BLDC motor controller help

W

wright100

100 µW
Joined
Nov 15, 2009
Messages
8
Hey Guys,

I am working on a project to build a hybried electric vehicle for a competition at my college. The vehicle is going to use three BLDC motors, one for a generator, one for a drive motor, and one for a regenerative braking motor. The problem I am running into is that the efficient BLDC motors in my power range (200W-500W) are also sensorless. And for the generator and regenerative braking motors I cannot find BLDC motor controllers that do regenerative braking sensorlessly. Does anyone know of any controllers that are capable of this? Or does anyone know of any brushed or brushless DC motors that are around 93% that in the case of brushless have hall-effect sensors? I have found numerous controllers that can do sensored regenerative braking.

Thanks.
Nate
 
Okay, stop right there really quick. Why do you need three motors all doing different tasks?

Can you explain your reasoning for having a "generator" motor?

And you do not need a separate motor for driving the vehicle, and regen. You can do all of this with one motor. The only reason for more than one motor, is if you hooked them all up to do the same task, and share the load.

Try and explain your project a little better please, and maybe we can help you out a little more.
 
Ok sorry about that I can give you a better explanation.

I am part of a competition team at my college called SuperMileage. We build high efficiency vehicles and then "race" for the highest fuel efficiency. My school competes in the Internal Combustion engine division. This means that all the power needed to run the vehicle has to come from a the gasoline fuel. In the past my school has used a setup where we use the ICE to accelerate the car to around 30 MPH and then we coast down to like 8 MPH before burning up again. This allows us to maintain around 15 MPH, which is required to finish the race on time. The problem with this strategy is that the power lost due to aerodynamic drag is a function of velocity cubed. Therefore when we are traveling at 30MPH we have much higher drag losses than are really necessary. Ideally we would like to keep the car going at a constant 15MPH. However, it is not efficient for us to constantly be turning the ICE on to keep the car at 15 MPH therefore we would like to go to an electric system.

Because all power has to come from the fuel we need to have a electric generator that is powered off the ICE. I believe this will require it to be an entirely seperate motor from the other motors on the system. We would like to run the generator at about 500W because that is our estimated "sweet spot" on our ICE. In order to use the BLDC motor as a generator we would need to use it as if it is regening. The power from the generator will be transfered to a bank of ultra capacitors which will be sized to hold enough power for one lap of the race. We have to use ultra-capacitors because they can be discharged to 0W. This proves that we are not cheating and using pre-charged batteries or something.

Powered off the ultra-capacitors will be a drive motor. It takes approximately 50W to maintain 15MPH on a flat course. Going up a 1% grade at 15MPH with a 25MPH headwind requires about 275W. Therefore we are looking for an efficient drive motor power range of about 200-300W. We will probably use some very small burn coast strategy so that it requires between 200-300W to drive the car instead of 50W.

The problem is that the down-hill part of the course is much steeper than the up-hill. Therefore we need to be able to regen about 750W. In addition, the ability to regen is based upon the voltage of the ultra-capacitors, while the voltage of the motor while regening is a function of the RPM of the wheel. Therefore, we are thinking that we will need a different gearing scheme for the regen compared to the drive motor. The other option is we could boost the voltage coming off the regen to the voltage needed to charge the bank of ultra-capacitors. This I believe would allow us to use one motor for driving and regenerative braking as long is it is efficient at both 200-300W and around 750W - 800W. Anyhow the problem I am having is my inability to find a motor controller that is capable of 4-Quadrant operation without the use of sensors. And I am trying to avoid having to add my own sensors because that seems like it would be a bit of a pain. However, we are looking into that because we havn't found many better options at the momment.


Our best motor option to date is the NEU motor.
http://www.neumotors.com/Site/1900_series.html
We are looking at the 1915 225-3Y in particular.

We are also looking into motors made by ThinGap
http://www.thingap.com/index.htm
Because they are in our power range and also very efficient. I am waiting for information on them from the company. These motors do have sensors.

Nate
 
Also, it is often quite easy to add hall sensors to a sensorless motor (there are threads around here showing how to do it for some of them).
 
Does anyone here have an experience adding hall-effect sensors to NEU motors? I saw that quite a few people have used the NEU motors for other applications.

Nate
 
I do not see using ultra caps as a good solution for your use, though I know why you would want to. I think a nice small a123 pack is a good choice for you for temporary energy storage.

What is the size, and power your gas motor can put out, and how much fuel can you use?

I know the infinion controllers have regen built in. It is not perfect, as it isn't variable braking power, but it does work well on my bike. To enable regen, you just short the brake pads that are for the ebrake, and it boosts the voltage upto the battery voltage, and puts the energy back into the batts.

I think the regen braking power available is partly determined by the shunt resistance, so you could possibly make it so when you turn on regen, you also lower the shunt resistance to get the required braking power. Just an idea, i've never tested it, and there may be an easier way to adjust the regen power.

I also think it's a good idea to add sensors to the motor, though i've never done it my self. Shouldn't take more than knowing where to place them, a dremel, some epoxy, and wiring them up.
 
Yea, we really wanted to use A123 cells. I did a lot of research on them and they seemed to be the best battery solution. However, when we emailed SAE (who is putting on the competition) they said we have to prove that our system has zero energy when it starts. We offered to bring a watt meter to prove that there is more energy in the system when we end than when we started, but they said no. Therefore, we have to use ultra-capacitors because of their ability to be entirely discharged. If I were to do this project on my own (without competition rules) I would use A123 cells.

It is difficult for me to put my finger on the the power output of our gasoline engine. I believe that stock it is around 2HP. However, these engines are heavily modified to achieve higher gas mileage. Therefore, that number is not really that accurate. I am hoping in the next few weeks the team will get the engine on a dyno and we will have an exact number as to the highest efficiency point of the engine. Our guess is based upon conventional curves we have found for engines.

I have done a few searches on this board and I keep hearing a lot about these infineon controllers. I actually almost bought a motor control kit from Infineon but went with one from MicroChip instead. Are these motor controller kits what you guys are talking about? Could somebody link me to the controllers that everyone is talking about?

Yea, I am seriously considering adding hall-effect sensors to the motor. We have a NEU motor on order (should be here in about two weeks). I want to see if it is as efficient as their motor calculator claims it is going to be. If at that point I havn't found a solution to my controller issues I will probably look into adding sensors.

Nate
 
I would keep trying to work with the competition organizers about using batteries instead of ultracaps. Ultra caps are REALLY expensive for the amount of energy storage you get. That is a little ridiculous if they will not let you use a battery!

And there are TONS of threads on the infinion controllers.
Here is one of the first ones: http://www.endless-sphere.com/forums/viewtopic.php?f=2&t=5713
This is for Method's INSANE controller: http://www.endless-sphere.com/forums/viewtopic.php?f=2&t=10312
A tech thread for the infinion: http://www.endless-sphere.com/forums/viewtopic.php?f=16&t=7361
Info for programming: http://www.endless-sphere.com/forums/viewtopic.php?f=16&t=7531

You gots some reading to do!!! :twisted:
 
Thanks for the links. My biggest question is where is everyone getting these controllers from? I am assuming that Infineon does not make the entire controller, but rather just the Microprocessor on the board.

I will begin reading those pages and see what I can find out.

Nate
 
You can get the controllers by contacting Keywin (ecrazyman@gmail.com), or e-bikekit.com sells them. I'm sure there are more sources, but that is what comes to mind
 
ICEwrench: We actually are planning on using the ICE to turn the generator.

Tostino: Thanks for the store idea. I see one main controller, which is the E-BikeKitâ„¢ 36V 22 Amp Intelligent Motor Controller. Does anyone have any experience with this controller? We would want to operate at around 50V bus voltage. It says it can handle a 48V battery back, so it seems to be ok in that regard. Has anyone implemented regen with this controller?

Nate
 
That is a standard 12fet infinion, which is the same as mine. All it takes to enable regen is shorting a pad in the controller to ground. Just solder a wire between the two pads, and regen is enabled. Easy as that.
 
A sensored hub motor. I push 70+ amps through it without issue at 51v nominal. However, I am waiting for new fets to come in from Methods for some higher currents.

It is a great controller for my needs. I am also kinda interested in how to modify the regen to hit harder (and possibly have somewhat variable braking power). I use regen for the majority of my braking, and only touch my actual brakes if completely necessary for quick stops. I think putting the effort into placing hall sensors in the motor is worth it.
 
I contacted NEU motors about our motor and asked them to install hall-effect sensors. They agreed to do that for us, so that helps me solve the problem a lot.

We wouldn't need anywhere near 70 amps. In fact I don't think we would hit much past 20 Amps. How do you control the voltage of the regen on your controller? This is a slight problem for us because we are using ultra-capacitors. As they discharge the voltage decreases significantly. Unlike a battery whose voltage remains relatively constant and then drops like a rock.

Right now I am considering this controller.
http://www.electrocraft.com/products/drives/EA47/

I am hoping to call them up tomorrow and ask them the very same question. Also a common issue I have been seeing is RPM restrictions on the controller. Our motor will spin significantly faster than what some of controllers can handle. For example, Kelly Controllers.
 
Similar question but different approach. Not trying to Hijack the thread: Please move this / delete it if inappropriate.

I've just received an RP34-313-24volt motor from eBay.

There are a total of 8 wires. 3 are grouped together (I suspect that these are the 3 phase windings, but the wire gauge is not more than 18 or 20ga) and there are 5 other wires. I suspect that they are Hall Sensor leads.

My question is wrt the hall sensor leads, there isn't clearly a red/black pair for power and common with the other three leads as the signal from Hall Effect sensors. Anyone have ideas of sorting these out?

I'd like to use this with a simple brushless DC sensored motor controller. The purpose is for powering my hobby lathe.

Thanks,
Doug
 
how can we figure out which is which when there is no picture?

but i will start the guessing: the one on the right goes with the phase wire on the left and the one in the middle goes with the phase wire on the right and the other wire goes to one of the three wires left. does that help?
 
dnmun said:
how can we figure out which is which when there is no picture?

but i will start the guessing: the one on the right goes with the phase wire on the left and the one in the middle goes with the phase wire on the right and the other wire goes to one of the three wires left. does that help?
Click to expand...

It helps, but not in the way you might imagine. You aren't even good at guessing ;)
If you like pictures, great but the description stands.

There are two connectors. One with 5 wires (presumably the Sensor wires) while the other connector has 3 wires (presumably the coil wires).

image1_resized.jpg

image2 Resized.jpg
 
dnmun said:
the brown and blue go together. white and yellow, grey and green. red and black on the hall sensor plug are 5V and ground.
Click to expand...

So, color blind too... nice!
There is no "red" colored wire in the group of 5, but given the nature of your response,
you likely know that.... thanks for your help.

Doug
 
Hard to tell the wire colors really, from that pic. But one guess might be that the small black wire is either - or +

It will be a bit of a chore, but get a 3 to 5v battery or power supply, and start trying things. See if you can connect + and - to two of the wires, then turn the motor and look for 5v turning on and off all of the other three wires.

A quicker way to dope this out might be to open the motor, and look at which wire is soldered where on the halls. You can look up which pin is +, which is -, and which is signal back. Then follow the wire to the plug and tape on some colors.

The three big wires are phases, normally colored green blue and yellow.
 
dogman dan said:
Hard to tell the wire colors really, from that pic. But one guess might be that the small black wire is either - or +

It will be a bit of a chore, but get a 3 to 5v battery or power supply, and start trying things. See if you can connect + and - to two of the wires, then turn the motor and look for 5v turning on and off all of the other three wires.

A quicker way to dope this out might be to open the motor, and look at which wire is soldered where on the halls. You can look up which pin is +, which is -, and which is signal back. Then follow the wire to the plug and tape on some colors.

The three big wires are phases, normally colored green blue and yellow.
Click to expand...

Thanks Dogman,

I was surprised the size of the coil wires. The ones I've seen on RC brushless motors have been huge by comparison.
I've thought about opening up the motor but am a little worried if, like the stepper motors, alignment can be messed up such that the motor loses a lot of it's torque. Do you think that opening it up would be safe? It would be pretty easy to figure it out by looking at the Halls Sensor leads. :)

I'm not holding my breath, but I've sent a note off to the manufacturer in case they might share the wiring information with me. As the saying goes "you don't ask - you don't get" :)

Thanks again for your reply.
Doug
 
View attachment RP34-313V24-000-X_004 (00000002).pdf

Well, in the interest of closing up this thread, the manufacturer came through with the data sheet (including connections) for this product.

ORANGE
HALL [+]
HALL [-]
BLACK
YEL
S1
GRAY
S2
GRN
S3

These are the Hall Sensor connections. The coil wires were as Dogman suggested :)
Thanks again for the feedback.
Doug
 
dnmun said:
the brown and blue go together. white and yellow, grey and green. red and black on the hall sensor plug are 5V and ground.
Click to expand...


See the Datasheet at the end of this thread. The information in this reply makes no sense at all.
I'd hate someone to read this and try to hook up their brushless motor using the information provided.

Nitrous
 
You must log in or register to reply here.

Similar threads

Andrenav03
Program sine wave 18 mosfet controller help
Replies
9
Views
291
Chalo
Chalo
M
Do dual motors need 2 controllers or is there a single controller option.
Replies
12
Views
485
MikeTinkerer
M
F
    • Like
What controller to buy
Replies
1
Views
913
Chalo
Chalo
B
Can you help me understand this controller from the picture?
Replies
2
Views
482
BiggKidd
B
badboy1999
    • Like
Looking for a ~350w controller
Replies
7
Views
1,133
slaphappygamer
S
Back
Top