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TMS320F28027F: identifying Issue

Dave Hunson
Expert 1740 points
Part Number: TMS320F28027F


Hi every one 

I wanted to identify my motor but I encounter with problem

my information

motor :ACIM

max RPM = 1500

motor voltage 380v

max current 7 A

 

so what I defined in user.h was:

TYPE= MOTOR_Type_Induction;

NUM_POLE_PAIRS= (2);

RATED_FLUX =(6.25);   ((0.81*380v)/50Hz)

RES_EST_CURRENT =(3.0);

MAX_CURRENT =(7.0);
FLUX_EST_FREQ_Hz =(5.0);

 other  parameter is NULL

after Identification the  

1.MAGNETIZING_CURRENT became 5.5! which is too high 

why is that happened ?

2. how to know when Ls_d = Ls_q ?

BTW,when I put  Ls_d = Ls_q it will perform much smoother and better .

any idea .I would be happy to know .

Regards

Dave. 

  • 0
    TI__Guru** 115500 points
    1. What h/w board are you working on? TI EVM Kit? Or your own? Please make sure the current and voltage sampling signals are good enough for motor control if you used your own board.
    2. Please ensure the voltage and frequency are the rated value from the motor 's nameplate or its manufacturer, not the maximum values.
    3. Only an Ls (Stator leakage Inductance) is used for ACIM in instaSPIN-FOC that should be set to both Ld and Lq with the same value.
    4. Ensure the rotor is locked to identify the Ld and Rr after completed Flux identification, and the motor runs without any load for the whole identification process.
  • 0 in reply to Yanming Luo
    Expert 1740 points

    Hi Dear Luo,

    1. What h/w board are you working on? TI EVM Kit? Or your own? Please make sure the current and voltage sampling signals are good enough for motor control if you used your own board.: it is my own board but I can be sure about it ,since I get my motor(3kw) to be identified at the lower range of voltage 220v . and also my board could identify 11kw motor with 380V.

    -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
    2. Please ensure the voltage and frequency are the rated value from the motor 's nameplate or its manufacturer, not the maximum values.
    :ya ,every thing were set base on motor 's nameplate

    -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

    3. Only an Ls (Stator leakage Inductance) is used for ACIM in instaSPIN-FOC that should be set to both Ld and Lq with the same value.
    :you made a good point here ,So in some case those two are not the same. so which one should be stored to set for both Ld and Lq?

    -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

    4. Ensure the rotor is locked to identify the Ld and Rr after completed Flux identification, and the motor runs without any load for the whole identification process.
    :ya. I follow all of those rule ,i know these are should be done.

    I would be happy if you answer item 3.

    thanks in advance.

    regards.

    Dave.

  • 0 in reply to Dave Hunson
    Expert 1740 points
    Dear Luo

    2.would you please tell me the formula for changing USER_VOLTAGE_FILTER_POLE_Hz?
    is that the USER_VOLTAGE_FILTER_POLE_Hz formula or not?
    USER_VOLTAGE_FILTER_POLE_Hz =1/(2*3.14)*(R_parallel)*47nf
    what is R_parallel?
  • 0 in reply to Dave Hunson
    TI__Guru** 115500 points
    1. Good.
    2. Ensure the USER_MOTOR_RATED_FLUX is set correctly. You might try to use (0.71* Rated V (line-line) / Rated Freq (Hz)) to calculate this value.
    3. Often, there are stator leakage inductance, stator referenced rotor leakage inductance, magnetizing inductance in the datasheet of an ACIM provided by its manufacturer. You might have a look at Section 4.8.1 of instaSPIN user's guide (SPRUHJ1G). The identified Ld and Lq should be the same value for ACIM by InstaSPIN-FOC that is Ls also.

    For USER_VOLTAGE_FILTER_POLE_Hz calculation, you might have a look at section 5.2.4 of instaSPIN user's guide (SPRUHJ1G).
  • 0 in reply to Yanming Luo
    Expert 1740 points

    Hi dear Luo

    sorry for delay.

    2. "Ensure the USER_MOTOR_RATED_FLUX is set correctly. You might try to use (0.71* Rated V (line-line) / Rated Freq (Hz)) to calculate this value": it is obvious that (0.8165*220.0/60.0) =2.99
    some thing that makes me  confuse is that you mentioned" (0.71* Rated V (line-line) " why?!

    so for 3 phase input (0.8165*380.0/60.0)=5.17 is that correct?

    thanks for helping :).

    Best wishes.

    Dave.

  • 0 in reply to Dave Hunson
    TI__Guru** 115500 points

    Right. The voltage is line to line, and you could use a little smaller coefficient to calculate the rated flux as I mentioned, not the ideal value, 0.8165. The smaller value is Just for identification to consider the voltage drop on resistance, is not very critical. But the scaling value of current and voltage, and the voltage filter pole are very important, must be calculated according to the h/w board. The USER_MOTOR_RES_EST_CURRENT and USER_MOTOR_FLUX_EST_FREQ_Hz should be set correctly based on motor specs.
    Please post some current waveform to help to analysis the problem if you have any further questions. Thanks.