PGH1008AM [NIEC]
3-phase diode bridge plus thyristor; 3相二极管电桥的晶闸管加
| 型号： | PGH1008AM |
| 厂家： | 
NIHON INTER ELECTRONICS CORPORATION |
| 描述： | 3-phase diode bridge plus thyristor |
| 文件： | 总10页 (文件大小：791K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
3-phase diode bridge plus thyristor
PGH series Power Module
PGH series power module includes 3-phase
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.
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
E-36
E-15
41.5mm
97.5mm
34mm
75mm
E-43
62mm
108mm
PGH series
PGH series Packages
List of PGH series
Part Number
IT(AV), IF(AV) (A)
VDRM ,VRRM (V) Case Outline
PGH308
30
30
800
1600
800
E-15
E-36
E-36
E-36
E-36
E-36
E-36
E-36
E-43
E-43
E-43
E-43
PGH3016AM
PGH508AM
PGH5016AM
PGH758AM
PGH7516AM
PGH1008AM
PGH10016AM
PGH1508AM
PGH15016AM
PGH2008AM
PGH20016AM
50
50
1600
800
75
75
1600
800
100
100
150
150
200
200
1600
800
1600
800
1600
S. Hashizume Dec., 2007 Rev.1.0
1
AVG
Id
eRMS
eRMS
eRMS
IdAVG
IdAVG
IdAVG
eRMS
eRMS
e
Rectification circuit
RMS
eRMS
Output voltage
Average current
IdAVG
0.5 IdAVG
0.5 IdAVG
0.333 IdAVG
RMS current
Peak current
Average current
1.57 IdAVG
3.14 IdAVG
0.785 IdAVG
1.57 IdAVG
0.5 IdAVG
0.707 IdAVG
IdAVG
0.785 IdAVG
1.57 IdAVG
0.5 IdAVG
0.707 IdAVG
IdAVG
0.579 IdAVG
1.05 IdAVG
0.333 IdAVG
0.578 IdAVG
IdAVG
RMS current
Peak current
Peak reverse voltage
to Diode
1.41 eRMS
3.14
2.82 eRMS
1.41 eRMS
2.45 eRMS
DC output voltage
Peak /Average
1.57
2
1.57
1.05
1.73
AC input voltage
Line voltage/Phase
Voltage
AC input voltage
2.22
1.11
1.11
0.428
RMS / Average
Table 1 Constants of rectification circuits
Diode current
200V RMS
200V RMS
200V RMS
28.2Ω
Diode voltage
490V
An example of diode current and voltage
in three phase full-wave rectification circuit
3
follows.
For AC200V line: VDRM and VRRM : 800V
●Thyristor
1, What’s thyristor
Thyristor is considered as a diode and a switch
connected in serial.
For AC400V line: VDRM and VRRM : 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.
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 hFE
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
TDK 3-phase line filter and internal diagram
i
E
vT
iG
iC
hFE×iB
E
vCE(sat)
iB
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.
IT
e
e
Gate trigger current
Gate
current
Gate current turns on Thyristor
IT
2, Behaviors of Thyristor as a switch — Holding
current, and Latching current
2-1, Holding current
Thyristor turns off when anode current be-
comes below 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.
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 decreases.
Anode current
Thyristor
turns off.
Latching current
Thyristor turns off
because of slow rise
of anode current.
Holding current
time
Time
ON
OFF
Latching current
Holding 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℃.
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
3, Gate drive
3-1 How to achieve sure turn-on
×2
×1
3-1-1 Temperature dependence of gate char-
acteristics
In datasheet of PGH308, you will find a graph of
gate characteristics like this.
0
5µs
10µs
50µs
2µs
20µs
Pulse width
Typical pulse trigger current
DC. Assuming that the minimum operating tem-
perature is -20℃ and pulse width is 5µs, the esti-
mated peak trigger current is 300mA (150mA×
2). Accordingly, combination of dependence in
temperature and dependence in pulse width will
give you how large is the required gate current to
trigger.
This graph shows required gate current and
voltage to trigger all the PGH308 at -40℃, at 25℃
and 125℃. For example, we know that DC cur-
rent of 100mA can turn on every PGH308 at 25℃,
and accompanied gate voltage is less than 2.5V.
Based on this graph, let us find out how large is
the gate trigger current at a certain temperature,
which comes from the lowest operating tempera-
ture of the equipment in which the thyristor will be
installed. Trigger currents at -40℃, 25℃, and
3-2 Ratings of gate current, voltage, and power
Rating is the limit where stress on device may
spoil its reliability significantly or cause catastro-
phic damage. As shown on the graph below, the
three ratings - peak gate current, voltage, and
power (gate current times gate voltage) - are de-
fined. In addition, average gate power is also
limited. For detailed information, refer to indi-
vidual datasheet.
125℃ are plotted on the graph like below, and we
can estimate that trigger current at –20℃ is around
150mA.
Gate voltage : less than 10V
200mA
100mA
0
Power:Less than 5W
All triggered at-40℃
Gate current : less than 2A
0℃
50℃
150℃
-50℃
100℃
Junction temperature
Gate ratings
Temperature dependence of gate current
To turns on thyristor firmly, gate current and
gate voltage tend to become high. Be careful in
average power for DC triggering, and in peak
power for pulse triggering.
3-1-2 Pulse width dependence of gate trigger
current
In case that pulse gate current is applied, and
pulse width is shorter than 20µs, required gate
current to turn on thyristor is large compared with
DC. Furthermore, a remarkable increase in gate
trigger current is needed when the pulse duration
falls below 10 µs specifically. For example, pulse
trigger current of 5µs width is twice larger than
3-3 To avoid trigger by noise (To avoid mal-
function)
The maximum gate voltage not to trigger is
0.25V （Tj＝125℃、2/3・VDRM）. This implies that
more than 0.25V between gate and cathode may
possibly turn on the thyristor.
6
In order to avoid unintended turn-on by noise
(malfunction), such measures are expected to be
effective.
*Connect cathode of trigger signal to the terminal
ex-
nal resistance). Accordingly, considering mini-
mum operating temperature and width of trigger-
ing pulse, we can design gate driver that can turn-
on every device, where drive current, voltage, and
power are all well within the corresponding rat-
ings.
As shown in the figure below, at first, plot open-
circuit power-supply voltage of the gate trigger
circuit on the voltage axis (vertical axis), and plot
short-circuit current at the current axis (horizontal
axis). Then, link these two points by straight line.
This gate load line should exceed area that all
devices can be triggered, and should also satisfy
all the ratings - gate current, gate voltage, and gate
power. In this example, short-circuit current is
0.5A, and open voltage is 8V. Therefore, we
know that the current-limiting resistance is 16 Ω.
Terminals for trigger
clusive for trigger.
*Gate serial diode
Noise as high as diode forward voltage
(approximately 0.7 V) is cancelled. However, the
drive signal is cut by the voltage, and, if necessary,
it should be compensated..
Total16Ω
*Gate parallel diode
The diode may prevent an excessive gate reverse
voltage.
8V
*Gate parallel capacitor （0.01～0.1µF）
Design example of gate load line
The load line is a classical way of thinking. At
present, we can easily realize constant-voltage or
constant-current drivers. IGBT and MOSFET are
driven by voltage, however, thyristor is driven by
current. Consequently, when designing gate
driver for thyristor, apply constant-current basis
design.
Incidentally, reverse power loss of thyristor in-
creases significantly in case of applying DC gate
current while reverse voltage is applied to anode
to cathode. Because reverse voltage isn't applied
to PGH in standard applications, this fact is not
meaningful. However, remember that it’s an im-
portant nature of thyristor.
Measures to avoid gate malfunction
3-4 Gate load line
A gate load line is used to specify the power-
supply voltage to gate trigger circuit, and current-
limiting resistance (including power supply inter-
４, Thermal design (Choice of heatsink)
Including PGH, base plate of power module is
generally made of copper. However, unless
combined with heatsink, temperature rise is so
Gate to cathode voltage :less than 10V
Power : less than 5W
30A
Gate current:
less than 2A
All triggered consider-
ing operating tempera-
ture and pulse width
Gate load line
PGH508AM
7
and 10ms. Here, the I is RMS current. Assuming
that 1 pulse surge on-state current is 600A, I2t can
be calculated as follows.
200A at 2 µs, ･･･ after turn-on (after gate current
begins to flow). The initial turned-on area de-
pends on gate drive current. The faster and the
larger on-gate is, the larger initial turn-on area is.
For that reason, faster and larger gate current, such
as iG=200mA and , diG/dt=0.2A/µs, is specified as
standard condition for di/dt for a thyristor that has
maximum trigger gate current of 50mA at 25 °C.
When high di/dt is anticipated, additional reactor
in the anode current loop is effective to suppress
di/dt. Additionally, enough large and sharp on-
gate current within gate ratings, is also valid to
improve di/dt capability of thyristor itself.
（600／√2）2×0.01＝1,800A2s
This figure is useful when thyristor is protected
by (cutting) fuse. There is a similar regulation in
fuse, too, so we can choose a matched pair where
thyristor doesn't fail but fuse is broken.
Critical rate of rise of turn-on current di/dt de-
fines how large is the destructive limit below 2ms.
After gate current is applied, it takes about 100 µs
before all the area of thyristor turns into on-state.
In other words, if pulse width of current is very
short, partial conduction occurs. As a result,
small area owes the power, and power density in
the area also becomes very high.
It is the di/dt that, for such reason, prescribes the
rating against sharp rising current pulse.
These three current rating are represented on
common time axis as follows.
5-2 Critical rate of rise of off-state voltage dv/
dt
As explained, thyristor is normally turned on by
gate current. However, it may be also turned on
by high dv/dt of anode voltage. It is the critical
rate of rise of off-state voltage dv/dt, which pre-
scribes the limit of rising. Displacement current
into inner capacitance of thyristor chip has similar
effect to gate current.
I2t
50Hz
The dv/dt is a typical cause of thyristor mal-
functions. Thyristor chips which have dv/dt ca-
pability of 100V/µs or more have internal resis-
tance that can bypass displacement current.
Countermeasures against malfunction by dv/dt
include application of thyristor that has higher dv/
dt capability, addition of RCD to gate circuit same
as for noise, and controlling dv/dt itself by CR
snubber.
ITSM
di/dt
2ms
10ms
At present, we don’t worry whether major
power switching devices, such as MOSFET or
IGBT, would withstand starting-up current or not
even if how fast it is. This is because very small
unit-cells are accumulated in one chip, and their
high frequency characteristics are remarkably
excellent compared with thyristor. By contrast,
general thyristor is made of single thyristor unit.
Therefore, on-region begins from neighborhood
area of gate, and it spreads to the whole chip with
time.
Excessive dv/dt is
applied
Thyristor
turns on.
Gate
Cathode
On-region
spreads
with time
On-region spread of Thyristor chip
If critical rate-of-rise of on-state current di/dt is
100A/µs, for example, thyristor may fail when
anode current reaches more than 100A at 1 µs,
10
相关型号：
©2020 ICPDF网 联系我们和版权申明