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Pulse Transformer for Rectifier Circuit

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ZaarZ

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Hello all,

Im doing my final project entitled Single Phase Controlled Rectifier hardware design. So, before i build the hardware, i simulate the circuit using MULTISIM first, but... the problem arise when it comes to the pulse transformer (PT), which is none of PT is appeared in the Multisim. Does anyone know how to model PT using MultiSim ?

And,

What is different between Pulse Transformer (1:1:1), PT 1:1+1, and PT (1:1). Which are most suitable and economical for my circuit as attached below ?

**broken link removed**

and which of these PT is recommended for the circuit ? Sorry, i know nothing about PT. Anyway, thanks in advance..

**broken link removed**
 
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A pulse transformer is just a transformer optimized to transmit pulses with minimum distortion.

A (1:1:1) is a transformer with three identical windings. A (1:1) is a transformer with two identical windings. Don't know what a 1:1+1 transformer is.
 
Okay.. Thanks for d info... Maybe i'll select a (1:1:1) PT to trigger the gate & cathode of SCR...
 
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Okay.. Thanks for d info... Maybe i'll select a (1:1:1) PT to trigger the gate & cathode of SCR...
If you are just driving one SCR you only need a (1:1) PT. One winding output goes to the SCR gate and the other output goes to the cathode (see the Driver Circuit schematic in your post).
 
its a trnasformer to give isolation to the SCR too. commonly ferite core transformers are used. a good example is the driver for horizontal transistors in TV sets.
 
If you are just driving one SCR you only need a (1:1) PT. One winding output goes to the SCR gate and the other output goes to the cathode (see the Driver Circuit schematic in your post).

Nope, in my case.. i design fully controlled rectifier circuit using four SCR(2N5061). so, there's a need to use two PT with ratio of (1:1:1) to a pairs of SCR during positive cycle, and another pair of SCR duing its negative cycle. If PT (1:1) is used, maybe i need four PT to trigger all of the SCR. Anyway, please correct me if im wrong..
 
Because TRIAC's avoid the need for using multiple SCR's - it's also far more normal these days to use opto-couplers than transformers.


Yap, the triac is designed as two thyristor in anti-parallel with each other. But, i would like to use four SCR (fully controlled bridge rectifier) instead of using triac. Futhermore, the application of the triac is not much been taught in my syllabus. So, my knowledge about the triac is zero for now. T_T
 
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What does a "fully controlled rectifier" do?

In case of my project, i need to design fully controlled rectifier (Bridge type) with four SCRs. The output at the load (impendance, consists of resistor and inductors) can be controlled by varying the delay angle of firing circuit. Thats all.. its sound easy, but to design the firing circuit quite complicated and troublesome though.. Btw, the objective is mainly to understand what,which,how,and learn characteristic of output waveform fully controlled bridge rectifier in term of DCM and CCM conditions. :)
 
Nigel, yap. just a project, final year project to obtain deg of elec. engine. T_T

Rectifier supposedly converting AC to DC, right ? Dunno is there any method to use rectifier to get AC output. oh, i really lack of knowledge here. T_T Please guide me~
 
For AC you would use either a single TRIAC, or (in the VERY distant past) two SCR's back to back.

For DC you would use either a bridge rectifer followed by a single SCR, or a bridge rectifier where TWO of the diodes are replaced by SCR's.

I can't think where using four SCR's in a bridge might come in useful?.

No disrespect, but it seems a bit lacking for a final year project?, basically just copying an ancient design. I thought final projects had to show initative, originality and usefulness?.
 
Its okay for me, this is learning process.. I dont mind about the disrespect thing in order to get knowledge from your expertise.

Btw, from what ive learned from the books-thing.. using 2SCR and 2Diode in a bridge type only produced half-controlled rectifier, isnt it?

As you said earlier, the circuit above is direct-copied from the books, but for me.. i need to design a hardware for that circuit. It means that i need to re-model the circuit (changing different type of components used, because some of the components is discontinued in manufactured and too hard to find these days) and to simulate using multiple type of software today (in my case, i just use multisim and pspice) before making the real circuit hardware (testing it using protoboard and mounting on PCB)...
 
No, it controls all half cycles, one SCR controls each alternate half cycle.

Okay, i may accept ur opinions.. im just referring in the Thyristor Engineering book, written by MS Berde (page74) which stated that "A rectifier with 2 diodes and 2 SCR is called half controlled bridge". Maybe i got a bit misunderstand over there, which the book author may said that 1 SCR operate during +ve cycle and another 1 during -ve cycle to form fullwave rectifier. Thanks for correct me..

Anyway, just in case i use 2 SCR and 2 diode, does the circuit still work? By using only one Pulse Transformer PT6E with ratio (1:1+1) manufactured by OEP (got 200u Vs ET rating) [as attached in the Farnell list], does it can trigger each of the SCR's ?
 
since you are working on single phase its not so critical to get switched, but in 3 phase your switching should not overlap thus making short circuit.
for high power design package discipation is a big concern so SCRs are still in use. Triacs are used in other application where static switching is required for AC.
 
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