基于虚拟阻抗功率的无锁相环并网预同步控制

Grid-connected Pre-synchronization Control Based on Virtual Impedance Power Without PLL

储能系统通常可工作于离网模式和并网模式,实现离网模式到并网模式的平滑切换是储能系统的关键技术。若不能实现平滑并网,则系统可能会产生非常大的冲击电流,威胁系统的安全可靠靠运行。以T型三电平储能变换器系统为研究对象,为实现储能系统从离网模式到并网模式的平滑切换,在深入分析电压型虚拟同步机(VSG)控制策略的基础上,提出了一种基于虚拟阻抗功率的无锁相环(PLL)并网预同步控制策略。仿真及实验结果验证了所提控制策略的正确性及有效性。

Energy storage system can usually work in the off-grid mode and the on-grid mode.Smooth switching from the off-grid mode to the on-grid mode is the key technology of the energy storage system.If it can’t connect to the grid smoothly,the system may have a very large inrush current,and threaten the safe and reliable operation of the system.The T-type three-level energy storage converter system is taken as the research object.In order to realize the smooth switching of the energy storage system from the off-grid mode to the on-grid mode,based on the in-depth analysis of the control strategy of the voltage-type virtual synchronous generator(VSG),grid-connected pre-synchronization control strategy based on virtual impedance power without phase-locked loop(PLL) is proposed.The simulation and experimental results verify the correctness and effectiveness of the proposed control strategy.