Author Topic: Thyristor rectifier controller IC?  (Read 2524 times)

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Offline Faringdon

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Thyristor rectifier controller IC?
« on: November 25, 2021, 05:28:58 pm »
Recently I saw a full wave thyristor bridge power supply (it may have been a 3 phase rectifier I forget). The  thyristors were getting controlled by what on the schem appeared to be a “DTM452” Thyristor controller.
However, I cant find “DTM452” anywhere on the web.
Do you know of a similarly names thyristor controller, as I may have got the name slightly wrong? Indeed, if not, then do you know of any Thyristor controller IC’s?

Offline mag_therm

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Re: Thyristor rectifier controller IC?
« Reply #1 on: December 02, 2021, 01:34:31 am »
From 1960's on, thyristors ( scr) were usually for high power conversion, not for consumer markets.
With gate drives of ~ 1 Amp peak, fast risetime and long duration, and control feedbacks of 400V ~ to  kV levels ,
and a multitude of topologies, there was probably little ability or commercial incentive for development of generic ICs.

( That is in comparison to say, SG3525 etc that could directly drive FET or IGBT in pwm  for lower powers and voltages)

In my experience, particularly in UK and EU, the manufacturers would encapsulate their own control circuits and give an OEM part number.
If the equipment you saw is old, perhaps that is the part number.
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Offline Clem_Jest

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Re: Thyristor rectifier controller IC?
« Reply #2 on: December 13, 2021, 05:34:29 pm »
A while ago i "developed" a board based on the TCA 785 for a single phase transformer of around 10 kVA ( roughly 8 - 9 kW) and it was meant to be a rectifier transformer for electrochemical applications.

It worked out pretty good, basically the transformer output rating on the secondary was 10VCA @1000 amps so the goal was to use a pair of back-to-back SCR´s in phase angle control scheme (installed in the primary side of course) in order to achieve variable output at the low voltage side. (everything thanks to the TCA 785 IC, no microcontroller)

I thought it wouldn´t work since imo it was far from perfect but it turned out to work pretty good. still working to this day

Hope this helps
« Last Edit: December 13, 2021, 05:39:45 pm by Clem_Jest »
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Offline trobbins

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Re: Thyristor rectifier controller IC?
« Reply #3 on: December 14, 2021, 01:01:02 am »
To support what mag-therm summarised, if the equipment was commercial/industrial and used control thyristors on primary or secondary side then the thyristors were likely controlled by the OEM's control board.  Such control boards often have a variety of analog input capabilities for different sensed inputs, and likely a PLL to manage sync to a limited range of mains freq, and then logic gating to drive specific thyristors and then isolation pulse transformers to drive particular thyristors - so not normally a single controller IC format, and typically made as bullet proof as possible due to industrial conditions.  I'd look for any manufacturer identification of the power supply equipment, or any service labels/records, and go from there.
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