正弦穩態電路功率的分析

電子機電論文編號:JD495  論文字數:9949,頁數:23   

 目     錄
1.前言........................................................................1
2.正弦電流電路中的功率 .......................................................3
2.1 瞬時功率 .................................................................3
2.2 平均功率 .................................................................4
2.3 無功功率 .................................................................4
2.4 視在功率 .................................................................5
2.5 復功率 ...................................................................5
2.6 功率因數 .................................................................6
2.7 小結  ....................................................................6
3.電源電壓、頻率不變，元件參數對功率因數的影響 ...............................6
3.1感性電路 ..................................................................6
3.2容性負載 .................................................................10
3.3小結......................................................................13
4.元件參數不變，電源電壓、頻率對功率因數的影響 ..............................13
4.1感性電路..................................................................13
4.2容性電路 .................................................................14
4.3 串聯電路 ................................................................14
4.4 并聯電路 ................................................................14
4.5 小結 ....................................................................14
5.討論 ......................................................................15
6.總結 ......................................................................18
參考文獻 ....................................................................19
致      謝...................................................................20

摘      要

功率因數是輸配電系統的一項重要的經濟指標。該論文首先闡述了正弦電流電路中瞬時功率、有功功率、無功功率、視在功率的概念以及三者之間的關系。接下來針對不同的負載，采用不同的方法來提高功率因數進行了研究。具體又分為兩種情況:一種是在電源的輸出電壓和頻率都不變的條件下，把電路分為容性和感性，討論了元件參數對功率因數的影響，另一種是討論了在元件參數不變的條件下，電源的頻率和電壓對功率因數的影響。通過研究得出了不同電路改善功率因數的最佳方案。
改善功率因數，主要是利用電感和電容的無功補償。在感性負載電路中用串聯容性負載的方法、在容性負載電路中用串聯感性負載的方法，可以改變功率因數，但由于一般供電線路的電壓是不變的，這兩種方法都將影響負載的正常工作，因而不是很好的補償方法。但在感性負載電路中用并聯容性負載的方法、在容性負載電路中用并聯感性負載的方法，也可以改變功率因數，而這兩種方法都不會影響負載的正常工作，因而是一種很好的補償方法。

關鍵詞：
功率  功率因數  無功補償

Abstract

Power Factor is an important economic indicator in transmission and distribution power system. First, the paper gives a brief introduction on the relationships among the sine current circuit instantaneous power, active power, reactive power, apparent power. Second, in accordance with the different loads, the paper tries to explain how to improve the power factor with different methods. This can also be divided into two categories: one is to discuss the influence of power factor by way of dividing power circuit into capacitive and emotional under the circumstance of unchangeable voltage and frequency of output power, and the other is discussed the influence from voltage and frequency of power to power factor with the situation of constant component parameters. The paper draws a best conclusion on how to improve the power factor in different power circuit.
It usually uses the reactive power compensation of inductors and capacitors to improve the power factor. You can change the power factor by way of using tandem capacitive loading In emotioal load circuits, and also by way of using tandem emotional loading in capacitive load circuits. However, generally speaking, due to the constant of voltage, these two methods will affect the normal work load; they cannot be called good methods. But if we use tandem capacitive loading in emotional load circuits and use tandem emotional loading in capacitive load circuits, the power factor can be improved and the work load will not to be influenced. So, it’s a excellent way to compensate.
Key words: Power ,  Power Factor,   reactive power compensation