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Topic: AC Phase control - H11AA1 is 16ms not 8ms (Read 4642 times) previous topic - next topic


Dec 22, 2016, 08:30 pm Last Edit: Dec 22, 2016, 08:36 pm by zhomeslice
I'm Working on a project that is similar but I took a different direction to control the AC Phase using all hardware PWM control with only a minimal interrupt capture to reset the PWM timer.

Take a look at this thread:

SOLVED] PWM Fails when adjusting Timer1 Pin 9 (Fast PWM, 10 Bit mode 7)

Working code is in my post for you to try :)



If you look at your latest oscilloscope trace, you will see that at the zero crossing, the trace starts ramping up towards 5V, but never gets there before it begins to ramp down again.  I think that you need to reduce the current through the LEDs in the optoisolator, by increasing the value of the series resistors (R1 & R2 on the page you linked to) so that there is a longer period when the LEDs are actually off.

The waveform shown on the page you linked to goes right up to 5V, and has a flat top.  I'm not sure whether that is real, or idealised, however I think you should try and achieve that sort of waveform, with the flat top being as narrow as possible.


Dec 23, 2016, 03:10 pm Last Edit: Dec 23, 2016, 03:11 pm by JohnLincoln
Yelkenli, I see from the time-zone in your profile that you are probably in Europe.

The waveform shown on the page you linked to shows the supply voltage going up to 120V, implying that the circuit has it's component values selected for US territory.
(it's actually wrong, since it is the RMS voltage that is 120V, the peak is higher)

I suggest that you double the values of R1 and R2 to take into account the higher supply voltage, if you are indeed in Europe.

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