WO2023094974A1 - Station de charge à positionnement libre pour dispositifs électroniques et procédé - Google Patents

Station de charge à positionnement libre pour dispositifs électroniques et procédé Download PDF

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Publication number
WO2023094974A1
WO2023094974A1 PCT/IB2022/061239 IB2022061239W WO2023094974A1 WO 2023094974 A1 WO2023094974 A1 WO 2023094974A1 IB 2022061239 W IB2022061239 W IB 2022061239W WO 2023094974 A1 WO2023094974 A1 WO 2023094974A1
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WIPO (PCT)
Prior art keywords
smart device
pixels
platform
charging station
charging
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PCT/IB2022/061239
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English (en)
Inventor
Shehab Ahmed
Moutazbellah KHATER
Tarek Mahmoud Atia MOSTAFA
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King Abdullah University Of Science And Technology
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Application filed by King Abdullah University Of Science And Technology filed Critical King Abdullah University Of Science And Technology
Publication of WO2023094974A1 publication Critical patent/WO2023094974A1/fr

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Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J50/00—Circuit arrangements or systems for wireless supply or distribution of electric power
    • H02J50/05—Circuit arrangements or systems for wireless supply or distribution of electric power using capacitive coupling
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J50/00—Circuit arrangements or systems for wireless supply or distribution of electric power
    • H02J50/005—Mechanical details of housing or structure aiming to accommodate the power transfer means, e.g. mechanical integration of coils, antennas or transducers into emitting or receiving devices
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J50/00—Circuit arrangements or systems for wireless supply or distribution of electric power
    • H02J50/40—Circuit arrangements or systems for wireless supply or distribution of electric power using two or more transmitting or receiving devices
    • H02J50/402—Circuit arrangements or systems for wireless supply or distribution of electric power using two or more transmitting or receiving devices the two or more transmitting or the two or more receiving devices being integrated in the same unit, e.g. power mats with several coils or antennas with several sub-antennas
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J50/00—Circuit arrangements or systems for wireless supply or distribution of electric power
    • H02J50/90—Circuit arrangements or systems for wireless supply or distribution of electric power involving detection or optimisation of position, e.g. alignment

Definitions

  • Embodiments of the subject matter disclosed herein generally relate to a charging station and method for wireless power transfer between a platform of the charging station and a mobile device using a capacitive power transfer (CPT) mechanism, and more particularly, to a free positioning charging platform that uses the CPT mechanism and imposes no positioning restriction on the device to be charged by detecting the location of the device, and activating only corresponding pixels of the platform for the energy transfer.
  • CPT capacitive power transfer
  • I PT inductive power transfer
  • UAV Unmanned Aerial Vehicle
  • IPT has clear limitations because of the high eddy current losses to the surroundings, especially with metals, high standing losses, and complicated design, requiring bulky and expensive magnetic materials and electromagnetic interference (EMI) shielding solutions.
  • the CPT approach is a technology that uses a varying electric field (not magnetic field) to transfer power, and it has been introduced as a good alternative to the IPT approach for near field power transfer applications due to its unique features, such as design flexibility of coupling structure, ability to transfer power across electrically isolated metal barriers, low standing losses and EMI, and low cost and weight [2],
  • a charging station for capacitive power transfer to a smart device
  • the charging station includes a capacitive power transfer, CPT, module configured to transfer electrical energy to the smart device through a platform, a detection module configured to detect a location of the smart device on the platform, and a controller configured to coordinate the CPT module and the detection module so that a resonant frequency is implemented between the charging station and the smart device.
  • the platform includes an array of pixels Py, and a first set of pixels Pij of the array of pixels Py is provided with a positive polarity and a second set of pixels of the array of pixels Py is provided with a negative polarity, depending on the location of the smart device on the platform.
  • a smart device for receiving electrical energy from a charging station, and the smart device includes metal plates configured to form a capacitor with corresponding metal plates of the charging station, a compensation circuit electrically connected to the metal plates and configured to change an impedance of the metal plates to implement a resonant frequency with the charging station, a rectifier connected to the compensation circuit and configured to change an AC current to a DC current, a DC to DC converter connected to the rectifier and configured to change a voltage level of a DC voltage, and electronics associated with the smart device, where the electrical energy flows from the charging station to the electronics through two capacitors formed with the metal plates.
  • a charging system for transferring electrical energy from a charging platform to a smart device
  • the charging system includes the charging platform and the smart device.
  • the charging platform includes a capacitive power transfer, CPT, module configured to transfer the electrical energy to the smart device through a platform, a detection module configured to detect a location of the smart device on the platform, and a controller configured to coordinate the CPT module and the detection module so that a resonant frequency is implemented between the charging station and the smart device.
  • the platform includes an array of pixels Py, and a first set of pixels P of the array of pixels Py is provided with a positive polarity and a second set of pixels of the array of pixels Py is provided with a negative polarity, depending on the location of the smart device on the platform.
  • the method includes placing the smart device on a platform of the charging station, wherein the platform includes an array of pixels Py, measuring with a detection module of the charging platform a voltage phase and a current phase of a voltage and a current supplied to a coil of each pixel of the array of pixels Py, determining a location of the smart device on the platform based on a difference between the measured voltage phase and current phase of the pixels, identifying a set of active pixels as those pixels that correspond to the location of the smart device, providing a first polarity to a first set of pixels of the set of active pixels, where the first set of pixels corresponds to a first plate of the smart device, and providing a second polarity to a second set of pixels of the set of active pixels, wherein the second set of pixels corresponds to a second plate of the smart device.
  • Figure 1 A is a schematic diagram of a novel charging station that uses CPT for charging a smart device
  • Figure 1 B is a schematic diagram of a CPT module and a determination module of the charging station of Figure 1 A;
  • Figure 1 C is a schematic diagram of the smart device charged in
  • Figures 2A to 2D illustrate compensation networks that may be used by the charging station of Figure 1 A;
  • Figures 3A and 3B illustrate adjustable capacitor and inductor structures, respectively, that may be used with compensation networks in the charging station of Figure 1A;
  • Figures 4A and 4B illustrate alternative adjustable capacitor and inductor structures, respectively, that may be used with compensation networks in the charging station of Figure 1 A;
  • Figure 5A illustrates a structure of a platform of the charging station of Figure 1 A
  • Figures 5B and 5C illustrate a structure of a pixel of the platform having an inductive sensing
  • Figure 5D illustrates a structure of the pixel having a capacitive sensing
  • Figure 6 illustrates an alternative structure of the platform of the charging station of Figure 1A
  • Figure 7 illustrates a structure of a pixel of the platform shown in Figure 5A;
  • Figures 8A and 8B illustrate a first implementation of the charging station of Figure 1 A
  • Figure 8C shows a second implementation of the charging station
  • Figure 8D shows a third implementation of the charging station
  • Figure 9 illustrates a boundary determined on the platform, by the charging station, around the smart device, when the smart device is placed on the platform;
  • Figures 10A and 10B illustrate the phase between the current and voltage of a coil located around a pixel of the platform of the charging station; and [0027] Figure 11 is a flow chart of a method for transferring capacitive power from the charging station to the smart device.
  • first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another.
  • a first object or step could be termed a second object or step, and, similarly, a second object or step could be termed a first object or step, without departing from the scope of the present disclosure.
  • the first object or step, and the second object or step are both, objects or steps, respectively, but they are not to be considered the same object or step.
  • a novel CPT-based charging station which has one or more of the advantages of: large area, low cost, the ability to simultaneously charge several devices with different power needs, and the charged devices can be freely placed anywhere on the charging platform, with no specific orientation.
  • the primary side of the station, or, in other words, the platform is constructed by an array of small space-controlled pixels, which will allow a controller to automatically detect the smart device' location relative to the platform, and to energize only those pixels that correspond to the location of the smart device.
  • the term “pixel” is used in this application to mean a single element of the platform, which can be in the mm 2 or cm 2 range, and two such pixels may be enough for charging the battery of a smart device through the CPT approach.
  • a pixel in this application is very different from the notion of a pixel of a monitor or screen.
  • FIG. 1 A there is a charging station 100 and a smart device 190 that needs to be electrically charged though CPT from the charging station 100, along an electrical field link 100-190.
  • the charging station 100 includes a first subsystem 110, also called the CPT subsystem or module, which effectively transforms an input electrical current into a current that is appropriate for the CPT approach and also transfers the power associated with this current to the smart device 190 through the link 100-190.
  • the CPT subsystem has plural components, which are discussed later in greater detail.
  • a controller 160 for example, a processor, is configured to regulate the CPT subsystem 110, as also discussed later.
  • a second subsystem 170 also called the detection subsystem or module, which may be located in the same housing 102 as the first subsystem 110, is configured to detect a position of the smart device 190 and its orientation relative to a platform 124, and to provide this information to the controller 160, and implicitly to the CPT subsystem 110 for effectively charging the smart device 190. While power is mainly exchanged among the various modules of the CPT subsystem, signals/commands are exchanged between the controller 160 and the various modules of the detection subsystem 170, which are discussed later in more detail.
  • the electric field link 100-190 does not include a magnetic field, only an electrical field, and extends between the platform 126 of the charging station 100 and corresponding plates 192 of the smart device 190.
  • Figure 1 B shows the CPT subsystem 110 including a power grid connector 112, which is configured to receive AC energy from the power grid.
  • the connector 112 may be configured to also receive DC current.
  • the power grid connector 112 is electrically connected to an AC/DC converter 114, which is used to convert the AC current 113 from the grid to a DC current 115.
  • the converter 114 may include half or full-wave diode rectifiers. If a higher efficiency is desired, then synchronous FET rectifiers may be used instead of the diodes.
  • the converter 114 is electrically connected through a connector to a DC/DC converter 116.
  • the converter 116 may be a buck, boost or buck-boost type converter for adjusting a level of the DC voltage 115 that is going to be supplied to the smart device 190. Note that the DC/DC converter 116 is controlled by the controller 160, as a corresponding control link 161 is present between the controller and the converter.
  • the DC/DC converter 116 is electrically connected, through an electrical link, to a high-frequency inverter 118, which converts the DC voltage/current 117 to a high-frequency AC signal 119.
  • a high-frequency inverter 118 converts the DC voltage/current 117 to a high-frequency AC signal 119.
  • Different topologies have been used in the past for this step, depending on the needed power level and the targeted operating frequency such. Some of these topologies include current-fed push-pull power converters, single-ended class E power converters, and voltage-fed half-bridge (full bridge) converters.
  • the high-frequency inverter 118 is driven by a gate drive 120, which is controlled by the controller 160 through a control link 162.
  • the AC signal 119 is supplied to a primary side compensation circuit 122, which is configured to provide voltage gain and compensation functionalities.
  • the primary compensation circuit 122 is provided in the charging station 100 and a secondary compensation circuit 194 (to be discussed later) is provided in the smart device 190. These two circuits may be used for matching, compensation, and/or voltage boosting.
  • the primary compensation circuit 122 is controlled by the controller 160 along a control link 163. [0037]
  • the compensation circuits (primary and secondary) are used as the charging station’s impedance is not the same as the smart device’s impedance.
  • the compensation circuits have the objective to match the impedance of the charging station to the impedance of the smart device no matter which smart device is used.
  • a maximum power transfer from a source (charging station) to a load (impedance of the smart device) takes place when both their impedances are equal.
  • the equivalent capacitance of each of the charging station 100 and the smart device 190 is small, in the range of a few tens to hundreds of picofarads and thus, to deliver large amounts of power, a larger resistance R must be used or a high frequency.
  • the large resistance R is undesired because it wastes energy, the high-frequency approach is selected, and the high-frequency is generated by the high-frequency inverter 118.
  • high-frequencies operations like in the GHz range, are very challenging to control.
  • the capacitive reactance represented by the capacitive interface between the charging station 100 and the smart device 190 generates a frequency dependent impedance, which means that the real power P transferred between the two systems is also frequency dependent and the ratio between P and the apparent power S, which is the power gain (or loss in this case) of the circuit will be also frequency dependent.
  • the power gain of such an LCR circuit is given by:
  • the gain peak for such a configuration can be achieved at a lower frequency than when using only capacitors and the frequency at which the gain peak is achieved is the resonant frequency, which is defined by:
  • the circuit quality factor Q is a measure of the selectivity of the resonant circuit. The higher the quality factor, the narrower its bandwidth and the higher the selectivity of a resonant circuit.
  • the quality factor Q for the LCR system is given by
  • the coupling interface between the charging station and the smart device has a small value which results in a high Q and consequently, the tuning is challenging, and the system is highly sensitive to coupling variation and load change.
  • the compensation network 122 may be used for the compensation network 122 to achieve the resonant frequency between the charging station and the smart device, and these networks include, but are not limited to, a series inductor network 200 as shown in Figure 2A, LCC network 210 as shown in Figure 2B, LCL-LC network 220 as shown in Figure 2C, double transformers network 230 as shown in Figure 2D, double LC network (not shown), double LCLC network (not shown), Z network (not shown), etc.
  • a capacitor bank 310 as shown in Figure 3A or an inductor bank 320 as shown in Figure 3B as the compensation network 122.
  • Each bank may include plural switches 312, 322, which are associated with individual capacitors 314 and inductors 324, respectively and thus, by controlling which switch is closed or open, a desired number of capacitors or inductors can be selected to match the impedances of the charging station and the smart device.
  • Compensation circuits that include switch-controlled capacitors and/or switch-controlled inductors to construct variable capacitors and variable inductors as illustrated in Figures 4A and 4B.
  • Figure 4A shows a switch-controlled capacitor circuit 400 (also called a variable circuit herein)
  • Figure 4B shows a switch-controlled inductor circuit 450 (also called a variable inductor herein).
  • Each circuit includes two transistors Sscm and Sscc2, and corresponding diodes Di and D2.
  • the circuit 400 also includes a capacitor C a .
  • the inductor-based switch circuit 450 further includes an inductor L s , forming the configuration 454. If the circuit 454 is modified to also have the capacitor Ca, then the switch-controlled capacitor in series with an inductor circuit 452 is obtained, as also shown in Figure 4B.
  • the current or voltage signal 123 from the primary compensation circuit 122 is supplied to a primary commutation circuit 124, which is configured to secure freedom in orientation and positioning of the load devices (i.e., smart device) relative to the platform 126.
  • a current 125 from the commutation circuit 124 is supplied to the platform 126, which is the actual piece of hardware that physically receives the smart device 190 for CPT charging.
  • the platform 126 is schematically illustrated in Figure 5A as having an n x m matrix of pixels Pij. The pixels shown in Figure 5A are hexagonal.
  • Every single pixel Pij includes a metal plate 510 (the first plate of the capacitor formed with the smart device) fully surrounded by a planar detection unit, e.g., a coil 520, as shown in Figure 5B or a solid plate 521 as shown in Figure 5D.
  • the pixels or at least the metal plates 510 are covered with a dielectric material 512, as shown in Figure 5C, so that when the smart device 190 is placed directly on top of the metal plate 510, a capacitor is formed between the metal plate 510 (first plate) and a corresponding metal plate 192-1 (second plate) in the smart device 190.
  • the corresponding metal plates 192-1 or 192-2 in the smart device 190 are shown in Figures 8A and 8B.
  • both the metal plate 510 and the planar coil 520 extend in the same plane X-Y, as shown in Figure 5C.
  • the planar coil 520 may include any number of turns formed on a substrate, for example, a printed circuit board 522. No part of the planar coil 520 touches the metal plate 510, they are mechanically and electrically separated from each other.
  • the coil 520 is part of the load device detection subsystem 170, which is discussed later in more detail.
  • Plural metal plates 510 will couple with the secondary side plates 190 (to be discussed later) of the smart device 190, and accordingly, the capacitive interface is formed between plates 510 and 190, allowing the wireless capacitive power transfer.
  • the size of the pixels is optimized based on the total area of the charging platform 126, the size of the receiving side plates 190 of the smart device, and the number of smart devices to be powered.
  • a size of the platform 126 can be in the centimeter (cm) or tens of cm range while a size of a pixel is in the mm to cm range.
  • the pixel Pij may be implemented as the plate 510 and a sensing solid plate 521 which encircles the plate 510.
  • the sensing solid plate 521 may have form, similar to the plate 510. This implementation of the pixel is preferred for the case that capacitive sensing is implemented for load device detection.
  • the platform 126 has a single layer of metal plates 510 in the embodiment shown in Figure 5A. However, such an arrangement may require complicated electronics for switching the plates to be positive or negative, depending on the location of the smart device and its plates 190.
  • the embodiment illustrated in Figure 6 shows the platform 126 having the metal plates distributed on two different and parallel planes, a first plane 610 defined by axes X and Y, and a second plane 612 defined by axes X’ and Y’, which are parallel to axes X and Y, respectively.
  • the first plane 610 includes metal plates 510
  • the second plane 612 includes metal plates 510’.
  • the two planes are separated from each other along a Z direction, which is perpendicular to each of X and Y.
  • the planar coil 520 may be distributed on different, plural, parallel planes, around each metal plate 510, as shown in Figure 7.
  • plural planar coils 520-j are placed around a single metal plate 510, where j may be from 1 to 10.
  • a first planar coil 520-1 is located in the same plane as the metal plate 510, and all other planar coils are above and/or below the first planar coil.
  • the embodiment of Figure 7 shows all the other planar coils being located below the first planar coil. In this embodiment, all planar coils are electrically connected in series to each other.
  • the commutation circuit 124 ensures that each metal plate 510 in the charging platform 126 (see discussion above with regard to Figures 5A and 5B) has the flexibility to be either connected to a positive or a negative signal (the terms “positive” and “negative” are used herein interchangeably with the terms “hot” and “ground” as only an AC current is present at this point in the circuit). Thus, the commutation circuit is configured to commute/change these polarizations as necessary. The commutation decision is made by the controller 160, which instructs accordingly the commutation circuit 124, along a control link 164. A desired implementation of this circuit is discussed later.
  • the commutation circuit 124 includes, in one embodiment, two switches for each metal plate 510.
  • One switch is connected to the positive or hot output of the compensation circuit 124 and the other is connected to the negative or ground output.
  • PCB printed circuit board
  • back-to-back FETs and relays would be more suitable.
  • the issue with using back-to-back FETs for this setup is the high number of FETs needed, as four FETs will be used for each plate.
  • two cascaded PCB layers 610 and 612 that include metal plates 510 and 510’, respectively, are used in the platform 126 (see Figure 6).
  • the metal plates 510 of the platform 126 receive an AC signal 125 from the commutation circuit 124, which is either positive or negative (hot or ground), depending on which plate 192 of the smart device 190 is present.
  • One of these signals is applied to a first set of metal plates and the other is applied to second set of metal plates.
  • the reunion of the first and second sets are part of an array of pixels that correspond to the smart device 190, as discussed later.
  • All metal plates 510 on the top layer 610 if the configuration shown in Figure 6 is selected, will be connected to the positive signal through single FET switches while the bottom plates 510’ will be connected to the ground through FET single switches.
  • the activated plates from the bottom layer 612 (the second set) will not be affected by the above-inactivated plates from the top layer 610 as the first set of metal plates are offset from the second set.
  • the detection subsystem 170 is supplied with power from the AC/DC converter 114 of the CPT subsystem 110.
  • a buck DC/DC converter 172 is used to step down the input voltage received from the converter 114.
  • the buck converter 172 is controlled by the controller 160 along a control link 165.
  • the stepped down voltage 173 is supplied by the buck converter 172 to a DC/AC inverter 174, which is configured to operate in this embodiment at 100 kHz (another frequency may also be used), to enable a current flow 175 through a detection resonant circuit 178.
  • the DC/AC inverter 174 is controlled by the controller 160 through a gate drive 176 and a dedicated control link 164.
  • the voltage and current detection circuit 178 includes a voltage phase estimator 179 and a current phase estimator 180.
  • the current phase estimator is configured to estimate the phase of the current running in a detection resonant circuit 182, which includes a compensation capacitor and the detection coil 520 (discussed above with regard to Figure 5).
  • the voltage phase estimator 179 is configured to estimate the phase of the square wave voltage signal 175 generated by the inverter 174.
  • the readings from the voltage and current detection circuit 178 are supplied to the controller 160, along links 165.
  • the compensation circuit 182 is configured to adjust an impedance of the detection coil 520 to achieve a resonant frequency. Accordingly, by fully compensating the detection coil 520 at the resonant frequency (f), the phase difference between the input voltage and input current should be zero (unity power factor). Many compensation topologies were proposed; however, not all have the same characteristics. In this embodiment, a series compensation capacitor (see element 400 in Figure 4A; however the compensator 452 in Figure 4B can also be used) is used for its advantage of simplicity and effectiveness. The compensation capacitor (C) value can be calculated using
  • a signal 183 from the compensation circuit 182 is provided to the coil
  • the coils’ commutation circuit 184 allow the square wave voltage signals 175 generated by the half-bridge inverter 174 to be directed to any connected detection coil 520.
  • Back-to-back MOS switches or relays are connected to every detection coil 520, and they act as switches, which allow the current to flow into whichever switch is activated.
  • the commutation circuit 184 is controlled by the controller 160 along a control link 166.
  • the system shown includes, in addition to the charging station 100, a smart device 190.
  • the smart device 190 is schematically illustrated in Figure 1 C, and includes the secondary side plates 192 (i.e., the second metal plate of the capacitor formed between the platform 126 and the smart device 190).
  • the secondary side plates 192 include only two metal plates (192-1 and 192-2) having any shape and/or size.
  • the secondary side plates 192 are connected to the secondary compensation circuit 194, which perform similar functions, and have a similar structure, as the primary compensation circuit 122. Thus, their detailed description is omitted herein.
  • the secondary compensation circuit 194 is connected to a high-frequency inverter 196, which is used to convert the high-frequency AC signal received along the electric field link 100-190, into a more usable DC-voltage signal.
  • the rectifier 196 is necessary if DC power rather than AC power is supplied to the load.
  • a DC/DC converter 198 is connected to the rectifier 196 and is configured to convert the output from the rectifier to a stable DC voltage of 5 V, 12V, etc., which is more suitable for powering or charging the electronics 199 of the smart device 190.
  • a controlled boost-buck DC-DC converter can be used to provide an optimal equivalent load resistance.
  • the electronics 199 in Figure 1C schematically stands for all the electronics associated with the smart device, be it a drone, cell, laptop, etc.
  • the electronics 199 may include a combination of transistors, resistors, capacitors and/or inductors.
  • the controller 160 is configured to perform at least one of the following functions: generate signals for gate drives for DC/DC converters and DC/AC inverters, receive and analyze the phase of the current and voltage from the detection subsystem 178, adjust the compensation circuit 122 for the CPT subsystem 110, and/or control the commutation circuits 124 and 184.
  • a field-programable gate array supports concurrent logic operations through the use of multiple interconnected logic cells.
  • FPGAs are generally used for applications consisting of multiple logical operations and are especially useful for interfacing, manipulating, and controlling multiple logic signals.
  • the CPT-based charging station discussed above consists of various clock signals, pulse width modulation (PWM) signals, clocked data signals and addressing signals requiring precise timings.
  • PWM pulse width modulation
  • Most of the operations performed in the controller are relatively simple. They consist of certain input signals, like clock signals and analog to digital converter, ADC, data signals, manipulating them through simple operations, and generating appropriate output signals like PWM- and addressing signals.
  • the FPGA controller or raspberry pi would be appropriate for the proposed station.
  • a second possible way, which is the most preferred to be used for the detection of the smart device on the platform 126, which is simpler and more cost effective, is by using proximity sensing either inductive or capacitive next to the metal plates 510.
  • the pixel shown in Figure 5B may be used, while for capacitive sensing, the pixel shown in Figure 5D may be used.
  • the detection coils 520 will be connected to an inductance to digital converters (LDC) such as the LDC1614 from Texas Instruments or PSoC 4 MagSense Inductive Sensing from Infinion.
  • LDC inductance to digital converters
  • the detection coils 520 will be changed to solid electrodes surrounding the pixels Pij and connected to capacitance to digital converters such as the FDC1004 from Texas Instruments or PSoC 4 and PSoC 6 MCU CAPSENSE from Infinion.
  • capacitance to digital converters such as the FDC1004 from Texas Instruments or PSoC 4 and PSoC 6 MCU CAPSENSE from Infinion.
  • Another possible method is to attach a grid or ultrasound sensors under the pixels Py and then to connect them to a microcontroller such as MSP430FR6047 Ultrasonic
  • FIG. 8A shows a first implementation in which two smart devices 190-1 and 190-2 are being placed in capacitive connection with the charging station 100 through the platform 126.
  • each smart device has two plates 190-1 and 190-2, that form the secondary side plates 192.
  • each smart device needs to capacitively connect to two sets of plates 510 (the first set 126-1 and the second set 126-2) for CPT charging.
  • any of the sets 126-1 or 126-2 of plates 510 may include plural pixels Py, or metal plates 510, depending on the size of the plates 192-1 and 192-2, or the size of the smart device 190.
  • the charging station 100 can be configured to detect (using the detection subsystem 170) the location (boundaries 910) of the entire smart device 190 on the platform 126, as illustrated in Figure 9, and to activate only those pixels Pij (of the entire array of pixels 900) that are within the boundary 910. More specifically, as the plates 192 of the smart device 190 change the impedance of the pixels from the sets 126-1 and 126-2, which are associated with the plates 192-1 and 192-2, respectively, the detection circuit of the charging station determines the pixels associated with the sets 126-1 and 126-2.
  • the detection subsystem 170 is capable of determining (as discussed later) which of the plates 192-1 and 192-2 needs to be positive and which negative, and thus, using the commutation circuit 124, activates the first set 126-1 of pixels Py to be negative (or ground) and the second set 126-2 of pixels to be positive (or hot), to match the plates 192-1 and 192- 2 of the smart device 190.
  • the selection of which set to be positive and which set to be negative can be randomly made as it is irrelevant which of the plates 192 is positive and which is negative.
  • each set 126-1 and 126-2 of pixels includes a number of pixels that corresponds to the size of the plates 192-1 and 192-2 of the smart device 190, i.e., although the smart device includes only two plates, each of the first and second sets 126-1 and 126-2 may include plural metal plates 510, i.e., plural pixels.
  • the first set 126-1 and the second set 126-2 are part of the array of pixels 900.
  • the array 900 also includes all the pixels that correspond to the boundary 910.
  • the array 900 also includes the pixels that are outside the boundary 910.
  • the number of metal plates 510 in the array 900 is larger than the number of metal plates in the first and second sets.
  • a second smart device 190’ is present on the platform 126, as also shown in Figure 9, and for this case, there are additional first and second sets 126-T and 126- 2’ of pixels that correspond to the plates of the smart device and these sets of pixels are detected and activated similar to the sets 126-1 and 126-2.
  • FIGS. 8A and 8B show full-wave rectifiers being used for the AC/DC converters, a half-bridge is used for the DC/AC inverters, and buckboost and buck converters are used for the DC/DC converters in the CPT subsystem and detection subsystem, respectively.
  • a double-LC compensation circuit 122 is used in the CPT subsystem 1 10, while a series capacitor Ccomp is used for the detection subsystem 170’s resonant circuit 182. Based on the described example, the operation of the CPT-based charging station 100 is now discussed.
  • the full-wave rectifier 1 14 rectifies the input 113 from the grid 810 and the outputs 1 15 and 171 are fed to the buck-boost converter 116 of the CPT subsystem 110 and the buck converter 172 of the detection subsystem 170, respectively. Both converters 116 and 172 are controlled by tens of kHz PWM signals 161 , 165 generated by the controller 160. According to the duty cycle of the controlling PWM signals, the DC-voltage output 117, 173 from the DC/DC converters 116, 172 are thus adjustable.
  • the DC outputs 117, 173 from the converters are then converted to a square wave voltage signal 119 of 1 MHz for the CPT half-bridge 118 inverter and a voltage signal 175 of 100 kHz for the detection subsystem inverter 174.
  • a specialized high-frequency MOSFET driver circuit 120/176 drives each of the half-bridge inverters 118 and 174 while the control signal is fed from the controller 160.
  • the current phase, as well as the halfbridge output voltage phase are estimated using individual estimator circuits 180 and 179, respectively, which send the information back to the controller 160.
  • Figures 10A and 10B show the input voltage and current for the detection LC resonant circuit for a pixel Pij, with Figure 10A showing the phases if no smart device 190 is present above the pixel Pij and Figure 10B showing the phases if the smart device 190 is present next to the pixel Pij.
  • the differences between the phases of the current and voltage can be seen in Figure 10B.
  • the LC resonant circuit 182 is fully tuned for the case shown in Figure 10A, as no phase difference is observed.
  • the determination subsystem 170 is configured to measure this phase change and determine the presence of the smart device on the platform 126.
  • the controller 160 is configured to continuously scan and store the voltage and current phases when each detector coil 520 is connected.
  • the controller can store the relative info of each coil 520 by controlling the coil’s commutation circuit 184, and ensures that the switch 820-I (with I being an integer larger than 2), which is related to a corresponding coil 520-I, is turned on and its phases are measured and stored. Then the switch 820-I is turned off and another switch 820- 1’ of another coil 520-I’ will be turned on and the process will be repeated until all coils are investigated.
  • the controller 160 compares the phase change of each coil 520-I to a specific, previously adjusted value, which is measured when the coil is not in the presence of the smart device. Accordingly, the pixels Pij covered (close to) by the smart device 190 will have a disturbed phase, which is identified by the controller 160, and thus, the location and orientation of the smart device 190 is determined, i.e., the controller 160 identifies the sets 126-1 and 126-2 of metal plates 510 that are next to the smart device 190 based on their modified voltage and current phases, as illustrated in Figure 9. In one embodiment, it is possible to select a first threshold for the disturbed phase, which is associated with the presence of the smart device 190 next to the measured coil 520-I.
  • the first and second sets 126-1 and 126-2 of pixels may be selected to match the entire surface of the boundary 910 of the smart device, or only the entire surface of the secondary plates 192, as shown in Figure 9.
  • the controller 160 is configured to adjust the CPT compensation circuit 122 to allow maximum effectiveness for a specific load device(s), i.e., to switch on or off capacitors and/or inductors to achieve the resonance frequency discussed above with the smart device.
  • the controller 160 is configured to pick the most suitable values for the compensation circuit 122 as part of a controller algorithm is responsible for estimating the capacitive interface impedance value based on the number covered pixels.
  • the controller 160 is configured to draw the imaginary boundary 910 of the smart device 190, as shown in Figure 9, around the smart device 190, based on a previously programmed algorithm for each detected device. In other words, the boundary 190 is drawn based on the pixels of the platform 126 that have their current and voltage phases disturbed over a given threshold.
  • each metal plate 510-1 in the platform 126 is electrically connected to two switches 834-1 and 836-1 in the commutation circuit 124, one for the positive polarity 830 and another one for the negative polarity 832.
  • the commutation circuit 124 may be used for other circuits.
  • the corresponding switch 832-I or 834-I is closed, the power from the grid 810 is transferred to the smart device 190 through the electric field link 100-190.
  • the received signal is then rectified and adjusted to be suitable for the smart device’s electronics, e.g., charging.
  • the detection module 170 is simplified and includes plural inductance to digital converter (e.g., LDC1614 from Texas Instruments, USA) units 840-J, with J being equal to I or, with J being mapped to four values of I, i.e., each unit 840-J may be connected to four coils 520 of four different pixels.
  • a unit 840-J is directly connected, through an electrical link 842, to corresponding coils 520 in the platform 126.
  • the detection module 170 is simplified and includes plural capacitive sensing units 850-J, with each unit being connected to a single pixel of the first set 126-1 and a single pixel of the second set 126-2 discussed above.
  • the capacitive sensing unit may be a capacitive to digital converter FDC 2214 (Texas Instruments, USA) or a capacitive sensing unit CAPSENSE (Infineon, USA).
  • a unit 850-J is connected, through an electrical link to one pixel of the set 126-1 and one pixel of the set 126-2.
  • a method for charging the smart device 190 with the novel charging platform 100 includes a step 1100 of placing the smart device 190 on a platform 126 of the charging station 100, where the platform includes an array of pixels Pij, a step 1102 of measuring with a detection module of the charging station a voltage phase and a current phase of a voltage and a current supplied to a coil 520 of each pixel of the array of pixels Pij, a step 1104 of determining a location 910 of the smart device on the platform, based on a difference between the measured voltage phase and current phase of the pixels, a step 1106 of identifying a set of active pixels 126-1 , 126-2 as those pixels that correspond to the location 910 of the smart device (in one application, corresponding to the plates 192 of the smart device 190), a step 1108 of providing a first polarity to a first set of pixels 126-1 of the set of active pixels, where the first set of pixels 126-1 corresponds to
  • the method may further include a step of compensating an inductance of the set of active pixels 126-1 , 126-2 so that a resonant frequency is achieved between the charging platform 100 and the smart device 190.
  • the of measuring may further include assigning all pixels that have a phase difference between the current and the voltage supplied to the corresponding coil, to the set of active pixels.
  • the method may also include a step of forming corresponding capacitors between each of first and second metal plates of the smart device and a corresponding one of the first set of pixels and the second set of pixels.
  • the disclosed embodiments provide a charging station that uses a CPT mechanism for charging a smart device.
  • the charging station is configured to detect the location of the smart device on its charging platform, and to activate metal plates corresponding only to the location of the smart device to initiate the CPT transfer mechanism.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Power Engineering (AREA)
  • Charge And Discharge Circuits For Batteries Or The Like (AREA)

Abstract

La présente invention concerne une station de charge (100) pour le transfert de puissance capacitif vers un dispositif intelligent (190) qui comprend un module de transfert de puissance capacitif, CPT, (110) conçu pour transférer l'énergie électrique au dispositif intelligent (190) par l'intermédiaire d'une plateforme (126), un module de détection (170) conçu pour détecter un emplacement du dispositif intelligent (190) sur la plateforme (126) et un dispositif de commande (160) conçu pour coordonner le module CPT (110) et le module de détection (170) de sorte qu'une fréquence de résonance soit mise en œuvre entre la station de charge (100) et le dispositif intelligent (190). La plateforme (126) comprend un réseau (900) de pixels Pij et un premier ensemble (126-1) de pixels Pij du réseau (900) de pixels Pij est doté d'une polarité positive (830) et un second ensemble (126-2) de pixels du réseau (900) de pixels Pij est pourvu d'une polarité négative (832), en fonction de l'emplacement du dispositif intelligent (190) sur la plateforme (126).
PCT/IB2022/061239 2021-11-23 2022-11-21 Station de charge à positionnement libre pour dispositifs électroniques et procédé WO2023094974A1 (fr)

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Citations (2)

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