3D-Tan-Sun Transformation Based Phase And Amplitude-Detected Technology And It's Application

The Phase-Amplitude Detective Technology(PADT)is the widely used in grid-connected applications.The main challenge that is associated with the PADT is how to precisely and fast detect the phase when the grid voltage is unbalanced.To overcome this challenge,we proposed the unbalanced PADT(UPADT)based on three-dimensional unbalanced coordinate transformation theory,i.e.3D-Tan-Sun coordinate transformation theory.This thesis firstly gave an description of the UPADT in three-phase unbalanced system in detail under some background materials based on three-dimension unbalanced coordinate transformation theory.Then we analyzed the stability of our unbalanced PADT particularly.Furthermore,we applied the UPADT to the control of split-capacitor voltage sourced converter(VSC)topology by using the sliding-mode variable structure system control(SMVC)of the inner current loop and the PI regulator based outer voltage loop,which combines with the power theory based on the 3D-Tan-Sun coordinate transformation theory when the power grid is unbalanced.Finally,the simulation was performed to verify its performance.It was shown that,on the one hand,the UAPDT can detect the phase angle and amplitude of each phase precisely and fast,and the stability results coincide with the theoretical analysis;on the other hand,this technology can be used in the control of VSC under the unbalanced electrical system.