What is CAN Communication Protocol in Energy Storage System
Description
CAN communication protocol in energy storage systems is a protocol used to achieve reliable and efficient communication among various devices in the energy storage system,the meaning is Controller Area Network.
1.Characteristics
1.1 High reliability
CAN communication protocol equipped with a complete error detection and handling mechanism, such as cyclic Redundancy Check (CRC), etc., which can promptly identify and correct errors in data transmission to ensure the accuracy of the data.
1.2 Strong real-time
The adoption of a priority arbitration mechanism can ensure that important data is transmitted first, meeting the real-time requirements of energy storage systems,for instance, key information such as battery status data can be conveyed promptly.
1.3 Multi-master station structure
CAN communication protocol allowing multiple devices in the energy storage system to simultaneously act as the master station to send data, with each device having an equal status, can be flexibly configured as needed, enhancing the flexibility and scalability of the system.
1.4 Strong anti-interference ability
Differential signal transmission is adopted, which can effectively suppress electromagnetic interference and operate stably in complex electromagnetic environments, ensuring the stability of communication.
2.Working principle
2.1 Data frame format
The data frame is the basic unit for transmitting data in CAN communication protocol, including parts such as the frame start, arbitration field, control field, data field, CRC field, response field and frame end.
The arbitration field determines the priority of data frames, the control field contains information such as data length, and the data field stores the actual data to be transmitted, such as parameters like battery voltage and current.
2.2 Signal transmission
CAN communication protocol are transmitted through two signal lines, CAN_H and CAN_L, and the logical state is represented by the voltage difference between them.
In the dominant state, the voltage of CAN_H is higher than that of CAN_L. In the recessive state, the voltage difference between the two is 0V. This differential signal transmission mode enhances the anti-interference ability of the signal.
2.3 Communication process
When the device has data to send, it will first encapsulate the data in the prescribed frame format and then send it to the bus.
Other devices on the bus will listen for the data frame and determine whether it is the data they need to receive based on the identifier in the frame. If it is, they will process it accordingly; if not, they will ignore it.
3.Application scenarios
3.1 Internal communication of the Battery Management System (BMS)
CAN communication protocol is used to connect the main control unit in the BMS with each battery module monitoring unit, to achieve functions such as status monitoring and balanced management of the battery pack, ensuring the safe and efficient operation of the battery pack.
3.2 Communication between the energy storage converter (PCS) and the BMS
The PCS obtains the status information of the battery pack from the BMS through the CAN communication protocol, such as the state of charge (SOC) and health status (SOH), in order to reasonably control the charging and discharging process,meanwhile, the BMS can also receive the control instructions sent by the PCS to achieve precise control of the charging and discharging of the battery pack.
3.3 Communication between the energy management system (EMS) and energy storage devices
EMS communicates with each device in the energy storage system via CAN bus to achieve overall monitoring and dispatching of the energy storage system,according to the demand of the power grid and the status of energy storage devices, it rationally allocates charging and discharging tasks to optimize the operational efficiency of the energy storage system.
4.Conclusion
The CAN communication protocol in energy storage systems is an important communication protocol technology, which provides reliable and real-time communication connections for various devices in energy storage systems. Through specific data frame formats, signal transmission methods and communication processes, information interaction and collaborative work among devices have been achieved,it plays a key role in multiple links such as battery management, energy storage conversion and energy management, which helps to improve the performance, safety and reliability of energy storage systems and promotes the wide application of energy storage technology in power systems and other fields.