| Summary: | 博士 === 國立臺灣科技大學 === 電機工程系 === 106 === The main purpose of this dissertation is to investigate the impact of harmonic filter applications on the harmonic current distortion of Voltage Source Inverter-fed drives (VSI) and improving strategies. In general, the nonlinear loads are assumed as a constant harmonic current source in harmonic analysis of power systems. However, when an active or passive harmonic filter is invited to mitigate the harmonics produced by the VSI load, the total harmonic current distortion of the load actually changes. The increasing of the VSI total harmonic current distortion will lead to the unexpected harmonic improving result at system side, and cause insufficient harmonic carrying capability, such as the rated voltage and rated current of the passive harmonic filter.
In order to analyze the causes and main influencing factors of this harmonic changing phenomenon, a VSI equivalent circuit is established in this study, and its ac side harmonic current transformation equation is also derived in this investigation. The whole and selective harmonic compensation control models of the active harmonic filter are deduced, as well as the equivalent harmonic model of passive harmonic filters. In this reaseach, correlation analysis system models are constructed and simulated to illustrate the impact of different system short-circiut levels, VSI loadings, ac choke reactors of the VSI, and different filter compensation modes on the harmonic current distortion of the VSI. Then, the simulation and measurement results are used to summarize the causes of this phenomenon and the main influencing factors. Furthermore, this research proposed a design method for active and passive harmonic filters, which optimizes the system harmonic improvement results, and effectively solves the application problems of the active and the passive harmonic filters. Finally, from the simulation and field measurement results, the dissertation is of value to solve the harmonic improving problems on the active and passive harmonic filter applications.
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