THREE-PHASE CONTROLLED RECTIFIER

The majority of line-commutated rectifier/inverter used in industry operates on three-phase networks. Although their operation is more complex than single-phase rectifiers/inverters, they posses following advantages.

Greater power transfer capability
The output ripple current is reduced

The delay/firing angle is measured from the point where two line voltages are simultaneously at the same level.

THREE-PHASE WAVE FORMS

EQUATIONS FOR THREE-PHASE VOLATGE

The three line-to-neutral voltages are given by (V_m is the peak phase voltage):

${V_{an}} = {V_m}\sin \omega t$

${V_{bn}} = {V_m}\sin \left( {\omega t - \frac{{2\pi }}{3}} \right)$

${V_{cn}} = {V_m}\sin \left( {\omega t + \frac{{2\pi }}{3}} \right)$

The line to line voltages are given by:

${V_{ab}} = {V_{an}} - {V_{bn}} = \sqrt 3 {V_m}\sin \left( {\omega t + \frac{\pi }{6}} \right)$

${V_{ba}} = {V_{bn}} - {V_{an}} = \sqrt 3 {V_m}\sin \left( {\omega t - \frac{{5\pi }}{6}} \right)$

${V_{bc}} = {V_{bn}} - {V_{cn}} = \sqrt 3 {V_m}\sin \left( {\omega t - \frac{\pi }{2}} \right)$

${V_{cb}} = {V_{cn}} - {V_{bn}} = \sqrt 3 {V_m}\sin \left( {\omega t + \frac{\pi }{2}} \right)$

${V_{ca}} = {V_{cn}} - {V_{an}} = \sqrt 3 {V_m}\sin \left( {\omega t + \frac{\pi }{2}} \right)$

${V_{ac}} = {V_{an}} - {V_{cn}} = \sqrt 3 {V_m}\sin \left( {\omega t - \frac{\pi }{6}} \right)$

previous SINGLE-PHASE CONVERTERs

next Three-phase half-wave Controlled Rectifier

Power, Electronic Systems, Applications and Resources on Electrical and Electronic Project-Thesis

THREE-PHASE CONTROLLED RECTIFIER

1 comment:

Popular Post