JPH09117145A - Gate power supply for converter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gate power supply for self-extinguishing element constituting a converter from the main circuit side. SOLUTION: A snubber circuit Cs is provided with a series circuit of a charging diode 17, a first capacitor 18 and a second capacitor 19. Energy is injected to the second capacitor 19 through on/off operation of self-extinguishing elements GTO1, GTO2 and the terminal voltage of second capacitor 19 is utilized as the gate power supply for self-extinguishing elements GTO1, GTO2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gate power source for a converter in which the gate power source for a self-turn-off device forming the converter is obtained from the main circuit side.

[0002]

2. Description of the Related Art In recent years, converters for converting alternating current into direct current or converting direct current into alternating current have become increasingly larger in capacity and higher in voltage.
Conventionally, the gate power source of the converter is generally supplied from the low voltage side to the self-extinguishing type element provided on the high voltage side through an insulating transformer. However, with the increase in the voltage of the converter, the withstand voltage of the insulating transformer is increased, and accordingly, the size of the entire converter is increased.

FIG. 7 is a main circuit configuration diagram of a converter to which the present invention is applied, in which U, V and W are AC terminals, P and N.
Is a direct current terminal, which converts the alternating current applied to the alternating current terminals U, V, W into direct current and outputs it to the direct current terminals P, N via the direct current reactor DCL, or the direct current applied to the direct current terminals P, N Is a converter having a function of converting the AC into an AC and outputting the AC to the AC terminals U, V, W. SU, SV, SW, and S
X, SY, and SZ represent arms that constitute the converter.

As shown in FIG. 8, each of the arms SU to SZ has a first self-arc-extinguishing element GTO1 having a first cathode.
Of the second self-extinguishing type GTO2 is connected to the cathode of the second diode D2 which is connected in parallel to the first series circuit in the forward polarity with the first series circuit to which the anode of the diode D1 is connected. The unit switching circuit includes a second series circuit connected to the first series circuit and a snubber capacitor Cs connected between the series connection point of the first series circuit and the series connection point of the second series circuit. By connecting the unit switching circuits of FIG. 8 in series, it is possible to increase the voltage of the converter.

FIG. 8 shows the minimum constituent elements of the converter. The basic operation of this circuit is self-extinguishing elements GTO1 and GT.
When O2 is off, anode terminal A → second diode D
The snubber capacitor Cs is charged along the path of 2 → snubber capacitor Cs → first diode D1 → cathode terminal K.

First and second self-extinguishing elements GTO1,
When the GTO2 is turned on, the charge of the snubber capacitor Cs is charged to the anode terminal A → the first self-extinguishing element GTO1 →
Snubber capacitor Cs → second self-extinguishing element GTO2 →
After the discharge is completed, the first and second diodes D1 and D2 are made conductive, and the load current flows through the respective series circuits. The operation of the converter of FIG. 7 in which the circuit of FIG. 8 is used as an arm is described in Japanese Patent Application No. 3-272908.
No. 5,849,088 (Japanese Patent Laid-Open No. 5-115178), the description of the operation is omitted here.

FIG. 9 is a diagram showing a gate circuit of the self-extinguishing element (GTO1 and GTO2 of FIG. 8) which constitutes one arm of FIG. 7, where u and v are AC power supply terminals for supplying gate power and 10A. Is a gate circuit of the first self-arc-extinguishing element GTO1, 11 is an insulating transformer, the alternating current obtained from the secondary winding 12A thereof is converted into direct current by the rectifier 13A, and the alternating current obtained from the secondary winding 12B is It is converted into direct current by the rectifier 13B.

The DC of the rectifier 13A is smoothed by the capacitor 14A, and the DC of the rectifier 13B is smoothed by the capacitor 14A.
Smoothed by B. If the switching element 15A is turned on by the on-gate signal, the capacitor 14A → the switching element 15A → the diode 16A → the gate G1 of the first self-extinguishing element GTO1 → the cathode K1 of the first self-extinguishing element GTO1 → the capacitor 14A An on-gate signal is applied to the first self-extinguishing element GTO1 along the path. The gate circuit 10B of the second self-arc-extinguishing element GTO2, which is configured similarly to the gate circuit 10A, also applies the on-gate signal to the second self-extinguishing element GTO2 at the same timing.

Switching device 1 eliminating the on-gate signal
When an off-gate signal is applied to 5B, switching element 1
5B is turned on, and the capacitor 14B → cathode K1 of the first self-arc-extinguishing element GTO1 → first self-arc-extinguishing element GT
An off-gate signal is applied to the first self-arc-extinguishing element GTO1 through the path of the gate G1 of O1, the diode 16B, the switching element 15B, and the capacitor 14B. At the same time, the gate circuit 10B also applies an off-gate signal to the second self-turn-off device GTO2.

[0010]

As described above, since the conventional gate circuit is provided with the insulating transformer 11 for insulating the low voltage side AC power source from the high voltage side, the converter has a large capacity. As the voltage of the main circuit becomes higher due to higher voltage, the insulation transformer 11 has higher withstand voltage and becomes larger.

Therefore, an object of the present invention is to provide a gate power supply for a converter in which the gate power supply is obtained from the main circuit side without providing an insulating transformer. The gate power supply of the present invention is not limited only to the gate power supply, and may be a protection signal associated with an element failure on the main circuit side, a failure of another main circuit side component, or an abnormality on the main circuit side. It is a generic term for control power supplies etc. for transmission to the low voltage side.

[0012]

To achieve the above object, the invention according to claim 1 is such that each arm of the converter has a cathode of a first self-arc-extinguishing element and an anode of a first diode. And a second series circuit in which a second self-arcing type anode is connected to the cathode of a second diode connected in parallel to the first series circuit in a forward polarity. A converter comprising a circuit and a unit switching circuit including a snubber capacitor connected between a series connection point of the first series circuit and a series connection point of the second series circuit, and a charging diode , A series circuit including a first capacitor and a second capacitor having a larger capacity than the first capacitor is connected in parallel to the snubber capacitor, and the first capacitor and the second self-extinguishing arc from the second capacitor. form Children of gate - is obtained by said obtaining bets power supply or the like.

According to a second aspect of the present invention, each arm of the converter has a first series circuit in which the anode of the first diode is connected to the cathode of the first self-arc-extinguishing element, and A second series circuit in which a second self-extinguishing anode is connected to the cathode of a second diode that is connected in parallel to the first series circuit with forward polarity, and a series connection of the first series circuit. A unit switching circuit including a snubber capacitor connected between a point and a series connection point of the second series circuit, wherein a first capacitor connected in parallel to the snubber capacitor and a charging capacitor A series circuit in which a diode, a second capacitor having a larger capacity than the first capacitor are arranged in this order, an anode is connected to a cathode of the first self-arc-extinguishing element, and a cathode is the charging diode. The discharging diode comprises is connected to the anode is obtained by said obtaining a gate power supply or the like of the second of said capacitor first and second self turn-off device.

Further, the invention described in claim 3 is the same as claim 2
It is characterized in that the first capacitor described in 1) also has the function of a snubber capacitor and the original snubber capacitor is omitted.

The invention according to claim 4 is characterized in that a resistor is provided in parallel with the first capacitor according to any one of claims 1 to 3. Furthermore, the invention described in claim 5 is, when the terminal voltage of the discharge resistor and the second capacitor reaches a predetermined value in parallel with the second capacitor according to any one of claims 1 to 4. It is characterized in that a series circuit including switching elements that are turned on is provided.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The invention described in claim 1 will be described below.
Description will be made with reference to the configuration diagram of FIG. Charging diode 1
7, the first capacitor 18, and the first capacitor 1
A series circuit composed of a second capacitor 19 having a larger capacity than 8 is connected in parallel to the snubber capacitor Cs, and the second capacitor 19 connects the first and second self-extinguishing elements G to each other.
The gate power source of TO1 and GTO2 is obtained.

The terminal voltage of the second capacitor 19 is subjected to DC / AC conversion or DC / DC conversion to stabilize the circuit 2.
0 is applied. The output of the stabilizing circuit 20 is a gate circuit 2 which provides a gate signal to the first self-turn-off device GTO1.
It is supplied to a gate circuit 21B which supplies a gate signal to 1A and the second self-turn-off device GTO2.

In the gate power source of the converter configured as described above, before operation, the anode terminal A → second diode D2 → snubber capacitor Cs → first diode D1.
→ The snubber capacitor Cs is charged in the path of the cathode terminal K. Similarly, the first capacitor 18 and the second capacitor 19 are charged via the charging diode 17.

Here, the capacitance of the first capacitor 18 is C
1 and the capacity of the second capacitor 19 is C2, C2
> C1 so that the first capacitor 18 and the second capacitor 18
Depending on the voltage division ratio of the condenser 19 of the
A voltage required for the input power source of the stabilizing circuit 20 is generated at 9. With the voltage of the second capacitor 19 as an input source, the gate circuit 2 is passed through the stabilizing circuit 20.
Since energy is supplied to 1A and 21B, the required gate output can be obtained before the converter starts operation.

From such a state, an on-gate signal is given to the first and second self-arc-extinguishing elements GTO1 and GTO2,
When the first and second self-extinguishing elements GTO1 and GTO2 are turned on, the electric charge of the snubber capacitor Cs is changed from the anode terminal A to the first self-extinguishing element GTO1 to the snubber capacitor Cs to the second self-extinguishing element. Discharge is started along the path from the element GTO2 to the cathode terminal K.

On the other hand, the first capacitor 18 and the second capacitor 19 do not discharge because the charging diode 17 is connected with a polarity that prevents discharge, and the voltage of the second capacitor 19 for supplying the gate power supply is not discharged. Will not disappear.

Since the first capacitor 18 and the second capacitor 19 are charged with the polarities shown, the charging diode 17 is in the reverse bias state. That is, the first capacitor 18 and the second capacitor 19 are equivalent to being separated from the main circuit of one arm of the converter. Therefore, when the discharge current of the snubber capacitor Cs reaches the peak value and the terminal voltage of the snubber capacitor Cs becomes “0”, the first and second diodes D1 and D2 become conductive, and the main circuit current becomes the first series current. The current is diverted to the circuit and the second direct circuit.

Next, the first and second self-arc-extinguishing elements GT
Snubber capacitor C when O1 and GTO2 turn off
s starts charging to the polarity shown again. On the other hand, if the voltage of the second capacitor 19 is lowered due to the energy supply to the gate circuits 21A and 21B, the voltage of the snubber capacitor Cs becomes the voltage of the first capacitor 18 and the voltage of the second capacitor 19. The charging diode 17 is turned on from the time point when it becomes equal to the sum of the above, and the voltage of the second capacitor 19 is recovered.

Hereinafter, the first and second self-turn-off devices GT
Energy is injected into the second capacitor 19 by repeating ON / OFF of O1 and GTO2, and the charging energy of the second capacitor 19 is further passed through the stabilizing circuit 20 to the gate circuits 21A and 21B. Sent.

Next, the invention according to claim 2 will be described with reference to FIG. 2 in which the same parts as those in FIG. The gate power supply of the converter of FIG. 2 is connected in parallel with the snubber capacitor Cs, and is connected with a series circuit in which a first capacitor 18, a charging diode 17 of the polarity shown, and a second capacitor 19 are arranged in this order. Furthermore, the first self-extinguishing element GTO
An anode is connected to the cathode of No. 1 and a discharging diode 22 whose cathode is connected to the anode of the charging diode 17 is provided.

Also in FIG. 2, similarly to FIG. 1, the capacitance of the first capacitor 18 is C1 and the second capacitor 19 is
If the capacity of C2 is C2, then there is a relationship of C2> C1, and the snubber capacitor Cs and the first and second capacitors 18 and 19 are charged with the polarities shown in FIG. ing.

If the first and second self-extinguishing elements GTO1 and GTO2 are turned on from such a state, the snubber capacitor Cs starts discharging as described above. Further, the first capacitor 18 also starts discharging via the discharging diode 22, but the second capacitor 19 does not discharge because the charging diode 17 is in the reverse bias state, and the second capacitor 19 for supplying the gate power supply. The voltage of 19 does not disappear.

Next, when the discharge current of the snubber capacitor Cs reaches the peak value, the terminal voltage of the snubber capacitor Cs is at "0", and by this time, the first capacitor 18 having a smaller capacity than the snubber capacitor Cs has already been reached. Has completed discharging, and the first and second diodes D1, D2
Conducts.

Next, the first and second self-arc-extinguishing elements GT
When O1 and GTO2 are turned off, the snubber capacitor Cs and the first capacitor 18 are charged again with the polarity shown. On the other hand, the voltage drop in the second capacitor 19 is also compensated for and the voltage returns to the predetermined voltage again.

Hereinafter, the first and second self-arc-extinguishing elements GT will be described.
Energy is always injected into the second capacitor 19 with the same polarity by the ON / OFF operation of O1 and GTO2, and the charging energy of the second capacitor 19 is sent to the gate circuit via the stabilizing circuit 20. To be

Next, the invention according to claim 3 will be described with reference to FIG. 3 in which the same parts as those in FIG.
The difference between FIG. 3 and FIG. 2 is that in FIG.
However, the snubber capacitor Cs is omitted in the gate power supply of the converter having the configuration of FIG. The snubber capacitor Cs includes the first and second self-extinguishing elements GT.
Charging starts when O1 and GTO2 turn off,
Discharge starts when it is turned on.

On the other hand, the first capacitor 18 shown in FIG. 2 also starts charging / discharging at the same timing. Therefore, if the capacitance of the first capacitor 18 is set to a value that exerts the function of the snubber capacitor Cs, the first capacitor 18 may have the function of the snubber capacitor Cs and the original snubber capacitor Cs may be omitted. it can.

Next, an embodiment of the invention described in claim 4 will be described with reference to FIG. 4 in which the same parts as those in FIG. 4 is different from FIG. 1 in that the first capacitor 1
8 is connected in parallel with the resistor 23. Resistor 2
By providing 3, the second capacitor 19 can be quickly charged to a predetermined voltage.

A similar effect can be obtained by providing a resistor 23 in parallel with the first capacitor 18 of the circuit of FIG. 2 and configuring it as shown in FIG. Further, a similar effect can be obtained by providing the resistor 23 in parallel with the first capacitor 18 of the circuit of FIG.

Next, an embodiment of the invention described in claim 5 will be described with reference to FIG. 6 in which the same parts as those in FIG. The circuit of FIG. 6 is different from the circuit of FIG. 1 in that the series circuit of the discharge resistor 24 and the switching element 25 is connected in parallel to the second capacitor 19 for supplying gate power. ing. The basic operation of FIG. 6 is the same as that of FIG.

Second capacitor 19 for supplying gate power
The voltage of the gate circuit 21A,
21B loss, first and second self-extinguishing element GTO
If the gate power loss (turn-on loss, turn-off loss) of 1 and GTO2 is equal, the voltage will be constant on average.

However, at the actual festival, in consideration of the operating state of the converter, the variation of the rated constant of each part, the change of the constant due to aging, etc., the second capacitor 19 has a larger energy than the actual energy consumption. Therefore, there is a possibility that the voltage of the second capacitor 19 gradually rises and may reach an overvoltage because it is selected.

Therefore, when the terminal voltage of the second capacitor 19 rises above a predetermined value, the switching element 25 is turned on and the discharge resistor 24 consumes the surplus energy of the second capacitor 19 to suppress the overvoltage.

The discharge resistor 24 and the switching element 2
The same effect can be obtained even if the series circuit composed of 5 is provided in parallel with the second capacitor 19 shown in FIGS. 2 to 5.

[0040]

As is apparent from the above description, according to the gate power source of the converter of the present invention, the gate power source of the converter is provided on the high voltage side by utilizing the on / off operation of the self-extinguishing element on the high voltage side. Since the energy is injected into the gate power supply capacitor that is used, it is possible to omit the insulating transformer that sends energy from the low voltage side to the high voltage side as in the conventional case, and it is possible to realize a compact converter. .

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a gate power supply of a converter showing an embodiment of the invention described in claim 1.

FIG. 2 is a configuration diagram of a gate power source of a converter showing an embodiment of the invention described in claim 2;

FIG. 3 is a configuration diagram of a gate power supply of a converter showing an embodiment of the invention described in claim 3;

FIG. 4 is a configuration diagram of a gate power source of a converter showing an embodiment of the invention described in claim 4;

FIG. 5 is a configuration diagram of a gate power supply of a converter showing another embodiment of the invention according to claim 4;

FIG. 6 is a configuration diagram of a gate power source of a converter showing an embodiment of the invention described in claim 5;

FIG. 7 is a main circuit configuration diagram of a converter to which the present invention can be applied.

FIG. 8 is a detailed circuit diagram of one arm that constitutes the converter of FIG.

FIG. 9 is a configuration diagram showing a gate circuit of a conventional converter.

[Explanation of symbols]

 A ... Anode terminal K ... Cathode terminal SU-SZ ... Arm DCL ... DC reactor U, V, W ... AC power supply terminal P, N ... DC terminal GTO1 ... Self-extinguishing element GTO2 ... Self-extinguishing element D1, D2 ... Diode Cs ... Snubber capacitor 11 ... Insulation transformer 12A, 12B ... Secondary winding 13A, 13B ... Rectifier 14A, 14B ... Smoothing capacitor 15A, 15B ... Switching element 16A, 16B ... Diode 17 ... Charging diode 18 ... 1st Capacitor 19 ... Second capacitor 20 ... Stabilizing circuit 21 ... Gate circuit 22 ... Discharge diode 23 ... Resistor 24 ... Discharge resistor 25 ... Switching element

Claims (5)

[Claims] 1. A first series circuit in which each arm of the converter has a cathode of a first self-extinguishing element to which an anode of a first diode is connected, and a forward polarity to the first series circuit. The second diode is connected to the cathode of the second diode connected in parallel.
Of a self-extinguishing type anode, and a snubber capacitor connected between the series connection point of the first series circuit and the series connection point of the second series circuit. In the converter including a unit switching circuit, a series circuit including a charging diode, a first capacitor, and a second capacitor having a larger capacity than the first capacitor is connected in parallel to the snubber capacitor, Two
A gate power supply for a converter, wherein the gate power supply for the first and second self-turn-off devices is obtained from the capacitor of FIG. 2. A first series circuit in which each arm of the converter has a cathode of a first self-extinguishing element to which an anode of a first diode is connected, and a forward polarity to the first series circuit. The second diode is connected to the cathode of the second diode connected in parallel.
Of a self-extinguishing type anode, and a snubber capacitor connected between the series connection point of the first series circuit and the series connection point of the second series circuit. A converter including a unit switching circuit, in which a first capacitor connected in parallel to the snubber capacitor, a charging diode, and a second capacitor having a larger capacity than the first capacitor are arranged in this order A circuit and a discharge diode whose anode is connected to the cathode of the first self-extinguishing element and whose cathode is connected to the anode of the charging diode. And a gate power source for the converter, which obtains the gate power source of the second self-extinguishing element. 3. The gate power supply for a converter according to claim 2, wherein the first capacitor also has a function of a snubber capacitor, and the snubber capacitor is omitted. 4. The gate power source for a converter according to claim 1, wherein a resistor is provided in parallel with the first capacitor. 5. A series circuit comprising a discharge resistor and a switching element which is turned on when the terminal voltage of the second capacitor reaches a predetermined value is provided in parallel with the second capacitor. A gate power supply for a converter according to any one of claims 1 to 4.