Wireless charging interoperability testing method and system based on frequency impedance characteristics

Abstract

A wireless charging interoperability testing method and system based on frequency impedance characteristics, relating to the technical field of wireless power transfer. The method comprises: changing

Description

The present invention relates to the technical field of wireless power transmission, and specifically to a wireless charging interoperability testing method and system based on frequency-impedance characteristics. Background Art To ensure interconnection and compatibility between various ground-side and onboard devices in electric vehicle (EV) wireless charging systems, interoperability testing has gradually become an important technical process. The interoperability- requirement of a wireless charging system stipulates that, when the tested onboard device is paired with a ground-side device, the system must be able to deliver power at the efficiency specified by standards. As wireless charging technology for electric vehicles continues to develop, interoperability evaluation has become a critical step for large-scale commercialization. Interoperability in a wireless charging system refers to the ability of different ground-side and onboard devices to match and deliver the rated power at the specified efficiency. Currently, interoperability testing in wireless charging systems mainly involves pairing a reference device with the device under test, then measuring power efficiency or port impedance at a single frequency for evaluation. However, existing methods for evaluating the interoperability of EV wireless charging systems still suffer from the following limitations: First, current testing methods fail to consider the influence of operating frequency on interoperability. According to the requirements of the Ministry of Industry and Information Technology (MIIT) of China, onboard wireless charging systems rated under 22 kW are permitted to operate within the 79^ kHz range. However, the national standard reference devices all have a nominal operating frequency of 85.5 kHz. Relying solely on this single frequency for interoperability’ testing may cause devices that are otherwise interoperable within the permitted frequency band to fail the test. This unintentionally raises the bar for interoperability compliance and hampers industrialization. Second, existing evaluation methods fail to consider the soft-switching (ZV S) requirement of groundside inverters. To ensure zero-voltage switching, systems are generally required to present a weakly inductive equivalent input impedance under interoperable conditions, reducing switching losses and voltage stress. However, current test methods ignore this issue. As a result, some products that pass the test may fail in real interoperability scenarios due to excessive inverter losses or over-voltage stress, causing the ground-side device to trigger over-temperature or over-voltage protection and ultimately fail to interoperate. To address the above shortcomings in the prior art, the present invention proposes a wireless charging interoperability testing method and system based on frequency-impedance characteristics. The objective is to take both operating frequency and inverter soft-switching behavior into account in interoperability testing, thereby providing a more comprehensive testing system and method that includes both interoperability determination and interoperability level classification, improving the completeness and accuracy of such tests. Summary of the Invention In view of the problems, the present invention is proposed. Accordingly, the technical problem solved by the present invention is: how to improve the comprehensiveness and accuracy of interoperability testing. To solve the above technical problem, the present invention provides the following technical solution: a wireless charging interoperability testing method based on frequency-impedance characteristics, which comprises the following steps: • Altering the operating frequency of the ground reference device inverter via a frequency sequence; • Measuring and recording the impedance at the port of the ground reference coil and plotting an impedance test graph; • Determining whether the tested onboard device is interoperable and identifying its interoperability level based on the correlation between the impedance scatter points and a reference region formed by four boundary curves. In a preferred embodiment of the wireless charging interoperability testing method based on frequency-impedance characteristics described above: • Altering the operating frequency of the ground reference device inverter includes defining a minimum and maximum test frequency, fmin and fmax, respectively. • A frequency scan is performed over the interval {fmm> fmax} using a step size f0. yielding a frequency sequence { / 1, / 2- ■■■’fn}, • The corresponding angular frequency sequence is { m2,..., }, and the inverter is set to operate sequentially according to this frequency sequence. In another preferred embodiment: • Measuring and recording the impedance at the port of the ground reference coil includes pairing the tested device with the reference device for charging and obtaining the frequency-impedance characteristics of the onboard device as {Z1, Z2,..., Zn}. • A reference frequency fr E {fy, f2,..., fn} is defined, and its corresponding reference impedance isZr E }Z1,Z2,..., Zn}. In a further preferred embodiment: • The reference region is enclosed by four boundary curves: a lower boundary, upper boundary, left boundary, and right boundary. The lower boundary is defined as: / m(Z) - a>LGA —“—_ x--------— LCL7lunin Y Re(Z} - rGA where LGA is the self-inductance of the reference ground coil, rGA is the internal resistance of the reference ground coil, or is the angular frequency of the test system, 9max is the maximum allowable impedance angle for zero-voltage switching (ZVS) during inverter operation, / m(Z)is the imaginary part of the measured impedance, and Re(Z) is the real part of the measured impedance. The upper boundary is defined as: Im(Z) = a)LGA The left boundary is defined as: n2 co2 oumax where is the inductance of the series compensation inductor on the ground side of the reference device, Umax is the upper limit of the inverter input voltage of the ground reference device, and P is the specified output power of the inverter. The right boundary is defined as: h2oj2LLP = „„2 + ^^min where Umin is the lower limit of the inverter input voltage of the ground reference device. In a further preferred embodiment of the wireless charging interoperability testing method based on frequency-impedance characteristics: The determination of whether the tested onboard device is interoperable includes verifying whether any impedance point Zm in the frequency-impedance characteristic sequence lies within the reference region, or whether a curve fitted to the impedance sequence intersects the reference region. In such cases, the device is deemed to pass the interoperability test. Specifically, the frequency-impedance characteristic sequence contains a point Zm that satisfies the following conditions: ( n2a)2LfiP Re(Zm) <—3 *— + rGA mln n2a)2I?flP ' Re^Z^ >2 — + rGA max < G)mLGA \Ji7i(Zjn) >tan0max(Re(Zjn) ^ga) T G)mLGA Alternatively, the frequency-impedance characteristic sequence contains two consecutive points Zm and Zm+1 that satisfy: G)mLGA)(Jl7l(Zm+y') ^m+lLGA) <® 7l2G)2L2f}P ---+ rGA <Re(Zm) <max Tl2<jy2L2rP QTj2 oumin + rGA jm2 + rGA Re(Zm+J <2 + rGA oumax oumin where Zm denotes any impedance value in the frequency-impedance characteristic sequence, a)m is the angular frequency corresponding to Zm, and Zm+1 is the next impedance value following Zm in the sequence. In another preferred embodiment of the wireless charging interoperability testing method based on frequency-impedance characteristics as described in the present invention: The classification of interoperability levels includes the following: • If the tested device passes the interoperability test and the reference impedance Zr satisfies the following conditions, the device is evaluated as Class I interoperable, indicating that the onboard device can operate effectively with any ground-side device compliant with national standards. • If the tested device passes the interoperability test but the reference impedance Zr does not satisfy the following conditions, the device is evaluated as Class II interoperable, indicating that the onboard device can only operate effectively with ground-side equipment that has frequency-adjustment capability. The conditions described above are expressed as: n2(i.)rL2nP Re(Zr) ”77772----+ rGA VUmin n2a)rL%iP ' Re(Zr) > -----H rGA oij2 0 / 1 oumax < Im(Zr) >—tandmax(Re(Zr) - rGA) + a)rLGA where is the angular frequency corresponding to the reference impedance Zr. Another objective of the present invention is to provide a wireless charging interoperability testing system based on frequency-impedance characteristics, which alters the operating frequency of the inverter in the ground reference device, measures and records the impedance at the reference ground coil port, and determines interoperability of the onboard device based on the correlation between the measured impedance and the predefined reference region. This solution addresses the problems in existing testing methods that fail to consider die effects of frequency on interoperability and the soft-switching requirement of the ground-side inverter. To address the above technical challenges, the present invention proposes the following technical solution: A wireless charging interoperability testing system based on frequency-impedance characteristics, comprising: - a power factor correction unit, - a DC-DC buck converter, - a frequency-adjustable inverter, - a reference ground coil and compensation network, - an impedance testing unit, and - an information processing unit. In a preferred embodiment of the system, the power factor correction unit and DC-DC buck converter are used to supply a regulated DC input voltage. The frequency-adjustable inverter provides high-frequency excitation within a defined frequency range. The reference ground coil and compensation network are used to transfer energy via electromagnetic coupling to the onboard device under test. The impedance testing unit is used to measure the impedance at the reference ground coil port under different excitation frequencies. The information processing unit is configured to analyse the series of measured impedances and generate the interoperability test results. A computer-readable storage medium storing a computer program, wherein the computer program is executed by a processor to implement the steps of the wireless charging interoperability testing method based on frequency-impedance characteristics as described above. Advantages of the Invention: The present invention proposes a wireless charging interoperability testing method based on frequency-impedance characteristics, which significantly enhances tine comprehensiveness and accuracy of interoperability testing by considering the impact of operating frequency and the soft-switching behaviour of ground-side inverters. Tins method not only fully covers the wireless charging frequency requirements set by the Ministry of Industry and Information Technology (MIIT) of China but also enables the evaluation of the stability and reliability of devices under real application conditions. As a result, it promotes the industrialization and widespread adoption of wireless charging technology for electric vehicles and provides strong technical support for the development of the entire industry. Description of the Drawings To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings referenced in the description of the embodiments are briefly introduced below. These drawings represent only some embodiments of the present invention. A person skilled in the art may derive additional drawings based on these without exercising inventive effort. • Figure 1 is a flowchart illustrating the overall process of the wireless charging interoperability testing method based on frequency-impedance characteristics according to the first embodiment of the present invention. • Figure 2 is a diagram of the impedance reference region for the wireless charging interoperability testing method based on frequency-impedance characteristics according to the first embodiment of the present invention. • Figure 3 is a block diagram of the wireless charging interoperability testing system based on frequency-impedance characteristics according to the second embodiment of the present invention. Embodiments To make the objectives, features, and advantages of the present invention more apparent and understandable, the following section provides a detailed description of specific embodiments of the invention with reference to the accompanying drawings. It is evident that the described embodiments represent only a portion of the invention, not all of it. All other embodiments derived by those skilled in the art without involving inventive steps shall also fall within the scope of protection of the present invention. Embodiment 1 With reference to Figures 1 and 2, a first embodiment of the present invention provides a wireless charging interoperability testing method based on frequency-impedance characteristics, characterized in that: • SI: Altering the operating frequency of the ground reference device inverter using a frequency sequence. Altering the operating frequency of the ground reference device inverter includes defining a minimum test frequency fmin and a maximum test frequency fmax. A scan is performed over the interval {fmin> fmax) using a frequency step size f0, generating a frequency sequence { / 1, / 2,■ ■ • , fn}- The corresponding angular frequency sequence is {u^, m2,, and the inverter's operating frequency is sequentially set according to the values in this frequency sequence. • S2: Measuring and recording the impedance at the port of the ground reference coil and plotting the impedance test graph. Measuring and recording the impedance at the ground reference coil port includes performing matched charging between the device under test and the reference device, thereby obtaining the frequency-impedance characteristics of the tested onboard device as {Z1;Z2, ■■•> ^n}- A reference frequency fr G { / 1, / 2, ■■■’fn} is defined, and the corresponding reference impedance is Zr G {Z1; Z2,..., Z„}. Additionally, the impedance test graph corresponds to the reference region shown in Figure 2. The measured impedance points are projected onto this graph, and one can visually determine whether interoperability requirements are met—i.e., whether the measured points fall within the reference region (in which case the requirements are satisfied) or outside it (in which case they are not). • S3: Determining whether the tested onboard device is interoperable and identifying its interoperability level based on the correlation between the impedance scatter points and the reference region enclosed by four boundary curves. As shown in Figure 2, the reference region is bounded by four curves: a lower boundary, upper boundary, left boundary, and right boundary. The lower boundary is defined as: / m(Z) - o)Lga _ -- bCLYLUwi fjy Re(Z} - rGA where LGA is the self-inductance of the reference ground coil, rGA is the internal resistance of the reference ground coil, w is the angular frequency of the test system, 0max is the maximum allowable impedance angle for zero-voltage switching (ZVS) during inverter operation, / m(Z)is the imaginary part of the measured impedance, and Re(Z) is the real part of the measured impedance. The upper boundary is defined as: Tire left boundary is defined as: lm(Z) = a)LGA n2a>2LfAP Re(Z) =---+ max where is the inductance of the series compensation inductor on the ground side of the reference device, Umax is the upper limit of the inverter input voltage of the ground reference device, and P is the specified output power of the inverter. The right boundary is defined as: Re(Z) ji2oj2L^P ^112 oumin + rGA where Umin is the lower limit of the inverter input voltage of the ground reference device. To determine whether the tested onboard device is interoperable, if any point Zm in the frequency-impedance characteristic sequence lies within the reference region, or if the curve fitted to the impedance sequence intersects the reference region, the device is considered to have passed the interoperability test. Specifically, this condition is met if the following holds: f n2a)2LlAP Re(Zm)< ...........................................+ rGA QUmin n2a)2 LftP ' Re(Zm) >Z— + rGA max I^l(^m^ — ^m^GA > t(lTl6max(Re^Z-yn) ^ga) + ^m^GA Alternatively, if the impedance sequence contains two consecutive points Zm and Zm+1 that satisfy: (jt)mL‘GA)U^'(.Zm+±) ^m+l^GAt) <® 7I2G)2L2flP qtj2 oumax Tl2G)2L2flP —+r“ oumin ojt2 + rGA p„2 + VGA max min where Zm is any impedance value in the sequence, a)m is its corresponding angular frequency, and Zm+1 is the next impedance value in the sequence. The classification of interoperability levels is as follows: If the tested device passes the interoperability test and the reference impedance Zr satisfies the following conditions, the device is evaluated as Class I interoperable, meaning it can interoperate well with any device conforming to national standards. If the tested device passes the interoperability test but the reference impedance Zr does not satisfy these conditions, the device is evaluated as Class II interoperable, indicating it can only interoperate well with ground-side equipment that supports frequency adjustment. The conditions are expressed as: n2a)2 Lj-,P RetfA r„2 --+ rGA ^^min ' Re(Zr) > ii2^2^? QJf2 oumax + rGA lm(Zr) <wrLGA k Im^ZA >-tan0max( / ?e(X) - rGA) + mt^ca where is the angular frequency corresponding to the reference impedance Zr. Embodiment 2 With reference to Figure 3, a second embodiment of the present invention provides a wireless charging interoperability testing system based on frequency-impedance characteristics. The wireless charging interoperability testing system based on frequency-impedance characteristics comprises the following components: • a power factor correction unit, • a DC-DC buck converter, • a frequency-adjustable inverter, • a reference ground coil and compensation network, • an impedance testing unit, and • an information processing unit. The power factor correction unit and DC-DC buck converter are configured to supply a regulated DC input voltage. The frequency-adjustable inverter is configured to provide high-frequency excitation within a defined frequency range. Hie reference ground coil and compensation network are configured to transfer energy to the onboard device under test via electromagnetic coupling. The impedance testing unit is configured to measure the impedance at the port of the reference ground coil under different excitation frequencies. The information processing unit is configured to analyse the sequence of measured impedances and generate the interoperability test result. If the above-de scribed functions are implemented in the form of software function modules and sold or used as standalone products, they may be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or at least the part contributing to the existing art, may be implemented as a software product. The software product is stored on a storage medium and includes a set of instructions that enable a computer device (such as a personal computer, server, or network device) to execute all or part of the steps of the method described in the various embodiments of the present invention. Hie storage medium may include USB drives, portable hard disks, read-only memory (ROM), random access memory (RAM), magnetic disks, optical disks, or any other medium capable of storing program code. The logic and / or steps shown in the flowcharts or described in this document can be considered as a sequence of executable instructions, which may be implemented in any computer-readable medium for use by or in connection with an instruction execution system, apparatus, or device—such as a computer-based system, processor-containing system, or any other system capable of fetching and executing instructions. For the purposes of this specification, a "computer-readable medium" may be any device that can contain, store, communicate, propagate, or transmit the program for use by such systems, apparatuses, or devices. More specific examples of computer-readable media (a non-exhaustive list) include electronic devices with one or more electrically conductive connections (wiring), portable computer disk enclosures (magnetic storage devices), random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM) or flash memory, optical fiber devices, and portable compact disc read-only memory (CD-ROM). Additionally, a computer-readable medium may even include paper or other suitable media on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium, then editing, interpreting, or otherwise processing it as needed, and finally storing it in computer memory. Various parts of the present invention may be implemented using hardware, software, firmware, or any combination thereof. In the above embodiment, multiple steps or methods may be implemented by software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, it may be accomplished using one or a combination of the following techniques well known in the art: discrete logic circuits with logic gates for implementing logic functions on data signals, application-specific integrated circuits (ASICs) with appropriate combinations of logic gates, programmable gate arrays (PGAs), or field-programmable gate arrays (FPGAs). Embodiment 3 In this embodiment, to verify the beneficial effects of the present invention, scientific validation was conducted through economic benefit calculations and simulation experiments. The reference equipment parameters used in this embodiment are shown in Table 1. Table 1 - Reference Equipment Parameters for Embodiment Parameter Value ^GA 46.4 pH Lfi 22 pH fmin 79 kHz fmax 90 kHz f0 0.5 kHz fr 85.5 kHz ^max 840 V ^min 300 V rGA 0.04 Q t-CLYld max 0.4 In this embodiment, the power level is based on WPTI class, with PPP set to 3300 W. 1. Substitute the above parameters into the reference region and interoperability judgment criteria expressions in Step S3 of Embodiment 1. 2. Set the minimum test frequency fmtn, maximum test frequency fmax, and scanning step size f0. and obtain the frequency sequenceffy, / ^ —> fn}- 3. Operate the system to alter the inverter frequency of the ground reference device, initiate charging, and measure and record the impedance at the reference ground coil port to obtain the frequencyimpedance characteristics {Zv Z2,..., Zn). 4. Use the expressions for the reference region to plot the impedance test graph based on the measured frequency-impedance data. 5. Determine the interoperability and evaluate the interoperability level of the tested device based on the relative position of the measured impedance points with respect to the reference region and display the output. It should be noted that the above embodiment is provided for the purpose of illustrating the technical solution of the present invention and should not be construed as limiting. Although the present invention is described in detail with reference to preferred embodiments, those skilled in the art will understand that modifications or equivalent substitutions may be made to the technical solution without departing from the spirit and scope of the invention, and all such modifications or substitutions shall fall within the scope of protection defined by the claims of this invention.

Claims

1. A method for wireless charging interoperability testing based on frequency-impedance characteristics, comprising:- altering the operating frequency of a ground reference device inverter using a frequency sequence,- measuring and recording an impedance at the port of a ground reference coil and plotting an impedance test graph, and- determining whether a tested onboard device is interoperable and identifying its interoperability level based on the correlation between impedance scatter points and a reference region formed by four boundary curves.

2. A method according to claim 1, wherein: die step of altering the operating frequency of said ground reference device inverter comprises:- defining die lower and upper bounds of a test frequency as fmin and fmax^ respectively,- performing a frequency scan over the interval (fmin> fmax} with step size / 0, yielding said frequency sequence { / i, f2, ■■■, fn} ; its corresponding angular frequency sequence is {req, m2,..., con}, and- setting an operating frequency for said ground reference device inverter sequentially according to said frequency sequence.

3. A method according to claim 2, wherein: the step of measuring and recording said impedance at the port of said ground reference coil includes matching said tested onboard device with said ground reference device inverter, thereby obtaining said frequency-impedance characteristics sequence {Z1,Z2,..., Zn} of said tested onboard device; A reference frequency is defined as fr G { / j, / 2, ■ ■ ■, fn}, and the corresponding reference impedance is Zr G {Z1,Z2,..., Zn).

4. A method according to claim 3, wherein: said reference region is formed by four boundary7 curves: a lower boundary7, an upper boundary7, a left boundary, and a right boundaiy;said lower boundary is defined as:Im(Z) - mLga--------= tanU^nYRe(Z) - rGAwhere LGA is the self-inductance of said reference ground coil, rGA is the internal resistance of said reference ground coil, co is the angular frequency, 0max is the maximum allowable impedance angle for Zero-Voltage Switching during inverter operation, hn(Z) is the imaginary7 part of a measured impedance, and Re(Z) is the real part of said measured impedance;said upper boundary is defined as:Im(Z) = a)LGAsaid left boundary7 is defined as:pr / 2oumaxwhere is the inductance of the series compensation inductor on the ground reference device, Umax is the upper limit of the inverter input voltage of said ground reference device inverter, and P is the specified output power of said ground reference device inverter;said right boundary is defined as:Re(Z)RH2 oumin+ rGAwhere Umin is the lower limit of the input voltage of said ground reference device inverter.

5. A method according to claim 4, wherein: the step of determining whether said tested onboard device is interoperable includes:- If any point Zm in said frequency-impedance characteristics sequence lies within said reference region or a curve fitted to said frequency-impedance characteristics sequence intersects said reference region, then said tested onboard device meets interoperability test;said frequency-impedance characteristics sequence contains Zm, that satisfies:' n2o)2L^iPRe(Zm) <1— + rGAminn2G)2L2flP' Re^} >--2---+ rGAmaxIm(Zm) <^m^GAVlm(Zm) >-tanO^^Re^Z^ - rGA) + g^gaand said frequency-impedance characteristics sequence contains Zm and Zm+r that satisfy:G)mLGA)(jTfi(JZm+-^ G)m+yLGA) <0n2a)2LfAP n2a)2Lf-.P-----5--1- rGA <Re(Zm) <-----z--1- rGA01 / 2 v fill2 "uumax ^^minn2oj^+1L2flP , n2G)2n^L2nP ,"b rGA — (Zm. i 1 J — oji2 ^GAoUmaxwhere Zm and Zm+1 are two consecutive impedance values in said frequency-impedance characteristics sequence, and rnm, mm+1 are their respective angular frequencies.

6. A method according to claim 5, wherein: the interoperability level is determined as follows:- If said reference impedance Zr satisfies:Re(Zr) <n2 m2 L^P+ rGA' Re(Zr) >n2a)2L2^Pqij2 oumax+ rGAIm^Zy) <<t)rLGA< ImCZy) >—tan0max(Re(Zr) - rGA) + mrLGAthen said tested onboard device is classified as Class I interoperable, meaning it can operate with any device conforming to national standards;- If the above conditions are not met but interoperability is still observed, said tested onboard device is classified as Class II interoperable, indicating it can only work well with ground devices that support frequency adjustment.

7. A system for implementing the method of any one of claims 1 to 6, comprising: a power factor correction unit, a DC-DC buck converter, a frequency-adjustable inverter, a reference ground coil and compensation network, an impedance testing unit, and an information processing unit.

8. A system according to claim 7, wherein:- said power factor correction unit and said DC-DC converter supply a regulated DC input voltage;- said frequency-adjustable inverter provides high-frequency excitation within a defined frequency range;- said reference ground coil and compensation network transfer energy via electromagnetic coupling to the onboard device under test;- said impedance testing unit measures the impedance at the coil port under various frequencies; - said information processing unit analyses the sequence of measured impedance values to produce an interoperability test result.

9. A computer device comprising a memory and a processor, wherein said memory stores a computer program, and said processor executes said computer program to implement the steps according to any one of claims 1 to 7.

10. A computer-readable storage medium storing a computer program, wherein said program is executed by a processor to implement the steps according to any one of claims 1 to 7.PCT / CN2024 / 134761A. CLASSIFICATION OF SUBJECT MATTER G01R31 / 00(2006.01)i According to International Patent Classification (IPC) or to both national classification and IPC B. FIELDS SEARCHED Minimum documentation searched (classification system followed by classification symbols) IPC:G01R Documentation searched other than minimum documentation to the extent that such documents are included in the fields searched Electronic data base consulted during the international search (name of data base and, where practicable, search terms used) CNTXT, ENTXTC, CNKI, web of science: KHMK MOt iW. POM, ZZ, SXZ SJM, lEM, iiJ?, KM, iEH, SbK, electric vehicle, automobile, wireless charging, impedance, interoperability, authentication, match+, frequency, diagram, inverter, coil?, reference, boundary C. DOCUMENTS CONSIDERED TO BE RELEVANT Category* Citation of document, with indication, where appropriate, of the relevant passages Relevant to claim No. PX CN 118688535 A (ELECTRIC POWER RESEARCH INSTITUTE, GUANGXI POWER GRID CO., LTD.) 24 September 2024 (2024-09-24) description, paragraphs [0009]-[0088], and figures 1-3 1-10 X HASSLER, M. et al. "A Method for Interoperable Interface Description of Inductive Power Transfer Systems" 2018 IEEE PELS Workshop on Emerging Technologies: Wireless Power Transfer (WoW), 30 August 2018 (2018-08-30), pages 1-5 1-3, 7-10 A CN 110861509 A (TSINGHUA UNIVERSITY) 06 March 2020 (2020-03-06) entire document 1-10 A CN 111030763 A (HARBIN INSTITUTE OF TECHNOLOGY) 17 April 2020 (2020-04-17) entire document 1-10 A CN 114487667 A (CHINA UNIVERSITY OF MINING AND TECHNOLOGY) 13 May 2022 (2022-05-13) entire document 1-10 | | Further documents are listed in the continuation of Box C. | | See patent family annex. * Special categories of cited documents: “T” later document published after the international filing date or priority “A” document defining the general state of the art which is not considered date and not in conflict with the application but cited to understand the to be of particular- relevance principle or theory underlying the invention “D” document cited by the applicant in the international application “X” document of particular- relevance; the claimed invention cannot be “E” earlier application orpatent but published on or after the international considered novel or cannot be considered to involve an inventive step filing date when the document is taken alone “L” document which may throw doubts on priority claim(s) or which is “Y” document of particular relevance; the claimed invention cannot be cited to establish the publication date of another citation or other considered to involve an inventive step when the document is special reason (as specified) combined with one or more other such documents, such combination “O” document referring to an oral disclosure, use, exhibition or other being obvious to a person skilled in the art means document member of the same patent family “P” document published prior to the international filing date but later than the priority date claimed Date of the actual completion of the international search 17 January 2025 Date of mailing of the international search report 18 February 2025 Name and mailing address of the ISA / CN China National Intellectual Property Administration (ISA / CN) China No. 6, Xitucheng Road, Jimenqiao, Haidian District, Beijing 100088 Authorized officer Telephone No.PCT / CN2024 / 134761C. DOCUMENTS CONSIDERED TO BE RELEVANTCategory* Citation of document, with indication, where appropriate, of the relevant passages Relevant to claim No. A CN 109541341 A (STATE GRID CORPORATION OF CHINA et al.) 29 March 2019 (2019-03-29) 1-10 entire document A US 2013020862 Al (UT-BATTELLE, LLC) 24 January 2013 (2013-01-24) entire document 1-10 A (NIE, Yifan). 'WIWWBf Al (Research on Interoperability Test Method of Electric Vehicle Wireless Charging System Based on Impedance Parameters)" BS44t£nS (Chinese Master's Theses Full-Text Database, Engineering Science &Technology II), Vol. \, No. 03, 15 March 2022 (2022-03-15), ISSN: 1674-0246, pages 1-63 1-10INTERNATIONAL SEARCH REPORT Information on patent family membersInternational application No.PCT / CN2024 / 134761Patent document cited in search report Publication date (day / month / year) Patent family member, s) Publication date (day / month / year) CN 118688535 A 24 September 2024 None CN 110861509 A 06 March 2020 CN 110861509 B 06 March 2020 CN 111030763 A 17 April 2020 CN 111030763 B 13 August 2021 CN 114487667 A 13 May 2022 CN 114487667 B 08 November 2022 CN 109541341 A 29 March 2019 None US 2013020862 Al 24 January 2013 US 9221351 B2 29 December 2015 WO 2013012480 Al 24 January 2013 EP 2735085 Al 28 May 2014 EP 2735085 Bl 30 December 2020

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