Part Number: TMS320F28027F
Other Parts Discussed in Thread: DRV8353
Hi,
We are controlling a 3-phase motor with F28027F + DRV8353S.
Today our “over-current” check is very simple: we monitor Iq_ref (q-axis current command) and trigger a fault when it is over a threshold for N cycles. We would like to use a more standard / recommended method.
Could you please advise on the following?
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Recommended over-current protection
What is the best practice for this combination?
Is it recommended to use DRV8353S OCP → nFAULT → F28027F ePWM Trip-Zone for fast shutdown, and use ADC current (Id/Iq or phase current) only as a secondary check? -
IQ_FULL_SCALE_CURRENT/ADC_FULL_SCALE_CURRENT
Our project uses auto-generated values:
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IQ_FULL_SCALE_CURRENT = 23.5 A -
ADC_FULL_SCALE_CURRENT = 47.18 A
Can you confirm what these parameters mean and how we should calculate the correct values from shunt resistor / amplifier gain / ADC range?
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Current offset calibration (Offset Current)
When we enable offset current calibration, the motor runs much smoother, but calibration takes about 5 seconds.
Is it OK to run this calibration only once at power-up and keep the offset value fixed during operation?
What is a typical recommended calibration time / sample count? -
Unused pins setting
Some GPIO/ADC pins are not connected on our PCB.
What is the recommended firmware setting to avoid noise (e.g., input with pull-up, output, analog mode, etc.)?
Thanks,
Conor
