Charging method and charging device based on full matrix coding mechanism

Abstract

The present invention discloses a charging method and a charging device based on a full matrix coding mechanism. In the full matrix coding mechanism, the charging gun number is the longitude, the power module group number is the latitude, and the intersection is the switch group number of the circuit switching switch group between the corresponding charging gun and the power module group. The charging gun number and the power module group number are both n, n is a natural number starting from 1, and the switch group number of the circuit switching switch group is coded and distinguished by the longitude and latitude coordinates (n, n); the steps of the method include a charging circuit switching process, and the charging circuit switching process includes starting the charging process, and the starting charging process is: charging gun n starts charging, specifying power module group n, and then specifying the circuit switching switch group and closing its corresponding circuit switching switch group (n, n). The present invention uses the full matrix coding relationship to quickly, conveniently and easily find the corresponding charging circuit, improve the charging efficiency, and ensure that the entire charging circuit is simple and safe.

Description

Technical Field

[0001] The invention relates to a charging method and a charging device based on a full-matrix coding mechanism, belonging to the technical field of electric vehicle charging. Background Art

[0002] At present, with the popularization of new energy electric vehicle charging technology, new energy electric vehicles have an increasing demand for charging equipment, especially the demand for the power available for charging equipment. DC high-power charging can provide higher charging power and faster charging speed, thereby greatly shortening the charging time and effectively improving the user's usage efficiency and charging experience. During high-power charging, as the battery capacity saturation changes, the power demand becomes smaller and smaller. The dynamic switching of large and small powers can better control the battery charging current and voltage, which can effectively reduce battery loss, improve duration and charging efficiency, and improve battery reliability and stability.

[0003] High-power single-gun DC charging equipment can meet the needs of dynamic switching between large and small powers. However, as the charging power demand decreases, the idle rate of the DC power module also increases accordingly, resulting in a huge waste of resources. High-power multi-gun DC charging equipment can not only meet the switching of large and small powers, but also use the idle power modules on other charging guns, making full use of resources better and faster. Multi-gun DC charging equipment can provide charging ports for multiple electric vehicles at the same time, can provide simultaneous charging services for multiple electric vehicles, and provide power for multiple electric vehicles, avoiding the unnecessary space consumption of setting up a charging pile for each electric vehicle, greatly improving charging efficiency and shortening charging time, which is very meaningful for charging services in areas with dense electric vehicles.

[0004] In high-power multi-gun DC charging equipment, the DC power module group and the charging gun are controlled by a relay switch group to select the separation and combination of the charging circuit. The DC power module group is composed of one or more 20kW, 30kW, 40kW and other commonly used power modules, and the relay switch group is composed of an L-line switch and an N-line switch. The charging circuit switching algorithm is one of the key technologies of multi-gun charging equipment. It provides electric vehicles with a variety of charging methods and multiple power sources. It can make full use of local power sources to maximize energy utilization, and it is also conducive to reducing energy loss and reducing the impact on the energy environment. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a charging method for a charging device based on a full matrix coding mechanism, which utilizes the full matrix coding relationship to quickly, conveniently and easily find the corresponding charging circuit, improve the charging efficiency, and ensure that the entire charging circuit is switched simply and safely.

[0006] In order to solve the above technical problems, the technical solution of the present invention is: a charging method for a charging device based on a full matrix coding mechanism, in which the charging gun number is the longitude, the power module group number is the latitude, the intersection is the switch group number of the circuit switching switch group between the corresponding charging gun and the power module group, the charging gun number and the power module group number are both n, n is a natural number starting from 1, and the switch group number of the circuit switching switch group is coded and distinguished by the longitude and latitude coordinates (n, n); the steps of the method include a charging circuit switching process, and the charging circuit switching process includes starting the charging process, and the starting charging process is:

[0007] Charging gun n starts charging, specifies power module group n, then specifies the circuit switching switch group and closes its corresponding circuit switching switch group (n, n), locks the charging circuit composed of the corresponding charging gun, the specified power module group and the specified corresponding circuit switching switch group for charging; wherein, charging gun n is the charging gun with charging gun number n, power module group n is the power module group with power module group number n, and circuit switching switch group (n, n) is the circuit switching switch group with switch group number (n, n).

[0008] Further, the charging process is as follows:

[0009] S11: Charging gun n starts charging. When the corresponding charging gun is connected to the electric authorization, charging starts, and the charging circuit locking process is started to enter step S12;

[0010] S12: Specifying a dedicated power module group n: Specifying a dedicated power module group number n according to the charging gun number n, and proceeding to step S13;

[0011] S13: Determine whether the power module group n is working: if it is working, go to step S14, otherwise go to step S15;

[0012] S14: All loop switch groups in the n-dimensional power module group are operated separately, and the process goes to step S15;

[0013] S15: The circuit switch group of the power module group n and the charging gun n that intersects the longitude and latitude is combined and operated, and the process proceeds to step S16;

[0014] S16: Lock the power module group n and the charging gun n charging circuit start module for charging.

[0015] Furthermore, the charging gun number, the power module group number and the corresponding switch group number have the following corresponding relationship: switch group number = (power module group number-1)×number of charging guns+charging gun number; wherein the number of charging guns is the number of charging guns of the charging device.

[0016] Furthermore, in order to adapt to the application requirements of large and small power scenarios, the charging circuit switching process also includes charging gun n demand detection and charging circuit increase and decrease process: that is, when the power demand of charging gun n changes in step size and the absolute value of the change is greater than the power of the power module group, the charging circuit between the idle and low-frequency power module group and the charging gun n is increased in turn according to the positive and negative changes, that is, the corresponding circuit switching switch group is closed or the charging circuit between the high-frequency power module group and the charging gun n other than the exclusive power module group n is reduced in turn, that is, the corresponding circuit switching switch group is divided.

[0017] Furthermore, the charging gun n needs to be detected, and the charging circuit increase and decrease process is as follows:

[0018] S21: Charging gun n demand detection: Charging gun n demand change detection, increase or decrease the charging circuit according to the change amount, and enter step S22;

[0019] S22: specifying the power difference between the required charging power and the actual output power;

[0020] S23: Determine whether the absolute value of the power difference is greater than the power of the power module group. If the absolute value of the power difference is less than the power, the existing charging circuit is maintained and the process ends. If the absolute value of the power difference is greater than the power, the process proceeds to step S24.

[0021] S24: Determine whether the power difference is a positive number, if it is a positive number, proceed to step S25, if it is a negative number, proceed to step S26;

[0022] S25: Add charging circuit: If there is no idle power module group, no charging circuit is added to maintain the status quo and charge balance to end this process; if there is an idle power module group, select the charging circuit composed of the idle power module group with the lowest usage frequency and charging gun n, close all switches under the corresponding circuit switching switch group to add a charging circuit to start the power module group to supplement the charging power and improve the charging efficiency;

[0023] S26: Reduce the charging circuit: Select the most frequently used power module group except the dedicated power module group and the charging gun n to form a charging circuit, and operate all switches under the corresponding circuit switching switch group to reduce the charging circuit, turn off the power module group, adjust the charging power, and provide it for other charging guns to use to improve the charging efficiency.

[0024] Furthermore, the charging circuit switching process also includes a charging gun n finishing charging and a charging circuit releasing process, that is, when the charging gun n finishes charging, all circuit switching switch groups in the charging gun number dimension are disconnected to release the charging circuit for the next charging.

[0025] Furthermore, when charging gun n ends charging, the charging circuit release process is as follows:

[0026] S31: Charging gun n ends charging: When charging gun n stops charging, the charging circuit release process starts and enters step S32;

[0027] S32: The circuit switching switch group of the charging gun n that intersects the longitude and latitude is operated separately. The circuit switching switch group of the charging gun n that intersects the longitude and latitude is the circuit switching switch group on all power module groups and the charging circuit of the charging gun n. All switches in the circuit switching switch group are disconnected to restore the charging circuits of all charging guns n to prepare for the next charging, and then enter step S33;

[0028] S33: The charging circuit stop module is restored to stop charging.

[0029] Furthermore, the method also includes the following steps: performing a safety detection process while switching the charging circuit, the safety detection process including: charging gun safety detection and / or power module group safety detection and / or circuit switching switch group safety detection.

[0030] If an abnormal state occurs during the safety detection process, the corresponding charging circuit will be disconnected immediately to ensure charging safety;

[0031] And / or in the charging gun safety test, detect the charging gun over-temperature, over-voltage, over-current, insulation, BMS, and communication abnormality;

[0032] And / or in the power module group safety detection, detect the over-temperature, communication, and out-of-control abnormal states of all modules in the power module group;

[0033] And / or in the safety detection of the circuit switching switch group, detect the abnormal states of adhesion, malfunction and refusal to operate of all switches in the circuit switching switch group.

[0034] The present invention also provides a charging device for implementing the above charging method.

[0035] After adopting the above technical solution, the coding mechanism of the full matrix relationship between the charging gun, the power module group and the circuit switching switch group meets all common and uncommon multi-gun DC charging devices. The coding relationship is used to quickly and easily find the corresponding charging circuit to improve the charging efficiency and ensure that the entire charging circuit is simple and safe. At the same time, the charging circuit is dynamically switched according to the number of charging guns and the charging requirements of the charging guns during the switching process, which improves the charging efficiency of the charging equipment, shortens the charging cycle, and enhances the user experience. During the charging circuit switching process, the circuit is also balanced according to the frequency of use of the power module group to increase the module life and reduce the module failure rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a full matrix relationship diagram of the power module group, charging gun and loop switching switch group of the present invention;

[0037] Figure 2 A flow chart of a charging circuit switching process in the method of the present invention;

[0038] Figure 3 It is a safety detection flow chart in the method of the present invention;

[0039] Figure 4 This is a flow chart of the process of starting charging in the method of the present invention;

[0040] Figure 5 It is a flow chart of the charging circuit increase and decrease process in the method of the present invention;

[0041] Figure 6 The figure is a flow chart of the charging circuit release process in the method of the present invention. DETAILED DESCRIPTION

[0042] In order to make the contents of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments in conjunction with the accompanying drawings.

[0043] Common multi-gun DC charging equipment includes 80kW / 120kW / 160 dual-gun DC charging pile, 240kW / 320kW four-gun DC charging pile, 360kW / 480kW six-gun DC charging pile, 240kW / 320kW / 480Kw / 640kW eight-gun DC charging pile, 300kW / 600kW ten-gun DC charging pile, 360Kw / 480kW twelve-gun DC charging pile, etc. Charging equipment with more than four guns is also called charging pile. Common multi-gun DC charging equipment, the corresponding relationship between the total installed power, the number of charging guns, the number of power module groups, the power of a single module, the number of modules, the number of switch groups and the number of switches is shown in Table 1. The number of module groups is equal to the number of charging guns, the power of the module group is equal to the total installed power ÷ the number of charging module groups, and the power of the module group is also equal to an integer multiple of 20kW / 30kW / 40kW (from which we can know the common power selected for a single module), the number of modules is equal to the total installed power ÷ the power of a single module, the number of switch groups is equal to the number of charging guns × the number of module groups, and the number of switches is equal to the number of switch groups × 2. This relationship between the total installed power, the number of charging guns, the number of power module groups, the power of a single module, the number of modules, the number of switch groups and the number of switches is also applicable to uncommon types of multi-gun DC charging equipment, such as one gun, three guns, five guns, seven guns, nine guns, eleven guns, etc. Each charging gun in a multi-gun DC charging device has a dedicated power module group. When the charging gun starts charging, regardless of whether the dedicated power module group is idle, it must be allocated to this charging gun for charging, ensuring that the charging gun is charged with the minimum unit power (module group power). The dedicated power module group number is equal to the charging gun number. Figure 1 The circuit switching switch group on the middle diagonal line is the exclusive power module group and charging gun circuit switching switch group.

[0044] From Table 1, we can see that the only constant relationship is: the number of charging guns = the number of module groups, the number of switch groups = the number of charging guns × the number of module groups. The charging gun number is the longitude (1, 2, 3, ..., n), and the power module group number is the latitude (1, 2, 3, ..., n) to form a dot matrix coordinate diagram, where the intersection is the circuit switching switch group, and the number of intersections is the number of switch group points. Figure 1 As shown, each intersection, i.e., the switch group number, can be coded and distinguished using (module group number, charging gun number) as the longitude and latitude coordinates, and the charging gun number, module group number, and switch group number are defined as a full matrix relationship. Figure 1 Convention: The switch group has two states: open and closed. The open state means that the circuit switching switch group between the power module group and the charging gun is disconnected, and the closed state means that the circuit switching switch group between the power module group and the charging gun is closed. The circuit switching switch groups on the same longitude cannot be closed at the same time, that is, the same power module group cannot supply power to multiple charging guns. The circuit switching switch groups on the same latitude can be closed at the same time, that is, multiple power module groups can supply power to the same charging gun.

[0045] according to Figure 1 The power module group number, charging gun number and switch group number are coded as shown in Table 2, and the following can be obtained:

[0046] Switch group number = (power module group number - 1) × number of charging guns + charging gun number (Formula ①)

[0047] Formula description: In formula ①, the switch group number, module group number, number of charging guns and charging gun number are all greater than or equal to 1. When the multi-gun DC charging equipment is finalized, the number of charging guns, the number of switch groups and the number of module groups remain unchanged, the module group number is less than or equal to the number of module groups, the charging gun number is less than or equal to the number of charging guns, and the switch group number is less than or equal to the number of switch groups; Formula ① represents that the switch group number to be switched is equal to the difference between the module group number minus 1 multiplied by the number of charging guns plus the charging gun number.

[0048] Table 1. Corresponding quantity of charging guns, power modules and circuit switching switches for common charging equipment

[0049] Total installed power Number of charging guns Number of module groups Single module power Number of modules Number of switch groups Number of switches 80kW 2 2 20kW / 40kW 4 / 2 4 8 120 kW 2 2 20kW / 30kW 6 / 4 4 8 160kW 2 2 20kW / 40kW 8 / 4 4 8 240kW 4 4 20kW / 30kW 12 / 8 16 32 320kW 4 4 20kW / 40kW 16 / 8 16 32 360kW 6 6 20kW / 30kW 18 / 12 32 64 480kW 6 6 20kW / 40kW 24 / 12 32 64 240kW 8 8 30kW 8 64 128 320kW 8 8 40kW 8 64 128 480kW 8 8 30kW 16 64 128 640kW 8 8 40kW 16 64 128 300kW 10 10 30kW 10 100 200 400kW 10 10 40kW 10 100 200 600kW 10 10 30kW 20 100 200 360Kw 12 12 30kW 12 144 288 480kW 12 12 40kW 12 144 288

[0050] Table 2 Full matrix coding table of power module group, charging cable and circuit switch group

[0051] Switch group number Power module group number (latitude) Charging gun number (longitude) 1 1 1 2 1 2 3 1 3 …… …… …… n 1 n n+1 2 1 n+2 2 2 n+3 2 3 …… …… …… 2n 2 n 2n+1 3 1 2n+2 3 2 2n+3 3 3 …… …… …… 3n 3 n …… …… …… (n-1)*n+1 n 1 (n-1)*n+2 n 2 (n-1)*n+3 n 3 … … … n*n n n

[0052] like Figures 1 to 6As shown, a charging method for a charging device based on a full matrix coding mechanism, in which the charging gun number is the longitude, the power module group number is the latitude, the intersection is the switch group number of the circuit switching switch group between the corresponding charging gun and the power module group, the charging gun number and the power module group number are both n, n is a natural number starting from 1, and the switch group number of the circuit switching switch group is coded and distinguished by the longitude and latitude coordinates (n, n); the steps of the method include a charging circuit switching process, and the charging circuit switching process includes a charging start process, and the charging start process is:

[0053] Charging gun n starts charging, specifies power module group n, then specifies the circuit switching switch group and closes its corresponding circuit switching switch group (n, n), locks the charging circuit composed of the corresponding charging gun, the specified power module group and the specified corresponding circuit switching switch group for charging; wherein, charging gun n is the charging gun with charging gun number n, power module group n is the power module group with power module group number n, and circuit switching switch group (n, n) is the circuit switching switch group with switch group number (n, n).

[0054] Further, if Figure 4 As shown in the figure, the charging process is as follows:

[0055] S11: Charging gun n starts charging. When the corresponding charging gun is connected to the electric authorization, charging starts, and the charging circuit locking process is started to enter step S12;

[0056] S12: Specifying a dedicated power module group n: Specifying a dedicated power module group number n according to the charging gun number n, and proceeding to step S13;

[0057] S13: Determine whether the power module group n is working: if it is working, go to step S14, otherwise go to step S15;

[0058] S14: All circuit switch groups on the power module group n dimension are operated separately. To ensure charging safety, a power module group can only charge one charging gun at the same time. At the same time, the power module group is ready to stop working and switch to charging gun n. Figure 1 All switches on the power module are operated separately to ensure that the charging circuit of the dedicated power module is restored and ready for charging by the charging gun n, and then the process goes to step S15;

[0059] S15: The circuit switching switch group of the power module group n and the charging gun n that intersects the longitude and latitude is operated together. The switching circuit switching switch group of the power module group n and the charging gun n that intersects the longitude and latitude is the exclusive circuit switching switch group (n, n) of the power module group n and the charging gun n. Figure 1 As shown, close it and enter step S16;

[0060] S16: Lock the power module group n and the charging gun n charging circuit start module for charging.

[0061] Furthermore, the charging gun number, the power module group number and the corresponding switch group number have the following corresponding relationship (Formula ①): switch group number = (power module group number-1)×number of charging guns + charging gun number; wherein the number of charging guns is the number of charging guns of the charging device.

[0062] Furthermore, in order to adapt to the application requirements of large and small power scenarios, the charging circuit switching process also includes charging gun n demand detection and charging circuit increase and decrease process: that is, when the power demand of charging gun n changes in step size and the absolute value of the change is greater than the power of the power module group, the charging circuit between the idle and low-frequency power module group and the charging gun n is increased in turn according to the positive and negative changes, that is, the corresponding circuit switching switch group is closed or the charging circuit between the high-frequency power module group and the charging gun n other than the exclusive power module group n is reduced in turn, that is, the corresponding circuit switching switch group is divided.

[0063] Furthermore, the charging gun n needs to be detected, and the charging circuit increase and decrease process is as follows:

[0064] S21: Charging gun n demand detection: Charging gun n demand change detection, increase or decrease the charging circuit according to the change amount, and enter step S22;

[0065] S22: specifying the power difference between the required charging power and the actual output power; the charging device uses the available power module group to charge the electric vehicle according to the charging demand of the charging gun n. The actual output power is greater or less than the required charging power due to insufficient or surplus power module groups. The power difference between the required power and the actual output power is then dynamically adjusted according to the power difference;

[0066] S23: Determine whether the absolute value of the power difference is greater than the power of the power module group. If the absolute value of the power difference is less than the power, the existing charging circuit is maintained and the process ends. If the absolute value of the power difference is greater than the power, the process proceeds to step S24.

[0067] S24: Determine whether the power difference is a positive number: If it is a positive number, it means that the charging demand is much greater than the actual output power, that is, the current power module group is under-supplied, and it is necessary to increase the charging circuit to ensure full-load charging, then go to step S25; if it is a negative number, it means that the charging demand is much less than the actual output power, that is, the current power module group is over-supplied, and it is necessary to reduce the charging circuit to restore the circuit to other charging guns, then go to step S26;

[0068] S25: Add charging circuit: If there is no idle power module group, no charging circuit is added to maintain the status quo and charge balance to end this process; if there is an idle power module group, select the charging circuit composed of the idle power module group with the lowest usage frequency and charging gun n, and obtain the switch group number according to formula ①, knowing the charging gun number, the number of charging guns and the power module group number, and close all switches under the corresponding circuit switching switch group to increase the charging circuit and start the power module group to supplement the charging power and improve the charging efficiency;

[0069] S26: Reduce charging circuits: Select the most frequently used power module group except the dedicated power module group and the charging gun n to form a charging circuit. According to formula ①, the charging gun number, the number of charging guns and the power module group number are known to obtain the switch group number. All switches under the corresponding circuit switching switch group are operated separately to reduce the charging circuit, turn off the power module group, adjust the charging power, and provide it for other charging guns to use to improve charging efficiency.

[0070] Furthermore, the charging circuit switching process also includes a charging gun n finishing charging and a charging circuit releasing process, that is, when the charging gun n finishes charging, all circuit switching switch groups in the charging gun number dimension are disconnected to release the charging circuit for the next charging.

[0071] Furthermore, when charging gun n ends charging, the charging circuit release process is as follows:

[0072] S31: Charging gun n ends charging: When charging gun n is fully charged, abnormal fault occurs, etc., charging is stopped and the charging circuit is released, and the process enters step S32;

[0073] S32: The circuit switching switch group of the charging gun n that intersects the longitude and latitude is operated separately. The circuit switching switch group of the charging gun n that intersects the longitude and latitude is the circuit switching switch group on all power module groups and the charging circuit of the charging gun n. All switches in the circuit switching switch group are disconnected to restore the charging circuits of all charging guns n to prepare for the next charging, and then enter step S33;

[0074] S33: The charging circuit stop module is restored to stop charging.

[0075] Furthermore, the method also includes the following steps: performing a safety detection process while switching the charging circuit, the safety detection process including: charging gun safety detection, power module group safety detection, and circuit switching switch group safety detection.

[0076] If an abnormal state occurs during the safety detection process, the corresponding charging circuit will be disconnected immediately to ensure charging safety;

[0077] In the charging gun safety test, detect the charging gun over-temperature, over-voltage, over-current, insulation, BMS, and communication abnormalities;

[0078] In the power module group safety detection, all modules in the power module group are detected for over-temperature, communication, and out-of-control abnormal conditions;

[0079] In the safety inspection of the circuit switching switch group, all switches in the circuit switching switch group are detected for abnormal conditions such as sticking, malfunction, and refusal to operate.

[0080] The specific embodiments described above further illustrate the technical problems, technical solutions and beneficial effects solved by the present invention. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A charging method for a charging device based on a full matrix coding mechanism, characterized in that: In the full matrix coding mechanism, the charging gun number is the longitude, the power module group number is the latitude, the intersection is the switch group number of the circuit switching switch group between the corresponding charging gun and the power module group, the charging gun number and the power module group number are both n, n is a natural number starting from 1, and the switch group number of the circuit switching switch group is coded and distinguished by the longitude and latitude coordinates (n, n); the steps of the method include a charging circuit switching process, and the charging circuit switching process includes a charging start process, and the charging start process is: Charging gun n starts charging, specifies power module group n, specifies the circuit switching switch group and closes its corresponding circuit switching switch group (n, n), locks the charging circuit composed of the corresponding charging gun, the specified power module group and the specified corresponding circuit switching switch group for charging; wherein, charging gun n is the charging gun with charging gun number n, power module group n is the power module group with power module group number n, and circuit switching switch group (n, n) is the circuit switching switch group with switch group number (n, n); The specific process of starting charging is as follows: S11: Charging gun n starts charging. When the corresponding charging gun is connected to the electric authorization, charging starts, and the charging circuit locking process is started to enter step S12; S12: Specifying a dedicated power module group n: Specifying a dedicated power module group number n according to the charging gun number n, and proceeding to step S13; S13: Determine whether the power module group n is working: if it is working, go to step S14, otherwise go to step S15; S14: All loop switch groups in the n-dimensional power module group are operated separately, and the process goes to step S15; S15: The circuit switch group of the power module group n and the charging gun n that intersects the longitude and latitude is combined and operated, and the process proceeds to step S16; S16: Lock the power module group n and the charging circuit start module of the charging gun n to charge; The charging circuit switching process also includes the detection of the demand of charging gun n and the process of increasing and decreasing the charging circuit: that is, when the power demand of charging gun n changes in steps and the absolute value of the change is greater than the power of the power module group, the charging circuit between the idle and low-frequency power module group and the charging gun n is increased in turn according to the positive and negative changes, that is, the corresponding circuit switching switch group is closed or the charging circuit between the high-frequency power module group and the charging gun n other than the exclusive power module group n is reduced in turn, that is, the corresponding circuit switching switch group is divided; Charging gun n demand detection, the charging circuit increase and decrease process is as follows: S21: Charging gun n demand detection: Charging gun n demand change detection, increase or decrease the charging circuit according to the change amount, and enter step S22; S22: specifying the power difference between the required charging power and the actual output power; S23: Determine whether the absolute value of the power difference is greater than the power of the power module group. If the absolute value of the power difference is less than the power, the existing charging circuit is maintained and the process ends. If the absolute value of the power difference is greater than the power, the process proceeds to step S24. S24: Determine whether the power difference is a positive number, if it is a positive number, proceed to step S25, if it is a negative number, proceed to step S26; S25: Add charging circuit: If there is no idle power module group, no charging circuit is added to maintain the status quo and charge balance to end this process; if there is an idle power module group, select the charging circuit composed of the idle power module group with the lowest usage frequency and charging gun n, close all switches under the corresponding circuit switching switch group to add a charging circuit to start the power module group to supplement the charging power and improve the charging efficiency; S26: Reduce charging circuits: Select the most frequently used power module group other than the dedicated power module group and the charging gun n to form a charging circuit, and operate all switches under the corresponding circuit switching switch group to reduce the charging circuit, turn off the power module group, adjust the charging power, and provide other charging guns with the charging efficiency. The charging circuit switching process also includes a charging circuit release process when charging gun n ends charging, that is, when charging gun n ends charging, all circuit switching switch groups in the charging gun number dimension are disconnected to release the charging circuit for the next charging; When charging gun n finishes charging, the charging circuit release process is as follows: S31: Charging gun n ends charging: When charging gun n stops charging, the charging circuit release process starts and enters step S32; S32: The circuit switching switch group of the charging gun n that intersects the longitude and latitude is operated separately. The circuit switching switch group of the charging gun n that intersects the longitude and latitude is the circuit switching switch group on all power module groups and the charging circuit of the charging gun n. All switches in the circuit switching switch group are disconnected to restore the charging circuits of all charging guns n to prepare for the next charging, and then enter step S33; S33: The charging circuit stop module is restored to stop charging.

2. The charging method according to claim 1, characterized in that: The charging gun number, the power module group number and the corresponding switch group number have the following corresponding relationship: switch group number = (power module group number-1)×number of charging guns + charging gun number; wherein the number of charging guns is the number of charging guns of the charging device.

3. The charging method according to claim 1, characterized in that: The method also includes the following steps: performing a safety detection process while switching the charging circuit, the safety detection process including: charging gun safety detection and / or power module group safety detection and / or circuit switching switch group safety detection.

4. The charging method according to claim 3, characterized in that: If an abnormal state occurs during the safety detection process, the corresponding charging circuit will be disconnected immediately to ensure charging safety; And / or in the charging gun safety test, detect the charging gun over-temperature, over-voltage, over-current, insulation, BMS, and communication abnormality; And / or in the power module group safety detection, detect the over-temperature, communication, and out-of-control abnormal states of all modules in the power module group; And / or in the safety detection of the circuit switching switch group, detect the abnormal states of adhesion, malfunction and refusal to operate of all switches in the circuit switching switch group.

5. A charging device, characterized in that: The charging method according to any one of claims 1 to 4 is implemented.

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