Battling severe voltage sag on a 48V AMR under peak torque. How do you stop your servo drives from throttling?
Hey everyone, looking for a sanity check on a heavy-payload AMR project (~700kg payload) running on a 48V LiFePO4 pack.
Whenever the robot hits rough terrain or accelerates suddenly, the transient current draw causes our battery bus to sag hard, dipping down to 35V-36V for a few hundred milliseconds. Our current "industrial-grade" servo drives are losing their minds under this sag. We are hitting under-voltage faults that trigger random emergency stops, massive thermal spikes inside our sealed IP65 wheel hubs as the drives draw more current to compensate, and mushy velocity control right when we need tight torque response.
We’ve debated adding a bulky buck-boost regulator just to keep the drive logic stable, but it kills our payload-to-weight ratio.
For those building battery-powered platforms that survive high-torque transients, are you over-specifying the battery pack to stop the sag, or switching to drives with ultra-wide input voltage ranges? Also, how do you handle the thermal overhead in a sealed housing? Do GaN-based or ultra-high-efficiency drives actually solve the heat issue at the source?
Trying to avoid a massive chassis redesign just to fit a bulkier cooling system. Any advice?