Power stage design for BLDC hub motor, 48 V, 22 Amps.
You may wonder why I would want to build a controller with such a normal power rating.
I am helping a high school team on their Shell Eco Marathon car.
The car uses a bicycle hub motor in the rear, it's a fairly common motor, 500W with hall sensors, and we have used a 10 cell Li-ion battery pack and a off the shelf 48V, 22amp Chinese controller.
With this combo we have won several competitions an set some new records.
Now I think Shell is trying to limit the number of electric cars in the field, so this year they have changed the rules, they are requiring the controller to be built by the teams.
No off the shelf controllers, no modified controllers, and to prove you built the controller the circuit board must bear the SEM, Shell Eco Maraton, mark.
I have Lebowski's chip on order, and I think we may also try using a MC33033 chip, from the Simple BLDC controller thread.
So from the forum I have a good idea on how the "brains" of the controller work, but I can't find any info on a simple power stage.
The threads I have found are for stages that a way overkill for what we need.
I need a efficient, relatively low power stage, that hopefully is simple so I can have the students build it.
The way we use the car follows.
We start from a dead stop, no pushing allowed, accelerate up to about 19 mph, then cut the motor and coast down to about 14 mph. We repeat this process for the entire race which is 25 minutes long.
We do 11 laps around the track, which is about 1 mile around. We may only use the motor two are three times per lap. At the end of the last lap we coast to the finish, brakes are never used.
Last year our best run used 47841 joules from the battery, and I think the maximum current draw was 12 amps.
Any guidance on component selection, general controller design, or links to existing designs would be a big help.
Thanks
Gene Young
You may wonder why I would want to build a controller with such a normal power rating.
I am helping a high school team on their Shell Eco Marathon car.
The car uses a bicycle hub motor in the rear, it's a fairly common motor, 500W with hall sensors, and we have used a 10 cell Li-ion battery pack and a off the shelf 48V, 22amp Chinese controller.
With this combo we have won several competitions an set some new records.
Now I think Shell is trying to limit the number of electric cars in the field, so this year they have changed the rules, they are requiring the controller to be built by the teams.
No off the shelf controllers, no modified controllers, and to prove you built the controller the circuit board must bear the SEM, Shell Eco Maraton, mark.
I have Lebowski's chip on order, and I think we may also try using a MC33033 chip, from the Simple BLDC controller thread.
So from the forum I have a good idea on how the "brains" of the controller work, but I can't find any info on a simple power stage.
The threads I have found are for stages that a way overkill for what we need.
I need a efficient, relatively low power stage, that hopefully is simple so I can have the students build it.
The way we use the car follows.
We start from a dead stop, no pushing allowed, accelerate up to about 19 mph, then cut the motor and coast down to about 14 mph. We repeat this process for the entire race which is 25 minutes long.
We do 11 laps around the track, which is about 1 mile around. We may only use the motor two are three times per lap. At the end of the last lap we coast to the finish, brakes are never used.
Last year our best run used 47841 joules from the battery, and I think the maximum current draw was 12 amps.
Any guidance on component selection, general controller design, or links to existing designs would be a big help.
Thanks
Gene Young
