Understanding BLDC Motor Control: Position, Speed, and Current

In summary, the Maxon E40 motor can be controlled with a PID controller, but torque and current are also propotional with the load.
  • #1
bagavac
1
0
Hi guys,

I'm developing a BLDC motor controller with load. I've bought a Maxon E40 motor . But some things i can't figure out:

I want to control position, speed and current (torque). I use PID controller to do it. In the closed loop system the output of the speed controller should be input of current PID controller.

questions:

1) is this above true?

2) is it true that the torque and current are propotional also with the load?

example: If the torque constant is 2Nm/A and my load is 1Nm i need 0,5A to move the load? or is the torque constant only propotional on no loaded motor...?

btw: why is it needful to controll the current?
 
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  • #2
BLDC motor in printer

I am studying about BLDC motor.
My teacher gave me a BLDC motor which is in printer machine.
however I don't how to control.
It has 11 unknown outputs.(its seems to be use HALL IC 4 pins)
I have some pic about my motor but i don't how to post.
If there is anyone knowing about it.give ur opinion.
Thanks you very much.
 
  • #3
bldc motors are a bit complicated. there's some tutorial around the web explaining how BLDC's work. Last i work on it few months back, the current supplied controls the speed of the motor. current is controlled by chopping the driver or somewhat essentially shutting it on/off. i was using A3936.

a BLDC motor typically has 8 connector. 3 for each motor phase, 3 for hall sensor (1 sensor for each phase), 1 power supply Vcc for sensor, 1 gnd for sensor.

yes the output of the hall sensor goes back to the input. you get the timing from the motor poles through the hall sensor. from this timing, # of motor poles etc you can find the rpm of your motor. based on this result, you compare with what speed you want (ie: your speed corresponds to some timing). Increase/decrease your current to get that speed.

I got mine to work but I'm not sure if it works right. Mainly because torque is also a factor of current and speed. if you go too slow, you lose torque. So if you want to use brushless and run slow, you have to use a gear to down convert the speed.

hope this helps
 
  • #4
He.Thanks your opinion.
I controlled a typical BLDC motor as you say.
but the BLDC motor in printer is differ form a typical motor.
while a typical motor uses HALL sensors ,my BLDC motor uses HALL IC.
He.I can send you some info abt my BLDC motor?
Give me your email to contact!
Ok!thanks for ur help!
 
  • #5
what is the chip? Can you look at the data sheet for the chip. More information is required. What are your 11 pins,
 
  • #6
hi.i don't know how to decribe.
it will be more convient if we can contact each other by email.
are you ok?
 

1. What is a Brushless DC motor?

A Brushless DC motor is a type of electric motor that uses electronic commutation instead of mechanical brushes to control the movement of the rotor. This results in improved efficiency, reliability, and longevity compared to traditional brushed DC motors.

2. How does Brushless DC motor control work?

Brushless DC motor control uses sensors to monitor the position and speed of the rotor and sends this information to a controller. The controller then adjusts the amount of power supplied to the motor's windings to control its speed and direction of rotation.

3. What are the advantages of using Brushless DC motor control?

There are several advantages to using Brushless DC motor control, including higher efficiency, improved reliability, and longer lifespan. Brushless motors also produce less electrical and mechanical noise, making them ideal for applications that require low noise levels.

4. What are some common applications of Brushless DC motor control?

Brushless DC motor control is used in a wide range of applications, including electric vehicles, robotics, industrial automation, computer hard drives, and HVAC systems. They are also commonly used in drones, power tools, and household appliances.

5. How do I choose the right Brushless DC motor control for my application?

Choosing the right Brushless DC motor control depends on several factors, including the required torque and speed for your application, as well as the power supply and communication protocol needed. It's important to consult with a knowledgeable supplier or engineer to select the best motor control for your specific needs.

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