KCZ6MF-1 digital thyristor closed-loop control board for DC electric arc furnace

 

KCZ6MF-1 digital thyristor closed-loop control board for DC electric arc furnace is a fully digital thyristor closed-loop trigger control board developed by our companys unique KC-198 ASIC chip. It With digital control, the output pulse symmetry is good, the synchronous transformer can be used or not, and it has excellent performance such as self-phase function. It is based on the KCZ6SM-3 digital closed-loop thyristor trigger control board with protection function A control board developed by adding many special requirements of DC electric arc furnace technology. This control board can be used in the DC electric arc furnace power control system, and can also be used to replace the KCZ6.2, KCZ6-1T, and JQC3.1 types originally produced by our company. The three-phase thyristor full-bridge control board is used in three-phase controllable rectification and three-phase AC voltage regulation systems.

I. Main technical parameters and design features

1. Direct 380V power supply, the board contains +15V, +5V, +24V power generation links required for its own work.

2. It has the functions of phase loss, external fault (such as cooling water system fault), undervoltage of its own working power supply, overvoltage and overcurrent protection of the controlled system.

3. The board contains a pulse amplification link and a given integral function, as well as a closed-loop regulator, the output can directly trigger six 51650A/1003500V thyristors.

4. There are 7 potentiometers in the board, which are used to adjust the threshold of overvoltage and overcurrent protection and the size of the closed-loop feedback coefficient, as well as the maximum and minimum angles of phase shift triggering, so that the control performance is more optimized and ideal.

5. The current cut-off threshold varies with the given value during tracking, so as to optimally meet the needs of different current values ??under different operating conditions such as arc starting, catching, smelting, etc. of the DC electric arc furnace, thus making arc starting easier and arc voltage Stable and guarantee continuous arc.

II. Normal working conditions

The digital thyristor closed-loop control board for KCZ6MF-1 DC electric arc furnace can work normally under the following conditions:

1. The altitude does not exceed 1500m;

2. The operating environment temperature is -1045;

3. The relative humidity of the air is 90% (when the relative ambient temperature is 20);

4. There is no conductive, explosive dust, no corrosive and insulating gas around;

5. No severe vibration and shock.

Three, user instructions and wiring method

3.1 Notice to users

1. The KC-198 special control chip in the digital thyristor closed-loop control board for KCZ6MF-1 DC electric arc furnace is a programmable logic controller produced in the United States, and the intelligent software compiled by our company is written in it, because the integrated circuit is a CMOS device , So be careful to prevent breakdown damage caused by static electricity during use, so you must not directly touch the pins of the KC-198 integrated circuit with your hands, and do not use a multimeter to measure the pins of the integrated circuit.

2. The digital thyristor closed-loop control board for KCZ6MF-1 DC electric arc furnace adopts plane installation, and the installation aperture is 4-4.5.

4. When installing the digital thyristor closed-loop control board for KCZ6MF-1 DC electric arc furnace, the distance between the back and the conductive mounting board should be greater than 20mm, and there should be space for unplugging the plug-in unit at the top, bottom and left of the mounting position. There should be no heat within 200mm below the board. Large device.

5. The connecting wire area should be a soft wire of 0.5mm2 or more. The feedback protection signal, the given potentiometer and the pulse output wire should be twisted-pair wires, and no less than 8~10 twists per 100mm. From the output of the control board G1, K1~ The leads between G6, K6 and the cathode of the triggered six-way thyristor gate should be as short as possible, and twisted pair or coaxial cable shielded wire should be used as much as possible.

6. The standard use of KCZ6MF-1 digital thyristor closed-loop control board for DC electric arc furnace is to directly use the working system without a synchronous transformer. The line voltage is 660V (standard products are ordered according to the current limiting resistance of 380V welding at the factory, higher than 660V or lower than 380V. In the system, when the working voltage of the user's system is higher than 660V or the voltage is very low (less than 10V), it is recommended to use a synchronous transformer. The secondary side line voltage of the synchronous transformer is 380V. The synchronous voltage is the same regardless of whether the synchronous transformer is used or not. Connect according to the following method: the synchronous voltage of the arm corresponding to G1, K1; G4, K4 pulses is connected to the TA in the CN4 socket of the KCZ6MF-1 control board, and the synchronous voltage of the arm corresponding to G3, K3; G6, K6 pulses Connect the TB in the CN4 socket of the KCZ6MF-1 control board, and the synchronous voltage of the arm corresponding to the G2, K2, G5, K5 pulses connects to the TC in the CN4 socket of the KCZ6MF-1 control board. In this case, mark the board with Points 1 and 3 of A, B, and C are disconnected, and 1 and 2 can be short-connected.

3.2 Correct wiring

KCZ6MF-1 digital thyristor closed-loop control board for DC electric arc furnace leads to a total of 13 connectors. The external wiring method of each connector is as follows:

1. The pins 1 (+24V) and 2 (Xi, i=16) of the connectors N6, N1, N4, N5, N2, N3 are connected to the pulse final board or the pulse transformer corresponding to the triggered six channels The gate cathodes of the thyristor G1, K1; G2, K2; G3, K3; G4, K4; G5, K5; G6, K6 input terminals +24V and gi (i=1~6).

2. Pin 1 and pin 2 of the connector CN3 are connected to a 380V power supply.

3. Pin 1 (-15V), pin 2 (GND), and pin 3 (+15V) in the connector CN5 are two positive and negative power supplies for users. The power supply allows a load capacity of 20mA.

4. Pin 3 (P), pin 2 (Ug), and pin 1 (GND) of connector CN9 are directly connected to a given potentiometer (the resistance of the given potentiometer is greater than 4.7k, and the power should be greater than 0.5W). Pin 3 and pin 1 are connected to the fixed end of the potentiometer, and pin 2 is connected to the sliding end of the potentiometer.

5. Connect an external fault protection contact between pin 3 (WPL) and pin 2 (GND) of the CN8 connector (disconnected in the event of a fault), which is used to protect against external faults (such as cooling System failure), when this protection function is not used, this function can be deleted by shorting the two ends. The reset button is connected between pin 1 (RST) and pin 2 (GND) of CN8, which is used to reset the protection (Short the two points to reset).

6. Pin 1 (JD-CB), pin 2 (JD-Z), and pin 3 (JD-CK)) in the connector CN1 are the three leading terminals of the integrated protection relay, and pin 2 is the common terminal. There is a normally closed contact between pin 1 and pin 2, and a normally open contact between pin 2 and pin 3, the contact capacity is 220V/1A or 380V/0.5A, any of the three pins The protection or alarm circuit is connected to the contact point as the action contact point for breaking the user's main circuit.

6. When the user system voltage sampling is AC sampling, then pins 3 to 5 of the connector CN7 are connected to the output of the user system voltage sampling link; at this time, pin 1 (F2-1) and pin 2 (F2-2) Floating, if the user system voltage sampling is DC, then the voltage sampling value is connected to pin 1 and pin 2 (pin 1 is the positive terminal), at this time pins 3 to 5 are floating; the voltage sampling in use can also be AC It can be DC sampling, the amplitude is 010V/0.1A.

7. If AC sampling is used for current sampling of the user system, pins 3 to 5 of the connector CN6 are connected to the output of the current sampling link of the user system. At this time, pins 1 and 2 are left floating. If the current sampling value of the user system is DC (for example, when sampling by a Hall current sensor), then pin 1 (F1-1) of the connector CN6 is connected to the positive end of the sampling, and pin 2 (F1-2) is connected to the sampling At this time, pins 3 to 5 are floating. In use, the current sampling can be AC ??or DC. The sampling input should be a signal that converts the current signal into a voltage, with an amplitude of 0-10V/0.1A.

3.3 Function and adjustment method of potentiometer

There are 7 potentiometers in the digital thyristor closed-loop control board for KCZ6MF-1 DC electric arc furnace. The functions and adjustment methods of each potentiometer are as follows:

1. Potentiometer RP3 is used to adjust the actual equivalent sampling value of the physical quantity corresponding to the closed-loop control-voltage (or current). Adjust the sampling value clockwise to increase (equivalent to a decrease in the protection threshold), and adjust the sampling value counterclockwise to decrease (equivalent to As the protection threshold is raised).

2. The potentiometer RP2 is the adjustment potentiometer when the output is set to a given number of times. The magnification is adjusted clockwise to increase, and the magnification is adjusted counterclockwise to decrease.

3. Potentiometer RP4 is a physical quantity that does not form a closed loop-the actual sampling value adjustment potentiometer of current (or voltage). Adjust the sampling value clockwise to increase (equivalent to lower protection threshold), and adjust the sampling value counterclockwise to decrease (equivalent to increase protection threshold) ).

4. Potentiometer RP10 is a given minimum trigger control angle ?Cmin adjustment potentiometer, clockwise adjustment ?Cmin increases, counterclockwise adjustment ?Cmin Decrease.

5. When the potentiometer RP9 is set to zero, the maximum trigger control angle ?Cmax adjusts the potentiometer, clockwise adjusts ?Cmax increases, counterclockwise adjusts ?Cmax Decrease.

6. The potentiometer RP1 sets the integral rise time to adjust the potentiometer, clockwise adjusts the set integral time to become longer, and counterclockwise adjusts the set integral time to decrease.

7. The potentiometer RP7 is a regulator type equivalent magnification adjustment potentiometer. It is adjusted clockwise to increase the equivalent magnification and counterclockwise to decrease the equivalent magnification.

3.4 Other issues that should be explained

Connector CN6 corresponds to the feedback input channel that forms a closed loop, so what amount of closed loop needs to be formed, then connect the sample value of that amount to this channel, if you want to form a current closed loop, this channel is connected to the current sample value. The CN7 channel is connected to the voltage sampling value; if a voltage closed loop is formed, the channel is connected to the voltage sampling value, and the CN7 channel is connected to the current sampling value.

3.5 Parameter restrictions

The input and output load capacity of the digital thyristor closed-loop control board for the KCZ6MF-1 DC electric arc furnace is:

1. Input parameters:

(1) The power supply is 380V, and the maximum load current is 0.1A.

(2) The maximum range of sampling value input by CN7 socket is 010V/0.1A.

(3) The maximum range of sampling value input from CN6 socket is 010V/0.1A.

(4) The synchronous input voltage range of TA, TC, TB is 30V380V/0.1A (this can be achieved by adjusting the current limiting resistors R1, R2, R3).

2. Output parameters

(1) CN5 corresponds to +15V, -15V power supply with a maximum load capacity of 20mA.

(2) The maximum pulse load current of +24V, X1+24V, X2 is 150mA, and the maximum no-load voltage amplitude is +24V.

(3) Six groups of thyristors with a capacity in the range of 51650A/1002500V can be triggered by the matching of the pulse final stage unit.