【摘要】 针对低压电网系统中三相不平衡负载造成的零序电流问题,提出在两相旋转坐标系下引入有功分量的改进i_p-i_q电流检测法,通过提取负载电流中的谐波、无功和不平衡分量,在不同功能模式下合成补偿电流.同时为了实现对补偿电流的快速准确跟踪,提出将PI与重复控制组合并联的复合控制器来设计逆变器输出电流控制环.最后利用MATLAB建立系统模型,并添加在多功能模式下的小扰动分析,通过仿真验证系统设计的合理性和控制策略的有效性.该系统能够根据实际需要切换工作模式,实现并网发电和有源滤波功能的统一调控,使并网逆变器效益最大化.更多还原

【Abstract】 Aiming at the zero-sequence current problem caused by three-phase unbalanced load in low-voltage power grid system, an improved i_p-i_q current detection method for introducing active component in two-phase rotating coordinate system is proposed.By extracting harmonics, reactive and unbalanced components in the load current,synthesizing compensation current in different function modes.At the same time,in order to realize the tracking of the compensation current quickly and accurately,a composite controller with a combination of PI and repetitive control is proposed.Finally,the system model is established by using MATLAB,and the small disturbance analysis in multi-function mode is added.The rationality of the system design and the effectiveness of the control strategy are verified by simulation.The system can switch the working mode according to actual needs,realize unified control of grid-connected power generation and active filtering functions,and maximize the benefit of grid-connected inverters.更多还原