JPH11355905A - Power converter shutoff system - Google Patents

Abstract

(57) [Summary] [PROBLEMS] In a power conversion device cutoff system that receives supply of power from a DC power supply and converts a DC voltage into an AC voltage, cost reduction / maintenance saving, and smoothing of a filter circuit accompanying the cutoff. There is a problem of overcharging the capacitor. A first semiconductor cut-off having a DC breaker for mechanically shutting off a power supply between a DC power supply and a DC reactor, wherein a semiconductor element cuts off current between the DC reactor and an anode terminal of a smoothing capacitor. Machine. Further, the first semiconductor circuit breaker is operated to suppress the rush current when charging the smoothing capacitor. Furthermore, when the operation of the power converter is stopped or the first semiconductor circuit breaker is turned off, a series body of a second semiconductor circuit breaker including a semiconductor element and a resistor is used to consume the energy of the DC reactor.
It is connected in parallel between the connection point between the DC reactor and the first semiconductor circuit breaker and the cathode terminal of the smoothing capacitor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shut-off system for a power converter that receives power supplied from a DC power supply and converts a DC voltage into an AC voltage.

[0002]

2. Description of the Related Art As a prior art, for example, Patent No. 2608
The configuration shown in FIG. In the configuration of FIG. 1, a pantograph for collecting power from a DC power supply, a circuit breaker for cutting off an electric circuit and a high-speed circuit breaker are connected, and then an inverter as a power converter for converting DC power to AC power and its inverter. An induction motor as a load is illustrated.

Further, a gate turn-off thyristor (GTO) is used as a semiconductor constituting an inverter.
Each GTO is connected to a gate drive circuit to individually control the ON / OFF state of the GTO.

[0004] It is noted that a circuit breaker and a high-speed circuit breaker are connected in series as this DC side cutoff system. In order to interrupt the current, these circuit breakers have an arcing chip for interrupting the current and require regular maintenance. In general, the high-speed circuit breaker and the high-speed circuit breaker have a higher current interrupting capability, and play a role of disconnecting the inverter from the DC power supply by opening the electrode when a DC short-circuit failure occurs in the inverter.

On the other hand, in the case of an electric car, the role of the circuit breaker is a powering mode for accelerating the train and a brake mode for decelerating the train, and has a function of cutting off the circuit when these modes end. . However, there is a GTO as a function of interrupting a circuit. By turning off all the gates of the GTO, power supply to the induction motor, which is a load, can be stopped. That is, it can be seen that the GTO, which is the semiconductor element of the circuit breaker and the inverter, has a common function.

Further, as a shut-off system for a DC electric vehicle,
It is described in JP-A-4-322101. Generally, a filter circuit including a DC reactor and a smoothing capacitor is provided on the DC side of the inverter, and DC power to the circuit is supplied from a pantograph through a plurality of contactors and a high-speed circuit breaker.

[0007]

In the prior art, a high-speed circuit breaker is used as a breaking system. However, this has a problem that it hinders cost reduction and labor saving of maintenance. Although not described in the section of the prior art, a special circuit for suppressing an inrush current when the smoothing capacitor is initially charged before the inverter is started is required. Becomes
Furthermore, since the DC reactor of the filter circuit is located between the high-speed circuit breaker and the smoothing capacitor, the transient phenomenon occurs when the high-speed circuit breaker is turned off (opened) due to an overcurrent or when the inverter stops operating. There is a problem that the energy of the DC reactor overcharges the smoothing capacitor.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention relates to a power supply cutoff system for converting a DC voltage into an AC voltage by receiving power from a DC power supply. A DC circuit breaker for mechanically interrupting a current supplied from the DC power supply between the DC power supply point and the DC reactor, having a filter circuit comprising at least a DC reactor and a smoothing capacitor between the devices; And a first semiconductor circuit breaker for interrupting current with a semiconductor element between the first semiconductor breaker and the anode terminal of the smoothing capacitor.

Further, the first semiconductor circuit breaker has means for operating to suppress an inrush current when charging the smoothing capacitor with a DC power supply and to operate to cut off a DC current flowing through the DC reactor. It is characterized by having.

Further, when the operation of the power converter is stopped,
Alternatively, when the first semiconductor circuit breaker is turned off, the second semiconductor cut-off including a semiconductor element in which a diode is connected in parallel with a reverse polarity in the above configuration so that energy stored in the DC reactor is consumed by the resistor. Or a series body in which a resistor and a resistor are connected in series, or connected in parallel between a connection point between the DC reactor and the first semiconductor circuit breaker and a cathode terminal of the smoothing capacitor, or an anode terminal of the smoothing capacitor. It is characterized in that it is connected in parallel between the cathode terminals.

[0011]

Embodiments of the present invention will be described below.

FIG. 1 shows the configuration of a basic shutoff system according to the present invention. The configuration includes a DC breaker 2, a DC reactor 3, which mechanically cuts off current between an inverter 5 (one of power converters) which receives DC power from a DC power supply 1 and converts DC into AC. An electrical connection circuit in the order of the semiconductor circuit breaker 10 and the smoothing capacitor 4 is interposed.
Here, the semiconductor circuit breaker 10 serves to suppress the inrush current when charging the smoothing capacitor 4 with the DC power supply 1 and also serves to cut off the DC current flowing through the DC reactor 3.

FIG. 2 shows one unit of semiconductor used for the semiconductor circuit breaker. The impedance from the upper side to the lower side in the figure can be controlled by controlling the gate of the semiconductor element, and a diode is connected in the reverse direction. I have.
The semiconductor and the diode that can be controlled by these gates may use different elements, or a composite element in which these two semiconductors are housed in one package. Further, a module type having a structure in which an insulator is interposed between a semiconductor and a heat radiation surface that dissipates heat generated in the semiconductor may be used.

FIGS. 3 and 4 show examples in which two semiconductors of one unit shown in FIG. 2 are used to constitute a semiconductor circuit breaker. The semiconductor circuit breaker 113 functions to suppress an inrush current when charging the smoothing capacitor 4, and is always supplied with an ON signal after charging is completed, thereby supplying a current from the DC power supply 1 to the inverter 5. When charging the smoothing capacitor 4, the rush current can be suppressed by repeatedly turning on and off the semiconductor circuit breaker 113 in small steps. The function of the semiconductor circuit breaker 112 and the resistor 115 is that the resistor 115 consumes Ｌ LI ² of energy due to the DC current flowing from the DC power supply 1 to the inverter 5 in the DC reactor 3. Specifically, when the operation of the inverter 5 is stopped, the current flowing in the DC reactor 3 flows into the smoothing capacitor 4 to increase the voltage of the smoothing capacitor.
In order to prevent the voltage of the smoothing capacitor from increasing, the semiconductor breaker 112 is turned on for a certain time when the operation of the inverter 5 is stopped. The semiconductor circuit breaker 113 is turned off when the current flowing through the smoothing reactor 3 becomes sufficiently small after the semiconductor circuit breaker 112 has been turned on for a certain period of time.

The difference between FIGS. 3 and 4 is whether the series body of the semiconductor circuit breaker 4 and the resistor 115 is connected to the left side or the right side of the semiconductor circuit breaker 113. Since the semiconductor circuit breaker 113 is turned off after the semiconductor circuit breaker 112 is turned off, when the semiconductor circuit breaker 112 is turned on for a certain period of time, the semiconductor circuit breaker 113 is in a conductive state. Even if it does, the electrical operation does not change.

FIGS. 5 and 6 show the semiconductor breaker 113 in FIGS. 3 and 4 (the semiconductor breaker 111 in FIGS. 5 and 6).
Is equivalent to 4) shows a case where the limiting resistor 116 for charging the smoothing capacitor 4 is connected in parallel.

The semiconductor circuit breaker 111 shown in FIG. 1 is turned off when charging the smoothing capacitor, and is supplied with an on signal after the charging of the smoothing capacitor is completed, and supplies a current from the DC power supply 1 to the inverter 5. The functions of the semiconductor breaker 112 and the resistor 115 are the same as those described with reference to FIGS.

In FIG. 5 and FIG.
Even if 1 is turned off, the smoothing capacitor 4 is charged by the DC power supply 1 by the resistor 116 connected in parallel. FIGS. 7 and 8 show a case where the semiconductor circuit breaker 113 is connected for the purpose of cutting off the charging path.

FIGS. 9 and 10 show a case where a semiconductor circuit breaker 114 is connected in series to the semiconductor circuit breaker 113 shown in FIGS. 7 and 8. FIG. Semiconductor breaker 113 and semiconductor breaker 114
Are connected in opposite polarities. Semiconductor breaker 114
Functions to prevent the energy stored in the smoothing capacitor 4 from flowing out to the power supply side when the DC power supply 1 has a short-circuit failure.

FIG. 11 shows a case where a voltage absorbing element for absorbing overvoltage is connected between the cathode terminal of the DC reactor 3 and the cathode terminal of the smoothing capacitor 4. This voltage absorbing element is used when the lightning strike occurs in the DC power supply
This is to prevent overvoltage from occurring at 11, 112, 113 and 114. As the voltage absorbing element, a non-linear discharge element or a series body of a capacitor and a resistor can be considered. FIG.
1 shows the case where the voltage absorbing element is connected to FIG. 5, but the same effect can be obtained by applying to FIG. 3 to FIG.

FIG. 12 shows the operation of the semiconductor circuit breakers 111 and 112 in FIGS. 5 and 6 when the current is cut off. The semiconductor circuit breaker 111 is turned off simultaneously with the start of the circuit break. Although not shown here, all the semiconductors of the inverter 5 are also turned off. The semiconductor circuit breaker 112 is turned on simultaneously with or immediately before the semiconductor circuit breaker 111 is turned off. Semiconductor breaker 1
The reason for turning on 12 is that the energy of 1 / 2LI ² stored in the DC reactor 3 is connected to the resistor 11 as described above.
5 for consumption.

FIG. 13 shows the operation of the semiconductor circuit breakers 111, 112, 113 and 114 in FIGS. 7 to 10 when the current is cut off. The operations of the semiconductor circuit breakers 111 and 112 are the same as in FIG. Semiconductor breakers 113, 114
Turns off after the currents flowing through the DC reactor 3 become sufficiently small after the semiconductor circuit breakers 111 and 112 are both turned off and the transient phenomenon is settled.

Here, the operation of the semiconductor circuit breaker will be described with a specific example. FIG. 16 illustrates an example of a calculation result when the operation illustrated in FIG. 12 is performed in the circuit illustrated in FIG. 5. The calculation conditions are described below.

The voltage of the DC power supply 1 is 1500 V. The current of the DC reactor before current interruption is 300 A. The inductance of the DC reactor is 23 mH. The resistance value of the resistor 115 is 20 Ω. The resistance value of the resistor 116 is 6 Ω. 4: 3 mF ・ Voltage before current cutoff of smoothing capacitor: 1500 V FIG. 14 shows that at time 0, semiconductor breaker 111 is turned off and semiconductor breaker 112 is turned on at the same time, then 20 m
This is a calculation example in which the semiconductor circuit breaker 112 is turned off after S. As can be seen from this result, even if the current of 300 A is cut off, the rise in the voltage of the smoothing capacitor 4 is at most about 180 V. By turning on the semiconductor circuit breaker 112, the energy of ＬLI ² stored in the DC reactor 3 is consumed by the resistor 115, so that the voltage rise of the smoothing capacitor 4 can be reduced. Incidentally, when the action of turning on the semiconductor circuit breaker 112 was not involved, the smoothing capacitor voltage was 300 A × √ (23 mH / 3 mF).
= 830V, and the smoothing capacitor voltage rises by 830V and rises to 2340V at the peak.

Next, FIGS. 15A and 15B show attachment portions of sensors for detecting voltages and currents of various parts in controlling the semiconductor circuit breaker. A voltage detector 118 for detecting the voltage of the DC power supply 1, a voltage detector 119 for detecting the voltage of the smoothing capacitor, a current detector 120 for detecting a current flowing through the smoothing reactor 3, and a current flowing through the semiconductor breaker 112 Is connected to each part.

FIG. 16 shows that the semiconductor circuit breaker 111 is turned off when the current flowing through the smoothing reactor 3 is detected by the current detector 120 and exceeds a certain value.

FIG. 17 shows the operation during the initial charging of the smoothing capacitor 4. First, FIGS. 5 and 6
In the case of, charging is started by turning on the mechanical DC circuit breaker 2, and in the case of FIGS. 7 to 10, the mechanical DC circuit breaker 2 is turned on, and then the semiconductor circuit breaker 11 is turned on.
By turning on 3,114, charging is started.
The voltage of the smoothing capacitor 4 is detected by the voltage detector 119 and the semiconductor circuit breaker 111 is turned on after sufficiently settling.

FIG. 18 shows a method of detecting a failure of the semiconductor circuit breaker 112. When the semiconductor circuit breaker 112 is off,
When the output of the current detector 121 exceeds 10 A, the semiconductor circuit breaker 112 is determined to be faulty, and the voltage of the smoothing capacitor 4 is 100
If the output of the current detector 121 is 10 A or less even though the voltage exceeds 0 V, it is determined that the semiconductor breaker 112 has failed.

FIGS. 19 and 20 show a method of detecting a failure of the semiconductor circuit breaker 111. FIG. FIG. 19 shows the semiconductor circuit breaker 11
1 shows a transient phenomenon at the time of initial charging of the smoothing capacitor 4 when a short-circuit failure occurs in 1. The charging of the smoothing capacitor 4 is started by turning on the mechanical DC circuit breaker 2 or turning on the semiconductor circuit breakers 113 and 114. When the semiconductor circuit breaker 111 is short-circuited, the smoothing capacitor voltage is changed to the power supply. It becomes an oscillating waveform exceeding the voltage. When the smoothing capacitor voltage exceeds the DC power supply voltage by a certain value or more during the charging operation of the smoothing capacitor 4, it can be determined that the semiconductor circuit breaker 111 has failed.

FIG. 20 shows the failure detection logic of the semiconductor circuit breaker 111. When charging is started by turning on the mechanical breaker 2 or turning on the semiconductor breakers 113 and 114, if the voltage of the smoothing capacitor 4 exceeds the voltage of the DC power supply 1 by 200 V or more within 100 ms thereafter, the semiconductor breaker 11
1 is determined to have failed.

FIG. 21 shows a case where the failure detection of the semiconductor circuit breaker 111 or the semiconductor circuit breaker 112 has been activated, or the case where a current of 400 A which exceeds a current value 300 A of a level at which the semiconductor circuit breaker breaks flows. Shows the logic for protecting by turning off the direct current circuit breaker 2.

FIG. 22 shows a specific logical design of the start / stop control of the semiconductor shut-off circuit and the power converter shown in FIGS.
This embodiment shows a case where the semiconductor circuit breaker 112 is turned on to discharge the voltage of the smoothing capacitor 4 when protection against an overvoltage is required beyond the voltage of the first embodiment. Hereinafter, this embodiment will be described. The ON state determination of the semiconductor circuit breaker 111 outputs “1” when the semiconductor circuit breaker 111 is on, and outputs “0” when it is off.
The determination of the ON state of the semiconductor breaker 112 is based on the semiconductor breaker 1
It outputs "1" when 12 is on and outputs "0" when it is off. The semiconductor breaker 111 ON command is
When the input is “1”, the semiconductor breaker 111 is turned on,
Turns off when "0". In the power converter start, the inverter 5 starts when the input is “1” and stops when the input is “0”. The ON command of the semiconductor circuit breaker 112 turns on the semiconductor circuit breaker 112 when the input is “1” and turns off when the input is “0”. First, when the power converter start command changes from “0” to “1” to start the power converter, the voltage of the smoothing capacitor 4 does not exceed 1900 V, and both the semiconductor circuit breakers 111 and 112 are turned off. The output of the AND gate 61 is "1"
Becomes The function of the OR gate 62 is as follows.
When the output of “0” becomes “0”, the semiconductor circuit breakers 111 and 112
Keeps the output of the AND gate 61 at "0" until both are turned off. AND gate 61
Becomes "1", the on-delay timer 64, AN
After 100 mS due to the operation of the D gate 65, the output of the OR gate 66 becomes "1" because the difference between the voltage of the smoothing capacitor 4 and the voltage of the DC power supply 1 is ± 100 V or less. When the output of the AND gate 61 is "1" and the semiconductor circuit breaker 112 is off by the AND gate 67 and the output of the OR gate 66 is "1", an ON command is output to the semiconductor circuit breaker 111, and at the same time, the power converter Start. This logic is the completion of charging of the smoothing capacitor 4. Next, when the voltage of the smoothing capacitor 4 exceeds 1900 V or the power converter start command becomes “0”, the output of the AND gate 61 becomes “0”. When the output of the AND gate 61 becomes “0”, the output of the AND gate 67 becomes “0”, the semiconductor circuit breaker 111 is turned off, and the power converter stops. It is determined by the one-shot timer 68, the AND gate 69, and the OR gate 70 whether to stop the power converter and turn on the semiconductor circuit breaker 112 at the same time. When the voltage of the smoothing capacitor 4 exceeds 1900 V, the semiconductor breaker 112 is unconditionally turned on by the OR gate 71. In addition, 1 m from when the output of the AND gate 61 changes to “0”
The current flowing in the DC reactor 3 during S is the current detector 1
More than 100A detected by 20 or -100A
The semiconductor circuit breaker 112 is also turned on in the following cases. The reason for adding this logic is that if the current flowing through the DC reactor 3 when the power converter is stopped is sufficiently small, it is not necessary to turn on the semiconductor circuit breaker 112 because the voltage rise of the smoothing capacitor 4 is low. That's why.
If the current flowing through the DC reactor is 100 A or less, the rise of the smoothing capacitor voltage is 100 A × √ (23 m
H / 3mF) = 276V, which is sufficiently small. Once the semiconductor circuit breaker 112 is turned on, the difference between the voltage of the smoothing capacitor 4 and the voltage of the DC power supply 1 is within 100 V and the current flowing through the DC reactor 3 is ± 100 due to the operation of the one-shot timer 72 and the AND gate 73.
A and the condition that at least 20 mS has elapsed since the semiconductor breaker 112 was turned on.
12 is turned off. Here, it goes without saying that the output of the AND gate 67 may be fed back instead of the output of the ON state determination of the semiconductor circuit breaker 111, and the output of the SR flip-flop 71 may be fed back instead of the output of the ON state determination of the semiconductor circuit breaker 112.

FIG. 23 shows a specific logical design of the semiconductor cutoff circuit and the start / stop control of the power converter shown in FIGS. 7 to 10, and the case where the voltage of the smoothing capacitor 4 exceeds the voltage of the DC power supply 1 This embodiment shows a case where the semiconductor circuit breaker 112 is turned on to discharge the voltage of the smoothing capacitor 4 when protection is required.

This embodiment will be described below. The ON state determination of the semiconductor circuit breaker 111 outputs “1” when the semiconductor circuit breaker 111 is on, and outputs “0” when it is off. The ON state determination of the semiconductor circuit breaker 112 outputs “1” when the semiconductor circuit breaker 112 is on, and outputs “0” when it is off. Semiconductor circuit breaker 113,
The determination of the ON state of 114 is performed by the semiconductor circuit breakers 113 and 114.
Outputs “1” when both are on, and outputs “0” when both are off. The semiconductor breaker 111 ON command turns on the semiconductor breaker 111 when the input is “1”,
Turns off when "0". In the power converter start, the inverter 5 starts when the input is “1” and stops when the input is “0”. The ON command for the semiconductor circuit breakers 113 and 114 turns on both the semiconductor circuit breakers 113 and 114 when the input is “1” and turns off when the input is “0”. Semiconductor breaker 1
When the input is "1", the semiconductor breaker 1
12 is turned on, and turned off when it is "0". First, when the power converter start command changes from "0" to "1" to start the power converter, it is determined that the voltage of the smoothing capacitor 4 does not exceed 1900 V and the semiconductor circuit breaker 11
The output of the AND gate 81 becomes "1" on condition that all of the elements 1, 112, 113 and 114 are off. OR
The function of the gate 82 is that once the output of the AND gate 80 becomes "0", the semiconductor circuit breakers 111, 112, 113,
The function of holding the output of the AND gate 81 at "0" until both 114 are turned off. When the outputs of the AND gate 81 and the AND gate 85 are both "1" by the operation of the AND gate 83, the semiconductor circuit breaker 113,
114 is turned on. At this point, charging of the smoothing capacitor 4 is started. When the output of the ON state determination of the semiconductor circuit breakers 113 and 114 becomes "1", the on-delay timers 88 and A
After 100 mS due to the operation of the ND gate 89, the difference between the voltage of the smoothing capacitor 4 and the voltage of the DC power supply 1 is ± 100 V
The output of the OR gate 90 is "1" because
Becomes When the output of the AND gate 81 is "1" and the semiconductor circuit breaker 112 is off by the AND gate 91 and the output of the OR gate 90 is "1", an ON command is output to the semiconductor circuit breaker 111, and at the same time, the power converter Start. This logic is the completion of charging of the smoothing capacitor 4. Next, when the voltage of the smoothing capacitor 4 exceeds 1900 V or the power converter start command becomes “0”, the output of the AND gate 81 becomes “0”. When the output of the AND gate 81 becomes "0", the output of the AND gate 91 becomes "0", the semiconductor circuit breaker 111 is turned off, and the power converter stops. The one-shot timer 92, AND gate 93, and O are used to determine whether to turn on the semiconductor circuit breaker 112 at the same time as stopping the power converter.
Determined by R gate 94. When the voltage of the smoothing capacitor 4 exceeds 1900 V, the semiconductor breaker 112 is unconditionally turned on by the OR gate 94. In addition, the current flowing through the DC reactor 3 within 1 ms from the time when the output of the AND gate 81 changes to "0" is detected by the current detector 120, and a current of 100 A or more or -10
Also in the case of 0 A or less, the semiconductor circuit breaker 112 is turned on.
The reason for adding this logic is that if the current flowing through the DC reactor 3 when the power converter is stopped is sufficiently small, it is not necessary to turn on the semiconductor circuit breaker 112 because the voltage rise of the smoothing capacitor 4 is low. That's why. If the current flowing through the DC reactor is 100 A or less, the rise in the smoothing capacitor voltage is 100 A × √ (2
3mH / 3mF) = 276V, which is sufficiently small. Once the semiconductor circuit breaker 112 is turned on, the difference between the voltage of the smoothing capacitor 4 and the voltage of the DC power supply 1 is 100 V by the operation of the one-shot timer 97 and the AND gate 96.
Current within ± 100A within DC reactor 3
Within 2 seconds since the semiconductor circuit breaker 112 was turned on.
Semiconductor breaker 11 on condition that 0 ms or more has passed.
2 is turned off. Next, by the operation of the AND gate 87, the output of the AND gate 81 is "0" and the semiconductor breaker 1
When both 11 and 112 are off and the condition that the current flowing through DC reactor 3 is ± 10 A or less is satisfied, semiconductor circuit breakers 113 and 114 are turned off, and a series of operations is completed. Here, the output of the AND gate 91 is used instead of the ON state determination output of the semiconductor circuit breaker 111, the output of the SR flip-flop 95 is used instead of the ON state determination output of the semiconductor circuit breaker 112, and the ON state of the semiconductor circuit breakers 113 and 114 is set. It goes without saying that the output of the flip-flop 84 may be fed back instead of the discrimination output.

FIG. 24 is a circuit diagram showing semiconductor elements 51 to 56 and three-phase load 6 constituting inverter 5 in the circuit shown in FIG.

FIG. 25 shows the semiconductor circuit breaker 11 shown in FIG.
This is an embodiment in which semiconductor elements 51 to 56 constituting the inverter 5 are mounted on a common cooling device. This diagram shows the circuit shown in FIG. 8, but it is needless to say that the present invention can be applied to all the circuits shown in FIGS. By sharing the cooling device, the size and cost of the device can be reduced.

FIG. 26 shows a case where the mechanical DC circuit breaker 2 is shared by a plurality of semiconductor circuit breakers and the inverter 5.
Openers 7a, 7 for opening each power converter
This is an example in which b is added. If the power converter breaks down, it becomes possible to separate it from the DC power supply individually by the opener 7, and the redundancy of the system is improved. The opener 7 does not need to have the ability to interrupt the current. If the power converter breaks down, first, the mechanical DC breaker 2 is turned off, and in that state, the opener is turned off.
This is because there is no need to interrupt the current.

[0038]

According to the present invention, by using a semiconductor breaker instead of a high-speed breaker as a cut-off system of a power conversion device, a smoothing capacitor can be initialized before starting an inverter in addition to a function of cutting off current. By providing a function of suppressing an inrush current at the time of charging, cost reduction and maintenance can be saved. In addition, when the circuit breaker is turned off (opened) due to an overcurrent or when the operation of the inverter is stopped, the problem that the smoothing capacitor is overcharged by the energy of the DC reactor generated by the transient phenomenon can be solved. is there.

[Brief description of the drawings]

FIG. 1 shows a configuration of a basic shutoff system of a power converter of the present invention.

FIG. 2 is a configuration diagram of one unit of the semiconductor circuit breaker in FIG. 1;

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

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

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

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

FIG. 7 is a configuration diagram showing another embodiment of the present invention.

FIG. 8 is a configuration diagram showing another embodiment of the present invention.

FIG. 9 is a configuration diagram showing another embodiment of the present invention.

FIG. 10 is a configuration diagram showing another embodiment of the present invention.

FIG. 11 is a configuration diagram showing another embodiment of the present invention.

FIG. 12 is a time sequence at the time of operation in the embodiment of the present invention.

FIG. 13 is a time sequence at the time of operation in the embodiment of the present invention.

FIG. 14 shows a calculation example of a transient phenomenon at the time of current interruption in the present invention.

FIG. 15 is a diagram showing voltage / current detection points of each part of the semiconductor cutoff circuit in practicing the present invention.

FIG. 16 is an embodiment in which the semiconductor circuit breaker is turned off when the current of the DC reactor exceeds a certain value according to the present invention.

FIG. 17 is a time sequence at the time of charging a smoothing capacitor in the present invention.

FIG. 18 is a failure detection logic circuit diagram of the semiconductor circuit breaker 112 of the present invention.

FIG. 19 is a time sequence at the time of failure of the semiconductor circuit breaker 111 of the present invention.

FIG. 20 is a failure detection logic circuit diagram of the semiconductor circuit breaker 111 of the present invention.

FIG. 21 is a logic diagram for turning off the mechanical DC circuit breaker 2 of the present invention.

FIG. 22 is a logic circuit diagram for protecting the overvoltage of the smoothing capacitor of the present invention by turning on the semiconductor circuit breaker 112.

FIG. 23 is a logic circuit diagram for protecting the overvoltage of the smoothing capacitor of the present invention by turning on the semiconductor circuit breaker 112.

FIG. 24 shows an embodiment in which a cooling device for a semiconductor breaker and a cooling device for a semiconductor element constituting an inverter are shared.

FIG. 25 shows an embodiment in which a cooling device for a semiconductor breaker and a cooling device for a semiconductor element constituting an inverter are shared.

FIG. 26 is an embodiment of a circuit system when a plurality of power converters of the present invention are shared by one mechanical DC breaker.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 DC power supply 2 Mechanical DC breaker 3 DC reactor 4 Smoothing capacitor 5 Inverter 10 Semiconductor breaker 11 Unit of semiconductor breaker 111, 1
12, 113, 114 ... semiconductor breaker, 115, 116
... Resistors, 117, voltage absorbing elements, 118, 119, voltage detectors, 120, 121, current detectors, 200, semiconductor cooling devices.

Claims (22)

[Claims] 1. A shut-off system for a power converter that receives a supply of power from a DC power supply and converts a DC voltage into an AC voltage. A filter circuit comprising at least a DC reactor and a smoothing capacitor between the DC power supply and the power converter. A DC breaker that mechanically cuts off the current supplied from the DC power supply between the DC power supply point and the DC reactor, between the DC reactor and the anode terminal of the smoothing capacitor. And a first semiconductor circuit breaker for interrupting a current with a semiconductor element. 2. The first semiconductor circuit breaker according to claim 1, wherein the first semiconductor circuit breaker can control the impedance from one side to the other side by a semiconductor switch, and has a function of limiting current by being connected in a reverse direction by a diode or the like. A shut-off system for a power converter, wherein the shut-off system is not provided, and at least the semiconductor is constituted by one or more sets. 3. The circuit according to claim 2, wherein the first semiconductor circuit breaker operates to suppress an inrush current when the smoothing capacitor is charged by the DC power supply, and cuts off a DC current flowing through the DC reactor. A shut-off system for a power converter, comprising: means for operating the power converter. 4. A device according to claim 1, further comprising means for consuming energy stored in said DC reactor through a resistor when said power converter is stopped or when said first semiconductor circuit breaker is turned off. A shut-off system for a power converter. 5. The DC reactor and the first semiconductor according to claim 4, wherein a series body in which a diode and a resistor are connected in series is composed of a semiconductor element in which diodes are connected in parallel with opposite polarities. A shutoff system for a power converter, wherein the shutoff system is connected in parallel between a connection point with a circuit breaker and a cathode terminal of the smoothing capacitor, or is connected in parallel between an anode terminal and a cathode terminal of the smoothing capacitor. 6. A power converter according to claim 5, wherein a resistor is connected in parallel with said first semiconductor circuit breaker. 7. A semiconductor device according to claim 6, wherein a diode is connected in parallel between the first semiconductor breaker, the second semiconductor breaker, and a resistor in series. 3. A shut-off system for a power converter, wherein at least one semiconductor shut-off device according to claim 3 is interposed. 8. A semiconductor device according to claim 6, wherein a diode is connected in parallel with a reverse polarity between a connection point of a series body of said first semiconductor breaker, said second semiconductor breaker and a resistor. A shut-off system for a power converter, wherein two shut-off devices are interposed (third and fourth semiconductor shut-off devices), and the two semiconductor shut-off devices are connected in series with opposite polarities. 9. A voltage absorbing element such as a non-linear discharge element or a series body of a capacitor and a resistor between a cathode terminal of the DC reactor and a cathode terminal of the smoothing capacitor. And a shutoff system for the power converter. 10. The circuit according to claim 6, wherein when the first semiconductor circuit breaker interrupts current, the second semiconductor circuit breaker is turned on (closed) and turned off (opened) after a lapse of a predetermined time. A shutdown system for a power converter, comprising a sequence. 11. The power converter according to claim 10, wherein the first semiconductor circuit breaker has a sequence of turning off during or before turning on the second semiconductor circuit breaker. Isolation system. 12. The apparatus according to claim 8, wherein when the first semiconductor circuit breaker interrupts the current, the second semiconductor circuit breaker is turned on (closed) and turned off (opened) after a lapse of a predetermined time. And a sequence for turning off the third and fourth semiconductor circuit breakers thereafter. 13. A power converter according to claim 12, wherein said first semiconductor circuit breaker has a sequence of turning off during or before turning on said second semiconductor circuit breaker. Isolation system. 14. A device according to claim 6, further comprising means for detecting a current flowing in or out of said DC power supply, and when the current exceeds a predetermined value, the current is reduced by said first semiconductor circuit breaker. A shutoff system for a power converter, comprising a shutoff sequence. 15. The first semiconductor circuit breaker according to claim 6, wherein said first semiconductor circuit breaker is turned off when said smoothing capacitor is charged by said DC power supply, and said first semiconductor circuit breaker is charged after said smoothing capacitor is charged. A shut-off system for a power converter, comprising a sequence for turning on the power. 16. The method according to claim 8, wherein when charging the smoothing capacitor with the DC power supply, first, the third and fourth semiconductor circuit breakers are turned on, and the first semiconductor circuit breaker is turned off. A shut-off system for a power converter, comprising a sequence for turning on the first semiconductor breaker after the smoothing capacitor is charged. 17. The method according to claim 1, wherein when it is detected that a failure of the semiconductor circuit breaker or a failure of the power converter that cannot be restored occurs, the current is not turned off by the semiconductor circuit breaker. A shut-off system for a power converter, comprising: a sequence for turning off a current by the mechanical DC interrupter. 18. The apparatus according to claim 5, further comprising means for detecting a current flowing through said second semiconductor circuit breaker, wherein the current flows during an off-period of said second semiconductor circuit breaker. And a means for generating a failure signal indicating that the semiconductor circuit breaker has failed when the power supply device detects a failure. 19. A means according to claim 5, wherein a means for detecting a current flowing through said second semiconductor circuit breaker,
Means for detecting the smoothing capacitor voltage, and a current flows through the second semiconductor circuit breaker during the ON period of the second semiconductor circuit breaker, even though the smoothing capacitor voltage is equal to or higher than a certain value. And a means for generating a failure signal indicating that the second semiconductor circuit breaker has failed in the absence of the failure. 20. The apparatus according to claim 1, further comprising: means for detecting a voltage of the DC power supply; and means for detecting a voltage of the smoothing capacitor, wherein the smoothing capacitor is charged when the smoothing capacitor is charged. An interrupting system for a power converter, comprising: means for generating a failure signal indicating that the first semiconductor interrupter has failed when a capacitor voltage rises by a certain value or more than a DC power supply voltage. 21. A device according to claim 5, further comprising means for detecting a voltage of said smoothing capacitor, wherein when said voltage reaches a predetermined value, said second semiconductor circuit breaker is turned on to smooth the voltage. A shut-off system for a power converter, comprising: means for discharging a capacitor voltage. 22. The shut-off of a power converter, wherein the semiconductor circuit breaker according to any one of claims 1 to 8 is installed in a cooling device that cools the power converter that converts direct current into alternating current. system.