摘 要:介紹在配電系統(tǒng)中一種新型的電壓補償器,即在自耦變壓器中集成PWM AC-AC變換器(每相4個IGBT元件。其電壓補償控制模塊根據(jù)系統(tǒng)控制對象的特點,選取數(shù)字化控制芯片TMS320LF2407,設計了基于DSP的PWM實現(xiàn)方式。在正常工作狀況下,PWM變換器工作在旁路方式,電源功率直接傳輸給負荷,自耦變壓器只吸收勵磁電流;而當電壓降低時,變換器將電壓迭加(補償)上去,以保持負荷端電壓為額定值,同時通過自耦變壓器增加一定的輸出功率。在設計中沒有使用諸如成組電容器/電感等這些儲能元件,造價低,響應速度快。
關鍵詞:配電系統(tǒng);電壓補償器;自耦變壓器;PWM AC-AC變換
Design of Voltage Compensator Based on PWM AC-AC Conversion
LIAng
(Shaanxi University of Technology,Hanzhong,723003,China)
Abstract:In this paper a new voltage compensator in electric distribution system is discussed,the design employs a PWM AC-AC converter (4,IGBTs per-phase along with an auto-transformer.According to the features of control object,the proposed scheme employs TMS320LF2407,designing the PWM implement mode based on DSP.Under normal conditions the approach works in by-pass mode,delivering utility power directly to the load and the auto-trsformer draws only magnetizing current.During a disturbance such as voltage sag,the PWM converter adds the missing voltage and some amount of power is handled via the auto-trsformer,helps in maintaining rated voltage at the terminals of the critical load.The approach does not employ any energy storage components such as bulk capacitors/inductors and provides fast response at low cost.
eywords:electric distribution system;voltage compensator;auto-transformer;PWM AC-AC conversion
研究表明配電系統(tǒng)中90%以上的擾動都是由電壓降低引起的,常用的低壓補償技術無論是變電站的集中補償、用戶的分散補償,還是桿上補償,基本上都是采用成組電容器/電感等能量存儲設備,造價都比較高。
本文介紹配電系統(tǒng)中針對重要用戶的一種新型電壓補償器,即在用戶自耦變壓器中加裝PWM AC-AC變換器,通過換流技術來驅(qū)動AC-AC變換器。當擾動發(fā)生使得電壓降低時,本裝置能提升電壓,保持負荷端電壓為額定值。在設計中沒有使用諸如成組電容器/電感等這些儲能元件,造價低且響應速度快。