JP2006271041A - Voltage-driven semiconductor device gate drive device - Google Patents

Abstract

To reduce the size and cost of an apparatus by reducing the volume of an insulating transformer and omitting a transmission circuit such as an optical fiber cable.
A modulation circuit 26 superimposes power obtained by converting direct current into high frequency alternating current in a direct current / alternating current circuit 13 and a gate signal from an interface circuit 27, and an insulation transformer 18 from the insulation transformer 21 is connected to the nth stage. By sequentially transmitting to the driving circuits 25 to 22 through the insulating transformer, the withstand voltage of the insulating transformer is lowered, the volume is reduced, and the optical fiber cable and the like can be omitted.
[Selection] Figure 1

Description

  The present invention relates to a power conversion device in which a plurality of voltage-driven semiconductor elements such as IGBTs (insulated gate bipolar transistors) are connected in series per arm, and more particularly to a gate drive device.

FIG. 5 shows a circuit example of a general power converter (inverter) in which a plurality of voltage-driven semiconductor elements such as IGBTs are connected in series to each arm.
In FIG. 5, 28 is a three-phase AC input power supply, 29 is a rectifier circuit, 30 is a smoothing capacitor, 31 to 36 are a plurality of voltage-driven semiconductor elements connected in series, and 37 is a motor load. Since the gate drive circuit GDU of each voltage-driven semiconductor element operates at a different reference potential, it is necessary to secure insulation for each gate drive circuit GDU and supply a gate signal and power to each gate drive circuit GDU. .

FIG. 6 shows an example in which four IGBTs are connected in series as a voltage-driven semiconductor element in the gate driving device disclosed in Patent Document 1, for example.
In FIG. 6, 1 to 4 are IGBTs in which diodes are connected in antiparallel, 5 to 8 are drive circuits, 9 to 12 are insulation transformers, 13 is a DC / AC (DC / AC) conversion circuit, and 14 is a DC power supply. . That is, drive circuits 5 to 8 are connected to the IGBTs 1 to 4, and an optical fiber cable for transmitting a gate signal is connected to signal inputs of the drive circuits 5 to 8. A DC power source 14 is connected to the primary side of the insulating transformers 9 to 12 via the DC / AC conversion circuit 13, and the secondary side of the insulating transformers 9 to 12 is connected to each power input of the drive circuits 5 to 8. Yes.

The operation of FIG. 6 will be described.
Since gate signals (ON signal and OFF signal) from a control device (not shown) are transmitted to the respective drive circuits 5 to 8 by optical fiber cables, the gate signals are transmitted in an insulated manner. When power is supplied from the DC power supply 14, it is converted into AC power by the DC / AC conversion circuit 13, and power is supplied to the drive circuits 5 to 8 through the insulating transformers 9 to 12. In this way, power is supplied while ensuring insulation for each drive circuit.
Japanese Patent Application Laid-Open No. 10-164843

  As described above, power can be supplied to each gate drive circuit while ensuring insulation for each drive circuit. However, for example, if the ground potential on the primary side of the insulating transformer 12 is 0 [V] and the ground potential on the secondary side is also 0 [V], the collector-emitter voltages of the IGBTs 1 to 4 are set to VCE [ V], the ground potential on the primary side of the insulating transformer 9 is 3 VCE [V]. For this reason, since the withstand voltage required for the insulating transformer 9 is increased, the volume of the insulating transformer is increased.

Further, since the gate signal is transmitted for each driving circuit, a circuit for converting the optical signal into an electric signal is required for each driving circuit, and the board area is increased, and furthermore, the number of optical fiber cables is required in series. Therefore, the cost increases. As described above, particularly in a high-voltage and large-capacity power conversion device in which a plurality of voltage-driven semiconductor elements are connected in series, there is a problem that the device is increased in size and cost.
Accordingly, an object of the present invention is to reduce the insulation withstand voltage required for the insulating transformer to reduce the size and cost.

  In order to solve such a problem, the invention according to claim 1 can simultaneously transmit a gate signal and power to each of the voltage-driven semiconductor elements connected in series to each arm (an integer of 2 or more). An isolation transformer circuit, a demodulation circuit that separates the gate signal and power transmitted from the isolation transformer circuit, and a drive circuit that drives the voltage-driven semiconductor element based on the gate signal. A modulation circuit that combines a gate signal and power is connected to the primary side of the isolation transformer circuit, an interface circuit that receives a signal from the control device is connected to the signal input of the modulation circuit, and a DC is connected to the power input of the modulation circuit A DC power supply is connected via an AC conversion circuit, the primary side of the second-stage isolation transformer circuit is connected to the secondary side of the first-stage isolation transformer circuit, and so on. In wherein the connection.

  According to the second aspect of the present invention, an insulating transformer circuit capable of simultaneously transmitting a gate signal and power to each of n (an integer of 2 or more) voltage-driven semiconductor elements connected in series to each arm, and the insulating transformer A demodulating circuit for separating a gate signal and power transmitted from the circuit, and a driving circuit for driving a voltage-driven semiconductor element based on the gate signal, and a gate on the primary side of the n-th isolation transformer circuit A modulation circuit that synthesizes the signal and power is connected, an interface circuit that receives a signal from the control device is connected to a signal input of the modulation circuit, and a DC power supply is connected to the power supply input of the modulation circuit via a DC / AC conversion circuit And the primary side of the (n-1) th stage isolation transformer circuit is connected to the secondary side of the nth stage isolation transformer circuit, and so on up to the first stage. .

According to a third aspect of the present invention, there is provided an insulating transformer circuit capable of simultaneously transmitting a gate signal and power to each of n (an integer of 2 or more) voltage-driven semiconductor elements connected in series to each arm, and the insulating transformer. There are provided a demodulating circuit for separating a gate signal and power transmitted from the circuit, and a driving circuit for driving a voltage-driven semiconductor element based on the gate signal, and m (any one of 2 to n-1) stages A modulation circuit that combines the gate signal and power is connected to the primary side of the isolation transformer circuit of the eye, and an interface circuit that receives a signal from the control device is connected to the signal input of the modulation circuit, and the power input of the modulation circuit Connect a DC power supply via a DC / AC converter circuit, connect the primary side of the m + 1 stage isolation transformer circuit to the secondary side of the mth stage isolation transformer circuit, and so on until the nth stage. Connect, and the m secondary side of the step of the insulating transformer circuit connected to the primary side of the isolation transformer circuit m-1 stage, characterized by connecting to the first stop in the same manner.
In any one of the first to third aspects of the invention, a timing adjustment circuit for matching the switching timing can be added to each of the voltage-driven semiconductor elements (the invention of claim 4).

  According to the present invention, in a gate driving device of a power conversion device in which n (an integer greater than or equal to 2) voltage-driven semiconductor elements are connected in series, a gate signal is modulated and superimposed on the gate power converted into high-frequency alternating current, and an insulating transformer Through the first stage drive circuit to the nth stage drive circuit, or from the nth stage drive circuit to the first stage drive circuit, or m (any one of 2 to n-1) stage drive From the circuit to the first stage drive circuit and the nth stage drive circuit, the gate signal and power are simultaneously transmitted in isolation, reducing the volume of the isolation transformer and eliminating the signal transmission circuit such as the optical fiber cable. In particular, it is possible to achieve a reduction in size and cost of a high-voltage, large-capacity power converter.

FIG. 1 is a circuit configuration diagram showing an embodiment of the present invention, which is an example in which four IGBTs are connected in series.
This is configured by adding timing adjusting circuits 15 to 17, demodulating circuits 22 to 25, a modulating circuit 26, an interface circuit 27, and the like to the circuit shown in FIG. Reference numerals 18 to 21 are insulating transformers. As the timing adjustment circuit, a method of adjusting the switching timing using magnetic coupling is used. Such a method is known, for example, from Japanese Patent Application Laid-Open No. 2002-204578.

  That is, the drive circuits 5 to 8 are connected to the IGBTs 1 to 4 via the timing adjustment circuits 15 to 17, respectively, and the gate signal and the power are separated into the signal input and the power input of the drive circuits 5 to 8, respectively. The secondary sides of the insulating transformers 18 to 21 are connected to each other through the demodulation circuits 22 to 25 having the above.

  The output side of the modulation circuit 26 is connected to the primary side of the first-stage isolation transformer 21, and the DC / AC conversion circuit 13 and the DC power supply 14 are sequentially connected to the power supply input of the modulation circuit 26. An interface circuit 27 for receiving a signal from a control device (not shown) is connected to the signal input. As shown in FIG. 1, the primary side of the second-stage insulating transformer 20 is connected to the secondary side of the first-stage insulating transformer 21, and the secondary side of the second-stage insulating transformer 20 is connected to the secondary side. The primary side of the isolation transformer 19 in the stage is connected, and the primary side of the isolation transformer 18 in the fourth stage is connected to the secondary side of the isolation transformer 19 in the third stage.

The operation of FIG. 1 will be described with reference to FIG.
In FIG. 1, when power as shown in FIG. 2B is supplied from the DC power supply 14, the DC / AC conversion circuit 13 converts the power into high-frequency AC power as shown in FIG. Is done. When a gate signal as shown in FIG. 2A is input to the interface circuit 27 from a control device (not shown), the gate signal is input to the modulation circuit 26 via the interface circuit 27. The signal is superimposed on the AC power and output from the modulation circuit 26 as shown in FIG.

  The gate signal is insulated and transmitted to the secondary side of the isolation transformer 21 simultaneously with the power, and is separated into the power as shown in FIG. 2E and the gate signal as shown in FIG. Is transmitted. At the same time, the gate signal superimposed on the high-frequency AC power is transmitted to the primary side of the second-stage isolation transformer 20, and the gate signal and power are simultaneously transmitted to the drive circuit 7 via the demodulation circuit 24 and the isolation transformer 20. Insulated transmission. In this way, the gate signal and the power can be simultaneously insulated and transmitted in sequence from the first stage drive circuit 8 to the fourth stage drive circuit 5. This eliminates the need to individually transmit gate signals to the first to fourth stage drive circuits, so that not only the optical fiber cable can be omitted, but also the substrate area can be reduced. Furthermore, the insulation transformer can be miniaturized by transmitting at a high frequency.

  In FIG. 1, for example, when the ground potential on the primary side of the insulating transformer 21 is 0 [V] and the ground potential on the secondary side is also 0 [V], the respective collector-emitter voltages of the IGBTs 1 to 4 are expressed as VCE. [V], the ground potential on the primary side of the isolation transformer 18 is 2 VCE [V], and the ground potential on the secondary side is 3 VCE [V], which is applied between the primary side and the secondary side of the isolation transformer 18. The potential is VCE [V].

That is, as compared with the one shown in FIG. 6, the insulation withstand voltage required for the insulation transformer can be lowered, so that the insulation transformer can be further reduced.
From the above, the high-voltage, large-capacity power converter is especially large and high-cost by insulating and transmitting the gate signal and power simultaneously from the first-stage drive circuit to the fourth-stage drive circuit by the isolation transformer. Can solve the problem.

FIG. 3 shows another embodiment of the present invention.
The basic configuration is the same as in FIG. 1, but here the gate signal and power are supplied from the fourth-stage insulating transformer 18, and the third-stage insulating transformer 19 is connected to the secondary side of the fourth-stage insulating transformer 18. The primary side is connected, the primary side of the second-stage insulating transformer 20 is connected to the secondary side of the third-stage insulating transformer 19, and the first-stage insulating transformer is connected to the secondary side of the second-stage insulating transformer 20. 21 is different in that the primary side is connected.

As described above, in the circuit of FIG. 3, the gate signal and power are simultaneously insulated and transmitted sequentially from the fourth-stage drive circuit 5 to the first-stage drive circuit 8. The operation is basically the same as that in FIG.
In this manner, the gate signal and power are simultaneously insulated and transmitted one after another from the fourth stage drive circuit to the first stage drive circuit in the same manner as in FIG. Can solve the problem of increasing cost and cost.

FIG. 4 shows still another embodiment of the present invention.
The basic configuration is the same as in FIG. 1 except that the gate signal and power are supplied from the second-stage isolation transformer 20 and the second-stage isolation transformer 20 has a first-stage isolation. The primary side of the transformer 21 and the primary side of the third-stage insulating transformer 19 are connected, and the primary side of the fourth-stage insulating transformer 18 is connected to the secondary side of the third-stage insulating transformer 19. It is different.
As described above, in FIG. 4, the gate signal and the power are simultaneously insulated and transmitted sequentially from the second-stage drive circuit 7 to the first-stage drive circuit 8 and the fourth-stage drive circuit 5 in sequence. Since it is basically the same as 1, the details are omitted.

In this way, the gate signal and the power are isolated and transmitted in sequence by the isolation transformer from the second stage drive circuit to the first and fourth stage drive circuits in the same manner as in FIG. It is possible to solve the problem that the conversion device is increased in size and cost.
In the above description, the lowermost voltage-driven semiconductor element is described as the first stage, and the uppermost voltage-driven semiconductor element is described as the nth stage. However, the uppermost voltage-driven semiconductor element is described as the first stage and the lowermost stage. The present invention can also be applied in the same manner even if the voltage-driven semiconductor element is n-th stage.

  Further, the example in which the amplitude of the gate signal is modulated has been described above. However, other modulation schemes such as frequency modulation can be applied, and even when the timing adjustment circuit is not used, the same can be applied. .

Circuit configuration diagram showing an embodiment of the present invention Waveform diagram of each part for explaining the operation of FIG. Circuit configuration diagram showing another embodiment of the present invention The circuit block diagram which shows other embodiment of this invention Circuit diagram showing a general example of a power converter Circuit configuration diagram showing a conventional example of a gate driving device

Explanation of symbols

DESCRIPTION OF SYMBOLS 1-4 (Q1-Q4) ... IGBT (insulated gate bipolar transistor), 5-8 ... Gate drive circuit, 13 ... DC / AC (direct current / alternating current) conversion circuit, 14 ... DC power supply, 16-17 ... Timing adjustment circuit , 18 to 21 ... insulating transformers, 22 to 25 ... demodulation circuits, 26 ... modulation circuits, 27 ... interface circuits.

Claims (4)

  An isolation transformer circuit capable of transmitting a gate signal and power simultaneously to each of n (an integer of 2 or more) voltage-driven semiconductor elements connected in series to each arm, and a gate signal transmitted from the isolation transformer circuit And a demodulating circuit for separating the power and a driving circuit for driving the voltage-driven semiconductor element based on the gate signal, and the gate signal and the power are synthesized on the primary side of the first-stage insulating transformer circuit A modulation circuit is connected, an interface circuit that receives a signal from the control device is connected to a signal input of the modulation circuit, a DC power supply is connected to a power supply input of the modulation circuit via a DC / AC conversion circuit, and the one stage A voltage-driven semiconductor device comprising: a secondary side of a second isolation transformer circuit connected to a secondary side of the second isolation transformer circuit; Over door drive.   An isolation transformer circuit capable of transmitting a gate signal and power simultaneously to each of n (an integer of 2 or more) voltage-driven semiconductor elements connected in series to each arm, and a gate signal transmitted from the isolation transformer circuit And a demodulating circuit for separating power and power and a driving circuit for driving a voltage-driven semiconductor element based on the gate signal, and the gate signal and power are synthesized on the primary side of the n-th isolation transformer circuit A modulation circuit is connected, an interface circuit that receives a signal from the control device is connected to a signal input of the modulation circuit, a DC power supply is connected to a power supply input of the modulation circuit via a DC / AC conversion circuit, and the n stages A voltage-driven semiconductor device comprising: a primary side of an n-1 stage isolation transformer circuit is connected to a secondary side of an eye isolation transformer circuit; Gate drive of.   An isolation transformer circuit capable of transmitting a gate signal and power simultaneously to each of n (an integer of 2 or more) voltage-driven semiconductor elements connected in series to each arm, and a gate signal transmitted from the isolation transformer circuit And a demodulating circuit for separating power and a driving circuit for driving a voltage-driven semiconductor element based on the gate signal, and a primary of an insulating transformer circuit in the m (any one of 2 to n-1) stage A modulation circuit that combines a gate signal and power is connected to the side, an interface circuit that receives a signal from the control device is connected to a signal input of the modulation circuit, and a DC / AC conversion circuit is connected to the power supply input of the modulation circuit A DC power supply, connect the primary side of the m + 1 stage isolation transformer circuit to the secondary side of the mth stage isolation transformer circuit, connect to the nth stage in the same manner, and A gate drive of a voltage-driven semiconductor device, characterized in that the primary side of the m-1 stage isolation transformer circuit is connected to the secondary side of the isolation transformer circuit of the stage, and so on up to the first stage. apparatus. 4. The gate drive device for a voltage driven semiconductor element according to claim 1, wherein a timing adjustment circuit for matching a switching timing is added to each of the voltage driven semiconductor elements.

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