Calculation of slip energy recovery induction motor drive behavior using the equivalent circuit

A transformer-type equivalent circuit model for the calculation of the steady state performance of a slip energy recovery induction motor drive with a step down chopper in the DC link is described. Experimental data of RMS currents, power, reactive power and overall efficiency satisfactorily correlate with calculations over most of the operating speed range. Also, detailed calculations of rotor, stator and supply harmonic currents due to the rectifier and inverter actions are performed using the conventional version of the equivalent circuit. The computed and measured instantaneous current waveforms show satisfactory agreement except at a slip of 1/6 where significant deviations appear. This effect is adequately catered for by using a more rigorous model