Keywords: induction motor drives, direct torque control, DTC, space vector pulse width modulated, SV–PWM, fixed switching frequency, modified stator flux estimator, induction motor, constant switching frequency, simulation, DC drift, saturation, transient response
Modified stator flux estimation–based direct torque controlled induction motor drive with constant switching frequency operation
A space vector pulse width modulated (SV–PWM) direct torque controlled (DTC) induction motor drive, having reduced torque ripple even at low operating speeds and maintaining constant switching frequency has been studied and implemented with a modified stator flux estimation scheme. It utilises a compensator for the phase and magnitude error introduced by low pass filter, which is being used to avoid DC drift, problem of saturation and to enhance the transient response of the machine. Detailed simulation studies are carried out to verify the efficacy of the system. The viability of the scheme is confirmed by performing detailed experimental studies.