# Analog And Digital For Soft Starter Control Circuit

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Below is the simulation of single phase soft start for induction motor. Am I able to find a microcontroller to replace the control circuit and function as same as it?

http://i71.photobucket.com/albums/i156/doinfinity/singlephase.jpg

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Hello doinfinity

The answer is yes, you can certainly use a microcontroller to get the same result.

Remeber, that the microcontroller will do it all digitally.

Looking at the diagram, can you explain why, on the bottom rung, there is a constant added in?

Best regards,

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• 2 months later...
Hello doinfinity

The answer is yes, you can certainly use a microcontroller to get the same result.

Remeber, that the microcontroller will do it all digitally.

Looking at the diagram, can you explain why, on the bottom rung, there is a constant added in?

Best regards,

hi, the constant '5' is added so that to move the waveform above the zero line.

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Hello doinfinity

hi, the constant '5' is added so that to move the waveform above the zero line.
Why would you do that? surely this will make the output asymmetrical which will introduce even harmonic currents and is definitely not what you want?

Best regards,

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Hello doinfinity

Why would you do that? surely this will make the output asymmetrical which will introduce even harmonic currents and is definitely not what you want?

Best regards,

Hi marke,

I have made some modification on the control circuit. Below is the circuit, the graph of ramp, the waveform before plus constant 5 and waveform after plus constant 5.

http://i71.photobucket.com/albums/i156/doinfinity/ramp.jpg

http://i71.photobucket.com/albums/i156/doinfinity/before_5.jpg

http://i71.photobucket.com/albums/i156/doinfinity/after_5.jpg

As I am going to use 1 ramp block to compare the triangular generated from the positive and negative cycle, so i add the constant 5 to the negative triangular waveform to make it comparable to the ramp.

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