正弦稳态电路功率的分析

论文编号:JD495  论文字数:9949,页数:23   

  摘      要

功率因数是输配电系统的一项重要的经济指标。该论文首先阐述了正弦电流电路中瞬时功率、有功功率、无功功率、视在功率的概念以及三者之间的关系。接下来针对不同的负载，采用不同的方法来提高功率因数进行了研究。具体又分为两种情况:一种是在电源的输出电压和频率都不变的条件下，把电路分为容性和感性，讨论了元件参数对功率因数的影响，另一种是讨论了在元件参数不变的条件下，电源的频率和电压对功率因数的影响。通过研究得出了不同电路改善功率因数的最佳方案。
改善功率因数，主要是利用电感和电容的无功补偿。在感性负载电路中用串联容性负载的方法、在容性负载电路中用串联感性负载的方法，可以改变功率因数，但由于一般供电线路的电压是不变的，这两种方法都将影响负载的正常工作，因而不是很好的补偿方法。但在感性负载电路中用并联容性负载的方法、在容性负载电路中用并联感性负载的方法，也可以改变功率因数，而这两种方法都不会影响负载的正常工作，因而是一种很好的补偿方法。

关键词：
功率  功率因数  无功补偿

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

目     录
1.前言........................................................................1
2.正弦电流电路中的功率 .......................................................3
2.1 瞬时功率 .................................................................3
2.2 平均功率 .................................................................4
2.3 无功功率 .................................................................4
2.4 视在功率 .................................................................5
2.5 复功率 ...................................................................5
2.6 功率因数 .................................................................6
2.7 小结  ....................................................................6
3.电源电压、频率不变，元件参数对功率因数的影响 ...............................6
3.1感性电路 ..................................................................6
3.2容性负载 .................................................................10
3.3小结......................................................................13
4.元件参数不变，电源电压、频率对功率因数的影响 ..............................13
4.1感性电路..................................................................13
4.2容性电路 .................................................................14
4.3 串联电路 ................................................................14
4.4 并联电路 ................................................................14
4.5 小结 ....................................................................14
5.讨论 ......................................................................15
6.总结 ......................................................................18
参考文献 ....................................................................19
致      谢...................................................................20

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