Electric Unicycle Project - Brushless Motor Controller?

Thread Starter

joe426

Joined Aug 11, 2009
39
I'm building a self balancing unicycle which uses this brushless hub motor (click hub motor on the left column). For balancing purposes, I need to be able to rapidly move the wheel forwards and backwards.

I've researched a wide variety of controllers, but after posting on an electric vehicle forum, I learned most commercial controllers have safeties in them which prevent forward and backward movement.

I still have yet to find one capable of the fine motor control described above. Any leads/advice would be greatly appreciated. I'd prefer one with regenerative braking, but at this point I'll take anything.

Thanks!
 

kubeek

Joined Sep 20, 2005
5,732
The first motor you linked has built-in controller. You will most likely have to build one by yourself, so you should find a bare motor wihtout it.
 

Thread Starter

joe426

Joined Aug 11, 2009
39
The first motor you linked has built-in controller. You will most likely have to build one by yourself, so you should find a bare motor wihtout it.
I actually ordered a version without the built in controller because the built in controller is 1) notorious for overheating and 2) made for electric bikes (constant forward motion, not quick forward-to-backward control)

have you looked at brushless servo drives like whats used in cnc machines?
No, do they make ones large enough to handle 44v @ 25A?
 

kubeek

Joined Sep 20, 2005
5,732
I actually ordered a version without the built in controller because the built in controller is 1) notorious for overheating and 2) made for electric bikes (constant forward motion, not quick forward-to-backward control)
I suppose it is a three-phase brushless motor, right? It shouldn't be hard to source a driver to it for this voltage and current. To make the unicycle work you will have to build your own controller anyway, but the driver will take care of the power electronics.
 

strantor

Joined Oct 3, 2010
5,330
No, do they make ones large enough to handle 44v @ 25A?
Before I go much further, when you are talking about a hub motor (I know what an ebike hubmotor is) I'm thinking the motor is parallel with the ground; spinning in free air; The "self balancing" gyroscopic thing. Not a traction motor that pushes against the ground. Am I correct?
 

Thread Starter

joe426

Joined Aug 11, 2009
39
I suppose it is a three-phase brushless motor, right? It shouldn't be hard to source a driver to it for this voltage and current. To make the unicycle work you will have to build your own controller anyway, but the driver will take care of the power electronics.
Yes, it's a 3 phase brushless motor. Do you have any recommendations on a driver?

Before I go much further, when you are talking about a hub motor (I know what an ebike hubmotor is) I'm thinking the motor is parallel with the ground; spinning in free air; The "self balancing" gyroscopic thing. Not a traction motor that pushes against the ground. Am I correct?
No, it pushes against the ground. I'm building a DIY version of the SoloWheel.
 

Thread Starter

joe426

Joined Aug 11, 2009
39
Here are some links to BLDC motor control ICs
Thanks for the links. Those OnSemi chips seem to be the ones everyone is using. Basically, what I'm hearing from everyone so far is that I need to build my own motor driver and brain. Looks like there is no way around it :/
 

Mandrake90

Joined Nov 23, 2016
1
Thank you guys for all these tips. I'm trying to design and build my own self balancing unicycle and I need to find a good brushless hub motor. This topic helped me a lot ;).
 
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