Voltage gradient suppression in application of voltage-fed PWM inverter to AC motor drives-resonant DC link inverter approach

In this paper, a hazardous phenomenon which occurs when the switching device of an inverter switches very fast or when a cable feeding a motor is very long is described and a suppression method for the voltage transition gradient of the voltage source inverter is presented. By using the resonant circuit in the DC link of the inverter, the inverter output voltage gradient at the switching moment can be suppressed. Compared to the hard switching inverter, the suppression of the voltage rise gradient and the performance of the proposed inverter in the control of the motor are verified through the experiment.