The impact of deterioration of the absolute position transducer on the electric drive with Permanent Magnet Synchronous Motor

The paper presents mathematical model of absolute optical encoder with parallel gray output where various parameters of the transducer can be modified (ex. number of bits, asymmetry in output waveforms, lack of signals from selected bits). The model of the non - ideal encoder substitutes the model of ideal position sensor implemented in Matlab/Simulink model of three phase PMSM (Permanent Magnet Synchronous Motor) drive with SVPWM (Space Vector Pulse Width Modulation) control algorithm. The author examines the impact of: asymmetry in output signals from the encoder and absence of signals from selected bits (simulation of damage of the transducer) to the static and dynamic properties of the drive in current and speed control loop mode. Selected methods of signal improvement were implemented in order reproduce the degradated position signal. The simulation results are verified by experiment. Quality indicators are proposed in order to determine the rate of damage of the encoder/drive. Conclusions and proposes of further research are presented.