Siemens Aktiengesellschaft

Karl-Heinz Bayer

Felix Blaschke

Ingemar Neuffer

Wolfgang Michel

Process for optimizing efficiency in ships with bow and stern screws and

Disclosed is a method to detect the rotor resistance of an asynchronous machine, wherein a first vector attached to the emf of the machine is determined by computing the emf-vector or the flux vector from the stator voltages and the stator currents; wherein a flux attached to an arithmetic model circuit is determined, whereas the arithmetic model circuit uses the stator currents and the rotor position of the machine and an adjustable model parameter for the rotor resistance as basic quantities and imitates the dynamic events leading to the magnetic flux of the machine; wherein a difference of two quantities is determined, wherein the first quantity represents a defining quantity of the first vector attached to the machine and the second quantity represents a respective defining quantity of a second vector derivable from the imitated flux and that the setting of a model parameter is varied until the value of the difference is a minimum, whereas the model parameter corresponding to the minimum of the difference is regarded as the resulting rotor resistance of the machine.

Method and apparatus for determining the rotor resistance of an

A vector analyzer which serves for determining defining quantities of a planar vector in which the output of a digital counter is fed, via sine and cosine function generators, to a vector rotator addressed by the component voltages of an input vector and made to follow the value of the phase angle of the input vector by means of a three point control in order to make the output of the digital overflow counter follow the phase angle of an input vector by means of a control loop; the counter content is reset to zero without problem if the value 360.degree. of the phase angle is exceeded. The invention can be used particularly for field orientation control of rotating field machines.

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Erlangen, Germany

Karl-Heinz Bayer