Energy storage system
A complete electrochemical energy storage system is mainly composed of: battery pack, battery management system (BMS), energy management system (EMS), energy storage converter (PCS) and other electrical equipment.
In the energy storage system, the battery pack feeds the status information to the battery management system BMS, and the BMS shares it to the energy management system EMS and the energy storage converter PCS. EMS sends control information to PCS and BMS according to optimization and scheduling decisions, and controls the charging and discharging of single batteries/battery packs.
What is PCS?
The topological structure of Power Conversion System (PCS) of electrochemical energy storage system is closely related to the technical route of electrochemical energy storage system, and understanding the topological structure of PCS is of great help to understand the choice of technical route of electrochemical energy storage system.
PCS can operate in the following two states and thus shoulder two important functions:
1. The working state of the rectifier: converts the alternating current of the power grid into direct current when charging the battery of the energy storage system
2. Inverter working state: When discharging the battery of the energy storage system, the direct current of the battery is converted into alternating current and fed into the power grid;
Therefore, PCS is an important equipment to realize bidirectional energy transfer between DC cell and AC network.
In recent years, thanks to new power electronic devices including IGBTs (insulated-gate bipolar transistors), insolated gate bipolar transistor) and IGCT (integrated gate commutated thyristor) development and performance improvement, The production and application of high voltage and high power PCS devices have become a reality.
To be specific,
Battery management system BMS: plays a perception role, mainly responsible for battery monitoring, evaluation, protection and balance;
Energy management system EMS: plays a decision-making role, mainly responsible for data acquisition, network monitoring and energy scheduling;
Energy storage converter PCS: plays an executive role, the main function is to control the charging and discharging process of the energy storage battery pack, and perform AC/DC transformation.
