3-phase diode bridge
plus
thyristor
PGH series Power Module
PGH series power module includes 3-phase
diode bridge and inrush current limiting thyristor
in a package. This series are widely applied to
rectification circuit in popular 3-phase inverters.
This paper shows how to use PGH series, and also
covers information on 3-phase rectification cir-
cuit, driver circuit, and selection of heatsink. In
addition, it provides designers, who are not very
familiar with thyristor, with its basic application
information.
E-36
E-15
34
mm
75
mm
41.5
mm
97.5
mm
E-43
62
mm
108
mm
PGH series
PGH series Packages
List of PGH series
Part Number
PGH308
PGH3016AM
PGH508AM
PGH5016AM
PGH758AM
PGH7516AM
PGH1008AM
PGH10016AM
PGH1508AM
PGH15016AM
PGH2008AM
PGH20016AM
I
T(AV)
, I
F(AV)
(A)
30
30
50
50
75
75
100
100
150
150
200
200
V
DRM
,V
RRM
(V)
800
1600
800
1600
800
1600
800
1600
800
1600
800
1600
Case Outline
E-15
E-36
E-36
E-36
E-36
E-36
E-36
E-36
E-43
E-43
E-43
E-43
1
S. Hashizume Dec., 2007 Rev.1.0
follows.
For AC200V line : V
DRM
and V
RRM
: 800V
For AC400V line : V
DRM
and V
RRM
: 1,600V
Between AC line and bridge rectifier, use appro-
priate AC line filter. It reduces the noise entering
into the equipment not so as to cause any unde-
sired behaviors. Furthermore, it suppresses con-
ducted emission from the equipment. As are ex-
pected, external stresses on diode and thyristor,
such as surge voltage and current, can be de-
creased by such filter.
●Thyristor
1, What’s thyristor
Thyristor is considered as a diode and a switch
connected in serial.
Anode
Cathode
Gate
Thyristor
Same as bipolar transistor, thyristor is driven by
current. With respect to bipolar transistor, when
base current is applied, collector current of h
FE
times base current flows. In contrast, thyristor is
switched on by gate current that is higher than a
specific value (gate trigger current). The follow-
ing figure illustrates these relationships. You will
see that collector current of bipolar transistor
flows during the whole period when base current
flows, but thyristor keeps anode current flowing
even after the gate current is cut off. So, you need
not supply thyristor with continuous gate current
i
TDK 3-phase line filter and internal diagram
Thyristor (SCR)
Anode
E
i
E
v
T
v
i
G
i
G
Gate
Cathode
Bipolar transistor (NPN)
Collector
E
i
C
E
i
C
h
FE
×i
B
v
CE(sat)
v
CE
i
B
i
B
Base
Emitter
4
during all of the on-period. At present, major
switching devices, such as MOSFET and IGBT,
are driven by voltage, but thyristor is current-
driven device. Please keep in mind this fact when
you design gate firing circuit for thyristor.
I
T
e
Gate trigger current
e
Gate
current
Gate current turns on Thyristor
2, Behaviors of Thyristor as a switch
—
Holding
current, and Latching current
2-1, Holding current
Once thyristor turns on, the on-state is main-
tained as far as anode current is larger than a cer-
tain value. In other words, thyristor turns off
when anode current decreases to a certain value.
The “certain current” is the holding current, and
that of PGH308 (30A 800V) is 70mA typical at
25℃.
(Refer
to individual datasheet.) Now, let's
see the influence of holding current in an actual
circuit.
Anode current decreases.
I
T
Thyristor turns off when anode current be-
comes below holding current.
minimum anode current which can maintain on-
state is the latching current. For example, typical
latching current of PGH308 (30A 800V) is 90mA
（25℃).
Pulse gate current
Time
Anode current
Latching current
Thyristor turns off
because of slow rise
of anode current.
Holding current
Thyristor
turns off.
Time
time
ON
OFF
Latching current
If thyristor cannot be turned on or on-state may
not be able to maintain, increase gate pulse width
or try multiple gate pulses. Both holding current
and latching current are temperature-dependent,
and they become larger at low temperature.
Compared with at 25℃, they are about twice lar-
ger at –40℃.
Holding current
Supposing that pulse trigger current is applied
only once. Thyristor is turned on, however, if the
load is resistive and anode-cathode voltage goes to
zero, anode current altogether decreases to below
holding current. After that, positive voltage
would be applied to anode, however, thyristor
maintains off-state so far as gate current would be
applied again.
2-2. Latching current
Assume that, due to slow rise of anode current,
the current doesn’t reach a certain level before
gate current is terminated, thyristor turns off. It
follows that, after removal of gate current, the
5
Analog electronics
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