HKT thyristor switching control circuit

Abstract

The utility model discloses an HKT thyristor switching control circuit in the technical field of thyristor switching, which comprises an electronic switch III, the electronic switch III is respectively connected with a composite electronic switch I and a composite electronic switch II, the composite electronic switch I is connected with an A-phase trigger drive circuit, and the composite electronic switch II is connected with a B-phase trigger drive circuit. And the compound electronic switch II is connected with the C-phase trigger drive circuit. The electronic switch III is used for controlling two electronic switch circuits at the rear stage to realize general control; the composite post-stage electronic switch controls the A-phase thyristor and the C-phase thyristor, so that the control function of switching signals is realized, the structure is simple, the anti-interference performance is better, the flash switching phenomenon can be eliminated, and the stability of the product is improved.

Description

Technical Field

[0001] The utility model relates to a switching control circuit in the technical field of thyristor switching switches. Background Art

[0002] The thyristor switching switch is an electronic device that is mainly used to control the on-off state of the current. It consists of multiple parts such as thyristors, switching control circuits, and trigger circuits. It is an electronic device that can achieve load switching without inrush current. The working principle of the thyristor switching switch is to realize the switching operation of the circuit by triggering and controlling the thyristors. Its core part is the switching control circuit, which outputs a certain trigger pulse to turn on the thyristor so that the load is connected to the power grid. In the power quality system, the thyristor switching switch is used as a switch actuator to connect the power compensation capacitor to the power grid, compensate for reactive power, reduce reactive current in the power grid, and improve the power factor. Phase A and phase C of the three-phase electricity need to be controlled by controlling the thyristor to control their on and off, while phase B is directly connected and does not need to be controlled. In the prior art, a thyristor switching switch occasionally experiences a brief flashing phenomenon in the cut-off state, that is, the thyristor is briefly turned on, and the on-off of the thyristor depends on whether the optocoupler works or not. Therefore, it can be judged that the brief conduction of the optocoupler is caused by the control circuit being subjected to unknown interference, resulting in malfunction, and its stability is insufficient (see attached Figure 1-2 ). Utility Model Content

[0003] The utility model aims to provide a HKT thyristor switching control circuit, which has a simple structure and good anti-interference performance, can eliminate the flashover phenomenon and improve the stability of the product.

[0004] To achieve the above-mentioned purpose, the utility model provides an HKT thyristor switching control circuit, including an electronic switch three, wherein the electronic switch three is respectively connected to a composite electronic switch one and a composite electronic switch two, the composite electronic switch one is connected to an A-phase trigger drive circuit, and the composite electronic switch two is connected to a C-phase trigger drive circuit.

[0005] Compared with the prior art, the beneficial effect of the utility model lies in that the overall control is realized by using three electronic switches to control two electronic switch circuits of the rear stage; the composite rear-stage electronic switch controls two thyristors of phase A and phase C, thereby realizing the control function of the switching signal, having a simple structure and good anti-interference performance, which can eliminate the flashover phenomenon and improve the stability of the product.

[0006] As a further improvement of the present utility model, the electronic switch three includes a transistor T1, the base of the transistor T1 is connected to the overheat protection signal of the thyristor switching switch via the resistor R4, the emitter of the transistor T1 is grounded, the collector of the transistor T1 is respectively connected to one end of the resistor R1, one end of the resistor R2 and one end of the resistor R3, the other end of the resistor R1 is connected to the positive electrode of the 12V power supply, the other end of the resistor R2 is connected to the positive electrode of the light-emitting diode V2, the negative electrode of the light-emitting diode V2 is connected to the composite electronic switch two, the other end of the resistor R3 is connected to the positive electrode of the light-emitting diode V1, and the negative electrode of the light-emitting diode V1 is connected to the composite electronic switch one.

[0007] In this way, the overheat protection signal is at a low level, so the transistor T1 is cut off, and the collector of the transistor T1 is not conductive to the ground. The +12V power supply is divided into two paths after passing through the resistor R1. One path is added to the composite electronic switch 2 through the resistor R2 and the light-emitting diode V2, and the other path is added to the composite electronic switch 1 through the resistor R3 and the light-emitting diode V1, giving control signals to these two composite post-stage electronic switches.

[0008] As a further improvement of the utility model, a composite electronic switch includes a transistor T2, the base of the transistor T2 is connected to the cathode of the light-emitting diode V1, the collector of the transistor T2 is connected to the A-phase trigger drive circuit, the emitter of the transistor T2 is connected to the collector of the transistor T3, the emitter of the transistor T3 is grounded, and the base of the transistor T3 is connected to the external control signal via the resistor R5.

[0009] In this way, the composite post-stage electronic switch uses one of the transistors to control the on / off of the other transistor, thereby realizing the control function of the switching signal.

[0010] As a further improvement of the utility model, the A-phase trigger drive circuit includes an optocoupler D1, wherein pin 1 of the optocoupler D1 is connected to the positive electrode of the 12V power supply via a resistor R8, pins 2 and 3 of the optocoupler D1 are connected to pin 1 of the optocoupler D2, pins 2 and 3 of the optocoupler D2 are connected to the collector of the transistor T2, pin 6 of the optocoupler D1 is connected to the K pole of the A-phase thyristor, pin 4 of the optocoupler D1 is connected to pin 6 of the optocoupler D2, and pin 4 of the optocoupler D2 is connected to the G pole of the A-phase thyristor.

[0011] In this way, the on and off of the two optocouplers are controlled by the transistor to drive the thyristor, thereby controlling the switching state of phase A.

[0012] As a further improvement of the utility model, the composite electronic switch 2 includes a transistor T4, the base of the transistor T4 is connected to the negative electrode of the light-emitting diode V2, the collector of the transistor T4 is connected to the C-phase trigger drive circuit, the emitter of the transistor T4 is connected to the collector of the transistor T5, the emitter of the transistor T5 is grounded, the base of the transistor T5 is connected to one end of the resistor R6, the other end of the resistor R6 is respectively connected to the external control signal and one end of the resistor R7, and the other end of the resistor R7 is connected to the emitter of the transistor T5.

[0013] In this way, the composite post-stage electronic switch uses one of the transistors to control the on / off of the other transistor, thereby realizing the control function of the switching signal.

[0014] As a further improvement of the present utility model, the C-phase trigger drive circuit includes an optocoupler D3, wherein pin 1 of the optocoupler D3 is connected to the positive electrode of the 12V power supply via a resistor R9, pins 2 and 3 of the optocoupler D3 are connected to pin 1 of the optocoupler D4, pins 2 and 3 of the optocoupler D4 are connected to the collector of the transistor T4, pin 6 of the optocoupler D3 is connected to the K pole of the C-phase thyristor, pin 4 of the optocoupler D3 is connected to the 6 pin of the optocoupler D4, and pin 4 of the optocoupler D4 is connected to the G pole of the C-phase thyristor.

[0015] In this way, the on and off of the two optocouplers are controlled by the transistor to drive the thyristor, thereby controlling the switching state of the C phase. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a circuit block diagram in the prior art.

[0017] Figure 2 It is a circuit schematic diagram in the prior art.

[0018] Figure 3 This is a circuit block diagram of the utility model.

[0019] Figure 4 This is the circuit schematic diagram of the utility model. DETAILED DESCRIPTION

[0020] The utility model is further described below in conjunction with the accompanying drawings:

[0021] like Figure 3-4 The HKT thyristor switching control circuit shown includes an electronic switch three, which is respectively connected to a composite electronic switch one and a composite electronic switch two, the composite electronic switch one is connected to an A-phase trigger drive circuit, and the composite electronic switch two is connected to a C-phase trigger drive circuit.

[0022] The electronic switch three includes a transistor T1, the base of the transistor T1 is connected to the overheat protection signal of the thyristor switching switch via a resistor R4, the emitter of the transistor T1 is grounded, the collector of the transistor T1 is connected to one end of the resistor R1, one end of the resistor R2 and one end of the resistor R3 respectively, the other end of the resistor R1 is connected to the positive electrode of the 12V power supply, the other end of the resistor R2 is connected to the positive electrode of the light emitting diode V2, the negative electrode of the light emitting diode V2 is connected to the composite electronic switch two, the other end of the resistor R3 is connected to the positive electrode of the light emitting diode V1, and the negative electrode of the light emitting diode V1 is connected to the composite electronic switch one.

[0023] The composite electronic switch 1 includes a transistor T2, the base of the transistor T2 is connected to the cathode of the light-emitting diode V1, the collector of the transistor T2 is connected to the A-phase trigger drive circuit, the emitter of the transistor T2 is connected to the collector of the transistor T3, the emitter of the transistor T3 is grounded, and the base of the transistor T3 is connected to the external control signal via the resistor R5.

[0024] The A-phase trigger drive circuit includes an optocoupler D1, wherein pin 1 of the optocoupler D1 is connected to the positive electrode of the 12V power supply via a resistor R8, pins 2 and 3 of the optocoupler D1 are connected to pin 1 of the optocoupler D2, pins 2 and 3 of the optocoupler D2 are connected to the collector of the transistor T2, pin 6 of the optocoupler D1 is connected to the K-pole of the A-phase thyristor, pin 4 of the optocoupler D1 is connected to pin 6 of the optocoupler D2, and pin 4 of the optocoupler D2 is connected to the G-pole of the A-phase thyristor.

[0025] The composite electronic switch 2 includes a transistor T4, a base of the transistor T4 is connected to the cathode of the light-emitting diode V2, a collector of the transistor T4 is connected to the C-phase trigger drive circuit, an emitter of the transistor T4 is connected to the collector of the transistor T5, the emitter of the transistor T5 is grounded, a base of the transistor T5 is connected to one end of a resistor R6, the other end of the resistor R6 is respectively connected to an external control signal and one end of a resistor R7, and the other end of the resistor R7 is connected to the emitter of the transistor T5.

[0026] The C phase trigger drive circuit includes an optocoupler D3, wherein pin 1 of the optocoupler D3 is connected to the positive electrode of the 12V power supply via a resistor R9, pins 2 and 3 of the optocoupler D3 are both connected to pin 1 of the optocoupler D4, pins 2 and 3 of the optocoupler D4 are both connected to the collector of the transistor T4, pin 6 of the optocoupler D3 is connected to the K pole of the C phase thyristor, pin 4 of the optocoupler D3 is connected to the 6 pin of the optocoupler D4, and pin 4 of the optocoupler D4 is connected to the G pole of the C phase thyristor.

[0027] In the utility model, the external control signal is a signal sent by an external multi-channel controller of the thyristor switching switch, and the overheat protection signal is a protection signal generated inside the thyristor switching switch.

[0028] When the thyristor switch is powered on but not working, the overheat protection signal is low level, and the external control signal of the thyristor switch is low level. Because the overheat protection signal is low level, the transistor T1 is cut off, and the collector of the transistor T1 is not conductive to the ground. The +12V power supply is divided into two paths after passing through the resistor R1. One path is added to the base of the transistor T4 through the resistor R2 and the light-emitting diode V2, and the other path is added to the base of the transistor T2 through the resistor R3 and the light-emitting diode V1. Because the control signal is low level, the transistors T3 and T5 are cut off, so although there is voltage on the base of the transistors T2 and T4, the emitters of the transistors T2 and T4 are open to the ground and do not meet the conduction conditions, so the optocouplers D1-D4 are not conductive.

[0029] When the thyristor switching switch is powered on, the overheat protection signal is low level and the external control signal is high level. Because the overheat protection signal is low level, the transistor T1 is cut off, and the collector of the transistor T1 is not conducting to the ground. The +12V power supply is divided into two paths after passing through the resistor R1. One path is added to the base of the transistor T4 through the resistor R2 and the light-emitting diode V2, and the other path is added to the base of the transistor T2 through the resistor R3 and the light-emitting diode V1. Because the external control signal is high level, the transistors T3 and T5 are turned on, so the transistors T2 and T4 are turned on, triggering the drive optocoupler D1-D4 to turn on. The light-emitting diodes V1 and V2 are on, indicating that the A phase and the C phase are in the input state.

[0030] When the temperature of the thyristor switching switch is too high, the overheat protection signal is high, the be-pole of transistor T1 has a bias voltage and is turned on, the collector of transistor T1 is turned on to the ground, the collector of transistor T1 is low, and transistors T2 and T4 lose the be-pole bias voltage and are turned off. Optocouplers D1-D4 are not turned on. At this time, whether the external control signal is high or low, it does not affect the cut-off state of transistors T2 and T4.

[0031] In addition, this circuit can suppress the same-phase pulse interference in the cut-off state and will not be automatically switched on. Negative pulse interference: the overheat protection signal and the external control signal are both low-level, transistors T3 and T5 are cut off, so transistors T2 and T4 are cut off, and optocouplers D1-D4 are not conducting; positive pulse interference: the overheat protection signal and the external control signal are both high-level, transistor T1 is cut off, so transistors T2 and T4 are cut off, and optocouplers D1-D4 are not conducting.

[0032] The utility model controls the on-off of the circuit by means of an external control signal and an overheat protection signal inside the thyristor switching switch, and realizes the control function by changing the composition of the triode, thereby controlling the switching state of the A phase and the C phase. The overall structure is simple, and has good anti-interference performance, can eliminate the flashover phenomenon, and improves the stability of the product.

[0033] The present utility model is not limited to the above-mentioned embodiments. On the basis of the technical solution disclosed herein, technicians in this field can make some substitutions and deformations to some technical features therein according to the disclosed technical content without creative labor, and these substitutions and deformations are all within the protection scope of the present utility model.

Claims

1. A HKT thyristor switching control circuit, characterized in that: It includes an electronic switch three, which is respectively connected to a composite electronic switch one and a composite electronic switch two, the composite electronic switch one is connected to an A-phase trigger drive circuit, and the composite electronic switch two is connected to a C-phase trigger drive circuit.

2. The HKT thyristor switching control circuit according to claim 1, characterized in that: The electronic switch three includes a transistor T1, the base of the transistor T1 is connected to the overheat protection signal of the thyristor switching switch via a resistor R4, the emitter of the transistor T1 is grounded, the collector of the transistor T1 is connected to one end of the resistor R1, one end of the resistor R2 and one end of the resistor R3 respectively, the other end of the resistor R1 is connected to the positive electrode of the 12V power supply, the other end of the resistor R2 is connected to the positive electrode of the light emitting diode V2, the negative electrode of the light emitting diode V2 is connected to the composite electronic switch two, the other end of the resistor R3 is connected to the positive electrode of the light emitting diode V1, and the negative electrode of the light emitting diode V1 is connected to the composite electronic switch one.

3. The HKT thyristor switching control circuit according to claim 2, characterized in that: The composite electronic switch 1 includes a transistor T2, the base of the transistor T2 is connected to the cathode of the light-emitting diode V1, the collector of the transistor T2 is connected to the A-phase trigger drive circuit, the emitter of the transistor T2 is connected to the collector of the transistor T3, the emitter of the transistor T3 is grounded, and the base of the transistor T3 is connected to the external control signal via the resistor R5.

4. The HKT thyristor switching control circuit according to claim 3, characterized in that: The A-phase trigger drive circuit includes an optocoupler D1, wherein pin 1 of the optocoupler D1 is connected to the positive electrode of the 12V power supply via a resistor R8, pins 2 and 3 of the optocoupler D1 are connected to pin 1 of the optocoupler D2, pins 2 and 3 of the optocoupler D2 are connected to the collector of the transistor T2, pin 6 of the optocoupler D1 is connected to the K-pole of the A-phase thyristor, pin 4 of the optocoupler D1 is connected to pin 6 of the optocoupler D2, and pin 4 of the optocoupler D2 is connected to the G-pole of the A-phase thyristor.

5. The HKT thyristor switching control circuit according to claim 4, characterized in that: The composite electronic switch 2 includes a transistor T4, a base of the transistor T4 is connected to the cathode of the light-emitting diode V2, a collector of the transistor T4 is connected to the C-phase trigger drive circuit, an emitter of the transistor T4 is connected to the collector of the transistor T5, the emitter of the transistor T5 is grounded, a base of the transistor T5 is connected to one end of a resistor R6, the other end of the resistor R6 is respectively connected to an external control signal and one end of a resistor R7, and the other end of the resistor R7 is connected to the emitter of the transistor T5.

6. The HKT thyristor switching control circuit according to claim 5, characterized in that: The C phase trigger drive circuit includes an optocoupler D3, wherein pin 1 of the optocoupler D3 is connected to the positive electrode of the 12V power supply via a resistor R9, pins 2 and 3 of the optocoupler D3 are both connected to pin 1 of the optocoupler D4, pins 2 and 3 of the optocoupler D4 are both connected to the collector of the transistor T4, pin 6 of the optocoupler D3 is connected to the K pole of the C phase thyristor, pin 4 of the optocoupler D3 is connected to the 6 pin of the optocoupler D4, and pin 4 of the optocoupler D4 is connected to the G pole of the C phase thyristor.

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