CH11_非正弦周期电流电路和信号

# i k r i 2 r 7 2 u 50 846 cos t 30

This preview shows page 1. Sign up to view the full content.

This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: m ⋅ cos( kωt + Ψk ) k =1 = U 0 + U ( 1 )m ⋅ cos( ωt + Ψ1 ) + U ( 2 )m ⋅ cos( 2ωt + Ψ2 ) + .....U ( k )m ⋅ cos( kωt + Ψk ) + ..... 电流源： i s ( t ) = I 0 + I ( 1 )m ⋅ cos( ωt + Ψ1 ) + I ( 2 )m ⋅ cos( 2ωt + Ψ2 ) + .....I ( k )m ⋅ cos( kωt + Ψk ) + ..... 5 二、 有效值 ∞ 设 i ( t ) = I 0 + ∑ I km ⋅ cos( kωt + Ψk ) k =1 则： 2 I = I 0 + I (21 ) + I (22 ) + .... + I (kk ) + .... 其中 I ( k 为电流的 k 次谐波分量的有效值 ) 2 2 2 k 同理可得： U = U 0 + U ( 1 ) + U ( 2 ) + .... + U ( k ) + .... 例1： 有一非正弦周期电压 : u = 10 + 141.4 cos( ωt + 30° ) + 70.7 cos( 3ωt − 90° )V ,求电压的有效值。 解： 2 2 2 U = U 0 + U 1 + U 3 = 10 2 + ( = 10 2 + 100 2 + 50 2 = 112.2V 141.4 2 70.75 2 ) +( ) 2 2 6 三、平均功率 ∞ 设 i ( t ) = I 0 + ∑ I km ⋅ cos( kωt + Ψk ) k =1 ∞ u( t ) = U 0 + P = U0 I0 + ∑ U km ⋅ cos( kωt + Ψk ) k =1 ∞ ∑ U k I k cos ϕ k k =1 2 2 2 2 P = I 0 R + I1 R + I 2 R + ... + I k R + ... = I 2 R...
View Full Document

## This document was uploaded on 01/12/2014.

Ask a homework question - tutors are online