KCZ6.5 type three-phase full control (half control) bridge thyristor phase adaptive trigger board


I. Overview

   KCZ6.5 type three-phase fully-controlled (half-controlled) bridge thyristor phase adaptive trigger board is a high-performance power electronic technology product developed by the application of large-scale integrated circuits and digital phase lock technology. It uses the intelligent large-scale integrated circuit chip CA6100 as the core unit and is made with high-quality electronic components. Compared with the conventional three-phase thyristor trigger circuit, it has the following advantages:

  1. There is no need to determine the phase of the three-phase voltage during use. No matter how the user accesses the phase of the three-phase power supply, the output trigger pulse corresponds to the phase of the triggered thyristor one-to-one;

  2. There is no need for external synchronization transformer and power transformer in use;

  3. The board contains a pulse transformer, which can be directly used to trigger 6 thyristors with a capacity below 1650A;

  4. Flat installation, no special plug-in box is required, all connectors are imported high-quality plug-ins, so the contact is very reliable.

Second, the internal structure of KCZ6.5 general-purpose thyristor trigger board

  The trigger board is mainly composed of the following parts:

   phase reference (reference) circuit, buffer amplifier and soft start/soft stop circuit, phase locked loop, phase loss detection and prohibition circuit, phase sequence detection and selection switch, monitoring circuit, pulse amplifier and pulse Transformers, etc.

Three, practical application

  1. Two-quadrant bridge converter


Figure 1  Two-quadrant bridge converter

    Trigger board configuration:              Application:

    a.30<phase reference             a. Power supply
    b.2゛30<pulse             b. DC motor drive
    c.3.5<゛130<Door extension angle range 
    d. The phase reference comes from the SCR cathode

              
Figure 2 is the principle diagram of voltage stabilization and current limiting control. Vd is the voltage setting, Id is the current limiting value setting, and Vf and If are the voltage and current feedback signals.

                 Figure 2  Stabilized current limiting control circuit

   Figure 3 shows the soft start-stop control circuit, the potentiometer is a given potentiometer, such as the voltage given potentiometer in Figure 2; I2 is the KCZ6.5 trigger board Soft stop control terminal, when it is low level, the trigger board starts to soft stop, and the trigger pulse delay angle slides from the original value to the maximum value at a certain speed; when it is in the floating state, the trigger board starts softly, and the trigger pulse moves just the opposite. When it reaches the SS (soft start) side, the voltage at the Vdh end of the potentiometer rises according to a certain slope, and the soft start ends when it reaches the set value. When the switch is switched to the S (soft stop) side, the voltage at the Vdh terminal will decrease according to a certain slope until it reaches zero and the soft stop ends.

< /td>

                  Figure 3  Soft start-stop control circuit

2. AC controller

The circuit principle of    is shown in Figure 4. By changing the gate delay angle of the thyristor, the load can obtain a three-phase AC voltage with variable amplitude. And through the additional voltage or current regulator board to form a closed loop, stable control can be achieved.
  Using this circuit and additional regulators, it has successfully developed a current-limiting starting and energy-saving control system for asynchronous motors.
   If the load is a three-phase symmetrical resistance load, such as a resistance heating furnace, the temperature control of the load can be realized.



Figure 4

   trigger board configuration:              Application:
  A.0<phase reference              a. AC side control    
  B. 120< pulse               b. Reduced voltage start of three-phase asynchronous motor
  C. 5<゛175<Door extension angle range       c. Resistance heating furnace
  D. The phase reference comes from the SCR cathode

IV. Installation instructions

  1. Remove the packaging bag, take out the trigger board, AMP plug-in, pins and other parts.

  2. According to the designed method of use, select the necessary plug positions for J1゛J4, and connect the 16゛20 multi-core flexible wires of appropriate length to the AMP plug-in unit after welding or crimping or a special crimping tool. The corresponding positions of the department are seated.

  3. According to the standard circuit connection diagram, connect the twelve wires of J1 and J2 corresponding to 6 SCRs with the gate and cathode of the SCR. The length of the wires should not exceed 50 cm. Each pair of wires (the gate of the same SCR) And the cathode) should be twisted, at least one twist per 2.5 cm. This can reduce the interference of high-frequency clutter in high-power applications. Generally, the leads of the three SCR cathodes -A, -B, and -C also introduce synchronization signals. Therefore, the twelve wires must correspond to each other and cannot be connected wrongly.

  J3 is used to connect with other control circuits, and its SIG terminal is generally used. This terminal is fed with a DC control voltage of 0゛5V, which can make the SCR conduction angle from the smallest to The biggest change. I2 terminal, when this terminal is shorted to ground, a soft stop is generated. I1 terminal, this terminal will generate a quick stop (blocking pulse) after opening a circuit with 12V. In addition, there are +12V terminal, COM terminal and so on. Please refer to the circuit in Figure 1 above.

  J4 is the input socket of 220V AC power (or 380V) when a power transformer is installed on the circuit board. Please confirm whether the voltage corresponds to the voltage used by the transformer.

  4. The mounting hole size of the standard KCZ6.5 board is shown in Figure 5. In the figure, sockets J1A, J2A, and J3A are sockets used to replace the three sockets J1, J2, and J3 on the KCZ6.5 board respectively on the KCZ6.5 board.

  5. Please check carefully according to the diagram, whether the wiring corresponds to the use diagram one-to-one, wrong connection may cause damage to the circuit board or components, if you have any questions, please call.

   6. When the SCR is not connected to the three-phase power supply, switch on the AC voltage at the terminals and on J4 or J3 to get AC 220V or 24V power on the board. The three LEDs on the board, the power indicator (green), the lack of phase indicator (red), and the prohibition indicator (red), should light up.

  7. Confirm that the given voltage (SIG terminal of connector J3) is zero, and turn on the three-phase voltage. Note that the three-phase voltage should be given the rated value at one time, and the error should not exceed \20% of the rated voltage. Don't use a voltage regulator to slowly go up, at this time, the two red LEDs should go out.

   8. Gradually increase the given voltage, and the SCR output (monitored by a voltmeter or oscilloscope) will also change correctly, and the installation will be initially completed.

  9. For non-standard circuit applications, such as when the primary side of the transformer or the synchronization transformer provides synchronization, the gates of each SCR should be disconnected first, and the anode of each SCR and the corresponding pulse phase and phase sequence should be checked with an oscilloscope. The gate can be connected only after confirming that it is correct.

  10. The only adjustable programmable switch PP1 on the trigger board is used to determine the required trigger pulse. When 1, 2, 3 minutes (OFF), 4, 5, and 6 are closed (ON), the pulse reference phase is 0<, otherwise it is 30<. When 7 points and 8 points are on, the trigger pulse is 120< wide. When both 7, 8 are combined, the pulse width is adjustable from 2 to 30<. Both 7 and 8 time-sharing are double narrow pulses (interval 60<).

             Figure 5   Schematic diagram of the sockets and positions of the KCZ6.5 thyristor trigger board