motor controller for a 48v bldc motor

Thread Starter

ncccengineering

Joined Nov 20, 2013
31
I am working on a school project and i'm working with a design team to make a simple motor controller for a 48v 40a bldc motor. We are just a high school class and have no experience with this topic. Anything you could do to point us in the right direction would be great.
 

ronv

Joined Nov 12, 2008
3,768
That's a project that can smoke a lot of expensive parts.:eek:

You can go to one of the major suppliers like Mouser or Digikey and look under power management for brushless motor controllers. You need to tell us more about your motor. A spec. would be best. But for sure the number of phases and if it has sensors or not.
 

MaxHeadRoom

Joined Jul 18, 2013
18,862
The Picmicro site has info on BLDC control or the Freescale (Motorola) semi site has dedicated IC's for this application.
Typically you would have hall effect commutation, or at least the equivalent tracks on the encoder, if fitted.
40amp motor is fairly large!
Max.
 

Thread Starter

ncccengineering

Joined Nov 20, 2013
31
This is the specs from the website we bought it from:
Electric trike motor brushless 48V/60VDC 750W
The 48V 750W brushless dc tricycle motor main specification:
No load current: ≤5.0A
Rated power:750W
Rated speed:2800RPM
Rated torque:2.56N.m
Rated current:≤20A
Efficiency:80%
Ratio: 6:1
Real speed:480RPM
Weight:6.8KG
Motor phase angle:120℃
Motor dimension: 26CM*13*CM*15.5CM
Load Capacity:500KG



This is for the 48V 750W brushless motor.
 

ronv

Joined Nov 12, 2008
3,768
Ahh, I see.

OK. So a couple more questions:
Does it need to go in forward and reverse or just forward?
Somewhere I thought I saw the wiring for the plug, but I can't seem to find it again. It had hall sensors, but I can't remember the voltage for the hall sensors.
I seems to be a 3 phase motor (120 degrees).
How will you control it? With a micro controller or do you just want a control to adjust the speed (like a volume control)?
 

Thread Starter

ncccengineering

Joined Nov 20, 2013
31
Ahh, I see.

OK. So a couple more questions:
Does it need to go in forward and reverse or just forward?
Somewhere I thought I saw the wiring for the plug, but I can't seem to find it again. It had hall sensors, but I can't remember the voltage for the hall sensors.
I seems to be a 3 phase motor (120 degrees).
How will you control it? With a micro controller or do you just want a control to adjust the speed (like a volume control)?
This motor only has to go in forward.We do not care about going in reverse. I do not know what you mean by "wiring for the plug." Also, I was unable to find anything about hall sensors. The specs that I put in a previous post is all that I am aware that we have.

Would this be an acceptable IC : http://www.apexanalog.com/wp-content/uploads/2012/10/SA306U_H.pdf

This was offered as an idea earlier: http://www.mouser.com/ProductDetail/International-Rectifier/IR3230SPBF/?qs=hC%2b8fpRoqiJWKVeH05n7DA==&gclid=CPKirInF-LoCFQbl7AodUUoArQ But my team and I could only find a pwm input not an output.

We aren't dead set on a pwm; however, we feel that it is the most efficient. Any advice that you can offer is a HUGE help!
 
Last edited:

Alec_t

Joined Sep 17, 2013
10,267
Would this be an acceptable IC
No. Its rated current is only 15A.
But my team and I could only find a pwm input not an output.
The PWM input defines the duty cycle and frequency. The six Ho and Lo outputs convey the necessary PWM drive signals to the high and low side FETs.
 

ronv

Joined Nov 12, 2008
3,768
By plug I mean the diagram that describes what each of the wires coming out of the motor is used for. It's on the internet somewhere, but you can look for it as easy as I.
 

Thread Starter

ncccengineering

Joined Nov 20, 2013
31
By plug I mean the diagram that describes what each of the wires coming out of the motor is used for. It's on the internet somewhere, but you can look for it as easy as I.
Yes we have found that diagram. We actually have the motor in our possession along with its motor controller; however, for our competition we have to purpose design and build our own motor controller. We can't buy one off the shelf. (We do have the motor and controller hooked up and we know what each wire is supposed to do.)
 

Thread Starter

ncccengineering

Joined Nov 20, 2013
31
No. Its rated current is only 15A.
The PWM input defines the duty cycle and frequency. The six Ho and Lo outputs convey the necessary PWM drive signals to the high and low side FETs.
So does that specific IC actually do PWM ?
 

ronv

Joined Nov 12, 2008
3,768
You need to provide the pwm input along with forward reverse enable and such.
So can you post a link or a picture of the motor wires?
 

Thread Starter

ncccengineering

Joined Nov 20, 2013
31
Attached is the diagram we have for the wires coming out of the motor. If you would like I can attach a picture of the motor, but I felt like this was more helpful.
 

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Alec_t

Joined Sep 17, 2013
10,267
The PWM and direction control signals would typically be provided using a micro. A suitable PWM signal could also easily be generated by a conventional 555 circuit.
 
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