Load parameter estimation method of magnetic coupling resonant wireless power transmission system

Abstract

The invention discloses a load parameter estimation method of a magnetic coupling resonant wireless power transmission system. The method comprises the following steps: when direct-current input voltage is converted into high-frequency alternating-current voltage through an inverter circuit to act on a resonant circuit and then supplies power to a load through a rectifier and filter circuit, acquiring a phase difference between a voltage vector and a current vector of a resonant cavity at a transmitting end, and judging whether the phase difference is zero or not, the resonant circuit comprises a transmitting end resonant cavity and a receiving end resonant cavity; and when the phase difference is not zero, the frequency of the switching tube driving signal is adjusted in real time according to the phase difference based on an automatic tuning technology until the phase difference between the voltage and the current of the transmitting end resonant cavity is zero. According to the invention, the technical problems of high cost, large electromagnetic interference, complex control method and limited working conditions of the load parameter estimation method of the magnetic coupling resonant wireless power transmission system in the prior art are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of wireless power transmission, and in particular to a load parameter estimation method for a magnetically coupled resonant wireless power transmission system. Background Art

[0002] Wireless power transmission technology can transfer electrical energy from the transmitter to the receiver without electrical connection. It is a technology that uses the characteristics of electromagnetic fields to transmit energy. Among them, magnetically coupled resonant wireless power transmission technology has high power and efficiency, and is widely used in electric vehicles, drones, biomedical equipment and other fields. However, in actual application scenarios, due to the electrical isolation between the transmitter and the receiver, the transmitter cannot directly obtain the voltage and current parameters of the load for closed-loop control. When the coil position or load impedance changes, the power of the power transmission will be unstable and the efficiency will decrease.

[0003] Therefore, how the transmitter can quickly and accurately obtain the load voltage and current parameters for closed-loop control to achieve efficient and stable transmission of electric energy is the key to the practical application of magnetically coupled resonant wireless power transmission systems.

[0004] According to the literature summary, the existing methods for obtaining load parameters at the transmitter end for magnetically coupled resonant wireless power transmission systems are mainly as follows: (1) Using wireless communication methods, the voltage and current parameters of the load are transmitted to the transmitter in real time through wireless communication; (2) Design the switching circuit topology, compare the circuit information fed back by different topologies, calculate the coil mutual inductance and load impedance, and estimate the load voltage and current parameters on the transmitter side; (3) Establish complex mathematical relationships to directly solve the loop equation or use iterative algorithms to estimate intermediate variables such as coil mutual inductance and load impedance, and then estimate the load voltage and current parameters. The entire process is completed on the transmitter side.

[0005] Among the above methods, method (1) has high accuracy and good real-time performance, but it adds a communication circuit, which increases the hardware cost of the system and also has the problem of electromagnetic interference; method (2) designs a switching circuit, which increases the hardware cost of the system and the control method is also relatively complex; method (3) has a lower cost, but has problems with limited working conditions or complex software algorithms. Summary of the invention

[0006] The embodiment of the present invention provides a load parameter estimation method for a magnetically coupled resonant wireless power transmission system, which at least solves the technical problems in the prior art of the load parameter estimation method for a magnetically coupled resonant wireless power transmission system, such as high cost, large electromagnetic interference, complex control method and limited working conditions.

[0007] According to one aspect of an embodiment of the present invention, a load parameter estimation method for a magnetically coupled resonant wireless power transmission system is provided. The method may include: when a DC input voltage is converted into a high-frequency AC voltage through an inverter circuit and acts on a resonant circuit, and then powers the load through a rectifier filter circuit, the phase difference between the voltage vector and the current vector of the transmitting end resonant cavity is collected, and it is determined whether the phase difference is zero, wherein the resonant circuit includes a transmitting end resonant cavity and a receiving end resonant cavity; when the phase difference is non-zero, the frequency of the switch tube drive signal is adjusted in real time according to the magnitude of the phase difference based on the automatic tuning technology until the phase difference between the voltage and current of the transmitting end resonant cavity is zero; when the phase difference is zero, the voltage effective value and the current effective value of the transmitting end resonant cavity are collected, and the voltage effective value and the current effective value are substituted into the loop equation to calculate the resonant mutual inductance of the resonant circuit and the load impedance of the receiving end; based on the resonant mutual inductance, the load impedance of the receiving end and the current modulus of the transmitting end resonant cavity, the voltage modulus and the current modulus of the load of the receiving end are obtained.

[0008] Optionally, the expression of the resonant mutual inductance of the resonant circuit is:

[0009] in, is the resonant mutual inductance of the resonant circuit, is the internal resistance of the transmitting coil of the transmitting end resonant cavity, is the self-inductance of the transmitting coil of the transmitting end resonant cavity, is the self-inductance of the receiving coil of the receiving end resonant cavity; is the mutual inductance between the transmitting coil and the receiving coil, is the resonant capacitor connected in series with the transmitting coil, is the resonant capacitor connected in series with the receiving coil, is the load impedance at the receiving end, is the effective value of the voltage of the transmitting end resonant cavity, is the effective value of the current in the transmitting end resonant cavity, is the angular frequency in the magnetic coupling resonant wireless power transmission system, and its relationship with the operating frequency of the magnetic coupling resonant wireless power transmission system is: , It is the operating frequency of the magnetically coupled resonant wireless power transmission system.

[0010] Optionally, the load impedance of the receiving end is expressed as:

[0011] in, is the load impedance at the receiving end, is the internal resistance of the receiving coil of the receiving end resonant cavity.

[0012] Optionally, the method of obtaining the voltage modulus and current modulus of the load at the receiving end based on the resonant mutual inductance, the load impedance at the receiving end and the current modulus of the resonant cavity at the transmitting end includes: substituting the resonant mutual inductance and the load impedance at the receiving end into the loop equation to obtain the current transfer coefficient; obtaining the current modulus of the load at the receiving end based on the current transfer coefficient and the current modulus of the resonant cavity at the transmitting end; and obtaining the voltage modulus of the load at the receiving end based on the current modulus of the load at the receiving end and the load impedance at the receiving end.

[0013] Optionally, the expression of the current transfer coefficient is:

[0014] in, is the current transfer coefficient.

[0015] Optionally, the expression for obtaining the current modulus value of the load at the receiving end based on the current transfer coefficient and the current modulus value of the transmitting end resonant cavity is:

[0016] in, is the current modulus of the load at the receiving end, is the current modulus of the transmitting end resonant cavity.

[0017] Optionally, the expression for obtaining the voltage modulus of the load at the receiving end based on the current modulus of the load at the receiving end and the load impedance at the receiving end is:

[0018] in, is the voltage modulus of the load at the receiving end.

[0019] Beneficial effects of the invention: The invention proposes a load parameter estimation method for a magnetically coupled resonant wireless power transmission system, which adjusts the operating frequency in real time according to the phase difference between the voltage and current in the resonant cavity of the transmitter, keeps the phase of the voltage and current in the resonant cavity of the transmitter consistent, and puts the system in a resonant state. The load voltage and current parameters are estimated by solving the loop equation in the resonant state. The invention is simple and intuitive, easy to understand, does not require communication between the transmitter and the receiver, reduces hardware costs, avoids electromagnetic interference problems, and has high accuracy and strong real-time performance, which is convenient for engineering applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings: Figure 1is a flow chart of a load parameter estimation method for a magnetically coupled resonant wireless power transmission system according to an embodiment of the present invention; Figure 2 is a block diagram of a magnetically coupled resonant wireless power transmission system according to an embodiment of the present invention; Figure 3 4 is a schematic diagram of a magnetically coupled resonant wireless power transmission system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0021] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only embodiments of a part of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0022] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and to describe a specific order or sequence. It should be understood that the terms used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0023] Example 1 According to an embodiment of the present invention, a load parameter estimation method for a magnetically coupled resonant wireless power transmission system is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system comprising at least one set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in an order different from that shown here.

[0024] Figure 1 is a flow chart of a load parameter estimation method for a magnetically coupled resonant wireless power transmission system according to an embodiment of the present invention. Figure 1 As shown, the method comprises the following steps: Step S101, when the DC input voltage is converted into a high-frequency AC voltage through an inverter circuit and acts on the resonant circuit, and then powers the load through a rectifier and filter circuit, the phase difference between the voltage vector and the current vector of the transmitting end resonant cavity is collected, and it is determined whether the phase difference is zero, wherein the resonant circuit includes the transmitting end resonant cavity and the receiving end resonant cavity.

[0025] In this embodiment, if Figure 2 As shown, Figure 2 is a block diagram of a magnetically coupled resonant wireless power transmission system according to an embodiment of the present invention, in which a DC input voltage is converted into a high-frequency AC voltage through an inverter circuit and acts on a resonant circuit, and a receiving end supplies power to a load through a rectifier and filter circuit. Figure 3 is a schematic diagram of a magnetically coupled resonant wireless power transmission system according to an embodiment of the present invention. Figure 3 As shown, the phase detection processes the voltage vector and the current vector of the transmitting end resonant cavity to obtain the phase difference between the voltage vector and the current vector of the transmitting end resonant cavity. The phase detection includes a comparator and an XOR gate circuit.

[0026] Step S102, when the phase difference is non-zero, the frequency of the switch tube driving signal is adjusted in real time according to the phase difference based on the automatic tuning technology until the phase difference between the voltage and current of the transmitting end resonant cavity is zero.

[0027] In this embodiment, when the phase difference is not zero, as Figure 2 and Figure 3 As shown, based on the automatic tuning technology, the frequency of the switch tube drive signal is adjusted in real time according to the size of the phase difference, that is, the operating frequency of the magnetically coupled resonant wireless power transmission system is adjusted until the phase difference between the voltage vector and the current vector of the transmitting end resonant cavity is determined to be zero.

[0028] Step S103, when the phase difference is zero, collect the voltage effective value and the current effective value of the transmitting end resonant cavity, substitute the voltage effective value and the current effective value into the loop equation to calculate the resonant mutual inductance of the resonant loop and the load impedance of the receiving end.

[0029] In this embodiment, when the phase difference is zero, the voltage effective value and the current effective value of the transmitting end resonant cavity are collected, and the voltage effective value and the current effective value are substituted into the loop equation to obtain the resonant mutual inductance of the resonant loop and the load impedance of the receiving end, wherein the loop equation is: .

[0030] Step S104, obtaining a voltage modulus and a current modulus of a load at the receiving end based on the resonant mutual inductance, the load impedance at the receiving end, and the current modulus of a resonant cavity at the transmitting end.

[0031] In this embodiment, the resonant mutual inductance, the load impedance of the receiving end and the current modulus of the resonant cavity of the transmitting end are calculated to obtain the voltage modulus and current modulus of the load at the receiving end. It should be noted that the voltage modulus and current modulus of the load at the receiving end are also load parameters.

[0032] The above method of this embodiment is further introduced below.

[0033] As an optional implementation manner, in step S103, the expression of the resonant mutual inductance of the resonant circuit is:

[0034] in, is the resonant mutual inductance of the resonant circuit, is the internal resistance of the transmitting coil of the transmitting end resonant cavity, is the self-inductance of the transmitting coil of the transmitting end resonant cavity, is the self-inductance of the receiving coil of the receiving end resonant cavity; is the mutual inductance between the transmitting coil and the receiving coil, is the resonant capacitor connected in series with the transmitting coil, is the resonant capacitor connected in series with the receiving coil, is the load impedance at the receiving end, is the effective value of the voltage of the transmitting end resonant cavity, is the effective value of the current in the transmitting end resonant cavity, is the angular frequency in the magnetic coupling resonant wireless power transmission system, and its relationship with the operating frequency of the magnetic coupling resonant wireless power transmission system is: , It is the operating frequency of the magnetically coupled resonant wireless power transmission system.

[0035] In this embodiment, the effective value of the voltage and the effective value of the current of the transmitting end resonant cavity are substituted into the loop equation for deduction to obtain the resonant mutual inductance of the resonant loop.

[0036] As an optional implementation manner, in step S103, the expression of the load impedance of the receiving end is:

[0037] in, is the load impedance at the receiving end, is the internal resistance of the receiving coil of the receiving end resonant cavity.

[0038] In this embodiment, the voltage effective value and the current effective value of the resonant cavity at the transmitting end are substituted into the loop equation for deduction to obtain the load impedance at the receiving end.

[0039] As an optional implementation method, step S104, the voltage modulus and current modulus of the load at the receiving end are obtained based on the resonant mutual inductance, the load impedance at the receiving end and the current modulus of the resonant cavity at the transmitting end, including: substituting the resonant mutual inductance and the load impedance at the receiving end into the loop equation to obtain the current transfer coefficient; obtaining the current modulus of the load at the receiving end based on the current transfer coefficient and the current modulus of the resonant cavity at the transmitting end; obtaining the voltage modulus of the load at the receiving end based on the current modulus of the load at the receiving end and the load impedance at the receiving end.

[0040] In this embodiment, the resonant mutual inductance and the load impedance of the receiving end are substituted into the loop equation for derivation to obtain the current transfer coefficient, the current transfer coefficient and the current modulus of the resonant cavity of the transmitting end are multiplied to obtain the current modulus of the load at the receiving end, and the current modulus of the load at the receiving end is multiplied by the load impedance of the receiving end to obtain the voltage modulus of the load at the receiving end.

[0041] As an optional embodiment, the expression of the current transfer coefficient is:

[0042] in, is the current transfer coefficient.

[0043] In this embodiment, the resonant mutual inductance and the load impedance are substituted into the loop equation for derivation to obtain the current transfer coefficient.

[0044] As an optional embodiment, the expression for obtaining the current modulus value of the load at the receiving end based on the current transfer coefficient and the current modulus value of the transmitting end resonant cavity is:

[0045] in, is the current modulus of the load at the receiving end, is the current modulus of the transmitting end resonant cavity.

[0046] In this embodiment, the current transfer coefficient and the current modulus of the transmitting end resonant cavity are multiplied to obtain the current modulus of the load at the receiving end.

[0047] As an optional embodiment, the expression for obtaining the voltage modulus of the load at the receiving end based on the current modulus of the load at the receiving end and the load impedance at the receiving end is:

[0048] in, is the voltage modulus of the load at the receiving end.

[0049] In this embodiment, the current modulus of the load at the receiving end and the load impedance at the receiving end are multiplied to obtain the voltage modulus of the load at the receiving end.

[0050] The parameters of the magnetically coupled resonant wireless power transmission system of the present invention are: the self-inductance of the transmitting coil of the transmitting end resonant cavity The inductance is 68.6uH, and its internal resistance is measured For 47 , the self-inductance of the receiving coil of the receiving end resonant cavity The inductance is 68.9uH, and its internal resistance is measured For 48 , the resonant capacitor connected in series with the transmitting coil The capacitance is 22.3nF, and the resonant capacitor connected in series with the receiving coil The capacitance is 21nF, and the output voltage of the DC power supply is After being converted into a high-frequency AC voltage through a full-bridge inverter as the input of the transmitter's resonant cavity, the electric energy is transferred to the receiving end by utilizing the magnetic coupling resonance principle, and the receiving end supplies power to the load through a rectifier and filter circuit; wherein, the phase detection unit of the transmitting end is composed of a comparator and an XOR gate circuit, and the voltage and current signals of the transmitter's resonant cavity are subjected to zero-crossing comparison by the comparator to obtain zero-crossing comparison signals of the voltage and current respectively, and the phase difference of the voltage and current is obtained after performing an XOR operation on the two zero-crossing comparison signals and sent to a single-chip microcomputer (Microcontroller Unit, referred to as MCU for short), and the MCU adjusts the operating frequency of the switch tube to make the voltage and current phases of the transmitter's resonant cavity consistent, and then calculates the coil mutual inductance and load impedance according to the calculation expression provided by the present invention, and then estimates the voltage modulus and current modulus of the load at the receiving end.

[0051] The load parameters are estimated for the method of the present invention as follows.

[0052] Load selection load is 5 , 10 and 25 The input voltage is 30V, the transmitting coil and the receiving coil are in facing position, and only radial offset is performed, the offset distance is 1cm to 13cm; Table 1-3 gives the comparison between the actual voltage and current values ​​and the estimated voltage and current values ​​under different load resistances. It can be seen from the results that the estimation error does not exceed 10%, the mean square error of the estimation result does not exceed 0.98, and the mean absolute percentage error does not exceed 6.79%.

[0053] It can be seen from the implementation examples that when the transmitter of the magnetic coupling resonant wireless power transmission system performs closed-loop control, the method proposed in the present invention is used to estimate the load voltage and current parameters. The process is simple, the estimation error is low, no communication is required, and the hardware cost of the circuit is reduced.

[0054] Table 15 Comparison of estimated and actual load resistance values

[0055] Table 210 Comparison of estimated and actual load resistance values

[0056] Table 325 Comparison of estimated and actual load resistance values

[0057] In an embodiment of the present invention, when a DC input voltage is converted into a high-frequency AC voltage through an inverter circuit and acts on a resonant circuit, and then powers a load through a rectifier and filter circuit, the phase difference between the voltage vector and the current vector of the transmitting end resonant cavity is collected, and it is determined whether the phase difference is zero, wherein the resonant circuit includes a transmitting end resonant cavity and a receiving end resonant cavity; when the phase difference is non-zero, the frequency of the switch tube drive signal is adjusted in real time according to the size of the phase difference based on the automatic tuning technology until the phase difference between the voltage and current of the transmitting end resonant cavity is zero; when the phase difference is zero, the voltage effective value and the current effective value of the transmitting end resonant cavity are collected, and the voltage effective value and the current effective value are converted into the value of the voltage effective value and the current effective value. The values ​​are substituted into the loop equation to calculate the resonant mutual inductance of the resonant loop and the load impedance of the receiving end; based on the resonant mutual inductance, the load impedance of the receiving end and the current modulus of the resonant cavity of the transmitting end, the voltage modulus and current modulus of the load of the receiving end are obtained, which solves the technical problems of high cost, large electromagnetic interference, complex control method and limited working conditions of the load parameter estimation method of the magnetic coupling resonant wireless power transmission system in the prior art, and achieves the technical effect that the present invention is simple and intuitive, easy to understand, does not require communication between the transmitting end and the receiving end, reduces hardware costs, avoids electromagnetic interference problems, has high accuracy and strong real-time performance, and is convenient for engineering applications.

[0058] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0059] In the above embodiments of the present invention, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0060] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only schematic. For example, the division of units can be a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of units or modules, which can be electrical or other forms.

[0061] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed over multiple units. Some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0062] In addition, each functional unit in each embodiment of the present invention may be integrated into a first processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0063] The above are only preferred embodiments of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for estimating load parameters of a magnetically coupled resonant wireless power transmission system, characterized in that: include: When the DC input voltage is converted into a high-frequency AC voltage through an inverter circuit and acts on the resonant circuit, and then powers the load through a rectifier and filter circuit, the phase difference between the voltage vector and the current vector of the transmitting end resonant cavity is collected, and it is determined whether the phase difference is zero, wherein the resonant circuit includes the transmitting end resonant cavity and the receiving end resonant cavity; When the phase difference is non-zero, the frequency of the switch tube drive signal is adjusted in real time according to the phase difference based on the automatic tuning technology until the phase difference between the voltage and current of the transmitting end resonant cavity is zero; When the phase difference is zero, collect the voltage RMS value and current RMS value of the resonant cavity at the transmitting end, substitute the voltage RMS value and current RMS value into the loop equation to calculate the resonant mutual inductance of the resonant loop and the load impedance of the receiving end; Based on the resonant mutual inductance, the load impedance of the receiving end and the current modulus of the resonant cavity of the transmitting end, the voltage modulus and the current modulus of the load of the receiving end are obtained.

2. The method according to claim 1, characterized in that: The expression of the resonant mutual inductance of the resonant circuit is: in, is the resonant mutual inductance of the resonant circuit, is the internal resistance of the transmitting coil of the transmitting end resonant cavity, is the self-inductance of the transmitting coil of the transmitting end resonant cavity, is the self-inductance of the receiving coil of the receiving end resonant cavity; is the mutual inductance between the transmitting coil and the receiving coil, is the resonant capacitor connected in series with the transmitting coil, is the resonant capacitor connected in series with the receiving coil, is the load impedance at the receiving end, is the effective value of the voltage of the transmitting end resonant cavity, is the effective value of the current in the transmitting end resonant cavity, is the angular frequency in the magnetic coupling resonant wireless power transmission system, and its relationship with the operating frequency of the magnetic coupling resonant wireless power transmission system is: , It is the operating frequency of the magnetically coupled resonant wireless power transmission system.

3. The method according to claim 2, characterized in that The expression of the load impedance of the receiving end is: in, is the load impedance at the receiving end, is the internal resistance of the receiving coil of the receiving end resonant cavity.

4. The method according to claim 3, characterized in that The method of obtaining the voltage modulus and current modulus of the load at the receiving end based on the resonant mutual inductance, the load impedance at the receiving end and the current modulus of the resonant cavity at the transmitting end includes: Substituting the resonant mutual inductance and the load impedance at the receiving end into the loop equation, we get the current transfer coefficient; Based on the current transfer coefficient and the current modulus of the transmitting end resonant cavity, the current modulus of the load at the receiving end is obtained; Based on the current modulus of the load at the receiving end and the load impedance at the receiving end, a voltage modulus of the load at the receiving end is obtained.

5. The method according to claim 4, characterized in that The expression of the current transfer coefficient is: in, is the current transfer coefficient.

6. The method according to claim 5, characterized in that The expression for obtaining the current modulus value of the load at the receiving end based on the current transfer coefficient and the current modulus value of the transmitting end resonant cavity is: in, is the current modulus of the load at the receiving end, is the current modulus of the transmitting end resonant cavity.

7. The method according to claim 6, characterized in that The expression for obtaining the voltage modulus of the load at the receiving end based on the current modulus of the load at the receiving end and the load impedance at the receiving end is: in, is the voltage modulus of the load at the receiving end.

8. A computer system, characterized in that include: One or more processors, and a computer-readable storage medium for storing one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors are enabled to implement the method of claim 1.

9. A computer-readable storage medium, characterized in that Computer executable instructions are stored, and when the instructions are executed, they are used to implement the method of claim 1.

10. A computer program product, characterized in that The invention comprises computer executable instructions, which are used to implement the method of claim 1 when being executed.

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