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TIDA-00195: what if we use IGBT with Anti-parallel diode for breaking ?

Dave Hunson
Expert 1730 points
Part Number: TIDA-00195

Hi everyone!

I am using 80 ohm resistor for breaking 

I would be happy if you answer my questions: 

1.would it be possible to use IGBT with Anti-parallel diode for breaking instead of  Q1 which is APT70GR120L(Without Anti-parallel diode)?

2.what  D2 is doing  in Breaking circuit? would it be possible to omit it ?

in most of power modules the Breaking IGBT does not have Anti-Parallel Diode and instead the diode is in collector of IGBT  ! why is that ?

thanks for your attention

Regards.

Dave.

  • 0
    TI__Prodigy 640 points

    Hi Dave,

    Thanks for the questions.

    1. Yes, it is possible to use a IGBT with anti parallel diode - this will not affect the braking operation.

    2. D2 is used as freewheeling diode when IGBT is turned off and there is energy in the leakage inductance(of the resistor path) that needs to be freewheeled. In the absence of D2, the voltage at collector of IGBT may increase above rated value of IGBT due to leakage inductance during IGBT turn-off.

    Hope this helps!

    Regards

    Siva

  • 0 in reply to Siva Mohan
    Expert 1730 points

    Thanks dear Siva ,
    It helped a lot...

    Best wishes.

    Dave. 

  • 0 in reply to Dave Hunson
    Expert 1730 points

    Dear Siva

    The other things which confused me is, in this  design (TIDA-00195) used lunch-pad (TMS320C28027F) ,as far as I know, in C2000 sires we need 3 current feedback and 4 voltage feedback(Va,Vb, Vc ,Vdc ).

    so my question is ,would it be possible to run the motor without Voltage feedback signals?

    Regards.

    Dave.

  • 0 in reply to Dave Hunson
    TI__Prodigy 640 points

    Hi Dave,

    It is possible to run the motor in open-loop using V/F or scalar control without any feedback signals - however, it is advisable to have at least 2 phase currents and DC link voltage feedback for protection. Closed loop control requires 2 phase current signals and DC link voltage(if DC link can vary across normal operating conditions).

    For isolated current sensing please refer to TIDA-01455 and for non-isolated current sensing to TIDA-01456.

    Hope this helps!

    Regards

    Siva