Modified Field Oriented Control Based Kramer Drive for Wound Rotor Induction Motor with Sinusoidal Machine Current and Voltage

This paper presents Field Oriented Control (FOC) of modified Kramer drive with back-to-back SCR based converters in rotor side of an asymmetric WRIM. The rotor side SCR converter is operated to ensure proper current control in rotor side. The line side converter is operated to maintain DC link current constant (based on load torque demand). A two level VSI is connected on rotor side to compensate current harmonics to make rotor currents sinusoidal and inject reactive power for the thyristor commutation. The proposed drive can be operated in both sub-synchronous and super-synchronous speed range. Proper modelling of each unit of the proposed system along with their control is shown in this paper. Due to sinusoidal current and voltage at machine terminals the efficiency of the drive increases and promising improvement in torque profile can be obtained. To validate the proposed topology MATLAB/SIMULINK environment is used.