To improve the utilization rate and economic benefits of the energy storage system and enhance the support performance of energy storage for the safe operation of the power grid, this article proposes a switching control strategy for an energy storage system based on multi-layer logic judgment to maximize energy storage benefits and ensure safe and stable power grid operation.
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What is a switching control for a PV storage system?
A novel switching control for a PV storage system with a GFL/GFM control structure was proposed in response to this challenge. By leveraging integrators and the state follower method, a smooth switching control strategy between these two control modes was facilitated, ensuring stable operation across varying grid strengths.
How a parallel PV energy storage VSG system works?
Three parallel PV energy storage VSG system using state-following method is also free of switching perturbations at PCC point for current and grid-connected power and is capable of achieving smooth switching control. However, there is a dynamic response delay.
What happens when PV energy storage VSG system is switched?
Figure 25 a shows that when PV energy storage VSG system is switched from grid-connected (island) to island (grid-connected) operation mode, output current of single PV energy storage VSG system at the direct switching instant has a large disturbance current, which is not conducive to system stable operation.
Are PV energy storage VSG system output grid-connected power free of switching perturbation?
Figure 20 b, c, and d shows that single PV energy storage VSG system output grid-connected power, DC bus voltage, and ESS charge/discharge power at the switching instant are almost free of switching perturbation, and soon returns to normal values after switching.
Can PV energy storage system realize secondary frequency and voltage regulation?
Figure 20 g and h shows that system can realize secondary frequency and voltage regulation during island switching to grid connection operation. When grid fault occurs, PV energy storage microgrid needs to be switched from grid-connected to island operation mode, to ensure the uninterrupted power supply to critical loads in the local area.
Figure 20 a shows when photovoltaic storage VSG system based on the consistency theory method is switched from island to grid-connected operation mode, output current of single photovoltaic storage VSG system at the switching instant can be switched smoothly and system response is fast during the switching.