# IGBT Modules - Technologies, Driver and Application (Second Edition) - page 496

484
between DPWM0, DPWM1 and DPWM2 depending on the phase angle
ϕ
, one can
achieve a total minimum of switching losses for the inverter power semiconductors. In a
regionof approx. -50° to50° anSLF of below0.55 canbe provided.
13.13 Fundamental equations
Based on the general topology of a 3-phase inverter the following provides some
fundamental equations.
Fig. 13.22
Set-upwith input rectifier, DC-bus, inverter andmotor load
13.13.1 Input rectifier
For the maximum rectified voltage U
DC,max
, without consideration of the internal voltage
drop across the diodes and serial impedances, the followingapplies:
Grid ,LL
max ,DC
U2
U
=
Eq. 13.35
Each diode conducts the current for
1
/
3
of the time of a mains period, i.e. 120°. The
average current I
avg
per diode thus results from:
DC
DC
avg
I
3
1 I
360
120
I
⋅ = ⋅
°
°
=
Eq. 13.36
Whilst theRMS current I
RMS
is:
( )
DC
DC
2
Diode
RMS
I
3
1 I
360
120
dt t
i
I
= ⋅
°
°
=
=
Eq. 13.37
13.13.2 Output inverter
The electric power of the load is calculated according to
cos
ϕ
is the phase
angle between U