Analytical Investigation of Influence of DC-Link Voltage Ripple on PWM VSI Fed Induction Motor Drive

Analytical analysis and mathematical model of three-phase voltage source inverter with space-vector PWM feeding an induction motor drive under DC-link ripple voltage components are presented in this paper. The analytical expressions for the voltage and current space-vectors as a function of the DC-link voltage pulsation are derived. From the current space vectors the torque behavior is estimated again as a function of DC-link voltage pulsation, it was shown that DC-link ripple voltage components with angular frequency omega₀ may cause large torque pulsation with the same angular frequency. The proposed analytical method is based on the mixed p-z approach enabling presentation of the results in lucid and closed-form