[PIC] SCR Dual Converter - Is this Circuit Correct ?

Dual SCR Converter - Is this Circuit Correct ?

Hi experts,

I opened this new thread because this project is different from my earlier project which was SCR Bridge Control. This project is SCR Dual Converter. I have attached the Proteus Simulation, Proteus Simulation Video and Schematic. Please check the Schematic and tell me if the Circuit is Correct. In real hardware V3 source will not be connected to ground and the SCR Bridges will not be connected to chassis or ground.

In Proteus it is working fine. I need a confirmation regarding the circuit to build the real hardware. I also need to design the PCB Layout in Proteus.

There was a connection problem in simulation. The AC voltage source used for SCR Bridges have one of its connection grounded and this is making the Bridges to work as half wave rectifiers. I am trying to fix the simulation circuit. Will post the new circuit soon.

- - - Updated - - -

Here is the fixed simulation. Now it is working as Dual Converter with bridge output. I will post the Proteus Simulation video soon for those who don't have Proteus.


There is a simulation bug or corrupted simulation file (because code is correct) and so you have to press the buttons only after the simulation time has elapsed 1.5 seconds. If buttons are pressed before simulation time is 1.5 seconds then it is not working. I have checked the code and there are no delays. I don't know what is causing that delays. You can see that if buttons are pressed before 1.5 seconds simulation time then also the PULSE X pins are giving the output but bridge output will be zero. If anybody finds mistake in circuit please tell me.

To change motor direction you have to first stop the motor and then change the direction and then start the motor again. Leds indicate the status.

There were some wrong connections in the SCRs Anode to MOC3021 connections. I have fixed it. Here is the final project files. It contains Proteus Simulation and Schematic. Proteus file is in 8.6 SP2 format.

The chassis connection in the SCR circuit is not needed for realtime simulation and also in hardware but is needed to plot load current graph.

After the student submits the project I will post the code.

I built the circuit on hardware and tested the output of transformer (12V) using Oscilloscope and I see signal is clamped. why ?

Waveform is meaningless without related schematic and description. Where has it been probed, what's the load etc.

The output of the 12V transformer is measured using the probe. The 12V AC goes to two bridges (one for power supply and another for ZCD circuit) The 12V AC also goes to SCR Bridge input but SCRs are not ON. If I disconnect transformer output connections from bridge rectifier inputs and measure the signal then I get clean sinewave but if bridge rectifier is connected then 12V AC is clamped.

FvM said:

Waveform is meaningless without related schematic and description. Where has it been probed, what's the load etc.

Click to expand...

I can not see the picture in post #4 because it says that it contains errors. How did you see it ?

I see the image by simply clicking on the attachment. Don't know why it hasn't been posted with "Insert Image" function.

If it doesn't open in your web browser, try to download it and open it in a image viewer.