This document discusses the 180 degree conduction mode of a 3 phase inverter. It operates by having three transistors conducting at a time over three modes as the phase shifts 60 degrees each time. Tables and equations are provided showing the transistors conducting, equivalent resistances, phase voltages and currents for each of the three operating modes.

1. 1800 conduction mode of
3 phase inverter
Manikandan.S
M.Tech Power System

4. 180° Conduction
• Three transistors ON at a time

5. Summary Table

6. Waveforms for 180° Conduction

7. Phase Voltages for 180° Conduction

8. Waveforms for 180° Conduction

9. Summary Table

10. Mode 1 Operation

11. Mode 1 Operation
π
0 ≤ ωt ≤
3
R 3R
Req = R + =
2
2
Vs
2Vs
i1 =
=
Req
3R
Q1, Q5, Q6 conduct
i1 R Vs
van = vcn =
=
2
3
−2Vs
vbn = −i1 R =
3

12. Summary Table

13. Mode 2 Operation

14. Mode 2 Operation
π
2π
≤ ωt ≤
3
3
R 3R
Req = R + =
2
2
Vs
2Vs
i2 =
=
Req
3R
Q1, Q2, Q6 conduct
2Vs
van = i2 R =
3
−i2 R −Vs
vbn = vcn =
=
2
3

15. Summary Table

16. Mode 3 Operation

17. Mode 3 Operation
2π
≤ ωt ≤ π
3
R 3R
Req = R + =
2
2
Vs
2Vs
i3 =
=
Req
3R
Q1, Q2, Q3 conduct
i3
van = vbn =
2
−2Vs
vcn = i3 R =
3

18. Phase Voltages for 180° Conduction