Help programming Sabvoton 7245 and XOFO 175 hub moto

hipur

1 mW
Joined
Apr 1, 2022
Messages
16
Location
Sao Paulo
Hello,

I'm trying to upgrade from a 25A controller to a Sabvoton 7245 from RisunMotor. I'm running a XOFO 175 750w motor that according to their technical specs has a 120 hall angle.

I've tried all six possible phase wires connections, three did spin the motors and three didn't as expected.
From the three that worked,had 305, 63 and 188 when running hall test. Only the setups that returned 63 and 188 also worked when setting hall angle to 120 manually, so I've already discarded 305 setup as a possible combination. The setup that returned 188 did some strange noises when in WOT, so I'm assuming that it was a false positive.

That let me with the setup that returned 63 as a hall angle, which also works setting angle to 120 manually. However, as soon as I put load on the bike and try to accelerate, it stutters with a impact driver noise on either angle setting, however after getting past 13mph it just seems to run smooth, and current draw seems to be reasonable.

My motor parameter in the app is set to 1000 and changing any other settings have no impact on that no power stuttering start. Does it make sense to try other hall sensor connections until I can get self test to return 120 angle? I'm very new to the ebike universe and did look around some topics, but couldn't come to any viable solution. :(
 
So I did all 36 possible combinations, ended up with 6 viable combinations for spinning with 120 hall angle, but none was smooth.

From the 6 possible positives, I've ran the Sabvoton hall angle test to see what values they would return, here's what I've got:


⚠️ Positive #1
Motor:

| Controller | Motor |
| --- | --- |
| Yellow | Green |
| Green | Blue |
| Blue | Yellow |

Sensor:

| Controller | Motor |
| --- | --- |
| Yellow | Blue |
| Green | Yellow |
| Blue | Green |

**Hall test angle:** 183



⚠️ Positive #2
Motor:

| Controller | Motor |
| --- | --- |
| Yellow | Yellow |
| Green | Green |
| Blue | Blue |

Sensor:

| Controller | Motor |
| --- | --- |
| Yellow | Blue |
| Green | Yellow |
| Blue | Green |

**Hall test angle:** 63



⚠️ Positive #3
Motor:

| Controller | Motor |
| --- | --- |
| Yellow | Green |
| Green | Yellow |
| Blue | Blue |

Sensor:

| Controller | Motor |
| --- | --- |
| Yellow | Yellow |
| Green | Blue |
| Blue | Green |

**Hall test angle:** 303, doesn’t spin



⚠️ Positive #4
Motor:

| Controller | Motor |
| --- | --- |
| Yellow | Blue |
| Green | Yellow |
| Blue | Green |

Sensor:

| Controller | Motor |
| --- | --- |
| Yellow | Green |
| Green | Blue |
| Blue | Yellow |

**Hall test angle:** 63



⚠️ Positive #5
Motor:

| Controller | Motor |
| --- | --- |
| Yellow | Blue |
| Green | Green |
| Blue | Yellow |

**Hall test angle:** 303, doesn’t spin



⚠️ Positive #6
Motor:

| Controller | Motor |
| --- | --- |
| Yellow | Green |
| Green | Blue |
| Blue | Yellow |

Sensor:

| Controller | Motor |
| --- | --- |
| Yellow | Yellow |
| Green | Green |
| Blue | Blue |

**Hall test angle:** 63

Honestly I couldn't come to any conclusion and the bike still not smooth when with any load on any given hall angle on all possible positives. I really don't know what else to do right now... :cry:

If I plug in the original controller it just works as it should, so I'm assuming phase and hall wires are okay.
 
I've seen that there are some SVMC 7245 that are for 180 phase angle. I'm afraid I might have one unit. Is it possible to change that eletronically without opening the motor and mecanically changing the sensors position? I've seen cables that change from 60 to 120 and vice versa but couldn't find 120 to 180 or 180 to 120... I'm kinda in a limbo right now.

EDIT: did a little research and it seems that all their V2 SVMC controllers are labelled as FOC 180 controllers but work with 120 motors. Gone from nowhere to nowhere...
 
Hello!

I'm trying to configure a FOC controller to my fat hub motor.

Right now I'm having a very rough start when there's load on the motor, but after a while the current loop stabilizes and I get a TON of torque and smooth riding, I gain speed and everything seems like a dream coming true.

Without load the motor spins without any of this simptoms, but with load everything is f'd...

I'm quite new to this world, so I'm learning as problems appear. When starting with load on bike, I need to throttle and let go like two or three times before I get a smooth acceleration. Usually what happens when I WOT from a full stop is that as soon as the motor starts to increase the torque, something stops it and it just seems like a impact drill, if I keep on WOT eventually everything smoothes out. A faster way to smooth things is to let go the throttle and WOT again a couple of tries as explained before.

If I limit current I can get a much smoother start (only tested alone in the bike), and while still moving I can increase current and still have a smooth ride, but I need that high torque start because 90% of the time I ride with another passenger, and my city's bike paths has lots of street crossings and steep parts, so a lot of stopping-starting, and it is a PITA to keep chaing "e-gears" all the time.

The only PID parameter I can adjust is Kp, I'm using a MQCON SVMC-M 7245 adjusting everything via their bluetooth app. Unfortunately it didn't came with USB cable so there's no way to use a computer with it. I did order a RS485 USB controller and will solder the other end to a USB-A plug to see if it works, but that only arrives at the end of the week.

Recommended Kp for 14inch motors is 299, for 10 inch motors is 999. I'm assuming that it has something to do with stator diameter. My SOFX motor (made by XOFO) has a stator size of 150mm approx. (5.7 in), so plotting some curves I come around 1500-1900 for the Kp. Did some tests and the drilling does get a little bit better specially with Kp around 2000-2100, but without drilling it introduces a loud whinning noise and after taking off somehow better, the current loop hits some "walls" (I assume steady-state error reduction is still working out) a few times before smoothing out.

If I set Kp too low (below 150), I get overcurrent error. My current phase current limit is 125A and I plan to run with a max of 40A rated DC current (that's my BMS limit).

I'm really without north here and my knowledge about PID and FOC controllers is very limited to find a reasonable solution.

Thanks!
 
amberwolf said:
Based on the symptoms before this problem occured, and those after, it sounds similar to when the wrong phase/hall combination is used, which often overloads the controller and motor, causing excessive heat especially at higher currents (like pushing the throttle hard suddenly, especially), and can cause vibration, shuddering, and other undesirable behavior before something actually fails.

Usually what fails is the controller, where FETs blow, but occasionally it is not a hard failure; it can even be the gate drives that partially fail, or just some FETs in a bridge, so its still "works" just not at full power.

Sometimes it's the hall sensors in the motor that fail, from repeated overheating.

Sometimes it's the wiring that fails, either the motor coil insulation from overheating, or the phase or hall wiring inside the motor cable (especially inside the axle where there is no cooling airflow).

Sometimes it is the connector that fails, where the shell or plastic mounting overheats and deforms, causing high-resistance connection.


Some of these are easy to visually check, and some require a multimeter to test. Some require opening things up to verify; some don't. Ebikes.ca - learn - troubleshooting has some good test documentation you can check out.
Since the Sabvoton is able to match different angles, is it still possible to have a wrong phase/hall combination if the motor spins?

On my setup I did all 36 combinations and did the hall test on all of them.
18 passed spinning forward with different angles (120 degrees difference between them)
18 passed spinning backwards with different angles

I'm having same problems as described in the first post of the thread, I need to take off slowly otherwise the motor vibrates hard.

I've tried testing with all 18 combinations that spin forward to see if the problem would be fixed with no success. So I'm assuming it has something to do with controller configuration and not a wrong hall/phase.
 
It probably is a controller configuration, but unfortunately I don't know what specifically it would be.

Most likely it has to do with phase current angle (which it may have separate settings for than the hall sensor angles), but it could even be the amount of phase currents--too high a current can saturate the stator and just create heat instead of doing work, and could interfere with the ability of the controller to read the phase currents, which would interfere with it's ability to control them.

Remember that "autotune" functions may not be perfect, and may require manual adjustments and experimentation.

FOC controllers require "knowing" what the motor's characteristics are, such as winding resistance and inductance, pole count, etc. If it doesn't know what those are, it can't control the phase currents correctly. So if it has an autotune that incorrectly detects these, you'd have to manually correct them to get better motor control.


You can also try running sensorless, if the controller has this option, to see if it is simply that it doesn't work well with the specific hall sensor configuration your motor has.
 
Back
Top