基于ＰＷＭ ＡＣ－ＡＣ變換的電壓補(bǔ)償器設(shè)計
2008-04-12 00:00:00李昂
現(xiàn)代電子技術(shù) 2008年12期
摘 要：介紹在配電系統(tǒng)中一種新型的電壓補(bǔ)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(bǔ)償控制模塊根據(jù)系統(tǒng)控制對象的特點(diǎn)，選取數(shù)字化控制芯片TMS320LF2407，設(shè)計了基于DSP的PWM實(shí)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(fù)荷，自耦變壓器只吸收勵磁電流；而當(dāng)電壓降低時，變換器將電壓迭加（補(bǔ)償）上去，以保持負(fù)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(shè)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(yīng)速度快。
關(guān)鍵詞：配電系統(tǒng);電壓補(bǔ)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(bǔ)償技術(shù)無論是變電站的集中補(bǔ)償、用戶的分散補(bǔ)償，還是桿上補(bǔ)償，基本上都是采用成組電容器/電感等能量存儲設(shè)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(bǔ)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(shù)來驅(qū)動AC-AC變換器。當(dāng)擾動發(fā)生使得電壓降低時，本裝置能提升電壓，保持負(fù)荷端電壓為額定值。在設(shè)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(yīng)速度快。
