Three phase delta connected inverter

Three phase inverters in 180o conduction mode with the delta connected Load

Presented by:- Gom DorjiTenzin Dorji

Tshering ChodenUgyen Wangchuk

VR= VS (T1ON)

VR= -VS(T4ON)

VY= VS (T5ON)

VY= -VS(T2ON)

VB= VS (T3ON)

VB= -VS (T6ON)

Delta connected load

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 operationsSCR T1ON, T5ON, T6ON

03

t

For Delta connectedVL=Vph, IL=3Iph

Output voltagesVR= VRY=0VY= VYB=Vs VB=VBR= -Vs

Output currentsIR= 3IRY= 0 IY= 3IYB= 3Vs/R IB= 3IBR= -3VS/R

Mode 2 operationsSCR T1ON, T2ON, T6ON

2

3 3t

Output voltagesVR= VRY=Vs VY= VYB=0VB=VBR= -Vs

Output currentsIR= 3IRY= 3Vs/RIY= 3IYB= 0IB= 3IBR= -3VS/R

2

3t

Mode 3 operationsSCR T1ON, T2ON, T3ON

Output voltagesVR= VRY=Vs VY= VYB=-Vs VB=VBR= 0

Output currentsIR= 3IRY= 3Vs/R IY= 3IYB= -3VS/R IB= 3IBR= 0

Mode 4 operationsSCR T2ON, T3ON, T4ON 𝜋≤𝜔𝑡≤4𝜋 /3

Output voltagesVR= VRY=0 VY= VYB=-Vs VB=VBR= Vs Output currentsIR= 3IRY=0 IY= -3IYB= -3VS/R IB= 3IBR= 3Vs/R

Mode 5 operationsSCR T3ON, T4ON, T5ON

4𝜋 /3≤𝜔𝑡≤5𝜋 /3

Output voltagesVR= VRY=-Vs VY= VYB=0 VB=VBR= Vs

Output currentsIR= 3IRY=3VS/R IY= 3IYB= 0 IB= 3IBR= 3Vs/R

Mode 6 operationsSCR T4ON, T5ON, T6ON

5𝜋 /3≤𝜔𝑡≤2𝜋

Output voltagesVR= VRY=-Vs VY= VYB= Vs VB=VBR= 0Output currentsIR= 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

IPHASE

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

ILINE

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

Voltage waveform

Current waveform

Mathematical expressionThe instantaneous line to line voltage in fourier series can

be express as:

From the output voltage waveform ao and an =0

VRY =

VRY

VYB =

VRY

Therefore line voltage is,VRY

VBR =

VRY

Thank You Any

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