[SOLVED] dc motor speed controling

[alipoor90]

hi guys
i want to control dc motor speed with pwm(and full or half bridge with mosfet) and i want to select best method to have smother motor movement
1- is better to cut off motor current in Toff
2-or short circuit motor (with freewheel diode or ...)
3-or cut off motor current and use RC snubber to reduce motor energy level
thanks
ali

 

[Dinuwilson]

i think PWM is one of the best methode....you use somesome microocntrollers for pwm generation. or pwm ic's. and power switching devices.

 

[alipoor90]

sorry for my weak English
my problem isn't about pwm generating
i want to have smoother movement in motor and reduce motor vibration
i know if i change frequency i don't have vibration any more
but i want to know with which of these methods i have less vibration
thanks
ali

 

[nitrojacob]

The best way will be to provide a clean DC to the motor input. The closest you can practically get, in my opinion, is to use the PWM to control a Buck Converter. The DC motor can be used as the capacitor of the buck circuit.

 

[goldsmith]

hi guys
i want to control dc motor speed with pwm(and full or half bridge with mosfet) and i want to select best method to have smother motor movement
1- is better to cut off motor current in Toff
2-or short circuit motor (with freewheel diode or ...)
3-or cut off motor current and use RC snubber to reduce motor energy level
thanks
ali

Hi Ali
It depends on how much is nominal power of your motor . if it isn't so high power , then you can easily use an snubber network .
By the way if you use a 2nd order filter before your motor , then you won't have any special problem and it's controlling will be so precise !
Best Wishes
Goldsmith