• Author / Uploaded
• GomDorji

Citation preview

Three phase inverters in o 180 conduction mode with the delta connected Load Presented by:- Gom Dorji Tenzin Dorji Tshering Choden Ugyen Wangchuk

Delta connected load

VR= VS (T1ON) VR= -VS(T4ON)

VY= VS (T5ON) VY= -VS(T2ON)

VB= VS (T3ON) VB= -VS (T6ON)

Load R=R1=R2

• Each thyristor conducts for 180 degrees. • There are VI mode of operations in a complete time period with the duration of 60 degrees in a sequence. • Three thyristors conduct at any instant of time (two in one half and one in other) • For delta connected line voltage is equal to phase voltage. • From phase voltage phase current can be determined.

Input waveforms for 180 Conductions

T1 T5 T6

T1 T2 T6

T1 T2 T3

T2 T3 T4

T3 T4 T5

T4 T5 T6

T1 T5 T6

Mode 1 operations SCR T1ON, T5ON, T6ON

 0  t  3 For Delta connected VL=Vph, IL=√3Iph Output voltages VR= VRY=0 VY= VYB=Vs VB=VBR= -Vs

Output currents IR= √3IRY= 0 IY= √3IYB= √3Vs/R IB= √3IBR= -√3VS/R

Mode 2 operations SCR T1ON, T2ON, T6ON



2  t  3 3

Output voltages VR= VRY=Vs VY= VYB=0 VB=VBR= -Vs Output currents IR= √3IRY= √3Vs/R IY= √3IYB= 0 IB= √3IBR= -√3VS/R

Mode 3 operations SCR T1ON, T2ON, T3ON

2  t   3

Output voltages VR= VRY=Vs VY= VYB=-Vs VB=VBR= 0 Output currents IR= √3IRY= √3Vs/R IY= √3IYB= -√3VS/R IB= √3IBR= 0

Mode 4 operations SCR T2ON, T3ON, T4ON

𝜋 ≤ 𝜔𝑡 ≤ 4𝜋/3 Output voltages VR= VRY=0 VY= VYB=-Vs VB=VBR= Vs Output currents IR= √3IRY=0 IY= -√3IYB= -√3VS/R IB= √3IBR= √3Vs/R

Mode 5 operations SCR T3ON, T4ON, T5ON

4𝜋/3 ≤ 𝜔𝑡 ≤ 5𝜋/3

Output voltages VR= VRY=-Vs VY= VYB=0 VB=VBR= Vs Output currents IR= √3IRY=−√3VS/R IY= √3IYB= 0 IB= √3IBR= √3Vs/R

Mode 6 operations SCR T4ON, T5ON, T6ON

5𝜋/3 ≤ 𝜔𝑡 ≤ 2𝜋

Output voltages VR= VRY=-Vs VY= VYB= Vs VB=VBR= 0 Output currents IR= √3IRY=−√3VS/R IY= √3IYB= √3Vs/R IB= √3IBR= 0

Parameters Mode 1 Mode 2 Mode 3

Mode 4 Mode 5 Mode 6

VR=VRY

0

VS

VS

0

-VS

-VS

VY=VYB

VS

0

-VS

-VS

0

VS

VB=VBR

-VS

-VS

0

VS

VS

0

IRY

0

VS/R

VS/R

0

-VS/R

-VS/R

IYB

VS/R

0

-VS/R

-VS/R

0

VS/R

IBR

-VS/R

-VS/R

0

VS/R

VS/R

0

IR

0

√3Vs/R

√3Vs/R

0

-√3Vs/R -√3Vs/R

Iy

√3Vs/R

0

-√3Vs/R

-√3Vs/R 0

√3Vs/R

IB

-√3Vs/R -√3Vs/R 0

√3Vs/R √3Vs/R

0

IPHASE

ILINE

Voltage waveform

Current waveform

Mathematical expression The instantaneous line to line voltage VRY in fourier series can be express as:

VRY =

From the output voltage waveform ao and an =0

Therefore line voltage VRY is, VRY

VRY

VYB =

VBR =

Thank You Any Question???