VESC 75200 Versus Votol EM-100

rbarrow

10 mW
Joined
Jan 3, 2021
Messages
23
Based on the shear effort of getting a Votol to work optimally, I had the idea of "re-braining" the Votol controllers with a small 4.12 VESC. There are a few issues in making this happen but the biggest issue is that Votol is not really a FOC controller. The early VESCs, like the 4.12 used only 2 shunts and worked with a simplified FOC scheme (alpha beta). With the exception of the newest Votol controllers, they use only one shunt and perhaps another voltage based sampler on one of the other two phases.

The Idea was based mainly on the fact that many people, including myself, believe that Votol makes good hardware. However, as I noted above, the holes start to form in looking at the old Votol hardware. For one, TO-220 MOSFETs are not great, even if they are Magnachip. The legs just cannot get the current through. The thin part of the leg, which is how all the older EM-100, 150, 200, and 260 are built, can only handle 50 amps. So, the EM-100 for example only has 3 FETs for each half of each phase. That is only 150 amps. The EM-150 has 4 FETs, that is only 200 amps. So, the max current of these drives comes down more to the mechanical properties of the TO-220 package than the FETs themselves. The lack of true FOC control is perhaps the reason why they controllers require so many parameters and tweaking.

The 4.12 version of VESC was their open source development solution. When Benjamin Vedder pulled the design for his own solution, Trampa, all the designs have been 3 shunt based, true FOC controllers. They also almost all use some form of surface mount FETs (granted most are Chinese) that have numerous legs and extremely high current capabilities with low RDSon currents. Aside from the heatsinks being a bit small (easily corrected with some mechanical heat sinking addition), I would say the layout and design is better (simple layout, short current paths, ect).

So, which one is better at powering your E-Bike or small go kart? Well, the Votol EM-100 offers 100 battery amps with a peak of 330 Phase amps (however, many are 300 amps) and the VESC 75200 does not provide battery amps but can also produce 300 battery amps. So, which one is better? I will test them both to see what the difference is. I know one thing, setting up the VESC will be significantly easier.

If you have done some testing yourself, please share some details. I have some 10 different controllers I have tested with a variety of motors. I try to stay in the budget space as I have lots of projects, not just a couple of meticulous creations. I don't have any of the new Votol controllers like the EM-100GTR that looks superior to the older EM-100s but I do not believe they are any easier to setup.
 
From personal experience and from what I've seen the newer 75200s with the phase filters and improved hardware layout are better. Some of the early ones have a dumb amplifier setup that introduces a lot of noise for no reason. They still are not exactly high quality hardware but do work for many applications. They still have a serious lack of high frequency filter caps (none) and the MPCBs are often badly warped so make poor contact with the cases. VESC is pretty good with dealing with many of these issues and depends heavily on how you are using it.

If you aren't trying to drive a very difficult to drive motor in hard conditions probably fine and that may even be unfair if you consider other controllers may not drive motors like that at all in FOC. If you need 300PA though just getting the bigger flipsky controllers is a better option, they don't cost that much more and pushing "good enough" grade hardware to it's limits is probably not wise.

Also I wouldn't say VESC is always easier to setup, sometimes it can be a pain to find the right settings but maybe crucially you almost always can get it working well even with challenging motors which may not be the case for other controllers. And you have to factor that the VESC will keep improving with new firmware.
 
Having worked extensively with VESC, it is certainly not a walk in the park but compared to Votol, it certainly seems that way. I think the main issue with Votol is the way the versions appear on the GUI interface and that they have made numerous upgrades to the software without changing the interface. So, you make changes that should solve a problem or improve performance and the thing just fails to repond in any way. The other part is the Calibration that almost no one is aware of. There is a group of hackers in the far east that likely know how to work around this and have collaborated to share insight and are making a business out of it (calling themselves "professionals"). That is the main difference between the two drives. Both are complicated, however, one at least is better understood and open.
 
Never used a Votol but that sounds about like what I've heard. I think VESC really needs better documentation but at least there is a lot of support out there. For motors that are not very hard to drive I think the trick is the VESC will probably run great right out of the wizard at a low to moderate power level but when you start cranking up the phase amps some motors require more tuning. I think some of this is due to crappy hardware with poor filtering but also some is just tuning.

And a few issues I've had are quirks of VESC which are either getting fixed, like the sensor to sensorless transition sometimes being rough, or are just down to the idea of VESC. And what I mean by that is it's a controller designed to drive any motor not pre-tuned for a certain type of motor, I don't even mean pre-tuned as in the settings I mean I think many controlers are deisgned to drive certain hardware and there are settings that are hardcoded to do that. What this means is the default VESC settings may not always be ideal because while it changes some things based on the motor type there are a lot of other settings that it's up to you to adjust if needed. Which I'm totally fine with I just wish there was some documenation to figure out what these are instead of trawling through the discord like I did.
 
Yeah, you are likely right. The V magnet shaped QS motors (QS90, 120, 138, 160) motors seem to be ideal for the Votol controllers. This might also be true for the large QS hub motors (QS205, 273). I have not played much with the VESC with hub motors, however, hub motor owners like the extremely high field weakening that is 200% in the Votol. I have not tested Field weakening with VESC.....yet.
 
Does the Votol have MTPA? If not I think that is kinda a deal breaker is you're using a high salience IPM motor (V magnets). I don't quite get why people like using that much field weakening on a hub motor, really should use an appropriate winding instead. Even with a high salience motor there are serious downsides to running so far beyond the no load RPM.
 
Yes, it does have MTBA but you have to have the custom software (Vino) that has all these parameters redefined appropriately. Some poeple have to take their hub bikes to 100MPH apparently. The Votol does have a lot of bang for the buck, it is just the software/support/versions that make everything difficult.
 
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