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PMSM

DIJO PAULSON
Intellectual 710 points


Hi, 

My PMSM motor is rated for 200 V, 3000 rpm, 200 Hz rated freq . Does it mean that when i give 200 V  and 200 Hz  it would reach at it's rated RPM. How is this 200 Hz  achieved by the controller since I am giving only 50 Hz supply.? 

Regards,

Dijo Paulson.

  • 0
    TI__Mastermind 27240 points
    Dijo,

    You will have to use a rectifier to convert the ac to dc and then use an inverter to generate the voltage and frequency to run the motor at 3000 rpm.
  • 0 in reply to Ramesh Ramamoorthy
    Intellectual 710 points
    Thank you Ramesh,

    I am beginner to the motor control world.
    Can you just explain what is the significance of V/f ratio ?
    Do we need to maintain a constant V/f ratio just as in the case of induction motor ?

    Regards,
    Dijo Paulson.
  • 0 in reply to DIJO PAULSON
    TI__Mastermind 27240 points

    Dijo,

    To cut a long story short, the back emf voltage is proportional to frequency and airgap flux.

    back emf  = k.freq.flux

    generally bemf ~= applied emf

    Speed is proportional to frequency, or speed = freq / polepair

    If you want to operate the motor with constant flux(for quick torque response you need this), then as you change the frequency, you will also need to change the applied voltage to keep the currents under control  and to balance the load torque.

    There are plenty of good books available on this topic. Suggest to refer any of them.

    rgds,

    ramesh