Common-Mode Voltage Reduction PWM With Minimized Current Distortion for Two-Level Voltage Source Inverter

This article proposes a new pulsewidth modulation (PWM) method to reduce common-mode voltage (CMV) in a two-level voltage source inverter. Large CMV may result in common-mode current-induced issues, such as electromagnetic interference and motor bearing degradation, in motor drive applications. Although various reduced CMV-PWM (RCMV-PWM) methods have been developed to mitigate CMV, they have main drawbacks in large switching current ripple. To alleviate this tradeoff, the proposed PWM method is designed to suppress CMV while minimizing the switching current ripple under the reduced-CMV constraint by selecting voltage vectors close to the reference voltage. The proposed PWM method can be easily implemented using carrier-based PWM and 30° discontinuous PWM offset voltage. The performance of the proposed PWM is comparatively evaluated against conventional RCMV-PWM methods, and its effectiveness is verified through comprehensive analytical and experimental results.