Method for the formation of the actual load angle value for a field-oriented regulated rotary field machine and corresponding regulation

DETAILED DESCRIPTION With field-orientation it is achieved that the field-parallel and the field-perpendicular components of the nominal current vector can be impressed on the machine independently of each other.
The field-parallel component which corresponds to the field current of a dc current machine can be controlled or regulated, and thus and the flow of the machine can be adjusted to the desired value.
The field-perpendicular component permits adjusting the turning moment to a controlled or (for example by means of a speed regulator) regulated given nominal value.
The above and other objects of the invention are achieved by a method for the formation of an actual load angle value for field-oriented regulation of a rotary field machine, comprising the steps of forming from a field-oriented nominal voltage vector, a direction of the field-oriented nominal voltage vector, forming from an angle difference between a stator-oriented actual voltage vector and the field-oriented nominal voltage vector, a stator-oriented field angle, and forming from the difference of a measured stator-oriented angle of the actual stator current vector and the stator-oriented field angle the actual load angle value.
In the case described up to now of current impression in a voltage-impressing converter, current regulation for the two orthogonal (cartesian) components of the current vector was used.
It is, however, also possible through a cartesian/polar coordinate conversion to form from the field-oriented nominal current components the nominal load angle and undertake a regulation of the load angle, i.
e.
the angle between the stator current vector and the flux vector (in particular the rotor flux vector).
However, neither the flux vector itself nor the angle between it and the stator current vector is accessible to direct measurement but must be determined through calculations, for example via the stator voltage vector and the stator current vector.