Patent for “System and Method for Power Transfer”

Communications – Aaron Rex KEITH, Arunim KUMAR, Junbo ZENG, Lewis Freeth Harpham, Paul David MARSON, Sander VOCKE, Ya-Ting Wang, Apple Inc

Search Patent for “System and Method for Power Transfer”

Abstract for “System and Method for Power Transfer”

A system for inductive power transfers that can selectively transmit power in multiple modes based upon characteristics of a power receiver. It also determines which transmitter coils to drive based only on the received signal strength information. Inductive power transfer transmitters may be able to detect the characteristics of a power receiver and control the mode of power transfer. They can also control which transmitter coils are being driven using signal strength information from a power receiver. The power transmitter could have slugs made of magnetically permeable materials within common coil winding openings. Additionally, the transmitter coils might be composed of multiple parallel windings.

Background for “System and Method for Power Transfer”

IPT technology is a growing area. IPT systems can be used in many applications with different configurations. IPT systems are used in charging mats, which is one example of such an application. These pads are also known as charging mats. These charging mats can be used to charge or power wireless devices, such as smartphones.

The charging mat typically includes a transmitter with one or more power transmissions coils that are parallel to the charging surface. The transmitter drives the transmitting coils so that the transmitting ones generate a magnetic field at a specific time in the vicinity of the planar surface. The time-varying magnetic field created by the portable electronic device is able to induce an alternating current within the receiver coil of the appropriate receiver. This can be a receiver that has been integrated into the device or placed on the planar surface. The power received can then be used to charge batteries or power other loads.

The problem with charging mat design is that it is difficult to ensure inductive power transfer is efficient. A way to ensure that the transmitting and receiving coils are aligned precisely is to use a precise alignment. You can achieve this by markings or indentations being made on the planar charging surface. This will ensure that the coils are aligned when the user places their device on the mat. This approach is not the best as it requires that the user place the device on the charging mat carefully.

Another problem with charging mat designs is the ability to charge multiple devices simultaneously in a cost-effective and efficient manner. Conventional designs only use one large transmitting coil that covers the entire charging mat. One or more devices can be placed on this charging mat. This gives users more flexibility in placing a device on the charging surface. The magnetic field generated by large transmitting coils may not be uniform and have weak spots. The charging mat is located towards the middle. Furthermore, the whole surface is being?powered’. It is possible that parts of the surface are not being charged could pose a danger to safety.

A number of smaller transmitting coils is another way to multi-device charge. The charging mat uses a suitable detection method to detect the device’s position and activates the closest transmitting coil. This ensures safe and efficient power transfer. This allows for greater flexibility in the placement of a device. However, due to cancelling effects of nearby coils, weak spots can occur where receivers don’t receive enough power.

“An additional problem occurs when a non receiver is brought within the range of the transmitter and an unwelcome current (and heat) is inducible therein. These non-receivers can be called parasitic loads, or foreign objects. Although it is possible to detect the presence of a receiver device, it may be more difficult to identify the receiver that is compatible with the transmitter. Inefficient power transfer to non-compatible receivers can lead to unwanted energy loss, or receiver and transmitter failure.

A manually operated power switch can be added to the transmitter to solve the above problems. Although this allows for the control of when the transmitter should power up, it does not provide the convenience that many IPT systems seek. This requires that the user manually turn off the transmitter after removing the receiver. It does not allow for parasitic loads to be placed in the vicinity of the transmitter.

“The invention provides an efficient and reliable wireless power transfer system for multi-device powering.

“One exemplary embodiment provides a system for power transmission and a method of operating it. The system comprises a power transmitter as well as a receiver. The power transmitter is composed of multiple transmitter coils that can be controlled to transmit power in a variety of modes. To control the power transfer mode, the controller can detect the characteristics of the power receiver.

“Accordingly, there is a system for power transmission that includes a power transmitter with at least one receiver and a power transmitter. The power transmitter has a plurality transmitter coils that can be controlled to transmit power in a variety of modes.

“The characteristics may include the ability of the power receiver to control power flow to a receiver’s load.”

“The controller can be programmed to communicate with the power receiver, and to receive information about these characteristics from the power receiver. The controller can be programmed to transmit a power signal through electromagnetic induction between power transmitter and receiver.

“The power transmitter could include an object detector, which may be used to detect objects in a magnetic field generated by object detection coils.”

“The controller can extract the receiver device version information using modulated power signals between coupled transmitter coils in order to control the mode for power transfer based upon the version information.”

The controller can also extract configuration information about the receiver device from the modulated power signals that pass between the receiver coils and coupled transmitter coils. This information is used to control power transfer mode based on the configuration information. Configuration information can be used to control the maximum power that is transmitted to the receiver and/or the number transmitter coils required to power it.

“During the receiver location phase, before energy transfer, the controller can selectively control which transmitter coils are being driven. This is based on information received by the receiver. It measures the signal strength received by a driven transmitter. The control circuit can connect sequentially a drive signal from power conditioning to each power transmitting coil during the receiver location phase to energise each coil at a predetermined time.

“Accordingly to another exemplary embodiment, there is provided an Inductive Power Transfer Transmitter for providing power to an Inductive Power Transfer Receiver having one or more receiver coils. The transmitter includes:

“During the receiver position phase, the control circuit sequentially connects the drive signal from power conditioning circuit to each power transmitting coil to energise them for a predetermined period. This is the expected time at which a signal strength packet will be received.

The control circuit may combine information received from a transmitter in response to a coil being driven and the driven coil to determine which of the transmitter coils to be driven. The modulation of power signals between the coupled transmitter-receiver coils may be detected by a communications module. This information can be used to determine the degree of coupling between the transmitter and receiver coil pairs. Preferably, this is done by extracting a signal value from a packet sent by a recipient to calculate the degree of coupling.

“Following selections of one or more transmitter coils, one or more transmitter coils may be activated for a longer time than the predetermined time to enable the receiver to receive additional packets. One or more transmitter coils may be selected by the control circuit to provide power to receiver. One transmitter coil may have the highest associated strength value. Two or more transmitter coils can be chosen. The transmitter coil with the highest associated strength value and the transmitter loop with the next highest associated strength value are the two transmitter coils.

“The control circuit can control the power conditioner circuit in response to the characteristics of the power receiver contained within the information received by transmitter.”

“The transmitter could include an object detection device and the control system might energise transmitter coils when the object detector system detects an item.”

“The communications module can extract receiver identification from modulated signals between coupled transmitter-receiver coils, and control the operation of the power conditioning circuit based upon the identification information.”

“Accordingly, another exemplary embodiment provides, in an IPT system having an IPT transmitter having a plurality transmitter coils and an IPT receiver having one or multiple receiver coils, a way of selectively driving one of the transmitter coils. This includes:

The expected time of receipt for a signal strength packet may be predetermined. A power signal may be modulated between the receiver and power transmitter to send signals to transmitter. A signal strength packet may contain the signal strength information, which may also include information about the receiver. After the receiver location phase, identification packets may be sent to the coupled transmitter with receiver identification information.

The receiver identification information may be used to determine the version information. Version information may determine the mode of operation for the transmitter. An identification packet may contain a version code that identifies the mode of operation for the receiver. An identification packet might also contain a manufacturer code that identifies the manufacturer of the receiver. An identification packet might also contain a unique Identifier.

“The communications circuit transmits configuration information from the receiver device to a coupled transmitter. Preferably, this configuration packet is sent. The maximum power that can be transmitted may be included in the configuration packet. The characteristics of the power receiver may influence the power transmitter’s ability to supply power to it.

“If every packet contains a receiver ID code, preferably a unique one, then the mode for power transfer may be based upon the receiver identification code.”

“Accordingly to another exemplary embodiment, there is provided an inductive energy transfer receiver which includes:

“Another exemplary embodiment provides an inductive power transfer transmitter, which includes a plurality adjacent transmitter coils. Each winding defines a central opening, with the central openings from adjacent coils defining common opens. Slugs made of magnetically permeable materials are provided within at least some common openings and protruding over the transmitter coils.

“The slugs could be propelled from magnetically permeable material that is provided beneath the coils. Multiple layers of transmitter coils within close proximity may exist, and they may be interleaved.

“Another exemplary embodiment provides a transmitter in which each winding defines an opening, and adjacent coils’ central openings define common openings. Slugs made of magnetically permeable materials are placed within at least some common openings.”

“Each slug could protrude over the top of the transmitter coils. Each transmitter coil may have a number of winding layers, with some coils offset and others interleaved. A layer of magnetically permeable material may be used to project the slugs.

“The windings for each layer of at most some coils can be made as a plurality parallel windings, electrically connected in parallel. Each layer of at least three coils can have its windings formed by three parallel windings that are electrically connected in parallel. Between layers, the radial displacement of at most some of the parallel windsings can change. One design has a pair parallel windings that alternate between being the closest and the farthest from the coil.

“Another exemplary embodiment provides an inductive power transfer transmitter that includes a plurality transmitter coils. Each coil is composed of a plurality winding layers, and the windings are electrically connected in parallel.”

“The parallel windings can be made on each layer and connected between layers. Each layer may have three parallel windings that are electrically connected in parallel. There may be a radial displacement between the layers of at least one of the parallel windings. For example, a pair of parallel winds that alternate between being nearest to the center of the coil and the farthest from it between layers.

“The parallel windings from each turn can be distributed among winding layers, preferably between two layers. You can also offset the parallel windings between layers.

A slug made of magnetically permeable materials may extend sufficiently high above the coils to reduce the induced currents. The slug can extend to the top of each winding, or approximately 1 mm above each winding’s top. To accommodate the slugs, four common openings can be found within each transmitter coil. To reduce the induced currents in transmitter coils, an air gap can be created between each transmitter coil & each slug.

“According another example, there is an inductive power transmitter with a plurality transmitter coils that can be selectively made to transmit power in a plurality mode under control of a controller to the receiver coil of at most one power receiver. The controller is designed to detect characteristics of power receivers in order to control power transfer mode.”

“The characteristics may include the inclusion of circuitry to control power flow to the load of the receiver. The controller can be set up to communicate with power receivers and receive information from power receivers about such characteristics. This could include modulating power signals transmitted by electromagnetic induction between power transmitter and receiver.

“The controller can extract the receiver device version information using modulated power signals that pass between the receiver coils and coupled transmitter coils. Then, it controls the mode for power transfer based upon the version information.”

The version information may control the maximum power that can be transmitted to the receiver and/or the number transmitter coils required to power it.

“Accordingly to another exemplary embodiment, there is provided an inductive energy transfer receiver which includes:

“The receiver can include a powerflow controller to control power flow to a load of receiver. The characteristics communicated through the communication circuit include power flow control characteristics.”

“The receiver’s characteristics may include version information. This may indicate the mode for power transfer. This version information can be included in a packet that is sent after a signal strength packet.

“The characteristics could also include configuration information. This may include the number and type of transmitter coils that must be driven to supply power to one or more receiver coils.

“Signal strength information relating to the strength of a power signals received from a power transmitter could be sent before other communications.

“It is recognized that the terms ‘comprise?, and?comprises? are interchangeable. “It is acknowledged that the terms?comprise?,?comprises??????? and?comprising?” In different jurisdictions, these terms may be assigned an exclusive or inclusive meaning. These terms, except where otherwise noted, are meant to have an inclusive meaning. This means that they will be understood to include the components directly referred to in this specification.

“References to prior art in this specification do not mean that they are part of the common knowledge.”

“FIG. “FIG. A transmitter or charging pad is shown in the wireless power transfer system 100. The wireless power transfer system 100 is illustrated as having a transmitter or charging?pad? 102 containing a plurality consumer electronic devices (104), so that the devices can be charged with electricity in a wireless or non-contact manner. The illustrated example shows that the electrical power between the pads and the devices is provided by electromagnetic induction (IPT) or inductive power transfer, using loose-coupling techniques between receiver and transmitter electronics. Other types of wireless power transfer are possible with such a system, including capacitive power transfer.

The transmitter and receiver electronics of charging pad 102, 104 can be arranged so that the user can choose the placement of the devices on the pads. The transmitter can charge multiple receiver devices at once. This is called “spatial freedom”. The distance between plural receivers and transmitters is substantially unlimited. This is described as follows:

FIG. 2 shows an exemplary configuration for a wireless power transfer device 200. 2. The transmitter 202 can be used to transmit power to multiple receivers (204, 206 and 208) Three receivers of a consumer device configuration are shown in this example. FIG. FIG. The transmitter can be scaled to power multiple receiver devices, including plural phones, tablets, laptops, phablets, and other types. Each device has its own power level and spatial dimensions. A smartphone can require between 5 and 7.5 Watts of power, while a tablet might require around 15 Watts to charge its respective batteries.

The block diagram of the transmitter 202 shows its electronics and parts. A power supply 210 supplies power to the transmitter for power transfer to its receivers. The power supply 220 can supply AC or DC power to transmitter 202. The power supply 210 for AC power supply may include Mains power and an input method via a cabled connector. However, other AC power supplies are also possible. The power supply 210 for DC power supply can be batteries, a regulated DC supply, or a USB connection to a computer or other similar devices. The circuitry of transmitter 202 converts input power into signals that can be transmitted via power transmission elements (212). An array of 214 transmission elements is provided for the 212 elements. The transmission elements 212 can transmit power to one or more elements of a receiver device 204-208.

“IPT is understood by those who are skilled in the art to be inductive elements that are provided as primary (transmission) and secondary (receiving), coils. Power is transferred between them via a magnetic field created when an alternating current is passed through the coils. FIG. FIG. 2 shows the receiver coils (216) distant from the transmission coils (212). The groups of coupled transmitter-receiver coils are illustrated with similar hatching. This is just for explanation, and in operation the receivers are over the transmitter coils.

“It is understood the use of the term “coils”? Inductive?coils are what is being used herein. Inductive?coils are electrically conductive wires that are wound into three-dimensional coil shapes or planar coil shapes. Electrically conductive material can be fabricated using PCB techniques, stamping, printing (e.g. screen- or 3D printing), into three-dimensional coil shapes. These coil shapes can be overlaid with one or more PCB?layers? and other coil-like shapes. The term “coils” is used in this context. This is not intended to be restrictive. In FIG. 2, the receiver and transmitter coils are shown as having an oval shape. 2. This is only an example. Other two-dimensional shapes such as square, rectangular, circular, triangular, square and rectangular are also possible.

“To ensure efficient operation of this system, the transmitter 202 must only power the transmitter coils 221 that can be coupled with the receiver coils 226 of the proximate receivers. The power supplied is used to power the receivers and not the transmitter coils. This selective operation requires that you know the position of the receiver coils relative to the transmitter coils. We will explain this in more detail later.

“Providing driving electronics for each coil or group of coils is the easiest way to selectively power multiple transmitter coils of array 214 is the simplest. Although this is a simple solution, it requires a lot of electronic circuitry, which can increase the complexity, cost, and size of the circuit. Circuit complexity increases, which means higher component counts. This can lead to potential losses and compromise the efficiency of IPT. Consumer electronics manufacturers have small financial margins and need to optimise their costs. This is why increased cost is a major concern. The present invention uses common driving electronics to control all the IPT transmitters. Although this simplifies the circuitry, it increases complexity in the way that the driving circuitry is controlled. This is acceptable when the control methods described later are used. FIG. 2 illustrates the transmitter driving electronics. FIG. 2 is the driving or control circuitry 218. Control circuitry 218 comprises a controller 220 and a transmit power conditioner 222. A selector 224 is also included.

“The controller 220 may be provided as a digital controller in the form of a programmable integrated circuit, such as microcontroller or microprocessor, or as an analog controller in the form of discrete circuit components, and may include or be a proportional-integral-derivative (PID) controller. A microcontroller is used in the examples of driving circuitry. However, it can also be used to drive the coils and as the main processing circuitry for the transmitter. However, those who are skilled in the art know that different forms of controllers may be equally applicable depending on the specific application.

The transmitted power conditioner 222, which is used to condition input power for the transmitter coils, can be configured according to the power supply 210 and requirements of the transmitter coil circuitry. If the power supply supplies DC power, then the transmitted power converter 222 is a DC/AC inverter with power rectification functions. However, if the supply 210 supplies AC power the transmitted power conditioner 222, which is an AC-DC converter with power regulation and a DC/AC inverter, the transmitted conditioner 222 provides AC to AC power conditioning via a DC transmission line. One inverter is used to drive the transmitter element array in each case. The transmitted power conditioner 222, which is connected to the power supply 210, can be configured as an AC-AC converter. However, such converters are not usually suitable for IPT applications because they cannot generate high frequency outputs. The power rectifying DC-AC inverter may be provided as a switch-based rectifier, such as a half-bridge rectifier or full-bridge rectifier having switches, such as diode based switches, or semiconductor switches, such as transistors, field-effect transistors (FETs) or Metal-Oxide-Semiconductor FETs (MOSFETs), in either non-synchronous or synchronous configurations, as is well known to those skilled in the art. A power-regulating DC-AC converter can be an AC-to DC converter (ADC), combined with a step up (Boost), a step down (Buck), or any other type of converter suitable for controlling the power in the particular application of system 200. The driving circuitry shown herein includes a power supply 210 that supplies AC at Mains rating. The transmitter or transmitted power conditioning has an ADC to convert AC power from the power supply210 to DC and a Buck-Boost converter for regulation of DC power. A half-bridge rectifier with a pair FETs to rectify DC power, thus providing rectified power to transmission coils (212) to induce the required magnetic flux. However, those skilled in the art know that different forms of regulators and rectifiers may be used according to suit the specific application.

The selector 224 can be provided either as a battery, or an array of switches, separate from the respective transmitter coils 212, or separately integrated with the coils 212, in the respective transmission circuits. A demultiplexer or shift register may be included in the selector 224 to drive the switches in a way that is well understood by skilled artisans. We will discuss the operation and effects of these components in greater detail later.

The array 214 of transmitters coils 212 can be configured in many ways. It is possible to configure the transmitter coils so that they have the same configuration and dimensions as the receiver coils. This allows for the possibility of having coupled pairs of receiver and transmitter coils. The transmitter coils can be configured differently to the receiver coils, or to be smaller or larger than the receiver coils. Different types of receiver devices might have different-sized and configured receiver coils. The system and method of this invention may support a combination of these relative configurations. FIG. 2 illustrates this. FIG. 2 shows the transmitter coils 212, which are smaller than the receiver coils 216, but have the same shape, i.e., they are generally oval. Plural transmitter coils 212 may be connected to one receiver coil 216. This configuration is illustrated by the hatched transmitter group 212a, 212b, and 212c. FIG. 2 shows that the group transmitter coils are chosen based on the position of the receiver coil above it, and the relative orientation.”

“The array 214 in FIG. 2. is the simplest way to arrange the transmitter coils 212. This is a repeating pattern of transmitter coils in a single plane or layer, with each coil generally being co-planar to all other coils of an array. This configuration is simple and has its benefits, but there are other configurations that are possible. For example, multiple-layered or multi-planar arrays of coils, with or without interlayer offsets, overlaps, or regular or irregularly-arranged transmitter coils. These arrays of greater complexity offer other benefits, such as better uniformity in the magnetic field coupling. Each embodiment has its own unique array form, but the purpose of spatially-free, multi-device IPT Charging is shared by all.

“With further reference at FIG. 2. The transmitter 202 includes instrumentation 226 that can be used by the user of the system 200. As illustrated in FIG. 1. The controller 220, or any other control circuitry, may connect to the instrumentation 226 and be controlled by it.

“Selective operation of transmitter coils is dependent on knowing the position of receiver coils relative to transmitter coils. There are many techniques available to achieve this goal. The present invention employs a simple technique in an exemplary embodiment to detect the presence (e.g. within the charging range) of a receiver or another object. detection), and then determine the relative position of receiver coils with respect to transmitter coils (?fine?). detection). This is advantageous in the system described herein because sufficient powering of the plurality transmitter coils is required for fine detection only once a receiver has been detected. It allows for a substantial low power idle or sleep. The transmitter’s operating mode. The typical values for?low? are: Power should be below 100 mW. Preferably, below 50 mW. More preferably, in the range of a few to less than 20 mW.

“The receiver detection method according to the invention may include coarse detection and fine detection in two stages. FIG. FIG. 3 shows an example of a transmitter 302 in accordance with the system of this invention. As shown in FIG. FIG. 2 shows the transmitter 302 in block diagram form. It includes electronics such as transmission elements/coils 312, array 314, and driving circuitry 328, including a controller, transmitter power conditioner 322 or selector 324. The transmitter 302 also includes a detector 322 and a communications module 333. FIG. FIG. 4 shows an example of a transmitter with similar components/elements. It includes transmission elements/coils 412, 414, driving circuitry, 418, including a controller 422, selector 424 and a detector 428. A communications module 430 is also shown. The transmitted power conditioner 422, as shown, has a (BuckBoost) converter 432, and a (4-Band-bridge) rectifier 444. It should be noted that the components/elements in the transmitters 302 & 402 work in a similar way to the transmitter 202’s like components/elements. The detector and communications modules of each transmitter 328 & 428 are the same elements as the Figures.

The detector can be used in conjunction the controller to detect receivers coarsely, while the controller may be used in conjunction other circuitry for fine detection. The detector 428 can be used as a detection transmission elements 436 and 438. The detection transmission element 432 may be a coil that surrounds the array 414, which is the embodiment of the power transmission elements 412. Another embodiment of the detection transmission element 432 is a coil which surrounds the array 414 of the power transmission elements 412. The operation and configurations of the detection coils are described in PCT Publication No. The transmission element 432 is an example of the form described in WO 2014/070026. The detection element 436 determines if a transmitter is within a receiver’s reach, e.g., whether a receiver device such as a smartphone is placed on or removed from the charging surface or transmitter pad. The ‘coils’ are, as we have already stated, made of a variety of materials. The detector 328/428 can be made of either printed circuit coils, wound coils, or stamped coils with such dimensions and shapes that they are suitable for the particular application.

This detection can be described as follows. FIG. 4. The coils (436) are powered by the detection circuitry 438 via a power regulator (440) under the control of controller 420. The power regulator 440 converts power from a power supply to the detector 428. The power regulator 440 works in the same way as the transmitted power conditioner. It supplies a regulated AC signal (voltage/current), to the detector coil(s), 436 to create the necessary magnetic flux for coil detection. The power regulator 440 can be combined with a Buck, Boost, or Buck-Boost converter. FIG. 4 illustrates an exemplary embodiment. 4. The power regulator 440 is a Buck-Boost converter that receives DC voltage from a DC input 442. The DC power input 442 can be used as an AC adaptor, at which DC power or Mains AC power is supplied to the transmitter 402. The power regulator 440 can be part of the driving circuitry 408, depending on the relative voltage/current requirements for the power (transmitter coils) 412 or the detection coil(s), 436. FIG. 4 shows an exemplary embodiment. FIG. 4 illustrates an exemplary embodiment. Because the relative requirements of each component are different, separate drive electronics are required. The detector 428 (and controller 422) require a first voltage level while the transmitted power conditioner 422 requires a second voltage level. Transmission coils 412 and 422 require a second voltage level. These parameters will be described in detail later. After undergoing electromagnetic interference conditioning (444), the DC voltage from the DC power input 442 can be fed to the circuitry for the transmitter 402. This block contains common and differential modes filters for EMI noise suppression. The suppression of EMI noise improves the stability and responsiveness the transmitter circuitry, particularly when it is used in cellular communications environments.

“The simplest form of the detector is the?detection? The detector is basically a metal detection system. When the detector is powered, the coils of the detector oscillate at a frequency that is well known by those who are skilled in the art. The controller controls the detector’s detection circuitry, which measures the frequency of oscillation by counting the edges of the oscillating frequency signals within a time period. The frequency of oscillation occurs when a metallic object is near the detector coil(s) and the transmitter. This happens because the magnet flux that the coil emits absorbs energy from the metal. The amount of energy a metallic object absorbs will determine how much change occurs. A limit or threshold on the frequency of oscillation change can be set to detect a metal object. It can be detected. You can measure the change (i.e. detect) in a single period of time or over a series of time periods. The best methods of counting and detecting edges are well-known and not covered herein.

The frequency of the oscillation of the detector coil is determined by the selection of components in the detection circuitry. These components may include variable components. Dimensions and topology of detection coils must be chosen so that they are within a frequency range other than the frequency at which transmission coils operate. The receivers’ operation is not affected by the coarse detection of the detector. The detection frequency of the invention is approximately 1 MHz. Power transmission is approximately 100 kHz. (More specific values are discussed below). The predetermined (first time period) for detection at this frequency range is approximately 40 ms. The?search? procedure is described as follows: The constant operation of the detector coils and periodic sampling of the oscillation frequency are used to locate an object that is brought within the range of the transmitter. A (second) time interval of approximately 500 ms is required between detection?pulses. It is suitable for detecting objects even if they are not placed on the transmitter ‘pad. They can also be detected when objects are moved towards, along, and away from the transmitter. is defined as being within the sub-100 millimeter range (e.g., 3 mm to 30 mm), which is the charging range for the system. You can choose to have the second and first time periods be shorter or longer depending on how coarse the detection is. of detection required.”

The operation of transmitter coils and detection coils is not affected in any significant way. However, when charging occurs the oscillation frequency of detection coil(s). This can be explained in part by the presence of a receiver device at the charging surface of transmitters and partly due to the effect of the induced magnet field of larger detector coils. This effect is easily explained as sudden oscillation frequency changes are measured so that the effect on the charging sequence only shifts the baseline frequency delta measurement. We will discuss this in greater detail later.

The threshold of measured frequency changes for detection can either be determined experimentally, or through calibration. Or dynamically determined and used to determine a “rolling” value. Multiple receiver devices placed on the transmitter surface can result in an average frequency value. The exemplary embodiments described herein consider a variance of approximately 5% to 10% in the edge count to be environmental (e.g. background noise). Fig. 5(A)). 5(A) 5(B)). This is an?event? This is used to?trigger the event? The fine detection that will determine if an?object is detected. The fine detection will determine if the?object? is a receiver, or any other metallic object that was placed onto the transmitter. It should therefore not be powered, i.e. a so-called “foreign object”. “parasitic load?”, which is described in greater detail below.

FIGS. FIGS. 5(A) & 5(B), show that a frequency change threshold greater than 10% could be used for a sensitive event. Other factors should also be considered when setting the threshold to prevent false positives. “Fine detection methods are more energy-intensive and time-consuming.

Background variations may be affected by factors such as the presence of metal in the area around the system. It is hard to predict the effects of such factors when the environment and location of ultimate use are unknown. However, it is possible to reduce the influence by designing the detector coils. As skilled practitioners of the art know, there are many options for directional coil topologies and shielding.

The energizing power transmitter coils can cause the frequency to change. The transmitter coils 412 in the current example oscillate at a frequency that is well-understood by those who are skilled in the art. This frequency ranges from about 100 kHz up to around 120 kHz. The oscillation of the transmission coils can affect the oscillation of the detection coil(s), resulting in a deviation of approximately 10% in the detection readings (see FIG. 5(C)). When setting the coarse detection threshold, it is important to consider the effects of charging coils or power transmission on the signal.

“The effect of charging current drawn from the receiver(s), coupled to the transmitter, on the oscillation frequency is another factor that should be taken into account. The change in the?charge’ is what causes the draw current to change. The change in the?charge? of the battery or energy storage device is what causes the draw current to shift. This is also reflected in the power flow control that is used on the transmitter-side to adjust for the loss in power transmission efficiency. This phenomenon is especially noticeable over a longer time span. For example, the time it takes to charge a smartphone battery. The Buck converter voltage of the power regulation 440 represents the amount of power needed by the receiver. That amount of change is reflected back into the detection readings as fluctuating changes in the frequency oscillation (see FIG. 5(D)). The detection algorithm can account for this change in time by dynamically setting ‘baseline? The controller 420 can adjust the oscillation frequency to match the Buck converter voltage load. It will be obvious that the charging levels and power of the devices at any given time, as well as the type of devices charged, affect the oscillation frequency. These devices can also affect the detection measurements.

Combining these known influences on the magnetics of the detection coil(s), a robust and efficient detection regime can be created for the coarse (primary) detection regime. A set of thresholds can either be pre-set or dynamically determined during operation, depending on what mode it is. The multi-device charging system can be used to determine the use case. For example, no devices are being charged or powered, but one device of one type is being charged/powered, and one device from another type is being charged/powered. Two devices of the same type or different types are being powered/charged. For more precise categorization, it is possible to distinguish between positive and negative edges when the edges are being detected and counted. However, isolation of the thresholds for the negative and positive going edges can be useful. By detecting changes in the conditions at the transmitter, rather than measuring static values and thereby detecting an object once, it is possible to determine if the object has been removed from the receiver device. The secondary detection of the object is not required again if it is detected.

“Another example is that the IPT field’s influence on the detection field can alternatively be accounted in hardware, rather than in the software described above. FIG. FIG. 20A shows an equivalent circuit to the perimeter coil (self-oscillating), as described in PCT Publication No. WO 2014/070026. This circuit allows metal to be placed within the?loop’. The circuit works by changing the inductance of coil L1 which causes a change in oscillation frequency. This is provided by the resonant circuits of capacitor C1 and inductor L1 which are measured using the comparator circuitry. As mentioned above, the IPT field can cause the loop coil of power transmission coils to become coupled with the IPT fields, which can corrupt the detection signal. You can reduce the negative effect of the IPT fields on the detector coil (i.e. noise), by fitting filters in the circuit. 20B. 20B This reduces the coupling between the IPT field and the L1-L2 inductors.

The object detection method is able to detect objects (including receiver devices) and can also be used to detect their absence. This is done by removing a receiver device from the charging surface or moving relative to it using the same threshold regime. This allows the transmitter to be controlled easily and provides low-power, safe operation.

The following describes the operation of the transmitter according to the invention. When power is applied to the transmitter, which is when it is turned on, no transmitter coils are powered. The detector coil(s), however, is powered according to the above-described regimen to detect whether an object (including a receiver device) is within the charging range of its transmitter. The transmitter’s power supply is sufficient to enable object detection. When the transmitter is turned off, it stops.

“Upon detection, the system detects a proximate object and performs the detection of receivers in conjunction the controller. This is called a?fine? This?fine? detection is a scan of the transmitter?pad? The transmitter?pad is used to scan the object for any charging surface. To determine if an object is in one of the known, discrete positions of the array’s transmitter coils, this scan is performed by activating them selectively. As discussed previously, the objects detected may be receiver devices and other metal objects. The interaction of the metal and the energy transmitted from the transmitter coils facilitates detection. The transmitter coils are activated in such a way that the energy transmitted can cause the coupling of transmitter coils with proximate coils. This is done without powering/charging the receiver circuitry/load associated to the coupled receiver coils. The object detector uses magnetic interactions to determine the location of potential objects. The configuration of the transmitter coil array can affect the way that scanning and detection are carried out. The principles for inrush current measurement are described in PCT Publication No. WO 2013/165261, and PCT Publication Number. WO 2014/070026 and PCT Publication No. The basis for the steps or tests of the ‘fine? detection method can be used in WO 2013/165261. The present invention provides a detection method. You can also use other methods to locate the receivers, such as the one described later.

“As disclosed by PCT Publication Number. WO 2013/165261, and PCT Publication Number. WO 2014/070026 The inrush and frequency sweep detection techniques can be used to?identify’ the receiver devices. If the characteristics of the receiver electronics are known, it is possible to locate and identify the receiver devices. An alternative method for locating and identifying receivers will be discussed later. This helps to determine if the object detected is compatible with the transmitter’s power/charging. This function is what distinguishes the present invention from other systems for wireless powercharging consumer electronic devices.

“The transmitter can power up to two receivers of the same type or different types. These receiver types? These receiver types include all types of device, including smartphone, tablet, and power rating types such as 3 Watts, 10, etc. but also include types that are compliant with Industry Standards. These specifications are important to ensure backward compatibility in the event that the Industry Standards’ specifications change. Devices that conform to an earlier specification may not (fully) comply with a later specification. The Standard supports the charging and powering of older version devices using transmitters that are compatible with newer versions. This ensures that early adopters aren’t prejudiced until they can phase out the older version devices. While this is sensible, it may be problematic for different versions of the Standard-based specifications to be compatible or complementary in terms of circuit design or operation. The wireless power industry for consumer devices currently has multiple specifications, which are being set by different Standard Setting Organizations. Because of the different technology used for wireless power transfer, these competing specifications can make it difficult to support a single system.

“In this context the system of invention provides a mechanism to identify the?type? The system of the present invention allows for the identification of the?type? of receiver device, or at least the characteristics of the receiver device, and supports the charging of multiple?types? This identification allows the receiver device to be identified. The present invention provides a method by which the receiver device can identify itself to a transmitter. This is regardless of whether the transmitter is part the present system or one that conforms to an Industry Standard specification.

“As an example of the multi-device type charging and powering capabilities of this system, operation of FIG. 330’s communications module 330 is shown. Now, we will describe the operation of the communications module 330 in FIG. 3. This exemplary embodiment complies with the communication specifications set forth in a first edition of an Industry Standards specification. It allows identification, communications, and powering/charging to be performed with both receiver devices that are compliant with that version specification (where the second version is older than the first). The transmitter 302 must distinguish between different receiver types in order to select the appropriate wireless power transfer mode.

“The older version specification includes the following four phases of power transfer from transmitter to receiver:

“The transmitter monitors the surface of the transmitter (interface), for placement and removal. The system moves to the Ping phase if it detects an object.

“The transmitter sends out a digital ping and waits for a response. The system moves to the Identification & Configuration phase if it receives a response.

“The transmitter will identify the receiver and collect configuration information, such as the maximum power the receiver is willing to output (load). After the receiver has been identified and configured, the Power Transfer phase begins.

“The transmitter supplies power to the receiver and adjusts its coil current to respond to control data it receives from that receiver.”

“In the earlier version specification, a transition between any of the phases to the Selection phase requires that the transmitter removes the power signal from the receiver. These phases are described in the present invention as follows. The Selection phase is the object detection that the system of present invention performs as described previously. As will be explained, the Ping and Identification & Configuration phases are carried out in accordance with the present invention. The Power Transfer phase depends on which version of the receiver is being used. In this mode the transmitter adjusts power transfer as described above. In later version mode the receiver adjusts power delivery to receiver-side loads as described later. The earlier version specification will be referred as version A and the later version specification will be referred as version B in the following description. It should be noted that other versions and versions of different Standards specifications can be supported in the same way.

“First, we will describe the Ping phase. The present embodiment uses the version B transmitter (e.g. the transmitter 302) to conduct the receiver location scan. It selects which transmitter coils 312 are being powered in order to determine if there is a version A receiver or B receiver. If not, the scan is stopped. This is just an example. The various versions can be located later (e.g. in order) rather than within the same scan.

A communications protocol can be used between the transmitter(s) and the receiver(s), to identify the receiver device and detect the location of a receiver device on the transmitter surface. The communications protocol can be in accordance to either version specification. This allows version A and B devices to be identified in a quick manner. It is important that the system works quickly so that users don’t have to wait for the receiver devices to be identified before they can be powered/charged by it. FIG. FIG. 6. Describes the components of an exemplary data or communications packet. Version A communications protocol. A bit stream is a packet that is made up of ONE or ZERO bits. FIGS. FIGS. 6(A) & 6(B) show that a ZERO bit encodes a single transition within a clock signal’s single period, tCLK, while a ONE bit encodes two transitions in a single clock interval, the clock period being approximately 2 kHz. It doesn’t matter if the bit is encoded with one or two transitions; it only matters how many transitions occur within the time period. Each packet byte is encoded as an 11-bit asynchronous Serial format. This includes one start bit, one odd Parity bit, and one stop bit. 6(C). FIG. FIG. 6(D) shows the packet with four parts (portions/fields). A preamble of 11-25 bits with all bits set at ONE; a header portion (a single byte) which indicates the type of packet and the number of message portions bytes; a message section of one or more bits; and a checksum (a single byte) calculated as the header byte XORd and each message portion bytes.

“In operation, a?ping? The?ping? is transmitted sequentially by the transmitter 302 to each transmitter coil 312 in the array 314 over a predetermined time period. The ‘ping? The?ping? is a discrete, non-charging energy signal that is capable of temporarily coupling the transmitter coil transmitting a ping with the receiver coil. The transmitted power conditioner 322 is controlled to produce the correct power signal for the time period through the transmitter coils 312 and selector 324. The temporary ping signal provides power to the receiver device that allows it to “send?” The transmitter 302 can send a coupling communication packet. The communications module 330 of transmitter 302 also includes processing circuitry to decode and process the received packets. These functions can be performed by the circuitry in the communications module 332 of the transmitter 302, or as an integral part of controller 320. How the receivers encode and send the information in packets is described later. is described later.”

“FIG. “FIG. Also shown is a timer 706, which measures the time between received packets. The decoder 702 will only consider a packet of received messages valid if at least four preamble bits have been received, the checksum matches the protocol version A, but other valid criteria are possible. The state machine 704 receives the decoded messages. It also indicates when an error message has been received. The state machine 704 process the decoded packets.

“As mentioned above, a receiver device that receives the energy from the ping signal sends a coupling communication packet to the transmitter. The signal strength packet is the first form of this coupling packet. The signal strength packet transmits a signal strength value within the packet’s message section. This indicates the degree to which the transmitter coil sends the ping and the receiver coil that is coupled. The state machine 704 receives this signal strength packet and locates the receiver device at a location local to the transmitting coil. This is because the transmission coil that received the signal strength packet is the one which is receiving the signal strength packet. It is the IPT field reflected signal, which is what skilled artists understand.

The signal strength packet can be used to determine the transmitter coil(s) for charging/powering the receiver device. As discussed in detail below, the receiver can measure the coupling between one or more transmitter coils and the receiver coil(s). The signal strength is used to communicate this information to the transmitter. The transmitter can then determine which combination of transmitter coils or transmitter coils provides the best coupling. If a combination of several transmitter coils is to be used to maximize power transmission while optimizing power efficiency, the transmitter 320 can determine which transmitter coil 312 gives the highest signal strength measurement. The controller 320 also may determine which transmitter coils 312 are adjacent to that transmitter coil. transmitter coil 312 is the next ‘best? The transmitter coil 312 provides the next?best? signal strength. Two transmitter coils 312 can be selected for power transmission by using the selector 324. You can also use other measurements, including the current inrush method, discussed earlier.

“A two-stage receiver detection method has been described, in which objects are detected first using a low power coarse detection method, and then located relative the transmitter coils by fine detection scanning method. However, the present invention covers a single-stage detection method. If the power efficiency of detecting new objects or the movement of previously present receiver devices is less important for a particular application, then the coarse detection can either be omitted in certain situations or the object detection circuitry, and associated software, completely from the system. The circuitry of the receiver and transmitter may be optimized for power efficiency during the transmitter pad scan. Any increase in detection speed/location may be more important than the need to have a low-power idle? “Standby” modes.

The system enters the Identification and Configuration phase after it has located the receiver device. The transmitter locates the receiver device and collects configuration information, such as the receiver’s maximum power (load) at its output. This is done by the receiver device being located sending an identification communication packet to the transmitter after the energy of the signal has been received. The identification (second) communication packet conveys the identity of the receiver device within the message portion. The message may contain a Version Code and a Manufacturer Code. According to the version A communications protocol, the Version Code identifies the receiver as version A or version B compatible. The Manufacturer Code identifies receiver’s manufacturer. The Basic Device Identifier is the identity of the receiver. This can be generated randomly to ensure sufficient uniqueness (e.g. device ID or ID Code). This received identification packet is processed by the state machine 704, which allows the transmitter 302 to locate the receiver device. The version A communications protocol includes a configuration (third-party) communications packet. This packet contains the message portion that indicates the maximum power the receiver can receive. This configuration packet is processed by the state machine 704 and the Power Transfer mode parameters are set accordingly by the transmitter 302. The configuration packet for a version B receiver may include additional information such as the maximum/minimum number transmitter coils required to power it.

“An alternative to the protocol described above of sequentially providing the identification, coupling and configuration packets in reply to the ping from transmitter, the system can be configured to send the same information in more data packets. FIG. FIG. 6(E), illustrates an alternate packet structure that includes an ID portion or field between the message and header portions. This allows for the identification of the device (such as the Basic Device Identifier) to be included in all data packets that may be useful during future communications. This could eliminate the need to send a separate identification data packet. If the ID Code can be deduced from the Version and Manufacturer Codes, it can speed up the identification scan and location. The ID code could also be used to identify the initial configuration requirements of the identified receiver devices. This could allow for the configuration data packet to be omitted, which could further speed up the processing of the fine? The present system detects the method.

“In order to explain the Power Transfer phase, we will first describe in detail the receiver devices(s) that are applicable to the invention with respect to the applicable transmitter(s).

Summary for “System and Method for Power Transfer”