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DRV8353RS-EVM: Instaspin-FOC using DRV8353RS-EVM - Resistance estimation does not match the motor specification

Part Number: DRV8353RS-EVM
Other Parts Discussed in Thread: MOTORWARE, DRV8353

Hello,

I am evaluating the Evaluation motor driver board DRV8353RS-EVM using a sensorless motor.

I followed all the steps in the technical documents. I copied the firmware files in the MotorWare folder, opened the Lab05b project, compiled and loaded the .out with the guicomposer.

I am able to run the motor only if I use the motor parameter values provided by the estimator. But those values are off by at least a factor of two and I make sure I use the Phase to Neutral value in a Y architecture. Using the motor parameters from the motor datasheet doesn't work and that for two different type of motors.

For instance, the motor rotor resistance value per the datasheet is 2.86 ohms. I enter a Rs value in user.h of 2.86 / 2 = 1.43 ohms. The estimator gives me a value of around 0.7 ohm.

I doubt it's a temperature issue since I get those values at 20C with a motor that hasn't run yet and besides the resistance should not change to that extend with temperature.

I even used the motor BLY172S-24V-4000 from Anaheim Automation with the pre-recorded parameters in user.h (matching the datasheet). The parameters doesn't match the estimation value from Instaspin-FOC either.

Please let me know if you have a solution or explanation for this behavior. My motor does run but I hate when I can't explain why. It could end up being dangerous for my application.

Thank you very much for your help.