how we can consider an "error" to control the reactive power in DFIG

Discussion in 'The Projects Forum' started by, Mar 12, 2013.


    Thread Starter New Member

    Feb 21, 2013
    hello every body
    in a wound rotor induction machine >>electromagnetic torque(Te) with neglecting of rotor and stator resistor losses is equal to:
    {w1:angular speed of stator winding,wslip:angular speed of rotor winding,Ps=instantaneous power received from stator terminals ,Pr=instantaneous power delivered to rotor terminals}

    {Tmech:mechanical torque,wr:rotor speed ,in generating, Te<0 ,Tmech>0,in generating, Te>0 ,Tmech<0}

    in field oriented control
    (3)Te=-3/2*p*Lm/Ls*flux_s_d*irq [2]

    {flux_s_d:stator flux (direct axis component),Lm:mutual inductance,Ls:stator inductance,p : pair pole,irq:current of rotor (quadrature axis component)}

    from (2) we can consider the "error of rotor speed from a reference speed"as electromagnetic torque,and then from(3) we can consider it as irq
    hence we can control the rotor speed with irq

    in that article[2]
    idr(direct component of rotor current) is considered to control the stator reactive power
    i don't know how we can consider an "error" to control the reactive power (similar to control the rotor speed with equation (2))?
    note that from another article[3] we have:
    for the rotor side converter,articles [2],[3] are based on the synchronous reference frame fixed to the stator flux.

    Please discuss your opinions

    [1]variable speed generators(ION BOLDEA)
    [2]Doubly fed induction generator uising back-to-back PWM converters and its application to variablespeed wind-energy generation(R. Pena,J.C.Clare ,G. M. As her)(1996)
    [3]Coordinated reactive power control for facilitating fault ride through of doubly fed induction generator- and fixed speed induction generator-based wind farms(S. Foster, L. Xu, B. Fox)2008