DEVICE FOR DETERMINING THE FLUX VECTOR OF AN INDUCTION MACHINE FROM STATOR CURRENT AND STATOR VOLTAGE

摘要

An EMF detector supplies, from the voltage and the current, the EMF vector in a coordinate system fixed in space, the integral of which is the flux vector. The integration is carried out in the field oriented coordinate system, in which the EMF vector is transformed by means of a vector rotator. A rotational component is taken into consideration in the integration by having a first integrator form, from the field parallel EMF component, the magnitude of the flux and having a divider form, from the second EMF component and the magnitude of the flux, the flux frequency, from which frequency an integrator forms simultaneously the flux angle and the angle of rotation for the vector rotator. An angle control input characterizing the steady state and the angle of rotation, through an angle servo control selectably furnishes the field frequency entered into the second integrator to form, from a magnitude servo control, a feedback signal added to the field parallel EMF component. Further provided are circuits for taking into account the stray inductance without differentiation and a circuit for stabilization and damping.