3 phase 6 pulse AC-DC 400V/400A circuit examples needed. Urgent!!! Help please!

[wizardgrt]

To all members who could help me with assignment,

Hello! I'm pretty unexperienced in SCR/thyristor/GTO thyristor circuit design... :sad: Although, two days ago I've got an assignment to design the 3 phase 6 pulse AC-DC 400V/400A circuit, with one of upper mentioned switching elements. The purpose of this circuit is to warm up the generator pole winding (without iron core), so it practicaly represents very low resistance element, about 16-17 mili Ohms (short circuit). I've already found a way to calculate the power electronic circuit, but main problem represents LACK OF SWITCHING ELEMENT GATE DRIVER CIRCUIT, and PHASE SYNCHRONISATION CIRCUIT. Any form of example will be a great help!!!


Sincerelly thankful!:roll:

 

[kak111]

THREE-PHASE CONTROLLED RECTIFIERS
Line Commutated Controlled Rectifiers (Thyristor Rectifiers), and Force Commutated PWM Rectifiers.
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OPERATION OF A 3-PHASE FULLY-CONTROLLED RECTIFIER
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STUDY OF 3- PHASE LINE COMMUTED THYRISTOR CONVERTER CIRCUIT
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Model 1681 Instruction Manual - Firing Circuits DC SCR Drives

 

[mtwieg]

I'm a bit confused. If you want to deliver power to a 16-17milliohm load, why would you try doing that with a 400V AC or DC supply...? Or is there some converter in between that you don't have to design..?

Anyways, for triggering the devices the simplest methods are pulse transformers and optotriacs. As for phase synchronization, I assume you're talking about zero cross detection? First you'll need a way to sense the three phases, then use comparators to sense zero crossings. Then the firing angle can be changed with some variable delays.