Hi,

Recently i am working on direction and speed control of bldc motor.

i am stuck on one thing, that is how can i start-up bldc motor from 0 to given speed, like how it starts if i give 900 rpm.

Thanks

 

You should find some useful information if you google:
sensor bldc ap note
(the search also returns sensorless if that's what you are going for).
I know that some of the Microchip ones are quite detailed on the theory, which will apply to other microcontrollers.

 

Thanks Mrakd77,

but i am not looking into microchip, i just need some tips of it, that how it starts from 0 to given voltage, and i m working on sensored bldc motor, on google it shows about sensorless. sometimes it confuse alot.

 

A BLDC motor needs a controller. What are using for the controller? There are IC chips to do it with out a micro, but you do need some type of controller.

 

i am using pwm to control or pid to control

 

like starting function or start-up of bldc motor.

if i give the reference voltage of 1000 rpm, how it start working, the theory how the rotor starts with magnetic flux. in little detail.

Thanks.

 

Since the BLDC motor as no brushes or commutator, PWM or PID will not make it turn. It needs a controller. The Hall sensor outputs tell the controller when to turn on the upper and lower mosfet switches. It takes six switches to create the voltage pattern to the stator coils. Having a certain voltage level without the controllers logic will only tend to make heat in what ever phase happens to be turned on.

Here is a link to explain the working;
http://www.google.com/url?sa=t&rct=...EAd1gyNZIF-5N1RFAHfyJoA&bvm=bv.47244034,d.aWc

 

i am using spwm in matlab/simulink and pid controller to control error, the

required speed.

here is little example of what i need, bldc motor has permanent magnet rotor, when input the voltage the rotor, the repels and rotor starts moving.

i need this thing in little detail.

 

Did you even read the link? If you won't do some of the work/reading, why would you even bother to ask a question here? The BLDC is an electronically commutated motor, it will not turn just by supplying a voltage haphazardly to the wires. It takes control logic to make it turn. The voltage is not increased to speed it up, the frequency of commutation is increased. Do a Google search and read about it.

 

thanks shortbus and mark, i have solved this problem, i did alot of reading on it and finally got anserws.