CN108075536A - Flexible charging regulation and control method for charging pile and charging pile system - Google Patents

Abstract

The invention discloses a flexible charging control method for charging piles and a charging pile system, specifically including a flexible charging control method for charging piles and a charging pile system with a flexible charging control function. Inter-ad hoc network communication, real-time monitoring of the charging power of the charging pile, automatic control of the charging power of the pile body, so that the sum of the power values of the charging piles in the area is less than the rated power of the transformer, realizing orderly charging, flexible control, and reducing the charging behavior of electric vehicles. impact on the grid. The invention takes the charging station or the charging pile under the special transformer as the unit, and under the condition of meeting the regional charging load demand, the charging station and the regional charging pile under the special transformer can dispatch the load, automatically balance and adjust the maximum power of the charging pile in the area, and ensure the special charging in the charging station. The transformer will not be overloaded, realizing the orderly charging of electric vehicles and the safe and economical operation of the distribution network.

Description

Flexible charging control method of charging pile and charging pile system

technical field

The invention relates to the technical field of electric vehicle charging, in particular to a flexible charging control method for a charging pile and a charging pile system.

Background technique

As an important way of low-carbon transportation, electric vehicles have become the focus of scientific research institutions at home and abroad because of their high efficiency and low pollution. The charging of a small number of electric vehicles will not have a great impact on the grid, but large-scale access to the grid will bring challenges to the normal operation and control of the grid. It is estimated that the number of electric vehicles in my country will reach 60 million by 2030. Calculated according to the charging power of 10 kW/vehicle, assuming that these electric vehicles are charged at the same time, the peak power will reach 500 million kilowatts, resulting in a sharp increase in grid load and affecting grid operation. and controls have a non-negligible impact. Due to the different users, the behavior of electric vehicle users and the charging time have great uncertainty, resulting in a large randomness in the charging load of electric vehicles, which makes it more difficult to control the power grid; a large number of electric vehicles connected to the power grid will It will lead to load growth, increase the peak-to-valley difference of power grid load, increase the difficulty of power grid peak regulation, increase the burden on the power system, and have a serious impact on the safety and reliability of the power grid. In addition, electric vehicle charging piles are non-linear devices, which will cause large harmonic pollution to the power supply system, resulting in a decrease in power factor and adverse effects on the quality of power supply; electric vehicle charging will make the load, investment and operation of the distribution network The cost increases rapidly, and problems such as voltage loss and three-phase imbalance occur at the same time.

Therefore, it is necessary to study the impact of electric vehicle charging on the grid load, take corresponding measures for the specific impact, and implement an orderly charging method to adapt to the large-scale development of electric vehicles. The impact of electric vehicle charging on the grid load mainly has the following two aspects. On the one hand, it affects the distribution network: the charging of electric vehicles during the peak period of electricity consumption will have an important impact on the load balance, three-phase balance and voltage regulation of the distribution network. Influence, lead to overload of distribution network lines, increased loss, voltage drop and overload of distribution transformers, which will reduce the effectiveness and reliability of power grid operation. On the other hand, the impact on power quality: electric vehicles use on-board or off-board power electronic charging equipment to perform two-way conversion charging and discharging operations, so it is easy to generate harmonic pollution and damage power quality, especially during peak power consumption periods. It will increase the burden on the power supply system.

Because electric vehicle charging is an emerging industry, the current technology is not mature enough, and ordinary charging piles do not have the function of flexible charging power regulation, and can only realize basic charging functions.

Contents of the invention

The aim of the present invention is to solve at least one of the problems mentioned above.

According to the first aspect of the present invention, there is provided a flexible charging control method for charging piles, which includes multiple charging piles, and the multiple charging piles are connected through a wireless network. The method specifically includes the following steps:

1) Set one charging pile among multiple charging piles in a control cycle as the main control device, and the other charging piles as controlled devices;

2) The main control device collects the actual power data of the multiple charging piles, and calculates the real-time total power of the charging piles P _{charging pile (actual)} according to the actual power data of the multiple charging piles;

3) Determine whether the real-time total power of the charging pile P _{charging pile (actual)} is greater than the rated power of the transformer

P _{transformer (rated)} ;

If yes, execute steps 4)-5), if not, return to step 2);

4) Adjusting the maximum power of the multiple charging piles;

5) Judging whether the current control cycle is over;

If not, return to step 2);

If so, end the current regulation cycle and start a new regulation cycle.

Compared with the existing technology, the flexible charging control method of the charging pile takes the charging station or the charging pile under the special transformer as the unit. Under the condition that the regional charging load demand is met, the charging station and the regional charging pile under the special transformer can dispatch the load, automatically Balance the maximum power of the charging piles in the area to ensure that the special transformers in the charging stations will not be overloaded, and realize the orderly charging of electric vehicles and the safe and economical operation of the distribution network.

In some embodiments, in the step 2), the multiple charging piles monitor their own power data in real time, and data transmission and reception are performed between the multiple charging piles through a wireless cellular network (ZigBee).

In some implementations, the controlled device includes a relay device and a slave device; the collection of the actual power data of the multiple charging piles by the master device includes: the slave device monitors its own actual power data, and The actual power data of itself is transmitted to the master control device through the relay device or directly to the master control device; the relay device transmits its own actual power data and the actual power data transmitted from the slave device to the master control device together.

In some embodiments, the step 4) specifically includes: the main control device issues an operation instruction for flexible charging regulation; after the controlled device checks that the main control device issues an operation instruction for flexible charging regulation, Execute to adjust the maximum power of the charging pile.

As an optimization of the technical solution of the present invention, in the new control cycle, any controlled device in the previous control cycle is used as the master control device, and the master control device in the previous control cycle is used as the controlled device, and so on.

In order to achieve the purpose of the present invention, as the same inventive concept, according to the second aspect of the present invention, a charging pile system with flexible charging control function is provided, the system includes a plurality of charging piles, and the charging piles are connected through a wireless network ;In a control cycle, one of the multiple charging piles is the main control device, and the other charging piles are controlled devices; the main control device is used to monitor its own actual power data in real time and collect the controlled The actual power data of the equipment, and calculate the real-time total power of the charging pile P _{charging pile (actual)} according to the actual power data of itself and the controlled equipment, and judge whether to implement the above charging pile according to the total power P _{of the charging pile (actual)} The maximum power of multiple charging piles is adjusted.

In some embodiments, the master device and the controlled device have the function of monitoring their own power data in real time, and data transmission and reception are performed between the master device and the controlled device through a wireless cellular network (ZigBee).

In some implementations, the controlled device includes a relay device and a slave device, the slave device is used to monitor its own actual power data in real time, and transmit its own actual power data to the master control device or directly The relay device is used to monitor its own actual power data in real time, and transmits its own actual power data and the actual power data transmitted from the slave device to the master control device.

In some embodiments, the determining whether to adjust the maximum power of the multiple charging piles according to the total power of charging piles P _{charging piles (actual)} specifically includes: when the total power of charging piles P _{charging piles (actual)} > transformer When the rated power P _{transformer (rated)} , the maximum power of each charging pile in the area is lowered; when the total power of the charging pile P _{charging pile (actual)} ≤ the rated power of the transformer P _{transformer (rated)} , the maximum power of each charging pile No adjustments are made.

In some implementation manners, in the current regulation cycle, any controlled device in the previous regulation cycle serves as the master device, and the master device in the previous regulation cycle acts as the controlled device.

Compared with the existing technology, the charging pile systems in the above-mentioned embodiments monitor the charging power of the charging piles in real time through the self-organizing network communication between the charging piles, and automatically control the charging power of the charging piles, so that the sum of the power values of the charging piles in the area P _{charging pile (actual)} < transformer rated power P _{transformer (rated)} , to achieve orderly charging, flexible control, and reduce the impact of electric vehicle charging behavior on the distribution network.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. Those skilled in the art can also obtain other drawings based on these drawings without creative work.

Fig. 1 is a flow chart of the flexible charging control method of the charging pile in the embodiment of the present invention;

Fig. 2 is a schematic diagram of a charging pile module in an embodiment of the present invention;

Fig. 3 is a schematic diagram of a charging pile system with a flexible charging control function in an embodiment of the present invention;

Fig. 4 is a schematic diagram of the flexible charging equalization control method in the embodiment of the present invention;

Fig. 5 is a schematic diagram of the framework of the charging station and the charging pile under the special transformer in the embodiment of the present invention;

Fig. 6 is a schematic diagram of the components of the charging pile in the embodiment of the present invention;

Fig. 7 is a schematic diagram of a charging pile control terminal module in an embodiment of the present invention.

Detailed ways

Embodiments of the present invention are described in detail below, examples of which are shown in the drawings, wherein the same or similar reference numerals designate the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the figures are exemplary only for explaining the present invention and should not be construed as limiting the present invention.

The following disclosure provides many different embodiments or examples for implementing different structures of the present invention. To simplify the disclosure of the present invention, components and arrangements of specific examples are described below. Of course, they are only examples and are not intended to limit the invention. Furthermore, the present invention may repeat reference numerals and/or letters in different instances. This repetition is for the purpose of simplicity and clarity and does not in itself indicate a relationship between the various embodiments and/or arrangements discussed. In addition, various specific process and material examples are provided herein, but one of ordinary skill in the art will recognize the applicability of other processes and/or the use of other materials. Additionally, configurations described below in which a first feature is "on" a second feature may include embodiments where the first and second features are formed in direct contact, and may include additional features formed between the first and second features. For example, such that the first and second features may not be in direct contact.

In the description of the present invention, it should be noted that unless otherwise specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a mechanical connection or an electrical connection, or it can be two The internal communication of each element may be directly connected or indirectly connected through an intermediary. Those skilled in the art can understand the specific meanings of the above terms according to specific situations.

These and other aspects of embodiments of the invention will become apparent with reference to the following description and drawings. In these descriptions and drawings, some specific implementations of the embodiments of the present invention are specifically disclosed to represent some ways of implementing the principles of the embodiments of the present invention, but it should be understood that the scope of the embodiments of the present invention is not limited by this limit. On the contrary, the embodiments of the present invention include all changes, modifications and equivalents coming within the spirit and scope of the appended claims.

The following describes the detailed description according to the embodiments of the present invention with reference to the accompanying drawings.

Fig. 1 is a flowchart of a flexible charging control method for a charging pile provided by an embodiment of the present invention. The flexible charging control method for a charging pile is suitable for charging a charging pile in an electric vehicle charging station, and the electric vehicle charging station uses a dedicated transformer. And the rated capacity of the special transformer is known, and the load type under the special transformer is only connected to the charging pile. The electric vehicle charging station is connected with a plurality of charging piles, and the charging piles are connected through a wireless network.

Specifically, in the embodiment of the present invention, the flexible charging control method of the charging pile includes the following steps:

1) Set one charging pile among multiple charging piles in a control cycle as the main control device, and the other charging piles as controlled devices;

2) The main control device collects the actual power data of the multiple charging piles, and calculates the real-time total power of the charging piles P _{charging pile (actual)} according to the actual power data of the multiple charging piles;

3) Determine whether the real-time total power of the charging pile P _{charging pile (actual)} is greater than the rated power of the transformer

P _{transformer (rated)} ;

If yes, execute steps 4)-5), if not, return to step 2);

4) Adjusting the maximum power of the multiple charging piles;

5) Determine whether the current control cycle is over; if not, return to step 2); if yes, end the current control cycle and start a new control cycle.

Wherein, the length of the one control cycle is specifically set according to the actual control situation.

In an embodiment of the present invention, preferably, the multiple charging piles can monitor their own power data in real time, and data transmission and reception are performed between the multiple charging piles through a wireless cellular network (ZigBee). Among them, ZigBee is a wireless connection that can work in three frequency bands of 2.4GHz (popular in the world), 868MHz (popular in Europe) and 915 MHz (popular in the United States), with a maximum of 250kbit/s, 20kbit/s and 40kbit/s respectively. The transmission rate, its transmission distance is in the range of 10-75m, but it can continue to increase. ZigBee features low power consumption, low cost, short delay, large network capacity, reliability and security.

In this embodiment, the functional module composition of the charging pile is shown in Figure 2, which specifically includes a charging billing unit, a charging controller, and a charging power supply module. The flexible charging control method of this embodiment is based on the charging pile It is developed on the basis of the charging and charging control unit in which the charging and charging unit, the charging controller and the charging power supply module are connected and communicated through the CAN bus in turn. Wherein, the step 4) adjusting the maximum power of the plurality of charging piles is specifically to send an instruction through the charging billing unit to make the charging controller control the charging module to adjust the power.

In an embodiment of the present invention, preferably, the controlled device includes a relay device and a slave device. The purpose of setting the controlled device in this way is to avoid direct long-distance wireless transmission, and to improve the efficiency of data transmission through relay transition. reliability and stability.

In this embodiment, the master control device collecting the actual power data of the plurality of charging piles includes: the slave device monitors its own actual power data, and transmits its own actual power data to the master control device via a relay device Or directly transmit to the master control device; the relay device transmits its own actual power data and the actual power data transmitted from the slave device to the master control device together.

In an embodiment of the present invention, as a preference, the step 4) specifically includes: the master control device issues an operation instruction for performing flexible charging regulation; the controlled device checks that the master control device issues a flexible charging instruction After adjusting the operation command, execute and adjust the maximum power of the charging pile.

In this embodiment, the balanced control method is used to flexibly regulate all charging piles, including the main control device and the controlled device. The principle of the balanced control method is shown in Figure 4. Specifically, the balanced control method refers to all charging piles Maximum power is adjusted with the same proportional reduction.

In one embodiment of the present invention, as a preference, in the new control cycle, any controlled device in the previous control cycle is used as the master device, and the master device in the previous control cycle is used as the controlled device, and so on. cycle.

A flexible charging control method for charging piles according to an embodiment of the present invention takes charging stations or charging piles under special transformers as a unit, and under the condition that regional charging load requirements are met, charging stations and regional charging piles under special transformers can dispatch loads, automatically Balance the maximum power of the charging piles in the area to ensure that the special transformers in the charging stations will not be overloaded, and realize the orderly charging of electric vehicles and the safe and economical operation of the distribution network.

Fig. 3 is another embodiment of the present invention, a schematic diagram of a wireless ad-hoc network system of charging piles in a regulation cycle of a charging pile system with a flexible charging control function. The charging pile system with flexible charging control function is suitable for charging piles of electric vehicle charging stations. The electric vehicle charging station uses a special transformer, and the rated capacity of the special transformer is known. The load type of the special transformer is only connected to the charging pile. . It can be seen from FIG. 3 that in this embodiment, the system includes multiple charging piles, and the connection between the multiple charging piles is established through a wireless cellular network (ZigBee).

In one control cycle, one charging pile among the multiple charging piles is the main control device, and the other charging piles are controlled devices; the main control device monitors its own actual power data in real time and collects the actual power data of the controlled devices. Power data, and calculate the real-time total power of charging pile P _{charging pile (actual)} according to the actual power data of itself and the controlled equipment, and judge whether to execute the multiple charging according to the total power of charging pile P _{charging pile (actual)} Adjust the maximum power of the pile.

In an embodiment of the present invention, preferably, the master device and the controlled device have the function of real-time monitoring of their own power data, and the data transmission between the master device and the controlled device is carried out through a wireless cellular network (ZigBee) and receive.

In an embodiment of the present invention, preferably, the controlled device includes a relay device and a slave device, and the slave device monitors its own actual power data in real time, and transmits its own actual power data to the master device through the relay device The relay device monitors its own actual power data in real time, and transmits its own actual power data and the actual power data transmitted from the slave device to the master control device.

In an embodiment of the present invention, preferably, the judging whether to adjust the maximum power of the multiple charging piles according to the total power of the charging pile P _{charging pile (actual)} specifically includes: when the total power of the charging pile

When P _{charging pile (actual)} > transformer rated power P _{transformer (rated)} , reduce the maximum power of each charging pile in the area; when the total power of charging pile P _{charging pile (actual)} ≤ transformer rated power P _{transformer (rated)} , The maximum power of each charging pile is not adjusted.

In an embodiment of the present invention, as a preference, in the current control cycle, any controlled device in the previous control cycle is used as the master control device to judge the control strategy, and the master control device in the previous control cycle is used as the controlled device .

In one embodiment of the present invention, as a preference, each charging pile is assigned a code. When a new charging pile is added in the area, as long as the charging pile code is assigned according to the rules, the main control device can automatically join the ad hoc network system. . The following describes the ad hoc network in combination with actual cases. For example, 9000540035 is a 60kw single-gun DC pile in Futian Lianhuashan. Before each charging pile goes online, a unique pile code will be set in the billing control unit in the charging pile to identify charging. Pile identity information. For example, if the newly added pile is set to 9000770032 and does not belong to the charging pile assigned to the station, it cannot be added to the system. When the number of charging piles decreases or fails, the system will generate a corresponding fault message. According to the fault message, the system will automatically isolate the charging pile, prohibit the charging pile from starting to charge, and wait for the maintenance to be normal before releasing the isolation state.

Charging piles are divided into DC charging piles and AC charging piles, and the methods and systems in the above-mentioned multiple embodiments are suitable for DC charging piles. The composition modules of the charging piles in the above-mentioned multiple embodiments are shown in Figure 6. The charging piles The pile includes a power unit, a charging pile control terminal module, a charging controller, a meter, a charging interface, and a human-computer interaction interface, wherein the charging interface is preferably a charging gun.

Specifically, the charging pile control terminal module is a charging pile control and billing device, which is connected to the electrical part as shown in Figure 7, and is mainly controlled through the CAN bus. In addition to the billing and billing functions in the name, the charging pile control terminal module also has man-machine interface display, multi-function meter interaction, 3G/4G car networking platform interaction, and charging device controller interaction. The main functions of the charging pile control terminal module are: 1. Payment method selection, you can choose to pay by card, or you can choose other online payment methods such as WeChat Alipay payment. 2. Cost metering, the charging pile control terminal module is connected to the meter through the 485 interface, and the electricity required for charging the electric vehicle needs to be aggregated to the charging pile control terminal module. The flexible charging control method of the charging pile in the method and system in the above-mentioned multiple embodiments is implemented in this device.

In a specific embodiment of the present invention, as shown in Figure 5, the method for flexible charging control of the charging pile of the present invention is applied to the implementation of the charging pile under the special transformer charging station. Specifically, in this charging station, The load type under the dedicated transformer is only connected to the charging pile. Figure 5 shows multiple charging piles installed with dedicated transformers in one area. In the embodiment of the present invention, charging codes are assigned in the background to distinguish control areas.

In this specific embodiment, a charging pile with a flexible charging control strategy method is installed under the charging station or a single dedicated transformer. The rated capacity of the dedicated transformer is known, and the rated capacity of a dry-type transformer is 800KVA, and the dedicated transformer Under the premise that only charging piles are connected, the power consumption of charging piles is divided into two types: 7kW low-power AC charging piles and 60kW DC charging piles.

Therefore, the charging available maximum power of the charging station is:

P _(Maximum) = (800KVA*0.9)*0.8=720*0.8=576kW

If there is no charging pile with a flexible charging control strategy method, then when installing the charging pile, you can only estimate the number of charging piles that can be powered on and run, and only nine 60kW DC charging piles can be installed in this area to start charging. .

If a charging pile with _a flexible charging control strategy is installed, at least 12 60kW DC charging piles can be installed to start charging. Power P _{transformer (rated)} , according to the balance control method, the charging pile is flexibly regulated, and the maximum power of all charging piles is uniformly adjusted. Using the charging pile flexible charging equalization control method, the rated power of the charging pile is reduced to 80% according to the calculation. The schematic diagram of the principle of the pile flexible charging equalization control method is shown in Figure 4. After the flexible charging equalization control, the actual power of the charging pile is as follows:

P _{charging pile (actual)} = P _{transformer (load)} = (60Kw*12)*80%=576Kw

It can be seen that after using the method or system of the present invention, when multiple charging piles start charging at the same time and the power of the charging piles exceeds the rated power of the transformer, the actual load of the transformer can be effectively reduced to ensure safe and economical operation of the distribution network. The embodiment of the present invention takes the charging station or the charging pile under the special transformer as the unit. Under the condition of meeting the regional charging load demand, the charging station and the regional charging pile under the special transformer can dispatch the load, and automatically balance and adjust the maximum power of the charging pile in the area to ensure charging. The special transformer in the station will not be overloaded, realizing the orderly charging of electric vehicles and the safe and economical operation of the distribution network.

Any process or method descriptions in flowcharts or otherwise described herein may be understood to represent modules, segments or portions of code comprising one or more executable instructions for implementing specific logical functions or steps of the process , and the scope of preferred embodiments of the invention includes alternative implementations in which functions may be performed out of the order shown or discussed, including substantially concurrently or in reverse order depending on the functions involved, which shall It is understood by those skilled in the art to which the embodiments of the present invention pertain.

The logic and/or steps represented in the flowcharts or otherwise described herein, for example, can be considered as a sequenced listing of executable instructions for implementing logical functions, can be embodied in any computer-readable medium, For use with an instruction execution system, device, or device (such as a computer-based system, a system including a processor, or other systems that can fetch instructions from an instruction execution system, device, or device and execute instructions), or in conjunction with such an instruction execution system, device or equipment used. For the purposes of this specification, a "computer-readable medium" may be any device that can contain, store, communicate, propagate or transmit a program for use in or in conjunction with an instruction execution system, device or device. More specific examples (non-exhaustive list) of computer-readable media include the following: electrical connection with one or more wires (electronic device), portable computer disk case (magnetic device), random access memory (RAM), Read Only Memory (ROM), Erasable and Editable Read Only Memory (EPROM or Flash Memory), Fiber Optic Devices, and Portable Compact Disc Read Only Memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program can be printed, since the program can be read, for example, by optically scanning the paper or other medium, followed by editing, interpretation or other suitable processing if necessary. The program is processed electronically and stored in computer memory.

It should be understood that various parts of the present invention can be realized by hardware, software, firmware or their combination. In the embodiments described above, various steps or methods may be implemented by software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented by any one or combination of the following techniques known in the art: Discrete logic circuits, ASICs with suitable combinational logic gates, Programmable Gate Arrays (PGAs), Field Programmable Gate Arrays (FPGAs), etc.

Those of ordinary skill in the art can understand that all or part of the steps carried by the methods of the above embodiments can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium. During execution, one or a combination of the steps of the method embodiments is included.

In addition, each functional unit in each embodiment of the present invention may be integrated into one processing module, each unit may exist separately physically, or two or more units may be integrated into one module. The above-mentioned integrated modules can be implemented in the form of hardware or in the form of software function modules. If the integrated modules are realized in the form of software function modules and sold or used as independent products, they can also be stored in a computer-readable storage medium.

The storage medium mentioned above may be a read-only memory, a magnetic disk or an optical disk, and the like.

In the description of this specification, descriptions referring to the terms "one embodiment", "some embodiments", "example", "specific examples", or "some examples" mean that specific features described in connection with the embodiment or example , structure, material or characteristic is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Although the embodiments of the present invention have been shown and described, those skilled in the art can understand that various changes, modifications and substitutions can be made to these embodiments without departing from the principle and spirit of the present invention. and modifications, the scope of the invention is defined by the appended claims and their equivalents.

Claims (10)

1. A method for controlling flexible charging of a charging pile, comprising a plurality of charging piles connected by a wireless network, characterized in that the method comprises the following steps: Step 1) Set one charging pile among multiple charging piles in a control cycle as the master control device, and the other charging piles as controlled devices; Step 2) The main control device collects the actual power data of the multiple charging piles, and calculates the real-time total power of the charging piles P _{charging pile (actual)} according to the actual power data of the multiple charging piles; Step 3) Determine whether the real-time total charging pile power P _{charging pile (actual)} is greater than the rated power of the transformer P _{transformer (rated)} ; If yes, execute steps 4)-5), if not, return to step 2); Step 4) Adjusting the maximum power of the multiple charging piles; Step 5) Judging whether the current control cycle is over; If not, return to step 2); If so, end the current regulation cycle and start a new regulation cycle. 2. The flexible charging control method for charging piles according to claim 1, characterized in that, in the step 2), the multiple charging piles monitor their own power data in real time, and the charging piles between the multiple charging piles Data transmission and reception via wireless cellular network (ZigBee). 3. A flexible charging control method for a charging pile according to claim 1 or 2, wherein the controlled device includes a relay device and a slave device; The collection of the actual power data of the plurality of charging piles by the main control device includes: the slave device monitors its own actual power data, and transmits its own actual power data to the main control device through a relay device or directly to the main control device device; the relay device transmits its own actual power data and the actual power data transmitted from the slave device to the master device. 4. A flexible charging control method for charging piles according to claim 1 or 2, characterized in that the step 4) specifically includes: The main control device issues an operation instruction for flexible charging regulation; The controlled device adjusts the maximum power of the charging pile after checking that the main control device issues an operation instruction for flexible charging regulation. 5. A flexible charging control method for charging piles according to claim 4, characterized in that in step 5), in the new control cycle, any controlled device in the previous control cycle is used as the main control device, the master device of the previous control cycle is used as the controlled device, and so on. 6. A charging pile system with a flexible charging control function, the system includes a plurality of charging piles, and the charging piles are connected through a wireless network, characterized in that, In one control cycle, one charging pile among the plurality of charging piles is the main control device, and the other charging piles are controlled devices; The main control device is used to monitor its own actual power data in real time and collect the actual power data of the controlled device, and calculate the real-time total power of the charging pile P _{charging pile (actual)} according to the actual power data of itself and the controlled device , and according to the total power P of charging _{piles (actual),} it is judged whether to adjust the maximum power of the multiple charging piles. 7. A charging pile system with a flexible charging control function according to claim 6, wherein the main control device and the controlled device have the function of real-time monitoring of their own power data, and the main control device and the controlled device Data is transmitted and received between devices through a wireless cellular network (ZigBee). 8. A charging pile system with a flexible charging control function according to claim 6 or 7, wherein the controlled device includes a relay device and a slave device, and the slave device is used for real-time monitoring of its own actual Power data, and transmit its own actual power data to the master control device through the relay device or directly to the master control device; the relay device is used to monitor its own actual power data in real time, and transmit its own actual power data The transmitted actual power data is also transmitted to the main control device. 9. A charging pile system with a flexible charging control function according to claim 8, characterized in that, according to the total power of the charging pile P _{charging pile (actual),} it is judged whether to implement the maximum Power adjustments specifically include: When the total power of charging piles P charging pile > transformer rated power P transformer, the maximum power of each charging pile in the area is lowered; When the total power of charging piles P charging pile ≤ transformer rated power P transformer, the maximum power of each charging pile is not adjusted. 10. A charging pile system with flexible charging control function according to claim 6, characterized in that, in the current control cycle, any controlled device in the previous control cycle is used as the main control device, and the last control cycle The master control device is the controlled device.