Switching switch driving circuit applied to large-current short-network compensation of submerged arc furnace

Abstract

The utility model discloses a fling-cut switch driving circuit applied to large-current short-network compensation of a submerged arc furnace, which is provided with a power supply circuit, a trigger control circuit, a zero-crossing comparator circuit, a D latch circuit, a contactor output control circuit, an N555 timer circuit, a triode amplifying circuit and a forward and reverse thyristor driving circuit. According to the utility model, a control signal can be output to the contactor while no impact inrush current is ensured when a capacitor is input during zero-crossing triggering of the thyristor, so that the function of long-time current conduction is completed by the contactor, zero-crossing is input, huge heating and loss generated during operation of the thyristor are avoided, the contactor does not generate arc discharge, and the service life of the contactor is prolonged. And the service life is prolonged from electrical service life to mechanical service life, so that maintenance-free, safe and stable operation of short network compensation products in the submerged arc furnace industry in the whole life cycle is realized.

Description

Technical Field

[0001] The utility model relates to the technical field of large current short network compensation for submerged arc furnaces, in particular to a switching switch driving circuit applied to large current short network compensation for submerged arc furnaces. Background Art

[0002] The purpose of high-current short-circuit compensation for an electric furnace is to allow the capacitor load to be switched on and off at the zero-crossing moment to avoid the impact of the closing surge current, which can greatly increase the service life of the capacitor. The commonly used technology at present is to use mechanical switch contactors for switching. Since the life of the capacitors and contactors used in high-current short-circuit compensation for electric furnaces is very short, and problems and risks such as fire and capacitor explosion often occur, the safety is poor and the failure rate is high, resulting in huge maintenance costs. This has been a huge pain point in the electric furnace industry for many years. Utility Model Content

[0003] In view of this, the utility model proposes a switching switch driving circuit for high current short network compensation of an electric arc furnace, which can solve the defects of poor safety and high failure rate caused by the short life of capacitors and contactors in the prior art.

[0004] The technical solution of the utility model is achieved in this way:

[0005] A switching switch driving circuit for high-current short-circuit compensation of an ore-heating furnace comprises a power supply circuit, a trigger control circuit, a zero-crossing comparison circuit, a D latch circuit, a contactor output control circuit, an N555 timer circuit, a triode amplifier circuit and a forward and reverse thyristor driving circuit, wherein the trigger control circuit and the zero-crossing comparison circuit are connected to the D latch circuit, the D latch circuit is connected to the N555 timer circuit and the contactor output control circuit, the N555 timer circuit is connected to the triode amplifier circuit, and the triode amplifier circuit is connected to the forward and reverse thyristor driving circuit to output a bidirectional thyristor zero-crossing trigger synchronous pulse to control the opening and closing of the bidirectional thyristor.

[0006] As a further optional scheme for the switching switch driving circuit applied to high-current short-circuit compensation of the electric arc furnace, the power supply circuit is connected in parallel with the varistor R0 at the input end of the power transformer TS0, and the rectifier bridge is connected at the output end of the power transformer TS0. The output end of the rectifier bridge is respectively connected in parallel with the capacitor C1, the voltage regulator T0, the capacitor C2, the resistor R1, the light-emitting diode L0 and the adjustable resistor R0.

[0007] As a further optional scheme for the switching switch driving circuit applied to the high-current short-circuit compensation of the electric arc furnace, a resistor R101 is connected in parallel between the trigger end K of the trigger control circuit and the power supply VCC, one end of the resistor R101 is connected to the resistor R102, the other end of the resistor R102 is connected to the capacitor C101, the other end of the capacitor C101 is connected to the power supply VCC and the resistor R105, the other end of the resistor R102 is connected to the resistor R103, the other end of the resistor R103 and the other end of the resistor R105 are respectively connected to the transistor T2, and the other end of the resistor R105 is also connected to the D latch circuit.

[0008] As a further optional scheme for the switching switch driving circuit applied to high-current short-circuit compensation of an electric arc furnace, the K1 end and the K2 end of the zero-crossing comparison circuit are respectively connected to resistor R119 and resistor R118, the other ends of resistor R119 and resistor R118 are respectively connected to the second pin and the fourth pin of the optocoupler U2, the sixth pin of the optocoupler U2 is connected to resistor R110 and the third pin of the U0 operational amplifier circuit, the other end of R110 is connected to the power supply VCC, the fourth pin and the eighth pin of the U0 operational amplifier circuit are respectively grounded and the power supply VCC, the first pin of the U0 operational amplifier circuit is connected to resistor R111 and the D latch circuit, and the other end of the resistor R111 is grounded.

[0009] As a further optional scheme for the switching switch driving circuit applied to high-current short-circuit compensation of an electric arc furnace, the eighth pin of the D latch circuit is connected to the zero-crossing comparison circuit, the thirteenth pin of the D latch circuit is connected to the trigger control circuit, the first pin, the ninth pin, and the eleventh pin of the D latch circuit are connected together, the twelfth pin and the thirteenth pin of the D latch circuit are connected together, the sixth pin and the tenth pin of the D latch circuit are connected together, the third pin and the fifth pin of the D latch circuit are connected together, the second pin and the fourth pin of the D latch circuit are connected together, and the second pin of the D latch circuit is connected to the contactor output control circuit and the N555 timer circuit.

[0010] As a further optional scheme for the switching switch driving circuit applied to the high-current short-circuit compensation of the electric arc furnace, the resistor R5 of the contactor output control circuit is connected to the D latch circuit, the other end of the resistor R5 is connected to the base of the transistor T3, the emitter of the transistor T3 is grounded, and the collector is connected to the resistor R4, the other end of the resistor R4 is connected to the coil of the relay U14 and the Zener diode D5, the other end of the coil of the relay U14 and the other end of the Zener diode D5 are connected to the first group of normally open points of the relay U14 and the power supply VCC, the other end of the first group of normally open points of the relay U14 is connected to the resistor R3, the other end of the resistor R3 is connected to the diode lamp L1, the other end of the diode lamp L1 is grounded, and the two ends of the second group of normally open points of the relay U14 are connected to the terminals OUT1 and OUT2.

[0011] As a further optional scheme for the switching switch driving circuit used for high-current short-circuit compensation of an electric arc furnace, the fourth pin of the input end of the N555 timer circuit is connected to the contactor output control circuit and the D latch circuit, the third pin of the output end of the N555 timer circuit is connected to the resistor R108, and the other end of the resistor R108 is connected to the transistor amplifier circuit.

[0012] As a further optional scheme for the switching switch driving circuit used for high current short-circuit compensation of the electric arc furnace, the base of the transistor T1 of the transistor amplifier circuit is connected to R108, the emitter of the transistor T1 is grounded, and the collector of the transistor T1 is connected to the forward and reverse thyristor driving circuit.

[0013] As a further optional scheme for the switching switch driving circuit applied to the high-current short-circuit compensation of the ore-fired furnace, one end of the input end of the transformer TS2 and the transformer TS1 of the forward and reverse thyristor driving circuit is connected together to connect the triode amplifier circuit, and the other end of the input end of the transformer TS2 and the transformer TS1 is respectively connected to the resistor R113 and the resistor R112, and the other end of the resistor R113 and the resistor R112 is respectively connected to the first filter circuit and the second filter circuit, and the other end of the first filter circuit and the second filter circuit is connected to the power supply VCC, and the transformer TS2 and the transformer TS1 are respectively connected to the first filter circuit and the second filter circuit. One end of the output end is connected to a diode D2 and a diode D1 respectively, the other ends of the diode D2 and the diode D1 are connected to gate terminals G2 and G1 driven by the thyristor, the other ends of the output ends of the transformer TS2 and the transformer TS1 are connected to cathode terminals K2 and K1 driven by the thyristor, the cathode terminals K2 and K1 are connected to resistor R116 and resistor R115 respectively, the other ends of the resistor R116 and the resistor R115 are connected to diode D3 and diode D4 respectively, the other ends of the diode D3 and the diode D4 are connected to one end of the output end of the transformer TS2 and the transformer TS1 respectively.

[0014] The beneficial effects of the utility model are as follows: by arranging a power supply circuit, a trigger control circuit, a zero-crossing comparison circuit, a D latch circuit, a contactor output control circuit, an N555 timer circuit, a transistor amplifier circuit and a forward and reverse thyristor drive circuit, it can ensure that there is no impact surge current when the thyristor is triggered to input the capacitor through zero crossing, and at the same time, a control signal is output to the contactor, so that the function of long-term current flow is completed by the contactor, and zero-crossing is achieved, while avoiding the huge heat and loss generated when the thyristor is running, and the contactor does not generate arcing, and the service life is enlarged from electrical life to mechanical life, thereby realizing maintenance-free, safe and stable operation of the short-circuit compensation product in the electric arc furnace industry within the full life cycle. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0016] Figure 1 This is a circuit diagram of a switching switch driving circuit used for high current short network compensation of a submerged arc furnace according to the utility model;

[0017] Explanation of the accompanying drawings: 1. Power supply circuit; 2. Trigger control circuit; 3. Zero-crossing comparison circuit; 4. D latch circuit; 5. Contactor output control circuit; 6. N555 timer circuit; 7. Transistor amplifier circuit; 6. N555 timer circuit; 8. Forward and reverse thyristor drive circuit. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] refer to Figure 1A switching switch driving circuit for high current short network compensation of an electric arc furnace includes a power supply circuit 1, a trigger control circuit 2, a zero crossing comparison circuit 3, a D latch circuit 4, a contactor output control circuit 5, an N555 timer circuit 6, a transistor amplifier circuit 7 and a forward and reverse thyristor driving circuit 8. The trigger control circuit 2 and the zero crossing comparison circuit 3 are connected to the D latch circuit 4, the D latch circuit 4 is connected to the N555 timer circuit 6 and the contactor output control circuit 5, the N555 timer circuit 6 is connected to the transistor amplifier circuit 7, and the transistor amplifier circuit 7 is connected to the forward and reverse thyristor driving circuit 8 to output a bidirectional thyristor zero crossing trigger synchronous pulse to control the opening and closing of the bidirectional thyristor.

[0020] In this embodiment, by arranging a power supply circuit 1, a trigger control circuit 2, a zero-crossing comparison circuit 3, a D latch circuit 4, a contactor output control circuit 5, an N555 timer circuit 6, a transistor amplifier circuit 7 and a forward and reverse thyristor drive circuit 8, it can ensure that there is no impact surge current when the thyristor is triggered to input the capacitor through zero crossing, and at the same time, a control signal is output to the contactor, so that the function of long-term current flow is completed by the contactor, and the input zero crossing is realized, and the huge heat and loss generated during the operation of the thyristor are avoided, and the contactor does not generate arcing, and the life span is enlarged from the electrical life to the mechanical life, thereby realizing the maintenance-free, safe and stable operation of the short-circuit compensation product in the electric arc furnace industry throughout the life cycle.

[0021] It should be noted that, through the high-precision zero-crossing comparison circuit combined with the operational amplifier comparison circuit, the zero-crossing accuracy can be made less than 100us, and the terminal voltage of the capacitor is detected and compared with the system voltage. The voltage difference crosses zero, that is, the capacitor is switched on at △U=0. The characteristic of the capacitor is that the current value corresponding to the moment △U=0 is 0, so even if there is voltage when the capacitor is just cut off, it can be guaranteed to be switched on at zero crossing, and it can be switched on at a time interval of 10ms. Moreover, it can be done in the high current environment of the electric arc furnace, due to the design of the filter circuit and the design of anti-electromagnetic interference and anti-false triggering, so that the switch can operate safely and stably.

[0022] In addition, the switching switch is a thyristor flexible switch.

[0023] Preferably, the power supply circuit 1 is connected in parallel with a varistor R0 at the input end of the power transformer TS0, and a rectifier bridge is connected at the output end of the power transformer TS0. The output end of the rectifier bridge is respectively connected in parallel with a capacitor C1, a voltage regulator tube T0, a capacitor C2, a resistor R1, a series light-emitting diode L0, and an adjustable resistor R0.

[0024] Preferably, a resistor R101 is connected in parallel between the trigger terminal K of the trigger control circuit 2 and the power supply VCC, one end of the resistor R101 is connected to the resistor R102, the other end of the resistor R102 is connected to the capacitor C101, the other end of the capacitor C101 is connected to the power supply VCC and the resistor R105, the other end of the resistor R102 is connected to the resistor R103, the other end of the resistor R103 and the other end of the resistor R105 are respectively connected to the transistor T2, and the other end of the resistor R105 is also connected to the D latch circuit 4.

[0025] Preferably, the K1 end and the K2 end of the zero-crossing comparison circuit 3 are respectively connected to the resistor R119 and the resistor R118, the other ends of the resistor R119 and the resistor R118 are respectively connected to the second pin and the fourth pin of the optocoupler U2, the sixth pin of the optocoupler U2 is connected to the resistor R110 and the third pin of the U0 op amp circuit, the other end of the R110 is connected to the power supply VCC, the fourth pin and the eighth pin of the U0 op amp circuit are respectively grounded and the power supply VCC, the first pin of the U0 op amp circuit is connected to the resistor R111 and the D latch circuit, and the other end of the resistor R111 is grounded.

[0026] Preferably, the eighth pin of the D latch circuit 4 is connected to the zero-crossing comparison circuit 3, the thirteenth pin of the D latch circuit 4 is connected to the trigger control circuit 2, the first pin, the ninth pin, and the eleventh pin of the D latch circuit 4 are connected together, the twelfth pin and the thirteenth pin of the D latch circuit 4 are connected together, the sixth pin and the tenth pin of the D latch circuit 4 are connected together, the third pin and the fifth pin of the D latch circuit 4 are connected together, the second pin and the fourth pin of the D latch circuit 4 are connected together, and the second pin of the D latch circuit 4 is connected to the contactor output control circuit 5 and the N555 timer circuit 6.

[0027] Preferably, the resistor R5 of the contactor output control circuit 5 is connected to the D latch circuit 4, the other end of the resistor R5 is connected to the base of the transistor T3, the emitter of the transistor T3 is grounded, and the collector is connected to the resistor R4, the other end of the resistor R4 is connected to the coil of the relay U14 and the Zener diode D5, the other end of the coil of the relay U14 and the other end of the Zener diode D5 are connected to the first group of normally open points of the relay U14 and the power supply VCC, the other end of the first group of normally open points of the relay U14 is connected to the resistor R3, the other end of the resistor R3 is connected to the diode lamp L1, the other end of the diode lamp L1 is grounded, and the two ends of the second group of normally open points of the relay U14 are connected to the terminals OUT1 and OUT2.

[0028] Preferably, the fourth pin of the input end of the N555 timer circuit 6 is connected to the contactor output control circuit 5 and the D latch circuit 4, the third pin of the output end of the N555 timer circuit 6 is connected to the resistor R108, and the other end of the resistor R108 is connected to the transistor amplifier circuit 7.

[0029] Preferably, the base of the transistor T1 of the transistor amplifier circuit 7 is connected to R108 , the emitter of the transistor T1 is grounded, and the collector of the transistor T1 is connected to the forward and reverse thyristor driving circuit 8 .

[0030] Preferably, one end of the input end of the transformer TS2 and the transformer TS1 of the forward and reverse thyristor driving circuit 8 is connected together to connect the triode amplifier circuit 7, the other end of the input end of the transformer TS2 and the transformer TS1 is respectively connected to the resistor R113 and the resistor R112, the other end of the resistor R113 and the resistor R112 is respectively connected to the first filter circuit and the second filter circuit, the other end of the first filter circuit and the second filter circuit is connected to the power supply VCC, one end of the output end of the transformer TS2 and the transformer TS1 is respectively connected to the diode D2 and the diode D1, the other end of the diode D2 and the diode D1 is connected to the gate terminals G2 and G1 of the thyristor drive, the other end of the output end of the transformer TS2 and the transformer TS1 is connected to the cathode terminals K2 and K1 of the thyristor drive, the cathode terminals K2 and K1 are respectively connected to the resistor R116 and the resistor R115, the other end of the resistor R116 and the resistor R115 is respectively connected to the diode D3 and the diode D4, the other end of the diode D3 and the diode D4 is respectively connected to one end of the output end of the transformer TS2 and the transformer TS1.

[0031] The specific working principle is as follows:

[0032] (1) Input 220V AC signal from L and N terminals;

[0033] (2) Wiring of terminals G1, K1, G2, and K2: G1 is connected to the gate of the forward thyristor, K1 is connected to the cathode of the forward thyristor, G2 is connected to the gate of the reverse thyristor, and K1 is connected to the cathode of the reverse thyristor. Connect the thyristor switch and contactor switch in parallel and connect the capacitor load. Measure the current waveform of the capacitor and adjust the resistance with zero-crossing precision until there is no current surge when the capacitor is plugged in.

[0034] (3) Wiring of terminals OUT1 and OUT2: These terminals are the normally open contacts of the relay, which send signals to the contactor to close and open, allowing the thyristor to pass zero and input the load, and then the contactor can conduct current for a long time.

[0035] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A switching switch driving circuit used for high current short-circuit compensation of an electric arc furnace, characterized in that: The invention comprises a power supply circuit (1), a trigger control circuit (2), a zero-crossing comparison circuit (3), a D latch circuit (4), a contactor output control circuit (5), an N555 timer circuit (6), a triode amplifier circuit (7) and a forward and reverse thyristor drive circuit (8), wherein the trigger control circuit (2) and the zero-crossing comparison circuit (3) are connected to the D latch circuit (4), the D latch circuit (4) is connected to the N555 timer circuit (6) and the contactor output control circuit (5), the N555 timer circuit (6) is connected to the triode amplifier circuit (7), and the triode amplifier circuit (7) is connected to the forward and reverse thyristor drive circuit (8) to output a bidirectional thyristor zero-crossing trigger synchronous pulse to control the opening and closing of the bidirectional thyristor.

2. A switching switch driving circuit for high current short-circuit compensation of a submerged arc furnace according to claim 1, characterized in that: The power supply circuit (1) has a varistor R0 connected in parallel at the input end of the power transformer TS0, and a rectifier bridge connected at the output end of the power transformer TS0; the output end of the rectifier bridge is respectively connected in parallel with a capacitor C1, a voltage regulator tube T0, a capacitor C2, a resistor R1, a light-emitting diode L0, and an adjustable resistor R0.

3. The switching switch driving circuit for high current short-circuit compensation of an ore-fired furnace according to claim 1 is characterized in that: A resistor R101 is connected in parallel between the trigger terminal K of the trigger control circuit (2) and the power supply VCC, one end of the resistor R101 is connected to a resistor R102, the other end of the resistor R102 is connected to a capacitor C101, the other end of the capacitor C101 is connected to the power supply VCC and a resistor R105, the other end of the resistor R102 is connected to a resistor R103, the other end of the resistor R103 and the other end of the resistor R105 are respectively connected to a transistor T2, and the other end of the resistor R105 is simultaneously connected to a D latch circuit (4).

4. The switching switch driving circuit for high current short-circuit compensation of a submerged arc furnace according to claim 1 is characterized in that: The K1 end and the K2 end of the zero-crossing comparison circuit (3) are connected to a resistor R119 and a resistor R118 respectively, the other ends of the resistor R119 and the resistor R118 are connected to the second pin and the fourth pin of the optical coupler U2 respectively, the sixth pin of the optical coupler U2 is connected to a resistor R110 and the third pin of the U0 operational amplifier circuit, the other end of the R110 is connected to a power supply VCC, the fourth pin and the eighth pin of the U0 operational amplifier circuit are connected to the ground and the power supply VCC respectively, the first pin of the U0 operational amplifier circuit is connected to a resistor R111 and a D latch circuit, and the other end of the resistor R111 is grounded.

5. The switching switch driving circuit for high current short-circuit compensation of a submerged arc furnace according to claim 1, characterized in that: The eighth pin of the D latch circuit (4) is connected to the zero-crossing comparison circuit (3), the thirteenth pin of the D latch circuit (4) is connected to the trigger control circuit (2), the first pin, the ninth pin and the eleventh pin of the D latch circuit (4) are connected together, the twelfth pin and the thirteenth pin of the D latch circuit (4) are connected together, the sixth pin and the tenth pin of the D latch circuit (4) are connected together, the third pin and the fifth pin of the D latch circuit (4) are connected together, the second pin and the fourth pin of the D latch circuit (4) are connected together, and the second pin of the D latch circuit (4) is connected to the contactor output control circuit (5) and the N555 timer circuit (6).

6. The switching switch driving circuit for high current short-circuit compensation of a submerged arc furnace according to claim 1, characterized in that: The resistor R5 of the contactor output control circuit (5) is connected to the D latch circuit (4), the other end of the resistor R5 is connected to the base of the transistor T3, the emitter of the transistor T3 is grounded, and the collector is connected to the resistor R4, the other end of the resistor R4 is connected to the coil of the relay U14 and the voltage-stabilizing diode D5, the other end of the coil of the relay U14 and the other end of the voltage-stabilizing diode D5 are connected to the first group of normally open points of the relay U14 and the power supply VCC, the other end of the first group of normally open points of the relay U14 is connected to the resistor R3, the other end of the resistor R3 is connected to the diode lamp L1, the other end of the diode lamp L1 is grounded, and the two ends of the second group of normally open points of the relay U14 are connected to the terminals OUT1 and OUT2.

7. The switching switch driving circuit for high current short-circuit compensation of a submerged arc furnace according to claim 1, characterized in that: The fourth pin of the input end of the N555 timer circuit (6) is connected to the contactor output control circuit (5) and the D latch circuit (4), the third pin of the output end of the N555 timer circuit (6) is connected to the resistor R108, and the other end of the resistor R108 is connected to the transistor amplifier circuit (7).

8. The switching switch driving circuit for high current short-circuit compensation of a submerged arc furnace according to claim 1, characterized in that: The base of the transistor T1 of the transistor amplifier circuit (7) is connected to R108, the emitter of the transistor T1 is grounded, and the collector of the transistor T1 is connected to the forward and reverse thyristor drive circuit (8).

9. The switching switch driving circuit for high current short-circuit compensation of a submerged arc furnace according to claim 1, characterized in that: One end of the input end of the transformer TS2 and the transformer TS1 of the forward and reverse thyristor drive circuit (8) is connected together to connect to the triode amplifier circuit (7); the other end of the input end of the transformer TS2 and the transformer TS1 is connected to the resistor R113 and the resistor R112 respectively; the other end of the resistor R113 and the resistor R112 is connected to the first filter circuit and the second filter circuit respectively; the other end of the first filter circuit and the second filter circuit is connected to the power supply VCC; one end of the output end of the transformer TS2 and the transformer TS1 is connected to the diode D2 and the diode D1 respectively; the other end of the diode D2 and the diode D1 is connected to the gate terminals G2 and G1 of the thyristor drive; the other end of the output end of the transformer TS2 and the transformer TS1 is connected to the cathode terminals K2 and K1 of the thyristor drive; the cathode terminals K2 and K1 are connected to the resistor R116 and the resistor R115 respectively; the other end of the resistor R116 and the resistor R115 is connected to the diode D3 and the diode D4 respectively; the other end of the diode D3 and the diode D4 is connected to one end of the output end of the transformer TS2 and the transformer TS1 respectively.

Images