Impact of reduced common mode voltage PWM and common mode inductor on EMI characteristics of an inverter-driven motor

Pulse width modulation (PWM) inverters have been widely used in the variable-speed motor drive. However, the common mode voltage (CMV) and common mode current (CMC) produced by PWM inverters cause EMI to electronic equipments around. This paper experimentally investigates the CMV/CMC characteristics of important reduced CMV PWM methods, such as active zero state PWM1 (AZSPWM1), near state PWM (NSPWM) and three-dimension AZSPWM (3D-AZSPWM), for a two-level three-phase voltage source inverter, with and without a common mode inductance (CMI). Experimental results are helpful to the research of the EMI characteristics of the inverter-driven motor and suggest that a combined algorithm using 3D-AZSPWM and NSPWM with a CMI inserted makes a promising way to improve its EMI characteristics.