PWM Inverters
Single-Phase Half-Bridge
(2)
Vh = (Vo2-V12)1/2
PWM Inverters
Single-Phase, Full-Bridge
Q3Q4
Vs -Vs
Vh = (Vo2-V12)1/2
Delta-Connected Load
Vab Vs
0 ωt
π
2π
π
2π
π
2π
-Vs
561 612 123 234 345 456
Vbc Vs
a aa aa a V VVsss VsVs Vs c
b bb bb b
612 561 123 345 234 456
0 ωt cc cc c
-Vs Vca Vs
Three transistors remain ON for any instant of time.
0 ωt
Star-Connected Load
561 612 123 234 345 456
Three transistors remain ON for any instant of time.
561 ab 612 123 aa 234 345 456 c ba c bc VVs s cb nV b s a Vs V ns b Vs c a c
nn
n n
Star-Connected Load
Van Vs/2
0 ωt
g1 g2 g3 g4 g5 g6
61 12
23 34
45
π
2π
π
2π
π
2π
-Vs/2
56 VVs s V s V s nn Vs nn n Vs
In 61 45 12 23 34 delta56 connected load, the potential of the open terminal is unpredictable.
aa aa aa bb bb bb cc c cc c
ωt ωt n ωt
Vbn Vs/2
0 ωt
ωt
-Vs/2
ωt
Vcn Vs/2
ωt
Two transistors remain ON for any instant of time.
0 ωt
456
a b
n Vs c 561
a c
Vs
561 612 123 234 345 456
561 612 123 234 345 456
b
n
Simulink
Q1: ON Q4: OFF
Q1: OFF Q4: ON
Phase Voltages
Line Voltages