CN211046898U

CN211046898U - Bidirectional thyristor low-temperature trigger device

Info

Publication number: CN211046898U
Application number: CN202020010110.7U
Authority: CN
Inventors: 宁永香; 崔建国; 崔建峰; 崔燚; 李光序
Original assignee: Shanxi Institute of Technology
Current assignee: Shanxi Institute of Technology
Priority date: 2020-01-03
Filing date: 2020-01-03
Publication date: 2020-07-17
Anticipated expiration: 2030-01-03

Abstract

The utility model discloses a technology of a bidirectional thyristor low-temperature trigger device, which comprises a photoelectric coupler circuit, a common emitter amplifier circuit, a 220V commercial power circuit, a commercial power voltage reduction circuit, a rectifying circuit, a filter circuit, a voltage stabilizing circuit, a current limiting circuit, a bidirectional thyristor circuit and a load circuit; the output of the photoelectric coupler circuit is connected with a common emitter amplifier circuit, the P1 end of 220V commercial power is subjected to voltage reduction by a voltage reduction circuit, rectification by a rectification circuit, filtering by a filter circuit and voltage stabilization by a voltage stabilizing diode to supply power to a transistor T1, the collector of the transistor T1 is connected with the grid of a thyristor Triac by a current limiting circuit consisting of a resistor R2, and the 220V commercial power passes through the R2_LFirst of the connection TriacThe anode A1, the positive terminal of the capacitor C1, the negative terminal of the diode D2 and the second anode A2 of the Triac are simultaneously connected with the P2 terminal of the 220V mains supply circuit to form a bidirectional thyristor low-temperature trigger device.

Description

Bidirectional thyristor low-temperature trigger device

Technical Field

The utility model relates to a bidirectional thyristor low temperature trigger device's technique, bidirectional thyristor are difficult to be triggered when low temperature, add a common emitter amplifier between opto-coupler and silicon controlled rectifier, and the trigger signal of opto-coupler output can trigger all kinds of silicon controlled rectifiers very easily through the common emitter amplifier enlargies the back, and even the low side opto-coupler also can trigger great powerful silicon controlled rectifier.

Background

Various types of electronic components used in practical applications have a well-known drawback: the temperature-sensitive amplifier is very sensitive to temperature change, particularly semiconductor devices such as diodes, triodes, field effect transistors and the like, static operating parameters of the semiconductor devices can change along with the change of environmental temperature, so that the distortion of amplified signals is caused, which is a problem to be solved, and fortunately, the temperature drift phenomenon can be solved by various means.

It has been shown that when the triac is operating in the switching mode, it also has a temperature-related disadvantage, that is, it cannot operate at low temperature, and when the ambient temperature is low, the triac may not be normally triggered, resulting in that the triac cannot be turned on and only remains in the off state, because at low temperature, the gate of the solid-state switch formed by the triac needs a high-amplitude turn-on (or gate-on) current to trigger the triac, so that the first anode and the second anode are turned on.

The triac is usually triggered by a photo-coupler, which is the most commonly used thyristor trigger circuit, but a general photo-coupler cannot provide a large trigger current (although some high-end photo-couplers can provide a higher output current, they are expensive).

The low-end photoelectric coupler can realize the efficiency of a high-power high-end photoelectric coupler by adopting the method that the low-current trigger signal output by the low-end photoelectric coupler can realize current amplification through a common emitter amplifier, and the larger conducting current generated when the common emitter amplifier is conducted works on the grid of the bidirectional thyristor and the thyristor is triggered.

For the environment with very cold temperature, even the high-end optical coupler can not be triggered, so the scheme can also enhance the environmental adaptability of the electrical equipment.

Disclosure of Invention

The utility model aims to solve the technical problem that a simple structure, novelty, convenient to use, reliable device that is different from conventional silicon controlled rectifier trigger circuit is provided.

In order to achieve the above object, the utility model provides a bidirectional thyristor low temperature trigger device, which is characterized in that, the low temperature trigger device comprises a photoelectric coupler circuit, a common emitter amplifier circuit, a 220V mains supply circuit, a mains supply voltage reduction circuit, a rectification circuit, a filter circuit, a voltage stabilizing circuit, a current limiting circuit, a bidirectional thyristor circuit and a load circuit; the photoelectric coupler circuit is composed of an optical coupler IC1, the common emitter amplifier circuit is composed of a transistor T1 and a resistor R1, a collector of a phototriode in the optical coupler IC1 is connected with a base electrode of the transistor T1, an emitter of the phototriode is connected with a collector of the transistor T1, and the resistor R3 is connected with a step-down capacitor C₂Constitute mains voltage reduction circuit, 220V mains circuit's P1 end warp mains voltage reduction circuit steps down, and diode D1 constitutes rectifier circuit, electrolytic capacitor C1 constitutes filter circuit, zener diode D2 constitutes voltage stabilizing circuit, diode D1's negative terminal and zener diode D2's positive terminal are connected simultaneously to condenser C2's lower extreme, and transistor T1's emitter and capacitor C1's negative terminal are connected simultaneously to diode D1's positive terminal, constitute by Triac, resistance R4, electric capacity C3 Triac circuit, transistor T1's collecting electrode is through constituting by resistance R2 the grid of thyristor Triac is connected to current-limiting circuit, the 220V mains supply passes through resistance R_LThe load circuit is connected with a first anode A1 of the Triac, the positive end of a capacitor C1, the negative end of a diode D2 and a second anode A2 of the Triac, and is simultaneously connected with the P2 end of the 220V mains supply circuit. The capacitance voltage reduction circuit is formed by connecting a capacitor C1 and a resistor R2 in parallel.

In the common emitter amplifier circuit, a resistor R1 is connected between the base and the emitter of the transistor T1.

A resistor R4 and a capacitor C3 are sequentially connected between a first anode A1 and a second anode A2 of the Triac of the bidirectional thyristor circuit.

Drawings

Fig. 1 and 2 are used to provide further understanding of the present invention, which forms a part of the present application, wherein fig. 1 is a conventional connection mode of a photoelectric coupler and a triac, and fig. 2 is an electrical principle of an amplified triac trigger circuit.

Detailed Description

Traditional circuit for triggering bidirectional thyristor by photoelectric coupler

Compared with a mechanical switch, the solid-state electronic switch has many incomparable advantages, the solid-state switch generally utilizes the on-off of a bidirectional thyristor to realize the function of a power supply switch, in the general electronic technology industrial design, the bidirectional thyristor generally utilizes the output current of a photoelectric coupler to trigger the on-off of the bidirectional thyristor, and simultaneously realizes the isolation of strong current and weak current so as to ensure the safety of electronic equipment and human bodies.

The circuit connection mode of the photocoupler triggering the triac is shown in fig. 1, and as can be seen from the figure, the photocoupler IC₁The output signal of the direct connection thyristor Q₂Although the photoelectric receiving tube in the optical coupler also has a current amplification effect, the current amplification capacity of the photoelectric receiving tube is limited due to the technology and cost, and the limited driving capacity of the optical coupler sometimes cannot trigger the conduction of the silicon controlled rectifier when the ambient temperature is low.

Although the driving force of phototriodes of photoelectric couplers of various models is greatly enhanced based on the demand, the price is not so high, and the driving force of most of the photoelectric couplers in the market is still not very large.

2 amplified bidirectional thyristor trigger circuit

The trigger circuit of the bidirectional triode thyristor is different from the traditional trigger mode of the triac commonly used in the industry, the trigger circuit of the bidirectional triode thyristor comprises an amplifier, and the enough current amplification capability of the amplifier can ensure that enough gate current can be obtained to trigger the bidirectional triode thyristor at any temperature, as shown in figure 2.

As can be seen from the figure, the design comprises a photoelectric coupler circuit, a common emitter amplifier circuit, a mains supply voltage reduction circuit, a rectification circuit, a filter circuit, a voltage stabilizing circuit, a current limiting circuit, a bidirectional thyristor circuit, a load circuit and the like.

Common emitter amplifier circuit

By a transistor T₁And a resistance R₁Form a common emitter amplifier, T₁Amplifying the signal from the photoelectric coupler to a sufficient level from T₁Is output through a current limiting resistor R₂A resistor R connected with the grid of the bidirectional thyristor Tric₂The resistance value of the thyristor is not too large, if the resistance value is too large, the driving current of the grid electrode of the Triac is still insufficient, and the drive of the thyristor at low temperature is still not ideal; r₂Too small, the gate voltage of the thyristor is too high, and the gate of the Triac is easily broken down.

Low-voltage power supply circuit of common emitter amplifier

According to the transistor T shown in FIG. 2₁The connection mode with the low-voltage power supply circuit is known as T₁The power supply is negative voltage power supply, the circuit structure is different from the common emitter circuit power supply mode at ordinary times, and in the low-voltage power supply generation circuit, attention is paid to a rectifier diode D₁Filter capacitor C₁A voltage stabilizing diode D₂The polarity arrangement direction of the positive voltage power supply circuit is different from that of a common positive voltage power supply circuit.

The conventional method for converting alternating current commercial power into low-voltage direct current is to use a transformer to reduce voltage and then rectify, filter and stabilize the voltage, but if the limitation of factors such as area and cost is caused, the simplest and practical method is to use a capacitance voltage reduction type principle to realize the acquisition of a low-voltage power supply.

In fig. 2, the low voltage supply of the trigger circuit is supplied by the ac mains, so the mains voltage must be reduced to a level at which the trigger circuit can operate, 220V mains being passed through a resistor R₃Capacitor C₂Directly connected to the circuit, without power transformer, and when the commercial power is positive half cycleTime, capacitance C₁Through voltage stabilizing diode D₂Is charged, at this time, the voltage regulator tube D₂Can provide both pair C₁The charging channel can also realize the purpose of voltage stabilization, and when the negative half cycle of the commercial power is carried out, the commercial power passes through the current limiting resistor R₃Voltage reducing capacitor C₂And a rectifier diode D₁Directional filter capacitor C₁And (4) reverse charging.

Zener diode D₂Stabilizing the negative voltage of DC output to-15V, transistor T₁And base bias resistor R₁The common emitter amplifying circuit is provided with an operating voltage by the negative voltage.

Wherein the capacitor C₂When used as a voltage-reducing resistor, its rated working voltage should not be lower than 400V, preferably 630V, C₂The actual loss of the trigger circuit can be ensured to be 0, and the direct current load presented by the circuit can be prevented from being added to the alternating current power supply. Capacitor C₂The selection of the capacity is calculated according to an empirical formula, and 1uF outputs about 100mA current; attention is paid to the zener diode D₂The capacitor voltage-reducing power supply mode strictly prohibits the voltage-stabilizing tube from being disconnected and operated.

Resistance R₃For limiting the current of the resistor, which is important for the safety of the circuit, the inrush current caused by the instant of the AC power supply is generated by the resistor R₃Limited to a safe level;

at this time T₁The collector of the transistor can be used as the output end of the common emitter amplifier, the emitter is connected with the direct current negative 15V voltage, and the negative voltage can ensure the transistor T₁Can normally operate in the common emitter amplifier mode.

Amplified triac trigger current generation

The control electric signal input by the front stage drives the light emitting source of the photoelectric coupler to emit light, the other end of the isolated light emitting source is received by a light detector (a phototriode and the like) to generate current, the current is further amplified by the phototriode and then output, the conversion of 'electricity- > light- > electricity' is completed, and the functions of input, output and isolation are finally achieved.

Due to the transistor T₁The emitting electrode is at-15V level and is before being amplified by the optical couplerStage control signal enabling transistor T₁Is forward biased to conduct, and a filter capacitor C₁The stored charge can pass through T₁And the gate of the triac Tric, providing a trigger current of about 50mA, a discharge time (i.e., trigger pulse width) of not more than 1 millisecond, R₄/C₃The resistor-capacitor network can protect the triac from the influence of voltage peak.

Aiming at the condition that a common photoelectric coupler can not trigger the bidirectional thyristor at low temperature, a common emitter amplifier is ingeniously added between the optocoupler and the thyristor, so that a trigger signal output by the optocoupler is amplified by the common emitter amplifier, the amplified signal can easily trigger the bidirectional thyristor, and even some optocouplers with low cost can easily trigger the bidirectional thyristor with higher power regardless of the environment in which the bidirectional thyristor is positioned, so that the bidirectional thyristor is a very practical design scheme.

Claims

1. The bidirectional thyristor low-temperature trigger device is characterized in that: the bidirectional thyristor low-temperature trigger device comprises a photoelectric coupler circuit, a common emitter amplifier circuit, a 220V mains supply circuit, a mains supply voltage reduction circuit, a rectification circuit, a filter circuit, a voltage stabilizing circuit, a current limiting circuit, a bidirectional thyristor circuit and a load circuit; the photoelectric coupler circuit is composed of an optical coupler IC1, the common emitter amplifier circuit is composed of a transistor T1 and a resistor R1, a collector of a phototriode in the optical coupler IC1 is connected with a base electrode of the transistor T1, an emitter of the phototriode is connected with a collector of the transistor T1, and the resistor R3 is connected with a step-down capacitor C₂Constitute mains voltage reduction circuit, 220V mains circuit's P1 end warp mains voltage reduction circuit steps down, and diode D1 constitutes rectifier circuit, electrolytic capacitor C1 constitutes filter circuit, zener diode D2 constitutes voltage stabilizing circuit, diode D1's negative terminal and zener diode D2's positive terminal are connected simultaneously to condenser C2's lower extreme, and transistor T1's emitter and capacitor C1's negative terminal are connected simultaneously to diode D1's positive terminal, constitute by Triac, resistance R4, electric capacity C3 Triac circuit, transistor T1's collecting electrode is through being passed through by resistance T1The current limiting circuit formed by R2 is connected with the grid of the silicon controlled Triac, and 220V mains supply passes through a resistor R_LThe load circuit is connected with a first anode A1 of the Triac, the positive end of a capacitor C1, the negative end of a diode D2 and a second anode A2 of the Triac, and is simultaneously connected with the P2 end of the 220V mains supply circuit.

2. The triac cryo-triggering device of claim 1, wherein: in the common emitter amplifier circuit, a resistor R1 is connected between the base and the emitter of the transistor T1.

3. The triac cryo-triggering device of claim 1, wherein: a resistor R4 and a capacitor C3 are sequentially connected between a first anode A1 and a second anode A2 of the Triac of the bidirectional thyristor circuit.