Abstract: The intention is to simplify the measurement of an inductance characteristic curve of a motor. To this end, provision is made for a current (i) having a non-periodic current offset component and a periodic current component to be injected into the motor's winding so that the motor accelerates. A corresponding voltage (u) across the winding is measured and a voltage interference component and a periodic voltage component are determined from the measurement. The inductance of the winding can finally be determined from these two components. It is thus possible to dispense with the operation of blocking the motor or to dispense with an expensive motor test rig in order to determine the inductance characteristic curve.

Abstract: In a method for determining the rotor position of a synchronous motor, a plurality of current vectors having different directions is applied to the synchronous motor. Absolute values of required ones of the current vectors are determined to obtain a defined excursion of the rotor. Inverse values of the determined current vectors are then digitally filtered using several of the inverse values to determine Fourier coefficients of the first harmonic of the inverse values. The rotor position of the synchronous motor can then accurately be computed with the determined Fourier coefficients.

Abstract: A method and a system for identifying a faulty rotor position angle signal of a synchronous motor powered by a converter, wherein a first flux angle is determined from the rotor position angle signal, wherein from the motor currents of the synchronous motor a current pointer is determined, wherein from a voltage pointer of the motor voltages of the synchronous motor and the current pointer a second flux angle is determined using a flux modeler of the synchronous motor, and wherein in the event of insufficient agreement between the first and second flux angle a faulty rotor position angle signal is identified.

Abstract: Damping of mechanical oscillation in a shaft that is provided by feedback wherein the output signals of multiple feedback devices are negatively coupled and added to a desired speed signal of a motor speed controller of the driving motor is disclosed. At least one sensor and/or measuring system can be provided for measuring an actual position value. The actual speed of the shaft can be determined by differentiation from the shaft position value measurements or by integration from shaft acceleration measurements. The measured or actual speed of the shaft can be supplied as an input signal to each feedback element. Each feedback element is specifically tuned to an oscillation frequency range of the shaft that is to be damped. The invention provides an easy and cost-effective way of damping mechanical oscillations that have limited frequency ranges.

Abstract: According to the invention, the controller cascades are suitably divided up and the oscillation damped only in the load rotational-speed controller. Here, a motor rotational-speed setpoint value (z) of a quickly regulated motor rotational-speed controller (9) and not the motor torque, is selected as the connection point for a load acceleration (i). In order to achieve a shorter transient response time, according the invention the difference between a setpoint rotational speed (x) and load rotational speed (y) is connected to the motor rotational-speed setpoint value (z). The solution in principle according to the invention which is presented has, in contrast to other known methods, the advantage that the actuation of the corresponding controllers is comparatively simple with very good control results.

Abstract: A process and device for field-oriented control of a polyphase machine, where a torque-producing quantity is regulated via a speed control circuit and a flux-producing quantity is regulated via a field control circuit that determines the magnitude and angle of the flux. The flux magnitude is injected through the field control circuit. Orientation errors in the field axis are corrected through frequency adjustment, specifically by adjusting the slip frequency according to the difference between the transformation angle used and the flux angle. The voltages and currents that create the rotational field of the machine are generated via a current control circuit in accordance with the corrected reference values.