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TMS320F28035: Field Oriented Control for ACIM

pujit gandhi
Prodigy 30 points
Part Number: TMS320F28035

I was working on developing software for controlling torque and speed of 3 Phase AC Induction Motors using Field Oriented Control aka Vector Control.

My motor has following details as per the nameplate:

Rated Power : 3 kW Rated Voltage : 48VAC Rated Current : 54Arms Rated Speed : 2660 RPM Poles : 4 Make : Nidec Max. Speed = 6000 rpm.

I have tested my software for no load speed control upto 3000 rpm . I have kept magnetizing command current to be around 20A.

My motor consumes 2.5A DC and 14Arms ac current at 3000 rpm.

I am doing calculations in pu system where 1pu = 32767.

I observed that initially , output variables VD and VQ both are positive , but as speed ramps up , VQ keeps increasing upto 0.75pu but VD reduces and even goes in negative. (from 0.125pu to - 0.125PU.

Kindly help me in concluding my observations.

  • 0
    TI__Guru** 115480 points

    Since you are using your own estimator, it's difficult to provide more supports for you, just give a little bit common comments as below.

    1. Run the motor with open loop like v/f control to check if the current and voltage signals are good on your board.

    2. Run the motor with current closed loop to verify the current sensing and regulator.

    3. Try to install a position sensor on the motor to verify if the estimator you used can estimate the right rotor angle and speed.

  • 0 in reply to Yanming Luo
    Prodigy 30 points

    Hi thanks for reverting.

    I am using encoder for position sensing.

    1. I haven't  checked voltage and current signals because the prototype design is very compact with no test points.

    2. I have run motor at 450 rpm in current closed loop with iqref limited  to 46Arms , when i stopped with my bare hands  , current got limited at 46 Arms.

    At beginning , when speed ref is 0 , and only d axis current command is given , vqref is 0 and vdref is 4500 , then when speed ramps up , vqref starts increasing till it reaches 32767 (1pu), but after 2000 rpm , vdref slowly slowly decreases and goes into negative. Is this observation ok or something  isn't  working right?

  • 0 in reply to pujit gandhi
    TI__Guru** 115480 points

    As mentioned above, it's very difficult to give you more comments since you are using your own software and hardware, and there is no enough information for understanding your questions. Please try to use the step 1 and 2 to check the current and voltage sensing circuit on your board first, to make sure that the offset of the current sensing is calibrated and the scale value is set correctly according to your own board.