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TMS320F280041-Q1: How is Rs defined for ESMO routines as described in TIDUBE5 Dual Motor Control Interleaved PFC for HVAC Reference Design

Bruce Nielsen
Prodigy 170 points
Part Number: TMS320F280041-Q1
Other Parts Discussed in Thread: C2000WARE

Hello,

I'm following the code for the ESMO and its not clear how Rs is defined as used in the ESMO routine.  Is it phase resistance, phase to phase resistance, or the value you get when you measure resistance from Phase A to PhaseB/PhaseC tied together?

In ESMO_setParams it uses pUserParams->motor_Rs_Ohm but its unclear how to measure this value.  In that same routine there baseVI is calculated and there is a 2.0f term in the calculation.  I believe it has to do with Rs and scaling it but its not clear.

I am using the Universal Motor Project for my reference work on this which I got from the C2000Ware_MotorControl_SDK_4_00_00_00.

Can you help clarify this.

Thanks - Bruce

  • 0
    TI__Guru** 109810 points

    It's phase resistance that equals to the half of the line to line resistance. You may try to get these motor parameters (Rs, Ls and BEMF constant) from its manufacture.

    Yes, the baseVI is used for the parameters scaling, it equals to  scale voltage / (scale current / 2).

  • +1
    Prodigy 170 points

    Hello,

    Thanks.  So the current is normalized so +/-1 equals +/-Full Scale Phase Current which is 1/2 of the full measurable range prior to the offset being removed.  This makes sense.  I had confused myself with voltage_sf as there are two values used (one from pUserParams and one from esmo constants) and they are different values.