IEEE Power Electronics Magazine - September 2019 - 29

LV Side

MV Side
MV Grid
LCL
(4,160-V L-L) Filter

LCL
Filter

9:È3

LV Grid
(480-V L-L)

FIG 15 The schematic of an MV-SST. The LV gate driver enables the operation of the LV side inverters [18]. L-L: line to line.

Applications of SiC MOSFETs Using the
Designed Gate Drivers
The design of the gate drivers must be validated through
experiments in continuous mode of operation to affirm its
reliable operation. Applications concerning a two-level
three-phase inverter and a dc-dc boost converter using the
eight-channel gate driver are shown. A photo of the two-level
three-phase inverter used for the test is shown in Figure
12(a). Initially, the gate driver is tested with 1,200-V 100-A
SiC MOSFETs. The converter operation result at 25 kW for a
dc-link voltage of 800-V is provided in Figure 12(b).
The gate driver is, therefore, tested with 1,700-V SiC
MOSFETs to ensure proper operation at a higher operating voltage, and the test results for a dc-dc boost converter
operation are shown in Figure 12(c). This eight-channel gate
driver board is also tested for enabling series connections
of LV SiC MOSFETs to achieve higher voltage operation, as
shown in [14] and [16]. This is illustrated in Figure 13, where
a dc-dc converter operation with four series-connected
1,700-V SiC MOSFETs is operated at a dc-link voltage of
3,000 V with a load of 100 kW. The voltage measurements
are carried out using a Tektronix P6015A (20-kV dc, 75 MHz)
probe, and the current measurements are carried out by
Tektronix TCT303, which has a bandwidth of 15 MHz.
The use of a single gate driver board for these applications enables a standardization of the gate driver board
for a wide variety of applications and devices. It should be
noted that minor changes must be carried out on the gate
driver while operating SiC MOSFETs at different voltage
and current levels. The rating of the isolated power supply
is determined by the gate charge of the SiC MOSFETs and
their operating frequencies. In addition, the power rating
of the gate resistance also changes with a change in the
gate charge.

Heat Sink
(Condenser)
GDPS
Gate Drivers
Decoupling
Capacitors

Heat Sink
(Evaporator)

Current
Sensor

Voltage
Sensor

(a)

Ch1: 500 V/div

Ch2: 150 A /div

Ch3: 150 A /div

Efficiency (%)

This helps with reshaping the voltage waveform and thus
reduces switching losses. Figure 11(c) shows the experimental tests for verifying optical measurements from the
IGD and the desat functionality of the gate driver. A halfbridge circuit with a dc-link voltage of 60 V is used for the
test. The desat setting allows up to 9-A current for this
device under test. The desat-sensing, on-state voltage, module temperature, and drain-current measurements are verified in this test.

99.78
99.77
99.76
99.75
99.74
99.73
99.72
99.71
99.7
99.69
99.68
90

100

Ch4: 150 A /div Time: 5 ms/div
(b)

110 120 130 140
Peak Line Current (A)
(c)

150

160

FIG 16 (a) A photo of the 100-kVA power block with a 1,200-V,
325-A SiC-MOSFET-based half-bridge module [17]. (b) The validation of a three-phase two-level grid-connected system with a
dc-link voltage of 800 V and a peak inverter current of 150 A.
Ch1: pole-to-pole voltage; Ch2: current through the R-phase;
Ch3: current through the Y-phase; Ch4: current through the
B-phase. (c) The efficiency of the LV power block as a function
of the peak line current.

September 2019

z IEEE POWER ELECTRONICS MAGAZINE

IEEE Power Electronics Magazine - September 2019

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