基于储能型逆变电源有功增量控制的故障穿越控制策略

电网侧短时故障给分布式发电(DG)并网可靠性带来挑战,常规的以抑制过电流和通过无功注入支撑并网接入点电压的方式实现故障穿越难以有效解决DG源-荷功率失衡的问题.为此提出一种基于储能型准Z源逆变器(QZSI)有功功率增量控制的故障穿越控制策略,在QZSI直流链引入超级电容器储能及控制,利用超级电容快速放电特性和QZSI较强的抗负荷冲击能力,快速调节DG并网功率增量以补偿网侧故障潮流,有效改善故障暂态时DG源-荷功率平衡,增强了DG适应短时故障负荷潮流的能力和对网侧电压的支撑能力.仿真和实验结果验证了所提故障穿越控制策略的有效性.

Fault ride-through control strategy based on active power increment control of energy-stored inverter

The grid-connected reliability of DG(Distributed Generation) is posed challenges under grid-side short-term faults. By the conventional fault ride-through control method of suppressing overcurrent and compensating reactive power to support voltage of grid-connected access point, it is difficult to effectively eliminate the imbalance of DG source-load power. A fault ride-through control strategy based on active power increment control of the energy-stored QZSI(Quasi-Z-Source Inverter) is proposed. The supercapacitor energy storage and its control are introduced in the QZSI DC link, and the fast discharge characteristics of supercapacitor and the strong resistance to load impact of QZSI are utilized to rapidly adjust the output power increment of grid-connected DG. Thus, the grid-side fault power flow can be compensated, the source-load power balance of DG during fault transient can be effectively improved, and the abilities of DG to adapt to short-term fault power flow and to support grid-side voltage are enhanced. The simulative and experimental results verify the effectiveness of the proposed fault ride-through control strategy.