JP3275132B2 - 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 power converter, and more particularly, to a power converter in which four switching elements are connected in series.
The present invention relates to a power converter suitable for use as a level series multiplex power converter.

[0002]

2. Description of the Related Art As a device using a power converter, a converter device for converting AC to DC and an inverter device for converting DC to AC are known. The converter device and the inverter device are used, for example, as an uninterruptible power supply device, and the inverter device is used, for example, to drive an induction motor used in a mill, a fan, a pump, or the like of a rolling equipment plant at a variable speed. I have.

Conventionally, as this type of inverter device,
There is known an induction motor in which the temporary voltage and frequency are variably controlled to perform variable speed control. However, one self-extinguishing element such as a transistor is provided as a switching element for the upper and lower arms. When the induction motor is controlled at a variable speed using such an inverter device, a large current flows through each switching element of the upper and lower arms, and a high voltage is applied to the switching element when the switching element is turned off or the power switch is turned off. Sometimes. This voltage increases as the inductance of the circuit wiring increases. For example, Japanese Patent Application Laid-Open Nos. 1-61028 and 4-674 describe a method for reducing the wiring inductance.
No. 36, Japanese Patent No. 2531928, a plurality of signal lines are arranged close to each other, a plurality of signal lines are twisted with each other, or a circuit is divided into a plurality of conductors and formed. A direction in which conductors are stacked via an insulator has been proposed.

[0004]

In the prior art,
Though consideration is given to reducing the wiring inductance of the power converter in which the switching elements of the upper and lower arms are each configured as a single unit, a so-called three-level series multiplex inverter in which four switching elements are connected in series. There is not enough consideration in reducing the wiring inductance of the device. That is, in the three-level serial multiplex inverter device, since the operation mode of the switching element is different from that of the former power converter, even if the method of the related art is adopted, the inductance due to the wiring cannot be sufficiently reduced.

An object of the present invention is to provide a power converter and a power conversion device that can suppress the influence of inductance due to wiring.

[0006]

In order to achieve the above object, the present invention provides a power supply system comprising a plurality of DC power supplies connected in series between a positive terminal and an output terminal connected to a load. A positive-side main switching element and a positive-side auxiliary switching element connected in series, and a negative-side main switching element and a negative side inserted between the negative terminal and the output terminal of the DC power supply and connected in series with each other; The auxiliary switching element, the positive connection point of the positive main switching element and the positive auxiliary switching element is the cathode side, and the neutral point where the plurality of DC power supplies are connected in series with each other is the anode side, and the positive connection point is The positive side rectifying element connected to the neutral point, the negative side connection point of the negative side main switching element and the negative side auxiliary switching element is the anode side, and the neutral point is the cathode side. A negative rectifying element connected to the negative connection point and the neutral point, the positive main switching element is connected to a positive terminal of the DC power supply, and the positive auxiliary switching element is A power converter connected to an output terminal, the negative-side main switching element connected to a negative-side terminal of the DC power supply, and the negative-side auxiliary switching element connected to the output terminal; conductor pattern connecting the first connection conductor plate, the cathode side of the anode side and the negative-side rectifying elements of the said neutral point positive rectifying element having a first conductor pattern connecting with the positive side main switching and The positive side main switch
The switching element or the negative main switching element is turned off.
A second connection conductor plate having a second conductor pattern belonging to a circuit having a large current change when the second connection conductor plate is provided, and a third conductor pattern connecting a negative terminal of the DC power supply and the negative main switching element. A third connection conductor plate, and a first connection conductor plate and a third connection conductor plate are laminated separately above and below the second connection conductor plate via an insulating member; The conductor pattern is formed so as to include a region overlapping with the second conductor pattern in the lamination direction, and each of the elements is mounted on one of the first to third connection conductor plates. A power converter is characterized in that each element is connected in a specified pattern.

In configuring the power converter, a fourth conductor pattern having a fourth conductor pattern for connecting the respective elements to each other with reference to the positive connection point and the negative connection point and the output terminal is provided.
Is provided, and the fourth connection conductor plate is laminated on the first connection conductor plate or the third connection conductor plate side, and is connected to any one of the first to fourth connection conductor plates. Each element can be mounted, or each element can be mounted only on the fourth connection conductor plate.

In configuring the power converter, a plurality of positive-side main switching elements, positive-side auxiliary switching elements, negative-side main switching elements, negative-side auxiliary switching elements, positive-side rectifying elements, and negative-side rectifying elements are provided. The connection conductor plates are provided and multiplexed, and each connection conductor plate can be added with an element formed with a number of conductor patterns corresponding to the multiplexing.

[0009] A power converter comprising a control means for controlling the switching operation of the positive side main switching element, the positive side auxiliary switching element, the negative side main switching element and the negative side auxiliary switching element together with any one of the power converters. It can also be configured.

According to the above-mentioned means, the first and third conductor patterns are formed so as to include an overlapping area in the laminating direction of the second conductor patterns, and the first to third conductor patterns form the insulating member. The first layer
This means that the third conductor patterns are arranged close to each other. In addition, in any of the operation modes, a current flows through the second conductor pattern. Therefore, since the first conductor pattern and the third conductor pattern are separately arranged on both sides of the second conductor pattern, each switching operation is performed. The effective inductance (self-inductance-mutual inductance) can be reduced by the mutual inductance effect according to the operation of the element. When the self-inductance decreases, the level of the voltage applied to both ends of the switching element when the switching element is turned off can be reduced,
The effect of wiring inductance can be suppressed,
This can contribute to improvement in the reliability of the switching element.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a configuration diagram of a connection conductor plate of a power converter showing one embodiment of the present invention, FIG. 2 is a pattern configuration diagram formed on the connection conductor plate, and FIG. 3 is an overall configuration diagram of a series multiplex inverter device. It is.

In FIG. 3, a serial multiplex inverter device is a three-level serial multiplex inverter device, for example,
In order to drive the induction motor 3 used for the mill, fan, pump and the like of the rolling equipment plant at a variable speed, three-phase main circuits 1a, 1b, and 1c are provided as power converters for three phases. A drive circuit 4 and a control circuit 5 are provided as control means for controlling the switching operation of the switching elements constituting the circuit. The three-phase main circuits 1a to 1c are configured as U-phase, V-phase, and W-phase power converters, respectively, and each circuit has the same configuration. Therefore, only the three-phase main circuit 1a will be described below.

The three-phase main circuit 1a is a self-extinguishing type switching element, for example, a bipolar transistor QP,
It has QPC, QNC, and QN. Transistor QP
Is connected to the positive terminal P among terminals in which a plurality of DC power supplies are connected in series. The transistor QP is connected in series with the transistor QPC via the positive connection point 6. The emitter of the transistor QPC is connected to the output terminal U and to the collector of the transistor QNC. Transistor Q
The NC is connected in series with the transistor QN via the negative connection point 7. The emitter of the transistor QN is connected to the negative terminal N of the DC current. The transistor QP is a transistor QP serving as a positive-side main switching element.
PC is configured as a positive auxiliary switching element, transistor QNC is configured as a negative auxiliary switching element, and transistor QN is configured as a negative switching element. Diodes D1 to D4 are connected in anti-parallel between the emitter and collector of each transistor. Have been. These diodes D1 to D4 are connected to transistors QP to QN.
Is built into the device. A clamp diode DP as a positive rectifying element is inserted between the positive connection point 6 and the neutral point C of the DC power supply. The cathode of the diode DP is connected to the positive connection point 6, and the anode of the diode DP is neutral. Connected to point C. A clamp diode DN as a negative-side rectifying element is inserted between the negative-side connection point 7 and the neutral point C. The diode DN has a cathode connected to the neutral point C, and an anode connected to the negative-side connection point. 7 is connected. A smoothing capacitor 2a is inserted between the positive terminal P and the neutral point C, and a smoothing capacitor 2a is connected between the neutral point C and the negative terminal N.
b is inserted.

On the other hand, a switching signal is input to the base of each of the transistors QP to QN via the control circuit 5 and the drive circuit 4, and a positive signal is applied to the positive terminal P with respect to the neutral point C. When each of the transistors QP to QN performs a switching operation in a specified operation mode in a state in which a DC voltage is applied to the negative terminal N and an AC voltage is generated in the output terminal U, The induction motor 3 is controlled at a variable speed by the voltage. For example,
When the transistors QNC and QN are off,
After the transistor DP is turned on, the transistor QP
Is turned on, a positive voltage is generated at the output terminal U. When the transistors QP and QPC are turned off, the transistor QNC is turned on and then the transistor QN is turned on.
When C is turned on, a negative voltage is generated at the output terminal U.

In the process of operating each transistor, specifically, a current as shown in FIG. 4A flows through the circuit.
For example, when both the transistors QNC and QN are off and the transistor QP is turned on after the transistor QPC is turned on, a current flows through the route of the positive terminal P → the transistor QP → the transistor QPC → the output terminal U. . The current flowing at this time has a relationship of ip = iu. The current iu is supplied to the induction motor 3 and this current iu
Indicates a current change characteristic determined by the inductance of the induction motor 3.

From such an initial state, the transistor Q
When only P is turned off, as shown at timing t1,
The current flowing through the transistor QP moves to the clamp diode DP. That is, neutral point C, diode D
A current ic flows through a route connecting P, the transistor QPC, and the output terminal U. As shown in FIG. 4B, at this time, the change in the current flowing through the positive terminal P and the neutral point C is large, but the change in iu flowing through the output terminal U is small.

Next, when the transistors QP and QPC are off and the transistor QNC is turned on and then turned on, the output terminal U and the transistor QNC are turned off as shown in FIG. , The current in flows through a route connecting the transistor QN and the negative terminal N. When only the transistor QN is turned off at the timing t2, the current flowing through the transistor QN flows to the neutral point C via the clamp diode DN. That is, after the timing t2, the current ic 'flows to the neutral point C.
Also at this time, the change in the current flowing through the neutral point C and the negative terminal N is large, but the change in iu ′ flowing through the output terminal U is small.

As described above, as shown at timings t1 and t2, when the transistor in the on state is turned off,
A voltage as shown in FIG. 5 is applied between the emitter and the collector of the turned-off transistor. This voltage is
When the inductance due to the wiring is small, the voltage shows a small value ΔV1, and as the inductance increases, it shows a large value ΔV2. Therefore, it is necessary to reduce the inductance due to the wiring.

Therefore, in this embodiment, when mounting transistors and diodes, a real-phase structure as shown in FIGS. 1 and 2 is employed. That is, each element constituting the three-phase main circuit 1a is mounted on the four connection conductor plates 10 to 16. On the connection conductor plate 12, a first conductor pattern 18 connecting the positive terminal P and the collector of the transistor QP is formed as a first connection conductor plate. The connection conductor plate 14 has a neutral point C as a second connection conductor plate.
Conductor pattern 20 connecting the anode of clamp diode DP and the cathode of clamp diode DN
Are formed. On the connection conductor plate 16, a third conductor pattern 22 connecting the negative terminal N and the emitter of the transistor QN is formed as a third connection conductor plate. The connection conductor plate 10 includes, as fourth connection conductor plates, fourth connection patterns 24, 2 for connecting the respective elements to each other with reference to the positive connection point 6, the output terminal U, and the negative connection 7.
6, 28 are formed. Further, the connection conductor plate 1
0 includes transistors QP to QN, diodes DP, DN
Has been implemented. Each of the conductor patterns 18 to 28 is formed in accordance with a route through which a current flows.
The conductor patterns 18 and 22 are formed in a shape including a region overlapping each other in a region in the stacking direction with reference to 0. That is, the conductor patterns 18 and 22 are formed so as to be arranged close to the conductor pattern 20 when the connection conductor plates are stacked.

When laminating the connection conductor plates, FIG.
As shown in (b), the connection conductor plate 12 is laminated on the connection conductor plate 14 via an insulating member 32, and the connection conductor plate 1
The connection conductor plate 16 is laminated on the lower side of 4 via an insulating member 34. Further, the insulating member 3 is provided on the connection conductor plate 12.
0, the connection conductor plate 10 is connected. The distance between the centers of the connection conductor plates 10 to 16 is set to d. When the connection conductors 10 to 16 are stacked, the conductor patterns 18 to 28 and the elements are connected via conductors inserted into the through holes of the connection conductor plates 10 to 16.

As described above, according to the present embodiment, the conductor patterns 20 and 22 are divided above and below the conductor pattern 20 belonging to the circuit having a large current change when the transistors QP and QN are turned off. Since they are arranged, the influence of inductance due to wiring can be suppressed.

Specifically, when the transistor QP is turned off, the voltages ΔV1 and V2 applied across the transistor QP depend on the inductance of the circuit connecting the positive terminal P and the collector of the transistor QP. The voltages ΔV1 and V2 are expressed by the following equation (1).

ΔV1, ΔV2∝LP_QP (1) Here, LP_QP indicates an inductance of a circuit connecting the control terminal P and the collector of the transistor QP.

From equation (1), when LP_QP is small, the rise in voltage is small, as in ΔV1, and when LP_QP is large, the rise in voltage is large, as in ΔV2.

On the other hand, LP_QP can be separated into self-inductance and mutual inductance as shown in the following equation (2).

LP_QP = LP_QPs + MC_QP_PC (2) where LP_QPs is the control terminal P and the transistor QP
And MC_QP_
PC indicates a mutual inductance between a circuit connecting the positive terminal P and the transistor QP and a circuit connecting the neutral point C and the diodes DP and DN.

From equation (2), to reduce LP_QP (equal inductance), the mutual inductance MC_QP_P between the neutral point C and the circuit including the transistor QP is determined.
It can be seen that reducing C is effective. The mutual inductance MC_QP_PC is inversely proportional to the distance between the circuit connecting the positive terminal P and the transistor QP and the circuit connecting the neutral point C and the diodes DP and DN. Therefore, by arranging the conductor pattern 20 and the conductor pattern 18 close to each other, the mutual inductance can be reduced. Similarly, by arranging the conductor pattern 20 and the conductor pattern 22 close to each other, the mutual inductance between the conductor pattern 20 and the conductor pattern 22 can be reduced. In addition,
The distance d is a physical minimum distance determined by the thickness of the connection conductor plate, and the voltage between terminals applied to the transistors QP and QN when the transistors QP and QN are off can be suppressed to a small voltage by the mutual inductance effect.

Further, according to the present embodiment, a rise in the voltage that occurs when the transistor is turned off can be suppressed, so that the rated voltages of the transistors QP to QN can be reduced. Even when a snubber circuit is provided for each of the transistors QP to QN, the size of each snubber circuit can be reduced. Further, since the same element is used as each of the transistors QP to QN, the rated current of each transistor can be increased.

Next, another embodiment of the present invention will be described with reference to FIGS.

In this embodiment, in order to multiplex various circuit elements, transistors Q connected in series with each other are used.
Transistors QP2, QPC2, QNC connected in series with each other in parallel with P1, QPC1, QNC1, QN1
2, QN2 are connected in series with each other, and the positive connection points 6a, 6
b and a neutral diode C
1, DP2 are inserted, and clamp diodes DN1, DN2 are inserted between the negative connections 7a, 7b and the neutral point C, respectively. Each circuit element is mounted on four connection conductor plates as in the above-described embodiment, and each conductor plate is formed with a pair of conductor patterns 18 to 28. In this case, each of the conductor patterns 18 and 22 is vertically arranged on the basis of each of the conductor patterns 20.

Also in this embodiment, each conductor pattern 2
Since the conductor patterns 18 and 22 are arranged close to each other with reference to 0, the effective inductance is reduced, and it is possible to suppress an increase in voltage due to the wiring inductance.

In each of the above embodiments, if the conductor patterns 18 and 22 are arranged above and below the conductor pattern 20, the effective inductance can be reduced. It is also possible to dispose the connection conductor plate 18 on the lower side. The connection conductor plate 10 can be arranged either above or below the connection conductor plates 12 to 16. Further, each circuit element can be mounted on any of the connection conductor plates.

Further, in the above-described embodiment, the case where the power converter is used for the inverter device has been described. However, the power converter can be used for the converter device.

[0035]

As described above, according to the present invention,
Since the first and third conductor patterns are separately laminated on both sides of the second conductor pattern, and the first and third conductor patterns are formed so as to include a region overlapping with the second conductor pattern in the laminating direction. The effect of the wiring inductance can be suppressed, and an increase in the voltage applied between the terminals of the switching element can be suppressed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a connection conductor plate of a power converter according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a conductor pattern of a connection conductor plate.

FIG. 3 is an overall configuration diagram of a serial multiplex inverter device.

FIG. 4 is a diagram for explaining a state of a current flowing in a main circuit.

FIG. 5 is a waveform chart showing a state of a change in terminal voltage of a transistor.

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

FIG. 7 is a diagram showing a conductor pattern of the power converter shown in FIG.

[Explanation of symbols]

 1a, 1b, 1c Three-phase main circuit 2a, 2b Smoothing capacitor 3 Induction motor 4 Drive circuit 5 Control circuit 10, 12, 14, 16 Connection conductor plate 18, 20, 22, 24, 26, 28 Conductor pattern 30, 32, 34 Insulation member QP, QPC, QNC, QN Transistor DP, DN Clamp diode

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-8-294266 (JP, A) JP-A 8-214561 (JP, A) JP-A 8-223917 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) H02M 7/48 H02P 7/63 H05K 1/02 H05K 1/14

Claims (5)

(57) [Claims] 1. A positive main switching element and a positive auxiliary switching element inserted between the positive terminals of a plurality of DC power supplies connected in series and an output terminal connected to a load and connected in series with each other. A negative main switching element and a negative auxiliary switching element inserted between the negative terminal and the output terminal of the DC power supply and connected in series with each other; a positive main switching element and a positive auxiliary switching element A positive-side rectifying element connected to the positive-side connection point and the neutral point as a positive-side connection point with the cathode side and a neutral point where the plurality of DC power supplies are connected in series to each other as an anode side, A negative side rectifier connected to the negative side connection point and the neutral point with the negative side connection point between the negative side main switching element and the negative side auxiliary switching element as the anode side and the neutral point as the cathode side A positive side main switching element is connected to a positive side terminal of the DC power supply, the positive side auxiliary switching element is connected to the output terminal, and the negative side main switching element is a negative side of the DC power supply. A power converter connected to a terminal, wherein the negative auxiliary switching element is connected to the output terminal, the power converter having a first conductor pattern connecting a positive terminal of the DC power supply and the positive main switching. A connection conductor plate, and the positive main switch as a conductor pattern connecting the neutral point to the anode side of the positive rectifier element and the cathode side of the negative rectifier element.
The switching element or the negative main switching element is turned off.
A second connection conductor plate having a second conductor pattern belonging to a circuit having a large current change when the second connection conductor plate is provided, and a third conductor pattern connecting a negative terminal of the DC power supply and the negative main switching element. A third connection conductor plate, and a first connection conductor plate and a third connection conductor plate are laminated separately above and below the second connection conductor plate via an insulating member; The conductor pattern is formed so as to include a region overlapping with the second conductor pattern in the lamination direction, and each of the elements is mounted on one of the first to third connection conductor plates. A power converter, wherein each element is connected in a specified pattern. 2. A positive-side main switching element and a positive-side auxiliary switching element which are inserted between the positive terminals of a plurality of DC power supplies connected in series and an output terminal connected to a load and connected in series with each other. A negative main switching element and a negative auxiliary switching element inserted between the negative terminal and the output terminal of the DC power supply and connected in series with each other; a positive main switching element and a positive auxiliary switching element A positive-side rectifying element connected to the positive-side connection point and the neutral point as a positive-side connection point with the cathode side and a neutral point where the plurality of DC power supplies are connected in series to each other as an anode side, A negative side rectifier connected to the negative side connection point and the neutral point with the negative side connection point between the negative side main switching element and the negative side auxiliary switching element as the anode side and the neutral point as the cathode side A positive side main switching element is connected to a positive side terminal of the DC power supply, the positive side auxiliary switching element is connected to the output terminal, and the negative side main switching element is a negative side of the DC power supply. A power converter connected to a terminal, wherein the negative auxiliary switching element is connected to the output terminal, the power converter having a first conductor pattern connecting a positive terminal of the DC power supply and the positive main switching. A connection conductor plate, and the positive main switch as a conductor pattern connecting the neutral point to the anode side of the positive rectifier element and the cathode side of the negative rectifier element.
The switching element or the negative main switching element is turned off.
A second connection conductor plate having a second conductor pattern belonging to a circuit having a large current change when the second connection conductor plate is provided, and a third conductor pattern connecting a negative terminal of the DC power supply and the negative main switching element. A third connection conductor plate, and a fourth connection conductor plate having a fourth conductor pattern for interconnecting the respective elements based on the positive connection point, the negative connection point, and the output terminal. A first connection conductor plate and a third connection conductor plate are laminated separately above and below the second connection conductor plate via an insulating member, and the first and third conductor patterns are formed by the second connection conductor plate. The first connection conductor plate or the third connection conductor plate is formed on the first connection conductor plate or the third connection conductor plate side via an insulating member, and is formed so as to include a region overlapping with the conductor pattern in the stacking direction. Or any one of the fourth connection conductor plates Wherein each element is mounted to the conductive plate, the power converter, characterized in that each element is connected to a specified pattern. 3. A positive-side main switching element and a positive-side auxiliary switching element inserted between the positive terminals of a plurality of DC power supplies connected in series and an output terminal connected to a load and connected in series with each other. A negative main switching element and a negative auxiliary switching element inserted between the negative terminal and the output terminal of the DC power supply and connected in series with each other; a positive main switching element and a positive auxiliary switching element A positive-side rectifying element connected to the positive-side connection point and the neutral point as a positive-side connection point with the cathode side and a neutral point where the plurality of DC power supplies are connected in series to each other as an anode side, A negative side rectifier connected to the negative side connection point and the neutral point with the negative side connection point between the negative side main switching element and the negative side auxiliary switching element as the anode side and the neutral point as the cathode side A positive side main switching element is connected to a positive side terminal of the DC power supply, the positive side auxiliary switching element is connected to the output terminal, and the negative side main switching element is a negative side of the DC power supply. A power converter connected to a terminal, wherein the negative auxiliary switching element is connected to the output terminal, the power converter having a first conductor pattern connecting a positive terminal of the DC power supply and the positive main switching. A connection conductor plate, and the positive main switch as a conductor pattern connecting the neutral point to the anode side of the positive rectifier element and the cathode side of the negative rectifier element.
The switching element or the negative main switching element is turned off.
A second connection conductor plate having a second conductor pattern belonging to a circuit having a large current change when the second connection conductor plate is provided, and a third conductor pattern connecting a negative terminal of the DC power supply and the negative main switching element. A third connection conductor plate, and a fourth connection conductor plate having a fourth conductor pattern for interconnecting the respective elements based on the positive connection point, the negative connection point, and the output terminal. A first connection conductor plate and a third connection conductor plate are laminated separately above and below the second connection conductor plate via an insulating member, and the first and third conductor patterns are formed by the second connection conductor plate. A fourth connection conductor plate is formed on the first connection conductor plate or the third connection conductor plate side via an insulating member, and is formed so as to include a region overlapping with the conductor pattern in the lamination direction. Each element is mounted on a connection conductor plate of Element power converter, characterized in that is connected to the specified pattern. 4. A plurality of positive-side main switching elements, a positive-side auxiliary switching element, a negative-side main switching element, a negative-side auxiliary switching element, a positive-side rectifier, and a negative-side rectifier are provided and multiplexed. 4. The power converter according to claim 1, wherein the connecting conductor plate is formed with a number of conductor patterns corresponding to the multiplexing. 5. The power converter according to claim 1, 2, 3, or 4, further comprising switching for a positive main switching element, a positive auxiliary switching element, a negative main switching element, and a negative auxiliary switching element. A power conversion device comprising control means for controlling operation.