Methods, test apparatus, and computer-readable storage media for testing foreign object detection capabilities of a wireless power transmitter

Abstract

A test device for testing foreign object detection (FOD) capability of a wireless power transmitter. The test device includes a wireless power test receiver and at least one temperature sensor configured to sense a temperature of a foreign object between the wireless power test receiver and the wireless power transmitter during wireless power transmission between the wireless power transmitter and the wireless power test receiver. The test device further includes a memory configured to store the temperature sensed by the at least one temperature sensor and time information on a time at which the temperature is sensed, within a test period in which the wireless power transmission occurs, and a processor configured to calculate a predicted temperature of the foreign object at a future time point after the test period based on the temperature and the time information, and determine a test result based on the predicted temperature.

Description

TECHNICAL FIELD

[0001] The technology described herein relates generally to wireless power delivery, and in particular to testing the ability of a wireless power transmitter to detect foreign objects in a field generated by the wireless power transmitter, referred to as foreign object detection (FOD). BACKGROUND

[0002] Wireless Power Transfer Systems (WPTSs) are becoming increasingly popular as a convenient way to supply power without wires or connectors. WPTSs currently under development in the industry can be divided into two broad categories: magnetic induction (MI) systems and magnetic resonance (MR) systems. Both types of systems include a wireless power transmitter and a wireless power receiver. Such systems can be used to power or charge mobile devices such as smartphones or tablets, as well as in other applications. Such mobile devices include a wireless power receiver that is wirelessly powered by a wireless power transmitter. The wireless power transmitter can be within a pad or stand, such as a pad or stand on which the mobile device can be placed during wireless charging.

[0003] Inductive WPTSs typically operate over a range of allocated frequencies in the hundreds of kilohertz (kHz) using frequency variation as a power flow control mechanism.

[0004] MR WPTSs typically operate at a single resonant frequency, using input voltage regulation to regulate output power. In typical applications, MR WPTSs operate at a frequency of 6.78 MHz.

[0005] Several industry committees have been working to develop international standards for consumer products based on wireless power transfer. SUMMARY

[0006] Some embodiments relate to a test apparatus for testing a foreign object detection (FOD) capability of a wireless power transmitter, the test apparatus comprising: a wireless power test receiver; at least one temperature sensor configured to sense a temperature of a foreign object between the wireless power test receiver and the wireless power transmitter during a wireless power transmission between the wireless power transmitter and the wireless power test receiver; a memory configured to store a plurality of temperatures sensed by the at least one temperature sensor over a test period during which the wireless power transmission occurs, and time information about a plurality of times at which the plurality of temperatures are sensed; and a processor configured to calculate a predicted temperature of the foreign object at a future time point after the test period based on the plurality of temperatures and the time information, and determine a test result based on the predicted temperature.

[0007] Some embodiments relate to a method of testing a foreign object detection (FOD) capability of a wireless power transmitter, the method comprising: sensing, by at least one temperature sensor, a temperature of a foreign object between a wireless power test transmitter and a wireless power test receiver during a wireless power transmission between the wireless power test transmitter and the wireless power test receiver. storing, by a memory, a plurality of temperatures sensed by the at least one temperature sensor over a test period during which the wireless power transmission occurs, and time information about a plurality of times at which the plurality of temperatures are sensed; and calculating, by a processor, a predicted temperature of the foreign object at a future time point after the test period based on the plurality of temperatures and the time information, and determining a test result based on the predicted temperature.

[0008] Some embodiments relate to a non-transitory computer readable storage medium storing instructions that, when executed by a processor, perform a method of testing a foreign object detection (FOD) capability of a wireless power transmitter, the method comprising: obtaining, from a memory, a plurality of temperatures of a foreign object sensed by at least one temperature sensor over a test period during which the foreign object is between a wireless power test receiver and a wireless power transmitter, and time information about a plurality of times at which the plurality of temperatures are sensed; and obtaining, by a processor, a predicted temperature of the foreign object at a future time point after the test period from the plurality of temperatures and the time information.

[0009] The foregoing overview is provided by way of illustration and not of limitation. BRIEF DESCRIPTION OF DRAWINGS

[0010] In the drawings, each identical or nearly identical component that is illustrated in various figures is represented by a like numeral. For purposes of clarity, not every component can be called out in every drawing. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the various aspects of the techniques and devices described herein.

[0011] Figure 1 An example of a test apparatus for testing a FOD capability of a wireless power transmitter is shown in accordance with some embodiments.

[0012] Figure 2a A plot showing the temperature of a reference foreign object (RFO) increasing over time during a FOD test as the RFO is located at different positions.

[0013] Figure 2b A schematic showing an enlarged portion of the RFO at position 2 crossing a threshold in Figure 2a

[0014] FIG. 2c shows an example of a test setup using a thermally conductive material and multiple temperature sensors to perform a temperature difference measurement.

[0015] Figure 3 A test method for testing the foreign object detection capability of a wireless power transmitter is shown in accordance with some embodiments.

[0016] Figure 4a A logarithmic RFO temperature rise prediction based on temperature measurements at the beginning of the test period is shown.

[0017] Figure 4b A logarithmic RFO temperature rise prediction based on temperature measurements later in the test period is shown.

[0018] Figure 5 A linear RFO temperature rise prediction is shown.

[0019] Figure 6 A block diagram of a wireless power system including a wireless power transmitter and a wireless power receiver is shown. DETAILED DESCRIPTION

[0020] ​Wireless power transfer can degrade due to the presence of foreign objects in the field generated by the wireless power transmitter. Conductive objects, such as metal objects, can absorb power due to eddy current induction in the conductive object. The presence of such objects can significantly reduce the efficiency of wireless power transfer. If a metal object is present, the efficiency can be significantly reduced (e.g., from 90% to 40%). In addition, the temperature of the object can significantly increase due to the absorbed power. Techniques have been developed to detect the presence of foreign objects by measuring power loss or by measuring the quality factor (Q-factor). According to these techniques, measuring the Q-factor can be used to determine whether a foreign object is present because the presence of a foreign object reduces the Q-factor of the system, and the presence of high power loss indicates the presence of a foreign object that absorbs power. In the power loss technique, the power transmitted by the wireless power transmitter and received by the wireless power receiver can be measured. The power loss is the difference between the two measurements. If the power loss is outside of an acceptable range (above a threshold), it can be determined that a foreign object is present, and it is determined that a foreign object is not present when the power loss is within the acceptable range. For the Q-factor measurement technique, if the Q-factor is outside of an acceptable range, it can be determined that a foreign object is present, and wireless power transfer can be disabled. On the other hand, if the Q-factor is within the acceptable range, it can be determined that a foreign object is not present, and wireless power transfer can be allowed. When a foreign object is detected, the wireless power transmitter can terminate wireless power transfer or reduce the power level.

[0021] A wireless power transmitter can be tested to verify its ability to detect foreign objects. Such a test can include initiating wireless power transfer between the wireless power transmitter and a wireless power receiver when a reference foreign object (RFO) is between the wireless power transmitter and the wireless power receiver. The temperature of the RFO is measured, and the wireless power transmitter fails the test if the temperature of the RFO exceeds a maximum temperature threshold for a predetermined test period. The wireless power transmitter passes the test if the temperature of the foreign object does not exceed the allowed value for the predetermined test period. However, the inventors have recognized and appreciated that such a test can take a significant amount of time, from tens of minutes to an hour each time. In addition, the test can need to be repeated when the RFO is in different positions. The lengthy test period can consume test resources and / or result in high test costs.

[0022] In some embodiments, the amount of time required to test a wireless power transmitter can be reduced by measuring the temperature of the foreign object at one or more time points during wireless power transmission and using the measured multiple temperatures and multiple measurement times to predict the temperature of the foreign object at a later time point. Any suitable type of prediction can be performed, such as a linear prediction or a logarithmic prediction (e.g., using linear or logarithmic regression). If the predicted temperature at a future time point is below a threshold, the wireless power transmitter passes the test. If the predicted temperature is above the threshold, the wireless power transmitter fails the test.

[0023] Figure 1 An example of a test apparatus 100 for testing a wireless power transmitter 1 for FOD capability is shown in accordance with some embodiments. The test apparatus 100 includes a tester 21, a wireless power test receiver 11 spaced apart from the wireless power transmitter 1 by a gap, and a reference foreign object (“RFO”, also referred to as “FO” or “foreign object”) 20, which can be placed at various test locations between the wireless power transmitter 1 and the wireless power test receiver 11. In Figure 1 In the example shown, the RFO 20 is placed at RFO location 3. However, the RFO 20 can be placed at any suitable location, such as RFO location 1 or RFO location 2. The tester 21 includes a temperature sensor 22 for sensing the temperature of the RFO 20, a memory 23, a processor 24, and an interface 25 for communicating with the wireless power test receiver 11.

[0024] The test apparatus 100 can perform the following operations. The RFO 20 can be placed at a desired location, and the processor 24 of the tester 21 can initiate a test program stored in the memory 23. The test program can cause the tester 21 to control the wireless power test receiver 11 to have suitable characteristics (e.g., power loading) and / or to communicate with the wireless power transmitter to bring the wireless power transmitter 1 to a desired power level of wireless power transmission. To do so, the wireless power test receiver 11 can communicate with the wireless power transmitter 1 according to a communication protocol supported by the wireless power transmitter 1. The temperature sensor 22 measures the temperature of the RFO 20 at different times over a test period, and can store the measured temperature values and their measurement times in the memory 23. At a suitable time, the processor 24 can use the measured temperature values and their measurement times to predict the temperature of the RFO 20 at a future time after the end of the test period in which wireless power transmission occurs. The test can then pass or fail based on whether the predicted future temperature exceeds a threshold value. In other embodiments, the tester 21 can send the temperature measurements to another computing device (e.g., a server) to perform the prediction, and can send the result of the prediction (e.g., predicted temperature value, pass / fail) back to the tester 21, as the techniques described herein are not limited to the tester 21 performing the prediction.

[0025] The temperature rise in the RFO 20 can vary significantly when the RFO 20 is placed at different locations due to spatial variations in the magnetic field. Therefore, in some embodiments, multiple tests can be performed with the RFO 20 placed at different locations. Figure 2a Temperature rise curves captured over time are shown for the RFO 20 placed at three example locations. The correspondence between the spatial location of the RFO 20 and the slew rate of the temperature rise curve can not be accurate, and is given here as an example among various possible cases.

[0026] Figure 2a An example test period of 600 seconds (10 minutes) is shown for the RFO 20 temperature rising fastest at location 1 and reaching the example threshold of 60°C before the end of the test period. This is an example of the wireless power transmitter 1 failing the test because the RFO 20 temperature exceeds the threshold within the established test period.

[0027] Figure 2a The RFO 20 temperature is shown rising slower at location 2, not reaching the threshold within the test period, but exceeding the threshold soon after the end of the test period. Figure 2b The RFO 20 temperature is shown crossing the 60°C threshold at location 2. Figure 2athe test period (in this case, 600 seconds), the RFO 20 temperature is slightly below the threshold, i.e., point 51, but quickly exceeds the threshold after the test stop time (point 52). Formally, this constitutes a "pass" of the test, although this is a marginal case that can not be accepted.

[0028] Figure 2a shown at position 3, the RFO 20 temperature remains substantially below the threshold during the test period, but would significantly exceed the threshold in the final follow-up. The result of this test can be considered satisfactory. Formally, this is a "pass" result according to the rules currently established under the Qi and IEC standards, although a cautious product manufacturer can consider this test result not satisfactory.

[0029] The scenarios associated with positions 2 and 3 can be observed by testing for a sufficiently long test period. However, as mentioned above, it is desirable to keep the test period as short as possible. Therefore, in some embodiments, predicting future temperature values of the RFO can allow keeping the test period short while providing a level of confidence that the temperature of the foreign object will not exceed the threshold during a limited, extended time interval.

[0030] The RFO 20 can be made of various materials and can have various shapes to simulate various real-world situations. Moreover, the RFO 20 can be constructed in a way that mitigates the thermal effects of the wireless power test receiver 11 and the wireless power transmitter 1 on this RFO 20. For example, such RFO 20 can be sandwiched between or embedded in materials with predefined thermal conductivities, which can provide repeatable RFO temperature readings as the RFO dissipates power due to its interaction with the magnetic field generated by the wireless power transmitter 1 and not due to heat from the wireless power transmitter 1 or the wireless power test receiver 11. Figure 2c shows a schematic of a test setup in which the RFO 20 is between a top thermally conductive layer 41 and a bottom thermally conductive layer 42, which define the thermal transfer between the RFO 20 to the wireless power test receiver 11 and the wireless power transmitter 1, respectively. In some embodiments, the thermally conductive materials 41 and 42 can have a thermal insulation value of 5 < Rth < 150 °C / W.

[0031] In some embodiments, a temperature difference measurement of the RFO 20 can be performed. For example, in Figure 2c, using three temperature sensors 22a, 22b and 22c that measure the temperature within the thermally conductive layer 41, the RFO 20 and the thermally conductive layer 42 respectively, a mathematical operation is performed on the measurements of the three temperature sensors to obtain a temperature difference measurement of the RFO 20, which is indicative mainly of the temperature due to the interaction of the RFO with the magnetic field. The predicted temperature of the foreign object at a future point in time after the test period can be based on the temperature difference measurement. The temperature sensors 22 (including 22a, 22b and 22c) can be any suitable type of temperature sensor, for example a thermocouple.

[0032] Figure 3 A test method 200 for testing the foreign object detection capability of a wireless power transmitter is shown, in accordance with some embodiments. In step S30, the wireless power transmitter 1 (WPTX-DUT), the wireless power test receiver 11 (Test PRX) and the RFO 20 are positioned and configured for testing. In step S31, wireless power transmission can be initiated between the wireless power transmitter 1 and the wireless power test receiver 11, and RFO temperature measurement is started. In step S32, it is checked whether the RFO temperature exceeds the allowed maximum temperature (threshold). If so, the wireless power transmitter 1 fails the test, and the test ends. If not, the temperature of the RFO and the time at which the measurement was taken is stored in step S33. It is then checked in step S34 whether the test period has expired. If not, after a suitable delay between measurements (S35), the method returns to step S32, and the measurements can be repeated until the maximum RFO temperature is exceeded or the test period expires. When it is determined in step S34 that the test period has expired, the future temperature of the RFO at a future time (T2) after the test period is predicted in step S36. As described above, the prediction can be performed using the temperature measurements and timing information. For example, in some embodiments, the temperature measurements and their timings can be treated as points, and a linear or logarithmic regression can be performed to obtain a line or logarithmic curve that fits the points. The predicted temperature at time T2 can be evaluated in step S37. For example, the line or logarithmic curve can be evaluated for the future time T2. If the predicted temperature at time T2 exceeds the threshold, the test fails. If not, the test passes. The result of the test can be communicated to a human in any suitable way, for example by being displayed on a display device that is part of the tester 21 or on a display device connected to the tester 21.

[0033] Figure 4aRFO 20 temperature rise prediction using RFO readings taken at different time intervals within a test period is depicted. Time TO is the start of data collection, T1 is the end of data collection. The test period is the time period during which wireless power transfer is performed for testing purposes. Time T2 is a future time at which the temperature prediction is computed. In this example, the prediction is performed by fitting a natural log curve to the data (e.g., using a log regression).

[0034] The following relationships hold for times TO, T1, T2.

[0035] • TO > 0 - Data collection for the RFO temperature rise prediction starts at or after the start of wireless power transfer.

[0036] • TO < T1 < test end time

[0037] • T2 > test end time.

[0038] In Figure 4a , the temperature data points are taken at the start of the test (e.g., TO is about 20 seconds). Since the temperature changes quickly at the start of the test and slowly later in the test, using data from the start of the test can result in a less accurate prediction than using data from later in the test. In particular, using data from early in the test can overestimate the future temperature of the RFO 20.

[0039] Figure 4b An embodiment is shown in which the prediction is performed using multiple temperatures measured later in the test period. In this example, TO and T1 are compared to the embodiment of Figure 4a . Since the temperature changes slowly later in the test, the prediction of the temperature of the RFO 20 can be more accurate. Note that compared to the example of Figure 4a , the regression coefficient R 2 is higher in the example of Figure 4b . In some embodiments, the measurements can be postponed by a delay, or the measurements can not be postponed, and the measurements used for the prediction can be those obtained after the appropriate delay. In some embodiments, the delay can be at least 30 or 60 seconds, and less than half of the test period. However, this is one example, and any suitable delay can be used. In the formula of the graph, x represents time, y represents temperature, and Log.(RFO at position 2) represents the log curve for the RFO at position 2.

[0040] Figure 5 An embodiment is shown in which a linear prediction is used. Linear prediction requires less computational resources than log prediction. When the RFO temperature is close to the maximum allowed temperature threshold ( Figure 5Linear prediction (e.g., regression) is most accurate as the test period approaches its end (e.g., when the RFO temperature is within 10% of the threshold). For example, a linear regression can be used when the RFO temperature is within 10% of the threshold. In this case, the error associated with the prediction can be very small, and computational resources can be saved to perform other tasks. Linear regression is one way to perform linear prediction. Other ways to perform linear prediction can involve using the slew rate of the temperature rise or the angle at which the RFO temperature rises as it approaches the threshold, for example. In some embodiments, when the regression is highly linear (e.g., R 2 >0.9) and the temperature prediction for T2 exceeds the threshold, it can be determined that the wireless power transmitter failed the test.

[0041] Test tool designers can use different prediction techniques and their numerical expressions optimized for various microprocessor implementations. In some embodiments, a combination of different prediction techniques can be used. For example, a logarithmic prediction can be used when the RFO 20 temperature is far below the threshold, and a linear prediction can be used when the RFO 20 temperature is closer to the threshold. According to yet another embodiment, the internal temperature of the wireless power test receiver 11 during the test can also be a factor that influences the use of an approximation method.

[0042] The approximation method and mathematical expression can also be selected based on the RFO structure. For example, in some embodiments that use multiple thermal sensors (e.g., thermocouples) within the RFO 20, the average temperature between the multiple thermocouples or other mathematical operations can be calculated to help test robustness.

[0043] In an alternative embodiment, if the sensed temperature changes slowly, the rate of rise of the temperature is low, then the time period of TO to T1 can be set to be short, and if the sensed temperature changes quickly, the rate of rise of the temperature is high, then the time period of TO to T1 can be set to be long, so the time period of TO to T1 is variable and based on the rate of change of the sensed temperature.

[0044] Wireless power transmission and related devices are discussed below.

[0045] Figure 6A block diagram of a wireless power system 300 is shown that includes a wireless power transmitter 1 and a wireless power test receiver 11. The wireless power transmitter 1 has a drive circuit 7 that includes an inverter 3 that drives a transmit coil 10 through a matching network 6. The wireless power transmitter 1 can include a regulated voltage source 2 (e.g., a voltage regulator) that provides a regulated DC voltage to the inverter 3. The regulated voltage source 2 generates a regulated DC output voltage in response to a control stimulus from a controller 5. In some embodiments, the drive circuit 7 can be a class-D or class-E amplifier that converts a direct current (DC) voltage at the input of the inverter 3 to an alternating current (AC) output voltage to drive the transmit coil 10. Generating an alternating current output voltage enables wireless power transfer through electromagnetic induction. The controller 5 can control a signal generator 9 to drive the inverter 3 with a signal at a selected wireless power transfer frequency. As an example, the inverter 3 can switch at frequencies between 100 and 205 kHz to transfer power to a wireless power receiver designed to receive wireless power according to the Qi specification for low-power Qi receivers and medium-power Qi receivers (80-300 kHz). The inverter 3 can switch at higher frequencies (e.g., frequencies greater than 1 MHz) within the ISM band (e.g., 6.765 MHz to 6.795 MHz) to transfer power to a receiver designed to receive wireless power using MR technology. However, these frequencies are described by way of example only, as wireless power can be transferred according to any suitable specification at various suitable frequencies. The controller 5 can be an analog circuit or a digital circuit. The controller 5 can be programmable and can instruct the signal generator 9 to generate a signal at a desired transfer frequency based on stored program instructions, causing the inverter 3 to switch at the desired transfer frequency. The matching network 6 can facilitate wireless power transfer by presenting a suitable impedance to the inverter 3. The matching network can have one or more capacitive or inductive elements or any suitable combination of capacitive and inductive elements. As the transmit coil 10 can have an inductive impedance, in some embodiments, the matching network 6 can include one or more capacitive elements that, when combined with the impedance(s) of the transmit coil 10, present an impedance to the output of the inverter 3 suitable for driving the transmit coil 10. In some embodiments, the resonant frequency of the matching network 6 can be set to equal or approximately equal to the switching frequency of the inverter 3 during wireless power transfer. The transmit coil 10 can be implemented by any suitable type of conductor. The conductor can be a wire, including a solid wire or Litz wire, or a patterned conductor, such as a patterned conductor of a PC board or an integrated circuit.

[0046] An alternating current (AC) current in the transmit coil 10 produces an oscillating magnetic field according to Ampere's law. The oscillating magnetic field induces an alternating voltage into the receiver coil 12 of the wireless power receiver 11 according to Faraday's law. The AC voltage induced in the receiver coil 12 is provided through the matching network 13 to a rectifier 14, which produces an unregulated DC voltage. The rectifier 14 can be a synchronous rectifier or can be implemented using diodes. The unregulated DC voltage is regulated using a DC / DC converter 15, the output of which can be filtered and provided as an output voltage Vout to a load. In some alternative embodiments, the DC / DC converter 15 can be replaced by a linear regulator or a battery charger, or eliminated altogether. In some embodiments, the wireless power transmitter 1 and / or the wireless power test receiver 11 can have communication circuitry (e.g., internal or external to the controllers 5 and 21) for communicating with the wireless power receiver 11 through in-band or out-of-band communication. Similarly, the wireless power receiver 11 can have communication circuitry for communicating with the wireless power transmitter 1. The wireless power receiver 11 can send feedback information to the wireless power transmitter 1 indicating the power required at the wireless power receiver 11 or a change in the power level to be provided. In response, the wireless power transmitter 1 can increase or decrease its power output accordingly. The wireless power transmitter 1 can control the amount of power transmitted by changing the voltage drive level, the frequency of the transmitted signal, or both. Any suitable power control technique can be used.

[0047] Reference is made to Figure 6 If a conductive foreign object 20 enters the field produced by the transmit coil 10 of the wireless power transmitter 1, the wireless power transmission efficiency can decrease and / or the conductive foreign object 20 can be subjected to significant heating. Examples of conductive foreign objects 20 include, by way of example, a coin, a paperclip, and a key.

[0048] In some embodiments, foreign object detection can be performed by energizing and controlling the drive circuit of the wireless power transmitter and measuring the transient characteristics in the wireless power transmitter to measure the Q-factor and the resonant frequency. Based on the transient characteristics, the wireless power transmitter can determine whether a foreign object is present in the field produced by the wireless power transmitter. However, the Q-factor and the resonant frequency can be measured in any suitable manner and are not limited to measuring the transient characteristics. In some embodiments, the Q-factor and / or the frequency can be detected by frequency domain measurements or a combination of time and frequency domain measurements.

[0049] Additional aspects

[0050] As described above, the wireless power transmitter and receiver can be controlled using a controller (e.g., controller 5, processor 24), which can be implemented by any suitable type of circuitry. For example, the controller can be implemented using hardware or a combination of hardware and software. When implemented using software, suitable software codes can be executed on any suitable processor (e.g., a microprocessor) or set of processors. The controller or controllers can be implemented in a number of ways, such as with dedicated hardware, or with general purpose hardware (e.g., one or more processors) that is programmed using microcode or software to perform the functions described above.

[0051] In this respect, it should be appreciated that one implementation of the embodiments described herein includes at least one computer-readable storage medium (e.g., RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile discs (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to encode desired computer program code in the form of computer-executable instructions, or a combination thereof) encoded with computer program code (i.e., computer-executable instructions) that, when executed on one or more processors, performs the functions described above of one or more embodiments. Moreover, it should be appreciated that the reference to a computer program code in the preceding description is not restricted to application software running on a host computer. Rather, the term computer program code and software in this context refers to any type of computer code, e.g., application software, firmware, microcode, or any other form of computer instruction that can be executed on a processor to implement various aspects of the technology discussed herein.

[0052] The various aspects of the apparatus and techniques described herein can be used alone, in combination, or in various arrangements not specifically discussed in the embodiments described in the foregoing description and portions thereof, and are not limited in their application to the details and arrangement of components set forth in the foregoing description or illustrated in the accompanying drawings. For example, aspects described in one embodiment can be combined with aspects described in other embodiments in any manner.

[0053] The use of the ordinal terms such as "first," "second," "third," etc. to modify a claim element does not imply any priority, precedence or order of one claim element over another claim element, but is used merely as labels for the purpose of distinguishing between the claim elements so modified. The use of the terms "a" and "an" and "the" to modify the claim element does not exclude the presence of zero, one, or more than one element, but merely indicates that one or more elements are present.

[0054] Also, the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of "including," "comprising," or "having," "containing," "involving," and variations thereof herein, is meant to encompass the items listed thereafter and equivalents thereof as well as additional items.

Claims

1. A testing apparatus for testing the foreign object detection (FOD) capability of a wireless power transmitter, characterized in that, The testing apparatus includes: At least one temperature sensor is configured to sense the temperature of a foreign object between the wireless power transmitter and the wireless power test receiver during wireless power transmission between the wireless power transmitter and the wireless power test receiver; A memory is configured to store multiple temperatures sensed by at least one temperature sensor during a test period in which the wireless power transmission occurs, and time information regarding multiple times at which the multiple temperatures are sensed; and The processor is configured to calculate the predicted temperature of the foreign object at a future time point after the test period based on the plurality of temperature and time information, and to determine the test result based on the predicted temperature, wherein the test result indicates whether the FOD capability test of the wireless power transmitter has passed.

2. The testing apparatus as described in claim 1, characterized in that, The testing apparatus also includes: a wireless power test receiver; the processor is configured to run a test program stored in the memory of the testing apparatus.

3. The testing apparatus as described in claim 2, characterized in that, The processor is configured to control the wireless power test receiver according to the test program by communicating with the wireless power test receiver via an interface.

4. The testing apparatus according to claim 3, characterized in that, The processor is configured to control the load of the wireless power test receiver to obtain the power transmission level from the wireless power transmitter.

5. The testing apparatus according to claim 3, characterized in that, The testing device is configured to perform the test when the foreign object is in a first position, and is configured to perform an additional test when the foreign object is in a second position different from the first position.

6. The testing apparatus according to claim 1, characterized in that, The processor is configured to perform a linear prediction based on the plurality of temperatures and the plurality of times to obtain the predicted temperature.

7. The testing apparatus as described in claim 1, characterized in that, The processor is configured to perform logarithmic prediction based on the plurality of temperatures and the plurality of times to obtain the predicted temperature.

8. The testing apparatus as described in claim 1, characterized in that, The processor is configured to perform the calculations using multiple temperatures sensed after a delay following the start of the test period.

9. The testing apparatus as described in claim 8, characterized in that, The delay is determined based on the rate of change of the sensed temperature.

10. The testing apparatus as described in claim 8, characterized in that, The delay is at least 30 seconds and less than half of the test period.

11. The testing apparatus as described in claim 1, characterized in that, The at least one temperature sensor includes a plurality of temperature sensors.

12. The testing apparatus as described in claim 11, characterized in that, The plurality of temperature sensors are configured to measure temperature at multiple locations inside and / or outside the foreign object, and to obtain a temperature difference measurement result based on the temperature measured at the multiple locations. The calculation of the predicted temperature of the foreign object at a future time point after the test period is based on the temperature difference measurement result.

13. The testing apparatus as described in claim 1, characterized in that, Further includes: The thermally conductive material between the foreign object and the wireless power transmitter, the thermally conductive material between the foreign object and the wireless power test receiver, or both.

14. A method for testing the foreign object detection (FOD) capability of a wireless power transmitter, characterized in that, The method includes: During wireless power transmission between the wireless power transmitter and the wireless power test receiver, at least one temperature sensor senses the temperature of the foreign object between the wireless power test receiver and the wireless power transmitter; The memory stores multiple temperatures sensed by the at least one temperature sensor during the test period in which the wireless power transmission occurs, as well as time information about multiple times when the multiple temperatures were sensed; The processor calculates the predicted temperature of the foreign object at a future time point after the test period based on the multiple temperature and time information, and determines the test result based on the predicted temperature, wherein the test result indicates whether the FOD capability test of the wireless power transmitter has passed.

15. The method as described in claim 14, characterized in that, The test program for the sensing and storage components is executed by the processor.

16. The method as described in claim 15, characterized in that, Also includes: The wireless power test receiver is controlled according to the test procedure by communicating with the wireless power test receiver via an interface.

17. The method according to claim 16, characterized in that, Further includes: The load of the wireless power test receiver is controlled to obtain the power transmission level from the wireless power transmitter.

18. The method according to claim 14, characterized in that, The test is performed when the foreign object is in a first position, and an additional test is performed when the foreign object is in a second position different from the first position.

19. The method according to claim 14, characterized in that, The predicted temperature is obtained by performing a linear prediction based on the plurality of temperatures and the plurality of times.

20. The method as described in claim 14, characterized in that, Logarithmic prediction is performed based on the plurality of temperatures and the plurality of times to obtain the predicted temperature.

21. The method as described in claim 14, characterized in that, The calculation is performed using multiple temperatures sensed after a delay following the start of the test period.

22. The method as described in claim 21, characterized in that, The delay is at least 30 seconds and less than half of the test period.

23. A non-transitory computer-readable storage medium storing instructions that, when executed by a processor, perform a method for testing the foreign object detection (FOD) capability of a wireless power transmitter, characterized in that... The method includes: Retrieve from memory multiple temperatures of a foreign object sensed by at least one temperature sensor during a test period between the wireless power test receiver and the wireless power transmitter, and time information regarding multiple times at which the multiple temperatures were sensed; and The processor obtains the predicted temperature of the foreign object at a future time point after the test period based on the multiple temperature and time information, and determines the test result based on the predicted temperature, wherein the test result indicates whether the FOD capability test of the wireless power transmitter has passed.

24. The non-transitory computer-readable storage medium according to claim 23, characterized in that, The processor is configured to perform a prediction to obtain the predicted temperature.

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