Hello,
I am using a DRV8305 in 1 PWM mode without any sensors (BEMF).
For the regulation, I am using the cycle by cycle current method with the SOx outputs.
My problem is : the motor makes a ringing sound when It is accelerating and mostly when it is decelerating.
Current Shunt Amplifiers Config :
- Gain = 10V/V
- k = 4
- CS Blank = 500 ns
- DC_CAL_CHx : normal operation
- Current Shunt = 50mΩ
When I want to decelerate, I set the DAC1_OUT1 to 0 (0V).
However, SOx_Output cannot go under 0.825V, so the duty cycle of my PWM is equal to 0 during deceleration.
Also, during deceleration, the motor current is negative and Vbus is alterate (voltage overshoots around 5V depending of the setpoint).
Vbus = 24V when stable.
Here is the electronic schematic :
I removed C45, C46, C50, C51, C52, C53, R46, R52, R55, C34 and C55 on my board.
R57 and R257 are shorted.
R75 replaced by a current shunt of 50mΩ
A third capacity of 330uF is on the Vbus but not appearing on this schematic.
BEMF is stable and well centered.
Best regards,
