并网逆变器不平衡电网下的分析.ppt

单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,单击此处编辑母版标题样式,*,Grid-tied inverter under unbalanced grid voltage,Background,Three phase variables,(,x,a,x,b,x,c,),-1,can be represented by a vector in the a-b-c coordination,Three phase variables can be transformed into coordination,Background,If ,the trajectory of the vector will be in the plate,If the three phase variables are in three phase sine signal with the same amplitude and frequency of ,and with the phase difference of 120 degree,the vector will rotate in the plate,Negative sequence rotate in clockwise direction,Positive sequence rotate in counter-clockwise direction,Background,Positive rotation coordination,Negative rotation coordination,Background,The model of inductor in POSITIVE&NEGATIVE rotation coordination,In the phasor diagram,the voltage leads the current by 90 degree,In the sector diagram,the relationship also exists in both positive rotation coordination and negative rotation coordination,In the positive rotation coordination,the,V,L,and,I,L,represents positive sequence only,they will rotate in counter-clockwise and,V,L,must lead,I,L,(the leading direction is counter-clockwise),In the negative rotation coordination,the,V,L,and,I,L,represents negative sequence only,they will rotate in clockwise and,V,L,must lead,I,L,(the leading direction is clockwise),Background,Rotating coordination,Positive sequence,Negative sequence,T,p,DC,-2,T,n,2,DC,Phase lock loop,。