引入虚拟阻抗的并联逆变器新型下垂控制策略

摘要

Due to the different line distances between each of the inverters in the parallel operating micro-grid in-verter system, resulting in its total output impedance different and presenting impedance characteristics, the tradi-tional droop control can not be properly used, and the system can not achieve the accurate power distribution.To solve this problem, based on the traditional theory of the droop control algorithm, this paper proposes a new droop control strategy by introduction of a new virtual impedance.When the load mutates, the control strategy can guar-antee bus voltage amplitude and frequency stable, suppress reactive circulation between the two inverters system, and precisely allocate active power and reactive power.The strategy further introduces the power differential part that can improve the system dynamic response.The simulation results verify the reliability of the control strategy.%在微网逆变器并联运行系统中,由于各逆变器之间的线路距离不同,导致其输出总阻抗不同且呈阻抗特性,传统的下垂控制无法得到正确运用,系统不能实现功率精确分配.为了解决这个问题,本文在传统下垂控制算法理论的基础上,提出一种引入虚拟阻抗的新型下垂控制策略.当负载突变时,该控制策略能保证母线电压幅值和频率的稳定,抑制两台逆变器系统之间的无功环流,实现系统有功、无功的精确分配,并且通过引入功率微分环节,提高了系统的动态响应.仿真分析验证了本文控制策略的可靠性.