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DRV8308EVM: Trapezoidal drive

foras foras
Prodigy 125 points
Part Number: DRV8308EVM
Other Parts Discussed in Thread: DRV8308

We are going to use drv8308 for a blower driver. We connect motors as show in their datasheet, enable EVM board, give PWM. According to motor behaviour(either rotates fine or jitters) we choose halpoll 1 or 0 and then adjust Advance parameter to get  a trapezoidal shape phase voltages (which also reduces current reading).

The problem is we are getting different results for different motors. Even though we have seen the phase voltages are trapezoidal, we do not get a good performance for some blowers ( not good because flow and pressure readings does not match their datasheet). 

For example micronel blower data sheet we suppose to have 400 l/min flow but we read 160 l/min.(The problem is not specific to this motor)

dataseet http://www.micronel.com/uploads/tx_micronel/U71MX-tec.pdf

We have tried four different blowers and 2 of them we get readings which matches datasheet and 2 of them does not. What can be the reason for this? How to resolve this issue?

We have also tried sine commutation and the problem remains.

  • 0
    TI__Expert 4435 points
    Hi Foras,

    I don't know if I am understanding you question correctly, I apologize.
    Do you have 4 units of the same motor and 2 not working as expected?
    or 4 different type of motors? If the latter, what is the difference between the motors?
    If they are all the same type? have you confirmed all the connections/leads are the same across them?
  • 0 in reply to Luis Riveros
    Prodigy 125 points

    Hi Luis,


    Thank you for your reply. We have 4 different motors. 4 of them is working but the main problem is 2 of them cant reach their performance criteria. Also we measured the rpm of them. Rpm value that we measure is same as datasheet but the air flow is half of the datasheet. For other 2 motor we can get the same performance with the datasheet values.

    So What can be problem ?