Build a hybrid energy storage system model
In Simulink, you first need to build a hybrid energy storage system model with supercapacitors and batteries connected in parallel. Among them, the state of charge (SOC) of supercapacitors and batteries needs to be managed according to actual conditions. The state of charge can be obtained by measuring the voltage, current, etc. of the battery and supercapacitor and then integrating them.
Energy Management of Supercapacitors
For energy management of supercapacitors, power distribution can be performed through low-pass filters to suppress power fluctuations. At the same time, energy management can be performed based on the SOC of the supercapacitor. For example, when the SOC is higher, the battery can be discharged more; when the SOC is lower, the battery can be discharged less. When the SOC is very low, charging is required. These operations can be achieved through bidirectional switches of batteries and supercapacitors.
Battery energy management
A similar approach can be used for battery energy management. Single-loop constant current control can be used to achieve effective energy management by controlling the battery current. According to the SOC of the battery, corresponding operations can be performed in the discharge lower limit area, discharge warning area, normal working area, charging warning area, and charging upper limit area.
Grid-connected inverter control
Finally, the DC side voltage of the hybrid energy storage system needs to be inverted into AC voltage and connected to the grid. This can be achieved with a three-phase inverter. The inverter can adopt a voltage and current double closed-loop PI control strategy to achieve effective energy control through PWM modulation.
overall model
