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VESC 75/300 current noise / losing sync?

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ezonca
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VESC 75/300 current noise / losing sync?

Hello,

I'm using the VESC75/300 in an application doing braking (regen) for an extended period of time.

I'm using a low-inductance motor with BLDC at 20-40KHz and we have good, albeit electrically noisy, performance.

When we try to run with FOC, we encounter issues where the current measured on the motor and the battery start to jump around significantly after we've been in regen for maybe a minute or so. This was delayed by dropping frequency from 48Khz down to 38kHz and enabling Sample in V0 and V7, but the issue still occurred. Is the VESC losing sync with the motor? We have also seen similar performance with another low inductance motor driving in FOC mode--the VESC seemed to commutate erratically after the currents got noisy, and we lost control of the motor.

foc_38Khz_noisy.PNG

Thanks for your help!

e-biker
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Joined: 2017-09-11 10:16
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Hi,

Motor could be loosing sync due too change of it's resistance then it heats up. You should add a temperature sensor to it and enable temperature compensation (FOC -> sensorless -> Temp Comp) or more simple way is jus to increase measured resistance by a few percents until it helps.

Martin.

benjamin
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Joined: 2016-12-26 15:20
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One known issue with the 75/300 is that is measures the flux linkage too high on some motors. Try decreasing the flux linkage with 5 - 50% and see if it helps.