Analytical Estimation of Torque Ripple and its Minimization in Open-end Winding Induction Motor Drive using Dodecagonal Voltage Space Vector

Lower-order pulsating torque is the main issue in the high-power drives and high-speed operation of the motor drive. To eliminate pulsating torque of harmonic order such as (6m; m=odd number) for full modulation range (MR) in an induction motor (IM) drive a dodecagonal space vector pulse width modulation (DSVPWM) technique is used. This PWM technique is used in open-end winding induction motor (OWIM) drive. One end of the motor terminals is connected primary inverter with dc bus voltage is (Vdc) and another end is connected secondary inverter with dc bus voltage (0.366Vdc). In this paper analytical Fourier series expression for the resultant phase voltage waveform is derived from the inverter-1 (inv-1) and inverter-2 (inv-2) phase voltages. This analytical expression proven that all (6m±1; m=odd number) phase voltage harmonics are eliminated in the OWIM drive. This paper also explains the instantaneous torque ripple evaluation based on the single-phase equivalent circuit of the IM. Torque harmonic order of (6m; m=even number) is evaluated analytically at the extreme 12-step operation which is validated with MATLAB simulation results.