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keshuaixu / dvrk-s-pwm

H-bridge motor drivers for dVRK-S
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extra inductance in ESPM for motor 4 causes resonance #33

Closed keshuaixu closed 2 years ago

keshuaixu commented 3 years ago

ESPM has 10 nF to GND indutance on motor 3 and 4 but not on 5, 6, 7. Combined with 100uH series inductance, they resonate at 150kHz. When driven in the direction that makes the current sense resistor on the high side, the resonance current gets picked up by the current sense circuit.

Hacky solution is to short the inductor on the current sense resistor side.

In next build, experiment with 10-20 uH inductor on the resistor side, maybe for all channels.

keshuaixu commented 3 years ago

SRP1770TA-150M f = 410936.29518488[Hz]