The energy storage system mainly consists of battery packs, battery management systems (BMS), energy management systems (EMS), energy storage inverters (PCS), and other electrical equipment. The BMS, EMS, and PCS are three key subsystems in the energy storage system, and they need to work together to achieve efficient operation of the energy storage system. Specifically,
Battery Management System BMS: plays a perception role, mainly responsible for monitoring, evaluating, protecting, and balancing batteries;
Energy Management System EMS: plays a decision-making role, mainly responsible for data collection, network monitoring, and energy scheduling;
Energy storage inverter PCS: plays an executive role, mainly responsible for controlling the charging and discharging process of the energy storage battery pack, and performing AC/DC conversion.
Here are their associations and ways of operation:
1. The correlation between BMS and PCS:
BMS ensures the safe and stable operation of the battery by monitoring and managing the status, battery level, temperature, and other information of the battery pack. PCS is responsible for controlling the power conversion of the energy storage system, converting stored energy into electricity that can be supplied or scheduled by the power grid. The BMS and PCS exchange data through a communication interface, where the BMS provides battery status information and control instructions to the PCS to regulate power output and charging and discharging processes, in order to protect the battery and ensure stable system operation.
Specific operation steps:
1) BMS monitors the battery status, such as battery level, temperature, etc;
2) BMS sends battery status information and control commands to PCS;
3) PCS adjusts power output or conducts charging and discharging processes based on BMS instructions;
4) PCS will provide real-time operational data feedback to BMS to ensure safe operation of the battery and system.

2. The correlation between EMS and PCS: EMS is mainly responsible for controlling the operation of the entire energy storage system, including scheduling, optimization, and power control operations. PCS is responsible for specific power conversion and electrical energy output, and controls the operation of the energy storage system according to EMS instructions. EMS controls and monitors the PCS through its communication interface, which is used to regulate the power output and operating mode of the energy storage system.

Specific operation steps:
1) EMS formulates operational strategies for energy storage systems by analyzing the load situation and demand of the power grid;
2) EMS sends operation control commands to PCS, including power output, charge and discharge control, etc;
3) PCS adjusts the power output and operating mode of the system based on EMS instructions;
4) PCS will provide real-time operational data feedback to EMS to achieve efficient operation of energy storage systems and grid scheduling.
Through the collaborative work between BMS, EMS, and PCS, energy storage systems can achieve safe and stable operation, efficient energy management, and flexible grid scheduling, thereby improving energy utilization efficiency and system reliability