JP3339311B2 - Driver circuit for self-extinguishing semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving circuit for a voltage-controlled self-extinguishing semiconductor device such as an insulated gate bipolar transistor (hereinafter referred to as an IGBT) or a field-effect transistor. Driving of a voltage-controlled self-extinguishing semiconductor device having a function of suppressing a surge voltage generated during switching and a switching noise due to a voltage change rate between main terminals (dV / dt) while minimizing an increase. Circuit.

[0002] In the drawings, the same reference numerals indicate the same or corresponding parts.

[0003]

2. Description of the Related Art FIG. 5 shows a general circuit configuration of a voltage source inverter using an IGBT. In FIG. 1, a DC power supply 20 is connected in parallel with a smoothing capacitor 21 and IGBTs 24 to 27 and commutation diodes (FWDs) connected in anti-parallel with the respective IGBTs.
In this example, power is supplied to an inverter bridge circuit that outputs a single-phase alternating current, which includes 28 to 31.

[0004] With this inverter bridge, two
The AC output converted and generated by alternately turning on and off the IGBTs forming the two arms is supplied to a load composed of a resistor 22 and an inductance 23, and the load current I _L
Flow. Figure 6 is an operation explanatory diagram of the voltage source inverter shown in FIG. 5, FIG. 6 (a) is a stray inductance by circuit wiring, as shown and Ls, the load current I _L IGBT
FIG. 2B shows a circuit configuration when the IGBT 25 flows in the direction of the arrow through the IGBT 25, and FIG. 2B shows operation waveforms of the IGBT 25 and the diode 28 when the IGBT 25 is turned on and off.

[0005] Specifically, in FIG. 6 (b), when turning off the IGBT25, the load current I _L commutates to the diode 28, the collector current Ic flowing in the IGBT25 is reduced. A surge voltage ΔVp is generated by the current decrease rate [−di / dt] and the stray inductance Ls, and I
It is applied to the GBT 25 and its antiparallel diode 29 (not shown) (see FIG. 6B).

[0006] When the load current I _L to the diode 28 turns on the IGBT25 in flowing, the load current I _L
Commutates to the IGBT 25, and the current _ID flowing through the diode 28 decreases. After the current I _D decreases, the diode 28 reversely recovers. A surge voltage ΔV _D is generated by the current change rate [di / dt] and the stray inductance Ls at the time of the reverse recovery, and the diode 28 and its antiparallel IGBT 24 (FIG. Outside) (see FIG. 6 (b)).

The surge voltages ΔVp and ΔV _D are Ls ×
Because represented by di / dt, or in order to reduce the ΔVp and [Delta] V _D reduces the value of the stray inductance Ls, or with the [-di / dt) and (di / dt]
Need to be reduced. However, there is a structural limit in reducing the stray inductance Ls.
Generally, T is gently switched to reduce [di / dt] and [−di / dt] at the time of IGBT switching.

If the voltage change rate [dV / dt] of the IGBT and the diode when the current is cut off is abrupt, this will cause adverse effects such as malfunctions on peripheral circuits such as the gate drive circuit of the IGBT and the control circuit of the inverter as switching noise. Slow switching of the IGBT is effective in reducing this [dV / dt].

[0009]

FIG. 7 shows a conventional method of gently switching the IGBT in order to reduce the aforementioned [di / dt] and [-di / dt]. FIG.
In (a), an on / off signal 1 commanded externally
Drive voltage (gate-emitter voltage,
_VGE is an on power supply 15
Alternatively, the transistor 8 and the gate resistor 1
2 or a transistor 10 and a gate resistor 1
4 is input to the gate of the IGBT 25 via a series circuit.

Since the structure between the gate and the emitter of the IGBT 25 is regarded as a capacitor (referred to as a gate input capacitance), the charging and discharging time of the capacitor by the gate drive circuit can be adjusted by the gate resistors 12 and 14. That is, when the values of the turn-on gate resistor 12 and the turn-off gate resistor 14 are increased, the charge / discharge time of the gate portion of the IGBT 25 is delayed and the gate voltage of the IGBT 25 is increased.
Rise and fall of the emitter voltage V _GE becomes gentle, and as a result, IGBT25 performs gradual switching, suppression of the surge voltage ΔVp and [Delta] V _D by reduction of the [di / dt] and [-di / dt] , [D
V / dt], so that switching noise can be reduced.

FIG. 7 (b) shows the difference in the switching waveforms depending on the values of the gate resistors 12 and 14. The solid line shows the waveform when the values of the gate resistors 12 and 14 are reduced, and the dotted line shows the gate resistance. Examples of respective operation waveforms when the values of 12 and 14 are increased are shown. However,
In the above-described method, it takes time to charge the gate input capacitance, and the time from when the on / off signal 101 is input to the gate drive circuit to when the IGBT actually operates (that is, the IGBT current starts to rise or fall). Since the delay increases, switching of the IGBT in a short time becomes difficult, and a dead time (a period during which both the upper and lower arms are turned off) set to prevent a short circuit between the upper and lower arms of the bridge connection of the IGBT becomes longer. , There is a problem.

An object of the present invention is to provide a drive circuit for a voltage controlled type self-extinguishing type semiconductor device which can solve the above-mentioned problems.

[0013]

According to a first aspect of the present invention, there is provided a driving circuit for a self-extinguishing type semiconductor device, comprising the steps of: turning on a gate based on an ON command (ON signal of an ON / OFF signal 101); Means (switching circuit 6, steady-state transistor 8) for applying a direct-current power source (turn-on power source 15) through a first gate resistor for steady-state (gate resistor 12 for steady-state on), an off command (on / off) A first gate resistor for turning off the DC power source for turning off (the power source for turning off 16) to the gate based on the off signal of the signal 101)
4) In a drive circuit of a voltage-controlled self-extinguishing semiconductor device (eg, IGBT 25) provided with a means for applying via the switching circuit 6 (steady-off transistor 10), the self-extinguishing semiconductor device has a main current. Main emitter terminal (E
m) and an auxiliary emitter terminal (Es) through which a small current proportional to the main current flows. An inductance (current change rate detecting inductance 36) is connected between the main emitter terminal and the auxiliary emitter terminal. After inputting the command,
The start of the rise of the current of the inductance is detected, and the first gate resistance for turning on is detected for at least a predetermined period (T
32) means for switching to a second on-state gate resistance (turn-on gate resistance 11) having a value larger than this resistance (turn-on one-shot circuit 32, switching circuit 6, turn-on transistor 7, etc.), and an OFF command After the start of the input, the start of the fall of the current of the inductance is detected, and the first gate resistance for turning off is turned on for at least a predetermined period (T33). (A one-shot circuit 33 for turning off, a switching circuit 6, a transistor 9 for turning off, etc.).

According to a second aspect of the present invention, there is provided a driving circuit for a self-extinguishing type semiconductor device, wherein an ON direct-current power supply (ON power supply
5) means (switching circuit 6, steady-state transistor 8) for applying via a first gate resistor for steady-state (gate resistor 12 for steady-state ON), and an OFF command (OFF signal of ON / OFF signal 01) Means (switching circuit 6, steady-state transistor 10) for applying a DC power source for OFF (shut-off power source 16) to the gate via a first gate resistor for OFF (steady-state gate resistor 14) In a drive circuit for a voltage-controlled self-extinguishing semiconductor device (such as IGBT25), the self-extinguishing semiconductor device has a commutation diode (FWD29) in anti-parallel, and the self-extinguishing semiconductor device and the commutation diode Are connected in series to form a pair, the connection point of the series of the anti-parallel circuits is connected to a load, and the commutation diode passes a main current through a main anode terminal (Am). And an auxiliary anode terminal (As) through which a small current proportional to the main current flows. An impedance is connected between the main anode terminal and the auxiliary anode terminal. By detecting the start of the fall of the current of the impedance of the commutation diode (FWD28) of the anti-parallel circuit, the first gate resistor for turning on is turned on for at least a predetermined period (T32). Means for switching to a second gate resistance (turn-on gate resistance 11) (current change detection circuit 41, turn-on one-shot circuit 32, signal insulation means 42, switching circuit 6, turn-on transistor 7, etc.), and input of an OFF command Thereafter, similarly, the start of the rise of the impedance current is detected, and the first gate resistor for turning off is turned off for at least a predetermined period (T 3) means for switching to a second off-state gate resistance (turn-off gate resistance 13) having a value larger than this resistance (current change detection circuit 41, turn-off one-shot circuit 33, signal insulation means 43, switching circuit 6) , Turn-off transistor 9 etc.).

According to a third aspect of the present invention, there is provided a driving circuit for a self-extinguishing type semiconductor device according to the second aspect, wherein the impedance is a resistance (a current detecting resistor 35) or an inductance (a current detecting resistance 35). It consists of a current change rate detecting inductance 36). Claim 4
The drive circuit for a self-extinguishing type semiconductor element according to claim 2, wherein the pair of anti-parallel circuits constitute upper and lower arms for one phase of an AC output of an inverter bridge circuit. To do it.

According to a fifth aspect of the present invention, there is provided a drive circuit for a self-extinguishing semiconductor device according to any one of the first to fourth aspects, wherein the DC power supply for turning off is omitted. It is assumed that the terminals of the DC power supply are short-circuited. The operation of the present invention is as follows. That is, after the ON signal (OFF signal) of the ON / OFF signal 101 is given to the gate of the IGBT as a voltage-controlled self-extinguishing semiconductor device, it is considered that the main current of the IGBT has started rising (falling). Up to the point in time, a power supply for on (off) is applied to the gate of the IGBT via a gate resistor of a small value to speed up the charge (discharge) of the gate input capacitance, and then an on signal (off signal) is given to the IGBT. This prevents an increase in time delay until the current of the IGBT actually starts rising (falling).

The main current of the IGBT rises (falls)
Is considered to have started, the gate resistance of the IGBT is switched to a large value for at least a predetermined period of time, and the rise (fall) of the gate-emitter voltage V _GE of the IGBT is moderated, whereby the IGBT is The rise (fall) of the current is gradual, in other words, di / dt
(−di / dt) is reduced.

The main current of the IGBT rises (falls)
IGBT to detect when it is deemed to have started
A main emitter terminal for flowing the main current and an auxiliary emitter terminal for flowing a small current proportional to the main current are provided, and an inductance is connected between the main emitter terminal and the auxiliary emitter terminal. A main anode terminal for flowing the main current through a commutation diode connected in anti-parallel to the IGBT and a small current proportional to the main current are detected. And an impedance consisting of resistance or inductance is connected between the main anode terminal and the auxiliary anode terminal, and an opposite arm (paired arm) in series with its own arm during bridge connection of the IGBT is provided. From the voltage of the impedance of the commutation diode connected in anti-parallel to the IGBT, the time when the current starts to fall (rises) And out to (claim 2).

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION

(Embodiment 1) FIG. 1 is a configuration diagram of a drive circuit for a voltage-controlled self-extinguishing type semiconductor device according to an embodiment (referred to as Embodiment 1) of the invention according to claim 1, which is shown in FIG. Only the drive circuit corresponding to the IGBT 25 of the voltage source inverter shown in FIG. 7 is shown, and therefore, those having the same functions as those in the circuit shown in FIG.

However, here, the values of the gate resistors 12 and 14 are both selected to be small, and are referred to as a steady-state gate resistance and a steady-off gate resistance, respectively. The transistors 8 and 10 are also referred to as a steady on transistor and a steady off transistor, respectively. That is, in FIG. 1, a switching circuit composed of a series circuit of the steady-on gate resistor 12 and the steady-on transistor 8 and the steady-off gate resistor 1
In addition to a switching circuit comprising a series circuit of a transistor 4 and a steady-state transistor 10, a series circuit of a turn-on gate resistor 11 and a turn-on transistor 7 having a larger resistance than the steady-state gate resistor 12 is provided. Switching circuit and gate resistor 14 for steady OFF
A switching circuit including a series circuit of a turn-off gate resistor 13 having a larger resistance value and a turn-off transistor 9 is provided in parallel.

In FIG. 1, a small current (referred to as an auxiliary emitter current) proportional to the main collector current is taken out of the IGBT 25 separately from the main emitter terminal Em through which the main current (main emitter current ≒ main collector current Ic) flows. An auxiliary emitter terminal Es is provided. Here, the auxiliary emitter terminal Es is connected to the main emitter terminal Em via an inductance 36 for detecting the current change rate of the main collector current, and the current change rate detection inductance 36 has a change in the main collector current Ic. A voltage signal (di / dt signal) 106 proportional to the rate is generated. This d
The magnitude Vs of the i / dt signal 106 is Vs = (inductance value of inductance 36) × (main collector current I
(the rate of change of the auxiliary emitter current in proportion to c).

Di / dt at turn-on and turn-off
The signal 106 is a one-shot circuit 3 for turn-on.
2 and a switching circuit 6 via a one-shot circuit 33 for turning off. The switching circuit 6 is composed of a logic circuit, and receives an on / off signal 101, an output signal 102 of a turn-on one-shot circuit 32, and an output signal 103 of a turn-off one-shot circuit 33, and drives the transistors 7 to 10. Switch.

FIG. 2 is a waveform diagram for explaining the operation of FIG.
Next, the operation of FIG. 1 will be described with reference to FIG. First IG
The turn-on operation of the BT 25 will be described. When the ON signal (value “1”) of the ON / OFF signal 101 is input to the switching circuit 6 at the time t1 in FIG. 2, the switching circuit 6 first turns on the steady-on transistor 8 and turns on the gate of the IGBT 25. A power supply 15 is applied through the steady-state gate resistor 12. As described above, the steady-state gate resistance 12 is set smaller than the turn-on gate resistance 11, and the gate input capacitance of the IGBT 25 is rapidly charged (in the positive direction in this example), and the gate voltage V _GE is increased. As a result, the main collector current Ic starts rising at time t2, and at the same time, the auxiliary emitter current of the IGBT 25 also starts rising.

As a result, the current change rate detecting inductance 36 has a di / d
The dt signal 106 is generated. This di / dt signal 106
, A turn-on one-shot circuit 32 is triggered, and this one-shot circuit 32 outputs a "1" one-shot signal 102 for a predetermined time T32. The switching circuit 6 turns off the steady-on transistor 8 and turns on the turn-on transistor 7 while the one-shot signal 102 is present.

Therefore, during this period T32, the IGBT 25
Is charged by the large gate resistor 11, the gate voltage _VGE gradually rises, and the main collector current Ic also slowly rises. And the main collector current Ic
Is established to almost the final level at time t3 when the period T32 has elapsed. At time t3, the one-shot signal 102 disappears and becomes “0”, and the switching circuit 6 supplies the ON signal 1 of “1”.
Only 01 remains as input. As a result, the switching circuit 6 turns off the turn-on transistor 7 and turns on the steady-on transistor 8. Therefore the gate voltage V _GE stops to rise to reach the voltage on power supply 15 to quickly rise again, whereas, the forward voltage drop of the IGBT25 (collector-emitter voltage) V _CE is saturated descends rapidly . Thus, IGBT 25 is completely turned on immediately.

Next, the turn-off operation of the IGBT 25 will be described. When the on / off signal 101 input to the switching circuit 6 is switched to an off signal (value “0”) at time t4, the switching circuit 6 turns off the steady-on transistor 8 and simultaneously turns on the steady-off transistor 10. , An off power supply 16 is applied to the gate of the IGBT 25 via the steady off gate resistor 14. The steady-state gate resistor 14 is set to be smaller than the turn-off gate resistor 13 as described above, and the gate input capacitance of the IGBT 25 is rapidly discharged (toward the negative direction) so that the gate voltage V _GE is quickly increased. This causes the main collector current Ic to start falling at time t5, and at the same time the auxiliary emitter current of the IGBT 25 starts to fall.

As a result, the current change rate detecting inductance 36 has a di /
A dt signal 106 (however, a polarity opposite to the rising edge of the main collector current Ic) is generated. At the falling edge of the front end of di / dt signal 106, turn-off one-shot circuit 3
3 is triggered, and the one-shot circuit 33 outputs the one-shot signal 103 of “1” for a predetermined time T33. The switching circuit 6 turns off the steady-off transistor 10 and turns on the turn-off transistor 9 while the one-shot signal 103 is present.

Therefore, during this period T33, the IGBT 25
Is discharged by the large gate resistor 13, the gate voltage V _GE gradually decreases, the main collector current Ic also gradually decreases, and attenuates to almost the final level at time t6 when the period T33 has elapsed. . At time t6, the one-shot signal 103 disappears and becomes “0”, and only the “0” off signal 101 remains in the switching circuit 6 as an input.
Thus, the switching circuit 6 turns off the turn-off transistor 9 and turns on the steady-off transistor 10. Then, the gate voltage _VGE rapidly drops again to turn off the power supply 1
When the voltage reaches the voltage of 6, the descent is stopped. In this way I
GBT 25 is completely turned off immediately.

(Embodiment 2) FIG. 3 is a structural view of a main part of an embodiment (hereinafter referred to as Embodiment 2) of the invention according to claim 2. This figure shows the gate drive circuits of the IGBTs 24 and 25 constituting the pair of upper and lower arms corresponding to one phase of the AC output in the bridge circuit of the voltage source inverter shown in FIG. 5, and the configuration of the gate drive circuit of the IGBT 25. Corresponds to FIG. Here, for the sake of convenience, the operation of the gate drive circuit will be described for the IGBT 25.
The same applies to No. 4.

In FIG. 3, IGBTs 24, 25
Commutation diodes (FWD) 2 connected in anti-parallel to
In addition to the main anode terminal Am through which the main current flows, an auxiliary anode terminal As for taking out a small current (referred to as an auxiliary anode current) proportional to the main current is provided at 8, 29. The auxiliary anode terminal As is connected to the main anode terminal Am via the current detection resistor 35.

The anode current signal 105 as the voltage of the current detection resistor 35 is converted into a current change detection signal 107 as a trigger pulse via the current change detection circuit 41, and the turn-on one-shot circuit 32 and the turn-off one-shot are used. The one-shot signals 102, 103 as outputs of the one-shot circuits 32, 33 are supplied to a circuit 33, respectively.
A switching circuit 6 for the opposite arm in the upper and lower arms of the inverter bridge circuit via photocouplers 42 and 43 which operate faster than the switching time of the BT.
Given to. That is, F is supplied to the switching circuit 6 of the IGBT 25.
A signal based on the voltage of the current detection resistor 35 of the WD 28 is
A signal based on the voltage of the current detection resistor 35 of the FWD 29 is supplied to the switching circuit 6 of the IGBT 24.

FIG. 4 is a waveform diagram for explaining the operation of FIG.
Next, the operation of FIG. 3 will be described with reference to FIG. First IG
The turn-on operation of the BT 25 will be described. At time t1 in FIG. 4, the ON signal of the ON / OFF signal 101 (value “1”)
Is input to the switching circuit 6 of the IGBT 25, the switching circuit 6 first turns on the steady ON transistor 8,
An on power supply 15 is applied to the gate of the BT 25 via the steady on gate resistor 12. Thus (in this example the positive direction) rapidly gate input capacitance of similarly IGBT25 Example 1 rapidly increases and the gate voltage V _GE is charged, the main collector current Ic at time t2 begins to rise.

[0033] At the same time at this point t2, the current I _D flowing in the FWD28 opposite arm as the load current I _L starts decreasing (falling), the auxiliary anode current of FWD28, hence as the voltage of the current detection resistor 35 Of the anode current signal 105 also starts falling. The anode current signal 105 is input to the current change detection circuit 41.

The current change detecting circuit 41 includes a differentiating circuit in this example.
By detecting a falling speed equal to or greater than a predetermined value of
A trigger pulse in the positive direction as shown in FIG. 4 as the current change detection signal 107 is generated. Such a trigger pulse when the load current I _L is known in advance at a value close to the load current I _L, and placed defining a reference value of a predetermined falling below load current I _L, The comparator circuit can be used to generate the current ID of the FWD 28 when the current _ID falls below the reference value.

The turn-on one-shot circuit 32 is triggered by the current change detection signal 107, and the one-shot circuit 32 outputs the "1" one-shot signal 102 for a predetermined time T32. The one-shot signal 102 is converted into a signal of the same waveform which is insulated by the signal insulating means 42 and input to the switching circuit 6. The switching circuit 6 turns off the steady on transistor 8 during the period in which the isolated one-shot signal 102 is present,
The turn-on transistor 7 is turned on.

Therefore, in this period T32, the main collector current Ic rises slowly as in the case of the first embodiment, and reaches almost the final level at time t3 when the period T32 has elapsed. At time t3, the one-shot signal 102 disappears and becomes "0", and the output of the signal insulating means 42 also disappears. As a result, only the ON signal 101 of "1" remains as an input to the switching circuit 6, and the switching circuit 6 turns off the turn-on transistor 7 and turns on the steady-on transistor 8. Thus, IGBT 25 is completely turned on immediately.

Next, the turn-off operation of the IGBT 25 will be described. At time t4 in FIG. 4, the on / off signal 101 input to the switching circuit 6 of the IGBT 25 is an off signal (value “0”).
The switching circuit 6 switches to the steady-state transistor 8
Is turned off, and at the same time, the steady-off transistor 10 is turned on, and the off power supply 16 is applied to the gate of the IGBT 25 via the steady-off gate resistor 14. Thus the gate input capacitance of similarly IGBT25 Example 1 rapidly (toward the negative direction) discharged by the gate voltage V _GE is lowered rapidly, the main collector current Ic at time t5 starts falling.

At the same time, at time t5, the FW of the opposite arm is
The current _{ID of} D28 also starts to rise, and the auxiliary anode current of FWD28, that is, the anode current signal 105 as the voltage of the current detection resistor 35 also starts to rise. The current change detection circuit 41 outputs the anode current signal 1 at this time.
By detecting a rising speed equal to or higher than the predetermined value of 05, a negative trigger pulse shown in the current change detection signal 107 of FIG. 4 is generated. Even when such a trigger pulse to the current change detection circuit 41 consists of the comparator circuit corresponds to the pre-load current I _L, placed define a predetermined rising edge of the reference value close to 0, FWD28 current I
It can also be generated when _D exceeds this reference value.

The turn-off one-shot circuit 33 is triggered by the current change detection signal 107, and the one-shot circuit 33 outputs the "1" one-shot signal 103 for a predetermined time T33. The one-shot signal 103 is converted into a signal having the same waveform, which is insulated by the signal insulating means 43, and is input to the switching circuit 6 of the IGBT 25.

The switching circuit 6 turns off the steady-off transistor 10 and turns on the turn-off transistor 9 while the isolated one-shot signal 103 is present. Accordingly, in the period T33, the main collector current Ic of the IGBT 25 gradually falls as in the case of the first embodiment, and attenuates to almost the final level at the time t6 when the period T33 has elapsed.

At time t6, the one-shot signal 103 disappears and becomes "0", and the output of the signal insulating means 43 also disappears.
As a result, only the OFF signal 101 of "0" remains as an input to the switching circuit 6 of the IGBT 25, and the switching circuit 6 turns off the turn-off transistor 9 and turns on the steady-off transistor 10. Thus, the IGBT 25 is completely turned off immediately.

In the above embodiment, at the time of switching of the IGBT 25, the gate resistance is switched from a low-resistance steady-state (off) gate resistance to a high-resistance turn-on (turn-off) gate resistance. Normally, the gate resistance is returned to the steady on (off) gate resistance having a small resistance value. However, returning the gate resistance to the low resistance in this manner reduces the forward voltage drop V _CE of the IGBT at the time of turn-on. It is effective for reducing the switching loss quickly and reducing the switching loss.
Although effective to prevent erroneous turn-on of the IGBT due to V / dt, none of them is irrelevant to the delay of the switching time and is not essential to the present invention.

In FIG. 3, the current detecting resistor 35 connected between the main anode terminal Am and the auxiliary anode terminal As of the FWDs 28 and 29 is connected to the current change rate detecting inductance 3.
6, the current change detection circuit 41 between the auxiliary anode terminal As, the turn-on one-shot circuit 32 and the turn-off one-shot circuit 33 is deleted (however, in this case, the current change rate Since the relationship between the detection of the rise and fall of the current of the detection inductance 36 is opposite to that in FIG. 1, the output (di / dt signal 106) is output.
Must be inverted from that of FIG. ), IGBT2
5 can be performed in the same manner as in the second embodiment.

In the above embodiment, the description has been made by using the IGBT. However, the present invention is also effective as another voltage control type self-extinguishing semiconductor device, for example, a MOS FET. In the above embodiment, two power supplies, an on power supply and an off power supply, are used. However, the gate drive circuit can function effectively even when the off power supply is omitted and the terminals of the off power supply are short-circuited. .

[0045]

According to the present invention, the main emitter terminal Em for flowing the main collector current Ic to the IGBT and the auxiliary emitter terminal Es for extracting a small auxiliary emitter current proportional to the main collector current are provided. An inductance is connected between the emitter terminal Es and the IG.
Commutation diode (FWD) connected in anti-parallel to BT
A main anode terminal Am through which the main current flows, and an auxiliary anode terminal As for extracting a small auxiliary anode current proportional to the main current. A resistance or an inductance is provided between the main anode terminal Am and the auxiliary anode terminal As. By connecting an impedance and detecting a time point at which the rise (fall) of the main collector current Ic of the IGBT is considered to be started from the voltage of the inductance or the impedance, the gate of the IGBT is turned on (turned off) when the IGBT is turned on (turned off). Since the gate resistance inserted in series with the power supply to which the bias is applied is switched from a low resistance inserted in advance based on an ON command (OFF command) to a resistor having a larger value, an ON command (OFF command) is input. And then
Indeed current of the IGBT rises (falling) without increasing the time delay until the start, to mitigate the rate of rise of the gate voltage V _GE of the IGBT (descending), the IGBT di / dt (-di / dt ) Reduction in surge voltage Δ
Switching noise can be reduced by suppressing V _D (ΔVp) and reducing dV / dt.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a main part as one embodiment of the invention according to claim 1;

FIG. 2 is a waveform chart for explaining the operation of FIG. 1;

FIG. 3 is a block diagram showing a configuration of a main part as one embodiment of the invention according to claim 2;

FIG. 4 is a waveform chart for explaining the operation of FIG. 3;

FIG. 5 is a configuration diagram of a general power converter using an IGBT.

FIG. 6 is an explanatory diagram of the operation in FIG. 5;

FIG. 7 is an operation explanatory diagram of FIG. 5;

[Explanation of symbols]

Reference Signs List 6 Switching circuit 7 Turn-on transistor 8 Steady-on transistor 9 Turn-off transistor 10 Steady-off transistor 11 Turn-on gate resistor 12 Steady-on gate resistor 13 Turn-off gate resistor 15 On power source 16 Off power source 20 DC power source 21 Capacitor 24 to 27 IGBT Em main emitter terminal Es auxiliary emitter terminal 28 to 31 commutation diode (FWD) Am main anode terminal As auxiliary anode terminal 32 one-shot circuit for turn-on 33 one-shot circuit for turn-off 35 current-detecting resistor 36 current change rate Detection inductance 41 Current change detection circuit 42, 43 Signal insulation means 101 ON / OFF signal 102 One-shot signal (output of turn-on one-shot circuit 32) 103 One-shot No. (output turnoff one-shot circuit 33) 105 anode current signal 106 di / dt signal 107 current change detection signal

Claims (5)

(57) [Claims] A means for applying a DC power source for ON to a gate through a first gate resistor for ON based on an ON command;
A drive circuit for a voltage-controlled self-extinguishing semiconductor device, comprising: means for applying an off direct-current power to a gate via a first off-gate resistor based on an off command. Has a main emitter terminal through which the main current flows and an auxiliary emitter terminal through which a small current proportional to the main current flows, and an inductance is connected between the main emitter terminal and the auxiliary emitter terminal. Means for switching the first gate resistance for ON to a second gate resistance for ON having a value greater than this resistance for at least a predetermined period by detecting the start of the rise of the current of the inductance; and The first gate resistance for turning off is detected for at least a predetermined period by detecting the start of the fall of the current of the inductance, and the second gate resistance for turning off having a value larger than this resistance is provided for at least a predetermined period. Driving circuit of the self-extinguishing type semiconductor element characterized in that a means for switching the sheet resistance. 2. A means for applying a DC power source for ON to a gate through a first gate resistor for ON based on an ON command.
A drive circuit for a voltage-controlled self-extinguishing semiconductor device, comprising: means for applying an off direct-current power to a gate via a first off-gate resistor based on an off command. Has a commutation diode in anti-parallel, and two anti-parallel circuits of the self-extinguishing type semiconductor element and the commutation diode are connected in series to form a pair, and the series connection point of the anti-parallel circuits is The commutation diode is connected to a load, has a main anode terminal through which a main current flows, and an auxiliary anode terminal through which a small current proportional to the main current flows, and an impedance is connected between the main anode terminal and the auxiliary anode terminal. After the input of the ON command, the start of the fall of the current of the impedance of the commutating diode of the anti-parallel circuit of the mating partner is detected to reduce the first gate resistance for ON. Means for switching to a second gate resistance for turning on having a value larger than this resistance for a predetermined period; and after inputting an off command, detecting the start of rise of the current of the impedance and detecting the first gate for turning off. Means for switching the resistance to a second off-state gate resistance having a value greater than the resistance for at least a predetermined period of time. 3. The circuit for driving a self-extinguishing semiconductor device according to claim 2, wherein said impedance comprises a resistance or an inductance. 4. The self-turn-off semiconductor device driving circuit according to claim 2, wherein said pair of anti-parallel circuits constitute upper and lower arms for one phase of an AC output of an inverter bridge circuit. Drive circuit for arc-extinguishing semiconductor devices. 5. The driving circuit for a self-extinguishing semiconductor device according to claim 1, wherein the DC power supply for turning off is omitted, and terminals of the DC power supply are short-circuited. Circuit for driving self-extinguishing semiconductor devices.