Get real world experience and user feedback on the electric bicycle products.
squigdawg 1 µW
- Posts: 3
- Joined: Dec 17 2018 2:39am
Like Shredkid and others on this thread, I'm also experiencing the Instantaneous Overcurrent Fault with BBSHD and Phaserunner. It happens almost every time during hard acceleration and I’ve tried everything I can think of with no luck. With a 52V battery everything runs great and no faults using the Kp=1 Ki=10 values that others have recommended, but at 78V (21S) I can’t make it reliable.
Here are some things I’ve tried:
- Recommended PLL bandwidth = 2.5, current regulator bandwidth = 2500. This results in a “judder” that I assume is the controller with too much gain oscillating around the setpoint.
- Auto-tuned with both 4 and 88 pole pairs (77 rpm/V vs 3.5 rpm/V due to ~22:1 gear ratio to the cranks). No difference either way.
- Lowered max phase amps from 96 to 50A (50A torque is much gentler but still faults)
- Arielpixels’ solution here: Keep voltage at 52V, use CA current limit and throttle ramping. Also, set current bandwidth and PLL to 0. Then set Ki and Kp manually. Kp = autotuned 118, lowered Ki to .2. Still faults.
- Tried the Beta v1.1 Phaserunner software with no difference, then went back to current version v1.0.5.
- Sensorless start. I didn’t give this a fair try because I don’t like the hesitation on start interfering with wheelies and starting on steep hills.
- “Torque Up Ramp” left at default 200ms. Did not want to increase this since faster start response is the goal.
- Manually tuning Kp and Ki with Current Regulator Bandwidth set to 0. More details on that below.
I see on the Developer tab (and included BOD.json file), Instantaneous Over Current Trip Threshold (address 29) is set to its maximum value of 116 Amps. I *think* what is happening is the poorly tuned PI controller (due to incorrect Kp and Ki values) is overshooting the 96 Amp target and tripping the fault. The graphing feature on the Dashboard tab doesn’t ever show the overshoot past 96 Amps, but I think the polling rate is just too low. Anyway, here are some observations that don’t make sense:
- When using the “current regulator bandwidth” mode without manually tuning Kp and Ki, the advice is to *increase* current regulator bandwidth if you are getting instantaneous over current faults. But that increases both Kp and Ki making the current response more aggressive causing the over current fault more easily. What am I missing here?
- When manually tuning Kp and Ki, Kp behaves as expected: Kp too small and motor current doesn’t reach the max. Kp too large causes oscillations and noise from the motor. Ki, however, seems to be much too sensitive. With Kp=0, the very first increment of Ki=0.0625 (Ki register is scaled by 16 so quantized to increments of 1/16) causes aggressive motor current ramp to max in just a few milliseconds. It’s not clear what rate the current regulator is updating at but I would expect you could set Ki to the smallest value and get a nice slow ramp up of motor current over several seconds.
- If I set a small current regulator bandwidth like 20 radians, it calculates small Kp=0.01 and Ki=2.44 values that you can see in the greyed out text boxes and the motor current response is very gentle. However, setting current regulator bandwidth to 0 and manually entering those same Kp and Ki values gives a very different aggressive motor current response. Why is the response so different if Kp and Ki weren’t changed? Could this be a bug that helps explain why the overcurrent fault keeps happening when using a manual Ki setting? I'll try asking Grin support and post back if I make any progress.
Last edited by squigdawg
on Aug 03 2019 6:24pm, edited 2 times in total.
Shredkid 1 µW
- Posts: 2
- Joined: Jul 12 2019 7:12am
I tried it with the 1.1 i got thru autotune with 3100 5.1 rads but it was not running like before still had hall errors I ordered a new core to see if that is issue the unit was pulling 2032 watts before now I cant get more than 400 watts I think i might have damaged the solder on the hall board but figured i will swap the core and try a fresh auto Tune Grin is not responding or helping kinda surprised but par for DYI stuff.
Surly BBSHD/Phaserunner v2/CAV3 52v,66v,88v
andrebandre 10 W
- Posts: 99
- Joined: Dec 02 2015 8:17am
I didn't fare any better trying to get the PR to work with a CYC motor.
I have 2 motors, i will try the second one maybe i get lucky.
squigdawg 1 µW
- Posts: 3
- Joined: Dec 17 2018 2:39am
Grin tech support suggested trying the new "virtual electronic freewheeling
" feature to ensure the BBSHD motor stays engaged with the drivetrain and is not allowed to suddenly catch up with the one-way clutch causing a big spike in motor current. That makes sense, and seems to be what ERT is doing with their BAC800 BBSHD kit as seen as the motor continuing to run after throttle is released in these YouTube videos here
The feature seems to be working and prevents some freewheel clutch related overcurrent faults as the motor keeps gently pushing after throttle is released until the wheel is forced to stop. Unfortunately it doesn't help with the faults that happen under smooth full power acceleration. What did work, however, was lowering the motor "Max Power Limit" to 3250W
. Anything 3300 or higher will fault under acceleration. Originally 6000W was set with the intention that the 50Amp battery current limit would take over. All other settings match the Jul 20 screenshots above, except Kp=1 and Ki=10 were put back.
I would like to understand why Max Power Limit can't be higher (I was expecting 88V x 50A = 4400W) but it wheelies easily now and is finally rideable and much faster than the Bafang controller so I'm happy!
sleepless 1 mW
- Posts: 16
- Joined: Nov 27 2017 3:39pm
I also have the Phaserunner and BBSHD setup since yesterday but I have a strange issue: even though I have more power now, the rotation speed of the motor is decreased in comparison to the stock controller (I think). Normally I could go up to 42 kph in third gear but with the phaserunner I am way slower in third gear. Does anybody have an idea what I should check / change?
Andre1985g 1 µW
- Posts: 1
- Joined: Jul 28 2019 7:15pm
Hello, I am André and am new here...
After working on my BBSHD +Phaserunner v.2 +Cycleanalyst 3.1 in frustration
for 2 days now and I can't manage the engine to rotate normally.
PLEASE HELP ME
If I wanted to ask if someone is so nice and could upload a profile for Phaserunner and a profile for the Cycle Analyst with which the BBSHD would at least work normally.
I use a 14S7P battery with 21,000mAh.
that would really help me