JP3561469B2 - Semiconductor switch circuit for high voltage - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a high-voltage semiconductor switch circuit for switching a high voltage by connecting a plurality of semiconductor switches in series, and more particularly to using a conductor instead of an optical cable to transmit a control signal for driving each semiconductor switch. The present invention relates to a high-voltage semiconductor switch circuit that is enabled.
[0002]
[Prior art]
FIG. 2 is a configuration diagram showing a conventional high-voltage semiconductor switch circuit. In FIG. 2, reference numerals 1a, 1b, and 1c denote semiconductor switches, three of which are connected in series. Note that 1a is connected to the low voltage section and 1c is connected to the high voltage section. Numerals 2a, 2b, 2c denote snubber circuits which suppress a surge voltage applied to both ends of the semiconductor switch and lower a voltage rising rate and a current rising rate. Each of the snubber circuits 2a, 2b, 2c is connected in parallel to each of the semiconductor switches 1a, 1b, 1c, with the return side being common. The snubber circuits 2a, 2b, and 2c are obtained by adding a power supply circuit including a zener diode Z and a capacitor C1 to the basic form of an RC snubber circuit including a diode D, a resistor R, and a capacitor C1. The one including is called a snubber circuit. This power supply circuit is used as a power supply for switch drive circuits 3a, 3b, 3c to be described later.
[0003]
Reference numerals 3a, 3b, and 3c denote switch drive circuits, which are provided in the semiconductor switches 1a, 1b, and 1c, respectively, and include opto-electric signal converters 4a, 4b, and 4c and drive circuits 11a, 11b, and 11c. The drive circuits 11a, 11b, and 11c are circuits that amplify the output signals of the optical-electrical signal converters 4a, 4b, and 4c so that the switches can be driven. The optical-to-electrical signal converters 4a, 4b, 4c and the drive circuits 11a, 11b, 11c are connected such that the reference of the drive power supply is the return-side potential of each of the switches 1a, 1b, 1c. Have been. That is, the optical-electrical signal converters 4a, 4b, 4c and the drive circuits 11a, 11b, 11c are connected so that the semiconductor switch and the snubber circuit and the return circuit are common, and the power supply from each snubber circuit. Is supplied. Reference numeral 5 denotes an optical fiber, and reference numeral 6 denotes an electro-optical converter for a switch ON / OFF control signal.
[0004]
Each semiconductor switch is connected in series in three stages, with the semiconductor switch 1a connected to the low-voltage part as the first stage, and a semiconductor switch series-connected body in which the third stage in the last stage is connected to the high-voltage part. Can be said. Also, three stages of snubber circuits are provided, and three stages of optical-electrical signal converters and drive circuits are also provided. The number of stages is not limited to three, and may be n (n is a positive integer of 2 or more).
[0005]
Next, the operation will be described. In the electro-optical conversion circuit 6, the electro-optical converters 6a, 6b, and 6c are connected in series by the number corresponding to the number of semiconductor switches, and are simultaneously controlled by an ON / OFF control signal (trigger signal) input from the input terminal 61. Performs electrical-optical conversion. The optical signal is transmitted to each stage by the optical fiber 5. At each stage, the received optical signal is converted into an electrical signal by the optical-electrical signal converters 4a, 4b, 4c and output to the drive circuits 11a, 11b, 11c. The drive circuits 11a, 11b, and 11c amplify the electric signals and output the amplified signals to the semiconductor switches 1a, 1b, and 1c. The semiconductor switches 1a, 1b, 1c perform a switching operation based on the amplified ON / OFF control signal.
[0006]
[Problems to be solved by the invention]
The conventional high-voltage semiconductor switch circuit is configured as described above, and the optical cable has a minimum bending radius. Therefore, it is necessary to bend the optical cable at a larger bending radius. Therefore, the bending radius of the optical cable increases. In addition, there is a problem that the optical cable needs to be fixed to an insulator, so that the apparatus scale is increased and the cost is increased.
[0007]
SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems. An n-stage semiconductor switch is connected in series with a semiconductor switch connected to a low-voltage section as a first stage, and a high-voltage semiconductor switch is connected to a final stage. And a photocoupler for transmitting the ON / OFF control signal of the semiconductor switch of each stage, and the ON / OFF control signal of the nth stage is connected to the (n-1) th stage. It is configured to be transmitted based on the output signal of the photocoupler, and the delay time generated in the photocoupler is adjusted by a timing adjustment circuit so that each semiconductor switch is turned on / off at the same time. An object is to provide a high-voltage semiconductor switch circuit that can omit an electric-optical conversion circuit for performing optical conversion and an optical cable.
[0008]
[Means for Solving the Problems]
In the high-voltage semiconductor switch circuit according to the present invention, the semiconductor switches connected to the low-voltage section are the first stage, and the semiconductor switches are connected in n stages (n is a positive integer of 2 or more) in series. A semiconductor switch series-connected body connected to the voltage unit,
An n-stage drive circuit connected to each of the n-stage semiconductor switches and outputting a drive signal to the semiconductor switch;
An ON / OFF control signal of each of the n-stage semiconductor switches is input, an ON / OFF control signal transmitted by light is output as an electric signal, and the light-emitting element of the n-th stage photocoupler is n−1 An n-stage photocoupler connected to the output circuit of the (n-1) th photocoupler so as to be driven based on an ON / OFF control signal output from the output circuit of the photocoupler of the stage;
The timing of the ON / OFF control signal output from the n-th stage photocoupler being sequentially delayed with respect to the (n-1) th stage is adjusted so that all the semiconductor switches are simultaneously turned ON / OFF, An n-stage timing adjustment circuit configured to input the adjusted ON / OFF control signal to the drive circuit of each stage;
A trigger circuit for inputting an ON / OFF control signal to the light emitting element of the photocoupler in the first stage.
[0009]
Further, the timing adjustment circuit is configured so that the ON control signal and the OFF control signal can be adjusted separately.
Further, each semiconductor switch of the semiconductor switch series connection body is provided with an n-stage snubber circuit connected in parallel so that a return circuit becomes common to suppress surge voltage, and the snubber circuit includes a zener diode and a capacitor on the return side. A power supply circuit composed of a parallel connection body is added, and the output circuit of each stage of the photocoupler and the drive circuit of each stage are connected so that the semiconductor switch and the snubber circuit of each stage and the return circuit are common. At the same time, power is supplied from the snubber circuit of each stage.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiment 1 FIG.
FIG. 1 is a configuration diagram showing Embodiment 1 of the present invention. In FIG. 1, portions denoted by the same reference numerals as those in FIG. 2 indicate the same or corresponding portions, and description thereof will be omitted.
Reference numerals 3a, 3b, and 3c denote switch drive circuits. In the first embodiment, each switch drive circuit includes a photocoupler and a timing adjustment circuit described later and a drive circuit similar to that in FIG. 7a, 7b, 7c are photocouplers, 71, 72, 73 are light emitting elements of the photocouplers 7a, 7b, 7c, and in FIG. 1 are light emitting diodes. Reference numerals 74, 75 and 76 denote output circuits of the photocouplers 7a, 7b and 7c, each comprising, for example, a phototransistor.
[0011]
Reference numerals 8a, 8b, and 8c denote timing adjustment circuits for matching the timings of the ON / OFF control signals of the respective stages, and each has an adjustment function for ON and OFF control signals. A trigger circuit 9 outputs an ON / OFF control signal to the light emitting diode of the first stage photocoupler.
The output terminal of the output circuit 74 of the first-stage photocoupler is connected to the cathode of the light emitting diode 72 of the second-stage photocoupler, and the power supply for the output circuit 74 of the first-stage photocoupler is a current limiting resistor R2. It is connected to the anode of the light-emitting diode 72 of the second-stage photocoupler via the second stage. Similarly, the output terminal of the output circuit 75 of the second-stage photocoupler is connected to the cathode of the light emitting diode 73 of the third-stage photocoupler, and the power supply for the output circuit 75 of the second-stage photocoupler is current-limited. The resistor R2 is connected to the anode of the light emitting diode 73 of the third-stage photocoupler.
[0012]
Next, the operation will be described. When the ON / OFF control signal output from the trigger circuit 9 drives the light emitting diode 71 of the photocoupler 7a of the first-stage semiconductor switch 1a, the output signal of the photocoupler output circuit 74 becomes LOW. At this time, the output terminal of the output circuit 74 of the first-stage photocoupler is connected to the cathode of the light emitting diode 72 of the second-stage photocoupler, and the power supply for the output circuit 74 of the first-stage photocoupler is a current limiting resistor. It is connected to the anode of the light emitting diode 72 of the second stage photocoupler via R2. Therefore, the light emitting diode 72 of the second-stage photocoupler is driven, and the output signal of the output circuit 75 of the second-stage photocoupler becomes LOW. In response, the output signal of the output circuit 76 of the third-stage photocoupler becomes LOW.
[0013]
Thus, the ON / OFF control signal is sequentially transmitted to the high voltage side. When transmitted to the high voltage side, the signal voltage becomes slower toward the higher voltage side due to the delay of the photocoupler. In order to solve this problem and perform a switching operation simultaneously in each stage, the output signal of the output circuit of the photocoupler is also input to the timing adjustment circuit 8. The timing adjustment circuit 8 detects the rise and fall of the signal and operates the delay circuit. The ON delay time and the OFF delay time can be adjusted separately. The timing of the ON / OFF control signal passing through the timing adjustment circuits 8a, 8b, 8c is adjusted so that the switching operation can be performed simultaneously at each stage. The signals are amplified by the drive circuits 11a, 11b, 11c, and the semiconductor switches 1a, 1b and 1c are driven.
[0014]
【The invention's effect】
As described above, according to the present invention, n-stage (n is a positive integer of 2 or more) semiconductor switches are connected in series with the semiconductor switch connected to the low-voltage section as the first stage, and the last stage is connected to the high-voltage section. Semiconductor switch series-connected body, an n-stage snubber circuit connected in parallel so that a return circuit is common to each semiconductor switch of the semiconductor switch series-connected body, and suppressing a surge voltage, and a semiconductor switch of each stage. ON / OFF control signal is input to each light emitting element, and the ON / OFF control signal transmitted by light is output from the output circuit as an electrical signal, and the n stages of photocouplers are output from the photocoupler of each stage. N-stage timing adjustment circuits for respectively adjusting the timings of the ON / OFF control signals, and input signals from the timing adjustment circuits of each stage are amplified. An n-stage drive circuit for outputting a drive signal to each stage of the semiconductor switch, and a trigger circuit for inputting an ON / OFF control signal to the light emitting element of the first-stage photocoupler, and an output circuit for each stage of the photocoupler The drive circuit of each stage is connected so that the semiconductor switch and the snubber circuit of each stage and the return circuit are common, and power is supplied from the snubber circuit of each stage, and the light emitting element of the n-th stage photocoupler Is connected to the output circuit of the (n-1) th photocoupler so as to be driven based on the ON / OFF control signal output from the output circuit of the (n-1) th photocoupler, and the timing of each stage is adjusted. The circuit turns on / off all the n-stage semiconductor switches at the same time so that the timing of the ON / OFF control signal output from the photocoupler of each stage is sequentially delayed with respect to the first stage. And the adjusted ON / OFF control signals are input to the drive circuits of the respective stages, so that the ON / OFF control signals to the semiconductor switches connected in series are separated by a photocoupler. Are sequentially transmitted through Therefore, since the electric-optical converter and the optical cable can be omitted, there is an effect that the device scale of the high-voltage semiconductor switch circuit can be reduced and it can be manufactured at low cost.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing a high-voltage semiconductor switch circuit according to Embodiment 1 of the present invention;
FIG. 2 is a configuration diagram showing a conventional high-voltage semiconductor switch circuit.
[Explanation of symbols]
1a, 1b, 1c semiconductor switches, 2a, 2b, 2c snubber circuits,
3a, 3b, 3c switch driving circuit, 7a, 7b, 7c photocoupler,
71, 72, 73 Light-emitting diodes of photocouplers,
74, 75, 76 Photocoupler output circuit,
8a, 8b, 8c timing adjustment circuit, 9 trigger circuit,
11a, 11b, 11c Drive circuit.

Claims (3)

A semiconductor switch connected in series with n stages (n is a positive integer of 2 or more) of a semiconductor switch connected to the low-voltage section as a first stage, and a semiconductor switch serial connection body connected in the last stage to the high-voltage section; ,
An n-stage drive circuit connected to each of the n-stage semiconductor switches and outputting a drive signal to the semiconductor switch;
An ON / OFF control signal of each of the n-stage semiconductor switches is input, an ON / OFF control signal transmitted by light is output as an electric signal, and the light-emitting element of the n-th stage photocoupler is n−1 An n-stage photocoupler connected to the output circuit of the (n-1) th photocoupler so as to be driven based on an ON / OFF control signal output from the output circuit of the photocoupler of the stage;
The timing of the ON / OFF control signal output from the n-th stage photocoupler being sequentially delayed with respect to the (n-1) th stage is adjusted so that all the semiconductor switches are simultaneously turned ON / OFF, An n-stage timing adjustment circuit configured to input the adjusted ON / OFF control signal to the drive circuit of each stage;
And a trigger circuit for inputting an ON / OFF control signal to a light emitting element of the photocoupler at the first stage . 2. The high-voltage semiconductor switch circuit according to claim 1, wherein the timing adjustment circuit is configured to adjust the ON control signal and the OFF control signal separately. Each semiconductor switch of the semiconductor switch series connection body is provided with an n-stage snubber circuit connected in parallel so that a return circuit is common to suppress surge voltage, and the snubber circuit includes a zener diode and a capacitor on a return side. A power supply circuit composed of a parallel connection body is added, and the output circuit of each stage of the photocoupler and the drive circuit of each stage are connected so that the semiconductor switch and the snubber circuit of each stage and the return circuit are common, and 3. The high voltage semiconductor switch circuit according to claim 1, wherein power is supplied from a snubber circuit of each stage.

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