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Original question:

TMS320F28069F: Rotor position calibration during PMSM startup

TMS320F28069F: The motor cannot reach the maximum speed

hongwei Quan
Prodigy 190 points
Part Number: TMS320F28069F

Dear experts: I am conducting a PMSM sensorless experiment, Lab10e, but I encountered a problem that the motor cannot reach the maximum speed.

Motor parameters:

Line voltage: 220V, rated speed: 2500rpm, 4 pairs of poles, 3 phases, rated current: 7.5A, line to line resistance: 1.01 Ω, line to line inductance: 2.94mH

user.h:

USER_ MOTOR_ Rr (NULL)

USER_ MOTOR_ Rs (0.505)

USER_ MOTOR_ Ls_ d (0.0147)

USER_ MOTOR_ Ls_ q (0.0147)

USER_ MOTOR_ RATED_ FLUX (0.8165*220.0/(2500*4/60))

USER_ MOTOR_ MAGNETIZING_ CURRENT (NULL)

USER_ MOTOR_ RES_ EST_ CURRENT (0.2*1.414*7.5)

USER_ MOTOR_ IND_ EST_ CURRENT (-0.2*1.414*7.5)

USER_ MOTOR_ MAX_ CURRENT (1.5*1.414*7.5)

USER_ MOTOR_ FLUX_ EST_ FREQ_ Hz (20.0)

Runtime: When the speed increases, Flux_ VpHz decreases. When it exceeds about 950rom, it does not change. At the same time, Vs also increases, and motor noise also increases. When the speed reaches about 1450rpm, Vs suddenly changes to 0.5 and Vd suddenly changes to - 0.5, that is, the maximum modulation ratio. The motor runs unstably, and the speed decreases to about 1350rpm.

What is the reason? ADC sampling is correct because I have implemented the FOC for ACIM experiment.Is the V/Hz too high? Maybe USER_ VOLTAGE_ FILTER_ POLE_ Hz incorrect?No answer found in the forum.

Regards!

Quan

  • 0
    TI__Guru 50511 points

    Quan,

    The subject matter expert is out of office this week. He will be back in office next Monday. Please expect response by Monday/Tuesday. Sincere apologies for delay in response.

    Regards, Santosh

  • 0 in reply to Santosh Jha
    Prodigy 190 points

    OK, Santosh thanks

    Regards!

    Quan

  • 0 in reply to hongwei Quan
    Prodigy 190 points

    Add: use Lab2a to re identify the motor, RATED_ FLUX=0.93,Rs=0.565,Ls_ D/q=0.00145, which is not much different from the previous calculation data. Lab3a runs, and the maximum speed of the motor reaches about 1950rpm. Flux_ VpHz changes from about 1.0 to 0.7, which should indicate that the DC voltage is not enough, because the setting is vs=0.5, and the DC voltage is about 315 V. Set RATED_ FLUX=0.8, the motor can reach 2500rpm. I don't know gMotorVars.Flux_VpHz How to calculate , how to run it in control, and what rules to set RATE_ FLUX in future applications？

  • 0 in reply to hongwei Quan
    TI__Guru** 114200 points

    What type is the motor you used? You shouldn't change Flux and should use the identified value, and also use the identified Rs, Ls as well.

    What's the rated speed and voltage of the motor?

  • 0 in reply to Yanming Luo
    Prodigy 190 points

    Dear Luo:The motor type is IPMSM; Yes, I used the identification parameter Rs/Ls/Flux_ VpHz, but the speed still cannot reach the rated speed of 2500rpm; Motor nameplate parameters: rated voltage AC 220V, rated speed 2500rpm.

    Regards!

    Quan

  • 0 in reply to hongwei Quan
    TI__Guru** 114200 points

    Try to increase the DC bus voltage to see if the maximum running speed is increasing accordingly.

  • 0 in reply to Yanming Luo
    Prodigy 190 points

    Dear luo:Yes.thsnks reply!

    Regards!

    Quan