JP2003088098A - Power converter - Google Patents

Abstract

(57) [PROBLEMS] To provide a stable large-current supply and reliable short-circuit protection without oscillation of a gate signal in a power converter in which one arm has a plurality of unit arm elements connected in parallel. The present invention relates to a power converter including a gate drive circuit (12) for supplying an on / off gate signal to each unit arm element. A T-type resistor circuit in which three resistors (R1, R2, R3) are connected in a T-shape is arranged at an output terminal of the gate drive circuit, and a gate line from the output terminal to each unit arm element is branched. A gate signal transmitted via the branched gate line is supplied to the gate of each unit arm element via a gate resistor (Rg) arranged for each unit arm element on the unit arm element side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power converter for supplying variable frequency AC power to an electric motor.

[0002]

2. Description of the Related Art Generally, a power converter for supplying variable frequency AC power to an electric motor comprises a DC power supply and an inverter for converting the DC power into AC of a predetermined frequency. DC power is often obtained from an AC power supply through a converter. FIG. 10 shows a general power conversion device including such a converter and an inverter.

A power converter shown in FIG. 10 is a converter 2 for converting AC power from a three-phase AC power supply 1 into DC power.
And a smoothing capacitor 3 for smoothing the rectified DC power from the converter 2, and an inverter 4 for converting the smoothed DC power into AC power of variable frequency / variable voltage. The AC output of the entire power conversion device is extracted from the AC output terminal of the inverter 4 and supplied to the AC motor 5.

Each arm 2UP, 2VP of the converter 2,
Each of 2WP, 2UN, 2VN, and 2WN is composed of a diode that performs a rectifying function and a switching element that is connected in antiparallel to the diode and that performs an inverter function during regeneration. Similarly, each arm 4UP, 4VP, 4 of the inverter 4
Each of WP, 4UN, 4VN, and 4WN is composed of a switching element for performing an inverter function and a diode connected in antiparallel to the switching element and acting as a rectifier during regeneration. 2 of the 3 alphanumeric symbols representing the arm
The second U, V, and W represent the phases when viewed from the AC side,
The third P and N represent positive and negative when viewed from the DC side (P is the positive side and N is the negative side). The three-phase AC power supply 1 is connected to the three-phase AC terminals R, S, T of the converter 2, and the converter 2
Is connected to the DC buses P and N, and the three-phase AC terminals U, V and W of the inverter 4 are connected to the AC motor 5. The switching element of each arm of the converter 2 and the inverter 4 is a self-extinguishing type switching element,
For example, an IGBT (gate insulation type bipolar transistor) is used.

Each arm is generally composed of a plurality of unit arm elements connected in series and parallel according to a circuit voltage and a circuit current, and the respective unit arm elements are interconnected via a connecting conductor. FIGS. 11 and 12 show an example of a configuration in which each arm is composed of four parallel unit arm elements, taking as an example the arms of converter 2 and inverter 4 for the U phase and one phase. The positive U-phase arm 2UP of the converter 2 shown in FIG. 11 includes four unit arm elements 2UP1, 2UP2, 2UP3, 2UP4 connected in parallel, and the negative U-phase arm 2UN includes four unit arms connected in parallel. It comprises elements 2UN1, 2UN2, 2UN3, 2UN4. The positive side U-phase arm 4UP of the inverter 4 shown in FIG. 12 includes four unit arm elements 4UP connected in parallel.
1, 4UP2, 4UP3, 4UP4, and the negative U-phase arm 4UN is composed of four unit arm elements 4UN1, 4UN2, 4UN3, 4UN4 connected in parallel. Similarly, the smoothing capacitor 3 includes four unit capacitors 3A, 3B, 3C and 3D as shown in FIGS.
Shows an example in which is 2 series and 2 parallel.

13 and 14 show four positive side unit arm elements 4UP1 to 4UP4 and four negative side unit arm elements 4UN1 to 4UN4 of the inverter 4 shown in FIG. 12, and four unit capacitors 3A to 3D. 3 shows a spatial arrangement state of the. The positive and negative unit arm elements are linearly arranged in two rows on the cooling body 8, and four unit capacitors are juxtaposed on that side.

Both unit capacitors 3A and 3B are connected conductors 6.
Connected in series by A, both unit capacitors 3C, 3D
Are connected in series by a connecting conductor 6B, and both ends thereof are connected to the positive side bus P9 and the negative side bus N9, respectively. The AC terminal side (emitter) of the positive side unit arm element 4UP1 and the AC terminal side (collector) of the negative side unit arm element 4UN1 are connected in series by a connecting conductor 7A, and the like, similarly, the positive side unit arm elements 4UP2, 4UP3. 4U
AC terminal side (emitter) of P4 and negative unit arm element 4
AC terminal side (collector) of UN2, 4UN3, 4UN4
Are connected in series by connecting conductors 7B, 7C, 7D. The positive sides (collectors) of the positive side unit arm elements 4UP1 and 4UP2 are connected by the connecting conductor 7E, the negative sides (emitters) of the negative side unit arm elements 4UN1 and 4UN2 are connected by the connecting conductor 7F, and the positive side unit arm element 4 is connected.
The positive side (collector) of UP3, 4UP4 is connected by the connecting conductor 7G, and the negative side unit arm elements 4UN3, 4UN
The negative side (emitter) of 4 is connected by the connecting conductor 7H.

A positive bus P1 and a negative bus N1 are arranged along the converter 2, the capacitor 3 and the inverter 4, and a positive bus P9 and a unit bus between the bus P1 and N1 are connected between the unit capacitor and the unit arm element. The negative side bus N9 is located vertically and branched. Connection conductor 7
E and 7F are connected to the positive side bus P9 via the connection conductors 7I and 7J, and similarly, the connection conductors 7G and 7H are the connection conductors 7
It is connected to the negative side bus N9 via K and 7L. The U-phase output terminals of the connection conductors 7A, 7B, 7C and 7D are led out via connection conductors (not shown).

FIG. 15 is an explanatory view schematically showing a state in which the power conversion device of FIGS. 13 and 14 is housed in a housing 21. Here, the unit arm element 2 of the converter 2 is provided in the housing 21.
UP1, 2UN1, 2UP2, 2UN2, and each arm element 4UP1, 4UN1, 4UP2 of the inverter 4
4UN2 is shown housed together with the gate drive circuit boards 22 and 23, respectively. Although not shown,
The unit smoothing capacitors 3A, 3B and 3C, 3D are distributed in front of and behind the casing 21. Gate drive circuit board 22
The positive and negative element driving signal output ends of the gate resistance Rg are connected to the gate terminals of the unit arm elements of the converter 2.
Similarly, the positive-side and negative-side element driving signal output ends of the gate drive circuit 23 are also connected to the gate terminals of the unit arm elements of the inverter 4 via the gate resistance Rg.

FIG. 16 shows the gate drive circuit boards 22 and 23.
2 shows the drive circuit output part of the unit arm element of the gate drive circuit board 23 and the inverter 4 (only two unit arm elements are illustrated). Gate drive circuit board 2
The gate drive circuit 12 on 3 outputs a gate signal of, for example, + 15V or a gate signal of -15V from the midpoint of connection of the complementary transistors Tr1 and Tr2 in accordance with the positive or negative PWM control signal input from the host controller. A positive (on control) or negative (off control) gate voltage generated across the resistor R3 is applied to each switching element via the gate resistors Rgn1 and Rgn2. This gate voltage is limited by an overvoltage protection means (for example, a Zener diode) ZD connected in parallel with the resistor R3. As is well known, in the normal state, the arm elements on both positive and negative sides of the same phase do not turn on at the same time, and when either one turns on, the other turns off. The gates of the switching elements included in each unit arm element are gate resistors Rgp1 and Rgp connected in series, respectively.
It is connected to the output end of the gate drive circuit 12 via 2, Rgn1, Rgn2 and a connecting wire. Gate drive circuit 1
2, the unit arm elements 4UN1 and 4UN on the negative side are
Only the drive circuit for 2 is shown in detail. Although a detailed circuit is not shown for the positive side unit arm elements 4UP1 and 4UP2, a drive circuit having the same circuit configuration is formed although it is insulated from the negative side circuit. Wirings from the gates of the unit switching elements connected in parallel in two to the gate drive circuit 12 are grouped for each switching element group connected in parallel and guided to the gate drive circuit 12.

In the gate drive circuit 12, both ends of the gate signal power supply 11 with a midpoint are connected to both ends of the series-connected complementary transistors Tr1 and Tr2, and the common connection point of both transistors and the midpoint of the gate signal power supply 11 are connected. A load resistor R3 is connected between the lead resistance R3 and the derived reference potential line 14. A Zener diode ZD is connected in parallel with the resistor R3 as overvoltage protection means. Resistance R3
Gate signal is taken out from both ends of the gate resistance Rgp
1, unit arm elements 4UN1, 4UN via Rgp2
Applied to 2. The gate signal power supply 11 is, for example, 30V as a whole, and is + 15V (when ON) via the gate control means 10 and the transistor Tr1 or Tr2 in response to a positive or negative control signal from the upper control means.
Alternatively, a square wave PWM control signal of -15 V (when off) is applied to the switching elements of the unit arm elements 4UN1 and 4UN2.

[0012]

In a power converter for increasing the capacity by connecting a plurality of elements in parallel, a plurality of switching elements connected in parallel are simultaneously switched by PWM control to supply a large current. However, when a gate-emitter voltage of the switching element is changed in order to reduce or turn off a large current in the event of a short circuit or the like, a gate signal may oscillate and damage the switching element. Further, in order to prevent damage to the element due to malfunction of the switching element due to noise superimposed on the gate signal and overcurrent exceeding the withstand amount, a short circuit detection unit 13 is provided, and when a short circuit is detected, switching of all phases is performed. A short-circuit protection method has been considered in which the gate signals of the elements are once turned on at the same time and then the gate signals are throttled to reduce the current and cut off. However, in the protection operation, when all the phases are turned on once and the gate-emitter voltage of the switching element is reduced, the gate signal 31 oscillates as shown in FIG. 17 and the short-circuit current 32 flows, which may damage the switching element. there were.

All of these cases are common problems that occur when the gate signal is changed when a large current is applied. A factor that causes the gate signal 31 to oscillate is a closed circuit that includes the impedance inside the switching element when the gate signal fluctuates (such as the tail when turned off) and the wiring impedance of the unit-arm element connecting conductors that are connected in parallel. May resonate.

Due to the influence, the oscillation propagates from the gate line on the control side into the substrate, and the gate drive transistor Tr
1, Tr2 flows from the emitter to the base side via the stray capacitance between the base and the emitter, the noise is amplified again and the gate signal becomes oscillating state, and the gate signal line is gated by the switching of large current. If noises are overlapped up to the drive circuit section, the gate signal may be oscillated in the same manner as described above, and the switching element may be damaged.

It is an object of the present invention to provide a power conversion device in which a plurality of unit elements are connected in parallel and which can carry out stable large current conduction and reliable short-circuit protection without oscillation of a gate signal. To provide.

[0016]

According to a first aspect of the present invention, there is provided a power converter comprising a plurality of gate control type unit arm elements in which one arm is connected in parallel, and each unit arm element has an on / off gate. In a power conversion device having a gate drive circuit for supplying a signal, a T-type resistance circuit formed by connecting three resistors in a T-shape is arranged at the output end of the gate drive circuit, and each unit arm element is provided from the output end. To the gate of each unit arm element, and the gate signal transmitted via the branched gate line is supplied to the gate of each unit arm element via the gate resistor arranged on each unit arm element side. It is characterized by doing. According to the present invention, the resistance provided at the output end side of the T-type resistance circuit, that is, the damping resistance, causes the negative side vibration of the switching element forming the arm and the noise overlapping on the gate wiring to the gate drive circuit to be gate driven. Suppress before the circuit,
As a result, the vibration of the emitter of the drive transistor included in the gate drive circuit can be suppressed, the malfunction of the transistor can be eliminated, and the gate vibration when a large current is applied can be eliminated.

According to a second aspect of the present invention, in the power converter according to the first aspect, one arm is composed of a plurality of structural units with two sets of unit arm elements connected in parallel as a structural unit, and gate driving is performed. It is characterized in that the resistance on the unit arm element side of the T-type resistance circuit provided at the output end of the circuit is provided as a damping resistance for each structural unit. According to the present invention, it is possible to prevent overlapping of vibrations due to the connection of two parallel connections, and prevent malfunction of the transistor at the output end for gate drive.

According to a third aspect of the present invention, in the power converter according to the first aspect, the resistance on the unit arm element side of the T-type resistance circuit provided at the output end of the gate drive circuit is used as a damping resistance for each unit arm element. It is characterized by being provided in. According to this invention, the vibration suppression is made more effective,
It is possible to prevent malfunction of the gate drive circuit.

According to a fourth aspect of the present invention, in the power converter according to the second aspect, each structural unit is structurally unitized for each structural unit, including a connecting conductor to each unit arm element, and damping is performed. It is characterized in that a resistor is provided for each structural unit. According to the present invention, it is possible to reduce the influence of other unit arm elements and prevent malfunction of the gate drive circuit.

The invention according to claim 5 relates to claims 1 to 4.
In the power converter according to any one of the items 1 to 3, in addition to the T-type resistance circuit, a damping resistor is connected to the gate drive circuit side of the return side gate signal line. According to the present invention, with respect to energization / interruption of a large current, the vibration of the gate line on the switching element emitter side is also damped at the output end on the gate drive circuit side, thereby reducing the vibration from the emitter side line and reducing the gate drive circuit. It is possible to prevent malfunction of the output end transistor and prevent damage to the unit arm element.

According to a sixth aspect of the present invention, in the power converter according to the first aspect, one arm is composed of an odd number of unit arm elements connected in parallel, and is provided at the output end of the gate drive circuit. A resistance on the unit arm element side of the resistance circuit is a first damping resistance provided for every two sets of unit arm elements connected in parallel, and a second damping resistance provided for a single unit arm element. And the ratio of the resistance value R21 of the first damping resistor to the resistance value R22 of the second damping resistor is approximately 2 · R21 = R22. According to the present invention, when one arm is composed of an odd number of unit arm elements, it is divided into two parallel connection constitutional units and one constitutional unit, whereby two parallel connection of the switching elements of the parallel connection constitution is achieved. The current does not easily flow to the gate of the switching element on the side, the switching loss does not increase, and the loss can be balanced to achieve the same condition by balancing the one parallel connection side.

The invention according to claim 7 relates to claims 1 to 6.
In the power converter according to any one of the items 1 to 10, a noise absorbing circuit for a pair of signal lines for each unit arm element for individually supplying a gate signal to the unit arm element is provided at the output end of the gate drive circuit. The feature is that a ferrite core is inserted. According to the present invention, it is possible to improve noise immunity against vibrations in the common mode with respect to vibrations on the emitter side of the arm element, and thereby suppress vibrations that propagate to the gate drive circuit side.

The invention according to claim 8 relates to claims 1 to 7.
In the power converter according to any one of items 1 to 3, the gate drive circuit includes a pair of complementary transistors connected in series in order to supply an ON / OFF gate signal to each unit arm element, and an electrode on the common connection side of each transistor. It is characterized by inserting an amorphous core for noise absorption into each terminal. According to the present invention, it is possible to reduce noise flowing to the emitter of a transistor, prevent noise from propagating from the stray capacitance between the emitter and the base to the base side, and prevent the transistor from malfunctioning due to the noise being amplified again. it can.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

<Embodiment 1> FIG. 1 shows an essential part of an embodiment of the invention according to claim 1 and an essential part of its control device.

FIG. 1 shows an inverter 4 constituting a power converter and a control device portion for the same. Although the inverter 4 is of a three-phase type (see FIG. 10), only the U-phase arms 4UP and 4UN are shown here as a representative, and the positive and negative arms each have two parallel unit arm elements 4U.
It is constituted by P1, 4UP2 and 4UN1, 4UN2. Positive side unit arm element 4UP of the inverter 4
1, 4UP2 and negative side unit arm elements 4UN1, 4U
N2 is connected to the unit arm elements of the other phase via the DC buses P and N on the DC side, connected to the DC sides of the smoothing capacitor 3 and the converter 2, and connected to the AC motor 5 on the AC side.

The gate of the switching element included in each unit arm element is a gate resistance Rgp connected in series.
It is connected to the output end of the gate drive circuit 12 via 1, Rgp2, Rgn1, Rgn2 and a connecting wire. In the gate drive circuit 12, the negative unit arm element 4UN
Only the drive circuit for 1,4 UN2 is shown in detail. Although a detailed circuit is not shown for the positive side unit arm elements 4UP1 and 4UP2, a drive circuit having the same circuit configuration is provided although it is insulated from the negative side circuit. The wiring from the gates of the unit switching elements connected in parallel in two to the drive circuit board 12 is collected for each group of switching elements connected in parallel.
Be led to.

In the gate drive circuit 12, the input of the resistor R3 connected between the common connection point of the series-connected complementary transistors Tr1 and Tr2 and the reference potential line 14 derived from the midpoint of the gate signal power supply 11. The damping resistors R1 and R2 are connected in series on the output side and the output side,
The gate wiring is led out from the output side of the damping resistor R2. As a result, the three resistors R1, R2 and R3 form a T-shaped circuit. The collector of the transistor Tr1 is connected to, for example, the + 15V terminal of the gate signal power supply 11, the collector of the transistor Tr2 is connected to the −15V terminal of the power supply 11, and the reference potential line 14 is at the midpoint of the power supply 11, that is, 0V.
It is derived from the potential point. Thus, in response to the positive or negative control signal from the upper control means, the gate control means 10 outputs a positive or negative gate control signal, whereby the resistance R
3, through transistor Tr1 + 15V (when on)
PWM control signal is generated or transistor Tr
A -15V (when off) rectangular wave PWM control signal is generated via 2 and applied as a gate control voltage to the switching elements of the unit arm elements 4UN1 and 4UN2 via the gate resistors Rgn1 and Rgn2.

According to the circuit configuration of FIG. 1, when the negative side vibration of the switching element generated during the OFF operation at the time of the current reduction at the time of the PWM control switching at the time of energizing a large current is propagated from the switching element to the gate drive circuit 12. Vibrations from the gates of the respective parallel-connected elements are damped by the damping resistors R1 and R2, and the transistors Tr1 and Tr2
Vibration can be prevented and further vibration due to malfunction of the transistors Trl and Tr2 can be suppressed. Further, on the side of the resistor R1, the overvoltage protection means ZD can suppress the excessive vibration mixed therein.

In the short-circuit protection operation, after the short-circuit detection means 13 detects the short-circuit current, a very large short-circuit current flows because all the arms of all phases of the inverter 4 are once turned on, and then the gate voltage is reduced. Although the operation of narrowing the short-circuit current is performed, the vibration from the switching element can be suppressed in that case as well.

<Second Embodiment> Next, the second embodiment of the present invention will be described with reference to FIG. FIG. 2 shows a circuit configuration for one phase of the inverter 4.

U-phase arms 4UP and 4UN are respectively constituted by four positive side unit arm elements 4UP1 to 4UP4 and negative side unit arm elements 4UN1 to 4UN4. The positive side of the unit arm element on the positive side is connected to the inverter arm of another phase and the DC terminal of the converter 2 via the positive side bus P and the negative side of the unit arm element on the negative side is connected to the negative side bus N, respectively. To be done.

The gate drive circuit 12 is connected to the gates of the respective switching elements via gate resistors Rgp1 to Rgp4 and Rgn1 to Rgn4, respectively.

The characteristics of the gate drive circuit 12 shown in FIG.
This is because each of the four unit arm elements forming the arms 4UP and 4UN is put together into a unit, and the common damping resistors R2a and R2b are arranged in each unit. Other configurations are similar to those of the first embodiment.

According to this embodiment, when a large current is applied or a short circuit protection operation is performed, the gate connection lines of the unit arm elements are combined on the drive circuit side in units of two parallel connections, and the two parallel connections are temporarily dumped. After that, the gates of the other parallel connection components are connected together, and a damping resistor is placed between the connection and the output of the drive circuit to prevent the vibration from overlapping due to the connection of the two parallel connections. Prevent and prevent gate drive transistors Tr1 and Tr
2 can be prevented. Further, by dividing every two parallel connections, the current flowing into the gate of the unit arm element can be configured without being reduced as compared with the first embodiment, so that the switching loss of the unit arm element is increased in the parallel connection configuration. The gate vibration can be suppressed without increasing it.

<Third Embodiment> Next, the third embodiment of the present invention will be described with reference to FIG.

The circuit of FIG. 3 shows one phase (U phase) of the inverter 4 in which each phase arm is composed of two parallel unit arm elements. If only the negative side is described here, the gate of each unit arm element is introduced into the gate drive circuit 12 via each gate resistance Rgn1 and Rgn2, and inside the gate drive circuit 12, each switching element is connected via each damping element R21 and R22. Connected to the resistor R3.

In the present embodiment, by disposing a damping resistor for each element, the resistance value between adjacent parallel connection configurations becomes higher than usual, so that vibration suppression in the parallel connection configuration is effective. Can be suppressed. Further, the current flowing into the gate of each unit arm element during driving can be made larger than that which is commonly inserted in a plurality of parallel connection configurations, and the loss due to switching can be reduced.

<Embodiment 4> Next, an embodiment of the invention according to claim 4 will be described with reference to FIGS.
FIG. 4 is a circuit configuration diagram for one phase of the inverter, and FIG.
FIG. 3 is a stack configuration diagram of a total of 2 units and 4 parallel connections configured by parallelizing one unit.

The electrical circuit configuration is similar to that of FIG. In this embodiment, as shown in FIG. 5, four parallel configurations are used in which unit arm elements 4UP1, 4UP2, 4UN1, 4 are provided.
UN2, unit capacitors 3A and 3B, and a first unit including a first connecting conductor group, and unit arm element 4U
P3, 4UP4, 4UN3, 4UN4, unit capacitors 3C and 3D, and a second unit including a second connection conductor group. The first connecting conductor group includes, in addition to the connecting conductors 7A, 7B, 7E, 7F, 7I, 8A already described, a positive side connecting plate P4 near the positive electrode of the unit capacitor 3A, and a negative side connecting plate N4 as a unit. It is provided near the negative electrode of the capacitor 3B. The positive side connecting plate P4 is connected to the positive electrode of the unit capacitor 3A and the connecting conductor 7I. The connection conductor 7I may be the connection plate P in some cases.
4 may be integrally configured. The negative side connecting plate N4 is connected to the connecting conductor 7F by a connecting conductor (not shown).
The second connection conductor group includes the connection conductors 7C, 7D,
In addition to 7G, 7H, 7J and 8B, a positive side connecting plate P5 is provided near the positive electrode of the unit capacitor 3C, and a negative side connecting plate N5 is also provided.
Is provided near the negative electrode of the unit capacitor 3D. The positive side connecting plate P5 is connected to the positive electrode of the unit capacitor 3C and the connecting conductor 7J. In addition, connection conductor 7J
May be integrally formed with the connecting plate P5 in some cases. The negative side connecting plate N5 is connected to the connecting conductor 7H by a connecting conductor (not shown).

The positive side connecting plates P4 and P5 are connected to the positive side bus P1 via the connecting conductors 21P and 22P, respectively, and the negative side connecting plates N4 and N5 are connected to the negative side bus N1 via the connecting conductors 21N and 22N, respectively. Connected.

The gate terminals G of the unit switching elements included in each unitized 4-parallel connection arm are connected to the gate drive circuit 12 via a gate line.
The gate lines of each two-parallel connection configuration are combined at the drive circuit input section, and the first two-parallel connection configuration section includes the damping resistor R2.
a, and the second 2-parallel connection component is connected to the driving transistors Tr1 and T1 via the damping resistor R2b.
It is connected to the gate drive circuit 12 including r2. Other configurations are the same as those in the first embodiment.

This embodiment corresponds to a development of the embodiment shown in FIG. 2, and each parallel connection structure is made into two parallel connection one unit, so that the unit of the other parallel connection structure of the emitter line of the main circuit portion is formed. It is possible to reduce the influence from the arm element.

<Embodiment 5> Claim 5 with reference to FIG.
Embodiments of the present invention will be described. Here, the circuit configuration of FIG. 1 is basically used, and the description of the same functional units is omitted.

The circuit of FIG. 6 is characterized in that, in addition to the damping resistor R2 inserted at the collector line side output end of the unit arm element of the drive circuit 12, a damping resistor R4 is also provided at the emitter line side output end. is there.

By connecting the damping resistors to both sides in this way, the vibration of the emitter line of the unit arm element having the parallel connection configuration is transmitted through the gate protection Zener diode ZD on the side of the drive circuit 12 to the drive transistor T.
By suppressing the inflow of the vibrations to the emitters of r1 and Tr2, it is possible to suppress the vibration of the gate signal due to the malfunction of the transistors TRl and Tr2 and prevent the unit arm elements from being damaged.

<Embodiment 6> Next, an embodiment of the invention according to claim 6 will be described with reference to FIG.

In this embodiment, a case will be described in which three parallel connection configurations are assumed as a power conversion device equipped with an inverter and / or converter in which an odd number of unit arm elements are connected in parallel. First and second two
A common damping resistor R21 is used for the gates of the switching elements of the two arm elements 4UN1 and 4UN2,
Damping resistance R2 for the third arm element 4UN3
2 is used. In this case, the damping resistor R21 is temporarily set to 1
When it is set to Ω, the damping resistance R22 is set to 2Ω which is twice that. That is, 2 · R21 = R22. By doing so, the gate resistance of each switching element in the inverter 4 is the same, that is, Rgn1 = Rgn2 = Rg.
Assuming that it is n3, the currents supplied to the respective gates by the drive transistors Tr1 and Tr2 have the same value.

As a result, the gate current can be made to flow evenly through each gate of the unit arm elements on the two parallel connection sides of the unit arm elements of the parallel connection configuration while saving the damping resistance, and the loss due to switching can be balanced in each parallel. The connection can be made between the unit arm elements.

<Embodiment 7> Next, an embodiment of the invention according to claim 7 will be described with reference to FIG.

This embodiment is basically the same as the embodiment of FIG. 2, but here the gate drive circuit 12 is connected to the gate of the unit arm element at the gate drive circuit output end portion of the signal line. , Unit arm elements 4UN1 to 4UN
4 and 4UP1 to 4UP4 noise absorbing ferrite cores L1 to L4 and L5 for each pair of reciprocating signal lines
It is characterized by the insertion of L8.

By doing so, it is possible to improve the noise resistance against the vibration in the common mode with respect to the vibration on the emitter side of each unit arm element, and thereby suppress the vibration that propagates to the gate drive circuit side. it can.

<Embodiment 8> Next, an embodiment of the invention according to claim 8 will be described with reference to FIG.

This embodiment is similar to the device of FIG.
The present invention is intended for a power converter having two parallel connection configurations in which one arm is composed of two sets of unit arm elements, and a noise absorbing amorphous core L9 is inserted into each emitter terminal of the gate driving transistors Tr1 and Tr2. It is characterized by that.

According to this embodiment, when noise due to vibration of the unit arm element or switching between the gate of the unit arm element and the drive circuit 12 is superimposed on the gate signal line, the noise is generated by the transistor Tr1. , Tr
It is possible to reduce the propagation of noise and vibration to the base side of the transistors Tr1 and Tr2 by propelling them by the core L9 before they propagate to the emitter terminal of No. 2 and to prevent their malfunction.

<Other Embodiments> Although the embodiments described above relate to an inverter, the present invention can be applied to a controllable converter in the same manner to achieve the same operation and effect.

[0057]

According to the present invention, the arm element may be damaged due to the oscillation state of the gate signal at the time of switching when a large current is applied or the gate vibration at the time of gate voltage throttling during the short-circuit protection operation. Therefore, it is possible to suppress them, and thereby stable large-current conduction and stable short-circuit protection operation can be performed.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram of a main part of a power conversion device according to a first embodiment of the present invention.

FIG. 2 is a circuit configuration diagram of a main part of a power conversion device according to a second embodiment of the present invention.

FIG. 3 is a circuit configuration diagram of a main part of a power conversion device according to a third embodiment of the present invention.

FIG. 4 is a circuit configuration diagram of a main part of a power conversion device according to a fourth embodiment of the present invention.

5 is a plan view showing the stack structure in FIG. 4. FIG.

FIG. 6 is a circuit configuration diagram of a main part of a power conversion device according to a fifth embodiment of the present invention.

FIG. 7 is a circuit configuration diagram of a main part of a power conversion device according to a sixth embodiment of the present invention.

FIG. 8 is a circuit configuration diagram of a main part of a power conversion device according to a seventh embodiment of the present invention.

FIG. 9 is a circuit configuration diagram of a main part of a power conversion device according to an eighth embodiment of the present invention.

FIG. 10 is a circuit wiring diagram of a known power conversion device.

FIG. 11 is a circuit diagram of the converter arm shown in FIG.
The connection diagram showing the example constituted from parallel unit capacitors.

FIG. 12 is a circuit diagram of the smoothing capacitor shown in FIG. 10, which includes two series and two parallel unit capacitors and four inverter arms.
FIG. 4 is a connection diagram showing an example of configuration of parallel unit arm elements.

FIG. 13 is a plan view showing a stack configuration of a conventional power conversion device.

14 is a side view of the stack structure shown in FIG. 11. FIG.

FIG. 15 is an external front view of a conventional power conversion device.

FIG. 16 is a block diagram of a conventional gate drive circuit.

FIG. 17 is a gate vibration waveform diagram during the conventional short-circuit protection operation.

[Explanation of symbols]

1 3 Phase AC Power Supply 2 Converter 3 Smoothing Capacitor 3A, 3B, 3C, 3D Unit Capacitor 4 Inverter 4UP, 4UN U Phase Arm 4UP1 to 4UP4, 4UN1 to 4UN4 Unit Arm Element 5 AC Motor 8 Cooling Body 10 Gate Control Means 11 Gate Signal Power supply 12 Gate drive circuit board 13 Short circuit detection means Tr1, Tr2 Gate drive transistors R2, R2a, R2b, R21, R22, R4 Damping resistance

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 5H006 AA05 BB05 CA01 CA13 CB01                       CB08 FA02 HA81 HA84                 5H007 AA01 BB06 CA01 CB02 CB05                       CC07 DB03 DC02 EA02 FA03                       FA13 HA07                 5H740 AA04 BA11 BB02 BB05 BB10                       KK01 MM11 NN01 PP02 PP03

Claims (8)

[Claims] 1. A power converter comprising a plurality of gate-controlled unit arm elements connected in parallel to one arm, and a gate drive circuit for supplying an ON / OFF gate signal to each unit arm element. A T-type resistance circuit formed by connecting three resistors in a T-shape is arranged at the output end of the gate drive circuit, and a gate line from the output end to each unit arm element is branched, and the branched gate line A power conversion device characterized in that a gate signal transmitted via the unit arm element is supplied to a gate of each unit arm element via a gate resistor arranged for each unit arm element. 2. The power converter according to claim 1, wherein one arm is composed of a plurality of structural units with two sets of unit arm elements connected in parallel as a structural unit, and is provided at an output end of the gate drive circuit. A power converter, wherein a resistance on the unit arm element side of the T-type resistance circuit provided is provided as a damping resistance for each of the constituent units. 3. The power converter according to claim 1, wherein a resistance on the unit arm element side of the T-type resistance circuit provided at the output end of the gate drive circuit is provided as a damping resistance for each unit arm element. A characteristic power conversion device. 4. The power converter according to claim 2, wherein each structural unit is structurally unitized for each structural unit, including a connection conductor to each unit arm element, and the damping resistance is set to each unit. An electric power converter provided for each structural unit. 5. The power converter according to claim 1, further comprising a damping resistor connected to the gate drive circuit side of the return side gate signal line in addition to the T-type resistor circuit. A power converter characterized by the above. 6. The power converter according to claim 1, wherein one arm is composed of an odd number of unit arm elements connected in parallel, and a unit of a T-type resistance circuit provided at an output end of the gate drive circuit. The resistance on the arm element side includes a first damping resistance provided for each of two sets of unit arm elements connected in parallel, and a second damping resistance provided for a single unit arm element. The resistance value R21 of the first damping resistor and the resistance value R22 of the second damping resistor
The power conversion device is characterized in that the ratio of R and R is approximately 2 · R21 = R22. 7. The power conversion device according to claim 1, wherein each unit arm element for individually supplying a gate signal to the unit arm element is provided at an output end of the gate drive circuit. A power converter, wherein a ferrite core for absorbing noise is inserted in each of a pair of signal lines. 8. The power conversion device according to claim 1, wherein the gate driving circuit supplies a pair of complementary complementary gates for supplying an ON / OFF gate signal to each of the unit arm elements. A power conversion device comprising a transistor, wherein an amorphous core for noise absorption is inserted in each electrode terminal of a common connection side of each transistor.