Direct Torque Control with Space Vector Modulation (DTC-SVM) of ...

Voltage source PWM inverter for PMSM supply
Zero Sequence Signal Time interval of zero vectors Remark
SPWM
ZSS =0
for even sectors
4
t0
= (1 − ( M cos θ )) / 2
π
for odd sectors
4
t0 = t07
−(1 −( M cos θ )) / 2
π
and t7 = t07 − t0
U
DC
/2 π
M = = = 0.785
2U
DC 4
π
complicated calculation
for time interval of
vectors
THIPWM
ZSS =sinusoidal signal
with triple harmonic
for even sectors
4 1
t0
= (1 −( M cos θ) − cos 3 θ)) / 2
π 6
for odd sectors
4 1
t0 = t07
−(1 −( M cos θ) − cos 3 θ)) / 2
π 6
and t7 = t07 − t0
U
DC
/ 3 π
M = = = 0.907
2U
DC 2 3
π
Increase the linearity of
inverter grater than 15%
of SPWM
SVPWM
ZSS=triangle signal
with triple harmonic
0.906
for all sectors
M =
t = t t t /2
time interval
7 07 0 07 t = t /2
0 07 Simple calculation for
k=0.5
Table 3.1. Variants of three-phase space vector modulation techniques.
a) b)
c)
the portioning
factor of zero vectors
Fig. 3.19 PWM techniques with various zero signal sequence shape: a) SPWM, b) THIPWM,
c) SVPWM. The upper part of figure: phase voltage U
AN
(green), pole voltage U
AO
(blue),
voltage between neutral points U
NO
(black). The lower part of figure shows the portioning
factor of zero vectors for all PWM techniques.
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