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

Voltage source PWM inverter for PMSM supply
The total compensation time to compensate the non-linearity of inverter can be
calculated as:
U
T = T + T − T + T
(3.4)
dp
comp d ON OFF s
U
DC
Where Udp = VD −ton ( VD − VT )/ Ts
and t on
is conducting time of IGBT devices in one
sampling time.
The compensation voltage vector can be obtained as:
Tcomp
Ucomp = 2 UDC s ign( Is ) = 2Uth s ign( Is
)
(3.5)
Ts
where
and
2
2
sign( Is) = ( sign( IsA) + asign( IsB) + a sign( IsC))
,
3
⎧ sign( IsA) = 1 if IsA
> 0
sign( IsA)
= ⎨
⎩sign( IsA) = 0 if IsA
< 0
(3.6)
The sign function for remain phase currents are calculated similarly.
Solving equations (3.5) for real and imagine part in stationary frame, one obtains:
1
U U sign I sign I sign I
3
α _ comp
= 2
th
(2 (
sA) −0.5 (
sB
) − 0.5 (
sC
)) (3.7a)
1
U U sign I sign I
3
β _ comp
= 2
th
( (
sB
) − (
sC
))
(3.7b)
The waveform of compensation voltages in stationary frame are shown in Fig. 3.15.
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