Lecture Notes14_AcPower

1 analysis of circuits 2013 3867 ac power 14 6 11

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Unformatted text preview: Power Factor Correction • Ideal Transformer • Transformer Applications • Summary For any impedance, Z , complex power absorbed: S = V I ∗ = P + jQ Using (a) V = I Z (b) I × I ∗ = I Resistor: S = I 2 R= |V | 2 we get S = I 2 Z= |V | 2 Z∗ 2 φ=0 R Absorbs average power, no VARs (Q = 0) Inductor: S = j I 2 ωL = j |V | 2 φ = +90◦ ωL No average power, Absorbs VARs (Q > 0) |I | 2 Capacitor: S = −j ωC = −j V 2 ωC φ = −90◦ No average power, Generates VARs (Q < 0) E1.1 Analysis of Circuits (2013-3867) AC Power: 14 – 6 / 11 Power in R, L, C 14: Power in AC Circuits • Average Power • Cosine Wave RMS • Power Factor • Complex Power • Power in R, L, C • Tellegen’s Theorem • Power Factor Correction • Ideal Transformer • Transformer Applications • Summary For any impedance, Z , complex power absorbed: S = V I ∗ = P + jQ Using (a) V = I Z (b) I × I ∗ = I Resistor: S = I 2 R= |V | 2 we get S = I 2 |V | Z= 2 Z∗ 2 φ=0 R Absorbs average power, no VARs (Q = 0) Inductor: S = j I 2 ωL = j |V | 2 φ = +90◦ ωL No average power, Absorbs VARs (Q > 0) |I | 2 Capacitor: S = −j ωC = −j V 2 ωC φ = −90◦ No average power, Generates VARs (Q < 0) VARs are generated by capacitors and absorbed by inductors E1.1 Analysis of Circuits (2013-3867) AC Power: 14 – 6 / 11 Power in R, L, C 14: Power in AC Circuits • Average Power • Cosine Wave RMS • Power Factor • Complex Power • Power in R, L, C • Tellegen’s Theorem • Power Factor Correction • Ideal Transformer • Transformer Applications • Summary For any impedance, Z , complex power absorbed: S = V I ∗ = P + jQ Using (a) V = I Z (b) I × I ∗ = I Resistor: S = I 2 R= |V | 2 we get S = I 2 Z= |V | 2 Z∗ 2 φ=0 R Absorbs average power, no VARs (Q = 0) Inductor: S = j I 2 ωL = j |V | 2 φ = +90◦ ωL No average power, Absorbs VARs (Q > 0) |I | 2 Capacitor: S = −j ωC = −j V 2 ωC φ = −90◦ No average power, Generates VARs (Q < 0) VARs are generated by capacitors and absorbed by inductors The phase, φ, of the absorbed power, S , equals the phase of Z E1.1 Analysis of Circuits (2013-...
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This document was uploaded on 02/20/2014 for the course EE 101 at WVU.

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