Charging and discharging control method and device of storage battery energy storage system, medium and product

Abstract

The invention discloses a charging and discharging control method and device for a storage battery energy storage system, a medium and a product, and relates to the technical field of storage batteries, and the method comprises the steps: determining the current state of the storage battery energy storage system based on the change of a DC bus voltage; dividing a plurality of charge state ranges; determining a charge state range corresponding to the charge state of the storage battery according to the charge state of the storage battery monitored in real time; and determining the current control mode of the storage battery based on the charge state range corresponding to the charge state of the storage battery, the current state and the maximum charge-discharge rate. By monitoring the charge state of the storage battery in real time, the control mode of the storage battery is controlled, the situation of overcharge or overdischarge of the storage battery is avoided, the performance of the storage battery energy storage system is improved, and the service life of the storage battery energy storage system is prolonged.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a charge and discharge control method, device, medium and product for a battery energy storage system. Background Art

[0002] As a key technology supporting the construction of new energy systems and new power systems, new energy storage has seen steady growth in application scenarios and construction scale. Among all new energy storage technologies, electrochemical energy storage accounts for nearly 96% of the installed capacity, with battery energy storage dominating the market.

[0003] Although batteries have many advantages such as high energy density, long cycle life, and fast charge and discharge, they are limited by the technical level and cannot flexibly and stably control the charge and discharge of batteries, resulting in overcharge or over-discharge of batteries. In the long run, this will inevitably lead to certain safety hazards in the battery energy storage system. As a core energy storage component, the safety and reliability of batteries determine the overall safety and economy of battery energy storage systems. Reasonable charge and discharge control methods for batteries are directly related to the performance, life, overall safety and reliability of battery energy storage systems, which is also a key factor affecting the comprehensive promotion of battery energy storage systems.

[0004] Therefore, there is an urgent need for a charge and discharge control method for a battery energy storage system to improve the safety and reliability of the battery energy storage system, thereby improving the performance and service life of the battery energy storage system. Summary of the invention

[0005] The purpose of this application is to provide a charge and discharge control method, device, medium and product for a battery energy storage system, which can solve the problem of low safety and reliability of the battery energy storage system caused by long-term overcharging or over-discharging of the battery in the prior art.

[0006] To achieve the above objectives, this application provides the following solutions:

[0007] In a first aspect, the present application provides a charge and discharge control method for a battery energy storage system, wherein the battery energy storage system includes a battery and an energy storage converter, wherein the energy storage converter is used to adjust the voltage and current of the battery; the safe charge and discharge control method for the battery energy storage system includes:

[0008] Based on the change of the DC bus voltage, the current state of the battery energy storage system is determined; the current state includes a charging state and a discharging state; the DC bus voltage represents a common voltage source; the battery energy storage system stabilizes the DC bus voltage by charging or discharging;

[0009] Divide into multiple state of charge ranges;

[0010] Determining a state of charge range corresponding to the state of charge of the battery according to the state of charge of the battery monitored in real time;

[0011] Based on the state of charge range corresponding to the state of charge of the battery, the current state and the maximum charge and discharge rate, the current control mode of the battery is determined; the control modes include: adaptive charge and discharge mode, constant current charging mode, constant current discharge mode, constant voltage charging mode and sleep mode; the maximum charge and discharge rate includes maximum charge rate and maximum discharge rate.

[0012] In a second aspect, the present application provides a computer device, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the charge and discharge control method for the battery energy storage system described above.

[0013] In a third aspect, the present application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the charge and discharge control method for the battery energy storage system described above.

[0014] In a fourth aspect, the present application provides a computer program product, including a computer program, which, when executed by a processor, implements any of the above-mentioned methods for controlling charging and discharging of a battery energy storage system.

[0015] According to the specific embodiments provided in this application, this application discloses the following technical effects:

[0016] The present application provides a charge and discharge control method, device, medium and product for a battery energy storage system. The present application first determines the current state of the battery energy storage system based on the change of the DC bus voltage, and then divides it into multiple charge state ranges, and determines the charge state range corresponding to the battery's charge state according to the real-time monitored battery's charge state. Furthermore, the current control mode of the battery is determined according to the charge state range corresponding to the battery's charge state, the current state and the maximum charge and discharge rate. That is, by finding the charge state range corresponding to the battery's charge state through the monitored battery's charge state, and combining the current state and the maximum charge and discharge rate, the current control mode of the battery can be flexibly and accurately determined to prevent the battery from being overcharged or over-discharged, thereby improving the safety and reliability of the battery energy storage system, and thereby improving the performance and service life of the battery energy storage system. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 A schematic diagram of a flow chart of a charge and discharge control method for a battery energy storage system provided in an embodiment of the present application;

[0019] Figure 2 A topological structure diagram of a battery energy storage system provided in an embodiment of the present application;

[0020] Figure 3 A schematic diagram of a safe charging and discharging control strategy for a battery energy storage system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0022] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0023] Example 1

[0024] like Figure 1 As shown, the present application provides a charge and discharge control method for a battery energy storage system, the battery energy storage system includes a battery and an energy storage converter, the energy storage converter is used to adjust the voltage and current of the battery, and the safe charge and discharge control method of the battery energy storage system includes:

[0025] Step 101: Based on the change of the DC bus voltage, determine the current state of the battery energy storage system; the current state includes a charging state and a discharging state; the DC bus voltage represents a common voltage source; the battery energy storage system stabilizes the DC bus voltage by charging or discharging.

[0026] The external working condition of the battery energy storage system is determined according to the change of the DC bus voltage, and whether the battery energy storage system is in a charging state or a discharging state is determined according to the external working condition.

[0027] Step 102: Divide into multiple state of charge ranges.

[0028] In some embodiments, step 102 specifically includes: dividing the state of charge into a first state of charge range, a second state of charge range, and a third state of charge range; wherein the first state of charge range is (15%, 95%); the second state of charge range is [0, 15%]; and the third state of charge range is [95%, 100%].

[0029] Step 103: According to the real-time monitored state of charge of the battery, a state of charge range corresponding to the state of charge of the battery is determined.

[0030] Specifically, the battery state of charge is based on

[0031] Wherein, SoC is the state of charge of the battery; SoC(0) is the initial charge state of the battery; i bat (τ) is the battery discharge current at the current moment; C bat is the nominal capacity of the battery; t is the time; τ is the current moment.

[0032] Step 104: Based on the state of charge range, determine the current control mode of the battery according to the state of charge of the battery, the current state and the maximum charge and discharge rate; the control modes include: adaptive charge and discharge mode, constant current charge mode, constant current discharge mode, constant voltage charge mode and sleep mode; the maximum charge and discharge rate includes maximum charge rate and maximum discharge rate.

[0033] In some embodiments, step 104 specifically includes:

[0034] Step 201: When the state of charge range corresponding to the state of charge of the battery is a first state of charge range and the current state is a charging state, based on the maximum charge and discharge rate, determine that the current control mode is an adaptive charge and discharge mode or a constant current charging mode; wherein the constant current charging mode charges the battery energy storage system with a constant charging current; and the constant charging current is determined according to the maximum charging rate.

[0035] In some embodiments, step 201 specifically includes: when the charging current of the battery is greater than or equal to the current corresponding to the maximum charging rate, determining that the current control mode is the constant current charging mode; when the charging current of the battery is less than the current corresponding to the maximum charging rate, determining that the current control mode is the adaptive charging and discharging mode.

[0036] Step 202: When the state of charge range corresponding to the state of charge of the battery is a first state of charge range and the current state is a discharge state, based on the discharge current of the battery and the maximum discharge rate, determine that the current control mode is the constant current discharge mode; wherein the constant current discharge mode discharges the battery energy storage system with a constant discharge current; and the constant discharge current is determined according to the maximum discharge rate.

[0037] Step 203: When the state of charge range corresponding to the state of charge of the battery is the second state of charge range and the current state is the charging state, based on the charging current of the battery and the maximum charging rate, determine that the current control mode is the adaptive charge and discharge mode or the constant current charging mode; wherein the constant current charging mode charges the battery energy storage system with a constant charging current; and the constant charging current is determined according to the maximum charging rate.

[0038] In some embodiments, step 203 specifically includes: when the charging current of the battery is less than the current corresponding to the maximum charging rate, determining that the current control mode is the adaptive charging and discharging mode; when the charging current of the battery is greater than or equal to the current corresponding to the maximum charging rate, determining that the current control mode is the constant current charging mode.

[0039] Step 204: When the state of charge range corresponding to the state of charge of the battery is a second state of charge range and the current state is a discharge state, determine that the current control mode is the sleep mode; wherein the sleep mode indicates that the battery energy storage system is disconnected from the DC bus voltage.

[0040] Step 205: When the state of charge range corresponding to the state of charge of the battery is a third state of charge range and the current state is a charging state, determine that the current control mode is the constant voltage charging mode; wherein the constant voltage charging mode charges the battery energy storage system with a preset constant safety voltage.

[0041] Step 206: When the state of charge range corresponding to the state of charge of the battery is the third state of charge range and the current state is the discharge state, based on the discharge current of the battery and the maximum discharge rate, determine that the current control mode is the adaptive charge and discharge mode or the constant current discharge mode.

[0042] In some embodiments, step 206 specifically includes:

[0043] When the discharge current of the battery is less than the current corresponding to the maximum discharge rate, determining that the current control mode is the adaptive charge and discharge mode;

[0044] When the discharge current of the storage battery is greater than or equal to the current corresponding to the maximum discharge rate, the current control mode is determined to be the constant current discharge mode.

[0045] like Figure 2 As shown in the figure, the battery and the energy storage converter constitute a battery system. The energy storage converter can adjust the input and output voltage and current of the battery. bus Represents the DC bus capacitance; V bus Indicates the actual DC bus voltage; V bat Indicates the battery voltage; i bat Indicates the battery discharge current; C bat Indicates the nominal capacity of the battery; the energy storage converter is the matching DC / DC power converter. The topology of the battery energy storage system is not restricted here, and the battery charging and discharging control is controlled by Figure 2 accomplish.

[0046] Among them, the application scenarios of the battery system are mostly to connect the DC bus with other power sources (such as new energy) and DC loads to form a system similar to a DC microgrid. Whether the power in the system is balanced is directly reflected in the fluctuation of the DC bus. Usually, the DC bus voltage is stable within a fixed range. When the DC bus voltage increases, it means that the output power of the power source is greater than the power consumed by the load. At this time, the power output of the power source should be limited to maintain the stability of the DC bus voltage; when the DC bus voltage decreases, it means that the output power of the power source is less than the power consumed by the load. At this time, the power output of the power source should be increased. The battery system can be used as a power source or as a load. The DC bus voltage can be maintained constant by adjusting the operating state of the battery system, that is, the stability of the entire system.

[0047] Example 2

[0048] Reference Figure 3 , numbers 1-5 correspond to the five control modes of the battery. According to the different state of charge (SoC) of the battery, its charge and discharge control strategy can be divided into the following five different modes, including:

[0049] 1) Adaptive charge and discharge mode (mode 1): The battery system dynamically adjusts the operating state according to the DC bus voltage state. In order to avoid overcharge and overdischarge of the battery, the maximum charge rate is limited to 0.5C and the maximum discharge rate is limited to -0.5C. At the same time, the battery SoC is monitored in real time. When the battery is in a charging state and the SoC exceeds 95%, the battery is switched to a constant voltage charging mode; when the battery is in a discharging state and the SoC is less than 15%, the battery is switched to a sleep mode.

[0050] 2) Constant current charging mode (mode 2): The battery is charged with a constant charging current. To avoid overcharging of the battery, when the SoC of the battery reaches 95%, the battery is switched to constant voltage charging.

[0051] 3) Constant current discharge mode (mode 3): The battery is discharged at a constant discharge current. To avoid over-discharge of the battery, when the SoC of the battery is lower than 15%, the battery is switched to sleep mode.

[0052] 4) Constant voltage charging mode (mode 4): When the battery SoC exceeds 95%, it is close to a fully charged state. In order to avoid overcharging or self-consumption of the battery, the battery is charged at a preset battery safety charging voltage.

[0053] 5) Sleep mode (mode 5): The SoC of the battery is lower than the discharge depth threshold of 15%. In order to avoid over-discharge of the battery, when the battery is in a discharge state and the SoC is lower than 15%, the battery system is disconnected from the DC bus.

[0054] In practical applications, the operating conditions include charging in full charge state, discharging in full charge state, charging in normal state, discharging in normal state, charging in low charge state, discharging in low charge state, and disconnection. Among them, the full charge state is the third state of charge range [95%, 100%], the normal state is the first state of charge range (15%, 95%), and the low charge state is the second state of charge range [0, 15%].

[0055] Among them, charging in fully charged state: the charging rate is limited to a fixed voltage by monitoring the battery voltage; discharging in fully charged state: the discharge rate is limited to a maximum of -0.5C by monitoring the battery discharge current; charging in normal state: the charging rate is limited to a maximum of 0.5C by monitoring the battery charging current; discharging in normal state: the discharge rate is limited to a maximum of -0.5C by monitoring the battery discharge current; charging in low-power state: the charging rate is limited to a maximum of 0.5C by monitoring the battery current.

[0056] Where C represents the battery charge and discharge rate. The charge rate is the ratio of the charge current to the nominal capacity, and the discharge rate is the ratio of the discharge current to the nominal capacity. Because the nominal capacity of the battery is different, the current corresponding to 0.5C is different. For example: a battery with a nominal capacity of 100Ah is discharged with a discharge current of 50A, and the discharge rate is 50 / 100=0.5C. It is discharged with a discharge current of 100A, and the discharge rate is 100 / 100=1C.

[0057] like Figure 3As shown, the current control mode of the battery is the adaptive charge and discharge mode. When the battery needs to switch to mode 2, the mode switch will switch to mode 2, and the control loop will change accordingly. When the current control mode of the battery is mode 5, the drive signal of the energy storage inverter is locked to 0, that is, the energy storage inverter stops working and disconnects the battery system from the DC bus. The mode switch is not a physical switch.

[0058] In the present application, the control mode of the battery is equivalent to a mode switching switch, and the control mode of the battery is automatically switched according to the detected SoC of the battery.

[0059] like Figure 3 As shown, V bat Indicates the battery voltage; V bus is the actual DC bus voltage; is the reference value of the DC bus voltage, V safe is the preset battery safety charging voltage; PI is a PI controller, which automatically generates a pulse trigger signal for the energy storage converter to complete the control of the energy storage converter. The PI controller is used to adjust the DC bus voltage. The limiter is used to limit the output current of the PI controller, and the limiter limits the current reference value between (-0.5C) and (0.5C). PWM converts the output signal of the PI controller into a pulse width modulation (PWM) signal for controlling the energy storage converter. Among them, mode 1 and mode 4 have two PI controllers (i.e., the outer loop PI controller and the inner loop PI controller), and mode 2 and mode 3 only use the inner loop PI controller. The outer loop PI controller is used to generate the inductor current reference value, and the deviation between the inductor current reference value and the actual value of the inductor current is used as the input of the inner loop PI controller. The inner loop PI controller is used to generate the duty cycle of the control signal of the switch device of the energy storage converter (the duty cycle generates a trigger signal through the PWM module). Figure 3 This is an existing double closed-loop control structure and will not be described in detail here.

[0060] According to the SoC of the battery and the operating conditions of the battery energy storage system, the control mode can be automatically switched, and the charging and discharging rate of the battery can be adjusted by switching between different control modes through the set maximum charging and discharging rate to prevent the battery from being overcharged and over-discharged. In addition, different control modes of the battery can be switched seamlessly without affecting the stable operation of the battery energy storage system.

[0061] In an exemplary embodiment, a computer device is further provided, including a memory and a processor, wherein a computer program is stored in the memory, and the above method is implemented when the processor executes the computer program.

[0062] In an exemplary embodiment, a computer-readable storage medium is provided, storing a computer program, and the computer program implements the above method when executed by a processor.

[0063] In an exemplary embodiment, a computer program product is provided, including a computer program, which implements the above method when executed by a processor.

[0064] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with relevant regulations.

[0065] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiments can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRdM), magnetic random access memory (MRdM), ferroelectric random access memory (FRdM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RdM) or external cache memory, etc. By way of illustration and not limitation, RdM may be in various forms, such as static random access memory (SRdM) or dynamic random access memory (DRdM).

[0066] The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. The non-relational database may include a distributed database based on blockchain, etc., but is not limited thereto. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but is not limited thereto.

[0067] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0068] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A charge and discharge control method for a battery energy storage system, characterized in that: The battery energy storage system includes a battery and an energy storage converter, wherein the energy storage converter is used to adjust the voltage and current of the battery; the safe charging and discharging control method of the battery energy storage system includes: Based on the change of the DC bus voltage, the current state of the battery energy storage system is determined; the current state includes a charging state and a discharging state; the DC bus voltage represents a common voltage source; the battery energy storage system stabilizes the DC bus voltage by charging or discharging; Divide into multiple state of charge ranges; Determining a state of charge range corresponding to the state of charge of the battery according to the state of charge of the battery monitored in real time; Based on the state of charge range corresponding to the state of charge of the battery, the current state and the maximum charge and discharge rate, the current control mode of the battery is determined; the control modes include: adaptive charge and discharge mode, constant current charging mode, constant current discharge mode, constant voltage charging mode and sleep mode; the maximum charge and discharge rate includes maximum charge rate and maximum discharge rate.

2. The charge and discharge control method of the battery energy storage system according to claim 1, characterized in that: Divide into multiple state of charge ranges, including: The state of charge is divided into a first state of charge range, a second state of charge range and a third state of charge range; wherein the first state of charge range is (15%, 95%); the second state of charge range is [0, 15%]; and the third state of charge range is [95%, 100%].

3. The charge and discharge control method of the battery energy storage system according to claim 2, characterized in that: Determining a current control mode of the battery based on the state of charge range, the current state, and the maximum charge and discharge rate specifically includes: When the state of charge range corresponding to the state of charge of the battery is the first state of charge range and the current state is the charging state, based on the maximum charge and discharge rate, determining that the current control mode is an adaptive charge and discharge mode or a constant current charging mode; wherein the constant current charging mode charges the battery energy storage system with a constant charging current; and the constant charging current is determined according to the maximum charging rate; When the state of charge range corresponding to the state of charge of the battery is the first state of charge range and the current state is the discharge state, based on the discharge current of the battery and the maximum discharge rate, the current control mode is determined to be the constant current discharge mode; wherein the constant current discharge mode discharges the battery energy storage system with a constant discharge current; and the constant discharge current is determined according to the maximum discharge rate; When the state of charge range corresponding to the state of charge of the battery is the second state of charge range and the current state is the charging state, based on the charging current of the battery and the maximum charging rate, determining that the current control mode is the adaptive charging and discharging mode or the constant current charging mode; wherein the constant current charging mode charges the battery energy storage system with a constant charging current; and the constant charging current is determined according to the maximum charging rate; When the state of charge range corresponding to the state of charge of the battery is the second state of charge range and the current state is the discharge state, determining that the current control mode is the sleep mode; wherein the sleep mode indicates that the battery energy storage system is disconnected from the DC bus voltage; When the state of charge range corresponding to the state of charge of the battery is a third state of charge range and the current state is a charging state, determining that the current control mode is the constant voltage charging mode; wherein the constant voltage charging mode charges the battery energy storage system at a preset battery safety charging voltage; When the state of charge range corresponding to the state of charge of the battery is a third state of charge range and the current state is a discharge state, based on the discharge current of the battery and the maximum discharge rate, the current control mode is determined to be the adaptive charge and discharge mode or the constant current discharge mode.

4. The charge and discharge control method of the battery energy storage system according to claim 3, characterized in that: When the state of charge range corresponding to the state of charge of the battery is a first state of charge range and the current state is a charging state, determining the current control mode to be an adaptive charge and discharge mode or a constant current charging mode based on the maximum charge and discharge rate specifically includes: When the charging current of the battery is greater than or equal to the current corresponding to the maximum charging rate, determining that the current control mode is the constant current charging mode; When the charging current of the battery is less than the current corresponding to the maximum charging rate, the current control mode is determined to be the adaptive charging and discharging mode.

5. The charge and discharge control method of the battery energy storage system according to claim 3, characterized in that: When the state of charge range corresponding to the state of charge of the battery is the second state of charge range and the current state is the charging state, determining the current control mode to be the adaptive charge and discharge mode or the constant current charging mode based on the charging current of the battery and the maximum charging rate specifically includes: When the charging current of the battery is less than the current corresponding to the maximum charging rate, determining that the current control mode is the adaptive charging and discharging mode; When the charging current of the battery is greater than or equal to the current corresponding to the maximum charging rate, the current control mode is determined to be the constant current charging mode.

6. The charge and discharge control method of the battery energy storage system according to claim 3, characterized in that: When the state of charge range corresponding to the state of charge of the battery is a third state of charge range and the current state is a discharge state, determining the current control mode to be the adaptive charge and discharge mode or the constant current discharge mode based on the discharge current of the battery and the maximum discharge rate specifically includes: When the discharge current of the battery is less than the current corresponding to the maximum discharge rate, determining that the current control mode is the adaptive charge and discharge mode; When the discharge current of the storage battery is greater than or equal to the current corresponding to the maximum discharge rate, the current control mode is determined to be the constant current discharge mode.

7. The charge and discharge control method of the battery energy storage system according to claim 1, characterized in that: according to Determine the state of charge of the battery; wherein SoC is the state of charge of the battery; SoC(0) is the initial charge state of the battery; i bat (τ) is the battery discharge current at the current time τ; C bat is the nominal capacity of the battery; t is the time; τ is the current moment.

8. A computer device comprising: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the charge and discharge control method for the battery energy storage system according to any one of claims 1 to 7.

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 charge and discharge control method of the battery energy storage system described in any one of claims 1 to 7 is implemented.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the charge and discharge control method of the battery energy storage system described in any one of claims 1 to 7 is implemented.

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