SCR Gate Driver arduino?

[stringerbell]

Line voltage compinsation, a CT feedback, current/voltage limiter, soft start. from what my research yielded is, most proper phase controll SCR driver's have zero cross DETECTION, a Pulse train transformer, and well that thing has a couple IC' s and looks like it has more going on then a MOC3032 like in

https://www.bristolwatch.com/ele/img/2scr.gif


that and i found audrino code for triac and zero cross but not for SCR control, and i remember you suggesting zero cross, isolated drives in a plastic box and a RCD (i ordered an RCD)

 

[stringerbell]

I just found this, do you think this is a viable solution, i already have an ardrino controlling a triac so this looks simple but will it work with a IRKT91/16? i see it says non sensitive SCR, and it shows just the gate pin, not the other two pins that are on the IRKT91

 

[KlausST]

Hi,

Line voltage compinsation, a CT feedback, current/voltage limiter, soft start. from what my research yielded is, most proper phase controll SCR driver's have zero cross DETECTION, a Pulse train transformer, and well that thing has a couple IC' s and looks like it has more going on then a MOC3032 like in https://www.bristolwatch.com/ele/img/2scr.gif that and i found audrino code for triac and zero cross but not for SCR control, and i remember you suggesting zero cross, isolated drives in a plastic box and a RCD (i ordered an RCD)

All this can be done with SCRs as well as triacs.

If you can use it for phase control depends on the driving circuit, not wether it is SCR or triac.
A triac has only one gate and therfore it needs a simpler driving circuit. But for the load/current control it will be the same.

There are MOCs with and without zero cross switching feature.

If you want phase control you need a zero cross detection for triac as well as for SCRs.

Klaus

 

[stringerbell]

do i need phase control? i want to dim a welder transformer like the basic analog non-ardino curcuit i first posted, i have a triac being fired with zero crossing with my audrino and a HAA11A, with an ardrino interrupt at zero, a pot adds a delay, then it fires the triac. So can i just not put the gates of the back to back SCR between the anode and cathode of the triac and just hope for the best (according to last image i posted its a way it can be done)? i just want to limit power for the transformer, the original circuit i posted is pretty rudimentary, im just trying to improve it a little if i can, the triac would probably work just fine for the welder current control, but i want to use these back to back SCRS, so what are u thinking could u maybe hint me toward a good easy to follow circuit, pretty soon im going to have to just cave in and spend 200USD on a SCR firing board, but i would hate to if i am so close

 

[KlausST]

Hi,

do i need phase control?

I don´t know. But you should know.

Full wave = low noise, low emissions. Zerocross switching. regulation in full 20ms (@50Hz) packets. (don´t use 10 ms half wave packets!). For 20% power regulation: 1 full wave ON, 4 Full waves OFF
Phase control: more noisy. Non zerocross swtiching = immediate switching. regulation by 0..10ms delay each halfwave. For 20% power regulation: 0..120° OFF, 120° ...180° ON.

Klaus

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Added:

So can i just not put the gates of the back to back SCR between the anode and cathode of the triac

Either triac or SCR. Don´t use both. It makes things complicated.

Klaus

 

[BradtheRad]

do i need phase control?

I used a triac with a plain potentiometer to control its turn-on, in a fan speed control which I constructed. I ignored the conventional triac circuit which has the capacitor, diac (neon bulb), etc. My design worked, although I ended up adding a couple more resistors to obtain better performance.

I believe this method only gives you turn-on during one slope of the AC waveform. Perhaps this is sufficient.

 

[stringerbell]

yeah, i just tried out the triac across 2 of the "high setting" welder primary wingdings (minimum is always on,, so theres only one manual switch now, and thats for medium Heat) its working brilliantly just tested it, now im just got to pay someone from peopleperhour to program the audrino to control my PWM wire feed controller, and current/voltage slopes + alicat mass flow controll valves for gas mixing + ethernet shied and a app or windows GUI made for it all, ill post diagrams of full setup when im done.