Coordinated Frequency Support Control Method, Device and Control System for Wind Power Energy Storage System

Abstract

The present invention discloses a collaborative frequency support control method, device and control system for a wind power energy storage system, belonging to the field of new energy power generation control technology. In the process of collaborative frequency support control of a wind farm group, if the torque of some wind turbines exceeds the limit, then some wind turbines are switched from collaborative frequency support control to torque limit control; then, the difference between the power reference value corresponding to the collaborative frequency support control of the wind farm group and the power reference value corresponding to the torque limit control of some of the wind turbines is calculated; and the difference of the power reference value is allocated to each energy storage device in the wind power energy storage system, so that each energy storage device uses the allocated power quota as the reference power for frequency support. The present invention integrates the advantages of wind farm collaborative control and torque limit control, can not only achieve a high utilization rate of frequency modulation resources in the wind farm, but also ensure torque safety, and can achieve a better full limit support effect.

Description

Technical Field

[0001] The present invention belongs to the technical field of new energy power generation control, and more specifically, relates to a cooperative frequency support control method, device and control system for a wind power energy storage system. Background Art

[0002] In recent years, wind power has received extensive global attention as a clean energy source. With the large-scale integration of wind power, traditional synchronous machines have been replaced, resulting in a decrease in system inertia and posing a severe challenge to the system frequency stability. Therefore, many countries have proposed in grid codes that wind power needs to have the ability to actively participate in system frequency regulation. Wind farms provide frequency support mainly through rotor kinetic energy control and load shedding control. Load shedding control will directly cause wind curtailment in wind farms and reduce system economy. Rotor kinetic energy control can be adopted when the wind turbine operates under maximum power tracking control, and the rotor kinetic energy stored in the wind turbine is released to participate in system frequency support. Existing scholars have maximized the utilization of the rotor kinetic energy of wind turbines by coordinating each unit within the wind farm.

[0003] In a power system with wind power, the use of energy storage to assist system frequency regulation can enable the energy storage to flexibly absorb and release active power. Therefore, in addition to using the adjustment ability of wind turbines themselves, energy storage such as flywheels, batteries, and supercapacitors can be added to assist wind turbines in participating in frequency regulation.

[0004] However, in the current complex AC system with multiple energy storage devices and wind turbines, how to efficiently and stably perform frequency support when a load mutation event occurs is an urgent problem to be solved. Summary of the Invention

[0005] In view of the above deficiencies or improvement requirements of the prior art, the present invention provides a cooperative frequency support control method, device and control system for a wind power energy storage system, aiming to solve the technical problem of how to efficiently and stably perform frequency support, which is an urgent problem to be solved.

[0006] To achieve the above object, according to one aspect of the present invention, a cooperative frequency support control method for a wind power energy storage system is provided, including:

[0007] S1: When a load mutation event occurs in the wind power energy storage system, start the wind farm group in the wind power energy storage system for cooperative frequency support control;

[0008] S2: During the process of the wind farm group performing cooperative frequency support control, if the torque of some wind turbines exceeds the limit, switch the part of the wind turbines from cooperative frequency support control to torque limit control;

[0009] S3: Calculate the difference between the power reference value corresponding to the wind farm group performing cooperative frequency support control and the power reference value corresponding to some wind turbines performing torque limit control;

[0010] S4: Allocate the difference of the power reference value to each energy storage device in the wind power energy storage system, and control each energy storage device to use the allocated power amount as the reference power for frequency support.

[0011] In one embodiment, S3 includes:

[0012] Use the formula to calculate the difference of the power reference value;

[0013] where m is the serial number of the wind turbine with torque exceeding the limit; k is the total number of wind turbines with torque exceeding the limit, n is the total number of wind turbines, P sref,m (t) is the output power reference value of the mth wind turbine during coordinated frequency support control, P TLC,m (t) is the power reference value of the mth wind turbine during torque limit control, P x,m (t) is the difference of the power reference value corresponding to the mth wind turbine.

[0014] In one embodiment, S4 includes:

[0015] S41: Allocate the difference of the power reference value to the corresponding energy storage device according to the charge state of each energy storage device;

[0016] S42: Control each energy storage device to use the allocated power amount as the reference power for frequency support.

[0017] In one embodiment, S41 includes:

[0018] Use the formula to allocate the power amount for each energy storage device; where P ESS,j (t) is the output power reference value of the jth energy storage device during frequency support, SOC 0,j is the initial charge state of the jth energy storage device; m is the serial number of the wind turbine with torque exceeding the limit; k is the total number of wind turbines with torque exceeding the limit, P x,m (t) is the difference of the power reference value of the mth wind turbine.

[0019] In one embodiment, the judgment condition for the torque of the wind turbine exceeding the limit in S2 is: if the electromagnetic torque T of a certain wind turbine e is greater than the torque threshold, it is considered that the torque of the wind turbine exceeds the limit.

[0020] In one embodiment, after S4, it further includes:

[0021] When the grid frequency on the grid connection bus of the wind power cluster reaches the lowest point, it remains for a first preset time; after reaching the first preset time, the rotational speed of the wind turbines is restored according to a preset curve.

[0022] In one embodiment, after the S4, it further includes:

[0023] When it is detected that the output power of the energy storage device reaches the maximum value, it remains for a second preset time; after reaching the second preset time, the power recovery slope of each energy storage device is set according to the initial charge state, and the output power at this stage is: P ESS,j (t) = P ESS,j (t p ) + k st ·k soc ·t;

[0024] Wherein, P ESS,j (t) is the output power of the j-th energy storage device at the current moment t, P ESS,j (t p ) is the output power of the j-th energy storage device at the moment t when the output power is the largest p corresponding to, k st is the inherent recovery slope, k soc is the adaptive recovery slope, k soc is proportional to the SOC of the energy storage device.

[0025] According to another aspect of the present invention, a coordinated frequency support control device for a wind power energy storage system is provided, including:

[0026] A start module, configured to start the wind farm cluster in the wind power energy storage system for coordinated frequency support control when a load mutation event occurs in the wind power energy storage system;

[0027] A switching module, configured to switch a part of the wind turbines from coordinated frequency support control to torque-limiting control if torque overlimit occurs in some of the wind turbines during the process of coordinated frequency support control of the wind farm cluster;

[0028] A calculation module, configured to calculate the difference between the power reference value corresponding to the coordinated frequency support control of the wind farm cluster and the power reference value corresponding to torque-limiting control of some of the wind turbines;

[0029] A support module, configured to distribute the difference of the power reference value to each energy storage device in the wind power energy storage system, and control each of the energy storage devices to use the allocated power quota as the reference power for frequency support.

[0030] According to another aspect of the present invention, there is provided a control system for a wind power energy storage system, including a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, the steps of the method are implemented.

[0031] According to another aspect of the present invention, there is provided a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the method are implemented.

[0032] Generally speaking, compared with the prior art by the above technical solutions conceived by the present invention, the following beneficial effects can be achieved:

[0033] (1) The present invention provides a coordinated frequency support control method for a wind power energy storage system. During the coordinated frequency support control process of a wind farm group, if the torque of some wind turbines exceeds the limit, then switch the part of the wind turbines from coordinated frequency support control to torque limit control; then calculate the difference between the power reference value corresponding to the coordinated frequency support control of the wind farm group and the power reference value corresponding to the torque limit control of some of the wind turbines; allocate the difference of the power reference value to each energy storage device in the wind power energy storage system, so that each energy storage device uses the allocated power quota as the reference power for frequency support. The present invention integrates the advantages of wind farm coordinated control and torque limit control, can not only achieve high utilization rate of frequency modulation resources in the wind farm, but also ensure torque safety, and can achieve a better limit support effect.

[0034] (2) This solution uses the formula to calculate the difference of the power reference value; directly calculate the output power of the wind turbines with torque exceeding the limit before and after switching the support scheme, with low calculation complexity and simple operation.

[0035] (3) This solution allocates the difference of the power reference value to the corresponding energy storage device according to the state of charge of each energy storage device. Considering the wake effect of the wind farm and the state of charge of multiple energy storage devices, the frequency support effect is good, and the frequency deterioration can be suppressed in the early stage of frequency disturbance.

[0036] (4) This solution uses the formula to allocate the power quota for each energy storage device; among the energy storage devices, the total energy storage power reference value is allocated to each device according to the state of charge of the energy storage device, effectively avoiding the state of charge of the energy storage exceeding the limit; using the energy of the energy storage battery to make up for the wind power shortage caused by torque limit control, avoiding the support effect from becoming too poor due to the decrease in output power caused by the torque limit of the wind turbines.

[0037] (5) The judgment condition for the torque of the wind turbines to exceed the limit in this solution is: if the electromagnetic torque T of a certain wind turbine eIf the torque is greater than the torque threshold, it is considered that the torque of the fan exceeds the limit. Specifically, the switching judgment condition is: T e >1.15 p.u. This judgment method is simple and accurate.

[0038] (6) In the power maintenance and power recovery stages of the fan designed in this solution, when the grid frequency on the grid connection bus of the wind power group reaches the lowest point, it remains for the first preset time; after reaching the first preset time, the fan speed is restored according to a preset curve for the fan, which can increase the operation stability of the wind power energy storage system.

[0039] (7) In the power maintenance and power recovery stages of the energy storage device designed in this solution, when it is detected that the output power of the energy storage device reaches the maximum value, it remains for the second preset time. After reaching the second preset time, the power recovery slope of each energy storage device is set according to the initial charge state, which can increase the operation stability of the wind power energy storage system. Description of the Drawings

[0040] Figure 1 It is a flowchart of a collaborative frequency support control method for a wind power energy storage system provided in Embodiment 1 of the present invention;

[0041] Figure 2 It is a collaborative frequency support control block diagram for a wind farm provided in Embodiment 1 of the present invention;

[0042] Figure 3 It is a collaborative frequency support control block diagram for energy storage provided in Embodiment 1 of the present invention;

[0043] Figure 4 It is a topology diagram of the wind power and energy storage integrated into a four-machine two-area system provided in Embodiment 1 of the present invention;

[0044] Figure 5 It is a schematic diagram of various frequency support control methods and descriptions provided in Embodiment 1 of the present invention;

[0045] Figure 6 It is a schematic diagram of a frequency response curve provided in Embodiment 1 of the present invention;

[0046] Figure 7a It is a schematic diagram of a power-speed curve under ADC control;

[0047] Figure 7b It is a schematic diagram of a power-speed curve under WECC control;

[0048] Figure 8a It is a schematic diagram of the energy storage charge state under WECC control;

[0049] Figure 8b It is a schematic diagram of the energy storage output power under WECC control. Detailed Implementation Manner

[0050] In order to make the objectives, technical solutions and advantages of the present invention more clear and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0051] Embodiment 1

[0052] Referring to Figure 1 、 Figure 2 and Figure 3 , the present invention provides a collaborative frequency support control method for a wind power energy storage system, including: S1 - S4.

[0053] S1: When a load mutation event occurs in the wind power energy storage system, start the wind farm group in the wind power energy storage system for collaborative frequency support control; S2: During the process of the wind farm group performing collaborative frequency support control, if the torque of some wind turbines exceeds the limit, switch some wind turbines from collaborative frequency support control to torque limit control; S3: Calculate the difference between the power reference value corresponding to the wind farm group performing collaborative frequency support control and the power reference value corresponding to some of the wind turbines performing torque limit control; S4: Allocate the difference in power reference values to each energy storage device in the wind power energy storage system, and control each energy storage device to use the allocated power amount as the reference power for frequency support.

[0054] As an optional implementation manner, S1 can perform the following steps: detect the grid frequency on the grid connection bus of the wind farm in real time, determine whether a load mutation event occurs in the AC system, and start the collaborative frequency support control of the wind farm group after determining that the event occurs.

[0055] Among them, the judgment condition for a load mutation event to occur is:

[0056] f ≤ 49.98 Hz or f ≥ 50.02 Hz;

[0057] f is the grid frequency detected on the grid connection bus of the wind farm.

[0058] Specifically, in S1, after the frequency event occurs, start the collaborative frequency support control of the wind farm group, and this control is implemented using a leaderless consensus algorithm.

[0059] Define the consensus factor x of each wind turbine in the system i as:

[0060]

[0061] Among them, ω r,max and ω r,minrespectively represent the maximum and minimum limits of the rotor speed of the wind turbine generator set, generally taking 1.2 p.u. and 0.7 p.u. under normal circumstances; ω r,i represents the real-time speed of the wind turbine rotor; ω r,i0 represents the initial speed of the wind turbine rotor. This state index has a clear physical meaning and reflects the deviation of the current operating state of each wind turbine from its original initial state.

[0062] Specifically, in S1, the reference power value P sref,m for each wind turbine in the system is:

[0063]

[0064] where k opt is the MPPT fitting coefficient, and ΔP ref (t) is the reference power under the coordinated control of the wind turbines.

[0065] Specifically, the reference power ΔP ref (t) under the coordinated control of the wind turbines is:

[0066] ΔP ref (t) = ΔP ref1,m (t) + ΔP w1,m (t);

[0067] where ΔP ref1,m (t) is the reference power of the wind turbine state under the consistency control, and ΔP w1,m (t) is the droop reference power of the wind turbine.

[0068] As an optional implementation manner, S2 can perform the following steps: when the torque of the units in the wind farm exceeds the limit, switch the frequency support control of the wind turbine to torque limit control; if the torque of some units exceeds the limit, then when the torque reaches the threshold, switch the control of the unit to torque limit control, and the switching judgment condition is:

[0069] T e > 1.15 p.u. where T e is the electromagnetic torque of the wind turbine.

[0070] As an optional implementation manner, S3 can perform the following steps: when the torque of the wind turbine generator set exceeds the limit, start to calculate the difference in the power reference values between the coordinated frequency support control and the torque limit control of the wind farm group:

[0071]

[0072] where P TLC,m (t), P x,m(t) is the power reference value after the single wind turbine unit switches to torque limit control. M is the wind turbine number, n is the total number of wind turbines, i is the starting number of the torque - limited wind turbine units, and k is the ending number of the torque - limited wind turbine units.

[0073] As an optional implementation, S4 can perform the following steps: Distribute it proportionally to each energy storage device according to the charge state of the energy storage device, and this value is used as the reference power for the energy storage to participate in frequency support.

[0074] Furthermore, distribute P x,m (t) proportionally to each energy storage device according to the charge state of the energy storage device, and this value is used as the reference power for the energy storage to participate in frequency support

[0075]

[0076] Among them, P ESS,j (t) is the output power reference value when the j - th energy storage device performs frequency support, SOC 0,j is the initial charge state of the j - th energy storage device; m is the wind turbine number where torque limit occurs; k is the total number of wind turbines where torque limit occurs, and P x,m (t) is the difference in the power reference value of the m - th wind turbine.

[0077] As an optional implementation, after the S4, it further includes: When the grid frequency on the grid connection bus of the wind power group reaches the lowest point, maintain for a first preset time; after reaching the first preset time, perform the wind turbine speed recovery according to a preset curve for the wind turbines.

[0078] Specifically, after detecting that the system frequency reaches the lowest point, delay for 10 s, and perform the wind turbine speed recovery according to a preset curve. Set the expression of the wind turbine output power reference value in the speed recovery stage as follows:

[0079]

[0080] Among them, t1 is the moment of entering the speed recovery stage; Δt r is the total time of the entire speed recovery process, which is taken as 15 s here; ΔP s2,i (t 1 ) is the reference power of the wind turbine unit in the speed recovery stage; ΔP w,i (t 1 ) is the reference power of the wind farm at the moment of entering the speed recovery stage.

[0081] As an optional implementation, after the S4, it further includes:

[0082] After detecting that the output power of the energy storage device reaches the maximum value and maintaining it for a second preset time, after reaching the second preset time, set the power recovery slope of each energy storage device according to the initial charge state. The output power at this stage is: P ESS,j (t) = P ESS,j (t p ) + k st ·k soc ·t;

[0083] Specifically, after detecting that the output power of each energy storage device reaches the maximum value, sample and hold for a period of time. The output power at this stage is: max(P ESS,m (t)) = P ESS,m (t p ); t p is the moment when the maximum power output of the energy storage is detected. Then, set the power recovery slope of each energy storage device according to the initial charge state SOC 0,m . The output power at this stage is:

[0084] P ESS,m (t) = P ESS,m (t p ) + k st ·k soc ·t t > t p + 20s;

[0085] Among them, k st is the inherent recovery slope, and k soc is the adaptive recovery slope, and this value is proportional to the SOC of the energy storage device.

[0086] In order to verify the technical effect of the control method provided by the present invention, a simulation experiment is carried out on the IEEE standard four-machine two-area system model including wind power and energy storage by using the MATLAB / Simulink platform. The model is as Figure 4 shown, and the system parameters all use their built-in parameters without modification. The energy storage capacity is 5% of the wind turbine capacity.

[0087] Set a sudden load increase accident of 600MW at bus 7 at 5s, and several comparison control methods are as Figure 5 shown.

[0088] The frequency response results are as Figure 6As shown, it can be seen that the WECC method proposed by the present invention maximally improves the lowest frequency point, and has the best frequency support effect. The energy storage power release amount is the largest under the WECC method. Due to torque limitation in the TLC control, the wind power output decreases, the support effect is worse than that of the ADC, and SFD is caused due to the sudden power drop during the rotational speed recovery stage. The WECC method adds energy storage control on the basis of the TLC method, makes up for the power shortage, and improves the lowest frequency point. Under the CCS control, the energy storage is only used to alleviate the secondary frequency dip, and the lowest frequency point is not improved.

[0089] The fan torque responses of the WECC method and the TLC method are as Figure 7a and Figure 7b shown, where Figure 7a is the power - rotational speed curve under the ADC control, Figure 7b is the power - rotational speed curve under the WECC control. It can be seen that the torque - limiting control adopted in the WECC method can ensure that the torque does not exceed the limit during the support process.

[0090] The SOC state and output power of the energy storage under the WECC method are as Figure 8a and Figure 8b shown, Figure 8a is the energy storage charge state under the WECC control, Figure 8b is the energy storage output power under the WECC control. It can be seen that during the frequency support process, both the SOC and the output power adaptively change according to the initial SOC values of each device, and there is no over - limit throughout the process, ensuring safety and economy.

[0091] Embodiment 2

[0092] This embodiment provides a coordinated frequency support control device for a wind power energy storage system, including:

[0093] A start - up module, configured to start the wind farm group in the wind power energy storage system for coordinated frequency support control when a load mutation event occurs in the wind power energy storage system;

[0094] A switching module, configured to switch the part of the fans from coordinated frequency support control to torque - limiting control if torque over - limit occurs in some of the fans during the process of coordinated frequency support control of the wind farm group;

[0095] A calculation module, configured to calculate the difference between the power reference value corresponding to the coordinated frequency support control of the wind farm group and the power reference value corresponding to the torque - limiting control of some of the fans therein;

[0096] A support module, configured to distribute the difference of the power reference value to each energy storage device in the wind power energy storage system, and control each energy storage device to use the allocated power amount as the reference power for frequency support.

[0097] Example 3

[0098] This embodiment provides a control system for a wind power energy storage system, including a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, the steps of the method are implemented.

[0099] Example 4

[0100] This embodiment provides a computer-readable storage medium with a computer program stored thereon. When the computer program is executed by a processor, the steps of the method are implemented.

[0101] Those skilled in the art should understand that the embodiments of the present invention can be provided as a method, a system, or a computer program product. Therefore, the present invention can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present invention can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0102] It should be understood that the present invention can be implemented by computer program instructions for each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate means for implementing the specified functions in one process Figure 1 one process or multiple processes and / or blocks Figure 1 one block or multiple blocks.

[0103] Those skilled in the art can easily understand that the above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A coordinated frequency support control method for a wind power energy storage system, characterized in that: include: S1: When a sudden load event occurs in the wind power energy storage system, the wind farm group in the wind power energy storage system is started to perform coordinated frequency support control; S2: During the coordinated frequency support control of the wind farm group, if the torque of some wind turbines exceeds the limit, the coordinated frequency support control of the wind turbines is switched to the torque limit control; S3: Calculating the difference between the power reference value corresponding to the coordinated frequency support control of the wind farm group and the power reference value corresponding to the torque limit control of some wind turbines therein; S4: allocating the difference of the power reference value to each energy storage device in the wind power energy storage system, and controlling each energy storage device to use the allocated power quota as reference power for frequency support; After S4, the method further includes: When it is detected that the output power of the energy storage device reaches the maximum value and is maintained for a second preset time, after reaching the second preset time, the power recovery slope of each energy storage device is set according to the initial charge state. The output power in this stage is: P' ESS,j (t) = P ESS,j (t p )+k st ·k soc t; Among them, P' ESS,j (t) is the output power of the jth energy storage device at the current time t, P ESS,j (t p ) is the maximum output power of the jth energy storage device at time t p The corresponding output power, k st is the intrinsic recovery slope, k soc is the adaptive recovery slope, k soc It is proportional to the SOC of the energy storage device.

2. The coordinated frequency support control method of the wind power energy storage system according to claim 1, characterized in that: The S3 includes: Using the formula calculating a difference in the power reference value; Where m is the serial number of the fan with torque over-limit; k is the total number of fans with torque over-limit; n is the total number of fans; P sref,m (t) is the output power reference value of the mth wind turbine when performing coordinated frequency support control, P TLC,m (t) is the power reference value of the mth fan during torque limit control, P x,m (t) is the difference in power reference value corresponding to the mth wind turbine.

3. The coordinated frequency support control method of the wind power energy storage system according to claim 1, characterized in that: The S4 includes: S41: allocating the difference of the power reference value to the corresponding energy storage device in proportion according to the charge state of each energy storage device; S42: Control each of the energy storage devices to use the allocated power quota as reference power for frequency support.

4. The coordinated frequency support control method of the wind power energy storage system according to claim 3, characterized in that: The S41 includes: Using the formula Power quota is allocated to each of the energy storage devices; wherein, P ESS,j (t) is the output power reference value of the jth energy storage device when it performs frequency support, SOC 0,j is the initial charge state of the jth energy storage device; m is the serial number of the wind turbine with torque over-limit; k is the total number of wind turbines with torque over-limit, P x,m (t) is the difference in power reference value of the mth wind turbine.

5. The coordinated frequency support control method of the wind power energy storage system according to claim 1, characterized in that: The judgment condition for the fan torque exceeding the limit in S2 is: if the electromagnetic torque T e If the torque is greater than the torque threshold, the fan is considered to have exceeded the torque limit.

6. The coordinated frequency support control method for a wind power energy storage system according to any one of claims 1 to 5, characterized in that: After S4, the method further includes: When the grid frequency on the wind power group grid-connected bus reaches the lowest point, it is maintained for a first preset time; after the first preset time is reached, the wind turbine speed is restored according to a preset curve.

7. A coordinated frequency support control device for a wind power energy storage system, characterized in that: A coordinated frequency support control method for a wind power energy storage system for executing any one of claims 1 to 6, comprising: A starting module, used to start the wind farm group in the wind power energy storage system to perform coordinated frequency support control when a sudden load event occurs in the wind power energy storage system; A switching module is used to switch the wind turbines from the coordinated frequency support control to the limited torque control if the torque of some wind turbines exceeds the limit during the coordinated frequency support control of the wind farm group; A calculation module, used for calculating the difference between a power reference value corresponding to the coordinated frequency support control of the wind farm group and a power reference value corresponding to the torque limit control of some wind turbines therein; The support module is used to distribute the difference of the power reference value to each energy storage device in the wind power energy storage system, and control each energy storage device to use the distributed power quota as the reference power for frequency support.

8. A control system for a wind power storage system, comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 6 are implemented.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

Images