ABSTRACT
As it was explained in section 1.2, the basic controlled variable in an electrical drive is usually the angular speed (t), which ideally should be equal to its reference z(t). In a synchronous motor, used in electrical drives, there are two independent operating influences outside the stator. Creating the basic magnetic flux by an excitation winding from outside the rotor opens up an additional possibility to control the electrical drive along with angular speed control. It is possible to achieve better electrical drive performance, e.g., by getting the largest possible efficiency while keeping the power factor equal to one. The desirable electrical drive mode can be achieved by selecting the appropriate reference for the control variables.
