Miscellaneous active electrical nonlinear devices – circuits – and – Signal converting – shaping – or generating – Current driver
Reexamination Certificate
2001-11-14
2003-04-01
Tran, Toan (Department: 2816)
Miscellaneous active electrical nonlinear devices, circuits, and
Signal converting, shaping, or generating
Current driver
C327S432000, C327S434000, C327S310000, C327S379000, C327S389000
Reexamination Certificate
active
06542012
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a circuit for driving a gate of an insulated gate bipolar transistor (hereinafter abbreviated IGBT) inverter, and more particularly, to a single power gate driving circuit in an IGBT inverter which enables to drive a gate at a long distance by removing a noise generated as a gate driving distance gets long.
2. Background of the Related Art
FIG. 1
illustrates an equivalent circuit of a general IGBT device. In a single power driving method, a positive voltage or a zero voltage is applied to an IGBT inverter. But, in a dual power driving method, a positive voltage or a zero voltage, or a negative voltage is applied to an IGBT device.
When a DC voltage is applied across gate and emitter in the single power driving method, collector and emitter are electrically connected each other. When a zero voltage is applied between gate and emitter, collector and emitter are electrically disconnected. In other words, the IGBT device carries out a switching operation in accordance with a gate-applied voltage. In this case, ‘Cce’, ‘Ccg’, and ‘Cge’ indicate equivalent capacitances existing minutely between the respective terminals (collector-emitter, collector-gate, and gate-emitter).
Generally, the dual power driving method is used for a DC power source for driving a gate of the IGBT inverter. Yet, the dual power driving method fails to simplify the relatively complicated circuit construction, reduce the size of the inverter, and decrease the species of the voltages to reduce a cost. Accordingly, the single power driving method using the positive or zero voltage is commercialized.
FIG. 2
illustrates a general switching device using IGBT.
Referring to
FIG. 2
, a switching device using IGBT includes a first IGBT
1
of which collector is connected to a DC voltage Vdc and a second IGBT
2
of which collector is connected to an emitter of the first IGBT
1
and of which emitter is connected to a ground GND. When DC driving signals
3
and
4
having polarities opposite to each other are applied to gates of the first or second IGBTs
1
and
2
respectively, an output signal Vout is outputted from a connection point between the first and second IGBTs
1
and
2
. In this case, the circuit shown in
FIG. 2
represents an inverter circuit in part.
The switching device using the above-constructed IGBTs carries out ‘ON’ and ‘OFF’ of the first and second IGBTs
1
and
2
by the DC driving signals applied to the gates of the first and second IGBTs
1
and
2
so as to output the output signal Vout having the DC voltage Vdc or a voltage of the ground GND.
The above operational control is explained in detail as follows.
First, when the first IGBT
1
turns ‘ON’ and the second IGBT
2
turns ‘OFF’ by the DC driving signals
3
and
4
, the output signal Vout becomes the DC voltage Vdc.
On the other hand, when the first IGBT
1
turns ‘OFF’ and the second IGBT
2
turns ‘ON’ by the DC driving signals
3
and
4
, the output signal Vout becomes the ground voltage GND, that is zero voltage. Thus, the first and second IGBTs
1
and
2
carries out the ‘ON’ and ‘OFF’ controls, thereby enabling to mainly carry out the function of an inverter.
In this case, the DC driving signals
3
and
4
should prevent the first and second IGBTs
1
and
2
from turning ‘ON’ simultaneously. If both of the IGBTs turned ‘ON’, the DC voltage Vdc and ground GND are shorted to allow a large flow of a current, thereby breaking down the IGBTs
1
and
2
. Thus, the DC driving signals
3
and
4
should have polarities opposite to each other absolutely. Moreover, the voltage applied between the gate and emitter of the first and second IGBTs
1
and
2
should be higher than a threshold voltage so as to drive the inverter.
FIG. 3
illustrates an IGBT inverter according to a prior art.
Referring to
FIG. 3
, an IGBT inverter according to a prior art includes a first IGBT
11
of which collector is connected to a DC voltage Vdc, a second IGBT
12
of which collector is connected to an emitter of the first IGBT
11
and of which emitter is connected to a ground GND, a first driving circuit
13
connected between gate and emitter of the first IGBT
11
so as to supply the gate of the first IGBT
11
with a driving voltage Vge through a first resistor R
1
, and a second driving circuit
14
connected between gate and emitter of the second IGBT
12
so as to supply the gate of the second IGBT
12
with a driving voltage Vge through a second resistor R
2
. In this case, an output signal Vout is outputted from a connection point between the first and second IGBTs
11
and
12
.
The above-constructed IGBT inverter according to a prior art, as explained in
FIG. 2
, controls ‘ON’ and ‘OFF’ of the first and second IGBTs
11
and
12
by applying the DC driving voltages between the gates and emitters of the first and second IGBTs through the first and second driving circuits
13
and
14
, respectively.
In this case, it is able to control speeds of ‘ON’ and ‘OFF’ between the collectors and emitters of the first and second IGBTs
11
and
12
respectively by adjusting current values applied to the gates of the first and second IGBTs
11
and
12
by setting up values of the first and second resistors R
1
and R
2
respectively. When the first or second IGBT
11
or
12
turns ‘ON’, voltages between the collectors and emitters are determined in accordance with the levels of the DC voltages applied thereto through the first and second driving circuits
13
and
14
.
In case that the first and second IGBTs
11
and
12
are ‘ON’ and ‘OFF’ respectively or ‘OFF’ and ‘ON’ respectively, operations of the IGBT inverter according to a prior art will be explained in detail by referring to FIG.
4
and
FIG. 5
in the following description.
FIG. 4
illustrates an operation of the first IGBT
11
in FIG.
3
.
Referring to
FIG. 4
, the first IGBT
11
turns ‘ON’ when the driving voltage is applied thereto at a time point of t
1
. In this case, when the DC voltage Vdc is applied between the collector and emitter of the second IGBT
12
, an output current I
1
flows toward an output voltage terminal and a current I
2
charging the equivalent capacitance Cge between the gate and emitter through the equivalent capacitance Ccg between the collector and gate of the second IGBT
12
is generated, simultaneously. Thus, a noise is generated from a driving signal of the second IGBT
12
during a short time for which electric charges charged in the equivalent capacitance Cge between the gate and emitter are discharged to the ground GND.
FIG. 5
illustrates an operation of the second IGBT
12
in FIG.
3
.
Referring to
FIG. 5
, the second IGBT
12
turns ‘ON’ when the driving voltage is applied thereto at a time point of t
2
. In this case, when the DC voltage Vdc is applied between the collector and enitter of the first IGBT
11
, an output current I
1
flows from the output voltage terminal to the ground GND. At the same time, a current I
2
charging the equivalent capacitance Cge between the gate and emitter through the equivalent capacitance Ccg between the collector and gate of the first IGBT
11
is generated. Thus, a noise is generated from a driving signal of the first IGBT
11
during a short time for which electric charges charged in the equivalent capacitance Cge between the gate and emitter are discharged to the ground GND.
As mentioned in the above explanation, the IGBT inverter according to the prior art, when the noise generated from the driving signal of the first or second IGBT gate exceeds the threshold voltage, makes both of the first and second IGBTs turn ‘ON’ so as to short the DC voltages and the ground each other. Therefore, a large current flows therebetween so as to break down the IGBTs.
Unfortunately, the IGBT inverter according to the prior art has difficulty in minimizing a gate driving distance not to make the noise exceed the threshold voltage as well as selecting the gate driving resistors and the driving circuits.
SUMMARY OF THE INVENTION
Accordingly
Birch & Stewart Kolasch & Birch, LLP
LG Industrial Systems Co. Ltd.
Tran Toan
LandOfFree
Circuit for driving gate of IGBT inverter does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Circuit for driving gate of IGBT inverter, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Circuit for driving gate of IGBT inverter will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3088916