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Need help on 3 phase sine generator(phase shifter)

PostPosted: Thu Nov 29, 2012 11:21 pm
by Fiz
Greeting,

i'm doing simple 3 phase sine generator by using phase shifter method, but i having on problem on these situation :
1)cannot generate sine wave output(hardware) on oscilloscope(i got straight line output voltage,and miss 1 phase voltage output) as produced by the simulation software i used (Multisim 10.1), please take a look on the below picture.

2)any idea the indicator for this project,i run out of idea..because the output voltage for this project is very low(the max i could get about 3v-4v), please take a look on the circuit at the below picture

Please do not hesitate to comment and give your suggestion on this project, because i'll really appreciate it and i need to improve the project.

Re: Need help on 3 phase sine generator(phase shifter)

PostPosted: Fri Nov 30, 2012 12:04 am
by Brian Griffin
Fiz WROTE:Greeting,

i'm doing simple 3 phase sine generator by using phase shifter method, but i having on problem on these situation :
1)cannot generate sine wave output(hardware) on oscilloscope(i got straight line output voltage,and miss 1 phase voltage output) as produced by the simulation software i used (Multisim 10.1), please take a look on the below picture.

2)any idea the indicator for this project,i run out of idea..because the output voltage for this project is very low(the max i could get about 3v-4v), please take a look on the circuit at the below picture

Please do not hesitate to comment and give your suggestion on this project, because i'll really appreciate it and i need to improve the project.


I'll build the same circuit according to this and test it if I'm free this weekend - I have an oscilloscope at my side. I have to get the 1uF caps and the 22k resistors first, they got ran out. :)

Re: Need help on 3 phase sine generator(phase shifter)

PostPosted: Fri Nov 30, 2012 12:38 am
by Fiz
Dear Brian, thanks for reply and the help you offered,i really do appreciate it.
I've something to ask,do the circuit is too simple and should i consider to use other circuits such as the picture below.
(1st circuit i took from here http://www.edn.com/design/analog/431832 ... d-outputs#)
(2nd circuit i took from allaboutcircuit from, and the author said the output of the circuit couldnt be more than 10k impedance else the circuit wont work if the impedance exceed 10k)
i wish to put indicator(hardware) on the output so the project could be much more attractive rather than showing on oscilloscope only..
Please do not hesitate to comment more..and thanks in the advance.

Re: Need help on 3 phase sine generator(phase shifter)

PostPosted: Fri Nov 30, 2012 9:22 am
by Brian Griffin
Fiz WROTE:Dear Brian, thanks for reply and the help you offered,i really do appreciate it.
I've something to ask,do the circuit is too simple and should i consider to use other circuits such as the picture below.
(1st circuit i took from here http://www.edn.com/design/analog/431832 ... d-outputs#)
(2nd circuit i took from allaboutcircuit from, and the author said the output of the circuit couldnt be more than 10k impedance else the circuit wont work if the impedance exceed 10k)
i wish to put indicator(hardware) on the output so the project could be much more attractive rather than showing on oscilloscope only..
Please do not hesitate to comment more..and thanks in the advance.


Hello,

Unfortunately I did not study much on analog or power electronics - only one basic semester back then since I did not major in E&E. I'll offer advice as much as I can.

If the 1st circuit works well and too simple, you should have chosen the 1st circuit. It's easier to fix problems compared to the 2nd one.

Also, any other alternatives than using analog circuits? Did your school project requires you to specifically use analog? If not, you may consider using a microcontroller. Some PIC24 microcontrollers contain hardware that allows you to generate multi-phase waveforms.

Re: Need help on 3 phase sine generator(phase shifter)

PostPosted: Fri Nov 30, 2012 12:35 pm
by Fiz
Thank you Brian for your response, its actually my Technology Electric mini project. My lecturer ask to make a 3 phase generator project, and i proposed some sort of circuit with an input directly tapped from 240 VAC supply voltage and the circuit are using expensive component such as power mosfet, so he suggested me to make simple 3 phase generator with using phase shifter method.

My subject is actually not quite much related to phase shifter(maybe in power electronic), i just wish to have a project can use hardware indicator output. What do think about this circuit as the below picture.

Really appreciate your reply,thanks.

Re: Need help on 3 phase sine generator(phase shifter)

PostPosted: Fri Nov 30, 2012 4:07 pm
by Brian Griffin
Start from making a simple sine-oscillator first. One sine wave. There are analog circuits on these online, and you have to search it.

If you can use digital systems - I would recommend a microcontroller. You may need to use a "table lookup" for these kind of things, or other methods on sine wave generation. Here is one example, but using an induction motor.

Note: Be very careful when you deal with high voltage alternating currents. They are deadly. Observe safety rules in the lab, and wear grounding shoes if possible.

Re: Need help on 3 phase sine generator(phase shifter)

PostPosted: Sat Dec 01, 2012 12:31 am
by Fiz
Thanks for your reply Brian,i appreciated your suggestion and i just started my 2nd hardware circuit,i missed a few components,i'll find it at electronic shop so by tomorrow i could complete the circuit. Btw, the circuit is the one i took from allaboutcircuit(the new circuit that i took from allaboutcircuit, the one using LM324).

The reason i choose the circuit because its has simple configuration and common component. So after all, i guess i dont have to make the indicator since the scope i covered only simulation and hardware for oscilloscope.In the case,i'll further the studies on 3 phase generator in next project. Right now,i only have to do research and development for 3 phase generator.

Again,thank you Brian, if you have any suggestion,please do not hesitate to left comment here.

Re: Need help on 3 phase sine generator(phase shifter)

PostPosted: Sat Dec 01, 2012 9:46 am
by Brian Griffin
Fiz WROTE:Thanks for your reply Brian,i appreciated your suggestion and i just started my 2nd hardware circuit,i missed a few components,i'll find it at electronic shop so by tomorrow i could complete the circuit. Btw, the circuit is the one i took from allaboutcircuit(the new circuit that i took from allaboutcircuit, the one using LM324).

The reason i choose the circuit because its has simple configuration and common component. So after all, i guess i dont have to make the indicator since the scope i covered only simulation and hardware for oscilloscope.In the case,i'll further the studies on 3 phase generator in next project. Right now,i only have to do research and development for 3 phase generator.

Again,thank you Brian, if you have any suggestion,please do not hesitate to left comment here.


What's the indicator for the project? Is it some kind of LED that shows it works, or an LCD panel which shows its status?

Do you have an actual oscilloscope to test on the 1st circuit? Make sure you get one sine wave. I believe that the sine wave produced in the simulation/hardware on the 1st circuit isn't really rounded as it has sharp edges. Sharp edges or staircase effect on sine wave leads to distortion, and eventually power loss.

Re: Need help on 3 phase sine generator(phase shifter)

PostPosted: Sat Dec 01, 2012 10:19 am
by Fiz
Thanks for your comment, i doesnt have oscilloscope, i used the one at laboratory, i do not know what it the circuit problem, so i will try 1 more time for 1st circuit i that i have troubleshoot and the 2nd one that i just assembled.

If the circuit work, i just continue making some sort of calculation and theory about the phase shifter and 3 phase generator.
Thanks again for your comment.

Re: Need help on 3 phase sine generator(phase shifter)

PostPosted: Sun Dec 02, 2012 1:00 am
by Fiz
Helo again,i've something to ask, is that possible to use indicator in simulation software from my 3 phase generator output, for an example, animation motor, so i can prove the circuit succeed produce 3 phase sine like real hardware, but just simulation.
Thanks in advance.