JQC3.1 type thyristor three-phase half-control trigger control board


I. Overview

The JQC3.1 type thyristor three-phase half-control trigger control board is designed for the control of the thyristor trigger board in the power electronic complete set of power electronic devices whose main circuit is three-phase half-wave or three-phase bridge-type half-control circuit topology, so it can It is widely used in the fields of DC speed regulation, three-phase AC voltage regulation, DC power supply and other fields of the above-mentioned circuit structure. Compared with the KCZB trigger board, it eliminates the three-phase lack of phase and misphase protection, so the overall size is smaller than that of the KCZB board. The structure is more compact.

II. Main technical indicators

1. The input working voltage is three-way three-phase AC, the phase voltages are 8V, 9V and 14゛30V, 50Hz;
2. The board contains a given integration link, and the given integration time can be adjusted from 0 to 30 seconds;
  3. The board contains over-voltage (over-current) and under-voltage (under-current) protections. When performing over-voltage and under-voltage protection, it is a stable current system. When performing over-current and under-current protection, it is a voltage stabilizing system. The steady flow can be selected by the user with a code switch in the board, so it has great flexibility;
  4. The imported TCA785 is used as the trigger pulse to form the chip, so the reliability is improved;
   5. The working power supply in the board is formed by a three-phase AC incoming line, so when one phase of the power grid is out of power, it will not cause the control board to change pulses, and the anti-interference ability is stronger;
   6. The board contains a pulse blocking unit to ensure that the main contactor in the main circuit is closed and opened at zero current when starting or stopping, which not only prolongs the life of the contactor but also avoids the impact of the user system;
  7. The output can directly drive three thyristors with a capacity below 1650A, making the user system wiring more convenient;
8. With the function of self-resetting after protection, the time from protection to self-resetting is adjustable;
9. The overall dimensions are: length〜width〜height=220mm〜217mm〜38mm;
  10. The installation size and hole distance are: length〜width=200mm〜200mm, four holes φ4.3.

3. How to use
   JQC3.1 type board component layout as shown in Figure 1. It can be seen from the figure that there are 6 connectors in the board that are connected to the outside, 17 potentiometers and 1 output selection switch IC7.


Figure 1 Schematic diagram of the layout of JQC-3.1 control board components (click on the above figure to enlarge)


The functions and functions of each potentiometer are as follows:
1. The potentiometer P1 is a potentiometer for adjusting the given integral time. It adjusts the given integral time clockwise to make it shorter, and adjusts the given integral time counterclockwise to make it longer. The effect of the given integral is to realize that the change from the output from 0V to the maximum value set by the user system when the user suddenly adds the given value is a ramp function, so as to avoid the impact of the user system.
2. The potentiometer P5 is the adjustment potentiometer that the differential device outputs the lowest voltage when the output adjustment potentiometer on the user panel is at the maximum setting. The lowest voltage corresponds to the highest output voltage of the thyristor power supply in the user system, and the highest output voltage of the power supply can be limited with the different adjustment positions of P5.
  3. P16, P17, P18 are three-phase synchronous voltage balance adjustment potentiometers. The function of these three potentiometers is also reflected in adjusting the RC filter time constant of the synchronous voltage, that is, adjusting the delay angle of the synchronous voltage relative to the main circuit is the thyristor anode and cathode voltage. , Clockwise adjust the equivalent synchronization voltage added to the TCA785 pin 5# front current-limiting resistor to increase, that is, the RC filter time constant is reduced, and counterclockwise adjust the equivalent synchronization added to the pin 5# front current-limiting resistor The voltage decreases, that is, the RC filter time constant increases.
  4. The potentiometer P4 is the current cut-off protection threshold adjustment potentiometer, the current cut-off protection threshold is adjusted clockwise to decrease, and the current cut-off protection threshold is adjusted counterclockwise to increase.
   5. P3 is the second-level threshold adjustment potentiometer for undervoltage (undercurrent) protection. Once the potentiometer is adjusted, it does not need to be adjusted.
   6. P9 is the over-voltage (over-current) protection action threshold adjustment potentiometer. The protection action threshold is adjusted clockwise to increase, and the protection threshold is adjusted counterclockwise to decrease.
  7. P13 is the undervoltage (undercurrent) protection action threshold adjustment potentiometer. The protection action threshold is adjusted clockwise to increase, and the protection threshold is adjusted counterclockwise to decrease.
8. When the P2 potentiometer is at the given minimum, the output of the differentiator is added to the maximum value of the phase shift voltage adjustment potentiometer of TCA785 pin 11#. Adjust the limit value clockwise to increase, and adjust the limit value counterclockwise to decrease, that is The DC voltage output by the load terminal decreases when the potentiometer is adjusted clockwise, and increases when the potentiometer is adjusted counterclockwise.
9. Potentiometer P7 is a potentiometer that adjusts the output voltage or current amplitude. Clockwise adjusts the output voltage of the user system to increase, and counterclockwise adjusts the output voltage to decrease.
  10. Potentiometers P10, P11, and P12 correspond to the three-phase synchronous sawtooth wave amplitude adjustment potentiometers of a, b, and c, respectively. Clockwise adjustment corresponds to an increase in the amplitude of the sawtooth wave, and an anticlockwise adjustment to decrease the amplitude of the sawtooth wave. The three potentiometers have been adjusted before leaving the factory, and generally do not need to be adjusted again
  11. The potentiometers P8, P6, and P14 correspond to the fine-tuning potentiometers of the highest voltage on the three potentiometers of over-gate (overvoltage or overcurrent) and under-gate (undervoltage or undercurrent) and output adjustment. Clockwise adjustment is added to the three potentiometers. The voltage on the three potentiometers decreases, and the voltage applied to the three potentiometers is adjusted counterclockwise to increase.
  12. When the four-position switch SW1 is in use, the left position is always up, and the third position from left to right is up. When the remaining positions are down, it is the output steady current working mode when the rated output voltage is higher; and The fourth position from left to right is dialed upwards and the remaining positions are dialed downwards, which corresponds to the steady current working mode when the rated output voltage is lower. Under these two conditions, the protection links are both over-voltage and under-voltage protection.
The external wiring method of each connector;
1. G1, K1; G3, K3; G5, K5 in the connector S1 are respectively connected to the gate and cathode of the thyristor corresponding to the three-phase power grid A, B, and C in the main circuit.
2. The a, b, c, 300 in the connector S6 are respectively connected to the three-phase synchronous power transformer. The secondary side of the transformer is star connection and corresponds to the three-phase synchronous voltage of the three-phase grid A, B, C and the neutral of the star winding At this point, the synchronization voltage can be 6゛30V (phase voltage).
  3. The +15V, -15V, 300, HLI in the connector S4 are connected to the positive power supply, negative power supply, reference ground and sampling output terminal of the Hall current sensor when the user system uses the Hall current sensor to detect the current signal. And HLV1, +15V, -15V, 300 and HLV2, +15V, -15V, 300 are respectively connected to the sampling output terminal M, positive power supply, negative power supply and reference ground of the Hall voltage sensor. When the output voltage of the user system has a small variation range, it can be connected to either HLV1 or HLV2; when the output voltage of the user control system changes in a large range, to ensure that the setting remains unchanged, the two channels HLV1 and HLV2 can be used to correspond to different The main circuit output has the same feedback voltage value (HLV1 and HLV2 can also be obtained directly from the output of the controlled system by means of resistor divider. HLI can also be obtained by amplifying the millivolt signal taken out by the shunt, requiring HLV1, HLV2 and The value range of HLI is 0゛10V DC).
  4. The 300# in the connector S3 is the reference ground of the control board. Between 305# and 300#, a normally closed contact of the main contactor is connected. Its function is to prevent under-current (or under-voltage) protection in the board during startup. Misoperation. A normally open contact can be connected between 307# and 308# for manual reset after protection. Since there is reset in the JQC3.1 board, 307# and 308# are generally left unconnected. When the user requires manual reset, it is not necessary When the board is automatically reset, the R18 in the board can be removed and a normally open button is connected between 307# and 308#.
In S3, P and 309 are generally connected to a normally closed contact that acts synchronously with the main contactor of the user system. Its function is to ensure that the system is started every time the equivalent setting is zero, and to avoid the set potential The impact of starting when the Ug is not turned to zero will damage the thyristor. This requirement is extremely important when the load is a capacitive load. It also brings the user no need to turn a given potentiometer to In situ to ensure that the output current rises slowly from zero.
  The user start button (normally open contact) is generally connected between L and 300 in the connector S3, so that the main contactor will be closed at zero current every time it starts or stops. The remaining Ug, 300 and P*1 in the connector S3 are connected to the user given potentiometer, Ug is connected to the midpoint of the given potentiometer, and 300 and P*1 are connected to the two fixed ends of the potentiometer.
When the user uses the threshold setting potentiometers P10 and P1 in the board to set the threshold of over-gate (overvoltage or overcurrent) and under-gate (undervoltage or undercurrent), LVG and OVG are the under-gate and over-gate setting values ??respectively , Can be connected to the indicating instrument or suspended. When the user needs to put the threshold setting potentiometer on the cabinet door and not the threshold setting potentiometer in the board, please remove the potentiometers P10 and P1 in the board. At this time, LVG and OVG are respectively connected to the P* in the connector S1 2. P*3 and 300# are connected to the under-door setting potentiometer on the door of the user cabinet (LVG is connected to the middle head of the potentiometer, P*2 and 300# are connected to the two fixed heads) and the over-door setting potentiometer (OVG is connected to the potentiometer) The middle head, P*3 and 300# are connected to two fixed heads). The resistance value of the external given potentiometer and threshold setting potentiometer should not be less than 4.7kΩ, and the power should not be less than 1W. Figure 2 shows the wiring diagram of the JQC-3.1 control board used in the three-phase half-wave controllable rectifier circuit, and Figure 3 shows the schematic diagram of the JQC-3.1 type thyristor trigger control board used in the three-phase half-controlled voltage regulation system .


 Figure 2 JQC-3.1 type thyristor trigger control board used in three-phase half-wave rectification system schematic diagram

        Figure 3 JQC-3.1 type thyristor trigger control board used in three-phase half-controlled AC voltage regulation system schematic diagram