JPH08308230A - Power converter - Google Patents

Abstract

PURPOSE: To prevent an AC circuit breaker from being impossible to be closed by providing protective sequence switching means for preventing the opening of the breaker before the lapse of a predetermined time is detected by timer means for detecting that the predetermined time is elapsed from the closing of the breaker and thereafter eliminating it. CONSTITUTION: A protective sequence switching circuit 8, a starting protective sequence circuit 9 and a timer 10 are newly added to a prior art apparatus. When a start command is applied, a common terminal (c) is connected to a switching terminal (a), and the fault signal of a fault discriminator 6 is applied to the circuit 9. When the set time of the timer 10 is elapsed, the terminal (c) is connected to a switching terminal (b) to apply the fault signal to a protective sequence circuit 7. The timer 10 outputs a time-up signal when the sufficient time to establish the voltage of a gate drive power source is elapsed, for example, after a close command is output, and applies a switching command to the circuit 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power converter which obtains, from a main circuit of a power converter, gate drive power for a self-arc-extinguishing element constituting the power converter.

[0002]

2. Description of the Related Art In recent years, self-excited power converters tend to have higher voltages and larger capacities. As a matter of course, a high withstand voltage element is used as the self-extinguishing element that constitutes this power converter. Conventionally, the gate drive voltage of this self-extinguishing element has generally been obtained from a low voltage control circuit via an isolation transformer. In this case, the insulation transformer must also have a high withstand voltage as the voltage of the power converter increases, and as a result, the power converter including the control system becomes large. As one method for suppressing this increase in size, research has been conducted on a main circuit gate power supply system in which electric power obtained from a high-voltage main circuit is charged into a capacitor and used as a gate drive power supply for a self-turn-off device.

FIG. 7 is a block diagram showing the configuration of a current type power converter of the conventional power converters adopting the gate power supply system. In the figure, a primary side of a transformer 3 for a converter is connected to a three-phase AC bus 1 via an AC breaker 2. The power converter 4 is connected to the secondary side of the converter transformer 3. As will be described later in detail, the power conversion unit 4 has six arms including a self-arc-extinguishing element and a snubber circuit connected in parallel therewith connected in Graetz, and the AC side terminal thereof has a transformer transformer. The secondary side of 3 is connected, and the DC reactor 5 is connected to one path on the DC side, for example, the positive voltage side.

Further, a fault discriminating circuit 6 and a protection sequence circuit 7 are provided to protect the power converter. Of these, the failure determination circuit 6 includes a comparator 6A that outputs a signal of logic "1" when the negative bias voltage V _C between each gate and cathode of the self-extinguishing element is all set value V ₀ or more, Gate power supply voltage V _G for supplying each arm
Is greater than the set value V _g0, it is composed of a comparator 6B which outputs a signal of logic "1" and a logical product circuit 6C which takes the logical product of the outputs of these two comparators. The protection sequence circuit 7 takes in the signal of the failure determination circuit 6 and failure information due to other factors, outputs an open command to open the AC circuit breaker 2 when a protection condition is satisfied, and other protection. Outputs sequence execution commands.

FIG. 8 is a block diagram showing the configuration of a voltage type power converter of the conventional power converters adopting the above-mentioned gate power supply system. In the figure, the same elements as those of FIG. 7 are designated by the same reference numerals, and the description thereof will be omitted. Here, the DC reactor 5 in FIG. 7 is removed, a DC capacitor 12 is connected between the DC terminals P and N instead of the DC reactor 5, an initial charging circuit 11 for charging the DC circuit, and this initial charging circuit. A DC breaker 2A for connecting 11 before operation is newly added, and a protection sequence circuit 7
However, it is not for the AC breaker 2 described above, but for the DC breaker
The configuration differs from that of FIG. 7 in that an opening command for 2A is output.

FIG. 9 is a circuit diagram showing a detailed structure of one arm of the current type power converter 4 and the gate drive circuit 47.
Here, the arm is a self-extinguishing element that constitutes a power converter.
41 and a rectifying element 42 as a snubber circuit for protecting this,
It is composed of a snubber resistor 43 and a snubber capacitor 44. Further, in order to use the charge / discharge current of the snubber circuit as the gate drive power, the current detector 46 is connected in series with the snubber capacitor 44.
Is provided. On the other hand, the gate drive circuit 47 is a rectifier.
47A, 47B, gate power supply capacitors 47C, 47D, and switching elements, etc., and the DC voltage of the DC circuit is supplied via the charging resistor 45 to the gate power supply capacitors 47C, 47D.
Is applied to both ends of the gate power supply capacitors 47C and 47D via the rectifiers 47A and 47B, respectively, and the output voltage of the current detector 46 is applied to both ends of the gate power supply capacitors 47C and 47D. The charging voltage of the gate power supply capacitor 47C is used for igniting the self-extinguishing element 41, and the charging voltage of the gate power supply capacitor 47D is used for extinguishing the self-extinguishing element 41. In addition, the gate power supply voltage detector 47E detects the voltage across the gate power supply capacitors 47C and 47D, that is, the gate power supply voltage V _G , and adds it to the failure determination circuit 6, while the voltage detector 47F outputs a negative voltage between the gate and the cathode. The bias voltage V _C is detected and applied to the failure determination circuit 6.

FIG. 10 is a circuit diagram showing the configuration of one arm of the voltage-type power converter 4 and an input circuit using the voltage across the arm as the gate drive power. The same elements as those of FIG. 9 are designated by the same reference numerals. And its description is omitted. In this case, the self-extinguishing element 41 is connected in anti-parallel with the rectifying element 42 for circulation.
In order to use the voltage generated across the self-arc-extinguishing element 41 for driving the gate, the series connection circuit of the starting resistor 48A and the gate power supply capacitor 48B, and the series connection circuit of the input capacitor 48D and the reactor 48E. Are connected in parallel to the self-extinguishing element 41, the anode of the rectifying element 48C is connected to the interconnection point of the input capacitor 48D and the reactor 48E, and the cathode of the rectifying element 48C is connected to the starting resistor 48A and the gate power supply. It is connected to the interconnection point of the supply capacitor 48B and also to the voltage input terminal of the gate drive circuit 47, for example, the terminal to which the rectifiers 47A and 47B in FIG. 9 are connected.

The supply of the gate drive voltage to the self-extinguishing element will be described below, including the operation of the main circuit. At startup, the gate power supply capacitors 47C and 47D in the gate drive circuit 47 shown in FIG. 9 are charged by the system voltage via the charging resistor 45. At the same time, the snubber capacitor 44 is also charged via the parallel circuit of the snubber resistor 43 and the rectifying element 42. When the self-extinguishing element 41 is fired by the charging voltage of the gate power supply capacitor 47C, the electric charge of the snubber capacitor 44 is discharged through the series circuit of the self-extinguishing element 41 and the snubber resistor 43. At this time, the discharge current is detected by the current detector 46, and the output voltage is applied to the gate power supply capacitors 47C and 47D via the rectifiers 47A and 47B in the gate drive circuit 47 to replenish the gate drive power. On the other hand, when the self-extinguishing element 41 is extinguished by the charging voltage of the gate power supply capacitor 47D, the main circuit current flows to the rectifying element 42 side and charges the snubber capacitor 44. At this time, the charging current of the snubber capacitor 44 is detected by the current detector 46, and the output voltage is passed through the rectifiers 47A and 47B in the gate drive circuit 47 to the gate power supply capacitor.
It is applied to 47C and 47D to replenish the gate drive power.

At the time of startup, the gate power supply capacitor 48B of the input circuit shown in FIG. 10 is charged by the DC voltage of the main circuit through the startup resistor 48A.
This charging voltage is used as a gate drive power supply. Also, at the same time as charging the gate power supply capacitor 48B,
The input capacitor 48D is also charged. Next, when the self-extinguishing element 41 is ignited, the electric charge of the input capacitor 48D is discharged through the series circuit of the self-extinguishing element 41 and the reactor 48E, and the discharge energy moves to the reactor 48E. At this time, the rectifying element 48C becomes conductive because a positive bias is applied to it, and the energy of the reactor 48E moves to the gate power supply capacitor 48B and is replenished as gate drive power. Further, when the self-extinguishing element 41 is extinguished, the main circuit current again flows through the series circuit of the input capacitor 48D and the rectifying element 48C to the gate power supply capacitor 48B to charge it.

[0010]

In the above-mentioned failure judging circuit 6, the gate power supply voltage is established and the self-extinguishing type element is provided.
It is detected that the negative bias voltage is applied to both ends of 41, and the protection sequence circuit 7 turns on the circuit breaker on the condition. In other words, when this condition is not satisfied, the AC breaker 2 is opened in the current type power converter and the DC breaker 2A is opened in the voltage type power converter.

On the other hand, in the main circuit gate power supply system, the charging / discharging current of the snubber capacitor 44 in the main circuit and the gate power supply capacitor 48B in the circuit connected between the anode and the cathode of the self-extinguishing type element 41 are used. Since the voltage is used as the power source, the voltage of the capacitor is zero at startup unless the system voltage or DC voltage is supplied. And as long as the capacitor voltage is zero, the gate power supply is unestablished,
The voltage across the self-extinguishing element is zero and does not become a negative bias, which means that the condition for closing the breaker is not satisfied.

Therefore, even if both the gate drive circuit and the self-arc-extinguishing element are sound, there is a case where the power converter cannot be permanently activated.
Further, there is a problem that it is impossible to judge the failure of the gate drive circuit and the self-extinguishing element.

The present invention has been made to solve the above-mentioned problems, and it is possible to accurately judge the failure of the gate drive circuit or the self-extinguishing element at the time of start-up, and the failure signal described above is used. It is an object of the present invention to obtain a power conversion device that can prevent a situation in which a circuit breaker cannot be closed and that can smoothly start up.

[0014]

A power converter according to a first aspect of the present invention charges a capacitor using at least one of an anode-cathode voltage of a self-extinguishing element and a charging / discharging current of a snubber circuit, and When the AC circuit breaker is opened at least when the charging voltage is not established or when the negative bias is not applied between the anode and cathode of the self-extinguishing element, the specified time has elapsed since the AC circuit breaker was turned on. It is provided with a timer means for detecting that this has occurred, and a protection sequence switching means for preventing the opening of the AC circuit breaker before the elapse of a predetermined time is detected by this timer means and thereafter canceling it.

According to another aspect of the power converter of the present invention, the capacitor is charged by using the anode-cathode voltage of the self-extinguishing element, and when the charging voltage is not established and the anode of the self-extinguishing element. When at least one of the negative biases is not applied between the cathodes, when opening the DC circuit breaker connecting the initial charging circuit, a timer means for detecting that a predetermined time has elapsed since the DC circuit breaker was turned on, A protection sequence switching means is provided for preventing the opening of the DC circuit breaker before the elapse of a predetermined time is detected by the timer means, and thereafter canceling the opening.

According to another aspect of the power conversion apparatus of the present invention, the capacitor is charged by using the charging / discharging current of the snubber circuit connected to the self-extinguishing element, and when the charging voltage is not established and the self-extinguishing operation is performed. A voltage monitoring means for detecting that the voltage of the capacitor forming the snubber circuit exceeds a predetermined value when the AC breaker is opened at least on the one side when no negative bias is applied between the anode and cathode of the element. Before the voltage monitoring means detects a predetermined value, the AC circuit breaker is prevented from being opened, and thereafter the protection sequence switching means is provided.

According to another aspect of the power conversion apparatus of the present invention, the voltage across the self-extinguishing element is used to charge the capacitor of the input circuit, and when the charging voltage is not established and the anode of the self-extinguishing element.・ A voltage that detects that the voltage of the capacitor that constitutes the input circuit exceeds a specified value when the DC circuit breaker that connects the initial charging circuit is opened at least on one side when no negative bias is applied between the cathodes. The monitoring means and the protection sequence switching means for preventing the opening of the DC circuit breaker before the predetermined value is detected by the voltage monitoring means and for canceling the protection circuit after that are provided.

According to a fifth aspect of the power converter, the capacitor is charged by using the charging / discharging current of the snubber circuit connected to the self-arc-extinguishing element, and when the charging voltage is not established and the self-arc-extinguishing. When a negative bias is not applied between the anode and cathode of the element, the AC circuit breaker is opened at least on the other hand, a timer means for detecting that a predetermined time has elapsed after the AC circuit breaker is turned on and a snubber circuit are provided. The AC circuit breaker is opened before any one of the voltage monitoring means for detecting that the voltage of the constituent capacitor exceeds a predetermined value, the timer means for a predetermined time, and the voltage monitoring means for detecting a predetermined value. Protection sequence switching means for blocking and then releasing.

The power converter according to claim 6 charges the capacitor of the input circuit by using the voltage across the self-extinguishing element, and when the charging voltage is not established and the anode of the self-extinguishing element. When at least one of the negative biases is not applied between the cathodes, when opening the DC circuit breaker connecting the initial charging circuit, a timer means for detecting that a predetermined time has elapsed since the DC circuit breaker was turned on,
Failure determination is performed before any one of the voltage monitoring means for detecting that the voltage of the capacitor constituting the input circuit exceeds a predetermined value, the lapse of a predetermined time by the timer means, and the predetermined value by the voltage monitoring means. And a protection sequence switching means for preventing the opening of the DC circuit breaker by the circuit and thereafter canceling it.

[0020]

In the power converter according to the first aspect of the present invention, the opening of the AC circuit breaker is blocked until a predetermined time elapses after the AC circuit breaker is turned on, and the AC circuit breaker is released thereafter. The conditions for charging the capacitor are adjusted.

In the power converter according to the second aspect of the present invention, the opening of the DC circuit breaker is blocked until a predetermined time elapses after the DC circuit breaker is turned on, and then the DC circuit breaker is released, so that the gate voltage is supplied. The charging conditions for the capacitor are adjusted.

In the power converter according to the third aspect of the invention, the AC circuit breaker is prevented from being opened until the voltage of the capacitor forming the snubber circuit exceeds a predetermined value, and then released. Conditions of the capacitor for use are adjusted.

In the power converter according to the fourth aspect of the present invention, the DC circuit breaker is prevented from being opened until the voltage of the capacitor forming the input circuit exceeds a predetermined value, and then released. Conditions of the capacitor for use are adjusted.

In the power converter according to the fifth aspect of the present invention, one of the conditions that a predetermined time has elapsed since the AC circuit breaker was turned on and that the voltage of the capacitor forming the snubber circuit exceeds a predetermined value is satisfied. The AC circuit breaker is prevented from being opened until it is satisfied, and then released, so that the charging condition of the capacitor for supplying the gate voltage can be more reliably adjusted.

In the power converter according to the sixth aspect of the present invention, either one of the condition that a predetermined time has passed since the DC circuit breaker was turned on and the voltage of the capacitor constituting the input circuit exceeds a predetermined value is satisfied. I blocked the opening of the DC breaker until it was satisfied, and released it after that.
The charging condition of the capacitor for supplying the gate voltage can be adjusted more reliably.

[0026]

The present invention will be described in detail below with reference to the embodiments shown in the drawings. FIG. 1 is a block diagram showing a configuration of a first embodiment of the present invention, which is applied to a current source power converter. In the figure, the same elements as those of FIG. 7 showing the conventional apparatus are designated by the same reference numerals, and the description thereof will be omitted. In this configuration, a protection sequence switching circuit 8, a startup protection sequence circuit 9 and a timer 10 are newly added to the configuration shown in FIG. Of these, the protection sequence switching circuit 8 has a common terminal c.
Is connected to the switching terminals a and b, the common terminal c is connected to the output terminal of the failure determination circuit 6, the switching terminal a is the input terminal of the startup protection sequence circuit 9, and the switching terminal b is They are connected to the input terminals of the protection sequence circuit 7, respectively. Then, when a start command is applied, the common terminal c is connected to the switching terminal a, the failure signal of the failure determination circuit 6 is added to the startup protection sequence circuit 9, and the common terminal c is set when the set time of the timer 10 has elapsed. Is connected to the switching terminal b to add a failure signal to the protection sequence circuit 7. The start-up protection sequence circuit 9 outputs a closing command to the AC circuit breaker 2 when the switching terminal a is connected to the common terminal c according to the start-up command regardless of the presence or absence of a failure signal. For example, a time-up signal is output and a switching command is added to the protection sequence switching circuit 8 when a time sufficient to establish the voltage of the gate drive power supply has elapsed since the closing command was output.

The operation of the present embodiment having the above-mentioned structure will be described below with particular emphasis on the parts that differ in structure from the conventional device. The AC breaker 2 is opened until the start command is given, and the protection sequence switching circuit 8 is in a neutral state in which it is not connected to either of the switching terminals a and b. When the start command is given, the protection sequence switching circuit 8 connects the common terminal c to the switching terminal a. This allows
The failure signal of the failure determination circuit 6 is given to the startup protection sequence circuit 9. The startup protection sequence circuit 9 outputs a closing command to the AC circuit breaker 2 regardless of whether the failure signal is "1" or "0". As a result, the power conversion unit 4
Is supplied with a three-phase AC voltage, and the gate power supply capacitor is charged.

When the AC breaker 2 is turned on, the timer 10 starts counting time. During this period, the protection sequence switching circuit 8 executes the protection operation on the failure information other than the failure signal, but does not execute the protection operation on the failure signal. Further, when the gate power supply capacitor is charged to establish the gate drive power supply voltage and a negative bias is applied between the anode and the cathode of the self-turn-off device, the failure determination circuit 6 has no failure. The signal of "1" indicating is output. Next, when the timer 10 has reached its set time,
A switching command is given to the protection sequence switching circuit 8. As a result, a signal indicating that the failure determination circuit 6 has no failure is applied to the protection sequence circuit 7, and thereafter, the protection sequence circuit 7 executes a predetermined protection operation including the failure signal in other failure information.

As a result, the AC circuit breaker 2 continues to be turned on from the start of operation until the charging of the gate power supply capacitor is completed, which prevents a situation in which the circuit breaker cannot be turned on due to a failure signal, and at the same time at the time of startup. The failure of the gate drive circuit or the self-extinguishing element can be accurately determined.

FIG. 2 is a block diagram showing the configuration of the second embodiment of the present invention, which is applied to a voltage type power converter. In the figure, the same elements as those of FIGS. 8 and 1 are designated by the same reference numerals, and the description thereof will be omitted. This embodiment is configured such that the DC protection circuit 2A is continuously turned on by the startup protection sequence circuit 9 from the start of operation until the charging of the capacitor for supplying the gate power is completed, and the control of the startup protection sequence circuit 9 is performed. The configuration is exactly the same as that of FIG. 1 except that the AC circuit breaker 2 is replaced with the DC circuit breaker 2A, and the same operation is performed, so description thereof will be omitted. Also in this embodiment, it is possible to prevent a situation in which the circuit breaker cannot be closed due to the failure signal, and at the same time, it is possible to accurately determine the failure of the gate drive circuit or the self-extinguishing element at the time of startup.

FIG. 3 is a block diagram showing the configuration of the third embodiment of the present invention, which is applied to a current source power converter. In the figure, the same elements as those of FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted. This differs from FIG. 1 in that the timer 10 shown in FIG. 1 is removed and a snubber capacitor voltage monitor 10A is provided instead. This snubber capacitor voltage monitor 10A starts detecting the voltage across the snubber capacitor 44 of the snubber circuit (see FIG. 9) which is connected in parallel with the self-extinguishing element after the AC breaker 2 is turned on.
A switching command is given to the protection sequence switching circuit 8 when the voltage reaches a level capable of driving the gate of the self-arc-extinguishing element. Also in this embodiment, it is possible to prevent a situation in which the circuit breaker cannot be closed due to the failure signal, and at the same time, it is possible to accurately determine the failure of the gate drive circuit or the self-extinguishing element at the time of startup.

FIG. 4 is a block diagram showing the configuration of the fourth embodiment of the present invention, which is applied to a voltage type power converter. In the figure, the same elements as those of FIG. 2 are designated by the same reference numerals, and the description thereof will be omitted. This differs from FIG. 2 in that the timer 10 shown in FIG. 2 is removed and an input capacitor voltage monitor 10B is provided in its place. This input capacitor voltage monitor 10B is the voltage across the gate power supply capacitor 48B of the input circuit (see FIG. 10) that is charged by the voltage across the self-extinguishing element after the DC breaker 2A is turned on. The detection is started, and a switching command is given to the protection sequence switching circuit 8 when the voltage reaches a level capable of driving the gate of the self-arc-extinguishing element. Also in this embodiment, it is possible to prevent a situation in which the circuit breaker cannot be closed due to the failure signal, and at the same time, it is possible to accurately determine the failure of the gate drive circuit or the self-extinguishing element at the time of startup.

FIG. 5 is a block diagram showing the configuration of the fifth embodiment of the present invention, which is applied to a current source power converter. In the figure, the same elements as those of FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted. This is different from the timer 10 shown in FIG. 1 in that the snubber capacitor voltage monitor shown in FIG.
It is 10A connected in parallel. The timer 10 and the snubber capacitor voltage monitor 10A start their respective operations after the AC circuit breaker 2 is turned on. When the timer 10 is up, the snubber capacitor voltage monitor 10A detects when the monitored voltage exceeds a predetermined value. A switching command is applied to the protection sequence switching circuit 8. Therefore, the protection sequence switching circuit 8
Performs the switching operation when either one of the lapse of time and the voltage rise is satisfied. Also in this embodiment, it is possible to prevent a situation in which the circuit breaker cannot be closed due to the failure signal, and at the same time, it is possible to accurately determine the failure of the gate drive circuit or the self-extinguishing element at the time of startup.

FIG. 6 is a block diagram showing the configuration of a sixth embodiment of the present invention, which is applied to a voltage type power converter. In the figure, the same elements as those of FIG. 2 are designated by the same reference numerals, and the description thereof will be omitted. This is different from the timer 10 shown in FIG. 2 in that the input capacitor voltage monitor 10 shown in FIG.
B is connected in parallel. The timer 10 and the input capacitor voltage monitor 10B start their respective operations after the AC circuit breaker 2 is turned on. When the timer 10 is up, the input capacitor voltage monitor 10B detects when the monitor voltage exceeds a predetermined value. A switching command is applied to the protection sequence switching circuit 8. Therefore, the protection sequence switching circuit 8 executes the switching operation when either one of the lapse of time and the voltage increase is satisfied. Also in this embodiment, it is possible to prevent a situation in which the circuit breaker cannot be closed due to the failure signal, and at the same time, it is possible to accurately determine the failure of the gate drive circuit or the self-extinguishing element at the time of startup.

[0035]

As is apparent from the above description, according to the present invention, it is possible to accurately judge the failure of the gate drive circuit or the self-extinguishing element at the time of start-up, and the circuit breaker is activated by the failure signal. It is possible to provide a power conversion device that can prevent a situation where it cannot be turned on and that can be started up smoothly.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a first embodiment of the present invention.

FIG. 2 is a block diagram showing the configuration of a second embodiment of the present invention.

FIG. 3 is a block diagram showing the configuration of a third embodiment of the present invention.

FIG. 4 is a block diagram showing the configuration of a fourth embodiment of the present invention.

FIG. 5 is a block diagram showing the configuration of a fifth embodiment of the present invention.

FIG. 6 is a block diagram showing the configuration of a sixth embodiment of the present invention.

FIG. 7 is a block diagram showing a configuration of a conventional power conversion device.

FIG. 8 is a block diagram showing another configuration of a conventional power conversion device.

FIG. 9 is a block diagram showing a detailed configuration of part of the conventional power conversion device shown in FIG. 7.

10 is a block diagram showing a detailed configuration of a part of the conventional power conversion device shown in FIG.

[Explanation of Codes] 1 AC Bus 2 AC Breaker 2A DC Breaker 3 Converter Transformer 4 Power Converter 5 DC Reactor 6 Failure Judgment Circuit 7 Protection Sequence Circuit 8 Protection Sequence Switching Circuit 9 Startup Protection Sequence Circuit 10 Timer 10A Snubber capacitor voltage monitor 10B Input capacitor voltage monitor 11 Initial charging circuit 12 DC capacitor 41 Self-extinguishing type element 44 Snubber capacitor 48B Gate power supply capacitor 48D Input capacitor

Claims (6)

[Claims] 1. A self-excited power converter in which a plurality of self-extinguishing elements are bridge-connected, a snubber circuit for protecting the self-extinguishing elements, and an AC terminal of the power converter connected to an AC system. An AC circuit breaker, and a capacitor using at least one of the anode-cathode voltage of the self-extinguishing element and the charging / discharging current of the snubber circuit, and the charging voltage is the driving power supply for the self-extinguishing element. And a failure signal is output at least when the voltage of the gate driving circuit is not established and when the negative bias is not applied between the anode and the cathode of the self-extinguishing element. A failure determination circuit that opens the AC circuit breaker, timer means that detects that a predetermined time has elapsed since the AC circuit breaker was closed, and this timer means detects whether a predetermined time has elapsed. Is the previously prevents opening of the AC circuit breaker according to the fault signal, then the power conversion apparatus that includes a protection sequence switching means for releasing. 2. A self-exciting power converter in which a plurality of self-extinguishing elements are bridge-connected, an initial charging circuit that outputs a DC voltage for charging a DC circuit of the power converter, and the power converter. A DC circuit breaker that connects the initial charging circuit to the power converter and an input circuit that charges a capacitor using the voltage across the self-extinguishing element before operating the device, A gate drive circuit as a drive power source for the self-arc-extinguishing element, and when the voltage of the gate drive circuit is not established, and an anode of the self-extinguishing element.
A failure determination circuit that outputs a failure signal and opens the DC circuit breaker at least when a negative bias is not applied between the cathodes, and a timer that detects that a predetermined time has elapsed since the DC circuit breaker was turned on. And a protection sequence switching means for preventing the DC circuit breaker from being opened due to the failure signal before the elapse of a predetermined time by the timer means and thereafter canceling the protection sequence switching means. 3. A self-exciting power converter in which a plurality of self-extinguishing elements are bridge-connected, a snubber circuit for protecting the self-extinguishing elements, and an AC terminal of the power converter connected to an AC system. An AC circuit breaker, a gate drive circuit that charges a capacitor using the charging / discharging current of the snubber circuit, and uses the charging voltage as a drive power source for the self-extinguishing element, and the voltage of the gate drive circuit is established. And a snubber circuit, and a failure determination circuit that outputs a failure signal to open the AC circuit breaker and at least one of when the negative bias is not applied between the anode and the cathode of the self-extinguishing element. Voltage monitoring means for detecting that the voltage of the constituent capacitors exceeds a predetermined value, and opening of the AC circuit breaker by the failure determination circuit before the predetermined value is detected by the voltage monitoring means. Prevent, then power converter and a protection sequence switching means for releasing the. 4. A self-exciting power converter in which a plurality of self-extinguishing elements are bridge-connected, an initial charging circuit that outputs a DC voltage for charging a DC circuit of the power converter, and the power converter. A DC circuit breaker that connects the initial charging circuit to the power converter and an input circuit that charges a capacitor using the voltage across the self-extinguishing element before operating the device, A gate drive circuit as a drive power source for the self-arc-extinguishing element, and when the voltage of the gate drive circuit is not established, and an anode of the self-extinguishing element.
A failure determination circuit that outputs a failure signal and opens the DC circuit breaker at least when a negative bias is not applied between the cathodes, and that the voltage of a capacitor that constitutes the input circuit exceeds a predetermined value. A power conversion device comprising voltage monitoring means for detecting, and protection sequence switching means for preventing the failure of the DC circuit breaker from being opened by the failure determination circuit before the predetermined value is detected by the voltage monitoring means, and thereafter canceling the protection sequence switching means. . 5. A self-exciting power converter in which a plurality of self-extinguishing elements are bridge-connected, a snubber circuit for protecting the self-extinguishing elements, and an AC terminal of the power converter connected to an AC system. An AC circuit breaker, a gate drive circuit that charges a capacitor using the charging / discharging current of the snubber circuit, and uses the charging voltage as a drive power source for the self-extinguishing element, and the voltage of the gate drive circuit is established. Not operating and at least one of when the negative bias is not applied between the anode and the cathode of the self-extinguishing element, a failure determination circuit that outputs a failure signal to open the AC circuit breaker, and the AC circuit breaker Timer means for detecting the passage of a predetermined time from the turning on, and voltage monitoring means for detecting that the voltage of the capacitor forming the snubber circuit exceeds a predetermined value,
Protection sequence switching means for preventing the AC circuit breaker from being opened by the failure determination circuit before any one of the predetermined time elapsed by the timer means and the predetermined voltage detected by the voltage monitoring means and thereafter released. A power conversion device comprising: 6. A self-exciting power converter in which a plurality of self-extinguishing elements are bridge-connected, an initial charging circuit that outputs a DC voltage for charging a DC circuit of the power converter, and the power converter. A DC circuit breaker that connects the initial charging circuit to the power converter and an input circuit that charges a capacitor using the voltage across the self-extinguishing element before operating the device, A gate drive circuit as a drive power source for the self-arc-extinguishing element, and when the voltage of the gate drive circuit is not established, and an anode of the self-extinguishing element.
A failure determination circuit that outputs a failure signal and opens the DC circuit breaker at least when a negative bias is not applied between the cathodes, and a timer that detects that a predetermined time has elapsed since the DC circuit breaker was turned on. Means, a voltage monitoring means for detecting that the voltage of the capacitor forming the input circuit exceeds a predetermined value, a predetermined time elapsed by the timer means, and a predetermined voltage detected by the voltage monitoring means. The power conversion device includes a protection sequence switching unit that prevents the DC circuit breaker from being opened by the failure determination circuit before and is released thereafter.