Page 118 - Servo Motors and Industrial Control Theory -

112 6 AC Servo Motors

R

T
O

S
V AS

Vd
ωt

V AO

2 1 Vd
3 Vd 3 ωt

Fig. 6.10 The resulting waveform of Fig. 6.9

VARIABLE DC VOLTAGE
U
R PHASE FILTER INVERTOR
CONTROLLED V
S OUTPUT
RECTIFIER W VOLTAGE
T WAVEFORM
a PAW DRIVE
CONSTANT DC VOLTAGE
R
FULL U
FILTER INVERTOR
S BRIDGE V
W OUTPUT
T RECTIFIER VOLTAGE
WAVEFORM
b PWM DRIVE
VARIABLE DC VOLTAGE
U
R FILTER WITH
PHASE V
INVERTOR
S CONTROLLED LARGE W OUTPUT
T RECTIFIER INDUCTANCE VOLTAGE
WAVEFORM
c CSI DRIVE
Fig. 6.11 Three mostly used frequency converters in AC servo motor applications