Experimental Investigation of Sub-Cycle Voltage Reductions in a Slip-Ring Induction Motor Using a Computer-Aided Measurement System and MATLAB/Simulink Validation

This paper presents an analysis of the impact of sub-cycle voltage reductions (below 1 ms) on the operation of a slip-ring induction motor. Due to the specific design of the slip-ring induction motor and the presence of a separate rotor circuit, direct measurements of rotor currents and voltages are possible, enabling a more detailed analysis of the physical phenomena occurring in the machine. A series of experiments was conducted using the Profline 2100 device, which enables the generation of controlled sub-cycle voltage reductions. This made it possible to directly assess the influence of such disturbances on motor operation, particularly changes in stator and rotor currents, rotational speed, and electromagnetic torque pulsations. The electrical and mechanical parameters of the motor were also identified. The obtained data were used to develop a mathematical model and implement it in the MATLAB/Simulink environment, enabling qualitative reproduction of the observed phenomena. The main novelty of this work is the analysis of the electromagnetic response of a slip-ring induction motor to sub-cycle voltage reductions below 1 ms, supported by direct measurements in the rotor circuit. The resulting model, validated against measurement results, shows qualitative agreement with the experiments and enables a more detailed analysis of motor dynamics during sub-cycle voltage reductions, including phenomena that are difficult to capture experimentally.