CN207234751U - A kind of trigger circuit for breaker - Google Patents

Abstract

The utility model discloses a trigger circuit for a circuit breaker, which comprises an accelerating capacitor circuit, an optocoupler isolation chip and a trigger circuit, wherein the trigger voltage signal triggers the optocoupler isolation chip through the acceleration capacitor circuit, and the optocoupler isolation chip passes through the trigger circuit Send a trigger signal. The utility model not only effectively reduces the trigger delay, shortens the trigger reaction time to about 100nS, but also has a wider range of acceptable trigger voltages, and the trigger voltage in the utility model can reach DC30V-DC300V.

Description

A trigger circuit for a circuit breaker

technical field

The utility model relates to a trigger circuit, in particular to a trigger circuit for a circuit breaker.

Background technique

The operating voltage test technology of the circuit breaker operating mechanism is one of the important guarantees for the safe operation of the power system. The trigger circuit design of the operating voltage is very important. At present, the commonly used trigger circuits at home and abroad are circuits that do not include accelerating capacitors.

The trigger circuit structure diagram in the prior art, as shown in Figure 1, includes an optocoupler isolation chip 1 and a trigger circuit 2, the trigger voltage signal passes through the resistor _R1 , then enters the second pin of the optocoupler isolation chip, and is transmitted from the optocoupler The third pin of the coupled isolation chip forms a loop. Under normal circumstances, the sixth pin of the optocoupler isolation chip outputs a high level because of the pull-up resistor _R2 . When there is a trigger voltage signal, this pin becomes a low level, and this signal is a trigger signal.

The disadvantage of this trigger circuit is that due to the limitation of the PCB package size, the current power of resistor _R1 is 2W. In order to make the trigger circuit work normally under the trigger voltage of DC300V, the resistance value of resistor _R1 must be greater than R=U ² /P= 300 ² /2＝45KΩ, the typical conduction current of the common optocoupler isolation chip is 2mA～15mA, in order to make the optocoupler isolation chip work normally, the minimum current is 2mA, so the minimum trigger voltage is only U＝IR＝90V.

In summary, the trigger voltage range of common trigger circuits on the market is narrow, which no longer meets the requirements of low-voltage actuation tests for circuit breakers with low actuation voltages.

Utility model content

Purpose of the utility model: The utility model aims at the problems existing in the prior art, and provides a trigger circuit for a circuit breaker with a fast response speed and a wide trigger voltage range.

Technical solution: The utility model provides a trigger circuit for a circuit breaker, including an accelerating capacitor circuit, an optocoupler isolation chip and a trigger circuit, wherein the trigger voltage signal triggers the optocoupler isolation chip through the acceleration capacitor circuit, and the optocoupler isolation chip The trigger signal is sent through the trigger loop; the accelerating capacitor loop includes a third resistor R ₃ , a fourth resistor R ₄ , a first capacitor C ₁ and a diode D ₁ , wherein one end of the third resistor R ₃ is connected to the trigger voltage and the first capacitor respectively. One end of the four resistors _R4 is connected, the other end of the third resistor _R3 is connected to one end of the first capacitor _C1 , and the other end of the first capacitor _C1 is respectively isolated from the fourth resistor _R4 , the cathode of the diode _D1 and the optocoupler The second pin of the chip is connected, and the anode of the diode _D1 is respectively connected to the third pin of the optocoupler isolation chip, the trigger voltage and the ground.

Further, the third resistor _R3 is 5.1KΩ, the fourth resistor _R4 is 27KΩ, and the second resistor _R2 is 1KΩ. In this way, the optocoupler isolation chip can be effectively protected, and the trigger voltage can reach DC30V-DC300V at the same time, so as to ensure the normal operation of the trigger circuit.

Further, the capacitance of the first capacitor _C1 is 0.1uF. While ensuring that the trigger signal can be normally generated, the volume of the entire trigger circuit is effectively reduced.

Further, the model of the diode D ₁ is 1N4148. Diode D1 is a reverse protection diode. Using this type of diode can better protect the optocoupler isolation chip from being damaged when the trigger voltage is reversed.

Further, the model of the optocoupler isolation chip is 6N137. The optocoupler isolation chip 6N137 is a high-speed optocoupler, and the typical conversion delay is less than 30 nanoseconds, which is beneficial to reduce the trigger delay time.

Beneficial effects: Compared with the prior art, the utility model not only effectively reduces the trigger delay, shortens the trigger reaction time to about 100nS, but also has a wider range of acceptable trigger voltages. The trigger voltage in the utility model can reach DC30V ~ DC300V; at the same time, effectively reducing the size of the entire trigger circuit.

Description of drawings

Fig. 1 is the trigger circuit adopted in the prior art;

Fig. 2 is a circuit diagram of the trigger circuit provided by the utility model.

Detailed ways

Below in conjunction with accompanying drawing, the utility model is further explained.

As shown in Figure 2, the utility model discloses a trigger circuit for a circuit breaker, including an accelerating capacitor circuit 3, an optocoupler isolation chip 1 and a trigger circuit 2, wherein the trigger voltage signal triggers the optocoupler through the accelerating capacitor circuit 3 The isolation chip 1, the optocoupler isolation chip 1 sends a trigger signal through the trigger circuit 2.

Wherein, the accelerating capacitor circuit 3 includes a third resistor R ₃ , a fourth resistor R ₄ , a first capacitor C ₁ and a diode D ₁ , one end of the third resistor R ₃ is respectively connected to the trigger voltage and one end of the fourth resistor R ₄ , The other end of the third resistor _R3 is connected to one end of the first capacitor _C1 , and the other end of the first capacitor _C1 is respectively connected to the fourth resistor _R4 , the cathode of the diode _D1 and the second pin of the optocoupler isolation chip, The anode of the diode _D1 is respectively connected to the third pin of the optocoupler isolation chip, the trigger voltage and the ground. The trigger circuit 2 includes a second resistor R ₂ , one end of the second resistor R ₂ is connected to the sixth pin of the optocoupler isolation chip, and the other end of the second resistor R ₂ is connected to the seventh pin, the eighth pin of the optocoupler isolation chip. pin and a 3.3V power supply connection. The sixth pin of the optocoupler isolation chip is the trigger signal output end, and the fifth pin of the optocoupler isolation chip is grounded.

In this embodiment, the third resistor _R3 is 5.1KΩ, the fourth resistor _R4 is 27KΩ, and the second resistor _R2 is 1KΩ; the capacitance values of the first capacitor C1 and the first capacitor C1 are both 0.1uF; the diode D The model of ₁ is 1N4148; the model of optocoupler isolation chip is 6N137. Among them, the pin functions of the optocoupler isolation chip 6N137 are shown in Table 1.

Table 1

pin Function pin 1 not connected pin 2 diode anode pin 3 diode cathode pin 4 not connected pin 5 land pin 6 output pin 7 output enable pin 8 Power not connected

The trigger voltage signal passes through the third resistor R ₃ , the fourth resistor R ₄ and the first capacitor C ₁ , and then enters the second pin of the optocoupler isolation chip, and forms a loop from the third pin of the optocoupler isolation chip. The seventh pin of the optocoupler isolation chip is connected in parallel with the eighth pin. Under normal circumstances, the sixth pin of the optocoupler isolation chip outputs a high level because of the pull-up resistor, that is, the second resistor _R2 . When there is a trigger voltage signal , the sixth pin becomes low level, this signal is a trigger signal.

Generally, for circuit breakers with DC110V operating voltage, since the operating voltage of the low-voltage operating voltage test is 30% of the rated operating voltage, the voltage of the low-voltage operating voltage test is DC30V. In order to take into account the trigger voltage of DC30V, an accelerating capacitor circuit is designed. The resistance of the third resistor R ₃ is 5.1KΩ. When the trigger voltage occurs, the first capacitor C ₁ is equivalent to a short circuit. At this time, the trigger current is 30V/5.1K =6mA, so that the conduction of the optocoupler isolation chip can be met instantly. When the first capacitor _C1 is charged and saturated, the branch current is cut off, and the voltage signal is loaded to the optocoupler isolation chip through the fourth resistor _R4 to ensure that the optocoupler isolation chip is in the conduction state during the whole triggering process.

The above is only a preferred embodiment of the utility model, it should be pointed out that for those of ordinary skill in the art, without departing from the principle of the utility model, some improvements and modifications can also be made. Retouching should also be regarded as the scope of protection of the present utility model.

Claims (5)

1. A kind of 1. trigger circuit for breaker, it is characterised in that：Including speed-up capacitor circuit, light-coupled isolation chip and triggering Circuit, wherein, trigger voltage signal triggers light-coupled isolation chip by speed-up capacitor circuit, and light-coupled isolation chip is by triggering back Road sends trigger signal；The speed-up capacitor circuit includes 3rd resistor R₃, the 4th resistance R₄, the first capacitance C₁With diode D₁, Wherein, 3rd resistor R₃One end respectively with trigger voltage and the 4th resistance R₄One end connection, 3rd resistor R₃The other end with First capacitance C₁One end connection, the first capacitance C₁The other end respectively with the 4th resistance R₄, diode D₁Anode and optocoupler every The second pin connection of off-chip piece, diode D₁Cathode the 3rd pin, trigger voltage and the ground with light-coupled isolation chip respectively Connection.
2. 2. the trigger circuit according to claim 1 for breaker, it is characterised in that：The trigger circuit includes second Resistance R₂, second resistance R₂One end and light-coupled isolation chip the 6th pin connect, second resistance R₂The other end and optocoupler every The 7th pin, the 8th pin of off-chip piece are connected with the power supply of 3.3V, the 3rd resistor R₃For 5.1K Ω, the 4th resistance R₄For 27K Ω, second resistance R₂For 1K Ω.
3. 3. the trigger circuit according to claim 1 for breaker, it is characterised in that：First capacitance C₁Capacitance be 0.1uF。
4. 4. the trigger circuit according to claim 1 for breaker, it is characterised in that：The diode D₁Model 1N4148。
5. 5. the trigger circuit according to claim 1 for breaker, it is characterised in that：The type of the light-coupled isolation chip Number it is 6N137.