JPH0662582A - Three-level inverter - Google Patents

Abstract

PURPOSE:To shorten the time to reset a transformer by reducing the dielectric strength of a capacitor to recover energy accumulated in a snubber circuit, by enhancing the efficiency of energy recovery, and by enabling a plurality of phases to share recovery capacitors and energy recovery circuits. CONSTITUTION:Recovery capacitors 9A,9B are connected between nodes of snubber diodes 6A-6D and snubber diodes. 5A-5D connected in parallel to GTO 1A-1D of positive and negative arms and positive and negative side buses, energies extracted from these recovery capacitors 9A, 9B are recovered by energy regenerative circuits E1, E2 to DC power sources 4A, 4B divided by intermediate potential points. Rectification circuits 29A, 29B are connected between intermediate potential points 0 on the secondary side of each transformer 26A, 26B and the positive side or negative side of each DC power source 4A, 4B, so that the time to reset a transformer can be shortened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-level inverter device constructed by using a self-arc-extinguishing type semiconductor element.

[0002]

2. Description of the Related Art The basic structure of a conventional three-level inverter device is disclosed in Japanese Patent Laid-Open No. 55-43996.
The self-arc-extinguishing type semiconductor element that constitutes this three-level inverter device has a limitation in the voltage increase rate and the current increase rate, for example, a GTO thyristor (hereinafter abbreviated as GTO)
When applying, a snubber circuit is required.

FIGS. 20 and 21 show, for example, Japanese Patent Laid-Open No. 1-1.
FIG. 1 is a circuit diagram showing a conventional three-level inverter device provided with a means for regenerating energy stored in the snubber circuit to a DC power source as disclosed in Japanese Patent Publication No. 98280, where 1A, 1B, 1C and 1D are It is a self-arc-extinguishing type semiconductor element, and these self-arc-extinguishing type semiconductor elements 1A, 1B, 1
GTO is applied as an example of C and 1D.

2A, 2B, 2C and 2D are GTO 1A and 1
Free-wheel diodes 3A and 3B are anti-parallel connected to B, 1C and 1D, and clamp diodes 4A and 4B.
Is a DC power supply divided by an intermediate potential point O, where the positive side of the DC bus is P and the negative side is N.

Further, 5A, 5B, 5C and 5D are snubber capacitors, 6A, 6B, 6C and 6D are snubber diodes, which form a snubber circuit. 7A and 7B are anode reactors, 9A and 9B are recovery capacitors for recovering stored energy of each anode reactor via diodes 8A and 8B, 10A and 10B are switches, and 11
A and 11B are diodes, and 12A and 12B are reactors, which respectively constitute one step-down chopper.

Next, the operation will be described. Each GTO 1A-1D
For example, in the case of GTO 1A, the voltage increase rate is suppressed by the snubber circuit including the snubber capacitor 5A and the snubber diode 6A. The same applies to the other GTOs 1B to 1D.

Regarding the current increase rate, the current increase rate applied to the GTOs 1A and 1C by the anode reactor 7A is the same as the current increase rate applied to the GTOs 1B and 1D by the anode reactor 7B.
The rate of increase in current applied to each is suppressed.

In this three-level inverter device,
The energy stored in the snubber capacitor 5A and the anode reactor 7A is recovered by the recovery capacitor 9A via the diode 8A, and the energy stored in the snubber capacitor 5D and the anode reactor 7B is recovered by the diode 8A.
It is recovered to the recovery condenser 9B via B.

Here, the recovery capacitors 9A and 9B are charged to preferably higher values than the voltage values of the DC power supplies 4A and 4B. This overcharge voltage is the anode reactor 7
It is necessary to quickly recover the energy stored in A and 7B to the recovery capacitors 9A and 9B.

The excess energy recovered by the recovery capacitor 9A is generated by the switch 10A, diode 11A,
A known step-down chopper composed of the reactor 12A is used as the energy regeneration circuit E to be regenerated by the DC power supply 4A. The same applies to the recovery capacitor 9B.

The energy stored in the snubber capacitors 5B and 5C is consumed by the discharge resistor 13. FIG. 21 is a diagram in which the discharge resistor 13 that consumes the energy is replaced with a transformer 14 and a diode 15 in consideration of energy regeneration between the PN of the DC power source. In addition, 16 is a transformer 14
Is the reset resistance of.

[0012]

Since the conventional three-level inverter device is constructed as described above, the withstanding voltage of the recovery capacitors 9A, 9B must be equal to or higher than the voltage value of the divided DC power supplies 4A, 4B. Therefore, there has been a problem that the recovery capacitors 9A and 9B are enlarged.

Further, the energy accumulated in the snubber capacitors 5B and 5D is consumed by the discharge resistor 13,
In addition to the decrease in efficiency, in the case of Fig. 21 in which the discharge resistance 13 is replaced with the transformer 4 for regeneration, there is a problem that the reset time of the transformer 14 becomes long. This is because the reset voltage is limited to the voltage drop that occurs in the snubber diode 6B and the reset resistor 16.

Further, since the voltage between the PNs of the DC power supplies 4A and 4B is applied to the secondary side of the transformer 14, the transformer 14
Becomes larger, and the withstand voltage of the diode 15 forming the rectifier circuit connected to the secondary side of the transformer 14 needs to be higher than the voltage between PN. According to the voltage value between PN, the diode 15 is connected in series. There was a problem that it had to be used.

The invention of claim 1 is to solve the above problems, and it is possible to reduce the breakdown voltage of the capacitor for recovering the energy accumulated in the snubber capacitor and the anode reactor. The purpose is to obtain a level inverter device.

It is an object of the present invention to provide a three-level inverter device capable of recovering the energy consumed by the discharge resistance in the recovery capacitor.

It is an object of the invention of claim 3 to obtain a three-level inverter device capable of simplifying the configuration and reducing the cost by sharing the recovery capacitor and the energy regenerating circuit with a plurality of phases.

It is an object of the invention of claim 4 to obtain a three-level inverter device capable of recovering the energy accumulated in all of the snubber capacitor and the anode reactor by adding two recovery capacitors to the intermediate potential point.

According to a fifth aspect of the present invention, a first to fourth recovery capacitors and first to fourth energy recovery circuits are shared by a plurality of phases to obtain a three-level inverter device capable of simplifying the configuration and reducing the cost. With the goal.

It is an object of the present invention to provide a three-level inverter device capable of shortening the reset time of the transformer and reducing the breakdown voltage of the components of the device below the voltage across the PN of the DC power supply.

[0021]

[Means for Solving the Problems] 3 according to the invention of claim 1
The level inverter device is a snubber in which a reactor connected in series to the self-arc-extinguishing type semiconductor elements forming each of the positive and negative arms, a snubber diode and a snubber capacitor connected in parallel to each of the self-extinguishing type semiconductor elements are connected in series. A circuit, a discharge resistor connected in parallel between respective connection points of a snubber diode and a snubber capacitor, which are connected in parallel to the second and third self-extinguishing semiconductor elements to form one of the snubber circuits, and Connected to the self-extinguishing type semiconductor element of the above-mentioned snubber circuit and a snubber diode and a snubber capacitor, the first diode and the first recovery capacitor connecting the positive side bus and the connection point, and the fourth self-extinguishing capacitor. Connect the connection point of the snubber diode and snubber capacitor that are connected in parallel to the arc-shaped semiconductor element to form the snubber circuit and the negative side bus And a second diode and a second recovery capacitor that, the first energy recovery circuit,
Energy is extracted from the first recovery capacitor and regenerated to the positive side of the DC power supply divided at the intermediate potential point, and a second energy recovery circuit is caused to extract energy from the second recovery capacitor. , Is regenerated on the negative side of the DC power supply divided at the intermediate potential point.

According to another aspect of the present invention, there is provided a three-level inverter device, wherein a reactor connected in series to the self-extinguishing type semiconductor elements forming each of the positive and negative arms and a snubber connected in parallel to each of the self-extinguishing type semiconductor elements. A snubber circuit in which a diode and a snubber capacitor are connected in series, and a connection point of a snubber diode and a snubber capacitor which are connected in parallel to the first self-arc-extinguishing type semiconductor element to form the snubber circuit and a positive bus are connected. First diode and first
Recovery capacitor, a second diode and a second recovery diode that are connected in parallel to the fourth self-arc-extinguishing semiconductor element to form the snubber circuit, and that connect the connection point of the snubber capacitor and the negative side bus bar. A capacitor,
A first series body composed of a capacitor, a diode, and an auxiliary reactor connected in parallel to the second self-arc-extinguishing semiconductor element and connected in parallel to a snubber diode forming the snubber circuit; and the first series body. A diode connecting the constituent capacitor to the first recovery capacitor;
A second series body composed of a capacitor, a diode, and an auxiliary reactor which are connected in parallel to a third self-arc-extinguishing type semiconductor device and are connected in parallel to a snubber diode forming the snubber circuit; The direct current divided by the intermediate potential point by causing the first energy regeneration circuit to extract energy from the first recovery capacitor, the direct current being provided with a diode that connects the constituent capacitor to the second recovery capacitor. Regeneration to the positive side of the power source, and causing the second energy regeneration circuit to take out energy from the second recovery capacitor to regenerate to the negative side of the DC power source divided at the intermediate potential point. Is.

A three-level inverter device according to a third aspect of the present invention includes first and second recovery capacitors, and first and second energy regenerative circuits connected to the first and second recovery capacitors, respectively. Is commonly connected for a plurality of phases.

According to a fourth aspect of the present invention, in a three-level inverter device, a reactor connected in series to the self-arc-extinguishing type semiconductor elements forming each of the positive and negative arms and a snubber connected in parallel to each of the self-extinguishing type semiconductor elements. A snubber circuit in which a diode and a snubber capacitor are connected in series, and a connection point of the snubber diode and the snubber capacitor, which are connected in parallel to the first self-arc-extinguishing type semiconductor element to form the snubber circuit, and a positive bus are connected. A first diode and a first recovery capacitor connected to the fourth self-arc-extinguishing semiconductor element in parallel to form the snubber circuit, and connecting the connection point of the snubber diode and the snubber capacitor to the negative side bus bar. The second snubber circuit is connected in parallel with the second diode and the second recovery capacitor, and the second self-extinguishing semiconductor element. Connected in series with an auxiliary switch, a reactor, a diode and a third recovery capacitor that connect the connection point of the snubber diode and the snubber capacitor to the intermediate potential point, and are connected in parallel to the third self-arc-extinguishing semiconductor element. And a snubber diode and a snubber capacitor that form the snubber circuit are connected to the intermediate potential point in series with an auxiliary switch, a reactor, a diode and a fourth recovery capacitor, and an energy regeneration circuit is provided. Energy is taken out from each of the first to fourth recovery capacitors and is regenerated to the positive side or the negative side of the DC power supply divided at the intermediate potential point.

A three-level inverter device according to a fifth aspect of the present invention is connected to the first, second, third and fourth recovery capacitors and the first, second, third and fourth recovery capacitors, respectively. The first, second, third and fourth energy regeneration circuits that have been operated are commonly connected for a plurality of phases.

According to a sixth aspect of the present invention, in a three-level inverter device, a reactor connected in series to the self-extinguishing type semiconductor element forming each of the positive and negative arms, and a snubber connected in parallel to each of the self-extinguishing type semiconductor elements. A snubber circuit in which a diode and a snubber capacitor are connected in series, and a connection point of the snubber diode and the snubber capacitor, which are connected to the first self-arc-extinguishing semiconductor element and constitute the snubber circuit, and a positive side busbar are connected. A second diode connecting the first diode and the first recovery capacitor, and a connection point of the snubber diode and the snubber capacitor, which are connected in parallel to the fourth self-arc-extinguishing type semiconductor element to form the snubber circuit, to the negative side busbar. Energy is extracted from each of the diode and the second recovery capacitor, and the first and second recovery capacitors, and the intermediate potential Of the snubber capacitor and the snubber diode, which are connected in parallel to the positive and negative side of the DC power supply divided by A primary side of a transformer or an auxiliary switch that individually connects the connection point and the output terminal or the intermediate potential point to each other via a common reactor, and a rectifying circuit is provided on the secondary side of each of the transformers. It is connected between the intermediate potential point and the positive or negative side of the DC power supply.

[0027]

The recovery capacitor according to the invention of claim 1 is connected to the P side and the N side of the DC bus of the DC power source,
The charging voltage value of this recovery capacitor is reduced so that the withstand voltage can be reduced.

The recovery capacitor according to the second aspect of the present invention makes it possible to recover the energy consumed by the discharge resistance.

The recovery capacitor and the energy regeneration circuit according to the invention of claim 3 can be shared by a plurality of phases.

The recovery capacitor added to the intermediate potential point in the invention of claim 4 recovers the energy accumulated in all of the snubber capacitor for the self-extinguishing type semiconductor element and the anode reactor to be regenerated to the DC power supply. .

The first to fourth recovery capacitors and the first to fourth energy recovery circuits in the fifth aspect of the invention can be shared by a plurality of phases.

In the transformer according to the sixth aspect of the invention, by connecting an auxiliary switch for resetting the transformer to the primary side of the transformer, the speed of resetting the transformer is increased.

[0033]

EXAMPLES Example 1. An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, 1A, 1B, 1C,
1D is a GTO as a self-arc-extinguishing type semiconductor device, and in this embodiment, GTOs 1A, 1B and GTO1 are provided between the PNs of the positive and negative buses of the DC power supplies 4A, 4B having the intermediate potential point O.
C and 1D are connected as positive and negative arms.

2A, 2B, 2C and 2D are GTO1
Free wheel diodes connected in parallel to A, 1B, 1C and 1D, 3A is a clamp diode connected between the series connection point of GTO1A and GTO1B and the intermediate potential point O, 3B is a series connection of GTO1C and GTO1D A clamp diode connected between the point and the intermediate potential point O, and X is an output terminal as a connection point between the positive arm and the negative arm.

7A and 7B are anode reactors, 5A,
5B, 5C and 5D are snubber capacitors, 6A, 6B and 6
C and 6D are snubber diodes. For example, for GTO1A, snubber capacitor 5A and snubber diode 6A.
Are connected in series to form a snubber circuit, and the same applies to the other GTOs 1B, 1C and 1D. Reference numeral 13 is a discharge resistance common to the snubber capacitors 5B and 5C.

Reference numeral 9A denotes a recovery capacitor, which recovers the energy accumulated in the snubber capacitor 5A and the anode reactor 7A via the diode 8A. Similarly, for the recovery condenser 9B, the snubber condenser 5
Energy accumulated in D and the anode reactor 7B is recovered via the diode 8B.

A first energy regeneration circuit E for extracting energy from the recovery capacitor 9A and regenerating it to the DC power source 4A.
1 includes a switch 10A, a diode 11A, and a reactor 12A, and similarly for the recovery capacitor 9B, the second energy regeneration circuit E2 has the switch 1
0B, the diode 11B, and the reactor 12B, the energy of the recovery capacitor 9B is regenerated to the DC power supply 4B.

Here, the voltages of the DC power supplies 4A and 4B are each E, and the recovery capacitors 9A and 9B are charged to the voltage e with the side marked with a dot as positive, and the output terminal X has an inductive property (not shown). It is assumed that the load is connected and the vector of load current does not change during the switching operation of each GTO 1A-1D.

Next, the operation will be described. The paths of currents flowing through the above circuits are collectively shown in FIG. First, turn off GTO1A to change the output terminal voltage to 2E.
The circuit operation when changing from E to E will be described.

The positive arm GTOs 1A and 1B are on and the negative arm GTOs 1C and 1D are off. A load current is flowing from the output terminal X in the direction of the arrow in the figure by the path 41, and the snubber capacitors 5A and 5B are connected. The voltage is zero, the voltage of the snubber capacitor 5C is charged to the voltage E of the DC power supply 4A, and the voltage of the snubber capacitor 5D is charged to the sum of the voltage E of the DC power supply 4B and the voltage e of the recovery capacitor 9B. Consider a case where the GTO 1A is turned off from the state to cut off the load current and the GTO 1C is turned on after a certain short-circuit prevention time.

When the GTO 1A is turned off, the interrupted load current is bypassed to the path 42, so that the snubber capacitor 5A receives the voltage E of the DC power supply 4A and the recovery capacitor 9A.
The battery is charged to a voltage value that is the sum of the voltage e. At this time, the snubber capacitor 5A suppresses the voltage increase rate applied to the GTO 1A.

Immediately after that, energy is excessively accumulated in the anode reactor 7A, but all the energy is recovered by the recovery capacitor 9A through the path 43. Note that the point different from the conventional FIG. 20 is that the path 43 does not include the DC power supply 4A. Therefore, the charging voltage of the recovery capacitor 9A can be reduced.

When the GTO 1A is turned off and the GTO 1C is turned off after the short circuit prevention time, the snubber capacitor 5C is discharged to the voltage zero by the path 44. At this time, the rate of increase in current applied to the GTO 1C is suppressed by the discharge resistor 13, but the energy stored in the snubber capacitor 5B is consumed by the discharge resistor 13.

The charging voltage of the snubber capacitor 5A is the voltage E.
When the above is reached, the clamp diode 3A becomes conductive. Through this process, the load current flows through the path 45, and the output terminal voltage is changed to 2E by turning off the GTO 1A.
The circuit operation when changing from E to E ends.

Next, the circuit operation when the output terminal voltage is changed from E to 0 by turning off the GTO 1B will be described. The positive arm GTO1A is off, the GTO1B is on, the negative arm GTO1C is on, and the GTO1D is off. A load current is flowing to the output terminal X in the direction of the arrow in the figure by the path 45, and the snubber capacitors 5B and 5C. Are zero, the voltages of the snubber capacitors 5A and 5D are the voltage e of the DC power supplies 4A and 4B and the recovery capacitor 9A, respectively.
From the state of being charged to the voltage value of the sum of the voltage e of 9B, G
Consider a case where the TO1B is turned off to interrupt the load current and the GTO1D is turned on after a certain short-circuit prevention time.

When the GTO 1B is turned off, the interrupted load current is bypassed to the path 46 and the snubber capacitor 5B is charged to the voltage E of the DC power supply 4B. At this time, the snubber capacitor 5B suppresses the voltage increase rate applied to the GTO 1B.

When the GTO 1B is turned off and the GTO 1D is turned on after the short circuit prevention time, the snubber capacitor 5D is discharged to the voltage zero by the path 47, and the energy accumulated in the snubber capacitor 5D is recovered by the path 47 in the recovery capacitor 9B. To be done.

Immediately after that, energy is excessively accumulated in the anode reactor 7B, but all the energy is recovered by the recovery capacitor 9B by the path 48. In addition,
The difference from the conventional FIG. 20 is that the DC power supply 4B is not included in the paths 47 and 48.

Therefore, the charging voltage of the recovery capacitor 9B can be reduced. When the charging voltage of the snubber capacitor 5B becomes the voltage E, the freewheel diode 2
C and 2D are conducted. Through this process, the load current passes through path 4.
9, the circuit operation in the case of changing the output terminal voltage from E to 0 by turning off the GTO 1B ends.

Next, the circuit operation when the output terminal voltage is changed from 0 to E by turning off the GTO 1B will be described. The positive arm GTOs 1A and 1B are off, the negative arm GTOs 1C and 1D are on, and the load current flows from the output terminal X in the direction of the arrow in the figure by the path 49, and the voltages of the snubber capacitors 5C and 5D are respectively. Zero, the snubber capacitor 5A is the voltage E of the DC power source 4A and the recovery capacitor 9A.
From the state in which the snubber capacitor 5B is charged to the voltage E of the sum of the voltage e of A and the voltage E of the DC power supply 4B,
Consider a case where the GTO 1D is turned off and the GTO 1B is turned on after a certain short-circuit prevention time.

Here, even if the GTO 1D is turned off, the circuit state does not change because the load current flows from the output terminal X in the direction of the arrow in the drawing through the path 49. Now, when the GTO 1B is turned on, the voltage E of the divided DC power supply 4B is applied to the anode reactor 7B, the current increase rate applied to the GTO 1B is suppressed by the anode reactor 7B, and the load current is supplied by the path 45. start.

Further, the snubber capacitor 5B is discharged to the voltage zero by the path 50. After that, the current flowing in the GTO 1B becomes the load current or more, but the excess current becomes the charging current of the snubber capacitor 5D, and the snubber capacitor 5D is charged.
D is charged to a voltage value that is the sum of the voltage E of the DC power supply 4B and the voltage e of the recovery capacitor 9B.

Immediately after that, the energy is excessively accumulated in the anode reactor 7B, but all the energy is recovered by the capacitor 9B through the path 48. Note that the point different from the conventional FIG. 20 is that the DC power source 4B is connected to this path 48.
It is a point that does not include.

Therefore, the charging voltage of the recovery capacitor 9B can be reduced. Through this process, the load current flows through the path 45, and the circuit operation for changing the output terminal voltage 0 to E by turning off the GTO 1B is completed.

Next, the circuit operation when the output terminal voltage is changed from E to 2E by turning off the GTO 1D will be described. Positive arm GTO1A, negative arm GTO1D
Off, positive arm GTO1B, negative arm GTO1C
Is on, the load current is flowing from the output terminal X in the direction of the arrow in the figure through the path 45, and the snubber capacitor 5
B and 5C have zero voltage, snubber capacitors 5A and 5D
Are charged to the sum of the voltage E of the DC power supplies 4A and 4B and the voltage e of the recovery capacitors 9A and 9B, respectively, and then the GTO1C is turned off, and the GTO1A is turned on after a certain short-circuit prevention time. Consider the case.

Here, even if the GTO 1C is turned off, the circuit state does not change because the load current flows from the output terminal X in the direction of the arrow in the figure by the path 45. Now,
When the GTO 1A is turned on, the voltage E of the divided DC power supply 4A is applied to the anode reactor 7A, and the current increase rate applied to the GTO 1A is changed to the anode reactor 7A.
The load current begins to be supplied by the path 41 while being suppressed by A.

After that, the current flowing into the GTO 1A becomes equal to or larger than the load current, but the excess current is caused by the snubber capacitor 5
The charging current becomes C, and the snubber capacitor 5C is charged to the voltage E of the DC power supply 4A.

Further, the snubber capacitor 5 is connected by the path 51.
A is discharged to a voltage of zero, and the energy stored in the snubber capacitor 5A is recovered by the recovery capacitor 9A via this path 51.

Immediately after that, the energy is excessively stored in the anode reactor 7A, but all the energy is recovered by the recovery capacitor 9A through the path 43. Note that the difference from the conventional FIG. 20 is that this route 43, route 5
1 does not include the DC power supply 4A.

Therefore, the charging voltage of the recovery capacitor 9B can be reduced. Through this process, the load current flows through the path 41, and the circuit operation for changing the output terminal voltage from E to 2E by turning off the GTO 1C is completed.

Next, regarding the switching operation of each GTO 1A, 1B, 1C, 1D when the load current flows in the direction opposite to the arrow in the figure, when the load current flows in the direction of the arrow in the figure Each GTO 1A, 1B, 1C, 1D
Since it is completely symmetrical to the switching operation of, the description thereof will be omitted.

Next, the energy regeneration circuit operation will be described. Although the energy regenerative circuit itself is not the main subject of the present invention, it is shown that the present invention circuit can be implemented using applicable concrete circuits. First, the recovery condenser 9A will be described.

That is, the switch 10A and the diode 1
An energy regeneration circuit is configured by 1A and a reactor 12A. Energy is taken out from a recovery capacitor 9A whose charging polarity is set to be positive in the figure and is regenerated to a divided DC power source 4A to recover the recovery capacitor. It is possible to satisfy the function of the energy regeneration circuit of controlling the charging voltage of 9 A to a constant value e.

The operation of this circuit will be described. First, the switch 10A is turned on to discharge the energy stored in the recovery capacitor 9A to the reactor 12A.

Next, the switch 1 for cutting off the discharge current
When 0A is turned off, the energy stored in the reactor 12A causes a current to flow in the path 52 and is regenerated by the DC power supply 4A. By controlling the on / off period of the switch 10A or its period by the voltage of the recovery capacitor 9A, the charging voltage of the recovery capacitor 9A can be maintained at a constant value.

Since the same applies to the recovery condenser 9B, its explanation is omitted. Further, it is apparent that the same effect can be obtained by applying a known DC-DC current conversion circuit other than the circuit shown in FIG.

Example 2. FIG. 3 shows another embodiment of the present invention corresponding to claim 2, and 1A, 1B, 1C and 1D are
The GTO is a self-extinguishing type semiconductor device. It should be noted that here, only the parts of the above-described embodiment different from those in FIG. 1 will be described.

A series body composed of an auxiliary reactor 17A, a diode 18A and an auxiliary capacitor 19A is connected in parallel to the snubber diode 6B, and the auxiliary capacitor 19A is connected to a recovery capacitor 9A via a diode 20A.

Further, the snubber diode 6C includes an auxiliary reactor 17B, a diode 18B and an auxiliary capacitor 19B.
The series body composed of B is connected in parallel, and the auxiliary capacitor 19
B is connected to the recovery capacitor 9B via the diode 20B.

Next, the operation will be described. The routes shown in the description are collectively shown in FIG. First, GTO1
The circuit operation when the output terminal voltage is changed from 2E to E by turning off A will be described.

The positive arm GTOs 1A and 1B are turned on and the negative arm GTOs 1C and 1D are turned off. A load current flows from the output terminal X in the direction of the arrow in the figure by the path 53, and the snubber capacitors 5A, 5B, Auxiliary capacitor 19
The voltages of A and 19B are zero, the voltage of the snubber capacitor 5C is charged to the voltage E of the DC power supply 4A, and the voltage of the snubber capacitor 5D is the sum of the voltage E of the DC power supply 4B and the voltage of the recovery capacitor 9B. From the charged state, GT
Consider a case where O1A is turned off to interrupt the load current, and GTO1C is turned on after a certain short-circuit prevention time.

When the GTO 1A is turned off, the interrupted load current is bypassed to the path 54, and the snubber capacitor 5A receives the voltage E of the DC power supply 4A and the recovery capacitor 9A.
It is charged to a voltage value that is the sum of the voltage e of A. At this time, the snubber capacitor 5A suppresses the voltage increase rate applied to the GTO 1A.

Immediately after that, the energy is excessively accumulated in the anode reactor 7A, but all the energy is recovered by the recovery capacitor 9A through the path 55. Note that the point different from the conventional FIG. 20 is that the path 55 does not include the DC power supply 4A. Therefore, the recovery capacitor 9A
The charging voltage of can be reduced.

When the GTO 1A is turned off and the GTO 1A is turned on after the short circuit prevention time, the snubber capacitor 5C is discharged to the voltage zero by the path 56. At this time, the rate of increase in current applied to the GTO 1C is determined by the auxiliary reactor 17
It is suppressed by B.

After the snubber capacitor 5C is discharged to a voltage of zero, the energy accumulated in the auxiliary reactor 17B is recovered by the auxiliary capacitor 19B via the path 57. That is, the energy stored in the snubber capacitor 5C is
Once through the auxiliary reactor 17B, the auxiliary capacitor 19
Moved to B.

The auxiliary capacitor 19B has a dotted side as positive, and the snubber capacitor 5C and the auxiliary capacitor 19B.
Is charged to a voltage value V determined by the capacitance ratio of. When the charging voltage of the snubber capacitor 5A becomes equal to or higher than the voltage E, the clamp diode 3A becomes conductive. Through this process, the load current flows through the path 58, and the circuit operation for changing the output terminal voltage from 2E to E by turning off the GTO 1A ends.

Next, the circuit operation when the output terminal voltage is changed from E to 0 by turning off the GTO 1B will be described.

GTO1A of the positive arm is off, GTO1B
Is on, the negative arm GTO1C is on, and the GTO1D is off. A load current is flowing to the output terminal X in the direction of the arrow in the figure by the path 58, and the snubber capacitors 5B, 5
C, the voltage of the auxiliary capacitor 19A is zero, the voltage of the snubber capacitors 5A, 5D is charged to the voltage value of the sum of the voltage E of the DC power supplies 4A, 4B and the voltage e of the recovery capacitors 9A, 9B, and the auxiliary capacitor 19B is charged. Consider a case where the side marked with a dot is positive and the GTO 1B is turned off from a state of being charged to the voltage V to cut off the load current, and the GTO 1D is turned on after a certain short-circuit prevention time.

When the GTO 1B is turned off, the interrupted load current is bypassed to the path 59 and the snubber capacitor 5B is charged to the voltage E of the DC power supply 3B. At this time, the snubber capacitor 5B suppresses the voltage increase rate applied to the GTO 1B.

When the GTO1B is turned off and the GTO1D is turned on after the short circuit prevention time, the snubber capacitor 5D is discharged to the voltage V by the path 60, and from the voltage V, the snubber capacitor 5D is the path 60 and the auxiliary capacitor 19B is the path 61. At the same time, discharges to zero voltage.

Therefore, the energy accumulated in the snubber capacitor 5D and the auxiliary capacitor 19B is recovered in the recovery capacitor 9B by this operation. Immediately after that, energy is excessively stored in the anode reactor 7B, but all the energy is recovered by the recovery capacitor 9B through the path 62.

Note that the point different from the conventional FIG. 20 is that the path 60, the path 61, and the path 62 do not include the DC power supply 4B. Therefore, the charging voltage of the recovery capacitor 9B can be reduced.

When the charging voltage of the snubber capacitor 5B reaches the voltage E, the freewheel diodes 2C and 2D are turned on. Through this process, the load current flows through the path 63, and the circuit operation when changing the output terminal voltage from E to 0 by turning off the GTO 1B is completed.

Next, the circuit operation when the output terminal voltage is changed from 0 to E by turning off the GTO 1D will be described.

The positive arm GTOs 1A and 1B are off, the negative arm GTOs 1C and 1D are on, and the load current flows from the output terminal X in the direction of the arrow in the figure by the path 63, so that the snubber capacitors 5C and 5D, Auxiliary capacitor 19
The voltages of A and 19B are zero, the snubber capacitor 5A is charged to the voltage value of the sum of the voltage E of the DC power supply 4A and the voltage e of the recovery capacitor 9A, and the snubber capacitor 5B is charged to the voltage E of the DC power supply 4B. From the state, turn off DTO1D, and after a certain short-circuit prevention time, GTO1B
Consider the case of turning on.

Here, even if the GTO 1D is turned off, the circuit state does not change because the load current flows from the output terminal X in the direction of the arrow in the figure by the path 63. Well GT
When O1B is turned on, the anode reactor 7B
The divided voltage E of the DC power supply 4B is applied to the GT
The load current starts to be supplied through the path 58 while the current increase rate applied to O1B is suppressed by the anode reactor 7B.

Further, the snubber capacitor 5B is discharged to zero voltage by the path 64. At this time, the current increase rate applied to the GTO 1B is suppressed by the auxiliary reactor 17A. After the snubber capacitor 5B is discharged to zero voltage, the energy stored in the auxiliary reactor 17A is recovered to the auxiliary capacitor 19A by the path 65.

That is, the energy stored in the snubber capacitor 5B is once transferred to the auxiliary capacitor 19A via the auxiliary reactor 17A. Auxiliary capacitor 19A
Is charged to a voltage value V determined by the electrostatic capacitances of the snubber capacitor 5B and the auxiliary capacitor 19A, with the dotted side as positive.

The current flowing through the GTO 1B becomes equal to or larger than the load current, but the excess current is caused by the snubber capacitor 5D.
Charging current, and is charged to a voltage value of the sum of the voltage E of the DC power supply 4B and the recovery capacitor 9B.

Immediately after that, energy is excessively stored in the anode reactor 7B, but all the energy is recovered by the recovery capacitor 9B through the path 62.

Note that the point different from the conventional FIG. 20 is that the path 62 does not include the DC power supply 4B. Therefore, the charging voltage of the recovery capacitor 9B can be reduced.
Through this process, the load current flows through the path 58, and the output terminal voltage is reduced to 0 by turning off the GTO 1B.
The circuit operation when changing from E to E ends.

Next, the circuit operation when the output terminal voltage is changed from E to 2E by turning off the GTO 1C will be described.

Positive arm GTO 1A, negative arm GTO
1D off, positive arm GTO 1B, negative arm GTO
1C is on, a load current is flowing from the output terminal X in the direction of the arrow in the figure through the path 58, and the voltages of the snubber capacitors 5B and 5C and the auxiliary capacitor 19B are zero,
The voltage of the snubber capacitors 5A and 5D is the DC power source 4 respectively.
Voltage E of A and 4B and voltage e of recovery capacitors 9A and 9B
The auxiliary capacitor 19A is charged to the voltage value of the sum of
Consider a case where O1C is turned off and GTO1A is turned on after a certain short-circuit prevention time.

Here, even if the GTO 1C is turned off, the recovery state does not change because the load current flows from the output terminal X in the direction of the arrow in the figure by the path 58.

Now, when GTO1A is turned on,
A divided voltage E of the DC power supply 4A is applied to the anode reactor 7A, and the current increase rate applied to the GTO 1A is suppressed by the anode reactor 7A, while the load current starts to be supplied through the path 53.

After that, the current flowing in the GTO 1A becomes the load current or more, but the excess current becomes the charging current of the snubber capacitor 5C, and the snubber capacitor 5C is charged to the voltage E of the DC power supply 4A.

Further, the snubber capacitor 5 is connected by the route 66.
A discharges to the voltage V, and from the voltage V, the snubber capacitor 5A is on the path 66 and the auxiliary capacitor 19A is on the path 6.
At the same time, it discharges to zero voltage at 7.

Therefore, the energy stored in the snubber capacitor 5A and the auxiliary capacitor 19A is recovered by the recovery capacitor 9A by this operation. Immediately after that, the energy is excessively stored in the anode reactor 7A, but all the energy is recovered by the recovery capacitor 9A by the path 55.

Note that the point different from the conventional FIG. 20 is that the DC power supply 4A is not included in the paths 55, 66, and 67. Therefore, the charging voltage of the recovery capacitor 9A can be reduced. Through this process, the load current flows through the path 1, and the circuit operation when the output terminal voltage is changed from E to 2E by turning off the GTO 1C is completed.

Next, regarding the switching operation of each GTO 1A, 1B, 1C, 1D when the load current flows in the direction opposite to the arrow in the figure, when the load current flows in the direction of the arrow in the figure Each GTO 1A, 1B, 1C, 1D
Since it is completely symmetrical to the switching operation of, the description thereof will be omitted.

A first energy regeneration circuit E1 composed of a switch 10A connected to the recovery capacitor 9A, a diode 11A and a reactor 12A, and a switch 10B connected to the recovery capacitor 9B, a diode 11B and a reactor 12B. The operation of the second energy regeneration circuit E2 is exactly the same as that shown in FIG.

Example 3. FIG. 5 shows still another embodiment of the three-level inverter device of the present invention corresponding to claim 2, and 1A, 1B, 1C and 1D are GTOs as self-extinguishing type semiconductor devices.

Note that only parts different from those in FIG. 3 will be described here.

That is, the recovery capacitors 9A and 9B are located at the same positions as in the conventional FIG. In this configuration, the charging voltage of the recovery capacitors 9A and 9B is the DC power source 4
The voltage E is equal to or higher than the voltages E of A and 4B. Therefore, the three-level inverter device of FIG. 3 is advantageous in practical use.

Example 4. FIG. 6 shows still another embodiment of the three-level inverter device of the present invention corresponding to claim 3, and 1A, 1B, 1C and 1D are GTOs as self-arc-extinguishing type semiconductor devices. Note that only parts different from those in FIG. 1 will be described here.

That is, the connection point between the snubber diode 6B and the snubber capacitor 5B is connected to the intermediate potential point O via the auxiliary switch 21A (here, GTO is applied), the auxiliary reactor 22, the diode 23A and the recovery capacitor 9D. The connection point between the snubber diode 6C and the snubber capacitor 5C is connected to the intermediate potential O via the auxiliary switch 21B, the auxiliary reactor 22, the diode 23B, and the recovery capacitor 9C.

In addition, the third connecting to the recovery condenser 9C
The energy regenerating circuit E3 is composed of the switch 10C, the diode 11C, and the reactor 12C, and the fourth energy regenerating circuit E4 connected to the recovery capacitor 9D is composed of the switch 10D, the diode 11D, and the reactor 12D.

Next, the operation will be described with reference to FIG. The routes shown in the description are collectively shown in FIG. 7.
Since the difference from the operation of FIG. 1 is the operation of recovering the energy accumulated in the snubber capacitors 5B and 5C to the recovery capacitors 9D and 9C, respectively, the description of the operation is limited here.

First, the circuit operation when the energy stored in the snubber capacitor 5B by the turn-on of the GTO 1B is recovered by the recovery capacitor 9D will be described. From the state where the snubber capacitor 5B is charged to the sum of the voltage E of the DC power source 4B and the charging voltage e of the recovery capacitor 9D,
At the same time that TO1B is turned on, GTO21A is turned on.

Then, the discharge path of the snubber capacitor 5B is constructed as the path 68 via the recovery capacitor 9D. At this time, the current increase rate applied to the GTOs 1B and 21A is suppressed by the auxiliary reactor 22.

After that, even if the snubber capacitor 5B is discharged to a zero voltage, energy is accumulated in the auxiliary reactor 22, but the energy is recovered by the recovery capacitor 9D through the path 69. The timing for turning off the GTO 21A is as follows.
Synchronize with the timing to turn off TO1C.

Next, the circuit operation when the energy stored in the snubber capacitor 5C is recovered by the recovery capacitor 9C when the GTO 1C is turned on will be described. From the state where the snubber capacitor 5C is charged to the sum of the voltage E of the DC power supply 4A and the charging voltage e of the recovery capacitor 9C,
At the same time that TO1C is turned on, GTO21B is turned on.

Then, the discharge path of the snubber capacitor 5C is constructed as the path 70 via the recovery capacitor 9C. At this time, the current increase rate applied to the GTOs 1C and 21B is suppressed by the auxiliary reactor 22.

After that, even if the snubber capacitor 5C is discharged to a zero voltage, energy is accumulated in the auxiliary reactor 22, but the energy is recovered by the recovery capacitor 9C through the path 71. The timing for turning off the GTO 21B is as follows.
Synchronize with the timing of turning off TO1B.

Also, a switch 10C, a diode 11C, and a reactor 12C which are connected to the recovery capacitor 9C.
An energy regeneration circuit E3 composed of a switch 10D and a diode 1 connected to a recovery capacitor 9D.
The operation of the energy regeneration circuit E4 including the 1D and the reactor 12D is exactly the same as that shown in FIG.

Note that the GTOs 21A and 21B need a snubber circuit for practical use. A known snubber circuit including a snubber capacitor, a snubber diode, and a discharge resistor may be applied to the snubber circuit, but if a highly efficient circuit is required, the GTO 21A and 21B are connected in parallel as shown in FIG. The energy stored in the snubber capacitors 24A and 24B thus collected can be recovered in the recovery capacitors 9C and 9D.

Example 5. FIG. 9 shows still another embodiment of the present invention, which corresponds to claim 4, 1A, 1B, 1C, 1
D is a GTO as a self-arc-extinguishing type semiconductor device. It should be noted that here, only the parts different from those in FIG. 1 will be described.

First, the connection point between the snubber diode 6B and the snubber capacitor 5B is the auxiliary switch 21A (here, G).
(TO is applied), auxiliary reactor 22, diode 2
3A, the recovery capacitor 9D is connected to the intermediate potential point O, and the snubber diode 6C and the snubber capacitor 5 are connected.
Connection point of C is auxiliary switch 21B, auxiliary reactor 2
2, it is connected to the intermediate potential point O via the diode 23B and the recovery capacitor 9C.

Further, the energy regeneration circuit E3 connected to the recovery capacitor 9C is connected to the switch 10C and the diode 11
C, reactor 12C, recovery condenser 9
The energy regeneration circuit E4 connected to D is connected to the switch 10D,
It is composed of a diode 11D and a reactor 12D.

Next, the operation will be described. The routes shown in the description are collectively shown in FIG. The operation of FIG. 9 differs from that of FIG. 1 in that the snubber capacitor 5B,
The energy stored in 5C is recovered by a condenser 9D,
Since this is an operation for collecting the data in 9C, the description is limited to that operation here.

First, the circuit operation when the energy stored in the snubber capacitor 5B by the turn-on of the GTO 1B is recovered by the recovery capacitor 9D will be described. From the state where the snubber capacitor 5B is charged to the sum of the voltage E of the DC power source 4B and the charging voltage e of the recovery capacitor 9D,
At the same time that TO1B is turned on, GTO21A is turned on.

Then, the discharge path of the snubber capacitor 5B is constructed as the path 73 through the recovery capacitor 9D. At this time, the current increase rate applied to the GTOs 1B and 21A is suppressed by the auxiliary reactor 22.

After that, even if the snubber capacitor 5B is discharged to a zero voltage, energy is accumulated in the auxiliary reactor 22, but the energy is recovered by the recovery capacitor 9D through the path 73. The timing for turning off the GTO 21A is the same as turning off the GTO 1B or GT.
Synchronize with the timing of turning off O1C.

Next, the circuit operation when the energy stored in the snubber capacitor 5C is recovered by the recovery capacitor 9C when the GTO 1C is turned on will be described. From the state where the snubber capacitor 5C is charged to the sum of the voltage E of the DC power supply 4A and the charging voltage e of the recovery capacitor 9C,
At the same time that TO1C is turned on, GTO21B is turned on.

Then, the discharge path of the snubber capacitor 5C is constructed as the path 74 via the recovery capacitor 9C. At this time, the current increase rate applied to the GTOs 1C and 21B is suppressed by the auxiliary reactor 22.

After that, even if the snubber capacitor 5C is discharged to a zero voltage, energy is accumulated in the auxiliary reactor 22, but the energy is recovered by the recovery capacitor 9C through the path 75. The timing for turning off the GTO 21B is as follows.
Synchronize with the timing of turning off TO1B.

A third energy regeneration circuit E3 composed of a switch 10C connected to the recovery capacitor 9C, a diode 11C, and a reactor 12C, and a switch 10D connected to the recovery capacitor 9D, a diode 11D, and a reactor 12D. The operation of the fourth energy regeneration circuit E4 performed is the same as that shown in FIG.

The GTOs 21A and 21B require snubber circuits. Snubber capacitor in the snubber circuit,
A known snubber circuit composed of a snubber diode and a discharge resistor may be applied, but if a circuit with higher efficiency is required, the snubber capacitors 24A and 24B connected to the GTOs 21A and 21B are stored in the snubber capacitors 24A and 24B as shown in FIG. It is also possible to recover the generated energy in the recovery capacitors 9C and 9D.

Example 6. 12, 13, 14 and 15 show another embodiment of the present invention corresponding to claim 5, and 1A, 1B, 1C and 1D are GTOs as self-extinguishing type semiconductor devices.

First, in FIGS. 12 and 13, when the three-level inverter device of FIGS. 1 and 3 has a multi-phase inverter configuration, the recovery capacitors 9A and 9B and the energy regenerating circuits E1 and E2 connected thereto are provided in plural. They are commonly connected for phases. Since the basic operation of the circuit is exactly the same as that described in detail in the first and second embodiments, it is omitted here.

Next, FIGS. 14 and 15 show the recovery capacitors 9A, 9B, 9C, 9D and the energy regeneration circuit E1 connected thereto when the three-level inverter device of FIGS. 6 and 9 has a multi-phase inverter configuration. , E2, E3, E
4 is commonly connected for a plurality of phases. Since the basic operation of the circuit is exactly the same as that described in detail in the fourth and fifth embodiments, it is omitted here.

Example 7. FIG. 16 shows another embodiment of the present invention corresponding to claim 6, which is 1A, 1B, 1C, 1
D is a GTO as a self-arc-extinguishing type semiconductor device. It should be noted that here, only the parts different from those in FIG. 1 will be described.

First, the connection point between the snubber capacitor 5B and the snubber diode 6B and the output terminal X are connected via the primary side of the transformer 26A, the auxiliary switch 27A (here, GTO is applied) and the auxiliary reactor 28, and the transformation is performed. The secondary side of the device 26A is connected to a diode rectifying bridge circuit 29A as a rectifying circuit provided in the DC power supply 4A.

The connection point between the snubber capacitor 5C and the snubber diode 6C and the output terminal X are connected to the primary side of the transformer 26B, the auxiliary switch 27B and the auxiliary reactor 28.
And the secondary side of the transformer 26B is connected to the DC power source 4
It is connected to a diode rectifying bridge circuit 29B as a rectifying circuit provided in B.

The diode rectifying bridge circuit 29
Since A and 29B are insulated from the primary side and the secondary side of the transformers 26A and 26B, they may be connected to either of the DC power supplies 4A and 4B.

Next, the operation will be described. The routes shown in the description are collectively shown in FIG. The operation of FIG. 16 differs from that of FIG. 1 in that the snubber capacitor 5
The energy stored in B and 5C is transferred to transformers 26A and 2A, respectively.
Since the operation is regenerative to the DC power supplies 4A and 4B by 6B, the description of the operation is limited here.

First, the energy stored in the snubber capacitor 5B when the GTO 1B is turned on is supplied to the DC power source 4B.
The circuit operation when regenerative is performed will be described. While the snubber capacitor 5B is charged to the voltage E of the DC power supply 4B, the GTO1B is turned on and at the same time the GTO2 is turned on.
Turn on 7A.

Then, the discharge path of the snubber capacitor 5B is configured as the path 76 passing through the primary side of the transformer 26A. At this time, the current increase rate applied to the GTOs 1B and 27A is suppressed by the auxiliary reactor 28.

After that, even if the snubber capacitor 5B is discharged to the zero voltage, energy is accumulated in the auxiliary reactor 28, but the energy continues to flow through the primary side of the transformer 26B by the path 77.

Assuming that the turns ratio of the primary side and the secondary side of the transformer 26A is 1: n, the dotted side is positive while the current is flowing to the primary side of the transformer 26A. A voltage is generated. Further, the voltage E of the DC power supply 4A is applied to the secondary side of the transformer 26A with the dotted side being positive.

Further, a current of 1 / n of the current on the primary side flows through the secondary side of the transformer 26A and is regenerated by the DC power source 4B. If the current flowing through the auxiliary reactor 28 becomes zero,
A reverse polarity overvoltage is momentarily generated on the secondary side of the transformer 26A, and current continues to flow on the path 77 on the primary side.
The voltage drop of 7 resets the transformer 26A.

At this time, when the GTO 27A is turned off, the primary side of the transformer 26A is opened, and the exciting current flowing through the secondary side is regenerated by the DC power supply 4A. Therefore, on the secondary side of the transformer 26A, the DC power source 4A has a polarity opposite to that at the time of regeneration
The voltage E is applied to reset at high speed.

In this operation, the secondary side of the transformer 26A is clamped to the voltage E of the DC power supply 4A. The reset ends when the exciting current of the transformer 26A becomes zero.

Next, the energy stored in the snubber capacitor 5C when the GTO 1C is turned on is transferred to the transformer 26B.
Regarding the circuit operation when regenerating to the DC power supply 4B by using the, the operation and the principle when regenerating the energy stored in the snubber capacitor 5B by the turn-on of the GTO 1B to the DC power supply 4A using the transformer 26A Are exactly the same, so the description is omitted.

Note that the GTOs 27A and 27B practically require snubber circuits. A known snubber circuit including a snubber capacitor, a snubber diode, and a discharge resistor may be applied to the snubber circuit, but the snubber capacitor may have a very small capacitance because the breaking current is about the exciting current.

Example 8. FIG. 18 shows still another embodiment of the present invention corresponding to claim 5, 1A, 1B, 1C,
1D is a GTO as a self-arc-extinguishing type semiconductor device. It should be noted that here, only the parts of the first embodiment different from those of FIG. 1 will be described.

The connection point of the snubber capacitor 5B and the snubber diode 6B and the intermediate potential point O are connected via the primary side auxiliary switch 27A of the transformer 26A (here, GTO is applied) and the auxiliary reactor 28, and the transformer is connected. The secondary side of 26A is connected to the diode rectifying bridge circuit 29A provided in the DC power supply 4A.

The connection point of the snubber capacitor 5C and the snubber diode 6C and the intermediate potential point O are the primary side of the transformer 26B, the auxiliary switch 27B and the auxiliary reactor 28.
And the secondary side of the transformer 26B is connected to the DC power source 4
B is connected to the diode rectifying bridge 29B.

Next, the operation will be described. The routes shown in the description are collectively shown in FIG. The difference between the operation of FIG. 18 and the operation of FIG. 15 is that the snubber capacitor 5
Since it is the discharge path of B and 5C, the description is limited to that path here.

First, the energy stored in the snubber capacitor 5B when the GTO 1B is turned on is supplied to the DC power source 4A.
The case of regenerating into is explained. Snubber capacitor 5
From the state where B is charged to the voltage E of the DC power supply 4B,
At the same time as turning on GTO1B, GTO27A
Turn on. Then, the discharge path of the snubber capacitor 5B is configured as the path 78 passing through the primary side of the transformer 26A.

Next, the energy stored in the snubber capacitor 5C when the GTO 1C is turned on is supplied to the DC power source 4B.
The case of regenerating into is explained. Snubber capacitor 5
From the state where C is charged to the voltage E of the DC power supply 4A,
At the same time as turning on GTO1C, GTO27B
Turn on. Then, the discharge path of the snubber capacitor 5C is configured as the path 79 passing through the primary side of the transformer 26B.

The operation of regenerating the energy stored in the snubber capacitors 5B and 5C to the DC power source 4B using the transformers 26A and 26B is completely the same in principle as that of the seventh embodiment. Is omitted.

[0153]

As described above, according to the first aspect of the present invention, the reactor connected in series to the self-arc-extinguishing type semiconductor element forming each of the positive and negative arms and the parallel connection to the self-extinguishing type semiconductor element. Snubber circuit and a snubber capacitor that are connected in parallel to the second and third self-arc-extinguishing type semiconductor elements to form the one snubber circuit. A discharge resistor connected between the connection points and a first connection connecting the connection point of the snubber diode and the snubber capacitor, which are connected in parallel to the first self-arc-extinguishing type semiconductor element to form the snubber circuit, and the positive side bus bar. Snubber diode and snubber capacitor, which are connected in parallel to the diode, the first recovery capacitor, and the fourth self-arc-extinguishing semiconductor element to form the snubber circuit. A second diode and a second recovery capacitor that connect the connection point to the negative side bus and the first energy regeneration circuit to extract energy from the first recovery capacitor to obtain the intermediate potential. The positive side of the DC power supply divided by the points, and the second energy regeneration circuit causes the energy to be extracted from the second recovery capacitor, and the negative side of the DC power supply divided by the intermediate potential point. Since the regeneration capacitor is configured to be regenerated, the withstand voltage of the recovery capacitor for recovering the energy accumulated in the snubber capacitor and the anode reactor can be reduced, and thus the recovery capacitor can be downsized.

According to the second aspect of the present invention, the reactor connected in series to the self-arc-extinguishing type semiconductor element forming each of the positive and negative arms, the snubber diode and the snubber capacitor connected in parallel to each of the self-extinguishing type semiconductor elements. And a snubber circuit connected in parallel to the first self-arc-extinguishing semiconductor element to form the snubber circuit, and a first diode connecting the connection point of the snubber capacitor and the positive side bus line. And a first recovery capacitor and a fourth
A second diode and a second recovery capacitor which are connected in parallel to the self-extinguishing type semiconductor element of the snubber circuit and form a connection point between the snubber diode and the snubber capacitor and the negative side bus, and a second self A first series body composed of a capacitor, a diode, and an auxiliary reactor connected in parallel to the arc-quenching semiconductor element and connected in parallel to a snubber diode that forms the snubber circuit; and a capacitor that forms the first series body. A diode connected to the first recovery capacitor, a capacitor connected in parallel to the third self-arc-extinguishing semiconductor element and connected in parallel to a snubber diode forming the snubber circuit, a diode, and an auxiliary reactor; 2 series body and the capacitor forming the second series body are connected to the second recovery capacitor. And a second energy regeneration circuit that causes the first energy regeneration circuit to extract energy from the first recovery capacitor and regenerate it to the positive side of the DC power supply divided at the intermediate potential point. Causing the circuit to extract energy from the second recovery capacitor,
Since it is configured to regenerate on the negative side of the DC power supply that is divided at the intermediate potential point, in addition to the above effect that the withstand voltage of the recovery capacitor can be reduced, the energy consumed by the conventional discharge resistor is recovered. There is an effect that a DC power source can be regenerated and a highly efficient operation of the device can be realized.

According to the invention of claim 3, the first and second
The recovery capacitor and the first and second energy regeneration circuits respectively connected to the first and second recovery capacitors are configured to be commonly connected for a plurality of phases. Therefore, the recovery capacitor and the energy regeneration circuit There is an effect that the circuit can be shared by a plurality of phases, and the structure of the inverter device can be simplified, the cost can be reduced, and the size can be reduced.

According to the fourth aspect of the present invention, the reactor is connected in series to the self-arc-extinguishing type semiconductor elements forming the positive and negative arms, and the snubber diode and the snubber capacitor are connected in parallel to the self-extinguishing type semiconductor elements. And a snubber circuit connected to the first self-arc-extinguishing semiconductor element to form the snubber circuit, and a first diode connecting a connection point of the snubber capacitor and a positive side bus bar. And a first recovery capacitor and a fourth
A second diode and a second recovery capacitor that connect the connection point of the snubber diode and the snubber capacitor, which are connected in parallel to the self-extinguishing type semiconductor element of FIG. An auxiliary switch, a reactor, a diode and a third recovery element connected in series, which are connected in parallel to the arc-extinguishing semiconductor element and connect the connection point of the snubber diode and the snubber capacitor forming the snubber circuit to the intermediate potential point. A capacitor, a third self-arc-extinguishing type semiconductor element, which is connected in parallel to form a snubber circuit to form a snubber diode and a snubber capacitor. The energy recovery circuit includes a diode and a fourth recovery capacitor, and the energy recovery circuit includes the first to fourth recovery circuits. Since energy is taken out from each of the capacitors and regenerated to the positive side or negative side of the DC power supply divided at the intermediate potential point, the snubber capacitor and the anode reactor are connected by the recovery capacitor connected to the intermediate potential point. There is an effect that the energy that is accumulated in all of the above can be recovered.

According to the invention of claim 5, the first, second, third and fourth recovery capacitors and the first, second and third recovery capacitors are provided.
Since the first, second, third and fourth energy regeneration circuits respectively connected to the first and fourth recovery capacitors are configured to be commonly connected for a plurality of phases, each recovery capacitor and energy recovery circuit Is shared by a plurality of phases, and there is an effect that the configuration of the inverter device can be simplified and the cost can be reduced.

According to the sixth aspect of the present invention, the reactor connected in series to the self-arc-extinguishing type semiconductor element forming each of the positive and negative arms, the snubber diode and the snubber capacitor connected in parallel to the self-extinguishing type semiconductor element. A snubber circuit formed by connecting in series with a first self-arc-extinguishing type semiconductor element, and a snubber diode and a snubber capacitor that form the above-mentioned snubber circuit, and a positive side bus line.
Diode and the first recovery capacitor, and a second diode that is connected in parallel to the fourth self-arc-extinguishing semiconductor element to form the snubber circuit and that connects the connection point of the snubber capacitor and the negative side bus bar. And a second recovery capacitor, an energy recovery circuit for extracting energy from each of the first and second recovery capacitors, and regenerating to the positive side and the negative side of the DC power supply divided at the intermediate potential point, and the second recovery capacitor. , The third self-extinguishing type semiconductor element is connected in parallel, and the connection point of the snubber capacitor and the snubber diode, which constitutes the snubber circuit, and the output terminal or the intermediate potential point are individually provided through a common reactor. A primary side of the transformer to be connected or an auxiliary switch is provided, and the rectifier circuit is connected to the intermediate potential point or the intermediate potential point on the secondary side of each transformer. Since it is configured to be connected between the positive side and the negative side of the above DC power source, the reset time of the transformer can be shortened, the frequency of the device can be increased, and the breakdown voltage of the components can be changed between the PN of the DC power source. It is possible to obtain a voltage that can be reduced from the voltage of.

Then, the 3-level inverter device
Applying to level converter device, 3 level converter
When driving an induction motor as an inverter system,
There is an effect that the running cost is reduced and the energy saving of the entire system can be realized.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a three-level inverter device according to an embodiment of the present invention.

FIG. 2 is a current path chart showing a current path for explaining the operation of FIG.

FIG. 3 is a circuit diagram showing another embodiment of the three-level inverter device of the present invention.

FIG. 4 is a current path chart showing a current path for explaining the operation of FIG.

FIG. 5 is a circuit diagram showing still another embodiment of the three-level inverter device of the present invention.

FIG. 6 is a circuit diagram showing another embodiment of a three-level inverter device according to the present invention.

7 is a current path chart showing a current path for explaining the operation of FIG.

FIG. 8 is a circuit diagram showing another embodiment of the three-level inverter device according to the present invention.

FIG. 9 is a circuit diagram showing another embodiment of a three-level inverter device according to the present invention.

10 is a current path chart showing a current path for explaining the operation of FIG.

FIG. 11 is a circuit diagram showing still another embodiment of the three-level inverter device according to the present invention.

FIG. 12 is a circuit diagram showing another embodiment of the three-level inverter device according to the present invention.

FIG. 13 is a circuit diagram showing still another embodiment of the three-level inverter device according to the present invention.

FIG. 14 is a circuit diagram showing still another embodiment of the three-level inverter device according to the present invention.

FIG. 15 is a circuit diagram showing another embodiment of the three-level in butter device according to the present invention.

FIG. 16 is a circuit diagram showing another embodiment of the three-level inverter device according to the present invention.

FIG. 17 is a current path chart showing a current path for explaining the operation of FIG.

FIG. 18 is a circuit diagram showing still another embodiment of the three-level inverter device according to the present invention.

FIG. 19 is a current path chart showing a current path for explaining the operation of FIG.

FIG. 20 is a circuit diagram showing a conventional three-level inverter device.

FIG. 21 is a circuit diagram showing another conventional three-level inverter device.

[Explanation of symbols]

1A, 1B, 1C, 1D GTO (self-extinguishing type semiconductor device) 2A, 2B, 2C, 2D Freewheel diode 3A, 3B Clamp diode 4A, 4B DC power supply 5A, 5B, 5C, 5D Snubber capacitor 6A, 6B, 6C , 6D Snubber diode 7A, 7B Anode reactor 8A Diode (first diode) 8B Diode (second diode) 9A, 9B, 9C, 9D Recovery capacitor 10A, 10B, 10C, 10D switch 11A, 11B, diode 12A, 12B , 12C, 12D Reactor 13 Discharge resistance 17A, 17B Auxiliary reactor 18A, 18B Diode 19A, 19B Capacitor 20A, 20B Diode 21A, 21B Switch 22 Reactor 23A, 23B Diode 26A, 2 B Transformer 27A, 27B Auxiliary switch 29A, 29B Diode rectifier bridge circuit (rectifier circuit) O Intermediate potential point X Output terminal E1 First energy regeneration circuit E2 Second energy regeneration circuit E3 Third energy regeneration circuit E4 Fourth Energy regeneration circuit

Claims (6)

[Claims] 1. A plurality of self-extinguishing semiconductor elements connected in series as positive and negative arms between positive and negative busbars of a DC power supply having an intermediate potential point, and connected in antiparallel to each of the self-extinguishing semiconductor elements. A free wheel diode, a first clamp diode connecting a series connection point of the first and second self-arc-extinguishing semiconductor elements forming the positive arm and the intermediate potential point, and a first clamp diode forming the negative arm. A third clamp diode for connecting a series connection point of the third and fourth self-arc-extinguishing semiconductor elements and the intermediate potential point, and an output terminal connected to a connection point of the positive arm and the negative arm. In a three-level inverter device, a reactor connected in series to the self-extinguishing type semiconductor elements forming the positive and negative arms and a snubber die connected in parallel to the self-extinguishing type semiconductor elements. A snubber circuit formed by connecting an ode and a snubber capacitor in series, and each connection point of a snubber diode and a snubber capacitor that are connected in parallel to the second and third self-arc-extinguishing type semiconductor elements to form the snubber circuit. A discharge resistor connected between the first self-arc-extinguishing semiconductor element and a first snubber diode connected in parallel to the first self-extinguishing semiconductor element to form a snubber circuit; A diode and a first recovery capacitor are connected in parallel to the fourth self-arc-extinguishing semiconductor element to form the snubber circuit, and a second connection point is formed between the connection point of the snubber diode and the snubber capacitor and the negative bus. The energy is extracted from the diode and the second recovery capacitor, and the first recovery capacitor, and is divided at the intermediate potential point. A first energy regenerative circuit that regenerates to the positive side of the current source and a second energy regenerative circuit that takes out energy from the second recovery capacitor and regenerates to the negative side of the DC power source divided at the intermediate potential point. A three-level inverter device characterized by being provided with. 2. A plurality of self-extinguishing semiconductor elements connected in series as positive and negative arms between positive and negative busbars of a DC power supply having an intermediate potential point, and connected in antiparallel to each of the self-extinguishing semiconductor elements. A free wheel diode, a first clamp diode connecting a series connection point of the first and second self-arc-extinguishing semiconductor elements forming the positive arm and the intermediate potential point, and a first clamp diode forming the negative arm. A third clamp diode for connecting a series connection point of the third and fourth self-arc-extinguishing semiconductor elements and the intermediate potential point, and an output terminal connected to a connection point of the positive arm and the negative arm. In a three-level inverter device, a reactor connected in series to the self-extinguishing type semiconductor elements forming the positive and negative arms and a snubber die connected in parallel to the self-extinguishing type semiconductor elements. A snubber circuit in which an ode and a snubber capacitor are connected in series, a connection point of the snubber diode and the snubber capacitor which are connected in parallel to the first self-arc-extinguishing type semiconductor element to form the snubber circuit, and the positive side busbar are connected. The first diode and the first recovery capacitor to be connected, and the connection point of the snubber diode and the snubber capacitor, which are connected in parallel to the fourth self-arc-extinguishing semiconductor element to form the snubber circuit, and the negative side busbar are connected. A second diode and a second recovery capacitor to connect,
A first series body composed of a capacitor, a diode, and an auxiliary reactor that are connected in parallel to the second self-arc-extinguishing semiconductor element and are connected in parallel to a snubber diode that forms the snubber circuit, and the first series body. And a diode for connecting a capacitor forming a capacitor to the first recovery capacitor and a capacitor connected in parallel to the third self-arc-extinguishing type semiconductor element and a snubber diode forming the snubber circuit. A second series body composed of an auxiliary reactor, a diode connecting a capacitor forming the second series body to the second recovery capacitor, and energy taken out from the first recovery capacitor at the intermediate potential point The first energy regeneration circuit that is regenerated to the positive side of the DC power supply that is divided, and the second recovery capacitor Removed conservation, three-level inverter device is characterized by providing a second energy recovery circuit for regenerating the negative side of the DC power source divided by the intermediate potential point. 3. The first and second recovery capacitors and the first and second energy regeneration circuits respectively connected to the first and second recovery capacitors are connected in common for a plurality of phases. The three-level inverter device according to claim 1 or 2, characterized in that. 4. A plurality of self-extinguishing semiconductor elements connected in series as positive and negative arms between positive and negative busbars of a DC power supply having an intermediate potential point, and connected in antiparallel to each of the self-extinguishing semiconductor elements. A free wheel diode, a first clamp diode connecting a series connection point of the first and second self-arc-extinguishing semiconductor elements forming the positive arm and the intermediate potential point, and a first clamp diode forming the negative arm. A third clamp diode for connecting a series connection point of the third and fourth self-arc-extinguishing semiconductor elements and the intermediate potential point, and an output terminal connected to a connection point of the positive arm and the negative arm. In a three-level inverter device, a reactor connected in series to the self-extinguishing type semiconductor elements forming the positive and negative arms and a snubber die connected in parallel to the self-extinguishing type semiconductor elements. A snubber circuit in which an ode and a snubber capacitor are connected in series, a connection point of the snubber diode and the snubber capacitor which are connected in parallel to the first self-arc-extinguishing type semiconductor element and constitute the snubber circuit, and the positive side busbar are connected. The first diode and the first recovery capacitor to be connected, and the connection point of the snubber diode and the snubber capacitor, which are connected in parallel to the fourth self-arc-extinguishing semiconductor element to form the snubber circuit, and the negative side busbar are connected. A second diode and a second recovery capacitor to connect,
Auxiliary switch, reactor and diode connected in series, which are connected in parallel to the second self-extinguishing semiconductor element and connect the connection point of the snubber diode and the snubber capacitor forming the snubber circuit to the intermediate potential point. And a third recovery capacitor and a snubber diode and a snubber capacitor which are connected in parallel to the third self-arc-extinguishing semiconductor element and constitute the snubber circuit, and the connection point of the snubber capacitor is connected in series to the intermediate potential point. Auxiliary switch, reactor, diode and fourth recovery capacitor,
An energy regenerating circuit for retrieving energy from each of the first to fourth recovery capacitors and regenerating to the positive or negative side of the DC power supply divided at the intermediate potential point is provided. Inverter device. 5. The first, second, third and fourth recovery capacitors and first, second, third and fourth recovery capacitors respectively connected to the first, second, third and fourth recovery capacitors. Fourth
5. The three-level inverter device according to claim 4, wherein the energy regenerating circuit of 1. is connected in common for a plurality of phases. 6. A plurality of self-extinguishing semiconductor elements connected in series as positive and negative arms between positive and negative busbars of a DC power supply having an intermediate potential point, and connected in antiparallel to each of the self-extinguishing semiconductor elements. A free wheel diode, a first clamp diode connecting a series connection point of the first and second self-arc-extinguishing semiconductor elements forming the positive arm and the intermediate potential point, and a first clamp diode forming the negative arm. A third clamp diode for connecting a series connection point of the third and fourth self-arc-extinguishing semiconductor elements and the intermediate potential point, and an output terminal connected to a connection point of the positive arm and the negative arm. In a three-level inverter device, a reactor connected in series to the self-extinguishing type semiconductor elements forming the positive and negative arms and a snubber die connected in parallel to the self-extinguishing type semiconductor elements. A snubber circuit in which an ode and a snubber capacitor are connected in series, a connection point of the snubber diode and the snubber capacitor which are connected in parallel to the first self-arc-extinguishing type semiconductor element to form the snubber circuit, and the positive side busbar are connected. The first diode and the first recovery capacitor to be connected, and the connection point of the snubber diode and the snubber capacitor, which are connected in parallel to the fourth self-arc-extinguishing semiconductor element to form the snubber circuit, and the negative side busbar are connected. A second diode and a second recovery capacitor to connect,
Energy is taken out from each of the first and second recovery capacitors and is regenerated to the positive side and the negative side of the DC power source divided at the intermediate potential point, and the second energy regeneration circuit. , The third self-extinguishing type semiconductor element is connected in parallel, and the connection point of the snubber capacitor and the snubber diode, which constitutes the snubber circuit, and the output terminal or the intermediate potential point are individually provided through a common reactor. With the primary side or auxiliary switch of the transformer to be connected,
A three-level inverter device, characterized in that a rectifying circuit connected between the intermediate potential point and the positive or negative side of the DC power source is provided on the secondary side of each of the transformers.