IGBT Module Series for Advanced-NPC Circuits
Kosuke Komatsu † Takahito Harada † Yoshiyuki Kusunoki †
A series of insulated gate bipolar transistor (IGBT) modules has been developed to enable advanced neutral-
point-clamped (A-NPC) inverters. Modules in this series integrate A-NPC circuits for three phases with thermistors in
a single package. Loss is minimized by the adoption of 6th-generation IGBT, free wheeling diode (FWD) and reverse
blocking IGBT (RB-IGBT) devices. Power dissipation is reduced by 51% compared to conventional two-level invert-
ers and by 33% compared to conventional NPC three-level inverters. Two types of pin conﬁguration are available,
and selectable according to customer requirements.
In recent years, initiatives to reduce CO2 emissions
in order to protect the environment have been imple-
mented in countries throughout the world. The shift to
clean energy, such as to wind power and solar power,
which does not rely on conventional fossil fuels, is be-
coming increasingly prominent.
The use of power electronics devices to conserve
energy can be found in a wide variety of applications,
from consumer electronics to electric railways, FA sys-
tems and the like. Moreover, power electronics are
used not only in power-consuming applications, but
their use has also spread to the ﬁelds of power gen-
eration, transmission and supply such as in uninter-
ruptible power supplies (UPS), wind power generators
and solar power generators. In particular, multi-level
inverters have been proposed as an efﬁcient way to
increase the power conversion efﬁciency of a UPS or
power generation system(1), and neutral-point-clamped
(NPC) inverters have been put into practical use. A
3-level inverter*1 having a simpler circuit conﬁguration
than this NPC inverter has also been proposed, but
when conﬁgured with typical insulated gate bipolar
transistor (IGBT) and diode, an increase in conduction
loss and a high surge voltage due to the wiring induc-
tance were problems.
Fuji Electric has developed circuit systems for in-
verters and converters, which are power electronics
devices, and has contributed to energy conservation
mainly in devices in the industrial ﬁeld. Additionally,
by adopting a custom low inductance package using
*1: 3-level inverter technology; See supplemental explana-
tion 1 on page 87.
† Fuji Electric Co., Ltd.
a reverse-blocking IGBT(2) (RB-IGBT), a proprietarily
developed power semiconductor, Fuji Electric has de-
veloped an IGBT module for use in advanced NPC
(A-NPC) circuits that solves the aforementioned prob-
lems(3). A UPS that utilizes this module has been in-
troduced to the market.
Presently, Fuji Electric is aiming to expand its
series of IGBT module for A-NPC circuits, and is de-
veloping an IGBT module for A-NPC circuits that in-
tegrates a three-phase A-NPC 3-level inverter circuit
and a thermistor into a single package. This paper
presents an overview of these efforts.
2. Characteristics of IGBT Modules for Advanced
An overview of the ratings, dimensions and the
like of Fuji Electric’s IGBT module series for A-NPC
circuits is shown in Table 1. The rated voltage of the
main switches is 1,200 V, the rated voltage of the inter-
mediate bidirectional switches is 600 V, and the rated
current is 100 A. The modules have the following char-
(a) Integration of a 3-phase A-NPC circuit and a
thermistor into a single package
(b) Selectable pin shape according to the inverter
Figure 1(a) shows the appearance and Fig. 1(b)
shows the equivalent circuit of the IGBT modules.
2.2 Electrical characteristics of the device
(1) Main switches
For the main switches T1 and T2 (see Table 2), the
new “V Series” IGBT and free wheeling diode (FWD)
having a rated voltage of 1,200 V were used. The V
Series has the following characteristics.