• State
  • Locked Locked
  • Replies 3 replies
  • Subscribers 82 subscribers
  • Views 683 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

CCS/TMS320F28069: Question for offset calibration

Chien ting wei
Prodigy 90 points
Part Number: TMS320F28069

Tool/software: Code Composer Studio

HI:

I'm new to the motor control,

i've finished identified my motor .After reading the LAB and USER GUIDE ,i still cant understand why i need to do the I_offset and V_offset.

Is this step has great influence to the performance of motor?Is the value vary to different driver or inverter?

regard

  • 0
    TI__Guru** 109820 points
    As descripted in Section 4 of spruhj1g (InstaSPIN user's guide), these two offsets are for ADC current/voltage offsets for U/V/W 3 phases, this is one time hardware dependent value which can be calibrated at run time. The offsets is critical for motor running, especially for low speed performance.
  • 0 in reply to Yanming Luo
    Prodigy 90 points

    thanks a lots~

    does that means when spinning motor at low speed ,the current or voltage may be too small to be detected or unstable?So,using the offset to make it better?

  • 0 in reply to Chien ting wei
    TI__Genius 17175 points
    Too low of voltage/current feedback levels make it impossible to accurately sense, leading to loss of information about the back EMF. The offset is different, it is information for InstaSPIN to subtract/add a static offset to the ADC conversion value to account for any hardware biasing of the feedback signals. If the feedback is too small to be reliably sampled, the offset will just show up as a static bias, which can lead to error but does not change the level of the sampled signal otherwise

    Sean