JP3229931B2 - 3-level power converter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-level power converter, and more particularly, to a technology for reducing the internal inductance of the device.

[0002]

2. Description of the Related Art FIG.
Of the conventional three-level power conversion device described in
FIG. 3 is a configuration diagram showing element arrangement and inter-element connection in a main circuit for each phase. In the figure, 7 and 8 are capacitors connected in series with each other to constitute a DC voltage source 9, P, C1
(C2) and N are the positive terminal of the DC voltage source 9, respectively.
These are an intermediate terminal and a negative terminal. 1a and 1b, 2a and 2
b, 3a and 3b, 4a and 4b are IGBTs connected in parallel to each other, and these IGBTs 1a, 1b and 2
a, 2b and 3a, 3b and 4a and 4b are connected in series with each other. The collectors of the IGBTs 1a and 1b are connected to the positive terminal P, and the emitters of the IGBTs 4a and 4b are connected to the negative terminal N, respectively. A flywheel diode is connected to each IGBT in anti-parallel.

[0003] Reference numerals 5a and 5b, 6a and 6b denote first and second coupling diodes connected in parallel with each other,
The cathodes of the first coupling diodes 5a and 5b are IGBT
At the connection point between 1a, 1b and 2a, 2b, the anode is connected to the intermediate terminal C1 (C2), and the cathode of the second coupling diode 6a, 6b is connected to the intermediate terminal C1 (C2).
The anodes are connected to the connection points of the IGBTs 3a, 3b and 4a, 4b, respectively. O is IGBT2a, 2b and 3
AC output terminals drawn from the connection points a and 3b.

[0004] A detailed description of the commutation operation in the three-level power converter will be given later, but FIG.
The current paths for IGBTs 1 and 2 are shown briefly.
In the figure, L1 to L5 are wiring inductances existing in the main circuit. Here, when the IGBT 1 is turned off from the state where both the IGBTs 1 and 2 are on, that is, when the IGBT 1 is commutated from the current to the current, the voltage of the capacitor 7 + V1 + V2 + V3 is applied to the IGBT 1 by the voltage induced in each wiring inductance. It is applied as a voltage. Also, IGBT2 is turned off and IGBT3,4
When the flywheel diode is turned on, that is, commutates from current to current, the voltage of the capacitor 7 + V2 + V3 + V5 is applied to the IGBT 2 as a surge voltage. This is called a turn-off surge voltage. Unless this turn-off surge voltage is controlled within the safe operation area of the IGBT, the IGBT will be destroyed.

[0005]

In the case of the conventional three-level power converter, as shown in FIG. 18, each coupling diode is arranged on the side of each IGBT connected in series. The value of the inductance is likely to be large, and thus the turn-off surge voltage is high. As a method of suppressing this turn-off surge voltage, there is a method of connecting a snubber circuit that absorbs the energy of the wiring inductance using a separate capacitor in parallel with each IGBT. However, if the wiring inductance is large, a snubber circuit that absorbs the energy is used. The capacitance of the capacitor also increases,
This leads to an increase in device loss, an increase in the size of the device, an increase in device cost, and a decrease in reliability due to an increase in the number of components.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a three-level power converter capable of reducing wiring inductance and suppressing a turn-off surge voltage. .

[0007]

According to a first aspect of the present invention, there is provided a three-level power converter comprising: a DC voltage source having a positive terminal, an intermediate terminal, and a negative terminal; A positive arm having first and second switching elements connected thereto, and a first coupling diode connected between the connection point of the first and second switching elements and the intermediate terminal; and Third and fourth switching elements sequentially connected in series between the AC output terminal and the negative electrode terminal, and a third switching element connected between the third and fourth switching elements and the intermediate terminal. And a negative-side arm having a second coupling diode for outputting a three-level voltage from the AC output terminal.
In level power converter, in the positive arm portion,
In order from the DC voltage source , the second switching element
1 coupling diode-the first switching element
Placed in line, in the negative-side arm portion, the DC voltage source
In order from the third switching element to the second coupling element.
Iode-Fourth switching element arranged almost linearly
And the switching elements and coupling diodes described above.
Make all the connection parts protrude in one direction, and
A plurality of flat wiring boards that are electrically insulated from each other at corners
Used to make necessary electrical connection between the connection parts .

[0008] A three-level power converter according to a second aspect is characterized in that, in the first aspect, the three-level power converter is connected to one side of the DC voltage source.
The positive arm portion and the negative arm portion are arranged substantially in parallel.

A three-level power converter according to a third aspect of the present invention is the same as the first aspect, except that the DC voltage source is sandwiched therebetween.
The positive arm and the negative arm are arranged on both sides of the DC voltage source.

A three-level power conversion device according to a fourth aspect of the present invention is the three-level power conversion device according to any one of the first to third aspects, wherein each of the switching element and the coupling diode is replaced by:
It is composed of a plurality of switching elements or coupling diodes arranged at an equal distance from a DC voltage source and connected in parallel with each other.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a configuration diagram showing element arrangement and inter-element connection of a three-level power converter according to Embodiment 1 of the present invention. In the figure, 9 is a DC voltage source arranged in the center,
It consists of a series body of capacitors 7 and 8, and has a positive terminal P,
An intermediate terminal C and a negative terminal N are provided. Reference numerals 10 and 11 denote a positive arm portion and a negative arm portion arranged on both sides of the DC voltage source 9 with the DC voltage source 9 interposed therebetween. First, as shown in the figure, the positive side arm unit 10 includes a second IGBT 2, a first coupling diode 5, and a first IGBT 1, which are arranged in this order from the DC voltage source 9 side. The connection terminals C, E, A, and K, which will be described later, are accurately arranged on a substantially straight line. The collector C of the first IGBT 1 is connected to the positive terminal P of the DC voltage source 9, and the emitter E is connected to the second I
It is connected to the collector C of the GBT 2 and the cathode K of the first coupling diode 5. First coupling diode 5
Is connected to the intermediate terminal C of the DC voltage source 9,
The emitter E of the second IGBT 2 is connected to the AC output terminal O.

Next, as shown in the drawing, the negative arm 11 is provided with a third IGBT arranged in order from the DC voltage source 9 side.
3, the second coupling diode 6 and the fourth IGBT 4, and each component is arranged substantially on a straight line. The connection terminals C, E, A, and K are connected to the positive arm 10.
Similar to the above, they are arranged exactly on a straight line. And the third
The collector C of the IGBT 3 is connected to the AC output terminal O, and the emitter E is connected to the collector C of the fourth IGBT 4 and the anode A of the second coupling diode 6. The cathode K of the second coupling diode 6 is connected to the intermediate terminal C of the DC voltage source 9, and the emitter E of the fourth IGBT 4 is connected to the negative terminal N of the DC voltage source 9.

Next, a description will be given of the fact that the wiring inductance can be significantly reduced by adopting the above-described element arrangement. As a premise thereof, the commutation operation of the circuit will be described in detail. FIG. 2 is a circuit configuration diagram of FIG. 1. Here, for convenience, IGBTs 1 to 4 each having a flywheel diode connected in anti-parallel are connected to SW1, SW2, SW3, and SW.
4, and the coupling diodes 5, 6 will be referred to as CD1, CD2.

FIGS. 3 and 4 show current modes (MODE1 to MODE1).
FIG. 6 is a diagram showing each current path in MODE 6). In each drawing, L1 to L5 indicate wiring inductances existing in the main circuit. FIG. 5 shows each mode and each element SW during commutation.
6 is a timing chart showing waveforms of currents flowing through 1 to SW4, CD1, and CD2.

First, in FIG. 3A, SW1, SW
In MODE1, in which the switch 2 is turned on and the switches SW3 and SW4 are turned off, a current flows from the capacitor 7 of the capacitor 7, the wiring inductance L1, the SW1, the SW2, and the AC output terminal O (current). In the switching state of each IGBT shown in the upper part of FIG. 5, ○ indicates ON and X indicates OFF. Next, MO
When changing from DE1 to MODE2, SW1 is turned off, and the current flows from the intermediate terminal C to the wiring inductance L2.
→ coupling diode CD1 → wiring inductance L3 → S
W2 → commutates to the AC output terminal O (current). That is,
Commutation from current to current. At this time, the current flowing to SW1 via the wiring inductance L1 decreases, and conversely, the current flowing to SW2 via the wiring inductances L2, CD1 and L3 increases. Therefore, the voltage due to the current decrease rate -di / dt = -di / dt × L1 = V1
Is induced in the direction of the illustrated arrow. The wiring inductances L2 and L3 respectively have a current increase rate di /
Voltage by dt = di / dt × L2 = V2, di / dt
× L3 = V3 is also induced in the direction of the arrow. Therefore, at the time of this commutation, the voltage of the capacitor 7 + V1 + V2 + V3 is applied to SW1 as a surge voltage.

Next, in FIG. 3B, when the mode changes from MODE2 to MODE3, the current decreases because the switch SW2 is turned off, and the current flowing through the flywheel diodes of the switches SW3 and SW4 via the wiring inductance L5 increases. . As a result, the wiring inductances L2, L
In FIG. 3, the voltage according to the current reduction rate -di / dt = -di
/ Dt × L2 = V2 and −di / dt × L3 = V3 are induced in the direction of the arrow. The wiring inductance L5 has a voltage at the rate of current increase di / dt = di / dt.
× L5 = V5 is induced in the direction of the arrow. Therefore, during this commutation, the voltage of the capacitor 8 + V2 + V is applied to SW2.
A voltage of 3 + V5 is applied as a surge voltage.

So far, reference has been made to SW1 and SW2 of the positive arm, but SW3 and S2 of the negative arm are described.
The same is true for W4. That is, in FIG. 4A, in MODE4 in which SW3 and SW4 are turned on and SW1 and SW2 are turned off, the current flows through the AC output terminal O → SW
3 → SW4 → Wiring inductance L5 → Negative terminal N (current). Next, MODE4 to MODE5
SW4 is turned off, and the current is commutated to the AC output terminal O → SW3 → wiring inductance L4 → coupling diode CD2 → wiring inductance L2 → intermediate terminal C (current). That is, the current is commutated to the current. At this time, the wiring inductance L via SW4
5, the current flowing through the coupling diode CD2 via the wiring inductances L4 and L2 increases. Therefore, the voltage due to the current reduction rate -di / dt = -di / dt ×
L5 is induced in the direction of the arrow. The wiring inductances L2 and L4 have current increase rates di / d respectively.
Voltage by t = di / dt × L2 = V2, di / dt ×
L4 = V4 is induced in the direction of the arrow. Therefore, during this commutation, the voltage of the capacitor 8 + V5 +
The voltage of V2 + V4 is applied as a surge voltage.

Next, in FIG. 4B, when the mode changes from MODE5 to MODE6, the current decreases because the switch SW3 is turned off, and the current flowing through the flywheel diodes of the switches SW1 and SW2 via the wiring inductance L1 increases. . Therefore, the wiring inductance L
2, L4 has a voltage by current reduction rate-di / dt =
−di / dt × L2 = V2, −di / dt × L4 = V4
Is induced in the direction of the arrow. Further, the wiring inductance L1 has a voltage = di based on a current increase rate di / dt.
/ Dt × L1 = V1 is induced in the direction of the arrow. Therefore, at the time of this commutation, the voltage of the capacitor 7 +
The voltage of V2 + V4 + V1 is applied as a surge voltage.

Therefore, in order to reduce the surge voltage (turn-off surge voltage) generated by the commutation operation described above, it is only necessary to reduce the wiring inductance in each of the current paths from the current to the current. Then, in order to reduce the inductance of the current path, first, it is important to (1) shorten the wiring length. And at the same time,
(2) A method is effective in which the current paths are formed by reciprocating paths that are close to each other, and most of the magnetic fields generated by the current flowing through the reciprocating paths cancel each other to reduce the inductance.

FIG. 6 shows the three-level power converter shown in FIG. 1 with current paths for the respective currents.
That is, the current flows from the positive terminal P → IGBT1 → IGBT2 →
Although the path of the AC output terminal O is located on a straight line, the length of the reciprocating path can be reduced by positioning the wiring near the line, and the separation distance of the reciprocating path can be reduced. It can be made extremely small, and the wiring inductance existing in the current path can be greatly reduced.

The current is applied to the intermediate terminal C → the coupling diode 5 →
Although it flows through the path of the AC output terminal O, as can be seen from the figure,
For the same reason as the current, the wiring inductance has a sufficiently small value. The current is applied to the negative terminal N → IG
The current flows through the path of BT4 → IGBT3 → AC output terminal O, and similarly, the wiring inductance has a sufficiently small value. In FIG. 6, the current is omitted for the sake of simplicity, but as in the case of the current 〜, it is easy for all of the wiring inductances to have sufficiently small values. Will be understood.

Next, the specific structure of the wiring between the elements described above will be described. That is, here, a wiring structure using a plurality of flat wiring boards arranged close to each other via an insulating plate is adopted. FIG. 7 is a diagram showing the entire structure of the three-level power conversion device shown in FIG. 1 and is a side view as seen from a direction parallel to the plane of the wiring board. In the figure,
The lower stage 20 is, for example, a cooler adopting a water cooling system, and the IGBTs 1, 2, 3, 4 and the coupling diodes 5, 6 are mounted on the upper surface thereof to absorb the heat generated. Therefore, all the connection terminals of the elements 1 to 6 are provided so as to protrude upward.

The condensers 7 and 8 are arranged on the upper left and right sides by means of a fixture (not shown). Reference numeral 30 denotes a group of wiring boards for connecting the capacitors 7, 8 and each of the IGBTs 1 to 4, the coupling diodes 5, 6 and the AC output terminal O, and the structure thereof will be described in more detail with reference to FIGS. 8 is a side view clearly showing the connection relationship between the wiring board group 30 and each terminal, FIG. 9 is a plan view of each wiring board viewed from above, and FIG. It is a perspective view shown. In FIG. 8, a solid line indicates a wiring board, and a dashed line indicates an insulating board. Further, in FIG. 10, the negative arm portion in FIG. 10B is shown in a posture in which the actual arm is rotated by 180 ° for convenience of illustration. Further, in FIGS. 9 and 10, the portion where the terminal portion is blacked out indicates an electrical contact portion. Also,
The open circles on the wiring boards in both figures indicate through holes.

In these figures, wiring board 31 connects positive terminal P to collector terminal C of IGBT 1. The wiring board 32 connects the negative terminal N to the emitter terminal E of the IGBT 4. Wiring boards 33 and 34 are arranged below these wiring boards 31 and 32 via an insulating plate 38. The wiring board 33 connects the intermediate terminal C to the anode terminal A of the coupling diode 5, and the wiring board 34 connects the intermediate terminal C to the cathode terminal K of the coupling diode 6.

Further, wiring boards 35, 36, 37 are arranged below the wiring boards 33, 34 via an insulating plate 38.
Among them, the wiring board 35 connects the emitter terminal E of the IGBT 1, the cathode terminal K of the coupling diode 5 and the collector terminal C of the IGBT 2. Wiring board 36 is connected to emitter terminal E of IGBT 3 and anode terminal A of coupling diode 6 and IG
Connect to collector terminal C of BT4. Also, the wiring board 3
7 is an AC output terminal O and emitter terminals E and I of the IGBT 2
The collector terminal C of the GBT 3 is connected.

As described above, the connections between the terminals are connected by the flat wiring board group 30, and the wiring boards 31 to 37 constituting the wiring board group 30 are laminated with each other via the insulating plate 38. Therefore, the wiring inductance of each current path is further reduced in combination with the arrangement of the terminals described with reference to FIG. That is, the current flows in the wiring board in a distributed manner so that the inductance is minimized, and the reduction of the inductance is thoroughly performed. As a result, the turn-off surge voltage can be reduced, so that a snubber circuit is not required, and the reliability of the device is improved by reducing the size, the loss, and the price of the device, and by reducing the number of components.

Embodiment 2 FIG. FIG. 11 is a configuration diagram showing element arrangement and inter-element connection of a three-level power conversion device according to Embodiment 2 of the present invention. The points common to the first embodiment are omitted, and different points will be mainly described. Here, the positive arm 10 and the negative arm 11 are arranged on the same side of the DC voltage source 9 in parallel with each other. However, in the positive arm section 10, the IGBT 2, the coupling diode 5, and the I
The GBT 1 is disposed, and the IGBT 3, the coupling diode 6, and the IGBT 3 are sequentially arranged in the negative arm 11 from the DC voltage source 9 side.
The point that the BT 4 is arranged is the same as in the first embodiment.

FIG. 12 is a diagram in which currents, currents, and current paths are added to the arrangement connection side in FIG. 11 in accordance with the procedure of FIG. As in the case of the first embodiment, it can be seen that each current path is formed by reciprocating paths that are close to each other. Therefore, it is possible to reduce the wiring inductance.

FIG. 13 is a plan view showing each wiring board when the terminals of FIG. 11 are connected by a wiring board group. Since the connection structure using the wiring board has been described in detail with reference to FIGS. 7 to 10 of the first embodiment, the outline thereof will be described only with reference to FIG. In the drawing, the terminals are blacked out to indicate electrical contact portions, and the terminals of each IGBT are each composed of three terminals connected in parallel. In addition, though a through hole is necessary for each wiring board, it is not shown in FIG.

The wiring board 41 shown in FIG.
The collector terminal C of the GBT 1 is connected. The wiring board 42 in FIG. 4B has a negative terminal N and an emitter terminal E of the IGBT 4.
And connect. The wiring board 43 of FIG. 3C connects the emitter terminal E of the IGBT 1, the cathode terminal K of the coupling diode 5, and the collector terminal C of the IGBT 2. The wiring board 44 connects the collector terminal C of the IGBT 4 to the anode terminal A of the coupling diode 6 and the emitter terminal E of the IGBT 3. The wiring board 45 in FIG. 4D connects the intermediate terminal C, the anode terminal A of the coupling diode 5 and the cathode terminal K of the coupling diode 6. The wiring board 46 shown in FIG. 4E is composed of the AC output terminal O, the emitter terminal E of the IGBT 2 and the IGB.
Connect to collector terminal C of T3.

The wiring boards 41 to 46 are stacked on each other with an insulating plate interposed therebetween. As described in the first embodiment, the adoption of this wiring board group ensures a low inductance and suppresses a turn-off surge voltage. This is possible.

Embodiment 3 FIG. FIG. 14 is a configuration diagram showing element arrangement and inter-element connection of a three-level power conversion device according to Embodiment 3 of the present invention. What differs from FIG. 1 of the first embodiment is that each of the IGBTs 1 to
4. Coupling diodes 5 and 6 each have a configuration in which two elements are connected in parallel. That is, the present invention is applied to a power converter having a higher current rating than that of the first embodiment. The two elements connected in parallel are suffixes a and b
It is represented by FIG. 15 is a circuit configuration diagram thereof.

FIG. 16 is obtained by adding current, current, and current paths to the arrangement and connection example of FIG. However,
In order to avoid complication in the drawing, only one of the parallel elements (b side) is shown, but the other (a side) has exactly the same path. Also in this case, each current path is formed by reciprocating paths that are close to each other, and therefore, it is possible to reduce the wiring inductance.

FIG. 17 is a plan view showing each wiring board when the terminals of FIG. 14 are connected by a wiring board group. In the drawing, the terminals are blacked out to indicate electrical contact portions, and the terminals of each IGBT are each composed of three terminals connected in parallel with each other. In addition, though a through hole is necessary for each wiring board, it is not shown in FIG. The wiring board 51 in FIG. 6A connects the intermediate terminal C, the anode terminals A of the coupling diodes 5a and 5b, and the cathode terminals K of the coupling diodes 6a and 6b.
That is, the wiring board 51 performs both series connection and parallel connection between elements, and the same applies to the following wiring boards. The wiring board 52 in FIG. 4B has an AC output terminal O and the IGBT 2a,
2b and the collector terminals C of the IGBTs 3a and 3b.

The wiring board 53 shown in FIG.
The collector terminals C of the GBTs 1a and 1b are connected, and the wiring board 54 connects the negative terminal N to the emitter terminals E of the IGBTs 4a and 4b. The wiring board 55 in FIG.
Both emitter terminals E of T1a and T1b and coupling diode 5
a, 5b are connected to the collector terminals C of the IGBTs 2a, 2b, and the wiring board 56 is connected to the IGBT 3
a, 3b and the coupling diodes 6a, 6
b, and both collector terminals C of the IGBTs 4a and 4b.

The wiring boards 51 to 56 are stacked on each other with an insulating plate interposed therebetween. As described in the first embodiment, by adopting this wiring board group, the inductance is thoroughly reduced, the turn-off surge voltage is small, and A large-capacity three-level power converter can be realized.

In the above description, the case where the IGBT is used as the switching element has been described. However, the present invention can be similarly applied to other switching elements, for example, a transistor, an intelligent power module, an FET, or the like. It works. Further, the number of parallel elements is not limited to the two described in the third embodiment.

[0038]

As described above, the three-level power converter according to the first aspect comprises a DC voltage source having a positive terminal, an intermediate terminal, and a negative terminal, and a series connection between the positive terminal and the AC output terminal. A first arm connected to the first and second switching elements, and a first coupling diode connected between the connection point of the first and second switching elements and the intermediate terminal; A third and a fourth switching element sequentially connected in series between the AC output terminal and the negative electrode terminal; and a connection between the connection point of the third and the fourth switching element and the intermediate terminal. And a negative-side arm having a second coupling diode for outputting a three-level voltage from the AC output terminal.
In level power converter, in the positive arm portion,
In order from the DC voltage source , the second switching element
1 coupling diode-the first switching element
Placed in line, in the negative-side arm portion, the DC voltage source
In order from the third switching element to the second coupling element.
Iode-Fourth switching element arranged almost linearly
And the switching elements and coupling diodes described above.
Make all the connection parts protrude in one direction, and
A plurality of flat wiring boards that are electrically insulated from each other at corners
Since the structure is used to perform the necessary electrical connection between the connection parts, the wiring inductance in each current path is reduced, and the turn-off surge voltage can be suppressed.

Further, in the three-level power converter according to the present invention , the positive side arm and the negative side are connected to one side of the DC voltage source.
Since the arm and the arm are arranged substantially in parallel, the wiring inductance is small and the plane size is also small.

Further, the three-level power converter according to claim 3 is arranged such that the DC voltage source is interposed between the positive side arm and the three-level power converter.
Since the negative arm and the negative arm are arranged on both sides of the DC voltage source, the wiring inductance is small and the plane width dimension is small.

Further, in the three-level power converter according to the fourth aspect, each of the switching elements and the coupling diodes is provided with a plurality of switching elements or coupling diodes arranged equidistant from the DC voltage source and connected in parallel with each other. , It is possible to realize a large-capacity three-level power conversion device with small wiring inductance.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing element arrangement and inter-element connection of a three-level power converter according to Embodiment 1 of the present invention.

FIG. 2 is a circuit configuration diagram of FIG. 1;

FIG. 3 is a diagram showing a current path in each current mode.

FIG. 4 is a diagram showing a current path in each current mode.

FIG. 5 is a timing chart showing each element current waveform in each mode and commutation.

FIG. 6 is a diagram in which each current path is added to FIG.

FIG. 7 is a diagram showing the overall structure of the three-level power converter of FIG. 1;

FIG. 8 is a side view showing a connection structure using a wiring board group.

FIG. 9 is a plan view of each wiring board viewed from above.

FIG. 10 is a perspective view showing the respective wiring boards and insulating boards separated from each other.

FIG. 11 is a configuration diagram showing element arrangement and inter-element connection of a three-level power converter according to Embodiment 2 of the present invention.

FIG. 12 is a diagram in which each current path is added to FIG. 11;

FIG. 13 is a plan view of each wiring board viewed from above.

FIG. 14 is a configuration diagram showing element arrangement and inter-element connection of a three-level power converter according to Embodiment 3 of the present invention.

FIG. 15 is a circuit configuration diagram of FIG. 14;

FIG. 16 is a diagram in which each current path is added to FIG.

FIG. 17 is a plan view of each wiring board as viewed from above.

FIG. 18 is a configuration diagram showing element arrangement and inter-element connection of a conventional three-level power converter.

FIG. 19 is a circuit configuration diagram of FIG. 18;

[Explanation of symbols]

1, 1a, 1b First IGBT, 2, 2a, 2b Second IGBT, 3, 3a, 3b Third IGBT, 4,
4a, 4b Fourth IGBT, 5, 5a, 5b First coupling diode, 6, 6a, 6b Second coupling diode, 7, 8 Capacitor, 9 DC voltage source, 10 Positive arm, 11 Negative arm Part, 30 wiring board group, 31
To 37, 41 to 46, 51 to 56 Wiring board, 38 insulating board, P positive terminal, N negative terminal, C, C1, C2 intermediate terminal, O AC output terminal.

(56) References JP-A-10-201249 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H02M 7/5387 H02M 1/00

Claims (4)

(57) [Claims] A DC voltage source having a positive terminal, an intermediate terminal, and a negative terminal; first and second switching elements sequentially connected in series between the positive terminal and the AC output terminal; A positive arm having a first coupling diode connected between the connection point of the second switching element and the intermediate terminal; and a serial connection in series between the AC output terminal and the negative terminal. And a second coupling diode connected between the connection point of the third and fourth switching elements and the intermediate terminal, and a negative-side arm unit having:
In the three-level power converter that outputs a three-level voltage from the AC output terminal, the positive-side arm unit includes a second power supply unit that sequentially outputs a second voltage from the DC voltage source .
Switching element-first coupling diode-first switch
The switching elements are arranged on a substantially straight line, and the third switch is arranged in the negative arm section in order from the DC voltage source.
Element-second coupling diode-fourth switching
Arrange the elements almost in a straight line, and make sure that all of the above switching elements and coupling diodes
Project the connection part in one direction, and at a right angle to the one direction
Uses multiple flat wiring boards that are electrically insulated from each other
And a required electric connection between the connecting portions . 2. A direct voltage source having a positive arm on one side thereof.
2. The three-level power converter according to claim 1, wherein the negative arm is disposed substantially in parallel with the negative arm . 3. A positive-side arm sandwiching a DC voltage source.
2. The three-level power conversion device according to claim 1, wherein the unit and the negative arm are arranged on both sides of the DC voltage source. 4. Each switching element and coupling diode
Of the DC voltage source are equidistant from the DC voltage source.
Switching elements or couplings connected in parallel to
The three-level power converter according to any one of claims 1 to 3, comprising a diode .