Study On Ac-ac Excitation System For Harmonic Control Ac Excited Generator

AC excited generator (ACEG) is a new kind of generator. It has superior performances such as good stability, variable speed constant frequency (VSCF) generation, active power and reactive power regulation independently and lag reactive power absorbing deeply. It is very suitable for hydroelectricity set, pump storage groups and wind power generation groups. Excitation control system is the main component of the AC excited generator system, directly determine the properties of AC excited generator system. In this thesis, the main purpose is research the excitation control system of ACEGThis thesis introduces the mathematical models of ACEG in static three-phase coordinate and the mathematical models of ACEG in rotary two-phase coordinate. This thesis also introduce the expressions of active power and reactive power of stator and rotor,This thesis researches vector control of ACEG system and adopts the vector control strategy of stator field oriented (SFO). This thesis fixs the control strategy of ACEG VSCF generation and decoupling control of active power and reactive powerThis thesis designs the ACEG excitation system for the given experimental units. In power units, through the analysis and comparison of the frequency converters and think about the laboratory condition, this thesis adopts AC-AC frequency converter, then designs the main circuit structure and components. In control units, this paper designs the ac signal detection link, speed detection link, pulse trigger circuit links etc auxiliary circuit and the control main circuit based on TMS320F2812 DSP. The paper completes the software design of the excitation control system using C language and assembly language.This thesis builts detailed simulation model of ACEG system which includes AC excited generator,regulator,AC-AC frequency converter,excitation transformer. Based on this model, the harmonic analysis and suppression were researched. So I bring up single-tuned filters on the stator side to restrain harmonics and built up filter parameters optimization model. Then design and optimize filter parameters by the gatool software in the genetic algorithm Toolbox of MATLAB. After adding the filters to the system the THD of the stator current greatly reduced. The results show that the filters can be veryeffective.