The Research On Frequency Response Of The Fair-New DC Sensor And The Hybrid Filter

This thesis includes two sections: one is the research on frequency response of DC sensor based on magnetic potential self-balance and feed-back compensation; the other is the study of hybrid filter. The DC sensor based on magnetic potential self-balance and feed-back compensation is brought forward based on the research of basic principles about traditional DC transformer and magnetic magnifier. It combines the merits and complements of open-loop closed-loop measuring principle organically, and has the characteristics of simple construction, high precision, good stability and reliability. This paper expatiates the fundamental principle of the DC sensor and establishes the mathematical model of it. The software MATLAB has been applied to analyze the amplitude and phase frequency response characteristics. The simulation results show the frequency range of its steady operation and the approach to expand the bandwidth of the system is also presented. The rich use of power electronic devices exacerbates the harmonic hazard, and plays an important role in affecting the quality of power supplies. A new type series active power filter based on the fundamental magnetic potential self-balance and harmonic counteraction is proposed and its construction and operating principle is formulated. This paper gives a detailed analysis of the amplifying harmonic power devices, including the topological graph of the main circuit, the choice of parametrics, the design of the drive and protection circuit with its notice, the design of the control circuit, etc. The properties of the filter are summarized by experimenting on a practical filter equipment. The results of experiments prove that the design of the filter is reasonable and is simple in structure. It has perfect dynamic characteristics and cost/performance ratio. The research is summarized in the end of the thesis and gives a prospect of the future effort.