不对称电压暂降情况下光伏逆变器输出电流峰值的控制策略  

A Control Strategy for Peak Output Current of PV Inverter Under Unbalanced Voltage Sags

作　　者：谭骞[1] 徐永海[1] 黄浩[1] 刘海涛[2] 吕志鹏[2] 艾欣[1] 

机构地区：[1]华北电力大学电气与电子工程学院,北京市昌平区102206 [2]中国电力科学研究院,北京市海淀区100192

出　　处：《电网技术》2015年第3期601-608,共8页Power System Technology

基　　金：国家自然科学基金项目(51277069);国家电网公司基础性前瞻性科技项目(PD17-14-003)~~

摘　　要：不对称电压暂降在电网实际运行中时有发生,此时电压负序分量的出现将导致光伏逆变器输出功率波动和三相电流畸变;同时电压暂降情况下电压幅值的降低使得输出电流峰值的增大,进而给光伏系统运行带来安全隐患。为此,需进行不对称电压暂降情况下光伏逆变器输出电流峰值控制策略的研究。对目前研究较为广泛的不对称电压暂降情况下光伏逆变器控制方法进行了分析,着重研究了光伏逆变器的三相输出电流,给出了三相电流峰值和可能出现的最大电流峰值的计算方法,进而提出了限制电流峰值的方法,能够保证不对称电压暂降情况下光伏逆变器输出电流不会超出最大电流限值。仿真分析验证了所提方法的有效性。Unbalanced voltage sags often occur during actual power grid operation and the appearance of negative-sequence component of grid voltage leads to the output power fluctuation of PV inverters and the distortion in three-phase current caused by harmonics; meanwhile, during the voltage sag the decrease of voltage amplitude makes the peak output current increased and further brings the potential safety hazard to the operation of PV generation system, thus it is necessary to research the control strategy for peak output current of the PV inverter during unbalanced voltage sag in power grid. The approaches for peak output current of the PV inverter during unbalanced voltage sag, which are widely being researched, are analyzed, and the three-phase output current of the PV inverter is emphatically researched and a computing method for the three-phase peak current and the maximum peak current that is likely to appear is given, and then a method to restrict the peak current, by which it can be ensured during unbalanced voltage sag that the output current of PV inverters will not exceed over the limit of the maximum current, is put forward. The validity of the proposed method is verified by simulation results.

关 键 词：光伏逆变器 不对称电压暂降 控制策略 电流峰值 

分 类 号：TM721[电气工程—电力系统及自动化]