operation in many embodiments. This approach can support a power receiver-initiated reconfiguration of the power transmission while ensuring that this is done in conjunction with the power transmitter.

According to a further feature of the present invention, the configuration controller is configured to switch the power transmitter to a first power transmission configuration after transmitting an acknowledgment message to the power receiver, said acknowledgment message acknowledging receipt of the request message received from the power receiver.

This may provide particularly advantageous performance and operation in many embodiments.

In accordance with one aspect of the present invention, there is provided a power receiver for wirelessly receiving power from a power transmitter via an electromagnetic power transmission signal, comprising: an input circuit comprising a power receiver coil configured to extract power from the power transmission signal; a receiver for receiving a power configuration message from a power transmitter, said power configuration message comprising data indicating a drive signal voltage amplitude for at least a first power transmission configuration from a set of power transmission configurations, said power transmission configurations from said set of transmission configurations energies have various combinations of maximum power limit and voltage amplitude, and wherein said drive signal is for a power transmitter output circuit comprising a transmitter coil to generate a power transfer signal in response to a drive signal applied to the output circuit; a configuration controller configured to detect a preference for changing the power transmission configuration to switch the power transmitter to the first power transmission configuration; and a transmitter for transmitting a power transmission configuration change request message to the power transmitter in response to detecting a power transmission configuration change preference, said power transmission configuration change request message comprising a request to switch the power transmitter to the first power transmission configuration.

In accordance with a further feature of the present invention, the configuration controller is configured to control the power transmission to change the voltage induced in the power receiver coil before changing the power transmission configuration to the first power transmission configuration.

This may provide particularly advantageous performance and performance in various implementations. This can, in various scenarios, compensate or mitigate transient voltage fluctuations and, for example, prevent undervoltage or overvoltage conditions.

In accordance with a further feature of the present invention, the configuration controller is configured to change the load impedance for the power receiver coil before changing the power transfer configuration to the first power transfer configuration.

This may provide particularly advantageous performance and performance in various implementations.

In accordance with one aspect of the present invention, there is provided a method of operating a power transmitter that wirelessly transmits power to a power receiver via an electromagnetic power transfer signal, comprising: generating a power transfer signal via a transmitter coil in response to a drive signal applied to the transmitter coil; generating an excitation signal; switching between a set of power transmission configurations, wherein said power transmission patterns of said set of power transmission configurations have different combinations of maximum power limit and voltage amplitude for the drive signal; transmitting to the power receiver a power configuration message containing data indicative of a voltage amplitude for a first power transmission configuration of said set of power transmission configurations; receiving a power transfer configuration change request message from the power receiver; and wherein switching between said set of power transmission configurations switches the power transmitter to the first power transmission configuration in response to the power transmission configuration change request message.

In accordance with one aspect of the present invention, there is provided a method for operating a power receiver receiving power wirelessly from a power transmitter via a power transmission electromagnetic signal, comprising: extracting power via a power receiver coil from the power transmission signal; receiving from the power transmitter a power configuration message comprising data indicating a voltage amplitude of the drive signal for at least a first power transmission configuration of a set of power transmission configurations, said power transmission patterns of said set of power transmission configurations having different combinations of maximum power limit value and a voltage amplitude, wherein said drive signal is provided to an output circuit of a power transmitter comprising a transmitter coil to generate a power transfer signal in response to a drive signal supplied to the output circuit; detecting a power transmission configuration change preference for switching the power transmitter to the first power transmission configuration; and transmitting to the power transmitter a power transmission configuration change request message in response to detecting a power transmission configuration change preference, said power transmission configuration change request message comprising a request to switch the power transmitter to the first power transmission configuration.

In accordance with yet another aspect of the present invention, a wireless power transmission system is provided for wirelessly supplying power to a power receiver from a power transmitter via an electromagnetic power transmission signal; wherein the power transmitter comprises: an output circuit comprising a transmitter coil for generating a power transmission signal in response to a drive signal applied to the output circuit; a driver for generating an excitation signal; a configuration controller for switching between a set of power transfer configurations, said power transfer patterns of said set of power transfer configurations comprising various combinations of a maximum power limit and a voltage amplitude for the drive signal; a transmitter for transmitting a power configuration message to a power receiver, said power configuration message comprising data indicative of a voltage amplitude for a first power transmission pattern of said set of power transmission patterns; a receiver for receiving, from the power receiver, a request message to change the power transmission configuration; and wherein the configuration controller is configured to switch the power transmitter to the first power transmission configuration in response to said power transmission configuration change request message; and a power receiver, comprising: an input circuit containing a power receiver coil configured to extract power from the power transmission signal; a receiver for receiving a power configuration message from the power transmitter, a configuration controller configured to detect a preference for changing the power transmission configuration to switch the power transmitter to the first power transmission configuration; and a transmitter for transmitting a power transmission configuration change request message to the power transmitter in response to detecting the power transmission configuration change preference, said power transmission configuration change request message comprising a request to switch the power transmitter to the first power transmission configuration.

These and other aspects, features, and advantages of the present invention will become apparent and will be explained with reference to the embodiment(s) described below.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will be described solely by way of example with reference to the drawings, in which:

FIG. 1 shows an example of elements of a power transmission system in accordance with some embodiments of the present invention;

FIG. 2 shows an example set of power transfer configurations for a power transmitter in accordance with some embodiments of the present invention;

FIG. 3 shows an example of elements of a power transmitter in accordance with some embodiments of the present invention;

FIG. 4 shows an example of the elements of the output stage of the energy transmitter;

FIG. 5 shows an example of the elements of the output stage of the energy transmitter;

FIG. 6 shows an example of elements of a power receiver in accordance with some embodiments of the present invention;

FIG. 7 is an example of a power configuration message in accordance with some embodiments of the present invention;

FIG. 8 shows an example of a power transfer configuration change request message in accordance with some embodiments of the present invention;

FIG. 9 shows an example of messaging in accordance with some embodiments of the present invention; And

FIG. 10 shows an example of messaging in accordance with some embodiments of the present invention.

IMPLEMENTATION OF THE INVENTION

The following description focuses on embodiments of the present invention that can be applied to a system for wireless power transmission, and which involve the use of a power transmission approach such as known from the Qi specification. However, it should be understood that the present invention is not limited to this application, but can be applied to many other wireless power transmission systems.

FIG. 1 shows an example of a power transmission system in accordance with some embodiments of the present invention. Said power transmission system comprises a power transmitter 101 which contains (or is connected to) a transmitter coil/inductance 103 . The system also includes a power receiver 105 which contains (or is connected to) a receiver coil/inductance 107 .

The system provides an electromagnetic power transfer signal that can inductively transfer power from the power transmitter 101 to the power receiver 105 . In particular, the energy transmitter 101 generates an electromagnetic signal that is propagated as a magnetic flux by the transmitter coil or inductance 103 (which is typically part of the output circuit in the form of an oscillating or storage circuit). The power transfer signal may correspond to an electromagnetic power transfer component representing the transfer of power from the power transmitter to the power receiver, and may be considered a corresponding component of the generated electromagnetic field that transfers power from the power transmitter to the power receiver. For example, if there is no load on the receiver coil 107, no energy will be extracted by the power receiver from the generated electromagnetic field (except for losses). In such a case, when the transmitter coil 103 is energized, an electromagnetic field with a potentially high field strength can be generated, but the power level of the power transmission signal will be zero (not including losses). In some situations, if a foreign object is present, the power transfer signal can be considered as including a component corresponding to the power transfer of the foreign object, and thus the power transfer signal can be considered as corresponding to the energy received from the electromagnetic field generated by the power transmitter.

The power transfer signal can typically have a frequency from about 20 kHz to about 500 kHz, and often for Qi-compatible systems, typically in the range of 95 kHz to 205 kHz (or, for example, for high power kitchen applications the frequency may, for example, typically be in the range of 20 kHz to 80 kHz). The transmitter coil 103 and the power receiving coil 107 are loosely coupled, and thus the power receiving coil 107 receives a power transmission signal (at least a portion of the signal) from the power transmitter 101 . Thus, power is transmitted from the power transmitter 101 to the power receiver 105 via wireless inductive coupling from the transmitter coil 103 to the power receiving coil 107. The term "power transfer signal" is mainly used to refer to an inductive signal/magnetic field between the transmitter coil 103 and the power receiving coil (magnetic flux signal) 107 .

In this example, the power receiver 105 is specifically a power receiver that receives power with the receiver coil 107 . However, in other embodiments, power receiver 105 may include a metal element, such as a metal heating element, in which case the power transfer signal directly induces eddy currents resulting in direct heating of said element.

The system is capable of transmitting significant power levels, and in particular, the power transmitter is capable of delivering power levels in excess of 500 mW, 1 W, 5 W, 50 W, 100 W, or 500 W, in various implementations. For example, for Qi applications, power transfers can typically range from 1-5W for low power appliances (basic power profile) up to 15W for Qi specification version 1.2, up to 100W for higher power electrical appliances such as power tools, laptops, drones, robots, etc., and over 100W to over 1000W for very high power electrical appliances such as kitchen appliances.

The operation of the energy transmitter 101 and the energy receiver 105 will now be described with specific reference to an implementation that generally conforms to the Qi specification (except as described herein or (logically) modifications and improvements) or is suitable for the specification of more powerful kitchen appliances being developed by the Consortium wireless energy. In particular, the power transmitter 101 and the power receiver 105 may conform to or be compatible with the Qi specification version 1.0, 1.1, or 1.2 (except as described herein or (logically) modifications and improvements).

The system of FIG. 1 is designed to support power transmission with a wide range of power levels. This system supports this by allowing the power transmitter to operate in a variety of different power transmission configurations with configurations corresponding to different power levels.

In particular, some power transmission configurations use different voltage amplitudes to drive the output circuit with the transmitter coil 103. Typically, the output circuit is a series tank circuit, wherein the transmitter coil forms an inductive resonant component, and said series tank circuit is driven by a constant voltage amplitude excitation signal, and the power level is determined and varied by varying the current supplied to the output circuit, either directly or indirectly. , for example, by changing the drive frequency or duty cycle of the drive signal. However, large changes in power level become difficult to maintain in this manner, since the required current changes become difficult to achieve and control. Accordingly, the system of FIG. 1 allows the power transmitter 101 to switch between different power transmission configurations, which may correspond to different maximum power limits, and use different voltage amplitudes for the drive signal applied to the transmitter coil 103. In particular, for a given power transfer configuration, the voltage amplitude of the drive signal may be constant, but for different power transfer configurations, said voltage amplitude may differ. The indicated maximum power limit may be an upper power limit of the power transmission signal that is supported in the current power transmission configuration. This power limit can be imposed by limiting the current of the drive signal supplied to the transmitter coil 103 . Thus, the maximum power limit can correspond to the maximum current limit.

The voltage amplitude may be peak-to-peak amplitude, peak amplitude, or half-amplitude for the drive signal, and the drive signal in various embodiments of the invention may be a square wave or a square wave. In particular, the drive signal may be a signal that has a value of either +Va or -Va or 0, where Va is the (peak) voltage amplitude. The drive signal may have a mean value of 0. In some implementations, the drive signal may be a different waveform such as, for example, a sine wave, a triangular wave, and the like.

Thus, the power transmitter 101 can be configured to operate in one of a variety of power transfer configurations, in which each power transfer configuration specifically can correspond to a different combination of drive signal voltage amplitude and maximum power limit (and therefore maximum current limit) . For example, as shown in FIG. 2, power transmitter 101 may be configured to operate in one of n different power transmission configurations, each configuration having a corresponding maximum power limit and a fixed voltage amplitude drive signal. For example, the power transmitter 101 may be configured to select the current power transfer configuration from a set of power transfer configurations having the following maximum power limits/maximum current and voltage amplitude limits of the control signal (example shows effective voltage amplitude and maximum current limit ).

• 5 V, 1.5 A (7.5 W)

• 9 V, 1 A (9 W)

• 5 V, 2 A (10 W)

• 12 V, 1 A (12 W)

• 9 V, 2 A (18 W)

• 12 V, 1.5 A (18 W)

• 19 V, 1 A (19 W)

• 12 V, 2 A (24 W)

• 19 V, 2 A (38 W)

• 19 V, 3 A (57 W)

Thus, the power transmitter 101 may be configured to operate in one of a variety of power transmission configurations with different voltage amplitudes, in which higher voltage amplitudes are needed to achieve higher power levels.

FIG. 3 shows the elements of the energy transmitter 101 shown in FIG. 1 in more detail.

The power transmitter 101 includes a driver 301 that is configured to generate a drive signal applied to an output circuit, which in this example is an oscillatory circuit formed by a transmitter coil 103 and a transmitter capacitor 302. The transmitter coil 103, in response to being energized by the drive signal, generates an electromagnetic field, and thus an electromagnetic power transfer signal, which enables power to be transferred to the power receiver 105. The power transfer signal is provided (at least) during the power transfer phase.

Driver 301 is typically an inverter drive circuit that generates an alternating signal from a DC voltage. The output of the driver 301 is usually a switching bridge, generating a drive signal by appropriately switching the switches of the switching bridge. FIG. 4 shows a half-bridge switching bridge/inverter. The switches S1 and S2 are controlled in such a way that they are never closed at the same time. Alternately, switch S1 is closed when switch S2 is open and S2 is closed when S1 is open. These keys open and close at the required frequency, thereby generating an alternating signal at the output. Typically, the inverter output is connected to the transmitter inductor via a resonant capacitor. FIG. 5 shows a full bridge switching bridge/inverter. The switches S1 and S2 are controlled in such a way that they are never closed at the same time. The switches S3 and S4 are controlled in such a way that they are never closed at the same time. Switches S1 and S4 are alternately closed while switches S2 and S3 are open, and then switches S2 and S3 are closed while switches S1 and S4 are open, thereby creating a square wave output. The keys open and close at the required frequency.

Thus, the driver 301 generates a drive signal for the output tank circuit and thus for the transmitter coil 103. The drive signal has a (substantially) constant voltage amplitude for a given power transfer configuration. In this example, a constant voltage amplitude is achieved by setting a constant voltage on the power rail of the exciter output circuit, i.e. voltage V on the power rail of the bridges shown in FIG. 4 and 5 are constant for a given power transfer configuration. Switching via bridge transistors respectively switches the output voltage between 0 and V for a half bridge and between V and -V for a full bridge. Thus, in this example, the power transmitter can set the power rail voltage to be constant for any given power transfer configuration, but subject to change depending on the power transfer configuration.

The power transmitter 101 also includes a power transmitter controller 303 configured to control the operation of the power transmitter 101 in accordance with desired operating principles. In particular, the power transmitter 101 may contain a variety of functionalities required to implement power control in accordance with the Qi specifications.

The power transmitter controller 303 is particularly configured to control the generation of the drive signal by the driver 301. The power transmitter controller 303 is particularly capable of setting the driver power rail voltage appropriate to the particular power transfer configuration in which the power transmitter is currently operating.

The power transmitter controller 303 can also dynamically control the power level of the drive signal, and thus the power transfer signal, generated by the transmitter coil 103. The power transmitter controller 303 specifically includes a power loop controller controlling the power level of the power transmission signal in response to power control messages received from the power receiver 105 during the power control phase. Power level control, in particular, can be achieved by controlling the current of the drive signal or, more typically, by controlling the duty cycle or frequency of the drive signal. In the latter example, the power level can be increased by shifting the frequency closer to the resonant frequency of the output tank circuit containing the transmitter coil 103 (and/or the resonant frequency of the power receiver tank circuit 105 that contains the receiver coil 107) and reduced by shifting the frequency further away from the resonant frequency. frequencies.

In addition, the power transmitter controller 303 for a given power transmission configuration may limit the power level to the maximum power level. This is usually done by limiting the drive signal current. The current may be actively limited, or in some implementations the maximum power limit may be set in an indirect (potentially even unintentional) manner and, for example, by practically limiting the current that can be supplied to the exciter by the power supply. In some implementations, the maximum power limit may be limited by the control algorithm, for example, to prevent the thermal characteristics of the switching bridge transistors from being exceeded. For example, for a system in which the power level is controlled by controlling the frequency and/or duty cycle of the drive signal/power transmission signal, the controller can continuously monitor the power level and adjust the frequency according to the requirement that the power level should not exceed the maximum power limit. for the current power transfer configuration.

To receive data and messages from energy receiver 105, energy transmitter 101 includes a first receiver 305 that is configured to receive data and messages from energy receiver 105 (one skilled in the art will appreciate that a data message may comprise one or more bits of information). In this example, the power receiver 105 is configured to load modulate the power transmission signal generated by the transmitter coil 103, and the first communication device 305 is configured to detect changes in voltage and/or current in the transmitter coil 103 and, based on them, demodulate the modulation imposed by the load. The person skilled in the art is familiar with the principles of load modulation, such as those used in Qi wireless power transmission systems, so they will not be described in more detail.

The power transmitter 101 is also configured to transmit data to the power receiver 105 and accordingly comprises a first transmitter 307 which is configured to transmit data to the power receiver, for example by specifically modulating the drive signal and thus the power transfer signal using frequency, amplitude and/or phase modulation.

It should be understood that in other implementations, other approaches may be used to transfer data between the transmitter 101 energy and the receiver 105 energy. For example, in some embodiments, communication may be performed using a separate communication channel, which may be achieved using a separate communication coil, or actually using the transmitter coil 103. For example, in some embodiments, short-range contactless communication may be implemented, or a high frequency carrier (eg, 13.56 MHz) may be superimposed on the power transfer signal.

The power transmitter 101 also includes a first configuration controller 309 that is configured to control the power transmission configuration in which the power transmitter 101 operates, and thus specifically configured to switch the power transmitter 101 between different power transmission configurations from a set of possible power transmission configurations. .

FIG. 6 shows some exemplary elements of the energy receiver 105.

The receiver coil 107 is connected to a power receiver controller 601 which connects the receiver coil 107 to the load 603. The power receiver controller 601 includes a power control path that converts the power received by the receiver coil 107 into a signal suitable for supply to the load. In addition, the power receiver controller 601 may contain various functionality of the power receiver controller required for performing power transmission, and in particular, functions required for performing power transmission in accordance with Qi specifications.

The energy receiver 105 further comprises a second receiver 605 that is configured to receive data transmitted by the energy transmitter 101. In this example, the second receiver 605 is configured to demodulate the amplitude, frequency, and/or phase modulation of the power transmission signal to extract the data transmitted by the power transmitter.

To support communication of the power receiver 105 with the power transmitter 101, the power receiver 105 includes a second transmitter 607. The second transmitter 607 is configured to transmit data to the power transmitter by varying the loading of the receiver coil 107 in response to the incoming data to be transmitted to the power transmitter 101. The load changes are then detected and demodulated by the energy transmitter 101 in a manner known to those skilled in the art.

As noted above, in other implementations, other communication methods may be used, for example, a separate and dedicated near field communication channel, such as NFC, may be used.

The power receiver 105 further comprises a second configuration controller 609 configured to support the use of various power transmission configurations, and in particular, it can support switching of the power transmitter 101 between and control different power transmission configurations.

Thus, in the system of FIG. 1, a number of different power transmission configurations with different maximum power levels can be used for power transmission, thereby providing a potentially wide range of supported power levels, including quite high power levels. In addition, the power transmitter and power receiver may be configured to dynamically switch between different power transmission configurations. For example, the power transfer operation may initially start at a low power level and then gradually increase the power level to a higher level. For example, charging a high-capacity battery for safety purposes may start at lower charge levels and then increase to a potentially high level with high charging current when safety support is provided (eg, ensuring there are no foreign metal objects nearby). Similarly, in various implementations, the load 603 may be a varying load that has a highly variable power consumption. For example, the load may be a device containing a motor running exclusively intermittently. Thus, in a variety of situations, it may be desirable to change between different power transmission configurations, such changes being potentially unpredictable in both the power up direction and the power down direction.

However, while this may provide performance improvements over a wider power range in various implementations, it is also understood that there are potential risks and difficulties in switching between different power transfer configurations with different drive voltages for the drive signal.

In particular, a change in the drive signal voltage may result in a step/transient change in the induced voltage across the receiver coil 107. Thus, switching from one power transmission configuration to another can result in undervoltage or overvoltage in the power receiver. For some power receivers and in some situations, such an undervoltage or overvoltage condition may be completely acceptable and may not have any significant effect on operation. However, for other power receivers and/or other scenarios, undervoltage and/or overvoltage can have a significant impact and may result in suboptimal or even incorrect operation. Indeed, in some situations it can even be foreseen that damage to the power receiver may result from overvoltage if appropriate precautions are not taken.

As a specific example, the power transmitter may operate in a 10W (5V, 2A) configuration, with the power receiver controlling its operating mode to 8V, 1A. When the power transmitter switches to the next higher configuration, such as 12W (12V, 1A), the power receiver will detect 12/5*8 = 19.5V, 2.4A from the start, which is far beyond the capability of the power transmitter in this configuration. Accordingly, power transmission may be interrupted due to the generated overvoltage or overpower condition.

A similar situation can occur when switching to a reduced power configuration. For example, if the power transmitter is operating in a 12V, 1A configuration and the power receiver only accepts 4W (5V, 0.8A for example), it may be preferable to switch the power transmitter to the next level configuration, such as 5V. 1.5 A. If this switching is done without preparing the power receiver, it will detect a voltage of 5/12*5 = 2.1 V after switching, which may be too low to support its operation (i.e. at undervoltage). Accordingly, this will also lead to the termination of energy transmission.

According to the approach shown in FIG. 1, a specific approach to switching between power transmission configurations is implemented that may provide improved performance in various implementations. This approach allows the power transmitter and power receiver to cooperate to more precisely control the switching of the power transmission configuration and, in particular, to ensure that the power receiver is ready to switch from one power transmission configuration to another and usually completely controls this switching, thereby preventing the occurrence of unforeseen under or over voltage conditions.

This approach is based on the exchange of information between the power transmitter and the power receiver to manage and coordinate changes in the power transmission configuration. The exchange of messages, in particular, may allow the power receiver to manage a change in the power transfer configuration for the power transmitter, so that this exchange can be provided without a change that leads to unacceptable effects on the power receiver (for example, it can allow the power receiver to compensate for these effects).

Thus, in this example, the power transmitter 101 comprises a first configuration controller 309 configured to control the power transmitter 101 to operate in a power transfer configuration selected from a plurality of power transfer configurations, each of which may be a different combination of (substantially) constant the voltage amplitude of the drive signal for the output circuit containing the transmitter coil 103, and the maximum power limit of the power transmission signal/drive signal. In addition, the power transmitter 101 is configured to transmit a power configuration message to the power receiver 105, which contains data indicative of a voltage amplitude for the drive signal for one or more power transmission patterns of the set of power transmission patterns.

The power configuration message, in particular, may contain data describing the voltage amplitude for the power transmission configuration for one or more possible power transmission configurations that the power transmitter 101 can potentially switch to. In various implementations, the power configuration message may specifically provide voltage amplitude information for the next higher and/or next lower power transfer configuration in a given (e.g., predetermined or previously reported) sequence of power transfer patterns in which the transmitter 101 energy. For example, said power transfer patterns may be ordered in order of maximum power limit (and in order of voltage amplitude in case some power transfer patterns have the same maximum power limit), and the power configuration message may indicate the value of the next higher and lower power transfer configuration according to this sequence. The power configuration message can accordingly provide a voltage amplitude for an immediately higher maximum power limit and an immediately lower maximum power limit.

The voltage indication may be given as an absolute value or, for example, as a relative value relative to the voltage amplitude of the current power transfer configuration.

In this approach, the power receiver 105 can accordingly be provided with information about the power transmission configurations into which the power transmitter can switch.

The second receiver 605 of said power receiver 105 may receive a power configuration message, and the power receiver 105 accordingly may be informed of potential changes in the power transfer configuration and resulting changes in voltage amplitude. Accordingly, said power receiver has information that allows it to evaluate the result of a subsequent change in the power transmission configuration.

In addition, the power receiver 105 includes a second configuration controller 609 that is configured to detect a power transmission configuration preference for switching the power transmitter to the power transmission configuration (one of the configurations) indicated in the power configuration message.

The desire/request/preference to change the power transmission configuration can be detected in any suitable manner and using any suitable algorithm/criteria. This algorithm/criteria does not depend on any particular approach or requirement, or even on where the indicated preference is determined, by what function, or even by what device or apparatus. Thus, this approach is based on the detection by the second configuration controller 609 that there is a preference for changing the power transfer configuration, but does not depend on where, why or how the preference occurs.

In various implementations, this preference may be determined at the power receiver 105, in particular, the second configuration controller 609. For example, the second configuration controller 609 may determine that the power transfer is close to the maximum power limit for the current power transfer configuration and that in power increase and hence preference is given to switching to a power transmission configuration with a higher maximum power limit.

In some implementations, a preference for switching to a different power transfer configuration may be determined, for example, by the power transmitter, and the second configuration controller 609 may detect this preference, for example, in response to a property of the power transfer signal or data transmission from the power transmitter. For example, the power transmitter may transmit a request to change the power transmission configuration to the power receiver when the power transmitter determines that such a switch is desired. Indeed, in various embodiments, the power transmitter may be configured to transmit a power configuration message in response to the power transmitter determining that there is a preference for changing the power transmission configuration, and therefore the power configuration message itself may be a message with a request to change the power transmission configuration.

The second transmitter 607 may be configured to transmit a power transfer configuration change request message to the power transmitter in response to detecting a power transfer configuration change preference. In various embodiments, said transfer may be conditioned, for example, by a specially conditioned voltage amplitude for the corresponding power transfer configuration corresponding to certain criteria.

For example, the second configuration controller 609, in response to detecting a desire to change the power transfer configuration to a predetermined potential power transfer configuration, may evaluate whether changing that potential power transfer configuration would result in an unacceptable under or over voltage condition that could occur in the power receiver as a result of said switching. As a simple example, the second configuration controller 609 can simply determine if the ratio between the voltage amplitude of the current power transfer configuration and the voltage amplitude of the potential power transfer configuration exceeds some threshold that is considered acceptable for a particular power receiver (in particular circumstances). If so, the second transmitter 607 may proceed to transmit a power transmission configuration change request message to said power transmitter, otherwise no power transmission configuration change request message is transmitted.

In still other embodiments, the second transmitter 607 may be configured to always send a power transfer configuration change request message to the power transmitter 101 if a preference for changing the power transfer configuration is detected. In such implementations, power receiver 105 may be configured to adapt the operation or configuration of power receiver 105 in response to the voltage amplitude of the requested power transfer configuration, and generally in response to the relationship between the voltage amplitude of the requested power transfer configuration and the voltage amplitude of the current transmission configuration. energy.

For example, if the change in voltage amplitude is small enough, no undervoltage or overvoltage problem conditions will occur, and thus no operation or configuration changes will be required. However, if this change in voltage amplitude is large enough, it can lead to unacceptable transient response and, for example, transient overvoltage until the power control loop can adapt the power level, etc. In such a case, the operation of the power receiver 105 may be adapted by the second configuration controller 609 in preparation for changing the power transmission configuration. For example, the input circuit may be isolated from a sensitive circuit that may be susceptible to an overvoltage condition. In particular, load 603 may be disabled in various implementations.

The first receiver 305 may receive a power transfer configuration change request message from the power receiver 105, and in response, the first configuration controller 309 may proceed to switch the power transmitter 101 to the new power transfer configuration. In some embodiments, the power transfer configuration change request message may indicate the power transfer configuration, eg, indicate whether power transmitter 101 is requested to switch to a higher or lower maximum power limit. In still other embodiments, this may be implicit, for example, by having only one potential power transfer configuration.

Thus, in this system, the power transmission reconfiguration is not performed exclusively by the power transmitter 101, but is performed in cooperation between the power transmitter and the power receiver. The power receiver is not only informed of the possible effect of a power transmission configuration change, but also controls whether a power transmission configuration change occurs. Thus, a power transfer reconfiguration can in principle be initiated by a power transmitter or a power receiver, but this approach allows the power receiver to control whether or not a power transfer reconfiguration occurs.

Accordingly, this approach may allow for a flexible approach that can effectively support a wide range of power levels by using a range of different power transmission configurations with different voltages and maximum power limits. This approach can be used with a wide range of power transmitters and receivers without the risk of, for example, unacceptable overvoltage or undervoltage conditions. It can even be guaranteed that a given change in power transmission configuration only occurs in this manner, and only occurs if said change is acceptable to a particular power receiver. Thus, this approach may allow power transmission to be tailored to a particular power transmitter and corresponding power receiver.

This approach can also provide improved backwards compatibility and, for example, allow introduction into systems where some power receivers do not support different power transfer configurations. Such a power receiver would not include the functionality to generate and transmit a power transfer configuration change request message, and accordingly, the power transmitter would not switch the power transfer configuration, even if it would be beneficial for it to do so.

In some embodiments, the power configuration message may also include an indication of the maximum power level in said power transmission configuration(s) for which voltage indicator(s) is(are). For example, the power configuration message may explicitly indicate the maximum power level with dedicated data, such as by providing a value in watts or by providing a reference to one of a given set of levels.

However, in various implementations, the power configuration message may not contain any data defining the maximum power limit for the specified power transmission configuration(s). In some such implementations, the power configuration message itself may (implicitly) indicate some information about maximum power levels. For example, as noted above, the power configuration message may itself indicate whether a higher and/or lower maximum power limit exists. In some implementations, the maximum power limits for a specified set of power transfer configurations are predetermined and known to the power receiver (or, for example, communicated to the power receiver during power transfer initialization). In this case, the power receiver will be aware of the maximum power limit for the next higher and next lower power transmission configurations, and thus the power configuration message implicitly, by providing a voltage indication, also provides an indication of the maximum power limits.

In various implementations, the power configuration message, as specifically stated, may provide a voltage amplitude for a power transfer configuration that has a maximum power limit that is at least one of the next higher maximum power limit or the next lower maximum power limit. with respect to the maximum power limit in the current power transmission configuration, or in various implementations, it is preferred that said power transmission configuration which has the maximum power limit be at least one of the next higher maximum power limit and the next lower maximum power limit in relation to the specified maximum power limit in the current power transmission configuration (thus, the voltage amplitude can be foreseen deducted for both the next higher and next lower power transfer configurations).

Thus, in various implementations, said power configuration message may contain information about two power transfer patterns that correspond to the next lower and higher available power limit. This can provide an efficient system in which power levels can be changed flexibly while maintaining low complexity and low communication bandwidth. For example, new data only needs to be transmitted after a change in power transmission configuration, and data is only required for one or two power transmission configurations. In particular, communication is limited to a very small number of parameters and it is not necessary to transmit data for all power transmission configurations that are supported by the power transmitter. In practice, this is a significant advantage since communication between a power transmitter and a power receiver is very slow in wireless power transmission systems such as Qi systems.

This approach can also provide the ability to limit voltage step changes to small steps. For example, a large power level change is broken down into many smaller steps, resulting in smoother transients.

In this example, the power transmitter accordingly transmits to the power receiver information about the next higher voltage configuration or the next lower voltage configuration available from the set of power transmission configurations supported by said power transmitter. The power receiver may then request a switch to a lower or higher configuration. Because the power receiver needs more or less power, it can iterate over these configurations. This avoids changing the configuration of the power transmitter without warning, which can cause difficulties or even damage the power receiver.

In various embodiments, the voltage amplitude indication can advantageously be provided as a relative difference between the voltage amplitude for the potential power transfer configuration and the voltage amplitude for the current power transfer configuration, and in particular as a ratio between the two. This may be particularly advantageous in embodiments in which only contiguous power transfer patterns are specified, as this may help normalize the value to be transmitted, thereby providing a more accurate representation for a given number of bits. For example, if the maximum voltage amplitude step between adjacent power transfer patterns is a multiplier of, for example, 2, the indication of this ratio should only cover the range, for example, from 1 to 2, despite, for example, the specified set of power transfer patterns covering the amplitude range voltage, for example, up to a factor of 10.

An example of a possible power configuration message is shown in FIG. 7. In this example, the power configuration message is referred to as a Power Supply Configuration (PSC) packet, which is transmitted from a power transmitter to a power receiver. In this example, the PSC data packet contains two fields, each of which is 8 bits. The first field contains the voltage step down data value and the second field contains the voltage step up data value, wherein the first field indicates the relative change in drive signal voltage amplitude if the power transmitter switches to the next lower power transmission configuration, and the second field indicates the relative amplitude change excitation signal voltage if the power transmitter switches to the next higher power transfer configuration. As a specific example, these values may be provided according to the following protocol:

Voltage step down: The load voltage will decrease by 1/64 of this factor when the next lower power transfer configuration is activated (value in the range 64…255).

Voltage Step Up: Load voltage will increase by 1/64 of this factor when the next higher power transfer configuration is activated (value in the range 64…255).

In some implementations, a specified value of a specified data field containing data indicating the voltage amplitude for a potential power transfer configuration may be used to indicate that the current power transfer configuration is an extreme power transfer configuration in the sense that it is a power transfer configuration on highest or lowest power level.

Thus, a set value for the voltage amplitude data field in the power configuration message can be used to indicate to the power receiver that a given set of power transfer patterns supported by said power transmitter does not include any power transfer pattern having more than high maximum power limit. Similarly, the specified voltage amplitude data field in the power configuration message can be used to indicate to a power receiver that a given set of power transfer patterns supported by said power transmitter does not include any power transfer pattern having a higher maximum power limit.

For example, for the PSC of FIG. 7, a value of 0 in these fields may indicate that there is no next higher or lower configuration (i.e., a 0 in the Voltage Step Down field indicates no lower power transfer configuration, and a 0 in the Step Up voltage" indicates the absence of a higher power transfer configuration).

In some embodiments, the voltage amplitude indicative data setpoint indicates that there is no change in the voltage amplitude in the potential power transfer configuration relative to the voltage amplitude in the current power transfer configuration. For example, for communicating with the PSC of FIG. 7, a value of 64 may indicate that the voltage amplitude will not change (but the maximum power limit may change).

It is also understood that the power transfer configuration change request message may be transmitted in any suitable format or using any suitable protocol. One example is shown in FIG. 8. In this example, the power transfer configuration change request message is referred to as a Specific ReQuest/next configuration (SRQ/nc) data packet, which is transmitted from the power receiver to the power transmitter. In this example, the SRQ/nc message contains an eight-bit data field, but only one data bit b ₀ of this data field is used. This data bit indicates the direction of the request, ie whether the specified request is for a power transfer configuration with an increased or decreased maximum power limit.

In various embodiments, said power transmitter may also respond to said message with a request to change the power transmission configuration and, in particular, may acknowledge said request in its response. The response message, in particular, may indicate the time of change of the power transmission configuration. The response message, in particular, may indicate the time for the specified change, or the specified time of the response message may itself indicate the time to change the power transmission configuration. For example, the power transmitter may proceed to change the power transmission configuration after a predetermined time after the transmission of the response message.

As a specific example, the response message may be one of the following:

ACK : The requested new power transfer configuration becomes active within the specified (TBD) number of ms after the acknowledgment of the SRQ/en data packet;

NAK : The power transmitter has rejected the request and is continuing to use the current power transfer configuration (eg because a switchover could over-capacity the power supply in the current operating mode).

In some embodiments, the power transmitter may initiate a potential reconfiguration of the power transfer.

For example, the first configuration controller 309 may be configured to transmit a power configuration message in response to detecting that the power transfer performance satisfies the criterion, and in particular in response to detecting that the current power level of the power transmitter exceeds a threshold. , wherein said threshold depends on the maximum power limit in the current power transmission configuration.

For example, the first configuration controller 309 may continuously monitor the power level of the drive signal and compare it to the maximum power limit for the current power transfer configuration. If the (e.g., low-pass filtered) drive signal power level exceeds, say, 90% of the maximum power limit, the first configuration controller 309 may judge whether it is appropriate to switch to a power transfer configuration having a higher maximum power limit, and accordingly , start transmitting the power configuration message.

As another example, the first configuration controller 309 can monitor the frequency of the drive signal, and if it deviates too much from the desired resonant frequency of the tank circuit containing the transmitter coil 103 (indicating that the drive signal is substantially detuned from the nominal operating mode with to reduce the power of the power transmission signal for the current voltage amplitude), said power transmitter may proceed to transmit a power configuration message.

In this case, the transmission of the power configuration message accordingly not only provides voltage amplitude information for potential power transmission configurations, but also provides an indication that a change in the power transmission configuration is required/requested by the power transmitter. For example, in the two examples above, the power configuration message may indicate a decision to switch to a power transmission configuration with a higher maximum power limit and a decision to switch to a power transmission configuration with a lower maximum power limit, respectively. In some such implementations, the power configuration message may further include an indication of whether a switch to a higher or lower maximum power limit is required.

In some embodiments, the power receiver may initiate a change in the power transfer configuration. For example, similar to the approach described for the power transmitter, the second configuration controller 609 may determine the current level of extracted power and compare it with a threshold value reflecting the maximum power limit for the current power transmission configuration. Alternatively or additionally, it can measure the frequency of the power transmission signal and detect if the indicated frequency deviates too much from the nominal value.

The detection of such performance may be detection of a preference for changing the power transmission configuration, and in response, said power receiver may send a message requesting power configuration information to the power transmitter. In some implementations, this message may be a request to the power transmitter to transmit a power configuration message, and accordingly, the power transmitter may transmit said power configuration message, thereby providing the power receiver with information about the possibility of changing the power transmission configuration, and also about the corresponding consequences for the voltage amplitude.

A specific example of a possible messaging regarding a power receiver-initiated power transfer configuration change is shown in FIG. 9, and a possible exchange of messages regarding a power receiver-initiated power transfer configuration change is shown in FIG. 10. These examples include the following messages:

CE The (power) control error used by the power receiver to control its power and voltage levels to the appropriate target points.

RP/0 Received power packet used by the power receiver to inform the power transmitter of the amount of power received.

ACK Acknowledgment; used by the power transmitter to indicate that it is accepting a request.

NEGO Request for approval; used by the power receiver to initiate the matching sequence.

GRQ/psc General query/power supply configuration; used by the power receiver to request the power transmitter to send a PSC message.

PSC Power supply configuration; used by the power transmitter to transmit parameters for the next higher and next lower power configurations.

SRQ/nc Special request/next configuration; used by the power receiver to request the next higher or lower configuration.

SRQ/en Special request/completion of negotiation; used by the power receiver to terminate the negotiation sequence and indicate that the negotiated configuration should become active within a specified number of milliseconds.

In some implementations, the power receiver, as noted above, can determine if a change in voltage amplitude associated with switching the power transmission configuration will result in an unacceptable overvoltage or undervoltage condition, and if not, proceed to send a configuration change request message. energy transfer.

In some embodiments, the power receiver may be configured to compensate for the operation of the power receiver prior to switching to said power transfer configuration such that the resulting voltage change becomes acceptable even if it did not occur without some change in operation.

For example, the second configuration controller 609 may be configured, before changing the power transfer configuration, to modify the power transfer operation to change the induced voltage in the opposite direction of the voltage change that will occur in a subsequent power transfer configuration change.

For example, for a change that increases the amplitude of the drive signal voltage and thus results in an increase in the transient voltage in the receiver coil 107 when the power transfer configuration is changed, the second configuration controller 609 may proceed to reduce the induced voltage in the receiver coil 107 before said change. . When this change then occurs, the voltage across the receiver coil 107 may increase, but due to the previous voltage drop, this increase may be acceptable and will not lead to damaging overvoltage conditions, for example.

In some embodiments, the second configuration controller 609 may be configured to change the load impedance prior to switching to the specified power transfer configuration, and in particular, this change in load impedance may be performed along with a change in the induced voltage.

For example, power transfer may continue with a load of the power transfer signal that is close to the maximum power limit for the current power transfer configuration. Accordingly, it may be preferable to switch to the next higher maximum power limit, and this may be detected by the second configuration controller 609 (eg, based on receipt of a power configuration message or based on its own estimate of power transfer characteristics). Accordingly, it can send a message to the power transmitter requesting a change in the power transmission configuration and at the same time continue to reduce the impedance/resistance, resulting in a lower voltage and higher current, providing the same level of power but at a lower voltage. After changing the power transmission configuration, the impedance can be changed again according to the new conditions.

As a specific example, the situation described above can be considered where the power transmitter can operate in a 10W (5V, 2A) configuration, with the power receiver setting its operating mode to 8V, 1A. When the power transmitter switches to the next higher high configuration, such as 12W (12V, 1A), the power receiver will initially receive a voltage of 12/5*8=19.5V and a current of 2.4A, which is far beyond the capability of the power transmitter in this configuration. Accordingly, power transmission may be interrupted due to the generated overvoltage or overpower condition. To prevent this situation from occurring, the power receiver must set a power level before switching, for example, 4 V, 0.5 A. In the latter case, after switching, the power receiver operates at 12*/5*4=9.6 V, 1.2 A (i.e. 11.5 W assuming no loss).

A similar example when switching to a lower power configuration would be when the power transmitter is operating in a 12V, 1A configuration and the power receiver is only receiving 4W (eg 5V, 0.8A). This system can then switch to the next lower level configuration for the power transmitter, for example 5 V, 1.5 A. If this switch is performed without preparing the power receiver, it will receive a voltage of 5/12 * 5 = 2.1 V after switching, which may be too low to support its operation (i.e. undervoltage). Accordingly, this will also lead to the termination of energy transmission. However, this problem can be solved by increasing the induced voltage in preparation for switching.

The previous examples have focused on implementations in which the voltage amplitude of the drive signal applied to the output circuit from the driver is constant for any given power transfer configuration. However, this approach may also be suitable for implementations in which the voltage amplitude is not constant during operation of the power transmitter in a given power transfer configuration.

For example, in some embodiments, the power transmitter may be configured to operate over a given range of voltage amplitudes for each power transfer configuration. For example, each power transfer pattern may be given a maximum voltage amplitude, and thus each power transfer pattern may be associated with a different combination of maximum power limit and maximum voltage amplitude (limit) for the drive signal.

In such a case, the voltage amplitude indication conveyed in the power configuration message may indicate the maximum voltage amplitude (limit value) for the respective potential power transfer configuration. Accordingly, the power receiver may be configured to determine the maximum voltage transient or voltage drop that may occur when switching from a current power transfer configuration to a potential power transfer configuration. For example, when switching to a new power transmission configuration, the power transmitter can always start at the maximum voltage amplitude, and the power receiver that monitors the current voltage amplitude (for example, by comparing the voltage induced at a given time with the voltage that occurred immediately after switching the power transmitter to the current configuration power transfer) can determine the induced voltage amplitude immediately after switching to a new power transfer configuration.

Similarly, the specified voltage amplitude for a given power transfer configuration may have a minimum limit value, and the power configuration message may additionally or alternatively indicate a minimum voltage amplitude limit for a potential power transfer configuration. Accordingly, this may allow the power receiver to determine the smallest induced voltage that will be experienced immediately after a power transfer configuration change.

In some embodiments, the voltage amplitude indicated in the power configuration message may not be a maximum and/or minimum voltage amplitude limit, but may be, for example, a nominal or initial voltage amplitude. For example, the power transmitter may be configured, upon switching the power transfer configuration, to initiate a new power transfer pattern with a given voltage amplitude for the drive signal, and this initial voltage amplitude may be communicated to the power receiver in a power configuration message. The power receiver can accordingly determine the induced voltage immediately after switching the power transfer configuration, for example by analyzing the initial voltage amplitude for the potential power transfer configuration in relation to the current voltage amplitude or in relation to the initial voltage amplitude for the current power transmission configuration. After switching, the voltage amplitude can be subsequently changed by the power receiver, but this is usually done so slowly that the power receiver does not experience any transients or spikes.

The voltage amplitude, for example, may be indicated in the power configuration message as a relative value with respect to, for example, the initial voltage amplitude for the current power transfer configuration. In some embodiments, the voltage amplitude for a potential power transfer configuration may be provided as a relative indication of the current voltage amplitude. For example, a relationship between the initial voltage amplitude for a potential power transfer configuration and the current voltage amplitude may be included in the power configuration message. This can help the power receiver detect the step voltage when switching the power transfer configuration (eg, the receiver does not need to track changes in voltage amplitude) and is generally feasible due to the very slow change in voltage amplitude.

This variable voltage amplitude approach, in particular, may allow or support implementations in which the power level of the power transmission signal is controlled (at least in part) by varying the voltage amplitude of the drive signal. For example, an approach may be provided in which the voltage amplitude of the drive signal is adapted based on power control error messages from the power receiver.

It should be understood that in the above description, embodiments of the present invention are presented with reference to various functional circuits, blocks, and processors for clarity. However, it is clear that any suitable distribution of functionality between different functional circuits, blocks or processors can be used without departing from the principle of the present invention. For example, functionality shown as being performed by separate processors or controllers may be performed by the same processor or controllers. Therefore, references to specific functional blocks or diagrams should be considered only as references to suitable means for providing the described functionality, and not as an indication of a strict logical or physical structure or organization.

The present invention may be implemented in any suitable form, including hardware, software, firmware, or any combination thereof. The present invention may also be implemented at least in part as computer software running on one or more data processors and/or digital signal processors. The elements and components of one embodiment of the present invention may be physically, functionally and logically implemented in any suitable manner. Indeed, functionality may be implemented in a single block, in multiple blocks, or as part of other functional blocks. Because of this, the present invention may be implemented in a single unit, or may be physically or functionally distributed among different units, circuits, and processors.

Although the present invention has been described in terms of some embodiments, it is not limited to the specific form set forth herein. The scope of protection of the present invention is limited only by the appended claims. In addition, although it may seem that the feature is described in terms of specific implementations, it will be obvious to a person skilled in the art that various features of the described embodiments can be combined in accordance with the present invention. In the claims, the term "comprising" does not exclude the presence of other elements or steps.

It is understood that reference to a preferred value does not imply any limitation other than that it is the value defined in the foreign object detection initialization configuration, i.e., it is preferred by virtue of being determined by the adaptation process. References to the preferred value may be replaced by, for example, references to the first value.

In addition, although a plurality of means, elements, circuits, or method steps are listed individually, they may be implemented, for example, using a single circuit, block, or processor. In addition, although individual features may be included in different claims, they may preferably be combined and their inclusion in different claims does not mean that a combination of features is not possible and/or not preferred. In addition, the inclusion of a feature in one category of claims does not imply a limitation to that category, but rather indicates that the feature is equally applicable to other categories of claims, where appropriate. Furthermore, the order of the features in the claims does not imply any particular order in which the features are to operate, and in particular, the order of the individual steps in the claims does not imply that the steps must be performed in that order. Rather, the steps may be performed in any suitable order. In addition, references in the singular do not exclude the plural. Thus, references to the grammatical means of expressing the singular form, as well as the terms "first", "second", etc. do not exclude sets. Reference positions in the claims are provided solely as an illustrative example and should in no way be construed as limiting the scope of the claims.

Claims (37)

1. An energy transmitter (101) for wirelessly supplying energy to an energy receiver (105) by means of an electromagnetic energy transmission signal, comprising: an output circuit (302, 103) comprising a transmitter coil (103) for generating a power transmission signal in response to a drive signal supplied to the output circuit (302, 103); an exciter (301) for generating an excitation signal; a configuration controller (309) for switching between a set of power transfer configurations, wherein said power transfer patterns of the set of power transfer configurations have different combinations of maximum power limit and voltage amplitude for the drive signal; a receiver (305) for receiving from the energy receiver (105) a message with a request to change the energy transmission configuration; and differing in that it also contains a transmitter (307) for transmitting a power configuration message to a power receiver (105), the power configuration message comprising data indicative of a voltage amplitude for a first power transmission pattern of the set of power transmission patterns; wherein the configuration controller (309) is configured to switch the power transmitter (101) to the first power transmission configuration in response to said power transmission configuration change request message. 2. The power transmitter of claim 1, wherein the data indicates a relative difference between the voltage amplitude in the first power transmission configuration and the voltage amplitude in the current power transmission configuration. 3. The power transmitter of claim 2, wherein the data indicates a relationship between a voltage amplitude in the first power transmission configuration and a voltage amplitude in the current power transmission configuration. 4. The power transmitter according to any preceding claim, wherein the first power transmission configuration is a power transmission configuration of a set of power transmission configurations having a maximum power limit that is at least one of the next higher maximum power limit and the next lower maximum power limit for the maximum power limit in the current power transfer configuration. 5. The power transmitter according to any preceding claim, wherein the power configuration message comprises data indicating a voltage amplitude for a second power transmission pattern from said set of power transmission patterns, wherein the first power transmission pattern is a power transmission pattern from said set of power transmission patterns. having a maximum power limit value representing the next higher maximum power limit value for the maximum power limit value in the current power transmission configuration, and the second power transmission configuration is a power transmission configuration from the specified set of power transmission configurations having a maximum power limit value, representing the next lower maximum power limit for the maximum power limit in the current power transfer configuration. 6. The power transmitter according to any preceding claim, wherein the given data value indicating the voltage amplitude indicates that the given set of power transmission configurations does not contain a power transmission configuration that has a higher maximum power limit value than the maximum power limit value in current power transmission configuration. 7. The power transmitter of any preceding claim, wherein the configuration controller (309) is configured to transmit a power configuration message in response to detecting that the power transfer performance meets the criterion. 8. The power transmitter according to any previous claim, wherein the configuration controller (309) is configured to transmit a power configuration message in response to detecting that the current power level of the power transmitter exceeds a threshold, said threshold being dependent on a maximum power limit. in the current power transmission configuration. 9. The power transmitter of any preceding claim, wherein the configuration controller (309) is configured to transmit a power configuration message in response to receiving a power configuration information request message from the power receiver. 10. The power transmitter according to any preceding claim, wherein the configuration controller (309) is configured to switch the power transmitter to the first power transfer configuration after transmitting an acknowledgment message to the power receiver, said acknowledgment message acknowledging the request message received from the power receiver. 11. An energy receiver for wirelessly receiving energy from an energy transmitter (101) by means of an electromagnetic energy transmission signal, comprising: an input circuit (601, 107) comprising a power receiver coil (107) configured to extract power from the power transmission signal; a configuration controller (609) configured to detect a power transmission configuration change preference for switching the power transmitter to a first power transmission configuration of the set of power transmission configurations; and differing in that it also contains a receiver (605) for receiving a power configuration message from a power transmitter (101), wherein said power configuration message comprises data indicating a drive signal voltage amplitude for at least a first power transmission configuration from a set of power transmission configurations, said power transmission configurations from the specified set of power transmission configurations have different combinations of the maximum power limit value and voltage amplitude, and the excitation signal is intended for the output circuit (302, 103) of the power transmitter (101), containing the transmitter coil (103) for generating a power transmission signal in response to the signal excitation supplied to the output circuit; a transmitter (607) for transmitting a power transmission configuration change request message to the power transmitter in response to detecting a power transmission configuration change preference, said power transmission configuration change request message comprising a request to switch the power transmitter to the first power transmission configuration. 12. The power receiver of claim 11, wherein the configuration controller (609) is configured to control the power transfer to change the voltage induced in the coil of the power receiver before changing the power transfer configuration to the first power transfer configuration. 13. The power receiver of claim 11 or 12, wherein the configuration controller (609) is configured to change the load impedance for the power receiver coil before changing the power transfer configuration to the first power transfer configuration. 14. A method of operating the energy transmitter (101) for wirelessly supplying energy to the energy receiver (105) by means of an electromagnetic energy transmission signal, including: generating a power transmission signal by the transmission coil (103) in the output circuit (302, 103) in response to the drive signal applied to the output circuit (302, 103); generating an excitation signal; switching between a set of power transmission configurations, wherein said power transmission patterns of said set of power transmission configurations have different combinations of maximum power limit and voltage amplitude for the drive signal; transmitting a power configuration message to a power receiver (105), said power configuration message comprising data indicative of a voltage amplitude for a first power transmission configuration from said set of power transmission configurations; receiving from the energy receiver (105) a request message to change the energy transmission configuration; And wherein said switching between said set of power transfer configurations switches the power transmitter (101) to the first power transfer configuration in response to the power transfer configuration change request message. 15. The method of operation of the energy receiver for wirelessly receiving energy from the energy transmitter (101) by means of an electromagnetic energy transmission signal, including: extracting energy by means of the energy receiver coil (107) from the energy transmission signal; receiving a power configuration message from the power transmitter (101), wherein said power configuration message contains data indicating a voltage amplitude of the drive signal for at least a first power transmission configuration from a set of power transmission configurations, said power transmission configurations from a specified set of transmission configurations energy have various combinations of maximum power limit and voltage amplitude, and the excitation signal is intended for the output circuit (302, 103) of the energy transmitter (101), containing the transmitter coil (103) for generating an energy transmission signal in response to the excitation signal supplied to the output chain; detecting a power transmission configuration change preference for switching the power transmitter to the first power transmission configuration; And transmitting a power transmission configuration change request message to the power transmitter in response to detecting a power transmission configuration change preference, said power transmission configuration change request message comprising a request to switch said power transmitter to the first power transmission configuration. 16. A wireless power transmission system, comprising an energy transmitter (101) according to any one of paragraphs. 1-10 and receiver (105) energy according to any one of paragraphs. 11-13, wherein the system is configured to wirelessly power the power receiver (105) from the power transmitter (101) via an electromagnetic power transmission signal.

Images