The Analysis and Design of the Current-limiting Control Strategy Based on Voltage Source Operation of Energy Storage Inverters

With the increase in the penetration rate of new energy sources into the grid, the voltage of distribution networks in some areas is susceptible to disturbances, leading to a decrease in grid robustness. Energy storage can effectively mitigate the fluctuations of new energy sources. When energy storage inverters are connected to weak grids, they can operate in voltage-source mode to enhance grid characteristics. However, in this case, the ability of current control decreases. There is a risk of overcurrent issues during the switching of high-power loads. Therefore, current limiting control is needed. When applying the current limiter to inverters operated in voltage-source mode, it can lead to voltage desynchronization, causing instability. Thus, this paper proposes a current limiting control strategy based on phase angle switching for energy storage inverters operated in voltage-source mode. Taking the droop control as an example, this paper compares the current-limiting strategy based on virtual impedance with the current-limiting strategy based on phase angle switching. From simulation results, this paper demonstrates the effectiveness of the proposed control strategy.