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Hello Qiurui,
Is this the same request as https://e2e.ti.com/support/motor-drivers-group/motor-drivers/f/motor-drivers-forum/1012180/drv8308-motor-debugging?
Thanks,
Matt
Hello Qiurui,
The DRV8308 requires the speed loop to be tuned to the motor, and we do not expect that the DRV8308 settings will work across different motors.
I need to review your settings to see if I can offer any suggestions.
Have you tried bypassing the comparator to see if performance improves on the second motor?
Thanks,
Matt
Matt,they are the same question.I have tried bypassing the comparator,However, the performance has not improved on the second motor.I also found a phenomenon that when the speed deviation is very large (estimated to be more than 30%), the lockn indicator of EVM board begin changes color, and it's the same when the speedth setting is 0.78% or 6.25%.
Hello Qiurui,
They may need to increase the SPEEDTH in order to have a wider tolerance for LOCK. If the DRV8308 drops out of LOCK then the commutation switches from SINE to TRAP.
Please take note that July 5 is the Independence Day holiday in the US. The team is out of office and will get back to you as soon as they return!
Thanks,
Matt
Hello Qiurui,
Those pins are to be used with an FG trace. If you do not have an FG trace, please leave these pins unused. You can look at www.ti.com/.../TIDA-00197 to see how it is done in that design.
See this image for an example of an FG trace on a motor:
Thanks,
Matt