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About 3 phase AC Induction motor

Anil Sahu
Prodigy 50 points
Other Parts Discussed in Thread: LM3S817

Hi,

We are using 3-phase AC induction motor for solar systems. For this we are using LM3S817 micro controller. we developed the code for 3-phase induction motor using redsuite3.0 IDE. When we are generating the sinewave 80% is the maximum dutyfunction we are getting at 50Hz. Is there any limitation for that or it is only the maximum. please provide the solution to get the 100% dutyfunction at 50Hz.  

  • 0
    TI__Expert 3445 points

    Anil,

    Are you using the PWM module on the LM3S817 to drive the gate driver or inverter bridge? Check section 7.3 of the LM3S817 errata to make sure that the errata is not occurring in your program.

  • 0
    Guru 117855 points

    Along w/John's errata guidance - is your report of, "80% max." that of your program's sinewave creation - or the PWM Generator's maximum developed duty cycle - or both?

    Our group has long (past) used similar 48 pin devices - and have never noticed so marked a limitation in duty cycle. 

    You are aware that both, "Dead Time" and "Minimum PWM Pulse Width" assignments - normally can be expected to, "reduce the maximum duty cycle" achieved.  Your report of a 20% reduction seems unusual...

    Beyond this - might some current (or other) feedback mechanism be active - and the source of, "duty cycle clipping?"

    Minus relevant PWM code - further diagnosis hindered...   (but I'd place some chips on 2 areas herein listed)

    to moderator: earlier placement w/in Stellaris Forum was correct...  LM3S817 was - and remains - Stellaris!