Study On Unite PF ML Converters With High Dynamic Performance

A comprehensive study on unite power factor converters (UPFC) with high dynamic performance is performed,and operation principles and topology derivation method of multi-level (ML) rectifiers with high dynamic performance are illustrated in this dissertation. Control scheme of three-level (TL) is improved by theoretical analysis and simulation, which is verified by experiment results at last.Above all a single phase eigtht-switch TL UPFC is introduced and its operation principle and state equatuions in each stges are also illustrated. Then the general mathematical mode (GMM) of the single phase TL rectifier and its equivalence circuit are built.Based on GMM, two equivalence ML arms --type I and II are introduced from which several novel ML rectifiers are derivated by double ML and multi ML method respectively, whose merits and shortcomings are compared and verified by simulation results.Space vector pulse width modulation (SVPWM) is introduced in TL rectifier and its scheme is presented. Its dynamic performance is compared by average control. Then a fuzzy proportional integral differential (PID) is put forward against load dependence of PWM rectifiers, improving the bad dynamic performance of tranditional PID, and is verified by simulated waves furtherly.Control model of UPFC is built and an all-round evaluation system on UPFC dynamic performance is set up, including qualific and quantificatic ways, and normative rules of power flow chart. Finally, the dynamic performance of the single phase TL rectifier is analysised.A single phase eight-switch TL rectifier is designed with a digital signal processor (DSP) implementing SVPWM. A prototype of 1KW is successfully constructed and then the theoretic analysis and simulations are verified by the experimental results, in which PF is near 1.