DRV10970: Trapezoidal control 3-phase BLDC motor driver with integrated mosfet

Hi Sayali,

What do you mean it's getting worse at 100% duty cycle?

What mode do you intend to operate in? If CMTMOD is floating you will be operating in trapezoidal commutation (It appears you're operating in trapezoidal).

If you are unsure which mode to operate in see section 8.4.1, it covers Operation in Trapezoidal Mode and Sinusoidal Mode.

Thanks,

Michael

Hi Michael,

 yes we are operating in trapezoidal mode.

please check the waveform of phase current at 100% and 70% duty ,at 100% the waveform is getting curve in shape.

Regards,

Sayali 

Hi Sayali,

I'm in the lab now trying to replicate your waveform. I'll have an answer for you shortly. 

Thanks,

Michael

Hi Michael,

    Thank you for reply. we are also observing this same waveform upto 70% duty cycle but after that is start to get distorted  as shown earlier in my reply. do you have any suggestion for this or what specific we can check to find the issue.

Regards,

Sayali

Hi Sayali,

The only thing I can think of is to change the degree hall placement (with the CMTMOD pin) and see if this changes anything. Otherwise I believe the device is operating as intended. Keep in mind this is one of our oldest devices so it doesn't have a way to modify the parameters with SPI ect.  

Do you mind letting me know what the application is for? If this device doesn't suite your needs I can recommended another device. 

Thanks,

Michael

Hi Sayali,

If motor runs unloaded I would try to load it and check if there is any change to motor current waveform.

Regards,

Grzegorz

Hi Michael, 

  we were running slotless motor with this driver , does that is impacting this. Is this driver is suitable for both slotless and slotted motor.

we want to run this with blower.  can you suggest sensorless solution with same rating i.e (current upto 2 to 3A ,Voltage upto 24V and integrated configuration ).

 If we select any IC what is life of the product in general how many years as we don't want a situation that if we select something it becomes obsolete in near future

Regards,

Sayali

Hi Sayali,

There will be some back-EMF waveform difference between slotless and slotted motors, but this driver should be suitable for both options.

DRV10987 is an integrated sensorless motor driver with 28V max rating. Please see our FAQ DRV10x selection guide (LINK) for more details on the DRV10x portfolio.

We have a FAQ resource for TI end-of-life (EOL) and obsolescence policy (LINK). Please read these links and let me know if you have any questions.

Thanks,

Matt

Hi Matt,

  Thank you for details , we went through link and selected DRV10974 as we are looking for plug and play option and option which you have suggested i.e DRV10987 it is not plug and play option it requires programing right ?.

can you share your view on DRV10987.

Regards,

Sayali

Hi Matt,

  Thanks for clarification, we are ok if the operating voltage is upto 18V and DRV10974 is plug and play right .

Regards,

Sayali

Hi Sayali,

The DRV10974 does operate up to 18V with 20V abs max rating. This device does not have any EEPROM settings so it is easier to use.

Thanks,

Matt

Thanks Matt