Application of LEM Sensors in UPS Parallel Operation System LI Wu-hua, YAN Hui-qiang ABSTRACT: The wide application of UPS is employed in sensitive condition. UPS parallel operation is adopted to distribute the output current and improve the system reliability. The instantaneous output current sharing scheme is analyzed in this paper. The voltage and current LEM sensors are applied to sample the output voltage, inductor current and output current for control. Because of their isolation and accurate sample, the UPS system has advantageous performance with reduced circulating current, low voltage THD and fast dynamic response. The experimental results verify the analysis. KEY WORDS: inverters parallel system; instantaneous current- sharing control; LEM sensor 摘要: UPS在很多重要場合得到越來越廣泛的使用。UPS并聯(lián)系統(tǒng)可以實現(xiàn)負載電流均分,提高系統(tǒng)的可靠性,成為工業(yè)使用的熱點。本文分析了UPS并聯(lián)的瞬時電流控制方法。由于LEM傳感器的良好隔離性和采樣精度,電壓LEM和電流LEM用于逆變器的輸出電壓、電感電流、輸出電壓采樣。本文設計的UPS系統(tǒng)具有環(huán)流小、輸出電壓THD低、動態(tài)響應快的優(yōu)點。實驗結果驗證了分析的正確性。 關鍵詞:逆變器并聯(lián)系統(tǒng); 電流瞬時值均流控制; LEM傳感器 1引言 為了向關鍵負載提供純凈、高性能、高可靠性的電源,UPS越來越廣泛的用于銀行、證券、航空和軍事等重要部門[1]。同時,越來越多的民用場合也開始使用UPS來保證供電系統(tǒng)的穩(wěn)定性。目前國內(nèi)大容量的UPS將達到9000臺/年的需要,并以15%以上的速度增長。市場客觀,前景很好。為了提高系統(tǒng)的冗余性,UPS并聯(lián)方案成為技術和市場的熱點。在逆變器并聯(lián)系統(tǒng)中,各個模塊分擔負載電流、便于能量分配;具有冗余功能,系統(tǒng)可靠性高;同時具有易于模塊化、標準化、良好的維護性等優(yōu)點。如何減小環(huán)流是逆變器并聯(lián)技術的重點和難點。在各種并聯(lián)方案中,基于電流瞬時值的均流控制策略,由于具有電壓調(diào)整率好、動態(tài)響應快、均流效果佳,而被廣泛的研究和應用[2,3]。 本文在分析UPS并聯(lián)系統(tǒng)的基礎上,分析了LEM傳感器在其中的重要意義。討論了LEM傳感器參數(shù)對系統(tǒng)的影響.最后給出相關實驗和結論。 2 逆變器并聯(lián)方案
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