11 RECTIFIER 3ph [PDF]

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Three Phase Rectifier Dr. Ir. Mochamad Ashari, M.Eng.



Dept. of Electrical Engineering Sepuluh Nopember Institute of Technology (ITS) Surabaya 1



Pendahuluan • Three-phase rectifier: ƒ 3 pulsa ƒ 6 pulsa ƒ 12 pulsa



• Three-phase rectifier: ƒ Uncontrolled ƒ Semi Controlled ƒ Fully Controlled



• Loads: ƒ Resistive ƒ RL, RC ƒ RLC Rectifier 3 phase, Dr. M.Ashari-T.Elektro-ITS



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Rectifier 3-Pulse • Uncontrolled: ƒ Menggunakan diode ƒ Tegangan output tidak dapat dikontrol Uncontrolled 3-pulse



• Fully Controlled: ƒ Menggunakan thyristor ƒ Tegangan output dapat dikontrol ƒ Pengontrolan melalui sudut penyalaan pada gate thyristor



Fully controlled 3-pulse Rectifier 3 phase, Dr. M.Ashari-T.Elektro-ITS



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Fully Controlled 3-Pulse Beban R • Performance Parameters: ƒ Tegangan dan arus rata-rata ƒ Tegangan dan arus rms ƒ Ripple ƒ Harmonisa: • Tegangan output • Arus input • α= sudut penyalaan • β= sudut pemadaman



Rectifier 3 phase, Dr. M.Ashari-T.Elektro-ITS



α



β 4



2



Mode Operasi ωt = 30o



ωt = 150o



•Untuk α=0o berarti ωt= 30o •Range sudut penyalaan : 0o ≤ α ≤ 150o atau 30o ≤ ωt ≤ 180o •Continuous Conduction Mode (CCM)



: 0o ≤ α ≤ 30o



•Discontinuous Conduction Mode (DCM): 30o ≤ α ≤ 150o Rectifier 3 phase, Dr. M.Ashari-T.Elektro-ITS



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Continuous Conduction Mode (CCM)



α = 15o ωt = 30o + 15o



β = 150o + α



•Range: 0o ≤ α ≤ 30o atau 30o ≤ ωt ≤ 60o •Sudut pemadaman β= 150o + α •Arus sesaat tidak pernah bernilai nol Rectifier 3 phase, Dr. M.Ashari-T.Elektro-ITS



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Tegangan rata-rata CCM Vm= amplitudo teg. line-to-neutral 0o ≤ α ≤ π/6



V ave



1 = T



T



∫ 0



3 fθ d θ = 2π



5π +α 6



∫V π 6



I ave =



m



sin ω td ω t =



+α



3 3V m cos α 2π



Vave R



Rectifier 3 phase, Dr. M.Ashari-T.Elektro-ITS



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Tegangan rms CCM Vm= amplitudo teg. line-to-neutral 0o ≤ α ≤ π/6



V rms =



1 T



T



∫ (V



sin ω t ) d ω t = 2



m



0



3 2π



5π +α 6



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1 2 3 V sin ω td ω t = 3Vm  + cos 2α  ∫ π  6 8π  +α 2 m



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I rms =



Vrms R



Pdc = Vave I ave = Pac = Vrms I rms =



2 Vave R 2 rms



V R



η=



Rectifier 3 phase, Dr. M.Ashari-T.Elektro-ITS



Pdc Pac 8



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Discontinuous Conduction Mode (DCM) α = 60o ωt = 30o + 60o



β =π •Range: 30o ≤ α ≤ 150o atau 60o ≤ ωt ≤ 180o •Sudut pemadaman β = π •Arus sesaat bernilai nol untuk suatu periode waktu Rectifier 3 phase, Dr. M.Ashari-T.Elektro-ITS



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Tegangan Output DCM Vm= amplitudo teg. line-to-neutral π/6 ≤ α ≤ 5π/6



V ave =



1 T



T



∫



fθ d θ =



0



π



3 2π



∫V π 6



V rms =



1 T



T



∫ (V



m



sin ω td ω t =



+α



3 2π



sin ω t ) d ω t = 2



m



0



π



∫V π 6



=



2 m



[



(



3V m 1 + cos α + 30 o 2π



)]



sin 2 ω td ω t



+α



1



α 1  5 2 3V m  − + sin 60 o + 2α  24 4 π 8 π  



Rectifier 3 phase, Dr. M.Ashari-T.Elektro-ITS



(



)



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Arus Input Rectifier • Arus input muncul hanya setengah gelombang perfase • Arus input selalu discontinuous • Harmonisa cukup besar



Rectifier 3 phase, Dr. M.Ashari-T.Elektro-ITS



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Beban RL Tanpa Free-wheeling Diode • Tanpa Free-wheeling Diode: β



Rectifier 3 phase, Dr. M.Ashari-T.Elektro-ITS



ƒ Thyristor dipaksa untuk tetap ‘on’ sampai energi induktor habis ƒ β>π , besar β tergantung pada rasio ωL/R ƒ Tegangan output sesaat dapat berharga negatif



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Beban RL Dengan Free-wheeling Diode • Dengan free-wheeling diode: β



ƒ Energi induktor dilepas melalui free-wheeling diode ƒ β=π ƒ Tegangan output sesaat selalu positif



Rectifier 3 phase, Dr. M.Ashari-T.Elektro-ITS



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Rectifier 6-Pulse • Uncontrolled: ƒ Menggunakan 6 diode ƒ Tegangan output tidak dapat dikontrol



Uncontrolled 6-pulse



• Semicontrolled: ƒ Menggunakan 3 thyristor dan 3 diode ƒ Tegangan output dapat dikontrol



• Fully Controlled: ƒ Menggunakan 6 thyristor ƒ Tegangan output dapat dikontrol Rectifier 3 phase, Dr. M.Ashari-T.Elektro-ITS



Semi controlled 6-pulse



Fully controlled 6-pulse



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Rangkaian Eqivalen



Vfase = 100/√3 volts rms



Vline = 100 volts rms Rectifier 3 phase, Dr. M.Ashari-T.Elektro-ITS



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Firing Angle 0 Degree



Rectifier 3 phase, Dr. M.Ashari-T.Elektro-ITS



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Firing Angle 30 Degrees



Rectifier 3 phase, Dr. M.Ashari-T.Elektro-ITS



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Firing Angle 60 Degrees



Rectifier 3 phase, Dr. M.Ashari-T.Elektro-ITS



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Fully Controlled 6-Pulse • CCM



0 o ≤ α ≤ 60o



V ave =



3 3V m



π



cos α



• DCM



60o ≤ α ≤ 150o



V ave =



 3 3V m  cos α 3 − sin α  1 + π 2 2  



Rectifier 3 phase, Dr. M.Ashari-T.Elektro-ITS



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Rectifier 12-Pulse + y Y



Vdc



∆



+



-



Rectifier 3 phase, Dr. M.Ashari-T.Elektro-ITS



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Sirkuit Simulasi



Rectifier 3 phase, Dr. M.Ashari-T.Elektro-ITS



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Tegangan Output



Rectifier 3 phase, Dr. M.Ashari-T.Elektro-ITS



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Arus Input



Rectifier 3 phase, Dr. M.Ashari-T.Elektro-ITS



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