control a 3 phase 48 volts ac motor

Discussion in 'General Electronics Chat' started by sujinvipin, Aug 18, 2011.

  1. sujinvipin

    Thread Starter New Member

    Aug 18, 2011
    How to control a 3 phase 48 volts ac motor by a dc supplied inverter?
  2. strantor

    AAC Fanatic!

    Oct 3, 2010
    never seen a 3 phase 48V motor
    you want to build an inverter? I think it would be more cost effective and time effective for you to buy one that has DC bus terminals.
  3. praondevou

    AAC Fanatic!

    Jul 9, 2011
    You can do it with a microcontroller that can provide 3x 120 degree phase shifted PWM signals (sine wave modulated), pass them to 6 IGBT drivers and then to the IGBTs and then to the motor. No big filter necessary, your motors inductance creates the sine wave current. Also, you need a rectifier to create your DC-bus voltage...If there is load on the motor you need also a circuit to keep the DC-voltage low in case you decrease the motor speed, it will work as a generator increasing your DC voltage unless you can feed the energy back to mains, so you need to burn this energy in a resistor.
    The PWM also needs to be programmed to increase the current through the motor gradually (in a ramp).

    You see, it's complex.

    If you are a beginner don't try to build one... buy one :D That's a big project.