JPS63257327A - Gate circuit for gate turn-off thyristor - Google Patents

Abstract

PURPOSE:To obtain a gate control circuit not affected by electromagnetic induction disturbance by connecting a gate logic circuit and a gate circuit by a fiber scope. CONSTITUTION:A signal giving on/off command of a GTO thyristor 20 is sent through an optical fiber 2 to a gate circuit and separated into a higher gate pulse signal, an on-gate signal and an off-gate signal by a logic circuit GL in the gate circuit. Even with noise applied to a logic circuit GL, after each gate signal is interlocked without destructing the GTO thyristor 20, a signal is given to semiconductor switch elements 14, 15 generating a gate signal pulse to generate a gate pulse driving the GTO thyristor. Thus, the gate circuit of the GTO thyristor immune to external electromagnetic induction noise is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a gate pulse generation circuit for a gate turn-off thyristor used in a railway vehicle control device or a power supply device.

(Prior art) A typical example of a gate circuit of a gate turn-off (hereinafter referred to as GT○) thyristor is shown in Fig. 3. In order to control the on/off of the G'I゛0 thyristor, It is necessary to apply a voltage between the gate and cathode to supply gate power. The peak value and pulse width of each must satisfy the values determined by the applicable GT○ thyristor standard.

In order to obtain such a gate voltage and current, in the conventional gate circuit shown in FIG. 3, signals from a control logic circuit for generating on-pulses and off-pulses are sent to gate pulse generation circuits for on and off pulses separately. Transmit up to Since the potential always changes depending on whether the GTO thyristor 20 driven by the gate circuit is turned on or off, for example, after providing electrical insulation using the pulse transformers 21 and 22 and amplifying the signal using the buffer circuit 7, an on-pulse is generated. For example, semiconductor switching elements 14 and 15 such as transistors are driven to generate pulses at prescribed timings.

(Problem to be solved by the invention) When transmitting the drive signal of the gate circuit using an electric signal,
Inevitably, electromagnetic induction interference occurs due to the switching of the main circuit of the GTO thyristor that is being driven, so-called IT! The gate circuit malfunctions due to atmospheric noise.

The object of the present invention is to provide a control circuit that is not affected by electromagnetic induction disturbances.

[Structure of the invention]

(Means for solving the problem) The present invention includes a gate logic circuit that converts a gate signal into an optical signal and outputs it, an optical transmission line that transmits the optical signal output from the gate logic circuit, and an optical transmission line that transmits the optical signal output from the gate logic circuit. A logic circuit that divides and outputs a gate signal input from a gate logic circuit via a transmission line into a higher gate signal, an off gate signal, and an ongu1- signal, and a gate turn-off thyristor based on the higher gate signal output from this logic circuit. A higher pulse circuit that supplies higher pulses, an off-gate circuit that supplies off-gate pulses to the gate turn-off thyristor based on the off-gate signal output from the logic circuit, and an off-gate circuit that supplies the off-gate pulse to the gate turn-off thyristor based on the on-gate signal output from the logic circuit. An on-gate circuit that supplies an on-gate pulse is provided.

(Function) The gate logic circuit transmits a gate signal to the logic circuit via the optical transmission line. The logic circuit divides the gate signal inputted from the gate logic circuit via the optical transmission line into a higher gate signal, an off-gate signal, and an on-gate signal, and outputs each to a higher pulse circuit, an off-gate circuit, and an on-gate circuit.

The higher pulse circuit supplies a higher pulse to the gate turn-off thyristor based on the higher gate signal output from the logic circuit.

The off-gate circuit supplies an off-gate pulse to the gate turn-off thyristor based on the off-gate signal output from the logic circuit.9' The off-gate circuit supplies an on-gate pulse to the gate turn-off thyristor based on the on-gate signal output from the logic circuit.

(Example) An optical transmitter that converts an electrical signal into an optical signal is provided in a gate logic circuit that generates a gate signal, and the optical signal is reconverted into an electrical signal within the gate circuit that generates a gate pulse of the GTO thyristor. By providing an optical receiver and connecting the optical transmitter and optical receiver with an optical fiber cable, the signal transmission path can be replaced with two electric wires and made into one optical fiber.

The present invention further provides a signal that provides the on-gate pulse, higher gate pulse, and off-gate pulse of the GTO thyristor by converting the on-off two-channel signal, which was conventionally required for one GTO thyristor, into one channel. is generated by a logic circuit provided on the gate circuit side, and it becomes possible to transmit the gate signal using a single optical fiber, whereas the signal was conventionally transmitted using four electric wires.

An embodiment based on the present invention will be described with reference to the drawings. 1st
The figure shows a circuit diagram of a gate circuit of a GTO thyristor according to an embodiment of the present invention.

In the gate circuit according to the present invention, as shown in FIG.
can be conveyed to. There, the electrical signal is converted into an optical signal and transmitted to the gate circuit of the present invention through a single optical fiber.

After the optical signal is reconverted into an electrical signal by the optical receiver 3, it is separated into a higher gate pulse signal, an on-gate signal, and an off-gate signal by a logic circuit within the gate circuit, and even if noise etc. are added to the logic circuit, the GTO After each gate signal is interlocked so as not to destroy the thyristor, a signal is applied to the semiconductor switch element that generates each gate signal pulse, and a pulse is generated to the gate 1 that drives the GTO thyristor.

Components in FIG. 1 that are the same as those shown in FIG. 3 are given the same reference numerals. In FIG. 1, a logic signal that defines the ON or OFF state of the GT○ thyristor is converted into an optical signal by an optical transmitter 1 provided after the gate logic circuit GL. The output of the optical transmitter 1 is transmitted through an optical fiber cable 2.

Installed on the gate circuit side. The signal is transmitted to the optical receiver 3.

On the other hand, the power supply for the gate circuit is AC fat EI AC
and one circuit isolation by transformer lO.

A voltage conversion is performed. The power source is the power source for the higher gate,
The power supply is divided into three parts, an on-gate power supply and an off-gate power supply, and after each is rectified, it is stored as DC power in a capacitor 12 provided in each power supply circuit. The power supply for the optical receiver 3 and the logic circuit connected to the latter stage of the optical receiver is as follows.
It shall be used together with the off-gate power supply. The output of the pre-receiver 49 device 3 is connected to a logic circuit as shown in FIG. On-pulse semiconductor switch 14. and is connected to the off-pulse semiconductor switch 15. Current limiting resistors 16 and 17 are connected in series to the semiconductor switch 13 for the first-year gate pulse and the semiconductor switch 14 for the on-gate pulse. In addition, a bias current limiting resistor 1 is connected in parallel to the off-pulse semiconductor switch.
8 is connected. A gate resistor 19 is connected in parallel between the gate and cathode of the GTO thyristor, which is the output of the gate circuit.

The operation of the gate circuit having the above configuration will be explained using FIG. 2. In FIG. 2, (a) shows the control mode of the GTO thyristor 20, (b) shows the output signal LQ of the gate logic circuit, (
c) is the output signal of the optical receiver 3, (d) and (e) are the output signals of the monostable multivibrator 4, Cf) is the on/off state diagram of the on-pulse switching element 14, (
7) is an on/off state diagram of the higher pulse switching element 13, (7f) is an on/off state diagram of the off pulse switching element 15, and (i) is a current flowing through the higher pulse current limiting resistor 16.

(ri) is the current flowing through the on-gate current limiting resistor 17, (
() is the current flowing through the bias current limiting resistor 18, (I2
) indicates the gate-cathode voltage and gate current of the GTO thyristor 20.

FIG. 2 shows a time chart showing the operation of the gate circuit of the present invention. During the ON period of the control mode of the GTO thyristor prescribed by the gate logic circuit, a signal current ta is applied to the forward resistor 1. , and the optical signal is transmitted by the optical fiber 2 to the optical receiver 3. In this case, the output of the optical receiver 3 is set to be at the "0'" level when receiving light, and to be at the "1" level when receiving a heat signal.

After the output signal of the optical receiver 3 is inverted by the inverter 5, it is transmitted to the semiconductor switch 14, and the semiconductor switch 14 is turned on during the on period.

Also, in synchronization with the rise of the output signal of the inverter 5.

Fixed period 1. The pulse generated by the monostable multivibrator 4 that generates a single pulse with a width of is transmitted to the semiconductor switch 13 only when the output signal of the inverter 5 is "1".
1. Turn on for a period of . The time width of tH is the higher gate pulse width required by the GTO thyristor 20 standard.

Similarly, the pulse generated by the monostable multivibrator 4, which generates a single pulse with a width of a certain time tp in synchronization with the rise of the output signal of the inverter 5, is A N l) with the output signal of the optical receiver 3. Under certain conditions, only when the output signal of the optical receiver 3 is P1''', it is transmitted to the semiconductor switch 15 to turn on the semiconductor switch 15 for a period of tF. The bias current limiting resistor 18 and the gate resistor 19 divide the off-gate voltage during the period when all the semiconductor switches are off, and turn off the gate and cathode of the GTO thyristor 20. A predetermined off-bias voltage is applied between them.Thus, the signal transmission to the gate circuit can be carried out economically by a pair of optical links.

It is possible to construct a gate circuit for a GT○ thyristor that is resistant to electromagnetic induction noise from the outside.

(Other Embodiments) In FIG. 1, the circuit for generating the higher gate pulse is provided independently from the ON gate pulse circuit, but in order to simplify the circuit configuration, the semiconductor switch 13
It is also possible to omit the drive circuit and adopt a configuration in which a higher gate speed-up capacitor 23 is connected in parallel to the ON cable 1/current limiting resistor 17 as shown in FIG.

〔Effect of the invention〕

As described above, according to the present invention, it is strong against electromagnetic induction noise, and since the gate logic circuit and the gate circuit are connected by an insulating material called a fiberscope, the potential of the gate circuit is Wandering power transformer 1
0 can be made as high as possible, and characteristics suitable for a gate circuit of a high voltage converter can be provided.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a goo circuit according to an embodiment of the present invention, and FIG. 2 is a time chart diagram of an embodiment of the present invention.
FIG. 3 shows the conventional game 1-I! The circuit diagram of IN is shown. 1... Optical transmitter 2... Optical fiber 3... Optical receiver 4... Monostable multivibrator 5... Inverting logic gate 6... Adding logic gate 7...
・Buffer gate 1o...tt [f transformer 11... rectifier circuit 12...
Capacitor 13... Higher pulse switch 14... ON pulse switch 15... OFF pulse switch 16... Higher pulse fIt flow\IJ limiting resistor 17.
...On-gate current limiting resistance 18...Bias current infinite resistance゛19...Gate resistance 2o...GTO
Thyristor diagram 2

Claims (1)

[Scope of Claims] A gate logic circuit that converts a gate signal into an optical signal and outputs it; an optical transmission line that transmits the optical signal output from this gate logic circuit; a logic circuit that divides and outputs a gate signal inputted from the gate signal into a higher gate signal, an off-gate signal, and an on-gate signal, and a higher pulse circuit that supplies a higher pulse to a gate turn-off thyristor based on the higher gate signal output from this logic circuit; an off-gate circuit that supplies an off-gate pulse to the gate turn-off thyristor based on an off-gate signal output from the logic circuit; and an on-gate circuit that supplies an on-gate pulse to the gate turn-off thyristor based on an on-gate signal output from the logic circuit. A gate circuit for a gate turn-off thyristor comprising: