Research On Three-level STATCOM Based On Selected Harmonic Elimination Method

In the 1990's,the full-controlled power electronic devices has been developed rapidly,power electronics technology has been widely used in the power systems.The development of the flexible AC transmission technology is the most rapid,as its core technology,static Var compensator has become a hotspot for distribution equipment because of advanced control mode and good dynamic/static compensation effect.Firstly,the common three-level STATCOM mathematical model is established.Secondly,the principle of the special harmonic elimination method for unipolar and bipolar is analyzed and the corresponding nonlinear equation is established.the switching angles throughout the whole modulation range is solved by the Newton iterative method based on the Jacobian matrix at the different number of switching angles.A three-level STATCOM model based on speci fic harmonic elimination modulation is established by PSIM.The simulation results show that the switching angles solved by this method can eliminate specific harmonics,so that the three-level STATCOM can function normally.In the end,the experiment platform of 7.5kVar three-level STATCOM is built based on the TMS320F28335.Through the software design of the specific harmonic elimination method,the experiment is accomplished and the validity and correctness of the method is verified.