Output deviations in digitally controlled asynchronous motors

The authors deal with some problems raised by the application of digital control to asynchronous motors. At first the mathematical model of a digitally controlled asynchronous motor is described, which allows a step by step evaluation of the main electrical and mechanical motor quantities. Then, it is used to evaluate currents and torqued ripples due to the digitalization of signals processing and numerical examples are shown for a sample asynchronous motor and for different feeding algorithms. It is finally shown that an easy analytical law exits between torque deviations and sampling period and that it can successfully be used for control designing purposes