Over-voltages of IGBT based PWM inverter fed induction motor drives

This paper deals with the problem that arises in adjustable speed drives motors. It throws light on the different reasons for the occurrence of over-voltages at an induction motor´s input terminals when it is fed by a PWM inverter used for adjustable speed drive applications. The travelling wave theory is studied to understand impedance mismatch phenomenon. Simulation results show that the cable length and turn-on time of the switching device influence this over-voltage to a greater extent. High frequency modelling of the inverter, cable and the induction motor has been done for accurate results.