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Original question:

TMDSHVMTRINSPIN: Problem with the output waveform of the kit

TMDSHVMTRINSPIN: Problem with the output waveform of the kit

Green Deng
Expert 4490 points
Part Number: TMDSHVMTRINSPIN

Dear team:

My customers still have some questions about the output waveform of this kit:

ustomer tried to supply 60VDC to the motor, but the motor still couldn't rotate.

Moreover, it is observed with oscilloscope that hvkit has PWM output when providing low voltage, but there is no PWM output when providing high voltage.

Below is CCS expression window:

In addition, the customer found that: once the board is connected with high voltage, the PS21765 on the board will output a high level of 3.3V. According to the data manual, it is overcurrent protection. Why is this?

Best regards

  • 0
    TI__Intellectual 2890 points

    Green, per your description there seems to be over current fault triggered. One of the scenario which could trigger this condition is when V/F ratio is not set right.

    Can you look at user.h for the following parameters and make sure it got right values per the motor being used:

    #define USER_MOTOR_FREQ_LOW_HZ (20.0) // Hz
    #define USER_MOTOR_FREQ_HIGH_HZ (400.0) // Hz
    #define USER_MOTOR_VOLT_MIN_V (4.0) // Volt
    #define USER_MOTOR_VOLT_MAX_V (24.0) // Volt

    Further please confirm the control card being used and the examples are from MC-SDK.

  • 0 in reply to Navaneeth Narayanasamy
    TI__Expert 4490 points

    Hi Navaneeth:

    The customer also found that the setting value of the parameter USER_ADC_FULL_SCALE_CURRENT_A was controversial:

    In instaSPIN's User’s Guide page 238~239, The value of this parameter is calculated as follows:

    But in the hardware schematic of TMDSHVMTRINSPIN, the value of Rshunt should be 0.02Ω instead of 0.01Ω in the formula.

    So, does he need to change the value of USER_ADC_FULL_SCALE_CURRENT_A from 

    #define USER_ADC_FULL_SCALE_CURRENT_A        (19.89)    // Calculated value when Rshunt is 0.01Ω.

    to

    #define USER_ADC_FULL_SCALE_CURRENT_A        (9.94)      // Calculated value when Rshunt is 0.02Ω.

    ?

    Best regards,

    Green

  • 0 in reply to Navaneeth Narayanasamy
    TI__Expert 4490 points

    Hi Navaneeth:

    May you help answer the customer's question again?

    Best regards,

    Green