Patent ID: 6335607
Filing Date: 2002-01-01
Classification: H02P

Abstract:
A method of correcting the flux midpoint in flux-controlled alternating current systems, the method comprising the steps ofdetermining a stator flux estimate (&psgr;s,est) and determining the magnitude of stator current (is), wherein the method also comprises the steps offorming the scalar product between the stator flux estimate (&psgr;s,est) and the stator current (is) in order to obtain a reference variable (k), low-pass filtering the reference variable (k) in order to obtain a low-frequency component (kfilt) of the reference variable (k), subtracting the low-frequency component (kfilt) from the reference variable (k) in order to obtain a difference variable (e), determining correction term components (&psgr;s,x,corr, &psgr;s,y,corr) of the stator flux estimate (&psgr;s,est) by multiplying the difference variable (e) by the components (&psgr;s,x,est, &psgr;s,y,est) of the stator flux and correction coefficient (K104 corr), and forming a stator flux (&psgr;s,fin) with a corrected midpoint on the basis of the components (&psgr;s,x,est, &psgr;s,y,est) of the stator flux estimate and correction term components (&psgr;s,x,corr, &psgr;s,y,corr).