Optical storage and charging cooperative regulation system and method based on communication protocol conversion

Abstract

The application provides a photovoltaic energy storage and charging cooperative regulation system and method based on communication protocol conversion, comprising: a device terminal layer, including a photovoltaic unit, an energy storage unit and a charging pile unit, the three units respectively communicate externally according to the device side communication protocol; a protocol conversion layer, including a protocol conversion device connected with each unit of the device terminal layer, to convert the operation data and control instructions of the corresponding unit between the device side communication protocol and the unified communication protocol; a data transmission layer, used for forwarding the operation data and control instructions in the unified communication protocol between the protocol conversion layer and the regulation center layer; a regulation center layer, used for receiving the operation data of the device terminal layer; and generating the control instructions of each unit of the device terminal layer according to the operation data, and issuing the control instructions to the protocol conversion layer through the data transmission layer. The technical method provided by the application can improve the convenience of the cooperative operation of photovoltaic, energy storage and charging pile to a certain extent.

Description

Technical Field

[0001] This invention relates to the field of power system technology, and in particular to a photovoltaic-storage-charging coordinated control system and method based on communication protocol conversion. Background Technology

[0002] With the rapid development of new power systems, a large number of distributed photovoltaic (PV) systems, energy storage systems, and charging piles are being connected to the grid. In a typical distribution network, distributed PV systems convert DC power to AC power via PV inverters before connecting to the grid. Energy storage batteries use energy storage converters to achieve bidirectional conversion between DC and AC power for charging and discharging management. Charging piles provide charging services for electric vehicles.

[0003] However, different types of distributed devices use different communication protocols. Specifically, photovoltaic inverters mostly use the Modbus-RTU protocol, energy storage converters support the Modbus-RTU protocol, and charging piles use the CAN bus protocol, while the power industry standard communication protocol is DL / T698.45. This protocol heterogeneity prevents direct interconnection between photovoltaic, energy storage, and charging pile devices, making centralized data acquisition and coordinated control difficult.

[0004] In existing technologies, some control schemes only perform localized optimizations for a single type of equipment, such as power limiting only for photovoltaic inverters or timed start-stop control only for charging piles, lacking a holistic consideration of all elements of photovoltaic, energy storage, and charging. Although some schemes involve protocol conversion devices, their functions are limited, only capable of unidirectional protocol conversion, and lack functions such as data encryption, data acquisition and storage, and local control, making it difficult to meet the security protection requirements of power monitoring systems. Summary of the Invention

[0005] The present invention provides a high-voltage live display interlocking device and method, which at least solves the technical problem that traditional photovoltaic, energy storage and charging pile equipment are difficult to operate in coordination.

[0006] In a first aspect, embodiments of the present invention provide a photoelectric storage-charging coordinated control system based on communication protocol conversion, comprising:

[0007] The equipment terminal layer includes a photovoltaic unit, an energy storage unit, and a charging pile unit. The three units communicate with the outside world according to their respective equipment-side communication protocols; among them, at least two of the three units have different equipment-side communication protocols.

[0008] The protocol conversion layer includes a protocol conversion device connected to each unit of the device terminal layer, which converts the operating data of the corresponding unit from the device-side communication protocol to the unified communication protocol and then sends it to the data transmission layer; and converts the communication protocol of the control command from the unified communication protocol to the device-side communication protocol of the corresponding unit.

[0009] The data transmission layer is communicatively connected to both the protocol conversion layer and the control center layer, and is used to forward operating data and control commands using the unified communication protocol between the protocol conversion layer and the control center layer.

[0010] The control center layer is used to receive the operating data of the device terminal layer; and to generate control instructions for each unit of the device terminal layer based on the operating data, and send them to the protocol conversion layer through the data transmission layer.

[0011] In one embodiment of the present invention, each of the protocol conversion devices has a built-in security module;

[0012] The control center layer is used to encrypt the control commands and then send them through the data transmission layer.

[0013] The protocol conversion device is used to decrypt the received encrypted control commands and then convert them from the unified communication protocol into the device-side communication protocol of the corresponding unit.

[0014] In one embodiment of the present invention, it further includes: a transformer area monitoring device;

[0015] The transformer area monitoring equipment is used to collect at least one of the following: transformer capacity, remaining capacity, load rate, and voltage and current data of transformer nodes in the transformer area; and uploads the collected data to the control center layer via the data transmission layer.

[0016] The control center layer is also used to determine the upper limit of the available charging power of the charging pile unit based on the remaining capacity of the transformer in the distribution area, and to ensure that the limit on the charging power of the charging pile unit in the generated control command does not exceed the upper limit of the available charging power.

[0017] In one embodiment of the present invention, each of the protocol conversion devices is further configured to collect and store the operating data of the corresponding unit, and report to the control center layer when an abnormal event is detected.

[0018] In one embodiment of the present invention, the device-side communication protocol of the photovoltaic unit and / or the device-side communication protocol of the energy storage unit is the Modbus-RTU protocol;

[0019] The device-side communication protocol of the charging pile unit is the CAN protocol;

[0020] The unified communication protocol is DL / T698.45.

[0021] In one embodiment of the present invention, the protocol conversion device corresponding to the charging pile unit communicates with the charging pile in the charging pile unit via a CAN bus with a resistor connected in series in a differential signal manner.

[0022] In one embodiment of the present invention, the data transmission layer includes a concentrator;

[0023] The concentrator communicates with the protocol conversion layer via power line carrier or low-power wireless, and communicates with the control center layer via a public wireless network.

[0024] In one embodiment of the present invention, the protocol conversion device corresponding to the charging pile unit has a built-in orderly charging control strategy, which is used to regulate the charging time and charging power of each charging pile in the charging pile unit according to the control instructions issued by the control center layer.

[0025] Secondly, embodiments of the present invention provide a method for coordinated control of optical storage and charging based on communication protocol conversion, wherein the method is applied to the optical storage and charging coordinated control system based on communication protocol conversion described in any of the above embodiments, and the method includes:

[0026] The system collects the operating data of the photovoltaic unit, energy storage unit, and charging pile unit in the equipment terminal layer, converts the operating data of each unit from its equipment-side communication protocol to a unified communication protocol, and uploads it to the control center layer.

[0027] The control center layer generates control commands using a unified communication protocol, which are used to control the photovoltaic unit, energy storage unit, and charging pile unit respectively, based on the respective operating data of the photovoltaic unit, energy storage unit, and charging pile unit, and sends them down to the data transmission layer.

[0028] The data transmission layer forwards control commands to the protocol conversion device corresponding to the device terminal layer.

[0029] The protocol conversion device converts the communication protocol of the control command from the unified communication protocol to the device-side communication protocol of the corresponding unit in order to control the operation of the corresponding unit.

[0030] In one embodiment of the present invention, the control center layer generates control commands, employing a unified communication protocol and used to control the photovoltaic unit, energy storage unit, and charging pile unit respectively, based on the respective operating data of the photovoltaic unit, energy storage unit, and charging pile unit. These commands include:

[0031] Based on the grid purchase cost, energy storage cycle loss cost, and grid loss cost, a comprehensive operating cost function is constructed within the scheduling cycle.

[0032] Based on the predicted power generation of the photovoltaic unit, the redundant power of the photovoltaic grid connection and the photovoltaic carbon emission reduction coefficient during the scheduling period, an emission reduction benefit function is constructed for the scheduling period.

[0033] A comprehensive objective function is constructed based on the comprehensive operating cost function and the emission reduction benefit function.

[0034] With the goal of minimizing the comprehensive objective function and the constraint set of the transformer substation as the constraint condition, control commands for the photovoltaic unit, the energy storage unit, and the charging pile unit are generated.

[0035] This invention provides a photovoltaic-storage-charging coordinated control system and method based on communication protocol conversion. By setting up a protocol conversion layer, the operating data of photovoltaic units, energy storage units, and charging pile units using different device-side communication protocols in the equipment terminal layer are uniformly converted into a unified communication protocol and then uploaded to the control center layer via the data transmission layer. The control center layer generates control commands for each unit based on the overall operating status of the distribution area and sends them to the protocol conversion layer via the data transmission layer. The protocol conversion layer then reverses the control commands of the unified communication protocol into the corresponding device-side communication protocol for each unit and controls the operation of each unit. Therefore, without large-scale modifications to existing equipment in the distribution area, the coordinated operation of distributed photovoltaic, energy storage, and charging piles can be achieved, achieving self-balancing of the distribution area, reducing line losses, and improving grid stability and renewable energy absorption rate. Attached Figure Description

[0036] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0037] Figure 1 This is a schematic diagram of the structure of a photoelectric storage and charging coordinated control system based on communication protocol conversion provided in one embodiment of the present invention.

[0038] Figure 2 This is a schematic diagram of the structure of distributed photovoltaic regulation provided in one embodiment of the present invention.

[0039] Figure 3 This is a schematic diagram of a distributed energy storage structure provided in one embodiment of the present invention.

[0040] Figure 4 This is a schematic diagram of the charging pile control structure provided in one embodiment of the present invention.

[0041] Figure 5 This is a schematic flowchart of a method for coordinated control of optical storage and charging based on communication protocol conversion, provided in one embodiment of the present invention. Detailed Implementation

[0042] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0043] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0044] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of this application. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0045] In a distributed photovoltaic-storage-charging network, distributed photovoltaic power is converted from direct current (DC) to alternating current (AC) by photovoltaic inverters before being fed into the grid. Energy storage batteries are converted from DC to AC via energy storage converters to perform charging or discharging. Charging stations provide DC or AC charging services for electric vehicles. Specifically, the photovoltaic inverter controls the output power of the photovoltaic array, the energy storage converter regulates the charging and discharging power and operating mode of the energy storage batteries, and the charging stations manage the charging power and charging time of the electric vehicles.

[0046] Under the existing transformer substation operation mode, the aforementioned equipment typically operates independently. Specifically, the photovoltaic inverter feeds power to the grid based on the output of its connected photovoltaic array, the energy storage converter operates according to preset charging and discharging periods, and the charging pile responds to the plug-and-charge needs of electric vehicles. There is a lack of a unified data interaction and coordinated control mechanism among the three.

[0047] One key reason for this independent operation of the devices lies in the heterogeneity of the communication protocols used by different types of distributed devices. Specifically, photovoltaic inverters mostly use the Modbus-RTU protocol, energy storage converters are compatible with the Modbus-RTU protocol, and charging piles use the CAN bus protocol, while the standard communication protocol used in the power industry for electricity consumption information collection systems is DL / T698.45. This protocol heterogeneity means that photovoltaic inverters, energy storage converters, and charging piles operate in different communication domains, preventing direct interconnection between the devices. Consequently, it is impossible to collect full operational data from each device and perform centralized coordinated control through a unified control center.

[0048] To achieve basic equipment data acquisition, some solutions employ protocol converters to convert the proprietary protocols of a single type of equipment into standard protocols. However, these protocol converters typically only support one-way protocol conversion; that is, they can only convert the device-side protocol into an uplink communication protocol to support data reporting, but cannot reverse-engineer standard protocol commands issued by the control center into a protocol recognizable by the device to achieve remote control. Furthermore, these protocol converters often lack security encryption, event logging, and local data storage capabilities, making it difficult to meet the security requirements of power monitoring systems.

[0049] Furthermore, even if the operational data of each device is aggregated to the control center, existing technologies still lack a comprehensive control strategy that balances economy, safety, and stability. Specifically, if the sole objective is to minimize operating costs, there may be significant curtailment of solar power, resulting in low utilization of photovoltaic power generation. If the sole objective is to maximize photovoltaic absorption, it may lead to frequent deep charging and discharging of energy storage devices, accelerating their lifespan degradation, or causing overload operation of transformers in distribution areas, affecting grid security.

[0050] Based on this, this application provides a photovoltaic-storage-charging coordinated control system and method based on communication protocol conversion. By setting up a protocol conversion layer, the operating data of photovoltaic units, energy storage units, and charging pile units using different device-side communication protocols in the equipment terminal layer are uniformly converted into a unified communication protocol and then uploaded to the control center layer via the data transmission layer. The control center layer generates control commands for each unit based on the overall operating status of the distribution area and sends them to the protocol conversion layer via the data transmission layer. The protocol conversion layer then reverses the control commands of the unified communication protocol into the corresponding device-side communication protocol for each unit and controls the operation of each unit. Therefore, without large-scale modifications to existing equipment in the distribution area, the coordinated operation of distributed photovoltaic, energy storage, and charging piles can be achieved, achieving self-balancing of the distribution area, reducing line losses, and improving grid stability and renewable energy absorption rate.

[0051] Please see Figure 1 This application provides a photoelectric storage and charging coordinated control system based on communication protocol conversion.

[0052] The photovoltaic-storage-charging coordinated control system is a system used for unified monitoring and coordinated control of distributed photovoltaic, energy storage, and charging piles within a distribution area. Specifically, the photovoltaic-storage-charging coordinated control system can be applied to distribution networks in areas containing distributed photovoltaic power generation, energy storage devices, and electric vehicle charging piles. The embodiments in this application are not specifically limited herein.

[0053] The photovoltaic-storage-charging coordinated control system comprises an equipment terminal layer, a protocol conversion layer, a data transmission layer, and a control center layer. These four layers are interconnected sequentially, forming a closed-loop process of data acquisition, protocol conversion, command issuance, and equipment control.

[0054] The equipment terminal layer is the collection of physical devices within the transformer substation that directly participate in the generation, storage, and consumption of electricity. Specifically, the equipment terminal layer includes photovoltaic units, energy storage units, and charging pile units.

[0055] Please see Figure 2 A photovoltaic (PV) unit is a combination of power generation devices used to convert solar energy into electrical energy and feed it into the power grid. Specifically, a PV unit includes a PV array, a PV inverter, and a smart switch. The PV array converts solar energy into direct current (DC). The PV inverter, connected to the PV array, converts the DC to alternating current (AC) and adjusts the output power according to received control commands. The smart switch, connected to the output of the PV inverter, performs rigid switching operations based on on / off commands.

[0056] Please see Figure 3 An energy storage unit is a combination of devices used to store and release electrical energy. Specifically, an energy storage unit includes an energy storage battery, a battery management system, and an energy storage converter. The energy storage battery stores direct current (DC) energy. The battery management system monitors the state parameters of the energy storage battery. The energy storage converter is connected to both the energy storage battery and the power grid to control the charging and discharging operation mode and power of the energy storage battery.

[0057] Please see Figure 4 A charging station unit is a combination of devices used to provide charging services for electric vehicles. Specifically, a charging station unit includes a charging station and an electricity meter. The charging station converts alternating current (AC) into direct current (DC) adapted to the electric vehicle's battery or directly provides AC. The electricity meter is connected to the power input terminal of the charging station and is used to measure the electrical energy consumed by the charging station.

[0058] The three units communicate externally according to their respective equipment-side communication protocols. The equipment-side communication protocol is a communication protocol configured at the factory or during engineering deployment for data exchange between the unit and its local controller. At least two of the three units use different equipment-side communication protocols. For example, the photovoltaic inverter in the photovoltaic unit may use the Modbus-RTU protocol, the energy storage converter in the energy storage unit may use the Modbus-RTU protocol, and the charging pile in the charging pile unit may use the CAN protocol. Therefore, there are protocol heterogeneities between the photovoltaic unit, the energy storage unit, and the charging pile unit, preventing direct interconnection.

[0059] The protocol conversion layer is an intermediate processing layer located between the device terminal layer and the data transmission layer, used to overcome communication barriers caused by the heterogeneity of protocols among different units in the device terminal layer. Specifically, the protocol conversion layer includes protocol conversion devices connected to each unit of the device terminal layer.

[0060] A protocol conversion device is a communication processing device used to achieve bidirectional conversion between different communication protocols. Specifically, the protocol conversion device has a downlink communication interface and an uplink communication interface. The downlink communication interface is used to connect to the device-side communication interface of the corresponding unit, and the uplink communication interface is used to connect to the data transmission layer.

[0061] In the data uploading direction, the protocol conversion device is used to convert the operating data of the corresponding unit from the device-side communication protocol to the unified communication protocol before sending it to the data transmission layer. In the command issuing direction, the protocol conversion device is used to convert the communication protocol of the control command from the unified communication protocol to the device-side communication protocol of the corresponding unit, so that the corresponding unit can recognize and execute the control command.

[0062] A unified communication protocol is a communication standard commonly used between the protocol conversion layer and the data transmission layer, and between the data transmission layer and the control center layer. By unifying the communication protocols of various heterogeneous devices into a unified communication protocol, each unit at the device terminal layer, using different device-side communication protocols, can interact with the control center layer as if using the same communication language, thereby achieving centralized data acquisition and coordinated control. For example, the unified communication protocol can be the power industry standard communication protocol DL / T698.45.

[0063] The data transmission layer is a communication relay layer located between the protocol conversion layer and the control center layer, providing a transmission channel for data interaction between the two layers. Specifically, the data transmission layer is communicatively connected to both the protocol conversion layer and the control center layer. The data transmission layer forwards operational data and control commands using a unified communication protocol between the protocol conversion layer and the control center layer.

[0064] The data transmission layer may include a concentrator. A concentrator is a communication device used to aggregate data from multiple protocol conversion devices in the protocol conversion layer and interact with the control center layer via a remote communication network. Specifically, the concentrator can communicate with each protocol conversion device in the protocol conversion layer via power line carrier or low-power wireless, and communicate with the control center layer via a public wireless network. Power line carrier or low-power wireless is suitable for local communication scenarios within a distribution area, while a public wireless network is suitable for remote communication scenarios between the distribution area and a remote control center.

[0065] The control center layer is the decision-making and control core of the photovoltaic-storage-charging coordinated control system, used for global monitoring and coordinated control of the operating status of each unit in the equipment terminal layer. Specifically, the control center layer receives operating data from the equipment terminal layer, generates control commands for each unit in the equipment terminal layer based on the operating data, and sends them down to the protocol conversion layer through the data transmission layer.

[0066] The control center layer may include an electricity consumption information acquisition system. This system is a main station system used to collect, process, and monitor electricity consumption information from power users. In this embodiment, the electricity consumption information acquisition system is equipped with a photovoltaic-storage-charging coordinated control module. This module runs a coordinated control algorithm, analyzes and processes the global operating data of the distribution areas aggregated to the control center layer, generates control commands for photovoltaic units, energy storage units, and charging pile units, and monitors the execution status of each unit in response to the control commands in real time, forming a closed-loop control system.

[0067] Through the above four-layer architecture, the photovoltaic-storage-charging coordinated control system can collect electricity consumption data of distributed photovoltaic, energy storage, and charging piles in a transformer area, realize communication protocol conversion, report equipment information to the electricity consumption information collection system, and after analyzing and processing the data, the electricity consumption information collection system sends commands to control the operating status of distributed photovoltaic, energy storage, and charging piles, thereby realizing the coordinated control of photovoltaic, energy storage, and charging.

[0068] In some embodiments, each protocol conversion device has a built-in security module. The control center layer is used to encrypt control commands and then send them down through the data transmission layer. The protocol conversion device is used to decrypt the received encrypted control commands and then convert them from the unified communication protocol into the device-side communication protocol of the corresponding unit.

[0069] In this embodiment, the security module is a security chip located inside the protocol conversion device, used to implement data encryption and decryption functions. Specifically, the security module can store security credentials such as keys and digital certificates, and perform encryption and decryption processing on data using hardware-level cryptographic algorithms. For example, the security module can be an Embedded Secure Access Module (ESAM) chip. By embedding a security module in the protocol conversion device, end-to-end security protection can be provided for data interaction between the protocol conversion layer and the control center layer.

[0070] The control center layer is used to encrypt control commands before sending them through the data transmission layer. Specifically, after generating control commands for each unit, the control center layer can call an encryption algorithm that matches the security module to encrypt the control command message, generating an encrypted message. The encrypted control command is encapsulated using a unified communication protocol and forwarded through the data transmission layer to the corresponding protocol conversion device in the protocol conversion layer. Because the control command exists in encrypted form throughout the transmission process, even if the transmission channel is illegally accessed, the command content cannot be obtained or tampered with.

[0071] The protocol conversion device is used to decrypt received encrypted control commands and then convert them from the unified communication protocol to the device-side communication protocol of the corresponding unit. Specifically, after receiving the encrypted control commands issued by the control center layer, the protocol conversion device first decrypts the encrypted message through its built-in security module to recover the plaintext control commands using the unified communication protocol; then, it converts the decrypted control commands from the unified communication protocol to the device-side communication protocol compatible with the corresponding unit, and sends them to the corresponding unit for execution through the downlink communication interface.

[0072] In the above process, the protocol conversion device performs operations in the order of decryption followed by conversion. This order ensures that the protocol conversion stage processes recognizable plaintext of the unified communication protocol, rather than ciphertext, thereby guaranteeing the normal execution of the protocol conversion function.

[0073] For example, in a distributed photovoltaic (PV) control scenario, the electricity information acquisition system (control center layer) sends encrypted messages to the concentrator (data transmission layer). The concentrator forwards the encrypted object-oriented communication protocol control messages to the PV protocol converter (protocol conversion device). The ESAM chip built into the PV protocol converter decrypts the encrypted messages and then converts the decrypted object-oriented communication protocol control commands into corresponding Modbus-RTU protocol commands. These commands are then used to control the PV inverter via RS485 or Ethernet to achieve flexible control, or to achieve rigid on / off control via smart switches.

[0074] Similarly, in distributed energy storage control scenarios, the electricity information acquisition system sends encrypted messages to the concentrator. The concentrator then transparently forwards the encrypted messages to the energy storage protocol converter via power line carrier or low-power wireless. The energy storage protocol converter decrypts the object-oriented communication protocol encrypted messages sent by the concentrator and converts them into Modbus-RTU protocol commands. These commands are then used to communicate with the energy storage converter via RS485 or Ethernet to control the converter's charging and discharging operation mode and power output.

[0075] By configuring security modules for each protocol conversion device and establishing a secure transmission mechanism of "encrypted distribution - decryption and conversion" between the control center layer and the protocol conversion layer, the confidentiality and integrity of control commands during transmission in the local communication network and remote public network of the distribution area can be guaranteed, preventing commands from being stolen or tampered with, and meeting the relevant requirements for security protection of power monitoring systems.

[0076] In some embodiments, the system further includes a transformer area monitoring device. The transformer area monitoring device is used to collect at least one of the following: transformer capacity, remaining capacity, load rate, and voltage and current data of the transformer area nodes. The collected data is then uploaded to the control center layer via a data transmission layer. The control center layer is also used to determine the upper limit of the available charging power of the charging pile unit based on the remaining capacity of the transformer area, and to ensure that the charging power limit for the charging pile unit in the generated control commands does not exceed the upper limit of the available charging power.

[0077] In this embodiment, the transformer substation monitoring equipment is a monitoring device deployed at key nodes of the transformer substation power distribution network to collect real-time operating status parameters of the substation. Specifically, the transformer substation monitoring equipment may include a transformer substation load monitoring terminal. The transformer substation load monitoring terminal is installed on the low-voltage side of the transformer substation and is used to collect the transformer's capacity, real-time remaining capacity, load rate, and voltage and current data of each node on the low-voltage side.

[0078] The introduction of transformer area monitoring equipment provides the control center with real-time operational status information of the transformer area's power grid side. Unlike the power supply and load side data reported by each unit at the equipment terminal level, the transformer area monitoring equipment collects electrical parameters at the transformer area's common connection point and distribution network level, which can reflect the overall power balance and equipment operating margin of the transformer area.

[0079] Specifically, the capacity of a transformer substation is used to characterize the upper limit of the substation's power supply capacity. Remaining capacity characterizes the additional load power that the substation transformer can still carry under the current load level. The load factor characterizes the ratio between the current load level and the rated capacity of the substation transformer. Voltage and current data at each node are used to reflect the power quality and power flow distribution of the substation's distribution network.

[0080] The monitoring equipment in the distribution area uploads the collected data to the control center layer via the data transmission layer. Specifically, the monitoring equipment can transmit data to the concentrator via power line carrier or low-power wireless, and the concentrator will then forward the data to the electricity consumption information collection system via the public wireless network.

[0081] After receiving data collected by the transformer area monitoring equipment, the control center also uses it to determine the upper limit of available charging power for the charging pile units based on the remaining capacity of the transformers in the transformer area. The upper limit of available charging power is the maximum total charging power allowed for the charging pile units under the current operating conditions of the transformer area. Specifically, the control center can determine the safe charging power limit available for the charging pile units during the current dispatch period based on the remaining capacity of the transformers in the transformer area and the predicted demand of other loads in the transformer area, so as to ensure that the transformers in the transformer area do not operate under overload.

[0082] Furthermore, when generating control commands, the control center will ensure that the charging power limit for the charging pile unit in the generated control commands does not exceed the upper limit of the available charging power. Specifically, regardless of the target charging power of the charging pile obtained by the collaborative control algorithm based on operating costs and emission reduction benefits, the final issued charging power command must be verified against the upper limit of the available charging power. If the optimization result exceeds the upper limit, then the upper limit will be used as the total charging power limit for the charging pile unit.

[0083] For example, please refer to Figure 4 The intelligent monitoring terminal for charging piles incorporates an orderly charging control strategy. Upon receiving control commands from the electricity information collection system, it adjusts the charging time and power of each charging pile based on factors such as time-of-use pricing, remaining capacity of the transformer substation, charging pile power, and electric vehicle battery status. The remaining capacity of the transformer substation serves as a constraint, ensuring that the total charging power of all charging piles does not exceed the upper limit of the available charging power of the transformer substation, thus achieving flexible and safe control of the charging piles.

[0084] By setting up monitoring equipment in the transformer substation and using the remaining capacity of the transformer substation as a hard constraint on the power regulation of charging piles, orderly charging of charging piles can be achieved while ensuring the safe operation of the transformer substation. This avoids problems such as transformer overload and voltage drop caused by excessive charging load, thereby improving the stability and safety of the transformer substation operation.

[0085] In some embodiments, please refer to Figures 2 to 4 Each protocol conversion device is also used to collect and store the operating data of the corresponding unit, and to report to the control center when an abnormal event is detected.

[0086] In this embodiment, in addition to performing bidirectional protocol conversion, the protocol conversion device is also endowed with edge-side data management and event monitoring capabilities. Specifically, the protocol conversion device continuously collects the operating data of the corresponding unit at a preset sampling period through its downlink communication interface. The operating data is a set of parameters reflecting the real-time operating status of the corresponding unit. For example, for a photovoltaic unit, the operating data may include power generation, output voltage, output current, and operating temperature; for an energy storage unit, the operating data may include remaining power, charging and discharging power, voltage, current, frequency, harmonics, and temperature; for a charging pile unit, the operating data may include charging power, charging energy, and charging status.

[0087] The protocol conversion device is equipped with an internal storage module. This module is used to locally store the collected operational data. Specifically, the storage module can be a non-volatile storage device, ensuring data integrity even after power loss. By locally storing operational data, the protocol conversion device can continuously record the operational status of the corresponding unit during communication interruptions, and then retransmit the data once communication is restored, thus guaranteeing the integrity and continuity of the operational data.

[0088] An abnormal event refers to an operating state or malfunction that deviates from the normal operating range during the operation of the corresponding unit. Specifically, abnormal events can include at least one of the following event types: voltage exceeding limits, current exceeding limits, frequency abnormalities, harmonic exceeding limits, excessive temperature, communication interruption, equipment failure, and alarm triggering. The protocol conversion device is used to continuously monitor the real-time collected operating data and determine whether an abnormal event has occurred based on preset abnormality judgment conditions.

[0089] When the protocol conversion device detects an abnormal event, it also proactively reports the abnormal event information to the control center. Specifically, after detecting an abnormal event, the protocol conversion device can immediately generate an abnormal reporting message containing information such as the type of abnormal event, the time of occurrence, relevant operating data, and the event level, and send it to the control center via the data transmission layer. Unlike conventional periodic data reporting, the proactive reporting of abnormal events adopts an instantaneous triggering method, without waiting for polling requests from the control center, thereby significantly shortening the response latency of abnormal events.

[0090] For example, please refer to Figure 2 The distributed photovoltaic protocol converter has power quality monitoring, event logging, and active reporting of abnormal events. When the photovoltaic protocol converter detects events such as the photovoltaic inverter output voltage exceeding the limit or the smart switch tripping abnormally, it will immediately generate an abnormal reporting message, which will be sent to the concentrator via power line carrier or low-power wireless, and then forwarded by the concentrator to the power consumption information collection system via the public wireless network.

[0091] Please see Figure 3The distributed energy storage protocol converter has event logging, data analysis, and proactive reporting functions. When the energy storage protocol converter collects alarm information such as excessively high battery temperature or abnormal charging / discharging power through the energy storage converter, it proactively reports to the electricity consumption information collection system so that the control center can adjust the charging / discharging strategy of the energy storage unit or take protective measures in a timely manner.

[0092] By enabling the protocol conversion device to store local data and proactively report abnormal events, some monitoring and judgment functions can be moved to the edge, reducing reliance on periodic polling at the control center, improving the real-time response to abnormal events, and reducing uplink communication link bandwidth usage.

[0093] In some embodiments, the device-side communication protocol for the photovoltaic unit and / or the energy storage unit is the Modbus-RTU protocol. The device-side communication protocol for the charging pile unit is the CAN protocol. The unified communication protocol is the DL / T698.45 protocol.

[0094] In this embodiment, the Modbus-RTU protocol is a serial communication protocol based on a master-slave architecture, employing binary encoding and cyclic redundancy check. It is widely used in field device data acquisition and control in industrial automation. Specifically, in distributed photovoltaic power generation and energy storage applications, mainstream photovoltaic inverters and energy storage converters typically come standard with RS485 communication interfaces and are compatible with the Modbus-RTU protocol as their external data exchange communication protocol. Therefore, selecting or configuring the Modbus-RTU protocol as the device-side communication protocol for photovoltaic units and / or energy storage units enables plug-and-play communication compatibility with the vast majority of photovoltaic inverters and energy storage converters on the market, without requiring hardware modifications or protocol customization of the terminal equipment.

[0095] The CAN protocol is a serial bus protocol that supports multi-master communication. It employs differential signal transmission and bit-by-bit arbitration, offering strong resistance to electromagnetic interference and real-time performance. It is widely used in automotive electronics and electric vehicle charging. Specifically, in electric vehicle charging pile applications, data exchange between the charging pile and the vehicle's battery management system, as well as between various control modules within the charging pile, typically uses the CAN protocol. Therefore, selecting or configuring the CAN protocol as the device-side communication protocol for the charging pile unit aligns with the technical standards and application practices of the charging pile industry.

[0096] The DL / T698.45 protocol is an object-oriented communication protocol standard for the power industry, used for data exchange between concentrators and the master station, and between concentrators and acquisition terminals in electricity consumption information acquisition systems. Specifically, the DL / T698.45 protocol adopts an object-oriented data modeling approach, supports security mechanisms such as data encryption and authentication, and can meet the requirements of power systems for data acquisition, equipment control, and information security management. By selecting the DL / T698.45 protocol as the unified communication protocol, data interaction between the protocol conversion layer and the data transmission layer, and between the data transmission layer and the control center layer, can utilize standard communication protocols widely deployed in the power industry. This allows the system to directly integrate with the existing electricity consumption information acquisition system architecture without requiring additional modifications to the master station system.

[0097] Under the above protocol selection, the protocol conversion functions of each protocol conversion device in the protocol conversion layer are specified. Please refer to [link / reference]. Figure 2 The distributed photovoltaic protocol converter communicates with the photovoltaic inverter via RS485, is compatible with the Modbus-RTU protocol, and performs bidirectional conversion between the Modbus-RTU protocol and the DL / T698.45 protocol. Please refer to [link / reference]. Figure 3 The distributed energy storage protocol converter communicates with the energy storage converter via RS485 or Ethernet, is compatible with the Modbus-RTU protocol of mainstream energy storage converter manufacturers, and performs bidirectional conversion between the Modbus-RTU protocol and the DL / T698.45 protocol. Please refer to [link / reference]. Figure 4 The intelligent monitoring terminal for charging piles communicates with the charging piles via a CAN bus, is compatible with the CAN protocol, and performs bidirectional conversion between the CAN protocol and the DL / T698.45 protocol.

[0098] For example, the photovoltaic inverter sends power generation and voltage data to a distributed photovoltaic protocol converter via the Modbus-RTU protocol. The converter converts this data to the DL / T698.45 protocol, encrypts it, and then uploads it. The energy storage converter sends remaining power and charge / discharge status data to a distributed energy storage protocol converter via the Modbus-RTU protocol. The converter converts this data to the DL / T698.45 protocol, encrypts it, and then uploads it. The charging pile sends charging power and battery SOC data to the charging pile intelligent monitoring terminal via the CAN protocol. The terminal converts this data to the DL / T698.45 protocol, encrypts it, and then uploads it. In the command sending direction, the DL / T698.45 protocol control commands issued by the control center are converted into corresponding Modbus-RTU protocol commands or CAN protocol commands by each protocol conversion device, thereby controlling the operation of the corresponding units.

[0099] By selecting Modbus-RTU as the device-side communication protocol for photovoltaic units and / or energy storage units, CAN as the device-side communication protocol for charging pile units, and DL / T698.45 as the unified communication protocol, the system can be maximally compatible with the mainstream distributed photovoltaic, energy storage, and charging pile equipment already deployed in the existing distribution area. This enables interconnection and coordinated control between heterogeneous devices with relatively low retrofit costs, thereby improving the system's versatility and engineering feasibility.

[0100] In some embodiments, please refer to Figure 4 The protocol conversion device corresponding to the charging pile unit communicates with the charging pile in the charging pile unit via a CAN bus with a resistor in series in a differential signal manner.

[0101] In this embodiment, the CAN bus is the physical communication link connecting the protocol conversion device and the charging pile. Specifically, the CAN bus uses twisted-pair cable as the transmission medium and transmits digital signals through the voltage difference between the two signal lines, i.e., differential signaling. Differential signaling refers to a transmission method that uses the voltage difference between two signal lines to represent logic levels. When the CAN bus transmits signals, the two signal lines carry oppositely phased level signals, and the receiving end identifies the transmitted logic state by detecting the differential voltage between the two signal lines. Compared with single-ended signal transmission, differential signaling can effectively suppress common-mode interference, exhibiting stronger anti-interference capabilities and higher communication reliability in complex electromagnetic environments such as distribution networks.

[0102] In the physical layer connection of the CAN bus, a resistor is connected in series on the CAN bus between the protocol conversion device and the charging pile. Specifically, this series resistor can be set at the end of the CAN bus as a termination matching resistor. The termination matching resistor is used to match the characteristic impedance of the CAN bus, suppressing signal reflection at the end of the bus, thereby ensuring the transmission quality of differential signals on the bus. For example, the resistance value of this series resistor can be 2.1KΩ. This resistance value is selected based on the termination matching resistor value recommended in the CAN bus standard physical layer specification, combined with the actual electrical characteristics of the charging pile's CAN communication interface.

[0103] Please see Figure 4 The intelligent monitoring terminal for charging piles (i.e., the protocol conversion device corresponding to each charging pile unit) connects to the charging piles via a CAN bus. A 2.1KΩ resistor is connected in series in the physical link of the CAN bus, and differential electrical signal transmission is used. The intelligent monitoring terminal interacts with each charging pile through this CAN bus, collecting operational data such as charging power and charging status, and sending control commands for charging power and charging time to the charging piles.

[0104] By employing a CAN bus with a series resistor and communicating using differential signals, the stability and reliability of communication between the protocol conversion device and the charging pile in the complex electromagnetic environment of the distribution area can be guaranteed, ensuring the accurate delivery of control commands and the complete acquisition of operating data.

[0105] In some embodiments, please refer to Figure 1 The data transmission layer includes a concentrator. The concentrator communicates with the protocol conversion layer via power line carrier or low-power wireless, and with the control center layer via a public wireless network.

[0106] In this embodiment, the concentrator is a communication aggregation device deployed on the local side of the distribution area. It is used to collect data reported by various protocol conversion devices in the protocol conversion layer and to interact with the control center layer via remote communication. Specifically, the concentrator performs the function of transparent data forwarding, encapsulating the operating data from the protocol conversion layer and forwarding it to the control center layer, as well as forwarding the control commands from the control center layer to the corresponding protocol conversion devices.

[0107] The concentrator communicates with the protocol conversion layer using either power line carrier (PLC) or low-power wireless. PLC is a technology that uses existing power lines as the transmission medium for data communication. Specifically, PLC transmits high-frequency data signals by coupling them onto power lines. Since power lines already cover all equipment nodes within the distribution area, PLC eliminates the need for additional engineering and cost associated with laying communication cables. Low-power wireless is a wireless communication technology that uses low transmission power. Specifically, low-power wireless transmits data over short distances using radio frequency signals, offering advantages such as flexible deployment, no wiring required, and easy installation. The concentrator can choose one or both PLC or low-power wireless technologies for a hybrid network, depending on factors such as power line quality, electromagnetic environment conditions, and equipment distribution within the distribution area, to achieve reliable communication coverage with the protocol conversion devices in the protocol conversion layer.

[0108] The concentrator communicates with the control center via a public wireless network. This public wireless network is a public mobile communication network deployed by the operator. Specifically, it can be a wide-area wireless communication network such as fourth-generation (4G) or fifth-generation (5G). Through this network, the concentrator can remotely transmit local operating data from the distribution area to a remote electricity consumption information collection system and receive control commands from that system. Compared to wired private networks, using a public wireless network for remote communication significantly reduces the construction and maintenance costs of communication infrastructure, making it suitable for scenarios with a large number of distributed distribution areas and a wide geographical distribution.

[0109] For example, a distribution area concentrator is installed in the data transmission layer. This concentrator supports power line carrier, low-power wireless, and public wireless network communication. In the protocol conversion layer, the distributed photovoltaic protocol converter communicates with the concentrator via power line carrier, the distributed energy storage protocol converter communicates with the concentrator via low-power wireless, and the charging pile intelligent monitoring terminal communicates with the concentrator via power line carrier. The concentrator forwards data from each protocol conversion device to the electricity consumption information collection system via the public wireless network, and forwards the control commands issued by the electricity consumption information collection system to each protocol conversion device through the corresponding local communication method.

[0110] A hybrid communication architecture that uses a concentrator for local communication aggregation via power line carrier or low-power wireless and for remote data backhaul via public wireless network can balance the convenient deployment of local communication in the transformer area with the wide-area coverage requirements of remote communication, reducing the construction cost of the communication system while ensuring the reliability and real-time performance of data transmission.

[0111] In some embodiments, please refer to Figure 4 The protocol conversion device corresponding to the charging pile unit has a built-in orderly charging control strategy, which is used to regulate the charging time and charging power of each charging pile in the charging pile unit according to the control instructions issued by the control center.

[0112] In this embodiment, the ordered charging control strategy is a localized charging management and control logic deployed within the protocol conversion device corresponding to the charging pile unit. Specifically, within the overall control target or power constraint range issued by the control center, the ordered charging control strategy performs refined timing arrangement and power allocation of the charging behavior of each charging pile in the charging pile unit according to the real-time status of each charging pile and the user's charging needs. The ordered charging control strategy is in contrast to the conventional charging method of plug-and-charge without coordination mechanism. Its core lies in achieving orderly management of the charging load of multiple charging piles and optimized utilization of the area resources through peak-shaving scheduling in the time dimension and flexible adjustment in the power dimension.

[0113] The protocol conversion device corresponding to the charging pile unit can specifically be a charging pile intelligent monitoring terminal. The charging pile intelligent monitoring terminal has a built-in orderly charging control strategy, which not only enables it to perform bidirectional protocol conversion, but also endows it with the decision-making ability for edge-side charging management.

[0114] The input information for the orderly charging control strategy includes control commands issued by the control center and charging pile status data collected locally by the protocol conversion device. Specifically, the control commands issued by the control center may include the total charging power limit or target value of the charging pile units within the current scheduling period of the distribution area. This command is calculated by the control center based on global information such as the remaining capacity of the distribution area transformer, photovoltaic output prediction, time-of-use pricing, and energy storage status, through a collaborative control model. The charging pile status data collected locally by the protocol conversion device may include information such as the real-time charging power, charging energy, electric vehicle battery state of charge, and user charging preference settings for each charging pile.

[0115] The orderly charging control strategy is used to regulate the charging time and charging power of each charging pile in the charging pile unit according to the control instructions issued by the control center. Specifically, after receiving the control instructions from the control center, the orderly charging control strategy uses the overall control target in the instructions as boundary conditions and combines it with the local state information of each charging pile to generate independent charging control decisions for each charging pile. Regulation of charging time refers to scheduling the charging start time, charging end time, or charging period for each charging pile. For example, some delayable charging demands are scheduled to be executed during peak photovoltaic output periods or off-peak periods when grid electricity prices are low, while non-delayable emergency charging demands are scheduled to be executed during the currently available time period. Regulation of charging power refers to dynamically adjusting the output power of each charging pile. For example, when there is sufficient remaining capacity in the distribution area, the charging power of each charging pile is appropriately increased; when the remaining capacity in the distribution area is insufficient, the charging power of each charging pile is reduced according to priority or proportion, ensuring that the total charging power of all charging piles does not exceed the upper limit of available charging power issued by the control center.

[0116] In the aforementioned control process, the orderly charging control strategy performs a fine-grained decomposition function at the edge. The control commands issued by the control center are directed at the entire charging pile unit, providing aggregated power targets or limits. The orderly charging control strategy decomposes this aggregated target into independent control commands for each charging pile, achieving a control closed loop from "area-level collaborative decision-making" to "equipment-level fine-grained execution".

[0117] For example, after analyzing the remaining capacity of the power distribution area and the photovoltaic output forecast, the electricity information collection system generates a control command, requiring the charging piles to adjust their total charging power to 60kW. Upon receiving this command, the charging pile intelligent monitoring terminal uses its built-in orderly charging control strategy to determine the charging time and power allocation scheme for each of the 10 connected charging piles based on their respective charging status, electric vehicle battery SOC, and user demand. This adjusts the total charging power of the 10 charging piles to 60kW and rationally distributes power among them. Finally, it converts the power into independent control commands for each charging pile using the CAN protocol and sends them to the corresponding charging piles for execution.

[0118] By deploying the orderly charging control strategy in the protocol conversion device corresponding to the charging pile unit, edge-side intelligent decision-making for charging pile regulation can be realized, reducing the computational burden and communication overhead of the control center layer in generating detailed control instructions for each charging pile. At the same time, even if the communication between the control center layer and the protocol conversion device is interrupted for a short time, the orderly operation of each charging pile can still be maintained based on the most recently received control instructions and local information, thus improving the robustness and real-time response of the system.

[0119] Please see Figure 5 Another embodiment of the present invention provides a method for coordinated control of optical storage and charging based on communication protocol conversion, which is applied to the optical storage and charging coordinated control system based on communication protocol conversion in any of the above embodiments. The method may include the following steps.

[0120] Step S210: Collect the operating data of the photovoltaic unit, energy storage unit and charging pile unit in the equipment terminal layer respectively, convert the operating data of each unit from its equipment side communication protocol to a unified communication protocol, and upload it to the control center layer.

[0121] Specifically, the operational data of each unit in the equipment terminal layer is collected by the corresponding connected protocol conversion device. For photovoltaic units, the protocol conversion device collects operational data such as power generation, output voltage, and output current of the photovoltaic inverter through the downlink communication interface. For energy storage units, the protocol conversion device collects operational data such as remaining power, charging and discharging power, voltage, current, and temperature of the energy storage converter through the downlink communication interface. For charging pile units, the protocol conversion device collects operational data such as charging power, charging energy, and charging status of the charging pile through the downlink communication interface. Simultaneously, the transformer area monitoring equipment collects data on the transformer capacity, remaining capacity, load rate, and voltage and current data of each node in the transformer area.

[0122] After completing the operational data acquisition, each protocol conversion device converts the collected operational data from its original equipment-side communication protocol to a unified communication protocol. Specifically, the distributed photovoltaic protocol converter converts the Modbus-RTU protocol data of the photovoltaic inverter to DL / T698.45 protocol data, the distributed energy storage protocol converter converts the Modbus-RTU protocol data of the energy storage converter to DL / T698.45 protocol data, and the charging pile intelligent monitoring terminal converts the CAN protocol data of the charging pile to DL / T698.45 protocol data. The converted unified communication protocol data is encrypted and then transmitted to the concentrator via power line carrier or low-power wireless transmission. The concentrator then uploads the data to the control center via the public wireless network.

[0123] Step S220: The control center layer generates control commands using a unified communication protocol, which are used to control the photovoltaic unit, energy storage unit and charging pile unit respectively, based on the respective operating data of the photovoltaic unit, energy storage unit and charging pile unit, and sends them to the data transmission layer.

[0124] Specifically, the control center layer decrypts and analyzes the uploaded operational data, combines weather and temperature information to predict the power generation output of distributed photovoltaic systems, analyzes the remaining capacity and load rate of transformers in the distribution area, and integrates time-of-use pricing and information on voltage and current at each node. With the goal of minimizing operating costs and maximizing emission reduction benefits, the control center layer establishes constraints and triggering mechanisms, and generates control commands for each unit through a collaborative control model. These control commands are encapsulated using a unified communication protocol, encrypted, and then sent to the concentrator in the data transmission layer.

[0125] Step S230: The data transmission layer forwards the control command to the protocol conversion device corresponding to the device terminal layer.

[0126] Specifically, after receiving the encrypted control command from the control center layer, the concentrator transparently forwards the control command to the corresponding protocol conversion device via power line carrier or low-power wireless, based on the target device identification information carried in the control command. During this process, the concentrator does not parse the command content; it only performs data forwarding at the communication link layer.

[0127] Step S240: The protocol conversion device converts the communication protocol of the control command from the unified communication protocol to the device-side communication protocol of the corresponding unit in order to control the operation of the corresponding unit.

[0128] Specifically, after receiving the encrypted control command, the protocol conversion device first decrypts the encrypted message using its built-in security module, recovering the plaintext control command using the unified communication protocol. Then, the protocol conversion device converts the decrypted control command from the unified communication protocol to the device-side communication protocol compatible with the corresponding unit. Specifically, the distributed photovoltaic protocol converter converts DL / T698.45 protocol commands to Modbus-RTU protocol commands to control the photovoltaic inverter for flexible power regulation or directly control the smart switch to perform rigid opening and closing operations. The distributed energy storage protocol converter converts DL / T698.45 protocol commands to Modbus-RTU protocol commands to control the charging and discharging operation mode and charging and discharging power of the energy storage converter. The charging pile intelligent monitoring terminal converts DL / T698.45 protocol commands to CAN protocol commands to control the charging time and charging power of each charging pile.

[0129] Following S240, the method further includes steps of status feedback and closed-loop optimization. Specifically, after executing the control command, each unit feeds back the control execution result to the control center layer via the protocol conversion layer and data transmission layer. The control center layer monitors the operating status of each node in the distribution area and the execution status of the control commands by each unit in the equipment terminal layer in real time. If the actual execution result deviates from the control target, or if the operating status of the distribution area changes, the subsequent control commands are dynamically corrected and adjusted, forming a closed-loop control process of data acquisition, command generation, command issuance, equipment execution, and status feedback.

[0130] For example, after analyzing the remaining capacity of the distribution area and the photovoltaic output forecast, the electricity consumption information acquisition system generates control commands, requiring the photovoltaic inverters to maintain output, the energy storage converters to charge at a specified power, and the charging piles to adjust their total charging power to the target value. These control commands are forwarded to each protocol conversion device via a concentrator. Each protocol conversion device converts the DL / T698.45 protocol commands into corresponding equipment-side protocol commands and then controls each unit to execute them. After execution, each unit feeds back the execution results to the electricity consumption information acquisition system through the original communication path.

[0131] Using the above method, unified collection and protocol conversion of distributed photovoltaic, energy storage and charging pile operation data can be achieved within a single distribution area. The control center generates coordinated control commands based on global information, which are then converted in reverse by the protocol conversion layer to control each unit. This breaks down communication barriers between heterogeneous protocol devices, achieves coordinated control of photovoltaic, energy storage and charging and self-balancing of the distribution area, reduces line loss in the distribution area and improves grid stability.

[0132] In some embodiments, in step S220, the control center layer generates control commands that use a unified communication protocol and are used to control the photovoltaic unit, energy storage unit, and charging pile unit respectively, based on the respective operating data of the photovoltaic unit, energy storage unit, and charging pile unit. This may include the following steps.

[0133] Step S221: Based on the grid purchase cost, energy storage cycle loss cost, and grid loss cost, construct a comprehensive operating cost function within the scheduling cycle.

[0134] Step S222: Based on the predicted power generation of the photovoltaic unit, the photovoltaic grid-connected redundant power, and the photovoltaic carbon emission reduction coefficient during the scheduling period, construct the emission reduction benefit function during the scheduling period.

[0135] Step S223: Construct a comprehensive objective function based on the comprehensive operating cost function and the emission reduction benefit function.

[0136] Step S224: With the goal of minimizing the comprehensive objective function and the constraint set of the transformer substation as the constraint condition, generate control commands for the photovoltaic unit, the energy storage unit, and the charging pile unit.

[0137] In this embodiment, the process of generating control commands at the control center layer relies on the collaborative control model. The collaborative control model is the core algorithm model used by the control center layer to generate control commands for each unit. Based on the global operating data of the distribution area, the collaborative control model, while satisfying the safety constraints and operating characteristics of the power grid equipment, takes into account both economic and environmental control objectives, and obtains the real-time control power commands for each unit through multi-objective optimization.

[0138] The comprehensive operating cost function is a mathematical expression used to quantify the economic cost of operating a distribution area within a scheduling cycle. The scheduling cycle is the time range within which the coordinated control model performs optimization calculations, and can be divided into multiple scheduling periods. Specifically, the comprehensive operating cost function includes three components: grid power purchase cost, energy storage cycle loss cost, and grid loss cost.

[0139] The grid purchase cost represents the fee paid by a distribution area to purchase electricity from the public grid. Specifically, the grid purchase cost can be determined based on the power exchange between the distribution area and the public grid during each time period within the dispatch cycle and the corresponding time-of-use (TOU) price. Under the TOU pricing mechanism, the grid purchase cost is higher during peak electricity price periods and lower during off-peak electricity price periods. By incorporating the grid purchase cost into the comprehensive operating cost function, the coordinated control model can be guided to restrict electricity purchases and prioritize the use of local photovoltaic and energy storage resources during peak electricity price periods, and encourage energy storage charging during off-peak electricity price periods, thereby reducing the overall electricity cost for the distribution area.

[0140] Energy storage cycle loss cost characterizes the lifespan degradation cost of energy storage batteries due to cyclic use during charging and discharging. Specifically, the energy storage cycle loss cost can be determined based on the difference between the charging power and discharging power of the energy storage battery within a scheduling cycle and a unit energy storage cycle loss cost coefficient. The cycle life of an energy storage battery is closely related to its charge / discharge depth and charge / discharge rate; frequent high-power charge / discharge cycles accelerate the capacity degradation of the energy storage battery. By incorporating the energy storage cycle loss cost into the comprehensive operating cost function, the coordinated control model can be guided to avoid frequent deep high-power charge / discharge cycles of the energy storage battery, thereby extending its lifespan.

[0141] Network loss cost characterizes the energy loss cost incurred by transformers and distribution lines in a distribution area during active power transmission. Specifically, network loss cost can be determined based on the active power loss of the distribution area within the dispatch cycle and the unit network loss cost coefficient. The active power loss of a distribution area is closely related to the power distribution of each node. By optimizing the power allocation of photovoltaic, energy storage, and charging piles, and improving the power flow distribution, the line loss of the distribution area can be reduced. By including network loss cost in the comprehensive operating cost function, the collaborative control model can be guided to consider the impact of power allocation on the line loss of the distribution area when generating control instructions, thereby achieving loss reduction and energy saving.

[0142] For example, the comprehensive operating cost function can be expressed by the following formula:

[0143]

[0144] in, The total operating cost within the scheduling cycle, This represents the number of scheduling periods included in the scheduling cycle. For the first The interaction power between the distribution area and the public power grid during the time period. For the first Electricity price during the specified time period and The first The charging and discharging power of the time-limited energy storage battery. For the first Unit energy storage cycle loss cost coefficient for a given period of time. For the first Active power loss during a given period For the first Unit network loss cost coefficient for a given time period.

[0145] The emission reduction benefit function is a mathematical expression used to quantify the carbon emission reduction benefits obtained by a distribution area from the local consumption of distributed photovoltaic power generation within a dispatch cycle. Specifically, the emission reduction benefit function is determined based on the predicted power generation of the photovoltaic units within the dispatch cycle, the redundant power of photovoltaic grid connection, and the photovoltaic carbon emission reduction coefficient.

[0146] The predicted power generation of a photovoltaic (PV) unit is an estimated value of the PV array's output power for each period within the dispatch cycle, based on factors such as weather, temperature, and sunlight conditions. PV grid-connected redundant power refers to the portion of the PV unit's power generation that is not absorbed by local loads, energy storage charging, or charging piles, and needs to be fed back to the public grid. The PV carbon emission reduction coefficient is the carbon emission reduction corresponding to a unit of PV power generation, used to convert local PV consumption into carbon emission reduction benefits.

[0147] The core objective of the emission reduction benefit function is to maximize the local consumption of photovoltaic (PV) power and minimize the redundant power fed into the grid. By charging and storing surplus energy in batteries during peak PV output periods and arranging electric vehicle charging at charging stations during these periods to consume surplus energy, the backflow of PV power into the public grid can be reduced, increasing the local consumption ratio of PV power and thus improving carbon emission reduction efficiency.

[0148] For example, the emission reduction benefit function can be expressed by the following formula:

[0149]

[0150] in, For the emission reduction benefits during the scheduling cycle, For the first Predicted power generation of photovoltaic units during the time period For the first Redundant power of photovoltaic grid connection during a given period This represents the carbon emission reduction coefficient for photovoltaic systems. and The difference is the number The local consumption capacity of photovoltaic power generation during a given period.

[0151] The comprehensive objective function is a unified mathematical expression constructed based on the comprehensive operating cost function and the emission reduction benefit function, used for the coordinated optimization of economic and environmental aspects. Since the comprehensive operating cost function and the emission reduction benefit function have inconsistent dimensions and opposite optimization directions—that is, minimizing costs and maximizing emission reduction benefits—the coordinated control model adopts a multi-objective weighted normalization fusion strategy to transform the two objective functions into a single comprehensive objective function for unified solution.

[0152] Specifically, the coordinated control model first performs range standardization on the comprehensive operating cost function and the emission reduction benefit function to eliminate dimensional differences. Range standardization normalizes the values ​​of each objective function to a uniform numerical range, making objective functions with different dimensions comparable. Then, the coordinated control model introduces weighting coefficients to weightedly combine the two standardized objective functions into a single comprehensive objective function. These weighting coefficients are used to adjust the relative importance between the operating cost target and the emission reduction benefit target.

[0153] For example, the comprehensive objective function can be expressed by the following formula:

[0154]

[0155] in, For the comprehensive objective function, and Let be the weighting coefficient, satisfying ; and These represent the minimum and maximum possible values ​​of the comprehensive operating cost function within the scheduling period, respectively. and These represent the minimum and maximum possible values ​​of the emission reduction benefit function within the scheduling period, respectively. The negative sign before the second term in the formula is used to unify the maximization of emission reduction benefits into the minimization solution direction, achieving simultaneous optimization that minimizes operating costs and maximizes emission reduction benefits.

[0156] Weighting coefficient and It can be dynamically adjusted according to the actual operating conditions of the transformer substation. Specifically, under normal operating conditions, and Both can be set to 0.5 to balance economic and environmental goals. During periods of heavy grid load, the value can be increased. The value of this parameter allows the coordinated control model to focus more on reducing operating costs and ensuring grid security. During periods of high renewable energy generation, the parameter can be increased. The value of makes the collaborative regulation model focus more on improving photovoltaic absorption rate and carbon emission reduction benefits.

[0157] After constructing the comprehensive objective function, the collaborative control model optimizes the solution with the goal of minimizing the comprehensive objective function. During the solution process, the collaborative control model uses the constraint set of the transformer substations as constraints. The constraint set is a set of boundary conditions that ensure the optimization results satisfy the safety and operational characteristics of the power grid equipment.

[0158] Specifically, the constraint set may include at least one of the following: distribution area power balance constraints, transformer operation constraints, energy storage device operation constraints, charging pile operation and user constraints, and grid power quality constraints. Distribution area power balance constraints ensure that the power output and load consumption within the distribution area meet a power balance relationship during any dispatching period. Transformer operation constraints ensure that the load rate of the transformers in the distribution area does not exceed the allowable range of their rated capacity, and that the voltage at each node of the transformer does not exceed the limit. Energy storage device operation constraints ensure that the remaining capacity of the energy storage batteries is maintained within a safe operating range, and that the charging and discharging power does not exceed the rated power limit of the energy storage converter. Charging pile operation and user constraints ensure that the total charging power of the charging piles does not exceed the upper limit of the available charging power, and meets the charging needs and preferences set by users. Grid power quality constraints ensure that power quality indicators such as voltage deviation, frequency deviation, and harmonic content at each node of the distribution area meet the relevant standard requirements.

[0159] Under the constraints set described above, the collaborative control model solves for the minimum of the comprehensive objective function to obtain the control power commands for photovoltaic (PV) units, energy storage units, and charging pile units at each time period within the scheduling cycle. Specifically, for PV units, the control commands may include the output power target value or power limit of the PV inverter, and may also include the switching commands of smart switches if necessary, to achieve flexible control or rigid control of the PV units. For energy storage units, the control commands may include the charging and discharging operation mode and charging and discharging power target value of the energy storage converter. For charging pile units, the control commands may include the total charging power limit or target value of the charging pile unit, which is further decomposed into the charging time and charging power of each charging pile by the orderly charging control strategy built into the intelligent monitoring terminal of the charging pile.

[0160] By incorporating photovoltaic (PV) units into the optimized output range of the collaborative control model, the control center can directly adjust the output of PV units. Specifically, when the PV output of a distribution area exceeds the local load absorption capacity, the energy storage is fully charged, and there is no charging demand from the charging piles, the collaborative control model can generate control commands to reduce the output power of the PV inverter, or disconnect part of the PV array through smart switches to avoid voltage over-limit problems caused by power feeding back into the public grid. When the load demand of a distribution area is high and the PV output is insufficient, the collaborative control model can generate control commands to increase the output of the PV inverter to the maximum power point tracking state, so as to make full use of PV power generation resources. Thus, the collaborative control model achieves unified and optimized scheduling of the power generation of PV units, the charging and discharging power of energy storage units, and the charging power of charging pile units.

[0161] The generated control commands are encapsulated using a unified communication protocol, encrypted, and then sent to the protocol conversion layer via the data transmission layer. Finally, each protocol conversion device converts the commands into the corresponding unit's device-side communication protocol to control the corresponding unit to execute them.

[0162] For example, the coordinated control model solves a comprehensive objective function under constraint sets based on input conditions such as the substation load rate, photovoltaic output, remaining energy storage capacity, and initial charging pile power. This generates control commands to maintain photovoltaic inverter output, charge the energy storage converter at a specified power, and adjust the total charging power of the charging piles to the target value. After control, all photovoltaic output is absorbed, the total load of the substation matches the power output, there is no backfeeding, and the substation achieves self-balancing. Before control, the substation line loss rate was 3.2%, which decreased to 2.1% after control, a reduction of 1.1 percentage points. Before control, the low-voltage side voltage fluctuation range was ±3.5%, which was reduced to ±1.8% after control, meeting power quality standards.

[0163] By constructing a multi-objective optimization model that minimizes operating costs and maximizes emission reduction benefits, and employing a normalized weighted fusion strategy for unified solution, and using the constraint set of the transformer substation as the constraint condition, control commands are generated for the photovoltaic unit, energy storage unit, and charging pile unit. This approach can simultaneously consider economic and environmental control objectives while ensuring the safe operation of the substation, achieving coordinated and optimized scheduling of photovoltaic power generation, energy storage charging and discharging, and charging pile charging. This avoids the severe curtailment problem caused by single cost optimization and the excessively high operating costs caused by single emission reduction optimization, achieving a dual optimization of economic efficiency and environmental protection.

[0164] In this invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating the relative importance of the indicated features or the number of indicated technical features. Therefore, a feature defined as "first" or "second" can explicitly include at least one of that feature. In this application, "a plurality of" means at least two, such as two, three, etc.; "several" means at least one, such as one, two, three, etc., unless otherwise explicitly specified.

[0165] In this invention, unless otherwise explicitly defined, the terms "installation," "connection," "linking," "fixing," and "setting," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral part; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can also refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0166] It should be understood that the above embodiments are exemplary and are not intended to encompass all possible implementations included in the claims. Various modifications and changes can be made to the above embodiments without departing from the scope of this disclosure. Similarly, the various technical features of the above embodiments can be arbitrarily combined to form other embodiments of this application that may not be explicitly described. Therefore, the above embodiments only illustrate several implementations of this application and do not limit the scope of protection of this patent application.

Claims

1. A photoelectric storage-charging coordinated control system based on communication protocol conversion, characterized in that, include: The equipment terminal layer includes a photovoltaic unit, an energy storage unit, and a charging pile unit. The three units communicate with the outside world according to their respective equipment-side communication protocols; among them, at least two of the three units have different equipment-side communication protocols. The protocol conversion layer includes a protocol conversion device connected to each unit of the device terminal layer, which converts the operating data of the corresponding unit from the device-side communication protocol to the unified communication protocol and then sends it to the data transmission layer; and converts the communication protocol of the control command from the unified communication protocol to the device-side communication protocol of the corresponding unit. The data transmission layer is communicatively connected to both the protocol conversion layer and the control center layer, and is used to forward operating data and control commands using the unified communication protocol between the protocol conversion layer and the control center layer. The control center layer is used to receive the operating data of the device terminal layer; and to generate control instructions for each unit of the device terminal layer based on the operating data, and send them to the protocol conversion layer through the data transmission layer.

2. The photoelectric storage-charging coordinated control system based on communication protocol conversion according to claim 1, characterized in that, Each of the aforementioned protocol conversion devices has a built-in security module; The control center layer is used to encrypt the control commands and then send them through the data transmission layer. The protocol conversion device is used to decrypt the received encrypted control commands and then convert them from the unified communication protocol into the device-side communication protocol of the corresponding unit.

3. The photoelectric storage-charging coordinated control system based on communication protocol conversion according to claim 1, characterized in that, Also includes: Monitoring equipment for transformer substations; The transformer area monitoring equipment is used to collect at least one of the following: transformer capacity, remaining capacity, load rate, and voltage and current data of transformer nodes in the transformer area; and uploads the collected data to the control center layer via the data transmission layer. The control center layer is also used to determine the upper limit of the available charging power of the charging pile unit based on the remaining capacity of the transformer in the distribution area, and to ensure that the limit on the charging power of the charging pile unit in the generated control command does not exceed the upper limit of the available charging power.

4. The photoelectric storage-charging coordinated control system based on communication protocol conversion according to claim 1, characterized in that, Each of the protocol conversion devices is also used to collect and store the operating data of the corresponding unit, and to report to the control center layer when an abnormal event is detected.

5. The photoelectric storage-charging coordinated control system based on communication protocol conversion according to claim 1, characterized in that, The device-side communication protocol of the photovoltaic unit and / or the device-side communication protocol of the energy storage unit is the Modbus-RTU protocol; The device-side communication protocol of the charging pile unit is the CAN protocol; The unified communication protocol is DL / T698.

45.

6. The photoelectric storage-charging coordinated control system based on communication protocol conversion according to claim 5, characterized in that, The protocol conversion device corresponding to the charging pile unit communicates with the charging pile in the charging pile unit via a CAN bus with a resistor in series in a differential signal manner.

7. The photoelectric storage-charging coordinated control system based on communication protocol conversion according to claim 1, characterized in that, The data transmission layer includes a concentrator; The concentrator communicates with the protocol conversion layer via power line carrier or low-power wireless, and communicates with the control center layer via a public wireless network.

8. The photoelectric storage-charging coordinated control system based on communication protocol conversion according to claim 1, characterized in that, The protocol conversion device corresponding to the charging pile unit has a built-in orderly charging control strategy, which is used to regulate the charging time and charging power of each charging pile in the charging pile unit according to the control instructions issued by the control center layer.

9. A method for coordinated control of optical storage and charging based on communication protocol conversion, characterized in that, The method is applied to the optical-storage-charging coordinated control system based on communication protocol conversion as described in any one of claims 1 to 8, and the method includes: The system collects the operating data of the photovoltaic unit, energy storage unit, and charging pile unit in the equipment terminal layer, converts the operating data of each unit from its equipment-side communication protocol to a unified communication protocol, and uploads it to the control center layer. The control center layer generates control commands using a unified communication protocol, which are used to control the photovoltaic unit, energy storage unit, and charging pile unit respectively, based on the respective operating data of the photovoltaic unit, energy storage unit, and charging pile unit, and sends them down to the data transmission layer. The data transmission layer forwards control commands to the protocol conversion device corresponding to the device terminal layer. The protocol conversion device converts the communication protocol of the control command from the unified communication protocol to the device-side communication protocol of the corresponding unit in order to control the operation of the corresponding unit.

10. The method according to claim 9, characterized in that, The control center layer generates control commands, using a unified communication protocol, for controlling the photovoltaic unit, energy storage unit, and charging pile unit respectively, based on the respective operating data of the photovoltaic unit, energy storage unit, and charging pile unit. These commands include: Based on the grid purchase cost, energy storage cycle loss cost, and grid loss cost, a comprehensive operating cost function is constructed within the scheduling cycle. Based on the predicted power generation of the photovoltaic unit, the redundant power of the photovoltaic grid connection and the photovoltaic carbon emission reduction coefficient during the scheduling period, an emission reduction benefit function is constructed for the scheduling period. A comprehensive objective function is constructed based on the comprehensive operating cost function and the emission reduction benefit function. With the goal of minimizing the comprehensive objective function and the constraint set of the transformer substation as the constraint condition, control commands for the photovoltaic unit, the energy storage unit, and the charging pile unit are generated.

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