The charge and discharge control of energy storage power station is achieved through the battery management system (BMS) and energy storage converter equipment (PCS) in the energy storage system. Charging and discharging control is the process of adjusting the power, time, and mode of battery charging and discharging based on system operation requirements and grid scheduling requirements, in order to achieve optimal operation of energy storage systems.
1、 Charging and discharging control of energy storage power stations
1. Charging control:
Limiting charging current: By controlling the charging current, the battery can be charged too quickly or excessively, in order to reduce battery loss and shorten its lifespan.
Control charging voltage: Ensure that the charging voltage is within the appropriate range to avoid damage to the battery caused by excessively high or low charging voltage.
Charging cutoff: When the battery reaches the set SOC (State of Charge) or SOE (Remaining Charge), stop charging to avoid overcharging.
Temperature monitoring: Monitor the temperature of the battery through temperature sensors and other devices, and take measures when the temperature exceeds the safe range, such as reducing the charging and discharging rate or stopping charging and discharging.
2. Discharge control:
Limiting discharge current: By controlling the discharge current, the battery can be discharged too quickly or excessively, in order to reduce battery loss and shorten its lifespan.
Control discharge voltage: Ensure that the discharge voltage is within the appropriate range to avoid damage to the battery caused by high or low discharge voltage.
Discharge cutoff: When the battery reaches the set SOC or SOE, stop discharging to avoid excessive discharge.
2、 One charge one discharge and two charge two discharge are two common charging and discharging schemes, and the main difference between them lies in the charging and discharging modes and strategies:
1. One charge, one discharge: indicates that the energy storage station only charges and discharges once within a complete charging and discharging cycle. This strategy is relatively simple and suitable for scenarios with relatively stable demands.
2. Two charging and two discharging: This means that within a complete charging and discharging cycle, the energy storage station will perform two charging and two discharging. This strategy is usually suitable for scenarios with high demand fluctuations or frequent adjustments to the grid load. By multiple charging and discharging, it is possible to better balance the power grid load and improve energy utilization efficiency.

3、 Comparison of advantages of charging and discharging schemes

1. One charging and one discharging scheme:
Advantages: The one charging and one discharging scheme and operation are relatively simple, with low requirements for the control system, suitable for small-scale energy storage systems and stable demand scenarios. Low cost, relatively easy to operate and manage. Suitable for general distributed energy storage systems or backup power supply systems, etc.
Disadvantage: In scenarios with high demand fluctuations, it may not be possible to meet the real-time demand of the power grid, leading to a decrease in energy utilization efficiency.
2. Two charging and two discharging scheme:
2.1 Advantages:
High energy efficiency: Through multiple charging and discharging, energy can be efficiently utilized and energy utilization efficiency can be improved.
Improve the reliability of power supply: The released energy from energy storage stations can meet the peak electricity demand and better respond to the frequency regulation and peak valley balance needs of the power grid. Improve the power supply reliability of the entire power grid.
Optimizing power supply structure: The operation of energy storage power stations can optimize the power supply structure, reduce grid pressure, and reduce energy consumption. Suitable for large energy storage stations that require higher operational flexibility and grid support capabilities.
2.2 Disadvantages: High requirements for control systems require more complex algorithms and control strategies to ensure the safety and performance of batteries.
The options of one charging and one discharging and two charging and two discharging each have their own advantages and disadvantages, and the specific choice depends on actual needs and scenarios. In scenarios with high demand fluctuations, the two charging and two discharging scheme may have more advantages in grid support and scheduling, as it can better balance grid load and improve energy utilization efficiency. However, this also requires more complex control systems and algorithm support. In practical operation, selection and optimization evaluation should be based on specific requirements, cost considerations, system scale, and scenarios.