電力系統(tǒng)及其自動(dòng)化外文翻譯--實(shí)時(shí)檢測諧波和單相電路無功功率的方法(已修改)
2025-01-20 10:06 本頁面
【正文】 外文原文 1 RealTime Method for Detecting Harmonic and Reactive Currents of SinglePhase Circuits Abstract According to the characteristics of singlephase circuits and demand of using active filter for realtime detecting harmonic and reactive currents, a detecting method based on Fryze39。s power definition is proposed. The results of theoretic alanalysis and simulation show that the proposed method is effective in realtime detecting of instantaneous harmonic and reactive currents in singlephase circuits. When only detecting the total reactive currents， this method does not need a phaselocked loop circuit, and it also can be used in some special applications to provide different pensations on the ground of different requirements of electric work. Compared with the other methods based on the theory of instantaneous reactive power, this method is simple and easy to realize. Keywords Active filter。 Harmonic。 Reactive current。 Realtime detection。 Singlephase circuit。 Electricwork 0、 Introduction At present it is a major tendency to limit harmonics with active filters??31? ， which can not only limit harmonics dynamically and pensate reactive power but also can achieve a continuous and dynamic tracking of the pensation for timevarying harmonic and reactive currents and are not apt to be affected by the resistance of electric work. The key technology of active filter is the realtime detecting of harmonics and reactive currents from load currents to receive reference to meet the need of the active ， the result of the filter will be influenced by the accuracy and realtime ability of the detection. On the basis of the theory of instantaneous reactive power in threephase circuit，many relatively mature detecting algorithms for harmonics and reactive currents of threephase circuits have been proposed， such as the methods of p, q, ip and ? ?41?qi However, in singlephase circuits， these methods can not be directly used and an extra 外文原文 2 twophase voltage and current need to be constructed， which lowers the realtime ability and makes the algorithm more plicated. Refs. [1 ,5] presented a method that is construeted on the basis of Fryze39。s power definition, but it needs one integral cycle before educing the detection results. Since 1980s， many researchers, .Czarnecki ??6 , have analyzed the nonsinusoidal currents with new methods, but one integral cycle is alsoneeded and the realtime ability is still poor. In this paper, an indepth research is made on Fryze39。s power definition， which is applied to detect harmonic and reactive currents in singlephase circuits successfully，and a realtime detecting method for harmonic and reactive currents in singlephase circuits is brought forward. Analysis and simulation reveal that the proposed method can realize realtime detection of the instantaneous harmonic and reactive currents in singlephase circuits. This method does not need a phaselocked loop circuit when only detecting the total reactive currents， and can provide different pensations on the ground of different requirements of electric work. Compared with other methods with the theory of instantaneous reactive power, this method is simple and easy to realize. The method of detecting reactive power and harmonic currents presented in the Ref.[7] is a special case of application of our method. Fundamentals According to Fryze39。s power definition ??5 ， instaneous active currents is a ponent of the total currents and its waveform is the same as that of voltage Moreover, the average power absorbed by active currents in one cycle is equal to that by total currents， and substraction of the instantaneous active currents from the total currents yields the instantaneous reactive ， we have the following expression: ? ? ? ?,tGuti sp ? (1) ? ? ? ? ? ? ? ? tpT sTtsT sT dtitudtitup ?? ?? 0101 (2) ? ? ? ? ? ?,tititi psq ?? (3) where ??tip and ??tiq are instantaneous active and reactive currents， respectively。 外文原文 3 ??tus and ??tis are instantaneous voltage and instantaneous current of electric work, respectively。G is real constant ratio， and P is average active power (if U is the effective value of voltage， then 2/UPG? )。T is cycle and t is time. As indicated by Eqs.(1)， (2)and( 3)， G can be calculated if the average active power and the square of voltage virtual value are from
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