IEEE Power Electronics Magazine - September 2020 - 49

40

1.5 Ω

SiC

Turn Off dv/dt (kV/µ s)

35

Si

30
5Ω

25
20

16 Ω

10

30 Ω

5
0

0

10

Peak Reverse Recovery dv/dt [kV/µs]

50

1.5 Ω

45

0Ω
5Ω

SiC

35
30

3Ω

25
20

0Ω

15
10

7.5 Ω
10 Ω 16 Ω

5
0

0

7.5 Ω 10 Ω

16 Ω
300

FIG 13 RG Turn-on controllability Ic/ID=300 A, 125 °C, VGE=+15 V/
-12 V, 1000 Vdc, Inductive load; Peak dv/dt was measured at
0 A for Si and 300 A for SiC.

300
250
200
150
SiC

100

0

10

20
30
40
Carrier Frequency (kHz)

Si

50

Conditions:
3φ Sinusoidal Modulation,
1,000 Vdc, PF = 0.9, M = 1,
Tsink = 80 °C, RG(Si) = 0 Ω,
RGON(SiC) = 3.4 Ω,
RGOFF(SiC) = 10 Ω

16 Ω

FIG 12 RG Turn-off controllability Ic/ID = 300 A, 125 °C,
VGE = +15 V/−12 V, 1000 Vdc, Inductive load.

3.4 Ω

50
100
150
200
250
Turn On Switching Loss at 300 A (mJ)

10 Ω

20 30 40 50 60 70 80
Turn Off Switching Loss (Eoff) [mJ]

Si

40

50

10 Ω

15

to 50 kHz. The plot represents the maximum output current
capability allowed versus fc until T j reaches 150 °C maximum. At all carrier frequencies, the SiC module provides
greater output current capability. At 10 kHz, the Si module
can support up to 175 A rms while the SiC module is capable
of 275 A rms, a 57% increase. At 160 A rms the Si module is
capable of a carrier frequency up to 11 kHz while the SiC
module is capable of 50 kHz, 4.5 times higher fc .
Figure 15 shows the total power module losses versus carrier frequency at a set sinusoidal output current of
200 A rms . The other simulation conditions are the same as

Maximum Output Current (Arms)

SiC modules. The maximum turn-off dv/dt and turn-off
switching energy were recorded at rated current of 300 A.
As shown in Figure 12, the SiC module has a larger range
of controllability with a possibility of 90% lower E off . When
the Si and SiC module turn-off dv/dt are both adjusted to
8 kV/ns, the SiC module is still capable of 45% lower E off .
The maximum reverse recovery dv/dt and turn-on switching energy were also recorded at various gate resistance
values. As shown in Figure 13, the SiC module has a larger
range of controllability with a possibility of 81% lower E on .
When the Si and SiC module reverse recovery dv/dt are both
adjusted to 10 kV/ns, the SiC module is still capable of 54%
lower E on . Additionally, the SiC module has approximately
96% lower E rr as shown in Figure 10 which further contributes to reduced power losses in the module.
During development, the designer must consider the
EMI noise generated from dv/dt, di/dt, and ringing of the
voltage/current waveforms at switching. EMI/ringing can
be reduced by switching slower (increasing Rg) but that will
cause increased switching losses. Therefore, the designer
must determine the acceptable trade-off between switching losses and EMI for their specific application.
Simulations: Using the data measured above, loss/
temperature simulations were performed to characterize
each modules performance. The simulations below are for
a 3-phase inverter using conventional sinusoidal modulation with a modulation ratio of 1. A dc bus voltage of 1000 V
was selected which is typical for 1700 V rated power modules. A fixed heatsink temperature of 80 °C was selected
which is typical for air-cooled heatsink applications. The
output power factor was selected to be 0.9. Additionally,
gate resistance values of R G (Si) = 0 X, R Gon (SiC) = 3.4 X,
R Goff (SiC) = 10 X were selected after considering the tradeoffs between switching losses, dv/dt, and surge voltage.
The Figure 14 simulation results show the overall module output current capability at carrier frequencies (fc) up

90

FIG 14 Maximum current capability (limited by Tj =150 °C
maximum).

September 2020

z	IEEE POWER ELECTRONICS MAGAZINE

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IEEE Power Electronics Magazine - September 2020

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