Experimental investigations on flux estimation of a variable frequency IM drive

An experimental investigation of stator flux linkage is performed on a three Phase induction motor drive. In the proposed investigation, theoretical aspects of a pure integrator and its impact on the estimated stator flux waveform are presented. DC component present in the input signal to be processed leads to integrator saturation, results a ramp signal at integrator output. Thus, implementation of a low pass filter in a pure integrator for eliminating its saturation effect is also proposed. Also, the effect of cut off frequency on the stator flux linkage is observed. The experimental investigation is validated on a 1 H.P. induction motor, a digital inverter controller, an IGBT power module and dSPACE Controller Board (CP1104). dSPACE is configured using MATLAB/Simulink. Real time signals like three phase currents, PWM Pulses and a fixed DC link voltage are the input parameters to the dSPACE controller board.