Recent content by sa2tms

I haven't bought anything yet. Right now I'd like to get a feel for what the Husqvarna system is like, if anyone's RE'd the protocol etc.

Hi. Recently I've been looking at Husqvarna's electric tools like chainsaws and noticed that they use Anderson PowerPole connectors (PP45 as far as I can tell) and I'm wondering if anyone knows what the pinout is? There's four PP45 connectors and the outermost two are obviously for power. The...

I'm doing exactly that. See the blog post I linked :) Still, first-party information is way better than trying to RE and hack something together. Had I found the Phylion battery manual earlier then a lot of my RE effort would not have been necessary. It also had some errors. edit: My RE'd stuff...

Hi I've been poking at the Joycube series of ebike batteries after one of mine was stolen and I discovered I can't just feed the bike 42V to run it. The display boots and shows an error code. I can turn on the light but the motor will not turn. Turns out the brain box in the bike needs some...

Aha, "resonant gate drive" are the magic words to search the literature for. Thanks :] Seems gate drive losses indeed start to dominate as switching frequencies go up. Good to see my mental model is sensible at least. Dumping enough charge into the gate to get past the Miller region as fast as...

di/dt? Not dV/dt? As I understand it the main limit to switching is the resulting dV/dt on the gate potentially causing damage. Seems most drivers use a constant voltage + series resistor to the gate. So gate current drops as gate voltage increases. Plus a long time is spent in the Miller...

This I've anticipated. I have a potentially very clever or very stupid idea for reducing gate drive losses that I'm going to post so no asshole goes and patents it: bounce the gate charge to/from an inductor. Use this inductor both for charging and discharging the gate. Don't bother with a gate...

And the Octave code for anyone interested: % Voltages to derive currents for VI = 0:0.01:1; VI2 = 0:0.01:1.15; VM = 0:0.01:1.5; % IXXK110N65B4H1 model function V = v_igbt(I) % Mostly linear model with an exponential dropoff toward 0V @ 0A % Kinda stupid, but seems to follow Fig. 3. Output...

Hi, first post on here. Got wind of this place existing from marcos' VESC variant being featured on Hackaday. Anyway, a thought struck me the other day: IGBTs are good for higher currents due to their limited voltage drop. But there is also an almost constant bias to this drop, which is a...