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Automatic Battery Charger with SCR phase angle output

Home Forums Flowcode Project Discussions Automatic Battery Charger with SCR phase angle output

This topic contains 9 replies, has 2 voices, and was last updated by  nestbulala 2 months, 2 weeks ago.

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  • #3303

    nestbulala
    Participant

    Dear Sir,

    I am doing a project on Automatic Battery Charger with SCR Phase Angle output and I get stucked because of lack of libraries to use. Would you be so kind to help me on how to replace the PWM output to Phase Angle output to fire an SCR? Is there a library available to use? I need also to replace the keypad matrix to three buttons up/down, set to reduce the pins IO.

  • #3304

    nestbulala
    Participant

    Automatic Battery Charger zip file

  • #3305

    nestbulala
    Participant

    What file format is allowed to upload a flowcode program?

  • #3306

    nestbulala
    Participant

    Winrar Zip Archive

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  • #3308

    Bitahwa Bindu
    Keymaster

    Hi. Please describe in few lines how your code should work or at least with a circuit diagram as well and how it’s working at the moment and what you require. I can see your Flowcode project, it’s quite big to go through everything and try to understand what you are trying to achieve without prior explanation.

    I can try to help you with the section of code that is not working.

    It’s easy to use push buttons with flowcode, we have tutorials covering that, What problem are you facing in this regard?

    You can’t replace a PWM directly with a “phase angle” to fire the SCR, because these two things operate in different ways, your code must be changed and I don’t know how is your hardware setup.  The SCR will only need a pulse to trigger it.

  • #3309

    nestbulala
    Participant

    Hi Bitahwa,

    Thank you very much for your reply. I have already figured out the buttons. I need only to replace the PWM with phase angle output. At what frequency and how many microseconds delay to trigger the SCR. Do I need to create interrupt to fire at zero crossing or used a hardware like optocoupler MOC with zero crossing.

  • #3310

    nestbulala
    Participant

    Hi Bitahwa,

    This is the schematic of the phase angle control. I maybe using a different PIC but the concept will be the same.

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  • #3312

    Bitahwa Bindu
    Keymaster

    You still haven’t answered all the questions. How is your system supposed to work before writing the code.

    With phase angle controller, the firing pulse is delayed to turn on the SCR in the middle of every half cycle, every time a part of an AC cycle is cut, the power to the load also gets cut. To deliver more or less power to the load, the phase angle is increased or decreased, thereby controlling the throughput power.

    There are several ways to control the firing angle of SCR. Which method are you using?

    You can use a zero-crossing detector circuit to interrupt the microcontroller after every 10 ms. This interrupt commands the microcontroller to generate some delay (in the range of 1ms to 9 ms). The user can increase or decrease the delay in intervals of 1 ms using push buttons. the SCR is then fired through the opto-coupler.  Then you’ll need to create a zero crossing detector and feed the output to an external interrupt pin of the microcontroller to detect each zero crossing.

    Then the microcontroller will will fire the scr with some delays (angle) based on your push buttons values.

    I don’t think this is how your circuit works or maybe it should work in a different way and you are not explaining how.

  • #3313

    nestbulala
    Participant

    The project should work as follows:

    1. The project should charge a banks of batteries in automatic mode
    2. The microcontroller should monitor the battery voltage and current
    3. The setpoints should be set by push buttons increase or decrease
    4. The setpoints should be saved in the eeprom in case of power failure
    5. The battery voltage and current should be shown in the LCD
    6. The SCR should be fired as phase angle principle
    7. Zero crossing will be detected by the microcontroller and create interrupt
    8. In case the batteries are flat, the output current should be at maximum
    9. The SCR should be slowly changing its output as the setting is reached
    10. The SCR is connected back to back with diode and output is 48VDC
    11. There should be deviation of high and low output alarm
  • #3314

    nestbulala
    Participant

    This is the schematic for the Automatic Battery Charger using PIC16F690

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