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CCS/TMS320F28054F: Instaspin FOC Lab 1B issues

Braden Loughnane
Intellectual 370 points

Part Number: TMS320F28054F

Tool/software: Code Composer Studio

I'm trying to run lab 1b on a custom board and driver. Current and voltage readings from the ADC seem reasonable and EPWM 1, 2, and 3 are all configured correctly. The motor is vibrating, but not rotating. It is hitting the current limit immediately (set at 3 A).

Something that I've noticed that absolutely cannot be correct is that all three phases of the motor are in sync (1/2/3 top in sync, 1/2/3 bottom complimentary).  (A_TOP and B_TOP, V vs. time)

Of course the motor will not spin when this is the case, but I can't figure out why this would be happening.

  • 0
    Intellectual 370 points

    I now understand that the duty cycles are changing, so this isn't a problem. However, the motor still does not spin. My configs are freq_low = 72.5, freq_high = 725.1, freq_max = 870.1, volt_min = 4.4, volt_max = 29.6. Motor is u10 kv100 t-motor

  • 0 in reply to Braden Loughnane
    TI__Guru** 116850 points

    Keep tuning the following until the motor spin smoothly if you don't know the spec. of the motor. Make sure that the PWM output and gate driver work well before doing that.

    #define USER_MOTOR_FREQ_LOW (10.0) // Hz - suggested to set to 10% of rated motor frequency
    #define USER_MOTOR_FREQ_HIGH (100.0) // Hz - suggested to set to 100% of rated motor frequency
    #define USER_MOTOR_FREQ_MAX (120.0) // Hz - suggested to set to 120% of rated motor frequency
    #define USER_MOTOR_VOLT_MIN (3.0) // Volt - suggested to set to 15% of rated motor voltage
    #define USER_MOTOR_VOLT_MAX (18.0) // Volt - suggested to set to 100% of rated motor voltage

  • 0 in reply to Yanming Luo
    Intellectual 370 points

    Thanks.

    I'm hesitant to make those changes before I address this issue: the board is heating up quickly when PWM is enabled for this lab.

    Could this be a problem with the deadband? I see that it is configured in hal.c, but something isn't working.

    It seems like the phases are shorting. Here's some graphs of what I'm seeing for phase current and current from the power supply, both seem erratic and the power supply current is spiking way too high.