Study On A New Shunt Hybrid Active Power Filter In The HVDC System

The hybrid active power filter (HAPF) is one of the key equipments applied in HVDC system. This paper studies a new shunt hybrid active power filter, analyzes its circuit and does many simulation experiments on its AC and DC side.In our country, researches on the HVDC harmonic suppression equipment mostly focus on its AC side and the research of DC side is only underway. Firstly, this paper analyzes the HVDC harmonics. Considering the AC side harmonics analysis is detailed in many literatures, we mainly analyze the DC side harmonics. Finally we find the peculiarities of its characteristic and non-characteristic harmonics. These conclusions supply the theory base for the harmonics detection.The HVDC system harmonics detection methods have some differences between the AC side and DC side, but the AC side harmonics detection methods which are the foundations of the DC side harmonics detection methods are more representatinve, so in this paper we only emphasizely study the AC side harmonics detection methods. In this part we improve the ip - iq harmonics detection method:by replacing theconventional lower-pass filter(LPF) with integrals,time-delay circuits and amplifier, it can reduce the delay-time from one cycle to 1/6 cycle and it has better real-time capability.Harmonic suppression is a ultima aim in our research. The fourth chapters of this paper briefly compare the characteristics and principles between passive filter(PF) and active power filter(APF),and based on this result, we introduce a new shunt hybrid AC active power filter(HAPF), give its topology and analyse its circuit; Study a new shunt hybrid DC active power filter based on hysteresis control,explain its design basis and principle, analyse its circuit and study its control circuit.Compared to the conventional APF topology, the proposed approach employs lower running voltage, can be controlled easily and has lower noise.The paper modifies the AC and DC system impedances and filter parameters depending on the HVDC system CIGRE standard model and establishs a new simulation model to simulate the system by Matlab. By comparing the three simulation waves of installing no filter, only PF filter and new shunt hybrid active power filter, we validate the filtering characteristics of the new shunt hybrid active power filter.