WO2021134990A1 - Method, apparatus and system for controlling grid connection of distributed energy storage power source - Google Patents

Abstract

A method, apparatus and system for controlling grid connection of a distributed energy storage power source. The method comprises: acquiring a distributed energy storage power source grid connection control instruction (S201); in response to the distributed energy storage power source grid connection control instruction, determining the current working condition of a distributed energy storage power source (S202); acquiring voltage values of various energy storage power source units in the distributed energy storage power source under the current working condition (S203); and controlling grid connection of the various energy storage power source units on the basis of the voltage values of the various energy storage power source units and a preset voltage difference threshold value (S204). In the solution, a grid connection control method suitable for a distributed energy storage mode is provided to realize distributed energy storage; and according to the distributed energy storage solution, each vehicle carries an energy storage power source unit corresponding thereto, such that the problem of flexibly grouping energy storage allocation can be successfully solved.

Description

Method, device and system for controlling grid connection of distributed energy storage power supply

This application claims the priority of a Chinese patent application filed with the Chinese Patent Office on January 02, 2020, the application number is 202010001391.4, and the invention title is "Methods, Devices and Systems for Controlling the Grid Connection of Distributed Energy Storage Power Sources". The entire content is incorporated into this application by reference.

Technical field

This application relates to the field of rail transit technology, and more specifically, to a method, device and system for controlling the grid connection of distributed energy storage power sources.

Background technique

With the continuous development of urban construction, people's demand for public transportation is constantly escalating, from the initial solution to basic needs, and the gradual transition to the pursuit of comfort and environmental protection. Trams and trolleybuses are two important means of transportation to solve urban road public transportation. In recent years, modern trams and trolley buses have transitioned from high floors in the past to 100% low floors, and from the past catenary power supply methods to The vehicle-mounted energy storage power supply mode has gradually transitioned from a single formation in the past to an ultra-long flexible formation.

At present, the on-board energy storage power supply method usually adopted by trams or trolley buses is centralized energy storage. However, centralized energy storage places energy storage power sources in a centralized manner, and the included electric energy reserves can meet the current marshalling length. Flexible marshalling, that is, increasing or reducing the number of vehicles will make the current electric energy reserve insufficient or excessive, and the structure of the energy storage power supply needs to be changed. Therefore, centralized energy storage cannot meet the long and flexible marshalling needs of trams and trolley buses. .

Therefore, how to provide a vehicle-mounted energy storage and power supply method that meets the needs of ultra-long and flexible marshalling of trams and trolley buses has become a technical problem to be solved urgently by those skilled in the art.

Summary of the invention

In view of the above-mentioned problems, the present application is proposed to provide a method, device and system for controlling the grid connection of distributed energy storage power sources that overcomes the above-mentioned problems or at least partially solves the above-mentioned problems. The specific plan is as follows:

A method for controlling grid connection of distributed energy storage power sources, the method comprising:

Obtain the grid-connected control instruction of distributed energy storage power supply;

In response to the grid-connected control instruction of the distributed energy storage power supply, determining the current working condition of the distributed energy storage power supply;

Acquiring the voltage value of each energy storage power supply unit in the distributed energy storage power supply under the current working condition;

Based on the voltage value of each energy storage power supply unit and a preset voltage difference threshold value, the energy storage power supply unit is controlled to be connected to the grid.

Optionally, the determining the current operating condition of the distributed energy storage power supply includes:

Determine whether the emergency charging switch signal is received;

If the emergency charging switch signal is received, determining that the current operating condition of the distributed energy storage power source is an emergency charging operating condition;

If the emergency charging switch signal is not received, determining whether the emergency discharging switch signal is received;

If the emergency discharge switch signal is received, determining that the current working condition of the distributed energy storage power source is an emergency discharge working condition;

If the emergency charging switch signal is not received, and the emergency discharging switch signal is not received, it is determined that the current operating condition of the distributed energy storage power source is a normal operating condition.

Optionally, when the current operating condition is the emergency charging operating condition, the controlling the grid connection of each energy storage power supply unit based on the voltage value of each energy storage power supply unit and a preset voltage difference threshold includes :

Perform the following steps several times until all the energy storage power supply units are connected to the grid:

Determine a first energy storage power supply unit and a second energy storage power supply unit, where the first energy storage power supply unit is the energy storage power supply unit with the lowest voltage value among the energy storage power supply units; the second energy storage power supply unit is The energy storage power supply unit with the second lowest voltage value among the energy storage power supply units;

Controlling the grid connection of the first energy storage power supply unit, and charging the first energy storage power supply unit;

When the difference between the charged voltage value of the first energy storage power supply unit and the voltage value of the second energy storage power supply unit is less than or equal to the preset voltage difference threshold, the second energy storage power supply unit is controlled to be connected to the grid.

Optionally, when the current operating condition is the emergency discharge operating condition, the controlling the grid connection of each energy storage power supply unit based on the voltage value of each energy storage power supply unit and a preset voltage difference threshold includes :

Perform the following steps several times until all the energy storage power supply units are connected to the grid:

Determine a third energy storage power supply unit and a fourth energy storage power supply unit, where the third energy storage power supply unit is the energy storage power supply unit with the highest voltage value among the energy storage power supply units; the fourth energy storage power supply unit is The energy storage power supply unit with the second highest voltage value among the energy storage power supply units;

Controlling the third energy storage power supply unit to connect to the grid, and discharging the third energy storage power supply unit;

When the difference between the voltage value of the third energy storage power supply unit after discharge and the voltage value of the fourth energy storage power supply unit is less than or equal to the preset voltage difference threshold, the fourth energy storage power supply unit is controlled to be connected to the grid.

Optionally, when the current operating condition is the normal operating condition, the controlling the grid connection of each energy storage power supply unit based on the voltage value of each energy storage power supply unit and a preset voltage difference threshold includes:

According to the voltage value of each energy storage power supply unit, determine whether there are a preset number of energy storage power supply units with a voltage value greater than a preset minimum voltage value for traction in each energy storage power supply unit;

If it exists, perform the following steps several times until all the energy storage power supply units are connected to the grid for power supply:

A fifth energy storage power supply unit and a sixth energy storage power supply unit are determined, where the fifth energy storage power supply unit is the energy storage power supply unit with the highest voltage value among the energy storage power supply units; the sixth energy storage power supply unit is The energy storage power supply unit with the second highest voltage value among the energy storage power supply units;

Judging whether the fifth energy storage power supply unit meets a preset grid connection condition;

If it is satisfied, control the fifth energy storage power supply unit to connect to the grid, and use the fifth energy storage power supply unit to supply power;

When the difference between the voltage value of the fifth energy storage power supply unit after being supplied with power and the voltage value of the sixth energy storage power supply unit is less than or equal to the preset voltage difference threshold, it is determined whether the sixth energy storage power supply unit meets the preset requirements. Set up grid connection conditions;

If it is satisfied, the sixth energy storage power supply unit is controlled to be connected to the grid for power supply.

Optionally, judging whether the energy storage power supply unit meets preset grid connection conditions, including:

Acquiring the current voltage value of the energy storage power supply unit;

Judging whether the current voltage value is lower than a preset unusable voltage value;

If it is not lower than, it is determined that the energy storage power supply unit meets the preset grid-connection condition;

If it is lower than, it is determined that the energy storage power supply unit does not meet the preset grid connection condition.

Optionally, judging whether the energy storage power supply unit meets preset grid connection conditions, including:

Acquiring capacitance state information of the energy storage power supply unit;

Judging whether the capacitance state information is normal;

If it is normal, it is determined that the energy storage power supply unit meets the preset grid-connection condition;

If it is not normal, it is determined that the energy storage power supply unit does not meet the preset grid connection condition.

Optionally, judging whether the energy storage power supply unit meets preset grid connection conditions, including:

Acquiring the number of opening and closing times of the contactor of the energy storage power supply unit;

Judging whether the number of opening and closing times of the contactor reaches a preset threshold;

If not, it is determined that the energy storage power supply unit meets the preset grid-connection condition;

If it reaches, it is determined that the energy storage power supply unit does not meet the preset grid-connection condition.

A device for controlling the grid connection of distributed energy storage power sources, the device comprising:

Instruction acquisition unit for acquiring distributed energy storage power supply grid-connected control instructions;

A working condition determining unit, configured to determine the current working condition of the distributed energy storage power source in response to the grid-connected control instruction of the distributed energy storage power source;

A voltage value acquisition unit, configured to acquire the voltage value of each energy storage power supply unit in the distributed energy storage power supply under the current working condition;

The grid-connected control unit is configured to control the grid-connected of each energy storage power supply unit based on the voltage value of each energy storage power supply unit and a preset voltage difference threshold.

A system for controlling the grid connection of distributed energy storage power supplies, which is applied to multi-group trains composed of N independent vehicles connected together, where N is an integer greater than or equal to 2;

The system for controlling the grid-connected distributed energy storage power supply includes a vehicle controller, an input and output module, electrical equipment, and a distributed energy storage power supply. The distributed energy storage power supply includes each independent The energy storage power supply unit on the vehicle; the vehicle controller is used to execute the method for controlling the grid-connected distributed energy storage power supply as described above.

With the above technical solutions, the present application discloses a method, device and system for controlling the grid connection of distributed energy storage power sources, and obtains the grid connection control instructions of the distributed energy storage power sources; Network control instructions to determine the current operating condition of the distributed energy storage power supply; obtain the voltage value of each energy storage power supply unit in the distributed energy storage power supply under the current operating condition; The voltage value and the preset voltage difference threshold control the grid connection of each energy storage power supply unit. In the above scheme, a grid-connected control method suitable for distributed energy storage is proposed to realize distributed energy storage. In the distributed energy storage scheme, each vehicle carries a corresponding energy storage power supply unit, which can well Solve the problem of flexible organization of energy storage distribution.

The above description is only an overview of the technical solution of this application. In order to understand the technical means of this application more clearly, it can be implemented in accordance with the content of the specification, and in order to make the above and other purposes, features and advantages of this application more obvious and understandable. , The specific implementations of this application are cited below.

Description of the drawings

By reading the detailed description of the preferred embodiments below, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only used for the purpose of illustrating the preferred embodiments, and are not considered as a limitation to the application. Also, throughout the drawings, the same reference symbols are used to denote the same components. In the attached picture:

Fig. 1 is a schematic diagram of a system for controlling the grid connection of distributed energy storage power sources disclosed in an embodiment of the application;

FIG. 2 is a schematic flowchart of a method for controlling the grid connection of distributed energy storage power sources disclosed in an embodiment of the application;

Fig. 3 is a schematic structural diagram of a device for controlling the grid connection of distributed energy storage power sources disclosed in an embodiment of the application.

Detailed ways

Hereinafter, exemplary embodiments of the present disclosure will be described in more detail with reference to the accompanying drawings. Although the drawings show exemplary embodiments of the present disclosure, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

Please refer to Figure 1. Figure 1 is a schematic diagram of a system for controlling the grid connection of distributed energy storage power sources disclosed in an embodiment of the application, which is applied to a multi-marshalling train. As shown in Figure 1, the multi-marshalling train is articulated. The through passage is formed by connecting N independent vehicles. The multi-group train can be composed of N railcars or N trolleybuses, where N is an integer greater than or equal to 2.

The system used to control the grid-connected distributed energy storage power supply includes the vehicle controller (VCU as shown in the figure), input and output modules (IOU as shown in the figure), and electrical equipment (as shown in the figure). Motor controller), and distributed energy storage power supply, as an implementable manner, the distributed energy storage power supply includes energy storage power supply units (such as installed on the top of the vehicle) installed on each independent vehicle. CMS1, CMS2,..., CMSN shown in the figure). The vehicle controller, input and output modules, electrical equipment, and distributed energy storage power sources transmit information to each other through a network system (CAN network as shown in the figure).

Specifically, each energy storage power supply unit is equipped with an independent energy management system (not shown in the figure), and each energy management system is used to manage the charging and discharging of the corresponding energy storage power supply unit, and is also used to manage the corresponding storage power supply unit. The status information of the power supply unit (such as voltage, current, etc.) is monitored, and the monitored status information is transmitted to the vehicle controller through the on-board network system.

The vehicle controller is used to control the disconnection and disconnection of the first contactor (K1, K2,..., Kn shown in the figure) integrated in each energy storage power supply unit through the input and output module according to the status information of each energy storage power supply unit closure. For example, when the vehicle controller determines that the energy storage power supply unit is faulty according to the status information of a certain energy storage power supply unit, it can control the first contactor integrated in the energy storage power supply unit to be disconnected through the input and output module. The energy storage power supply unit is isolated, and other non-faulty energy storage power supply units are connected to the grid for power supply to ensure the normal operation of multiple marshalling trains.

In the system for controlling the grid-connected distributed energy storage power supply, the first contactor is electrically connected to the second contactor integrated in the electrical equipment of the multi-group tram (Km11, Km12, Km21, Km22 shown in the figure) ), and the third contactor integrated in the emergency charging socket (Ke1, Ke2 shown in the figure).

When the vehicle controller determines that it is necessary to supply power to some electrical equipment of the multi-marshalling electric car according to the status information of each energy storage power supply unit, and to stop power supply to other electrical equipments of the multi-marshalling electric car, it can control some users through the input and output modules The second contactor of the electrical equipment is closed, and the second contactor of other electrical equipment is controlled to open.

In emergency situations such as severe undervoltage of the distributed energy storage power supply of multi-marshalling trams, or when multi-marshalling trams need to be charged and discharged for maintenance in the garage, the vehicle controller is connected to the charging and discharging device on the ground through the emergency charging socket Then the third contactor integrated in the emergency charging socket is controlled to close through the input and output module to charge and discharge the energy storage power supply of the multi-group tram.

Each energy storage power supply unit is integrated with an independent fuse (not shown in the figure), which is used to prevent the corresponding energy storage power supply unit from being damaged by high current charging and discharging.

Based on the above system for controlling the grid-connected distributed energy storage power supply, when the faulty energy storage power supply is reset or restored after the failure of the energy storage power supply, because other non-faulty energy storage power supplies have been supplying power to the vehicle, the voltage will be reduced. The voltage of the energy power supply unit will be higher than the voltage of other energy storage power supply units. In this case, there will be a problem that the energy storage power supply voltage difference may cause the energy storage power supply unit's fuse to burn out. In addition, in other situations, such as emergency charging and discharging, replacement of energy storage power supply units, re-marshalling of multi-marshalling trams, etc., there will also be a problem that the voltage difference of the energy storage power supply may cause the fuse to burn out.

In order to solve the above-mentioned problems, this application discloses a method for controlling the grid connection of distributed energy storage power sources. Based on this method, the problem of fuse burnout caused by the voltage difference of distributed energy storage power sources in multi-marshalling trams can be effectively avoided. The method for controlling the grid connection of distributed energy storage power sources disclosed in the present application will be described in detail below through the following embodiments.

Please refer to Figure 2. Figure 2 is a schematic flow diagram of a method for controlling the grid connection of distributed energy storage power sources disclosed in an embodiment of the application. The execution body of the method can be used to control the grid connection of distributed energy storage power sources. The vehicle controller of the system, the method includes the following steps:

S201: Obtain a grid-connected control instruction of the distributed energy storage power supply.

In this application, the distributed energy storage power supply grid-connected control command can be generated by the driver by triggering preset controls in the multi-group train, and transmitted to the vehicle controller through the network system.

S202: In response to the grid-connected control instruction of the distributed energy storage power supply, determine the current operating condition of the distributed energy storage power supply.

After the vehicle controller obtains the distributed energy storage power grid-connected control command, it responds to it and determines the current working condition of the distributed energy storage power source. The current working condition of the distributed energy storage power source is the current working condition of the multi-group train. As an implementable method, the current operating conditions of the distributed energy storage power supply include special operating conditions and normal operating conditions. Among them, the special operating conditions include emergency charging operating conditions and emergency discharging operating conditions.

In this application, the emergency charging/discharging working condition is a special working condition, requiring the driver to press the emergency charging/discharging switch signal to enter the emergency charging/discharging working condition for multi-group trains, otherwise, it is a normal working condition.

As an implementable manner, determining the current operating condition of the distributed energy storage power supply includes: determining whether an emergency charging switch signal is received; if the emergency charging switch signal is received, determining the distributed energy storage power supply If the emergency charging switch signal is not received, determine whether the emergency discharge switch signal is received; if the emergency discharge switch signal is received, determine whether the distributed energy storage power source is The current working condition is an emergency discharge working condition; if the emergency charging switch signal is not received, and the emergency discharge switch signal is not received, it is determined that the current working condition of the distributed energy storage power supply is a normal working condition.

S203: Acquire the voltage value of each energy storage power supply unit in the distributed energy storage power supply under the current working condition.

The voltage value of each energy storage power supply unit in the distributed energy storage power supply can be collected by the energy management system of each energy storage power supply unit and sent to the vehicle controller through the network system.

S204: Control the grid connection of each energy storage power supply unit based on the voltage value of each energy storage power supply unit and a preset voltage difference threshold.

In order to ensure that the fuse will not burn out, according to Kirchhoff power supply theory, before controlling the energy storage power supply to the grid, first obtain the voltage value U _{H of the energy storage power supply with the highest voltage and the voltage value U L} of the energy storage power supply with the lowest voltage. The difference U _H- U _L , and, the sum of the resistance of the two energy storage power supplies and the line resistance R _All , the quotient of the two must be less than the maximum allowable current I _{Fuse of the} fuse, namely:

According to the above formula, it is determined that ΔU=U _H -U _L is the preset voltage difference threshold value when the distributed energy storage power source is connected to the grid in the system for controlling the distributed energy storage power source to be connected to the grid.

It should be noted that there are different grid-connected control strategies under different working conditions, which will not be repeated in this embodiment, and the details will be described in detail through the following embodiments.

This embodiment discloses a method for controlling the grid-connection of distributed energy storage power supplies to obtain a distributed energy storage power grid-connected control command; in response to the distributed energy storage power grid-connected control command, determine the distributed energy storage power supply grid-connected control command. The current working condition of the energy storage power supply; obtain the voltage value of each energy storage power supply unit in the distributed energy storage power supply under the current working condition; control based on the voltage value of each energy storage power supply unit and a preset voltage difference threshold The various energy storage power supply units are connected to the grid. In the above scheme, a grid-connected control method suitable for distributed energy storage is proposed to realize distributed energy storage. In the distributed energy storage scheme, each vehicle carries a corresponding energy storage power supply unit, which can well Solve the problem of flexible grouping of energy storage distribution.

The following is a detailed introduction to different grid-connected control strategies under different working conditions.

It should be noted that the emergency charging conditions must satisfy that the emergency charging socket is connected to the charging and discharging device on the ground. The judgment basis for the good connection is to short-circuit the 24V positive through the emergency charging socket. The 24V positive signal collected by the IOU indicates that the emergency charging socket has been connected. ; Then, based on the voltage value of each energy storage power supply unit and the preset voltage difference threshold to determine the grid connection sequence of each energy storage power supply unit, and finally, based on the grid connection sequence of each energy storage power supply unit to control the respective energy storage The power supply unit is connected to the grid.

As an implementable manner, when the current operating condition is the emergency charging operating condition, the control of each energy storage power supply unit based on the voltage value of each energy storage power supply unit and a preset voltage difference threshold value Net, including:

Perform the following steps several times until all the energy storage power supply units are connected to the grid:

Determine a first energy storage power supply unit and a second energy storage power supply unit, where the first energy storage power supply unit is the energy storage power supply unit with the lowest voltage value among the energy storage power supply units; the second energy storage power supply unit is The energy storage power supply unit with the second lowest voltage value among the energy storage power supply units;

Controlling the grid connection of the first energy storage power supply unit, and charging the first energy storage power supply unit;

When the difference between the charged voltage value of the first energy storage power supply unit and the voltage value of the second energy storage power supply unit is less than or equal to the preset voltage difference threshold, the second energy storage power supply unit is controlled to be connected to the grid.

Examples such as:

On the premise that the emergency charging conditions are met, there are voltage differences between multiple energy storage power supply units, and all contactors of the energy storage power supply unit need to be disconnected for safety. At this time, the voltage values of the multiple energy storage power supply units are sorted, and the one with the lowest voltage value U _{min of the} energy storage power supply unit can first close the first contactor and perform emergency charging on it. During the charging process, compare the lowest voltage value U _min with the second lowest voltage value U _min+1 to obtain the difference ΔU ₁ =U _min+1 -U _min , and then determine _{whether the difference ΔU 1} is less than or equal to ΔU, That is, ΔU ₁ ≤ΔU. If the conditions are met, the contactor of the energy storage power supply unit with the second lowest voltage value is closed, and emergency charging is carried out together. Otherwise, wait for the energy storage power supply unit with the lowest voltage value to charge until the condition is met before closing the contactor of the energy storage power supply unit with the second lowest voltage value. And so on, until all the contactors of the energy storage power supply unit are closed.

It should be noted that the emergency discharge conditions must satisfy that the emergency charging socket is connected to the charging and discharging device on the ground. The basis for judging that the connection is good is to short-circuit the 24V positive through the emergency charging socket. The 24V positive signal collected by the IOU indicates that the emergency charging socket has been connected. ; Then, based on the voltage value of each energy storage power supply unit and the preset voltage difference threshold to determine the grid connection sequence of each energy storage power supply unit, and finally, based on the grid connection sequence of each energy storage power supply unit to control the respective energy storage The power supply unit is connected to the grid.

As an implementable manner, when the current operating condition is the emergency discharge operating condition, the energy storage power supply unit is controlled based on the voltage value of each energy storage power supply unit and a preset voltage difference threshold value. Net, including:

Perform the following steps several times until all the energy storage power supply units are connected to the grid:

Determine a third energy storage power supply unit and a fourth energy storage power supply unit, where the third energy storage power supply unit is the energy storage power supply unit with the highest voltage value among the energy storage power supply units; the fourth energy storage power supply unit is The energy storage power supply unit with the second highest voltage value among the energy storage power supply units;

Controlling the third energy storage power supply unit to connect to the grid, and discharging the third energy storage power supply unit;

When the difference between the discharged voltage value of the third energy storage power supply unit and the voltage value of the fourth energy storage power supply unit is less than or equal to the preset voltage difference threshold, the fourth energy storage power supply unit is controlled to be connected to the grid.

Examples such as:

On the premise that the emergency discharge conditions are met, there are voltage differences between multiple energy storage power supply units, and all contactors of the energy storage power supply unit need to be disconnected for safety. At this time, the voltage values of the multiple energy storage power supply units are sorted, and the highest voltage value of the energy storage power supply unit U _max can first close the contactor to perform emergency discharge. Then compare the highest voltage value U _max with the second highest voltage value U _max-1 to obtain the difference, ΔU ₁ =U _max -U _max-1 , and then determine _{whether the difference ΔU 1} is less than or equal to ΔU, that is, ΔU ₁ ≤ΔU. If the conditions are met, the contactor of the second highest voltage value of the energy storage power supply unit is closed, and emergency discharge is performed together. Otherwise, continue to discharge the energy storage power supply unit with the highest voltage value until the condition is met before closing the contactor of the energy storage power supply unit with the second highest voltage value. By analogy, until all the contactors of the energy storage power supply unit with available voltage are closed, emergency discharge.

The normal operating condition is usually the vehicle operating mode. Therefore, the distributed energy storage power supply unit system at this time at least satisfies that the voltage of two or more energy storage power supply units is greater than the minimum allowable traction voltage U _a , which is a prerequisite for the energy storage power supply unit as a grid-connected power supply.

As an implementable manner, when the current operating condition is the normal operating condition, the grid-connected control of each energy storage power supply unit is based on the voltage value of each energy storage power supply unit and a preset voltage difference threshold. ,include:

According to the voltage value of each energy storage power supply unit, determine whether there are a preset number of energy storage power supply units with a voltage value greater than a preset minimum voltage value for traction in each energy storage power supply unit;

If it exists, perform the following steps several times until all the energy storage power supply units are connected to the grid for power supply:

Determine a fifth energy storage power supply unit and a sixth energy storage power supply unit, where the fifth energy storage power supply unit is the energy storage power supply unit with the highest voltage value among the energy storage power supply units; the sixth energy storage power supply unit is The energy storage power supply unit with the second highest voltage value among the energy storage power supply units;

Judging whether the fifth energy storage power supply unit meets a preset grid connection condition;

If it is satisfied, control the fifth energy storage power supply unit to connect to the grid, and use the fifth energy storage power supply unit to supply power;

When the difference between the voltage value of the fifth energy storage power supply unit and the voltage value of the sixth energy storage power supply unit is less than or equal to the preset voltage difference threshold, it is determined whether the sixth energy storage power supply unit satisfies the preset Set up grid connection conditions;

If it is satisfied, the sixth energy storage power supply unit is controlled to be connected to the grid for power supply.

Examples such as:

Under the premise of meeting the preset grid connection conditions, there are voltage differences among multiple energy storage power supply units. For safety, all contactors of the energy storage power supply unit need to be disconnected. At this time, the voltage values of the multiple energy storage power supply units are sorted, and the highest voltage value U _{max of the} energy storage power supply unit can first close the contactor and connect to the grid for power supply. Then compare the highest voltage value U _max with the second highest voltage value U _max-1 to obtain the difference, ΔU ₁ =U _max -U _max-1 , and then determine _{whether the difference ΔU 1} is less than or equal to the set threshold ΔU, That is, ΔU ₁ ≤ΔU. If the conditions are met, the contactor of the second highest voltage value of the energy storage power supply unit is closed, and the power supply is connected to the grid together. Otherwise, continue to use the energy storage power supply unit with the highest voltage value until the condition is met before closing the contactor of the energy storage power supply unit with the second highest voltage value. And so on, until all the contactors of the energy storage power supply unit with available voltage are closed and connected to the grid for power supply.

As an implementable way, judging whether the energy storage power supply unit meets the preset grid connection conditions, including:

Acquiring the current voltage value of the energy storage power supply unit;

Judging whether the current voltage value is lower than a preset unusable voltage value;

If it is not lower than, it is determined that the energy storage power supply unit meets the preset grid-connection condition;

If it is lower than, it is determined that the energy storage power supply unit does not meet the preset grid connection condition.

The unavailable voltage of the energy storage power supply unit is only unavailable in the normal operation mode, and the preset unavailable voltage value U _{una of the} energy storage power supply unit should be less than the available voltage value, that is, U _una <U _a .

The availability and unavailability of the energy storage power supply unit directly includes a voltage buffer ΔU _buff (the size depends on the specific conditions of the vehicle), the purpose of which is to avoid the instantaneous drop of the voltage caused by high-power startup during operation, and the voltage rises when the operation is stable , The power contactor oscillates on and off at this time.

Among them, the current energy storage power supply unit is already in a grid-connected power supply state, and the voltage of the energy storage power supply unit will be reduced during the power supply process. When its voltage is lower than the available voltage U _a , you need to consider disconnecting the energy storage power supply unit and perform an emergency Recharge.

The disconnection mechanism when the power supply voltage is unavailable is:

If the voltage of the energy storage power supply unit is lower than the available voltage U _a , a low-voltage warning of the energy storage power supply unit is sent to the driver;

Reduce the power load of the vehicle, turn off electrical equipment such as air conditioners, reduce vehicle traction, etc., and drive to the emergency charging location;

When arriving at the emergency charging location or the voltage of the energy storage power supply unit is lower than the unavailable voltage U _una , disconnect the contactor of the energy storage power supply unit and enter the emergency charging mode.

As an implementable way, judging whether the energy storage power supply unit meets the preset grid connection conditions, including:

Acquiring capacitance state information of the energy storage power supply unit;

Judging whether the capacitance state information is normal;

If it is normal, it is determined that the energy storage power supply unit meets the preset grid-connection condition;

If it is not normal, it is determined that the energy storage power supply unit does not meet the preset grid connection condition.

It should be noted that the communication between the current energy storage power supply unit system and the vehicle control unit is normal, the capacitor has no serious or moderate failure, and the external grid-connected contactor has no failure, etc., which indicates that the current energy storage power unit capacitor status is allowed. Otherwise, the capacitance state is not allowed.

As yet another implementable manner, judging whether the energy storage power supply unit meets the preset grid connection conditions, including:

Acquiring the number of opening and closing times of the contactor of the energy storage power supply unit;

Judging whether the number of opening and closing times of the contactor reaches a preset threshold;

If not, it is determined that the energy storage power supply unit meets the preset grid-connection condition;

If it reaches, it is determined that the energy storage power supply unit does not meet the preset grid-connection condition.

It should be noted that during the use of a single energy storage power supply unit, if frequent faults cause the contactor to separate, and then the fault is reset, so that the contactor is closed too many times. If the number of times exceeds the limit, the energy storage is considered The power supply unit has safety issues, and the driver needs to be warned and the contactor is prohibited from closing before the entire energy storage power supply unit system restarts to ensure safety.

In summary, under normal operating conditions, it is first necessary to determine whether the current energy storage power supply unit capacitor voltage is OK. If so, it is a prerequisite for grid-connected power supply under normal operating conditions. Otherwise, the energy storage power supply unit needs to be charged, and then the threshold calculation is performed to determine the grid connection sequence of a single energy storage power supply, and finally the capacitance state, the electrical state and the number of contactor opening and closing times are respectively judged to determine whether the current energy storage power supply unit meets the conditions , If all conditions are met, the current energy storage power supply unit contactor is closed, grid connection is successful, and electricity consumption under normal working conditions is realized. Otherwise, the contactor is separated and the energy storage power supply unit is not integrated into the power grid.

Please refer to FIG. 3. FIG. 3 is a schematic structural diagram of a device for controlling the grid connection of a distributed energy storage power source disclosed in an embodiment of the application, and the device includes:

The instruction acquisition unit 31 is configured to acquire a distributed energy storage power supply grid-connected control instruction;

The working condition determining unit 32 is configured to determine the current working condition of the distributed energy storage power source in response to the grid-connected control instruction of the distributed energy storage power source;

The voltage value obtaining unit 33 is configured to obtain the voltage value of each energy storage power supply unit in the distributed energy storage power supply under the current working condition;

The grid connection control unit 34 is configured to control the grid connection of each energy storage power supply unit based on the voltage value of each energy storage power supply unit and a preset voltage difference threshold.

It should be noted that the specific function implementation of the foregoing units has been described in detail in the method embodiment, and will not be repeated in this embodiment.

Those skilled in the art should understand that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, this application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, this application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes.

This application is described with reference to flowcharts and/or block diagrams of methods, devices (systems), and computer program products according to embodiments of this application. It should be understood that each process and/or block in the flowchart and/or block diagram, and the combination of processes and/or blocks in the flowchart and/or block diagram can be realized by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing equipment to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing equipment are generated It is a device that realizes the functions specified in one process or multiple processes in the flowchart and/or one block or multiple blocks in the block diagram.

These computer program instructions can also be stored in a computer-readable memory that can guide a computer or other programmable data processing equipment to work in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture including the instruction device. The device implements the functions specified in one process or multiple processes in the flowchart and/or one block or multiple blocks in the block diagram.

These computer program instructions can also be loaded on a computer or other programmable data processing equipment, so that a series of operation steps are executed on the computer or other programmable equipment to produce computer-implemented processing, so as to execute on the computer or other programmable equipment. The instructions provide steps for implementing the functions specified in one process or multiple processes in the flowchart and/or one block or multiple blocks in the block diagram.

In a typical configuration, the computing device includes one or more processors (CPUs), input/output interfaces, network interfaces, and memory.

The memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and/or non-volatile memory, such as read-only memory (ROM) or flash memory (flash RAM). The memory is an example of a computer-readable medium.

Computer-readable media include permanent and non-permanent, removable and non-removable media, and information storage can be realized by any method or technology. The information can be computer-readable instructions, data structures, program modules, or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, CD-ROM, digital versatile disc (DVD) or other optical storage, Magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage devices or any other non-transmission media can be used to store information that can be accessed by computing devices. According to the definition in this article, computer-readable media does not include transitory media, such as modulated data signals and carrier waves.

It should also be noted that the terms "include", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or equipment including a series of elements not only includes those elements, but also includes Other elements that are not explicitly listed, or also include elements inherent to such processes, methods, commodities, or equipment. If there are no more restrictions, the element defined by the sentence "including a..." does not exclude the existence of other identical elements in the process, method, commodity, or equipment that includes the element.

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

The above are only examples of the application, and are not used to limit the application. For those skilled in the art, this application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this application shall be included in the scope of the claims of this application.

Claims (10)

1. A method for controlling the grid connection of distributed energy storage power sources, characterized in that the method includes:

   Obtain the grid-connected control instruction of distributed energy storage power supply;

   In response to the grid-connected control instruction of the distributed energy storage power supply, determining the current working condition of the distributed energy storage power supply;

   Acquiring the voltage value of each energy storage power supply unit in the distributed energy storage power supply under the current working condition;

   Based on the voltage value of each energy storage power supply unit and a preset voltage difference threshold value, the energy storage power supply unit is controlled to be connected to the grid.
2. The method according to claim 1, wherein the determining the current operating condition of the distributed energy storage power source comprises:

   Determine whether the emergency charging switch signal is received;

   If the emergency charging switch signal is received, determining that the current operating condition of the distributed energy storage power source is an emergency charging operating condition;

   If the emergency charging switch signal is not received, determining whether the emergency discharging switch signal is received;

   If the emergency discharge switch signal is received, determining that the current working condition of the distributed energy storage power source is an emergency discharge working condition;

   If the emergency charging switch signal is not received, and the emergency discharging switch signal is not received, it is determined that the current operating condition of the distributed energy storage power source is a normal operating condition.
3. The method according to claim 2, wherein when the current operating condition is the emergency charging operating condition, the control of the battery is based on the voltage value of each energy storage power supply unit and a preset voltage difference threshold. All energy storage power supply units are connected to the grid, including:

   Perform the following steps several times until all the energy storage power supply units are connected to the grid:

   Determine a first energy storage power supply unit and a second energy storage power supply unit, where the first energy storage power supply unit is the energy storage power supply unit with the lowest voltage value among the energy storage power supply units; the second energy storage power supply unit is The energy storage power supply unit with the second lowest voltage value among the energy storage power supply units;

   Controlling the grid connection of the first energy storage power supply unit, and charging the first energy storage power supply unit;

   When the difference between the charged voltage value of the first energy storage power supply unit and the voltage value of the second energy storage power supply unit is less than or equal to the preset voltage difference threshold, the second energy storage power supply unit is controlled to be connected to the grid.
4. The method according to claim 2, characterized in that, when the current operating condition is the emergency discharge operating condition, the control of the voltage difference is based on the voltage value of each energy storage power supply unit and a preset voltage difference threshold. All energy storage power supply units are connected to the grid, including:

   Perform the following steps several times until all the energy storage power supply units are connected to the grid:

   Determine a third energy storage power supply unit and a fourth energy storage power supply unit, where the third energy storage power supply unit is the energy storage power supply unit with the highest voltage value among the energy storage power supply units; the fourth energy storage power supply unit is The energy storage power supply unit with the second highest voltage value among the energy storage power supply units;

   Controlling the third energy storage power supply unit to connect to the grid, and discharging the third energy storage power supply unit;

   When the difference between the discharged voltage value of the third energy storage power supply unit and the voltage value of the fourth energy storage power supply unit is less than or equal to the preset voltage difference threshold, the fourth energy storage power supply unit is controlled to be connected to the grid.
5. The method according to claim 2, wherein when the current operating condition is the normal operating condition, the control of each of the energy storage power supply units is based on the voltage value of each energy storage power supply unit and a preset voltage difference threshold. The energy storage power supply unit is connected to the grid, including:

   According to the voltage value of each energy storage power supply unit, determine whether there are a preset number of energy storage power supply units with a voltage value greater than a preset minimum voltage value for traction in each energy storage power supply unit;

   If it exists, perform the following steps several times until all the energy storage power supply units are connected to the grid for power supply:

   Determine a fifth energy storage power supply unit and a sixth energy storage power supply unit, where the fifth energy storage power supply unit is the energy storage power supply unit with the highest voltage value among the energy storage power supply units; the sixth energy storage power supply unit is The energy storage power supply unit with the second highest voltage value among the energy storage power supply units;

   Judging whether the fifth energy storage power supply unit meets a preset grid connection condition;

   If it is satisfied, control the fifth energy storage power supply unit to connect to the grid, and use the fifth energy storage power supply unit to supply power;

   When the difference between the voltage value of the fifth energy storage power supply unit and the voltage value of the sixth energy storage power supply unit is less than or equal to the preset voltage difference threshold, it is determined whether the sixth energy storage power supply unit satisfies the preset Set up grid connection conditions;

   If it is satisfied, the sixth energy storage power supply unit is controlled to be connected to the grid for power supply.
6. The method according to claim 5, wherein determining whether the energy storage power supply unit satisfies a preset grid connection condition comprises:

   Acquiring the current voltage value of the energy storage power supply unit;

   Judging whether the current voltage value is lower than a preset unusable voltage value;

   If it is not lower than, it is determined that the energy storage power supply unit meets the preset grid-connection condition;

   If it is lower than, it is determined that the energy storage power supply unit does not meet the preset grid connection condition.
7. The method according to claim 5, wherein determining whether the energy storage power supply unit satisfies a preset grid connection condition comprises:

   Acquiring capacitance state information of the energy storage power supply unit;

   Judging whether the capacitance state information is normal;

   If it is normal, it is determined that the energy storage power supply unit meets the preset grid-connection condition;

   If it is not normal, it is determined that the energy storage power supply unit does not meet the preset grid connection condition.
8. The method according to claim 5, wherein determining whether the energy storage power supply unit satisfies a preset grid connection condition comprises:

   Acquiring the number of opening and closing times of the contactor of the energy storage power supply unit;

   Judging whether the number of opening and closing times of the contactor reaches a preset threshold;

   If not, it is determined that the energy storage power supply unit meets the preset grid-connection condition;

   If it reaches, it is determined that the energy storage power supply unit does not meet the preset grid-connection condition.
9. A device for controlling the grid connection of distributed energy storage power sources is characterized in that the device includes:

   Instruction acquisition unit for acquiring distributed energy storage power supply grid-connected control instructions;

   A working condition determining unit, configured to determine the current working condition of the distributed energy storage power source in response to the grid-connected control instruction of the distributed energy storage power source;

   A voltage value acquisition unit, configured to acquire the voltage value of each energy storage power supply unit in the distributed energy storage power supply under the current working condition;

   The grid-connected control unit is configured to control the grid-connected of each energy storage power supply unit based on the voltage value of each energy storage power supply unit and a preset voltage difference threshold.
10. A system for controlling the grid connection of distributed energy storage power sources, which is characterized in that it is applied to multi-group trains, which is composed of N independent vehicles connected, where N is an integer greater than or equal to 2 ；

    The system for controlling the grid-connected distributed energy storage power supply includes a vehicle controller, input and output modules, electrical equipment, and a distributed energy storage power supply. The distributed energy storage power supply includes separate installations in each independent The energy storage power supply unit on the vehicle; the vehicle controller is used to implement the method for controlling the grid-connected distributed energy storage power supply according to any one of claims 1 to 8.

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