分布式多变流器型微电网无互联线潮流控制

Wireless Autonomous Power Flow Control in Converter-Fed Microgrids

当储能系统接口变流器的视在功率一定时,分布式多变流器型微电网系统内无功功率需求越大,储能系统对电源与负荷之间有功供需平衡的调节能力越弱。针对该问题,提出了一种无互联线潮流控制方法。该方法利用微电网系统内所有潜在的分布式无功补偿源提供负荷所需无功,以期减小储能系统功率调节压力。并通过下垂控制与倒下垂相结合的方法来实现电压控制模式与电流控制模式变流器间功率的合理分配。同时,分析了影响功率分配精度的因素,提出基于虚拟阻抗与自适应空载电压补偿相结合的方法改善无功功率分配精度。最后通过实时硬件在环平台验证了所提控制策略的可行性。

When total apparent power of the energy storage system （ESS） interfacing converter is fixed, the higher the requirement on reactive power in the microgrid system with distributed multiple converters, the weaker the ability of ESS to balance the active power between distributed generators and loads is. To reduce this limitation on ESS, a wireless power flow control method, which autonomously utilizes all potential distributed reactive compensation sources to supply reactive power needed by loads to mitigate the pressure of reactive power adjustment, is proposed. Droop control and reversed droop control are integrated to implement rational power allocation among voltage controlled mode and current controlled mode converters. Meanwhile, the factors impacting the accuracy of reactive power allocation are analyzed, and a method based on the combination of virtual impedance with adaptive no-load voltage compensation is proposed to improve the accuracy of reactive power allocation. Finally, real time hardware-in-the-loop results are presented to show the feasibility of proposed control strategy.