Part Number: MCF8316A
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Combined with the above parameters and phenomena, we actually tried many sets of settings, but none had a significant effect. So we would like to know:
Hello, we are debugging the active brake function, using the MCF8316A chip. Using a brushless DC motor, 24V, the MPET test resistance is 0.78 ohms, the inductance is 0.215 mH, the back EMF constant is 18 mV/HZ, max_speed = 660 Hz, one pair of poles
Problems occurred during the test, and we ask for your help.
The first phenomenon:
Configuration: ACTIVE_BRAKE_CURRENT_LIMIT = 3.0A,
ACTIVE_BRAKE_BUS_CURRENT_SLEW_RATE = 250A/S,
ACTIVE_BRAKE_MOD_INDEX_LIMIT = 80%,
ACTIVE_BRAKE_SPEED_DELTA_LIMIT = 2.5%,
ACTIVE_BRAKE_KP = 6.5,
ACTIVE_BRAKE_KI = 1,
The speed decreases from 660 Hz to 230 Hz, enabling AVS and active brake, and the test waveform is as follows:
ACTIVE_BRAKE_BUS_CURRENT_SLEW_RATE = 250A/S,
ACTIVE_BRAKE_MOD_INDEX_LIMIT = 80%,
ACTIVE_BRAKE_SPEED_DELTA_LIMIT = 2.5%,
ACTIVE_BRAKE_KP = 6.5,
ACTIVE_BRAKE_KI = 1,
The speed decreases from 660 Hz to 230 Hz, enabling AVS and active brake, and the test waveform is as follows:
Channel 1 is the FG waveform, and it is set with only closed-loop output; Channel 2 is the phase current waveform（100mv/1.0A）.
QUESTION：
Why can the phase current reach 10A, and is not completely limited by the ACTIVE_BRAKE_CURRENT_LIMIT? (Fault overcurrent)
Why can the phase current reach 10A, and is not completely limited by the ACTIVE_BRAKE_CURRENT_LIMIT? (Fault overcurrent)
The second phenomenon:
Configuration: ACTIVE_BRAKE_CURRENT_LIMIT = 2A,
ACTIVE_BRAKE_BUS_CURRENT_SLEW_RATE = 100A/S,
ACTIVE_BRAKE_MOD_INDEX_LIMIT = 70%,
ACTIVE_BRAKE_SPEED_DELTA_LIMIT = 2.5%,
ACTIVE_BRAKE_KP = 1,
ACTIVE_BRAKE_KI = 0.5,
The speed decreases from 660 Hz to 230 Hz, enabling AVS and active brake, and the test waveform is as follows:
Configuration: ACTIVE_BRAKE_CURRENT_LIMIT = 2A,
ACTIVE_BRAKE_BUS_CURRENT_SLEW_RATE = 100A/S,
ACTIVE_BRAKE_MOD_INDEX_LIMIT = 70%,
ACTIVE_BRAKE_SPEED_DELTA_LIMIT = 2.5%,
ACTIVE_BRAKE_KP = 1,
ACTIVE_BRAKE_KI = 0.5,
The speed decreases from 660 Hz to 230 Hz, enabling AVS and active brake, and the test waveform is as follows:
Channel 1 is the bus voltage 24V waveform; Channel 2 is the phase current waveform（100mv/1.0A）.
QUESTION:
Even with AVS enabled, why would the bus voltage still overvoltage (resulting in an alarm due to exceeding 32V)?
QUESTION:
Even with AVS enabled, why would the bus voltage still overvoltage (resulting in an alarm due to exceeding 32V)?
Combined with the above parameters and phenomena, we actually tried many sets of settings, but none had a significant effect. So we would like to know:
we really want to know :
- What is the exact relationship between these parameters?
- How should these parameters be adjusted to normally use the active brake to achieve rapid speed reduction?
Looking forward to your reply.
Sincerely
Eddie yao
