Modeling and Analysis of Common-Mode Voltages Generated in Medium Voltage PWM-CSI Drives

Common-mode voltages appear in pulse-width modulated current-source inverters (PWM-CSIs) drives due to the operating principles of the input rectifier and the output inverter. This paper presents the modeling and analysis of a medium voltage current-source inverter drive, using the Matlab software. Simulated results of the model are in close agreement with experimental waveforms obtained from an industrial ac drive, which shows overvoltages of up to 100%, generating important insulation stresses at the motor stator terminals.