09-20-2013 10:49 AM
Hi,
I'm want to use PWM pulse to control ON-OFF 6 IGBT of DC-AC converter (3 phases). the hardware I had are NI cRIO-9074, NI-9263
, and NI-9225.
I dont know can I generater PWM pulses via what I had. if it can do, please give me some examble or document for it.
And I dont know if I just want to simulate the PWM pulse by labview without hardware. I have tried to do it by use 3 sines signal with different phase (0, -120, 120) ( modulation signal ) and 1 triangle pulse, then I compared each sine signal with triangle signal. ( the frequence of sine signal about 50Hz and the triangle pulses's 10000Hz). but I can get the right signal output like I hope (it not like the output of PWM signal)
thanks for your care
09-23-2013 01:33 PM
Hello aloalo,
What frequency of PWM signal are you trying to generate? Are you using FPGA mode or Scan Interface mode?
PWM generation is not the intended purpose of analog output modules, such as the NI 9263. That isn't to say that they aren't capable of doing PWM, but ideally, you would want to use a digital output card. I understand the 3-phase sine wave modulation signals, but could you tell me more about the purpose of the triangle wave?
09-23-2013 09:55 PM
hi WishKebab
thank you for your advise. Yes, PWM is an digital signal, I just have bought an output digital signal module, It is 9041 module. I'm very new in labview and FPGA so I can't get the output signal via the 9041 module. might you help me?
to generate PWM signal, we triangel signal to compare with each phrase of sine signal. if sine signal greater than triangel signal,PWM = 1, if sine signal is less than triangel signal, PWM signal = 0.
09-24-2013 05:30 PM
Hi aloalo,
Do you mean to say that you are now using an NI 9401 module? If that's the case, and you are using it in Scan Interface mode, you can easily set the PWM level by configuring the card itself for PWM mode.
~~SCAN INTERFACE MODE~~
KnowledgeBase: How Can I Perform Pulse-Width Modulation with an NI-9401 Using the Scan Interface?
http://digital.ni.com/public.nsf/allkb/0892C8D55C6D0C0E86257585004FD0B0
If you want to manually write the lines high or low, you can use the following example:
Example: Generate PWM Clock on cRIO Using Scan Mode
https://decibel.ni.com/content/docs/DOC-11079
~~FPGA INTERFACE MODE~~
Example: Pulse Train Generation with LabVIEW FPGA on CompactRIO
http://zone.ni.com/devzone/cda/epd/p/id/1726
10-16-2014 04:04 AM
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10-16-2014 07:10 AM
@cherryraj206 wrote:
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