基本电路理论课程论文2006-2007第一学期.PDFVIP

基本电路理论课程论文 2006-2007 第一学期 A discussion about maximum power transfer 夏海颖，包雪娜，李光北，张引玉，杨阳 Outline: In this record, we will discuss the problem of maximum power transfer in resistor circuit and sinusoidal steady-state circuit. And for the cases of three-phase circuit, we will compare it with other circuits to show that it is the most efficient circuit for maximum power transfer. Finally, we will give some applications in maximum power transformation to verify that this issue is quite useful in real life. Key words: maximum power transfer, resistor circuit, sinusoidal steady-state circuit, three-phase circuit, Applications. Chapter One: Linear Circuit The Thevenin equivalent is useful to find the maximum power a linear circuit can deliver to a load. As shown in the figure (1), the power delivered to the load is 2 ⎛ V Th ⎞2 p i R L ⎜⎜ ⎟⎟RL …………………… ① R R + Th ⎝ L ⎠ Figure （1） Figure (2) For a given circuit , V and R are fixed .By varying the load resistance R ,the power Th Th L delivered to the load varies as sketched in figure(2).We can see that when RL is equal to RTh ,the maximum power occurs. We take differential about p in Eq. ① with respect to RL and set the result to zero. V 2 R R