Analytical closed-form investigation of PWM inverter induction-motor drive performance under DC-bus voltage pulsation

This paper presents an analytical closed-form mathematical model and analysis of the influence of the DC-bus ripple voltage of the three-phase voltage source inverter (VSI) with the space-vector PWM (SVPWM) on the induction machine phase voltages, currents and torque pulsations. The analytical expressions for the voltage and current space-vectors as a function of the dc-bus voltage pulsation are derived. Using superposition we can determine the separate parts of the motor currents. Next, it is shown, that dc-link voltage ripple components may cause large torque pulsation. The proposed analytical method is based on the mixed p-z approach, enabling presentation of the results in lucid and closed-form. To verify the effectiveness of the proposed analytical model, experimental results based on laboratory setup,were obtained.